JP7769852B2 - water softener - Google Patents

Description

The present invention relates to a water softening device for obtaining water for daily use.

In conventional water softeners using weakly acidic cation exchange resins, a known method of regenerating the cation exchange resin without using salt is to regenerate the cation exchange resin using acidic electrolyzed water (see, for example, Patent Document 1). Weakly acidic cation exchange resins have protons (hydrogen ions) at the terminals of their functional groups, and soften the raw water by exchanging hardness components (e.g., calcium ions, magnesium ions) in the raw water for protons. Furthermore, water softened by weakly acidic cation exchange resins becomes acidic due to the release of protons in place of hardness ions. To neutralize this acidity, weakly acidic cation exchange resins are sometimes used in combination with weakly basic anion exchange resins. Another known method of regenerating this anion exchange resin is to use alkaline electrolyzed water. Weakly basic anion exchange resins neutralize the softened raw water by adsorbing the protons and anions contained in the water softened by the weakly acidic cation exchange resin.

JP 2011-30973 A

In such conventional water softeners, if the regeneration of the weakly acidic cation exchange resin is completed before the regeneration of the weakly basic anion exchange resin, for example, the hydrogen ions used to regenerate the weakly acidic cation exchange resin react with hydroxide ions, resulting in the consumption of hydroxide ions through neutralization. As described above, if the regeneration of one ion exchange resin is completed first, the regeneration performance of the other ion exchange resin decreases, which is an issue.

The present invention aims to solve the above-mentioned problems of the prior art by providing a water softening device that can suppress the decline in the regeneration efficiency of a weakly acidic cation exchange resin and a weakly basic anion exchange resin when the regeneration process of one ion exchange resin is completed, even if the other ion exchange resin is regenerated.

To achieve this object, the water softening device according to the present invention comprises a water softening tank, a neutralization tank, an electrolytic tank, and a capture unit . The water softening tank softens raw water containing hardness components using a weakly acidic cation exchange resin. The neutralization tank neutralizes the softened water that has passed through the water softening tank using a weakly basic ion exchange resin. The electrolytic tank produces acidic electrolyzed water for regenerating the weakly acidic cation exchange resin and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin. The electrolytic tank has a first outlet for sending the acidic electrolyzed water to the water softening tank, a first water intake for taking in the water that has passed through the water softening tank, a second outlet for sending the alkaline electrolyzed water to the neutralization tank, and a second water intake for taking in the water that has passed through the neutralization tank. The water softener has an acidic electrolyzed water circulation flow path that circulates acidic electrolyzed water through an electrolytic cell, a first outlet, a water softening cell, and a first inlet in this order, and an alkaline electrolyzed water circulation flow path that circulates alkaline electrolyzed water through an electrolytic cell, a second outlet, a neutralization cell, and a second inlet in this order. The capture unit is provided in the alkaline electrolyzed water circulation flow path after the second outlet and before the neutralization cell, and separates solids in the alkaline electrolyzed water, thereby achieving the intended purpose.

The present invention provides a water softening device that can suppress a decrease in the regeneration efficiency of a weakly acidic cation exchange resin and a weakly basic anion exchange resin when the regeneration process of one ion exchange resin is completed, even if the other ion exchange resin is regenerated.

FIG. 1 is a conceptual diagram showing the configuration of a water softening device according to a first embodiment of the present invention. FIG. 2 is a diagram showing the acidic electrolyzed water circulation flow path and alkaline electrolyzed water circulation flow path of the water softener. FIG. 3 is a diagram showing the state of the water softening device during operation.

The water softening device of the present invention comprises a water softening tank, a neutralization tank, and an electrolytic tank. The water softening tank softens raw water containing hardness components using a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water that has passed through the water softening tank using a weakly basic ion exchange resin. The electrolytic tank produces acidic electrolyzed water for regenerating the weakly acidic cation exchange resin and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin. The electrolytic tank has a first outlet for sending the acidic electrolyzed water to the water softening tank, a first water intake for taking in water that has passed through the water softening tank, a second outlet for sending the alkaline electrolyzed water to the neutralization tank, and a second water intake for taking in water that has passed through the neutralization tank. The water softener is configured to have an acidic electrolyzed water circulation flow path that circulates acidic electrolyzed water through the electrolytic cell, first outlet, water softening cell, and first intake port in that order, and an alkaline electrolyzed water circulation flow path that circulates alkaline electrolyzed water through the electrolytic cell, second outlet, neutralization cell, and second intake port in that order.

As a result, during the regeneration process, acidic electrolyzed water flows through the acidic electrolyzed water circulation flow path, and alkaline electrolyzed water flows through the alkaline electrolyzed water circulation flow path, preventing mixing of the acidic electrolyzed water and alkaline electrolyzed water. Therefore, even after the regeneration of one ion exchange resin is complete, acidic electrolyzed water with an acidic pH flows through the acidic electrolyzed water circulation flow path, and alkaline electrolyzed water with an alkaline pH flows through the alkaline electrolyzed water circulation flow path, preventing a decrease in the regeneration efficiency of the other ion exchange resin.

In addition, in the water softening device according to the present invention, the electrolytic cell may be configured to include an anode chamber containing an anode, a cathode chamber containing a cathode, and a diaphragm disposed between the anode chamber and the cathode chamber. The electrolytic cell is characterized in that acidic electrolyzed water is produced in the anode chamber and alkaline electrolyzed water is produced in the cathode chamber. With this configuration, the anode chamber and cathode chamber of the electrolytic cell are separated by the diaphragm, making it possible to suppress the neutralization reaction of protons and hydroxide ions caused by mixing of acidic electrolyzed water and alkaline electrolyzed water. This makes it possible to suppress a decrease in the regeneration efficiency of the weakly acidic cation exchange resin and the weakly basic anion exchange resin.

The water softening device according to the present invention may also be configured to include an acidic electrolyzed water circulation pump installed in the acidic electrolyzed water circulation flow path and an alkaline electrolyzed water circulation pump installed in the alkaline electrolyzed water circulation flow path. This makes it possible to control the flow rates of acidic electrolyzed water circulating through the acidic electrolyzed water circulation flow path and alkaline electrolyzed water circulating through the alkaline electrolyzed water circulation flow path. Therefore, by controlling the flow rates to a constant level for regenerating each ion exchange resin using the acidic electrolyzed water circulation pump and the alkaline electrolyzed water circulation pump, it is possible to maintain a constant regeneration performance for the weakly acidic cation exchange resin and the weakly basic anion exchange resin.

The water softener according to the present invention may also be configured to include an acidic electrolyzed water storage tank in the acidic electrolyzed water circulation flow path, downstream of the water softener tank and upstream of the first water intake. With this configuration, storing acidic electrolyzed water in the acidic electrolyzed water storage tank makes it possible to control the total amount of acidic electrolyzed water circulating within the acidic electrolyzed water circulation flow path.

The water softener according to the present invention may also be configured to include an alkaline electrolyzed water storage tank in the alkaline electrolyzed water circulation flow path, downstream of the neutralization tank and upstream of the second water intake. With this configuration, storing alkaline electrolyzed water in the alkaline electrolyzed water storage tank makes it possible to control the total amount of alkaline electrolyzed water circulating in the alkaline electrolyzed water circulation flow path.

The water softener according to the present invention may also be configured to include a capture unit that separates solids from the alkaline electrolyzed water, located downstream of the second outlet and upstream of the neutralization tank in the alkaline electrolyzed water circulation flow path. This configuration makes it possible to separate solids that are generated when alkaline electrolyzed water is produced. This prevents solids from flowing into and accumulating in the neutralization tank, thereby preventing performance degradation during the water softening process.

Furthermore, the water softening device according to the present invention may be configured so that, when regenerating the weakly acidic cation exchange resin, the acidic electrolyzed water discharged from the first discharge port flows into the water softening tank from the downstream side. This allows the acidic electrolyzed water discharged from the anode chamber of the electrolytic tank to flow into the water softening tank from the downstream side, where less hardness components are adsorbed, during regeneration, thereby regenerating the water softening tank. Since less protons are consumed in the acidic electrolyzed water downstream than in the upstream side during regeneration of the weakly acidic cation exchange resin, a decrease in the proton concentration of the acidic electrolyzed water can be suppressed. Therefore, the hardness components contained in the acidic electrolyzed water from the downstream side can be suppressed from being re-adsorbed in the upstream side. This prevents a decrease in the regeneration efficiency of the water softening tank and shortens the regeneration time.

Furthermore, the water softener according to the present invention may be configured such that, when regenerating the weakly basic anion exchange resin, the alkaline electrolyzed water discharged from the second outlet flows into the neutralization tank from the downstream side. This allows the alkaline electrolyzed water discharged from the cathode chamber of the electrolytic tank to flow into the neutralization tank from the downstream side, where a smaller amount of anion components is adsorbed, during regeneration, thereby regenerating the neutralization tank. Since less hydroxide ions are consumed in the alkaline electrolyzed water downstream than in the upstream side during regeneration of the weakly basic anion exchange resin, a decrease in the hydroxide ion concentration in the alkaline electrolyzed water can be suppressed. Therefore, it is possible to suppress re-adsorption of anions contained in the alkaline electrolyzed water from the downstream side in the upstream side. This prevents a decrease in the regeneration efficiency of the neutralization tank and shortens the regeneration time.

In addition, the water softening tank of the water softening device according to the present invention may include a first water softening tank and a second water softening tank, and the neutralization tank may include a first neutralization tank and a second neutralization tank. When raw water is softened, it may flow through the first water softening tank, the first neutralization tank, the second water softening tank, and the second neutralization tank in that order. This allows raw water containing hardness components to exit the first water softening tank before the pH of the raw water decreases due to softening treatment in the first water softening tank. The raw water is then neutralized in the first neutralization tank, softened in the second water softening tank, and neutralized in the second neutralization tank. This prevents the pH of the water flowing through the water softening tank from decreasing, i.e., becoming acidic, compared to when the water softening tank and neutralization tank are configured separately. This facilitates exchange of hardness components with protons held by the weakly acidic cation exchange resin in the water softening tank (particularly the second water softening tank). This improves water softening performance.

Furthermore, in the water softening device according to the present invention, during the regeneration process for regenerating the weakly acidic cation exchange resin, the acidic electrolyzed water discharged from the anode chamber of the electrolytic cell may be configured to flow through the second water softening cell and then through the first water softening cell. In this way, during the regeneration process, the acidic electrolyzed water discharged from the anode chamber of the electrolytic cell flows into the second water softening cell, which adsorbs fewer hardness components than the first water softening cell, and the acidic electrolyzed water containing hardness components is discharged from the second water softening cell to the first water softening cell. During the regeneration of the weakly acidic cation exchange resin in the second water softening cell, less protons are consumed in the acidic electrolyzed water than in the first water softening cell, thereby suppressing a decrease in proton concentration compared to regeneration of the first water softening cell. Therefore, acidic electrolyzed water containing a large amount of protons flows into the first water softening cell, suppressing re-adsorption of hardness components in the first water softening cell. This prevents a decrease in regeneration efficiency and shortens the regeneration time.

Furthermore, the water softening device according to the present invention may be configured such that, during the regeneration process for regenerating the weakly basic anion exchange resin, alkaline electrolyzed water discharged from the cathode chamber of the electrolytic cell flows through the second neutralization cell and then through the first neutralization cell. This allows the alkaline electrolyzed water discharged from the cathode chamber of the electrolytic cell to flow into the second neutralization cell, which adsorbs fewer anions than the first neutralization cell, and the alkaline electrolyzed water containing anions is discharged from the second neutralization cell to the first neutralization cell. During the regeneration of the weakly basic anion exchange resin in the second neutralization cell, less hydroxide ions are consumed in the alkaline electrolyzed water than in the first neutralization cell, so the reduction in hydroxide ion concentration can be suppressed compared to the regeneration of the first neutralization cell. Therefore, alkaline electrolyzed water containing a large amount of hydroxide ions flows into the first neutralization cell, and the re-adsorption of anions in the first neutralization cell can be suppressed. This prevents a decrease in regeneration efficiency and shortens the regeneration time.

Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention. Furthermore, the figures described in the embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components in each figure do not necessarily reflect the actual dimensional ratios.

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

(Overall structure)
The water softener 1 is an apparatus that converts city water (raw water containing hardness components) supplied from the outside into neutral softened water suitable for daily use. Specifically, as shown in Fig. 1 , the water softener 1 includes an inlet 2 for raw water from the outside, a water softening tank 3, a neutralization tank 4, an intake 5 for treated softened water, and a regeneration device 6. The water softening tank 3 includes a first water softening tank 3a and a second water softening tank 3b. The neutralization tank 4 includes a first neutralization tank 4a and a second neutralization tank 4b. The regeneration device 6 includes an electrolytic tank 9, an acidic electrolyzed water storage tank 19, an acidic electrolyzed water circulation pump 23, an alkaline electrolyzed water storage tank 21, an alkaline electrolyzed water circulation pump 24, and a capture unit 25. The water softening device 1 also includes a plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, on-off valves 71 and 72) and a control unit 26.

Inlet 2 is connected to city water (raw water containing hardness components). Inlet 2 is an opening through which city water (raw water containing hardness components) is introduced into the device.

The water intake 5 is an opening for discharging the neutral softened water processed in the water softening tank 3 and neutralization tank 4 to the outside of the device. In other words, the water softening device 1 can extract softened water from the water intake 5 using city water pressure.

The inlet 2 is connected to the water intake 5 by flow paths 30, 31, 32, 33, and 34. Flow path 30 connects the inlet 2 to the first water softening tank 3a. Flow path 31 connects the first water softening tank 3a to the first neutralization tank 4a. Flow path 32 connects the first neutralization tank 4a to the second water softening tank 3b. Flow path 33 connects the second water softening tank 3b to the second neutralization tank 4b. Flow path 34 connects the second neutralization tank 4b to the water intake 5.

In other words, flow path 30 is a flow path that guides raw water containing hardness components from inlet 2 to first water softening tank 3a. Flow path 31 is a flow path that guides water softened in first water softening tank 3a to first neutralization tank 4a. Flow path 32 is a flow path that guides water neutralized in first neutralization tank 4a to second water softening tank 3b. Flow path 33 is a flow path that guides water softened in second water softening tank 3b to second neutralization tank 4b. Flow path 34 is a flow path that guides water neutralized in second neutralization tank 4b (softened water) to water intake 5.

In other words, in the water softening process in the water softening device 1, city water supplied from outside flows through the inlet 2, flow path 30, first water softening tank 3a, flow path 31, first neutralization tank 4a, flow path 32, second water softening tank 3b, flow path 33, second neutralization tank 4b, flow path 34, and water intake 5 in that order, before being discharged as neutral softened water.

(Water softening tank and neutralization tank)
The water softening tank 3 is configured, for example, by filling a cylindrical container with a weakly acidic cation exchange resin 7. The neutralization tank 4 is configured, for example, by filling a cylindrical container with a weakly basic anion exchange resin 8.

The water softening tank 3 is composed of a first water softening tank 3a and a second water softening tank 3b. The first water softening tank 3a is filled with a first weakly acidic cation exchange resin 7a. The second water softening tank 3b is filled with a second weakly acidic cation exchange resin 7b. The first water softening tank 3a and the second water softening tank 3b have weakly acidic cation exchange resins 7 with the same flow path length, flow path cross-sectional area, and volume. Note that below, the first weakly acidic cation exchange resin 7a and the second weakly acidic cation exchange resin 7b will be referred to as the weakly acidic cation exchange resin 7 when there is no need to distinguish between them.

The neutralization tank 4 is composed of a first neutralization tank 4a and a second neutralization tank 4b. The first neutralization tank 4a is composed, for example, of a cylindrical container filled with a first weakly basic anion exchange resin 8a. The second neutralization tank 4b is composed of a second weakly basic anion exchange resin 8b filled with the first weakly basic anion exchange resin 8a. The first neutralization tank 4a and the second neutralization tank 4b have the same flow path length, flow path cross-sectional area, and volume of weakly basic anion exchange resin 8. Hereinafter, the first weakly basic anion exchange resin 8a and the second weakly basic anion exchange resin 8b will be referred to as the weakly basic anion exchange resin 8 when there is no need to particularly distinguish between them.

The weakly acidic cation exchange resin 7 is not particularly limited and can be any general-purpose resin, such as one that uses a carboxyl group (-COOH) as the exchange group. It may also be one in which the proton (H+), the counter ion of the carboxyl group, is replaced by a cation such as a metal ion or ammonium ion (NH4+).

Furthermore, there are no particular restrictions on the weakly basic anion exchange resin 8, and any general-purpose resin can be used, such as a free base type.

The water softening tank 3 softens raw water containing hardness components through the action of weakly acidic cation exchange resins 7. More specifically, the water softening tank 3 is equipped with weakly acidic cation exchange resins 7 that have protons at the ends of their functional groups. The water softening tank 3 exchanges cations (calcium ions, magnesium ions), which are hardness components contained in the flowing water (raw water), with hydrogen ions, thereby reducing the hardness of the raw water and softening the raw water. Furthermore, because the ends of the functional groups of the weakly acidic cation exchange resins 7 are protons, the weakly acidic cation exchange resins 7 can be regenerated using acidic electrolyzed water in the regeneration process described below. During this process, the weakly acidic cation exchange resins 7 release the cations, which are hardness components, that were captured during the water softening process.

More specifically, raw water containing hardness components is passed through the first water softening tank 3a via flow path 30. The raw water containing hardness components is softened by passing through the first weakly acidic cation exchange resin 7a filled inside. The softened water is then passed through flow path 31 to the first neutralization tank 4a. However, water softened by the first weakly acidic cation exchange resin 7a contains many protons that have been exchanged with hardness components and released, resulting in acidic water with a low pH. Water containing a large amount of permanent hardness components (e.g., sulfates such as calcium sulfate or chlorides such as magnesium chloride) is more likely to experience a drop in pH during softening than water containing a large amount of temporary hardness components (e.g., carbonates such as calcium carbonate). Because softening is difficult when the pH is low, the water that has passed through the first water softening tank 3a is passed through the first neutralization tank 4a for neutralization.

Meanwhile, in the second water softening tank 3b, neutralized water is passed through the flow path 32 and passes through the second weakly acidic cation exchange resin 7b filled inside. As a result, hardness components that could not be removed in the first water softening tank 3a are exchanged for protons possessed by the second weakly acidic cation exchange resin 7b. As a result, the water that flows into the second water softening tank 3b is softened. However, the water softened by the second weakly acidic cation exchange resin 7b is acidic because it contains protons that have been exchanged for hardness components and have flowed out.

The neutralization tank 4 neutralizes the pH of the proton-containing softened water (acidified softened water) coming out of the water softening tank 3 through the action of the weakly basic anion exchange resin 8, converting it into neutral soft water. More specifically, the neutralization tank 4 is equipped with the weakly basic anion exchange resin 8, which adsorbs the protons contained in the softened water from the water softening tank 3 along with the anions, thereby raising the pH of the softened water and turning it into neutral soft water. Furthermore, the weakly basic anion exchange resin 8 can be regenerated using alkaline electrolyzed water in the regeneration process described below.

More specifically, in the first neutralization tank 4a, softened water containing protons is passed through the flow path 31 and flows through the first weakly basic anion exchange resin 8a filled inside, neutralizing the acidic water that flowed out of the first water softening tank 3a, and the neutral water is then sent to the second water softening tank 3b via the flow path 32. In other words, the first neutralization tank 4a neutralizes the acidic water that flowed out of the first water softening tank 3a and contains protons released from the first weakly acidic cation exchange resin 7a, and sends the water that flowed through the first neutralization tank 4a to the second water softening tank 3b as water that is easy to soften due to its neutral pH.

Meanwhile, in the second neutralization tank 4b, softened water containing protons is passed through flow path 33 and flows through the second weakly basic anion exchange resin 8b filled inside, neutralizing the acidified softened water discharged from the second water softening tank 3b and passing it to the outside as neutral softened water through flow path 34. In other words, the second neutralization tank 4b neutralizes the acidic water discharged from the second water softening tank 3b and the acidic water containing hydrogen ions released from the second weakly acidic cation exchange resin 7b, thereby discharging softened water usable for domestic use from the water intake 5.

(Playback device)
The regeneration device 6 is a device for regenerating the weakly acidic cation exchange resin 7 in the water softening tank 3 and the weakly basic anion exchange resin 8 in the neutralization tank 4. Specifically, the regeneration device 6 includes the electrolytic tank 9, the acidic electrolyzed water storage tank 19, the acidic electrolyzed water circulation pump 23, the alkaline electrolyzed water storage tank 21, the alkaline electrolyzed water circulation pump 24, and the capture unit 25, as described above. In the regeneration device 6, a first supply flow path 41, a first recovery flow path 43, a second supply flow path 45, and a second recovery flow path 47 are connected to the flow path 33, the flow path 30, the flow path 34, and the flow path 31, respectively, from the inlet 2 to the water intake 5. Furthermore, the flow path 31 and the flow path 32 are connected by a first bypass flow path 42. Furthermore, the flow path 32 and the flow path 33 are connected by a second bypass flow path 46. The flow paths constitute an acidic electrolyzed water circulation flow path 40 and an alkaline electrolyzed water circulation flow path 44, which will be described later. Here, the first supply flow path 41 is a flow path for supplying acidic electrolyzed water from the electrolytic cell 9 to the second water softening cell 3b. The first bypass flow path 42 is a flow path for supplying acidic electrolyzed water, which has passed through the second water softening cell 3b, to the first water softening cell 3a, bypassing the first neutralization cell 4a. The first recovery flow path 43 is a flow path for recovering acidic electrolyzed water containing hardness components, which has flowed out of the water softening cell 3 during the regeneration treatment of the water softening cell 3, to the acidic electrolyzed water storage cell 19. The second supply flow path 45 is a flow path for supplying alkaline electrolyzed water from the electrolytic cell 9 to the second neutralization cell 4b. The second bypass flow path 46 is a flow path for supplying alkaline electrolyzed water, which has passed through the second neutralization cell 4b, to the first neutralization cell 4a, bypassing the second water softening cell 3b. The second recovery flow path 47 is a flow path for recovering alkaline electrolyzed water, which has passed through the first neutralization cell 4a, to the alkaline electrolyzed water storage cell 21. The water supply flow path 48 is a flow path for supplying the acidic electrolyzed water stored in the acidic electrolyzed water storage tank 19 to the anode chamber 14 of the electrolytic cell 9 using the acidic electrolyzed water circulation pump 23. The water supply flow path 49 is a flow path for supplying the alkaline electrolyzed water stored in the alkaline electrolyzed water storage tank 21 to the cathode chamber 18 of the electrolytic cell 9 using the alkaline electrolyzed water circulation pump 24.

(electrolytic cell)
The electrolytic cell 9 includes a diaphragm 10, an anode chamber 14, and a cathode chamber 18. The electrolytic cell 9 is separated into the anode chamber 14 and the cathode chamber 18 by the diaphragm 10 provided inside.

The diaphragm 10 is a fluorine-based porous membrane that prevents the mixing of acidic electrolyzed water generated in the anode chamber 14 and alkaline electrolyzed water generated in the cathode chamber 18 by electrolysis. This prevents hydrogen ions in the acidic electrolyzed water and hydroxide ions in the alkaline electrolyzed water from being consumed by the neutralization reaction, thereby preventing a decrease in the regeneration efficiency of the weakly acidic cation exchange resin 7 and the weakly basic anion exchange resin 8. Furthermore, a decrease in the regeneration efficiency of one ion exchange resin when the regeneration of the other ion exchange resin is completed first can also be prevented. Specifically, without the diaphragm 10, an environment in which acidic electrolyzed water and alkaline electrolyzed water are easily mixed would be created. For example, if the regeneration of the weakly acidic cation exchange resin 7 is completed before the regeneration of the weakly basic anion exchange resin 8, the hydrogen ions in the acidic electrolyzed water used to regenerate the weakly acidic cation exchange resin 7 react with the hydroxide ions in the alkaline electrolyzed water, resulting in the consumption of hydroxide ions through neutralization. In other words, without the diaphragm 10, if one ion exchange resin completes regeneration first, the regeneration efficiency of the other ion exchange resin is likely to decrease. However, by separating the interior of the electrolytic cell 9 into the anode chamber 14 and the cathode chamber 18 using the diaphragm 10, even when one ion exchange resin completes regeneration, it is possible to prevent mixing with the electrolytic water used to regenerate the other ion exchange resin. Therefore, the diaphragm 10 also prevents a decrease in the regeneration efficiency of one ion exchange resin when the other ion exchange resin completes regeneration first. Note that, in addition to fluorine-based porous membranes, commonly used porous membranes such as hydrocarbon-based porous membranes may also be used as the porous membrane for the diaphragm 10. However, fluorine-based porous membranes have superior durability, so a fluorine-based porous membrane is used in the water softening device 1.

The anode chamber 14 includes an anode 11, a first water inlet 12, and a first outlet 13. The anode 11 generates hydrogen ions by electrolyzing water. A platinum electrode, for example, can be used as the anode 11. The first water inlet 12 is an opening through which acidic electrolyzed water stored in an acidic electrolyzed water storage tank 19 is introduced into the anode chamber 14 through a water supply flow path 48. The first outlet 13 is an opening through which acidic electrolyzed water containing hydrogen ions generated by the anode 11 is supplied to the water softening tank 3 through a first supply flow path 41. The acidic electrolyzed water supplied from the electrolytic tank 9 to the water softening tank 3 is used to regenerate the weakly acidic cation exchange resin 7. The cathode chamber 18 includes a cathode 15, a second water inlet 16, and a second outlet 17. The cathode 15 generates hydroxide ions by electrolyzing water. A platinum electrode, for example, can be used as the cathode 15. The second water intake 16 is an opening for introducing alkaline electrolyzed water stored in the alkaline electrolyzed water storage tank 21 into the cathode chamber 18 through the water supply passage 49. The second discharge port 17 is an opening for supplying alkaline electrolyzed water containing hydroxide ions produced at the cathode 15 to the neutralization tank 4 through the second supply passage 45. The alkaline electrolyzed water supplied from the electrolysis tank 9 to the neutralization tank 4 is used for regenerating the weakly basic anion exchange resin 8.
The electrolytic cell 9 is configured so that the state of current flow to the anode 11 and the cathode 15 can be controlled by a control unit 26 described later.

(Acidic electrolyzed water storage tank and alkaline electrolyzed water storage tank)
The acidic electrolyzed water storage tank 19 is a tank or container equipped with an air vent valve 20. The acidic electrolyzed water storage tank 19 secures and stores water to be circulated through the acidic electrolyzed water circulation flow path 40 (see FIG. 2) when regenerating the weakly acidic cation exchange resin 7. The air vent valve 20 removes gas contained in the acidic electrolyzed water to prevent gas from accumulating in the acidic electrolyzed water circulation flow path 40. The alkaline electrolyzed water storage tank 21 is a tank or container equipped with an air vent valve 22.

Storing acidic electrolyzed water in the acidic electrolyzed water storage tank 19 makes it possible to control the total amount of acidic electrolyzed water circulating through the acidic electrolyzed water circulation flow path 40. For example, by increasing the volume of the acidic electrolyzed water storage tank 19, the ion concentration in the acidic electrolyzed water circulation flow path 40 can be reduced when the amount of ions in the acidic electrolyzed water circulation flow path 40 is constant. A decrease in the concentration of cations such as hardness components shifts the equilibrium of the reaction in the weakly acidic cation exchange resin 7 toward the regeneration reaction (the reaction in which hardness components are desorbed from the weakly acidic cation exchange resin 7 and hydrogen ions are adsorbed), thereby improving regeneration efficiency. Furthermore, by decreasing the volume of the acidic electrolyzed water storage tank 19, the ion concentration in the acidic electrolyzed water circulation flow path 40 can be increased when the amount of ions (cations such as hardness components) in the acidic electrolyzed water circulation flow path 40 is constant. The increase in the ion concentration of acidic electrolyzed water reduces the solution resistance during electrolysis in the electrolytic cell 9. This allows the voltage applied to the electrolytic cell 9 to be reduced, thereby reducing power consumption. In other words, by using an acidic electrolyzed water storage tank 19 with a volume appropriate for the purpose, the performance of the water softener 1 can be improved.

The alkaline electrolyzed water storage tank 21 secures and stores water to circulate through the alkaline electrolyzed water circulation flow path 44 (see Figure 2) when regenerating the weakly basic anion exchange resin 8. The air vent valve 22 removes gas contained in the alkaline electrolyzed water to prevent gas from accumulating in the alkaline electrolyzed water circulation flow path 44.

Storing alkaline electrolyzed water in the alkaline electrolyzed water storage tank 21 makes it possible to control the total amount of alkaline electrolyzed water circulating through the alkaline electrolyzed water circulation flow path 44. For example, by increasing the volume of the alkaline electrolyzed water storage tank 21, the ion concentration in the alkaline electrolyzed water circulation flow path 44 can be reduced when the amount of ions in the alkaline electrolyzed water circulation flow path 44 is constant. The reduction in anion concentration shifts the equilibrium of the reaction in the weakly basic anion exchange resin 8 toward the regeneration reaction, thereby improving regeneration efficiency. Furthermore, by reducing the volume of the alkaline electrolyzed water storage tank 21, the ion concentration in the alkaline electrolyzed water circulation flow path 44 can be increased when the amount of ions in the alkaline electrolyzed water circulation flow path 44 is constant. The increase in the ion concentration of alkaline electrolyzed water reduces the solution resistance during electrolysis in the electrolytic cell 9. This allows the voltage applied by the electrolytic cell 9 to be reduced, thereby reducing power consumption. In other words, the performance of the water softener 1 can be improved by using an alkaline electrolyzed water storage tank 21 with a volume appropriate for the purpose.

(Acidic electrolyzed water circulation pump and alkaline electrolyzed water circulation pump)
The acidic electrolyzed water circulation pump 23 is a device that circulates water through the acidic electrolyzed water circulation flow path 40 (see FIG. 2 ) during the regeneration treatment by the regeneration device 6. The acidic electrolyzed water circulation pump 23 is provided in the water supply flow path 48 that communicates between the acidic electrolyzed water storage tank 19 and the first water intake 12.

The acidic electrolyzed water circulation pump 23 makes it possible to control the flow rate of acidic electrolyzed water flowing through the acidic electrolyzed water circulation flow path 40. For example, when the hydrogen ion generation rate in the electrolytic cell 9 is constant, increasing the flow rate of acidic electrolyzed water decreases the hydrogen ion concentration (increases pH). Conversely, decreasing the flow rate of acidic electrolyzed water increases the hydrogen ion concentration (decreases pH). In other words, by adjusting the flow rate of acidic electrolyzed water with the acidic electrolyzed water circulation pump 23, it is possible to adjust the hydrogen ion concentration in the acidic electrolyzed water supplied to the weakly acidic cation exchange resin 7. This makes it possible to supply hydrogen ions according to the state of the weakly acidic cation exchange resin 7, thereby improving the performance of the water softener 1.

The alkaline electrolyzed water circulation pump 24 is a device that circulates water through the alkaline electrolyzed water circulation flow path 44 (see Figure 2) during the regeneration process by the regeneration device 6. The alkaline electrolyzed water circulation pump 24 is provided in the water supply flow path 49 that connects the alkaline electrolyzed water storage tank 21 and the second water intake 16. The acidic electrolyzed water circulation pump 23 and the alkaline electrolyzed water circulation pump 24 are connected to the control unit 26 (described later) via wireless or wired communication so as to be able to communicate with each other.

The alkaline electrolyzed water circulation pump 24 makes it possible to control the flow rate of alkaline electrolyzed water flowing through the alkaline electrolyzed water circulation flow path 44. For example, when the hydroxide ion production rate in the electrolytic cell 9 is constant, increasing the flow rate of alkaline electrolyzed water decreases the hydroxide ion concentration. Conversely, decreasing the flow rate of alkaline electrolyzed water increases the hydroxide ion concentration. In other words, by adjusting the flow rate of alkaline electrolyzed water with the alkaline electrolyzed water circulation pump 24, the hydroxide ion concentration in the alkaline electrolyzed water supplied to the weakly basic anion exchange resin 8 can be adjusted. Therefore, hydroxide ions can be supplied according to the state of the weakly basic anion exchange resin 8, improving the performance of the water softener 1.

By providing the acidic electrolyzed water circulation pump 23 and the alkaline electrolyzed water circulation pump 24 independently of each other, rather than as a single pump, it becomes possible to individually set the flow rate of acidic electrolyzed water capable of supplying hydrogen ions suitable for regenerating the weakly acidic cation exchange resin 7, and the flow rate of alkaline electrolyzed water capable of supplying hydroxide ions suitable for regenerating the weakly basic anion exchange resin 8.

(Capture section)
The capture section 25 is provided in the second supply flow path 45 after the electrolytic bath 9 and before the second neutralization bath 4b.

The capture unit 25 separates solids contained in the alkaline electrolyzed water supplied from the electrolytic cell 9. The solids are reaction products precipitated in the cathode chamber 18 of the electrolytic cell 9 when hardness components in the alkaline electrolyzed water react with hydroxide ions generated by the cathode 15. For example, if the hardness component contained in the alkaline electrolyzed water is magnesium ions, magnesium hydroxide will be produced. If the solids precipitated during the regeneration process are not removed, they will accumulate in the neutralization cell 4, and the elution of hardness components from the solids will increase the hardness of the softened water during the water softening process, i.e., reduce the water softening performance.

Therefore, by separating the precipitates in the capture section 25, the inflow and accumulation of precipitates into the second neutralization tank 4b can be suppressed, and a decrease in water softening performance during the water softening process can be suppressed.

The capture unit 25 may take any form as long as it is capable of separating the reaction products with the hardness components contained in the alkaline electrolyzed water supplied from the electrolytic cell 9. Examples include a cartridge-type filter, a filtration layer using granular filter media, a cyclone-type solid-liquid separator, or a hollow fiber membrane.

(Shut-off valve)
A plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, on-off valves 71, and on-off valves 72) are provided in each flow path, and are switched between an "open" state and a "closed" state in each flow path. Furthermore, each of the plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, on-off valves 71, and on-off valves 72) is connected to a control unit 26 (described later) wirelessly or by wire so as to be able to communicate with the control unit 26.

(Control unit)
The control unit 26 controls the water softening treatment for softening raw water containing hardness components. The control unit 26 also controls the regeneration treatment of the weakly acidic cation exchange resin 7 in the water softening tank 3 and the weakly basic anion exchange resin 8 in the neutralization tank 4. The control unit 26 also controls the switching of the water softening treatment, regeneration treatment, and wastewater treatment in the water softening device 1. In this case, the control unit 26 controls the operations of the anode 11, the cathode 15, the acidic electrolyzed water circulation pump 23, the alkaline electrolyzed water circulation pump 24, the on-off valves 51 to 55, the on-off valves 61 to 66, the on-off valve 71, and the on-off valve 72, to switch between the water softening treatment, regeneration treatment, and wastewater treatment, and to execute each treatment.

(Acidic electrolyzed water circulation flow path, alkaline electrolyzed water circulation flow path)
Next, the acidic electrolyzed water circulation flow path 40 and the alkaline electrolyzed water circulation flow path 44 formed during the regeneration treatment of the water softener 1 will be described with reference to Fig. 2. Fig. 2 is a structural diagram showing the acidic electrolyzed water circulation flow path 40 and the alkaline electrolyzed water circulation flow path 44 of the water softener 1.

As shown in FIG. 2 , in the water softener 1, the first water intake 12 and the acidic electrolyzed water storage tank 19, which constitute the regeneration device 6, are connected by a water supply channel 48. The second water intake 16 and the alkaline electrolyzed water storage tank 21 are connected by a water supply channel 49. The first discharge port 13, the acidic electrolyzed water storage tank 19, the second discharge port 17, and the alkaline electrolyzed water storage tank 21 are connected by a first supply channel 41, a first recovery channel 43, a second supply channel 45, and a second recovery channel 47 to the channels 33, 30, 34, and 31, respectively, from the inlet 2 to the water intake 5. The channels 31 and 32 are bypass-connected by a first bypass channel 42. The channels 32 and 33 are bypass-connected by a second bypass channel 46. These channels constitute the acidic electrolyzed water circulation channel 40 and the alkaline electrolyzed water circulation channel 44, which will be described later.

The first supply flow path 41 is a flow path that supplies acidic electrolyzed water from the first water intake 12 to the second water softening tank 3b, and an on-off valve 63 is installed in this flow path. In other words, the water softening device 1 is equipped with the first supply flow path 41 that allows acidic electrolyzed water to be drawn from the first water intake 12 and sent downstream to the second water softening tank 3b.

The first bypass flow path 42 is a flow path that supplies acidic electrolyzed water from the second water softening tank 3b to the first water softening tank 3a, and an on-off valve 65 is installed in this flow path. In other words, the water softening device 1 is equipped with a first bypass flow path 42 that allows acidic electrolyzed water that has flowed through the second water softening tank 3b to be sent downstream of the first water softening tank 3a. By providing the first bypass flow path 42, the regeneration process can be carried out without flowing acidic electrolyzed water through the first neutralization tank 4a located between the first water softening tank 3a and the second water softening tank 3b.

The first recovery flow path 43 is a flow path that recovers the acidic electrolyzed water containing hardness components that has passed through the first water softening tank 3a into the acidic electrolyzed water storage tank 19, and an on-off valve 61 is installed in this flow path. In other words, the water softening device 1 is equipped with the first recovery flow path 43 that allows the upstream side of the acidic electrolyzed water storage tank 19 to be connected to the upstream side of the first water softening tank 3a.

The water supply flow path 48 supplies acidic electrolyzed water stored in the acidic electrolyzed water storage tank 19 from the first water intake 12 to the anode chamber 14 of the electrolytic cell 9 using the acidic electrolyzed water circulation pump 23, and an on-off valve 71 is installed in this flow path. In other words, the water softener 1 is equipped with a water supply flow path 48 that allows the downstream side of the acidic electrolyzed water storage tank 19 to be connected to the first water intake 12 provided in the electrolytic cell 9.

The second supply flow path 45 is a flow path that supplies alkaline electrolyzed water from the second discharge port 17 through the capture unit 25 to the second neutralization tank 4b, and an on-off valve 64 is installed in this flow path. In other words, the water softener 1 is equipped with the second supply flow path 45 that allows alkaline electrolyzed water to be drawn from the second discharge port 17 and sent downstream of the second neutralization tank 4b.

The second bypass flow path 46 is a flow path that supplies alkaline electrolyzed water from the second neutralization tank 4b to the first neutralization tank 4a, and an on-off valve 66 is installed in this flow path. In other words, the water softener 1 is equipped with the second bypass flow path 46 that allows alkaline electrolyzed water that has flowed through the second neutralization tank 4b to be sent downstream of the first neutralization tank 4a.

The second recovery flow path 47 is a flow path that recovers the alkaline electrolyzed water that has passed through the first neutralization tank 4a to the alkaline electrolyzed water storage tank 21, and an on-off valve 62 is installed in this flow path. In other words, the water softener 1 is equipped with the second recovery flow path 47 that allows the upstream side of the alkaline electrolyzed water storage tank 21 to be connected to the upstream side of the first neutralization tank 4a.

The water supply flow path 49 supplies acidic electrolyzed water stored in the alkaline electrolyzed water storage tank 21 from the second water intake 16 to the cathode chamber 18 of the electrolytic cell 9 using the alkaline electrolyzed water circulation pump 24, and an on-off valve 72 is installed in this flow path. In other words, the water softening device 1 is equipped with a water supply flow path 49 that allows the downstream side of the alkaline electrolyzed water storage tank 21 to be connected to the second water intake 16 provided in the electrolytic cell 9.

As shown in Figure 2 (white arrow), the acidic electrolyzed water circulation flow path 40 is a flow path through which water delivered from the acidic electrolyzed water storage tank 19 by the acidic electrolyzed water circulation pump 23 flows through the electrolytic cell 9, the second water softening tank 3b, and the first water softening tank 3a, and then returns to the acidic electrolyzed water storage tank 19. More specifically, the acidic electrolyzed water circulation flow path 40 is a flow path through which water delivered from the acidic electrolyzed water storage tank 19 by the acidic electrolyzed water circulation pump 23 circulates through the water supply flow path 48, the first water intake 12, the anode chamber 14, the first discharge port 13, the first supply flow path 41, the on-off valve 63, the second water softening tank 3b, the first bypass flow path 42, the on-off valve 65, the first water softening tank 3a, the first recovery flow path 43, the on-off valve 61, and the acidic electrolyzed water storage tank 19 in this order.

As shown in Figure 2 (black arrow), the alkaline electrolyzed water circulation flow path 44 is a flow path through which water delivered from the alkaline electrolyzed water storage tank 21 by the alkaline electrolyzed water circulation pump 24 flows through the electrolytic cell 9, the second neutralization cell 4b, and the first neutralization cell 4a, and returns to the alkaline electrolyzed water storage tank 21. More specifically, the alkaline electrolyzed water circulation flow path 44 is a flow path through which water delivered from the alkaline electrolyzed water storage tank 21 by the alkaline electrolyzed water circulation pump 24 flows through the water delivery flow path 49, the second water intake 16, the cathode chamber 18, the second discharge port 17, the second supply flow path 45, the capture unit 25, the on-off valve 64, the second neutralization cell 4b, the second bypass flow path 46, the on-off valve 66, the first neutralization cell 4a, the second recovery flow path 47, the on-off valve 62, and the alkaline electrolyzed water storage tank 21 in this order.

Here, we will explain the state of each flow path for circulating water in the acidic electrolyzed water circulation flow path 40 and the alkaline electrolyzed water circulation flow path 44.

An on-off valve 54 is installed in the flow path 33 downstream of the first supply flow path 41 and upstream of the first bypass flow path 42. By closing the on-off valve 54 and opening the on-off valve 63, the first supply flow path 41 is connected downstream of the second water softening tank 3b. This allows acidic electrolyzed water from the anode chamber 14 of the electrolytic cell 9 to be supplied to the second water softening tank 3b.

An on-off valve 52 is installed in flow path 31 downstream of the first bypass flow path 42 and upstream of the second recovery flow path 47. Furthermore, an on-off valve 53 is installed in flow path 32 downstream of the second bypass flow path 46 and upstream of the first bypass flow path 42. By closing on-off valves 52 and 53 and opening on-off valve 65, the first bypass flow path 42 is connected upstream of the second water softening tank 3b and downstream of the first water softening tank 3a. This allows acidic electrolyzed water that has flowed through the second water softening tank 3b to be supplied to the first water softening tank 3a.

An on-off valve 51 is installed in the flow path 30 downstream of the inlet 2 and upstream of the first recovery flow path 43. By closing the on-off valves 51 and 52 and opening the on-off valve 61, the first recovery flow path 43 is connected to the upstream side of the first water softening tank 3a. This allows the water softening device 1 to recover water (acidic electrolyzed water containing hardness components) that has flowed through the first water softening tank 3a and the second water softening tank 3b into the acidic electrolyzed water storage tank 19.

An on-off valve 54 is installed in the flow path 34 downstream of the second supply flow path 45 and upstream of the second bypass flow path 46. An on-off valve 55 is also installed in the flow path 34 upstream of the water intake 5 and downstream of the second neutralization tank 4b. By closing the on-off valves 54 and 55 and opening the on-off valve 64, the second supply flow path 45 is connected downstream of the second neutralization tank 4b. This allows alkaline electrolyzed water from the cathode chamber 18 of the electrolytic cell 9 to be supplied to the second neutralization tank 4b.

An on-off valve 53 is installed in flow path 32 downstream of the second bypass flow path 46 and upstream of the second water softening tank 3b. Furthermore, by closing on-off valves 52, 53, and 54 and opening on-off valve 66, the second bypass flow path 46 is connected downstream of the first neutralization tank 4a and upstream of the second neutralization tank 4b. This allows alkaline electrolyzed water that has flowed through the second neutralization tank 4b to be supplied to the first neutralization tank 4a.

Furthermore, by closing the on-off valve 52 and opening the on-off valve 62, the second recovery flow path 47 is connected upstream of the first neutralization tank 4a. This allows the water softener 1 to recover the water (alkaline electrolyzed water containing anions) that has flowed through the first neutralization tank 4a and the second neutralization tank 4b into the alkaline electrolyzed water storage tank 21.

In addition, an on-off valve 71 is installed in the water supply flow path 48 downstream of the acidic electrolyzed water storage tank 19 (between the acidic electrolyzed water storage tank 19 and the acidic electrolyzed water circulation pump 23). By closing the on-off valve 71, water can be stored in the acidic electrolyzed water storage tank 19. On the other hand, by opening the on-off valve 71, water can be supplied to the water supply flow path 48.

In addition, an on-off valve 72 is installed in the water supply flow path 49 downstream of the alkaline electrolyzed water storage tank 21 (between the alkaline electrolyzed water storage tank 21 and the alkaline electrolyzed water circulation pump 24). By closing the on-off valve 72, water can be stored in the alkaline electrolyzed water storage tank 21. On the other hand, by opening the on-off valve 72, water can be supplied to the water supply flow path 49.

In addition, by closing the on-off valves 51 and 55, the circulation of water to the acidic electrolyzed water circulation flow path 40 and the alkaline electrolyzed water circulation flow path 44 can be started, while by opening the on-off valves 51 and 55, the circulation of water to the acidic electrolyzed water circulation flow path 40 and the alkaline electrolyzed water circulation flow path 44 can be stopped.

(Water softening and regeneration treatment)
Next, the water softening process, regeneration process, and drainage process of the water softening device 1, starting from the regeneration process, will be described with reference to Fig. 3. Fig. 3 is a diagram showing the state of the water softening device 1 during operation.

In the water softening, regeneration, and wastewater treatment processes, the control unit 26 controls the on-off valves 51 to 55, on-off valves 61 to 66, on-off valves 71 and 72, the anode 11, the cathode 15, the acidic electrolyzed water circulation pump 23, and the alkaline electrolyzed water circulation pump 24, as shown in FIG. 3, to switch between their respective circulation and operating states. The control unit 26 includes a computer system with a processor and memory. The computer system functions as the control unit when the processor executes a program stored in the memory. While the program executed by the processor is pre-recorded in the memory of the computer system here, it may also be provided by recording it on a non-transitory recording medium such as a memory card, or via a telecommunications line such as the Internet.

Here, "ON" in Figure 3 indicates that the corresponding on-off valve is "open," the anode 11 and cathode 15 are energized, and the acidic electrolyzed water circulation pump 23 and alkaline electrolyzed water circulation pump 24 are operating. Blank spaces indicate that the corresponding on-off valve is "closed," the anode 11 and cathode 15 are not energized, and the acidic electrolyzed water circulation pump 23 and alkaline electrolyzed water circulation pump 24 are stopped.

(Recycling process)
First, the operation of the regeneration device 6 of the water softening device 1 during regeneration treatment will be described in order with reference to the "Regeneration" column in FIG.

In the water softening device 1, the water softening tank 3 filled with weakly acidic cation exchange resin 7 loses or loses its cation exchange capacity with continued use. That is, once all of the hydrogen ions, which are functional groups of the cation exchange resin, have been exchanged for calcium ions or magnesium ions, which are hardness components, ion exchange becomes impossible. When this happens, hardness components become contained in the treated water. For this reason, the water softening device 1 requires the regeneration process of the water softening tank 3 and neutralization tank 4 using the regeneration device 6.

During regeneration, when on-off valves 51 to 55 are closed and on-off valves 61 to 66, 71, and 72 are opened, an acidic electrolyzed water circulation flow path 40 and an alkaline electrolyzed water circulation flow path 44 are formed, as shown in Figure 2.

When the anode 11, cathode 15, acidic electrolyzed water circulation pump 23, and alkaline electrolyzed water circulation pump 24 are operated, the water stored in the acidic electrolyzed water storage tank 19 and the alkaline electrolyzed water storage tank 21 circulates through the acidic electrolyzed water circulation flow path 40 and the alkaline electrolyzed water circulation flow path 44, respectively.

At this time, acidic electrolyzed water generated in the anode chamber 14 of the electrolytic cell 9 flows through the first discharge port 13 and the first supply flow path 41 into the second water softening tank 3b, where it flows through the second weakly acidic cation exchange resin 7b. The acidic electrolyzed water that has flowed through the second water softening tank 3b then flows through the first bypass flow path 42 into the first water softening tank 3a, where it flows through the first weakly acidic cation exchange resin 7a. By passing the acidic electrolyzed water through the first and second weakly acidic cation exchange resins 7a and 7b, the cations (hardness components) adsorbed on the first and second weakly acidic cation exchange resins 7a and 7b undergo an ion exchange reaction with the protons contained in the acidic electrolyzed water. This regenerates the first and second weakly acidic cation exchange resins 7a and 7b. The acidic electrolyzed water that has flowed through the first weakly acidic cation exchange resin 7a, including the cations, then flows into the first recovery flow path 43. That is, the acidic electrolyzed water containing cations that has passed through the first weakly acidic cation exchange resin 7a and the second weakly acidic cation exchange resin 7b is recovered in the acidic electrolyzed water storage tank 19 via the first bypass flow path 42 and the first recovery flow path 43.

In this way, the acidic electrolyzed water circulation flow path 40 is configured to circulate acidic electrolyzed water from the downstream side of the second water softener 3b, which is located most downstream from the raw water inlet and has the second weakly acidic cation exchange resin 7b that adsorbs less hardness components, to the downstream side of the first water softener 3a, which is located upstream and has the first weakly acidic cation exchange resin 7a that adsorbs more hardness components than the second weakly acidic cation exchange resin 7b. In other words, the acidic electrolyzed water circulation flow path 40 is a flow path that circulates acidic electrolyzed water delivered from the electrolytic cell 9 through the second water softener 3b, then sends it to the first water softener 3a via the first bypass flow path 42, flows through the first water softener 3a, and is collected in the acidic electrolyzed water storage tank 19, and then flows into the electrolytic cell 9 through the first water intake 12. The acidic electrolyzed water circulation flow path 40 also includes a path through which the acidic electrolyzed water delivered from the electrolytic cell 9 is introduced into the first and second softening tanks 3a and 3b from the downstream side of the first and second softening tanks 3a and 3b, and discharged from the upstream side, where a greater amount of hardness components are adsorbed than the downstream side of the softening tank 3. Note that the "downstream side" refers to the downstream side of the flow path during the water softening process.

In addition, since the acidic electrolyzed water circulation flow path 40 is a flow path independent of the alkaline electrolyzed water circulation flow path 44, mixing of the acidic electrolyzed water and the alkaline electrolyzed water is suppressed.

Alkaline electrolyzed water produced in the cathode chamber 18 of the electrolytic cell 9 is delivered from the second outlet 17 through the second supply flow path 45 and the capture unit 25 to the second neutralization cell 4b, where it flows through the second weakly basic anion exchange resin 8b. The alkaline electrolyzed water that has flowed through the second neutralization cell 4b flows through the second bypass flow path 46, is delivered to the first neutralization cell 4a, and flows through the first weakly basic anion exchange resin 8a. By passing alkaline electrolyzed water through the first and second weakly basic anion exchange resins 8a and 8b, anions adsorbed on the first and second weakly basic anion exchange resins 8a and 8b undergo ion exchange reactions with hydroxide ions contained in the alkaline electrolyzed water. This regenerates the first and second weakly basic anion exchange resins 8a and 8b. After that, the alkaline electrolyzed water that has passed through the second weakly basic anion exchange resin 8b contains anions and flows into the second recovery flow path 47. That is, the alkaline electrolyzed water that has passed through the first weakly basic anion exchange resin 8a and the second weakly basic anion exchange resin 8b and contains anions is recovered in the alkaline electrolyzed water storage tank 21 via the second bypass flow path 46 and the second recovery flow path 47.

In this way, the alkaline electrolyzed water circulation flow path 44 is configured to allow alkaline electrolyzed water to flow from the downstream side of the second neutralization tank 4b, which is located most downstream from the raw water inlet and has the second weakly basic anion exchange resin 8b with a small amount of adsorbed anions, to flow into the downstream side of the first neutralization tank 4a, which is located upstream and has the first weakly basic anion exchange resin 8a with a larger amount of adsorbed anions than the second weakly basic anion exchange resin 8b. In other words, the alkaline electrolyzed water circulation flow path 44 is a flow path through which alkaline electrolyzed water delivered from the electrolytic cell 9 flows through the second neutralization tank 4b, then sends it to the first neutralization tank 4a via the second bypass flow path 46, flows through the first neutralization tank 4a, is collected in the alkaline electrolyzed water storage tank 21, and then flows into the electrolytic cell 9 from the second water intake 16. The alkaline electrolyzed water storage tank 21 also has a path through which alkaline electrolyzed water delivered from the electrolytic tank 9 is introduced into the first neutralization tank 4a and the second neutralization tank 4b from the downstream side of the first neutralization tank 4a and the second neutralization tank 4b, and discharged from the upstream side, where a greater amount of anions are adsorbed than the downstream side of each neutralization tank. Note that the "downstream side" refers to the downstream side of the flow path during water softening treatment.

In addition, since the alkaline electrolyzed water circulation flow path 44 is a flow path independent of the acidic electrolyzed water circulation flow path 40, mixing of the acidic electrolyzed water and the alkaline electrolyzed water is suppressed.

When the regeneration process is completed, the water softener 1 stops the operation of the anode 11, cathode 15, acidic electrolyzed water circulation pump 23, and alkaline electrolyzed water circulation pump 24. The regeneration process may be completed after a certain time (e.g., 7 hours) from the start of the regeneration process (when the anode 11 and cathode 15 start operating).

(Water softening treatment)
Next, the operation of the water softening device 1 during water softening treatment will be described with reference to the "water softening" section of FIG.

As shown in FIG. 3, in the water softening device 1, during the water softening process (softening water), on-off valves 51 to 54 are open, and on-off valve 55 installed at the water intake 5 is opened. This allows city water (raw water containing hardness components) from the outside to flow through the water softening tank 3 and the neutralization tank 4, allowing the water softener 1 to extract softened water (neutral soft water) from the water intake 5. At this time, on-off valves 61 to 66, on-off valve 71, and on-off valve 72 are all closed. Furthermore, the anode 11, cathode 15, acidic electrolyzed water circulation pump 23, and alkaline electrolyzed water circulation pump 24 are also stopped.

Specifically, as shown in FIG. 1, in the water softening process, raw water is supplied from the inlet 2 through the flow path 30 to the first water softening tank 3a under the pressure of city water. The raw water then flows through the first weakly acidic cation exchange resin 7a provided within the first water softening tank 3a. The first weakly acidic cation exchange resin 7a adsorbs cations, which are hardness components in the raw water, and releases protons (ion exchange occurs). The raw water is then softened by removing the cations. The softened water contains many protons that have been exchanged with the hardness components and released, resulting in acidic water with a low pH. The softened water then flows through the flow path 31 and enters the first neutralization tank 4a. In the first neutralization tank 4a, the first weakly basic anion exchange resin 8a adsorbs the protons contained in the softened water. In other words, protons are removed from the water softened in the first water softening tank 3a, raising the pH and neutralizing it. Therefore, the water softening process in the second water softening tank 3b proceeds more easily than if water softened in the first water softening tank 3a were directly softened in the second water softening tank 3b. The water neutralized in the first neutralization tank 4a then flows through the flow path 32 and into the second water softening tank 3b. In the second water softening tank 3b, the second weakly acidic cation exchange resin 7b adsorbs cations, which are hardness components, and releases protons. In other words, the water that flows into the second water softening tank 3b is softened and becomes soft water. The proton-containing softened water flows through the flow path 33 and flows into the second neutralization tank 4b. In the second neutralization tank 4b, the second weakly basic anion exchange resin 8b adsorbs protons contained in the softened water. In other words, as protons are removed from the soft water, the lowered pH rises, turning it into neutral soft water that can be used for domestic purposes. The neutral soft water flows through the flow path 34 and can be taken out from the water intake 5.

The water softening device 1 then performs the regeneration process when the time period specified by the control unit 26 arrives or when the water softening process exceeds a certain period of time.

In this way, the water softening device 1 repeatedly performs water softening and regeneration processes.

As described above, the water softening device 1 according to the first embodiment can provide the following benefits:

(1) The water softening device 1 comprises a water softening tank 3, a neutralization tank 4, and an electrolytic tank 9. The water softening tank 3 softens raw water containing hardness components using a weakly acidic cation exchange resin 7. The neutralization tank 4 neutralizes the pH of the softened water that has passed through the water softening tank 3 using a weakly basic anion exchange resin 8. The electrolytic tank 9 produces acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 7 and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin 8. The electrolytic tank 9 has a first outlet 13 for sending the acidic electrolyzed water to the water softening tank 3, a first water intake 12 for taking in water that has passed through the water softening tank 3, a second outlet 17 for sending alkaline electrolyzed water to the neutralization tank 4, and a second water intake 16 for taking in water that has passed through the neutralization tank 4. The water softener 1 is configured to have an acidic electrolyzed water circulation flow path 40 that circulates acidic electrolyzed water through the electrolytic cell 9, first outlet 13, water softening cell 3, and first water intake 12 in that order, and an alkaline electrolyzed water circulation flow path 44 that circulates alkaline electrolyzed water through the electrolytic cell 9, second outlet 17, neutralization cell 4, and second water intake 16 in that order.

As a result, during the regeneration process, acidic electrolyzed water flows through the acidic electrolyzed water circulation flow path 40, and alkaline electrolyzed water flows through the alkaline electrolyzed water circulation flow path 44, preventing mixing of the acidic electrolyzed water and alkaline electrolyzed water. Therefore, even after the regeneration of one ion exchange resin is complete, acidic electrolyzed water with an acidic pH flows through the acidic electrolyzed water circulation flow path 40, and alkaline electrolyzed water with an alkaline pH flows through the alkaline electrolyzed water circulation flow path 44, preventing a decrease in the regeneration efficiency of the other ion exchange resin.

(2) In the water softening device 1, the electrolytic cell 9 is configured to include an anode chamber 14 housing an anode 11, a cathode chamber 18 housing a cathode 15, and a diaphragm 10 disposed between the anode chamber 14 and the cathode chamber 18. The electrolytic cell 9 generates acidic electrolyzed water in the anode chamber 14 and alkaline electrolyzed water in the cathode chamber 18.

With this configuration, the anode chamber 14 and cathode chamber 18 of the electrolytic cell 9 are separated by the diaphragm 10, making it possible to suppress the neutralization reaction between protons and hydroxide ions caused by mixing of acidic electrolyzed water and alkaline electrolyzed water. This makes it possible to suppress a decrease in the regeneration performance of the weakly acidic cation exchange resin 7 and the weakly basic anion exchange resin 8.

(3) The water softener 1 is configured to include an acidic electrolyzed water circulation pump 23 provided in the acidic electrolyzed water circulation flow path 40 and an alkaline electrolyzed water circulation pump 24 provided in the alkaline electrolyzed water circulation flow path 44.

This configuration makes it possible to control the flow rate of acidic electrolyzed water in the acidic electrolyzed water circulation flow path 40 and the flow rate of alkaline electrolyzed water in the alkaline electrolyzed water circulation flow path 44. During the regeneration process, the flow rate of acidic electrolyzed water affects the regeneration performance of the weakly acidic cation exchange resin 7, and the flow rate of alkaline electrolyzed water affects the regeneration performance of the weakly basic anion exchange resin 8. Therefore, by controlling the flow rate of acidic electrolyzed water in the acidic electrolyzed water circulation flow path 40 to a constant value using the acidic electrolyzed water circulation pump 23 and the flow rate of alkaline electrolyzed water in the alkaline electrolyzed water circulation flow path 44 to a constant value using the alkaline electrolyzed water circulation pump 24, it becomes possible to maintain constant regeneration performance of the weakly acidic cation exchange resin and the weakly basic anion exchange resin.

(4) The water softener 1 is configured to include an acidic electrolyzed water storage tank 19 located downstream of the water softener tank 3 and upstream of the first water intake 12 in the acidic electrolyzed water circulation flow path 40.

With this configuration, by storing acidic electrolyzed water in the acidic electrolyzed water storage tank 19, it is possible to control the total amount of acidic electrolyzed water circulating within the acidic electrolyzed water circulation flow path 40.

(5) The water softener 1 is configured to include an alkaline electrolyzed water storage tank 21 located downstream of the neutralization tank 4 and upstream of the second water intake 16 in the alkaline electrolyzed water circulation flow path 44.

With this configuration, by storing alkaline electrolyzed water in the alkaline electrolyzed water storage tank 21, it is possible to control the total amount of alkaline electrolyzed water circulating through the alkaline electrolyzed water circulation flow path 44.

(6) The water softener 1 is configured to include a capture unit 25 that separates solids from the alkaline electrolyzed water, and is provided in the alkaline electrolyzed water circulation flow path 44 downstream of the second discharge port 17 and upstream of the neutralization tank 4.

This configuration makes it possible to separate solids generated during the production of alkaline electrolyzed water. During the regeneration process, hardness components in the alkaline electrolyzed water may react with hydroxide ions generated by the cathode 15 of the electrolytic cell 9, resulting in the precipitation of solids (such as magnesium hydroxide). If these solids derived from the hardness components contained in the alkaline electrolyzed water are not removed, they will accumulate in the neutralization cell 4, and the elution of hardness components will increase the hardness of the softened water during the water softening process, thereby reducing water softening performance. Therefore, by providing a configuration with a capture unit 25, solids generated during the production of alkaline electrolyzed water can be separated upstream of the neutralization cell 4, preventing the inflow and accumulation of solids in the neutralization cell 4 and reducing performance degradation during the water softening process.

(7) In the water softening device 1, when the weakly acidic cation exchange resin 7 is regenerated, the acidic electrolyzed water discharged from the first discharge port 13 flows downstream into the water softening tank 3.

With this configuration, during regeneration, acidic electrolyzed water discharged from the anode chamber 14 of the electrolytic cell 9 flows into the water softener tank 3 from the downstream side, where less hardness components are adsorbed, to regenerate the water softener tank 3. During regeneration of the weakly acidic cation exchange resin 7 on the downstream side, less hydrogen ions are consumed in the acidic electrolyzed water than on the upstream side, preventing a decrease in the hydrogen ion concentration of the acidic electrolyzed water. This prevents the hardness components contained in the acidic electrolyzed water from the downstream side from being re-adsorbed on the upstream side. This prevents a decrease in the regeneration efficiency of the water softener tank 3 and shortens the regeneration time.

(8) In the water softening device 1, when the weakly basic anion exchange resin 8 is regenerated, the alkaline electrolyzed water discharged from the second discharge port 17 flows downstream into the neutralization tank 4.

With this configuration, during regeneration, alkaline electrolyzed water discharged from the cathode chamber 18 of the electrolytic cell 9 flows into the neutralization cell 4 from the downstream side, where the amount of adsorbed anion components is smaller, to regenerate the neutralization cell 4. During regeneration of the weakly basic anion exchange resin 8 on the downstream side, less hydroxide ions are consumed in the alkaline electrolyzed water compared to the upstream side, so a decrease in the hydroxide ion concentration of the alkaline electrolyzed water can be suppressed. Therefore, it is possible to suppress the re-adsorption of anions contained in the alkaline electrolyzed water from the downstream side on the upstream side. Therefore, it is possible to suppress a decrease in the regeneration efficiency of the neutralization cell 4 and shorten the regeneration time.

(9) The water softening tank 3 of the water softening device 1 has a first water softening tank 3a and a second water softening tank 3b, and the neutralization tank 4 has a first neutralization tank 4a and a second neutralization tank 4b. When raw water is softened, it flows through the first water softening tank 3a, the first neutralization tank 4a, the second water softening tank 3b, and the second neutralization tank 4b in this order.

With this configuration, raw water containing hardness components flows out of the first water softening tank 3a before the pH of the raw water drops due to the softening process in the first water softening tank 3a. It is neutralized in the first neutralization tank 4a, softened in the second water softening tank 3b, and neutralized in the second neutralization tank 4b. Therefore, compared to when the water softening tank 3 and neutralization tank 4 are each configured as separate units, the pH drop (i.e., acidification) of the water flowing through the water softening tank 3 can be suppressed, making it easier for hardness components to exchange with protons held by the weakly acidic cation exchange resin in the water softening tank 3 (particularly the second water softening tank 3b). This makes it possible to improve water softening performance.

(10) In the water softening device 1, during the regeneration process for regenerating the weakly acidic cation exchange resin 7, the acidic electrolyzed water discharged from the anode chamber 14 of the electrolytic cell 9 flows through the second water softening cell 3b and then through the first water softening cell 3a.

With this configuration, during regeneration, acidic electrolyzed water discharged from the anode chamber 14 of the electrolytic cell 9 flows into the second water softening cell 3b, which adsorbs fewer hardness components than the first water softening cell 3a. The acidic electrolyzed water containing hardness components is then discharged from the second water softening cell 3b to the first water softening cell 3a. During regeneration of the second weakly acidic cation exchange resin 7b in the second water softening cell 3b, less protons are consumed in the acidic electrolyzed water than in the first water softening cell 3a. This reduces the reduction in proton concentration compared to regeneration of the first water softening cell 3a. Therefore, acidic electrolyzed water containing a large amount of protons flows into the first water softening cell 3a, preventing re-adsorption of hardness components in the first water softening cell 3a. This reduces the decrease in regeneration efficiency and shortens the regeneration time.

(11) In the water softening device 1, during the regeneration process for regenerating the weakly basic anion exchange resin 8, the alkaline electrolyzed water discharged from the cathode chamber 18 of the electrolytic cell 9 flows through the second neutralization cell 4b and then through the first neutralization cell 4a.

With this configuration, during regeneration treatment, alkaline electrolyzed water discharged from the cathode chamber 18 of the electrolytic cell 9 flows into the second neutralization cell 4b, which adsorbs a smaller amount of anions than the first neutralization cell 4a, and alkaline electrolyzed water containing anions is discharged from the second neutralization cell 4b to the first neutralization cell 4a. During regeneration of the second weakly basic anion exchange resin 8b in the second neutralization cell 4b, hydroxide ions in the alkaline electrolyzed water are consumed less than in the first neutralization cell 4a, so the reduction in hydroxide ion concentration can be suppressed compared to regeneration of the first neutralization cell 4a. Therefore, alkaline electrolyzed water containing a large amount of hydroxide ions flows into the first neutralization cell 4a, and re-adsorption of anions in the first neutralization cell 4a can be suppressed. Therefore, a decrease in regeneration treatment efficiency can be suppressed, and the regeneration time can be shortened.

(12) In the water softening device 1, the first water softening tank 3a and the second water softening tank 3b are configured so that the flow path length, flow path cross-sectional area, volume of resin filled in the water softening tank 3, and type of resin filled in the water softening tank 3 are all the same.

With this configuration, the first water softening tank 3a and the second water softening tank 3b can be constructed using the same materials, thereby reducing the cost of the water softening device 1.

(13) In the water softening device 1, the first neutralization tank 4a and the second neutralization tank 4b are configured so that the flow path length, flow path cross-sectional area, volume of resin filled in the neutralization tank 4, and type of resin filled in the neutralization tank 4 are all the same.

With this configuration, the first neutralization tank 4a and the second neutralization tank 4b can be constructed using the same materials, thereby reducing the cost of the water softening device 1.

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

In the water softening device 1 according to the first embodiment, there are two water softening tanks 3 and two neutralization tanks 4, but this is not limited to this. For example, there may be one of each. This simplifies the device configuration. Also, for example, there may be three of each, or even more. This increases the number of times water softening and neutralization are alternated during the water softening process, further improving water softening performance.

In addition, in the water softening device 1 according to the first embodiment, the flow path length and flow path cross-sectional area of the first water softening tank 3a and the second water softening tank 3b are the same, but this is not limited to this. For example, the flow path length or the flow path cross-sectional area may be different, or both the flow path length and the flow path cross-sectional area may be different. Even in this case, the same effect as in the first embodiment can be obtained.

In addition, in the water softener 1 according to the first embodiment, the volumes of the first weakly acidic cation exchange resin 7a packed in the first water softening tank 3a and the second weakly acidic cation exchange resin 7b packed in the second water softening tank 3b are the same, but this is not limited to this. For example, the volumes of the first weakly acidic cation exchange resin 7a and the second weakly acidic cation exchange resin 7b may be different, or different types of weakly acidic cation exchange resins 7 may be used. This allows the water softening performance to be adjusted, resulting in a water softener 1 with water softening performance suited to the purpose.

In addition, in the water softening device 1 according to the first embodiment, the flow path length and flow path cross-sectional area of the first neutralization tank 4a and the second neutralization tank 4b are the same, but this is not limited to this. For example, the flow path length or the flow path cross-sectional area may be different, or both the flow path length and the flow path cross-sectional area may be different. Even in this case, the same effect as in the first embodiment can be obtained.

In addition, in the water softener 1 according to the first embodiment, the first weakly basic anion exchange resin 8a packed in the first neutralization tank 4a and the second weakly basic anion exchange resin 8b packed in the second neutralization tank 4b are assumed to have the same volume, but this is not limited to this. For example, the volumes of the first weakly basic anion exchange resin 8a and the second weakly basic anion exchange resin 8b may be different, or different types of weakly basic anion exchange resins 8 may be used. However, the volume of the second weakly basic anion exchange resin 8b packed in the second neutralization tank 4b need only be sufficient to adsorb the hydrogen ions released from the second water softening tank 3b and convert the acidic softened water flowing from the second water softening tank 3b into neutral softened water. This allows the water softening performance to be adjusted, resulting in a water softener 1 with water softening performance tailored to the intended purpose.

In addition, in the water softening device 1 according to the first embodiment, the acidic electrolyzed water is passed through the second water softening tank 3b and then the first water softening tank 3a, but this is not limited to this. For example, the acidic electrolyzed water may be passed through the first water softening tank 3a and then the second water softening tank 3b. Furthermore, in the water softening device 1 according to the first embodiment, the acidic electrolyzed water is passed through the water softening tank 3 from the downstream side, but it may be passed through the upstream side. This also allows the regeneration process of the water softening tank 3 to be performed.

In addition, in the water softening device 1 according to the first embodiment, the acidic electrolyzed water is circulated through the second water softening tank 3b and then the first water softening tank 3a in this order, but this is not limited to this. For example, it is also possible to perform the regeneration process on independent flow paths using a first regeneration device and a second regeneration device that have the same functions as the regeneration device 6. This allows the regeneration process of the first water softening tank 3a and the second water softening tank 3b to be carried out independently, thereby shortening the time required for the regeneration process.

In addition, in the water softening device 1 according to the first embodiment, alkaline electrolyzed water is passed through the second neutralization tank 4b and then the first neutralization tank 4a, but this is not limited to this. For example, alkaline electrolyzed water may be passed through the first neutralization tank 4a and then the second neutralization tank 4b. Furthermore, in the water softening device 1 according to the first embodiment, acidic electrolyzed water is passed through the neutralization tank 4 from the downstream side, but it may be passed through the upstream side. This also allows the regeneration process of the neutralization tank 4 to be performed.

In addition, in the water softening device 1 according to the first embodiment, the alkaline electrolyzed water is circulated through the second neutralization tank 4b and then the first neutralization tank 4a in this order, but this is not limited to this. For example, it is also possible to perform the regeneration process through independent flow paths using a first regeneration device and a second regeneration device that have the same functions as the regeneration device 6. This allows the regeneration process of the first neutralization tank 4a and the second neutralization tank 4b to be carried out independently, thereby shortening the time required for the regeneration process.

Furthermore, in the water softening device 1 according to the first embodiment, the regeneration process is executed when a time period specified by the control unit 26 is reached or when the water softening process has continued for a certain period of time. However, this is not limited to this. For example, an ion concentration detector may be provided downstream of the second neutralization tank 4b and upstream of the on-off valve 55, and the ion concentration detector may constantly detect the ion concentration (e.g., hardness component concentration) of the softened water flowing through the flow path 34. The regeneration process may be executed not only when a time period specified by the control unit 26 is reached or when the water softening process has continued for a certain period of time, but also when the ion concentration exceeds a preset reference value. This allows the execution of the regeneration process to be determined based on the ion concentration of the water after it has passed through the second neutralization tank 4b. This allows the state of the weakly acidic cation exchange resin 7 in the water softening tank 3 to be more accurately determined, enabling the regeneration of the weakly acidic cation exchange resin 7 and the weakly basic anion exchange resin 8 at the appropriate time.

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

REFERENCE SIGNS LIST 1 Water softening device 2 Inlet 3 Water softening tank 3a First water softening tank 3b Second water softening tank 4 Neutralization tank 4a First neutralization tank 4b Second neutralization tank 5 Water intake 6 Regeneration device 7 Weakly acidic cation exchange resin 7a First weakly acidic cation exchange resin 7b Second weakly acidic cation exchange resin 8 Weakly basic anion exchange resin 8a First weakly basic anion exchange resin 8b Second weakly basic anion exchange resin 9 Electrolytic cell 10 Diaphragm 11 Anode 12 First water intake 13 First discharge port 14 Anode chamber 15 Cathode 16 Second water intake 17 Second discharge port 18 Cathode chamber 19 Acidic electrolyzed water storage tank 20 Air vent valve 21 Alkaline electrolyzed water storage tank 22 Air vent valve 23 Acidic electrolyzed water circulation pump 24 Alkaline electrolyzed water circulation pump 25 Capture unit 26 Control unit 30 Flow path 31 Flow path 32 Flow path 33 Flow path 34 Flow path 40 Acidic electrolyzed water circulation path 41 First supply path 42 First bypass path 43 First recovery path 44 Alkaline electrolyzed water circulation path 45 Second supply path 46 Second bypass path 47 Second recovery path 48 Water supply path 49 Water supply path 51 On-off valve 52 On-off valve 53 On-off valve 54 On-off valve 55 On-off valve 61 On-off valve 62 On-off valve 63 On-off valve 64 On-off valve 65 On-off valve 66 On-off valve 71 On-off valve 72 On-off valve

Claims (10)

a water softening tank that softens raw water containing hardness components using a weakly acidic cation exchange resin;
a neutralization tank for neutralizing the softened water that has passed through the water softening tank with a weakly basic anion exchange resin;
an electrolytic cell for producing acidic electrolyzed water for regenerating the weakly acidic cation exchange resin and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin;
Equipped with
The electrolytic cell comprises:
a first outlet for sending the acidic electrolyzed water to the water softening tank;
a first water intake for taking in water that has passed through the water softening tank;
a second outlet for sending the alkaline electrolyzed water to the neutralization tank;
a second water intake for taking in water that has passed through the neutralization tank;
an acidic electrolyzed water circulation flow path for circulating the acidic electrolyzed water through the electrolytic bath, the first outlet, the water softening bath, and the first water intake in this order;
an alkaline electrolyzed water circulation flow path for circulating the alkaline electrolyzed water through the electrolytic bath, the second outlet, the neutralization bath, and the second intake port in this order ;
The water softening device is characterized in that the alkaline electrolyzed water circulation flow path is provided with a capture unit for separating solids in the alkaline electrolyzed water, located downstream of the second discharge port and upstream of the neutralization tank . The electrolytic cell comprises:
an anode chamber containing an anode;
a cathode chamber containing a cathode;
a diaphragm disposed between the anode chamber and the cathode chamber;
and
2. The water softening device according to claim 1, wherein the acidic electrolyzed water is produced in the anode chamber, and the alkaline electrolyzed water is produced in the cathode chamber. an acidic electrolyzed water circulation pump provided in the acidic electrolyzed water circulation flow path;
an alkaline electrolyzed water circulation pump provided in the alkaline electrolyzed water circulation flow path;
2. The water softening device according to claim 1 , further comprising: 2. The water softening apparatus according to claim 1 , further comprising an acidic electrolyzed water storage tank provided in the acidic electrolyzed water circulation flow path downstream of the water softening tank and upstream of the first water intake. The water softening device according to claim 1 , further comprising an alkaline electrolyzed water storage tank provided in the alkaline electrolyzed water circulation flow path downstream of the neutralization tank and upstream of the second water intake. 2. The water softening device according to claim 1 , wherein the acidic electrolyzed water discharged from the first discharge port flows from the downstream side of the water softening tank when the weakly acidic cation exchange resin is regenerated. 2. The water softening device according to claim 1 , wherein when the weakly basic anion exchange resin is regenerated, the alkaline electrolyzed water discharged from the second discharge port flows from the downstream side of the neutralization tank. 2. The water softening apparatus according to claim 1, wherein the water softening tank has a first water softening tank and a second water softening tank, and the neutralization tank has a first neutralization tank and a second neutralization tank, and when the raw water is softened, the raw water flows through the first water softening tank, the first neutralization tank, the second water softening tank, and the second neutralization tank in this order. 9. The water softening device according to claim 8, wherein, when the weakly acidic cation exchange resin is regenerated, the acidic electrolyzed water discharged from the first discharge port flows through the second water softening tank and then flows through the first water softening tank. The water softening device according to claim 8, characterized in that, when regenerating the weakly basic anion exchange resin, the alkaline electrolyzed water discharged from the second discharge port flows through the second neutralization tank and then flows through the first neutralization tank.