Softening water device

Abstract

To provide a water softening apparatus capable of suppressing a decline in water softening performance caused by hardness components released from a water softening tank during a regeneration process of the water softening tank.SOLUTION: A water softening system 1 has a water softening tank 3, a neutralization tank 4, an electrolysis tank 12, a water storage tank 15, and a separation part 14. The water softening tank 3 softens raw water containing hardness components by means of a weakly acidic cation exchange resin 10. The neutralization tank 4 neutralizes pH of the softened water which has passed through the water softening tank by means of a weakly basic anion exchange resin 11. The electrolysis tank 12 produces acidic electrolytic water to regenerate the softening tank 3 and alkaline electrolytic water to regenerate the neutralization tank 4. The water storage tank 15 mixes the acidic electrolytic water which has circulated through the water softening tank 3 and the alkaline electrolytic water which has circulated through the neutralization tank 4 and supplies the same to the electrolysis tank 12. The separation part 14 is provided in a flow path connecting the electrolysis tank 12 and the neutralization tank 4, and separates precipitates caused by hardness components contained in the water introduced into the electrolysis tank 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water softening device for obtaining water for daily life. [Background technology]

[0002] In a conventional water softener using a weakly acidic cation exchange resin, a method of regenerating the cation exchange resin using acidic electrolyzed water produced by electrolysis is known as a method of regenerating the cation exchange resin without using salt (see, for example, Patent Document 1). The weakly acidic cation exchange resin has a proton at the end of the functional group, and softens the raw water by exchanging hardness components (e.g., calcium ions, magnesium ions) in the raw water with hydrogen ions. The hydrogen ions in the water softened by the weakly acidic cation exchange resin are neutralized by being adsorbed by a weakly basic anion exchange resin provided after the weakly acidic cation exchange resin. In a conventional water softener, a method of regenerating the weakly basic anion exchange resin using alkaline electrolyzed water produced by electrolysis is known as a method of regenerating the weakly basic anion exchange resin (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-30973 A [Patent Document 2] JP 2010-142674 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such conventional water softening devices, during regeneration treatment, hardness components (e.g., calcium ions, magnesium ions) released from the water softening tank may react with the alkaline electrolyzed water in the electrolytic tank, causing precipitates. If such precipitates flow into the neutralization tank and accumulate in the neutralization tank, restarting the water softening treatment may result in a decrease in water softening performance.

[0005] The present invention is devised to solve the above-mentioned problems of the conventional art, and aims to provide a water softening device that can suppress the deterioration of water softening performance caused by hardness components released from the water softening tank during the regeneration process of the water softening tank. [Means for solving the problem]

[0006] In order to achieve this object, the water softening device according to the present invention includes a water softening tank, a neutralization tank, an electrolytic tank, a water storage tank, and a separation unit. The water softening tank softens raw water containing hardness components with a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water passed through the water softening tank with a weakly basic anion exchange resin. The electrolytic tank generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening tank, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization tank. The water storage tank mixes the acidic electrolyzed water that has flowed through the water softening tank and the alkaline electrolyzed water that has flowed through the neutralization tank, and supplies the mixed water to the electrolytic tank. The separation unit is provided in a flow path that communicates between the electrolytic tank and the neutralization tank, and separates precipitates resulting from hardness components contained in the water introduced into the electrolytic tank. This achieves the intended object. Effect of the Invention

[0007] According to the present invention, it is possible to provide a water softening device capable of suppressing a decrease in water softening performance caused by hardness components released from the water softening tank during regeneration treatment of the water softening tank. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a water softening device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a configuration diagram showing a circulation flow path of the water softening device. [Diagram 3] FIG. 3 is a configuration diagram showing a cleaning flow path of the water softening device. [Figure 4] FIG. 4 is a diagram showing a state of the water softening device during operation. [Diagram 5] FIG. 5 is a conceptual diagram showing the configuration of a water softening device according to the second embodiment of the present invention. [Figure 6] FIG. 6 is a conceptual diagram showing the configuration of a water softening device according to the third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The water softening device according to the present invention includes a water softening tank, a neutralization tank, an electrolytic tank, a water storage tank, and a separation unit. The water softening tank softens raw water containing hardness components and chloride ions with a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water passed through the water softening tank with a weakly basic anion exchange resin. The electrolytic tank generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening tank, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization tank. The water storage tank mixes the acidic electrolyzed water that has flowed through the water softening tank and the alkaline electrolyzed water that has flowed through the neutralization tank, and supplies the resulting mixture to the electrolytic tank. The separation unit is provided in a flow path that communicates between the electrolytic tank and the neutralization tank, and separates precipitates resulting from hardness components contained in the water introduced into the electrolytic tank.

[0010] According to this configuration, when performing regeneration treatment of the water softening tank and the neutralization tank, the separation section can separate precipitates (precipitates caused by hardness components contained in the water introduced into the electrolytic tank) contained in the alkaline electrolytic water that has passed through the electrolytic tank, and the inflow of precipitates into the neutralization tank can be reduced. Therefore, when resuming the water softening treatment after the regeneration treatment is completed, the occurrence of the phenomenon observed in conventional water softening devices in which precipitates that have flowed into the neutralization tank react with hydrogen ions released from the water softening tank to become hardness components can be suppressed, and the deterioration of water softening performance due to dissolution of precipitates can be reduced.

[0011] The water softening device according to the present invention may further include a control unit for controlling the regeneration process of the weakly acidic cation exchange resin in the water softening tank and the weakly basic anion exchange resin in the neutralization tank, and the control unit may be configured to control the polarity inversion of the electrolytic tank after the end of the regeneration process, and to cause the acidic electrolyzed water after the polarity inversion to flow through the separation unit and to discharge it outside the device. With this configuration, the separation unit is cleaned (the precipitate separated in the separation unit is dissolved and removed), so that the frequency of maintenance of the separation unit can be reduced, and the water softening device can be used for a long period of time.

[0012] In addition, in the water softener according to the present invention, the control unit may be configured to control the end of polarity reversal of the electrolytic cell when the ion concentration determined based on the information on the ion concentration of the acidic electrolyzed water after polarity reversal after flowing through the separation unit becomes less than a reference value. With this configuration, the end of polarity reversal can be controlled based on the ion concentration contained in the acidic electrolyzed water after polarity reversal. Therefore, it is possible to flow the acidic electrolyzed water through the separation unit until the hardness components contained in the acidic electrolyzed water after flowing through the separation unit become less than the reference value, and the separation unit can be cleaned (separated precipitates are dissolved) more reliably. Therefore, the frequency of maintenance of the separation unit can be further reduced, and the water softener can be used for a long period of time.

[0013] In addition, in the water softening device according to the present invention, the water tank may further include a water tank separation section for separating precipitates resulting from hardness components contained in the water introduced into the tank. With this configuration, the precipitates can be separated not only by the separation section provided between the electrolytic tank and the neutralization tank, but also by the water tank separation section, so that the precipitates can be separated more reliably. Therefore, when the water softening process is resumed after the regeneration process is completed, the occurrence of the phenomenon seen in conventional water softening devices in which the precipitates that flow into the neutralization tank react with the hydrogen ions from the water softening tank to become hardness components can be suppressed, and the deterioration of water softening performance due to the dissolution of the precipitates can be further reduced.

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention. Also, each figure described in the embodiment is a schematic diagram, and the size and thickness ratios of each component in each figure do not necessarily reflect the actual dimensional ratios.

[0015] (Embodiment 1) A water softening device 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a conceptual diagram showing the configuration of the water softening device 1 according to the first embodiment of the present invention. Note that Fig. 1 conceptually shows each element of the water softening device 1.

[0016] (Overall composition) The water softening device 1 is a device that converts city water (raw water containing hardness components) supplied from the outside into neutral soft water that can be used as water for daily life.

[0017] Specifically, as shown in Fig. 1, the water softening device 1 includes an inlet 2 for raw water from the outside, a water softening tank 3, a neutralization tank 4, an intake port 5 for treated soft water, and a regeneration device 6. The regeneration device 6 includes an electrolytic tank 12, a separation section 14, a water storage tank 15, and a water pump 20. The water softening device 1 also includes a first drain outlet 16, a second drain outlet 18, a plurality of selection valves (selection valves 17, 19), a plurality of on-off valves (on-off valves 27 to 34), and a control section 35.

[0018] The inlet 2 is connected to city water. The water softening device 1 is capable of taking out softened water from the water intake 5 using the pressure of the city water.

[0019] The inlet 2 is connected to the water intake 5 by flow paths 7, 8, and 9. Flow path 7 connects the inlet 2 to the water softening tank 3. Flow path 8 connects the water softening tank 3 to the neutralization tank 4. Flow path 9 connects the neutralization tank 4 to the water intake 5.

[0020] In other words, flow path 7 is a flow path that guides raw water containing hardness components from inlet 2 to water softening tank 3. Furthermore, flow path 8 is a flow path that guides raw water softened in water softening tank 3 to neutralization tank 4. Flow path 9 is a flow path that guides softened water neutralized in neutralization tank 4 to water intake 5.

[0021] In other words, in the water softening process in the water softening device 1, city water supplied from outside flows through the inlet 2, flow path 7, water softening tank 3, flow path 8, neutralization tank 4, flow path 9, and water intake 5 in that order, and is discharged as neutral soft water.

[0022] (Water softening tank and neutralization tank) The water softening tank 3 is filled with a weakly acidic cation exchange resin 10, and the neutralization tank 4 is filled with a weakly basic anion exchange resin 11.

[0023] Here, the weak acid cation exchange resin 10 is not particularly limited and can be any general-purpose one. For example, it can be one that uses a carboxyl group (-COOH) as an exchange group. In addition, it can be one that uses a hydrogen ion ( H + ) is a metal ion, an ammonium ion ( NH 4 + ) may be used as a cation.

[0024] The weakly basic anion exchange resin 11 is not particularly limited, and any general-purpose resin may be used, for example, a free base type resin.

[0025] The water softening tank 3 softens raw water containing hardness components by the action of the weakly acidic cation exchange resin 10. More specifically, the water softening tank 3 is equipped with the weakly acidic cation exchange resin 10 having hydrogen ions at the ends of the functional groups. The water softening tank 3 exchanges cations (calcium ions, magnesium ions) that are hardness components contained in the flowing water (raw water) with hydrogen ions, thereby reducing the hardness of the raw water and softening the raw water. In addition, since the ends of the functional groups of the weakly acidic cation exchange resin 10 are hydrogen ions, the weakly acidic cation exchange resin 10 can be regenerated using acidic electrolyzed water in the regeneration process described below. At this time, the weakly acidic cation exchange resin 10 releases cations that are hardness components that were taken in during the water softening process.

[0026] Raw water containing hardness components is passed through the water softening tank 3 from a flow path 7, and by passing through the weakly acidic cation exchange resin 10 filled inside, the raw water containing hardness components is softened and passed through a flow path 8 to the neutralization tank 4. However, the softened water treated with the weakly acidic cation exchange resin 10 contains a large amount of hydrogen ions that have been exchanged for hardness components.

[0027] The neutralization tank 4 neutralizes the pH of the soft water (acidified soft water) containing hydrogen ions coming out of the water softening tank 3 by the action of the weakly basic anion exchange resin 11, converting it into neutral water (neutral soft water). More specifically, the neutralization tank 4 is provided with the weakly basic anion exchange resin 11, which adsorbs the hydrogen ions contained in the soft water from the water softening tank 3 together with anions (negative ions), thereby increasing the pH of the soft water and making it neutral soft water. The weakly basic anion exchange resin 11 can be regenerated using alkaline electrolyzed water in the regeneration process described below.

[0028] Soft water containing hydrogen ions is passed through the neutralization tank 4 from a flow path 8, and as it passes through a weakly basic anion exchange resin 11 filled inside, the acidified soft water coming out of the water softening tank 3 is neutralized, and the neutral soft water is passed to the outside through a flow path 9.

[0029] (playback device) The regeneration device 6 is a device that regenerates the weakly acidic cation exchange resin 10 in the water softening tank 3 and regenerates the weakly basic anion exchange resin 11 in the neutralization tank 4. Specifically, the regeneration device 6 includes the electrolytic tank 12, the separation section 14, the water storage tank 15, and the water pump 20, as described above. In the regeneration device 6, a first supply flow path 22, a first recovery flow path 23, a second supply flow path 24, and a second recovery flow path 25 are connected to the flow paths 7, 8, and 9 from the inlet 2 to the water intake 5, respectively. Each of the flow paths constitutes a circulation flow path 21 (first circulation flow path 21a, second circulation flow path 21b) described later.

[0030] Here, the first supply flow path 22 is a flow path that supplies acidic electrolyzed water from the electrolytic cell 12 to the water softening cell 3. The first supply flow path 22 is composed of a first supply flow path 22a that connects the electrolytic cell 12 and the selection valve 17, and a first supply flow path 22b that connects the selection valve 17 and the water softening cell 3. The first recovery flow path 23 is a flow path that recovers water containing hardness components that has passed through the water softening cell 3 to the water storage tank 15. The second supply flow path 24 is a flow path that supplies alkaline electrolyzed water from the electrolytic cell 12 to the neutralization cell 4. The second supply flow path 24 is composed of a second supply flow path 24a that connects the electrolytic cell 12 and the selection valve 19, and a second supply flow path 24b that connects the selection valve 19 and the water softening cell 3. The second recovery flow path 25 is a flow path that recovers water that has passed through the neutralization cell 4 to the water storage tank 15.

[0031] (electrolytic cell) The electrolytic cell 12 generates and discharges acidic electrolyzed water and alkaline electrolyzed water by electrolyzing the input water (water supplied from the water tank 15) using a pair of electrodes 13 (electrodes 13a and 13b) provided therein. More specifically, the electrode 13a, which serves as an anode during electrolysis, generates hydrogen ions by electrolysis to generate acidic electrolyzed water. The electrode 13b, which serves as a cathode during electrolysis, generates hydroxide ions by electrolysis to generate alkaline electrolyzed water. The electrolytic cell 12 supplies the acidic electrolyzed water to the water softener tank 3 via the first supply flow path 22, and supplies the alkaline electrolyzed water to the neutralizer tank 4 via the second supply flow path 24. As will be described in detail later, the acidic electrolyzed water generated by the electrolytic cell 12 is used to regenerate the weakly acidic cation exchange resin 10 in the water softener tank 3, and the alkaline electrolyzed water generated by the electrolytic cell 12 is used to regenerate the weakly basic anion exchange resin 11 in the neutralizer tank 4. The electrolytic cell 12 is configured so that the state of current flow to the pair of electrodes 13 can be controlled by a control unit 35 described later.

[0032] The electrolytic cell 12 also performs polarity inversion when cleaning the separation unit 14 (when cleaning the separation unit), which will be described later. Here, polarity inversion is performed by switching the anode and cathode of the pair of electrodes 13 and applying a voltage. That is, at the electrode 13a, which becomes the cathode during polarity inversion, hydroxide ions are generated by electrolysis to produce alkaline electrolyzed water. At the electrode 13b, which becomes the anode during polarity inversion, hydrogen ions are generated by electrolysis to produce acidic electrolyzed water. Thus, at polarity inversion, the electrolytic cell 12 supplies acidic electrolyzed water to the second supply flow path 24a and alkaline electrolyzed water to the first supply flow path 22a. As will be described later in detail, at polarity inversion, the alkaline electrolyzed water sent from the electrolytic cell 12 flows through the first supply flow path 22a, and is discharged from the first drain port 16 to the outside of the device via the selection valve 17 and the first drain flow path 37. On the other hand, the acidic electrolyzed water discharged from the electrolytic cell 12 flows through the second supply flow path 24a, flows into the separation section 14 provided on the second supply flow path 24a, and after cleaning the separation section 14, is discharged outside the device from the second drain outlet 18 via the selection valve 19 and the second drain flow path 38.

[0033] In the electrolytic cell 12, the polarity inversion is terminated after a certain time (for example, 5 minutes) has elapsed since the polarity inversion began.

[0034] (Water tank) The water tank 15 secures and stores the water to be circulated through the circulation flow path 21 (see FIG. 2) when regenerating the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11. The water tank 15 also mixes the acidic electrolyzed water containing hardness components that has been circulated through the water softening tank 3 with the alkaline electrolyzed water containing anions that has been circulated through the neutralization tank 4, and supplies the mixed water to the electrolysis tank 12.

[0035] The water that has flowed through the water tank 15 is passed through the electrolytic cell 12, where it is electrolyzed into acidic electrolyzed water and alkaline electrolyzed water, which are then supplied to the water softener cell 3 and neutralizer cell 4, respectively. The acidic electrolyzed water and alkaline electrolyzed water are reused in the water softener cell 3 and neutralizer cell 4, respectively, and then passed (recovered) back into the water tank 15. Therefore, the acidic electrolyzed water and alkaline electrolyzed water used for regenerating the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11 can be reused.

[0036] (Water pump) The water pump 20 is a device that circulates water through the circulation flow path 21 (see FIG. 2) during regeneration treatment by the regeneration device 6. The water pump 20 is provided in a water supply flow path 36 that communicates between the water tank 15 and the electrolytic cell 12. The water pump 20 is preferably disposed upstream of the electrolytic cell 12 and downstream of the water tank 15. The reason for such an arrangement is that the single water pump 20 can easily circulate water through the first circulation flow path 21a and the second circulation flow path 21b described below. The water pump 20 is also connected to a control unit 35 described below wirelessly or via wire to be able to communicate with each other.

[0037] (separation part) The separation unit 14 is provided in the second supply flow path 24a that communicates between the electrolytic cell 12 and the selection valve 19. The separation unit 14 separates precipitates contained in the alkaline electrolyzed water sent from the electrolytic cell 12. The precipitates are reaction products generated in the electrolytic cell 12 by the reaction of the alkaline electrolyzed water with the cation-based hardness components released from the softening cell during the regeneration process of the softening cell. More specifically, the electrolysis of water is performed in the electrolytic cell 12, and acidic electrolyzed water is obtained at the anode side (electrode 13a) and passed through the first supply flow path 22a. The alkaline electrolyzed water containing anions (e.g., hydroxide ions) is obtained at the cathode side (electrode 13b) and passed through the second supply flow path 24a. During the electrolysis in the electrolytic cell 12, the hardness components (e.g., calcium ions, magnesium ions) released from the softening cell 3 during the regeneration process move to the cathode side. Since alkaline electrolyzed water is generated on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates. For example, when the hardness components are calcium ions, a reaction occurs in which calcium carbonate is generated or a reaction occurs in which calcium hydroxide is generated when the hardness components are mixed with the alkaline electrolyzed water. The precipitates derived from the hardness components are separated as precipitates in the separation section 14 provided on the second supply flow path 24a. By separating the precipitates derived from the hardness components in the separation section 14, it is possible to prevent the precipitates from flowing into the neutralization tank 4 and accumulating. Therefore, when the water softening process is resumed after the regeneration process is completed, the precipitates accumulated in the neutralization tank 4 react with the hydrogen ions released from the water softening tank 3 to form hardness components, and it is possible to prevent an increase in the hardness of the soft water discharged from the neutralization tank 4. During the regeneration process, the alkaline electrolyzed water from which the precipitates derived from hardness components have been separated in the separation unit 14 flows through the neutralization tank 4 and is mixed with the acidic electrolyzed water, and then electrolyzed again in the electrolysis tank 12 to produce acidic electrolyzed water and alkaline electrolyzed water, which are respectively used to regenerate the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11. At this time, the acidic electrolyzed water contains less hardness components than city water or the water not provided with the separation unit 14.In other words, by separating the precipitate in the separation section 14, the hardness of the acidic electrolyzed water is reduced, so that the amount of hardness components flowing into the water softening tank 3 can be reduced, and the decrease in the regeneration efficiency of the weakly acidic cation exchange resin 10 can be suppressed.

[0038] The phrase "hardness components react" does not only mean that all of the hardness components react, but also includes a state in which non-reactive components or components that do not exceed the solubility product are present.

[0039] The separation unit 14 may have any form as long as it can separate the precipitates generated by the reaction between the hardness components and the alkaline electrolyzed water. For example, it may be a cartridge type filter, a filtration layer using a granular filter medium, a cyclone type solid-liquid separator, a hollow fiber membrane, or the like.

[0040] A cartridge-type filter can be mentioned as a means commonly used as the form of the separation unit 14. As the cartridge-type filter, a depth filtration type such as a thread-wound filter, a surface filtration type such as a pleated filter and a membrane filter, or a combination of these can be used.

[0041] The thread-wound filter is compatible with particle sizes of 1 to 150 micrometers and is mainly used as a prefilter. Pleated filters and membrane filters are available that are compatible with a wide range of particle sizes, from about 0.03 to 100 micrometers, but in particular, in the practice of the present invention, filters with an accuracy of about 0.5 to 1.5 micrometers are preferred for capturing hardness components that precipitate in the regeneration process described below. Since alkaline electrolyzed water flows through the separation section 14 in the regeneration process described below and acidic electrolyzed water flows through the separation section 14 in the cleaning process described below, the material of the cartridge-type filter is preferably a material that is highly resistant to corrosion by acids and alkalis (e.g., polypropylene).

[0042] The granular filter medium used in the filtration layer is intended to capture and remove hardness components, but depending on the presence of particles with a surface potential that can be adsorbed by the granular filter medium, ions in the raw water, etc., particles with a particle diameter of about 1 to 10 micrometers or chromaticity can also be removed. The granular filter medium can be a filter medium suitable for the object to be removed, such as filter sand or pellet-shaped fiber filter medium. The material of the granular filter medium may be, for example, sand, anthracite, garnet, ceramics, granular activated carbon, iron oxyhydroxide, manganese sand, etc., as long as it has a hardness that allows it to settle in water and is not easily deformed by pressure. The particle diameter may be, for example, 0.3 to 5.0 mm, and the uniformity coefficient may be 1.2 to 2.0.

[0043] In addition, the multi-layer filtration method uses a mixture of filter media with different specific gravities, stacking different sized particles from the bottom up, starting with the smallest particles, as layers for filtration. In multi-layer filtration, particles with high specific gravity and small size are generally mixed with particles with low specific gravity and large size to create a multi-layer structure. Compared to using a single type of filter media, the multi-layer filtration method is preferable because it has the advantages of high filtration efficiency per unit volume while keeping head loss low. For example, 0.3 mm garnet and 0.6 mm sand are used as granular filter media. M A mixture of 1.0 mm diameter granules and 1.0 mm diameter anthracite is used in a 2:1:1 ratio, but it is preferable to adjust the mixing ratio and particle size according to the particle characteristics of the suspended solids.

[0044] (Shut-off valve and selection valve) A plurality of on-off valves (on-off valves 27 to 34) are provided in each flow path, respectively, and switch between an "open" state and a "closed" state in each flow path. The selection valve 17 is provided in the first supply flow path 22, and determines the flow direction of electrolyzed water generated by electrolysis at the electrode 13a of the electrolytic bath 12. Specifically, the selection valve 17 switches between a flow state in which the electrolyzed water generated by electrolysis at the electrode 13a flows through the first supply flow path 22 (first supply flow path 22a and first supply flow path 22b) to the water softening bath 3, and a flow path state in which the electrolyzed water generated by electrolysis at the electrode 13a flows from the first supply flow path 22a to the first drain outlet 16 via the first drain flow path 37. The selection valve 19 is provided in the second supply flow path 24, and determines the flow direction of electrolyzed water generated by electrolysis at the electrode 13b of the electrolytic bath 12. Specifically, the selection valve 19 switches between a flow state in which the electrolyzed water generated by electrolysis at the electrode 13b flows through the separation unit 14 and the second supply flow path 24 (the second supply flow path 24a and the second supply flow path 24b) to reach the neutralization tank 4, and a flow path state in which the electrolyzed water generated by electrolysis at the electrode 13b flows from the second supply flow path 24a to the second drain port 18 via the separation unit 14 and the second drain flow path 38. In addition, the multiple on-off valves (on-off valves 27 to 34), the selection valve 17, and the selection valve 19 are each connected to a control unit 35 described later so as to be able to communicate wirelessly or by wire.

[0045] (Drain port) The first drain outlet 16 and the second drain outlet 18 discharge the electrolyzed water (acidic electrolyzed water and alkaline electrolyzed water) flowing out of the electrolytic cell 12 to the outside of the apparatus during cleaning of the separation section 14 (during separation section cleaning) and during drainage following the separation section cleaning, which will be described later.

[0046] During separation section cleaning, the first drain outlet 16 discharges alkaline electrolyzed water that flows out of the electrolytic cell 12 and flows through the first supply flow path 22a and the first drain flow path 37 to the outside of the device. During drainage, the first drain outlet 16 discharges water (such as alkaline electrolyzed water remaining in the flow paths) that flows out of the electrolytic cell 12 and flows through the first supply flow path 22a and the first drain flow path 37 to the outside of the device.

[0047] During cleaning of the separation section, the second drain outlet 18 discharges to the outside of the apparatus the acidic electrolyzed water that flows out of the electrolytic cell 12 and flows through the second supply flow path 24a, the separation section 14, and the second drain flow path 38. During drainage, the second drain outlet 18 discharges to the outside of the apparatus the water that is sent out of the electrolytic cell 12 and flows through the second supply flow path 24a, the separation section 14, and the second drain flow path 38 (water such as acidic electrolyzed water remaining in the flow paths).

[0048] (Control unit) The control unit 35 controls the softening process for softening raw water containing hardness components. The control unit 35 also controls the regeneration process for the weakly acidic cation exchange resin 10 in the softening tank 3 and the weakly basic anion exchange resin 11 in the neutralization tank 4. The control unit 35 also controls the polarity reversal of the electrolytic tank 12. The control unit 35 also controls the switching of the softening process, regeneration process, cleaning process, and wastewater process of the water softener 1. In this case, the control unit 35 controls the operation of the electrode 13, the water pump 20, the on-off valve 27, the on-off valve 28, the on-off valve 29, the on-off valve 30, the on-off valve 31, the on-off valve 32, the on-off valve 33, the on-off valve 34, the selection valve 17, and the selection valve 19, and executes the switching of the softening process, the regeneration process, the cleaning process, and the wastewater process, each process, and the polarity reversal.

[0049] (Flow path) Next, the circulation flow path 21 formed during the regeneration treatment of the water softening device 1 will be described with reference to Fig. 2. Fig. 2 is a configuration diagram showing the circulation flow path 21 of the water softening device 1.

[0050] Although the explanation will be repeated, as shown in Fig. 2, in the water softening device 1, the electrolytic cell 12 and the water tank 15 constituting the regeneration device 6 are connected in communication with each other via a water supply flow path 36. The electrolytic cell 12 and the water tank 15 are also connected in communication with the flow paths 7, 8 and 9 from the inlet 2 to the water intake 5 via a first supply flow path 22, a first recovery flow path 23, a second supply flow path 24 and a second recovery flow path 25, respectively. In the regeneration device 6, the circulation flow path 21 is formed by combining these flow paths.

[0051] The first supply flow path 22 is a flow path that supplies acidic electrolyzed water from the electrolytic cell 12 to the water softening cell 3, and is provided with a selection valve 17 and an on-off valve 27. The first supply flow path 22 is composed of a first supply flow path 22a that connects the electrolytic cell 12 and the selection valve 17, and a first supply flow path 22b that connects the selection valve 17 and the water softening cell 3. In other words, the water softening device 1 is provided with the first supply flow path 22 that allows acidic electrolyzed water to be drawn from the electrolytic cell 12 and sent to the upstream side of the water softening cell 3.

[0052] The first recovery flow path 23 is a flow path that recovers the water containing hardness components that has passed through the water softening tank 3 into the water tank 15, and an on-off valve 28 is provided in the flow path. That is, the water softening device 1 is provided with the first recovery flow path 23 that enables the upstream side of the water tank 15 to be connected to the downstream side of the water softening tank 3.

[0053] The second supply flow path 24 is a flow path that supplies alkaline electrolyzed water from the electrolytic cell 12 to the neutralization cell 4 via the separation unit 14, and is provided with a selection valve 19 and an on-off valve 29. The second supply flow path 24 is composed of a second supply flow path 24a that connects the electrolytic cell 12 and the selection valve 19, and a second supply flow path 24b that connects the selection valve 19 and the neutralization cell 4. That is, the water softener 1 is provided with the second supply flow path 24 that separates precipitates derived from hardness components contained in the alkaline electrolyzed water drawn from the electrolytic cell 12 in the separation unit 14, and allows the alkaline electrolyzed water from which the precipitates have been separated to be fed upstream of the neutralization cell 4.

[0054] The second recovery flow path 25 is a flow path that recovers the water that has passed through the neutralization tank 4 to the water tank 15, and an on-off valve 30 is provided in the flow path. That is, the water softening device 1 is provided with the second recovery flow path 25 that enables the upstream side of the water tank 15 to be connected to the downstream side of the neutralization tank 4.

[0055] The circulation flow path 21 includes a first circulation flow path 21a through which water pumped out of the water tank 15 by the water supply pump 20 circulates through the water softening tank 3, and a second circulation flow path 21b through which water pumped out of the water tank 15 by the water supply pump 20 circulates through the neutralization tank 4.

[0056] 2 (white arrow), the first circulation flow path 21a is a flow path through which water sent out from the water tank 15 by the water supply pump 20 circulates through the electrolytic cell 12 and the water softening tank 3, and returns to the water tank 15. More specifically, the first circulation flow path 21a is a flow path through which the water sent out from the water tank 15 by the water supply pump 20 circulates by flowing through the water supply flow path 36, the electrolytic cell 12, the first supply flow path 22a, the selection valve 17, the first supply flow path 22b, the on-off valve 27, the water softening tank 3, the first recovery flow path 23, the on-off valve 28, and the water tank 15 in this order.

[0057] 2 (black arrow), the second circulation flow path 21b is a flow path through which water sent out from the water tank 15 by the water supply pump 20 circulates through the electrolytic cell 12 and the neutralization cell 4, and returns to the water tank 15. More specifically, the second circulation flow path 21b is a flow path through which the water sent out from the water tank 15 by the water supply pump 20 circulates by flowing through the water supply flow path 36, the electrolytic cell 12, the second supply flow path 24a, the selection valve 19, the second supply flow path 24b, the on-off valve 29, the neutralization cell 4, the second recovery flow path 25, the on-off valve 30, and the water tank 15 in this order.

[0058] Here, in order to circulate water in the circulation flow path 21, an on-off valve 31 is provided downstream of the inlet 2 in the flow path 7. By closing the on-off valve 31 and opening the on-off valve 27, the first supply flow path 22 is connected in communication with the upstream side of the water softening tank 3. This makes it possible to supply acidic electrolyzed water from the electrolytic tank 12 to the water softening tank 3.

[0059] Further, an on-off valve 32 is provided in the flow path 8 downstream of the first recovery flow path 23 and upstream of the second supply flow path 24b. By closing the on-off valve 32 and opening the on-off valve 28, the first recovery flow path 23 is connected in communication with the downstream side of the water softening tank 3. This makes it possible for the water softening device 1 to recover, in the water storage tank 15, the water that has flowed through the water softening tank 3 (acidic electrolyzed water containing hardness components).

[0060] Furthermore, by closing the on-off valve 32 and opening the on-off valve 29, the second supply flow path 24 is connected to the upstream side of the neutralization tank 4. This allows the water softener 1 to supply alkaline electrolyzed water from the electrolytic tank 12 to the neutralization tank 4.

[0061] In addition, an on-off valve 33 is provided in the flow path 9 downstream of the neutralization tank 4. By closing the on-off valve 33 and opening the on-off valve 30, the second recovery flow path 25 is connected in communication with the downstream of the neutralization tank 4. This makes it possible to recover the water (alkaline electrolyzed water containing anions) that has passed through the second recovery flow path 25 into the water tank 15.

[0062] In addition, an on-off valve 34 is provided in the water supply flow path 36 downstream of the water tank 15 (at a position between the water tank 15 and the water supply pump 20). By closing the on-off valve 34, water can be stored in the water tank 15. On the other hand, by opening the on-off valve 34, water can be supplied to the water supply flow path 36.

[0063] Further, the first supply flow path 22 (first supply flow path 22a and first supply flow path 22b) is provided with a selection valve 17. By switching the selection valve 17, it is possible to set a flow state in which electrolyzed water generated by electrolysis at the electrode 13a flows through the first supply flow path 22a and the first supply flow path 22b to reach the water softening tank 3, and a flow path state in which the electrolyzed water generated by electrolysis at the electrode 13a is discharged from the first supply flow path 22a through a first drainage flow path 37 described later and to the outside of the device through a first drainage outlet 16.

[0064] Further, the second supply flow path 24 (the second supply flow path 24a and the second supply flow path 24b) is provided with a selection valve 19. By switching the selection valve 19, it is possible to set a flow state in which the electrolyzed water generated by electrolysis at the electrode 13b flows through the second supply flow path 24a and the second supply flow path 24b to reach the water softening tank 3, and a flow path state in which the electrolyzed water generated by electrolysis at the electrode 13b is discharged from the second supply flow path 24a through a first drainage flow path 37 described later and to the outside of the device through a second drainage outlet 18.

[0065] In addition, by closing the on-off valve 33, the circulation of water to the circulation flow path 21 can be started, while by opening the on-off valve 33, the circulation of water to the circulation flow path 21 can be stopped.

[0066] Next, the cleaning flow path 26 formed during the cleaning process of the water softening device 1 will be described with reference to Fig. 3. Fig. 3 is a configuration diagram showing the cleaning flow path 26 of the water softening device 1.

[0067] Although the explanation will be repeated, as shown in Fig. 3, the regeneration device 6 is composed of an electrolytic cell 12, a separation section 14, and a water tank 15. The water tank 15 is connected to the flow path 9 by a second recovery flow path 25. The electrolytic cell 12 and the water tank 15 are also connected to each other by a water supply flow path 36. The electrolytic cell 12 is connected to the first drain outlet 16 by a first supply flow path 22a and a first drainage flow path 37. The electrolytic cell 12 is also connected to the second drain outlet 18 by a second supply flow path 24a and a second drainage flow path 38. In the regeneration device 6, a cleaning flow path 26 is formed by combining each of the flow paths.

[0068] The first drainage flow path 37 is a flow path that drains water from the selection valve 17 to the first drain outlet 16. That is, the water softening device 1 is provided with the first drainage flow path 37 that draws water from the selection valve 17 to the first drain outlet 16 and enables the water to be discharged outside the device.

[0069] The second drainage flow path 38 is a flow path that drains water from the selection valve 19 to the second drain outlet 18. That is, the water softening device 1 is provided with the second drainage flow path 38 that draws water from the selection valve 19 to the second drain outlet 18 and enables the water to be discharged outside the device.

[0070] The cleaning flow path 26 includes a first cleaning flow path 26a and a second cleaning flow path 26b.

[0071] As shown in FIG. 3 (diagonal and horizontal arrows), the first cleaning flow path 26a is a flow path through which water introduced from the inlet 2 flows in the order of flow path 7, water softening tank 3, flow path 8, neutralization tank 4, second recovery flow path 25, water storage tank 15, water supply flow path 36, and electrolytic tank 12, and after being electrolyzed in the electrolytic tank 12, flows as alkaline electrolyzed water through the first supply flow path 22a, selection valve 17, and first drainage flow path 37, and is discharged outside the device from the first drainage outlet 16.

[0072] As shown in FIG. 3 (hatched arrow and meshed arrow), the second cleaning flow path 26b is a flow path through which water introduced from the inlet 2 flows in the order of flow path 7, water softening tank 3, flow path 8, neutralization tank 4, second recovery flow path 25, water storage tank 15, water supply flow path 36, and electrolytic tank 12, and after being electrolyzed in the electrolytic tank 12, flows as acidic electrolyzed water through the second supply flow path 24a (including the separation section 14), the selection valve 19, and the second drainage flow path 38, and is discharged outside the device from the second drainage outlet 18.

[0073] (Water softening, regeneration, cleaning, and wastewater treatment) Next, the water softening process, regeneration process, cleaning process, and drainage process of the water softening device 1 starting from the regeneration process will be described with reference to Fig. 4. Fig. 4 is a diagram showing the state of the water softening device 1 during operation.

[0074] In the water softening process, regeneration process, cleaning process, and drainage process, the control unit 35 controls the on-off valve 27, on-off valve 28, on-off valve 29, on-off valve 30, on-off valve 31, on-off valve 32, on-off valve 33, on-off valve 34, selection valve 17, selection valve 19, electrode 13 of electrolytic cell 12, and water pump 20 to switch to each flow state, as shown in Fig. 4. The control unit 35 has a computer system having a processor and a memory. The computer system functions as the control unit by the processor executing a program stored in the memory. The program executed by the processor is described here as being pre-recorded in the memory of the computer system, but may be recorded in a non-transitory recording medium such as a memory card and provided, or may be provided via an electric communication line such as the Internet.

[0075] Here, "ON" in FIG. 4 indicates that the corresponding on-off valve is "open", that the electrode 13 is energized, and that the water pump 20 is operating. A blank space indicates that the corresponding on-off valve is "closed", that the electrode 13 is not energized, and that the water pump 20 is stopped. The notation of the selection valve 17 and the selection valve 19 in FIG. 4 indicates that the flow path is open to the component (softening tank 3, neutralization tank 4, first drain port 16, or second drain port 18) corresponding to the number (symbol). The selection valve 17 in the normal state is in a state in which the flow path is open to the softening tank 3, but is left blank when it is not related to other processes. The selection valve 19 in the normal state is in a state in which the flow path is open to the neutralization tank 4, but is left blank when it is not related to other processes. The "ON (polarity change)" of the electrode 13 during the cleaning of the separation unit shown in FIG. 4 indicates that the electrode 13 is undergoing polarity change.

[0076] (Recycling) First, the operation of the regeneration device 6 of the water softening device 1 during regeneration treatment will be described in sequence with reference to the columns "Water injection" and "Regeneration" in FIG.

[0077] In the water softening apparatus 1, the water softening tank 3 filled with the weakly acidic cation exchange resin 10 loses or loses its cation exchange capacity with continued use. That is, after all of the hydrogen ions, which are the functional groups of the cation exchange resin, are exchanged with calcium ions or magnesium ions, which are hardness components, ion exchange becomes impossible. In this state, hardness components become contained in the treated water. For this reason, in the water softening apparatus 1, it becomes necessary to carry out a regeneration process of the water softening tank 3 and the neutralization tank 4 using the regeneration device 6.

[0078] Therefore, in the water softening device 1, once per predetermined period (for example, once per day (24 hours)), the control unit 35 identifies a time period during which the regeneration process is possible, and executes the regeneration process.

[0079] First, as shown in Fig. 4, when water is injected, the on-off valve 31 and the on-off valve 28 are opened. As a result, the water softening device 1 introduces raw water from the inlet 2 through the water softening tank 3 into the water tank 15 by the pressure of city water. At this time, the on-off valves 27, 32, 29, 33, 30, and 34 are closed. By storing a predetermined amount of water in the water tank 15 according to the capacity of the water softening device 1, the regeneration device 6 can ensure the amount of water during regeneration.

[0080] Next, during regeneration, on-off valves 31, 32, and 33 are closed, and on-off valves 27, 28, 29, 30, and 34 are opened, the water flow direction of selection valve 17 is set toward the water softening tank 3, and the water flow direction of selection valve 19 is set toward the neutralization tank 4, whereby a first circulation flow path 21a and a second circulation flow path 21b are formed, as shown in Figure 2.

[0081] When the electrodes 13 of the electrolytic cell 12 and the water pump 20 are operated, the water stored in the water tank 15 circulates through each of the first circulation flow path 21a and the second circulation flow path 21b.

[0082] At this time, the acidic electrolyzed water generated in the electrolytic cell 12 is fed into the water softening cell 3 through the first supply flow path 22 and flows through the weakly acidic cation exchange resin 10 therein. That is, by flowing the acidic electrolyzed water through the weakly acidic cation exchange resin 10, the cations (hardness components) adsorbed on the weakly acidic cation exchange resin 10 undergo an ion exchange reaction with the hydrogen ions contained in the acidic electrolyzed water. This regenerates the weakly acidic cation exchange resin 10. After that, the acidic electrolyzed water that has flowed through the weakly acidic cation exchange resin 10 contains cations and flows into the first recovery flow path 23. That is, the acidic electrolyzed water that has flowed through the weakly acidic cation exchange resin 10 and contains cations is collected in the water tank 15 through the first recovery flow path 23.

[0083] On the other hand, the alkaline electrolyzed water generated in the electrolytic bath 12 is fed into the neutralization bath 4 through the second supply flow path 24 and the separation unit 14 provided in the second supply flow path 24, and flows through the weakly basic anion exchange resin 11 inside. That is, by passing the alkaline electrolyzed water through the weakly basic anion exchange resin 11, anions adsorbed on the weakly basic anion exchange resin 11 undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water. This regenerates the weakly basic anion exchange resin 11. After that, the alkaline electrolyzed water that has passed through the weakly basic anion exchange resin 11 contains anions and flows into the second recovery flow path 25. That is, the alkaline electrolyzed water that has passed through the weakly basic anion exchange resin 11 and contains anions is recovered in the water tank 15 through the second recovery flow path 25.

[0084] In the water tank 15, the acidic electrolyzed water containing cations recovered from the water softening tank 3 and the alkaline electrolyzed water containing anions recovered from the neutralization tank 4 are mixed and neutralized.

[0085] At this time, by mixing acidic electrolyzed water containing cations (hardness components) with alkaline electrolyzed water containing anions, the hardness components react with hydroxide ions contained in the alkaline electrolyzed water to generate precipitates, but at least in the initial stage of the regeneration process, the amount of hydroxide ions contained in the alkaline electrolyzed water flowing from the neutralization tank 4 is small compared to the amount of hardness components released from the water softening tank 3, so that the precipitates are unlikely to be generated. Therefore, the hardness components contained in the neutralized electrolyzed water are sent to the electrolysis tank 12 as they are.

[0086] Thereafter, the electrolytic water mixed in the water tank 15 is passed again through the water supply passage 36 to the electrolytic cell 12. The passed water is then electrolyzed again in the electrolytic cell 12.

[0087] As described above, water is electrolyzed in the electrolytic cell 12, and a large amount of hydroxide ions are generated by electrolysis near the cathode, creating a state where precipitates are likely to occur. In other words, hardness components (e.g., calcium ions, magnesium ions) contained in the water supplied from the water tank 15 move to the cathode side and react with hydroxide ions to form precipitates. The alkaline electrolyzed water containing such precipitates is then sent to the second supply flow path 24a and flows into the separation unit 14.

[0088] In the separation section 14, precipitates contained in the alkaline electrolyzed water are separated, and alkaline electrolyzed water (treated water) from which hardness components have been removed can be obtained.

[0089] Here, the acidic electrolyzed water electrolyzed again in the electrolytic cell 12 and the alkaline electrolyzed water electrolyzed again in the electrolytic cell 12 and from which the precipitate has been separated by the separation part 14 are respectively used for regeneration of the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11.

[0090] Here, a problem that occurs in the neutralization tank of a conventional water softener is that during regeneration treatment, the hardness components released from the water softening tank react with the alkaline electrolyzed water in the electrolytic tank, producing precipitates that flow into the neutralization tank and accumulate in the neutralization tank. In other words, if the water softening treatment is resumed with the precipitates accumulated in the neutralization tank, they react with the hydrogen ions released from the water softening tank and become hardness components, resulting in a decrease in water softening performance. However, in this embodiment, the separation unit 14 separates the precipitates produced in the electrolytic tank 12, thereby making it possible to suppress the accumulation of precipitates caused by hardness components inside the neutralization tank 4.

[0091] Then, in the water softening device 1, when the regeneration process is completed, the polarity of the electrode 13 is inverted. Also, the on-off valves 27, 28, and 29 are closed, the on-off valves 31 and 32 are opened, the water flow direction of the selection valve 17 is switched from the direction toward the water softening tank 3 to the direction toward the first drain outlet 16, and the water flow direction of the selection valve 19 is switched from the direction toward the neutralization tank 4 to the direction toward the second drain outlet 18, thereby transitioning to the cleaning process.

[0092] (Cleaning process) In the water softening device 1, when the regeneration process is completed, the process proceeds to the cleaning process. Here, the cleaning process is a process for cleaning the separation section 14, in which the pair of electrodes 13 of the electrolytic cell 12 are reversed, and the acidic electrolyzed water generated in the electrolytic cell 12 at the time of the polarity reversal is caused to flow through the separation section 14, and the precipitates resulting from the hardness components separated in the separation section 14 are dissolved.

[0093] Next, the operation of the water softening device 1 during cleaning treatment will be described with reference to the section "During Cleaning" in FIG.

[0094] In the water softening device 1, as shown in Fig. 4, in the cleaning process (during cleaning), the on-off valve 30, the on-off valve 31, the on-off valve 32, and the on-off valve 34 are opened. As a result, the water softening device 1 introduces raw water from the inlet 2 through the water softening tank 3, the neutralization tank 4, the second recovery flow path 25, and the water storage tank 15 to the electrolytic tank 12 by the pressure of city water. At this time, the on-off valve 27, the on-off valve 28, the on-off valve 29, and the on-off valve 33 are closed. By circulating raw water through the water softening tank 3, the neutralization tank 4, and the second recovery flow path 25, the electrolytic water that has been circulating through the water softening tank 3, the neutralization tank 4, and the second recovery flow path 25 during the regeneration process can be replaced with raw water.

[0095] Next, the polarity of the electrode 13 is inverted, the water flow direction of the selection valve 17 is set to the first drain outlet 16 direction, and the water flow direction of the selection valve 19 is set to the second drain outlet 18 direction, forming the cleaning flow path 26 as shown in Fig. 3. By inverting the polarity, the electrolytic cell 12 is able to supply acidic electrolyzed water to the second supply flow path 24a and alkaline electrolyzed water to the first supply flow path 22a.

[0096] When the electrodes 13 of the electrolytic cell 12 and the water pump 20 are operated, raw water and electrolyzed water (acidic electrolyzed water, alkaline electrolyzed water) flow through the cleaning flow path .

[0097] At this time, the alkaline electrolyzed water produced in the electrolytic cell 12 flows through the first supply flow path 22a and the first drainage flow path 37, and is discharged from the first drainage outlet 16 to the outside of the device.

[0098] On the other hand, the acidic electrolyzed water generated in the electrolytic cell 12 is sent to the second drainage flow path 38 through the separation part 14 provided in the second supply flow path 24a, and is discharged to the outside of the device through the second drainage port 18. That is, by circulating the acidic electrolyzed water through the separation part 14, the precipitates caused by the hardness components captured in the separation part 14 react with the acidic electrolyzed water. As a result, the precipitates caused by the hardness components dissolve and become hardness components, which are included in the acidic electrolyzed water. After that, the acidic electrolyzed water that has circulated through the separation part 14 contains the hardness components, and is discharged to the outside of the device through the second drainage port 18. That is, by circulating the acidic electrolyzed water through the separation part 14 and discharging the circulated acidic electrolyzed water, the separation part 14 can be washed and the hardness components can be discharged to the outside of the device. This allows the separation part 14 to be washed, thereby reducing the decrease in the amount of water passing through due to clogging of the separation part 14. In addition, the number of maintenance operations for the separation part 14 can be reduced.

[0099] Then, in the water softening device 1, when the cleaning process is completed, polarity inversion of the electrodes 13 is terminated and operation is stopped. Also, the on-off valves 31 and 32 are closed to stop the inflow of city water, and the process shifts to wastewater treatment.

[0100] The cleaning process is terminated when a certain time (for example, 5 minutes) has elapsed from the start of polarity inversion.

[0101] (Wastewater treatment) In the water softening device 1, when the cleaning process is completed, the process proceeds to the drainage process. Here, the drainage process is a process for draining the raw water, the acidic electrolyzed water, and the alkaline electrolyzed water remaining in the cleaning flow path 26.

[0102] Next, the operation of the water softening device 1 during wastewater treatment will be described with reference to the section "During wastewater treatment" in FIG.

[0103] 4, in the water softening device 1, during wastewater treatment (during discharge), the on-off valves 27, 28, 29, 31, 32, and 33 are closed, and the on-off valve 30 is opened. This stops the inflow of city water from the inlet 2, and allows the raw water remaining in the path from inside the water softening tank 3 to the water tank 15 via the first recovery flow path 23 and the raw water remaining in the path from inside the neutralization tank 4 to the water tank 15 via the second recovery flow path 25 to flow into the water tank 15.

[0104] Next, the on-off valve 34 is opened, the water pump 20 is operating, and the electrode 13 is stopped operating. As a result, the raw water remaining in the path from the inside of the water tank 15 to the electrolytic cell 12 via the water supply flow path 36, the alkaline electrolyzed water remaining in the path from the inside of the electrolytic cell 12 to the first drain outlet 16 via the first supply flow path 22a and the first drain flow path 37, and the electrolyzed water remaining in the path from the inside of the electrolytic cell 12 to the second drain outlet 18 via the second supply flow path 24a and the second drain flow path 38 can be discharged to the outside of the device.

[0105] By performing the drainage treatment, it is possible to prevent the alkaline electrolyzed water remaining in the cleaning flow passage 26 from flowing into the softening tank 3 and the acidic electrolyzed water remaining in the cleaning flow passage 26 from flowing into the neutralization tank 4.

[0106] Then, in the water softening device 1, when the drainage treatment is completed, the operation of the water pump 20 is stopped. Also, the on-off valves 30 and 34 are closed, and the on-off valves 31, 32, and 33 are opened. Furthermore, the water flow direction of the selection valve 17 is set to the direction toward the water softening tank 3, and the water flow direction of the selection valve 19 is set to the direction toward the neutralization tank 4, thereby transitioning to the water softening treatment.

[0107] The end of the drainage process is determined to be a certain time (for example, one minute) after the start of the drainage process.

[0108] (Water softening treatment) When the wastewater treatment is completed, the water softening device 1 starts water softening treatment.

[0109] Next, the operation of the water softening device 1 during water softening treatment will be described with reference to the section "water softening" in FIG.

[0110] In the water softening apparatus 1, as shown in Fig. 4, in the water softening process (softening water), the on-off valve 33 provided at the water intake 5 is opened while the on-off valve 31 and the on-off valve 32 are open. In this way, the water softening apparatus 1 allows city water (raw water containing hardness components) from the outside to flow through the water softening tank 3 and the neutralization tank 4, and softened water (neutral soft water) can be taken out from the water intake 5. At this time, the on-off valves 27, 28, 29, 30, and 34 are all closed. The operation of the electrode 13 of the electrolytic tank 12 and the water pump 20 is also stopped.

[0111] Specifically, as shown in FIG. 1, in the water softening process, raw water is supplied from an inlet 2 through a flow path 7 to a water softening tank 3 by the pressure of city water. The raw water supplied to the water softening tank 3 flows through a weakly acidic cation exchange resin 10 provided in the water softening tank 3. At this time, cations, which are hardness components in the raw water, are adsorbed by the action of the weakly acidic cation exchange resin 10, and hydrogen ions are released (ion exchange is performed). The raw water is softened by removing the cations from the raw water. The softened water further passes through a flow path 8 and proceeds to a neutralization tank 4. In the neutralization tank 4, hydrogen ions contained in the softened water are adsorbed by the action of a weakly basic anion exchange resin 11. In other words, hydrogen ions are removed from the softened water after the treatment, so the lowered pH increases, and the water becomes softened neutral water for domestic use, which can be taken out from a water intake 5 through a flow path 9.

[0112] Then, in the water softening device 1, when a time period specified by the control unit 35 is reached or when the water softening process exceeds a certain period of time, the regeneration process is carried out.

[0113] In this manner, in the water softening device 1, the water softening process, the regeneration process, the cleaning process, and the drainage process are repeatedly performed.

[0114] As described above, according to the water softening device 1 according to the first embodiment, the following effects can be obtained.

[0115] (1) The water softening device 1 includes a water softening tank 3, a neutralization tank 4, an electrolytic tank 12, a water storage tank 15, and a separation unit 14. The water softening tank 3 softens raw water containing hardness components with a weakly acidic cation exchange resin 10. The neutralization tank 4 neutralizes the pH of the softened water that has passed through the water softening tank with a weakly basic anion exchange resin 11. The electrolytic tank 12 generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 10 in the water softening tank 3, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin 11 in the neutralization tank 4. The water storage tank 15 mixes the acidic electrolyzed water that has passed through the water softening tank 3 and the alkaline electrolyzed water that has passed through the neutralization tank 4, and supplies the resulting mixture to the electrolytic tank 12. The separation unit 14 is provided in a flow path that communicates between the electrolytic tank 12 and the neutralization tank 4, and separates precipitates resulting from hardness components contained in the water introduced into the electrolytic tank 12.

[0116] As a result, when performing regeneration treatment of the water softening tank 3 and the neutralization tank 4, the precipitates (precipitates caused by hardness components contained in the water introduced into the electrolytic tank 12) contained in the alkaline electrolyzed water that has passed through the electrolytic tank 12 can be separated in the separation section 14, and the inflow of the precipitates into the neutralization tank 4 can be reduced. Therefore, when the water softening treatment is resumed after the regeneration treatment is completed, the precipitates that have flowed into the neutralization tank 4 can be prevented from reacting with the hydrogen ions from the water softening tank 3 to become hardness components, and the decrease in water softening performance due to the dissolution of the precipitates can be reduced.

[0117] (2) The water softener 1 includes a control unit 35 that controls the regeneration process of the weakly acidic cation exchange resin 10 in the water softener tank 3 and the weakly basic anion exchange resin 11 in the neutralization tank 4. After the regeneration process is completed, the control unit 35 controls the polarity inversion of the electrolytic tank 12, and causes the acidic electrolyzed water after polarity inversion to flow through the separation unit 14 and be discharged outside the device. This allows the separation unit 14 to be cleaned (the precipitate separated in the separation unit 14 is dissolved and removed), thereby reducing the frequency of maintenance of the separation unit 14 and allowing the water softener 1 to be used for a long period of time.

[0118] (Embodiment 2) Next, a water softening device 1a according to a second embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a conceptual diagram showing the configuration of a water softening device 1a according to the second embodiment of the present invention.

[0119] The water softener 1a according to the second embodiment differs from the first embodiment in that an ion concentration detector 39 is provided downstream of the separation section 14. That is, in the water softener 1a according to the second embodiment, the polarity reversal of the electrolytic cell 12 is controlled to be terminated when the ion concentration becomes less than a reference value, based on information on the ion concentration of the acidic electrolyzed water after polarity reversal that has flowed through the separation section 14. The rest of the configuration of the water softener 1a is the same as that of the water softener 1 according to the first embodiment. Hereinafter, the contents already explained in the first embodiment will be omitted as appropriate, and the differences from the first embodiment will be mainly explained.

[0120] As shown in FIG. 5, the water softening device 1a includes an ion concentration detection unit 39 located downstream of the separation unit 14 and upstream of the selection valve 19 on the second supply flow path 24a.

[0121] During the cleaning process, the ion concentration detector 39 detects the ion concentration of the acidic electrolyzed water that has flowed through the separation unit 14. The ion concentration detector 39 is connected to the control unit 35 wirelessly or via wire so as to be able to communicate with the control unit 35, and information regarding the detected ion concentration is used as an input signal for the control unit 35.

[0122] Here, a general-purpose device can be used as the ion concentration detection unit 39, such as a detector that measures the electrical conductivity of a liquid or a detector that measures the amount of TDS (Total Dissolved Solids) contained in water.

[0123] Water (pure water) is an insulator that does not conduct electricity by itself, but it becomes conductive when various substances are dissolved (ionized). In other words, the electrical conductivity of a liquid is an index of the amount of ionized substances contained in the liquid. In general city water, it is proportional to the content of calcium ions, magnesium ions, sodium ions, chloride ions, etc., which are abundant in river water or groundwater that is the source of the city water. In this embodiment, TDS represents the total concentration of ions (calcium ions, magnesium ions, chloride ions, hydrogen ions, etc.) contained in the water flowing through the ion concentration detection unit 39 during the cleaning process. In water of the same water system, electrical conductivity and TDS are approximately proportional to each other.

[0124] The control unit 35 controls the electrolytic cell 12 to end polarity reversal when the ion concentration determined based on the information on the ion concentration output from the ion concentration detection unit 39 becomes less than the reference value. On the other hand, the control unit 35 controls the electrolytic cell 12 to continue polarity reversal when the ion concentration is equal to or greater than the reference value. This allows the control unit 35 to control the end of polarity reversal based on the ion concentration contained in the acidic electrolyzed water after polarity reversal. Therefore, it is possible to pass the acidic electrolyzed water through the separation unit 14 until the ion concentration contained in the acidic electrolyzed water after passing through the separation unit 14 becomes less than the reference value.

[0125] Here, the ion concentration determined based on the information on the ion concentration output from the ion concentration detection unit 39 is the difference between the ion concentration contained in the acidic electrolyzed water after it has flowed through the separation unit 14 when there is no deposit in the separation unit 14, and the ion concentration contained in the acidic electrolyzed water after it has flowed through the separation unit 14 during the cleaning process. The reference value is a value that specifies the difference in ion concentration to be within a predetermined range.

[0126] As described above, according to the water softening device 1a of the second embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be obtained.

[0127] (3) In the water softener 1a, the control unit 35 controls the electrode reversal of the electrolytic cell 12 to end when the ion concentration determined based on the information on the ion concentration (concentration of hardness components) of the acidic electrolyzed water after electrode reversal that has flowed through the separation unit 14 becomes less than the reference value. This allows the end of electrode reversal to be controlled based on the information on the ion concentration contained in the acidic electrolyzed water after electrode reversal. Therefore, it is possible to flow the acidic electrolyzed water through the separation unit 14 until the ion concentration determined based on the information on the ion concentration contained in the acidic electrolyzed water after electrode reversal becomes less than the reference value, and the separation unit 14 can be cleaned (separated precipitates can be dissolved) more reliably. This further reduces the maintenance frequency of the separation unit 14, resulting in a water softener 1a that can be used for a long period of time.

[0128] (Embodiment 3) Next, a water softening device 1b according to a third embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is a conceptual diagram showing the configuration of a water softening device 1b according to the third embodiment of the present invention.

[0129] The water softening device 1b according to the third embodiment differs from the first embodiment in that the water softening device 1b further includes a water tank separating section 40 in the water tank 15. Other than this, the configuration of the water softening device 1b is the same as that of the water softening device 1 according to the first embodiment. Below, the contents already explained in the first embodiment will not be explained again as appropriate, and the differences from the first embodiment will be mainly explained.

[0130] 6, the water softening device 1b includes a water tank separation section 40 near the outlet of the water tank 15 (the connection between the water tank 15 and the water supply flow path 36). That is, in the water softening device 1b, the separation section 14 and the water tank separation section 40 separate precipitates caused by hardness components.

[0131] As described above, in the water tank 15, the amount of hydroxide ions contained in the alkaline electrolyzed water is small in the early stage of the regeneration process, but since the regeneration of the neutralization tank 4 is completed earlier than the regeneration of the water softening tank 3, the amount of hydroxide ions contained in the alkaline electrolyzed water increases in the later stage of the regeneration process. That is, in the later stage of the regeneration process, the acidic electrolyzed water containing hardness components released from the water softening tank 3 and the alkaline electrolyzed water released from the neutralization tank 4 are mixed, and a precipitate is easily generated. As a result, the hardness components (e.g., calcium ions, magnesium ions) released from the water softening tank 3 react with the hydroxide ions from the neutralization tank 4 to become precipitates. Therefore, the water tank separation unit 40 separates the precipitates generated in the water tank 15. As with the separation unit 14, the water tank separation unit 40 may have any form as long as it can separate precipitates generated by the reaction between the hardness components and the alkaline electrolyzed water. As described above, examples of the configuration include a cartridge type filter, a filtration layer using a granular filter medium, a cyclone type solid-liquid separator, a hollow fiber membrane, and the like.

[0132] Then, the water tank 15 supplies the electrolytic water from which the precipitate has been separated by the water tank separation unit 40 to the electrolytic cell 12 via the water supply flow path 36. At this time, since the hardness components contained in the electrolytic water supplied to the electrolytic cell 12 have been reduced, the precipitates generated at the electrode 13b of the electrolytic cell 12 are also reduced.

[0133] As described above, according to the water softening device 1b of the third embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be obtained.

[0134] (4) In the water softening device 1b, the water tank 15 further includes a water tank separation section 40 that separates precipitates caused by hardness components contained in the water introduced into the tank. This allows the precipitates to be separated not only by the separation section 14 provided between the electrolytic tank 12 and the neutralization tank 4 but also by the water tank separation section 40, so that the precipitates can be separated more reliably. Therefore, when the water softening process is resumed after the regeneration process is completed, it is possible to prevent the precipitates that have flowed into the neutralization tank 4 from reacting with the hydrogen ions from the water softening tank 3 to become hardness components as in the conventional water softening device, and it is possible to further reduce the deterioration of the water softening performance caused by the dissolution of the precipitates.

[0135] (5) The water softener 1b is configured to have a separation section 14 provided downstream of the electrolytic cell 12 with respect to the cleaning flow path 26, and a water tank separation section 40 provided upstream of the electrolytic cell 12. This makes it possible to reduce the hardness components contained in the electrolytic water supplied to the electrolytic cell 12, thereby reducing the amount of precipitates produced in the electrolytic cell 12. This further reduces the frequency of maintenance of the separation section 14, making it possible to provide a water softener 1b that can be used for a long period of time.

[0136] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present invention.

[0137] In the water softener 1 according to the first embodiment, the regeneration process is executed when the time period specified by the control unit 35 is reached or the water softening process exceeds a certain time, but the present invention is not limited to this. For example, an ion concentration detection unit other than the ion concentration detection unit 39 may be provided downstream of the second recovery flow path 25 and upstream of the opening / closing valve 27, and the ion concentration detection unit may constantly detect the ion concentration (e.g., hardness component concentration) of the soft water flowing through the flow path 9, and the regeneration process may be executed not only when the time period specified by the control unit 35 is reached or the water softening process exceeds a certain time, but also when the ion concentration exceeds a preset reference value. This makes it possible to determine whether or not to execute the regeneration process based on the ion concentration of the water after it has flowed through the neutralization tank 4. Therefore, the state of the weakly acidic cation exchange resin 10 in the water softening tank 3 can be determined more accurately, and the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11 can be regenerated at an appropriate timing.

[0138] In the water softening device 1 according to the first embodiment, in the cleaning process (during cleaning), raw water is introduced from the inlet 2 through the water softening tank 3, the neutralization tank 4, the second recovery passage 25, and the water storage tank 15 into the electrolytic tank 12, but this is not limiting. For example, the first recovery passage 23 may be used instead of the second recovery passage 25. This allows the acidic electrolyzed water containing hardness components remaining in the first recovery passage 23 to be collected.

[0139] Furthermore, the water softening device 1 according to the first embodiment may be structured so as to further include an on-off valve and an air vent valve in the water tank 15. When the on-off valve provided in the water tank 15 is opened during drainage treatment, the water in the water tank 15 is drained to the outside by the action of the air vent valve. This makes it possible to shorten the time required for drainage treatment.

[0140] In the water softener 1 according to the first embodiment, the first drain outlet 16 and the second drain outlet 18 are provided as components for discharging the electrolyzed water sent from the electrolytic cell 12 to the outside of the device during cleaning and drainage treatment, but the present invention is not limited to this. For example, it is preferable to mix and discharge the alkaline electrolyzed water discharged from the first drain outlet 16 and the acidic electrolyzed water discharged from the second drain outlet 18. This allows the acidic electrolyzed water and the alkaline electrolyzed water to be neutralized and discharged.

[0141] In the water softening device 1 according to the first embodiment, the separation section 14 is configured to be cleaned, but the present invention is not limited to this. For example, the separation section 14 may not be cleaned. Although the above-mentioned effect (2) cannot be obtained, the effects of simplifying the device configuration, reducing the size of the device, and reducing the cost of the device can be enjoyed. [Industrial Applicability]

[0142] The water softening device according to the present invention can be applied to a point-of-use (POU) water purification device or a point-of-entry (POE) water purification device. [Explanation of symbols]

[0143] 1 Water softener 1a Water softener 1b Water softener 2 Inlet 3 Water softening tank 4 Neutralization tank 5. Water Intake 6 Playback device 7 Flow Path 8 Flow Path 9 Flow Path 10. Weakly acidic cation exchange resin 11 Weakly basic anion exchange resin 12 Electrolytic cell 13 electrodes 13a electrode 13b Electrode 14 Separation part 15 Water Tank 16 First drain 17 Selector valve 18 Second drain 19 Selector valve 20 Water Pump 21 Circulation flow path 21a First circulation channel 21b Second circulation flow path 22 First supply channel 22a First supply channel 22b First supply channel 23 First recovery channel 24 Second supply channel 24a Second supply channel 24b Second supply channel 25 Second recovery channel 26 Cleaning Channel 26a First cleaning channel 26b Second cleaning channel 27 On-off valve 28 On-off valve 29 On-off valve 30 On-off valve 31 On-off valve 32 On-off valve 33 On-off valve 34 On-off valve 35 Control section 36 Water supply channel 37 First drainage channel 38 Second drainage channel 39 Ion concentration detector 40 Water tank separation section

Claims

1. a water softening tank for softening raw water containing hardness components using a weakly acidic cation exchange resin; a neutralization tank for neutralizing the pH of the softened water that has passed through the softening tank with a weakly basic anion exchange resin; an electrolytic cell for producing acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening cell, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization cell; a water storage tank for mixing the acidic electrolyzed water that has passed through the softening tank and the alkaline electrolyzed water that has passed through the neutralization tank and supplying the resulting mixture to the electrolysis tank; a separation section provided in a flow path that communicates between the electrolytic cell and the neutralization cell, the separation section separating precipitates resulting from the hardness components contained in the water introduced into the electrolytic cell; A water softening device comprising:

2. A control unit for controlling the regeneration treatment of the weakly acidic cation exchange resin in the water softening tank and the weakly basic anion exchange resin in the neutralization tank is further provided.

2. The water softening apparatus according to claim 1, wherein the control unit controls the polarity inversion of the electrolytic cell after the completion of the regeneration process, and controls the acidic electrolyzed water after the polarity inversion to flow through the separation unit and to be discharged outside the apparatus.

3. The water softening apparatus according to claim 2, characterized in that the control unit controls to terminate polarity reversal of the electrolytic cell when an ion concentration determined based on information about the ion concentration of the acidic electrolyzed water after polarity reversal that has flowed through the separation unit becomes less than a reference value.

4. 4. The water softening device according to claim 1, wherein the water tank further comprises a water tank separation section that separates precipitates caused by the hardness components contained in the water introduced into the tank.

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