Softening device

Abstract

To provide a water softening apparatus capable of suppressing extending a time required for regeneration processing of an ion exchange resin of the water softening apparatus.SOLUTION: A water softening apparatus 1 comprises a water softening tank 3, a neutralization tank 4, an electrolytic tank 12, and a separation part 14. The water softening tank 3 converts raw water including hard components to soften water by using a weakly acidic cation-exchange resin 10. The neutralization tank 4 neutralizes pH of soft water passed through the water softening tank by using a weakly basic anion-exchange resin 11. The electrolytic tank 12 generates acidic electrolytic water for regeneration of the weakly acidic cation-exchange resin 10 of the water softening tank 3 and alkaline electrolytic water for regeneration of the weakly basic anion-exchange resin 11 of the neutralization tank 4. The water softening apparatus 1 performs exchange processing of water conduction of raw water to the water softening tank 3 during regeneration processing of the water softening tank 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In conventional water softeners using weakly acidic cation exchange resins, a known method of regenerating the cation exchange resin without using salt is to regenerate the cation exchange resin using acidic electrolyzed water (see, for example, Patent Document 1). The weakly acidic cation exchange resin has a proton at the end of its functional group, and softens the raw water by exchanging hardness components (e.g., calcium ions, magnesium ions) in the raw water for hydrogen ions. The raw water softened by the weakly acidic cation exchange resin contains hydrogen ions and is acidic. The hydrogen ions in the softened water are adsorbed by a weakly basic anion exchange resin provided downstream of the weakly acidic cation exchange resin, thereby neutralizing the softened raw water. In conventional water softeners, a known method of regenerating the weakly basic anion exchange resin is to regenerate the weakly basic anion exchange resin using alkaline electrolyzed water (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-30973 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-142674 Summary of the Invention [Problem to be solved by the invention]

[0004] In such conventional water softeners, as the regeneration process of the weakly acidic cation exchange resin and the weakly basic anion exchange resin progresses, the hardness of the acidic electrolyzed water increases due to hardness components (e.g., calcium ions and magnesium ions) released from the water softening tank. Therefore, in a system in which acidic electrolyzed water with increased hardness is re-electrolyzed and reused for regeneration, the hardness of the acidic electrolyzed water increases as time passes from the start of the regeneration process. Therefore, in such a system, as the hardness of the acidic electrolyzed water increases, it becomes difficult for the weakly acidic cation exchange resin to release hardness components, resulting in a problem of extending the regeneration time of the water softening tank.

[0005] SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has as its object to provide a water softening device that can shorten the time required for regenerating the ion exchange resin of the water softening device. [Means for solving the problem]

[0006] To achieve this object, the water softening device according to the present invention comprises a water softening tank, a neutralization tank, an electrolytic tank, A separation unit; The water softening tank softens raw water containing hardness components using a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water that has passed through the water softening tank using a weakly basic anion exchange resin. The electrolytic tank generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening tank and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization tank. The separation section is provided in a flow path that connects the electrolytic cell and the neutralization cell, and separates precipitates resulting from hardness components contained in the water introduced into the electrolytic cell. The water softener performs a replacement process in which raw water is passed through the water softening tank during the regeneration process of the water softening tank. In addition, in the replacement process, the raw water that has passed through the water softening tank is passed through the separation section without passing through the neutralization tank. This will achieve the intended purpose. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a water softening device that can shorten the time required for regenerating the ion exchange resin of the water softening device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a water softening device according to the first embodiment. [Figure 2] FIG. 2 is a configuration diagram showing a circulation flow path of the water softening device according to the first embodiment. [Figure 3] FIG. 3 is a configuration diagram showing the replacement flow path of the water softening device according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing the operating state of the water softening device according to the first embodiment. [Figure 5] FIG. 5 is a conceptual diagram showing the configuration of a water softening device according to the second embodiment. [Figure 6] FIG. 6 is a configuration diagram showing a circulation flow path of a water softening device according to the second embodiment. [Figure 7] FIG. 7 is a configuration diagram showing a replacement flow path of a water softening device according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing the state of the water softening device according to the second embodiment during operation. [Figure 9] FIG. 9 is a conceptual diagram showing the configuration of a water softening device according to the third embodiment. [Figure 10] FIG. 10 is a conceptual diagram showing the configuration of a water softening device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The water softening apparatus according to the present invention comprises a water softening tank, a neutralization tank, and an electrolytic tank. The water softening tank softens raw water containing hardness components and chloride ions using a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water that has passed through the water softening tank using a weakly basic anion exchange resin. The electrolytic tank generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening tank, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization tank. The water softening apparatus then performs a water replacement process by passing raw water through the water softening tank during the regeneration process of the water softening tank.

[0010] With this configuration, the water in the water softening tank can be replaced with raw water from the acidic electrolyzed water containing a large amount of hardness components released from the weakly acidic cation exchange resin during the regeneration process. This reduces the amount of hardness components in the regeneration process path, making it possible to provide a water softening device that can prevent the time required for the regeneration process of the ion exchange resin in the water softening device from becoming too long.

[0011] The water softening apparatus according to the present invention further includes a separation unit. The separation unit is provided in a flow path connecting the electrolytic cell and the neutralization cell, and separates precipitates resulting from hardness components contained in water introduced into the electrolytic cell. In the replacement process, raw water that has flowed through the water softening cell is passed through the separation unit. This allows the separation unit to be cleaned using the acidic soft water that has flowed through the water softening cell, and precipitates containing hardness components that have precipitated in the separation unit to be dissolved. Therefore, the pressure loss in the separation unit can be reduced, a sufficient amount of alkaline electrolyzed water can be supplied to the neutralization cell, and the water softening apparatus can smoothly perform the regeneration process.

[0012] In the water softening apparatus according to the present invention, raw water that has passed through the water softening tank may be introduced into the separation unit from the downstream side of the separation unit during the replacement process. This allows backwashing of the separation unit. This improves the efficiency of the replacement process and allows the replacement process to be completed in a shorter period of time.

[0013] The water softening device according to the present invention may further include a flow rate detector that detects the flow rate of water flowing through the separation unit, and may start the replacement process when the flow rate detected by the flow rate detector falls below a predetermined value. This allows the flow rate of water flowing through the separation unit to be grasped, and the start of the replacement process to be determined based on the flow rate information. This allows the replacement process to be started at a more effective timing.

[0014] Furthermore, the water softening device according to the present invention may include a static pressure detection unit that detects the static pressure of the flowing water before the separation unit, and may perform a replacement process when the static pressure detected by the static pressure detection unit exceeds a predetermined value. This allows the static pressure state of the separation unit during the regeneration process to be grasped, and the start of the replacement process to be determined based on the static pressure detection information. This allows the replacement process to be started at a more effective timing.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are examples of specific embodiments of the present invention and do not limit the technical scope of the present invention. Furthermore, each drawing used in the embodiments is a schematic drawing, and the ratios of the sizes and thicknesses of the components in each drawing do not necessarily reflect the actual dimensional ratios.

[0016] (Embodiment 1) A water softening device 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a conceptual diagram showing the configuration of the water softening device 1 according to the first embodiment of the present invention. Note that Fig. 1 conceptually shows each element of the water softening device 1.

[0017] (Overall composition) The water softening device 1 is a device that converts city water (raw water containing hardness components) supplied from the outside into neutral soft water that can be used as drinking water.

[0018] Specifically, as shown in Fig. 1, the water softening device 1 includes an inlet 2 for raw water from the outside, a water softening tank 3, a neutralization tank 4, an intake port 5 for treated softened water, and a regeneration device 6. The regeneration device 6 includes an electrolytic tank 12, a separation section 14, a water storage tank 15, and a water pump 19. The water softening device 1 also includes a drain outlet 16, a control section 17, a plurality of on-off valves (on-off valve 31, on-off valve 32, on-off valves 34 to 39, and on-off valve 41), and a selection valve 40.

[0019] The inlet 2 is connected to city water and is an opening for introducing city water into the water softening device 1.

[0020] The water intake 5 is an opening that flows through the water softening device 1 and supplies the softened water to the outside of the device. The water softening device 1 is capable of extracting softened water from the water intake 5 using the pressure of city water.

[0021] The inlet 2 is connected to the water intake 5 by flow paths 7, 8, and 9. Flow path 7 is a flow path that connects the inlet 2 to the water softening tank 3. Flow path 8 is a flow path that connects the water softening tank 3 to the neutralization tank 4. Flow path 9 is a flow path that connects the neutralization tank 4 to the water intake 5.

[0022] In other words, flow path 7 is a flow path that guides raw water containing hardness components from inlet 2 to water softening tank 3. Furthermore, flow path 8 is a flow path that guides raw water softened in water softening tank 3 to neutralization tank 4. Flow path 9 is a flow path that guides softened water neutralized in neutralization tank 4 to water intake 5.

[0023] In other words, in the water softening process in the water softening device 1, city water supplied from outside flows through the inlet 2, flow path 7, water softening tank 3, flow path 8, neutralization tank 4, flow path 9, and water intake 5 in that order, and is discharged as neutral soft water.

[0024] (Water softening tank and neutralization tank) The water softening tank 3 is filled with a weakly acidic cation exchange resin 10, and the neutralization tank 4 is filled with a weakly basic anion exchange resin 11.

[0025] Here, there are no particular limitations on the weakly acidic cation exchange resin 10, and a general-purpose one can be used, such as one that uses a carboxyl group (-COOH) as the exchange group. Furthermore, the hydrogen ion (H+), which is the counter ion of the carboxyl group, may be replaced with a cation such as a metal ion or an ammonium ion (NH4+).

[0026] The weakly basic anion exchange resin 11 is not particularly limited, and any general-purpose resin can be used, such as a free base type resin.

[0027] The water softening tank 3 softens raw water containing hardness components through the action of weakly acidic cation exchange resins 10. More specifically, the water softening tank 3 is equipped with weakly acidic cation exchange resins 10 having hydrogen ions at the ends of their functional groups. The water softening tank 3 exchanges cations (calcium ions, magnesium ions), which are hardness components contained in the flowing water (raw water), with hydrogen ions. This reduces the hardness of the raw water introduced into the water softening tank 3, thereby softening the raw water. Furthermore, because the ends of the functional groups of the weakly acidic cation exchange resins 10 are hydrogen ions, the weakly acidic cation exchange resins 10 can be regenerated using acidic electrolyzed water in the regeneration process described below. During this process, the cations, which are hardness components, that were captured during the water softening process are released from the weakly acidic cation exchange resins 10.

[0028] Raw water containing hardness components is passed through the water softening tank 3 via flow path 7, and as it passes through the weakly acidic cation exchange resin 10 filled inside, the raw water containing hardness components is softened and passed through flow path 8 to the neutralization tank 4. However, the softened water treated with the weakly acidic cation exchange resin 10 contains many hydrogen ions that have been exchanged for hardness components. In other words, the softened water flowing out of the water softening tank 3 is acidic soft water (acidic soft water) that contains many hydrogen ions.

[0029] The neutralization tank 4 neutralizes the pH of the softened water (acidified softened water) containing hydrogen ions coming out of the water softening tank 3 by the action of the weakly basic anion exchange resin 11, converting it into neutral water (neutral soft water). More specifically, the neutralization tank 4 is equipped with the weakly basic anion exchange resin 11, which adsorbs the hydrogen ions contained in the softened water from the water softening tank 3 together with anions (negative ions), thereby increasing the pH of the softened water and making it neutral soft water. Furthermore, the weakly basic anion exchange resin 11 can be regenerated using alkaline electrolyzed water in the regeneration process described below.

[0030] Softened water containing hydrogen ions is passed through the neutralization tank 4 from the flow path 8, and passes through the weakly basic anion exchange resin 11 filled inside, thereby neutralizing the acidified softened water coming out of the water softening tank 3, and the neutral softened water is passed to the outside through the flow path 9.

[0031] (playback device) The regeneration device 6 is a device that regenerates the weakly acidic cation exchange resin 10 in the water softening tank 3 and the weakly basic anion exchange resin 11 in the neutralization tank 4. Specifically, as described above, the regeneration device 6 includes the electrolytic tank 12, the separation section 14, the water storage tank 15, and the water pump 19. In the regeneration device 6, a first supply flow path 21, a first recovery flow path 22, a flow path 29, a second supply flow path 23, and a second recovery flow path 24 are connected to the flow paths 7, 8, and 9 from the inlet 2 to the water intake 5, respectively. Note that the flow path 8 is connected to each of the flow paths in the following order from the upstream side: the first recovery flow path 22, the flow path 29, and the second supply flow path 23. The first supply flow path 21, the first recovery flow path 22, the flow path 29, the second supply flow path 23, and the second recovery flow path 24 constitute a circulation flow path 20 (first circulation flow path 20a, second circulation flow path 20b) or a replacement flow path 27, which will be described later.

[0032] Here, the first supply flow path 21 is a flow path that supplies acidic electrolyzed water from the electrolytic cell 12 to the water softening cell 3. The first recovery flow path 22 is a flow path that recovers water containing hardness components that has passed through the water softening cell 3 to the water storage cell 15. The second supply flow path 23 is a flow path that supplies alkaline electrolyzed water from the electrolytic cell 12 to the neutralization cell 4. The second recovery flow path 24 is a flow path that recovers water that has passed through the neutralization cell 4 to the water storage cell 15. The flow path 29 is a flow path that supplies acidic soft water discharged from the water softening cell 3 to the separation unit 14.

[0033] (electrolytic cell) The electrolytic cell 12 generates and discharges acidic electrolyzed water and alkaline electrolyzed water by electrolyzing the input water (water supplied from the water tank 15) using a pair of electrodes 13 (electrode 13a and electrode 13b) installed inside. More specifically, hydrogen ions are generated by electrolysis at the electrode 13a, which serves as an anode during electrolysis, to generate acidic electrolyzed water. Meanwhile, hydroxide ions are generated by electrolysis at the electrode 13b, which serves as a cathode during electrolysis, to generate alkaline electrolyzed water. The electrolytic cell 12 supplies the acidic electrolyzed water to the water softening cell 3 via the first supply flow path 21, and supplies the alkaline electrolyzed water to the neutralization cell 4 via the second supply flow path 23. As will be described in detail later, the acidic electrolyzed water generated by the electrolytic cell 12 is used to regenerate the weakly acidic cation exchange resin 10 in the water softening cell 3, and the alkaline electrolyzed water generated by the electrolytic cell 12 is used to regenerate the weakly basic anion exchange resin 11 in the neutralization cell 4. The electrolytic cell 12 is configured so that the state of current flow to the pair of electrodes 13 can be controlled by a control unit 17, which will be described later.

[0034] (Water tank) The water tank 15 secures and stores water to be circulated through the circulation flow path 20 (see FIG. 2) when regenerating the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11. The water tank 15 also mixes the acidic electrolyzed water containing hardness components that has been circulated through the water softening tank 3 with the alkaline electrolyzed water containing anions that has been circulated through the neutralization tank 4, and supplies the mixed water to the electrolytic tank 12.

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

[0036] (Water pump) The water pump 19 is a device that circulates water through the circulation flow path 20 (see FIG. 2) during the regeneration treatment by the regeneration device 6. The water pump 19 is provided in a water flow path 25 that communicates between the water storage tank 15 and the electrolytic cell 12. The water pump 19 is preferably arranged upstream of the electrolytic cell 12 and downstream of the water storage tank 15. This arrangement is because it makes it easier to circulate water through the first circulation flow path 20a and the second circulation flow path 20b with a single water pump 19. The water pump 19 is also connected to the control unit 17, which will be described later, wirelessly or via a wired connection so as to be able to communicate with it.

[0037] (separation part) The separation unit 14 is provided in the second supply flow path 23 that connects the electrolytic cell 12 and the neutralization cell 4. The separation unit 14 separates precipitates contained in the alkaline electrolyzed water delivered from the electrolytic cell 12. The precipitates are reaction products generated in the electrolytic cell 12 when the alkaline electrolyzed water reacts with the cations of hardness components released from the water softener cell 3 during the regeneration process of the water softener cell 3. More specifically, while water is being electrolyzed in the electrolytic cell 12, hardness components (e.g., calcium ions, magnesium ions) released from the water softener cell 3 during the regeneration process move to the cathode (electrode 13b). Since alkaline electrolyzed water is produced on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates. For example, when the hardness component is calcium ion, mixing with alkaline electrolyzed water may result in a reaction to produce calcium carbonate or calcium hydroxide. The precipitates derived from hardness components are separated as precipitates in the separation unit 14 provided in the second supply flow path 23. Separating the precipitates derived from hardness components in the separation unit 14 can prevent the precipitates from flowing into the neutralization tank 4 and accumulating therein. Therefore, when restarting the water softening process after the completion of the regeneration process, the precipitates accumulated in the neutralization tank 4 react with the hydrogen ions released from the water softening tank 3 to form hardness components, which can prevent an increase in the hardness of the softened water delivered from the neutralization tank 4. During the regeneration process, the alkaline electrolyzed water from which the precipitates derived from hardness components have been separated in the separation unit 14 flows through the neutralization tank 4, is mixed with the acidic electrolyzed water, and is electrolyzed again in the electrolytic tank 12 to produce acidic electrolyzed water and alkaline electrolyzed water, which are used to regenerate the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11, respectively. At this time, the acidic electrolyzed water contains fewer hardness components than city water or water without the separation unit 14. In other words, by separating the precipitate in the separation section 14, the hardness of the acidic electrolyzed water is reduced, so that the amount of hardness components flowing into the water softening tank 3 can be reduced, and the decrease in the regeneration efficiency of the weakly acidic cation exchange resin 10 can be suppressed.

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

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

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

[0041] Thread-wound filters accommodate particle sizes ranging from 1 to 150 micrometers and are primarily used as prefilters. Pleated filters and membrane filters are available for a wide range of particle sizes, from approximately 0.03 to 100 micrometers. In particular, in implementing the present invention, filters with a precision of approximately 0.5 to 1.5 micrometers are preferred for capturing hardness components that precipitate during the regeneration process described below. Because alkaline electrolyzed water flows through the separation unit 14 during the regeneration process described below and acidic electrolyzed water flows through the separation unit 14 during the cleaning process, a material with high corrosion resistance to acids and alkalis (e.g., polypropylene) is preferred for the cartridge-type filter.

[0042] The granular filter media used in the filtration layer are designed to capture and remove hardness components. However, depending on the presence of particles with a surface potential that attracts them and the presence of ions in the raw water, particles with a particle diameter of approximately 1 to 10 micrometers or color can also be removed. Granular filter media can be filter sand, pellet-shaped fiber filter media, or any other filter material suitable for the target substance. Granular filter media can be made of any material that settles in water and has a hardness that makes it resistant to deformation under pressure, such as sand, anthracite, garnet, ceramics, granular activated carbon, iron oxyhydroxide, or manganese sand. Particle diameters of 0.3 to 5.0 millimeters and a uniformity coefficient of 1.2 to 2.0 are recommended.

[0043] Multilayer filtration, which uses a mixture of filter media with different specific gravities, involves stacking different particle sizes from the bottom up as layers for filtration. Multilayer filtration typically involves mixing small particles with high specific gravity and large particles with low specific gravity to create a multilayer structure. Compared to using a single type of filter media, multilayer filtration offers advantages such as higher filtration efficiency per unit volume and lower head loss. Granular filter media, for example, can be used by mixing 0.3 mm garnet, 0.6 mm sand, and 1.0 mm anthracite in a 2:1:1 ratio. It is preferable to adjust the mixing ratio or particle size depending on the particle characteristics of the suspended solids.

[0044] (Shut-off valve and selection valve) A plurality of on-off valves (on-off valve 31, on-off valve 32, on-off valves 34 to 39, and on-off valve 41) are provided in each flow path, respectively, and switch each flow path between an "open" state and a "closed" state.

[0045] The selection valve 40 is provided between the separation section 14 and the neutralization tank 4. The selection valve 40 is also provided at the confluence of the second supply flow path 23 and the drainage flow path 26, and determines the flow direction of the acidic soft water and alkaline electrolyzed water that have flowed through the separation section 14. Specifically, the selection valve 40 switches between a flow state in which the alkaline electrolyzed water that has flowed through the separation section 14 reaches the neutralization tank 4 during the regeneration process, and a flow state in which the water that has flowed out of the separation section 14 reaches the drain outlet 16 during the replacement process.

[0046] Furthermore, the multiple on-off valves (on-off valve 31, on-off valve 32, on-off valves 34 to 39, and on-off valve 41) and the selection valve 40 are each connected to a control unit 17 (described later) wirelessly or by wire so as to be able to communicate with each other.

[0047] (Drain port) The drain outlet 16 discharges the acidic soft water that has flowed through the separation section 14 to the outside of the apparatus when the separation section 14 is cleaned (replaced) as described below.

[0048] More specifically, during replacement processing, the drain outlet 16 discharges water that has flowed through the flow path 7, the water softening tank 3, the flow path 8, the flow path 29, the on-off valve 41, the separation section 14, the selection valve 40, and the drain flow path 26, and which contains hardness components produced by the dissolution of precipitates in the separation section 14, out of the device.

[0049] (Control unit) The control unit 17 controls the regeneration process of the weakly acidic cation exchange resin 10 in the water softening tank 3 and the weakly basic anion exchange resin 11 in the neutralization tank 4. The control unit 17 also controls the replacement process of passing raw water through the water softening tank 3. The control unit 17 also controls the water softening process of softening raw water containing hardness components. The control unit 17 also controls the operation of the on-off valve 41 to control the flow direction and flow rate of the acidic softened water flowing out of the water softening tank 3. The control unit 17 also controls the operation of the selection valve 40 to control the flow direction of the water flowing out of the separation unit 14. The control unit 17 also controls the switching between the regeneration process, replacement process, and water softening process of the water softening device 1. At this time, the control unit 17 controls the operation of the electrode 13, the water pump 19, the multiple on-off valves (on-off valve 31, on-off valve 32, on-off valves 34 to 39, and on-off valve 41), and the selection valve 40, and switches between the regeneration process, replacement process, and water softening process and executes each process.

[0050] (flow path) Next, the circulation flow path 20 formed during the regeneration treatment of the water softening device 1 will be described with reference to Fig. 2. Fig. 2 is a configuration diagram showing the circulation flow path 20 of the water softening device 1.

[0051] Although the explanation may be redundant, as shown in Fig. 2, in the water softening apparatus 1, the electrolytic cell 12 and the water tank 15 that constitute the regeneration device 6 are connected in communication with each other via a water supply flow path 25. Furthermore, the electrolytic cell 12 and the water tank 15 are connected in communication with the flow paths 7, 8, and 9 that run from the inlet 2 to the water intake 5 via 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 regeneration device 6, a circulation flow path 20 is formed by combining these flow paths.

[0052] The first supply flow path 21 is a flow path that supplies acidic electrolyzed water from the electrolytic cell 12 to the water softening cell 3, and is provided with an on-off valve 35. That is, the water softening device 1 is provided with the first supply flow path 21 that allows acidic electrolyzed water to be drawn from the electrolytic cell 12 and sent to the upstream side of the water softening cell 3.

[0053] 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 into the water storage tank 15, and an on-off valve 36 is installed in this flow path. In other words, the water softening device 1 is provided with the first recovery flow path 22 that enables the upstream side of the water storage tank 15 to be connected to the downstream side of the water softening tank 3.

[0054] The second supply flow path 23 is a flow path for supplying alkaline electrolyzed water from the electrolytic cell 12 to the neutralization cell 4 via the separation unit 14 during the regeneration process described below, and is equipped with the separation unit 14, a selection valve 40, and an on-off valve 37. That is, the water softener 1 is provided with the second supply flow path 23, which separates precipitates derived from hardness components contained in the alkaline electrolyzed water drawn from the electrolytic cell 12 using the separation unit 14, and allows the alkaline electrolyzed water from which the precipitates have been separated to be sent upstream of the neutralization cell 4. The second supply flow path 23 is connected to the flow path 8 downstream of the first recovery flow path 22 and the flow path 29. This is to prevent mixing of the acidic electrolyzed water discharged from the water softening cell 3 and the alkaline electrolyzed water delivered from the electrolytic cell 12 during the regeneration process described below. That is, the flow path 8 is connected to the first recovery flow path 22, the flow path 29, and the second supply flow path 23, in this order from the upstream side.

[0055] The second recovery flow path 24 is a flow path that recovers the water that has passed through the neutralization tank 4 into the water storage tank 15, and an on-off valve 38 is installed in this flow path. In other words, the water softening device 1 is equipped with the second recovery flow path 24 that enables the upstream side of the water storage tank 15 to be connected to the downstream side of the neutralization tank 4.

[0056] The circulation flow path 20 includes a first circulation flow path 20a through which water pumped from the water storage tank 15 by the water supply pump 19 flows through the water softening tank 3, and a second circulation flow path 20b through which water pumped from the water storage tank 15 by the water supply pump 19 flows through the neutralization tank 4.

[0057] 2 (white arrow), first circulation flow path 20a is a flow path through which water sent out from water tank 15 by water pump 19 flows through electrolytic cell 12 and water softening tank 3, and returns to water tank 15 for circulation. More specifically, first circulation flow path 20a is a flow path through which water sent out from water tank 15 by water pump 19 flows and circulates through water supply flow path 25, electrolytic cell 12, first supply flow path 21, on-off valve 35, water softening tank 3, first recovery flow path 22, on-off valve 36, and water tank 15 in this order.

[0058] 2 (black arrow), second circulation flow path 20b is a flow path through which water sent from water tank 15 by water supply pump 19 flows through electrolytic cell 12 and neutralization cell 4, and returns to water tank 15 for circulation. More specifically, second circulation flow path 20b is a flow path through which water sent from water tank 15 by water supply pump 19 flows and circulates through water supply flow path 25, electrolytic cell 12, second supply flow path 23, separation unit 14, selection valve 40, on-off valve 37, neutralization cell 4, second recovery flow path 24, on-off valve 38, and water tank 15 in this order.

[0059] Here, in order to circulate water in the circulation flow path 20, an on-off valve 31 is installed in the flow path 7 downstream of the inlet 2. By closing the on-off valve 31 and opening the on-off valve 35, the first supply flow path 21 is connected to the upstream side of the water softening tank 3. This allows acidic electrolyzed water from the electrolytic tank 12 to be supplied to the water softening tank 3.

[0060] In addition, an on-off valve 32 is installed in the flow path 8 downstream of the first recovery flow path 22 and the flow path 29 and upstream of the second supply flow path 23. By closing the on-off valve 32 and the on-off valve 41 installed in the flow path 29 and opening the on-off valve 36, the first recovery flow path 22 is connected to the downstream side of the water softening tank 3. This allows the water softening device 1 to recover the water (acidic electrolyzed water containing hardness components) that has flowed through the water softening tank 3 into the water storage tank 15.

[0061] Furthermore, by closing the on-off valves 32 and 41, opening the on-off valve 37, and switching the flow direction of the selection valve 40 to the direction of the neutralization tank 4 (the direction from the separation section 14 to the neutralization tank 4), the second supply flow path 23 is connected in communication with the upstream side of the neutralization tank 4. As a result, in the water softening device 1, alkaline electrolyzed water from the electrolytic tank 12 can be circulated through the separation section 14 and supplied to the neutralization tank 4.

[0062] In addition, an on-off valve 34 is installed in the flow path 9 downstream of the neutralization tank 4. By closing the on-off valve 34 and opening the on-off valve 38, the second recovery flow path 24 is connected to the downstream side of the neutralization tank 4. This makes it possible to recover the water (alkaline electrolyzed water containing anions) that has passed through the second recovery flow path 24 into the water tank 15.

[0063] In addition, by closing the on-off valve 34, the circulation of water to the circulation flow path 20 can be started, while by opening the on-off valve 34, the circulation of water to the circulation flow path 20 can be stopped.

[0064] In addition, an on-off valve 39 is installed in the water supply flow path 25 downstream of the water tank 15 (at a position between the water tank 15 and the water supply pump 19). By closing the on-off valve 39, water can be stored in the water tank 15. On the other hand, by opening the on-off valve 39, water can be supplied to the water supply flow path 25.

[0065] Furthermore, a selection valve 40 is installed in the second supply flow path 23 between the separation unit 14 and the neutralization tank 4. By switching the selection valve 40, it is possible to switch between a flow path state in which alkaline electrolyzed water generated by electrolysis at the electrode 13b flows through the second supply flow path 23 and the separation unit 14 to reach the neutralization tank 4, and a flow path state in which the water that has flowed through the separation unit 14 is discharged to the outside of the device through a drain outlet 16 via a drainage flow path 26 (described later). In the flow path state in which the water that has flowed through the separation unit 14 is discharged to the outside of the device through the drain outlet 16, the acidic soft water used for cleaning the separation unit 14 during the replacement process is discharged.

[0066] Next, the replacement flow path 27 formed during the replacement process of the water softening device 1 will be described with reference to Fig. 3. Fig. 3 is a configuration diagram showing the replacement flow path 27 of the water softening device 1.

[0067] As shown in Figure 3, the replacement flow path 27 is made up of flow paths connecting the inlet 2, the water softening tank 3, the separation unit 14, and the drain outlet 16. The water softening tank 3 is connected in communication with the inlet 2 by flow path 7. The water softening tank 3 is also connected in communication with the separation unit 14 by flow path 8, flow path 29, and a second supply flow path 23. The separation unit 14 is connected in communication with the drain outlet 16 by the second supply flow path 23 and a drain flow path 26, which will be described later. A selection valve 40 is provided at the connection between the second supply flow path 23 and the drain flow path 26.

[0068] Flow path 29 is a flow path that supplies acidic softened water from the water softening tank 3 to the separation unit 14. Flow path 29 is connected in communication with flow path 8 between the water softening tank 3 and the second supply flow path 23. Flow path 29 is also connected in communication with the second supply flow path 23 between the electrolytic tank 12 and the separation unit 14. An on-off valve 41 is provided in flow path 29. In other words, the water softening device 1 is provided with flow path 29 that supplies acidic softened water softened in the water softening tank 3 to the separation unit 14 and is used to clean the separation unit 14.

[0069] The drainage flow path 26 is a flow path that discharges water from the selection valve 40 to the drain outlet 16. The drainage flow path 26 is connected in communication with the second supply flow path 23 between the separation section 14 and the neutralization tank 4. The selection valve 40 is provided in the drainage flow path 26. In other words, the water softening device 1 is equipped with the drainage flow path 26 that draws water from the selection valve 40 to the drain outlet 16 and enables the water to be discharged outside the device.

[0070] 3 (hatched arrow), replacement flow path 27 is a flow path through which water introduced from inlet 2 flows in this order through flow path 7 and water softening tank 3, and after being converted into acidic soft water in water softening tank 3, flows in this order through flow path 8, flow path 29, second supply flow path 23, and separation section 14, passes through selection valve 40 and drainage flow path 26, and is discharged outside the device from drain outlet 16. Replacement flow path 27 is used during a replacement process, which will be described later.

[0071] (Regeneration treatment, replacement treatment, wastewater treatment, and water softening treatment) Next, the regeneration process, replacement process, drainage process, and water softening process of the water softening device 1 starting from the regeneration process will be described with reference to Fig. 4. Fig. 4 is a diagram showing the state of the water softening device 1 during operation.

[0072] In the regeneration treatment, replacement treatment, wastewater treatment, and water softening treatment, the control unit 17 controls the on-off valve 31, on-off valve 32, on-off valves 34 to 39, selection valve 40, on-off valve 41, electrodes 13 of electrolytic cell 12, and water pump 19 to switch to the respective circulation states, as shown in FIG. 4 . The control unit 17 includes a computer system having a processor and a memory. The computer system functions as the control unit when the processor executes a program stored in the memory. Here, the program executed by the processor is pre-recorded in the memory of the computer system, but it may be recorded on a non-transitory recording medium such as a memory card and provided, or may be provided via a telecommunications line such as the Internet.

[0073] Here, "ON" in FIG. 4 indicates that the corresponding on-off valve is "open," that the electrode 13 is energized, and that the water pump 19 is operating. Blank spaces indicate that the corresponding on-off valve is "closed," that the electrode 13 is not energized, and that the water pump 19 is stopped. Also, the notation of the selection valve 40 in FIG. 4 indicates that the flow path is open to the component (neutralization tank 4 or drain port 16) corresponding to the number (symbol). Under normal conditions, the selection valve 40 is in a state where the flow path is open to the neutralization tank 4, but if it is not related to other processes, the space is left blank.

[0074] (Recycling) First, the operation of the regeneration device 6 of the water softening device 1 during regeneration treatment will be described in order with reference to the columns "Water injection" and "Regeneration" in FIG.

[0075] In the water softening apparatus 1, the water softening tank 3 filled with the weakly acidic cation exchange resin 10 loses or loses its cation exchange capacity with continued use. That is, once all of the hydrogen ions, which are the functional groups of the cation exchange resin, have been exchanged with calcium ions or magnesium ions, which are hardness components, the ion exchange becomes impossible. In this state, hardness components begin to be contained in the treated water. For this reason, in the water softening apparatus 1, it becomes necessary to regenerate the water softening tank 3 and the neutralization tank 4 using the regeneration device 6.

[0076] Therefore, in the water softening device 1, once per predetermined period (for example, one day (24 hours)), the control unit 17 identifies a time period during which the regeneration process is possible, and executes the regeneration process.

[0077] First, as shown in Fig. 4, when water is injected, the on-off valves 31 and 36 are opened. As a result, the water softening device 1 introduces raw water from the inlet 2 through the water softening tank 3 into the water storage tank 15 by the pressure of city water. At this time, the on-off valves 32, 34, 35, 37 to 39, and 41 are closed. In addition, the selection valve 40 connects the flow path in the direction in which the water that has flowed through the separation section 14 flows to the neutralization tank 4. By storing a predetermined amount of water in the water storage tank 15 according to the capacity of the water softening device 1, the regeneration device 6 can ensure the amount of water required for regeneration.

[0078] Next, during regeneration, when the on-off valves 31, 32, 34, and 41 are closed, the on-off valves 35 to 39 are opened, and the water flow direction of the selection valve 40 is set to the direction of the neutralization tank 4 (the direction from the separation section 14 to the neutralization tank 4), a first circulation flow path 20a and a second circulation flow path 20b are formed, as shown in Figure 2.

[0079] When the electrodes 13 of the electrolytic cell 12 and the water pump 19 are operated, the water stored in the water tank 15 circulates through the first circulation flow path 20a and the second circulation flow path 20b.

[0080] At this time, the acidic electrolyzed water produced in the electrolytic bath 12 is fed into the water softening bath 3 through the first supply flow path 21 and flows through the weakly acidic cation exchange resin 10 therein. That is, by flowing the acidic electrolyzed water through the weakly acidic cation exchange resin 10, the cations (hardness components) adsorbed on the weakly acidic cation exchange resin 10 undergo an ion exchange reaction with the hydrogen ions contained in the acidic electrolyzed water. This regenerates the weakly acidic cation exchange resin 10. After that, the acidic electrolyzed water that has flowed through the weakly acidic cation exchange resin 10 contains cations and flows into the first recovery flow path 22. That is, the acidic electrolyzed water that has flowed through the weakly acidic cation exchange resin 10 and contains cations is recovered into the water tank 15 via the first recovery flow path 22.

[0081] On the other hand, alkaline electrolyzed water produced in the electrolytic cell 12 is fed into the neutralization cell 4 through the second supply flow path 23 and the separation part 14, and flows through the weakly basic anion exchange resin 11 therein. That is, by passing alkaline electrolyzed water through the weakly basic anion exchange resin 11, anions adsorbed on the weakly basic anion exchange resin 11 undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water. This regenerates the weakly basic anion exchange resin 11. After that, the alkaline electrolyzed water that has passed through the weakly basic anion exchange resin 11 contains anions and flows into the second recovery flow path 24. That is, the alkaline electrolyzed water that has passed through the weakly basic anion exchange resin 11 and contains anions is recovered into the water tank 15 through the second recovery flow path 24.

[0082] In the water storage tank 15, the acidic electrolyzed water containing cations recovered from the water softening tank 3 and the alkaline electrolyzed water containing anions recovered from the neutralization tank 4 are mixed and neutralized.

[0083] At this time, by mixing acidic electrolyzed water containing cations (hardness components) with alkaline electrolyzed water containing anions, the hardness components react with hydroxide ions contained in the alkaline electrolyzed water, resulting in the formation of precipitates. However, at least in the initial stage of the regeneration process, the amount of hydroxide ions contained in the alkaline electrolyzed water flowing from the neutralization tank 4 is less than the amount of hardness components released from the water softening tank 3, making it difficult for precipitates to form. Therefore, the hardness components contained in the neutralized electrolyzed water are sent directly to the electrolysis tank 12.

[0084] Thereafter, the electrolyzed water mixed in the water storage tank 15 is passed through the water supply flow path 25 again to the electrolytic cell 12. The passed water is then electrolyzed again in the electrolytic cell 12.

[0085] As mentioned above, water is electrolyzed in the electrolytic cell 12, and a large amount of hydroxide ions are generated by electrolysis near the cathode, creating a state where precipitates are likely to form. That is, hardness components (e.g., calcium ions, magnesium ions) contained in the water supplied from the water storage tank 15 move to the cathode side and react with hydroxide ions to form precipitates. The alkaline electrolyzed water containing the precipitates is then sent to the second supply flow path 23 and flows into the separation unit 14.

[0086] In the separation unit 14, precipitates contained in the alkaline electrolyzed water are separated, and alkaline electrolyzed water (treated water) from which hardness components have been removed can be obtained. Then, the acidic electrolyzed water re-electrolyzed in the electrolytic cell 12 and the alkaline electrolyzed water re-electrolyzed in the electrolytic cell 12 and from which precipitates have been separated in the separation unit 14 are used to regenerate the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11, respectively.

[0087] Here, a problem with not providing the separation unit 14 is that during the regeneration process, hardness components released from the water softening tank react with alkaline electrolyzed water in the electrolytic tank, producing precipitates that flow into the neutralization tank and accumulate there. In other words, if the water softening process is resumed with the precipitates still accumulated in the neutralization tank, the precipitates will react with the hydrogen ions released from the water softening tank to form hardness components, resulting in a decrease in water softening performance. However, in this embodiment, the separation unit 14 separates the precipitates produced in the electrolytic tank 12, thereby preventing the accumulation of precipitates due to hardness components inside the neutralization tank 4. However, as the regeneration process progresses, the precipitates separated in the separation unit 14 gradually accumulate within the separation unit 14. This results in an increase in pressure loss in the separation unit 14. That is, in this embodiment, the water pump 19 provides a constant amount of energy to the circulation flow path 20, but as the pressure loss in the separation section 14 increases, the supply flow rate of alkaline electrolyzed water supplied to the neutralization tank 4 gradually decreases as the regeneration process progresses, which can make it difficult to complete the regeneration process of the neutralization tank 4.

[0088] Furthermore, as the regeneration process progresses, the concentration of hardness components in the acidic electrolyzed water containing hardness components recovered from the water softening tank 3 gradually increases. The weakly acidic cation exchange resin 10 has selectivity for the ions it adsorbs. When the concentrations of hydrogen ions and hardness components (calcium ions and magnesium ions) are similar, calcium ions or magnesium ions are more likely to be adsorbed. Therefore, when regenerating the weakly acidic cation exchange resin 10, it is necessary to increase the hydrogen ion concentration and supply hydrogen ions at a concentration relatively higher than the adsorbed calcium ions and magnesium ions. However, as the concentration of hardness components in the acidic electrolyzed water increases, the concentration of hydrogen ions decreases relative to the concentrations of calcium ions and magnesium ions. Therefore, it becomes difficult for the weakly acidic cation exchange resin 10 to release hardness components, and the amount of hardness components that can be recovered from the water softening tank 3 decreases, which slows down the progress of the regeneration process or may even prevent the regeneration process from being completed.

[0089] Therefore, in this embodiment, the regeneration process of the water softener 1 is temporarily stopped while the regeneration process is in progress (for example, two hours after the start of the regeneration process), and a replacement process is performed. That is, the operation of the electrode 13 and the water pump 19 is stopped, the on-off valves 35 to 39 are closed, and the on-off valves 31 and 41 are opened. Furthermore, the water flow direction of the selection valve 40 is switched from the direction toward the neutralization tank 4 (the direction from the separation unit 14 to the neutralization tank 4) to the direction toward the drain outlet 16 (the direction from the separation unit 14 to the drain outlet 16). This causes a transition from the regeneration process to the replacement process.

[0090] (Replacement process) The water softener 1 transitions to a replacement process when the regeneration process is temporarily stopped. The replacement process is a process in which the acidic electrolyzed water with a high concentration of hardness components remaining in the water softening tank 3 is discharged out of the apparatus and raw water is passed through the water softening tank 3. By passing raw water through the water softening tank 3, the acidic electrolyzed water in the water softening tank 3 is replaced with raw water or acidic soft water softened by the weakly acidic cation exchange resin 10. In the circulation flow path 20 during regeneration, the acidic electrolyzed water with a high concentration of hardness components is mainly held in the water softening tank 3. Therefore, in order to reduce the concentration of hardness components in the circulation flow path 20, the acidic electrolyzed water in the water softening tank 3 can be replaced.

[0091] Furthermore, in the first embodiment, during the replacement process, the raw water that has passed through the water softening tank 3 is passed through the separation section 14. This allows the replacement process to clean the separation section 14, and allows the acidic soft water generated in the water softening tank 3 to flow through the separation section 14, thereby dissolving the precipitates resulting from the hardness components separated in the separation section 14.

[0092] That is, in the replacement process shown in the first embodiment, the acidic electrolyzed water with a high concentration of hard components present in the water softening tank 3 is replaced with raw water, and the acidic electrolyzed water is discharged outside the apparatus, thereby reducing the concentration of hard components in the system. At this time, the raw water passed through the water softening tank 3 is passed through the separation unit 14, and the separation unit 14 is washed, whereby the precipitates deposited in the separation unit 14 can be dissolved and discharged outside the system.

[0093] Next, the operation of the water softening device 1 during replacement processing will be described with reference to the "Replacement" section in FIG.

[0094] 4, in the water softening device 1, in the replacement process, the on-off valve 31 and the on-off valve 41 are opened, and the selection valve 40 is switched to a flow path state in which water flows from the separation section 14 to the drainage flow path 26. As a result, the replacement flow path 27 is formed in the water softening device 1, and the separation section 14 is placed in a state in which it can be cleaned. At this time, the on-off valve 32 and the on-off valves 34 to 39 are closed.

[0095] Specifically, in the replacement process, as shown in FIG. 3 , raw water is supplied from an inlet 2 through a flow path 7 by the pressure of city water and supplied to a water softening tank 3. The raw water supplied to the water softening tank 3 then flows through a weakly acidic cation exchange resin 10 provided in the water softening tank 3. At this time, cations, which are hardness components in the raw water, are adsorbed by the weakly acidic cation exchange resin 10, and hydrogen ions are released (ion exchange occurs). The raw water is softened by removing the cations from the raw water. At this time, the water that flows out of the water softening tank 3 becomes acidic due to the release of hydrogen ions. In other words, the raw water that flows into the water softening tank 3 is discharged from the water softening tank 3 as acidic soft water. Furthermore, the acidic electrolyzed water present in the water softening tank 3 during the regeneration treatment is discharged from the water softening tank 3 by the inflowing raw water and the acidic softened water treated by the weakly acidic cation exchange resin 10, sent to the separation section 14, and finally discharged from the device through the drain outlet 16.

[0096] Next, since the on-off valve 41 is open and the on-off valves 32 and 36 are closed, the acidic softened water sent out from the water softening tank 3 flows through the flow path 8, the flow path 29, and the second supply flow path 23, and then flows into the separation section 14. By causing the acidic softened water to flow into the separation section 14, the precipitates caused by the hardness components captured in the separation section 14 react with the acidic softened water. As a result, the precipitates caused by the hardness components dissolve and become hardness components, which are contained in the acidic softened water.

[0097] Furthermore, since the water flow direction of the selection valve 40 is set toward the drain outlet 16 (the direction in which the water flows from the separation unit 14 to the drain outlet 16), the acidic soft water that has flowed through the separation unit 14 flows through the drain flow path 26 and is discharged from the drain outlet 16 to the outside of the device. In other words, by flowing the acidic soft water through the separation unit 14 and discharging the flowing acidic soft water, the separation unit 14 can be cleaned and hardness components can be discharged to the outside of the device. This allows the precipitates captured by the separation unit 14 to be dissolved and removed, and the separation unit 14 to be cleaned, thereby reducing a decrease in the amount of water passing through due to clogging of the separation unit 14.

[0098] At this time, until the acidic softened water reaches the separation section 14, the acidic electrolyzed water with a high concentration of hardness components that remained in the water softening tank 3 during the regeneration process flows through the separation section 14 first and can be discharged outside the device through the drain outlet 16.

[0099] The replacement process is initiated after a certain time (e.g., two hours) has elapsed since the start of the regeneration process. The replacement process may be performed only once during the regeneration process, or may be performed frequently. If the replacement process is not performed frequently during the regeneration process, it is preferable to perform the replacement process in the latter half of the regeneration process. This is because the concentration of hardness components in the acidic electrolyzed water introduced into the water softening tank 3 increases as the regeneration process progresses, and performing the replacement process in the latter half of the regeneration process increases the total amount of hardness components that can be discharged from the system in one replacement process. Also, when focusing on cleaning the separation unit 14, deposits gradually accumulate over time from the start of the regeneration process, so it is preferable to perform the replacement process in the latter half of the regeneration process. For example, if the regeneration process requires six hours and the replacement process is performed only once, the replacement process may be performed three hours or more after the start of the regeneration process.

[0100] The replacement process is terminated after a certain time (e.g., 5 minutes) has elapsed since the start of the replacement process. The certain time is the time required to discharge the acidic electrolyzed water with a high concentration of hardness components remaining in the water softening tank 3 and to dissolve a certain amount of the precipitates captured by the separation unit 14, and is set based on the evaluation results of a cleaning experiment previously conducted.

[0101] When the replacement process is completed, the water softening device 1 opens the on-off valves 35 to 39 and closes the on-off valves 31 and 41 in order to resume the regeneration process that was temporarily stopped. Furthermore, the selection valve 40 connects the flow path in the direction in which the water that has flowed through the separation section 14 flows to the neutralization tank 4, and the operation of the electrode 13 and the water pump 19 is resumed, thereby restarting the regeneration process.

[0102] The replacement process may be performed multiple times before the playback process ends.

[0103] After that, in the water softening device 1, when the regeneration treatment is completed, the operation of the electrodes 13 is stopped and the process shifts to the wastewater treatment.

[0104] (Wastewater treatment) When the regeneration process is completed, the water softening device 1 shifts to the wastewater process. Here, the wastewater process is a process of discharging the raw water, acidic electrolyzed water, alkaline electrolyzed water, and acidic soft water remaining in the circulation flow path 20.

[0105] Next, the operation of the water softening device 1 during wastewater treatment will be described with reference to the "during wastewater treatment" section of FIG.

[0106] In the water softening device 1, as shown in Fig. 4, during wastewater treatment (during discharge), the on-off valves 31, 32, 34, and 41 are closed, and the on-off valves 35 to 39 are opened. The water flow direction of the selection valve 40 is set to the direction toward the drain outlet 16 (the direction from the separation unit 14 to the drain outlet 16). This stops the inflow of city water from the inlet 2, and allows the acidic electrolyzed water remaining in the path from the electrolytic cell 12 to the water tank 15 via the first supply flow path 21, the water softening tank 3, and the first recovery flow path 22, and the alkaline electrolyzed water remaining in the path from the separation unit 14 to the water tank 15 via the second supply flow path 23, the neutralization tank 4, and the second recovery flow path 24, to flow into the water tank 15.

[0107] Next, the water pump 19 is started, the on-off valve 39 is opened, and the flow direction of the selection valve 40 is switched to the direction of the drain outlet 16. This allows the electrolyzed water remaining in the path from the inside of the water storage tank 15 via the water supply flow path 25 to the electrolytic cell 12, the electrolyzed water remaining in the path from the inside of the electrolytic cell 12 via the second supply flow path 23 and the drain flow path 26 to the drain outlet 16, and the raw water and acidic soft water remaining in the exchange flow path 27 to be discharged outside the device. At this time, the electrode 13 is stopped operating.

[0108] Then, in the water softening device 1, when the drainage treatment is completed, the operation of the water pump 19 is stopped. Also, the on-off valves 35 to 39 are closed, the on-off valves 31, 32, and 34 are opened, and the water flow direction of the selection valve 40 is set to the direction of the neutralization tank 4 (the direction from the separation section 14 to the neutralization tank 4), thereby transitioning to the water softening treatment.

[0109] The drainage process is considered to end when a certain time (for example, one minute) has elapsed since the start of the drainage process.

[0110] (Water softening treatment) When the drainage treatment is completed, the water softening device 1 shifts to the water softening treatment.

[0111] The operation of the water softening device 1 during water softening treatment will be described with reference to the "water softening" section of FIG.

[0112] 4, in the water softening process, the on-off valve 34 provided at the water intake 5 is opened while the on-off valves 31 and 32 are open. As a result, in the water softening device 1, city water (raw water containing hardness components) from the outside flows through the water softening tank 3 and the neutralization tank 4, and softened water (neutral soft water) can be taken out from the water intake 5.

[0113] Specifically, in the water softening process, raw water is supplied from inlet 2 through flow path 7 to water softening tank 3 under the pressure of city water. The raw water then flows through weakly acidic cation exchange resin 10 provided in water softening tank 3. The cations, which are hardness components in the raw water, are adsorbed by weakly acidic cation exchange resin 10, and hydrogen ions are released (ion exchange occurs). The raw water is then softened by removing the cations from the raw water. The softened water then flows through flow path 8 to neutralization tank 4. In neutralization tank 4, weakly basic anion exchange resin 11 adsorbs hydrogen ions contained in the softened water. As hydrogen ions are removed from the treated softened water, the pH rises, turning it into neutral water suitable for domestic use. The softened water then flows through flow path 9 and can be extracted from water intake 5. At this time, on-off valves 35 to 39 are all closed. Furthermore, the electrodes 13 of the electrolytic cell 12 and the water pump 19 are also stopped.

[0114] Then, in the water softening device 1, when the time period specified by the control unit 17 is reached or when the water softening process has continued for a certain period of time, the water softening process is stopped and the above-mentioned regeneration process is carried out.

[0115] In this way, the regeneration process, replacement process, and water softening process are repeatedly performed in the water softening device 1. The water softening device 1 converts city water (raw water containing hardness components) into neutral soft water that can be used for daily life and supplies it.

[0116] As described above, the water softening device 1 according to the first embodiment can provide the following effects.

[0117] (1) The water softening device 1 includes a water softening tank 3, a neutralization tank 4, and an electrolytic tank 12. The water softening tank 3 softens raw water containing hardness components and chloride ions using a weakly acidic cation exchange resin 10. The neutralization tank 4 neutralizes the pH of the softened water that has passed through the water softening tank 3 using a weakly basic anion exchange resin 11. The electrolytic tank 12 generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 10 in the water softening tank 3, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin 11 in the neutralization tank 4. The water softening device 1 is configured to perform a water replacement process in which raw water is passed through the water softening tank 3 during the regeneration process of the water softening tank 3.

[0118] As a result, during the regeneration process, the water in the water softening tank 3 can be replaced with raw water from the acidic electrolyzed water containing a large amount of hardness components released from the weakly acidic cation exchange resin 10. Therefore, the amount of hardness components in the regeneration process path can be reduced, and a water softening device 1 can be provided that can prevent the time required for the regeneration process of the water softening device 1 from becoming long.

[0119] (2) The water softener 1 further includes a separation unit 14. The separation unit 14 is provided in a flow path connecting the electrolytic tank 12 and the neutralization tank 4, and separates precipitates resulting from hardness components contained in the water introduced into the electrolytic tank 12. In the replacement process, raw water that has flowed through the water softening tank 3 is passed through the separation unit 14. This allows the separation unit 14 to be washed using the acidic soft water that has flowed through the water softening tank 3, and allows the precipitates containing hardness components that have been deposited in the separation unit 14 to be dissolved. This reduces pressure loss in the separation unit 14, allows a sufficient amount of alkaline electrolyzed water to be supplied to the neutralization tank 4, and allows the water softener 1 to smoothly perform the regeneration process.

[0120] (3) In the water softening device 1, the replacement process is terminated after a certain period of time has elapsed since the start of the replacement process. This allows the acidic electrolyzed water with a high concentration of hardness components remaining in the water softening tank 3 to be discharged to the outside of the device within a certain period of time, and the cleaning process of the separation unit 14 to be completed. This prevents the temporary stoppage time of the regeneration process from becoming excessively long.

[0121] (Embodiment 2) Next, a water softening device 1a according to a second embodiment of the present invention will be described with reference to Figs. 5 to 8. Fig. 5 is a conceptual diagram showing the configuration of the water softening device 1a according to the second embodiment. Fig. 6 is a configuration diagram showing the circulation flow path 20c of the water softening device 1a according to the second embodiment. Fig. 7 is a configuration diagram showing the exchange flow path 27a of the water softening device 1a according to the second embodiment. Fig. 8 is a diagram showing the state of the water softening device 1a according to the second embodiment during operation.

[0122] The water softening device 1a according to embodiment 2 differs from embodiment 1 in that it is configured to perform backwashing of the separation section 14 when cleaning the separation section. Other than this, the configuration of the water softening device 1a is the same as that of the water softening device 1 according to embodiment 1. Below, the contents already explained in embodiment 1 will be omitted as appropriate, and differences from embodiment 1 will be mainly explained.

[0123] (flow path and on-off valve) As shown in FIG. 5, the water softening device 1a is configured to include a plurality of on-off valves (on-off valves 31 to 39 and on-off valves 42 to 44). The plurality of on-off valves (on-off valves 31 to 39 and on-off valves 42 to 44) are provided in the respective flow paths, and switch between an "open" state and a "closed" state in each flow path. Furthermore, the water softening device 1a does not include a flow path equivalent to flow path 29 of the first embodiment. The water softening device 1a is configured to supply acidic soft water to the separation unit 14 through a second supply flow path 23 instead of flow path 29.

[0124] The second supply flow path 23 is a flow path that communicates with the electrolytic cell 12 and the flow path 8, and is provided with an on-off valve 42, an on-off valve 43, a separation unit 14, and an on-off valve 37. The second supply flow path 23 is also connected to the drainage flow path 26a between the on-off valve 42 and the on-off valve 43.

[0125] The on-off valve 42 is provided between the connection point between the second supply flow path 23 and the drainage flow path 26a and the electrolytic cell 12. The on-off valve 43 is provided between the connection point between the second supply flow path 23 and the drainage flow path 26a and the separation unit 14. The on-off valve 37 is provided between the connection point between the second supply flow path 23 and the flow path 8 and the separation unit 14. In other words, the alkaline electrolyzed water delivered from the electrolytic cell 12 during the regeneration process flows through the second supply flow path 23 in the order of the on-off valve 42, the on-off valve 43, the separation unit 14 and the on-off valve 37, and then flows into the flow path 8.

[0126] As shown in Figure 6, the circulation flow path 20c includes a first circulation flow path 20d through which water pumped from the water storage tank 15 by the water pump 19 flows through the water softening tank 3, and a second circulation flow path 20e through which water pumped from the water storage tank 15 by the water pump 19 flows through the neutralization tank 4.

[0127] 6 (white arrow), first circulation flow path 20d is a flow path through which water sent out from water tank 15 by water supply pump 19 flows through electrolytic cell 12 and water softening tank 3, and returns to water tank 15 for circulation. More specifically, first circulation flow path 20d is a flow path through which water sent out from water tank 15 by water supply pump 19 flows and circulates through water supply flow path 25, electrolytic cell 12, first supply flow path 21, on-off valve 35, water softening tank 3, first recovery flow path 22, on-off valve 36, and water tank 15 in this order.

[0128] As shown in Fig. 6 (black arrow), the second circulation flow path 20e is a flow path through which water sent out from the water tank 15 by the water supply pump 19 flows through the electrolytic cell 12 and the neutralization cell 4, and then returns to the water tank 15 for circulation. More specifically, the second circulation flow path 20e is a flow path through which water sent out from the water tank 15 by the water supply pump 19 flows and circulates, in this order, through the water supply flow path 25, the electrolytic cell 12, the second supply flow path 23, the on-off valve 42, the on-off valve 43, the separation unit 14, the on-off valve 37, the on-off valve 33, the neutralization cell 4, the second recovery flow path 24, the on-off valve 38, and the water tank 15. That is, in the water softening device 1a, the upstream side of the separation unit 14 is connected in communication with the downstream side of the electrolytic cell 12 during the regeneration treatment in which the second circulation flow path 20e is formed.

[0129] The water softening device 1a also includes a drainage flow path 26a. The drainage flow path 26a is a flow path for supplying water discharged from the electrolytic cell 12 or the separation unit 14 to the drain outlet 16 and discharging it to the outside of the device. The drainage flow path 26a is connected in communication with the second supply flow path 23 between the electrolytic cell 12 and the separation unit 14. An on-off valve 44 is provided in the drainage flow path 26a. By opening the on-off valve 44, the drainage flow path 26a is connected in communication with the second supply flow path 23. In other words, the water softening device 1a includes the drainage flow path 26a, which allows water to be drawn from the second supply flow path 23 to the drain outlet 16 and discharged to the outside of the device.

[0130] As shown in Fig. 7, replacement flow path 27a is made up of flow paths connecting inlet 2, water softening tank 3, separation unit 14, and drain outlet 16. That is, water softening tank 3 is connected in fluid communication with inlet 2 via flow path 7. Water softening tank 3 is also connected in fluid communication with separation unit 14 via flow path 8 and second supply flow path 23. Separation unit 14 is connected in fluid communication with drain outlet 16 via second supply flow path 23 and drain flow path 26a. Second supply flow path 23 is provided with separation unit 14, on-off valve 37, on-off valve 42, and on-off valve 43. 7 (diagonal arrow), replacement flow path 27a is a flow path through which water introduced from inlet 2 flows in this order through flow path 7 and water softening tank 3, is converted into acidic soft water in water softening tank 3, flows in this order through flow path 8, second supply flow path 23, and separation unit 14, is used to clean separation unit 14, flows through on-off valve 43 and drainage flow path 26, and is discharged to the outside of the device from drain outlet 16. In other words, in water softening device 1a, separation unit 14 is configured so that, during replacement processing, acidic soft water flows into separation unit 14 from the downstream side of separation unit 14, thereby performing backwashing.

[0131] (Regeneration treatment, replacement treatment, wastewater treatment, and water softening treatment) (Recycling) First, the operation of the regeneration device 6 of the water softening device 1a during regeneration treatment will be described in order with reference to the columns "Water injection" and "Regeneration" in FIG.

[0132] First, as shown in Fig. 8, when water is injected, the on-off valve 31 and the on-off valve 36 are opened. As a result, the water softening device 1 introduces raw water from the inlet 2 through the water softening tank 3 into the water tank 15 by the pressure of city water. At this time, the on-off valves 32 to 35, the on-off valves 37 to 39, and the on-off valves 42 to 44 are closed. By storing a predetermined amount of water in the water tank 15 according to the capacity of the water softening device 1, the regeneration device 6 can ensure the amount of water required for regeneration.

[0133] Next, during regeneration, when on-off valve 31, on-off valve 32, on-off valve 34, and on-off valve 44 are closed and on-off valve 33, on-off valves 35 to 39, and on-off valves 42 to 43 are opened, first circulation flow path 20d and second circulation flow path 20e are formed, respectively.

[0134] Then, when the electrodes 13 of the electrolytic cell 12 and the water pump 19 are operated, the water stored in the water tank 15 is sent to the electrolytic cell 12, where it is electrolyzed into acidic electrolyzed water and alkaline electrolyzed water, which then circulate through the first circulation flow path 20d and the second circulation flow path 20e, respectively.

[0135] At this time, the acidic electrolyzed water produced in the electrolytic tank 12 is fed into the water softening tank 3 through the first supply flow path 21 and flows through the weakly acidic cation exchange resin 10 therein, thereby regenerating the weakly acidic cation exchange resin 10. After that, the acidic electrolyzed water containing cations that has flowed through the weakly acidic cation exchange resin 10 is collected into the water storage tank 15 through the first collection flow path 22.

[0136] Meanwhile, the alkaline electrolyzed water produced in the electrolytic cell 12 is fed into the neutralization cell 4 through the second supply flow path 23 and the separation part 14, and flows through the weakly basic anion exchange resin 11 therein, thereby regenerating the weakly basic anion exchange resin 11. After that, the alkaline electrolyzed water containing anions that has flowed through the weakly basic anion exchange resin 11 is recovered into the water tank 15 via the second recovery flow path 24.

[0137] Then, in the water storage tank 15, the acidic electrolyzed water containing cations recovered from the water softening tank 3 and the alkaline electrolyzed water containing anions recovered from the neutralization tank 4 are mixed and neutralized, and then sent to the electrolytic tank 12.

[0138] Thereafter, the electrolyzed water mixed in the water storage tank 15 is passed through the water supply flow path 25 again to the electrolytic cell 12. The passed water is then electrolyzed again in the electrolytic cell 12.

[0139] Then, in the water softening device 1a, the regeneration process is temporarily stopped while it is in progress. That is, the operation of the electrode 13 and the water pump 19 is stopped, the on-off valve 33, the on-off valves 35 to 36, and the on-off valves 38 to 42 are closed, and the on-off valves 31, 32, and 44 are opened, thereby transitioning to the replacement process.

[0140] (Replacement process) When the regeneration process is temporarily stopped, the water softening apparatus 1a transitions to a replacement process. Here, the replacement process is a process in which acidic electrolyzed water with a high concentration of hardness components remaining in the water softening tank 3 is discharged outside the apparatus, and raw water is passed through the water softening tank 3. In addition, in the second embodiment, during the replacement process, the raw water passed through the water softening tank 3 is passed through the separation section 14 from the downstream side of the separation section 14. In this way, by performing the replacement process, the separation section 14 can be backwashed, and the acidic soft water generated in the water softening tank 3 can be passed through the separation section 14, thereby dissolving the precipitates caused by the hardness components separated in the separation section 14. That is, in the replacement process shown in the second embodiment, the acidic electrolyzed water with a high concentration of hardness components present in the water softening tank 3 is replaced with raw water, and the acidic electrolyzed water is discharged outside the device, thereby reducing the concentration of hardness components in the system, and at the same time, the raw water passed through the water softening tank 3 is passed through the separation section 14, and the separation section 14 is back-washed, thereby dissolving the precipitates deposited in the separation section 14 and discharging them outside the system.

[0141] Next, the operation of the water softening device 1a during replacement processing will be described with reference to the "Replacement" section of FIG.

[0142] 8, in the water softening device 1a, the on-off valves 31, 32, 37, 43, and 44 are opened in the replacement process. As a result, the replacement flow path 27a is formed in the water softening device 1, and backwashing of the separation section 14 can be performed. At this time, the on-off valves 33 to 39 and the on-off valve 42 are closed.

[0143] As shown in Fig. 7, the on-off valves 32 and 37 are open, and the on-off valves 33 and 36 are closed, so that the acidic softened water delivered from the water softening tank 3 flows through the flow path 8 and the second supply flow path 23 and into the separation section 14. By allowing the acidic softened water to flow into the separation section 14, precipitates caused by hardness components captured in the separation section 14 react with the acidic softened water. As a result, the precipitates caused by hardness components dissolve and become hardness components that are contained in the acidic softened water.

[0144] Since the on-off valves 43 and 44 are open and the on-off valve 42 is closed, the acidic soft water discharged from the separation section 14 flows through the second supply flow path 23 and the drainage flow path 26a and is discharged outside the device through the drainage outlet 16.

[0145] At this time, until the acidic softened water reaches the separation section 14, the acidic electrolyzed water with a high concentration of hardness components that remained in the water softening tank 3 during the regeneration process flows through the separation section 14 first and is discharged outside the device through the drain outlet 16.

[0146] Then, in the water softening device 1a, when the replacement process is completed, in order to restart the regeneration process that was temporarily stopped, the on-off valve 33, the on-off valves 35 to 36, and the on-off valves 38 to 42 are opened, and the on-off valves 31, 32, and 44 are closed. Furthermore, the operation of the electrode 13 and the water pump 19 is restarted, and the regeneration process is restarted.

[0147] Thereafter, in the water softening device 1a, when the regeneration process is completed, the operation of the electrode 13 is stopped.

[0148] The replacement process is initiated after a certain time (e.g., two hours) has elapsed since the start of the regeneration process. The replacement process may be performed only once during the regeneration process, or may be performed frequently. If the replacement process is not performed frequently during the regeneration process, it is preferable to perform the replacement process in the latter half of the regeneration process. This is because the concentration of hardness components in the acidic electrolyzed water introduced into the water softening tank 3 increases as the regeneration process progresses, and performing the replacement process in the latter half of the regeneration process increases the total amount of hardness components that can be discharged from the system in one replacement process. Also, when focusing on cleaning the separation unit 14, deposits gradually accumulate over time from the start of the regeneration process, so it is preferable to perform the replacement process in the latter half of the regeneration process. For example, if the regeneration process requires six hours and the replacement process is performed only once, the replacement process may be performed three hours or more after the start of the regeneration process.

[0149] The replacement process is terminated after a certain time (e.g., 5 minutes) has elapsed since the start of the replacement process. The certain time is the time required to discharge the acidic electrolyzed water with a high concentration of hardness components remaining in the water softening tank 3 and to dissolve a certain amount of the precipitates captured by the separation unit 14, and is set based on the evaluation results of a cleaning experiment previously conducted.

[0150] When the replacement process is completed, the water softening device 1a opens the on-off valves 35 to 39 and the on-off valve 42 and closes the on-off valves 31, 32, and 44 in order to resume the regeneration process that was temporarily stopped. Furthermore, the operation of the electrode 13 and the water pump 19 is resumed, and the regeneration process is resumed.

[0151] The replacement process may be performed multiple times before the playback process ends.

[0152] After that, in the water softening device 1, when the regeneration treatment is completed, the operation of the electrodes 13 is stopped and the process shifts to the wastewater treatment.

[0153] (Wastewater treatment) In the water softening device 1a, once the regeneration process is completed, the process shifts to the wastewater process, which is a process of discharging the raw water, acidic electrolyzed water, alkaline electrolyzed water, and acidic soft water remaining in the circulation flow path 20c.

[0154] Next, the operation of the water softening device 1a during wastewater treatment will be described with reference to the "during wastewater treatment" section of FIG.

[0155] 8, in the water softening device 1a, during wastewater treatment (during discharge), the on-off valves 31, 32, and 34 are closed, and the on-off valves 35 to 39 and the on-off valves 42 to 44 are opened. This stops the inflow of city water from the inlet 2, and allows the acidic electrolyzed water remaining in the path from the electrolytic cell 12 to the water tank 15 via the first supply flow path 21, the water softening cell 3, and the first recovery flow path 22, and the alkaline electrolyzed water remaining in the path from the separation unit 14 to the water tank 15 via the second supply flow path 23, the neutralization cell 4, and the second recovery flow path 24, to flow into the water tank 15.

[0156] Next, the water pump 19 is started and the on-off valve 39 is opened. This allows the electrolyzed water remaining in the path from the inside of the water storage tank 15 via the water supply flow path 25 to the electrolytic cell 12, the electrolyzed water remaining in the path from the inside of the electrolytic cell 12 via the second supply flow path 23 and the drainage flow path 26 to the drain outlet 16, and the raw water and acidic soft water remaining in the exchange flow path 27a to be discharged outside the device. At this time, the electrode 13 is not operating.

[0157] Then, in the water softening device 1a, when the drainage treatment is completed, the operation of the water pump 19 is stopped. Also, the on-off valves 35 to 39 and the on-off valves 42 to 44 are closed, and the on-off valves 31, 32, and 34 are opened, thereby transitioning to the water softening treatment.

[0158] The drainage process is considered to end when a certain time (for example, one minute) has elapsed since the start of the drainage process.

[0159] (Water softening treatment) When the drainage treatment is completed, the water softening device 1a shifts to the water softening treatment.

[0160] The operation of the water softening device 1a during water softening treatment will be described with reference to the "water softening" section of FIG.

[0161] In the water softening apparatus 1a, as shown in Fig. 8, during the water softening process, the on-off valves 31 to 33 are open, and the on-off valve 34 provided at the water intake 5 is opened. As a result, in the water softening apparatus 1, city water (raw water containing hardness components) from the outside flows through the water softening tank 3 and the neutralization tank 4, and softened water (neutral soft water) can be taken out from the water intake 5. At this time, the on-off valves 35 to 39 and the on-off valves 42 to 44 are all closed. In addition, the operation of the electrode 13 of the electrolytic tank 12 and the water pump 19 is stopped.

[0162] Then, in the water softening device 1a, when the time period specified by the control unit 17 is reached or when the water softening process has continued for a certain period of time, the water softening process is stopped and a regeneration process is carried out.

[0163] In this manner, the water softening device 1a repeatedly performs the regeneration process, the replacement process, and the water softening process.

[0164] As described above, according to the water softening device 1a of the second embodiment, in addition to the effects (1) to (3) obtained by the first embodiment, the following effects can be obtained.

[0165] (4) In the water softening device 1a, in the replacement process, raw water that has passed through the water softening tank 3 is configured to flow into the separation unit 14 from the downstream side of the separation unit 14. As a result, raw water that has been turned into acidic soft water by the water softening tank 3 flows into the separation unit 14 from the downstream side. Since electrolyzed water containing precipitates caused by hardness components flows into the separation unit 14 from the upstream side of the separation unit 14, backwashing of the separation unit 14 can be performed by flowing acidic soft water from the downstream side. Therefore, the processing efficiency of the replacement process can be improved, and the replacement process can be completed in a shorter time.

[0166] (Embodiment 3) Next, a water softening device 1b according to a third embodiment of the present invention will be described with reference to Fig. 9. Fig. 9 is a conceptual diagram showing the configuration of a water softening device according to the third embodiment.

[0167] The water softening device 1b according to the third embodiment differs from the first embodiment in that it includes a flow rate detection unit 45 after the separation unit 14 and before the selection valve 40. That is, the water softening device 1b according to the third embodiment controls the regeneration process to be temporarily stopped and the replacement process to be performed when the flow rate of the alkaline electrolyzed water after flowing through the separation unit 14 falls below a predetermined value. Other than this, the configuration and control of the water softening device 1b are the same as those of the water softening device 1 according to the first embodiment. Below, the contents already explained in the first embodiment will be omitted as appropriate, and the differences from the first embodiment will be mainly explained.

[0168] As shown in FIG. 9, the water softening device 1b includes a flow rate detection unit 45 on the second supply flow path 23, after the separation unit 14 and before the selection valve 40.

[0169] The flow rate detection unit 45 detects the flow rate information of alkaline electrolyzed water that has passed through the separation unit 14 during the regeneration process. Here, the degree of deposition of deposits in the separation unit 14 can be determined according to the flow rate detected by the flow rate detection unit 45. Specifically, when the flow rate is high, it can be said that the separation unit 14 is not clogged and the regeneration process is not being hindered. On the other hand, when the flow rate is low, it can be determined that the deposition of deposits in the separation unit 14 has caused clogging of the separation unit 14, resulting in a decrease in the flow rate of alkaline electrolyzed water, and a replacement process is performed. In addition, the flow rate detection unit 45 is connected to the control unit 17 wirelessly or via a wired connection so that information on the detected flow rate is used as an input signal for the control unit 17.

[0170] Here, a general-purpose device can be used as the flow rate detection unit 45, and an example of this is a propeller-type flow meter.

[0171] During the regeneration process, the control unit 17 controls the regeneration process to be temporarily stopped and to proceed to the replacement process when the flow rate falls below a predetermined value based on the information on the flow rate output from the flow rate detection unit 45. This allows the control unit 17 to determine whether to temporarily stop the regeneration process and start the replacement process based on the flow rate of alkaline electrolyzed water after it has flowed through the separation unit 14. In other words, when the flow rate of alkaline electrolyzed water decreases due to deposits deposited in the separation unit 14, the replacement process can be started.

[0172] As described above, according to the water softening device 1b of the third embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be obtained.

[0173] (5) The water softening device 1b is provided with a flow rate detector 45 that detects the flow rate of water flowing through the separation unit 14, and is configured to start the replacement process when the flow rate detected by the flow rate detector 45 falls below a predetermined value. This makes it possible to grasp the flow rate status of water flowing through the separation unit 14 during the regeneration process, and to determine whether to start the replacement process based on the flow rate information. In other words, the degree of clogging of the separation unit 14 during the regeneration process can be grasped based on the flow rate of water flowing through the separation unit 14. This allows the regeneration process to be temporarily stopped and the replacement process to be started at more effective timing.

[0174] (Fourth embodiment) Next, a water softening device 1c according to a fourth embodiment of the present invention will be described with reference to Fig. 10. Fig. 10 is a conceptual diagram showing the configuration of a water softening device according to the fourth embodiment.

[0175] The water softening device 1c according to the fourth embodiment differs from the first embodiment in that it includes a static pressure detection unit 46 upstream of the separation unit 14. That is, in the water softening device 1c according to the fourth embodiment, when the static pressure exceeds a predetermined value based on the static pressure of the alkaline electrolyzed water before it flows through the separation unit 14, that is, when the flow rate of the alkaline electrolyzed water flowing into the separation unit 14 decreases, the regeneration process is temporarily stopped and a replacement process is performed. Other than this, the configuration and control of the water softening device 1c are the same as those of the water softening device 1 according to the first embodiment. Hereinafter, the contents already explained in the first embodiment will be omitted as appropriate, and differences from the first embodiment will be mainly explained.

[0176] As shown in FIG. 10, the water softening device 1c includes a static pressure detection unit 46 on the second supply flow path 23, upstream of the separation unit 14.

[0177] During the regeneration process, the static pressure detection unit 46 detects static pressure information of the alkaline electrolyzed water before it passes through the separation unit 14. In this embodiment, since the water pump 19 operates at a constant capacity, the static pressure decreases when the flow rate of alkaline electrolyzed water is high, and increases when the flow rate is low. Therefore, the static pressure detected by the static pressure detection unit 46 changes depending on the pressure loss in the flow path of the water pump 19. In other words, the degree of deposition of deposits in the separation unit 14 can be determined depending on the static pressure detected by the static pressure detection unit 46. Specifically, when the static pressure is low, it can be said that the separation unit 14 is not clogged and the regeneration process is not being hindered. On the other hand, when the static pressure is high, it can be determined that the deposition of deposits in the separation unit 14 has caused clogging, resulting in a decrease in the flow rate of alkaline electrolyzed water, and a replacement process is performed. The static pressure detection unit 46 is also connected to the control unit 17 via wired or wireless communication, and the detected flow rate information is used as an input signal for the control unit 17.

[0178] Here, the static pressure detection unit 46 can be a general-purpose one, such as a digital pressure sensor.

[0179] During the regeneration process, if the static pressure exceeds a predetermined value based on the information on the static pressure output from the static pressure detection unit 46, that is, if the flow rate of the alkaline electrolyzed water flowing into the separation unit 14 decreases, the control unit 17 controls the regeneration process to be temporarily stopped and to transition to the replacement process. This allows the control unit 17 to determine whether to temporarily stop the regeneration process and start the replacement process based on the static pressure before the water flows through the separation unit 14.

[0180] As described above, according to the water softening device 1c of the fourth embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be obtained.

[0181] (6) The water softening device 1c is provided with a static pressure detection unit 46 that detects the static pressure of the flowing water upstream of the separation unit 14, and is configured to perform replacement processing when the static pressure detected by the static pressure detection unit 46 exceeds a predetermined value. This makes it possible to grasp the static pressure state of the separation unit 14 during regeneration processing, and to determine whether to start replacement processing based on the static pressure detection information. In other words, the degree of clogging of the separation unit 14 during regeneration processing can be grasped based on the static pressure of the water before it passes through the separation unit 14. This allows the regeneration processing to be temporarily stopped and replacement processing to be started at more effective timing.

[0182] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present invention.

[0183] In the water softening apparatus 1 according to the first embodiment, raw water is passed through the water softening tank 3 during replacement, thereby discharging the acidic electrolyzed water in the water softening tank 3 to the outside of the apparatus, but this is not limiting. For example, raw water may also be passed through the neutralization tank 4, or the water in the circulation flow path 20 may be replaced with raw water. Furthermore, for example, by performing a wastewater treatment, the acidic electrolyzed water and alkaline electrolyzed water in the water softening apparatus 1 are discharged to the outside of the apparatus, and a treatment for water injection is performed, so that raw water is introduced into the water softening apparatus 1 before the circulation flow path 20 is formed. This allows the concentration of hardness components in the water softening apparatus 1 to be further reduced.

[0184] Furthermore, in the water softening apparatus 1 according to the first embodiment, there is one each of the water softening tank 3 and neutralization tank 4, but this is not limited to this. For example, a plurality of (for example, two) water softening tanks 3 and neutralization tanks 4 may be provided, or two water softening tanks 3 and one neutralization tank 4 may be provided. In this case, during replacement processing, raw water may be introduced into multiple water softening tanks 3, or only one may be selected and introduced into it. By providing a plurality of water softening tanks 3 and neutralization tanks 4, it is possible to improve water softening performance. [Industrial Applicability]

[0185] The water softening device according to the present invention can be applied to a point-of-use (POU) water purification device or a point-of-entry (POE) water purification device. [Explanation of symbols]

[0186] 1 Water softener 1a Water softener 1b Water softener 1c water softener 2 Inlet 3 Water softening tank 4 Neutralization tank 5. Water intake 6 Playback device 7 Flow path 8 Flow path 9 Flow path 10. Weakly acidic cation exchange resin 11 Weakly basic anion exchange resin 12 Electrolytic cell 13 electrodes 13a electrode 13b Electrode 14 Separation part 15 Water Tank 16 Drain 17 Control Unit 19 Water pump 20 Circulation flow path 20a First circulation channel 20b Second circulation channel 20c Circulation flow path 20d First circulation channel 20e Second circulation channel 21 First supply channel 22 First recovery channel 23 Second supply channel 24 Second recovery channel 25 Water supply channel 26 Drainage channel 26a Drainage channel 27 Replacement channel 27a Replacement channel 29 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 40 Selector valve 41 On-off valve 42 On-off valve 43 On-off valve 44 On-off valve 45 Flow rate detector 46 Static pressure detection unit

Claims

1. a water softening tank that softens raw water containing hardness components using a weakly acidic cation exchange resin; a neutralization tank for neutralizing the pH of the softened water that has passed through the water softening tank with a weakly basic anion exchange resin; an electrolytic tank for producing acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening tank and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization tank; a separation unit provided in a flow path connecting the electrolytic bath and the neutralization bath, which separates precipitates resulting from the hardness components contained in the water introduced into the electrolytic bath; Equipped with During the regeneration treatment of the water softening tank, a replacement treatment is performed in which the raw water is passed through the water softening tank; In the replacement process, the raw water that has passed through the water softening tank is passed through the separation section without passing through the neutralization tank.

2. The water softening apparatus according to claim 1, wherein in the replacement process, the raw water that has flowed through the water softening tank is introduced into the separation section from a downstream side of the separation section.

3. a flow rate detection unit that detects the flow rate of water flowing through the separation unit; 3. The water softening apparatus according to claim 1, wherein the replacement process is started when the flow rate detected by the flow rate detection unit falls below a predetermined value.

4. a static pressure detection unit for detecting the static pressure of the flowing water, provided in a stage preceding the separation unit; 3. The water softening apparatus according to claim 1, wherein the replacement process is performed when the static pressure detected by the static pressure detection unit exceeds a predetermined value.

5. A water storage tank is provided for mixing and storing the acidic electrolyzed water that has passed through the water softening tank and the alkaline electrolyzed water that has passed through the neutralization tank, 2. The water softening apparatus according to claim 1, wherein in the replacement process, the raw water that has flowed through the water softening tank is passed through the separation section without passing through the water storage tank.

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