Water softening device

Abstract

The soft water device (1) of the present application is provided with a soft water tank (3), a neutralization tank (4), an electrolysis tank (12), a water feeding pump (19), a current value detecting unit (18), and a control unit (17) for controlling the regeneration process. The control unit (17) continues the regeneration process when the current value of the water feeding pump (19) detected by the current value detecting unit (18) is equal to or greater than a predetermined value, and stops the regeneration process and shifts to a hardness component discharge process for discharging the hardness component in the device to the outside of the device when the current value of the water feeding pump (19) detected by the current value detecting unit (18) is less than the predetermined value.

Description

Technical Field

[0001] This invention relates to a water softening apparatus for generating neutral soft water from raw water containing hardness components. Background Technology

[0002] In conventional water softening devices using weakly acidic cation exchange resins, a known method for regenerating the cation exchange resin without using salt is to regenerate it using acidic electrolyzed water generated by electrolysis (for example, see Patent Document 1). The weakly acidic cation exchange resin has protons at the ends of its functional groups and softens the raw water by exchanging hardness components (e.g., calcium ions, magnesium ions) for hydrogen ions. Furthermore, the raw water softened by the weakly acidic cation exchange resin contains hydrogen ions and becomes acidic. The hydrogen ions in this softened water are adsorbed by a weakly basic anion exchange resin located downstream of the weakly acidic cation exchange resin, thereby neutralizing the softened raw water. As a method for regenerating the weakly basic anion exchange resin, a known method is to regenerate it using alkaline electrolyzed water generated by electrolysis (for example, see Patent Document 2).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-30973

[0006] Patent Document 2: Japanese Patent Application Publication No. 2010-142674 Summary of the Invention

[0007] In this water softening device, as the regeneration of the weakly acidic cation exchange resin and the weakly basic anion exchange resin progresses, the hardness of both the acidic and alkaline electrolyzed water increases due to hardness components (such as calcium and magnesium ions) released from the weakly acidic cation exchange resin. The released hardness components react with the alkaline electrolyzed water to produce precipitates. When these precipitates flow into a neutralization tank and the water softening process restarts in a state of accumulation within the neutralization tank, a decrease in softening performance occurs. Therefore, as a countermeasure, the inventors discovered that providing a separation section to separate the precipitates is effective. However, precipitates gradually accumulate in the separation section during the regeneration process. Therefore, to prevent clogging of the separation section caused by precipitates, it is necessary to reduce the amount of hardness components in the device at an appropriate time.

[0008] The purpose of this invention is to provide a water softening device that can remove hardness components from the device at appropriate times and shorten the time required for regeneration.

[0009] The water softening apparatus of the present invention includes a softening tank, a neutralization tank, an electrolysis tank, a water pump, a current detection unit, and a control unit. The softening tank uses a weakly acidic cation exchange resin to soften raw water containing hardness components to generate soft water. The neutralization tank uses a weakly basic anion exchange resin to neutralize the pH of the soft water generated from the softening tank. The electrolysis tank generates acidic electrolyzed water, which regenerates the weakly acidic cation exchange resin in the softening tank, and alkaline electrolyzed water, which regenerates the weakly basic anion exchange resin in the neutralization tank. The water pump delivers the alkaline electrolyzed water to the neutralization tank. The current detection unit detects the current value of the water pump during operation. During regeneration, the control unit continues regeneration if the current value of the water pump detected by the current detection unit is above a predetermined value. Conversely, during regeneration, if the current value of the water pump detected by the current detection unit is below a predetermined value, the control unit stops the regeneration process and switches to a process to discharge the hardness components from the apparatus to the outside.

[0010] According to the present invention, a water softening device is provided that can remove hardness components from the device at appropriate times and shorten the time required for regeneration of the water softening device. Attached Figure Description

[0011] Figure 1 This is a conceptual diagram showing the structure of the water softening device according to Embodiment 1 of the present invention.

[0012] Figure 2 This is a structural diagram showing the circulation flow path of the water softening device according to Embodiment 1 of the present invention.

[0013] Figure 3 This is a structural diagram showing the cleaning flow path of the raw water separation section of the water softening device according to Embodiment 1 of the present invention.

[0014] Figure 4 This is a structural diagram showing the reclaimed water replacement flow path of the water softening device according to Embodiment 1 of the present invention.

[0015] Figure 5 This is a diagram showing the state of the water softening device according to Embodiment 1 of the present invention during operation.

[0016] Figure 6 This is a graph showing the performance curves of the water pump of the water softening device according to embodiments 1 to 3 of the present invention.

[0017] Figure 7 This is a conceptual diagram showing the structure of the water softening device according to Embodiment 2 of the present invention.

[0018] Figure 8 This is a structural diagram showing the cleaning flow path of the acid separation section of the water softening device according to Embodiment 2 of the present invention.

[0019] Figure 9 This is a structural diagram showing the reclaimed water replacement flow path of the water softening device according to Embodiment 2 of the present invention.

[0020] Figure 10 This is a diagram showing the state of the water softening device according to Embodiment 2 of the present invention during operation.

[0021] Figure 11 This is a conceptual diagram showing the structure of the water softening device according to Embodiment 3 of the present invention and the discharge flow path of the hardness component.

[0022] Figure 12 This is a diagram showing the state of the water softening device according to Embodiment 3 of the present invention during operation. Detailed Implementation

[0023] The water softening apparatus of the present invention includes a softening tank, a neutralization tank, an electrolysis tank, a water pump, a current detection unit, and a control unit. The softening tank uses a weakly acidic cation exchange resin to soften raw water containing hardness components to generate soft water. The neutralization tank uses a weakly basic anion exchange resin to neutralize the pH of the soft water generated from the softening tank. The electrolysis tank generates acidic electrolyzed water, which regenerates the weakly acidic cation exchange resin in the softening tank, and alkaline electrolyzed water, which regenerates the weakly basic anion exchange resin in the neutralization tank. The water pump delivers the alkaline electrolyzed water to the neutralization tank. The current detection unit detects the current value of the water pump during operation. During regeneration, the control unit continues regeneration if the current value of the water pump detected by the current detection unit is above a predetermined value. Conversely, during regeneration, if the current value of the water pump detected by the current detection unit is below a predetermined value, the control unit stops the regeneration process and switches to a process to discharge the hardness components from the apparatus to the outside.

[0024] Based on this structure, the operation status of the regeneration process can be monitored by detecting the flow rate of the water pump. Furthermore, when the current value of the water pump is lower than the specified value, the process switches to hardness component removal, thus allowing for timely switching to hardness component removal.

[0025] Alternatively, the water softening apparatus of the present invention may also include a separation unit. Alternatively, the separation unit may be provided in a flow path connecting the electrolytic cell and the neutralization cell, and may separate precipitates caused by hardness components contained in the alkaline electrolyzed water introduced into the electrolytic cell. Alternatively, the control unit may perform a raw water separation unit cleaning process relative to the separation unit, allowing raw water to flow in from the downstream side of the separation unit, to remove hardness components.

[0026] In this way, the separation section can be backwashed using raw water, and the precipitates containing hardness components that separate from the separation section can be discharged outside the device. Therefore, the pressure loss in the separation section can be reduced, and a sufficient amount of alkaline electrolyzed water can be supplied to the neutralization tank. Thus, it becomes a water softening device capable of regeneration without stagnation.

[0027] Alternatively, in the water softening apparatus of the present invention, the control unit may perform an acid separation section cleaning process, in which raw water is circulated into the water softening tank to generate acidic soft water, and the acidic soft water flows into the separation section from the downstream side of the separation section, as a process to discharge hardness components.

[0028] In this way, acidic soft water flowing in the softening tank can be used for backwashing of the separation section, thereby dissolving the precipitates containing hardness components that have formed in the separation section. Therefore, the efficiency of hardness component removal treatment can be improved, and the hardness component removal treatment can be completed in a shorter time.

[0029] Alternatively, in the water softening apparatus of the present invention, after the raw water separation unit has been cleaned, the control unit may be transferred to a regeneration water replacement process, in which the water in the circulation path (regeneration path) formed during the regeneration process is replaced with raw water. This allows the electrolyzed water, which contains a significant amount of hardness components released from the weakly acidic cation exchange resin, to be replaced with raw water. Consequently, the amount of hardness components in the regeneration path can be reduced, thus providing a water softening apparatus capable of regenerating the ion exchange resin without obstruction and shortening the regeneration time required for the water softening apparatus.

[0030] Alternatively, in the water softening apparatus of the present invention, the control unit may simultaneously perform the following actions: facilitating the flow of raw water into the water softening tank to generate acidic soft water and allowing the acidic soft water to flow in from the downstream side of the separation unit (acidic separation unit cleaning process); and replacing the water in the regeneration path with raw water (regeneration water replacement process), which contains a large amount of hardness components released from the weakly acidic cation exchange resin, as hardness components are discharged.

[0031] This improves the efficiency of regeneration and hardness component removal in water softening devices, allowing for faster transition to water softening.

[0032] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following embodiments are merely examples of embellishment of the present invention and do not limit the technical scope of the invention. Furthermore, the figures described in the embodiments are schematic diagrams, and the ratios of the size and thickness of each component in the figures may not reflect the actual size ratios.

[0033] (Implementation Method 1)

[0034] Reference Figure 1 The water softening apparatus 1 according to Embodiment 1 of the present invention will be described. Figure 1 This is a conceptual diagram showing the structure of the water softening device 1 according to Embodiment 1 of the present invention. It should be noted that... Figure 1 The various elements of the water softening device 1 are conceptually shown in the diagram.

[0035] (Overall structure)

[0036] The water softening device 1 is a device that generates neutral soft water from raw water containing hardness components supplied from the outside. It should be noted that the raw water refers to the water (the water to be treated) introduced into the device through inlet 2, such as municipal water or well water. The raw water contains hardness components (e.g., calcium or magnesium ions).

[0037] Specifically, such as Figure 1 As shown, the water softening device 1 includes an inlet 2, a water softening tank 3, a neutralization tank 4, a water intake 5, and a regeneration device 6. In addition, the water softening device 1 is composed of a drain outlet 16, a control unit 17, and multiple on / off valves (on / off valves 31 to 39 and on / off valves 42 to 45).

[0038] Inlet 2 is connected to the city water supply. Inlet 2 is the opening that directs city water into the water softening device 1.

[0039] Water inlet 5 is an opening that supplies water that has been softened and circulated within the water softening device 1 to the outside of the device. In the water softening device 1, softened water can be extracted from the water inlet 5 under the pressure of the raw water flowing in from the inlet 2.

[0040] The inlet 2 to the outlet 5 is connected by flow path 7, flow path 8 and flow path 9.

[0041] Flow path 7 is the flow path connecting the inlet 2 to the softening tank 3. That is, flow path 7 is the flow path that guides raw water containing hardness components from the inlet 2 to the softening tank 3.

[0042] Flow path 8 is the flow path connecting the softening tank 3 to the neutralization tank 4. That is, flow path 8 is the flow path that guides the acidic soft water softened by the softening tank 3 to the neutralization tank 4.

[0043] Flow path 9 is the flow path connecting the neutralization tank 4 to the water intake 5. That is, flow path 9 is the flow path that guides the soft water neutralized in the neutralization tank 4 to the water intake 5.

[0044] In summary, in the water softening device 1, during the water softening process, the urban water supplied from the outside flows in the order of inlet 2, flow path 7, water softening tank 3, flow path 8, neutralization tank 4, flow path 9 and water intake 5, and is discharged as neutral soft water.

[0045] (Water softening tank)

[0046] The softening tank 3 softens raw water containing hardness components under the action of a weakly acidic cation exchange resin 10. That is, it is also called the softening tank 3, which generates soft water by softening raw water containing hardness components. More specifically, the softening tank 3 is equipped with a weakly acidic cation exchange resin 10 having hydrogen ions at the terminal of its functional groups. The softening tank 3 exchanges cations (calcium ions, magnesium ions) containing hardness components in the flowing water (raw water) with hydrogen ions. Therefore, the hardness of the raw water introduced into the softening tank 3 decreases, and the raw water can be softened.

[0047] The water softening tank 3 is filled with a weakly acidic cation exchange resin 10. The weakly acidic cation exchange resin 10 is an ion exchange resin with hydrogen ions at the end of its functional groups. The weakly acidic cation exchange resin 10 adsorbs the cations (calcium ions, magnesium ions) that are hardness components contained in the raw water and releases hydrogen ions.

[0048] There are no particular limitations on the weakly acidic cation exchange resin 10; general-purpose materials can be used, such as materials that use carboxyl groups (-COOH) as exchange groups. Furthermore, the proton (H+) that acts as the counter ion to the carboxyl group can also be a metal ion, ammonium ion (NH4+), or other cations.

[0049] Furthermore, since the terminal functional groups of the weakly acidic cation exchange resin 10 are hydrogen ions, acidic electrolyzed water can be used to regenerate the weakly acidic cation exchange resin 10 during the regeneration process described later. During the regeneration process, cations that are hardness components introduced during the water softening process are released from the weakly acidic cation exchange resin 10.

[0050] (Neutralization tank)

[0051] Neutralization tank 4, under the action of weakly basic anion exchange resin 11, neutralizes the pH (hydrogen ion concentration index) of the soft water (acidified soft water) containing hydrogen ions discharged from softening tank 3, turning it into neutral water (neutral soft water). More specifically, neutralization tank 4 is equipped with weakly basic anion exchange resin 11, which adsorbs both hydrogen ions and anions contained in the soft water from softening tank 3. Therefore, under the action of neutralization tank 4, the pH of the soft water increases, and the acidified soft water becomes neutral soft water.

[0052] The neutralization tank 4 is filled with a weakly basic anion exchange resin 11. The weakly basic anion exchange resin 11 is an ion exchange resin having at least one amine selected from primary, secondary, and tertiary amines as functional groups. The weakly basic anion exchange resin 11 adsorbs hydrogen ions and anions released from the softening tank 3 together.

[0053] The weakly basic anion exchange resin 11 can be regenerated using alkaline electrolysis of water in the regeneration process described later. There are no particular limitations on the weakly basic anion exchange resin 11; general-purpose materials can be used, for example, materials that are free-base types.

[0054] (Regeneration device)

[0055] The regeneration device 6 is a device for regenerating 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. Specifically, the regeneration device 6 is configured including an electrolytic cell 12, a separation section 14, a water storage tank 15, and a water pump 19. Furthermore, the regeneration device 6 is connected to a first supply flow path 21, a first recovery flow path 22, a bypass flow path 29, a second supply flow path 23, and a second recovery flow path 24, respectively, along flow paths 7, 8, and 9 from the inlet 2 to the outlet 5. Details of each flow path will be described later.

[0056] (Electrolytic cell)

[0057] Electrolyzer 12 electrolyzes incoming water (water supplied from storage tank 15) using a pair of electrodes 13 (electrode 13a and electrode 13b) disposed inside, thereby generating and discharging acidic and alkaline electrolyzed water. More specifically, at electrode 13a, which acts as the anode during electrolysis, hydrogen ions are generated through electrolysis, producing acidic electrolyzed water. At electrode 13b, which acts as the cathode during electrolysis, hydroxide ions are generated through electrolysis, producing alkaline electrolyzed water. Electrolyzer 12 supplies acidic electrolyzed water to softening tank 3 via first supply path 21 and alkaline electrolyzed water to neutralization tank 4 via second supply path 23. The acidic electrolyzed water generated by electrolyzer 12 is used in the regeneration of the weakly acidic cation exchange resin 10 in softening tank 3, as detailed later. Similarly, the alkaline electrolyzed water generated by electrolyzer 12 is used in the regeneration of the weakly basic anion exchange resin 11 in neutralization tank 4. It should be noted that the electrolytic cell 12 is configured such that the energizing state of the pair of electrodes 13 can be controlled by the control unit 17 described later.

[0058] (Water storage tank)

[0059] The water storage tank 15 ensures and stores the regenerated weakly acidic cation exchange resin 10 and weakly basic anion exchange resin 11 in the circulation path 20 (see reference). Figure 2 The water flowing inside the cell. In addition, the water storage tank 15 mixes the acidic electrolyzed water containing hardness components that has flowed in the softening tank 3 with the alkaline electrolyzed water containing anions that has flowed in the neutralization tank 4, and supplies it to the electrolysis tank 12.

[0060] Furthermore, the water flowing in the storage tank 15 is introduced into the electrolysis tank 12, where it is electrolyzed to become acidic electrolyzed water and alkaline electrolyzed water, which are then supplied to the softening tank 3 and the neutralization tank 4, respectively. After being reused in the softening tank 3 and the neutralization tank 4, the acidic and alkaline electrolyzed water are then reintroduced into the storage tank 15 (recycled). Therefore, the acidic and alkaline electrolyzed water used in the regeneration of the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11 can be reused.

[0061] (Water pump)

[0062] Water pump 19 is used to circulate water through circulation path 20 (see reference 6) during the regeneration process performed by regeneration device 6. Figure 2 The device circulates water in the electrolytic cell 12. A water pump 19 is installed in the water delivery path 25 that connects the water storage tank 15 and the electrolytic cell 12. It should be noted that the water pump 19 is preferably located upstream of the electrolytic cell 12 and downstream of the water storage tank 15. This configuration is chosen because a single water pump 19 facilitates the circulation of water in both the first circulation path 20a and the second circulation path 20b. The water pump 19 is communicatively connected to the control unit 17 (described later) via wireless or wired connection. The current value of the water pump 19 is detected by the current value detection unit 18 within the control unit 17 (described later).

[0063] (Separation section)

[0064] The separation section 14 is provided in the second supply flow path 23 that connects the electrolytic cell 12 and the neutralization cell 4.

[0065] The separation section 14 separates the precipitates contained in the alkaline electrolyzed water supplied from the electrolyzer 12. The precipitates are reaction products generated within the electrolyzer 12 by the reaction of hardness components (e.g., cations released from the softening tank 3 during regeneration) with alkaline electrolyzed water. More specifically, during water electrolysis in the electrolyzer 12, hardness components (e.g., calcium ions, magnesium ions) released from the softening tank 3 during regeneration move towards the cathode (electrode 13b). Since alkaline electrolyzed water is generated at the cathode, the hardness components react with the alkaline electrolyzed water to become precipitates. For example, if the hardness component is calcium ions, mixing with alkaline electrolyzed water can cause a reaction that produces calcium carbonate or calcium hydroxide. The precipitates from the hardness components are separated as precipitates in the separation section 14 of the second supply flow path 23. Furthermore, the separation section 14 separates the precipitates from the hardness components, thereby preventing the precipitates from flowing into the neutralization tank 4 and accumulating. Therefore, when re-starting the softening process after the regeneration process, the reaction between the precipitates accumulated in the neutralization tank 4 and the hydrogen ions released from the softening tank 3 is prevented from forming hardness components, thus preventing an increase in the hardness of the softened water delivered from the neutralization tank 4. Additionally, during the regeneration process, the alkaline electrolyzed water, from which the precipitates from the hardness components have been separated by the separation section 14, flows through the neutralization tank 4. After mixing with acidic electrolyzed water, it is electrolyzed again in the electrolysis tank 12 and supplied as acidic and alkaline electrolyzed water, respectively, for the regeneration of 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 compared to municipal water or water without the separation section 14. That is, by using the separation section 14 to separate the precipitates, the hardness of the acidic electrolyzed water is reduced, thereby reducing the hardness component flowing into the softening tank 3 and suppressing the decrease in the regeneration efficiency of the weakly acidic cation exchange resin 10.

[0066] It should be noted that "hardness component reaction" refers not only to the complete reaction of hardness components, but also to the state of including unreacted components or components whose solubility product does not exceed a certain limit.

[0067] The separation unit 14 can separate the precipitates produced by the reaction of hardness components with alkaline electrolyzed water, regardless of the method used. For example, methods such as using a box-type filter, a filter layer using granular filter material, a cyclone solid-liquid separator, or a hollow fiber membrane can be used.

[0068] As a typical mechanism used as the separation unit 14, a cartridge-type filter can be cited. As a cartridge-type filter, a deep filtration type such as a wire-wound filter, a pleated filter, and a surface filtration type such as a membrane filter can be used, or a combination of these can be used.

[0069] Wire-wound filters correspond to particle sizes of 1 micrometer to 150 micrometers and are mainly used as pre-filters. Pleated filters and membrane filters have structures corresponding to a wider range of particle sizes, from 0.03 micrometers to 100 micrometers. It should be noted that, especially when implementing the present invention, it is preferable to use a structure with a precision of 0.5 micrometers to 1.5 micrometers for capturing hardness components precipitated during the regeneration process described later. In the separation section 14, alkaline electrolyzed water is supplied during the regeneration process described later, and acidic electrolyzed water is supplied during the cleaning process. Therefore, the material of the cartridge-type filter is preferably a raw material with high resistance to acid and alkali corrosion (e.g., polypropylene).

[0070] The granular filter media used in the filtration layer are intended to capture and remove hardness components. However, depending on the presence of particles with surface potential adsorbed onto the granular filter media, ions in the raw water, etc., particles with a diameter of approximately 1 to 10 micrometers or color can also be removed. Among granular filter media, filter sand is the most common, and granular fiber filter media and other filter media suitable for removing the target substances can also be used. The material of the granular filter media can be, for example, sand, anthracite, garnet, ceramic, granular activated carbon, ferric hydroxide, manganese sand, etc., which settle in water and have a hardness that is not easily deformed by pressure. For example, materials with a particle size of 0.3 mm to 5.0 mm and a uniformity coefficient of 1.2 to 2.0 are preferred.

[0071] Furthermore, multi-layer filtration, which uses a mixture of multiple types of filter media with different densities, involves stacking particles of different sizes sequentially from the smallest particles down as the filtration layers. In multi-layer filtration, denser, smaller particles are generally mixed with less dense, larger particles to create a multi-layer structure. Compared to methods using a single type of filter media, multi-layer filtration offers advantages such as higher filtration efficiency per unit volume and lower head loss, making it preferred. For example, a granular filter media can be used that is a 2:1:1 mixture of 0.3 mm garnet, 0.6 mm sand, and 1.0 mm anthracite; however, it is preferable to adjust the mixing ratio or particle size according to the particle characteristics of the turbid substances.

[0072] (On / off valves and selector valves)

[0073] Multiple on / off valves (on / off valves 31 to 39 and 42 to 45) are respectively installed at designated positions in multiple flow paths, and switch between an "open" state and a "closed" state in each flow path. In addition, the multiple on / off valves are communicatively connected to the control unit 17 described later, either wirelessly or via a wired connection.

[0074] (Drainage outlet)

[0075] Drain outlet 16 is an opening connected to drainage flow path 26 and discharges the water flowing in the water softening device 1 to the outside of the device.

[0076] During the raw water separation section cleaning process described later, drain outlet 16 discharges the raw water that has flowed in separation section 14 and been used in the backwashing of separation section 14 to the outside of the device. More specifically, during the raw water separation section cleaning process described later, drain outlet 16 discharges the water that has flowed in flow path 7, bypass flow path 29, on / off valve 33, flow path 8, on / off valve 37, second supply flow path 23, separation section 14, on / off valve 43, on / off valve 44, and drain flow path 26, together with the precipitates that have separated in separation section 14, to the outside of the device.

[0077] In addition, during the reclaimed water replacement process described later, the drain outlet 16 will discharge the water that has flowed in the neutralization tank 4, the second recovery flow path 24, the water storage tank 15, the water pump 19, and the electrolysis cell 12 to the outside of the device.

[0078] (Control Department)

[0079] The control unit 17 controls the softening process of raw water containing hardness components. Additionally, the control unit 17 controls the regeneration of 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. Furthermore, the control unit 17 controls the backwashing of the raw water separation section 14, utilizing the raw water separation section. Additionally, the control unit 17 controls the replacement of regenerated water discharged from the circulating flow path 20 formed during regeneration. Moreover, the control unit 17 controls the switching between softening, regeneration, raw water separation section cleaning, and regenerated water replacement processes in the softening unit 1. The control unit 17 also includes a current detection unit 18.

[0080] The current detection unit 18 detects the current value of the water pump 19 during the regeneration process. Information about the detected current value is sent to the control unit 17 and used to determine the switching of each process in the water softening device 1.

[0081] It should be noted that the control unit 17 is a computer system with a processor and memory. Furthermore, the computer system functions as a control unit by executing a program stored in the memory via the processor. The program executed by the processor is here assumed to be pre-recorded in the computer system's memory, but it can also be provided via a non-temporary recording medium such as a memory card, or via an electrical communication line such as the Internet.

[0082] In addition, when switching between water softening treatment, regeneration treatment, raw water separation unit cleaning treatment and regenerated water replacement treatment, the control unit 17 controls the operation of the electrode 13, the water pump 19, and multiple on / off valves (on / off valves 31 to 39 and 42 to 45), and performs the switching and each treatment.

[0083] (Flow path)

[0084] (Circular flow path)

[0085] Next, refer to Figure 2 The circulating flow path 20 formed during the regeneration process of the water softening device 1 will be explained. Figure 2 This is a structural diagram showing the circulation path 20 of the water softening device 1.

[0086] like Figure 2 As shown, in the water softening device 1, the electrolytic cell 12 constituting the regeneration device 6 and the water storage tank 15 are connected by a water supply path 25. Furthermore, the electrolytic cell 12 and the water storage tank 15 are connected to the flow paths 7, 8, and 9 from the inlet 2 to the outlet 5 by a first supply flow path 21, a first recovery flow path 22, a second supply flow path 23, and a second recovery flow path 24, respectively. In the water softening device 1, a circulation flow path 20 is formed by combining multiple flow paths. It should be noted that flow path 8 is connected to each flow path from the upstream side in the order of the first recovery flow path 22, the second supply flow path 23, and the bypass flow path 29.

[0087] The circulation path 20 includes a first circulation path 20a for water pumped by the pump 19 from the storage tank 15 to flow in the softening tank 3, and a second circulation path 20b for water pumped by the pump 19 from the storage tank 15 to flow in the neutralization tank 4.

[0088] The first circulation path 20a is as follows: Figure 2 As shown by the white arrow, the water pumped by the water pump 19 from the water storage tank 15 circulates through the electrolysis tank 12 and the softening tank 3 and returns to the water storage tank 15. More specifically, the first circulation path 20a is a path that circulates the water pumped by the water pump 19 from the water storage tank 15 in the following order: water delivery path 25, electrolysis tank 12, first supply path 21, on / off valve 35, softening tank 3, first recovery path 22, on / off valve 36, and water storage tank 15.

[0089] The second circulation path 20b is as follows: Figure 2(Black arrow) As shown, the water pumped by the water pump 19 from the storage tank 15 circulates through the electrolysis tank 12 and the neutralization tank 4 and returns to the storage tank 15. More specifically, the second circulation path 20b circulates the water pumped by the water pump 19 from the storage tank 15 in the following order: water supply path 25, electrolysis tank 12, second supply path 23, on / off valve 42, on / off valve 43, separation section 14, on / off valve 37, on / off valve 33, neutralization tank 4, second recovery path 24, on / off valve 38, and storage tank 15. The first supply path 21 supplies acidic electrolyzed water from the electrolysis tank 12 to the softening tank 3. The first recovery path 22 recovers water containing hardness components that has passed through the softening tank 3 back to the storage tank 15. Additionally, the second supply path 23 supplies alkaline electrolyzed water from the electrolyzer 12 to the neutralization tank 4. The second recovery path 24 recovers water that has passed through the neutralization tank 4 to the storage tank 15. The bypass path 29 supplies raw water to the neutralization tank 4 without passing through the softening tank 3.

[0090] The first supply flow path 21 is a flow path that supplies acidic electrolyzed water from the electrolyzer 12 to the softening tank 3, and an on / off valve 35 is provided in this flow path. That is, the softening device 1 has a first supply flow path 21 that can draw out acidic electrolyzed water from the electrolyzer 12 and transport it to the upstream side of the softening tank 3.

[0091] Furthermore, the first recovery flow path 22 is a flow path that recovers water containing hardness components that has passed through the water softening tank 3 to the water storage tank 15, and an on / off valve 36 is provided in this flow path. That is, the water softening device 1 has a first recovery flow path 22 that can connect the upstream side of the water storage tank 15 to the downstream side of the water softening tank 3.

[0092] The second supply flow path 23 is the flow path that supplies alkaline electrolyzed water from the electrolyzer 12 to the neutralization tank 4 via the separation section 14 during the regeneration process described later. This flow path is equipped with the separation section 14, on / off valves 42 and 43, and on / off valve 37. Specifically, the water softening device 1 uses the separation section 14 to separate the hardness components contained in the alkaline electrolyzed water drawn from the electrolyzer 12, and has a second supply flow path 23 capable of conveying the alkaline electrolyzed water with separated precipitates to the upstream side of the neutralization tank 4. It should be noted that the second supply flow path 23 is connected to the flow path 8 at a position downstream of the first recovery flow path 22. This is to suppress the mixing of acidic electrolyzed water discharged from the water softening tank 3 and alkaline electrolyzed water from the electrolyzer 12 during the regeneration process described later. That is, the flow path 8 is connected sequentially to the first recovery flow path 22 and the second supply flow path 23 from the upstream side.

[0093] Furthermore, the second recovery flow path 24 is a flow path that recovers water that has passed through the neutralization tank 4 to the water storage tank 15, and an on / off valve 38 is provided in this flow path. That is, the water softening device 1 has a second recovery flow path 24 that can connect the upstream side of the water storage tank 15 to the downstream side of the neutralization tank 4.

[0094] Here, in order to circulate water in the circulation path 20, an on / off valve 31 is provided downstream of the inlet 2 in the flow path 7. Furthermore, by closing the on / off valve 31 and opening the on / off valve 35, the first supply flow path 21 is connected upstream of the softening tank 3. This allows acidic electrolyzed water from the electrolyzer 12 to be supplied to the softening tank 3.

[0095] Furthermore, in the flow path 8, an on / off valve 32 is provided downstream of the first recovery flow path 22 and upstream of the second supply flow path 23. By closing the on / off valve 32 and opening the on / off valve 36, the first recovery flow path 22 is connected downstream of the softening tank 3. Thus, in the softening device 1, water (acidic electrolyzed water containing hardness components) that has flowed in the softening tank 3 can be recovered to the storage tank 15.

[0096] Furthermore, by closing the on / off valves 32 and 45 and opening the on / off valves 33, 37, 42, and 43, a second supply flow path 23 is connected to the upstream side of the neutralization tank 4. Thus, in the water softening device 1, alkaline electrolyzed water from the electrolyzer 12 can flow to the separation section 14 and be supplied to the neutralization tank 4.

[0097] Furthermore, in flow path 9, an on / off valve 34 is provided downstream of neutralization tank 4. By closing on / off valve 34 and opening on / off valve 38, a second recovery flow path 24 is connected downstream of neutralization tank 4. This allows water (alkaline electrolyzed water containing anions) that has passed through the second recovery flow path 24 to be recovered to storage tank 15.

[0098] Furthermore, by setting the on / off valve 34 to closed, the circulation of water into the circulation path 20 can be started. Conversely, by setting the on / off valve 34 to open, the circulation of water into the circulation path 20 can be stopped.

[0099] Additionally, in the water supply path 25, an on / off valve 39 is provided on the downstream side of the water storage tank 15 (at the position between the water storage tank 15 and the water pump 19). By setting the on / off valve 39 to closed, water can be stored in the water storage tank 15. Furthermore, by setting the on / off valve 39 to open, water can be supplied to the water supply path 25.

[0100] (Cleaning flow path for raw water separation section)

[0101] Next, refer to Figure 3 The raw water separation section cleaning flow path 27 formed during the cleaning process of the separation section of the water softening device 1 will be explained. Figure 3 This is a structural diagram showing the cleaning flow path 27 of the raw water separation section of the water softening device 1.

[0102] like Figure 3 As shown, the raw water separation unit cleaning flow path 27 is composed of various flow paths connecting the inlet 2, the separation unit 14, and the drain outlet 16. The raw water separation unit cleaning flow path 27 supplies raw water to the separation unit 14 without passing through the softening tank 3. More specifically, the raw water separation unit cleaning flow path 27 allows raw water flowing in from the inlet 2 to circulate in the bypass flow path 29, the separation unit 14, and the drain flow path 26, and to be discharged from the drain outlet 16.

[0103] The bypass flow path 29 is a flow path that bypasses the softening tank 3 and connects flow path 7 to flow path 8. One end of the bypass flow path 29 is connected to flow path 7 downstream of the on / off valve 31 and upstream of the connection point between the first supply flow path 21 and flow path 7. The other end of the bypass flow path 29 is connected to flow path 8 downstream of the on / off valve 33 and upstream of the neutralization tank 4. An on / off valve 45 is provided in the bypass flow path 29.

[0104] That is, the raw water introduced from the inlet 2 flows through the flow path 7 and the bypass flow path 29 and is supplied to the flow path 8. Furthermore, by closing the on / off valves 32, 34, and 38 and opening the on / off valves 33 and 37, the inlet 2 is directly connected to the upstream side of the separation section 14.

[0105] Additionally, the drainage path 26 is a path for discharging water from the downstream side of the separation section 14 or the cathode side of the electrolytic cell 12 to the drain outlet 16. On / off valves 42 and 44 are provided in the drainage path 26. That is, by opening the on / off valves 43 and 44, the water softening device 1 can discharge water from the downstream side of the separation section 14 to the drain outlet 16. Furthermore, by opening the on / off valves 42 and 44, water can be discharged from the cathode side of the electrolytic cell 12 to the drain outlet 16. In the raw water separation section cleaning path 27, the on / off valve 42 is closed, and the on / off valves 43 and 44 are opened.

[0106] That is, the raw water separation section cleaning flow path 27 is as follows: Figure 3 As shown by the slash arrow, the raw water introduced from inlet 2 flows in the following sequence: flow path 7, bypass flow path 29, flow path 8, second supply flow path 23, separation section 14, on / off valve 43, on / off valve 44, and drainage flow path 26, and is discharged from drain outlet 16 to the outside of the device. The raw water separation section cleaning flow path 27 is used during the raw water separation section cleaning process described later.

[0107] (Reclaimed water flow path replacement)

[0108] Next, refer to Figure 4 The reclaimed water replacement flow path 30 formed during the reclaimed water replacement treatment in the water softening device 1 will be explained. Figure 4 This is a structural diagram showing the reclaimed water replacement flow path 30 of the water softening device 1.

[0109] How to replace the flow path 30 in reclaimed water Figure 4 As shown by the horizontal arrow, the flow path allows water introduced from inlet 2 to circulate through neutralization tank 4, storage tank 15, water pump 19, and electrolysis cell 12, and it is also a flow path that uses the flowing water to replace the reclaimed water remaining in the flow path. More specifically, it is a flow path that allows water introduced from inlet 2 to circulate in the order of flow path 7, bypass flow path 29, and after passing through neutralization tank 4, it to circulate in the order of second recovery flow path 24, storage tank 15, water pump 19, electrolysis cell 12, on / off valve 42, on / off valve 44, and drainage flow path 26, and to be discharged from drain outlet 16 to the outside of the device. During the reclaimed water replacement process described later, reclaimed water is used to replace flow path 30.

[0110] The above describes the structure of water softening device 1.

[0111] Next, the operation of the water softening device 1 will be explained.

[0112] (Water softening treatment, regeneration treatment, and treatment to remove hardness components)

[0113] First, refer to Figure 5 The regeneration process, hardness component discharge process, and softening process of the water softening device 1, which starts with regeneration treatment, are explained. Figure 5 This is a diagram showing the state of the water softening device 1 during operation.

[0114] In regeneration treatment, hardness component discharge treatment, and water softening treatment, control unit 17, as shown... Figure 5 As shown, the flow is controlled by switching the on / off valves 31 to 39 and 42 to 45, the electrode 13 of the electrolytic cell 12, and the water pump 19 to achieve a predetermined flow state.

[0115] here, Figure 4 The "connected" fields indicate the states of the valve being "open," the electrode 13 being energized, and the water pump 19 being activated. Empty fields indicate the states of the valve being "closed," the electrode 13 not being energized, and the water pump 19 being stopped.

[0116] (Regeneration Processing)

[0117] First, refer to Figure 4The columns for "When water is injected" and "When regeneration is performed" describe the operation of the regeneration device 6 of the water softening device 1 during the regeneration process.

[0118] In the water softening device 1, the cation exchange capacity of the softening tank 3, filled with the weakly acidic cation exchange resin 10, decreases or disappears with continuous use. That is, after all the hydrogen ions of the functional groups of the cation exchange resin have been exchanged with calcium or magnesium ions, which are hardness components, ion exchange can no longer occur. When this state is reached, the hardness component is contained in the treated water. Therefore, in the water softening device 1, the softening tank 3 and the neutralization tank 4 need to be regenerated by the regeneration device 6.

[0119] Therefore, the water softening device 1 performs regeneration treatment once within a specified period (e.g., one day (24 hours)) and the control unit 17 determines the time period during which regeneration treatment can be performed.

[0120] First, such as Figure 5 As shown, when water is injected, on / off valves 31 and 36 are opened. Thus, under the pressure of the raw water, the softening device 1 introduces raw water from the inlet 2 through the softening tank 3 into the storage tank 15. At this time, on / off valves 32-35, 37-39, and 42-45 are closed. A predetermined amount of water corresponding to the capacity of the softening device 1 is stored in the storage tank 15, thereby ensuring the water volume for regeneration device 6 during regeneration.

[0121] Next, during regeneration, when the settings are configured to close on / off valves 31, 32, 34, 44, and 45, and open on / off valves 33, 35 to 39, 42, and 43, as follows: Figure 2 As shown, a first circulation path 20a and a second circulation path 20b are formed respectively. When the electrodes 13 of the electrolytic cell 12 and the water pump 19 are operated, the water stored in the water storage tank 15 circulates in the first circulation path 20a and the second circulation path 20b respectively.

[0122] At this time, the acidic electrolyzed water generated by the electrolyzer 12 is transported into the softening tank 3 through the first supply flow path 21 and flows through the weakly acidic cation exchange resin 10 inside. That is, by allowing the acidic electrolyzed water to flow 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. As a result, the weakly acidic cation exchange resin 10 is regenerated. Afterward, 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 22. That is, the acidic electrolyzed water containing cations that has flowed through the weakly acidic cation exchange resin 10 is recovered into the water storage tank 15 via the first recovery flow path 22.

[0123] On the other hand, the alkaline electrolyzed water generated by the electrolyzer 12 is transported into the neutralization tank 4 through the second supply flow path 23 and the separation section 14, and flows through the weakly basic anion exchange resin 11 inside. That is, by allowing the alkaline electrolyzed water to flow through the weakly basic anion exchange resin 11, the anions adsorbed on the weakly basic anion exchange resin 11 undergo an ion exchange reaction with the hydroxide ions contained in the alkaline electrolyzed water. As a result, the weakly basic anion exchange resin 11 is regenerated. Afterwards, the alkaline electrolyzed water containing anions that has flowed through the weakly basic anion exchange resin 11 flows into the second recovery flow path 24. That is, the alkaline electrolyzed water containing anions that has flowed through the weakly basic anion exchange resin 11 is recovered into the water storage tank 15 via the second recovery flow path 24.

[0124] Furthermore, in the water storage tank 15, the acidic electrolyzed water containing cations recovered from the water softening tank 3 is mixed with the alkaline electrolyzed water containing anions recovered from the neutralization tank 4 and neutralized.

[0125] At this point, acidic electrolyzed water containing cations (hardness components) is mixed with alkaline electrolyzed water containing anions, causing the hardness components to react with the hydroxide ions in the alkaline electrolyzed water to produce precipitates. However, at least in the initial stage of the regeneration process, the amount of hydroxide ions in the alkaline electrolyzed water flowing into the neutralization tank 4 is less than the amount of hardness components released from the softening tank 3, making it difficult for precipitates to form. Therefore, the hardness components in the neutralized electrolyzed water are sent to the electrolysis tank 12 as is.

[0126] Then, the electrolyzed water mixed in the water storage tank 15 is introduced back into the electrolytic cell 12 through the water supply path 25. And the introduced water is electrolyzed again in the electrolytic cell 12.

[0127] As described above, water electrolysis is performed in the electrolytic cell 12. Near the cathode, a large amount of hydroxide ions are generated through electrolysis, thus creating a state where precipitates are easily formed. That is, hardness components (e.g., calcium ions, magnesium ions) in the water supplied from the water storage tank 15 move towards the cathode side and react with hydroxide ions to form precipitates. Furthermore, the alkaline electrolyzed water containing the precipitates is sent to the second supply flow path 23 and flows into the separation section 14.

[0128] Within the separation section 14, alkaline electrolyzed water (treated water) is obtained, in which the precipitates contained in the alkaline electrolyzed water are separated and the hardness components are removed. Furthermore, the acidic electrolyzed water obtained by re-electrolysis in the electrolytic cell 12 and the alkaline electrolyzed water obtained by re-electrolysis in the electrolytic cell 12 and in which the precipitates have been separated by the separation section 14 are respectively supplied for the regeneration of the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11.

[0129] Here, a problem with not providing the separation unit 14 is that, during regeneration, hardness components released from the softening tank 3 react with alkaline electrolyzed water in the electrolyzer, generating precipitates that flow into and accumulate in the neutralization tank 4. That is, when softening treatment is restarted while precipitates are accumulated in the neutralization tank 4, the precipitates react with hydrogen ions released from the softening tank 3, resulting in hardness components and reduced softening performance. As a countermeasure, in this embodiment, the separation unit 14 separates the precipitates generated in the electrolyzer 12, thereby suppressing the accumulation of precipitates caused by hardness components inside the neutralization tank 4.

[0130] However, as the regeneration process progresses, the precipitates separated from the separation section 14 gradually accumulate within it. Consequently, the pressure loss in the separation section 14 increases. Although the circulation path 20 is supplied with constant energy by the water pump 19, the increased pressure loss in the separation section 14 leads to a gradual decrease in the flow rate of alkaline electrolyzed water supplied to the neutralization tank 4 as the regeneration process progresses, making it difficult to complete the regeneration process in the neutralization tank 4. Therefore, countermeasures are needed.

[0131] Therefore, in this embodiment, during the regeneration process of the water softening device 1, the current value of the water pump 19 is detected by the current value detection unit 18, and corresponding to the detected current value, the control unit 17 controls the transfer from regeneration process to hardness component discharge process. (Refer to...) Figure 6 The current value detection performed by the current value detection unit 18 and the transfer from regeneration treatment to hardness component discharge treatment performed by the control unit 17 will be explained. Figure 6 This is a graph showing the performance curve of the water pump 19 of the water softening device 1. Figure 6 (a) is a graph showing the relationship between flow rate and delivery pressure. Figure 6 (b) is a graph showing the relationship between flow rate and current value.

[0132] like Figure 6 As shown in (a), after the regeneration process has just begun (T1), no precipitates accumulate in the separation section 14, so the water pump 19 delivers electrolyzed water to the circulation path 20 at a first water delivery pressure P1. When the flow rate immediately downstream of the separation section 14 at this time is set to the first flow rate Q1, the first flow rate Q1 stabilizes. Furthermore, when the current value of the water pump 19 at this time is set to I1, as... Figure 6 As shown in (b), the first current value I1 is stable. During the regeneration process, as the regeneration of the weakly acidic cation exchange resin 10 in the softening tank 3 progresses (T2), the hardness in both the acidic and alkaline electrolyzed water increases, and precipitates are continuously generated in the alkaline electrolyzed water. The generated precipitates are captured by the separation section 14, and thus, as the regeneration process progresses, precipitates gradually accumulate in the separation section 14. When a blockage occurs in a part of the separation section 14 due to the accumulation of precipitates, the pressure loss in the separation section 14 increases. When the pressure loss in the separation section 14 increases, the pressure of the water in the circulation path 20 delivered by the water pump 19 increases, therefore, as Figure 6 As shown in (a), the pressure of the water pump 19 increases and becomes the second water delivery pressure P2. At this time, the flow rate after the separator 14 decreases and becomes the second flow rate Q2. Furthermore, due to the decrease in flow rate, therefore... Figure 6 As shown in (b), the current value of the water pump 19 decreases and becomes the second current value I2. That is, the flow rate change after the separation section 14 can be determined based on the change in the current value detected by the current value detection unit 18.

[0133] The current value detected by the current value detection unit 18 is used to determine the transition from regeneration treatment to hardness component removal treatment performed by the control unit 17. If the second current value I2 is above a predetermined value, the control unit 17 continues the regeneration treatment. On the other hand, if the second current value I2 is below the predetermined value, the control unit 17 controls the water softening device 1 to temporarily stop the regeneration treatment and transition to hardness component removal treatment. The predetermined value of the second current value I2 is, for example, the current value when the flow rate immediately following the separation unit 14 decreases to a constant value, and can be a current value set based on the evaluation results of previously conducted experiments. For example, if the flow rate at the beginning of the regeneration treatment is 2 L / min, the predetermined value can also be set as the current value when the flow rate decreases to 0.5 L / min. In this way, by detecting the current value of the water pump 19, the decrease in flow rate of the separation unit 14 can be monitored, and hardness component removal treatment can be performed at the appropriate time. Therefore, clogging of the separation unit 14 can be suppressed, and alkaline electrolyzed water can circulate smoothly in the second circulation path 20b, which is the path of the separation unit 14. Therefore, the regeneration process of neutralization tank 4 can be carried out smoothly.

[0134] During the transfer to the hardness component discharge process, the control unit 17 stops the operation of the electrode 13 and the water pump 19, closes the on / off valves 32, 34-36, 38, 39, and 42, and opens the on / off valves 31, 33, 37, and 43-45. This transfers the process from regeneration to hardness component discharge.

[0135] (Hardness component removal treatment)

[0136] In this embodiment, the hardness component discharge treatment includes raw water separation section cleaning treatment and reclaimed water replacement treatment. The reclaimed water replacement treatment is performed after the raw water separation section cleaning treatment.

[0137] The reasons for performing hardness component removal treatment are explained. As the regeneration process progresses, the concentration of hardness components in the acidic electrolyzed water containing hardness components recovered from the softening tank 3 gradually increases. Therefore, the concentration of hardness components in the regenerated water in the storage tank 15 increases. Consequently, the concentration of hardness components in the acidic electrolyzed water transported from the electrolyzer 12 to the softening tank 3 increases, making it difficult to release the hardness components from the weakly acidic cation exchange resin 10. Therefore, the amount of hardness components that can be recovered from the softening tank 3 decreases, resulting in slower progress or incomplete regeneration. Furthermore, as explained in the regeneration process section, blockage of the separation section 14 may occur due to precipitates forming in it. For these reasons, it is necessary to reduce the amount of hardness components in the circulation path 20, therefore, hardness component removal treatment is performed.

[0138] ((Cleaning treatment of raw water separation section))

[0139] When the regeneration process is temporarily stopped, the water softening unit 1 is transferred to the raw water separation section for cleaning. Here, the raw water separation section cleaning process refers to the process of introducing raw water from the downstream side of the separation section 14 and discharging the precipitates accumulated in the separation section 14 together with the raw water. As a result, the separation section 14 can be backwashed.

[0140] Next, refer to Figure 5 The "Cleaning of Raw Water Separation Unit" section describes the operation during the cleaning process of the raw water separation unit performed by the water softening device 1.

[0141] like Figure 5As shown, during the raw water separation section cleaning process, the softening device 1 opens valves 31, 33, 37, and 45, and opens valves 43 and 44 in a flow path that allows water to flow from the separation section 14 to the drainage path 26. This creates a raw water separation section cleaning flow path 27 in the softening device 1, enabling the cleaning of the separation section 14. At this time, valves 35, 36, 38, 39, and 42 are closed.

[0142] Specifically, in the cleaning process of the raw water separation section, such as Figure 3 As shown, the supplied raw water flows from inlet 2 through flow path 7 into bypass flow path 29. Next, since on / off valve 33 is open and on / off valve 32 is closed, the raw water flowing in bypass flow path 29 flows through flow path 8 and second supply flow path 23, and flows into separation section 14. By allowing the raw water to flow into separation section 14, the precipitates caused by hardness components captured by separation section 14 flow out of separation section 14 along with the raw water.

[0143] Furthermore, since the on / off valves 43 and 44 are open, the raw water containing precipitates flowing from the separation section 14 flows through the drainage path 26 and is discharged out of the device from the drain outlet 16. This removes the precipitates captured by the separation section 14 and cleans the separation section 14. Therefore, the blockage of the separation section 14 can be eliminated by the raw water separation section cleaning process, increasing the water flow rate of the separation section 14 compared to before the raw water separation section cleaning process. It should be noted that, to confirm the elimination of the blockage in the separation section 14, it is sufficient to check the increase in the current value of the water pump after the regeneration process has restarted compared to before the raw water separation section cleaning process was performed.

[0144] Furthermore, the cleaning process of the raw water separation section is set to end when a constant time (e.g., 5 minutes) has elapsed since the start of the replacement process. This constant time is the time required to discharge the precipitates accumulated in the separation section 14 along with the raw water, and can be set using the evaluation results based on a pre-conducted cleaning experiment.

[0145] When the raw water separation section cleaning process is completed, in order to replace the reclaimed water with high hardness concentration in the water storage tank 15 with the raw water, the on / off valves 31, 38, 39, 42, 44 and 45 are opened, and the on / off valves 32 to 37 and 43 are closed, switching to reclaimed water replacement process.

[0146] (Reclaimed water replacement treatment)

[0147] The reclaimed water replacement treatment refers to the process of discharging reclaimed water with a high concentration of hardness components remaining in the water softening unit 1 to the outside of the unit. In particular, reclaimed water with a high concentration of hardness components remains in the water storage tank 15, so the reclaimed water in the water storage tank 15 is replaced with water with a low concentration of hardness components.

[0148] Next, refer to Figure 5 The "When Reclaimed Water is Replaced" section describes the operation during the reclaimed water replacement process performed by the water softening unit 1.

[0149] like Figure 5 As shown, in the reclaimed water replacement process, the softening water unit 1 opens on-off valves 31, 38, and 45, and opens on-off valves 39, 42, and 44 in a flow path that allows water to flow from the storage tank 15 to the drainage path 26. This forms a reclaimed water replacement flow path 30 in the softening water unit 1. At this time, on-off valves 32 to 37 and on-off valve 43 are closed.

[0150] Specifically, such as Figure 4 As shown, in the reclaimed water replacement process, the supplied raw water flows from inlet 2 through flow path 7 and into bypass flow path 29. Next, since on / off valve 38 is open and on / off valves 33 and 34 are closed, the raw water flowing in bypass flow path 29 flows through flow path 9 and second recovery flow path 24, and flows into storage tank 15. Furthermore, since on / off valves 39, 42, and 44 are open, the raw water flowing in storage tank 15 flows through drainage flow path 26 and is discharged from drain outlet 16 to the outside of the device. This reduces the amount of hardness in the reclaimed water within the regeneration process path, thus reducing the amount of hardness in the reclaimed water flowing into electrolyzer 12 when regeneration is restarted. Additionally, it reduces the amount of precipitates generated by the reaction of hardness in the reclaimed water with hydroxide ions moving towards the cathode side of electrolyzer 12, making it difficult to reduce the flow rate of separation section 14. Therefore, the regeneration of ion exchange resins can be carried out without any obstruction, which can shorten the time required for regeneration.

[0151] In addition, the end of the reclaimed water replacement process is set at a constant time (e.g., 2 minutes) elapsed from the start of the replacement process. This time is set based on the actual design and is the time required for all water to be discharged from the inlet 2 through the bypass path 29 to the outlet 16.

[0152] When the reclaimed water replacement treatment is completed, in order to restart the temporarily stopped regeneration treatment, the softening water unit 1 closes the on-off valves 31, 32, 34, 44 and 45, and opens the on-off valves 33, 35 to 39, and restarts the regeneration treatment.

[0153] It should be noted that the end of the regeneration process is defined as a constant time (e.g., 2 hours) elapsed from the start of the regeneration process, excluding the time required for hardness component discharge and valve switching. Multiple raw water separation section cleaning processes or reclaimed water replacement processes can also be performed during the regeneration process (until its completion). In this case, the regeneration process ends when the total time of multiple regeneration processes meets the constant time requirement. When the regeneration process ends in the softening water unit 1, the operation of electrode 13 and water pump 19 is stopped, valves 31 to 34 are opened, and valves 35 to 39 and 42 to 45 are closed, transitioning to the softening water treatment process.

[0154] (Water softening treatment)

[0155] Reference Figure 5 The “Softening process” section describes the operation of the softening process performed by the softening device 1.

[0156] like Figure 5 As shown, in the water softening process, with the on / off valves 31 to 33 open, the on / off valve 34 located at the water intake 5 is opened in the water softening device 1. Thus, in the water softening device 1, municipal water (raw water containing hardness components) flows from the outside into the water softening tank 3 and the neutralization tank 4, allowing softened water (neutral soft water) to be taken out from the water intake 5.

[0157] Specifically, in the water softening process, under the pressure of the municipal water supply, raw water is supplied from inlet 2 through flow path 7 to softening tank 3. The raw water supplied to softening tank 3 flows through a weakly acidic cation exchange resin 10 within the softening tank 3. At this time, cations in the raw water that constitute hardness are adsorbed by the weakly acidic cation exchange resin 10, releasing hydrogen ions (ion exchange). Thus, by removing cations from the raw water, it is softened. The softened water further flows through flow path 8 into neutralization tank 4. In neutralization tank 4, hydrogen ions contained in the softened water are adsorbed by a weakly basic anion exchange resin 11. That is, hydrogen ions are removed from the treated softened water, thereby raising the lowered pH, making it softened neutral water for domestic use, and then it is taken out from water inlet 5 through flow path 9. At this time, the on / off valves 35-39 and 42-45 are all closed. Additionally, the operation of the electrodes 13 of the electrolytic cell 12 and the water pump 19 also ceases.

[0158] Furthermore, the water softening device 1 stops the water softening process and performs the regeneration process described above when the time period is determined by the control unit 17 or when the water softening process exceeds a constant time.

[0159] As described above, the water softening unit 1 repeatedly performs regeneration treatment, raw water separation unit cleaning treatment, reclaimed water replacement treatment, and water softening treatment.

[0160] The softening device 1 according to Embodiment 1 can enjoy the following effects.

[0161] (1) The water softening device 1 includes a water softening tank 3, a neutralization tank 4, an electrolysis tank 12, a water pump 19, a current detection unit 18, and a control unit 17. The water softening tank 3 uses a weakly acidic cation exchange resin 10 to soften raw water containing hardness components and chloride ions to generate soft water. The neutralization tank 4 uses a weakly basic anion exchange resin 11 to neutralize the pH of the soft water (generated from the water softening tank 3) that has passed through the water softening tank 3. The electrolysis tank 12 generates acidic electrolyzed water that regenerates the weakly acidic cation exchange resin 10 of the water softening tank 3 and alkaline electrolyzed water that regenerates the weakly basic anion exchange resin 11 of the neutralization tank 4. The water pump 19 delivers the alkaline electrolyzed water to the neutralization tank 4. The current detection unit 18 detects the current value of the water pump 19 during operation. Based on the current value detected by the current value detection unit 18, the control unit 17 controls the regeneration process, which involves at least one of regeneration of the weakly acidic cation exchange resin 10 using acidic electrolyzed water or regeneration of the weakly basic anion exchange resin 11 using alkaline electrolyzed water. During regeneration, the control unit 17 continues the regeneration process if the current value of the water pump 19 detected by the current value detection unit 18 is above a predetermined value. Conversely, if the current value of the water pump 19 detected by the current value detection unit 18 is below a predetermined value, the control unit 17 stops the regeneration process and switches to a process for discharging hardness components from the device to the outside.

[0162] Therefore, a decrease in the flow rate of the separation section 14 can be detected, and the hardness components in the circulation path 20 can be discharged out of the device. This avoids situations where the separation section 14 becomes clogged, preventing regeneration from progressing or requiring excessive time to complete the regeneration process. In other words, a water softening device 1 can be provided that can discharge hardness components from the device at the appropriate time and shorten the time required for regeneration.

[0163] (2) The water softening device 1 also includes a separation section 14. The separation section 14 is provided in the flow path that connects the electrolysis cell 12 and the neutralization cell 4, and separates the precipitates caused by the hardness components contained in the alkaline electrolyzed water introduced into the electrolysis cell 12. Furthermore, during the raw water separation section cleaning process, the raw water from the inlet 2 is allowed to flow into the separation section 14 from the downstream side.

[0164] Therefore, the separation section 14 can be backwashed using raw water, and the precipitates containing hardness components accumulated in the separation section 14 can be discharged out of the device along with the raw water. Consequently, the pressure loss in the separation section 14 can be reduced, and a sufficient amount of alkaline electrolyzed water can be supplied to the neutralization tank 4. Thus, the softening water device 1 can be made to perform regeneration treatment without any obstruction.

[0165] (3) In the regeneration process, the water softening device 1 introduces raw water into the water storage tank 15 and performs regeneration water replacement treatment. The regeneration water replacement treatment is the process of discharging the regeneration water with a high concentration of hardness components remaining in the water storage tank 15 to the outside of the device.

[0166] Therefore, the regenerated water, which contains a significant amount of hardness components released from the weakly acidic cation exchange resin 10 during regeneration, can be discharged outside the device. Consequently, the amount of hardness components in the regenerated water within the regeneration path is reduced, thus reducing the amount of hardness components in the regenerated water flowing into the electrolyzer during the next regeneration process. This also reduces the amount of precipitates generated by the reaction of the hardness components in the regenerated water with hydroxide ions moving towards the cathode side of the electrolyzer 12. Therefore, a water softening device 1 can be provided that enables smooth regeneration of the ion exchange resin and shortens the regeneration time required for the water softening device 1.

[0167] (Implementation Method 2)

[0168] Next, refer to Figure 7 The water softening apparatus 1a of Embodiment 2 of the present invention will be described. Figure 7 This is a conceptual diagram showing the structure of the water softening device 1a according to Embodiment 2.

[0169] The softening device 1a in Embodiment 2 differs from Embodiment 1 in that it introduces raw water into the softening tank 3 during the hardness component discharge treatment and discharges acidic electrolyzed water with a high concentration of hardness components remaining in the softening tank 3 to the outside of the device, and it uses the acidic soft water flowing in the softening tank 3 to clean the separation section 14. Apart from this, the structure and control of the softening device 1a are the same as those of the softening device 1 in Embodiment 1. Hereinafter, the content described in Embodiment 1 will be omitted as appropriate, and the differences from Embodiment 1 will be mainly explained.

[0170] (Flow path)

[0171] like Figure 7As shown, the water softening device 1a is configured with multiple on / off valves (on / off valves 31 to 39 and 42 to 44). These valves are respectively positioned at predetermined locations in multiple flow paths, and switch between an "open" and "closed" state in each flow path. Furthermore, the water softening device 1a does not have a flow path equivalent to the bypass flow path 29 in Embodiment 1. The water softening device 1a is configured to generate acidic soft water by circulating water through the water softening tank 3 via the flow path 8, instead of the bypass flow path 29, and supplying it to the separation unit 14.

[0172] The flow path 8 is connected sequentially to the first recovery flow path 22 and the second supply flow path 23 from the upstream side of the water softening treatment. That is, during the hardness component discharge treatment, the raw water introduced from the inlet 2 flows in the order of flow path 7, on / off valve 31, water softening tank 3, flow path 8, and on / off valve 32, and is supplied to the separation section 14 as acidic soft water.

[0173] Next, refer to Figure 8 The cleaning flow path 27a of the acid separation section in the water softening device 1a will be described. Figure 8 This is a structural diagram showing the cleaning flow path 27a of the acid separation section of the water softening device 1a in Embodiment 2.

[0174] like Figure 8 As shown, the acid separation section cleaning flow path 27a is composed of various flow paths connecting the inlet 2, the softening tank 3, the separation section 14, and the drain outlet 16. Specifically, the softening tank 3 is connected to the inlet 2 via flow path 7. The softening tank 3 is connected to the separation section 14 via flow path 8 and the second supply flow path 23. The separation section 14 is connected to the drain outlet 16 via the second supply flow path 23 and the drain flow path 26. The second supply flow path 23 is equipped with the separation section 14, an on / off valve 37, an on / off valve 42, and an on / off valve 43.

[0175] The acid separation section cleaning flow path 27a is a flow path that uses acidic soft water to clean the separation section 14, and it is also the flow path that supplies water during the acid separation section cleaning process. Specifically, the acid separation section cleaning flow path 27a is as follows: Figure 8 As shown by the slash arrow, the raw water introduced from the inlet 2 flows through the flow path 7 and the softening tank 3 in that order. After becoming acidic soft water in the softening tank 3, it flows through the flow path 8, the second supply flow path 23, and the separation section 14 in that order and is supplied to the separation section 14 for cleaning. It then flows through the on / off valve 43 and the drainage flow path 26 and is discharged out of the device from the drain outlet 16. That is, in the softening device 1a, it is configured such that during the acidic separation section cleaning process, the acidic soft water 14 flows from the downstream side of the separation section 14 and performs reverse cleaning relative to the separation section.

[0176] Next, refer to Figure 9 The process of replacing the reclaimed water flow path 30a in the water softening unit 1a is explained. Figure 9 This is a structural diagram showing the reclaimed water replacement flow path 30a of the water softening device in Embodiment 2.

[0177] like Figure 9 (As shown by the horizontal arrow) The reclaimed water replacement flow path 30a consists of various flow paths connecting the inlet 2, softening tank 3, neutralization tank 4, storage tank 15, water pump 19, electrolysis cell 12, and drain outlet 16. Specifically, the softening tank 3 is connected to the inlet 2 via flow path 7. The softening tank 3 is connected to the neutralization tank 4 via flow path 8. The neutralization tank 4 is connected to the storage tank 15 via the second recovery flow path 24. In addition, the storage tank 15 is connected to the water pump 19 in sequence with the electrolysis cell 12 via the water supply flow path 25. The electrolysis cell 12 is connected to the drain outlet 16 via the drain flow path 26.

[0178] The reclaimed water replacement flow path 30a is a flow path that uses raw water introduced from inlet 2 to replace the water remaining in the softening tank 3, neutralization tank 4, storage tank 15, water pump 19, and electrolysis tank 12, and is the flow path for supplying water during the reclaimed water replacement treatment. Specifically, it is a flow path in which the raw water introduced from inlet 2 flows in the order of flow path 7, softening tank 3, second recovery flow path 24, storage tank 15, water pump 19, and electrolysis tank 12, and then flows through on / off valve 42, on / off valve 44, and drainage flow path 26, and is discharged to the outside of the device from drain outlet 16.

[0179] (Regeneration treatment, acid separation unit cleaning treatment, reclaimed water replacement treatment, and water softening treatment)

[0180] (Regeneration Processing)

[0181] The operation of the regeneration device 6 in the water softening device 1a is the same as that in the water softening device 1 of Embodiment 1, therefore, the description of the operation during regeneration is omitted. In the water softening device 1a, during the progress of the regeneration process, the flow rate change after the separation section 14 can be monitored based on the change in the current value detected by the current value detection unit 18. The current value detected by the current value detection unit 18 is used to determine the transition from the regeneration process to the hardness component discharge process performed by the control unit 17. The control unit 17 continues the regeneration process if the second current value I2 is above a predetermined value. On the other hand, if the second current value I2 is below the predetermined value, the control unit 17 controls the water softening device 1a to temporarily stop the regeneration process and transition to the hardness component discharge process. That is, the operation of the electrode 13 and the water pump 19 is stopped, and the process transitions to the hardness component discharge process. In the hardness component discharge process shown in Embodiment 2, the acid separation section cleaning process and the regenerated water replacement process are performed sequentially. It should be noted that the specified value of the second current value I2, for example, is the current value when the flow rate immediately after the separation section 14 decreases to a constant value, and the current value set based on the evaluation results of the prior experiments can be used.

[0182] (Cleaning of the acid separation section)

[0183] When the regeneration process of the water softening unit 1a is temporarily stopped, it is transferred to the acid separation section for cleaning. Here, the acid separation section cleaning process refers to the process of discharging the acidic electrolyzed water with a high concentration of hardness components remaining in the water softening tank 3 to the outside of the unit and introducing raw water into the water softening tank 3.

[0184] Next, refer to Figure 10 The section on "Cleaning of the Acid Separation Section" describes the operation during the cleaning of the acid separation section performed by the water softening unit 1a. Figure 10 This is a diagram showing the state of the water softening device 1a in operation according to Embodiment 2.

[0185] In the water softening device 1a, such as Figure 10 As shown, during the acid separation section cleaning process, on / off valves 31, 32, 37, 43, and 44 are opened. This creates an acid separation section cleaning flow path 27a in the water softening device 1, enabling reverse cleaning of the separation section 14 using acidic soft water. At this time, on / off valves 33-36, 38, 39, and 42 are closed.

[0186] like Figure 8As shown, with valves 32 and 37 open and valves 33 and 36 closed, the acidic soft water from the softening tank 3 flows through the flow path 8 and the second supply flow path 23, and flows downstream of the water flow direction during regeneration into the separation section 14. By allowing the acidic soft water to flow into the separation section 14, the precipitates caused by hardness components captured by the separation section 14 react with the acidic soft water. Consequently, the precipitates caused by hardness components dissolve and become hardness components themselves, contained within the acidic soft water.

[0187] Furthermore, since the on / off valves 43 and 44 are open and the on / off valve 42 is closed, the acidic soft water delivered from the separation section 14 flows through the drainage path 26 and is discharged out of the device through the drain outlet 16. Therefore, the precipitates accumulated in the separation section 14 dissolve in the acidic soft water and are discharged out of the device together with the acidic soft water.

[0188] Furthermore, in the water softening unit 1a, when the acid separation unit cleaning process is completed, the regenerated water replacement process begins. Therefore, the on / off valves 31 to 33, 38, 39, 42 and 44 are opened, and the on / off valves 34 to 37 and 43 are closed.

[0189] The cleaning process of the acid separation section ends when a constant time (e.g., 5 minutes) has elapsed since the start of the replacement process. Here, the constant time is the time required to discharge the acidic electrolyzed water with a high concentration of hardness components remaining in the softening tank 3 to the outside of the device and to dissolve a constant amount of the precipitates captured by the separation section 14. This time is set based on the evaluation results of a pre-conducted cleaning experiment.

[0190] (Reclaimed water replacement treatment)

[0191] Next, refer to Figure 10 The "When Reclaimed Water is Replaced" section describes the operation during the reclaimed water replacement process performed by the water softening unit 1a.

[0192] In the water softening device 1a, such as Figure 10 As shown, during the reclaimed water replacement process, on / off valves 31 to 33 are opened. Additionally, during the reclaimed water replacement process, on / off valves 38, 39, 42, and 44 are opened such that the water flows from the neutralization tank 4 through the second recovery flow path to the drainage flow path 26. This forms a reclaimed water replacement flow path 30a in the water softening unit 1a. At this time, on / off valves 33 to 37 and on / off valve 43 are closed.

[0193] Specifically, in the process of reclaimed water replacement treatment, such as Figure 9As shown, under the pressure of the city's water supply, the supplied raw water flows from inlet 2 through flow path 7 into softening tank 3. Next, with valves 32 and 33 open and valves 36 and 37 closed, the raw water passing through softening tank 3 flows into neutralization tank 4. Afterward, the water passing through neutralization tank 4 flows through flow path 9 and second recovery flow path 24, and flows into storage tank 15. Furthermore, with valves 39, 42, and 44 open, the raw water flowing in storage tank 15 flows through water pump 19, electrolysis tank 12, and drainage flow path 26, and is discharged from drain outlet 16 to the outside of the device. This reduces the hardness content of the regenerated water in the regeneration process, enabling smooth regeneration of the ion exchange resin and shortening the regeneration time.

[0194] In addition, the end of the reclaimed water treatment is set at a constant time (e.g., 2 minutes) elapsed from the start of the replacement treatment. Here, the constant time is the time required for all water from inlet 2 to outlet 16 to be discharged, and can be set based on the actual design.

[0195] When the reclaimed water replacement treatment is completed, the water softening device 1a restarts the temporarily stopped regeneration treatment. Therefore, it closes the on / off valves 31, 32, 34, 44 and 45, and opens the on / off valves 33, 35 to 39, and restarts the regeneration treatment.

[0196] Subsequently, in the water softening unit 1, when the regeneration process is completed, the operation of electrode 13 and water pump 19 is stopped. It should be noted that the end of the regeneration process is defined as a constant time (e.g., 2 hours) elapsed from the start of the regeneration process, excluding the time required for hardness component removal and valve switching. Alternatively, multiple acid separation section cleaning processes or reclaimed water replacement processes may be performed during the regeneration process (until its completion). When the regeneration process is completed, the process transitions to water softening.

[0197] (Water softening treatment)

[0198] Regarding the water softening treatment, the content is the same as that described in Implementation Method 1, so detailed descriptions are omitted.

[0199] As described above, the water softening unit 1a repeatedly performs regeneration treatment, raw water separation unit cleaning treatment, reclaimed water replacement treatment, and water softening treatment.

[0200] In addition to the effects (2) obtained by Embodiment 1, the water softening device 1a according to Embodiment 2 can also enjoy the following effects.

[0201] (4) In the water softening device 1a, the raw water that has been flowing in the water softening tank 3 is configured to flow into the downstream side of the separation section 14 relative to the separation section 14, so as to perform acid separation section cleaning treatment.

[0202] Therefore, the raw water, which has become acidic soft water through the softening tank 3, flows into the downstream side of the separation section 14. The acidic soft water flows into the separation section 14, thus dissolving and discharging the precipitates containing hardness components that have formed in the separation section 14. This improves the cleaning efficiency of the separation section 14, allowing it to be transferred to reclaimed water replacement treatment in a shorter time.

[0203] (Implementation Method 3)

[0204] Next, refer to Figure 11 The water softening apparatus 1b of Embodiment 3 of the present invention will be described. Figure 11 This is a conceptual diagram showing the structure of the water softening device 1b of Embodiment 3 and the flow path 27b for discharging hardness components.

[0205] In Embodiment 3, the water softening device 1b differs from Embodiment 1 in that, during the hardness component discharge treatment, raw water is introduced into the water softening tank 3, and regenerated water containing a large amount of hardness components in the water softening tank 3 and the storage tank 15 is discharged out of the device. Simultaneously, acidic soft water circulating in the water softening tank 3 is used to clean the separation section 14. Apart from this, the structure and control of the water softening device 1b are the same as those of the water softening device 1 in Embodiment 1. Hereinafter, the content described in Embodiment 1 will be appropriately omitted, and the differences from Embodiment 1 will be mainly explained.

[0206] (Flow path)

[0207] Reference Figure 11 and Figure 12 The flow path in the water softening device 1b is described. Figure 12 This is a diagram showing the state of the water softening device in Embodiment 3 during operation.

[0208] like Figure 11 As shown, the water softening device 1b, like the water softening device 1, includes multiple on / off valves (on / off valves 31 to 39 and 42 to 45). These multiple on / off valves (on / off valves 31 to 39 and 42 to 44) are respectively positioned at predetermined locations in multiple flow paths, and switch between an "open" and "closed" state in each flow path.

[0209] like Figure 11(As shown by the slashed arrow) The acid separation section cleaning flow path 27b is composed of various flow paths connecting the inlet 2, the softening tank 3, the separation section 14, and the drain outlet 16. Specifically, the softening tank 3 is connected to the inlet 2 via flow path 7. Furthermore, the softening tank 3 is connected to the separation section 14 via flow path 8 and the second supply flow path 23. The separation section 14 is connected to the drain outlet 16 via the second supply flow path 23 and the drain flow path 26. The second supply flow path 23 is equipped with the separation section 14, an on / off valve 37, an on / off valve 42, and an on / off valve 43.

[0210] The acid separation section cleaning flow path 27b is a flow path that uses acidic soft water to clean the separation section 14, and it is also the flow path that supplies water during the acid separation section cleaning process. Specifically, the acid separation section cleaning flow path 27a is as follows: Figure 11 As shown by the slash arrow, the raw water introduced from the inlet 2 flows through the flow path 7 and the softening tank 3 in that order. After becoming acidic soft water in the softening tank 3, it flows through the flow path 8, the second supply flow path 23, and the separation section 14 in that order and is supplied for cleaning the separation section 14. It then flows through the on / off valve 43, the on / off valve 44, and the drainage flow path 26 and is discharged out of the device from the drain outlet 16. That is, in the softening device 1b, it is configured such that during the acidic separation section cleaning process, the acidic soft water flows from the downstream side of the separation section 14 and performs reverse cleaning relative to the separation section 14.

[0211] like Figure 11 (As shown by the horizontal arrow) The reclaimed water replacement flow path 30b consists of various flow paths connecting the inlet 2, neutralization tank 4, storage tank 15, water pump 19, electrolyzer 12, and drain outlet 16. Specifically, the neutralization tank 4 is connected to the inlet 2 via flow path 7, bypass flow path 29, and flow path 8. Furthermore, the neutralization tank 4 is connected to the storage tank 15 via the second recovery flow path 24. The storage tank 15 is connected to the water pump 19 in sequence to the electrolyzer 12 via the water supply flow path 25. The electrolyzer 12 is connected to the drain outlet 16 via the drain flow path 26.

[0212] In addition, such as Figure 11 As shown by the horizontal arrow, the reclaimed water replacement flow path 30b is a flow path that allows water introduced from inlet 2 to flow in the order of bypass flow path 29, neutralization tank 4, storage tank 15, water pump 19, and electrolysis cell 12. More specifically, it is a flow path that allows raw water introduced from inlet 2 to flow in the order of flow path 7 and bypass flow path 29, and after passing through neutralization tank 4, to flow in the order of second recovery flow path 24, storage tank 15, water pump 19, and electrolysis cell 12, and to flow through on / off valve 42, on / off valve 44, and drainage flow path 26 before being discharged from drain outlet 16 to the outside of the device.

[0213] (Regeneration treatment, hardness component removal treatment, and water softening treatment)

[0214] (Regeneration Processing)

[0215] The operation of the regeneration device 6 in the water softening device 1b is the same as that in the water softening device 1 of Embodiment 1, therefore, the description of the operation during regeneration is omitted. In the water softening device 1b, during the regeneration process, the flow rate change after the separation section 14 can be monitored based on the change in the current value detected by the current value detection unit 18. The current value detected by the current value detection unit 18 is used to determine the transition from regeneration process to hardness component discharge process performed by the control unit 17. The control unit 17 continues the regeneration process if the second current value I2 is above a predetermined value. On the other hand, if the second current value I2 is below the predetermined value, the control unit 17 controls the water softening device 1 to temporarily stop the regeneration process and transition to hardness component discharge process. That is, the operation of the electrode 13 and the water pump 19 is stopped, and the process transitions to hardness component discharge process. In the hardness component discharge process shown in Embodiment 3, acid separation section cleaning and regenerated water replacement processes are performed simultaneously. It should be noted that the specified value of the second current value I2, for example, is the current value when the flow rate immediately after the separation section 14 decreases to a constant value, and the current value set based on the evaluation results of the prior experiments can be used.

[0216] (Hardness component removal treatment)

[0217] When the regeneration process is temporarily stopped, the softening water unit 1b is transferred to the hardness component discharge process. The hardness component discharge process shown in this embodiment involves the raw water flowing simultaneously through both the acid separation section cleaning path 27b and the regenerated water replacement path 30b. Specifically, in the hardness component discharge process, raw water is introduced and simultaneously flows through two paths: the acid separation section cleaning path 27b, which discharges the precipitates from the separation section 14 along with the acidic electrolyzed water with a high concentration of hardness components remaining in the softening water tank 3, and the regenerated water replacement path 30b, which replaces the regenerated water in the neutralization tank 4, storage tank 15, water pump 19, and electrolysis tank 12 with raw water and discharges it to the outside of the unit. This cleans the separation section 14 and reduces the concentration of hardness components within the softening water unit 1b.

[0218] Next, refer to Figure 12 The "When hardness components are discharged" section describes the operation during the hardness component discharge process performed by the water softening device 1b.

[0219] In the water softening device 1b, such as Figure 11As shown, during the hardness component discharge treatment, valves 31, 32, 37, 43, and 44 are opened. This creates an acidic separation section cleaning flow path 27b in the water softening unit 1, enabling backwashing of the separation section 14 using acidic soft water. Furthermore, by opening valves 45, 38, 39, 42, and 44, a reclaimed water replacement flow path 30b is created in the water softening unit 1b, allowing the reclaimed water with a high hardness component concentration to be replaced with raw water. At this time, valves 33-36 and 39 are closed.

[0220] like Figure 11 As shown, in the acid separation section cleaning flow path 27b, since the on-off valves 32 and 37 are open, and the on-off valves 33 and 36 are closed, the acidic soft water supplied from the softening tank 3 flows through the flow path 8 and the second supply flow path 23, and flows into the separation section 14. By allowing the acidic soft water to flow into the separation section 14, the precipitates caused by hardness components captured by the separation section 14 react with the acidic soft water. As a result, the precipitates caused by hardness components dissolve, becoming hardness components themselves, and are contained in the acidic soft water.

[0221] Furthermore, since the on / off valves 43 and 44 are open, the acidic soft water sent from the separation section 14 flows through the drainage path 26 and is discharged out of the device through the drain outlet 16. At this time, before the acidic soft water reaches the separation section 14, the acidic electrolyzed water with a high concentration of hardness components remaining in the softening tank 3 during the regeneration process flows through the separation section 14 and is discharged out of the device through the drain outlet 16.

[0222] Furthermore, in the reclaimed water replacement flow path 30b, the supplied raw water flows from the inlet 2 through the flow path 7 into the bypass flow path 29. Next, since the on / off valve 38 is open and the on / off valves 33 and 34 are closed, the raw water that has passed through the bypass flow path 29 flows through the flow path 9 and the second recovery flow path 24 and flows into the storage tank 15. Also, since the on / off valves 39, 42, and 44 are open, the raw water that has flowed in the storage tank 15 flows through the drainage flow path 26 and is discharged from the drain outlet 16 to the outside of the device. This reduces the hardness content of the reclaimed water in the regeneration process path, thus enabling smooth regeneration of the ion exchange resin and shortening the regeneration time.

[0223] When the hardness component discharge treatment is finished, the water softening device 1b resumes the temporarily stopped regeneration treatment. Therefore, it closes the on / off valves 31, 32, 34, 44 and 45, and opens the on / off valves 33, 35 to 39.

[0224] Furthermore, the end of the hardness component discharge treatment is set at a constant time (e.g., 5 minutes) elapsed from the start of the hardness component discharge treatment. Here, the constant time is set to the maximum value of the time required to discharge the hardness component in the acid separation section cleaning flow path 27b or the reclaimed water replacement flow path 30b. The time required to discharge the hardness component in the acid separation section cleaning flow path 27b can be set based on the evaluation results of a pre-conducted cleaning experiment, which is the time required to discharge the acidic electrolyzed water with a high concentration of hardness component remaining in the softening tank 3 to the outside of the device and to dissolve a constant amount of the precipitate captured by the separation section 14. Similarly, the time required to discharge the hardness component in the reclaimed water replacement flow path 30b can be set based on the actual design, which is the time required to completely discharge the water from the inlet 2 through the bypass flow path 29 to the drain outlet 16.

[0225] In the water softening device 1b, when the regeneration process is completed, the operation of electrode 13 and water pump 19 is stopped. It should be noted that the end of the regeneration process is defined as a constant time (e.g., 2 hours) elapsed from the start of the regeneration process, excluding the time required for hardness component removal and valve switching. Alternatively, multiple hardness component removal processes may be performed during the regeneration process (until its completion). When the regeneration process is completed, the process transitions to water softening.

[0226] (Water softening treatment)

[0227] Regarding the water softening treatment, the content is the same as that described in Implementation Method 1, so detailed descriptions are omitted.

[0228] As described above, in the water softening device 1b, regeneration treatment, hardness component discharge treatment, and water softening treatment are repeatedly performed.

[0229] In addition to the effects (1) to (3) obtained from Embodiment 1, the water softening device 1b according to Embodiment 3 can also enjoy the following effects.

[0230] (5) In the water softening device 1b, it is possible to perform acid separation cleaning treatment that discharges hardness components from the separation section 14 and the water softening tank 3, and reclaimed water replacement treatment that discharges hardness components from the neutralization tank 4, the water storage tank 15, the water pump 19, and the electrolysis tank 12, in parallel, and hardness component discharge treatment.

[0231] Therefore, while cleaning the separation section 14, the regenerated water in the flow path can be discharged to the softening device 1b. As a result, the amount of hardness components in the precipitates and the regenerated water in the regeneration process can be reduced in a short time, thus enabling smooth regeneration of the ion exchange resin and further shortening the regeneration time required for the softening device 1b.

[0232] The present invention has been described above based on embodiments. These embodiments are illustrative, and those skilled in the art will understand that various modifications can be made to the combination of the above-described constituent elements or processing techniques, and such modifications are also within the scope of the present invention.

[0233] In the water softening apparatuses (1, 1a, 1b) of the above embodiments, a water storage tank 15 is provided to mix acidic electrolyzed water and alkaline electrolyzed water, but this is not a limitation. For example, the flow paths may be separated in a manner where the acidic and alkaline electrolyzed water are not mixed. In this case, a water storage tank may be provided for each flow path. In this way, the amount of water during regeneration can be ensured in each flow path.

[0234] In the water softening apparatuses (1, 1a, 1b) of the above embodiments, there is a structure comprising one water softening tank 3 and one neutralization tank 4, but it is not limited to this. For example, it is also possible to have two water softening tanks and two neutralization tanks respectively, and to pass water through the first water softening tank, the first neutralization tank, the second water softening tank, and the second neutralization tank in that order during the water softening process. In this way, water softening and neutralization can be performed alternately during the water softening process, thereby improving the water softening performance.

[0235] In the water softening apparatuses (1, 1a, 1b) of the above embodiments, a water pump 19 is provided to mix acidic and alkaline electrolyzed water and deliver it to the electrolysis cell 12, but this is not a limitation. For example, the flow path can be set up so that the acidic and alkaline electrolyzed water do not mix, and each flow path can be used for delivery. In this case, in order to suppress the mixing of acidic and alkaline electrolyzed water in the electrolysis cell 12, a partition wall that allows ions to pass through is provided in the electrolysis cell 12. As a specific water delivery method, in the flow path for the flow of acidic electrolyzed water, the acidic electrolyzed water delivered from the acidic electrolyzed water side outlet of the electrolysis cell 12 flows through the water softening tank 3 and the water pump, and flows into the electrolysis cell 12 from the acidic electrolyzed water side inlet provided in the electrolysis cell 12. Furthermore, in the flow path supplying alkaline electrolyzed water, the alkaline electrolyzed water supplied from the alkaline electrolyzed water side outlet of the electrolyzer 12 flows through the separation section 14, the neutralization tank 4, and the water pump, and flows into the electrolyzer 12 from the alkaline electrolyzed water side inlet provided in the electrolyzer 12. In this case, by installing a water pump in each flow path, the flow rate during regeneration can be detected and controlled using the current value of the water pump in each flow path. In this way, regeneration treatment and hardness component removal treatment can also be performed in accordance with the current value of the water pump.

[0236] In the water softening apparatuses (1, 1a, 1b) of the above embodiments, the control unit 17 includes a current value detection unit 18, but is not limited to this. For example, the current value detection unit 18 may be provided at the water pump 19, or at a location other than the control unit 17 and the water pump 19. In either case, the current value detection unit 18 can be provided in a manner that detects the current value of the water pump 19 and the control unit 17 can control the operation state of the water softening apparatus 1 based on the detected current value. In this way, regeneration processing and hardness component removal processing can be performed in accordance with the current value of the water pump 19.

[0237] Industrial applicability

[0238] The water softening device of the present invention can be applied to point-of-use (POU) or point-of-entry (POE) water purification devices, etc.

[0239] Explanation of reference numerals in the attached figures

[0240] 1: Water softening device, 1a: Water softening device, 1b: Water softening device, 2: Inlet, 3: Water softening tank, 4: Neutralization tank, 5: Water inlet, 6: Regeneration 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: Electrode, 13a: Electrode, 13b: Electrode, 14: Separation section, 15: Water storage tank, 16: Drain outlet, 17: Control section, 18: Current detection section, 19: Water pump, 20: Circulation flow path, 20a: First circulation flow path, 20b: Second circulation flow path, 21: First supply flow path, 22: The... 1. Recycling flow path; 23. Second supply flow path; 24. Second recycling flow path; 25. Water delivery flow path; 26. Drainage flow path; 27. Raw water separation section cleaning flow path; 27a. Acid separation section cleaning flow path; 27b. Acid separation section cleaning flow path; 29. ​​Bypass flow path; 30. Reclaimed water replacement flow path; 30a. Reclaimed water replacement flow path; 30b. Reclaimed water replacement flow path; 31. On / off valve; 32. On / off valve; 33. On / off valve; 34. On / off valve; 35. On / off valve; 36. On / off valve; 37. On / off valve; 38. On / off valve; 39. On / off valve; 42. On / off valve; 43. On / off valve; 44. On / off valve; 45. On / off valve.

Claims

1. A water softening device, wherein, The water softening device includes: A water softening tank uses a weakly acidic cation exchange resin to soften raw water containing hardness components to produce soft water. Neutralization tank, which uses a weakly basic anion exchange resin to neutralize the pH of the soft water generated from the softening tank; An electrolyzer that generates acidic electrolyzed water by regenerating the weakly acidic cation exchange resin in the softening tank and alkaline electrolyzed water by regenerating the weakly basic anion exchange resin in the neutralization tank. A water pump, which is installed in the flow path on the upstream side of the electrolytic cell, delivers the alkaline electrolyzed water to the neutralization tank; A current detection unit detects the current value of the water pump. The control unit controls the regeneration process based on the current value detected by the current value detection unit. The regeneration process performs at least one of the regeneration of the weakly acidic cation exchange resin using the acidic electrolyzed water and the regeneration of the weakly basic anion exchange resin using the alkaline electrolyzed water. as well as A separation section is provided in the flow path connecting the electrolytic cell and the neutralization tank, and separates the precipitates caused by the hardness components contained in the alkaline electrolyzed water introduced into the electrolytic cell. During the regeneration process, the control unit... If the current value of the water pump detected by the current value detection unit is above a predetermined value, the regeneration process continues. If the current value of the water pump detected by the current value detection unit is less than the predetermined value, the regeneration process is stopped, and the process is switched to the discharge process of the hardness component inside the device to the outside of the device. The control unit performs a raw water separation process relative to the separation unit, causing the raw water to flow in from the downstream side of the separation unit, in order to discharge the hardness component.

2. The water softening device according to claim 1, wherein, The control unit performs an acid separation process, in which raw water is introduced into the softening tank to generate acidic soft water, and the acidic soft water flows into the separation unit from the downstream side of the separation unit, as a discharge process for the hardness component.

3. The water softening device according to claim 1, wherein, The control unit performs a regenerated water replacement process, in which the water in the circulation path formed during the regeneration process is replaced with the original water, and the regenerated water is discharged as the hardness component.

4. The water softening device according to claim 1, wherein, After the raw water separation unit is cleaned, the control unit is transferred to a regenerated water replacement process, in which the water in the circulation path formed during the regeneration process is replaced with the raw water.

5. The water softening device according to claim 2, wherein, After the acid separation unit is cleaned, the control unit is transferred to a regenerated water replacement process, in which the water in the circulation path formed during the regeneration process is replaced with the original water.

6. The water softening device according to claim 2, wherein, The control unit performs the acid separation unit cleaning process and the regenerated water replacement process, which replaces the water in the circulation path formed during the regeneration process with the original water, as a discharge process for the hardness component.

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