JP7603209B2 - 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 method of regenerating cation exchange resins without using salt is known in which the cation exchange resins are regenerated using acidic electrolyzed water generated by electrolysis (see, for example, Patent Document 1). Weakly acidic cation exchange resins have protons at the ends of their functional groups, and soften the raw water by exchanging hardness components (e.g., calcium ions, magnesium ions) in the raw water with hydrogen ions. The hydrogen ions in the water softened by the weakly acidic cation exchange resin are neutralized by being adsorbed by the weakly basic anion exchange resin provided downstream of the weakly acidic cation exchange resin. In conventional water softeners, a method of regenerating weakly basic anion exchange resins using alkaline electrolyzed water generated by electrolysis is known in which the weakly basic anion exchange resins are regenerated (see, for example, Patent Document 2).

JP 2011-30973 A JP 2010-142674 A

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

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

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

The present invention provides a water softening device that can suppress the deterioration of water softening performance caused by hardness components released from the water softening tank during the regeneration process of the water softening tank.

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 configuration diagram showing a circulation flow path of the water softening device. FIG. 3 is a diagram showing the configuration of a cleaning flow path of the water softening device. FIG. 4 is a diagram showing the state of the water softening device during operation. FIG. 5 is a conceptual diagram showing the configuration of a water softening device according to a second embodiment of the present invention. FIG. 6 is a conceptual diagram showing the configuration of a water softening device according to a third embodiment of the present invention.

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

With this configuration, when regenerating the water softening tank and neutralization tank, the separation section can separate the precipitates (precipitates caused by hardness components contained in the water introduced into the electrolytic tank) contained in the alkaline electrolytic water that has passed through the electrolytic tank, reducing the inflow of precipitates into the neutralization tank. Therefore, when resuming water softening after the regeneration process is completed, it is possible to suppress the occurrence of the phenomenon seen in conventional water softening devices in which precipitates that have flowed into the neutralization tank react with hydrogen ions released from the water softening tank to become hardness components, reducing the deterioration of water softening performance due to the dissolution of precipitates.

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

In addition, in the water softener according to the present invention, the control unit may be configured to control the end of polarity reversal of the electrolytic cell when the ion concentration determined based on the information on the ion concentration of the acidic electrolyzed water after polarity reversal that has flowed through the separation unit falls below a reference value. With this configuration, the end of polarity reversal can be controlled based on the ion concentration contained in the acidic electrolyzed water after polarity reversal. Therefore, it is possible to circulate the acidic electrolyzed water through the separation unit until the hardness components contained in the acidic electrolyzed water after flowing through the separation unit fall below a reference value, and cleaning of the separation unit (dissolution of separated precipitates) can be performed more reliably. Therefore, the frequency of maintenance of the separation unit can be further reduced, resulting in a water softener that can be used for a long period of time.

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

The following describes an embodiment of the present invention with reference to the drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention. Also, each figure described in the embodiment is a schematic diagram, and the ratio of the size and thickness of each component in each figure does not necessarily reflect the actual dimensional ratio.

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

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

The inlet 2 is connected to city water. The water softener 1 is capable of extracting softened water from the water intake 5 using the city water pressure.

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

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

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

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

Here, there is no particular limitation on the weak acid cation exchange resin 10, and a general-purpose one can be used, for example, one in which the exchange group is a carboxyl group (-COOH). In addition, the hydrogen ion ( H ⁺ ), which is the counter ion of the carboxyl group, may be replaced by a cation such as a metal ion or an ammonium ion ( NH ₄ ⁺ ).

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

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

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

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

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

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

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

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

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

In addition, in the electrolytic cell 12, the polarity change ends after a certain time (e.g., 5 minutes) has elapsed since the polarity change started.

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

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

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

(Separation section)
The separation unit 14 is provided in the second supply flow path 24a that communicates between the electrolytic cell 12 and the selection valve 19. The separation unit 14 separates precipitates contained in the alkaline electrolyzed water sent from the electrolytic cell 12. The precipitates are reaction products generated in the electrolytic cell 12 by the reaction of the alkaline electrolyzed water with the cation-containing hardness components released from the softening cell during the regeneration process of the softening cell. More specifically, the electrolysis of water is performed in the electrolytic cell 12, and acidic electrolyzed water is obtained at the anode side (electrode 13a) and passed through the first supply flow path 22a. The alkaline electrolyzed water containing anions (e.g., hydroxide ions) is obtained at the cathode side (electrode 13b) and passed through the second supply flow path 24a. During the electrolysis in the electrolytic cell 12, the hardness components (e.g., calcium ions, magnesium ions) released from the softening cell 3 during the regeneration process move to the cathode side. Since alkaline electrolyzed water is generated on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates. For example, when the hardness components are calcium ions, a reaction occurs in which calcium carbonate is generated or a reaction occurs in which calcium hydroxide is generated when the hardness components are mixed with the alkaline electrolyzed water. The precipitates derived from the hardness components are separated as precipitates in the separation section 14 provided on the second supply flow path 24a. By separating the precipitates derived from the hardness components in the separation section 14, it is possible to prevent the precipitates from flowing into the neutralization tank 4 and accumulating. Therefore, when the water softening process is resumed after the regeneration process is completed, the precipitates accumulated in the neutralization tank 4 react with the hydrogen ions released from the water softening tank 3 to form hardness components, and it is possible to prevent an increase in the hardness of the soft water discharged from the neutralization tank 4. During the regeneration process, the alkaline electrolyzed water from which the precipitate derived from the hardness components has been separated in the separation section 14 flows through the neutralization tank 4, is mixed with the acidic electrolyzed water, and is electrolyzed again in the electrolysis tank 12 to produce acidic electrolyzed water and alkaline electrolyzed water, which are respectively used for regeneration of the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11. At this time, the acidic electrolyzed water contains less hardness components than city water or the case without the separation section 14. In other words, by separating the precipitate in the separation section 14, the hardness of the acidic electrolyzed water is reduced, so that the hardness components flowing into the water softening tank 3 can be reduced, and the decrease in the regeneration efficiency of the weakly acidic cation exchange resin 10 can be suppressed.

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

The separation unit 14 may take any form as long as it is capable of separating the precipitates resulting from the reaction between the hardness components and the alkaline electrolyzed water. Examples of forms that may be used include a cartridge-type filter, a filtration layer using granular filter media, a cyclone-type solid-liquid separator, a hollow fiber membrane, etc.

A commonly used form of the separation section 14 is a cartridge-type filter. Cartridge-type filters can be depth filtration types such as thread-wound filters, surface filtration types such as pleated filters and membrane filters, or combinations of these.

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

The granular filter media used in the filtration layer is intended to capture and remove hardness components, but depending on the presence of particles with a surface potential that are adsorbed by the granular filter media, and ions in the raw water, it can also remove particles with a particle diameter of about 1 to 10 micrometers or chromaticity. The granular filter media can be filter sand or pellet-shaped fiber filter media, or any other filter media suitable for the object to be removed. The material of the granular filter media can be, for example, sand, anthracite, garnet, ceramics, granular activated carbon, iron oxyhydroxide, manganese sand, or any other material that settles in water and has a hardness that makes it difficult to deform under pressure. The particle diameter should be, for example, 0.3 to 5.0 mm, and the uniformity coefficient should be 1.2 to 2.0.

In addition, the multi-layer filtration method uses a mixture of multiple types of filter media with different specific gravities, and is a method of stacking particles of different sizes from the bottom up in order of small particles as layers to be filtered. In the multi-layer filtration method, particles with high specific gravity and small size are generally mixed with particles with low specific gravity and large size to form a multi-layer structure. The multi-layer filtration method is preferable because it has the advantages of high filtration efficiency per unit volume and low head loss compared to using a single type of filter media. As the granular filter media, for example, 0.3 mm of garnet, 0.6 mm of sand, and 1.0 mm of anthracite are mixed in a ratio of 2:1:1, and it is preferable to adjust the mixing ratio and particle size according to the particle characteristics of the turbidity.

(On-off valve and selection valve)
A plurality of on-off valves (on-off valves 27 to 34) are provided in each flow path, respectively, and switch between an "open" state and a "closed" state in each flow path. The selection valve 17 is provided in the first supply flow path 22, and determines the flow direction of the electrolytic water generated by electrolysis at the electrode 13a of the electrolytic cell 12. Specifically, the selection valve 17 switches between a flow state in which the electrolytic water generated by electrolysis at the electrode 13a flows through the first supply flow path 22 (first supply flow path 22a and first supply flow path 22b) to the water softener cell 3, and a flow path state in which the electrolytic water generated by electrolysis at the electrode 13a flows from the first supply flow path 22a to the first drainage port 16 via the first drainage flow path 37. The selection valve 19 is provided in the second supply flow path 24, and determines the flow direction of the electrolytic water generated by electrolysis at the electrode 13b of the electrolytic cell 12. Specifically, the selection valve 19 switches between a flow state in which the electrolytic water generated by electrolysis at the electrode 13b flows through the separation unit 14 and the second supply flow path 24 (the second supply flow path 24a and the second supply flow path 24b) to the neutralization tank 4, and a flow path state in which the electrolytic water generated by electrolysis at the electrode 13b flows from the second supply flow path 24a to the second drain outlet 18 via the separation unit 14 and the second drain flow path 38. In addition, the multiple on-off valves (on-off valves 27 to 34), the selection valve 17, and the selection valve 19 are each connected to a control unit 35 described later by wireless or wired communication.

(Drain)
The first drain outlet 16 and the second drain outlet 18 discharge the electrolyzed water (acidic electrolyzed water and alkaline electrolyzed water) flowing out of the electrolytic cell 12 to the outside of the apparatus when the separation section 14 is cleaned (when the separation section is cleaned) and when draining water following the cleaning of the separation section, which will be described later.

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

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

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

(Flow path)
Next, a description will be given of the circulation flow path 21 formed during the regeneration process of the water softening device 1 with reference to Fig. 2. Fig. 2 is a configuration diagram showing the circulation flow path 21 of the water softening device 1.

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

The first supply flow path 22 is a flow path that supplies acidic electrolyzed water from the electrolytic cell 12 to the water softening cell 3, and a selection valve 17 and an on-off valve 27 are installed in the flow path. The first supply flow path 22 is composed of a first supply flow path 22a that connects the electrolytic cell 12 and the selection valve 17, and a first supply flow path 22b that connects the selection valve 17 and the water softening cell 3. In other words, the water softening device 1 is equipped with a first supply flow path 22 that draws acidic electrolyzed water from the electrolytic cell 12 and can be sent to the upstream side of the water softening cell 3.

The first recovery flow path 23 is a flow path that recovers water containing hardness components that has passed through the water softening tank 3 to the water storage tank 15, and an on-off valve 28 is installed in the flow path. In other words, the water softening device 1 is equipped with the first recovery flow path 23 that allows the upstream side of the water storage tank 15 to be connected to the downstream side of the water softening tank 3.

The second supply flow path 24 is a flow path that supplies alkaline electrolyzed water from the electrolytic cell 12 to the neutralization cell 4 via the separation unit 14, and a selection valve 19 and an opening/closing valve 29 are installed in the flow path. The second supply flow path 24 is composed of a second supply flow path 24a that connects the electrolytic cell 12 and the selection valve 19, and a second supply flow path 24b that connects the selection valve 19 and the neutralization cell 4. In other words, the water softener 1 is provided with a second supply flow path 24 that separates precipitates derived from hardness components contained in the alkaline electrolyzed water drawn from the electrolytic cell 12 in the separation unit 14 and enables the alkaline electrolyzed water from which the precipitates have been separated to be sent upstream of the neutralization cell 4.

The second recovery flow path 25 is a flow path that recovers the water that has passed through the neutralization tank 4 to the water storage tank 15, and an on-off valve 30 is installed in the flow path. In other words, the water softening device 1 is equipped with the second recovery flow path 25 that allows the upstream side of the water storage tank 15 to be connected to the downstream side of the neutralization tank 4.

The circulation flow path 21 includes a first circulation flow path 21a through which water discharged from the water tank 15 by the water supply pump 20 flows through the water softening tank 3, and a second circulation flow path 21b through which water discharged from the water tank 15 by the water supply pump 20 flows through the neutralization tank 4.

As shown in FIG. 2 (white arrow), the first circulation flow path 21a is a flow path through which water sent from the water tank 15 by the water supply pump 20 flows through the electrolytic cell 12 and the water softener tank 3, and then circulates back to the water tank 15. More specifically, the first circulation flow path 21a is a flow path through which water sent from the water tank 15 by the water supply pump 20 flows and circulates through the water supply flow path 36, the electrolytic cell 12, the first supply flow path 22a, the selection valve 17, the first supply flow path 22b, the on-off valve 27, the water softener tank 3, the first recovery flow path 23, the on-off valve 28, and the water tank 15 in this order.

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

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

In addition, an on-off valve 32 is installed in the flow path 8 downstream of the first recovery flow path 23 and upstream of the second supply flow path 24b. By closing the on-off valve 32 and opening the on-off valve 28, the first recovery flow path 23 is connected in communication with the downstream side of the water softening tank 3. This allows the water softening device 1 to recover the water (acidic electrolyzed water containing hardness components) that has flowed through the water softening tank 3 into the water storage tank 15.

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

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

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

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

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

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

Next, referring to FIG. 3, we will explain the cleaning flow path 26 that is formed during the cleaning process of the water softener 1. FIG. 3 is a configuration diagram showing the cleaning flow path 26 of the water softener 1.

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

The first drainage flow path 37 is a flow path that drains water from the selection valve 17 to the first drain outlet 16. In other words, the water softening device 1 is equipped with a first drainage flow path 37 that draws water from the selection valve 17 to the first drain outlet 16 so that it can be discharged outside the device.

The second drainage flow path 38 is a flow path that drains water from the selection valve 19 to the second drain outlet 18. In other words, the water softening device 1 is equipped with a second drainage flow path 38 that draws water from the selection valve 19 to the second drain outlet 18 so that it can be discharged outside the device.

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

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

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

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

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

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

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

In the water softening device 1, the water softening tank 3 filled with the weakly acidic cation exchange resin 10 loses or loses its cation exchange capacity with continued use. In other words, after all of the hydrogen ions, which are the functional groups of the cation exchange resin, are exchanged with calcium ions or magnesium ions, which are hardness components, ion exchange is no longer possible. In this state, hardness components become contained in the treated water. For this reason, in the water softening device 1, it becomes necessary to carry out a regeneration process of the water softening tank 3 and neutralization tank 4 using the regeneration device 6.

Therefore, in the water softening device 1, the control unit 35 identifies a time period during which regeneration processing is possible once per predetermined period (e.g., once per day (24 hours)), and executes the regeneration processing.

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

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

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

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

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

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

At this time, by mixing acidic electrolyzed water containing cations (hardness components) with alkaline electrolyzed water containing anions, the hardness components react with the hydroxide ions contained in the alkaline electrolyzed water, producing precipitates. However, at least in the initial stages of the regeneration process, the amount of hydroxide ions contained in the alkaline electrolyzed water flowing in from the neutralization tank 4 is small compared to the amount of hardness components released from the water softener tank 3, so precipitates are unlikely to form. Therefore, the hardness components contained in the neutralized electrolyzed water are sent directly to the electrolytic tank 12.

The electrolytic water mixed in the water tank 15 is then passed through the water supply flow path 36 again to the electrolytic cell 12. The passed water is then electrolyzed again in the electrolytic cell 12.

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

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

Here, the acidic electrolyzed water electrolyzed again in the electrolytic cell 12 and the alkaline electrolyzed water electrolyzed again in the electrolytic cell 12 and from which the precipitate has been separated by the separation section 14 are used to regenerate the weakly acidic cation exchange resin 10 and the weakly basic anion exchange resin 11, respectively.

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

When the regeneration process is completed, the water softener 1 reverses the polarity of the electrode 13. In addition, the on-off valves 27, 28, and 29 are closed, the on-off valves 31 and 32 are opened, the water flow direction of the selection valve 17 is switched from the direction of the water softener tank 3 to the direction of the first drain outlet 16, and the water flow direction of the selection valve 19 is switched from the direction of the neutralization tank 4 to the direction of the second drain outlet 18, thereby moving to the cleaning process.

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

Next, the operation of the water softener 1 during cleaning will be explained with reference to the "During cleaning" section of Figure 4.

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

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

When the electrodes 13 of the electrolytic cell 12 and the water pump 20 are operated, raw water and electrolyzed water (acidic electrolyzed water, alkaline electrolyzed water) flow through the cleaning flow path 26.

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

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

When the cleaning process is completed, the water softener 1 stops polarity inversion of the electrode 13 and stops operation. It also closes the on-off valves 31 and 32 to stop the inflow of city water and transitions to wastewater treatment.

The cleaning process will end when a certain amount of time (e.g., 5 minutes) has elapsed since the start of polarity reversal.

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

Next, the operation of the water softener 1 during wastewater treatment will be explained with reference to the "During wastewater treatment" section of Figure 4.

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

Next, the on-off valve 34 is opened, the water pump 20 is operating, and the electrode 13 is not operating. As a result, the raw water remaining in the path from the inside of the water tank 15 to the electrolytic cell 12 via the water supply flow path 36, the alkaline electrolyzed water remaining in the path from the inside of the electrolytic cell 12 to the first drain outlet 16 via the first supply flow path 22a and the first drain flow path 37, and the electrolyzed water remaining in the path from the inside of the electrolytic cell 12 to the second drain outlet 18 via the second supply flow path 24a and the second drain flow path 38 can be discharged outside the device.

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

When the drainage process is completed, the water softening device 1 stops the operation of the water pump 20. Also, the on-off valves 30 and 34 are closed, and the on-off valves 31, 32, and 33 are opened. Furthermore, the water flow direction of the selection valve 17 is set to the direction of the water softening tank 3, and the water flow direction of the selection valve 19 is set to the direction of the neutralization tank 4, thereby transitioning to the water softening process.

The drainage process will end when a certain amount of time (e.g., 1 minute) has elapsed since the drainage process began.

(Water softening treatment)
When the drainage treatment is completed, the water softening device 1 starts water softening treatment.

Next, the operation of the water softening device 1 during water softening will be explained with reference to the "Water softening" section in Figure 4.

As shown in FIG. 4, in the water softening device 1, during the water softening process (softening water), the on-off valve 33 provided at the water intake 5 is opened while the on-off valve 31 and on-off valve 32 are open. In this way, the water softening device 1 allows city water (raw water containing hardness components) from the outside to flow through the water softening tank 3 and the neutralization tank 4, and softened water (neutral soft water) can be taken out from the water intake 5. At this time, the on-off valves 27, 28, 29, 30, and 34 are all closed. In addition, the operation of the electrode 13 of the electrolytic cell 12 and the water pump 20 is 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 7 to the water softening tank 3 by the pressure of city water. The raw water supplied to the water softening tank 3 flows through the weakly acidic cation exchange resin 10 provided in the water softening tank 3. At this time, the cations, which are hardness components in the raw water, are adsorbed by the action of the weakly acidic cation exchange resin 10, and hydrogen ions are released (ion exchange is performed). The raw water is softened by removing the cations from the raw water. The softened water further passes through the flow path 8 and proceeds to the neutralization tank 4. In the neutralization tank 4, the hydrogen ions contained in the softened water are adsorbed by the action of the weakly basic anion exchange resin 11. In other words, the hydrogen ions are removed from the softened water after the treatment, so the lowered pH increases, and the water becomes softened neutral water for domestic use, which can be taken out from the water intake 5 through the flow path 9.

Then, the water softening device 1 executes the regeneration process when the time period specified by the control unit 35 is reached or when the water softening process exceeds a certain period of time.

In this manner, the water softening device 1 repeatedly performs the water softening process, regeneration process, cleaning process, and drainage process.

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

(1) The water softening device 1 includes a water softening tank 3, a neutralization tank 4, an electrolysis tank 12, a water storage tank 15, and a separation section 14. The water softening tank 3 softens raw water containing hardness components using a weakly acidic cation exchange resin 10. The neutralization tank 4 neutralizes the pH of the softened water that has passed through the water softening tank using a weakly basic anion exchange resin 11. The electrolysis tank 12 generates acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 10 in the water softening tank 3, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin 11 in the neutralization tank 4. The water storage tank 15 mixes the acidic electrolyzed water that has passed through the water softening tank 3 and the alkaline electrolyzed water that has passed through the neutralization tank 4, and supplies the resulting mixture to the electrolysis tank 12. The separation section 14 is provided in the flow path that connects the electrolytic cell 12 and the neutralization cell 4, and is designed to separate precipitates caused by hardness components contained in the water introduced into the electrolytic cell 12.

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

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

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

The water softener 1a according to the second embodiment differs from the first embodiment in that an ion concentration detector 39 is provided downstream of the separation section 14. In other words, the water softener 1a according to the second embodiment controls the polarity reversal of the electrolytic cell 12 to end when the ion concentration falls below a reference value, based on information about the ion concentration of the acidic electrolyzed water after polarity reversal that has flowed through the separation section 14. The rest of the configuration of the water softener 1a is the same as that of the water softener 1 according to the first embodiment. Below, the contents already explained in the first embodiment will not be explained again as appropriate, and the differences from the first embodiment will be mainly explained.

As shown in FIG. 5, the water softener 1a is provided with an ion concentration detector 39 on the second supply flow path 24a, downstream of the separator 14 and upstream of the selection valve 19.

The ion concentration detection unit 39 detects the ion concentration of the acidic electrolyzed water that flows through the separation unit 14 during the cleaning process. The ion concentration detection unit 39 is connected to the control unit 35 wirelessly or via a wire so that they can communicate with each other, and information regarding the detected ion concentration is used as an input signal for the control unit 35.

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

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

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

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

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

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

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

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

As shown in FIG. 6, the water softener 1b includes a water tank separator 40 near the outlet of the water tank 15 (the connection between the water tank 15 and the water supply flow path 36). In other words, in the water softener 1b, the separator 14 and the water tank separator 40 separate precipitates caused by hardness components.

As described above, in the water tank 15, the amount of hydroxide ions contained in the alkaline electrolyzed water is small in the early stage of the regeneration process, but since the regeneration of the neutralization tank 4 is completed earlier than the regeneration of the soft water tank 3, the amount of hydroxide ions contained in the alkaline electrolyzed water increases in the latter stage of the regeneration process. In other words, in the latter stage of the regeneration process, the acidic electrolyzed water containing hardness components released from the soft water tank 3 and the alkaline electrolyzed water released from the neutralization tank 4 are mixed, creating a state in which precipitation is likely to occur. As a result, the hardness components (e.g., calcium ions, magnesium ions) released from the soft water tank 3 react with the hydroxide ions from the neutralization tank 4 to become precipitates. Therefore, the water tank separation unit 40 separates the precipitates generated in the water tank 15. As with the separation unit 14, the water tank separation unit 40 may be of any form as long as it can separate precipitates generated by the reaction between the hardness components and the alkaline electrolyzed water. As mentioned above, examples of such filters include cartridge-type filters, filtration layers using granular filter media, cyclone-type solid-liquid separators, and hollow fiber membranes.

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

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

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

(5) The water softener 1b is configured to have a separation section 14 provided downstream of the electrolytic cell 12 with respect to the cleaning flow path 26, and a water tank separation section 40 provided upstream of the electrolytic cell 12. This reduces the hardness components contained in the electrolytic water supplied to the electrolytic cell 12, thereby reducing the amount of precipitates that form in the electrolytic cell 12. This further reduces the frequency of maintenance of the separation section 14, making the water softener 1b usable for a long period of time.

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

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

In addition, in the water softening device 1 according to the first embodiment, in the cleaning process (during cleaning), the raw water is introduced from the inlet 2 through the water softening tank 3, the neutralization tank 4, the second recovery flow path 25, and the water storage tank 15 into the electrolytic tank 12, but this is not limited thereto. For example, the first recovery flow path 23 may be used instead of the second recovery flow path 25. This makes it possible to recover the acidic electrolytic water containing hardness components remaining in the first recovery flow path 23.

In addition, the water softening device 1 according to the first embodiment may be configured so that the water tank 15 further includes an on-off valve and an air vent valve. When the on-off valve provided in the water tank 15 is opened during drainage treatment, the water in the water tank 15 is drained to the outside by the action of the air vent valve. This makes it possible to shorten the time required for drainage treatment.

In addition, in the water softening device 1 according to the first embodiment, the first drain outlet 16 and the second drain outlet 18 are provided as a configuration for discharging the electrolytic water sent from the electrolytic cell 12 to the outside of the device during the cleaning process and the drainage process, but this is not limited to this. For example, it is preferable to mix and discharge the alkaline electrolytic water discharged from the first drain outlet 16 and the acidic electrolytic water discharged from the second drain outlet 18. This allows the acidic electrolytic water and the alkaline electrolytic water to be neutralized and discharged.

In the water softening device 1 according to the first embodiment, the separation section 14 is configured to be cleaned, but this is not limiting. For example, the separation section 14 may not be cleaned. Although the above-mentioned effect (2) cannot be obtained, the effect of simplifying the device configuration, making the device smaller, or reducing the cost of the device can be enjoyed.

The water softening device of the present invention can be applied to a water purification device installed at the point of use (POU: Point of Use) or a water purification device installed at the building entrance (POE: Point of Entry).

LIST OF SYMBOLS 1 Water softener 1a Water softener 1b Water softener 2 Inlet 3 Water softener tank 4 Neutralization tank 5 Water intake 6 Regeneration device 7 Flow path 8 Flow path 9 Flow path 10 Weakly acidic cation exchange resin 11 Weakly basic anion exchange resin 12 Electrolytic cell 13 Electrode 13a Electrode 13b Electrode 14 Separation section 15 Water storage tank 16 First drain outlet 17 Selection valve 18 Second drain outlet 19 Selection valve 20 Water pump 21 Circulation flow path 21a First circulation flow path 21b Second circulation flow path 22 First supply flow path 22a First supply flow path 22b First supply flow path 23 First recovery flow path 24 Second supply flow path 24a Second supply flow path 24b Second supply flow path 25 Second recovery flow path 26 Washing flow path 26a First cleaning flow path 26b Second cleaning flow path 27 On-off valve 28 On-off valve 29 On-off valve 30 On-off valve 31 On-off valve 32 On-off valve 33 On-off valve 34 On-off valve 35 Control unit 36 Water supply flow path 37 First drainage flow path 38 Second drainage flow path 39 Ion concentration detection unit 40 Water tank separation unit

Claims (4)

a water softening tank for softening raw water containing hardness components using a weakly acidic cation exchange resin;
a neutralization tank for neutralizing the pH of the softened water that has passed through the softening tank with a weakly basic anion exchange resin;
an electrolytic cell for producing acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening cell, and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization cell;
a water storage tank for mixing the acidic electrolyzed water that has passed through the softening tank and the alkaline electrolyzed water that has passed through the neutralization tank and supplying the resulting mixture to the electrolysis tank;
a separation section provided in a flow path that communicates between the electrolytic cell and the neutralization cell, the separation section separating precipitates resulting from the hardness components contained in the water introduced into the electrolytic cell;
A water softening device comprising: A control unit for controlling the regeneration treatment of the weakly acidic cation exchange resin in the water softening tank and the weakly basic anion exchange resin in the neutralization tank is further provided.
2. The water softening apparatus according to claim 1, wherein the control unit controls the polarity inversion of the electrolytic cell after the completion of the regeneration process, and controls the acidic electrolyzed water after the polarity inversion to flow through the separation unit and to be discharged outside the apparatus. The water softening device according to claim 2, characterized in that the control unit controls the polarity reversal of the electrolytic cell to end when the ion concentration determined based on information about the ion concentration of the acidic electrolytic water after polarity reversal that has flowed through the separation unit becomes less than a reference value. The water softening device according to any one of claims 1 to 3, characterized in that the water tank further comprises a water tank separation section that separates precipitates resulting from the hardness components contained in the water introduced into the tank.

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