Softening device

Abstract

To provide a water softening apparatus capable of reliably removing precipitates separated in a separation part in a cleaning process for separating precipitates generated in an electrolysis tank.SOLUTION: A water softening apparatus 1 has a water softening tank 3 in which raw water containing hardness components is softened by a weakly acidic cation exchange resin 10, a neutralization tank 4 in which the pH of the softened water that has passed through the water softening tank is neutralized by a weakly basic anion exchange resin 11, an electrolysis tank 12 in which acidic electrolysis water for regeneration of the weakly acidic cation exchange resin 10 and alkaline electrolysis water for regeneration of the weakly basic anion exchange resin 11, and a separation part 14 provided in the flow path connecting the electrolytic tank 12 and the neutralization tank 4 to separate precipitates caused by hardness components in the water introduced into the electrolytic tank 12. The water softening apparatus 1 performs a separation part cleaning process in which, after the regeneration process of the water softening tank 3 and the neutralization tank 4, the acidic softened water that has circulated through the water softening tank 3 is distributed to the separation part 14 and discharged outside the apparatus.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water softening device for obtaining domestic water.

Background Art

[0002] In a conventional water softening device using a weakly acidic cation exchange resin, as a method for regenerating the cation exchange resin without using salt, a method of regenerating the cation exchange resin with acidic electrolyzed water generated by electrolysis is known (for example, see Patent Document 1). The weakly acidic cation exchange resin has a proton at the end of the functional group, and exchanges hardness components (for example, calcium ions, magnesium ions) in raw water with hydrogen ions to soften the raw water. Then, the hydrogen ions in the water softened by the weakly acidic cation exchange resin are neutralized by being adsorbed by a weakly basic anion exchange resin provided downstream of the weakly acidic cation exchange resin. In a conventional water softening device, as a method for regenerating the weakly basic anion exchange resin, a method of regenerating the weakly basic anion exchange resin with alkaline electrolyzed water generated by electrolysis is known (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a conventional water softening device, during the regeneration process, hardness components (for example, calcium ions and magnesium ions) released from the water softening tank may react with alkaline electrolyzed water in the electrolysis tank to form precipitates. If such precipitates flow into the neutralization tank and accumulate in the neutralization tank and then the water softening treatment is resumed, there is a problem that the water softening performance deteriorates. As a countermeasure, it is effective to provide a separation section in the front stage of the neutralization tank to prevent the inflow of precipitates into the neutralization tank, but it is necessary to periodically perform a cleaning treatment to remove the precipitates separated by the separation section.

[0005] The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a water softening device capable of surely removing precipitates separated by a separation section in a cleaning treatment of the separation section that separates precipitates generated in an electrolysis tank.

Means for Solving the Problems

[0006] And, in order to achieve this object, the water softening device according to the present invention includes a water softening tank, a neutralization tank, an electrolysis tank, and a separation section. The water softening tank softens raw water containing hardness components with a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water that has passed through the water softening tank with a weakly basic anion exchange resin. The electrolysis 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 communicating the electrolysis tank and the neutralization tank, and separates precipitates caused by hardness components contained in the water introduced into the electrolysis tank. Then, after performing the regeneration treatment of the water softening tank and the neutralization tank, the water softening device performs a separation section cleaning treatment in which the acidic softened water that has flowed through the water softening tank is made to flow through the separation section and discharged outside the device. Thereby, the intended object is achieved.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a water softening device capable of surely removing precipitates separated by a separation section in a cleaning treatment of the separation section that separates precipitates generated in an electrolysis tank.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] The water softening device according to the present invention includes a water softening tank, a neutralization tank, an electrolysis tank, and a separation unit. The water softening tank softens raw water containing hardness components and chloride ions with a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water that has passed through the water softening tank with a weakly basic anion exchange resin. The electrolysis 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 unit is provided in a flow path communicating the electrolysis tank and the neutralization tank, and separates precipitates caused by hardness components contained in the water introduced into the electrolysis tank. Then, after performing the regeneration treatment of the water softening tank and the neutralization tank, the water softening device performs a separation unit cleaning treatment in which the acidic softened water that has flowed through the water softening tank is caused to flow through the separation unit and discharged outside the device.

[0010] According to such a configuration, it is possible to dissolve the precipitate separated by the separation unit using the acidic softened water softened by the water softening tank, and to clean the separation unit. Therefore, the separation unit can be reliably cleaned, and a water softening device that can be used over a long period of time can be obtained.

[0011] Further, in the water softening device according to the present invention, the separation unit cleaning treatment may be performed by causing a part of the acidic softened water that has flowed through the water softening tank to flow through the separation unit during the period in which the raw water is being softened by the water softening tank and the neutralization tank. By doing so, the cleaning treatment of the separation unit can be performed in parallel with the water softening treatment. Therefore, compared with the case where the water softening treatment is performed after the separation unit cleaning treatment, the water softening treatment can be executed for a longer time.

[0012] Further, in the water softening device according to the present invention, the separation unit cleaning treatment may be performed by causing acidic softened water to flow into the separation unit from the downstream side of the separation unit. By doing so, backwashing of the separation unit can be performed. Therefore, the treatment efficiency of the separation unit cleaning treatment can be improved, and the separation unit cleaning treatment can be completed in a shorter period of time.

[0013] In addition, in the water softening device according to the present invention, when the separation unit cleaning process is completed, the flow of acidic soft water to the separation unit may be stopped. By doing so, the supply of acidic soft water to the separation unit that exceeds the amount required for the separation unit cleaning process can be suppressed. Therefore, the separation unit cleaning process can be completed without using excessive acidic soft water.

[0014] In addition, in the water softening device according to the present invention, the end of the separation unit cleaning process may be set to be after a certain period from the start of the separation unit cleaning process. By doing so, the cleaning process of the separation unit can be completed within a certain period, so that insufficient cleaning of the separation unit or excessive use of acidic soft water can be suppressed.

[0015] In addition, the water softening device according to the present invention may further include an ion concentration detection unit that detects ion concentration information regarding the ion concentration of the water flowing out of the separation unit, and the end of the separation unit cleaning process may be performed based on the ion concentration information. By doing so, the cleaning state of the separation unit 14 during the separation unit cleaning process can be grasped, and the end of the separation unit cleaning process can be determined based on the ion concentration information. Therefore, the cleaning of the separation unit 14 can be completed more reliably.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are an example of embodying the present invention and do not limit the technical scope of the present invention. Also, each drawing described in the embodiments is a schematic diagram, and the ratio of the size and thickness of each component in each drawing does not necessarily reflect the actual dimensional ratio.

[0017] (Embodiment 1) With reference to FIG. 1, the water softening device 1 according to Embodiment 1 of the present invention will be described. FIG. 1 is a conceptual diagram showing the configuration of the water softening device 1 according to Embodiment 1 of the present invention. Note that in FIG. 1, each element of the water softening device 1 is conceptually shown.

[0018] (Overall Configuration) The water softening device 1 is a device that generates the municipal water (raw water containing hardness components) supplied from the outside into neutral soft water that can be used as domestic water.

[0019] 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, a water intake 5 for the treated soft water, and a regeneration device 6. Further, the regeneration device 6 includes an electrolytic cell 12, a separation unit 14, a water storage tank 15, and a water supply pump 19. Also, the water softening device 1 includes a drain port 16, a control unit 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.

[0020] The inlet 2 is connected to the municipal water. The water softening device 1 can take out the water after the water softening treatment from the water intake 5 by the pressure of the municipal water.

[0021] From the inlet 2 to the water intake 5, they are connected by a flow path 7, a flow path 8, and a flow path 9. The flow path 7 is a flow path connecting from the inlet 2 to the water softening tank 3. The flow path 8 is a flow path connecting from the water softening tank 3 to the neutralization tank 4. The flow path 9 is a flow path connecting from the neutralization tank 4 to the water intake 5.

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

[0023] That is, in the water softening device 1, in the water softening treatment, the municipal water supplied from the outside flows in the order of the inlet 2, the flow path 7, the water softening tank 3, the flow path 8, the neutralization tank 4, the flow path 9, and the water intake 5, 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, the weakly acidic cation exchange resin 10 is not particularly limited, and general-purpose ones can be used. For example, those having a carboxyl group (-COOH) as an exchange group can be mentioned. Also, the hydrogen ion ( H + ) that is the counter ion of the carboxyl group may be a cation such as a metal ion or an ammonium ion ( NH 4 + ).

[0026] Also, the weakly basic anion exchange resin 11 is not particularly limited, and general-purpose ones can be used. For example, those in the free base form can be mentioned.

[0027] The water softening tank 3 softens raw water containing hardness components by the action of the weakly acidic cation exchange resin 10. More specifically, the water softening tank 3 is equipped with a weakly acidic cation exchange resin 10 having a hydrogen ion at the end of the functional group. 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, so that the hardness of the raw water is reduced and the raw water can be softened. Also, since the end of the functional group of the weakly acidic cation exchange resin 10 is a hydrogen ion, in the regeneration treatment described later, the weakly acidic cation exchange resin 10 can be regenerated using acidic electrolyzed water. At this time, cations, which are the hardness components taken in during the water softening treatment, are released from the weakly acidic cation exchange resin 10.

[0028] Raw water containing hardness components is passed through the water softening tank 3 from the flow path 7 and passes through the weakly acidic cation exchange resin 10 filled inside, so that the raw water containing hardness components is passed as softened water to the neutralization tank 4 via the flow path 8. However, the softened water treated with the weakly acidic cation exchange resin 10 contains a large amount of hydrogen ions that have been exchanged with the hardness components. That is, the softened water flowing out from the water softening tank 3 is softened water (acidic softened water) containing a large amount of hydrogen ions and acidified.

[0029] The neutralization tank 4 neutralizes the pH of the soft water (acidified soft water) containing hydrogen ions coming out of the softening tank 3 by the action of the weakly basic anion exchange resin 11 and converts it into neutral water (neutral soft water). More specifically, the neutralization tank 4 is equipped with the weakly basic anion exchange resin 11, and adsorbs the hydrogen ions contained in the soft water from the softening tank 3 together with anions (negative ions), so that the pH of the soft water rises and neutral soft water can be obtained. Also, the weakly basic anion exchange resin 11 can be regenerated using alkaline electrolyzed water in the regeneration process described later.

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

[0031] (Regeneration device) The regeneration device 6 is a device for regenerating the weakly acidic cation exchange resin 10 of the softening tank 3 and the weakly basic anion exchange resin 11 of the neutralization tank 4. Specifically, as described above, the regeneration device 6 includes an electrolytic cell 12, a separation unit 14, a water storage tank 15, and a water supply pump 19. And the regeneration device 6 is connected to the flow paths 7, 8, and 9 from the inlet 2 to the water intake 5 by a first supply flow path 21, a first recovery flow path 22, a second supply flow path 23, a second recovery flow path 24, and a flow path 29, respectively. And each flow path constitutes a circulation flow path 20 (first circulation flow path 20a, second circulation flow path 20b) or a separation unit cleaning flow path 27 described later.

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

[0033] (Electrolytic cell) The electrolytic cell 12 uses a pair of electrodes 13 (electrode 13a and electrode 13b) provided inside to electrolyze the incoming water (the water supplied from the water storage tank 15), thereby generating and discharging acidic electrolyzed water and alkaline electrolyzed water. More specifically, at the electrode 13a that becomes the anode during electrolysis, hydrogen ions are generated by electrolysis, and acidic electrolyzed water is produced. Also, at the electrode 13b that becomes the cathode during electrolysis, hydroxide ions are generated by electrolysis, and alkaline electrolyzed water is produced. Then, the electrolytic cell 12 supplies the acidic electrolyzed water to the softening tank 3 via the first supply channel 21, and supplies the alkaline electrolyzed water to the neutralization tank 4 via the second supply channel 23. Although details will be described later, the acidic electrolyzed water generated by the electrolytic cell 12 is used for the regeneration of the weakly acidic cation exchange resin 10 in the softening tank 3, and the alkaline electrolyzed water generated by the electrolytic cell 12 is used for the regeneration of the weakly basic anion exchange resin 11 in the neutralization tank 4. Note that the electrolytic cell 12 is configured to be able to control the energization state to the pair of electrodes 13 by a control unit 17 described later.

[0034] (Water storage tank) The water storage tank 15 secures and stores the water that circulates in the circulation channel 20 (see Fig. 2) when regenerating the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11. Also, the water storage tank 15 mixes the acidic electrolyzed water containing hardness components that has flowed through the softening tank 3 and the alkaline electrolyzed water containing anions that has flowed through the neutralization tank 4, and supplies it to the electrolytic cell 12.

[0035] Then, the water that has flowed through the water storage tank 15 is passed through the electrolytic cell 12, electrolyzed in the electrolytic cell 12, and becomes acidic electrolyzed water and alkaline electrolyzed water, which are respectively supplied to the softening tank 3 and the neutralization tank 4. And the acidic electrolyzed water and the alkaline electrolyzed water are respectively reused in the softening tank 3 and the neutralization tank 4, and then passed through (recovered) back to the water storage tank 15 again. Therefore, the acidic electrolyzed water and the alkaline electrolyzed water used for the regeneration of the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11 can be reused.

[0036] (Water supply pump) The water supply pump 19 is a device that circulates water through the circulation channel 20 (see Fig. 2) during the regeneration process by the regeneration device 6. The water supply pump 19 is provided in the water supply channel 25 that communicatively connects between the water storage tank 15 and the electrolytic cell 12. Note that the water supply pump 19 is preferably arranged on the upstream side of the electrolytic cell 12 and on the downstream side of the water storage tank 15. Such an arrangement is because it becomes easier to circulate water through the first circulation channel 20a and the second circulation channel 20b with a single water supply pump 19. Also, the water supply pump 19 is communicatively connected to a control unit 17, which will be described later, by wireless or wired means.

[0037] (Separation section) The separation unit 14 is provided in a second supply channel 23 that communicatively connects the electrolytic cell 12 and the neutralization tank 4. The separation unit 14 separates precipitates contained in the alkaline electrolyzed water sent out from the electrolytic cell 12. Here, the precipitates are reaction products generated by the reaction of hardness components, which are cations released from the softening tank 3 during the regeneration process in the electrolytic cell 12, with the alkaline electrolyzed water. More specifically, while water electrolysis is being performed in the electrolytic cell 12, the hardness components (e.g., calcium ions, magnesium ions) released from the softening tank 3 during the regeneration process move to the cathode (electrode 13b) side. Since alkaline electrolyzed water is generated on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates. For example, when the hardness component is calcium ions, reactions occur to form calcium carbonate or calcium hydroxide by mixing with the alkaline electrolyzed water. Then, the precipitates derived from the hardness components are separated as precipitates by the separation unit 14 provided in the second supply channel 23. By separating the precipitates derived from the hardness components by the separation unit 14, it is possible to suppress the inflow and deposition of the precipitates into the neutralization tank 4. Therefore, when restarting the softening treatment after the completion of the regeneration process, it is possible to suppress the reaction of the precipitates deposited in the neutralization tank 4 with the hydrogen ions released from the softening tank 3 to form hardness components and increase the hardness of the soft water sent out from the neutralization tank 4. Also, during the regeneration process, the alkaline electrolyzed water from which the precipitates derived from the hardness components have been separated by the separation unit 14 flows through the neutralization tank 4, is mixed with the acidic electrolyzed water, and then is electrolyzed again in the electrolytic cell 12, and is used for the regeneration of the weakly acidic cation exchange resin 10 and the regeneration of the weakly basic anion exchange resin 11 as acidic electrolyzed water and alkaline electrolyzed water, respectively. At this time, the hardness components contained in the acidic electrolyzed water are reduced compared to the case where city water or no separation unit 14 is provided. That is, by separating the precipitates by the separation unit 14, the hardness of the acidic electrolyzed water is reduced, so that the hardness components flowing into the softening tank 3 can be reduced, and a decrease in the regeneration efficiency of the weakly acidic cation exchange resin 10 can be suppressed.

[0038] Note that "the hardness components react" includes not only the case where all the hardness components react, but also the state in which components that do not react or components that do not exceed the solubility product are included.

[0039] The form of the separation unit 14 is not limited as long as it can separate the precipitate generated by the reaction between the hardness components and the alkaline electrolyzed water. For example, there are forms using a cartridge-type filter, a filtration layer using granular filter media, a cyclone-type solid-liquid separator, a hollow fiber membrane, etc.

[0040] As a commonly used means for the form of the separation unit 14, a cartridge-type filter can be mentioned. As the cartridge-type filter, a deep filtration type such as a wound filter, a surface filtration type such as a pleat filter and a membrane filter, or a combination thereof can be used.

[0041] The wound filter corresponds to a particle size of 1 to 150 micrometers and is mainly used as a pre-filter. Although there are pleat filters and membrane filters corresponding to a wide range of particle sizes of about 0.03 to 100 micrometers, in particular, when implementing the present invention, those with an accuracy of about 0.5 to 1.5 micrometers are preferably used to capture the hardness components deposited in the regeneration process described later. Since alkaline electrolyzed water flows through the separation unit 14 in the regeneration process described later and acidic electrolyzed water flows through it in the washing process, the material of the cartridge-type filter is preferably a material highly resistant to acids and alkalis (for example, polypropylene).

[0042] The granular filter media used in the filtration layer aims to capture and remove hardness components. However, depending on the presence of particles with a surface potential that adsorbs to the granular filter media, ions in the raw water, etc., particles with a particle size of about 1 to 10 micrometers or colority can also be removed. As the granular filter media, filter sand, pellet-shaped fiber filter media, etc., filter media suitable for the object to be removed can be used. The material of the granular filter media may be, for example, sand, anthracite, garnet, ceramics, granular activated carbon, iron oxyhydroxide, manganese sand, etc., as long as it has a hardness that settles in water and is difficult to deform under pressure. The particle size may be, for example, 0.3 to 5.0 millimeters, and those with a uniformity coefficient of 1.2 to 2.0 are preferably used.

[0043] In addition, the multi-layer filtration method of mixing and using multiple types of filter media with different specific gravities is a method of stacking particles of different sizes in order from small to large as the layer for filtration. In the multi-layer filtration method, it is common to mix particles with a large specific gravity and a small size and particles with a small specific gravity and a large size to form a multi-layer structure. The multi-layer filtration method is preferable because it has advantages such as higher filtration efficiency per unit volume and lower head loss compared to using a single type of filter media. As the granular filter media, for example, 0.3 millimeter of garnet, 0.6 millimeter of sand, and 1.0 millimeter of anthracite are mixed and used in a ratio of 2:1:1, but it is preferable to adjust the mixing ratio or particle size according to the particle characteristics of the turbidity.

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

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

[0046] Also, each of the 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 the selection valve 40 is connected to be communicable with a control unit 17, which will be described later, wirelessly or by wire.

[0047] (Drain port) The drain port 16 discharges the acidic soft water that has passed through the separation unit 14 outside the apparatus during the cleaning of the separation unit 14 (during the separation unit cleaning process) described later, and discharges the electrolyzed water (acidic electrolyzed water and alkaline electrolyzed water) and acidic soft water remaining in each flow path outside the apparatus during the drainage process.

[0048] More specifically, during the separation unit cleaning process, the drain port 16 discharges the water that has passed through the flow path 7, the softening tank 3, the flow path 8, the flow path 29, the on-off valve 41, the separation unit 14, the selection valve 40, and the drainage flow path 26, and discharges the water containing the hardness components generated by the dissolution of the precipitates in the separation unit 14 outside the apparatus.

[0049] Also, during the drainage process, the drain port 16 discharges the water remaining in the circulation flow path 20 and the separation unit cleaning flow path 27 (for example, acidic electrolyzed water, alkaline electrolyzed water, and acidic soft water), the water sent from the electrolysis tank 12, and the water flowing through the second supply flow path 23 and the drainage flow path 26 (such as the alkaline electrolyzed water remaining in the flow path) outside the apparatus.

[0050] (Control unit) The control unit 17 controls the regeneration processes of the weakly acidic cation exchange resin 10 in the softening tank 3 and the weakly basic anion exchange resin 11 in the neutralization tank 4. Further, the control unit 17 controls the separation unit cleaning process for cleaning the separation unit 14 with acidic soft water. Further, the control unit 17 controls the drainage process for draining the water remaining in each flow path. Further, the control unit 17 controls the softening process for softening raw water containing hardness components. Further, the control unit 17 controls the operation of the on-off valve 41 and controls the flow direction and flow rate of the acidic soft water flowing out from the softening tank 3. Further, the control unit 17 controls the operation of the selection valve 40 and controls the flow direction of the water flowing out from the separation unit 14. Furthermore, the control unit 17 controls the switching of the regeneration process, the separation unit cleaning process, the drainage process, and the softening process of the water softening apparatus 1. At this time, the control unit 17 controls the operations of the electrode 13, the water supply pump 19, a plurality of on-off valves (on-off valves 31, 32, 34 to 39, and on-off valve 41), and the selection valve 40, and executes the switching and respective processes of the regeneration process, the separation unit cleaning process, the drainage process, and the softening process.

[0051] (Flow path) Next, with reference to FIG. 2, the circulation flow path 20 formed during the regeneration process of the water softening apparatus 1 will be described. FIG. 2 is a configuration diagram showing the circulation flow path 20 of the water softening apparatus 1.

[0052] Although the description is repetitive, as shown in FIG. 2, in the water softening apparatus 1, the electrolytic cell 12 and the water storage tank 15 constituting the regeneration apparatus 6 are connected in communication by the water supply flow path 25. Further, the electrolytic cell 12 and the water storage tank 15 are respectively connected in communication with the flow paths 7, 8, and 9 from the inlet 2 to the water intake 5 by the first supply flow path 21, the first recovery flow path 22, the second supply flow path 23, and the second recovery flow path 24. And in the regeneration apparatus 6, the circulation flow path 20 is constituted by the combination of each flow path.

[0053] The first supply flow path 21 is a flow path for supplying acidic electrolyzed water from the electrolytic cell 12 to the softening tank 3, and an on-off valve 35 is installed in that flow path. That is, the water softening apparatus 1 includes the first supply flow path 21 that can draw out acidic electrolyzed water from the electrolytic cell 12 and supply it to the upstream side of the softening tank 3.

[0054] And the first recovery channel 22 is a channel for recovering the water containing hardness components that has passed through the water softening tank 3 to the water storage tank 15, and an on-off valve 36 is installed in that channel. That is, the water softening device 1 includes a first recovery channel 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.

[0055] The second supply channel 23 is a channel for supplying alkaline electrolyzed water from the electrolysis tank 12 to the neutralization tank 4 via the separation unit 14 during the regeneration process described later, and a separation unit 14, a selection valve 40, and an on-off valve 37 are installed in that channel. That is, the water softening device 1 includes a second supply channel 23 that separates precipitates derived from hardness components contained in the alkaline electrolyzed water drawn from the electrolysis tank 12 by the separation unit 14 and enables the alkaline electrolyzed water from which the precipitates have been separated to be sent to the upstream side of the neutralization tank 4. Note that the second supply channel 23 is connected to the channel 8 on the downstream side of the first recovery channel 22. This is to suppress the mixing of the acidic electrolyzed water discharged from the water softening tank 3 and the alkaline electrolyzed water sent from the electrolysis tank 12 during the regeneration process described later. That is, the channel 8 is connected to the first recovery channel 22 and the second supply channel 23 in order from the upstream side.

[0056] And the second recovery channel 24 is a channel for recovering the water that has passed through the neutralization tank 4 to the water storage tank 15, and an on-off valve 38 is installed in that channel. That is, the water softening device 1 includes a second recovery channel 24 that enables the upstream side of the water storage tank 15 to be connected to the downstream side of the neutralization tank 4.

[0057] The circulation channel 20 includes a first circulation channel 20a through which the water sent from the water storage tank 15 by the water supply pump 19 flows through the water softening tank 3, and a second circulation channel 20b through which the water sent from the water storage tank 15 by the water supply pump 19 flows through the neutralization tank 4.

[0058] As shown in Fig. 2 (white arrow), the first circulation flow path 20a is a flow path through which the water sent out from the water storage tank 15 by the water supply pump 19 circulates through the electrolytic cell 12 and the water softening tank 3 and then returns to the water storage tank 15. More specifically, in the first circulation flow path 20a, the water sent out from the water storage tank 15 by the water supply pump 19 circulates in the order of the water supply flow path 25, the electrolytic cell 12, the first supply flow path 21, the on-off valve 35, the water softening tank 3, the first recovery flow path 22, the on-off valve 36, and the water storage tank 15 and then circulates.

[0059] As shown in Fig. 2 (black arrow), the second circulation flow path 20b is a flow path through which the water sent out from the water storage tank 15 by the water supply pump 19 circulates through the electrolytic cell 12 and the neutralization tank 4 and then returns to the water storage tank 15. More specifically, in the second circulation flow path 20b, the water sent out from the water storage tank 15 by the water supply pump 19 circulates in the order of the water supply flow path 25, the electrolytic cell 12, the second supply flow path 23, the separation unit 14, the selection valve 40, the on-off valve 37, the neutralization tank 4, the second recovery flow path 24, the on-off valve 38, and the water storage tank 15 and then circulates.

[0060] Here, in order to circulate water in the circulation flow path 20, an on-off valve 31 is installed on the downstream side of the inlet 2 in the flow path 7. By closing the on-off valve 31 and opening the on-off valve 35, the first supply flow path 21 is connected in communication to the upstream side of the water softening tank 3. As a result, the acidic electrolyzed water from the electrolytic cell 12 can be supplied to the water softening tank 3.

[0061] Also, an on-off valve 32 is installed on the downstream side of the first recovery flow path 22 and the flow path 29 and on the upstream side of the second supply flow path 23 in the flow path 8. 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 in communication to the downstream side of the water softening tank 3. As a result, in the water softening device 1, the water (acidic electrolyzed water containing hardness components) that has passed through the water softening tank 3 can be recovered to the water storage tank 15.

[0062] Further, 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 neutralization tank 4 direction (the direction flowing from the separation unit 14 to the neutralization tank 4), the second supply flow path 23 is communicatively connected to the upstream side of the neutralization tank 4. As a result, in the water softening apparatus 1, the alkaline electrolyzed water from the electrolytic cell 12 can be circulated to the separation unit 14 and supplied to the neutralization tank 4.

[0063] Further, an on-off valve 34 is installed in the flow path 9 on the downstream side 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 communicatively connected to the downstream side of the neutralization tank 4. As a result, the water (alkaline electrolyzed water containing anions) that has passed through the second recovery flow path 24 can be recovered to the water storage tank 15.

[0064] Further, 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.

[0065] Further, an on-off valve 39 is installed in the water supply flow path 25 on the downstream side of the water storage tank 15 (at a position between the water storage tank 15 and the water supply pump 19). By closing the on-off valve 39, water can be stored in the water storage tank 15. On the other hand, by opening the on-off valve 39, water can be supplied to the water supply flow path 25.

[0066] Further, 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, the flow path state in which the 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 the flow path state in which the water that has passed through the separation unit 14 is discharged outside the apparatus through the drain port 16 via the drain flow path 26 described later can be achieved. In the flow path state in which the water that has passed through the separation unit 14 is discharged outside the apparatus through the drain port 16, the acidic soft water used for cleaning the separation unit 14 during the separation unit cleaning process, or the drainage of the electrolyzed water remaining in the circulation flow path 20 and the acidic soft water remaining in the separation unit cleaning flow path 27 during the drainage process is performed.

[0067] Next, with reference to FIG. 3, the separation unit cleaning channel 27 formed during the separation unit cleaning process of the water softening device 1 will be described. FIG. 3 is a configuration diagram showing the separation unit cleaning channel 27 of the water softening device 1.

[0068] As shown in FIG. 3, the separation unit cleaning channel 27 is composed of channels connecting the inlet 2, the water softening tank 3, the separation unit 14, and the drain port 16. The water softening tank 3 is communicatively connected to the inlet 2 through the channel 7. The water softening tank 3 is also communicatively connected to the separation unit 14 through the channel 8, the channel 29, and the second supply channel 23. The separation unit 14 is communicatively connected to the drain port 16 through the second supply channel 23 and a drain channel 26 described later. A selection valve 40 is provided at the connection part between the second supply channel 23 and the drain channel 26.

[0069] The channel 29 is a channel for supplying the acidic softened water from the water softening tank 3 to the separation unit 14. The channel 29 is communicatively connected to the channel 8 between the water softening tank 3 and the second supply channel 23. The channel 29 is also communicatively connected to the second supply channel 23 between the electrolytic cell 12 and the separation unit 14. An on-off valve 41 is provided in the channel 29. That is, the water softening device 1 includes the channel 29 for supplying the acidic softened water softened by the water softening tank 3 to the separation unit 14 for the separation unit cleaning process.

[0070] The drain channel 26 is a channel for discharging water from the selection valve 40 to the drain port 16. The drain channel 26 is communicatively connected to the second supply channel 23 between the separation unit 14 and the neutralization tank 4. A selection valve 40 is provided in the drain channel 26. That is, the water softening device 1 includes the drain channel 26 that can draw water from the selection valve 40 to the drain port 16 and discharge it outside the device.

[0071] As shown in FIG. 3 (diagonal arrow), in the separation unit cleaning channel 27, the water introduced from the inlet 2 flows through the channel 7 and the water softening tank 3 in sequence. After being made into acidic softened water in the water softening tank 3, it then flows through the channel 8, the channel 29, the second supply channel 23, and the separation unit 14 in sequence, is used for the separation unit cleaning process, flows through the selection valve 40 and the drain channel 26, and is discharged outside the device from the drain port 16.

[0072] (Softening treatment, regeneration treatment, separation unit cleaning treatment, and wastewater treatment) Next, with reference to FIG. 4, the regeneration treatment, separation unit cleaning treatment, wastewater treatment, and softening treatment of the water softening apparatus 1 starting from the regeneration treatment will be described. FIG. 5 is a diagram showing the state during the operation of the water softening apparatus 1.

[0073] In the regeneration treatment, separation unit cleaning treatment, wastewater treatment, and softening treatment, as shown in FIG. 4, the control unit 17 controls the on-off valves 31, 32, 34 to 39, the selection valve 40, the on-off valve 41, the electrodes 13 of the electrolytic cell 12, and the water supply pump 19 to switch to their respective flow states. Note that the control unit 17 has a computer system having a processor and a memory. Then, by the processor executing the program stored in the memory, the computer system functions as the control unit. The program executed by the processor is assumed to be pre-recorded in the memory of the computer system here, but it may be recorded and provided on a non-temporary recording medium such as a memory card, or may be provided through an electric communication line such as the Internet.

[0074] Here, "ON" in FIG. 4 indicates the state where the corresponding on-off valve is "open", the state where the electrode 13 is energized, and the state where the water supply pump 19 is operating, respectively. The blank spaces indicate the state where the corresponding on-off valve is "closed", the state where the electrode 13 is not energized, and the state where the water supply pump 19 is stopped, respectively. Also, the notation of the selection valve 40 in FIG. 4 indicates the state where the flow path is opened to the component (neutralization tank 4 or drain port 16) corresponding to the number (symbol). The selection valve 40 is normally in the state where the flow path is opened to the neutralization tank 4, but is shown as a blank space when not related to other processes.

[0075] (Regeneration treatment) First, the operation during the regeneration treatment by the regeneration device 6 of the water softening apparatus 1 will be described in order with reference to the columns of "water injection" and "regeneration" in FIG. 4.

[0076] In the water softening device 1, the water softening tank 3 filled with the weakly acidic cation exchange resin 10 will have its cation exchange capacity decreased or lost if used continuously. That is, after all the hydrogen ions, which are the functional groups of the cation exchange resin, are exchanged with calcium ions or magnesium ions, which are hardness components, ion exchange can no longer occur. In such a state, the hardness components will be contained in the treated water. Therefore, in the water softening device 1, it is necessary to perform a regeneration process on the water softening tank 3 and the neutralization tank 4 by the regeneration device 6.

[0077] Therefore, in the water softening device 1, once every predetermined period (for example, one day (24 hours)), the control unit 17 identifies the time zone during which the regeneration process is possible and executes the regeneration process.

[0078] First, as shown in FIG. 4, when injecting water, the on-off valve 31 and the on-off valve 36 are opened. Thereby, the water softening device 1 introduces raw water from the inlet 2 through the water softening tank 3 to the water storage tank 15 by the pressure of the municipal water. At this time, the on-off valve 32, the on-off valve 34, the on-off valve 35, the on-off valve 37 to the on-off valve 39, and the on-off valve 41 are closed. Also, the selection valve 40 connects the flow path in the direction in which the water flowing through the separation unit 14 flows into 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 during regeneration.

[0079] Next, during regeneration, the on-off valve 31, the on-off valve 32, the on-off valve 34, and the on-off valve 41 are closed, the on-off valve 35 to the on-off valve 39 are opened, and the water flow direction of the selection valve 40 is set to the neutralization tank 4 direction (the direction from the separation unit 14 to the neutralization tank 4). Then, as shown in FIG. 2, the first circulation flow path 20a and the second circulation flow path 20b are respectively formed.

[0080] Then, when the electrode 13 of the electrolytic cell 12 and the water pump 19 are operated, the water stored in the water storage tank 15 will circulate through each of the first circulation flow path 20a and the second circulation flow path 20b.

[0081] At this time, the acidic electrolyzed water generated in the electrolytic cell 12 is sent into the softening tank 3 through the first supply channel 21 and flows through the weakly acidic cation exchange resin 10 inside. 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. As a result, the weakly acidic cation exchange resin 10 is regenerated. Then, the acidic electrolyzed water that has flowed through the weakly acidic cation exchange resin 10 contains cations and flows into the first recovery channel 22. That is, the acidic electrolyzed water containing cations that has flowed through the weakly acidic cation exchange resin 10 is recovered into the water storage tank 15 through the first recovery channel 22.

[0082] On the other hand, the alkaline electrolyzed water generated in the electrolytic cell 12 is sent into the neutralization tank 4 through the second supply channel 23 and the separation unit 14 and flows through the weakly basic anion exchange resin 11 inside. That is, by flowing the alkaline electrolyzed water through the weakly basic anion exchange resin 11, the anions adsorbed on the weakly basic anion exchange resin 11 undergo an ion exchange reaction with the hydroxide ions contained in the alkaline electrolyzed water. As a result, the weakly basic anion exchange resin 11 is regenerated. Then, the alkaline electrolyzed water that has flowed through the weakly basic anion exchange resin 11 contains anions and flows into the second recovery channel 24. That is, the alkaline electrolyzed water containing anions that has flowed through the weakly basic anion exchange resin 11 is recovered into the water storage tank 15 through the second recovery channel 24.

[0083] And in the water storage tank 15, the acidic electrolyzed water containing cations recovered from the softening tank 3 and the alkaline electrolyzed water containing anions recovered from the neutralization tank 4 are mixed and neutralized.

[0084] At this time, by mixing acidic electrolyzed water containing cations (hardness components) and alkaline electrolyzed water containing anions, the hardness components react with the hydroxide ions contained in the alkaline electrolyzed water to form precipitates. However, at least in the initial stage of the regeneration process, the amount of hydroxide ions contained in the alkaline electrolyzed water flowing into the neutralization tank 4 is smaller than the amount of hardness components discharged from the water softening tank 3, so the state is such that precipitates are less likely to form. For this reason, the hardness components contained in the neutralized electrolyzed water are directly sent to the electrolysis tank 12.

[0085] After that, the electrolyzed water mixed in the water storage tank 15 is passed through the water supply channel 25 and passed through the electrolysis tank 12 again. Then, the passed water is electrolyzed again in the electrolysis tank 12.

[0086] As described above, electrolysis of water is carried out in the electrolysis tank 12. Near the cathode, a large amount of hydroxide ions are generated by electrolysis, so the state is such that precipitates are likely to form. That is, the hardness components (for example, calcium ions, magnesium ions) contained in the water supplied from the water storage tank 15 move to the cathode side and react with the hydroxide ions to form precipitates. Then, the alkaline electrolyzed water containing the precipitates is sent to the second supply channel 23 and flows into the separation unit 14.

[0087] In the separation unit 14, the precipitates contained in the alkaline electrolyzed water are separated, and alkaline electrolyzed water (treated water) from which the hardness components have been removed can be obtained. Then, the acidic electrolyzed water electrolyzed again in the electrolysis tank 12 and the alkaline electrolyzed water electrolyzed again in the electrolysis tank 12 and from which the precipitates have been separated by the separation unit 14 are respectively used for the regeneration of the weakly acidic cation exchange resin 10 and the regeneration of the weakly basic anion exchange resin 11.

[0088] Here, as a problem that occurs in the neutralization tank of a conventional water softening device, during the regeneration process, precipitates generated by the reaction of the hardness components discharged from the water softening tank and the alkaline electrolyzed water in the electrolytic cell flow into the neutralization tank and accumulate inside the neutralization tank. That is, when the water softening treatment is restarted with the precipitates accumulated in the neutralization tank, it reacts with the hydrogen ions discharged from the water softening tank and becomes hardness components, resulting in a decrease in the water softening performance. However, in the present embodiment, by separating the precipitates generated in the electrolytic cell 12 by the separation unit 14, it is possible to suppress the accumulation of precipitates caused by hardness components inside the neutralization tank 4.

[0089] After that, in the water softening device 1, when the regeneration process is completed, the operation of the electrode 13 is stopped. Then, the on-off valves 35 to 39 are closed, and the on-off valves 31 and 41 are opened. Further, the water flow direction of the selection valve 40 is switched from the neutralization tank 4 direction (the direction flowing from the separation unit 14 to the neutralization tank 4) to the drain port 16 direction (the direction flowing from the separation unit 14 to the drain port 16). Thereby, the process shifts from the regeneration process to the separation unit cleaning process.

[0090] (Separation unit cleaning process) When the regeneration process is completed, the water softening device 1 shifts to the separation unit cleaning process. Here, the separation unit cleaning process is a process for cleaning the separation unit 14, in which the acidic soft water generated in the water softening tank 3 is circulated through the separation unit 14 to dissolve the precipitates caused by the hardness components separated in the separation unit 14.

[0091] Next, the operation during the cleaning process by the water softening device 1 will be described with reference to the "During separation unit cleaning" column in FIG. 4.

[0092] In the water softening device 1, as shown in FIG. 4, in the separation unit cleaning process, the on-off valves 31 and 41 are opened, and the selection valve 40 is switched so that the flow path state allows water to flow from the separation unit 14 to the drain flow path 26. Thereby, in the water softening device 1, the separation unit cleaning flow path 27 is formed, and the separation unit 14 can be cleaned. At this time, the on-off valves 32 and 34 to 39 are closed.

[0093] Specifically, in the separation unit cleaning process, as shown in FIG. 3, due to the pressure of city water, the raw water to be supplied flows from the inlet 2 through the flow path 7 and is supplied to the water softening tank 3. Then, the raw water supplied to the water softening tank 3 flows through the weakly acidic cation exchange resin 10 provided in the water softening tank 3. At this time, the cations, which are the hardness components in the raw water, are adsorbed by the action of the weakly acidic cation exchange resin 10, and hydrogen ions are released (ion exchange occurs). And when the cations are removed from the raw water, the raw water is softened. At this time, due to the release of hydrogen ions, the water flowing out of the water softening tank 3 becomes acidic. That is, the raw water flowing into the water softening tank 3 is sent out from the water softening tank 3 as acidic soft water.

[0094] Next, since the on-off valve 41 is open and the on-off valves 32 and 36 are closed, the acidic soft 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 flows into the separation unit 14. By allowing the acidic soft water to flow into the separation unit 14, the precipitate caused by the hardness components captured in the separation unit 14 reacts with the acidic soft water. As a result, the precipitate caused by the hardness components dissolves and becomes hardness components and is contained in the acidic soft water.

[0095] And since the water passing direction of the selection valve 40 is set to the drain port 16 direction (the direction flowing from the separation unit 14 to the drain port 16), the acidic soft water flowing through the separation unit 14 flows through the drain flow path 26 and is discharged outside the apparatus from the drain port 16. That is, by allowing the acidic soft water to flow through the separation unit 14 and discharging the flowing acidic soft water, the separation unit 14 can be cleaned and the hardness components can be discharged outside the apparatus. Thereby, the precipitate captured by the separation unit 14 can be dissolved and removed, and the separation unit 14 can be cleaned, so that the decrease in the water flow rate due to the clogging of the separation unit 14 can be reduced.

[0096] And in the water softening apparatus 1, when the separation unit cleaning process is completed, the on-off valves 31 and 41 are closed, the on-off valves 35 to 39 are opened, and the water supply pump 19 is started to shift to the drainage process.

[0097] Note that the completion of the separation unit cleaning process is set to occur after a certain period of time (e.g., 1 hour) has elapsed since the start of the separation unit cleaning process. Here, the certain period of time is the time required to dissolve the precipitates captured by the separation unit 14, and is set based on the evaluation results of the cleaning experiments conducted in advance.

[0098] (Wastewater treatment) In the water softening device 1, when the separation unit cleaning process is completed, it shifts to the wastewater treatment. Here, the wastewater treatment is a process of discharging the raw water, acidic electrolyzed water, alkaline electrolyzed water, and acidic softened water remaining in the circulation channel 20.

[0099] Next, the operation during the wastewater treatment by the water softening device 1 will be described with reference to the "During wastewater discharge" column in FIG. 4.

[0100] In the water softening device 1, as shown in FIG. 4, during the wastewater treatment (during wastewater discharge), the on-off valves 31, 32, 34, and 41 are closed, and the on-off valves 35 to 39 are opened. Also, the water flow direction of the selection valve 40 is set to the wastewater outlet 16 direction (the direction of flow from the separation unit 14 to the wastewater outlet 16). As a result, the inflow of municipal water from the inlet 2 is stopped, and the acidic electrolyzed water remaining in the path from the electrolytic cell 12 to the water storage tank 15 via the first supply channel 21, the water softening tank 3, and the first recovery channel 22, and the alkaline electrolyzed water remaining in the path from the separation unit 14 to the water storage tank 15 via the second supply channel 23, the neutralization tank 4, and the second recovery channel 24 can be made to flow into the water storage tank 15.

[0101] Next, the water supply pump 19 is started, the on-off valve 39 is opened, and the flow direction of the selection valve 40 is switched to the wastewater outlet 16 direction. As a result, the electrolyzed water remaining in the path from the inside of the water storage tank 15 to the electrolytic cell 12 via the water supply channel 25, the electrolyzed water remaining in the path from the inside of the electrolytic cell 12 to the wastewater outlet 16 via the second supply channel 23 and the wastewater channel 26, and the acidic softened water remaining in the separation unit cleaning channel 27 can be discharged outside the device. At this time, the electrode 13 has stopped operating.

[0102] Then, in the water softening device 1, when the wastewater treatment is completed, the operation of the water supply 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 neutralization tank 4 direction (the direction flowing from the separation unit 14 to the neutralization tank 4), thereby shifting to the water softening treatment.

[0103] Note that the end of the wastewater treatment is defined as when a certain period of time (for example, 1 minute) has elapsed since the start of the wastewater treatment.

[0104] (Water Softening Treatment) When the wastewater treatment is completed, the water softening device 1 shifts to the water softening treatment.

[0105] The operation during the water softening treatment by the water softening device 1 will be described with reference to the "During Water Softening" column in FIG. 4.

[0106] In the water softening device 1, as shown in FIG. 4, during the water softening treatment, with the on-off valves 31 and 32 open, the on-off valve 34 provided at the water intake 5 is opened. As a result, in the water softening device 1, municipal water (raw water containing hardness components) from the outside flows through the water softening tank 3 and the neutralization tank 4, so that the water softened (neutral soft water) can be taken out from the water intake 5.

[0107] Specifically, in the softening treatment, due to the pressure of the municipal water, the supplied raw water is supplied from the inlet 2 through the flow path 7 to the softening tank 3. Then, the raw water supplied to the softening tank 3 flows through the weakly acidic cation exchange resin 10 provided in the softening tank 3. At this time, the cations, which are the hardness components in the raw water, are adsorbed by the action of the weakly acidic cation exchange resin 10, and hydrogen ions are released (ion exchange occurs). And, as the cations are removed from the raw water, the raw water is softened. The softened water further proceeds to the neutralization tank 4 through the flow path 8. In the neutralization tank 4, the hydrogen ions contained in the softened water are adsorbed by the action of the weakly basic anion exchange resin 11. That is, since the hydrogen ions are removed from the treated soft water, the decreased pH rises, and it becomes neutral water softened as domestic water, and can be taken out from the water intake 5 through the flow path 9. At this time, all of the on-off valves 35 to 39 are in a closed state. Also, the operation of the electrodes 13 of the electrolytic cell 12 and the water supply pump 19 is also stopped.

[0108] And, in the softening device 1, when the time zone specified by the control unit 17 is reached or when the softening treatment exceeds a certain time, the softening treatment is stopped and the above-described regeneration treatment is executed.

[0109] As described above, in the softening device 1, the regeneration treatment, the separation unit cleaning treatment, the drainage treatment, and the softening treatment are repeatedly executed. And, the softening device 1 supplies the municipal water (raw water containing hardness components) as neutral soft water that can be used as domestic water.

[0110] As described above, according to the softening device 1 according to the first embodiment, the following effects can be enjoyed.

[0111] (1) The water softening device 1 includes a water softening tank 3, a neutralization tank 4, an electrolytic cell 12, and a separation unit 14. The water softening tank 3 softens raw water containing hardness components and chloride ions with a weakly acidic cation exchange resin 10. The neutralization tank 4 neutralizes the pH of the softened water that has passed through the water softening tank 3 with a weakly basic anion exchange resin 11. The electrolytic cell 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 separation unit 14 is provided in a flow path communicating the electrolytic cell 12 and the neutralization tank 4, and separates precipitates resulting from the hardness components contained in the water introduced into the electrolytic cell 12. Then, the water softening device 1 performs a separation unit cleaning process of discharging the acidic softened water that has flowed through the water softening tank 3 to the outside of the device after flowing it through the separation unit 14.

[0112] Thereby, using the acidic softened water softened by the water softening tank 3, the precipitates separated by the separation unit 14 can be dissolved, and the separation unit 14 can be cleaned. Therefore, the separation unit 14 can be surely cleaned, and the water softening device 1 that can be used over a long period can be obtained.

[0113] (2) In the water softening device 1, the end of the separation unit cleaning process is set to be after a certain period from the start of the separation unit cleaning process. Thereby, the cleaning process of the separation unit 14 can be completed in a certain period. Therefore, insufficient cleaning of the separation unit 14 or excessive use of acidic softened water can be suppressed.

[0114] (Embodiment 2) Next, with reference to FIG. 5, the water softening device 1a according to Embodiment 2 of the present invention will be described. FIG. 5 is a configuration diagram showing a flow path when the water softening process and the separation unit cleaning process of the water softening device 1a according to Embodiment 2 are performed in parallel.

[0115] The water softening device 1a according to Embodiment 2 differs from Embodiment 1 in that it is configured to perform the separation unit cleaning process and the water softening process in parallel. The configuration of the water softening device 1a other than this is the same as that of the water softening device 1 according to Embodiment 1. Hereinafter, the content already described in Embodiment 1 will be omitted as appropriate, and the points different from Embodiment 1 will be mainly described.

[0116] As shown in FIG. 5, the water softening device 1a is configured to perform the separation unit cleaning process by the separation unit cleaning flow path 27a and the water softening process by the raw water softening flow path 28 in parallel. More specifically, in the water softening device 1a, after the regeneration process is completed, the drainage process is performed, and then, the separation unit cleaning process is performed during the period when the water softening process is being performed.

[0117] (Flow Path and On-Off Valve) As shown in FIG. 5, the separation unit cleaning flow path 27a is constituted by the flow paths connecting the inlet 2, the water softening tank 3, the separation unit 14, and the drain port 16. The water softening tank 3 is connected in communication with the inlet 2 by the flow path 7. Further, the water softening tank 3 is connected in communication with the separation unit 14 by the flow path 8, the flow path 29, and the second supply flow path 23. The separation unit 14 is connected in communication with the drain port 16 by the second supply flow path 23 and the drainage flow path 26. A selection valve 40 is provided at the connection portion between the second supply flow path 23 and the drainage flow path 26. Also, an on-off valve 41a is provided in the flow path 29.

[0118] As shown in FIG. 5 (diagonal arrow), in the separation unit cleaning flow path 27a, the water introduced from the inlet 2 flows in the order of the flow path 7 and the water softening tank 3, is made into acidic soft water in the water softening tank 3, and then flows in the order of the flow path 8, the flow path 29, the second supply flow path 23, and the separation unit 14, is subjected to the separation unit cleaning process, flows through the selection valve 40 and the drainage flow path 26, and is discharged out of the device from the drain port 16.

[0119] The on-off valve 41a is provided in the flow path 29 and switches between the "open" state and the "closed" state in the flow path 29. Further, the on-off valve 41a is a valve that can not only switch between "open" and "closed", but also adjust the degree of opening with respect to the flow path. By adjusting the degree of opening of the on-off valve 41a, the flow rate of the acidic soft water supplied to the flow path 29 can be adjusted according to the state of the separation unit cleaning process.

[0120] As shown in FIG. 5, the raw water softening flow path 28 is composed of flow paths connecting the inlet 2, the softening tank 3, the neutralization tank 4, and the water intake 5. The softening tank 3 is connected in communication with the inlet 2 through the flow path 7. Further, the softening tank 3 is connected in communication with the neutralization tank 4 through the flow path 8. The neutralization tank 4 is connected in communication with the water intake 5 through the flow path 9.

[0121] The raw water softening flow path 28 is a flow path that enables the use of municipal water (raw water containing hardness components) introduced from the outside as neutral soft water through a softening process. More specifically, as shown in FIG. 5 (black arrow and white arrow), the water introduced from the inlet 2 flows through the flow path 7 and the softening tank 3 in this order, becomes acidic soft water in the softening tank 3, then flows into the neutralization tank 4, is neutralized, and flows out to the outside from the water intake 5.

[0122] (Regeneration process, drainage process, separation unit cleaning process, and softening process) In the softening device 1a, when the regeneration process is completed, the operation of the electrode 13 is stopped. Further, by switching the water flow direction of the selection valve 40 from the neutralization tank 4 direction (the direction of flowing from the separation unit 14 to the neutralization tank 4) to the drain port 16 direction (the direction of flowing from the separation unit 14 to the drain port 16), the process proceeds to the drainage process.

[0123] Also, in the softening device 1a, when the drainage process is completed, the operation of the water supply pump 19 is stopped. Further, the on-off valves 35 to 39 are closed, the on-off valves 31, 32, 34, and 41a are opened, and the water flow direction of the selection valve 40 is set to the drain port 16 direction (the direction of flowing from the separation unit 14 to the drain port 16), so that the process proceeds to the softening process (and the separation unit cleaning process).

[0124] In the water softening device 1a, in the water softening process, with the on-off valves 31 and 32 open, the on-off valve 34 provided at the water intake 5 is opened. As a result, as shown in FIG. 5, in the water softening device 1, a raw water softening flow path 28 is formed, and municipal water (raw water containing hardness components) from the outside flows through the water softening tank 3 and the neutralization tank 4, so that the softened water (neutral soft water) can be taken out from the water intake 5.

[0125] Here, the on-off valve 41a provided in the flow path 29 is opened to a predetermined opening degree. This is to enable a part (for example, 20%) of the acidic soft water flowing out of the water softening tank 3 to be sent to the separation unit 14. As a result, a separation unit cleaning flow path 27a is formed. At this time, the remaining acidic soft water (for example, 80%) that is not sent to the separation unit cleaning flow path 27a is sent to the neutralization tank 4. With such a configuration, it becomes possible to perform the water softening process and the separation unit cleaning process in parallel. More specifically, after the regeneration process is completed, the drainage process is performed, and then the separation unit cleaning process can be performed during the period when the water softening process is being carried out. At this time, the on-off valves 35 to 39 are all in a closed state. Also, the operation of the electrodes 13 of the electrolytic cell 12 and the water supply pump 19 is stopped. Note that the water softening device 1a is configured to start the separation unit cleaning process and the water softening process simultaneously.

[0126] Then, in the water softening device 1a, when the separation unit cleaning process is completed, the on-off valve 41a is closed. As a result, the acidic soft water sent out from the water softening tank 3 can be used for the water softening process without being used for the separation unit cleaning process. At this time, the water flow direction of the selection valve 40 is set in the direction of the neutralization tank 4 (the direction of flowing from the separation unit 14 to the neutralization tank 4).

[0127] Note that the end of the separation unit cleaning process is set to be when a certain time (for example, 1 hour) has elapsed since the start of the separation unit cleaning process. Here, the certain time is a time set based on the evaluation results of the cleaning experiment performed in advance as the time required to dissolve the precipitate captured by the separation unit 14.

[0128] Then, in the water softening device 1a, when the time zone specified by the control unit 17 is reached or when the water softening treatment exceeds a certain time, the water softening treatment is stopped and the regeneration treatment is executed.

[0129] As described above, in the water softening device 1a, the regeneration treatment, the drainage treatment, the separation unit cleaning treatment, and the water softening treatment are repeatedly executed. And the water softening device 1a supplies municipal water (raw water containing hardness components) as neutral soft water that can be used as domestic water.

[0130] As described above, according to the water softening device 1a according to the second embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be enjoyed.

[0131] (3) During the period when the water softening device 1 performs the water softening treatment of the raw water by the water softening tank 3 and the neutralization tank 4, a part of the acidic soft water that has flowed through the water softening tank 3 is made to flow through the separation unit 14. Thereby, the cleaning treatment of the separation unit 14 can be performed in parallel with the water softening treatment. Therefore, compared with the case where the water softening treatment is performed after the separation unit cleaning treatment, the water softening treatment can be executed for a longer time.

[0132] (4) In the water softening device 1, when the separation unit cleaning treatment is completed, the supply of acidic soft water to the separation unit 14 is configured to be stopped. Thereby, the supply of acidic soft water to the separation unit 14 exceeding the amount required for the separation unit cleaning treatment can be suppressed. Therefore, the separation unit cleaning treatment can be completed without using excessive acidic soft water.

[0133] (Embodiment 3) Next, with reference to FIGS. 6 to 9, the water softening device 1b according to the third embodiment of the present invention will be described. FIG. 6 is a conceptual diagram showing the configuration of the water softening device 1b according to the third embodiment of the present invention. FIG. 7 is a configuration diagram showing the circulation flow path 20c of the water softening device 1b according to the third embodiment. FIG. 8 is a configuration diagram showing the separation unit cleaning flow path 27b of the water softening device 1b according to the third embodiment. FIG. 9 is a diagram showing the state during the operation of the water softening device 1b according to the third embodiment.

[0134] The softening device 1b according to Embodiment 3 is different from Embodiment 1 in that it is configured to perform backwashing of the separation unit 14 during cleaning of the separation unit. The configuration of the softening device 1b other than this is the same as that of the softening device 1 according to Embodiment 1. Hereinafter, the contents already described in Embodiment 1 will be appropriately omitted from further description, and the points different from Embodiment 1 will be mainly described.

[0135] (Flow path and on-off valve) As shown in FIG. 6, the softening device 1b includes 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 respectively provided in each flow path, and switch between an "open" state and a "closed" state in each flow path. Further, the softening device 1b does not include a flow path corresponding to the flow path 29 of Embodiment 1. The softening device 1b is configured to supply acidic soft water to the separation unit 14 through a second supply flow path 23 instead of the flow path 29.

[0136] The second supply flow path 23 is a flow path that communicatively connects the electrolytic cell 12 and the flow path 8, and an on-off valve 42, an on-off valve 43, the separation unit 14, and an on-off valve 37 are provided in the flow path. Further, the second supply flow path 23 is communicatively connected to a drainage flow path 26a between the on-off valve 42 and the on-off valve 43.

[0137] The on-off valve 42 is provided between the connection point of 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 of 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 of the second supply flow path 23 and the flow path 8 and the separation unit 14. That is, the alkaline electrolyzed water sent out 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 flows into the flow path 8.

[0138] As shown in FIG. 7, the circulation channel 20c includes a first circulation channel 20d through which the water sent out from the water storage tank 15 by the water supply pump 19 flows through the water softening tank 3, and a second circulation channel 20e through which the water sent out from the water storage tank 15 by the water supply pump 19 flows through the neutralization tank 4.

[0139] As shown in FIG. 7 (white arrow), the first circulation channel 20d is a channel through which the water sent out from the water storage tank 15 by the water supply pump 19 circulates through the electrolysis tank 12 and the water softening tank 3 and then returns to the water storage tank 15. More specifically, the first circulation channel 20d is a channel through which the water sent out from the water storage tank 15 by the water supply pump 19 circulates in the order of the water supply channel 25, the electrolysis tank 12, the first supply channel 21, the on-off valve 35, the water softening tank 3, the first recovery channel 22, the on-off valve 36, and the water storage tank 15.

[0140] As shown in FIG. 7 (black arrow), the second circulation channel 20e is a channel through which the water sent out from the water storage tank 15 by the water supply pump 19 circulates through the electrolysis tank 12 and the neutralization tank 4 and then returns to the water storage tank 15. More specifically, the second circulation channel 20e is a channel through which the water sent out from the water storage tank 15 by the water supply pump 19 circulates in the order of the water supply channel 25, the electrolysis tank 12, the second supply channel 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 tank 4, the second recovery channel 24, the on-off valve 38, and the water storage tank 15. That is, in the water softening device 1b, when the regeneration process in which the second circulation channel 20e is formed is performed, the upstream side of the separation unit 14 is communicatively connected to the downstream side of the electrolysis tank 12.

[0141] The water softening device 1b also includes a drainage channel 26a. The drainage channel 26a is a channel for supplying the water discharged from the electrolysis tank 12 or the separation unit 14 to the drainage port 16 and discharging it outside the device. The drainage channel 26a is communicatively connected to the second supply channel 23 between the electrolysis tank 12 and the separation unit 14. An on-off valve 44 is provided in the drainage channel 26a. By opening the on-off valve 44, the drainage channel 26a is communicatively connected to the second supply channel 23. That is, the water softening device 1b includes a drainage channel 26a that can draw water from the second supply channel 23 to the drainage port 16 and discharge it outside the device.

[0142] As shown in FIG. 8, the separation unit cleaning channel 27b is composed of channels connecting the inlet 2, the water softening tank 3, the separation unit 14, and the drain port 16. That is, the water softening tank 3 is communicatively connected to the inlet 2 through the channel 7. Also, the water softening tank 3 is communicatively connected to the separation unit 14 through the channel 8 and the second supply channel 23. The separation unit 14 is communicatively connected to the drain port 16 through the second supply channel 23 and the drain channel 26a. The second supply channel 23 is provided with the separation unit 14, the on-off valve 37, the on-off valve 42, and the on-off valve 43. As shown in FIG. 8 (diagonal arrow), in the separation unit cleaning channel 27b, the water introduced from the inlet 2 flows through the channel 7 and the water softening tank 3 in this order. After being made into acidic soft water in the water softening tank 3, it flows through the channel 8, the second supply channel 23, and the separation unit 14 in this order, is subjected to the separation unit cleaning process, flows through the on-off valve 43 and the drain channel 26, and is a channel discharged outside the apparatus from the drain port 16. That is, in the water softening apparatus 1b, during the separation unit cleaning process, the separation unit 14 is configured such that acidic soft water flows into the separation unit 14 from the downstream side of the separation unit 14 and backwashing is performed.

[0143] (Regeneration process, separation unit cleaning process, drainage process, and water softening process) (Regeneration process) First, the operation during the regeneration process by the regeneration apparatus 6 of the water softening apparatus 1b will be described in order with reference to the columns of "Water injection" and "Regeneration" in FIG. 9.

[0144] First, as shown in FIG. 9, during water injection, the on-off valve 31 and the on-off valve 36 are opened. Thereby, the water softening apparatus 1 introduces raw water from the inlet 2 through the water softening tank 3 into the water storage tank 15 by the pressure of the 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 storage tank 15 according to the capacity of the water softening apparatus 1, the regeneration apparatus 6 can secure the amount of water during regeneration.

[0145] Next, during playback, when the on-off valves 31, 32, 34, and 44 are closed and the on-off valves 33, 35 to 39, and 42 to 43 are opened, the first circulation flow path 20d and the second circulation flow path 20e are respectively formed.

[0146] Then, when the electrode 13 of the electrolytic cell 12 and the water supply pump 19 are operated, the water stored in the water storage tank 15 is sent to the electrolytic cell 12, becomes acidic electrolyzed water and alkaline electrolyzed water by electrolysis, and circulates through the first circulation flow path 20d and the second circulation flow path 20e respectively.

[0147] At this time, the acidic electrolyzed water generated in the electrolytic cell 12 is sent into the softening tank 3 through the first supply flow path 21, and the weak acidic cation exchange resin 10 inside is regenerated by flowing through it. Then, the acidic electrolyzed water containing cations that has flowed through the weak acidic cation exchange resin 10 is recovered into the water storage tank 15 via the first recovery flow path 22.

[0148] On the other hand, the alkaline electrolyzed water generated in the electrolytic cell 12 is sent into the neutralization tank 4 through the second supply flow path 23 and the separation unit 14, and the weak basic anion exchange resin 11 inside is regenerated by flowing through it. Then, the alkaline electrolyzed water containing anions that has flowed through the weak basic anion exchange resin 11 is recovered into the water storage tank 15 via the second recovery flow path 24.

[0149] And in the water storage tank 15, the acidic electrolyzed water containing cations recovered from the 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 cell 12.

[0150] After that, the electrolyzed water mixed in the water storage tank 15 is passed through the water supply flow path 25 to the electrolytic cell 12 again. And the passed water is electrolyzed again in the electrolytic cell 12.

[0151] Then, in the softening water treatment device 1b, when the regeneration process is completed, the operation of the electrode 13 is stopped. Also, the on-off valves 33, 35 to 39, and 42 are closed, and the on-off valves 31, 32, and 44 are opened to shift to the separation unit cleaning process.

[0152] (Separation unit cleaning process) When the regeneration process of the softening water treatment device 1b is completed, it shifts to the separation unit cleaning process.

[0153] Next, the operation during the separation unit cleaning process by the softening water treatment device 1b will be described with reference to the "During separation unit cleaning" column in FIG. 9.

[0154] In the softening water treatment device 1b, as shown in FIG. 9, in the separation unit cleaning process, the on-off valves 31, 32, 37, 43, and 44 are opened. As a result, in the softening water treatment device 1, the separation unit cleaning flow path 27b is formed, and the separation unit 14 can be cleaned. At this time, the on-off valves 33 to 39 and the on-off valve 42 are closed.

[0155] As shown in FIG. 8, since the on-off valves 32 and 37 are opened and the on-off valves 33 and 36 are closed, the acidic soft water sent from the softening water tank 3 flows through the flow path 8 and the second supply flow path 23 and flows into the separation unit 14. By allowing the acidic soft water to flow into the separation unit 14, the precipitate caused by the hardness components captured in the separation unit 14 reacts with the acidic soft water. As a result, the precipitate caused by the hardness components dissolves and becomes a hardness component and is contained in the acidic soft water.

[0156] And, since the on-off valves 43 and 44 are opened and the on-off valve 42 is closed, the acidic soft water sent from the separation unit 14 flows through the second supply flow path 23 and the drainage flow path 26a and is discharged outside the device through the drainage port 16.

[0157] Then, in the softening water treatment device 1b, when the separation unit cleaning process is completed, the on-off valves 31 and 32 are closed, the on-off valves 33 and 35 to 44 are opened, and the water supply pump 19 is started to shift to the drainage treatment.

[0158] Note that the end of the separation unit cleaning process is set to be after a certain period of time (e.g., 1 hour) has elapsed since the start of the separation unit cleaning process. Here, the certain period of time is the time required to dissolve the precipitate captured by the separation unit 14, and is set based on the evaluation results of the previously conducted cleaning experiments.

[0159] (Wastewater treatment) In the water softening device 1b, when the separation unit cleaning process is completed, it shifts to the wastewater treatment. Here, the wastewater treatment is a process of discharging the raw water, acidic electrolyzed water, and alkaline electrolyzed water remaining in the circulation channel 20c.

[0160] Next, the operation during the wastewater treatment by the water softening device 1b will be described with reference to the "During wastewater discharge" column in FIG. 9.

[0161] In the water softening device 1b, as shown in FIG. 9, during the wastewater treatment (during wastewater discharge), the on-off valve 31, the on-off valve 32, and the on-off valve 34 are closed, and the on-off valve 33, the on-off valves 35 to 39, and the on-off valves 42 to 44 are opened. As a result, the inflow of city water from the inlet 2 is stopped, and the acidic electrolyzed water remaining in the path from the electrolytic cell 12 to the water storage tank 15 via the first supply channel 21, the water softening tank 3, and the first recovery channel 22 and the alkaline electrolyzed water remaining in the path from the separation unit 14 to the water storage tank 15 via the second supply channel 23, the neutralization tank 4, and the second recovery channel 24 can be made to flow into the water storage tank 15.

[0162] Next, during the wastewater treatment, the water supply pump 19 operates, the on-off valve 39, the on-off valve 42, and the on-off valve 44 are opened, and the electrode 13 stops operating. As a result, the electrolyzed water remaining in the path from the inside of the water storage tank 15 to the electrolytic cell 12 via the water supply channel 25 and the electrolyzed water remaining in the path from the inside of the electrolytic cell 12 to the drain port 16 via the second supply channel 23 and the drain channel 26 can be discharged outside the device.

[0163] Then, in the water softening device 1b, when the wastewater treatment is completed, the operation of the water supply 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 to 34 are opened to shift to the water softening treatment.

[0164] Note that the end of the wastewater treatment is defined as the elapse of a certain time (e.g., 1 minute) from the start of the wastewater treatment.

[0165] (Water softening treatment) When the wastewater treatment is completed, the water softening device 1b shifts to the water softening treatment.

[0166] The operation during the water softening treatment by the water softening device 1b will be described with reference to the "During water softening" column in FIG. 9.

[0167] In the water softening device 1b, as shown in FIG. 9, during the water softening treatment, with the on-off valves 31 to 33 open, the on-off valve 34 provided at the water intake 5 is opened. As a result, in the water softening device 1, municipal water (raw water containing hardness components) from the outside flows through the water softening tank 3 and the neutralization tank 4, so that the water softened (neutral soft water) can be taken out from the water intake 5. At this time, all of the on-off valves 35 to 39 and the on-off valves 42 to 44 are in the closed state. Also, the electrodes 13 of the electrolytic cell 12 and the operation of the water supply pump 19 are also stopped.

[0168] Then, in the water softening device 1b, when the time zone specified by the control unit 17 is reached or when the water softening treatment exceeds a certain time, the water softening treatment is stopped and the regeneration treatment is executed.

[0169] As described above, in the water softening device 1b, the regeneration treatment, the separation unit cleaning treatment, the wastewater treatment, and the water softening treatment are repeatedly executed.

[0170] As described above, according to the water softening device 1b according to the third embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be enjoyed.

[0171] (5) In the softening device 1b, the separation unit 14 is configured such that its upstream side is communicatively connected to the downstream side of the electrolytic cell 12. During the separation unit cleaning process, the separation unit 14 is configured such that acidic soft water flows into the separation unit 14 from the downstream side thereof. As a result, acidic soft water flows into the separation unit 14 from the downstream side. Since the electrolyzed water containing deposits caused by hardness components flows into the separation unit 14 from the upstream side of the separation unit 14, reverse cleaning of the separation unit 14 can be performed by flowing acidic soft water from the downstream side. Therefore, the processing efficiency of the separation unit cleaning process can be improved, and the separation unit cleaning process can be completed in a shorter period of time.

[0172] (Embodiment 4) Next, with reference to FIG. 10, the softening device 1c according to Embodiment 4 of the present invention will be described. FIG. 10 is a conceptual diagram showing the configuration of the softening device according to Embodiment 4.

[0173] The softening device 1c according to Embodiment 4 is different from Embodiment 1 in that an ion concentration detection unit 45 is provided at the subsequent stage of the separation unit 14 and before the selection valve 40. That is, in the softening device 1c according to Embodiment 4, based on the information regarding the ion concentration of the acidic soft water after flowing through the separation unit 14, when the ion concentration becomes less than the reference value, the control is performed to end the separation unit cleaning process. The configuration and control of the softening device 1c other than this are the same as those of the softening device 1 according to Embodiment 1. Hereinafter, the content already described in Embodiment 1 will be appropriately omitted from further explanation, and the points different from Embodiment 1 will be mainly described.

[0174] As shown in FIG. 10, the softening device 1c includes an ion concentration detection unit 45 at the subsequent stage of the separation unit 14 and before the selection valve 40 on the second supply flow path 23.

[0175] The ion concentration detection unit 45 detects ion concentration information regarding the ion concentration (for example, hardness component concentration) of the water flowing out of the separation unit 14 during the separation unit cleaning process. The ion concentration detection unit 45 is communicatively connected to the control unit 17 wirelessly or by wire, and the information regarding the detected ion concentration is used as an input signal to the control unit 17.

[0176] Here, as the ion concentration detector 45, a general-purpose one can be used. For example, a detector for measuring the electrical conductivity of a liquid or a detector for measuring the amount of TDS (Total Dissolved Solid) contained in water can be mentioned.

[0177] When the ion concentration specified based on the information on the ion concentration output from the ion concentration detector 45 is less than the reference value, the control unit 17 controls to end the separation unit cleaning process. On the other hand, when the ion concentration is equal to or higher than the reference value, the control unit 17 controls to continue the separation unit cleaning process. Thereby, the control unit 17 can determine the end of the separation unit cleaning process based on the ion concentration contained in the acidic soft water after flowing through the separation unit 14. Therefore, it is possible to flow the acidic soft water through the separation unit 14 until the ion concentration contained in the acidic soft water after flowing through the separation unit 14 becomes less than the reference value.

[0178] Here, the ion concentration specified based on the information on the ion concentration output from the ion concentration detector 45 is the ion concentration of the difference between the ion concentration contained in the acidic soft water after flowing through the separation unit 14 in a state where there is no precipitate in the separation unit 14 and the ion concentration contained in the acidic soft water after flowing through the separation unit 14 during the separation unit cleaning process. And the reference value is a value defined so that the ion concentration of the difference is within a predetermined range.

[0179] As described above, according to the water softening device 1c according to the fourth embodiment, in addition to the effects (1) and (2) obtained by the first embodiment, the following effects can be enjoyed.

[0180] (6) In the water softening device 1c, an ion concentration detection unit 45 for detecting ion concentration information regarding the ion concentration of the water flowing out of the separation unit 14 is further provided, and the end of the separation unit cleaning process is configured to be performed based on the ion concentration information. Thereby, the cleaning state of the separation unit 14 during the separation unit cleaning process can be grasped, and the end of the separation unit cleaning process can be determined based on the ion concentration information. Therefore, the cleaning of the separation unit 14 can be completed more reliably.

[0181] As described above, the embodiments of the present invention have been described based on the embodiments. These embodiments are examples, and it is understood by those skilled in the art that various modifications are possible for each of these constituent elements or combinations of each processing process, and such modifications are also within the scope of the present invention.

[0182] Also, in the water softening device 1 according to the first embodiment, although it is configured to repeatedly execute the regeneration process, the separation unit cleaning process, the drainage process, and the water softening process in this order, it is not limited thereto. For example, it may be configured to repeatedly execute the regeneration process, the drainage process, and the water softening process in this order, and perform the separation unit cleaning process by specifying the timing when the cleaning of the separation unit 14 becomes necessary by detecting the ion concentration. Further, it may be configured to repeatedly execute the regeneration process, the drainage process, and the water softening process in this order, and perform the separation unit cleaning process once in a certain period (for example, one day). Further, the control unit 17 may specify the time when the water softening process is not being performed, and control to perform the separation unit cleaning process during the time when the water softening process is not being performed. By doing so, the frequency of performing the separation unit cleaning process can be reduced. Therefore, it is possible to shorten the time from the end of the water softening process to the start of the next water softening process.

[0183] In addition, in the water softening device 1a according to the second embodiment, after the wastewater treatment is completed, the water softening treatment and the separation unit cleaning treatment are performed in parallel, and after a certain period of time has elapsed, the separation unit cleaning treatment is terminated and the water softening treatment is continued. However, the present invention is not limited to this. For example, after the wastewater treatment is completed, the water softening treatment may be performed, and after a certain period of time has elapsed, the water softening treatment and the separation unit cleaning treatment may be performed in parallel. Further, after the wastewater treatment is completed, the water softening treatment may be performed, and after a certain period of time, the water softening treatment and the separation unit cleaning treatment may be performed in parallel, and then the process may return to the water softening treatment again. By doing so, it becomes possible to clean the separation unit 14 at a predetermined timing. Therefore, it is possible to clean the separation unit 14 while obtaining a required amount of softened water from the water intake port 5.

[0184] In addition, in the water softening device 1 according to the first embodiment, the regeneration process is executed when the time zone specified by the control unit 17 is reached or when the water softening process exceeds a certain period of time. However, the present invention is not limited to this. For example, an ion concentration detection unit different from the ion concentration detection unit 45 may be provided downstream of the neutralization tank 4 and upstream of the on-off valve 34, and the ion concentration detection unit may constantly detect the ion concentration (for example, the hardness component concentration) of the softened water flowing through the flow path 9, and when the ion concentration exceeds a preset reference value, the regeneration process may be executed. Thereby, based on the ion concentration of the water after flowing through the neutralization tank 4, it is possible to determine whether to execute the regeneration process. Therefore, when the regeneration process is required, the weak acidic cation exchange resin 10 and the weak basic anion exchange resin 11 can be regenerated.

Industrial Applicability

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

Explanation of Reference Numerals

[0186] 1 Water softening device 1a Water softening device 1b Water softening device 1c Softening device 2 Inlet 3 Softening tank 4 Neutralization tank 5 Water intake 6 Regeneration device 7 Flow path 8 Flow path 9 Flow path 10 Weak acid cation exchange resin 11 Weak base anion exchange resin 12 Electrolytic cell 13 Electrode 13a Electrode 13b Electrode 14 Separation section 15 Water storage tank 16 Drain outlet 17 Control section 19 Water supply pump 20 Circulation flow path 20a First circulation flow path 20b Second circulation flow path 20c Circulation flow path 20d First circulation flow path 20e Second circulation flow path 21 First supply flow path 22 First recovery flow path 23 Second supply flow path 24 Second recovery flow path 25 Water supply flow path 26 Drainage flow path 26a Drainage flow path 27 Separation section cleaning flow path 27a Separation section cleaning flow path 27b Separation section cleaning flow path 28 Raw water softening flow path 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 Selective valve 41 On-off valve 41a On-off valve 42 On-off valve 43 On-off valve 44 On-off valve 45 Ion concentration detector

Claims

1. A softening tank that softens raw water containing a hardness component by a weakly acidic cation exchange resin; A neutralization tank that neutralizes the pH of the softened water that has passed through the softening tank by a weakly basic anion exchange resin; An electrolytic cell that generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the 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 cell and the neutralization tank, for separating precipitates caused by the hardness component contained in the water introduced into the electrolytic cell; Comprising; A softening device characterized in that after performing a regeneration process on the softening tank and the neutralization tank, a separation unit cleaning process is performed in which the acidic softened water that has flowed through the softening tank is caused to flow through the separation unit and discharged outside the device.

2. The separation unit cleaning process is performed by causing a part of the acidic softened water that has flowed through the softening tank to flow through the separation unit during a period in which the raw water is being softened by the softening tank and the neutralization tank. The softening device according to claim 1.

3. The separation unit cleaning process is performed by causing the acidic softened water to flow into the separation unit from the downstream side of the separation unit. The softening device according to claim 1 or 2.

4. When the separation unit cleaning process is completed, the flow of the acidic softened water to the separation unit is stopped. The softening device according to any one of claims 1 to 3.

5. The completion of the separation unit cleaning process is after a certain period from the start of the separation unit cleaning process. The softening device according to claim 4.

6. Further comprising an ion concentration detection unit that detects ion concentration information regarding the ion concentration of the water flowing out of the separation unit; The completion of the separation unit cleaning process is performed based on the ion concentration information. The softening device according to claim 4.

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