Water softening device

Abstract

A water softening device (1) is provided with: a water softening tank for generating soft water by softening raw water containing a hardness component using a weakly acidic cation exchange resin (33) in a water softening step; a neutralization tank for neutralizing the acidic soft water that has passed through the soft water tank in a soft water treatment step by using a weakly alkaline anion exchange resin (34); an electrolytic tank (9) for generating electrolyzed water used in the regeneration step; an adsorption amount identification unit for identifying the ion adsorption amount of a specific ion species in the soft water tank on the basis of the ion concentration of the raw water, which is the ion concentration of the specific ion species in the raw water, and the amount of the raw water introduced into the soft water tank; and a control unit (15) that controls the execution of the regeneration step on the basis of the ion adsorption amount identified by the adsorption amount identification unit. The control unit (15) is configured so as to execute a replacement step in which the operation of the electrolytic bath (9) is stopped, the acidic electrolyzed water in the softened water tank is discharged, and the raw water is introduced into the softened water tank when the operation time of the regeneration step reaches a reference operation time.

Description

Technical Field

[0001] The present disclosure relates to a water softening device. Background Art

[0002] In conventional water softening devices, a method of regenerating a cation exchange resin using acidic electrolyzed water generated by electrolysis is known as a method of regenerating the cation exchange resin without using common salt (for example, see Patent Document 1).

[0003] Weakly acidic cation exchange resins have protons at the ends of their functional groups and soften the raw water by exchanging hardness components (e.g., calcium or magnesium ions) for hydrogen ions. Raw water softened with weakly acidic cation exchange resins contains hydrogen ions and is acidic. The hydrogen ions in this softened raw water are adsorbed onto the weakly basic anion exchange resin along with anions, neutralizing the softened raw water.

[0004] In conventional water softening devices, a method of regenerating a weakly basic anion exchange resin using alkaline electrolyzed water generated by electrolysis is also known (for example, see Patent Document 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-30973

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-142674 Summary of the Invention

[0009] Such conventional water softening devices use an electrolytic cell that generates acidic electrolyzed water and alkaline electrolyzed water by electrolyzing water.

[0010] During ion exchange resin regeneration, hydroxide ions in the alkaline electrolyzed water generated at the cathode exchange with anions such as chloride ions adsorbed to the weakly basic anion exchange resin during water softening, releasing the chloride ions and other anions from the ion exchange resin. The released anions migrate from the cathode to the anode due to the electrolysis of the water in the electrolytic cell.

[0011] Therefore, in a water softening device that re-electrolyzes the acidic electrolyzed water used for regeneration and reuses it for regeneration of the ion exchange resin, the anion concentration of the acidic electrolyzed water on the anode side gradually increases as the regeneration of the ion exchange resin proceeds.

[0012] When a platinum-based electrode catalyst material is used as the anode in an electrolytic cell, this increase in anion concentration may cause the platinum component to dissolve or desorb, leading to a decrease in catalytic performance.

[0013] If the catalytic performance is reduced, that is, if the electrode deteriorates, there is a first problem that the electrolytic performance in the electrolytic cell is reduced. Therefore, it is required to suppress the degradation of the electrode and improve the durability of the electrode.

[0014] Furthermore, weakly basic anion exchange resins used in combination with weakly acidic cation exchange resins to neutralize water that has become acidic through softening with weakly acidic cation exchange resins have a narrower effective pH range for ion exchange reactions than strongly basic anion exchange resins in the hydroxide ion (OH) form. Consequently, neutralization to around pH 7 is difficult, and the ion exchange reaction rate near neutrality is slow.

[0015] However, when a strongly basic anion exchange resin or a weakly basic anion exchange resin having a wide effective pH range is used to neutralize acidic soft water, during neutralization, even bicarbonate ions having a low exchange order in the ion exchange reaction are easily reacted with, and a large amount of bicarbonate ions are released during regeneration of the anion exchange resin.

[0016] Therefore, as a second problem, in a regeneration system that circulates alkaline electrolyzed water, there is a problem that released bicarbonate ions reduce the efficiency of electrolysis or increase precipitates formed by the reaction of bicarbonate ions with hardness components in the electrolyzed water.

[0017] Furthermore, the weakly acidic cation exchange resin and the weakly basic anion exchange resin are regenerated respectively by the acidic electrolyzed water and the alkaline electrolyzed water generated by electrolysis. However, since the regeneration of the resins requires a certain amount of time, the continuous electrolysis time is also prolonged.

[0018] Furthermore, as the regeneration process proceeds, the hardness of the water supplied to the electrolysis increases due to hardness components (eg, calcium ions or magnesium ions) released from the soft water tank, and the concentration of carbonate ions released from the neutralization tank also increases.

[0019] Therefore, in a system in which electrolyzed water with increased concentrations of hardness components and carbonate components is electrolyzed again and reused in a regeneration process, scale (e.g., calcium carbonate) derived from hardness components and carbonate components adheres to the electrode serving as the cathode as time passes from the start of the regeneration process.

[0020] As a result, the catalyst on the electrode surface is covered with scale, which eliminates the catalytically active area and reduces electrolytic performance. In addition, since the flow of electrons between the anode and cathode is hindered, the voltage between the anode and cathode increases, which may shorten the life of the electrolytic cell.

[0021] As a conventional countermeasure against scale adhesion, a method has been used in which reverse electrolysis is performed to set the cathode to a higher potential relative to the anode than during positive electrolysis, thereby dissolving and removing scale adhered to the cathode during positive electrolysis.

[0022] However, when electrolyzing water that is prone to scale deposition, there is a third problem in that the frequency of reverse electrolysis increases, electrode degradation is accelerated, and the durability of the electrolytic cell decreases.

[0023] Conventional water softening devices are required to solve at least one of the first to third problems described above.

[0024] The present disclosure provides a water softening device capable of suppressing a decrease in electrolysis efficiency.

[0025] Furthermore, as a water softening device for solving the first problem, the water softening device disclosed herein is a water softening device that performs a softening process for softening raw water and a regeneration process for regenerating ion exchange resins degraded by the softening process. The water softening device comprises: a softening tank that softens raw water containing hardness components using a weakly acidic cation exchange resin to produce soft water in the softening process; a neutralization tank that neutralizes the acidic soft water that has passed through the softening tank using a weakly basic anion exchange resin in the softening process; and an electrolytic tank that produces electrolyzed water used in the regeneration process. Furthermore, the water softening device comprises: an adsorption amount identification unit that identifies the amount of ions adsorbed by a specific ion species in the raw water based on the ion concentration of the specific ion species in the raw water, i.e., the raw water ion concentration, and the amount of raw water passed into the softening tank; and a control unit that controls the execution of the regeneration process based on the ion adsorption amount identified by the adsorption amount identification unit. The control unit is configured to execute a replacement process when the operation time of the regeneration process reaches a reference operation time. The replacement process stops the operation of the electrolytic cell, drains the acidic electrolyzed water in the soft water tank, and introduces raw water into the soft water tank.

[0026] Furthermore, as a water softening device for solving the second problem, the present disclosure performs a softening process for softening raw water and a regeneration process for regenerating ion exchange resins degraded by the softening process. The softening device comprises: a softening tank for softening raw water using a weakly acidic cation exchange resin to produce soft water; and a neutralization tank for neutralizing the pH of the acidic soft water passing through the softening tank using an anion exchange resin. The neutralization tank contains at least two separate anion exchange resins, each of which includes a first anion exchange resin that is a weakly basic anion exchange resin and a second anion exchange resin that has a larger acid dissociation constant than the first anion exchange resin.

[0027] Furthermore, as a water softening device that solves the third problem, the disclosed water softening device includes: a control unit that controls a softening process for softening raw water containing hardness components and a regeneration process for an ion exchange resin used in the softening process; and an electrolytic cell having a first chamber and a second chamber separated from the first chamber by a diaphragm, which generates electrolyzed water used in the regeneration process. The electrolytic cell includes a first main electrode disposed in the first chamber, a first sub-electrode disposed upstream of the first main electrode, a second main electrode disposed in the second chamber, and a second sub-electrode disposed upstream of the second main electrode. The control unit is configured to execute an electrolyzed water generation mode in which the first main electrode serves as an anode and the second main electrode serves as a cathode to generate electrolyzed water; and a main electrode cleaning mode in which the application of voltage to the first and second main electrodes is stopped, electrolysis is performed with the first sub-electrode serving as a cathode and the second sub-electrode serving as an anode, thereby cleaning the second main electrode.

[0028] According to the present disclosure, it is possible to provide a water softening device that can suppress a decrease in electrolysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a figure which shows the structure of the water softening apparatus of 1st Embodiment.

[0030] Figure 2 It is a diagram showing a water softening flow path of the water softening device according to the first embodiment.

[0031] Figure 3 It is a diagram showing a regeneration circulation flow path of a softening tank and a regeneration circulation flow path of a neutralization tank in the water softening device according to the first embodiment.

[0032] Figure 4 It is a diagram showing a replacement flow path of the water softening device according to the first embodiment.

[0033] Figure 5 This is a diagram showing a regeneration flow path cleaning flow path of the water softening device according to the first embodiment.

[0034] Figure 6 This is a diagram showing an electrolytic cell cleaning flow path of the water softening device according to the first embodiment.

[0035] Figure 7 It is a diagram showing a capture unit cleaning flow path of the water softening device according to the first embodiment.

[0036] Figure 8 It is a diagram for explaining the control method of the water softening device according to the first embodiment.

[0037] Figure 9 This is a control block diagram showing the configuration of the adsorption amount identification unit of the water softening device according to the first embodiment.

[0038] Figure 10 This is a control block diagram showing the configuration of a control unit of the water softening device according to the first embodiment.

[0039] Figure 11 This is a schematic diagram for explaining determination of the number of switching times and timing from the regeneration process to the replacement process in the water softening device according to the first embodiment.

[0040] Figure 12 This is a conceptual diagram showing the structure of a water softening device according to a second embodiment.

[0041] Figure 13 It is a diagram showing a water softening flow path of a water softening device according to a second embodiment.

[0042] Figure 14 It is a diagram showing a water injection flow path and a neutralization tank regeneration flow path of a water softening device according to a second embodiment.

[0043] Figure 15 It is a diagram showing a circulation and regeneration flow path of a softening tank and a circulation and regeneration flow path of a neutralization tank in a water softening device according to a second embodiment.

[0044] Figure 16 It is a diagram showing the operating state of each component during operation of the water softening device according to the second embodiment.

[0045] Figure 17 It is a conceptual diagram showing the configuration of the water softening device according to the third to eighteenth embodiments.

[0046] Figure 18 It is a conceptual diagram showing a water softening flow path of a water softening device according to the third to eighteenth embodiments.

[0047] Figure 19 This is a conceptual diagram showing a regeneration circulation flow path of a softening tank and a regeneration circulation flow path of a neutralization tank in a water softening device according to the third to eighteenth embodiments.

[0048] Figure 20 It is a conceptual diagram showing a regeneration flow path cleaning flow path of the water softening device according to the third to eighteenth embodiments.

[0049] Figure 21 It is a conceptual diagram showing the electrolytic cell cleaning flow path of the water softening device according to the third to eighteenth embodiments.

[0050] Figure 22 It is a conceptual diagram showing a capture unit cleaning flow path of a water softening device according to the third to eighteenth embodiments.

[0051] Figure 23 It is a diagram for explaining the control method of the water softening device according to the third embodiment to the eighteenth embodiment.

[0052] Figure 24 It is a conceptual diagram showing the configuration of the electrolytic cell according to the third to eighteenth embodiments. DETAILED DESCRIPTION

[0053] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the following embodiments are examples of specific implementations of the present disclosure and do not limit the technical scope of the present disclosure.

[0054] In addition, each figure described in each embodiment is a schematic diagram, and the ratio of the size and thickness of each component in each figure does not necessarily reflect the actual dimensional ratio.

[0055] (First embodiment)

[0056] First, refer to Figure 1 A water softening device 1 according to a first embodiment of the present disclosure will be described.

[0057] Figure 1 This is a conceptual diagram showing the structure of the water softening device 1 according to the first embodiment of the present disclosure. Figure 1 , each element of the water softening device 1 is conceptually shown.

[0058] (1. Overall composition)

[0059] The water softening device 1 is a device that produces neutral soft water from raw water containing hardness components supplied from the outside. Here, neutral includes not only a pH (hydrogen ion concentration index) of 7 but also a pH of about 6 to 8.

[0060] Note that raw water refers to water (treatment target water) introduced into the device from the inlet 2, such as tap water or well water. Raw water contains hardness components (such as calcium ions and magnesium ions).

[0061] By performing a water softening treatment using the water softening device 1 , neutral soft water with reduced hardness can be obtained, and soft water can be used even in areas where the hardness of raw water is high.

[0062] Specifically, if Figure 1 As shown, the water softening device 1 includes an inlet 2, soft water tanks (a first soft water tank 3 and a second soft water tank 5), neutralization tanks (a first neutralization tank 4 and a second neutralization tank 6), a water intake 7, a regeneration device 8, a control unit 15, and an adsorption amount identification unit 55.

[0063] The water softening device 1 includes a drain port 13 , a plurality of on-off valves (on-off valves 17 to 23 ), and a plurality of flow path switching valves (flow path switching valves 24 to 27 ), the details of which will be described later.

[0064] (2. Inlet and water intake)

[0065] The inlet 2 is connected to a raw water supply source and is an opening for introducing raw water into the water softening device 1 .

[0066] The water intake port 7 is an opening for supplying the softened water flowing through the water softening device 1 to the outside of the device.

[0067] In the water softening device 1 , softened water can be taken out from the water intake port 7 using the pressure of raw water flowing in from the inlet port 2 .

[0068] In the softening process of the softening treatment in the softening device 1, raw water supplied from the outside flows through the inlet 2, the flow path 28, the first soft water tank 3, the flow path 29, the first neutralization tank 4, the flow path 30, the second soft water tank 5, the flow path 31, the second neutralization tank 6, the flow path 32 and the water intake 7 in this order, and is discharged as neutral soft water.

[0069] (3. Soft water tank)

[0070] The soft water tanks (the first soft water tank 3 and the second soft water tank 5 ) soften raw water containing hardness components by the action of the weakly acidic cation exchange resin 33 .

[0071] Specifically, the softening tank exchanges cations (calcium ions or magnesium ions)—hardness components—in circulating water (raw water) for hydrogen ions, thereby reducing the hardness of the raw water and softening it. The softening device 1 of the first embodiment includes a first softening tank 3 and a second softening tank 5 as the softening tanks.

[0072] The first soft water tank 3 softens the raw water flowing in from the inlet 2. The first soft water tank 3 includes a flow path switching valve 24. Details of the flow path switching valve will be described later.

[0073] The second soft water tank 5 softens water flowing through the first neutralization tank 4 described later. The second soft water tank 5 includes a flow path switching valve 26 .

[0074] The first soft water tank 3 and the second soft water tank 5 are filled with a weakly acidic cation exchange resin 33 .

[0075] The weakly acidic cation exchange resin 33 is an ion exchange resin having hydrogen ions at the ends of functional groups. The weakly acidic cation exchange resin 33 adsorbs cations (calcium ions and magnesium ions) as hardness components contained in the raw water flowing in, and releases hydrogen ions.

[0076] The soft water treated with the weakly acidic cation exchange resin 33 contains a large amount of hydrogen ions exchanged with hardness components. In other words, the soft water flowing out of the first soft water tank 3 and the second soft water tank 5 is acidified soft water containing a large amount of hydrogen ions (acidic soft water).

[0077] Since the functional groups of the weakly acidic cation exchange resin 33 are terminated with hydrogen ions, the weakly acidic cation exchange resin 33 can be regenerated using acidic electrolyzed water in the regeneration process described below. At this time, the cations that serve as hardness components introduced during the water softening process are released from the weakly acidic cation exchange resin 33.

[0078] There are no particular limitations on the weakly acidic cation exchange resin 33, and a general-purpose resin can be used. For example, a resin having a carboxyl group (-COOH) as an exchange group can be used. In addition, a hydrogen ion (H ＋ ) can also be metal ions, or ammonium ions (NH4 ＋ ) and other cations.

[0079] (4. Neutralization tank)

[0080] The neutralization tanks (the first neutralization tank 4 and the second neutralization tank 6 ) neutralize the pH of the soft water (acidic soft water) containing hydrogen ions discharged from the soft water tank by the action of the weakly basic anion exchange resin 34 , thereby forming neutral soft water.

[0081] Specifically, the neutralization tank adsorbs hydrogen ions and anions contained in the acidic soft water from the softening tank, thereby raising the pH of the acidic soft water to neutral soft water. The softening water device 1 of the first embodiment includes a first neutralization tank 4 and a second neutralization tank 6 as neutralization tanks.

[0082] The first neutralization tank 4 neutralizes the acidic soft water flowing through the first soft water tank 3. The first neutralization tank 4 includes a flow path switching valve 25.

[0083] The second neutralization tank 6 neutralizes the acidic soft water flowing through the second soft water tank 5. The second neutralization tank 6 includes a flow path switching valve 27.

[0084] The first neutralization tank 4 and the second neutralization tank 6 are filled with a weakly basic anion exchange resin 34 .

[0085] The weakly basic anion exchange resin 34 neutralizes hydrogen ions contained in the water passed therethrough to generate neutral water. The weakly basic anion exchange resin 34 can be regenerated using alkaline electrolyzed water in a regeneration process described later.

[0086] The weakly basic anion exchange resin 34 is not particularly limited, and a general-purpose resin can be used. For example, a free base type resin can be used.

[0087] (5. Regeneration device)

[0088] The regeneration device 8 is a device for regenerating the weakly acidic cation exchange resin 33 filled in the first soft water tank 3 and the second soft water tank 5 , and regenerating the weakly basic anion exchange resin 34 filled in the first neutralization tank 4 and the second neutralization tank 6 .

[0089] The regeneration device 8 includes an electrolytic cell 9 , a capture unit 10 , a first water supply pump 11 , and a second water supply pump 12 .

[0090] Furthermore, in the regeneration device 8, the first supply flow path 35, the second supply flow path 36, the first recovery flow path 37, and the second recovery flow path 38 are connected to the second soft water tank 5, the second neutralization tank 6, the flow path 28, and the flow path 29, respectively. Details of each flow path will be described later.

[0091] It should be noted that the first supply flow path 35, the second supply flow path 36, the first recovery flow path 37, the second recovery flow path 38, the neutralization tank bypass flow path 42 and the soft water tank bypass flow path 44 form the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 described later.

[0092] (5.1 Electrolyzer)

[0093] The electrolytic cell 9 electrolyzes the incoming water (water supplied from the inlet 2 ) using a pair of electrodes 41 (electrode 41 a and electrode 41 b ) provided therein, thereby generating and discharging acidic electrolyzed water and alkaline electrolyzed water.

[0094] More specifically, at the electrode 41 a serving as the anode during electrolysis in the regeneration step, hydrogen ions are generated by electrolysis, thereby producing acidic electrolyzed water.

[0095] Furthermore, at the electrode 41 b serving as the cathode during electrolysis in the regeneration step, hydroxide ions are generated by electrolysis, thereby producing alkaline electrolyzed water.

[0096] Then, the electrolytic tank 9 supplies acidic electrolyzed water to the first soft water tank 3 and the second soft water tank 5 via the first supply flow path 35 and the neutralization tank bypass flow path 42 , and supplies alkaline electrolyzed water to the first neutralization tank 4 and the second neutralization tank 6 via the second supply flow path 36 and the soft water tank bypass flow path 44 .

[0097] As will be described in detail later, the acidic electrolyzed water generated by the electrolytic cell 9 is used to regenerate the weakly acidic cation exchange resin 33 in the first soft water tank 3 and the second soft water tank 5, and the alkaline electrolyzed water generated by the electrolytic cell 9 is used to regenerate the weakly basic anion exchange resin 34 in the first neutralization tank 4 and the second neutralization tank 6.

[0098] The electrolytic cell 9 is configured so that the state of electricity supplied to the pair of electrodes 41 can be controlled by a control unit 15 described later.

[0099] (5.2 Water supply pump)

[0100] The first water pump 11 is used to pump acidic electrolyzed water through the soft water tank regeneration circulation flow path 39 (see FIG. Figure 3 ) equipment circulating in the market.

[0101] The first water pump 11 is provided in the first recovery flow path 37 connecting the first soft water tank 3 and the electrolytic tank 9. This arrangement is used to facilitate the circulation of acidic electrolyzed water in the soft water tank regeneration circulation flow path 39 using only the first water pump 11.

[0102] The second water pump 12 is used to pump alkaline electrolyzed water through the neutralization tank regeneration circulation path 40 (see Figure 3 ) equipment circulating in the market.

[0103] The second water pump 12 is provided in the second recovery flow path 38 connecting the first neutralization tank 4 and the electrolytic tank 9. This arrangement is used to facilitate the circulation of alkaline electrolyzed water in the neutralization tank regeneration circulation flow path 40 using only the second water pump 12.

[0104] The first water pump 11 and the second water pump 12 are connected to a control unit 15 to be described later in a wireless or wired manner so as to be communicable.

[0105] (5.3 Capture Department)

[0106] The capturing unit 10 is provided in the second supply flow path 36 that connects the electrolytic tank 9 and the second neutralization tank 6 in communication with each other.

[0107] The capturing unit 10 captures precipitates contained in the alkaline electrolyzed water fed from the electrolytic cell 9 .

[0108] The precipitate is a reaction product generated by the reaction of hardness components as cations released from the first soft water tank 3 and the second soft water tank 5 with alkaline electrolyzed water in the electrolytic tank 9 during the regeneration process.

[0109] More specifically, while water is electrolyzed in the electrolytic cell 9, hardness components (e.g., calcium ions or magnesium ions) released from the first and second soft water tanks 3 and 5 during regeneration migrate toward the cathode (electrode 41b). Since alkaline electrolyzed water is generated on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates. For example, if the hardness component is calcium ions, mixing with the alkaline electrolyzed water triggers a reaction that produces calcium carbonate or calcium hydroxide.

[0110] The precipitates derived from the hardness components are captured as precipitates in the capture section 10 provided in the second supply flow path 36. By capturing the precipitates derived from the hardness components in the capture section 10, it is possible to suppress the precipitates from flowing into the second neutralization tank 6 and accumulating.

[0111] Therefore, when the softening treatment is restarted after the regeneration treatment is completed, the hardness of the soft water sent out from the second neutralization tank 6 can be suppressed from increasing due to the ionization of the precipitates accumulated in the second neutralization tank 6 by reacting with the hydrogen ions released from the first soft water tank 3 and the second soft water tank 5.

[0112] During the regeneration process, the alkaline electrolyzed water after the precipitates derived from the hardness components are captured by the capturing unit 10 flows through the second neutralization tank 6 and the first neutralization tank 4 , and then is electrolyzed again in the electrolytic tank 9 to be supplied as alkaline electrolyzed water to regenerate the weakly basic anion exchange resin 34 .

[0113] In this case, the hardness components contained in the acidic electrolyzed water are reduced compared to a case where the capture unit 10 is not provided. That is, by capturing the precipitates with the capture unit 10, the hardness of the acidic electrolyzed water is reduced, thereby reducing the hardness components flowing into the first soft water tank 3 and the second soft water tank 5, and suppressing a decrease in the regeneration efficiency of the weakly acidic cation exchange resin 33.

[0114] It should be noted that “the hardness components react” includes not only the case where all the hardness components react, but also the state where components that do not react or components that do not exceed the solubility product are included after the reaction.

[0115] The capture unit 10 may be of any form as long as it can separate the precipitate produced by the reaction of the hardness component with the alkaline electrolyzed water. For example, a cylindrical filter, a filter layer using a granular filter material, a cyclone-type solid-liquid separator, or a hollow fiber membrane may be used.

[0116] A cartridge filter is a commonly used mechanism as the form of the capturing unit 10. The cartridge filter may be a depth filter such as a wire wound filter, a surface filter such as a pleated filter or a membrane filter, or a combination thereof.

[0117] Wire-wound filters are compatible with particle sizes ranging from 1 to 150 microns and are primarily used as pre-filters. Pleated and membrane filters are available that accommodate a wide range of particle sizes, from approximately 0.03 to 100 microns. However, when implementing the present disclosure, to reduce the likelihood of filter clogging, it is preferred to use a filter with a precision of 0.5 microns or greater (a filter corresponding to the particle size). Furthermore, to ensure adequate precipitate capture, a filter with a precision of 1.5 microns or less is preferred.

[0118] In the regeneration process described later, alkaline electrolyzed water flows through the capture part 10, and in the cleaning process, acidic electrolyzed water flows through the capture part 10. Therefore, the material of the cartridge filter is preferably a material with high corrosion resistance to acids and alkalis (for example, polypropylene).

[0119] The purpose of the granular filter material used in the filtration layer is to capture and remove hardness components. However, depending on the presence of particles with surface potential such as those adsorbed on the granular filter material or ions in the raw water, it can also remove particles with a particle size of approximately 1 to 10 microns or color components.

[0120] Granular filter media can be granular fiber filter media, such as filter sand, suitable for removing the target material. Granular filter media can be made from materials that settle in water and are hard enough to resist deformation under pressure, such as sand, anthracite, garnet, ceramic, granular activated carbon, hydrated iron oxide, or manganese sand. For example, materials with a particle size of 0.3 to 5.0 mm and a uniformity coefficient of 1.2 to 2.0 can be used.

[0121] In addition, the multilayer filtration method, which uses a mixture of filter media with different specific gravities, involves layering particles of varying sizes, starting with the smallest particle, into layers for filtration. In the multilayer filtration method, particles with a high specific gravity and small size are typically mixed with particles with a low specific gravity and large size to create a multilayer structure.

[0122] Compared to methods using a single type of filter medium, multilayer filtration is preferred because it offers higher filtration efficiency per unit volume and minimizes head loss. For example, a granular filter medium can be prepared by mixing 0.3 mm garnet, 0.6 mm sand, and 1.0 mm anthracite in a ratio of 2:1:1. The mixing ratio and particle size are preferably adjusted based on the properties of the suspended matter particles.

[0123] The capturing unit 10 includes an on-off valve 22 and a capturing unit drain port 14 .

[0124] The on-off valve 22 is provided at the bottom of the capture unit 10 and controls the drainage of the capture unit 10. By opening the on-off valve 22, the water in the capture unit 10 can be drained from the capture unit drain port 14 to the outside of the device.

[0125] The capture unit drain port 14 is an opening for draining water from the capture unit 10 to the outside of the device. By opening the on-off valve 22 provided upstream of the capture unit drain port 14, the water in the capture unit 10 can be drained from the capture unit drain port 14 to the outside of the device.

[0126] (6. On-off valve and flow path switching valve)

[0127] A plurality of on-off valves (on-off valves 17 to 23 ) are provided in each flow path, respectively, and switch between an “open” state and a “closed” state in each flow path.

[0128] The plurality of on-off valves (on-off valve 17 , on-off valve 18 , on-off valve 19 , on-off valve 21 , and on-off valve 23 ) start or stop the flow of water to each flow path by opening and closing the valves.

[0129] The on-off valve 20 and the on-off valve 22 are opened during the replacement process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process described later, and the regeneration circulating water is discharged outside the device.

[0130] A plurality of flow path switching valves (flow path switching valves 24 to 27 ) are provided in the first soft water tank 3 , the first neutralization tank 4 , the second soft water tank 5 , and the second neutralization tank 6 , respectively.

[0131] Each of the multiple flow path switching valves has three openings, the first opening is an inflow and outflow port that allows water to flow in and out, the second opening is an inflow port that functions as an inflow port rather than an outflow port, and the third opening is an outflow port that functions as an outflow port rather than an inflow port.

[0132] The inlet and outlet of the plurality of flow path switching valves are always "open", and depending on the water flow direction, when either the inlet or outlet is "open", the other outlet is "closed".

[0133] By providing the flow path switching valves 24 to 27 , the number of on-off valves required for each flow path in the water softening device 1 can be reduced, and the cost of the water softening device 1 can be reduced.

[0134] Furthermore, the plurality of on-off valves (on-off valves 17 to 23 ) and the plurality of flow path switching valves (flow path switching valves 24 to 27 ) are communicably connected to a control unit 15 described later via wireless or wired communication.

[0135] (7. Adsorption Amount Identification Department)

[0136] In the softening process described later, when raw water is passed through the softening tank, cations (e.g., calcium ions and magnesium ions) contained in the raw water, which are hardness components, are adsorbed by the weakly acidic cation exchange resin 33. Hydrogen ions, exchanged for the hardness components, are released into the water. As a result, the raw water containing hardness components becomes acidified soft water containing hydrogen ions.

[0137] When the acidic soft water is further passed into the neutralization tank, hydrogen ions are adsorbed on the weakly basic anion exchange resin 34 together with anions (for example, chloride ions, sulfate ions, nitrate ions, carbonate ions, etc.).

[0138] The adsorption amount identification unit 55 identifies the adsorption amount of a specific ion species adsorbed to the weakly basic anion exchange resin 34 during a water softening step described later.

[0139] It should be noted that specific ion species refer to anions (eg, chloride ions, sulfate ions, or nitrate ions) that affect electrode degradation during the regeneration process. In this embodiment, chloride ions are representatively described as specific ion species.

[0140] That is, the adsorption amount evaluation unit 55 calculates the amount of chloride ions adsorbed by the weakly basic anion exchange resin 34 in the neutralization tank during the water softening step.

[0141] The adsorption amount identification unit 55 is provided on the downstream side of the second neutralization tank 6 and the upstream side of the water intake port 7 , and is provided in the flow path 32 in the first embodiment.

[0142] Reference Figure 9 The configuration and control of the adsorption amount identification unit 55 according to the first embodiment of the present disclosure will be described.

[0143] Figure 9 This is a control block diagram showing the configuration of the adsorption amount identification unit 55 of the water softening device 1 according to the first embodiment.

[0144] The adsorption amount evaluation unit 55 includes a flow rate measurement unit 60 , a raw water quality recording unit 61 , and an adsorption amount calculation unit 62 .

[0145] (7.1 Flow rate measurement unit)

[0146] The flow rate measuring unit 60 measures the flow rate of the neutral soft water flowing out of the second neutralization tank 6 .

[0147] The flow rate measuring unit 60 is connected to an adsorption amount calculating unit 62 described later in a wireless or wired manner. Information on the flow rate of soft water detected by the flow rate measuring unit 60 is used as an input signal to the adsorption amount calculating unit 62.

[0148] The flow rate measuring unit 60 may be any detector that measures the flow rate of water, and a general-purpose detector such as an impeller type or an ultrasonic type may be used.

[0149] (7.2 Raw Water Quality Recording Section)

[0150] The raw water quality recording unit 61 records the chloride ion concentration of the raw water flowing into the water softening device 1. As the chloride ion concentration of the raw water, a value corresponding to the region where the water softening device 1 is used or a previously measured chloride ion concentration value can be input.

[0151] Alternatively, a device capable of measuring the chloride ion concentration of raw water may be provided on the downstream side of the inlet 2 , that is, in the flow path 28 , and the raw water quality recording unit 61 may record the value measured by the device as the chloride ion concentration of raw water.

[0152] The raw water quality recording unit 61 is wirelessly or wiredly connected to the adsorption amount calculation unit 62 and the control unit 15 . The recorded chloride ion concentration of the raw water is used as an input signal to the adsorption amount calculation unit 62 and the control unit 15 .

[0153] (7.3 Adsorption Calculation Section)

[0154] The adsorption amount calculation unit 62 calculates the amount of chloride ions adsorbed to the weakly basic anion exchange resin 34 in the water softening step as the chloride ion adsorption amount.

[0155] Specifically, the adsorption amount calculation unit 62 receives the flow rate of the neutral soft water flowing out of the second neutralization tank 6 detected by the flow rate measurement unit 60. In addition, the adsorption amount calculation unit 62 receives the chloride ion concentration of the raw water recorded in the raw water quality recording unit 61.

[0156] The adsorption amount calculation unit 62 then calculates the amount of chloride ions adsorbed to the weakly basic anion exchange resin 34 based on the received flow rate of neutral soft water and the chloride ion concentration of the raw water using the following formula (1). The calculated amount of chloride ions adsorbed is used as an input signal to the control unit 15.

[0157] Chloride ion adsorption capacity (moL) = chloride ion concentration of raw water (moL / L) × chloride ion adsorption rate (%) × flow rate (L)……(1)

[0158] The chloride ion adsorption rate here is a value obtained in advance through experiments using the flow rate as a parameter with respect to the chloride ion concentration of the raw water.

[0159] Specifically, the adsorption rate of chloride ions onto the weakly basic anion exchange resin 34 decreases linearly with increasing flow rate, as adsorption efficiency decreases. Therefore, the amount of chloride ion adsorption per unit flow rate decreases linearly based on experimentally acquired data. Therefore, the chloride ion adsorption rate can be predicted based on the flow rate and the chloride ion concentration of the raw water.

[0160] For example, when 200 L of raw water having a chloride ion concentration of 1 mmol / L is passed through a weakly basic anion exchange resin and the chloride ion adsorption rate is 30%, the chloride ion adsorption amount is 1 mmol / L×50%×200 L=100 mmol.

[0161] (8. Drain outlet)

[0162] Return to Figure 1The drain port 13 is an opening provided at the end of the drain flow path 54 and is an opening for discharging water in the device to the outside of the device during the regeneration path cleaning process and the electrolytic cell cleaning process.

[0163] An on-off valve 20 is provided upstream of the drain port 13 , and water can be discharged from the drain port 13 by opening the on-off valve 20 .

[0164] (9. Control Department)

[0165] The control unit 15 controls the execution of each process of the water softening process, the regeneration process, the replacement process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process, and controls switching between the processes.

[0166] Specifically, the control of switching between each process means that the control unit 15 controls the switching from the softening process to the regeneration process, the switching from the regeneration process to the regeneration flow path cleaning process, the switching from the regeneration process to the replacement process, the switching from the replacement process to the regeneration process, the switching from the regeneration flow path cleaning process to the electrolytic cell cleaning process, the switching from the electrolytic cell cleaning process to the capture part cleaning process, and the switching from the capture part cleaning process to the softening process.

[0167] Furthermore, the control unit 15 controls the on-off valve 20 and the on-off valve 22 to control drainage during the replacement process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process.

[0168] Furthermore, the control unit 15 controls the flow path switching valves 24 to 27 , the on-off valve 17 , the on-off valve 18 , the on-off valve 19 , the on-off valve 21 , and the on-off valve 23 to switch the flow paths.

[0169] The control unit 15 is connected to the adsorption amount identification unit 55 via wired or wireless communication, and calculates the reference operation time based on the identified ion adsorption amount calculated by the adsorption amount identification unit 55 and the current value of the electrolytic cell 9 .

[0170] In order to reduce the chloride ion concentration, the control unit 15 stops the operation of the electrolytic cell 9 when the operation time of the regeneration process reaches the reference operation time, and switches from the regeneration process to the replacement process.

[0171] It should be noted that when the control unit 15 implements multiple replacement processes within the reference operating time, it determines the number of implementation times and implementation timings of the replacement processes performed in the regeneration process based on the chloride ion concentration reference value, the chloride ion concentration of the raw water, the total regeneration operating time, the chloride ion adsorption amount and the reference operating time.

[0172] Furthermore, the control unit 15 can reduce the average value of the chloride ion concentration of the acidic electrolyzed water to below the chloride ion concentration reference value during the total regeneration operation time by switching from the regeneration process to the replacement process at a predetermined timing.

[0173] It should be noted that the chloride ion concentration reference value refers to the average value of the chloride ion concentration of the acidic electrolyzed water from the start of operation of the electrolytic cell 9 to the time when the electrodes 41 of the electrolytic cell 9 need to be replaced, i.e., the electrolytic cell replacement time, during the regeneration process.

[0174] For example, in this embodiment, when the electrolytic cell replacement time is 5000 hours, the chloride ion concentration reference value is 4 mmol / L. This means that when the chloride ion concentration of the electrolyzed water passed into the electrolytic cell 9 is 4 mmol / L, when the electrolytic cell 9 is operated for 5000 hours, the electrodes 41 of the electrolytic cell 9 will deteriorate to the extent that the electrolytic cell 9 needs to be replaced.

[0175] In other words, the chloride ion concentration reference value is the chloride ion concentration at which, when the electrolytic cell 9 is operated at this chloride ion concentration, the electrolytic cell 9 needs to be replaced when the electrolytic cell replacement time is reached. It should be noted that the electrolytic cell replacement time is a value predetermined based on the performance of the electrolytic cell 9.

[0176] Reference Figure 10 The configuration of the control unit 15 will be described.

[0177] Figure 10 This is a control block diagram showing the configuration of the control unit 15 of the water softening device 1 according to the first embodiment.

[0178] The control unit 15 includes a hydroxide ion generation amount calculation unit 56 , a reference operation time calculation unit 57 , a recording unit 58 , and a number determination unit 59 .

[0179] (9.1 Calculation of Hydroxide Ion Generation)

[0180] The hydroxide ion generation amount calculation unit 56 calculates the amount of hydroxide ions generated per unit time by electrolysis in the electrolytic cell 9 in the regeneration step as the hydroxide ion generation amount per unit time.

[0181] The amount of hydroxide ion generated per unit time (moL / h) in the electrolytic cell 9 is derived from the current value (A=C / seC), the Faraday constant (C / moL), and the generation efficiency (%). Specifically, it is derived using the following formula (2).

[0182] Hydroxide ion generation per unit time (moL / h) = current value (A = C / seC) × generation efficiency (%) × 3600 ÷ Faraday constant (C / moL) ... (2)

[0183] The calculated hydroxide ion generation amount per unit time is output to the reference operation time calculation unit 57 described below and used for calculation of the reference operation time.

[0184] (9.2 Standard operating time calculation section)

[0185] The reference operating time calculation unit 57 calculates the time from the start of the regeneration process to the time when the chloride ions are substantially completely desorbed from the weakly basic anion exchange resin 34 as the reference operating time based on the hydroxide ion generation amount per unit time calculated by the hydroxide ion generation amount calculation unit 56 and the chloride ion adsorption amount calculated by the adsorption amount identification unit 55.

[0186] That is, the reference operation time is the time when the amount of chloride ions in the electrolyzed water reaches a maximum. It should be noted that "substantially all" includes not only 100% of the adsorbed chloride ions but also, for example, approximately 95%.

[0187] If the regeneration process is continued as it is when the reference operating time or longer has elapsed since the start of the regeneration process, electrolysis in the electrolytic cell 9 will proceed with a high chloride ion concentration, thus accelerating deterioration of the electrode 41 .

[0188] The reason for this is explained below. The chloride ions released from the weakly basic anion exchange resin 34 migrate from the cathode side to the anode side due to the electrolysis of water in the electrolytic cell 9. Therefore, for the anode using a platinum-based electrode catalyst material, PT+4CL occurs. - ⇒[PTCL4] 2- +2e - This reaction occurs when platinum reacts with chloride ions, causing dissolution and desorption. The higher the chloride ion concentration, the more likely platinum dissolution occurs, resulting in a decrease in the amount of electrode catalyst. Consequently, the electrolytic performance of electrolytic cell 9 deteriorates.

[0189] In order to suppress such deterioration of the electrolytic cell 9 , a replacement process is performed when the regeneration operation time reaches the reference operation time.

[0190] In the replacement process, the operation of the electrolytic cell 9 is stopped, the acidic electrolyzed water with a high chloride ion concentration in the soft water tank is drained, and raw water is introduced into the soft water tank. This can reduce the chloride ion concentration of the acidic electrolyzed water to that of the raw water.

[0191] Furthermore, by implementing the replacement process, during the regeneration operation after the reference operating time has elapsed, the weakly basic anion exchange resin 34 is regenerated. Therefore, the amount of chloride ions adsorbed on the weakly basic anion exchange resin 34 is small, and thus the electrolytic cell 9 can be operated at a chloride ion concentration substantially consistent with the raw water. Consequently, deterioration of the anode of the electrolytic cell 9 can be suppressed.

[0192] The following describes a method for calculating the reference operating time.

[0193] During the regeneration process, the weakly basic anion exchange resin 34 reacts with hydroxide ions in the incoming alkaline electrolyzed water, causing hydrogen ions and chloride ions to be removed from the weakly basic anion exchange resin 34. Chloride ions have lower selectivity for the weakly basic anion exchange resin 34 than other anions such as sulfate and nitrate ions. Therefore, during the regeneration process, an exchange reaction with hydroxide ions occurs more readily. Consequently, chloride ions preferentially remove from the weakly basic anion exchange resin 34 compared to other anions such as sulfate and nitrate ions. Consequently, chloride ions are more likely to be removed immediately after the regeneration process begins.

[0194] At the beginning of the regeneration process, most of the hydroxide ions in the flowing alkaline electrolyzed water are consumed by the regeneration of chloride ions. Therefore, the regeneration efficiency of chloride ions is high according to the rate at which chloride ions are desorbed from the weakly basic anion exchange resin 34 .

[0195] As the regeneration process progresses, the amount of chloride ions adsorbed on the weakly basic anion exchange resin 34 gradually decreases. Consequently, the regeneration efficiency of chloride ions decreases. Consequently, the regeneration efficiency of chloride ions varies depending on the time elapsed from the start of regeneration. Therefore, the time elapsed from the start of the regeneration process, i.e., the regeneration operation time, is calculated in advance through experiments and used as a parameter for calculating the reference operation time.

[0196] The reference operating time can be calculated by the following formula (3).

[0197] Reference operating time (h) = chloride ion adsorption capacity (moL) ÷ chloride ion regeneration efficiency (%) ÷ hydroxide ion generation per unit time (moL / h)……(3)

[0198] (9.3 Records Department)

[0199] The recording unit 58 records data used in the calculation of the number of times determining unit 59 and sends the data to the number of times determining unit 59 .

[0200] Specifically, the recording unit 58 records the chloride ion concentration reference value, the chloride ion concentration of the raw water, the chloride ion adsorption amount, and the total regeneration operation time.

[0201] The raw water chloride concentration is transmitted from the raw water quality recording unit 61 of the adsorption amount evaluation unit 55. The chloride adsorption amount is transmitted from the adsorption amount calculation unit 62 of the adsorption amount evaluation unit 55. The chloride concentration reference value and the total regeneration operation time are recorded in the recording unit 58 in advance.

[0202] If the regeneration process is continued while the average chloride ion concentration in the acidic electrolyzed water is greater than the chloride ion concentration reference value, even if it is not yet time to replace the electrolytic cell, deterioration of the electrolytic cell 9 may cause the water electrolysis efficiency to decrease and electrolysis to become inoperable. In other words, regeneration of the weakly acidic cation exchange resin 33 and the weakly basic anion exchange resin 34 may not be completed. Therefore, it is preferable to perform the regeneration process while maintaining the average chloride ion concentration below the chloride ion concentration reference value.

[0203] As described above, by executing the replacement process when the reference operation time is reached, the regeneration process can be continuously performed after the reference operation time in a state where the chloride ion concentration of the electrolyzed water is substantially equal to the chloride ion concentration of the raw water.

[0204] However, the chloride ion concentration in the acidic electrolyzed water reaches its maximum value during the period from the start of the regeneration process to the reference operating time. Therefore, if the average chloride ion concentration in the acidic electrolyzed water is calculated based on the total regeneration operating time, the average chloride ion concentration may exceed the reference chloride ion concentration value. In this case, multiple replacement processes will need to be performed before the reference operating time is reached.

[0205] Hereinafter, a method for calculating the number of times and timings of performing the replacement process when the replacement process is performed multiple times will be described.

[0206] (9.4 Determination of the number of times)

[0207] The number determination unit 59 determines the number and timing of switching from the regeneration process to the replacement process within the reference operation time based on the chloride ion concentration reference value received from the recording unit 58, the chloride ion concentration of the raw water, the chloride ion adsorption amount, the total regeneration operation time, and the reference operation time calculated by the reference operation time calculation unit 57, so as to reduce the average chloride ion concentration to below the chloride ion concentration reference value that meets the specified electrolytic cell replacement time.

[0208] use Figure 11 The calculation of the number and timing of process replacement will be described.

[0209] Figure 11 This is a schematic diagram for explaining determination of the number of times and timing of switching the water softening device 1 according to the first embodiment from the regeneration process to the replacement process. Figure 11 (a) is a schematic diagram showing changes in the chloride ion concentration in the acidic electrolyzed water when the replacement process is performed three times. Figure 11 (b) is a graph showing the correlation between the number of replacements and the average chloride ion concentration.

[0210] like Figure 11 As shown in (a), in this embodiment, the desorption rate of chloride ions from the weakly basic anion exchange resin 34 per unit time is constant, and the time interval from the replacement step to the next replacement step is constant.

[0211] After time T1 has passed since the start of the regeneration process, the chloride ion concentration in the acidic electrolyzed water reaches C1. When the first replacement process is performed at the timing when the chloride ion concentration reaches C1 (time T1), the chloride ion concentration decreases from C1 to C2, which is the chloride ion concentration of the raw water.

[0212] Next, at time T2, which is the same time as time T1 (i.e., T1-0 = T2-T1), the chloride ion concentration rises to C1+C2. Then, when the second replacement step is performed at this time (time T2), the chloride ion concentration decreases from C1+C2 to C2.

[0213] Therefore, the change in chloride ion concentration caused by the implementation of the replacement process can be as follows Figure 11 Based on (a). Figure 11 The calculation formula for calculating the average value of the chloride ion concentration is derived from the area of ​​the oblique line of (a) and the total regeneration operation time.

[0214] When the average chloride ion concentration is Y, the chloride ion adsorption amount is B, the chloride ion concentration of the raw water is C, the reference operation time is A, the total regeneration operation time is D, and the number of replacements is X, the relationship between the average chloride ion concentration Y and the number of replacements X is expressed as the following formula (4).

[0215] Y=[C×(DA / X)+(A / X)×(B / X) / 2×X] / D=C+(A×B-2×A×B) / (2×X×D)……(4)

[0216] That is, Figure 11 As shown in (b), the average chloride ion concentration Y (vertical axis) and the number of replacements X (horizontal axis) show a negative correlation. Increasing the number of replacements X further reduces the average chloride ion concentration Y, but the time required for the replacement process and the amount of raw water required for the replacement process increase.

[0217] Therefore, the minimum value of the number of replacements X at which the average chloride ion concentration becomes equal to or less than the chloride ion concentration reference value is taken as the actual number of replacements X1. Note that the timing of performing the replacement step is preferably set to A×n / X1 (n=1, 2, ..., X1).

[0218] (10.Flow path)

[0219] Return to Figure 1 Flow path 53 connects the inlet 2 and the water intake 7, and is provided with an on-off valve 18. When any of the regeneration process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process is performed using flow path 53, the user of the water softening device 1 can obtain raw water from the water intake 7.

[0220] (11. Water softening flow path)

[0221] Reference Figure 2 The softening flow path 43 formed during the water softening step of the water softening device 1 will be described.

[0222] Figure 2 It is a diagram showing the water softening flow path 43 of the water softening device 1 .

[0223] Softening flow path 43 ( Figure 2 The oblique line arrows (indicated by the arrows in FIG) are the flow paths for softening the raw water. The raw water flowing through the softening flow path 43 becomes neutral soft water, and the neutral soft water is discharged from the water intake port 7 to the outside of the device.

[0224] The softening flow path 43 is formed by the inlet 2 , the flow path 28 , the first softening tank 3 , the flow path 29 , the first neutralization tank 4 , the flow path 30 , the second softening tank 5 , the flow path 31 , the second neutralization tank 6 , the flow path 32 , and the water intake 7 .

[0225] The flow path 28 is a flow path connected from the inlet 2 to the first soft water tank 3. That is, the flow path 28 is a flow path that guides raw water containing hardness components from the inlet 2 to the first soft water tank 3.

[0226] The flow path 29 is a flow path connecting the first soft water tank 3 to the first neutralization tank 4. That is, the flow path 29 is a flow path that guides the water softened in the first soft water tank 3 to the first neutralization tank 4.

[0227] The flow path 30 is a flow path connected from the first neutralization tank 4 to the second soft water tank 5. That is, the flow path 30 is a flow path that guides the water neutralized in the first neutralization tank 4 to the second soft water tank 5.

[0228] The flow path 31 is a flow path connected from the second soft water tank 5 to the second neutralization tank 6. That is, the flow path 31 is a flow path that guides the water softened in the second soft water tank 5 to the second neutralization tank 6.

[0229] The flow path 32 is a flow path connected from the second neutralization tank 6 to the water intake port 7. That is, the flow path 32 is a flow path that guides softened raw water from the second neutralization tank 6 to the water intake port 7.

[0230] like Figure 2As shown, an on-off valve 19 is provided in the flow path 28 downstream of the inlet 2 and upstream of the first soft water tank 3. Furthermore, an on-off valve 18 is provided in the flow path 53. By closing the on-off valve 18 and opening the on-off valve 19, the first soft water tank 3 and the inlet 2 are connected to each other.

[0231] In addition, the flow path switching valve 24 is switched to connect the first soft water tank 3 with the first neutralization tank 4, the flow path switching valve 25 is switched to connect the first neutralization tank 4 with the second soft water tank 5, the flow path switching valve 26 is switched to connect the second soft water tank 5 with the second neutralization tank 6, and the flow path switching valve 27 is switched to connect the second neutralization tank 6 with the water intake 7.

[0232] Thus, a softening flow path 43 is formed that communicates from the inlet 2 to the flow path 28, the first softening tank 3, the flow path 29, the first neutralization tank 4, the flow path 30, the second softening tank 5, the flow path 31, the second neutralization tank 6, the flow path 32 and the water intake 7.

[0233] It should be noted that, at this time, the on-off valve 17 , the on-off valve 20 , the on-off valve 21 , and the on-off valve 23 are closed.

[0234] (12. Regeneration circulation flow path)

[0235] Next, refer to Figure 3 The softening tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 formed during the regeneration process of the water softening device 1 will be described.

[0236] Figure 3 It is a diagram showing the softening tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 of the water softening device 1.

[0237] First, the soft water tank regeneration circulation flow path 39 will be described.

[0238] The soft water tank regeneration circulation flow path 39 is a flow path for regenerating the first soft water tank 3 and the second soft water tank 5 by circulating acidic electrolyzed water during the regeneration process. Figure 3 Indicated by (white arrows) is a flow path in which water delivered by the first water delivery pump 11 circulates through the electrolytic tank 9 , the second soft water tank 5 , and the first soft water tank 3 and returns to the electrolytic tank 9 .

[0239] Specifically, the soft water tank regeneration circulation flow path 39 is composed of the first supply flow path 35 connecting the electrolytic tank 9 , the second soft water tank 5 , the first soft water tank 3 and the first water supply pump 11 , the neutralization tank bypass flow path 42 and the first recovery flow path 37 .

[0240] The first supply flow path 35 is a flow path that communicates from the downstream side of the electrolytic tank 9 to the downstream side of the second soft water tank 5 , and is a flow path for supplying acidic electrolyzed water from the electrolytic tank 9 to the second soft water tank 5 .

[0241] The neutralization tank bypass flow path 42 is a flow path that bypasses the first neutralization tank 4 and is connected from the upstream side of the second soft water tank 5 to the downstream side of the first soft water tank 3 . It is a flow path for supplying acidic electrolyzed water from the second soft water tank 5 to the first soft water tank 3 .

[0242] The first recovery flow path 37 is a flow path connected from the upstream side of the first soft water tank 3 to the electrolytic tank 9 , and is a flow path for recovering the acidic electrolyzed water containing hardness components that has passed through the first soft water tank 3 and the second soft water tank 5 to the electrolytic tank 9 .

[0243] The first water supply pump 11 is provided in the first recovery flow path 37. In addition, the on-off valve 17 is provided in the first recovery flow path 37. The on-off valve 17 is opened and closed when switching to the replacement process described later.

[0244] Thus, the soft water tank regeneration circulation flow path 39 is a flow path that introduces the acidic electrolyzed water sent out from the electrolytic tank 9 into the first soft water tank 3 and the second soft water tank 5 from their respective downstream sides, and causes it to flow out from the upstream side of each soft water tank where the adsorption amount of hardness components is greater than that of the downstream side.

[0245] In addition, the "downstream side (or upstream side)" in the softening tank and the neutralization tank means the downstream side (or upstream side) in the flow path during the softening treatment.

[0246] Next, the neutralization tank regeneration circulation flow path 40 will be described.

[0247] The neutralization tank regeneration circulation flow path 40 is a flow path for regenerating the first neutralization tank 4 and the second neutralization tank 6 by circulating alkaline electrolyzed water during the regeneration process. Figure 3 Indicated by (black arrows) is a flow path in which water delivered by the second water delivery pump 12 circulates through the electrolytic tank 9 , the second neutralization tank 6 , and the first neutralization tank 4 and returns to the electrolytic tank 9 .

[0248] Specifically, the neutralization tank regeneration circulation flow path 40 is composed of the second supply flow path 36 connecting the electrolytic tank 9, the second neutralization tank 6, the first neutralization tank 4 and the second water supply pump 12, the soft water tank bypass flow path 44 and the second recovery flow path 38.

[0249] The second supply flow path 36 is a flow path that communicates from the downstream side of the electrolytic tank 9 to the downstream side of the second neutralization tank 6 , and is a flow path for supplying alkaline electrolyzed water from the electrolytic tank 9 to the second neutralization tank 6 .

[0250] The second supply flow path 36 is provided with the capture unit 10 , the on-off valve 21 , and the on-off valve 23 .

[0251] The soft water tank bypass flow path 44 is a flow path that bypasses the second soft water tank 5 and communicates from the upstream side of the second neutralization tank 6 to the downstream side of the first neutralization tank 4 , and is a flow path for supplying alkaline electrolyzed water from the second neutralization tank 6 to the first neutralization tank 4 .

[0252] The second recovery flow path 38 is a flow path that communicates with the electrolytic tank 9 from the upstream side of the first neutralization tank 4 , and is a flow path that recovers the alkaline electrolyzed water that has passed through the first neutralization tank 4 and the second neutralization tank 6 to the electrolytic tank 9 .

[0253] The second water supply pump 12 is provided in the second recovery flow path 38 .

[0254] (13. Replacement of flow path)

[0255] Next, refer to Figure 4 The replacement flow path 70 formed during the replacement process of the water softening device 1 will be described.

[0256] Figure 4 It is a diagram showing the replacement flow path 70 of the water softening device 1 .

[0257] The replacement flow path 70 is a flow path for replacing the acidic electrolyzed water containing high chloride ions in the first soft water tank 3 and the second soft water tank 5 with raw water during a replacement step described later.

[0258] like Figure 4 As shown by (black arrows), the replacement flow path 70 is composed of flow paths that are connected from the inlet 2 to the first soft water tank 3 , the second soft water tank 5 , the on-off valve 20 , and the drain port 13 .

[0259] Specifically, the replacement flow path 70 (second drain flow path 47 ) is a flow path that allows the raw water flowing in from the inlet 2 to flow through the flow path 28 , the first soft water tank 3 , the neutralization tank bypass flow path 42 , the second soft water tank 5 , the first supply flow path 35 , the drain flow path 54 , the on-off valve 20 , and the drain outlet 13 in this order.

[0260] (14. Regeneration flow path and cleaning flow path)

[0261] Next, refer to Figure 5 The regeneration flow path cleaning flow path 45 formed during the regeneration flow path cleaning step of the water softening device 1 will be described.

[0262] Figure 5 It is a diagram showing the regeneration flow path cleaning flow path 45 of the water softening device 1 .

[0263] The regeneration flow path cleaning flow path 45 is a flow path for discharging high-hardness water remaining in the flow path to the outside of the apparatus without flowing into the first neutralization tank 4 and the second neutralization tank 6 during a regeneration flow path cleaning step described later.

[0264] The regeneration flow path cleaning flow path 45 is configured to include a first drain flow path 46 and a second drain flow path 47 .

[0265] like Figure 5 As shown by (white arrows), the first drain flow path 46 is composed of flow paths connecting the first water pump 11 , the electrolytic cell 9 , the on-off valve 20 , and the drain port 13 from the inlet 2 .

[0266] Specifically, the first drain flow path 46 allows the raw water flowing in from the inlet 2 to flow through the flow path 28 , the first recovery flow path 37 , the first water pump 11 , the electrolytic cell 9 , the drain flow path 54 , the on-off valve 20 , and the drain port 13 in this order.

[0267] The drain flow path 54 is connected to the first supply flow path 35 at one end and to the drain port 13 at the other end. An on-off valve 20 is provided in the drain flow path 54. By opening the on-off valve 20, water in the flow path can be drained out of the device, and by closing the on-off valve 20, drainage from the drain port 13 can be stopped.

[0268] In addition, during the regeneration flow path cleaning step described later, the replacement flow path 70 is used as the second drain flow path 47 of the regeneration flow path cleaning flow path 45 .

[0269] Note that it is preferable to control the flow rate of water flowing through the second drain flow path 47 to be larger than the flow rate of water flowing through the first drain flow path 46 .

[0270] This allows high-hardness water in the second drainage channel, which is the channel including the softening tank used in the water softening process, to be preferentially replaced with raw water. Therefore, the influence of high-hardness water at the start of the water softening process can be suppressed.

[0271] (15. Electrolytic cell cleaning flow path)

[0272] Next, refer to Figure 6 The electrolytic cell cleaning flow path 49 formed during the electrolytic cell cleaning step of the water softening device 1 will be described.

[0273] Figure 6 This is a diagram showing the electrolytic cell cleaning flow path 49 of the water softening device 1 .

[0274] The electrolytic tank cleaning flow path 49 is a flow path for removing precipitates caused by hardness components in the electrolytic tank 9 and the neutralization tank regeneration circulation flow path 40 during the electrolytic tank cleaning step described later.

[0275] The electrolytic cell cleaning flow path 49 is configured to include the first drain flow path 46 and the third drain flow path 50 described above.

[0276] like Figure 6As shown by the black arrows, the third drainage flow path 50 is composed of the flow paths connected from the inlet 2 to the first soft water tank 3, the second water pump 12, the electrolytic cell 9, the on-off valve 21, the capture unit 10, the on-off valve 22 and the capture unit drain port 14.

[0277] Specifically, the third drainage flow path 50 is a flow path that allows the raw water flowing in from the inlet 2 to flow through the flow path 28, the first soft water tank 3, the second recovery flow path 38, the second water supply pump 12, the electrolytic cell 9, the second supply flow path 36, the switch valve 21, the capture part 10 and the switch valve 22 in sequence, and is discharged to the outside of the device from the capture part drain port 14.

[0278] More specifically, in the third drain flow path 50, raw water flowing in from the inlet 2 flows through the flow path 28 into the first soft water tank 3, thereby forming acidic soft water. The generated acidic soft water then flows through the second recovery flow path 38 and into the electrolytic cell 9 via the second water supply pump 12. The acidic soft water then flows through the second supply flow path 36, sequentially through the on-off valve 21, the capture unit 10, and the on-off valve 22. The precipitate in the capture unit 10 is dissolved in the acidic soft water, and then discharged from the capture unit drain port 14 to the outside of the device.

[0279] (16. Capture unit cleaning flow path)

[0280] Next, refer to Figure 7 The capturing unit cleaning flow path 51 (fourth drain flow path 52 ) formed during the capturing unit cleaning step of the water softening device 1 will be described.

[0281] Figure 7 It is a diagram showing the capture unit cleaning flow path 51 of the water softening device 1 .

[0282] The capturing portion cleaning flow path 51 is a flow path for removing precipitates derived from hardness components precipitated in the capturing portion 10 during a capturing portion cleaning step described later. The capturing portion cleaning flow path 51 includes a fourth drain flow path 52 .

[0283] like Figure 7 As shown, the capture part cleaning flow path 51 is composed of flow paths connected from the inlet 2 to the first soft water tank 3 , the first neutralization tank 4 , the second soft water tank 5 , the second neutralization tank 6 , the capture part 10 and the capture part drain port 14 .

[0284] Specifically, the capture section cleaning flow path 51 is a flow path that allows the raw water flowing in from the inlet 2 to flow in sequence through the flow path 28, the first soft water tank 3, the flow path 29, the first neutralization tank 4, the flow path 30, the second soft water tank 5, the flow path 31, the second neutralization tank 6, the second supply flow path 36, the switch valve 23, the capture section 10 and the switch valve 22, and is discharged from the capture section drain port 14 to the outside of the device.

[0285] The above is the structure of the water softening device 1.

[0286] Next, the operation of the water softening device 1 will be described.

[0287] (17. Water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process and capture unit cleaning process)

[0288] Next, refer to Figure 8 The water softening step, the regeneration step, the regeneration flow path cleaning step, the electrolytic cell cleaning step, and the capturing portion cleaning step of the water softening device 1 will be described.

[0289] Figure 8 The diagrams show the states of the components in the water softening device 1 during each process.

[0290] In the water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process and capture part cleaning process, as Figure 8 As shown, the control unit 15 switches the on-off valves 17 to 23 , the flow path switching valves 24 to 27 , the electrode 41 of the electrolytic cell 9 , the first water supply pump 11 , and the second water supply pump 12 to control the respective flow states.

[0291] Here, Figure 8 The "ON" column indicates that the corresponding switch valve is "open", the electrode 41 is energized, and the corresponding water pump is operating. The blank column indicates that the corresponding switch valve is "closed", the electrode 41 is not energized, and the corresponding water pump is stopped.

[0292] in addition, Figure 8 The phrase "from (component A's number) to (component B's number)" indicates that the corresponding flow path switching valve is connected to the flow path in the direction of water flow from component A to component B. For example, flow path switching valve 24 in the water softening process connects the flow paths so that water can flow from flow path 28 to flow path 29.

[0293] in addition, Figure 8 The phrase "toward (number of component C)" indicates that the corresponding flow path switching valve is connected to the flow path in a direction that could potentially supply water to component C. In this case, although the flow path is connected, the environment is such that water is unlikely to flow into or out of the soft water tank or neutralization tank in which the corresponding flow path switching valve is installed, and therefore, water is unlikely to be supplied from the corresponding flow path switching valve.

[0294] (17.1 Water Softening Process)

[0295] First, refer to Figure 2 and Figure 8 The column “during water softening” explains the operation of the water softening device 1 when performing the water softening process.

[0296] In the water softening device 1, as Figure 8 As shown, in the water softening process, the on-off valve 19 provided in the flow path 28 is opened in a state where the on-off valve 17 and the on-off valve 18 are closed. Thus, raw water containing hardness components flows in from the outside.

[0297] Raw water flowing in from the outside does not flow into the electrolytic cell 9 but flows sequentially through the first softening tank 3 , the first neutralization tank 4 , the second softening tank 5 , and the second neutralization tank 6 . Therefore, in the water softening device 1 , softened water (neutral soft water) can be taken out from the water intake 7 .

[0298] At this time, the flow path switching valve 24 becomes a connection state capable of supplying water from the flow path 28 to the flow path 29, the flow path switching valve 25 becomes a connection state capable of supplying water from the flow path 29 to the flow path 30, the flow path switching valve 26 becomes a connection state capable of supplying water from the flow path 30 to the flow path 31, and the flow path switching valve 27 becomes a connection state capable of supplying water from the flow path 31 to the flow path 32.

[0299] The on-off valves 20 to 23 are all in the closed state.

[0300] Furthermore, the operation of the electrodes 41 of the electrolytic cell 9 , the first water pump 11 , and the second water pump 12 is also stopped.

[0301] Specifically, if Figure 2 As shown, in the water softening process, raw water is supplied from the inlet 2 through the flow path 28 to the first soft water tank 3 using the pressure of raw water flowing in from the outside. The raw water supplied to the first soft water tank 3 then flows through the weakly acidic cation exchange resin 33 provided in the first soft water tank 3.

[0302] At this point, the cations in the raw water, which are hardness components, are adsorbed by the weakly acidic cation exchange resin 33, releasing hydrogen ions (ion exchange). This removes cations from the raw water, softening it. Because the softened water contains a large amount of hydrogen ions released in exchange for hardness components, it becomes acidic, resulting in a low pH (first soft water).

[0303] Here, water containing a large amount of permanent hardness components (e.g., sulfates such as calcium sulfate or chlorides such as magnesium chloride) as hardness components tends to have its pH lowered more easily during softening than water containing a large amount of temporary hardness components (e.g., carbonates such as calcium carbonate). Softening is difficult to achieve with a lowered pH, so the water flowing through the first softening tank 3 is passed into the first neutralization tank 4 for neutralization.

[0304] Water softened in the first softening tank 3 flows through the flow path 29 via the flow path switching valve 24 provided in the first softening tank 3 and flows into the first neutralization tank 4. In the first neutralization tank 4, the weakly basic anion exchange resin 34 adsorbs hydrogen ions contained in the softened water. Specifically, the removal of hydrogen ions from the water softened in the first softening tank 3 raises the lowered pH and neutralizes the water. Therefore, compared to directly softening the water softened in the first softening tank 3 in the second softening tank 5, the softening process in the second softening tank 5 is much easier.

[0305] The water neutralized in the first neutralization tank 4 (neutralized first soft water) flows through the flow path 30 via the flow path switching valve 25 provided in the first neutralization tank 4 and into the second soft water tank 5. In the second soft water tank 5, the weakly acidic cation exchange resin 33 adsorbs cations, which are hardness components, and releases hydrogen ions. The second soft water tank 5 exchanges the hardness components that could not be removed in the first soft water tank 3 for the hydrogen ions contained in the weakly acidic cation exchange resin 33. In other words, the water flowing into the second soft water tank 5 is further softened, becoming soft water (second soft water).

[0306] The second soft water flows through the flow path switching valve 26 installed in the second soft water tank 5, flows through the flow path 31, and then flows into the second neutralization tank 6. In the second neutralization tank 6, the weakly basic anion exchange resin 34 adsorbs the hydrogen ions contained in the incoming second soft water. This removal of hydrogen ions from the second soft water raises the pH, resulting in neutral soft water suitable for domestic use (neutralized second soft water). The neutralized second soft water flows through the flow path switching valve 27 installed in the second neutralization tank 6, flows through the flow path 32, and can be withdrawn from the water intake 7.

[0307] That is, during the water softening process, raw water flows sequentially through the first softening tank 3, the first neutralization tank 4, the second softening tank 5, and the second neutralization tank 6. Thus, raw water containing hardness components flows out of the first softening tank 3 before its pH further decreases due to the softening process in the first softening tank 3, is neutralized in the first neutralization tank 4, softened in the second softening tank 5, and neutralized in the second neutralization tank 6.

[0308] Therefore, compared to a case where the softening tank and the neutralization tank are separately configured, a decrease in the pH of the water flowing through the softening tank, i.e., an increase in acidity, can be suppressed. This facilitates the exchange of hardness components with hydrogen ions held by the weakly acidic cation exchange resin 33 in the softening tank (particularly the second softening tank 5). Consequently, the water softening performance can be improved.

[0309] Then, in the water softening device 1 , when the time period identified by the control unit 15 comes or when the amount of water subjected to the softening process exceeds a certain amount, the softening process is terminated and the regeneration process is executed.

[0310] (17.2 Regeneration process)

[0311] Next, refer to Figure 3 and Figure 8 In the column “During Regeneration”, the operation of the regeneration device 8 of the water softening device 1 during the regeneration process will be described in sequence.

[0312] In the water softening device 1, if the first and second softening tanks 3 and 5, filled with weakly acidic cation exchange resin 33, are used continuously, their cation exchange capacity decreases or even disappears. Specifically, the hydrogen ions, which are functional groups of the cation exchange resin, are completely exchanged with calcium or magnesium ions, which are hardness components, and ion exchange becomes impossible. Furthermore, even before all hydrogen ions are exchanged with hardness components, the ion exchange reaction becomes less likely as the number of hydrogen ions decreases, thus reducing the softening performance. If this condition persists, hardness components are incorporated into the treated water.

[0313] Therefore, in the water softening device 1 , it is necessary to perform regeneration processing of the first soft water tank 3 , the second soft water tank 5 , the first neutralization tank 4 , and the second neutralization tank 6 using the regeneration device 8 .

[0314] During the regeneration process, on-off valves 19, 20, and 22 are closed, and on-off valves 17, 18, 21, and 23 are opened. Furthermore, flow path switching valve 24 is connected so that water can be fed from the neutralization tank bypass flow path 42 to the first recovery flow path 37. Flow path switching valve 25 is connected so that water can be fed from the soft water tank bypass flow path 44 to the second recovery flow path 38. Flow path switching valve 26 is connected so that water can be fed from the first supply flow path 35 to the neutralization tank bypass flow path 42. Flow path switching valve 27 is connected so that water can be fed from the second supply flow path 36 to the soft water tank bypass flow path 44.

[0315] That is, the first soft water tank 3 and the second soft water tank 5 are in communication with each other, the first neutralization tank 4 and the second neutralization tank 6 are in communication with each other, and drainage from the drain port 13 and the capture portion drain port 14 is stopped.

[0316] Therefore, if Figure 3 As shown, a soft water tank regeneration circulation flow path 39 and a neutralization tank regeneration circulation flow path 40 are formed respectively.

[0317] Then, when the first water supply pump 11 and the second water supply pump 12 are operated, the acidic electrolyzed water and the alkaline electrolyzed water in the electrolytic tank 9 circulate in the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40, respectively.

[0318] Furthermore, in the electrolytic cell 9, electricity is applied so that the anode has a higher potential than the cathode (positive electrolysis). Consequently, during electrolysis, hydrogen ions are generated at the anode, producing acidic electrolyzed water near the anode. Meanwhile, hydroxide ions are generated at the cathode, producing alkaline electrolyzed water near the cathode.

[0319] The acidic electrolyzed water generated in the electrolytic cell 9 flows through the first supply flow path 35, is delivered to the second soft water tank 5 via the flow path switching valve 26, and flows through the weakly acidic cation exchange resin 33 therein. The acidic electrolyzed water that has flowed through the second soft water tank 5 then flows through the neutralization tank bypass flow path 42, is delivered to the first soft water tank 3 via the flow path switching valve 24, and flows through the weakly acidic cation exchange resin 33 therein.

[0320] Specifically, by passing acidic electrolyzed water through the weakly acidic cation exchange resin 33, cations (hardness components) adsorbed on the weakly acidic cation exchange resin 33 undergo an ion exchange reaction with hydrogen ions contained in the acidic electrolyzed water. This regenerates the weakly acidic cation exchange resin 33.

[0321] The acidic electrolyzed water flowing through the first soft water tank 3 contains cations and flows into the first recovery flow path 37 . That is, the acidic electrolyzed water containing cations flowing through the weakly acidic cation exchange resin 33 is recovered to the electrolytic cell 9 via the first recovery flow path 37 .

[0322] In this way, the soft water tank regeneration circulation flow path 39 is constructed as follows: the acidic electrolyzed water flows from the soft water tank located at the farthest downstream of the raw water inlet, that is, the soft water tank having a weakly acidic cation exchange resin 33 that adsorbs less hardness components than the soft water tank on the upstream side, that is, the downstream side of the second soft water tank 5, and flows into the downstream side of the first soft water tank 3 located upstream and having a weakly acidic cation exchange resin 33 that adsorbs more hardness components than the second soft water tank 5.

[0323] That is, the soft water tank regeneration circulation flow path 39 is a flow path that allows the acidic electrolyzed water sent from the electrolytic tank 9 to flow through the second soft water tank 5, and then to be sent to the first soft water tank 3 through the neutralization tank bypass flow path 42, so that it flows through the first soft water tank 3 and flows into the electrolytic tank 9 through the first recovery flow path 37.

[0324] Thus, during the regeneration process, the acidic electrolyzed water discharged from the electrolytic tank 9 flows into the second soft water tank 5 having a smaller adsorption amount of hardness components than the first soft water tank 3 , and the acidic electrolyzed water containing hardness components is discharged from the second soft water tank 5 to the first soft water tank 3 .

[0325] During the regeneration of the weakly acidic cation exchange resin 33 in the second soft water tank 5, the consumption of hydrogen ions in the acidic electrolyzed water is less than that in the first soft water tank 3. Therefore, the decrease in hydrogen ion concentration can be suppressed compared to the regeneration of the first soft water tank 3. Therefore, the acidic electrolyzed water containing a large amount of hydrogen ions flows into the first soft water tank 3, which can suppress the re-adsorption of hardness components in the first soft water tank 3. Consequently, a decrease in regeneration efficiency can be suppressed, and the regeneration time can be shortened.

[0326] On the other hand, the alkaline electrolyzed water generated near the cathode of the electrolytic cell 9 flows through the second supply flow path 36 and the capture unit 10, is delivered to the second neutralization tank 6 via the flow path switching valve 27, and flows through the weakly basic anion exchange resin 34 therein. Then, the alkaline electrolyzed water that has flowed through the second neutralization tank 6 flows through the soft water tank bypass flow path 44, is delivered to the first neutralization tank 4 via the flow path switching valve 25, and flows through the weakly basic anion exchange resin 34 therein.

[0327] Specifically, by passing alkaline electrolyzed water through the weakly basic anion exchange resin 34, anions adsorbed on the weakly basic anion exchange resin 34 undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water, thereby regenerating the weakly basic anion exchange resin 34.

[0328] The alkaline electrolyzed water containing anions flowing through the first neutralization tank 4 then flows into the second recovery channel 38 . That is, the alkaline electrolyzed water containing anions flowing through the weakly basic anion exchange resin 34 is recovered to the electrolytic tank 9 via the second recovery channel 38 .

[0329] In this way, the neutralization tank regeneration circulation flow path 40 is constructed so that alkaline electrolyzed water flows from the neutralization tank located at the farthest downstream of the raw water inlet, that is, the downstream side of the second neutralization tank 6 having a weakly basic anion exchange resin 34 that adsorbs less anions than the neutralization tank on the upstream side, and flows into the downstream side of the first neutralization tank 4 located upstream and having a weakly basic anion exchange resin 34 that adsorbs more anions than the second neutralization tank 6.

[0330] That is, the neutralization tank regeneration circulation flow path 40 is a flow path that allows the alkaline electrolyzed water sent from the electrolytic tank 9 to flow through the second neutralization tank 6, and then to be sent to the first neutralization tank 4 through the soft water tank bypass flow path 44, so that it flows through the first neutralization tank 4 and flows into the electrolytic tank 9 through the second recovery flow path 38.

[0331] Thus, during the regeneration step, alkaline electrolyzed water flows into the second neutralization tank 6 , which has a smaller anion adsorption amount than the first neutralization tank 4 , and the alkaline electrolyzed water containing anions is discharged from the second neutralization tank 6 to the first neutralization tank 4 .

[0332] In the regeneration of the weakly basic anion exchange resin 34 in the second neutralization tank 6 , the consumption of hydroxide ions in the alkaline electrolyzed water is less than that in the first neutralization tank 4 , so the decrease in hydroxide ion concentration can be suppressed compared to the regeneration of the first neutralization tank 4 .

[0333] Therefore, since alkaline electrolyzed water containing a large amount of hydroxide ions flows into the first neutralization tank 4, it is possible to suppress the re-adsorption of anions in the first neutralization tank 4. Therefore, it is possible to suppress a decrease in the regeneration treatment efficiency and shorten the regeneration time.

[0334] Furthermore, the neutralization tank regeneration circulation flow path 40 directs the alkaline electrolyzed water sent from the electrolytic tank 9 into the first neutralization tank 4 and the second neutralization tank 6 from their respective downstream sides, and causes it to flow out from the upstream side of each neutralization tank, where the amount of anions adsorbed is greater than that on the downstream side. Thus, the alkaline electrolyzed water flows in from the downstream side, where the amount of anion components adsorbed is less, and the neutralization tank is regenerated.

[0335] During regeneration of the weakly basic anion exchange resin 34, the consumption of hydroxide ions in the alkaline electrolyzed water is lower than that on the upstream side, thus suppressing a decrease in the hydroxide ion concentration of the alkaline electrolyzed water. Consequently, the reabsorption of anions contained in the alkaline electrolyzed water from the downstream side on the upstream side can be suppressed. Consequently, a decrease in the regeneration efficiency of the neutralization tank can be suppressed, shortening the regeneration time.

[0336] In addition, the "downstream side (or upstream side)" in the softening tank and the neutralization tank means the downstream side (or upstream side) in the flow path during the softening treatment.

[0337] Then, in the water softening device 1, when the time period identified by the control unit 15 is reached, or when the regeneration process exceeds a certain time (e.g., 4 hours), the regeneration process is terminated and the regeneration flow path cleaning process is performed. The certain time here is a time preset as the total regeneration operation time.

[0338] It should be noted that if the user wants to obtain soft water during the regeneration process, by opening a faucet connected to the softening device 1, raw water flows from the inlet 2 through the flow path 53 and out of the water intake 7. Therefore, raw water can be used even without waiting for the regeneration process to end.

[0339] When the regeneration process begins, the control unit 15 calculates the reference operating time, the number of times the replacement process is to be performed, including the replacement process during the reference operating time, and the timing for performing each replacement process using the reference operating time calculation unit 57 and the number of times determination unit 59. When the regeneration operating time reaches the timing for performing the replacement process, the control unit 15 stops the regeneration process and performs the replacement process.

[0340] (17.3 Replacement Process)

[0341] Next, refer to Figure 4 and Figure 8 In the column “During the replacement process”, the operation of the water softening device 1 during the replacement process will be described in sequence.

[0342] The replacement process is a step in which the acidic electrolyzed water with a high chloride ion concentration in the first and second soft water tanks 3 and 5 is drained and replaced with raw water. By performing the replacement process at the aforementioned frequency and timing, the average chloride ion concentration of the acidic electrolyzed water can be reduced to the chloride ion concentration reference value, thereby suppressing degradation of the electrodes in the electrolytic cell 9.

[0343] During the replacement process, on-off valve 17 and on-off valves 21-23 are closed, and on-off valves 18-20 are opened. Furthermore, flow path switching valve 24 is connected so that water can be fed from flow path 28 to neutralization tank bypass flow path 42. Flow path switching valve 25 is connected so that water can be fed to soft water tank bypass flow path 44. Flow path switching valve 26 is connected so that water can be fed from neutralization tank bypass flow path 42 to first supply flow path 35. Flow path switching valve 27 is connected so that water can be fed to second supply flow path 36. In other words, first soft water tank 3 and second soft water tank 5 are in communication, and second soft water tank 5 and drain outlet 13 are in communication.

[0344] Therefore, if Figure 4 As shown, the replacement flow path 70 is formed. It should be noted that by closing the on-off valve 17, the flow path 28 is disconnected from the first recovery flow path 37. It should be noted that at this time, the operation of the electrode 41, the first water pump 11 and the second water pump 12 is stopped.

[0345] In the replacement process, specifically, by opening the on-off valve 19 and closing the on-off valve 17 , raw water does not flow from the outside into the first recovery flow path 37 but flows into the replacement flow path 70 .

[0346] In the replacement flow path 70, the pressure of the incoming raw water is used to flush the acidic electrolyzed water with a high chloride ion concentration in the flow path 28, the first soft water tank 3, the neutralization tank bypass flow path 42, the second soft water tank 5, and the first supply flow path 35, and flow into the drain flow path 54. The acidic electrolyzed water with a high chloride ion concentration that has flowed into the drain flow path 54 is discharged outside the device through the drain port 13. Therefore, during the regeneration process, the chloride ion concentration that affects the deterioration of the electrodes 41 of the electrolytic cell 9 can be reduced to the chloride ion concentration of the raw water.

[0347] Therefore, it is possible to suppress degradation of the electrodes 41a of the electrolytic cell 9 due to high chloride ion concentrations. Furthermore, as in the replacement flow path 70, raw water flows only through the first soft water tank 3, the second soft water tank 5, and the first supply flow path 35, which contain acidic electrolyzed water with a high chloride ion concentration. This allows replacement with raw water while suppressing flow into the neutralization tank and electrolytic cell 9. This prevents wasteful drainage and reduces the amount of water required for the replacement process.

[0348] Then, in the water softening device 1, when it becomes a time period identified by the control unit 15, when the replacement process exceeds a certain time (for example, 10 minutes), or when the water flow rate in the replacement process exceeds a certain value (for example, 1.5 times the capacity of the replacement flow path 70), the replacement process is terminated and switched to the regeneration process.

[0349] It should be noted that if the user wants to obtain soft water during the replacement process, by opening a faucet connected to the water softening device 1, raw water flows from the inlet 2 through the flow path 53 and out of the water intake 7. Therefore, the raw water can be used even without waiting for the completion of the replacement process.

[0350] (17.4 Regeneration Flow Path Cleaning Procedure)

[0351] Next, refer to Figure 5 and Figure 8 In the column “Regeneration Flow Path Cleaning”, the operation of the water softening device 1 during the regeneration flow path cleaning step will be described in sequence.

[0352] In the water softening device 1 , hardness components are released from the first and second soft water tanks 3 , 5 into the acidic electrolyzed water during the regeneration process, and the acidic electrolyzed water circulates in the flow path without being discharged from the soft water tank regeneration circulation flow path 39 .

[0353] Therefore, after the regeneration process is completed, the soft water tank regeneration circulation flow path 39 is filled with high-hardness water containing hardness components released from the first soft water tank 3 and the second soft water tank 5. The hardness of this high-hardness water is significantly higher than the hardness of the raw water (for example, 450 ppm), and sometimes rises to about 2000 ppm.

[0354] When the water softening process is started while the high-hardness water remains in the water softening device 1, the high-hardness water or a mixture of raw water and high-hardness water is discharged from the water intake 7. Therefore, if the user of the water softening device 1 executes the water softening process after the regeneration process is completed, not only will no soft water be obtained immediately after the softening process begins, but water with a hardness higher than that of the raw water may also be obtained.

[0355] Furthermore, high-hardness water flows through the weakly acidic cation exchange resin 33 in the first and second soft water tanks 3 and 5. Although the hardness components adsorbed during the regeneration process are replaced with hydrogen ions, water containing hardness components also flows again. Therefore, the hydrogen ions that have been added through the painstaking regeneration process exchange with the hardness components, causing the hardness components to be adsorbed again on the weakly acidic cation exchange resin 33.

[0356] Therefore, the hydrogen ions available for softening the raw water decrease, and the softening performance is degraded. To solve these problems, a regeneration flow path cleaning step is performed to drain the high-hardness water in the soft water tank regeneration circulation flow path 39.

[0357] During the regeneration flow path cleaning process, close the switch valves 21 to 23, open the switch valves 17 to 20, set the flow path switching valve 24 to a connection state in which water can be supplied from the flow path 28 to the neutralization tank bypass flow path 42, set the flow path switching valve 25 to a connection state in which water can be supplied to the soft water tank bypass flow path 44, set the flow path switching valve 26 to a connection state in which water can be supplied from the neutralization tank bypass flow path 42 to the first supply flow path 35, and set the flow path switching valve 27 to a connection state in which water can be supplied to the second supply flow path 36.

[0358] Specifically, the first soft water tank 3 and the second soft water tank 5 are in communication with each other, the second soft water tank 5 is in communication with the drain port 13, the electrolytic tank 9 is in communication with the drain port 13, and drainage from the capture unit drain port 14 is stopped.

[0359] Therefore, if Figure 5 As shown, the first drain flow path 46 and the second drain flow path 47 are formed. Note that, at this time, the operation of the electrode 41, the first water pump 11, and the second water pump 12 are stopped.

[0360] In the regeneration flow path cleaning step, specifically, the on-off valve 19 is opened, so that raw water flows from the outside into the first drain flow path 46 and the second drain flow path 47 .

[0361] In first drain flow path 46, the pressure of the incoming raw water is used to flush the high-hardness water in flow path 28, first recovery flow path 37, first water supply pump 11, electrolytic cell 9, and first supply flow path 35, and the water flows into drain flow path 54. The high-hardness water flowing into drain flow path 54 is discharged outside the device through drain port 13.

[0362] In the second drain flow path 47, the pressure of the incoming raw water is used to flush the high-hardness water in the flow path 28, the first soft water tank 3, the neutralization tank bypass flow path 42, the second soft water tank 5, and the first supply flow path 35, and flow into the drain flow path 54. The high-hardness water that has flowed into the drain flow path 54 is discharged outside the device through the drain port 13.

[0363] In this way, the regeneration flow path cleaning process prevents the high-hardness water in the first drain flow path 46 and the second drain flow path 47, which are the main areas of high-hardness water remaining after the regeneration process, from flowing into the neutralization tank and is replaced with raw water. Therefore, during the regeneration flow path cleaning process, the adsorption of hydrogen ions onto the weakly basic anion exchange resin 34 in the neutralization tank can be suppressed, thereby suppressing the consumption of the hydroxide ions already filled, and maintaining neutralization performance. Consequently, the degradation of water softening performance caused by high-hardness water can be suppressed.

[0364] Note that the control unit 15 supplies raw water to each flow path so that the flow rate of raw water flowing through the second drain flow path 47 is greater than the flow rate of raw water flowing through the first drain flow path 46 .

[0365] This allows the high-hardness water in the second drain flow path 47, which contains the softening tank used during the water softening process and is necessary for draining the high-hardness water within the flow path, to be preferentially replaced with raw water. This prevents degradation of the softening performance caused by high-hardness water at the start of the water softening process. Furthermore, the first drain flow path 46 is not used during the water softening process and has minimal impact on the softening process even if high-hardness water remains. By reducing the amount of water discharged from the first drain flow path 46, wasted drainage can be prevented, and the amount of water required for the regeneration flow path cleaning process can be reduced.

[0366] Furthermore, this allows high-hardness water to be discharged from the device through a flow path that does not include the neutralization tank. Specifically, this prevents the hardness components in the high-hardness water stored in the regeneration flow path of the soft water tank from being discharged to the site of adsorption of the weakly basic anion exchange resin 34 in the neutralization tank. This prevents a decrease in softening performance due to high-hardness water generated during the regeneration process, maintaining softening performance.

[0367] Then, in the water softening device 1, when it becomes a time period identified by the control unit 15, when the regeneration flow path cleaning process exceeds a certain time (for example, 1 minute), or when the water flow rate in the regeneration flow path cleaning process exceeds a certain value, the regeneration flow path cleaning process is terminated and the electrolytic cell cleaning process is performed.

[0368] It should be noted that when the user wants to obtain soft water during the regeneration flow path cleaning process, by opening the faucet connected to the softening device 1, etc., the raw water flows from the inlet 2 through the flow path 53 and out of the water intake 7. Therefore, the raw water can be used even without waiting for the completion of the regeneration flow path cleaning process.

[0369] (17.5 Electrolytic Cell Cleaning Process)

[0370] Next, refer to Figure 6 and Figure 8 In the column “When the electrolytic cell is cleaned”, the operation of the water softening device 1 during the electrolytic cell cleaning process will be described in sequence.

[0371] In the regeneration process, if the electrolytic cell 9 is operating, hardness components (calcium ions and magnesium ions) in water are deposited on the cathode in the form of solid (scale).

[0372] The precipitate deposited on the cathode is a non-conductor, which increases the operating voltage of the electrolytic cell 9 and the power consumption during the regeneration process. Therefore, it is necessary to perform an electrolytic cell cleaning process to remove the precipitate deposited on the cathode.

[0373] During the electrolytic cell cleaning process, on-off valves 17 to 22 are opened, and on-off valve 23 is closed. Furthermore, flow path switching valve 24 is connected so that water can be supplied from flow path 28 to flow path 29, flow path switching valve 25 is connected so that water can be supplied to soft water tank bypass flow path 44, flow path switching valve 26 is connected so that water can be supplied to first supply flow path 35, and flow path switching valve 27 is connected so that water can be supplied to second supply flow path 36.

[0374] That is, the first soft water tank 3 and the electrolytic tank 9 are in a state of communication and connection, the electrolytic tank 9 and the drain port 13 are in a state of communication and connection, and the electrolytic tank 9 and the capture unit drain port 14 are in a state of communication and connection.

[0375] Therefore, if Figure 6 As shown, a first drain flow path 46 and a third drain flow path 50 are formed.

[0376] In the electrolytic cell cleaning step, specifically, by opening the on-off valve 19 , raw water flows from the outside into the first drain flow path 46 and the third drain flow path 50 .

[0377] The raw water flowing into the first drainage flow path 46 flows through the flow path 28 , the first recovery flow path 37 , and the first water supply pump 11 , and flows into the electrolytic cell 9 .

[0378] On the other hand, the raw water flowing into the third drainage flow path 50 flows through the flow path 28 , the first soft water tank 3 , the second recovery flow path 38 , and the second water supply pump 12 , and flows into the electrolytic cell 9 .

[0379] During the electrolytic cell cleaning process, the controller 15 applies electricity so that the cathode has a higher potential than the anode (reverse electrolysis). Consequently, the raw water flowing into the electrolytic cell 9 is electrolyzed to produce alkaline electrolyzed water near the anode and acidic electrolyzed water near the cathode.

[0380] At this time, the acidic electrolyzed water generated at the cathode can dissolve the precipitates deposited at the cathode, thereby suppressing the degradation of electrolytic performance due to the precipitates adhering to the surface of the electrode 41 .

[0381] The alkaline electrolyzed water generated at the anode flows through the first supply flow path 35 , flows into the drain flow path 54 , and is discharged to the outside of the device through the drain port 13 .

[0382] Meanwhile, the acidic electrolyzed water generated at the cathode dissolves the precipitates deposited at the cathode, flows through the second supply flow path 36, and flows into the capture unit 10. The acidic electrolyzed water flowing into the capture unit 10 can dissolve the precipitates captured by the capture unit 10, thereby preliminarily cleaning the capture unit 10. Therefore, the time required for the subsequent capture unit cleaning step can be shortened.

[0383] The acidic electrolyzed water is discharged from the capturing unit drain port 14 provided at the lower portion of the capturing unit 10 to the outside of the device.

[0384] That is, in the electrolytic cell cleaning step, the removal of precipitates in the electrolytic cell 9 and the removal of precipitates in the capturing portion 10 can be performed simultaneously, and the time required from the completion of the regeneration step to the start of the water softening step can be shortened.

[0385] Then, in the water softening device 1 , when the time period identified by the control unit 15 is reached or when the electrolytic cell cleaning process exceeds a certain time (eg, 5 minutes), the electrolytic cell cleaning process is terminated and the capturing unit cleaning process is executed.

[0386] Note that in the third drainage flow path 50, the raw water, having passed through the first soft water tank 3, becomes acidic and then passes through the capture section 10. Consequently, the capture section 10 is acidic, and the precipitates captured by the capture section 10 are dissolved by the acidic water. This allows for a preliminary cleansing of the capture section 10, shortening the time required for the subsequent capture section cleaning step.

[0387] That is, the removal of the precipitates in the electrolytic cell 9 and the removal of the precipitates in the capturing portion 10 can be performed simultaneously, and the time required from the completion of the regeneration step to the start of the water softening step can be shortened.

[0388] It should be noted that when the user wants to obtain soft water during the electrolytic cell cleaning process, by opening a faucet connected to the water softening device 1, raw water flows from the inlet 2 through the flow path 53 and out of the water intake 7. Therefore, the raw water can be used even without waiting for the completion of the electrolytic cell cleaning process.

[0389] (17.6 Capture Unit Cleaning Process)

[0390] Next, refer to Figure 7 and Figure 8 In the column “Cleaning the Capture Unit”, the operation of the water softening device 1 during the cleaning step of the capture unit will be described in sequence.

[0391] During the regeneration process, high-hardness water containing hardness components released from the first and second soft water tanks 3 and 5 flows into the electrolytic tank 9. During electrolysis, the hardness components migrate toward the cathode side and react with hydroxide ions generated there, forming precipitates. A portion of the precipitated precipitate is contained in the alkaline electrolyzed water released from the electrolytic tank 9, flows through the second supply flow path 36, and is captured by the capture unit 10.

[0392] Therefore, the precipitates gradually accumulate in the capture unit 10 during the regeneration process, and thus the pressure loss caused by the capture unit 10 gradually increases, and the flow rate of the alkaline electrolyzed water flowing through the neutralization tank regeneration circulation flow path 40 gradually decreases.

[0393] If the precipitate is left standing, the time required to regenerate the weakly basic anion exchange resin 34 in the first neutralization tank 4 and the second neutralization tank 6 will be prolonged, and there is a possibility that the weakly basic anion exchange resin 34 will not be completely filled with hydroxide ions. Therefore, a capture part cleaning step is required to remove the precipitate captured by or precipitated in the capture part 10.

[0394] During the capture unit cleaning process, on-off valves 18, 19, 22, and 23 are opened, and on-off valves 17, 20, and 21 are closed. Furthermore, flow path switching valve 24 is connected so that water can be supplied from flow path 28 to flow path 29, flow path switching valve 25 is connected so that water can be supplied from flow path 29 to flow path 30, flow path switching valve 26 is connected so that water can be supplied from flow path 30 to flow path 31, and flow path switching valve 27 is connected so that water can be supplied from flow path 31 to second supply flow path 36.

[0395] That is, the first soft water tank 3 is connected to the first neutralization tank 4, the first neutralization tank 4 is connected to the second soft water tank 5, the second soft water tank 5 is connected to the second neutralization tank 6, and the second neutralization tank 6 is connected to the capture part drain outlet 14.

[0396] Therefore, if Figure 7 As shown, a fourth drain flow path 52 (capturing portion cleaning flow path 51 ) is formed.

[0397] Specifically, during the capture unit cleaning process, open valve 19 allows raw water to flow from the outside into flow path 28. The flowing raw water then flows through flow path 28, first soft water tank 3, flow path 29, first neutralization tank 4, flow path 30, second soft water tank 5, flow path 31, second neutralization tank 6, and second supply flow path 36, before flowing into capture unit 10.

[0398] Neutral soft water flows into the capture section 10 from the opposite direction of water flow during the regeneration process. In other words, the inflowing neutral soft water performs reverse cleaning of the capture section 10. During this process, since some of the precipitates captured or deposited in the capture section 10 during the electrolytic cell cleaning process are pre-dissolved, cleaning of the capture section 10 with neutral soft water is facilitated. The neutral soft water, containing the precipitates, is discharged from the capture section drain port 14 located at the bottom of the capture section 10.

[0399] This allows the capture section 10 to be backwashed, thereby removing any precipitates remaining in the capture section 10. This prevents clogging of the capture section 10, and reduces pressure loss caused by the capture section 10 during the subsequent regeneration process. Consequently, a decrease in the flow rate of the regeneration flow path, i.e., the neutralization tank regeneration circulation flow path 40, which includes the capture section 10, can be suppressed, ensuring a sufficient flow rate of alkaline electrolyzed water and maintaining regeneration performance.

[0400] Then, in the water softening device 1 , when the time period identified by the control unit 15 arrives or when the capturing unit cleaning process exceeds a certain time (eg, 5 minutes), the capturing unit cleaning process is terminated and the water softening process is performed.

[0401] It should be noted that the flow path from the inlet 2 to the second neutralization tank 6 is the same as the flow path during the water softening process. Specifically, by using the fourth drain flow path 52, the second neutralization tank 6, the final neutralization tank in the water softening process, is filled with softened water. Therefore, by using the fourth drain flow path 52 to perform the capture unit cleaning process followed by the water softening process, users of the water softening device 1 can obtain softened water with reduced hardness from the water intake 7 immediately after the softening process begins.

[0402] It should be noted that when the user wants to obtain soft water during the capture part cleaning process, by opening a faucet connected to the softening device 1, raw water flows from the inlet 2 through the flow path 53 and out of the water intake 7. Therefore, the raw water can be used even without waiting for the capture part cleaning process to be completed.

[0403] As described above, in the water softening device 1 , the water softening step, the regeneration step, the regeneration flow path cleaning step, the electrolytic cell cleaning step, and the capture unit cleaning step are repeatedly performed in this order.

[0404] By performing the capture unit cleaning step immediately before the softening step, the neutralization tank at the final stage of the softening step is filled with softened water. Therefore, when the user of the softening device 1 turns on the faucet, high-hardness water is prevented from being discharged from the water intake 7, and soft water with a stable hardness can be provided from the start of the softening step.

[0405] Furthermore, by performing the electrolytic cell cleaning step after the regeneration flow path cleaning step, the high-hardness water is already discharged from the device during the polarity reversal during the electrolytic cell cleaning step, thus suppressing the possibility of electrolysis of high-hardness water. This suppresses the electrolysis of high-hardness water and prevents the formation of large amounts of scale in the flow path that transports alkaline electrolyzed water during the polarity reversal.

[0406] As described above, according to the water softening device 1 of the first embodiment, the following effects can be obtained.

[0407] (1) The softening device 1 performs a softening process for softening raw water and a regeneration process for regenerating ion exchange resins degraded by the softening process. The softening device 1 includes a softening tank that softens raw water containing hardness components using a weakly acidic cation exchange resin 33 to produce soft water in the softening process; a neutralization tank that neutralizes the acidic soft water that has passed through the softening tank using a weakly basic anion exchange resin 34 in the softening process; and an electrolytic cell 9 that produces electrolyzed water used in the regeneration process. The softening device 1 also includes an adsorption amount identification unit 55 that identifies the amount of chloride ions adsorbed in the softening tank based on the chloride ion concentration of the raw water and the amount of raw water passed into the softening tank; and a control unit 15 that controls the execution of the regeneration process based on the amount of chloride ions adsorbed determined by the adsorption amount identification unit 55. The control unit 15 is configured to execute a replacement process when the operation time of the regeneration process reaches a reference operation time. The replacement process stops the operation of the electrolytic cell 9, drains the acidic electrolyzed water in the soft water tank, and introduces raw water into the soft water tank.

[0408] With this configuration, during the regeneration process, the chloride ion concentration that affects the degradation of the electrodes 41a of the electrolytic cell 9 can be reduced to the chloride ion concentration of the raw water. Therefore, during the regeneration process after the reference operating time, the water softening device 1 can suppress catalyst degradation and extend the life of the electrolytic cell 9.

[0409] (2) In the case where the water softening device 1 performs a plurality of replacement steps within the reference operating time, the control unit 15 includes a number determination unit 59 that determines the number of replacement steps to be performed during the regeneration process based on the chloride ion concentration reference value, the chloride ion concentration of the raw water, the chloride ion adsorption amount, the reference operating time, and the total regeneration operating time. Based on the number of replacement steps determined by the number determination unit 59, the control unit 15 performs the replacement steps a plurality of times so that the time from the replacement step to the next replacement step is equal, thereby causing the average chloride ion concentration in the acidic electrolyzed water to be less than the chloride ion concentration reference value.

[0410] According to this configuration, a regeneration process at a reference chloride ion concentration can be performed even during the total regeneration operation time. Therefore, a water softening device having an electrolytic cell can further suppress catalyst degradation and maintain electrolysis performance for a long period of time.

[0411] The present disclosure has been described above based on the first embodiment. Those skilled in the art will appreciate that this embodiment is merely an example, and that various modifications are possible for combinations of components or processes, and that such modifications are also within the scope of the present disclosure.

[0412] In the water softening device 1 of the first embodiment, after the regeneration step is completed, the regeneration flow path cleaning step, the electrolytic cell cleaning step, and the capture unit cleaning step are sequentially performed, but the present invention is not limited thereto.

[0413] For example, the regeneration flow path cleaning step can be performed after the electrolytic cell cleaning step, and the capture unit cleaning step can be performed before the water softening step. Even if the cleaning process within the device is performed in this order, the precipitates in the electrolytic cell 9 and the capture unit 10 can be removed, and the second neutralization tank 6 can be filled with soft water immediately before the water softening step.

[0414] In the water softening device 1 of the first embodiment, the replacement process is performed so that the time from the replacement process to the next replacement process is uniform, but the present disclosure is not limited to this.

[0415] For example, based on actual experimental data, when the regeneration efficiency of chloride ions is high, that is, when the amount of chloride ions desorbed per unit time is large, the replacement process can be carried out in a manner that makes the time from the replacement process to the next replacement process shorter than the time from other replacement processes in the replacement process so far to the next replacement process of the other replacement process.

[0416] (Second embodiment)

[0417] Conventionally, a method has been known in which hardness components (e.g., calcium ions or magnesium ions) in raw water are adsorbed onto the weakly acidic cation exchange resin, which has hydrogen ions at the ends of its functional groups, thereby desorbing the hydrogen ions. In other words, raw water is softened by exchanging the hardness components for hydrogen ions.

[0418] Because cation exchange resins have a limited ability to adsorb hardness components, they need to be replaced or regenerated. A known method for regenerating cation exchange resins without using salt is to use acidic electrolyzed water generated by electrolysis (see, for example, Patent Document 1).

[0419] Water softened with a weakly acidic cation exchange resin becomes acidic due to the release of hydrogen ions in place of hardness components through the exchange of these components. To neutralize this acidic soft water, a weakly basic anion exchange resin is sometimes used in combination with the weakly acidic cation exchange resin. A known method for regenerating weakly basic anion exchange resins is to use alkaline electrolyzed water generated by electrolysis (see, for example, Patent Document 2).

[0420] To neutralize water softened and acidified by weakly acidic cation exchange resins, weakly basic anion exchange resins used in combination with weakly acidic cation exchange resins have a narrower effective pH range for ion exchange reactions than strongly basic anion exchange resins in the hydroxide ion (OH) form. Consequently, neutralization of acidic soft water to around pH 7 presents difficulties, and the ion exchange reaction rate near neutrality is slow. However, when strongly basic anion exchange resins or weakly basic anion exchange resins with a wide effective pH range are used to neutralize acidic soft water, they readily react even with bicarbonate ions, which have a low exchange order in the ion exchange reaction, resulting in the release of large amounts of bicarbonate ions during regeneration of the anion exchange resin.

[0421] Therefore, when configuring a regeneration system that circulates alkaline electrolyzed water, there are problems such as reduced electrolysis efficiency due to released bicarbonate ions or an increase in precipitates formed by the reaction of bicarbonate ions with hardness components in the electrolyzed water.

[0422] The present disclosure aims to solve the above-mentioned conventional problems and provides a water softening device capable of suppressing the influence of bicarbonate ions released during the regeneration of an anion exchange resin.

[0423] The water softening device disclosed herein performs a softening process for softening raw water and a regeneration process for regenerating ion exchange resins degraded by the softening process. The device comprises: a softening tank for softening raw water using a weakly acidic cation exchange resin to produce soft water; and a neutralization tank for neutralizing the pH of the acidic soft water passing through the softening tank using an anion exchange resin. The neutralization tank contains at least two separate anion exchange resins, including a first weakly basic anion exchange resin and a second anion exchange resin having a larger acid dissociation constant than the first anion exchange resin.

[0424] According to the present disclosure, it is possible to provide a water softening device that can suppress the influence of bicarbonate ions released during the regeneration of an anion exchange resin.

[0425] The second embodiment of the present disclosure is described below with reference to the accompanying drawings. It should be noted that the following embodiment is an example of a specific embodiment of the present disclosure and does not limit the technical scope of the present disclosure. Furthermore, the figures described in the embodiments are schematic, and the size and thickness ratios of the components in each figure do not necessarily reflect the actual dimensional ratios.

[0426] Reference Figure 12 A water softening device 101 according to a second embodiment of the present disclosure will be described.

[0427] Figure 12 : is a conceptual diagram showing the structure of the water softening device 101 according to the second embodiment of the present disclosure. Figure 12 , each element of the water softening device 101 is conceptually shown.

[0428] <1. Overall Structure>

[0429] The water softening device 101 produces neutral soft water from externally supplied raw water containing hardness. Neutral water includes not only a pH (hydrogen ion concentration index) of 7 but also a pH of approximately 6 to 8. Raw water refers to water (the water being treated) introduced into the device through the inlet 102, such as tap water or well water.

[0430] Raw water contains hardness components (e.g., calcium ions and magnesium ions). Using the water softening device 101 to perform a water softening process yields neutral soft water with a lower hardness than raw water, enabling the use of soft water even in areas with high raw water hardness. It should be noted that softening in the water softening device 101 means that the amount of hardness components in the softened water is less than that in the raw water.

[0431] Specifically, if Figure 12 As shown, the water softening device 101 includes an inlet 102 , a softening tank 103 , a neutralization tank 104 , a water intake 105 , a regeneration device 106 , and a control unit 114 .

[0432] The water softening device 101 includes an acidic electrolyzed water outlet 111, a capture unit outlet 112, an alkaline electrolyzed water outlet 113, a plurality of on-off valves (on-off valves 115 to 119), a three-way valve 120, and flow path switching valves 121 and 122. Details of these will be described later.

[0433] <2. Inlet and water intake>

[0434] The inlet 102 is connected to a raw water supply source and is an opening for introducing raw water into the water softening device 101 .

[0435] The water intake 105 is an opening for supplying softened water flowing through the softening device 101 to the outside of the device. In the softening device 101, the softened water can be taken out from the water intake 105 by using the pressure of the raw water flowing in from the inlet 102.

[0436] In the softening process of the softening process in the softening device 101, raw water supplied from the outside flows through the inlet 102, the flow path 123, the soft water tank 103, the flow path 124, the first neutralization tank 104a, the flow path 125, the second neutralization tank 104b, the flow path 126, the flow path 127 and the water intake 105 in this order, and is discharged as neutral soft water.

[0437] <3. Soft water tank>

[0438] The soft water tank 103 softens raw water containing hardness components by the action of the weakly acidic cation exchange resin 128 .

[0439] Specifically, the soft water tank 103 exchanges cations (calcium ions or magnesium ions) as hardness components contained in the circulating water (raw water) with hydrogen ions, thereby reducing the hardness of the raw water and softening the raw water.

[0440] The soft water tank 103 softens the raw water flowing in from the inlet 102. The soft water tank 103 includes a flow path switching valve 121. Details of the flow path switching valve will be described later.

[0441] The soft water tank 103 is filled with a weakly acidic cation exchange resin 128 .

[0442] The weakly acidic cation exchange resin 128 is an ion exchange resin having hydrogen ions at the ends of functional groups. The weakly acidic cation exchange resin 128 adsorbs cations (calcium ions and magnesium ions) as hardness components contained in the incoming raw water and releases hydrogen ions.

[0443] The soft water treated with the weakly acidic cation exchange resin 128 contains a large amount of hydrogen ions exchanged with the hardness components. In other words, the soft water flowing out of the soft water tank 103 is soft water that has been acidified by containing a large amount of hydrogen ions (acidic soft water).

[0444] Since the functional groups of the weakly acidic cation exchange resin 128 are terminated with hydrogen ions, the weakly acidic cation exchange resin 128 can be regenerated using acidic electrolyzed water in the regeneration step described later. At this time, the cations that were introduced during the water softening step and serve as hardness components are released from the weakly acidic cation exchange resin 128.

[0445] There are no particular limitations on the weakly acidic cation exchange resin 128, and a general-purpose resin can be used. For example, a resin having a carboxyl group (-COOH) as an exchange group can be used. In addition, a hydrogen ion (H ＋ ) can also be metal ions, or ammonium ions (NH4 ＋ ) and other cations.

[0446] <4. Neutralization tank>

[0447] The neutralization tank 104 (the first neutralization tank 104 a and the second neutralization tank 104 b ) neutralizes the pH of the soft water (acidified soft water) containing hydrogen ions discharged from the soft water tank 103 by the action of the weakly basic anion exchange resin 129 , thereby forming neutral soft water.

[0448] Specifically, the neutralization tank 104 adsorbs hydrogen ions contained in the soft water from the soft water tank 103 together with anions, thereby increasing the pH of the soft water to make neutral soft water.

[0449] The water softening device 101 of the second embodiment includes a first neutralization tank 104 a and a second neutralization tank 104 b as the neutralization tank 104 . Unless otherwise specified, the two are collectively referred to as the neutralization tank 104 .

[0450] The first neutralization tank 104 a is provided on the downstream side of the soft water tank 103 , and neutralizes the acidic soft water flowing through the soft water tank 103 .

[0451] The second neutralization tank 104b is provided downstream of the first neutralization tank 104a and neutralizes the soft water flowing through the first neutralization tank 104a. The second neutralization tank 104b includes a flow path switching valve 122.

[0452] The first neutralization tank 104 a and the second neutralization tank 104 b are filled with weakly basic anion exchange resins 129 (first weakly basic anion exchange resin 129 a and second weakly basic anion exchange resin 129 b ), respectively.

[0453] Different types of weakly basic anion exchange resins are used for the first weakly basic anion exchange resin 129a and the second weakly basic anion exchange resin 129b. The weakly basic anion exchange resin 129 is selected such that the acid dissociation constant (pKa) of the second weakly basic anion exchange resin 129b is approximately 2 greater than that of the first weakly basic anion exchange resin 129a.

[0454] The filling amount of the second weakly basic anion exchange resin 129b is preferably as small as possible in order to suppress adsorption of bicarbonate ions to the second weakly basic anion exchange resin 129b described later, within the range where the pH of the soft water passed into the second neutralization tank 104b is neutral.

[0455] Alternatively, a strongly basic anion exchange resin may be filled in the second neutralization tank 104b instead of the second weakly basic anion exchange resin 129b. It should be noted that when a strongly basic anion exchange resin is used, the amount of ion exchange resin filled is preferably reduced compared to when the second weakly basic anion exchange resin 129b is used in order to prevent the pH of the extracted soft water from becoming alkaline due to excessive ion exchange reactions.

[0456] The weakly basic anion exchange resin 129 adsorbs hydrogen ions contained in the water passed through to generate neutral water. The weakly basic anion exchange resin 129 is regenerated using alkaline electrolyzed water in a regeneration step described later.

[0457] As the weakly basic anion exchange resin 129 , a general-purpose resin can be used, and examples thereof include a free base type resin that becomes a tertiary amine.

[0458] <5. Regeneration device>

[0459] The regeneration device 106 is a device that regenerates the weakly acidic cation exchange resin 128 filled in the soft water tank 103 and regenerates the weakly basic anion exchange resin 129 filled in the first neutralization tank 104 a and the second neutralization tank 104 b .

[0460] Regeneration device 106 includes an electrolytic cell 107, a capture unit 108, a first water pump 109, and a second water pump 110. Furthermore, in regeneration device 106, a first supply flow path 130, a second supply flow path 131, a first recovery flow path 132, and a second recovery flow path 133 are connected to the soft water tank 103, the second neutralization tank 104b, the flow path 123, and the flow path 124, respectively. Details of each flow path will be described later.

[0461] It should be noted that the first supply flow path 130 , the second supply flow path 131 , the first recovery flow path 132 , the second recovery flow path 133 , the flow path 123 , the flow path 124 , and the flow path 125 form the soft water tank circulation regeneration flow path 142 and the neutralization tank circulation regeneration flow path 143 described later.

[0462] <5.1 Electrolytic Cell>

[0463] The electrolytic cell 107 electrolyzes water introduced therein using a pair of electrodes 134 (an anode 134 a and a cathode 134 b ) provided therein, thereby generating acidic electrolyzed water and alkaline electrolyzed water.

[0464] More specifically, in the regeneration process, hydrogen ions are generated by electrolysis at the anode 134a, producing acidic electrolyzed water. Separately, in the regeneration process, hydroxide ions are generated by electrolysis at the cathode 134b, producing alkaline electrolyzed water.

[0465] Then, the electrolytic tank 107 supplies the generated acidic electrolyzed water to the soft water tank 103 via the first supply flow path 130. Furthermore, the electrolytic tank 107 supplies the generated alkaline electrolyzed water to the first neutralization tank 104a and the second neutralization tank 104b via the second supply flow path 131 and the flow path 125.

[0466] As will be described in detail later, the acidic electrolyzed water generated by the electrolytic cell 107 is used to regenerate the weakly acidic cation exchange resin 128 in the soft water tank 103, and the alkaline electrolyzed water generated by the electrolytic cell 107 is used to regenerate the weakly basic anion exchange resin 129 in the first neutralization tank 104a and the second neutralization tank 104b.

[0467] The electrolytic cell 107 is configured so that the state of electricity supplied to the anode 134 a and the cathode 134 b can be controlled by a control unit 114 described later.

[0468] Electrolytic cell 107 includes a diaphragm 150, a porous membrane that separates the liquids, within the cell. Diaphragm 150 prevents mixing of the acidic electrolyzed water and the alkaline electrolyzed water by convection while enabling ion migration by electrophoresis. This prevents the hydrogen ions in the acidic electrolyzed water and the hydroxide ions in the alkaline electrolyzed water from being consumed by neutralization reactions, thereby suppressing a decrease in the regeneration efficiency of weakly acidic cation exchange resin 128 and weakly basic anion exchange resin 129.

[0469] <5.2 Water supply pump>

[0470] The first water pump 109 is a device for circulating the acidic electrolyzed water in the soft water tank 103 during the regeneration process performed by the regeneration device 106 .

[0471] The first water supply pump 109 is provided in the first recovery flow path 132 which connects the soft water tank 103 and the electrolytic tank 107. This arrangement is adopted in order to facilitate the circulation of the acidic electrolyzed water using only the first water supply pump 109.

[0472] The second water pump 110 is a device for circulating alkaline electrolyzed water through the first neutralization tank 104 a and the second neutralization tank 104 b during the regeneration process by the regeneration device 106 .

[0473] The second water supply pump 110 is provided in the second recovery flow path 133 which connects the first neutralization tank 104a and the electrolytic tank 107. This arrangement is adopted to facilitate the circulation of alkaline electrolyzed water using only the second water supply pump 110.

[0474] Furthermore, the first water pump 109 and the second water pump 110 are connected to a control unit 114 to be described later in a wireless or wired manner so as to be communicable.

[0475] <5.3 Capture part>

[0476] The capture unit 108 is provided in the second supply flow path 131 connecting the electrolytic cell 107 and the second neutralization tank 104b. In other words, the capture unit 108 is provided downstream of the electrolytic cell 107 and upstream of the neutralization tank 104 during the regeneration process.

[0477] The capture unit 108 captures precipitates contained in the alkaline electrolyzed water sent from the electrolytic cell 107. The precipitates are reaction products generated by the reaction of hardness components as cations released from the soft water tank 103 during the regeneration process in the electrolytic cell 107 with the alkaline electrolyzed water.

[0478] More specifically, while water is electrolyzed in electrolytic cell 107, hardness components (e.g., calcium ions or magnesium ions) released from soft water tank 103 during the regeneration process migrate from the anode (anode 134a) to the cathode (cathode 134b) via the diaphragm. Since alkaline electrolyzed water is generated on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates.

[0479] For example, when the hardness component is calcium ions, mixing with alkaline electrolyzed water causes a reaction to produce calcium carbonate or a reaction to produce calcium hydroxide. Furthermore, precipitates derived from the hardness component accumulate on the cathode side of the electrolytic cell 107 or flow out from the cathode side of the electrolytic cell 107 to the second supply flow path 131.

[0480] In contrast, by providing a capture portion 108 on the flow path on the downstream side of the electrolytic tank 107 and the upstream side of the neutralization tank 104, i.e., the second supply flow path 131, the capture portion 108 can be used to capture precipitates originating from the hardness component, thereby preventing the precipitates from flowing into the neutralization tank 104 and accumulating in the neutralization tank 104.

[0481] When the capture unit 108 is not provided on the downstream side of the electrolytic tank 107 and the upstream side of the neutralization tank 104, when the softening process is restarted after the regeneration process is completed, the precipitates accumulated in the neutralization tank 104 react with the hydrogen ions in the acidic soft water released from the soft water tank 103 and are ionized.

[0482] As a result, the soft water discharged from the neutralization tank 104 contains hardness components again, and therefore has a higher hardness than when discharged from the previously installed soft water tank 103. In contrast, by providing the capture unit 108 in the second supply flow path 131, it is possible to suppress the accumulation of precipitates in the neutralization tank 104 and the increase in hardness associated with dissolution.

[0483] It should be noted that “the hardness components react” includes not only the case where all the hardness components react, but also the state where components that do not react or components that do not exceed the solubility product are included after the reaction.

[0484] The capture unit 108 may be of any form as long as it can separate the precipitate produced by the reaction of the hardness component with the alkaline electrolyzed water. For example, a cylindrical filter, a filter layer using a granular filter material, a cyclone-type solid-liquid separator, or a hollow fiber membrane may be used.

[0485] A cartridge filter is a commonly used mechanism for capturing the portion 108. The cartridge filter may be a depth filter such as a wire wound filter, a surface filter such as a pleated filter or a membrane filter, or a combination thereof.

[0486] The capturing unit 108 is connected to a capturing unit drain flow path 137 , and the capturing unit drain flow path 137 includes an on-off valve 119 and a capturing unit drain port 112 .

[0487] The on-off valve 119 is a valve provided at the bottom of the capture unit 108, and is used to control the drainage of the capture unit 108. By opening the on-off valve 119, the water in the capture unit 108 can be discharged from the capture unit drain port 112 to the outside of the device through the capture unit drainage flow path 137. In addition, after the regeneration process described later is completed, the neutralization tank circulation regeneration flow path 143 ( Figure 15 The water in the container (as shown) is drained out of the device.

[0488] The capture unit drain port 112 is an opening for draining water from the capture unit 108 to the outside of the device. By opening the on-off valve 119 provided upstream of the capture unit drain port 112, the water from the capture unit 108 can be drained from the capture unit drain port 112 to the outside of the device.

[0489] <6. On-off valves, three-way valves, and flow path switching valves>

[0490] A plurality of on-off valves (on-off valves 115 to 119 ) are provided in each flow path, respectively, and switch between an “open” state and a “closed” state in each flow path.

[0491] The flow of water to each flow path is started or stopped by opening and closing a plurality of on-off valves (on-off valve 115 , on-off valve 116 , and on-off valve 118 ).

[0492] The on-off valve 117 and the on-off valve 119 are opened during the drainage process when switching to the water softening process after the regeneration process is completed, which will be described later.

[0493] The three-way valve 120 is provided on the flow path 125 and is connected to the alkaline electrolyzed water drainage flow path 138. The flow direction of each flow path is switched by rotating the three-way valve 120.

[0494] The flow path switching valves 121 and 122 are provided in the soft water tank 103 and the second neutralization tank 104b, respectively.

[0495] Each flow path switching valve has three openings. The first opening is an inlet and outlet that allows water to flow in and out. The second opening is an inlet that does not function as an outlet for water to flow out but as an inlet for water to flow in. The third opening is an outlet that does not function as an inlet for water to flow in but as an outlet for water to flow out.

[0496] In the multiple flow path switching valves, both the inlet and outlet are always "open." Depending on the direction of water flow, when either the inlet or outlet is "open," the other is "closed." The provision of flow path switching valves 121 and 122 reduces the number of on-off valves required for each flow path within the water softening device 101, thereby reducing the cost of the water softening device 101.

[0497] The plurality of on-off valves (on-off valves 115 to 119 ), the three-way valve 120 , and the flow path switching valves 121 and 122 are each connected to a control unit 114 to be described later in a communicative manner wirelessly or by wire.

[0498] <7. Drainage outlet>

[0499] The acidic electrolyzed water drain outlet 111 is an opening provided at the end of the acidic electrolyzed water drain passage 136, and is used to connect the soft water tank regeneration passage 142 (see Figure 15 ) to an opening outside the device.

[0500] An on-off valve 117 is provided upstream of the acidic electrolyzed water drain port 111 . By opening the on-off valve 117 , water can be discharged from the acidic electrolyzed water drain port 111 .

[0501] The acidic electrolyzed water drain port 111 discharges the water in the soft water tank circulation regeneration flow path 142 to the outside of the device after the regeneration process described later is completed.

[0502] The capture unit drain port 112 is an opening provided at the bottom of the capture unit 108, and is used to connect the neutralization tank regeneration flow path 143 (see Figure 15 ) to an opening outside the device.

[0503] An on-off valve 119 is provided upstream of the capture unit drain port 112. Opening the on-off valve 119 allows water to be discharged from the capture unit drain port 112. The capture unit drain port 112 discharges water in the neutralization tank circulation regeneration flow path 143 to the outside of the device after the regeneration process described below is completed.

[0504] The alkaline electrolyzed water drain port 113 is an opening provided at the end of the alkaline electrolyzed water drain channel 138 , and is an opening for discharging the alkaline electrolyzed water flowing out of the second neutralization tank 104 b to the outside of the apparatus in the water injection and regeneration step described later.

[0505] A three-way valve 120 is provided upstream of the alkaline electrolyzed water outlet 113 . By rotating the three-way valve 120 , water can be discharged from the alkaline electrolyzed water outlet 113 .

[0506] The details will be described later. The alkaline electrolyzed water outlet 113 is a neutralization tank regeneration flow path 141 (see Figure 14 The alkaline electrolyzed water generated by the electrolytic cell 107 is passed into the second neutralization tank 104b and used to regenerate the second weakly basic anion exchange resin 129b, and then discharged from the alkaline electrolyzed water outlet 113 through the alkaline electrolyzed water drainage channel 138.

[0507] <8.Flow path>

[0508] Bypass flow path 135 connects inlet 102 to flow path 127 and is provided with an on-off valve 115. Bypass flow path 135 allows raw water to bypass softening tank 103 and neutralization tank 104, bypassing them and being delivered as untreated water to the downstream side of neutralization tank 104.

[0509] Furthermore, the bypass flow path 135 allows the user of the water softening device 101 to obtain raw water from the water intake 105 even when the regeneration process is being performed.

[0510] <8.1 Water Softening Path>

[0511] Reference Figure 13 The softening flow path 139 formed during the water softening step of the water softening device 101 will be described.

[0512] Figure 13 It is a diagram showing the water softening flow path 139 of the water softening device 101 .

[0513] Softening flow path 139 ( Figure 13 The oblique line arrows 139 are the flow paths for softening raw water. The raw water flowing through the softening flow path 139 becomes neutral soft water and is discharged from the water intake port 105 to the outside of the device.

[0514] The softening flow path 139 is a flow path that passes water through the inlet 102, flow path 123, the soft water tank 103, flow path 124, the first neutralization tank 104a, flow path 125, the second neutralization tank 104b, flow path 126 and flow path 127, which serve as a path for passing water in the soft water tank 103 and the neutralization tank 104, and transports soft water to the water intake 105.

[0515] The flow path 123 is a flow path connected to the soft water tank 103 from the inlet 102. That is, the flow path 123 is a flow path that guides the raw water containing hardness components from the inlet 102 to the soft water tank 103.

[0516] The flow path 124 is a flow path connected to the first neutralization tank 104a from the soft water tank 103. In other words, the flow path 124 is a flow path that guides the water softened in the soft water tank 103 to the first neutralization tank 104a.

[0517] The flow path 125 is a flow path connecting the first neutralization tank 104a to the second neutralization tank 104b. In other words, the flow path 125 is a flow path that guides the water neutralized in the first neutralization tank 104a to the second neutralization tank 104b.

[0518] The flow path 126 is a flow path connected from the second neutralization tank 104b to the flow path 127. That is, the flow path 126 is a flow path that guides softened raw water from the second neutralization tank 104b to the flow path 127.

[0519] Flow path 127 connects flow path 126 to water inlet 105 and bypass flow path 135 to water inlet 105. In other words, flow path 127 guides softened raw water from flow path 126 to water inlet 105 and guides raw water from bypass flow path 135 to water inlet 105.

[0520] like Figure 13 As shown, an on-off valve 116 is provided in the flow path 123 on the downstream side of the inlet 102 and the upstream side of the soft water tank 103 .

[0521] By closing the on-off valve 115 and opening the on-off valve 116, the soft water tank 103 is connected to the inlet 102. Then, the flow path switching valve 121 is switched to connect the soft water tank 103 to the first neutralization tank 104a, and the flow path switching valve 122 is switched to connect the second neutralization tank 104b to the water intake 105.

[0522] Thus, a softening water flow path 139 is formed which communicates from the inlet 102 to the flow path 123 , the softening tank 103 , the flow path 124 , the first neutralization tank 104 a , the flow path 125 , the second neutralization tank 104 b , the flow path 126 , the flow path 127 and the water intake 105 .

[0523] <8.2 Water injection path>

[0524] Reference Figure 14 The water injection flow path 140 formed during the water injection and regeneration process of the water softening device 101 will be described.

[0525] Figure 14 1 is a diagram showing a water injection flow path 140 and a neutralization tank regeneration flow path 141 of the water softening device 101 .

[0526] Water injection channel 140 ( Figure 14 The gray arrow in FIG14 is a flow path for supplying raw water to the electrolytic cell 107. The raw water supplied to the electrolytic cell 107 is electrolyzed in the electrolytic cell 107 by the water injection flow path 140 to generate acidic electrolyzed water and alkaline electrolyzed water.

[0527] The water injection flow path 140 includes an anode chamber supply flow path for supplying raw water to the anode chamber where the anode 134a is located in the electrolytic cell 107, and a cathode chamber supply flow path for supplying raw water to the cathode chamber where the cathode 134b is located.

[0528] The anode chamber supply flow path is a flow path that allows water to flow through the inlet 102 , the flow path 123 , the first recovery flow path 132 , and the electrolytic cell 107 , and supplies water from the inlet 102 to the electrolytic cell 107 .

[0529] The cathode chamber supply flow path is a path for supplying raw water to the cathode chamber where the cathode 134 b is located, and is a flow path that feeds from the inlet 102 to the flow path 123 , the soft water tank 103 , the flow path 124 , the second recovery flow path 133 and the electrolytic cell 107 .

[0530] By closing the on-off valve 115 and opening the on-off valve 116, the soft water tank 103 is connected to the inlet 102. Then, the flow path switching valve 121 is switched so that the soft water tank 103 is connected to the first neutralization tank 104a, the flow path switching valve 122 is switched so that the first neutralization tank 104a is connected to the second neutralization tank 104b, and the three-way valve 120 is switched so that the second neutralization tank 104b is connected to the alkaline electrolyzed water discharge flow path 138.

[0531] This forms the water injection flow path 140 and the neutralization tank regeneration flow path 141 described later. Note that by opening the on-off valve 115 , the user of the water softening device 101 can also obtain raw water from the water intake 105 during the water injection and regeneration process.

[0532] <8.3 Neutralization tank regeneration flow path>

[0533] Reference Figure 14 The neutralization tank regeneration flow path 141 formed during the water filling and regeneration process of the water softening device 101 will be described. Figure 14The neutralization tank regeneration flow path 141 of the water softening device 101 is also shown.

[0534] Neutralization tank regeneration flow path 141 ( Figure 14 The black arrow in FIG10 is a flow path for supplying and discharging the alkaline electrolyzed water generated by electrolysis in the electrolytic tank 107 to the second neutralization tank 104b.

[0535] In the neutralization tank regeneration flow path 141 , the alkaline electrolyzed water supplied to the second neutralization tank 104 b is used to regenerate the second weakly basic anion exchange resin 129 b in the second neutralization tank 104 b and is then discharged.

[0536] The neutralization tank regeneration flow path 141 is a path for supplying alkaline electrolyzed water from the cathode chamber of the electrolytic tank 107 to the second neutralization tank 104 b and the alkaline electrolyzed water discharge port 113 .

[0537] Specifically, the neutralization tank regeneration flow path 141 is a flow path that allows water to flow through the electrolytic tank 107, the second supply flow path 131, the capture unit 108, the second neutralization tank 104b, the flow path 125, the alkaline electrolyzed water drainage flow path 138 and the alkaline electrolyzed water drainage port 113, and transports water from the electrolytic tank 107 to the alkaline electrolyzed water drainage port 113.

[0538] By opening the on-off valve 118 , the three-way valve 120 is switched so that the second neutralization tank 104 b is in communication with the alkaline electrolyzed water drainage flow path 138 , thereby forming the neutralization tank regeneration flow path 141 .

[0539] <8.4 Regeneration Flow Path>

[0540] Next, refer to Figure 15 , the softening tank circulation regeneration flow path 142 and the neutralization tank circulation regeneration flow path 143 formed in the circulation regeneration mode of the water softening device 101 will be described.

[0541] Figure 15 14 is a diagram showing a softening tank circulation and regeneration flow path 142 and a neutralization tank circulation and regeneration flow path 143 of the water softening device 101 .

[0542] It should be noted that, in this embodiment, the soft water tank circulation and regeneration flow path 142 and the neutralization tank circulation and regeneration flow path 143 are collectively referred to as a circulation and regeneration flow path.

[0543] First, the soft water tank circulation and regeneration flow path 142 will be described.

[0544] The soft water tank regeneration flow path 142 is a flow path for regenerating the soft water tank 103 by circulating acidic electrolyzed water in the regeneration mode. Figure 15As shown by (white arrow), the water delivered by the first water delivery pump 109 flows through the electrolytic cell 107 and the soft water tank 103 and returns to the electrolytic cell 107 to circulate.

[0545] Specifically, the soft water tank circulation and regeneration flow path 142 is composed of a first supply flow path 130 and a first recovery flow path 132 . The electrolytic cell 107 , the soft water tank 103 , and the first water supply pump 109 are provided in the soft water tank circulation and regeneration flow path 142 .

[0546] The first supply flow path 130 is a flow path that connects from the downstream side of the electrolytic cell 107 in the circulation regeneration mode to the downstream side of the softening tank 103 in the water softening process, and is a flow path for supplying acidic electrolyzed water from the electrolytic cell 107 to the softening tank 103 .

[0547] The first recovery flow path 132 is a flow path that connects the upstream side of the softening tank 103 to the electrolytic tank 107 during the water softening process. It is a flow path that recovers the acidic electrolyzed water containing hardness components that has passed through the softening tank 103 to the electrolytic tank 107. A first water supply pump 109 is provided in the first recovery flow path 132.

[0548] The soft water tank regeneration flow path 142 guides the acidic electrolyzed water sent from the electrolytic tank 107 to the soft water tank 103 from the downstream side during the water softening process, and flows out from the upstream side of the soft water tank 103 where the amount of hardness components adsorbed is greater than that of the downstream side.

[0549] Next, the neutralization tank circulation regeneration flow path 143 will be described.

[0550] The neutralization tank regeneration flow path 143 is a flow path for regenerating the first neutralization tank 104a and the second neutralization tank 104b by circulating alkaline electrolyzed water in the regeneration mode. Figure 15 Indicated by (black arrows) is a flow path in which water delivered by the second water delivery pump 110 circulates through the electrolytic tank 107 , the second neutralization tank 104 b , and the first neutralization tank 104 a and returns to the electrolytic tank 107 .

[0551] Specifically, the neutralization tank circulation regeneration flow path 143 is composed of the second supply flow path 131, the flow path 125 and the second recovery flow path 133, and the electrolytic cell 107, the second neutralization tank 104b, the first neutralization tank 104a and the second water supply pump 110 are arranged on the neutralization tank circulation regeneration flow path 143.

[0552] The second supply flow path 131 is a flow path that connects the downstream side of the electrolytic cell 107 during the regeneration process to the downstream side of the second neutralization tank 104b during the water softening process. This flow path supplies alkaline electrolyzed water from the electrolytic cell 107 to the second neutralization tank 104b. The second supply flow path 131 is provided with an on-off valve 118 and a capture unit 108.

[0553] The flow path 125 is a flow path for supplying alkaline electrolyzed water from the second neutralization tank 104b to the first neutralization tank 104a during the regeneration step.

[0554] The second recovery flow path 133 is a flow path that connects to the electrolytic cell 107 from the upstream side of the first neutralization tank 104a during the water softening process, and is a flow path that recovers the alkaline electrolyzed water that has passed through the first neutralization tank 104a and the second neutralization tank 104b to the electrolytic cell 107. The second water supply pump 110 is provided in the second recovery flow path 133.

[0555] <9. Control Department>

[0556] Each function executed by the control unit 114 of this embodiment will be described.

[0557] The control unit 114 controls the execution of the water softening process, the execution of the water injection and regeneration process, the execution of the water discharge process, and the switching between processes (see Figure 16 Regarding the timing of switching, for example, switching can be performed when the time point is a predetermined reference time. It should be noted that the predetermined reference time refers to a continuous time period during which the softening process is performed less frequently.

[0558] As a method of identifying the predetermined time period, namely, the reference time, for example, the predetermined reference time may be set in advance, or the predetermined reference time may be determined based on actual usage conditions to determine a time period when the possibility of performing the water softening process is low.

[0559] For example, a time period during which the water softening process is not performed is pre-set and designated as a predetermined reference time for the water filling and regeneration process. Specifically, if the time period during which the water softening process is not performed is set to 11 PM to 6 AM, the control unit 114 determines that the water filling and regeneration process will be performed within this time period (7 hours).

[0560] As another determination method, for example, the control unit 114 monitors the usage of the water softening device 101 and records the time periods during which the water softening process is performed. Based on this time period information, the control unit 114 can identify time periods when the water softening process is less frequent and determine to perform the water filling and regeneration process during these time periods. Specifically, the control unit 114 can monitor usage over the past month and calculate the average time period during which the amount of soft water used is lower compared to the time period during which the water softening process is performed, and use this as the predetermined reference time period.

[0561] Furthermore, the control unit 114 controls the on-off valve 117 and the on-off valve 119 to control drainage during the drainage process.

[0562] Furthermore, the control unit 114 controls the flow path switching valves 121 and 122 , the on-off valve 115 , the on-off valve 116 , the on-off valve 118 , and the three-way valve 120 to switch the flow paths.

[0563] The various components of control unit 114 can be implemented as hardware using components and mechanical devices, such as a computer's CPU (Central Processing Unit), or as software using computer programs, etc. Here, it is assumed that these components are implemented through the collaboration of these components. Therefore, these various functions can be implemented in various forms through a combination of hardware and software.

[0564] The above is the structure of the water softening device 101.

[0565] Next, the operation of the water softening device 101 will be described.

[0566] <10. Water Softening, Water Filling and Regeneration, and Drainage>

[0567] Reference Figure 16 The water softening process, water injection and regeneration process, and water discharge process of the water softening device 101 will be described.

[0568] Figure 16 It is a diagram showing the operating state of each component when the water softening device 101 is in operation.

[0569] like Figure 16 As shown, in the water softening process, the water injection and regeneration process, and the drainage process, the control unit 114 switches the switch valves 115 to 119, the three-way valve 120, the flow path switching valves 121, 122, the anode 134a and the cathode 134b of the electrolytic cell 107, and the first water supply pump 109 and the second water supply pump 110, and controls them in such a way that they become their respective flow states.

[0570] Here, Figure 16 The "ON" column indicates that the corresponding switch valve is "open", the electrode 134 is energized, and the corresponding water pump is operating. On the other hand, blank columns indicate that the corresponding switch valve is "closed", the electrode 134 is not energized, and the corresponding water pump is stopped.

[0571] in addition, Figure 16 The phrase "from (component A's number) to (component B's number)" indicates that the corresponding three-way valve and flow path switching valve are connected in a manner that allows water to flow from component A to component B. For example, flow path switching valve 121 in the water softening process connects the flow paths so that water can flow from flow path 123 to flow path 124.

[0572] <10.1 Water Softening Process>

[0573] First, refer to Figure 13 and Figure 16 The column “during water softening” explains the operation when the water softening process is performed by the water softening device 101.

[0574] In the water softening device 101, as Figure 16 As shown, in the water softening process, the on-off valve 116 provided in the flow path 123 is opened while the on-off valve 115 is closed. This allows raw water containing hardness components to flow in from the outside.

[0575] Since the inflowing raw water flows through the soft water tank 103 , the first neutralization tank 104 a , and the second neutralization tank 104 b in this order, softened water (neutral soft water) can be taken out from the water intake 105 in the water softening device 101 .

[0576] At this point, flow path switching valve 121 is connected to enable water flow from flow path 123 to flow path 124, and flow path switching valve 122 is connected to enable water flow from flow path 125 to flow path 126. On-off valves 117-119 are all closed. Three-way valve 120 is connected to enable water flow from flow path 125 to flow path switching valve 122. Furthermore, the electrodes 134 of electrolytic cell 107, first water pump 109, and second water pump 110 are also stopped.

[0577] Specifically, if Figure 13 As shown, in the water softening process, raw water is supplied from the inlet 102 through the flow path 123 to the soft water tank 103 by the pressure of the raw water flowing in from the outside. Then, the raw water supplied to the soft water tank 103 flows through the weakly acidic cation exchange resin 128 provided in the soft water tank 103.

[0578] At this point, the cations in the raw water, which are hardness components, are adsorbed by the weakly acidic cation exchange resin 128, releasing hydrogen ions (ion exchange). The cations are then removed from the raw water, softening it. Since the softened water contains a large amount of hydrogen ions released in exchange for hardness components, it becomes acidic, resulting in a low pH (hydrogen ion concentration index) (acidic soft water).

[0579] Here, when water containing a large amount of permanent hardness components (for example, sulfates such as calcium sulfate or chlorides such as magnesium chloride) as hardness components is softened, its pH is more likely to decrease than when water containing a large amount of temporary hardness components (for example, carbonates such as calcium carbonate) is softened.

[0580] Acidic soft water flows through flow path 124 via flow path switching valve 121 installed in soft water tank 103 and into first neutralization tank 104a. In first neutralization tank 104a, hydrogen ions contained in the softened water are adsorbed by first weakly basic anion exchange resin 129a. Specifically, the removal of hydrogen ions from the softened water in soft water tank 103 raises the lowered pH, leading to neutralization.

[0581] The water neutralized in the first neutralization tank 104a (neutralized first soft water) flows through the flow path 125 and into the second neutralization tank 104b. In the second neutralization tank 104b, the hydrogen ions contained in the incoming neutralized first soft water are adsorbed by the second weakly basic anion exchange resin 129b. This further removes hydrogen ions from the neutralized first soft water, raising its pH and resulting in neutral soft water suitable for domestic use (neutralized second soft water).

[0582] The neutralized second soft water flows through the flow path 126 and the flow path 127 via the flow path switching valve 122 provided in the second neutralization tank 104 b and can be taken out from the water intake port 105 .

[0583] Specifically, in the softening process, raw water flows sequentially through the softening tank 103, the first neutralization tank 104a, and the second neutralization tank 104b. Thus, raw water containing hardness components is softened by the softening process in the softening tank 103 and neutralized in the first and second neutralization tanks 104a, 104b.

[0584] In the above configuration, if the second neutralization tank 104b filled with the second weakly basic anion exchange resin 129b having a larger acid dissociation constant (pKa) than the first weakly basic anion exchange resin 129a is not provided, and if water is passed only through the first neutralization tank 104a, the removal of hydrogen ions in the acidic soft water may be insufficient, and the soft water taken out may not be completely neutralized, resulting in a weakly acidic pH of approximately 5 to 5.9.

[0585] This is because the first weakly basic anion exchange resin 129 a has a low acid dissociation constant, so once the acidic soft water is neutralized to a certain extent (pH 5 to 5.9), the ion exchange reaction rate decreases, that is, the neutralization reaction rate decreases or no neutralization reaction occurs.

[0586] Therefore, in order to neutralize the extracted soft water by simply passing water through the first neutralization tank 104a, it is necessary to increase the filling amount of the first weakly basic anion exchange resin 129a in the first neutralization tank 104a or reduce the flow rate of raw water to the softening device 101 in the softening process.

[0587] In addition, when only the second weakly basic anion exchange resin 129b is used, under the condition that the acidic soft water is neutralized to the same extent, the bicarbonate ions (HCO3 - ) is more adsorbed on the second weakly basic anion exchange resin 129b. Therefore, as will be described in detail later, in the circulation regeneration mode, more bicarbonate ions are released into the alkaline electrolyzed water, resulting in a decrease in the efficiency of generating acidic electrolyzed water and alkaline electrolyzed water by the electrolytic cell 107, or an increase in the amount of precipitates generated by the reaction of bicarbonate ions with hardness components in the alkaline electrolyzed water.

[0588] Therefore, by using multiple anion exchange resins, the amount of carbonate ions adsorbed on the weakly basic anion exchange resin can be reduced while extracting neutral soft water, compared to the case where the anion exchange resin is composed of a single type, thereby suppressing the influence of carbonate ions released in the circulation regeneration mode.

[0589] In the water softening device 101 , when the time period identified by the control unit 114 arrives, or when the water softening process exceeds a certain time, the water softening process is terminated and the water injection and regeneration process is executed.

[0590] <10.2 Water injection and regeneration process>

[0591] Reference Figure 14 and Figure 16 The column “Water injection and regeneration” explains the operation of the water softening device 101 when performing the water injection process and the operation of the regeneration device 106 when performing the regeneration process.

[0592] <10.2.1 Water injection process>

[0593] In the water softening device 101, as Figure 16 As shown in the "regeneration mode" of FIG, in the water injection process, the on-off valve 116 provided in the flow path 123 is opened in the state where the on-off valve 115 is closed. As a result, raw water containing hardness components flows in from the outside.

[0594] The inflowing raw water flows through the first recovery flow path 132 and is sent to the anode chamber of the electrolytic cell 107 , and also flows through the soft water tank 103 and the second recovery flow path 133 and is sent to the cathode chamber of the electrolytic cell 107 .

[0595] At this time, the flow path switching valve 121 is connected to allow water to be fed from the flow path 123 to the flow path 124 , and the on-off valve 117 is closed. The three-way valve 120 is connected to allow water to be fed from the flow path switching valve 122 to the alkaline electrolyzed water discharge flow path 138 .

[0596] Specifically, if Figure 14 As shown, in the water injection step, raw water is supplied from the inlet 102 through the flow path 123 and the first recovery flow path 132 to the anode chamber of the electrolytic cell 107 by the pressure of the raw water flowing in from the outside.

[0597] At this time, the flow path switching valve 121 is in a connection state in which water can be supplied from the flow path 123 to the flow path 124, but is not in a connection state in which water can be supplied to the first supply flow path 130. Therefore, the water supplied to the anode chamber of the electrolytic cell 107 flows through the first supply flow path 130 and does not flow into the soft water tank 103 from the first supply flow path 130. In addition, by providing the air extraction valve 151 (see Figure 14 ), the anode chamber of the electrolytic cell 107 and the first supply flow path 130 can be filled with raw water.

[0598] At the same time, the raw water is supplied from the inlet 102 to the cathode chamber of the electrolytic cell 107 through the flow path 123 , the soft water tank 103 , the flow path 124 , and the second recovery flow path 133 .

[0599] At this time, the three-way valve 120 is not in a connection state in which water can be supplied from the flow path 125 to the second neutralization tank 104 b , so that the water flowing through the flow path 124 can be prevented from flowing toward the neutralization tank 104 side.

[0600] <10.2.2 Regeneration process>

[0601] The water softening device 101 includes, as regeneration steps, a regeneration mode for discharging the alkaline electrolyzed water passed into the neutralization tank 104 and a circulation regeneration mode for circulating the alkaline electrolyzed water passed into the neutralization tank 104 in the neutralization tank circulation regeneration flow path 143 .

[0602] <10.2.2.1 Regeneration Mode>

[0603] In the regeneration mode, in the water softening device 101, as Figure 16 As shown in the "regeneration mode", the states of the on-off valves 116 to 119, the three-way valve 120, the flow path switching valves 121 and 122, the electrode 134, the first water pump 109 and the second water pump 110 are the same as those in the water injection process.

[0604] The on-off valve 116 provided in the flow path 123 is opened while the on-off valve 115 is closed. This allows raw water containing hardness components to flow in from the outside.

[0605] The inflowing raw water flows through the soft water tank 103 and the second recovery flow path 133 and is sent to the cathode chamber of the electrolytic cell 107. The raw water flows into the cathode chamber of the electrolytic cell 107 and is electrolyzed to generate alkaline electrolyzed water.

[0606] The generated alkaline electrolyzed water flows through the second supply flow path 131 , the second neutralization tank 104 b , and the alkaline electrolyzed water drain flow path 138 , and is discharged from the alkaline electrolyzed water drain port 113 .

[0607] At this time, the on-off valve 118 is opened, the flow path switching valve 122 is connected to allow water to be supplied from the second supply flow path 131 to the flow path 125 , and the three-way valve 120 is connected to allow water to be supplied from the flow path switching valve 122 to the alkaline electrolyzed water discharge flow path 138 .

[0608] Thus, in the regeneration mode, the alkaline electrolyzed water generated by the electrolytic cell 107 flows through the second neutralization tank 104 b , is used for regeneration of the second weakly basic anion exchange resin 129 b , and is then discharged from the alkaline electrolyzed water drain port 113 .

[0609] Thereby, the ion components adsorbed to the second weakly basic anion exchange resin 129 b are released into the alkaline electrolyzed water and then discharged as waste water.

[0610] Furthermore, by performing this regeneration mode for a short time (about 10% of the time required for the regeneration step) rather than a long time, ion components with a low exchange order among the ion components adsorbed on the second weakly basic anion exchange resin 129 b , particularly bicarbonate ions, can be preferentially discharged.

[0611] Among the anions contained in hard water, sulfate ions, nitrate ions, chloride ions, and bicarbonate ions are the main components. When the raw water, which is hard water, is passed through the weakly acidic cation exchange resin 128 and the weakly basic anion exchange resin 129 to perform the softening process, the weakly basic anion exchange resin 129 adsorbs not only chloride ions and sulfate ions, but also bicarbonate ions (HCO3 - ).

[0612] Since bicarbonate ions have a lower exchange order with the weakly basic anion exchange resin 129 than chloride ions and sulfate ions, they are less likely to be adsorbed on the weakly basic anion exchange resin 129 during the water softening process, but are easily released from the weakly basic anion exchange resin 129 during the regeneration mode. Therefore, when the bicarbonate ions flow through the first neutralization tank 104a and the second neutralization tank 104b, more sulfate ions and nitrate ions with a higher exchange order are adsorbed in the first neutralization tank 104a, which flows first, while more chloride ions and bicarbonate ions are adsorbed in the second neutralization tank 104b, which flows after the sulfate ions and nitrate ions decrease.

[0613] Furthermore, in the regeneration mode of the second weakly basic anion exchange resin 129b, most of the adsorbed bicarbonate ions are released in the early stages of the regeneration mode. In the case of a long regeneration period, the amount of bicarbonate ions released decreases in the middle and late stages of the regeneration period compared to the early stages. Therefore, by executing the regeneration mode for a short period of time, the amount of bicarbonate ions adsorbed in the second neutralization tank 104b can be significantly reduced.

[0614] It should be noted that although the regeneration mode may be performed for a long time, since the amount of discharged alkaline electrolyzed water increases, it is preferable to shift to the cyclic regeneration mode described later after bicarbonate ions are sufficiently released from the second weakly basic anion exchange resin 129 b .

[0615] Next, the effects of implementing the regeneration mode will be described.

[0616] When the raw water, which is hard water, is passed through the weakly acidic cation exchange resin 128 and the weakly basic anion exchange resin 129 to perform the water softening process, the weakly basic anion exchange resin 129 adsorbs not only chloride ions and sulfate ions, but also bicarbonate ions (HCO3 - ).

[0617] The adsorbed bicarbonate ions are released into the alkaline electrolyzed water during regeneration of the weakly basic anion exchange resin 129. The bicarbonate ions also diffuse into the acidic electrolyzed water through the diaphragm 150 in the electrolytic cell 107. That is, in the regeneration mode, bicarbonate ions are contained in both the alkaline electrolyzed water and the acidic electrolyzed water.

[0618] Bicarbonate ions have a buffering effect and react with hydrogen ions (H ＋ ) reacts to form carbonic acid (H2CO3) and hydroxide ions (OH - ) reacts to form carbonate ions (CO3 2- Therefore, if bicarbonate ions are present in the electrolyzed water, they consume hydrogen ions and hydroxide ions in the electrolyzed regenerated water, weakening the acidity or alkalinity of the electrolyzed water and thus reducing the efficiency of the regeneration mode.

[0619] Furthermore, carbonate ions generated by reacting with hydroxide ions in the alkaline electrolyzed water combine with calcium ions released from the weakly acidic cation exchange resin 128 and diffused into the acidic electrolyzed water, thereby precipitating calcium carbonate. Specifically, as the amount of bicarbonate ions adsorbed or released during the regeneration mode increases, calcium carbonate precipitation increases, which can promote clogging of the capture unit 108.

[0620] Therefore, it is required to suppress the amount of bicarbonate ion released in the cyclic regeneration mode described later. However, by executing the regeneration mode, the amount of bicarbonate ion released can be suppressed.

[0621] It should be noted that in the regeneration mode, the acidic electrolyzed water generated in the electrolytic cell 107 does not flow through the soft water tank 103 because there is no flow path for it to flow or circulate. Instead, it is retained in the anode chamber of the electrolytic cell 107 and the first supply flow path 130. However, the hydrogen ions (H ＋ ) is accumulated in the acidic electrolyzed water, that is, acidic electrolyzed water with a stronger acidity than when it is circulated can be generated. Thus, when the circulation regeneration mode described later starts, the acidic electrolyzed water can be circulated in the soft water tank 103 to be used for regeneration of the weakly acidic cation exchange resin 128.

[0622] Therefore, hydrogen ions generated in the anode chamber of the electrolytic cell 107 in the regeneration mode are not wastedly discharged, but can be used for regeneration of the weakly acidic cation exchange resin 128 .

[0623] In the water softening device 101 , when the time period identified by the control unit 114 arrives or when the water injection process and the regeneration mode exceed a certain time, the water injection process and the regeneration mode are terminated and the circulation regeneration mode is executed.

[0624] <10.2.2.2 Recycling Mode>

[0625] Next, refer to Figure 15 and Figure 16 In the column “In the Circulation Regeneration Mode”, the operation of the regeneration device 106 of the water softening device 101 in the circulation regeneration mode is described in sequence.

[0626] In the water softening device 101, if the soft water tank 103 filled with the weakly acidic cation exchange resin 128 is continuously used, the cation exchange capacity decreases or disappears. In other words, the hydrogen ions that are the functional groups of the cation exchange resin are all exchanged with calcium ions or magnesium ions that are the hardness components, and ion exchange becomes impossible.

[0627] If this condition occurs, hardness components are included in the treated water. Similarly, if the first and second neutralization tanks 104a and 104b filled with weakly basic anion exchange resin 129 continue to be used, the anion exchange capacity and neutralization performance will decrease or disappear. If this condition occurs, the acidic soft water flowing in from the soft water tank 103 will no longer be neutralized.

[0628] Therefore, in the water softening device 101, it is necessary to use the regeneration device 106 to perform a cyclic regeneration mode in the softening tank 103, the first neutralization tank 104a, and the second neutralization tank 104b. In the second embodiment, the control unit 114 determines the timing for executing the cyclic regeneration mode. When the time period determined by the control unit 114 arrives, or when the water filling and regeneration mode exceeds a certain time, the cyclic regeneration mode is executed.

[0629] In the circulation regeneration mode, close the switch valve 116, the switch valve 117 and the switch valve 119, open the switch valve 115 and the switch valve 118, set the three-way valve 120 to a connection state in which water can be supplied from the flow path 125 to the flow path switching valve 122, set the flow path switching valve 121 to a connection state in which water can be supplied from the first supply flow path 130 to the first recovery flow path 132, and set the flow path switching valve 122 to a connection state in which water can be supplied from the second supply flow path 131 to the flow path 125.

[0630] That is, the first neutralization tank 104a and the second neutralization tank 104b are in a state of communication and connection, and the drainage of the acidic electrolyzed water outlet 111 and the capture part drain outlet 112 is in a state of stopping. Figure 15 As shown, a soft water tank circulation and regeneration flow path 142 and a neutralization tank circulation and regeneration flow path 143 are formed respectively.

[0631] Then, when the first water supply pump 109 and the second water supply pump 110 are operated, the acidic electrolyzed water and the alkaline electrolyzed water in the electrolytic tank 107 circulate in the soft water tank circulation regeneration flow path 142 and the neutralization tank circulation regeneration flow path 143, respectively.

[0632] Furthermore, in electrolytic cell 107, current is applied so that anode 134a has a higher potential than cathode 134b (positive electrolysis). Consequently, during electrolysis, hydrogen ions are generated at anode 134a, producing acidic electrolyzed water near anode 134a. Meanwhile, hydroxide ions are generated at cathode 134b, producing alkaline electrolyzed water near cathode 134b.

[0633] The acidic electrolyzed water generated in the electrolytic cell 107 flows through the first supply flow path 130, is delivered to the soft water tank 103 via the flow path switching valve 121, and then flows through the weakly acidic cation exchange resin 128 within. Specifically, as the acidic electrolyzed water passes through the weakly acidic cation exchange resin 128, an ion exchange reaction occurs between the cations (hardness components) adsorbed on the weakly acidic cation exchange resin 128 and the hydrogen ions contained in the acidic electrolyzed water. This regenerates the weakly acidic cation exchange resin 128.

[0634] The acidic electrolyzed water flowing through the soft water tank 103 contains cations and flows into the first recovery flow path 132 . That is, the acidic electrolyzed water containing cations flowing through the weakly acidic cation exchange resin 128 is recovered to the electrolytic tank 107 via the first recovery flow path 132 .

[0635] In this manner, the acidic electrolyzed water flows through the soft water tank regeneration flow path 142 from the downstream side of the soft water tank 103, located furthest downstream of the raw water inlet. Specifically, in the regeneration mode, the acidic electrolyzed water flows through the weakly acidic cation exchange resin 128 in the soft water tank 103 from the downstream side, where the amount of hardness components adsorbed is low, toward the upstream side, where the amount of hardness components adsorbed is high. This prevents the hardness components from being reabsorbed onto the weakly acidic cation exchange resin 128 while the acidic electrolyzed water, which contains a large amount of hydrogen ions, flows into the soft water tank 103 and regenerates the weakly acidic cation exchange resin 128.

[0636] Therefore, it is possible to suppress a decrease in the efficiency of the regeneration mode and shorten the regeneration time. It should be noted that the "downstream side" refers to the downstream side in the flow path during the water softening process.

[0637] On the other hand, the alkaline electrolyzed water generated near the cathode 134b of the electrolytic cell 107 flows through the second supply flow path 131 and the capture unit 108, is transported to the second neutralization tank 104b via the flow path switching valve 122, and flows through the second weakly basic anion exchange resin 129b therein. The alkaline electrolyzed water that has flowed through the second neutralization tank 104b then flows through the flow path 125 and is transported to the first neutralization tank 104a, where it flows through the first weakly basic anion exchange resin 129a therein.

[0638] Specifically, by passing alkaline electrolyzed water through the weakly basic anion exchange resin 129, anions adsorbed to the weakly basic anion exchange resin 129 undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water, thereby regenerating the weakly basic anion exchange resin 129.

[0639] The alkaline electrolyzed water flowing through the first neutralization tank 104a contains anions and flows into the second recovery channel 133. That is, the alkaline electrolyzed water containing anions flowing through the weakly basic anion exchange resin 129 is recovered to the electrolytic tank 107 via the second recovery channel 133.

[0640] In this way, in the neutralization tank circulation regeneration flow path 143, alkaline electrolyzed water flows from the neutralization tank located at the most downstream of the raw water inlet, that is, the downstream side of the second neutralization tank 104b having the second weakly basic anion exchange resin 129b that adsorbs less anions than the neutralization tank on the upstream side, and flows into the downstream side of the first neutralization tank 104a located upstream and having the first weakly basic anion exchange resin 129a that adsorbs more anions than the second neutralization tank 104b.

[0641] That is, the neutralization tank circulation regeneration flow path 143 is a flow path that allows the alkaline electrolyzed water sent out from the electrolytic tank 107 to circulate in the second neutralization tank 104b, and then be sent to the first neutralization tank 104a through the flow path 125, so that it circulates in the first neutralization tank 104a and flows into the electrolytic tank 107 through the second recovery flow path 133.

[0642] Thus, in the circulation regeneration mode, alkaline electrolyzed water flows into the second neutralization tank 104b, which has a smaller amount of anions adsorbed than the first neutralization tank 104a, and the alkaline electrolyzed water containing anions is discharged from the second neutralization tank 104b to the first neutralization tank 104a. During the regeneration of the second weakly basic anion exchange resin 129b in the second neutralization tank 104b, the consumption of hydroxide ions in the alkaline electrolyzed water is less than that in the first neutralization tank 104a, so the decrease in hydroxide ion concentration can be suppressed compared to the regeneration of the first neutralization tank 104a.

[0643] Therefore, alkaline electrolyzed water containing a large amount of hydroxide ions flows into the first neutralization tank 104a, which can suppress the re-adsorption of anions in the first neutralization tank 104a. Therefore, a decrease in the efficiency of the regeneration mode can be suppressed, and the regeneration time can be shortened.

[0644] Furthermore, in the electrolytic cell 107, the hardness components released as cations from the soft water tank 103 during the regeneration mode react with the alkaline electrolyzed water, thereby generating precipitates. The precipitates contained in the alkaline electrolyzed water discharged from the electrolytic cell 107 are captured by the capture unit 108. This prevents the precipitates from flowing into the second neutralization tank 104b and accumulating.

[0645] By suppressing the accumulation of precipitates in this way, when the softening process is restarted after the circulation regeneration mode ends, the increase in the hardness of the soft water delivered from the second neutralization tank 104b caused by the ionization of the precipitates accumulated in the second neutralization tank 104b by reacting with the hydrogen ions contained in the water released from the first neutralization tank 104a can be suppressed.

[0646] The hardness component concentration of the regeneration water in the regeneration circulation path at the end of the regeneration mode varies greatly depending on the pH of the regeneration water (more fundamentally, the current value flowing in the electrolytic cell) and the type of the diaphragm 150 separating the electrodes 134 in the electrolytic cell.

[0647] This behavior varies greatly depending on the type of diaphragm 150 separating the electrodes 134 in the electrolytic cell 107. For example, when an anion exchange membrane is used as the diaphragm 150 of the electrolytic cell 107, the hardness component cannot move from the anode side to the cathode side of the electrolytic cell 107. Therefore, the inflow of the hardness component to the cathode side, that is, the neutralization tank regeneration flow path 143, becomes "0", and no precipitate is generated.

[0648] However, in this case, the hardness components desorbed from the weakly acidic cation exchange resin 128 in the recycle mode do not flow into the neutralization tank recycle flow path 143, but are instead concentrated entirely in the soft water tank recycle flow path 142. Consequently, the equilibrium of the ion exchange reaction between the hydrogen ions of the weakly acidic cation exchange resin 128 and the hardness components shifts toward adsorption of the hardness components onto the weakly acidic cation exchange resin 128. Consequently, regeneration of the weakly acidic cation exchange resin 128 becomes difficult. Therefore, in the water softening device 101, a porous membrane is used as the diaphragm 150 of the electrolytic cell 107.

[0649] In the water softening device 101, when the time period identified by the control unit 114 is reached, or when the circulation and regeneration mode exceeds a certain time (for example, 6 hours) or the circulation and regeneration time based on instruction information from the device user, the circulation and regeneration mode is terminated and the drainage process is performed.

[0650] It should be noted that when the user wants to obtain water in the circulation regeneration mode, by opening a faucet connected to the softening device 101, etc., raw water flows out from the inlet 102 through the bypass flow path 135 and the water intake 105. Therefore, the raw water can be used even without waiting for the circulation regeneration mode to end.

[0651] <10.3 Drainage process>

[0652] In the water softening device 101, when the regeneration mode ends, the process proceeds to the drainage step. Here, the drainage step is a step of draining the acidic electrolyzed water and alkaline electrolyzed water remaining in the regeneration flow path 142 of the softening tank and the regeneration flow path 143 of the neutralization tank.

[0653] Next, refer to Figure 16 The column “draining” explains the operation of the water softening device 101 when performing the drainage process.

[0654] In the water softening device 101, as Figure 16 As shown, in the drainage process (during drainage), the switch valve 116 is closed, the switch valve 115 and the switch valves 117 to 119 are opened, the three-way valve 120 is set to a connection state in which water can be supplied from the flow path 125 to the flow path switching valve 122, the flow path switching valve 121 is set to a connection state in which water can be supplied from the first supply flow path 130 to the first recovery flow path 132, and the flow path switching valve 122 is set to a connection state in which water can be supplied from the second supply flow path 131 to the flow path 125.

[0655] Thus, the soft water tank circulation regeneration flow path 142 and the neutralization tank circulation regeneration flow path 143 are formed respectively. In addition, by opening the switch valve 117 and the switch valve 119, the acidic electrolyzed water and the alkaline electrolyzed water can be discharged from the acidic electrolyzed water drain port 111 and the capture part drain port 112 respectively.

[0656] By performing the drainage process, when the softening process is restarted, the acidic electrolyzed water and alkaline electrolyzed water remaining in the soft water tank circulation regeneration flow path 142 and the neutralization tank circulation regeneration flow path 143 can be prevented from mixing with the raw water flowing in from the inlet 102 and being discharged from the water intake 105.

[0657] Furthermore, in water softening device 101, when the drainage process is completed, on-off valve 115 and on-off valves 117 to 119 are closed, on-off valve 116 is opened, three-way valve is connected to enable water to be fed from flow path 125 to flow path switching valve 122, flow path switching valve 121 is connected to enable water to be fed from flow path 123 to flow path 124, and flow path switching valve 122 is connected to enable water to be fed from flow path 125 to flow path 126, and the process then shifts to the water softening process. It should be noted that the drainage process may be terminated when a predetermined time has elapsed since the start of drainage processing.

[0658] As described above, in the water softening device 101 , the water softening step, the water injection and regeneration step, and the water discharge step are repeatedly performed.

[0659] The water softening device 101 is equipped with a second neutralization tank 104b filled with a second weakly basic anion exchange resin 129b having a larger acid dissociation constant (pKa) than the first weakly basic anion exchange resin 129a in the first neutralization tank 104a. This allows for the extraction of neutralized soft water, compared to a case where the neutralization tank 104 and the weakly basic anion exchange resin 129 are each composed of a single species, while also reducing the amount of bicarbonate ions adsorbed by the weakly basic anion exchange resin 129 and suppressing the effects of bicarbonate ions released during the regeneration mode.

[0660] Furthermore, in regeneration mode, alkaline electrolyzed water is circulated only through the second neutralization tank 104b, partially regenerating the second weakly basic anion exchange resin 129b. This minimizes the time and water volume required for regeneration mode, and allows the bicarbonate ions largely adsorbed by the second weakly basic anion exchange resin 129b to be released into the alkaline electrolyzed water in regeneration mode, rather than being released into the alkaline electrolyzed water in the subsequent cyclic regeneration mode. This reduces the effects of blockage of the capture unit 108 caused by the large-scale precipitation of calcium carbonate in cyclic regeneration mode, as well as the reduced regeneration efficiency caused by the buffering effect of bicarbonate ions.

[0661] As described above, according to the water softening device 101 of the second embodiment, the following effects can be obtained.

[0662] (1) The water softening device 101 includes a softening tank 103, a first neutralization tank 104a, a second neutralization tank 104b, an electrolytic tank 107, and a control unit 114. The softening tank 103 softens raw water containing hardness components using a weakly acidic cation exchange resin 128. The first neutralization tank 104a neutralizes the pH of the soft water passing through the softening tank 103 using a first weakly basic anion exchange resin 129a. The second neutralization tank 104b further neutralizes the pH of the soft water passing through the first neutralization tank 104a using a second weakly basic anion exchange resin 129b. Different types of weakly basic anion exchange resin are used for the first weakly basic anion exchange resin 129a and the second weakly basic anion exchange resin 129b, respectively. The second weakly basic anion exchange resin 129b is selected to have a larger acid dissociation constant (pKa) than the first weakly basic anion exchange resin 129a. The electrolytic tank 107 generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 128 of the soft water tank 103 and alkaline electrolyzed water for regenerating the first weakly basic anion exchange resin 129a of the first neutralization tank 104a and the second weakly basic anion exchange resin 129b of the second neutralization tank 104b.

[0663] According to this configuration, by providing the second neutralization tank 104b filled with the second weakly basic anion exchange resin 129b, even if the soft water flowing through the first neutralization tank 104a is not completely neutralized to neutrality, the soft water can be neutralized to neutrality by flowing the soft water through the second neutralization tank 104b. In addition, by making the filling amount of the second weakly basic anion exchange resin 129b as small as possible within the range where the pH of the soft water flowing into the second neutralization tank 104b becomes neutral, the generation of bicarbonate ions (HCO3) can be suppressed compared to the case of using only the second weakly basic anion exchange resin 129b. - ) adsorbed on the second weakly basic anion exchange resin 129b.

[0664] (2) The water softening device 101 is configured to allow the alkaline electrolyzed water flowing out of the electrolytic cell 107 to flow into the second neutralization tank 104 b in the regeneration mode and to be discharged through the alkaline electrolyzed water drainage channel 138 and the alkaline electrolyzed water drainage port 113 .

[0665] According to such a configuration, most of the bicarbonate ions adsorbed by the second weakly basic anion exchange resin 129b in the second neutralization tank 104b are released in the regeneration mode, which can significantly reduce the adsorbed bicarbonate ions. Therefore, the effects of the blockage of the capture portion 108 caused by the large amount of precipitation of calcium carbonate in the cyclic regeneration mode following the regeneration mode and the reduction in regeneration efficiency caused by the buffering effect of the bicarbonate ions can be reduced. In addition, by circulating the alkaline electrolyzed water only in the second weakly basic anion exchange resin 129b with a large amount of bicarbonate ion adsorption and draining it, the time and amount of water required in the regeneration mode can be reduced as much as possible.

[0666] The present disclosure has been described above based on the embodiments. These embodiments are merely illustrative, and those skilled in the art will appreciate that various modifications are possible for the combination of these components or processing steps, and such modifications are also within the scope of the present disclosure.

[0667] (Third embodiment)

[0668] In conventional water softening devices, a method of regenerating a cation exchange resin using acidic electrolyzed water generated by electrolysis is known as a method of regenerating the cation exchange resin without using common salt (for example, see Patent Document 1).

[0669] Weakly acidic cation exchange resins have protons at the ends of their functional groups and soften the raw water by exchanging hardness components (for example, calcium ions or magnesium ions) in the raw water for hydrogen ions.

[0670] Raw water softened with a weakly acidic cation exchange resin contains hydrogen ions and becomes acidic. The hydrogen ions in the softened water are adsorbed on the weakly basic anion exchange resin, thereby neutralizing the softened raw water.

[0671] In conventional water softening devices, a method of regenerating a weakly basic anion exchange resin using alkaline electrolyzed water generated by electrolysis is known (for example, see Patent Document 2).

[0672] In such conventional water softening devices, weakly acidic cation exchange resin and weakly basic anion exchange resin are regenerated using acidic electrolyzed water and alkaline electrolyzed water generated by electrolysis, respectively. However, resin regeneration requires a certain amount of time, thus prolonging the continuous electrolysis time.

[0673] Furthermore, as the regeneration process proceeds, the hardness of the water supplied to the electrolysis increases due to hardness components (eg, calcium ions and magnesium ions) released from the soft water tank, and the concentration of carbonate ions released from the neutralization tank also increases.

[0674] Therefore, in a system in which electrolyzed water with increased concentrations of hardness components and carbonate components is electrolyzed again and reused in a regeneration process, scale (e.g., calcium carbonate) derived from hardness components and carbonate components adheres to the electrode serving as the cathode as time passes from the start of the regeneration process.

[0675] As a result, the catalyst on the electrode surface is covered with scale, which eliminates the catalytically active area and reduces electrolytic performance. In addition, the flow of electrons between the anode and cathode is hindered, which increases the voltage between the anode and cathode and may shorten the life of the electrolytic cell.

[0676] As a conventional countermeasure against scale adhesion, a method has been used in which reverse electrolysis is performed to set the cathode to a higher potential relative to the anode than during positive electrolysis, thereby dissolving and removing scale adhered to the cathode during positive electrolysis.

[0677] However, when electrolyzing water that is prone to scale deposition, there are problems such as an increase in the frequency of reverse electrolysis treatment, accelerated electrode degradation, and reduced durability of the electrolytic cell.

[0678] The present disclosure provides a water softening device capable of suppressing electrode degradation during reverse electrolysis and improving the durability of an electrolytic cell.

[0679] The water softening device disclosed herein comprises: a control unit that controls a softening process for softening raw water containing hardness components and a regeneration process for an ion exchange resin used in the softening process; and an electrolytic cell having a first chamber and a second chamber separated from the first chamber by a diaphragm, which generates electrolyzed water used in the regeneration process. The electrolytic cell comprises a first main electrode disposed within the first chamber, a first sub-electrode disposed upstream of the first main electrode, a second main electrode disposed within the second chamber, and a second sub-electrode disposed upstream of the second main electrode. The control unit is configured to execute an electrolyzed water generation mode in which the electrolyzed water is generated using the first main electrode as an anode and the second main electrode as a cathode; and a main electrode cleaning mode in which the application of voltage to the first and second main electrodes is stopped, electrolysis is performed using the first sub-electrode as a cathode and the second sub-electrode as an anode, and the second main electrode is cleaned.

[0680] According to the present disclosure, it is possible to provide a water softening device that can suppress electrode degradation during reverse electrolysis and improve the durability of an electrolytic cell.

[0681] The following describes embodiments of the present disclosure with reference to the accompanying drawings. It should be noted that the following embodiments are examples of specific implementations of the present disclosure and do not limit the technical scope of the present disclosure. Furthermore, the figures described in the embodiments are schematic, and the sizes and thickness ratios of the components in the figures do not necessarily reflect actual dimensional ratios.

[0682] Reference Figure 17 A water softening device 201 according to a third embodiment of the present disclosure will be described.

[0683] Figure 17 2 is a conceptual diagram showing the structure of the water softening device 201 according to the third embodiment of the present disclosure. Figure 17 , each element of the water softening device 201 is conceptually shown.

[0684] (1. Overall composition)

[0685] The water softening device 201 produces neutral soft water from externally supplied raw water containing hardness. Neutral water not only includes a pH (hydrogen ion concentration index) of 7 but also includes pH values ​​between 6 and 8. Raw water refers to water (the water being treated) introduced into the device through inlet 202, such as tap water or well water.

[0686] Raw water contains hardness components (eg, calcium ions or magnesium ions). By performing a softening treatment using the water softening device 201 , neutral soft water with reduced hardness can be obtained, making it possible to use the soft water even in areas where the raw water hardness is high.

[0687] Specifically, if Figure 17 As shown, the water softening device 201 includes an inlet 202 , a softening tank, a neutralization tank, a water intake 207 , a regeneration device 208 , and a control unit 215 .

[0688] The water softening device 201 includes a drain port 213 , a capture unit drain port 214 , a plurality of on-off valves (on-off valves 218 to 223 ), and a plurality of flow path switching valves (flow path switching valves 224 to 227 ), details of which will be described later.

[0689] (2. Inlet and water intake)

[0690] The inlet 202 is connected to a raw water supply source and is an opening for introducing raw water into the water softening device 201 .

[0691] The water intake 207 is an opening for supplying softened water flowing through the water softening device 201 to the outside of the device. In the water softening device 201, the softened water can be taken out from the water intake 207 by utilizing the pressure of the raw water flowing in from the inlet 202.

[0692] In the softening process of the softening treatment in the softening device 201, raw water supplied from the outside flows through the inlet 202, the flow path 228, the first soft water tank 203, the flow path 229, the first neutralization tank 204, the flow path 230, the second soft water tank 205, the flow path 231, the second neutralization tank 206, the flow path 232 and the water intake 207 in sequence, and is discharged as neutral soft water.

[0693] (3. Soft water tank)

[0694] The softening tanks (first and second softening tanks 203 and 205) soften raw water containing hardness components using weakly acidic cation exchange resins. Specifically, the softening tanks exchange hardness-containing cations (at least one of calcium and magnesium ions) contained in the circulating water (raw water) with hydrogen ions, thereby reducing the hardness of the raw water and softening it.

[0695] The water softening device 201 of the third embodiment includes a first soft water tank 203 and a second soft water tank 205 as soft water tanks.

[0696] The first soft water tank 203 softens the raw water flowing in from the inlet 202. The first soft water tank 203 includes a flow path switching valve 224. Details of the flow path switching valve will be described later.

[0697] The second soft water tank 205 softens the water flowing through the first neutralization tank 204 described later. The second soft water tank 205 includes a flow path switching valve 226 .

[0698] The first soft water tank 203 and the second soft water tank 205 are filled with a weakly acidic cation exchange resin 233 .

[0699] The weakly acidic cation exchange resin 233 is an ion exchange resin having hydrogen ions at the ends of functional groups. The weakly acidic cation exchange resin 233 adsorbs cations (at least one of calcium ions and magnesium ions) as hardness components contained in the incoming raw water and releases hydrogen ions.

[0700] The soft water treated with the weakly acidic cation exchange resin 233 contains a large amount of hydrogen ions exchanged for hardness components. In other words, the soft water flowing out of the first soft water tank 203 and the second soft water tank 205 is acidified soft water containing a large amount of hydrogen ions (acidic soft water).

[0701] Since the functional groups of the weakly acidic cation exchange resin 233 are terminated with hydrogen ions, the weakly acidic cation exchange resin 233 can be regenerated using acidic electrolyzed water in the regeneration process described later. At this time, the cations that were introduced during the softening process and serve as hardness components are released from the weakly acidic cation exchange resin 233.

[0702] There are no particular limitations on the weakly acidic cation exchange resin 233, and a general-purpose resin can be used. For example, a resin having a carboxyl group (-COOH) as an exchange group can be used. In addition, a hydrogen ion (H ＋ ) can also be metal ions, or ammonium ions (NH4 ＋ ) and other cations.

[0703] (4. Neutralization tank)

[0704] The neutralization tanks (the first neutralization tank 204 and the second neutralization tank 206 ) neutralize the pH of the soft water (acidified soft water) containing hydrogen ions discharged from the soft water tank by the action of the weakly basic anion exchange resin 234 , thereby forming neutral soft water.

[0705] Specifically, the neutralization tank adsorbs hydrogen ions contained in the soft water from the soft water tank together with anions, thereby increasing the pH of the soft water to make the soft water neutral.

[0706] The water softening device 201 of the third embodiment includes a first neutralization tank 204 and a second neutralization tank 206 as neutralization tanks.

[0707] The first neutralization tank 204 neutralizes the acidic soft water flowing through the first soft water tank 203. The first neutralization tank 204 includes a flow path switching valve 225.

[0708] The second neutralization tank 206 neutralizes the acidic soft water flowing through the second soft water tank 205. The second neutralization tank 206 includes a flow path switching valve 227.

[0709] The first neutralization tank 204 and the second neutralization tank 206 are filled with a weakly basic anion exchange resin 234 .

[0710] The weakly basic anion exchange resin 234 neutralizes hydrogen ions contained in the water passed therethrough to generate neutral water. The weakly basic anion exchange resin 234 can be regenerated using alkaline electrolyzed water in a regeneration process described later.

[0711] The weakly basic anion exchange resin 234 is not particularly limited, and a general-purpose resin can be used. For example, a free base type resin can be mentioned.

[0712] (5. Regeneration device)

[0713] The regeneration device 208 is a device that regenerates the weakly acidic cation exchange resin 233 filled in the first soft water tank 203 and the second soft water tank 205 , and regenerates the weakly basic anion exchange resin 234 filled in the first neutralization tank 204 and the second neutralization tank 206 .

[0714] The regeneration device 208 includes an electrolytic cell 209 , a capture unit 210 , a first water supply pump 211 , and a second water supply pump 212 .

[0715] The first supply flow path 235, the second supply flow path 236, the first recovery flow path 237, and the second recovery flow path 238 of the regeneration device 208 are respectively connected to the second soft water tank 205, the second neutralization tank 206, the flow path 228, and the flow path 229. Details of each flow path will be described later.

[0716] It should be noted that the first supply flow path 235, the second supply flow path 236, the first recovery flow path 237, the second recovery flow path 238, the neutralization tank bypass flow path 242 and the soft water tank bypass flow path 244 form the soft water tank regeneration circulation flow path 239 and the neutralization tank regeneration circulation flow path 240 described later.

[0717] (5.1 Electrolyzer)

[0718] Figure 24 This is a conceptual diagram showing the structure of the electrolytic cell 209 of the water softening device 201.

[0719] like Figure 24 As shown, the electrolytic cell 209 includes a diaphragm 255 , a first chamber 256 , and a second chamber 257 . The first chamber 256 and the second chamber 257 are separated by the diaphragm 255 provided inside.

[0720] The diaphragm 255 is a membrane that divides the interior of the electrolytic cell 209 into a first chamber 256 and a second chamber 257. It can prevent mixing of the acidic electrolyzed water and the alkaline electrolyzed water by convection while allowing ion movement by electrophoresis.

[0721] The first chamber 256 includes a first main electrode 258 and a first sub-electrode 260 provided on the upstream side of the first main electrode 258 .

[0722] The first main electrode 258 is an electrode that forms a pair with the second main electrode 259 and serves as an anode during a regeneration process described later. The first main electrode 258 is provided downstream of the first sub-electrode 260 .

[0723] The first sub-electrode 260 is an electrode paired with the second sub-electrode 261 , and functions as a cathode when the electrolytic cell cleaning mode is executed under the condition A described later. The first sub-electrode 260 is provided upstream of the first main electrode 258 .

[0724] The second chamber 257 includes a second main electrode 259 and a second sub-electrode 261 provided on the upstream side of the second main electrode 259 .

[0725] The second main electrode 259 is an electrode that forms a pair with the first main electrode 258 and serves as a cathode during a regeneration process described later. The second main electrode 259 is provided downstream of the second sub-electrode 261 .

[0726] The second sub-electrode 261 is an electrode paired with the first sub-electrode 260 , and functions as an anode when the electrolytic cell cleaning mode is executed under the condition A described later. The second sub-electrode 261 is provided upstream of the second main electrode 259 .

[0727] In the electrolytic cell 209 , the first main electrode 258 and the second main electrode 259 provided inside the electrolytic cell electrolyze the incoming water (water supplied from the inlet 202 ), thereby generating acidic electrolyzed water and alkaline electrolyzed water, which are then discharged.

[0728] More specifically, at the first main electrode 258, which serves as the anode during electrolysis in the regeneration process, hydrogen ions are generated by electrolysis, producing acidic electrolyzed water. Furthermore, at the second main electrode 259, which serves as the cathode during electrolysis in the regeneration process, hydroxide ions are generated by electrolysis, producing alkaline electrolyzed water.

[0729] The first sub-electrode 260 and the second sub-electrode 261 can be used to dissolve and remove scale adhering to the second main electrode 259 serving as a cathode.

[0730] More specifically, the voltage applied to the first main electrode 258 and the second main electrode 259 is stopped, and the first auxiliary electrode 260 is used as a cathode and the second auxiliary electrode 261 is used as an anode to electrolyze the incoming water. As a result, the first chamber 256 is filled with alkaline electrolyzed water, and the second chamber 257 is filled with acidic electrolyzed water.

[0731] Therefore, the acidic electrolyzed water can dissolve and remove scale attached to the second main electrode 259. Then, the acidic electrolyzed water generated in the electrolytic tank 209 is supplied to the first soft water tank 203 and the second soft water tank 205 via the first supply flow path 235 and the neutralization tank bypass flow path 242.

[0732] In addition, the alkaline electrolyzed water produced in the electrolytic tank 209 is supplied to the first neutralization tank 204 and the second neutralization tank 206 via the second supply flow path 236 and the soft water tank bypass flow path 244 .

[0733] As will be described in detail later, the acidic electrolyzed water generated by the electrolytic cell 209 is used to regenerate the weakly acidic cation exchange resin 233 in the first soft water tank 203 and the second soft water tank 205, and the alkaline electrolyzed water generated by the electrolytic cell 209 is used to regenerate the weakly basic anion exchange resin 234 in the first neutralization tank 204 and the second neutralization tank 206.

[0734] The electrolytic cell 209 is configured such that the energization states of the first main electrode 258 , the second main electrode 259 , the first sub-electrode 260 , and the second sub-electrode 261 can be controlled by a control unit 215 described later.

[0735] (5.2 Water supply pump)

[0736] Return to Figure 17 The first water pump 211 is used to pump acidic electrolyzed water in the soft water tank regeneration circulation path 239 (refer to Figure 19 ) equipment circulating in the market.

[0737] The first water pump 211 is provided in the first recovery flow path 237 connecting the first soft water tank 203 and the electrolytic tank 209. This arrangement is used to facilitate the circulation of acidic electrolyzed water in the soft water tank regeneration circulation flow path 239 using only the first water pump 211.

[0738] The second water pump 212 is used to pump alkaline electrolyzed water through the neutralization tank regeneration circulation path 240 (see Figure 19 ) equipment circulating in the market.

[0739] The second water pump 212 is provided in the second recovery flow path 238 connecting the first neutralization tank 204 and the electrolytic tank 209. This arrangement is used to facilitate the circulation of alkaline electrolyzed water in the neutralization tank regeneration circulation flow path 240 using only the second water pump 212.

[0740] Furthermore, the first water pump 211 and the second water pump 212 are connected to a control unit 215 to be described later in a wireless or wired manner so as to be communicable.

[0741] (5.3 Capture Department)

[0742] The capturing unit 210 is provided in the second supply flow path 236 that connects the electrolytic tank 209 and the second neutralization tank 206 in communication with each other.

[0743] The capture unit 210 captures precipitates contained in the alkaline electrolyzed water sent from the electrolytic cell 209. The precipitates are reaction products generated by the reaction of hardness components as cations released from the first soft water tank 203 and the second soft water tank 205 during regeneration in the electrolytic cell 209 with the alkaline electrolyzed water.

[0744] More specifically, while water is electrolyzed in the electrolytic cell 209 , hardness components (eg, calcium ions and magnesium ions) released from the first and second soft water tanks 203 and 205 during the regeneration process move toward the cathode (second main electrode 259 ).

[0745] Since alkaline electrolyzed water is generated on the cathode side, the hardness component reacts with the alkaline electrolyzed water to form precipitates. For example, if the hardness component is calcium ions, mixing with the alkaline electrolyzed water causes a reaction to produce calcium carbonate or a reaction to produce calcium hydroxide.

[0746] The precipitates derived from these hardness components are captured as precipitates in the capture section 210 provided in the second supply flow path 236. By capturing the precipitates derived from the hardness components in the capture section 210, it is possible to suppress the precipitates from flowing into the second neutralization tank 206 and accumulating.

[0747] Therefore, when the softening treatment is restarted after the regeneration treatment is completed, the hardness of the soft water sent out from the second neutralization tank 206 can be suppressed, which is caused by the ionization of the precipitates accumulated in the second neutralization tank 206 by reacting with the hydrogen ions released from the first soft water tank 203 and the second soft water tank 205.

[0748] During the regeneration process, the alkaline electrolyzed water containing the precipitates from the hardness components passes through the capture unit 210 and flows through the second neutralization tank 206 and the first neutralization tank 204 , and then is electrolyzed again in the electrolytic tank 209 and supplied as alkaline electrolyzed water to regenerate the weakly basic anion exchange resin 234 .

[0749] In this case, the hardness components contained in the acidic electrolyzed water are reduced compared to a case where the capture unit 210 is not provided. In other words, by capturing the precipitates with the capture unit 210, the hardness of the acidic electrolyzed water is reduced, thereby reducing the hardness components flowing into the first soft water tank 203 and the second soft water tank 205, and suppressing a decrease in the regeneration efficiency of the weakly acidic cation exchange resin 233.

[0750] It should be noted that “the hardness components react” includes not only the case where all the hardness components react, but also the state where components that do not react or components that do not exceed the solubility product are included after the reaction.

[0751] The capture unit 210 may be of any form as long as it can separate the precipitate produced by the reaction of the hardness component with the alkaline electrolyzed water. For example, a cylindrical filter, a filter layer using a granular filter material, a cyclone-type solid-liquid separator, or a hollow fiber membrane may be used.

[0752] A cartridge filter is a commonly used mechanism for capturing unit 210. The cartridge filter may be a depth filter such as a wire wound filter, a surface filter such as a pleated filter or a membrane filter, or a combination thereof.

[0753] Wire-wound filters are compatible with particle sizes ranging from 1 to 150 microns and are primarily used as pre-filters. Pleated and membrane filters are available that accommodate a wide range of particle sizes, from approximately 0.03 to 100 microns. However, when implementing the present disclosure, to reduce the likelihood of filter clogging, it is preferable to use a filter with a precision of 0.5 microns or greater (a filter corresponding to the particle size). Furthermore, to ensure adequate precipitate capture, it is preferable to use a filter with a precision of 1.5 microns or less (a filter corresponding to the particle size).

[0754] In the capture unit 210 , alkaline electrolyzed water flows during the regeneration process described later, and acidic electrolyzed water flows during the cleaning process. Therefore, the material of the cartridge filter is preferably a material having high corrosion resistance to acids and alkalis (eg, polypropylene).

[0755] The purpose of the granular filter material used in the filtration layer is to capture and remove hardness components. However, depending on the presence of particles with surface potential such as those adsorbed on the granular filter material or ions in the raw water, it can also remove particles with a particle size of approximately 1 to 10 microns or color components.

[0756] Granular filter media can be granular fiber filter media, such as filter sand, suitable for removing the target material. Granular filter media can be made from materials that settle in water and are hard enough to resist deformation under pressure, such as sand, anthracite, garnet, ceramic, granular activated carbon, hydrated iron oxide, or manganese sand. For example, materials with a particle size of 0.3 to 5.0 mm and a uniformity coefficient of 1.2 to 2.0 can be used.

[0757] In addition, a multilayer filtration method that uses a mixture of multiple filter materials with different specific gravities is a method in which particles of different sizes are stacked in layers starting from the smallest particle and then stacked up in order from the bottom to form a filtering layer. In a multilayer filtration method, particles with a large specific gravity and a small size are usually mixed with particles with a large specific gravity to form a multilayer structure. Compared to methods using a single type of filter material, multilayer filtration methods have the advantages of high filtration efficiency per unit volume and low head loss, and are therefore preferred.

[0758] As the granular filter material, for example, 0.3 mm garnet, 0.6 mm sand, and 1.0 mm anthracite are mixed at a ratio of 2:1:1. The mixing ratio or particle size is preferably adjusted according to the particle characteristics of the suspended matter.

[0759] The capturing unit 210 includes an on-off valve 222 and a capturing unit drain port 214 .

[0760] The on-off valve 222 is provided at the bottom of the capture unit 210 and controls the drainage of the capture unit 210. By opening the on-off valve 222, the water in the capture unit 210 can be drained from the capture unit drain port 214 to the outside of the device.

[0761] The capture unit drain port 214 is an opening for draining water from the capture unit 210 to the outside of the device. By opening the on-off valve 222 provided upstream of the capture unit drain port 214, the water in the capture unit 210 can be drained from the capture unit drain port 214 to the outside of the device.

[0762] (6. On-off valve and flow path switching valve)

[0763] A plurality of on-off valves (on-off valves 218 to 223 ) are provided in each flow path, respectively, and switch between an “open” state and a “closed” state in each flow path.

[0764] The plurality of on-off valves (on-off valve 218 , on-off valve 219 , on-off valve 221 , and on-off valve 223 ) start or stop the flow of water to each flow path by opening and closing the valves.

[0765] The on-off valve 220 and the on-off valve 222 are opened during the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process described later, and the regeneration circulating water is discharged outside the device.

[0766] A plurality of flow path switching valves (flow path switching valves 224 to 227 ) are provided in the first soft water tank 203 , the second soft water tank 205 , the first neutralization tank 204 , and the second neutralization tank 206 , respectively.

[0767] Each of the multiple flow path switching valves has three openings, the first opening is an inflow and outflow port that allows water to flow in and out, the second opening is an inflow port that functions as an inflow port rather than an outflow port, and the third opening is an outflow port that functions as an outflow port rather than an inflow port.

[0768] The inlet and outlet ports of the multiple flow path switching valves are always "open." Depending on the direction of water flow, when either the inlet or outlet is "open," the other outlet is "closed." The provision of flow path switching valves 224-227 reduces the number of on-off valves required for each flow path within the water softening device 201, thereby reducing the cost of the water softening device 201.

[0769] Furthermore, the plurality of on-off valves (on-off valves 218 to 223 ) and the plurality of flow path switching valves (flow path switching valves 224 to 227 ) are communicably connected to a control unit 215 described later via wireless or wired communication.

[0770] (7. Drain outlet)

[0771] The drain port 213 is an opening provided at the end of the drain flow path 254 and is an opening for draining water in the device to the outside of the device during the regeneration path cleaning process and the electrolytic cell cleaning process.

[0772] An on-off valve 220 is provided upstream of the drain port 213 , and water can be discharged from the drain port 213 by opening the on-off valve 220 .

[0773] (8. Control Department)

[0774] The control unit controls execution of each of the water softening step, the regeneration step, the regeneration flow path cleaning step, the electrolytic cell cleaning step, and the capturing unit cleaning step, as well as switching between the steps.

[0775] Specifically, the control of switching between each process means: the control unit 215 controls the switching from the softening process to the regeneration process, the switching from the regeneration process to the regeneration flow path cleaning process, the switching from the regeneration flow path cleaning process to the electrolytic cell cleaning process, the switching from the electrolytic cell cleaning process to the capture part cleaning process, and the switching from the capture part cleaning process to the softening process, etc.

[0776] Furthermore, the control unit 215 controls the on-off valve 220 and the on-off valve 222 to control drainage during the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process.

[0777] Furthermore, the control unit 215 controls the flow path switching valves 224 to 227 , the on-off valve 218 , the on-off valve 219 , the on-off valve 221 , and the on-off valve 223 to switch the respective flow paths.

[0778] (9.Flow path)

[0779] Flow path 253 connects inlet 202 and water intake 207, and is provided with an on-off valve 218. Users of water softening device 201 can obtain raw water from water intake 207 even when any of the following processes, including the regeneration process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process, are performed through flow path 253.

[0780] (10. Water softening flow path)

[0781] Reference Figure 18 The softening flow path 243 formed during the water softening process of the water softening device 201 will be described.

[0782] Figure 18 It is a diagram showing the water softening flow path 243 of the water softening device 201 .

[0783] Softening flow path 243 ( Figure 18 The oblique line arrows 243 are the flow paths for softening raw water. The raw water flowing through the softening flow path 243 becomes neutral soft water and is discharged from the water intake port 207 to the outside of the device.

[0784] The softening flow path 243 is formed by the inlet 202 , the flow path 228 , the first softening tank 203 , the flow path 229 , the first neutralization tank 204 , the flow path 230 , the second softening tank 205 , the flow path 231 , the second neutralization tank 206 , the flow path 232 , and the water intake 207 .

[0785] The flow path 228 is a flow path connected from the inlet 202 to the first soft water tank 203. That is, the flow path 228 is a flow path that guides the raw water containing hardness components from the inlet 202 to the first soft water tank 203.

[0786] The flow path 229 is a flow path connecting the first soft water tank 203 to the first neutralization tank 204. That is, the flow path 229 is a flow path that guides the water softened in the first soft water tank 203 to the first neutralization tank 204.

[0787] The flow path 230 is a flow path connected from the first neutralization tank 204 to the second soft water tank 205. In other words, the flow path 230 is a flow path that guides the water neutralized in the first neutralization tank 204 to the second soft water tank 205.

[0788] The flow path 231 is a flow path connecting the second soft water tank 205 to the second neutralization tank 206. That is, the flow path 231 is a flow path that guides the water softened in the second soft water tank 205 to the second neutralization tank 206.

[0789] The flow path 232 is a flow path connected to the water intake port 207 from the second neutralization tank 206. In other words, the flow path 232 is a flow path that guides softened raw water from the second neutralization tank 206 to the water intake port 207.

[0790] like Figure 18 As shown, an on-off valve 219 is provided in the flow path 228 on the downstream side of the inlet 202 and the upstream side of the first soft water tank 203. In addition, an on-off valve 218 is provided in the flow path 253.

[0791] By closing the on-off valve 218 and opening the on-off valve 219, the first soft water tank 203 is connected to the inlet 202. Furthermore, the flow path switching valve 224 is switched to connect the first soft water tank 203 to the first neutralization tank 204, the flow path switching valve 225 is switched to connect the first neutralization tank 204 to the second soft water tank 205, the flow path switching valve 226 is switched to connect the second soft water tank 205 to the second neutralization tank 206, and the flow path switching valve 227 is switched to connect the second neutralization tank 206 to the water intake 207.

[0792] Thus, a softening flow path 243 is formed that communicates from the inlet 202 to the flow path 228, the first soft water tank 203, the flow path 229, the first neutralization tank 204, the flow path 230, the second soft water tank 205, the flow path 231, the second neutralization tank 206, the flow path 232 and the water intake 207.

[0793] At this time, the on-off valve 220 , the on-off valve 221 , and the on-off valve 223 are closed.

[0794] (11. Regeneration circulation flow path)

[0795] Next, refer to Figure 19 The softening tank regeneration circulation flow path 239 and the neutralization tank regeneration circulation flow path 240 formed during the regeneration process of the water softening device 201 will be described.

[0796] Figure 19 It is a diagram showing the softening tank regeneration circulation flow path 239 and the neutralization tank regeneration circulation flow path 240 of the water softening device 201.

[0797] First, the soft water tank regeneration circulation flow path 239 will be described.

[0798] The soft water tank regeneration circulation flow path 239 is a flow path for regenerating the first soft water tank 203 and the second soft water tank 205 by circulating acidic electrolyzed water during the regeneration process. Figure 19 Indicated by (white arrows) is a flow path in which water delivered by the first water delivery pump 211 circulates through the electrolytic tank 209 , the second soft water tank 205 , and the first soft water tank 203 and returns to the electrolytic tank 209 .

[0799] Specifically, the soft water tank regeneration circulation flow path 239 is composed of the first supply flow path 235 connecting the electrolytic tank 209 , the second soft water tank 205 , the first soft water tank 203 and the first water supply pump 211 , the neutralization tank bypass flow path 242 and the first recovery flow path 237 .

[0800] The first supply flow path 235 is a flow path that communicates from the downstream side of the electrolytic cell 209 to the downstream side of the second soft water tank 205 , and is a flow path for supplying acidic electrolyzed water from the electrolytic cell 209 to the second soft water tank 205 .

[0801] The neutralization tank bypass flow path 242 is a flow path that bypasses the first neutralization tank 204 and connects from the upstream side of the second soft water tank 205 to the downstream side of the first soft water tank 203 . It is a flow path for supplying acidic electrolyzed water from the second soft water tank 205 to the first soft water tank 203 .

[0802] First recovery flow path 237 is a flow path connected from the upstream side of first soft water tank 203 to electrolytic tank 209, and is a flow path for recovering the acidic electrolyzed water containing hardness components that has passed through first soft water tank 203 and second soft water tank 205 to electrolytic tank 209. A first water supply pump 211 is provided in first recovery flow path 237.

[0803] Furthermore, the soft water tank regeneration circulation flow path 239 is a flow path that directs the acidic electrolyzed water fed from the electrolytic tank 209 into the first soft water tank 203 and the second soft water tank 205 from their respective downstream sides, and then flows out from the upstream side of the soft water tank, where the amount of hardness components adsorbed is greater than that on the downstream side. It should be noted that the downstream side (or upstream side) in the soft water tank and the neutralization tank refers to the downstream side (or upstream side) of the flow path during the softening treatment.

[0804] Next, the neutralization tank regeneration circulation flow path 240 will be described.

[0805] The neutralization tank regeneration circulation flow path 240 is a flow path for regenerating the first neutralization tank 204 and the second neutralization tank 206 by circulating alkaline electrolyzed water during the regeneration process. Figure 19 Indicated by (black arrows) is a flow path in which water delivered by the second water delivery pump 212 circulates through the electrolytic tank 209 , the second neutralization tank 206 , and the first neutralization tank 204 and returns to the electrolytic tank 209 .

[0806] Specifically, the neutralization tank regeneration circulation flow path 240 is composed of the second supply flow path 236 connecting the electrolytic tank 209, the second neutralization tank 206, the first neutralization tank 204 and the second water supply pump 212, the soft water tank bypass flow path 244 and the second recovery flow path 238.

[0807] The second supply flow path 236 is a flow path that communicates from the downstream side of the electrolytic tank 209 to the downstream side of the second neutralization tank 206 , and is a flow path for supplying alkaline electrolyzed water from the electrolytic tank 209 to the second neutralization tank 206 .

[0808] The second supply flow path 236 is provided with a capture unit 210 , an on-off valve 221 , and an on-off valve 223 .

[0809] The soft water tank bypass flow path 244 is a flow path that bypasses the second soft water tank 205 and is connected from the upstream side of the second neutralization tank 206 to the downstream side of the first neutralization tank 204 . It is a flow path for supplying alkaline electrolyzed water from the second neutralization tank 206 to the first neutralization tank 204 .

[0810] The second recovery flow path 238 is a flow path connected to the electrolytic cell 209 from the upstream side of the first neutralization tank 204, and is a flow path for recovering the alkaline electrolyzed water that has passed through the first neutralization tank 204 and the second neutralization tank 206 to the electrolytic cell 209. The second water supply pump 212 is provided in the second recovery flow path 238.

[0811] (12. Regeneration flow path and cleaning flow path)

[0812] Next, refer to Figure 20 The regeneration flow path cleaning flow path 245 formed during the regeneration flow path cleaning step of the water softening device 201 will be described.

[0813] Figure 20 It is a diagram showing the regeneration flow path cleaning flow path 245 of the water softening device 201.

[0814] The regeneration flow path cleaning flow path 245 is a flow path that, during the regeneration flow path cleaning process described later, allows high-hardness water remaining in the flow path to be discharged outside the device without flowing into the first neutralization tank 204 and the second neutralization tank 206. The regeneration flow path cleaning flow path 245 is configured to include a first drain flow path 246 and a second drain flow path 247.

[0815] like Figure 20 As shown by (white arrows), the first drain flow path 246 is composed of flow paths connecting the first water pump 211 , the electrolytic cell 209 , the on-off valve 220 , and the drain port 213 from the inlet 202 .

[0816] Specifically, the first drain flow path 246 allows the raw water flowing in from the inlet 202 to flow through the flow path 228 , the first recovery flow path 237 , the first water pump 211 , the electrolytic cell 209 , the drain flow path 254 , the on-off valve 220 , and the drain port 213 in this order.

[0817] The drain flow path 254 is a flow path connected to the first supply flow path 235 at one end and is a flow path connected to the drain port 213 at the other end.

[0818] The drain flow path 254 is provided with an on-off valve 220 . By opening the on-off valve 220 , water in the flow path can be discharged outside the device. By closing the on-off valve 220 , drainage from the drain port 213 can be stopped.

[0819] like Figure 20As shown by (black arrows), the second drain flow path 247 is composed of flow paths that are connected from the inlet 202 to the first soft water tank 203 , the second soft water tank 205 , the on-off valve 220 , and the drain port 213 .

[0820] Specifically, the second drain flow path 247 allows the raw water flowing in from the inlet 202 to flow through the flow path 228, the first soft water tank 203, the neutralization tank bypass flow path 242, the second soft water tank 205, the first supply flow path 235, the on-off valve 220, and the drain port 213 in this order.

[0821] It should be noted that the flow rate of water flowing through the second drain flow path 247 is preferably controlled to be greater than the flow rate of water flowing through the first drain flow path 246. This allows the high-hardness water in the second drain flow path 247, which includes the softening tank used during the water softening process, to be preferentially replaced with raw water. This can suppress the influence of high-hardness water at the start of the water softening process.

[0822] (13. Electrolytic cell cleaning flow path)

[0823] Next, refer to Figure 21 The electrolytic cell cleaning flow path 249 formed during the electrolytic cell cleaning step of the water softening device 201 will be described.

[0824] Figure 21 This is a diagram showing the electrolytic cell cleaning flow path 249 of the water softening device 201.

[0825] The electrolytic tank cleaning flow path 249 is a flow path for removing precipitates caused by hardness components in the electrolytic tank 209 and the neutralization tank regeneration circulation flow path 240 during the electrolytic tank cleaning step described later.

[0826] The electrolytic cell cleaning flow path 249 is configured to include a first drain flow path 246 and a third drain flow path 250 .

[0827] like Figure 21 As shown by the black arrows, the third drainage flow path 250 is composed of flow paths that communicate with the first soft water tank 203 , the second water pump 212 , the electrolytic cell 209 , the on-off valve 221 , the capture unit 210 , the on-off valve 222 , and the capture unit drain port 214 .

[0828] Specifically, the third drainage flow path 250 is a flow path that allows the raw water flowing in from the inlet 202 to flow through the flow path 228, the first soft water tank 203, the second recovery flow path 238, the second water supply pump 212, the electrolytic cell 209, the second supply flow path 236, the switch valve 221, the capture part 210 and the switch valve 222 in sequence, and is discharged to the outside of the device from the capture part drain port 214.

[0829] More specifically, in third drain flow path 250, raw water flowing from inlet 202 flows through flow path 228 into first soft water tank 203, generating acidic soft water. The generated acidic soft water then flows through second recovery flow path 238 and into electrolytic cell 209 via second water pump 212. The acidic soft water then flows through second supply flow path 236, sequentially through on-off valve 221, capture unit 210, and on-off valve 222. The precipitate in capture unit 210 is dissolved in the acidic soft water and discharged from capture unit drain port 214 to the outside of the device.

[0830] (14. Capture unit cleaning flow path)

[0831] Next, refer to Figure 22 The capturing unit cleaning flow path 251 formed during the capturing unit cleaning step of the water softening device 201 will be described.

[0832] Figure 22 This is a diagram showing the capture unit cleaning flow path 251 of the water softening device 201.

[0833] The capturing portion cleaning flow path 251 is a flow path for removing precipitates derived from hardness components precipitated in the capturing portion 210 during a capturing portion cleaning step described later.

[0834] The capturing portion cleaning flow path 251 is configured to include the fourth drain flow path 252 .

[0835] like Figure 22 As shown, the capture part cleaning flow path 251 is composed of flow paths connected from the inlet 202 to the first soft water tank 203, the first neutralization tank 204, the second soft water tank 205, the second neutralization tank 206, the capture part 210 and the capture part drain port 214.

[0836] Specifically, the capture section cleaning flow path 251 is a flow path that allows the raw water flowing in from the inlet 202 to flow in sequence through the flow path 228, the first soft water tank 203, the flow path 229, the first neutralization tank 204, the flow path 230, the second soft water tank 205, the flow path 231, the second neutralization tank 206, the second supply flow path 236, the switch valve 223, the capture section 210 and the switch valve 222, and is discharged to the outside of the device from the capture section drain port 214.

[0837] The above is the structure of the water softening device 201.

[0838] Next, the operation of the water softening device 201 will be described.

[0839] (15. Water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process and capture unit cleaning process)

[0840] Next, refer to Figure 23The water softening step, regeneration step, regeneration flow path cleaning step, electrolytic cell cleaning step, and capture unit cleaning step of the water softening device 201 will be described.

[0841] Figure 23 It is a figure which shows the state of each component when the water softening device 201 is operating.

[0842] In the water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process and capture part cleaning process, as Figure 23 As shown, the control unit 215 switches the on-off valves 218 to 223 , the flow path switching valves 224 to 227 , the electrodes of the electrolytic cell 209 , and the first and second water pumps 211 and 212 to control them so as to achieve their respective flow states.

[0843] Here, Figure 23 "ON" in the columns indicates that the corresponding switch valve is "open," the electrodes are energized, and the corresponding water pump is operating. Blank columns indicate that the corresponding switch valve is "closed," the electrodes are not energized, and the corresponding water pump is stopped.

[0844] in addition, Figure 23 The phrase "from (component a's number) to (component b's number)" indicates that the corresponding flow path switching valve is connected to the flow path in the direction of water flow from component a to component b. For example, flow path switching valve 224 in the water softening process connects the flow paths so that water can flow from flow path 228 to flow path 229.

[0845] in addition, Figure 23 The phrase "toward (number of component c)" indicates that the corresponding flow path switching valve is connected to the flow path in a direction that could potentially supply water to component c. In this state, although the flow path is connected, the environment is such that water is unlikely to flow into or out of the soft water tank or neutralization tank where the corresponding flow path switching valve is installed, making water delivery from the corresponding flow path switching valve extremely unlikely.

[0846] (15.1 Water Softening Process)

[0847] Reference Figure 18 and Figure 23 The column “during water softening” explains the operation of the water softening device 201 when performing the water softening process.

[0848] In the water softening device 201, as Figure 23 As shown, in the water softening process, the on-off valve 219 provided in the flow path 228 is opened while the on-off valve 218 is closed. This allows raw water containing hardness components to flow in from the outside.

[0849] The inflowing raw water flows sequentially through the first soft water tank 203 , the first neutralization tank 204 , the second soft water tank 205 , and the second neutralization tank 206 . Therefore, the softening device 201 can take out softened water (neutral soft water) from the water intake 207 .

[0850] At this time, the flow path switching valve 224 becomes a connection state capable of supplying water from flow path 228 to flow path 229, the flow path switching valve 225 becomes a connection state capable of supplying water from flow path 229 to flow path 230, the flow path switching valve 226 becomes a connection state capable of supplying water from flow path 230 to flow path 231, and the flow path switching valve 227 becomes a connection state capable of supplying water from flow path 231 to flow path 232.

[0851] The on-off valves 220 to 223 are all in a closed state. In addition, the electrodes of the electrolytic cell 209, the first water pump 211, and the second water pump 212 are also stopped.

[0852] Specifically, if Figure 18 As shown, in the water softening step, raw water is supplied from the inlet 202 through the flow path 228 to the first soft water tank 203 by the pressure of raw water flowing in from the outside.

[0853] The raw water supplied to the first soft water tank 203 flows through the weakly acidic cation exchange resin 233 contained within the first soft water tank 203. During this process, the cations in the raw water, which constitute the hardness component, are adsorbed by the weakly acidic cation exchange resin 233, releasing hydrogen ions (ion exchange). The raw water is then softened by removing the cations.

[0854] Softened water contains a large amount of hydrogen ions released in exchange for hardness components, resulting in acidification and a low pH (first soft water). Water containing a large amount of permanent hardness components (e.g., sulfates such as calcium sulfate or chlorides such as magnesium chloride) tends to have a lower pH during softening compared to water containing a large amount of temporary hardness components (e.g., carbonates such as calcium carbonate). Softening is difficult when the pH is lowered, so the water flowing through the first soft water tank 203 is passed into the first neutralization tank 204 for neutralization.

[0855] The water softened in the first soft water tank 203 flows through the flow path 229 via the flow path switching valve 224 provided in the first soft water tank 203 , and flows into the first neutralization tank 204 .

[0856] In the first neutralization tank 204, the weakly basic anion exchange resin 234 adsorbs hydrogen ions contained in the softened water. Specifically, as hydrogen ions are removed from the water softened in the first softening tank 203, the lowered pH rises and is neutralized. Therefore, compared to directly softening the water softened in the first softening tank 203 in the second softening tank 205, the softening process in the second softening tank 205 is facilitated.

[0857] The water neutralized in the first neutralization tank 204 (neutralized first soft water) flows through the flow path 230 via the flow path switching valve 225 provided in the first neutralization tank 204 , and flows into the second soft water tank 205 .

[0858] In the second soft water tank 205, weakly acidic cation exchange resin 233 adsorbs cations, which are hardness components, and releases hydrogen ions. The second soft water tank 205 exchanges the hardness components that were not removed in the first soft water tank 203 for hydrogen ions contained in the weakly acidic cation exchange resin 233. In other words, the water flowing into the second soft water tank 205 is further softened, becoming soft water (second soft water).

[0859] The second soft water flows through flow path 231 via flow path switching valve 226 installed in second soft water tank 205 and into second neutralization tank 206. In second neutralization tank 206, weakly basic anion exchange resin 234 adsorbs hydrogen ions contained in the incoming second soft water. This removal of hydrogen ions from the second soft water raises the previously lowered pH, resulting in neutral soft water suitable for domestic use (neutralized second soft water). The neutralized second soft water then flows through flow path switching valve 227 installed in second neutralization tank 206 and can be withdrawn from water intake 207.

[0860] Specifically, during the water softening process, raw water flows sequentially through the first softening tank 203, the first neutralization tank 204, the second softening tank 205, and the second neutralization tank 206. Thus, raw water containing hardness components flows out of the first softening tank 203 before its pH is lowered by the softening process in the first softening tank 203, is neutralized in the first neutralization tank 204, softened in the second softening tank 205, and neutralized in the second neutralization tank 206.

[0861] Therefore, compared to a case where the softening tank and the neutralization tank are configured separately, a decrease in the pH of the water flowing through the softening tank, i.e., an increase in acidity, can be suppressed. This facilitates the exchange of hardness components with hydrogen ions held by the weakly acidic cation exchange resin 233 in the softening tank (particularly the second softening tank 205). Consequently, the softening performance can be improved.

[0862] Then, in the water softening device 201, when the time period identified by the control unit 215 comes or when the amount of water subjected to the softening process exceeds a certain amount, the softening process is terminated and the regeneration process is executed.

[0863] (15.2 Regeneration process)

[0864] Next, refer to Figure 19 and Figure 23 In the "Regeneration" column, the operation of the regeneration process performed by the regeneration device 208 of the water softening device 201 is described in sequence.

[0865] In the water softening device 201, if the first and second softening tanks 203 and 205 filled with weakly acidic cation exchange resin 233 are used continuously, their cation exchange capacity decreases or disappears. Specifically, the hydrogen ions that form the functional groups of the cation exchange resin are all exchanged for calcium ions or magnesium ions, which are hardness components, and ion exchange becomes impossible.

[0866] Even before all hydrogen ions are exchanged for hardness components, as the number of hydrogen ions decreases, the ion exchange reaction becomes difficult to occur, thereby reducing the water softening performance. If this state is reached, hardness components will be contained in the treated water.

[0867] Therefore, in the water softening device 201 , it is necessary to perform regeneration processing on the first soft water tank 203 , the second soft water tank 205 , the first neutralization tank 204 , and the second neutralization tank 206 using the regeneration device 208 .

[0868] During the regeneration process, the on-off valves 219, 220, and 222 are closed, and the on-off valves 218, 221, and 223 are opened. Furthermore, the flow path switching valve 224 is set to a connection state in which water can be fed from the neutralization tank bypass flow path 242 to the first recovery flow path 237. The flow path switching valve 225 is set to a connection state in which water can be fed from the soft water tank bypass flow path 244 to the second recovery flow path 238. The flow path switching valve 226 is set to a connection state in which water can be fed from the first supply flow path 235 to the neutralization tank bypass flow path 242. The flow path switching valve 227 is set to a connection state in which water can be fed from the second supply flow path 236 to the soft water tank bypass flow path 244.

[0869] That is, the first soft water tank 203 and the second soft water tank 205 are connected, the first neutralization tank 204 and the second neutralization tank 206 are connected, and the drainage of the drain outlet 213 and the capture part drain outlet 214 is stopped. Figure 19 As shown, a soft water tank regeneration circulation flow path 239 and a neutralization tank regeneration circulation flow path 240 are formed respectively.

[0870] Then, when the first water supply pump 211 and the second water supply pump 212 are operated, the acidic electrolyzed water and the alkaline electrolyzed water in the electrolytic tank 209 circulate in the soft water tank regeneration circulation flow path 239 and the neutralization tank regeneration circulation flow path 240, respectively.

[0871] Furthermore, in the electrolytic cell 209, current is applied so that the first main electrode 258 has a higher potential than the second main electrode 259 (positive electrolysis). This electrolyzed water generation mode generates hydrogen ions at the anode during electrolysis, producing acidic electrolyzed water near the anode. Meanwhile, hydroxide ions are generated at the cathode, producing alkaline electrolyzed water near the cathode.

[0872] The acidic electrolyzed water generated in the electrolytic cell 209 flows through the first supply flow path 235, is transported to the second soft water tank 205 via the flow path switching valve 226, and flows through the weakly acidic cation exchange resin 233 therein. The acidic electrolyzed water that has flowed through the second soft water tank 205 then flows through the neutralization tank bypass flow path 242, is transported to the first soft water tank 203 via the flow path switching valve 224, and flows through the weakly acidic cation exchange resin 233 therein.

[0873] Specifically, by passing acidic electrolyzed water through the weakly acidic cation exchange resin 233, cations (hardness components) adsorbed on the weakly acidic cation exchange resin 233 undergo an ion exchange reaction with hydrogen ions contained in the acidic electrolyzed water, thereby regenerating the weakly acidic cation exchange resin 233.

[0874] The acidic electrolyzed water flowing through the first soft water tank 203 contains cations and flows into the first recovery flow path 237 . That is, the acidic electrolyzed water containing cations flowing through the weakly acidic cation exchange resin 233 is recovered to the electrolytic tank 209 via the first recovery flow path 237 .

[0875] In this way, the soft water tank regeneration circulation flow path 239 is constructed as follows: the acidic electrolyzed water flows from the soft water tank located at the far downstream of the raw water inlet, that is, the soft water tank having a weakly acidic cation exchange resin 233 that adsorbs less hardness components than the soft water tank on the upstream side, that is, the downstream side of the second soft water tank 205, and flows into the downstream side of the first soft water tank 203 located upstream and having a weakly acidic cation exchange resin 233 that adsorbs more hardness components than the second soft water tank 205.

[0876] That is, the soft water tank regeneration circulation flow path 239 is a flow path that allows the acidic electrolyzed water sent out from the electrolytic tank 209 to circulate in the second soft water tank 205, and then to be sent to the first soft water tank 203 through the neutralization tank bypass flow path 242, so that it circulates in the first soft water tank 203 and flows into the electrolytic tank 209 through the first recovery flow path 237.

[0877] Thus, during the regeneration process, the acidic electrolyzed water discharged from the electrolytic tank 209 flows into the second soft water tank 205 having a smaller adsorption amount of hardness components than the first soft water tank 203 , and the acidic electrolyzed water containing hardness components is discharged from the second soft water tank 205 to the first soft water tank 203 .

[0878] In the regeneration of the weakly acidic cation exchange resin 233 in the second soft water tank 205 , the consumption of hydrogen ions in the acidic electrolyzed water is less than that in the first soft water tank 203 , so the decrease in hydrogen ion concentration can be suppressed compared to the regeneration of the first soft water tank 203 .

[0879] Therefore, acidic electrolyzed water containing a large amount of hydrogen ions flows into the first soft water tank 203, thereby suppressing the re-adsorption of hardness components in the first soft water tank 203. Therefore, a decrease in regeneration efficiency can be suppressed, and regeneration time can be shortened.

[0880] On the other hand, alkaline electrolyzed water generated near the cathode of the electrolytic cell 209 flows through the second supply flow path 236 and the capture unit 210, is sent to the second neutralization tank 206 through the flow path switching valve 227, and flows through the weakly basic anion exchange resin 234 inside.

[0881] The alkaline electrolyzed water flowing through the second neutralization tank 206 then flows through the soft water tank bypass flow path 244 , is sent into the first neutralization tank 204 via the flow path switching valve 225 , and flows through the weakly basic anion exchange resin 234 therein.

[0882] Specifically, by passing alkaline electrolyzed water through the weakly basic anion exchange resin 234, anions adsorbed on the weakly basic anion exchange resin 234 undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water, thereby regenerating the weakly basic anion exchange resin 234.

[0883] The alkaline electrolyzed water containing anions flowing through the first neutralization tank 204 then flows into the second recovery channel 238 . That is, the alkaline electrolyzed water containing anions flowing through the weakly basic anion exchange resin 234 is recovered to the electrolytic tank 209 via the second recovery channel 238 .

[0884] In this way, the neutralization tank regeneration circulation flow path 240 is constructed as follows: the alkaline electrolyzed water flows from the neutralization tank located at the farthest downstream of the raw water inlet, that is, the downstream side of the second neutralization tank 206 having a weakly basic anion exchange resin 234 that adsorbs less anions than the neutralization tank on the upstream side, and flows into the downstream side of the first neutralization tank 204 located upstream and having a weakly basic anion exchange resin 234 that adsorbs more anions than the second neutralization tank 206.

[0885] That is, the neutralization tank regeneration circulation flow path 240 is a flow path that allows the alkaline electrolyzed water sent out from the electrolytic tank 209 to circulate in the second neutralization tank 206, and then be sent to the first neutralization tank 204 through the soft water tank bypass flow path 244, so that it circulates in the first neutralization tank 204 and flows into the electrolytic tank 209 through the second recovery flow path 238.

[0886] Thus, during the regeneration process, alkaline electrolyzed water flows into the second neutralization tank 206 , which has a smaller anion adsorption amount than the first neutralization tank 204 , and the alkaline electrolyzed water containing anions is discharged from the second neutralization tank 206 to the first neutralization tank 204 .

[0887] In the regeneration of the weakly basic anion exchange resin 234 in the second neutralization tank 206 , the consumption of hydroxide ions in the alkaline electrolyzed water is less than that in the first neutralization tank 204 , so the decrease in hydroxide ion concentration can be suppressed compared to the regeneration of the first neutralization tank 204 .

[0888] Therefore, alkaline electrolyzed water containing a large amount of hydroxide ions flows into the first neutralization tank 204, which can suppress the re-adsorption of anions in the first neutralization tank 204. Therefore, a decrease in the regeneration treatment efficiency can be suppressed, and the regeneration time can be shortened.

[0889] In addition, in the neutralization tank regeneration circulation flow path 240, the alkaline electrolyzed water sent out from the electrolytic tank 209 is introduced into the first neutralization tank 204 and the second neutralization tank 206 from their respective downstream sides, and is made to flow out from the upstream side of each neutralization tank where the adsorption amount of anions is greater than that of the downstream side.

[0890] As a result, alkaline electrolyzed water flows from the downstream side, where the amount of adsorbed anion components is smaller, to regenerate the neutralization tank. During the regeneration of the weakly basic anion exchange resin 234 on the downstream side, the consumption of hydroxide ions in the alkaline electrolyzed water is less than that on the upstream side, thereby suppressing the decrease in the hydroxide ion concentration of the alkaline electrolyzed water.

[0891] This prevents anions contained in the alkaline electrolyzed water from the downstream side from being reabsorbed upstream. This prevents a decrease in the regeneration efficiency of the neutralization tank, shortening the regeneration time. It should be noted that the downstream side (or upstream side) in the neutralization tank and softening tank refers to the downstream side (or upstream side) of the flow path during the softening treatment.

[0892] Then, in the water softening device 201 , when the time period identified by the control unit 215 is reached or when the regeneration process exceeds a certain time (eg, 3 hours), the regeneration process is terminated and the electrolytic cell cleaning process described later is performed.

[0893] It should be noted that if the user wants to obtain soft water during the regeneration process, by opening a faucet connected to the softening device 201, raw water flows from the inlet 202 through the flow path 253 and out of the water intake 207. Therefore, raw water can be used even without waiting for the regeneration process to end.

[0894] (15.3 Electrolytic Cell Cleaning Process)

[0895] Next, refer to Figure 21 and Figure 23 The operations of the water softening device 201 during the electrolytic cell cleaning process will be described in the columns “during regeneration” and “during electrolytic cell cleaning”.

[0896] In the regeneration process, if the electrolytic cell 209 is operating, hardness components (calcium ions and magnesium ions) in water are deposited on the cathode in the form of solid (scale).

[0897] The precipitate deposited on the cathode is a non-conductor, which increases the operating voltage of the electrolytic cell 209 and the power consumption during the regeneration process. Therefore, it is necessary to perform an electrolytic cell cleaning process to remove the precipitate deposited on the cathode.

[0898] In the third embodiment, by the condition A (refer to Figure 23 ) is operated to remove scale attached to the second main electrode 259, which serves as the cathode, during positive electrolysis. The electrolytic cell cleaning process under condition A will be described below.

[0899] During the electrolytic cell cleaning process, on-off valves 218 to 222 are opened, and on-off valve 223 is closed. Furthermore, flow path switching valve 224 is connected so that water can be supplied from flow path 228 to flow path 229, flow path switching valve 225 is connected so that water can be supplied to soft water tank bypass flow path 244, flow path switching valve 226 is connected so that water can be supplied to first supply flow path 235, and flow path switching valve 227 is connected so that water can be supplied to second supply flow path 236.

[0900] That is, the first soft water tank 203 and the electrolytic tank 209 are in communication with each other, the electrolytic tank 209 and the drain port 213 are in communication with each other, and the electrolytic tank 209 and the capture unit drain port 214 are in communication with each other.

[0901] Therefore, if Figure 21 As shown, a first drain flow path 246 and a third drain flow path 250 are formed.

[0902] In the electrolytic cell cleaning step, specifically, by opening the on-off valve 219 , raw water flows from the outside into the first drain flow path 246 and the third drain flow path 250 .

[0903] The raw water flowing into the first drainage flow path 246 flows through the flow path 228 , the first recovery flow path 237 , and the first water supply pump 211 , and flows into the electrolytic cell 209 .

[0904] On the other hand, the raw water flowing into the third drainage flow path 250 flows through the flow path 228 , the first soft water tank 203 , the second recovery flow path 238 , and the second water supply pump 212 , and flows into the electrolytic cell 209 .

[0905] Under condition A of the electrolytic cell cleaning of the third embodiment, the application of voltage to the first main electrode 258 and the second main electrode 259 is stopped, and voltage is applied to the first auxiliary electrode 260 and the second auxiliary electrode 261 in such a manner that the first auxiliary electrode 260 functions as a cathode and the second auxiliary electrode 261 functions as an anode.

[0906] In this main electrode cleaning mode, alkaline electrolyzed water is generated near the first auxiliary electrode 260, filling the first chamber 256 with the alkaline electrolyzed water. Furthermore, acidic electrolyzed water is generated near the second auxiliary electrode 261, filling the second chamber 257 with the acidic electrolyzed water. Specifically, the acidic electrolyzed water generated at the second auxiliary electrode 261 dissolves and removes scale deposited on the second main electrode 259 during the regeneration process. This prevents degradation of electrolytic performance caused by deposits adhering to the surface of the second auxiliary electrode 261.

[0907] The alkaline electrolyzed water generated at the first sub-electrode 260 flows through the first supply flow path 235 , flows into the drain flow path 254 , and is discharged to the outside of the device through the drain port 213 .

[0908] Meanwhile, the acidic electrolyzed water generated by the second secondary electrode 261 dissolves scale deposited on the second main electrode 259, flows through the second supply flow path 236, and flows into the capture section 210. The acidic electrolyzed water flowing into the capture section 210 dissolves the deposits fixed to the capture section 210, thereby preliminarily cleaning the capture section 210. This shortens the time required for the subsequent capture section cleaning process. The acidic electrolyzed water is then discharged from the device through the capture section drain port 214 located at the bottom of the capture section 210.

[0909] That is, in the electrolytic cell cleaning step, the removal of precipitates in the electrolytic cell 209 and the removal of precipitates in the capturing portion 210 can be performed simultaneously, and the time required from the completion of the regeneration step to the start of the water softening step can be shortened.

[0910] Furthermore, in the water softening device 201 of the third embodiment, when the time period identified by the control unit 215 has arrived, or when the electrolytic cell cleaning process exceeds a certain time (e.g., 5 minutes), the electrolytic cell cleaning process is terminated, and the regeneration process (electrolyzed water generation mode) and the electrolytic cell cleaning process (condition A) are alternately repeated until the regeneration process completion time identified by the control unit 215 (e.g., 8 hours) is reached. Specifically, by alternately executing the electrolyzed water generation mode and the main electrode cleaning mode, a voltage increase caused by scale deposited on the second main electrode 259 can be prevented.

[0911] As a result, in the first main electrode 258 and the second main electrode 259 , there is no need to perform reverse electrolysis processing for exchanging the roles of the anode and the cathode, and thus electrode degradation due to reverse electrolysis can be suppressed.

[0912] Furthermore, the execution time in the main electrode cleaning mode is set to be shorter than that in the electrolyzed water generation mode during the regeneration process (e.g., electrolyzed water generation mode: 3 hours, main electrode cleaning mode: 10 minutes). Since the electrolysis time of the first and second auxiliary electrodes 260, 261 is short, the progression of electrode degradation of the first and second auxiliary electrodes 260, 261 can be significantly suppressed. During a single regeneration cycle, the amount of precipitate deposited on the first auxiliary electrode 260, which functions as the cathode, is minimal, and the frequency of reverse electrolysis between the first and second auxiliary electrodes 260, 261 is also low, thus suppressing electrode degradation.

[0913] Note that in third drain flow path 250, raw water passes through first soft water tank 203, becoming acidic, and then passes through capture section 210. Consequently, capture section 210 becomes acidic, and the precipitates fixed to capture section 210 are dissolved by the acidic water. This allows for preliminary cleaning of capture section 210, shortening the time required for the subsequent capture section cleaning step.

[0914] That is, the removal of precipitates in the electrolytic cell 209 and the removal of precipitates in the capture unit 210 can be performed simultaneously, thereby shortening the time required from the end of the regeneration process to the start of the water softening process. In addition, after the electrolytic cell cleaning process under condition A is performed, the process proceeds to the regeneration flow path cleaning process.

[0915] It should be noted that when the user wants to obtain soft water during the electrolytic cell cleaning process, by opening a faucet connected to the softening device 201, raw water flows from the inlet 202 through the flow path 253 and out of the water intake 207. Therefore, the raw water can be used even without waiting for the completion of the electrolytic cell cleaning process.

[0916] (15.4 Regeneration Flow Path Cleaning Procedure)

[0917] Next, refer to Figure 20 and Figure 23 In the column “Regeneration Flow Path Cleaning”, the operation of the water softening device 201 during the regeneration flow path cleaning process will be described in sequence.

[0918] In the water softening device 201 , hardness components are released from the first and second soft water tanks 203 and 205 into the acidic electrolyzed water during the regeneration process, and the acidic electrolyzed water circulates in the flow path without being discharged from the soft water tank regeneration circulation flow path 239 .

[0919] Therefore, after the regeneration process is complete, the soft water tank regeneration circulation flow path 239 is filled with high-hardness water containing hardness components released from the first soft water tank 203 and the second soft water tank 205. The hardness of this high-hardness water is significantly higher than that of the raw water (e.g., 450 ppm), sometimes reaching approximately 2000 ppm. While this high-hardness water remains in the softening device 201, when the process shifts to the softening process, the high-hardness water, or a mixture of raw water and high-hardness water, is discharged from the water intake 207.

[0920] Therefore, when the user of the water softening device 201 executes the water softening process after the regeneration process is completed, a problem occurs in that not only does soft water not get obtained immediately after the start of the water softening process, but water with a hardness higher than that of raw water gets obtained.

[0921] In addition, high-hardness water circulates in the weakly acidic cation exchange resin 233 in the first soft water tank 203 and the second soft water tank 205. Although the hardness components adsorbed in the regeneration process are replaced with hydrogen ions and regenerated, water containing hardness components will circulate again. Therefore, the hydrogen ions filled through the regeneration process with great difficulty exchange reaction with the hardness components, so that the hardness components are adsorbed on the weakly acidic cation exchange resin 233 again.

[0922] Therefore, the hydrogen ions available for softening the raw water decrease, and the softening performance is degraded. To solve these problems, a regeneration flow path cleaning process is performed to drain the high-hardness water in the soft water tank regeneration circulation flow path 239.

[0923] During the regeneration flow path cleaning process, on-off valves 221 to 223 are closed, and on-off valves 218 to 220 are opened. Furthermore, flow path switching valve 224 is connected so that water can be supplied from flow path 228 to neutralization tank bypass flow path 242. Flow path switching valve 225 is connected so that water can be supplied to soft water tank bypass flow path 244. Flow path switching valve 226 is connected so that water can be supplied from neutralization tank bypass flow path 242 to first supply flow path 235. Flow path switching valve 227 is connected so that water can be supplied to second supply flow path 236.

[0924] That is, the first soft water tank 203 and the second soft water tank 205 are in communication with each other, the second soft water tank 205 and the drain port 213 are in communication with each other, the electrolytic tank 209 and the drain port 213 are in communication with each other, and drainage from the capture unit drain port 214 is stopped.

[0925] Therefore, if Figure 20 As shown, a first drain flow path 246 and a second drain flow path 247 are formed.

[0926] Note that, at this time, the operations of the first main electrode 258 , the second main electrode 259 , the first sub-electrode 260 , the second sub-electrode 261 , the first water pump 211 , and the second water pump 212 are stopped.

[0927] In the regeneration flow path cleaning step, specifically, by opening the on-off valve 219 , raw water flows from the outside into the first drain flow path 246 and the second drain flow path 247 .

[0928] In first drain flow path 246, the pressure of the incoming raw water flushes the high-hardness water in flow path 228, first recovery flow path 237, first water supply pump 211, electrolytic cell 209, and first supply flow path 235, and flows into drain flow path 254. The high-hardness water flowing into drain flow path 254 is discharged outside the device through drain port 213.

[0929] In second drain flow path 247, the pressure of the incoming raw water is used to flush the high-hardness water in flow path 228, first soft water tank 203, neutralization tank bypass flow path 242, second soft water tank 205, and first supply flow path 235, and flow into drain flow path 254. The high-hardness water that has flowed into drain flow path 254 is discharged outside the device through drain port 213.

[0930] In this way, the regeneration flow path cleaning process can suppress the flow of high-hardness water in the first drainage flow path 246 and the second drainage flow path 247, which are the main remaining areas of high-hardness water after the regeneration process, to the neutralization tank and replace them with raw water.

[0931] Therefore, during the regeneration flow path cleaning process, the adsorption of hydrogen ions to the weakly basic anion exchange resin 234 in the neutralization tank can be suppressed, thereby suppressing the consumption of the filled hydroxide ions and maintaining the neutralization performance. Therefore, the reduction in water softening performance caused by high hardness water can be suppressed.

[0932] Note that the control unit 215 supplies raw water to each flow path so that the flow rate of raw water flowing through the second drain flow path 247 is greater than the flow rate of raw water flowing through the first drain flow path 246 .

[0933] This allows the high-hardness water in the second drain flow path 247, which includes the softening tank used during the water softening process and is necessary for draining the high-hardness water within the flow path, to be preferentially replaced with raw water. This prevents degradation of the water softening performance caused by high-hardness water at the start of the water softening process.

[0934] In addition, the first drainage flow path 246 is a flow path that is not used during the water softening process. It is a flow path that has little impact on the water softening process even if high-hardness water remains. Since the amount of drainage from the first drainage flow path 246 can be reduced, useless drainage can be prevented and the amount of water required for the regeneration flow path cleaning process can be suppressed.

[0935] Furthermore, this allows high-hardness water to be discharged from the device through a flow path that does not include a neutralization tank. Specifically, this prevents the hardness components in the high-hardness water stored in the soft water tank regeneration circulation flow path 239 from being adsorbed by the weakly basic anion exchange resin 234 in the neutralization tank, thereby draining the water. This prevents a decrease in softening performance due to high-hardness water generated during the regeneration process, maintaining softening performance.

[0936] Then, in the softening device 201, when it becomes a time period identified by the control unit 215, when the regeneration flow path cleaning process exceeds a certain time (for example, 1 minute), or when the water flow rate in the regeneration flow path cleaning process exceeds a certain value, the regeneration flow path cleaning process is terminated and the capture unit cleaning process is executed.

[0937] It should be noted that when the user wants to obtain soft water during the regeneration flow path cleaning process, by opening the faucet connected to the softening device 201, etc., the raw water flows from the inlet 202 through the flow path 253 and out of the water intake 207. Therefore, the raw water can be used even without waiting for the end of the regeneration flow path cleaning process.

[0938] (15.5 Capture Unit Cleaning Process)

[0939] Next, refer to Figure 22 and Figure 23 In the column “Cleaning the Capture Unit”, the operation of the water softening device 201 during the cleaning process of the capture unit will be described in sequence.

[0940] In the regeneration step, high-hardness water containing hardness components released from the first soft water tank 203 and the second soft water tank 205 flows into the electrolytic tank 209 .

[0941] The hardness component migrates to the cathode during electrolysis and reacts with hydroxide ions generated at the cathode to form precipitates. Part of the precipitates is contained in the alkaline electrolyzed water released from the electrolytic cell 209 , flows through the second supply flow path 236 , and is captured by the capture unit 210 .

[0942] As precipitates gradually accumulate in the capture section 210 during the regeneration process, the pressure loss caused by the capture section 210 gradually increases, and the flow rate of alkaline electrolyzed water flowing through the neutralization tank regeneration circulation flow path 240 gradually decreases. Therefore, if the precipitates are left standing, the time required to regenerate the weakly basic anion exchange resin 234 in the first neutralization tank 204 and the second neutralization tank 206 is prolonged, and ultimately, there is a possibility that the weakly basic anion exchange resin 234 may not be completely filled with hydroxide ions. Therefore, a capture section cleaning process is required to remove precipitates fixed to or deposited in the capture section 210.

[0943] During the capture unit cleaning process, on-off valves 218, 219, 222, and 223 are opened, and on-off valves 220 and 221 are closed. Furthermore, flow path switching valve 224 is connected so that water can be supplied from flow path 228 to flow path 229, flow path switching valve 225 is connected so that water can be supplied from flow path 229 to flow path 230, flow path switching valve 226 is connected so that water can be supplied from flow path 230 to flow path 231, and flow path switching valve 227 is connected so that water can be supplied from flow path 231 to second supply flow path 236.

[0944] That is, the first soft water tank 203 is connected to the first neutralization tank 204, the first neutralization tank 204 is connected to the second soft water tank 205, the second soft water tank 205 is connected to the second neutralization tank 206, and the second neutralization tank 206 is connected to the capture part drain outlet 214.

[0945] Therefore, if Figure 22 As shown, a fourth drainage flow path 252 (capturing portion cleaning flow path 251 ) is formed.

[0946] In the capture unit cleaning step, specifically, by opening the on-off valve 219 , raw water flows from the outside into the flow path 228 .

[0947] The inflowing raw water flows through the flow path 228 , the first soft water tank 203 , the flow path 229 , the first neutralization tank 204 , the flow path 230 , the second soft wa...

Claims

1. A water softening device that performs a softening step for softening raw water and a regeneration step for regenerating an ion exchange resin deteriorated by the softening step, the water softening device comprising: a softening tank which softens the raw water containing hardness components using a weakly acidic cation exchange resin to produce soft water in the softening step; A neutralization tank, which neutralizes the acidic soft water passing through the soft water tank using a weakly basic anion exchange resin in the soft water softening step, an electrolytic cell that generates electrolyzed water used in the regeneration step, an adsorption amount identification unit for identifying the ion adsorption amount of the specific ion species in the soft water tank based on the ion concentration of the specific ion species in the raw water, i.e., the raw water ion concentration, and the amount of the raw water introduced into the soft water tank; and a control unit configured to control execution of the regeneration step based on the ion adsorption amount identified by the adsorption amount identification unit, The control unit is configured to execute a replacement process when the operation time of the regeneration process reaches a reference operation time. The replacement process stops the operation of the electrolytic cell, drains the acidic electrolyzed water in the soft water tank, and introduces the raw water into the soft water tank.

2. The water softening device according to claim 1, wherein: The control unit is configured to determine the reference operation time based on the amount of ion adsorption and a current value of the electrolytic cell.

3. The water softening device according to claim 1, wherein: The control unit includes a number determination unit that determines the number of times the replacement process is performed in the regeneration process based on an ion concentration reference value (i.e., an ion concentration of the specific ion species capable of suppressing deterioration of the electrolytic cell), the raw water ion concentration, the ion adsorption amount, the reference operation time, and a regeneration operation time (i.e., a time from the start to the end of the regeneration process). The control unit is configured to execute the replacement step based on the number of executions determined by the number determination unit so that the average value of the ion concentration of the specific ion species in the electrolyzed water is equal to or less than the ion concentration reference value.

4. The water softening device according to claim 3, wherein: The control unit is configured to, when the replacing process is performed a plurality of times within the reference operating time, perform the replacing process a plurality of times based on the number of times the replacing process is performed and the reference operating time so that the time from the replacing process to the next replacing process is equal.

5. The water softening device according to claim 1, wherein: The specific ionic species is chloride ion.

6. The water softening device according to claim 1, wherein: The neutralization tank has at least two types of anion exchange resins as the anion exchange resins, which are separated from each other. The at least two types of anion exchange resins include a first anion exchange resin that is a weakly basic anion exchange resin and a second anion exchange resin that has a larger acid dissociation constant than the first anion exchange resin.

7. The water softening device according to claim 6, further comprising: an electrolytic cell that generates alkaline electrolyzed water for regenerating the anion exchange resin in the regeneration step, and A neutralization tank circulation flow path is independent of the soft water tank and connects the neutralization tank with the electrolytic tank to circulate the alkaline electrolyzed water generated in the electrolytic tank. The control unit has the following modes as the operation modes in the regeneration process: Regeneration mode, discharging the alkaline electrolyzed water introduced into the neutralization tank out of the device, and In the regeneration mode, the alkaline electrolyzed water introduced into the neutralization tank is circulated in the circulation flow path of the neutralization tank. The control unit is configured to execute the regeneration mode at the start of the regeneration process, and to execute the circulation regeneration mode after a predetermined time has elapsed since the execution of the regeneration mode.

8. The water softening device according to claim 7, further comprising a soft water tank circulation flow path, the soft water tank circulation flow path being independent of the neutralization tank and connecting the soft water tank with the electrolytic tank, so as to circulate the acidic electrolyzed water generated in the electrolytic tank. The control unit is configured to stop supplying the acidic electrolyzed water to the soft water tank circulation flow path in the regeneration mode and to circulate the acidic electrolyzed water in the soft water tank circulation flow path in the circulation regeneration mode.

9. The water softening device according to claim 6, wherein: The first anion exchange resin is a weakly basic anion exchange resin, and the second anion exchange resin is a strongly basic anion exchange resin.

10. The water softening device according to claim 6, wherein: The first anion exchange resin is a weakly basic anion exchange resin, and the second anion exchange resin is a weakly basic anion exchange resin having an acid dissociation constant greater than that of the weakly basic anion exchange resin used as the first anion exchange resin.

11. The water softening device according to claim 1, wherein: The electrolytic cell comprises: Room 1; a second chamber separated from the first chamber by a diaphragm; a first main electrode disposed in the first chamber and a first sub-electrode disposed upstream of the first main electrode; and a second main electrode disposed in the second chamber and a second sub-electrode disposed upstream of the second main electrode; The control unit is configured to execute: an electrolytic water generation mode, wherein the first main electrode is used as an anode and the second main electrode is used as a cathode to generate the electrolytic water; as well as The main electrode cleaning mode stops applying voltage to the first main electrode and the second main electrode, and performs electrolysis with the first sub-electrode serving as a cathode and the second sub-electrode serving as an anode, thereby cleaning the second main electrode.

12. The water softening device according to claim 11, wherein: The control unit is configured to alternately execute the electrolyzed water generation mode and the main electrode cleaning mode.

13. The water softening device according to claim 11, wherein: The execution time of the main electrode cleaning mode is shorter than the execution time of the electrolyzed water generating mode.

14. The water softening device according to claim 11, further comprising a first pump for conveying the electrolyzed water in the first chamber. The control unit is composed of: The auxiliary electrode cleaning mode is executed in a state where the water supply by the first pump and the application of voltage to the first auxiliary electrode and the second auxiliary electrode are stopped. The auxiliary electrode cleaning mode cleans the first auxiliary electrode by performing electrolysis using the first main electrode as an anode and the second main electrode as a cathode. The sub-electrode cleaning mode is performed after the main electrode cleaning mode.

15. The water softening device according to claim 11, wherein: The control unit is configured to execute a reverse main electrode cleaning mode in which the second main electrode is cleaned by performing electrolysis using the first main electrode as a cathode and the second main electrode as an anode. The inversion main electrode cleaning mode is performed after the main electrode cleaning mode.

16. The water softening device according to claim 11, wherein: The control unit is configured to execute a reverse auxiliary electrode cleaning mode, wherein the reverse auxiliary electrode cleaning mode stops applying voltage to the first main electrode and the second main electrode, performs electrolysis with the first auxiliary electrode as an anode and the second auxiliary electrode as a cathode, thereby cleaning the first auxiliary electrode. The inversion sub-electrode cleaning mode is performed after the main electrode cleaning mode.

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