JP2024090113A - Water softening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water softening device capable of suppressing an increase in hardness of softening water after water softening treatment even when a raw water temperature is low.

SOLUTION: A water softening device 1 includes a water softening tank 3 in which raw water containing hardness components is softened with a weakly acidic cation exchange resin 33, a neutralization tank 4 in which the pH of the softened water that has passed through the water softening tank 3 is neutralized with a weakly basic anion exchange resin 34, a temperature detection part 61 that detects the temperature of the raw water flowing into the water softening tank 3, and a performance securing part 62 that operates to secure the ion exchange capacity of the weakly acidic cation exchange resin 33 based on the detection results of the temperature detection part 61. The performance securing part 62 adjusts at least one of the flow rate or temperature of the raw water flowing into the water softening tank 3 when the temperature of the raw water detected by the temperature detection part 61 is below a predetermined temperature.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a water softening device.

In conventional water softening devices, weakly acidic cation exchange resins have hydrogen ions at the ends of their functional groups, and the raw water is softened by exchanging hardness components (e.g., calcium ions, magnesium ions) in the raw water for hydrogen ions. A method of regenerating cation exchange resins without using salt is known in which the cation exchange resins are regenerated using acidic electrolyzed water produced by electrolysis (see, for example, Patent Document 1).

Water softened by weakly acidic cation exchange resin becomes acidic because hydrogen ions are released in place of hardness components. To neutralize this, weakly acidic cation exchange resins are sometimes used in combination with weakly basic anion exchange resins. A method of using alkaline electrolyzed water produced by electrolysis is known as a method of regenerating weakly basic anion exchange resins (see, for example, Patent Document 2).

JP 2011-30973 A JP 2010-142674 A

In such conventional water softening devices, as the temperature of the inflowing raw water drops, the ion exchange capacity of the weakly acidic cation exchange resin and the weakly basic anion exchange resin decreases, causing the hardness of the discharged soft water to increase, meaning that the softening performance decreases.

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 even when the raw water temperature is low.

To achieve this objective, the water softening device of the present invention comprises a softening tank that softens raw water containing hardness components with a weakly acidic cation exchange resin to produce acidic soft water, a neutralization tank that neutralizes the pH of the acidic soft water that has passed through the softening tank with a weakly basic anion exchange resin, a temperature detection unit that detects the temperature of the raw water flowing into the softening tank, and a performance assurance unit that operates to ensure the ion exchange capacity of the weakly acidic cation exchange resin based on the detection result of the temperature detection unit, and the performance assurance unit adjusts at least one of the flow rate or temperature of the raw water flowing into the softening tank when the temperature detected by the temperature detection unit is below a predetermined temperature. This achieves the intended objective.

The present invention provides a water softening device that can suppress a decrease in water softening performance even when the raw water temperature is low.

FIG. 1 is a conceptual diagram showing the configuration of a water softening device according to the first embodiment. FIG. 2 is a configuration diagram showing a water-softening flow path of the water-softening device according to the first embodiment. FIG. 3 is a configuration diagram showing the soft water tank regeneration/circulation flow path and the neutralization tank regeneration/circulation flow path of the water softening device according to the first embodiment. FIG. 4 is a configuration diagram showing the regeneration flow path cleaning flow path of the water softening device according to the first embodiment. FIG. 5 is a configuration diagram showing an electrolytic cell cleaning flow path of the water softening device according to the first embodiment. FIG. 6 is a configuration diagram showing a trap tank cleaning flow path of the water softening device according to the first embodiment. FIG. 7 is a diagram showing a control method of the water softening device according to the first embodiment. FIG. 8 is a functional block diagram of the water softening device according to the first embodiment. FIG. 9 is a conceptual diagram showing the configuration of a water softening device according to embodiment 1a. FIG. 7 is a diagram showing a method for controlling the water softening device according to embodiment 1a.

The following describes an embodiment of the present invention with reference to the drawings. Note that the following embodiment is merely 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 ratios of sizes and thicknesses of 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 softening device 1 is a device that produces neutral soft water from raw water that contains hardness components and is supplied from the outside. The raw water is water (water to be treated) that is introduced into the device from an inlet 2, and is, for example, city water or well water. The raw water contains hardness components (for example, calcium ions or magnesium ions). By performing a water softening process using the water softening device 1, neutral soft water with reduced hardness is obtained, and soft water can be used even in areas where the raw water has high hardness.

Specifically, as shown in FIG. 1, the water softening device 1 includes an inlet 2, a temperature detection unit 61, a performance assurance unit 62, a water softening tank 3 (first water softening tank 3a and second water softening tank 3b), a neutralization tank 4 (first water softening tank 4a and second water softening tank 4b), a water intake 7, a regeneration device 8, and a control unit 15.

The water softener 1 also includes a drain port 13, multiple on-off valves (on-off valves 18 to 23), multiple flow path switching valves (flow path switching valves 24 to 27), and multiple flow paths (flow paths 28 to 32, flow path 53, first supply flow path 35, second supply flow path 36, first recovery flow path 37, second recovery flow path 38, neutralization tank bypass flow path 42, soft water tank bypass flow path 44, and drain flow path 54), the details of which will be described later. Note that the multiple flow paths (flow paths 28 to 32, flow path 53, first supply flow path 35, second supply flow path 36, first recovery flow path 37, second recovery flow path 38, neutralization tank bypass flow path 42, soft water tank bypass flow path 44, and drain flow path 54) are, for example, pipes or other tubes.

(Inlet and intake)
The inlet 2 is connected to a source of raw water and is an opening through which the raw water is introduced into the water softening device 1 .

The water intake 7 is an opening that flows through the water softening apparatus 1 and supplies the softened water to the outside of the apparatus. The water softening apparatus 1 can take out the softened water from the water intake 7 by the pressure of the raw water flowing in from the inlet 2.

In the water softening device 1, in the softening process where the water is softened, raw water supplied from the outside flows through the inlet 2, the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the flow path 29, the first neutralization tank 4a, the flow path 30, the second soft water tank 3b, the flow path 31, the second neutralization tank 4b, the flow path 32, and the water intake 7 in that order, and is discharged as neutral soft water.

(Soft water tank)
The water softener tank 3 softens raw water containing hardness components by the action of the weakly acidic cation exchange resin 33 filled inside. Specifically, the water softener 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. The water softener tank 3 is equipped with the weakly acidic cation exchange resin 33 that has hydrogen ions at the ends of its functional groups.

The soft water tank 3 is, for example, a cylindrical container filled with weakly acidic cation exchange resin 33. The soft water tank 3 includes a first soft water tank 3a and a second soft water tank 3b.

The first soft water tank 3a is filled with a first weakly acidic cation exchange resin 33a. The first soft water tank 3a softens the raw water that flows in from the inlet 2. The first soft water tank 3a is equipped with a flow path switching valve 24. Details of the flow path switching valve will be described later.

The second soft water tank 3b is filled with a second weakly acidic cation exchange resin 33b. The second soft water tank 3b softens the water that has passed through the first neutralization tank 4a (described later). The second soft water tank 3b is equipped with a flow path switching valve 26.

In the following, the first weakly acidic cation exchange resin 33a and the second weakly acidic cation exchange resin 33b will be described as weakly acidic cation exchange resin 33 when there is no particular need to distinguish between them.

The weakly acidic cation exchange resin 33 is an ion exchange resin that has hydrogen ions at the ends of its functional groups. The weakly acidic cation exchange resin 33 adsorbs cations (calcium ions, magnesium ions) that are hardness components contained in the raw water passed through it, and releases hydrogen ions. The soft water treated with the weakly acidic cation exchange resin 33 contains many hydrogen ions that have been exchanged with hardness components. In other words, the soft water flowing out of the first soft water tank 3a and the second soft water tank 3b is soft water (acidic soft water) that contains many hydrogen ions and is acidified.

Since the terminal functional group of the weakly acidic cation exchange resin 33 is a hydrogen ion, the weakly acidic cation exchange resin 33 can be regenerated using acidic electrolyzed water in the regeneration process described below. At this time, the weakly acidic cation exchange resin 33 releases cations, which are hardness components that were captured during the water softening process.

There are no particular limitations on the weakly acidic cation exchange resin 33, and any general-purpose resin can be used, such as one that uses a carboxyl group (-COOH) as the exchange group. Alternatively, the weakly acidic cation exchange resin 33 may be a resin in which the hydrogen ion (H+), which is the counter ion of the carboxyl group, is replaced by a cation such as a metal ion or ammonium ion (NH4+).

(Neutralization tank)
The neutralization tank 4 neutralizes the pH of the soft water (acidified soft water) containing hydrogen ions that comes out of the soft water tank 3 by the action of the weakly basic anion exchange resin 34, to make the soft water neutral. Specifically, the neutralization tank 4 adsorbs the hydrogen ions contained in the soft water flowing in from the soft water tank 3 together with the anions, thereby increasing the pH of the soft water, and making it possible to make the soft water neutral.

The neutralization tank 4 is equipped with a weakly basic anion exchange resin 34.

The neutralization tank is, for example, a cylindrical container filled with a weakly basic anion exchange resin 34. The neutralization tank 4 is composed of a first neutralization tank 4a and a second neutralization tank 4b.

The first neutralization tank 4a is filled with a first weakly basic anion exchange resin 34a. The first neutralization tank 4a neutralizes the acidic soft water that has flowed through the first soft water tank 3a. The first neutralization tank 4a is equipped with a flow path switching valve 25.

The second neutralization tank 4b is filled with a second weakly basic anion exchange resin 34b. The second neutralization tank 4b neutralizes the acidic soft water that has flowed through the second soft water tank 3b. The second neutralization tank 4b is equipped with a flow path switching valve 27.

In the following, the first weakly basic anion exchange resin 34a and the second weakly basic anion exchange resin 34b will be described as weakly basic anion exchange resin 34 when there is no particular need to distinguish between them.

The weakly basic anion exchange resin 34 neutralizes the hydrogen ions contained in the water passing through it, producing neutral water. The weakly basic anion exchange resin 34 is regenerated using alkaline electrolyzed water in the regeneration process described below.

There are no particular limitations on the weakly basic anion exchange resin 34, and any general-purpose resin can be used, such as a free base type anion exchange resin.

(Temperature detection section)
The temperature detection unit 61 is a device that detects the temperature of the raw water flowing into the first soft water tank 3a. The temperature detection unit 61 is connected to the control unit 15 (described later) wirelessly or via wire so as to be able to communicate with the control unit 15, and is capable of transmitting the detected raw water temperature information to the control unit 15. There are no particular limitations on the temperature detection unit 61, and a general-purpose device can be used, such as a resistance temperature sensor.

(Performance Assurance Department)
The performance assurance unit 62 is a part that operates based on instructions from the control unit 15 and suppresses deterioration of the water softening performance.

The performance assurance unit 62 includes a flow rate adjustment unit 63 that adjusts the flow rate of raw water flowing into the first soft water tank 3a. The performance assurance unit 62 is connected to the control unit 15 (described later) via wireless or wired communication, and the operation of the performance assurance unit 62 is controlled by the control unit 15. When the performance assurance unit 62 is activated by the control unit 15, the performance assurance unit 62 activates the flow rate adjustment unit 63, and the flow rate adjustment unit 63 reduces the flow rate of raw water flowing into the first soft water tank 3a to a predetermined flow rate.

The predetermined flow rate is, for example, half the maximum flow rate that can flow into the water softener 1 during softening operation (if the maximum flow rate of the water softener 1 is 20 L/min, the predetermined flow rate is 10 L/min), and is determined by the softening performance during softening operation. The softening performance is affected by the contact time between the weakly acidic cation exchange resin 33 provided in the softening tank 3 and the raw water. In general, when the ion reaction rate is constant, the longer the contact time between the weakly acidic cation exchange resin 33 and the raw water, i.e., the longer the time during which the ion exchange reaction can occur, the better the softening performance. Therefore, by reducing the flow rate of the raw water flowing into the first softening tank 3a to a predetermined flow rate by the flow rate adjustment unit 63, the hardness of the softened water discharged from the first softening tank 3a can be reduced. The maximum flow rate that can flow into the water softener 1 may be, for example, the maximum flow rate of the raw water flowing into the water softener 1, or the maximum flow rate of the softened water flowing out of the device from the water intake 7. In the first embodiment, since no water flows out from any other than the water intake 7 during the water softening operation, the amount of raw water flowing into the water softening device 1 can be considered to be the same as the amount of raw water flowing out.

There are no particular limitations on the flow rate adjustment unit 63, and any general-purpose device can be used, such as a flow rate adjustment valve.

(Playback device)
The regeneration device 8 is an apparatus that regenerates the weakly acidic cation exchange resin 33 in the soft water tank 3 (first soft water tank 3a and second soft water tank 3b) and regenerates the weakly basic anion exchange resin 34 in the neutralization tank 4 (first neutralization tank 4a and second neutralization tank 4b).

Specifically, the regeneration device 8 includes an electrolytic cell 9, a capture unit 10, a first water pump 11, and a second water pump 12. In the regeneration device 8, the second supply flow path 36, the first recovery flow path 37, and the second recovery flow path 38 are connected to the second soft water tank 3b, the second neutralization tank 4b, the flow path 28, and the flow path 29 via the first supply flow path 35 and the capture unit 10, respectively. Details of each flow path will be described later. The first supply flow path 35, the second supply flow path 36, the first recovery flow path 37, the second recovery flow path 38, the neutralization tank bypass flow path 42, and the soft water tank bypass flow path 44 form the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40, which will be described later.

((Electrolytic cell))
The electrolytic cell 9 generates and discharges acidic electrolyzed water and alkaline electrolyzed water by electrolyzing the water (water supplied from the inlet 2) using a pair of electrodes 41 (electrodes 41a and 41b) provided inside. More specifically, hydrogen ions are generated by electrolysis at the electrode 41a, which serves as an anode during electrolysis in the regeneration process, and acidic electrolyzed water is generated. Meanwhile, hydroxide ions are generated by electrolysis at the electrode 41b, which serves as a cathode during electrolysis in the regeneration process, and alkaline electrolyzed water is generated. The electrolytic cell 9 supplies acidic electrolyzed water to the first soft water tank 3a and the second soft water tank 3b via the first supply flow path 35 and the neutralization tank bypass flow path 42, and supplies alkaline electrolyzed water to the first neutralization tank 4a and the second neutralization tank 4b via the second supply flow path 36 and the soft water tank bypass flow path 44. Although details will be described later, the acidic electrolyzed water generated by the electrolytic cell 9 is used to regenerate the weakly acidic cation exchange resin 33 in the first soft water tank 3a and the second soft water tank 3b, and the alkaline electrolyzed water generated by the electrolytic cell 9 is used to regenerate the weakly basic anion exchange resin 34 in the first neutralization tank 4a and the second neutralization tank 4b. The electrolytic cell 9 is configured so that the current supply state to the pair of electrodes 41 can be controlled by the control unit 15, which will be described later.

(Water Pump)
The first water pump 11 is a device that circulates acidic electrolyzed water through the soft water tank regeneration circulation flow path 39 (see FIG. 3) during regeneration treatment by the regeneration device 8. The first water pump 11 is provided in the first recovery flow path 37 that communicates between the first soft water tank 3a and the electrolytic tank 9. The reason for this arrangement is that the first water pump 11 alone can easily circulate acidic electrolyzed water through the soft water tank regeneration circulation flow path 39.

The second water supply pump 12 is a device for circulating alkaline electrolyzed water through the neutralization tank regeneration circulation flow path 40 (see FIG. 3). The second water supply pump 12 is provided in the second recovery flow path 38 that communicates between the first neutralization tank 4a and the electrolytic tank 9. The reason for this arrangement is that the alkaline electrolyzed water can be easily circulated through the neutralization tank regeneration circulation flow path 40 by the second water supply pump 12 alone.

The first water pump 11 and the second water pump 12 are also connected to the control unit 15 (described later) via wires or wirelessly so that they can communicate with each other.

((Capture section))
The capture section 10 is provided in a second supply flow passage 36 that communicates with the electrolytic bath 9 and the second neutralization bath 4b.

The capture unit 10 captures precipitates contained in the alkaline electrolyzed water sent from the electrolytic cell 9. The precipitates are reaction products generated in the electrolytic cell 9 by the reaction of the hardness components, which are cations released from the first soft water tank 3a and the second soft water tank 3b during the regeneration process, with the alkaline electrolyzed water. More specifically, while the electrolysis of water is being performed in the electrolytic cell 9, the hardness components (e.g., calcium ions, magnesium ions) released from the first soft water tank 3a and the second soft water tank 3b during the regeneration process move to the cathode (electrode 41b). 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 produced or a reaction occurs in which calcium hydroxide is produced when the hardness components are mixed with the alkaline electrolyzed water. The precipitates derived from the hardness components are captured as precipitates by the capture unit 10 provided in the second supply flow path 36. By capturing the precipitates derived from hardness components in the capture section 10, it is possible to prevent the precipitates from flowing into and accumulating in the second neutralization tank 4b. Therefore, when the water softening process is resumed after the regeneration process is completed, it is possible to prevent an increase in the hardness of the soft water discharged from the second neutralization tank 4b, which is caused by the precipitates accumulated in the second neutralization tank 4b reacting with the hydrogen ions released from the first soft water tank 3a and the second soft water tank 3b and ionizing them.

During the regeneration process, the alkaline electrolyzed water from which the precipitates derived from hardness components have passed through the capture unit 10 flows through the second neutralization tank 4b and the first neutralization tank 4a, and is then electrolyzed again in the electrolytic tank 9 to be converted back into alkaline electrolyzed water and used to regenerate the weakly basic anion exchange resin 34. At this time, the acidic electrolyzed water contains fewer hardness components than when the capture unit 10 is not provided. In other words, by capturing the precipitates in the capture unit 10, the hardness of the acidic electrolyzed water is reduced, and the hardness components flowing into the first soft water tank 3a and the second soft water tank 3b can be reduced, and the decrease in the regeneration efficiency of the weakly acidic cation exchange resin 33 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 capture unit 10 may take any form as long as it can separate the precipitates resulting from the reaction between the hardness components and the alkaline electrolyzed water. 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 capture unit 10 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.

The capture section 10 is equipped with an on-off valve 22 and a capture section drain outlet 14.

The on-off valve 22 is a valve provided at the bottom of the capture unit 10 and controls the drainage within the capture unit 10. By opening the on-off valve 22, the water within the capture unit 10 can be drained outside the device through the capture unit drain outlet 14.

The capture section drain outlet 14 is an opening that drains the water in the capture section 10 to the outside of the device. By opening the on-off valve 22 provided upstream of the capture section drain outlet 14, the water in the capture section 10 can be drained to the outside of the device through the capture section drain outlet 14.

((On-off valves, flow path switching valves, and switching valves))
A plurality of on-off valves (on-off valves 18 to 23) are provided in each flow path, respectively, and switch each flow path between an "open" state and a "closed" state.

Multiple on-off valves (on-off valve 18, on-off valve 19, on-off valve 21, and on-off valve 23) start or stop the flow of water to each flow path by opening and closing the valve.

On-off valve 20 and on-off valve 22 are opened during the regeneration flow path cleaning process, electrolytic cell cleaning process, and capture section cleaning process described below, and the regenerated circulating water is discharged outside the device.

A plurality of flow path switching valves (flow path switching valves 24 to 27) are provided in the first soft water tank 3a, the second soft water tank 3b, the first neutralization tank 4a, and the second neutralization tank 4b, respectively. Each of the plurality of flow path switching valves has three openings, the first opening being an inlet and outlet through which water can flow in and out, the second opening being an inlet that does not function as an outlet but functions as an inlet, and the third opening being an outlet that does not function as an inlet but functions as an outlet. Each of the plurality of flow path switching valves is always "open", and when either the inlet or outlet is "open" depending on the water flow direction, the other inlet or outlet is "closed". By providing the flow path switching valves 24 to 27, the number of opening and closing valves required for each flow path in the water softening device 1 can be reduced, and the cost of the water softening device 1 can be reduced.

In addition, the multiple on-off valves (on-off valve 18 to on-off valve 23) and the multiple flow path switching valves (flow path switching valve 24 to flow path switching valve 27) are each connected to the control unit 15 described below so as to be able to communicate with each other wirelessly or via wires.

((Drain))
The drain outlet 13 is an opening provided at the end of the drain flow path 54, and is an opening for discharging water from the apparatus to the outside in the regeneration path cleaning process and the electrolytic cell cleaning process. An opening/closing valve 20 is provided upstream of the drain outlet 13, and water can be discharged from the drain outlet 13 by opening the opening/closing valve 20.

((Control Unit))
The control unit 15 will be described with reference to Fig. 8. Fig. 8 is a functional block diagram of the water softening device according to the first embodiment.

The control unit 15 controls the execution of each process, including the water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process, as well as switching between each process.

Specifically, the control unit 15 controls the switching from the water softening process to the regeneration process, the switching from the regeneration process to the regeneration flow path cleaning process, the switching from the regeneration flow path cleaning process to the electrolytic cell cleaning process, the switching from the electrolytic cell cleaning process to the capture unit cleaning process, and the switching from the capture unit cleaning process to the water softening process.

The control unit 15 also controls the on-off valves 20 and 22 to control the drainage during the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process.

The control unit 15 also controls the flow path switching valves 24 to 27, the on-off valve 18, the on-off valve 19, the on-off valve 21, and the on-off valve 23 to switch the flow paths.

The control unit 15 includes a temperature comparison unit 64 and an operation restriction unit 65.

The temperature comparison unit 64 compares the temperature information sent from the temperature detection unit 61 to the control unit 15 with predetermined temperature information.

The specified temperature is, for example, 20°C. When softening operation is performed, the hardness of the soft water discharged under the reference temperature conditions is compared with the hardness of the soft water discharged under certain temperature conditions, and the temperature conditions are determined such that the hardness of the soft water discharged under certain temperature conditions is 0% to less than +10% of the hardness of the soft water discharged under the reference temperature.

The reference temperature conditions are the most common temperature conditions when the water softener 1 is in use, for example, 25°C. The water softening performance is affected by the ion exchange reaction rate of the weakly acidic cation exchange resin 33 in the water softener tank 3. In general, the reaction rate is affected by temperature, and under high temperature conditions, the reaction rate is faster because the number of ions with energy equal to or greater than the activation energy increases. On the other hand, under low temperature conditions, the reaction rate is slow. If the reaction rate is slow, the water softening performance in the water softener tank 3 will decrease. Therefore, when the temperature falls below a predetermined level, the performance assurance unit 62 is activated, the flow rate adjustment unit 63 is controlled, and the water softening performance is guaranteed, thereby suppressing an increase in the hardness of the soft water discharged even under low raw water temperature conditions.

The operation restriction unit 65 controls the operation of the performance assurance unit 62 based on the temperature information compared by the temperature comparison unit 64. If the temperature information detected by the temperature detection unit 61 is equal to or higher than a predetermined temperature, the operation restriction unit 65 does not activate the performance assurance unit 62. On the other hand, if the temperature information detected by the temperature detection unit 61 is lower than the predetermined temperature, the operation restriction unit 65 activates the performance assurance unit 62.

The control unit 15 has a computer system having a processor and a memory. The processor executes a program stored in the memory, causing the computer system to function as the control unit. Here, the program executed by the processor is pre-recorded in the memory of the computer system, but it may be provided by recording it on a non-transitory recording medium such as a memory card, or it may be provided via a telecommunications line such as the Internet.

(Each flow path)
(Flow path)
The flow path 53 is a flow path that communicates between the inlet 2 and the water intake 7, and is provided with an on-off valve 18. The flow path 53 allows a user of the water softening device 1 to obtain raw water from the water intake 7 even when any one of the regeneration process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process is being performed.

(Water softening flow path)
2, a description will be given of a water softening flow path 43 formed during the water softening process of the water softening device 1. FIG. 2 is a configuration diagram showing the water softening flow path 43 of the water softening device 1.

The soft water passage 43 (diagonal arrow in Figure 2) is a passage that softens the raw water. The raw water that flows through the soft water passage 43 becomes neutral soft water and is discharged outside the device from the water intake 7.

The water softening flow path 43 is formed by the inlet 2, the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the flow path 29, the first neutralization tank 4a, the flow path 30, the second soft water tank 3b, the flow path 31, the second neutralization tank 4b, the flow path 32, and the water intake 7.

The flow path 28 is a flow path that connects the performance assurance unit 62 to the first soft water tank 3a. In other words, the flow path 28 is a flow path that guides raw water containing hardness components from the performance assurance unit 62 to the first soft water tank 3a.

The flow path 29 is a flow path that connects the first soft water tank 3a to the first neutralization tank 4a. In other words, the flow path 29 is a flow path that guides the water softened in the first soft water tank 3a to the first neutralization tank 4a.

The flow path 30 is a flow path that connects the first neutralization tank 4a to the second soft water tank 3b. In other words, the flow path 30 is a flow path that guides the water neutralized in the first neutralization tank 4a to the second soft water tank 3b.

The flow path 31 is a flow path that connects the second soft water tank 3b to the second neutralization tank 4b. In other words, the flow path 31 is a flow path that guides the water softened in the second soft water tank 3b to the second neutralization tank 4b.

The flow path 32 is a flow path that connects the second neutralization tank 4b to the water intake 7. In other words, the flow path 32 is a flow path that guides the softened raw water from the second neutralization tank 4b to the water intake 7.

2, an on-off valve 19 is installed on the flow path 28 downstream of the performance assurance section 62 and upstream of the first soft water tank 3a. An on-off valve 18 is installed in the flow path 53 described later. The first soft water tank 3a and the inlet 2 are connected in communication by closing the on-off valve 18 and opening the on-off valve 19. The flow path switching valve 24 is switched so that the first soft water tank 3a and the first neutralization tank 4a are connected in communication, the flow path switching valve 25 is switched so that the second soft water tank 3b and the second neutralization tank 4b are connected in communication, the flow path switching valve 26 is switched so that the first neutralization tank 4a and the second soft water tank 3b are connected in communication, and the flow path switching valve 27 is switched so that the second soft water tank 3b and the second neutralization tank 4b are connected in communication. This forms a water softening flow path 43 that connects the inlet 2 to the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the flow path 29, the first neutralization tank 4a, the flow path 30, the second soft water tank 3b, the flow path 31, the second neutralization tank 4b, the flow path 32, and the water intake 7. At this time, the on-off valves 20, 21, and 23 are closed.

(Regenerative circulation flow path)
Next, a description will be given of a soft water tank regeneration circulation flow path 39 and a neutralization tank regeneration circulation flow path 40 formed during the regeneration process of the water softening device 1 with reference to Fig. 3. Fig. 3 is a configuration diagram showing the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 of the water softening device 1.

First, we will explain the soft water tank regeneration circulation flow path 39.

The soft water tank regeneration circulation flow path 39 is a flow path through which acidic electrolyzed water flows during the regeneration process to regenerate the first soft water tank 3a and the second soft water tank 3b. As shown in FIG. 3 (white arrow), this is the flow path through which water pumped by the first water supply pump 11 flows through the electrolytic tank 9, the second soft water tank 3b, and the first soft water tank 3a, and circulates back to the electrolytic tank 9.

Specifically, the soft water tank regeneration circulation flow path 39 is composed of the first supply flow path 35 connecting the electrolytic tank 9, the second soft water tank 3b, the first soft water tank 3a, and the first water supply pump 11, the neutralization tank bypass flow path 42, and the first recovery flow path 37.

The first supply flow path 35 is a flow path that connects the downstream side of the electrolytic cell 9 to the downstream side of the second soft water tank 3b, and is a flow path that supplies acidic electrolyzed water from the electrolytic cell 9 to the second soft water tank 3b.

The neutralization tank bypass flow path 42 is a flow path that bypasses the first neutralization tank 4a and connects the upstream side of the second soft water tank 3b to the downstream side of the first soft water tank 3a, and is a flow path that supplies acidic electrolyzed water from the second soft water tank 3b to the first soft water tank 3a.

The first recovery flow path 37 is a flow path that connects the upstream side of the first soft water tank 3a to the electrolytic cell 9, and is a flow path that recovers the acidic electrolytic water containing hardness components that has passed through the first soft water tank 3a and the second soft water tank 3b to the electrolytic cell 9. A first water pump 11 is provided in the first recovery flow path 37.

The soft water tank regeneration circulation flow path 39 is a flow path that introduces the acidic electrolyzed water discharged from the electrolytic tank 9 into the first soft water tank 3a and the second soft water tank 3b from the downstream side of the first soft water tank 3a and the second soft water tank 3b, and causes it to flow out from the upstream side, where a greater amount of hardness components are adsorbed than on the downstream side of the soft water tank. Note that the downstream side refers to the downstream side of the flow path during the water softening process.

Next, we will explain the neutralization tank regeneration circulation flow path 40.

The neutralization tank regeneration circulation flow path 40 is a flow path through which alkaline electrolyzed water flows during the regeneration process to regenerate the first neutralization tank 4a and the second neutralization tank 4b. As shown in FIG. 3 (black arrow), this is the flow path through which water pumped by the second water supply pump 12 flows through the electrolytic tank 9, the second neutralization tank 4b, and the first neutralization tank 4a, and circulates back to the electrolytic tank 9.

Specifically, the neutralization tank regeneration circulation flow path 40 is composed of the electrolytic tank 9, the second neutralization tank 4b, the first neutralization tank 4a, the second supply flow path 36 connecting the second water supply pump 12, the soft water tank bypass flow path 44, and the second recovery flow path 38.

The second supply flow path 36 is a flow path that connects the downstream side of the electrolytic cell 9 to the downstream side of the second neutralization cell 4b, and is a flow path that supplies alkaline electrolyzed water from the electrolytic cell 9 to the second neutralization cell 4b. The second supply flow path 36 is provided with a capture unit 10, an on-off valve 21, and an on-off valve 23.

The soft water tank bypass flow path 44 is a flow path that bypasses the second soft water tank 3b and connects the upstream side of the second neutralization tank 4b to the downstream side of the first neutralization tank 4a, and is a flow path that supplies alkaline electrolyzed water from the second neutralization tank 4b to the first neutralization tank 4a.

The second recovery flow path 38 is a flow path that connects the upstream side of the first neutralization tank 4a to the electrolytic tank 9, and is a flow path that recovers the alkaline electrolytic water that has passed through the first neutralization tank 4a and the second neutralization tank 4b to the electrolytic tank 9. A second water pump 12 is provided in the second recovery flow path 38.

((Regeneration flow path cleaning flow path))
Next, a regeneration flow passage cleaning flow passage 45 formed during the regeneration flow passage cleaning step of the water softening device 1 will be described with reference to Fig. 4. Fig. 4 is a configuration diagram showing the regeneration flow passage cleaning flow passage 45 of the water softening device 1.

The regeneration flow path cleaning flow path 45 is a flow path that discharges the high hardness water remaining in the flow path outside the device during the regeneration flow path cleaning process described below, without allowing it to flow into the first neutralization tank 4a and the second neutralization tank 4b. The regeneration flow path cleaning flow path 45 is composed of a first drainage flow path 46 and a second drainage flow path 47.

As shown in FIG. 4 (white arrow), the first drainage flow path 46 is composed of flow paths that connect the inlet 2 to the first water pump 11, the electrolytic cell 9, the on-off valve 20, and the drainage port 13. Specifically, the first drainage flow path 46 passes raw water flowing in from the inlet 2 through the temperature detection unit 61, the performance assurance unit 6
2, the flow path 28, the first recovery flow path 37, the first water supply pump 11, the electrolytic cell 9, the drainage flow path 54, the on-off valve 20, and the drain outlet 13 in this order.

The drainage flow path 54 is a flow path that is connected at one end to the first supply flow path 35 and at the other end to the drain outlet 13. An on-off valve 20 is provided in the drainage flow path 54, and by opening the on-off valve 20, water in the flow path can be drained outside the device, and by closing the on-off valve 20, drainage from the drain outlet 13 can be stopped.

As shown in FIG. 4 (black arrow), the second drainage flow path 47 is composed of flow paths that connect the inlet 2 to the first soft water tank 3a, the second soft water tank 3b, the on-off valve 20, and the drain outlet 13. Specifically, the second drainage flow path 47 is a flow path that circulates the raw water that flows in from the inlet 2 through the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the neutralization tank bypass flow path 42, the second soft water tank 3b, the first supply flow path 35, the on-off valve 20, and the drain outlet 13 in that order.

The flow rate of water flowing through the second drainage flow path 47 is preferably controlled to be greater than the flow rate of water flowing through the first drainage flow path. This allows the high hardness water in the second drainage flow path, which is a flow path including a soft water tank used during the water softening process, to be preferentially replaced with raw water. Therefore, the influence of high hardness water when the water softening process is started can be suppressed.

((Electrolytic bath cleaning flow path))
Next, an electrolytic cell cleaning flow path 49 formed during the electrolytic cell cleaning step of the water softening device 1 will be described with reference to Fig. 5. Fig. 5 is a configuration diagram showing the electrolytic cell cleaning flow path 49 of the water softening device 1.

The electrolytic bath cleaning flow path 49 is a flow path that removes deposits caused by hardness components in the electrolytic bath 9 and the neutralization bath regeneration circulation flow path 40 during the electrolytic bath cleaning process described below. The electrolytic bath cleaning flow path 49 is composed of a first drainage flow path 46 and a third drainage flow path 50.

As shown in FIG. 5 (black arrow), the third drainage flow path 50 is composed of each flow path that connects the inlet 2 to the first soft water tank 3a, the second water pump 12, the electrolytic cell 9, the on-off valve 21, the capture unit 10, the on-off valve 22, and the capture unit drain outlet 14. Specifically, the third drainage flow path 50 is a flow path that circulates the raw water flowing in from the inlet 2 through the temperature detection unit 61, the performance guarantee unit 62, the flow path 28, the first soft water tank 3a, the second recovery flow path 38, the second water pump 12, the electrolytic cell 9, the second supply flow path 36, the on-off valve 21, the capture unit 10, and the on-off valve 22 in that order, and discharges it from the capture unit drain outlet 14 to the outside of the device. More specifically, in the third drainage flow path 50, the raw water flowing in from the inlet 2 is flowed into the first soft water tank 3a via the temperature detection unit 61, the performance guarantee unit 62, and the flow path 28, and is made into acidic soft water. The generated acidic soft water is allowed to flow through the second recovery flow path 38 and the second water pump 12 into the electrolytic cell 9. The acidic soft water is then allowed to flow through the second supply flow path 36, in the order of the on-off valve 21, the capture unit 10, and the on-off valve 22, dissolving the precipitate in the capture unit 10 and discharging it from the capture unit drain outlet 14 to the outside of the device.

((Capture part cleaning flow path))
Next, a capture part cleaning flow path 51 formed during the capture part cleaning process of the water softening device 1 will be described with reference to Fig. 6. Fig. 6 is a configuration diagram showing the capture part cleaning flow path 51 of the water softening device 1.

The capture part cleaning flow path 51 is a flow path that removes precipitates derived from hardness components that have precipitated in the capture part 10 during the capture part cleaning process described below. The capture part cleaning flow path 51 is configured to include a fourth drainage flow path 52.

As shown in FIG. 6, the capture unit cleaning flow path 51 is composed of flow paths that connect the inlet 2 to the first soft water tank 3a, the first neutralization tank 4a, the second soft water tank 3b, the second neutralization tank 4b, the capture unit 10, and the capture unit drain 14. Specifically, the capture unit cleaning flow path 51 is a flow path that circulates the raw water flowing in from the inlet 2 through the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the flow path 29, the first neutralization tank 4a, the flow path 30, the second soft water tank 3b, the flow path 31, the second neutralization tank 4b, the second supply flow path 36, the opening/closing valve 23, the capture unit 10, and the opening/closing valve 22 in that order, and then discharges the raw water from the capture unit drain to the outside of the device.

The above is the configuration of the water softening device 1.

Next, we will explain the operation of the water softener 1.

(Water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process)
Next, the water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process of the water softening device 1 will be described with reference to Fig. 7. Fig. 7 is a diagram showing the state during operation of the water softening device 1. Note that, hereinafter, a series of steps including the water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process may be referred to as a softening regeneration process.

In the water softening process, regeneration process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture section cleaning process, the control unit 15 controls the on-off valves 18 to 23, the flow path switching valves 24 to 27, the first water supply pump 11, and the second water supply pump 12 to switch to the respective flow states, as shown in FIG. 7.

In Figure 7, "ON" indicates that the corresponding on-off valve is "open" and that the corresponding water pump is operating. A blank space indicates that the corresponding on-off valve is "closed" and that the corresponding water pump is stopped.

In addition, "from (component number) to (component number)" in FIG. 7 indicates that the corresponding flow path switching valve is connected to a flow path in the direction in which water is sent from the corresponding component to the corresponding component. For example, flow path switching valve 24 in the water softening process connects each flow path so that water can be sent from flow path 28 to flow path 29.

In addition, "to (element number)" in Figure 7 indicates a state in which the corresponding flow path switching valve is connected to a flow path in a direction in which water may be sent to the corresponding element. In this case, although the flow path is connected, the environment is such that water is unlikely to flow in or out of the soft water tank or neutralization tank in which the corresponding flow path switching valve is installed, so water is extremely unlikely to be sent from the corresponding flow path switching valve.

The energized state of electrode 41 will be described later with reference to FIG. 7 for each process.

The operating states of the temperature detection unit 61 and the performance assurance unit 62 will be described later with reference to Figure 7 for each process.

(Water softening process)
First, the operation of the water softening device 1 during the water softening process will be described with reference to the column "water softening" in FIG. 2 and FIG.

In the water softening device 1, as shown in FIG. 7, in the water softening process, the on-off valve 19 provided in the flow path 28 is opened while the on-off valve 18 is closed. This allows raw water containing hardness components to flow in from the outside. The inflowing raw water flows through the first soft water tank 3a, the first neutralization tank 4a, the second soft water tank 3b, and the second neutralization tank 4b in this order, so that the water softening device 1 can take out softened water (neutral soft water) from the water intake 7. At this time, the flow path switching valve 24 is in a connected state in which water can be sent from the flow path 28 to the flow path 29, the flow path switching valve 25 is in a connected state in which water can be sent from the flow path 29 to the flow path 30, the flow path switching valve 26 is in a connected state in which water can be sent from the flow path 30 to the flow path 31, and the flow path switching valve 27 is in a connected state in which water can be sent from the flow path 31 to the flow path 32. All of the on-off valves 20 to 23 are in a closed state. Furthermore, the electrodes 41a and 41b of the electrolytic cell 9, the first water pump 11, and the second water pump 12 are also stopped.

In addition, during the water softening process, the temperature detection unit 61 is in an operating state and detects the temperature of the raw water flowing into the first soft water tank 3a from the inlet 2. This raw water temperature information is sent to the control unit 15.

In the water softening process, the raw water temperature information sent from the temperature detection unit 61 to the control unit 15 is compared with a predetermined temperature by the temperature comparison unit 64. The operation restriction unit 65 controls the operation of the performance assurance unit 62 based on the result of this comparison. Specifically, if the raw water temperature is equal to or higher than the predetermined temperature, the operation restriction unit 65 does not activate the performance assurance unit 62 (see the "Raw water temperature equal to or higher than predetermined temperature during softening" column in FIG. 7). On the other hand, if the raw water temperature is lower than the predetermined temperature, the operation restriction unit 65 activates the performance assurance unit 62 (see the "Raw water temperature lower than predetermined temperature during softening" column in FIG. 7).

When the performance assurance unit 62 is activated, the performance assurance unit 62 activates the flow rate adjustment unit 63, which then reduces the flow rate of the raw water flowing into the first soft water tank 3a to a predetermined flow rate. The specific operations of the temperature detection unit 61, performance assurance unit 62, and flow rate adjustment unit in the water softening process will be described later.

Specifically, as shown in FIG. 2, in the softening process, the raw water is supplied from the inlet 2 to the first soft water tank 3a through the temperature detection unit 61, the performance guarantee unit 62, and the flow path 28 by the pressure of the raw water flowing in from the outside. The raw water supplied to the first soft water tank 3a flows through the first weakly acidic cation exchange resin 33a provided in the first soft water tank 3a. At this time, the cations, which are hardness components in the raw water, are adsorbed by the action of the first weakly acidic cation exchange resin 33a, 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 contains a large amount of hydrogen ions that have been exchanged with the hardness components and have flowed out, so it is acidified and becomes acidic water (first soft water) with a low pH. Here, when water contains a large amount of permanent hardness components (e.g., sulfates such as calcium sulfate or chlorides such as magnesium chloride) as hardness components, the pH is more likely to drop when softening than water that contains a large amount of temporary hardness components (e.g., carbonates such as calcium carbonate). Since softening is difficult when the pH is low, the water that has passed through the first softening tank 3a is passed through the first neutralization tank 4a for neutralization.

The softened water flows through the flow path 29 via the flow path switching valve 24 provided in the first softening tank 3a and flows into the first neutralization tank 4a. In the first neutralization tank 4a, hydrogen ions contained in the softened water are adsorbed by the action of the first weakly basic anion exchange resin 34a. In other words, hydrogen ions are removed from the water softened by the first softening tank 3a, so the lowered pH rises and is neutralized. Therefore, the softening process in the second softening tank 3b proceeds more easily than when the water softened in the first softening tank 3a is directly softened in the second softening tank 3b.

The water neutralized in the first neutralization tank 4a (neutralized first soft water) flows through the flow path 30 via the flow path switching valve 25 provided in the first neutralization tank 4a and flows into the second soft water tank 3b. In the second soft water tank 3b, the action of the second weakly acidic cation exchange resin 33b adsorbs cations, which are hardness components, and releases hydrogen ions. The second soft water tank 3b exchanges hardness components that could not be removed in the first soft water tank 3a with hydrogen ions held by the second weakly acidic cation exchange resin 33b. In other words, the water that flows into the second soft water tank 3b is further softened to become soft water (second soft water).

The second soft water flows through the flow path 31 via the flow path switching valve 26 provided in the second soft water tank 3b, and flows into the second neutralization tank 4b. In the second neutralization tank 4b, the hydrogen ions contained in the second soft water that flows in are adsorbed by the action of the second weakly basic anion exchange resin 34b. In other words, as the hydrogen ions are removed from the second soft water, the lowered pH increases, and the water becomes neutral soft water (neutralized second soft water) that can be used as domestic water. The neutralized second soft water flows through the flow path 32 via the flow path switching valve 27 provided in the second neutralization tank 4b, and can be taken out from the water intake 7.

In other words, in the softening process, the raw water flows through the first softening tank 3a, the first neutralization tank 4a, the second softening tank 3b, and the second neutralization tank 4b in that order. As a result, the raw water containing hardness components flows out of the first softening tank 3a before the pH of the raw water decreases due to the softening process in the first softening tank 3a, and is neutralized in the first neutralization tank 4a, softened in the second softening tank 3b, and neutralized in the second neutralization tank 4b. Therefore, compared to the case where the softening tank and the neutralization tank are each configured as a single unit, the decrease in pH of the water flowing through the softening tank, i.e., acidification, can be suppressed, so that the exchange of hardness components with hydrogen ions held by the weakly acidic cation exchange resin 33 in the softening tank (especially the second softening tank 3b) occurs more easily. Therefore, it is possible to improve the softening performance.

In addition, during the water softening process, the temperature detection unit 61, performance assurance unit 62, and flow rate adjustment unit 63 operate to prevent the raw water from deteriorating in softening performance under low temperature conditions.

Specifically, as shown in FIG. 2, in the water softening process, the pressure of the raw water flowing in from the outside causes the raw water to pass through the temperature detection unit 61 from the inlet 2. At this time, the temperature detection unit 61 detects the raw water temperature, and the detected raw water temperature information is sent to the control unit 15. The raw water temperature information sent to the control unit 15 is compared with a predetermined temperature by the temperature comparison unit 64, and the operation restriction unit 65 controls the performance assurance unit 62 based on the comparison result.

When the temperature of the raw water is equal to or higher than a predetermined temperature, the operation restriction unit 65 does not activate the performance assurance unit 62, and the flow rate adjustment unit 63 does not activate either. At this time, the flow rate of the raw water supplied to the first soft water tank 3a is not restricted by the flow rate adjustment unit 63, and the raw water flows through the first weakly acidic cation exchange resin 33a provided in the first soft water tank 3a. If the temperature is equal to or higher than the predetermined temperature, sufficient ion exchange reaction occurs in the weakly acidic cation exchange resin 33, even if the raw water flow rate is not restricted, and the target softening performance is achieved.

On the other hand, when the temperature of the raw water is below a predetermined temperature, the operation restriction unit 65 activates the performance assurance unit 62, and the performance assurance unit 62 activates the flow rate adjustment unit 63. At this time, the flow rate of the raw water supplied to the first soft water tank 3a by the flow rate adjustment unit 63 is suppressed to a predetermined flow rate. Then, the raw water flows through the first weakly acidic cation exchange resin 33a provided in the first soft water tank 3a. If the raw water flow rate is not suppressed when the temperature is below a predetermined temperature, the contact time between the weakly acidic cation exchange resin 33 and the raw water required for sufficient ion exchange reaction to occur in the weakly acidic cation exchange resin 33 cannot be secured, and the target softening performance cannot be achieved. However, by suppressing the raw water flow rate to a predetermined flow rate using the flow rate adjustment unit 63, the contact time between the weakly acidic cation exchange resin 33 and the raw water required for sufficient ion exchange reaction to occur can be secured, and the target softening performance can be achieved even under low temperature conditions.

The water softening device 1 terminates the water softening process and executes the regeneration process when the time period specified by the control unit 15 arrives or when the amount of water treated in the water softening process exceeds a certain amount.

(Regeneration process)
Next, the operation of the regeneration device 8 of the water softening device 1 during the regeneration process will be described in order with reference to FIG. 3 and the column "During regeneration" in FIG.

In the water softening device 1, the first soft water tank 3a and the second soft water tank 3b filled with the weakly acidic cation exchange resin 33 will lose or lose their cation exchange capacity with continued use. That is, 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. Even before all of the hydrogen ions are exchanged with hardness components, the ion exchange reaction becomes more difficult as the hydrogen ions decrease, and the water softening performance decreases. In this state, hardness components will be contained in the treated water. For this reason, in the water softening device 1, it becomes necessary to perform a regeneration process of the first soft water tank 3a, the second soft water tank 3b, the first neutralization tank 4a, and the second neutralization tank 4b using the regeneration device 8.

During the regeneration process, the control unit 15 switches the operation to a state consisting of the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 shown in Figure 3.

The soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 shown in Figure 3 will be described. In the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40, the on-off valve 19, the on-off valve 20, and the on-off valve 22 are closed, the on-off valve 18, the on-off valve 21, and the on-off valve 23 are opened, the flow path switching valve 24 is in a connected state where water can be sent from the neutralization tank bypass flow path 42 to the first recovery flow path 37, the flow path switching valve 25 is in a connected state where water can be sent from the soft water tank bypass flow path 44 to the second recovery flow path 38, the flow path switching valve 26 is in a connected state where water can be sent from the first supply flow path 35 to the neutralization tank bypass flow path 42, and the flow path switching valve 27 is in a connected state where water can be sent from the second supply flow path 36 to the soft water tank bypass flow path 44. In other words, the first soft water tank 3a and the second soft water tank 3b are connected in communication, the first neutralization tank 4a and the second neutralization tank 4b are connected in communication, and drainage from the drain outlet 13 and the capture section drain outlet 14 is stopped. As a result, as shown in Figure 3, a soft water tank regeneration circulation flow path 39 and a neutralization tank regeneration circulation flow path 40 are formed, respectively.

Then, when the first water supply pump 11 and the second water supply pump 12 are operated, the acidic electrolyzed water and the alkaline electrolyzed water in the electrolytic cell 9 circulate through the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40, respectively.

In addition, during the regeneration process, the temperature detection unit 61 is not in operation.

As shown in FIG. 3, when the soft water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 are formed, the electrode 41a is energized so that it has a higher potential than the electrode 41b (positive operation). That is, the electrode 41a functions as an anode, and the electrode 41b functions as a cathode. As a result, during electrolysis, hydrogen ions are generated at the electrode 41a (anode), and acidic electrolyzed water is produced near the electrode 41a (anode). Meanwhile, hydroxide ions are generated at the electrode 41b (cathode), and alkaline electrolyzed water is produced at the electrode 41b (cathode).

The acidic electrolyzed water generated in the electrolytic bath 9 flows through the first supply flow path 35, is fed into the second soft water bath 3b through the flow path switching valve 26, and flows through the second weakly acidic cation exchange resin 33b therein. The acidic electrolyzed water that has flowed through the second soft water bath 3b flows through the neutralization bath bypass flow path 42, is fed into the first soft water bath 3a through the flow path switching valve 24, and flows through the first weakly acidic cation exchange resin 33a therein. That is, by passing the acidic electrolyzed water through the weakly acidic cation exchange resin 33, the cations (hardness components) adsorbed on the weakly acidic cation exchange resin 33 undergo an ion exchange reaction with the hydrogen ions contained in the acidic electrolyzed water. This regenerates the weakly acidic cation exchange resin 33.

Then, the acidic electrolyzed water that has flowed through the first soft water tank 3a contains cations and flows into the first recovery flow path 37. That is, the acidic electrolyzed water that contains cations that has flowed through the weakly acidic cation exchange resin 33 is recovered in the electrolytic cell 9 via the first recovery flow path 37.

In this way, the soft water tank regeneration circulation flow path 39 is configured to circulate the acidic electrolyzed water from the downstream side of the second soft water tank 3b, which is the soft water tank located most downstream from the raw water inlet and has the second weakly acidic cation exchange resin 33b that adsorbs less hardness components than the upstream soft water tank, and to flow into the downstream side of the first soft water tank 3a, which is located upstream and has the first weakly acidic cation exchange resin 33a that adsorbs more hardness components than the second soft water tank 3b. In other words, the soft water tank regeneration circulation flow path 39 is a flow path that circulates the acidic electrolyzed water sent from the electrolytic cell 9 through the second soft water tank 3b, then sends it to the first soft water tank 3a through the neutralization cell bypass flow path 42, circulates it through the first soft water tank 3a, and flows into the electrolytic cell 9 via the first recovery flow path 37. As a result, during the regeneration process, the acidic electrolyzed water discharged from the electrolytic cell 9 flows into the second soft water tank 3b, which has a smaller amount of adsorbed hardness components than the first soft water tank 3a, and the acidic electrolyzed water containing hardness components is discharged from the second soft water tank 3b to the first soft water tank 3a. In the regeneration of the weakly acidic cation exchange resin 33 in the second soft water tank 3b, less hydrogen ions are consumed in the acidic electrolyzed water than in the first soft water tank 3a, so the reduction in hydrogen ion concentration can be suppressed compared to the regeneration of the first soft water tank 3a. Therefore, it is possible to suppress the flow of acidic electrolyzed water containing a large amount of hydrogen ions into the first soft water tank 3a, and to suppress the re-adsorption of hardness components in the first soft water tank 3a. Therefore, the decrease in the efficiency of the regeneration process can be suppressed, and the regeneration time can be shortened.

On the other hand, the alkaline electrolyzed water generated near the cathode of the electrolytic cell 9 flows through the second supply flow path 36 and the capture unit 10, is fed into the second neutralization cell 4b through the flow path switching valve 27, and flows through the second weakly basic anion exchange resin 34b inside. The alkaline electrolyzed water that has flowed through the second neutralization cell 4b flows through the soft water tank bypass flow path 44, is fed into the first neutralization cell 4a through the flow path switching valve 25, and flows through the first weakly basic anion exchange resin 34a inside. That is, by passing the alkaline electrolyzed water through the weakly basic anion exchange resin 34, the anions adsorbed on the weakly basic anion exchange resin 34 undergo an ion exchange reaction with the hydroxide ions contained in the alkaline electrolyzed water. This regenerates the weakly basic anion exchange resin 34.

Then, the alkaline electrolyzed water that has flowed through the first neutralization tank 4a contains anions and flows into the second recovery flow path 38. That is, the alkaline electrolyzed water that has flowed through the weakly basic anion exchange resin 34 and contains anions is recovered in the electrolytic tank 9 via the second recovery flow path 38.

In this way, the neutralization tank regeneration circulation flow path 40 is configured to allow the alkaline electrolyzed water to flow from the downstream side of the second neutralization tank 4b, which is the neutralization tank located at the most downstream from the inlet of the raw water and has the second weakly basic anion exchange resin 34b that adsorbs less anions than the upstream neutralization tank, and to flow into the downstream side of the first neutralization tank 4a, which is located at the upstream and has the first weakly basic anion exchange resin 34a that adsorbs more anions than the second neutralization tank 4b. In other words, the neutralization tank regeneration circulation flow path 40 is a flow path that allows the alkaline electrolyzed water sent from the electrolytic tank 9 to flow through the second neutralization tank 4b, then to be sent to the first neutralization tank 4a through the soft water tank bypass flow path 44, to flow through the first neutralization tank 4a, and to flow into the electrolytic tank 9 through the second recovery flow path 38. As a result, during the regeneration process, alkaline electrolyzed water flows into the second neutralization tank 4b, which has a smaller amount of anions adsorbed than the first neutralization tank 4a, and alkaline electrolyzed water containing anions is discharged from the second neutralization tank 4b to the first neutralization tank 4a. In the regeneration of the weakly basic anion exchange resin 34 in the second neutralization tank 4b, the consumption of hydroxide ions in the alkaline electrolyzed water is smaller than that in the first neutralization tank 4a, so the reduction in hydroxide ion concentration can be suppressed compared to the regeneration of the first neutralization tank 4a. Therefore, it is possible to suppress the alkaline electrolyzed water containing a large amount of hydroxide ions from flowing into the first neutralization tank 4a, and the re-adsorption of anions in the first neutralization tank 4a. Therefore, it is possible to suppress the decrease in regeneration efficiency and shorten the regeneration time.

The neutralization tank regeneration circulation flow path 40 introduces the alkaline electrolyzed water sent from the electrolytic tank 9 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 discharges it from the upstream side where the amount of anions adsorbed is greater than that of the downstream side of each neutralization tank. As a result, the alkaline electrolyzed water flows in from the downstream side where the amount of anion components adsorbed is smaller, and the neutralization tank is regenerated. In the regeneration of the weakly basic anion exchange resin 34 on the downstream side, the hydroxide ion consumption in the alkaline electrolyzed water is smaller than that on the upstream side, so that the reduction in the hydroxide ion concentration of the alkaline electrolyzed water can be suppressed. Therefore, the re-adsorption of the anions contained in the alkaline electrolyzed water from the downstream side on the upstream side can be suppressed. Therefore, the decrease in the regeneration efficiency of the neutralization tank can be suppressed, and the regeneration time can be shortened. The downstream side refers to the downstream side in the flow path during the water softening process.

Then, in the water softening device 1, when the time period specified by the control unit 15 is reached or when the regeneration process exceeds a certain period of time (e.g., 4 hours), the regeneration process is terminated and the regeneration flow path cleaning process is performed.

If a user wishes to obtain water during the regeneration process, the user can open a faucet (not shown) connected to the water softener 1, and the raw water will flow from the inlet 2 through the flow path 53 and out of the water intake 7, allowing the user to use the raw water without waiting for the regeneration process to finish.

(Regeneration flow path cleaning process)
Next, the operation of the water softening device 1 during the regeneration flow passage cleaning process will be described in sequence with reference to FIG. 4 and the section "During regeneration flow passage cleaning" in FIG.

In the water softener 1, during the regeneration process, hardness components are released from the first soft water tank 3a and the second soft water tank 3b into the acidic electrolytic water, and the acidic electrolytic water circulates in the flow path without being discharged from the soft water tank regeneration circulation flow path 39. Therefore, after the regeneration process is completed, the soft water tank regeneration circulation flow path 39 is filled with high-hardness water containing hardness components released from the first soft water tank 3a and the second soft water tank 3b. The hardness of this high-hardness water is significantly higher than the hardness of the raw water (e.g., 450 ppm), and may increase to, for example, about 2000 ppm. If the soft water process is started while this high-hardness water remains in the water softener 1, high-hardness water or a mixture of raw water and high-hardness water is discharged from the water intake 7. Therefore, if the user of the water softener 1 performs the soft water softening process after the regeneration process is completed, a problem occurs in that not only is soft water not obtained immediately after the start of the soft water softening process, but water with a higher hardness than the raw water is obtained. In addition, the high hardness water flows through the weak acid cation exchange resin 33 in the first soft water tank 3a and the second soft water tank 3b. Although the hardness components adsorbed in the regeneration process were replaced with hydrogen ions to perform regeneration, water containing hardness components flows again, and an exchange reaction occurs between the hydrogen ions filled by the regeneration process and the hardness components, causing the hardness components to be adsorbed again by the weak acid cation exchange resin 33. Therefore, the hydrogen ions available for softening the raw water are reduced, and the softening performance is reduced. To solve these problems, a regeneration flow path cleaning process is performed to drain the high hardness water from the soft water tank regeneration circulation flow path 39.

During the regeneration flow path cleaning step, the on-off valves 21 to 23 are closed, the on-off valves 18 to 20 are opened, the flow path switching valve 24 is in a connected state in which water can be sent from the flow path 28 to the neutralization tank bypass flow path 42, the flow path switching valve 25 is in a connected state in which water can be sent to the soft water tank bypass flow path 44, the flow path switching valve 26 is in a connected state in which water can be sent from the neutralization tank bypass flow path 42 to the first supply flow path 35, and the flow path switching valve 27 is in a connected state in which water can be sent to the second supply flow path 36. That is, the first soft water tank 3a and the second soft water tank 3b are in a connected state, the second soft water tank 3b and the drain port 13 are in a connected state, the electrolytic tank 9 and the drain port 13 are in a connected state, and the drainage of the capture section drain port 14 is stopped. As a result, a first drainage flow path 46 and a second drainage flow path 47 are formed, as shown in FIG. At this time, the electrodes 41, the first water pump 11, and the second water pump 12 are stopped. During the regeneration process, the temperature detection unit 61 is not in operation.

Specifically, in the regeneration flow path cleaning process, raw water from the outside flows into the first drainage flow path 46 and the second drainage flow path 47 by opening the on-off valve 19.

In the first drainage flow path 46, the pressure of the raw water that flows in sweeps away the high-hardness water in the flow path 28, the first recovery flow path 37, the first water supply pump 11, the electrolytic cell 9, and the first supply flow path 35, and it flows into the drainage flow path 54. The high-hardness water that flows into the drainage flow path 54 is discharged outside the device from the drain outlet 13.

In the second drainage flow path 47, the pressure of the raw water that flows in sweeps away the high-hardness water in the flow path 28, the first soft water tank 3a, the neutralization tank bypass flow path 42, the second soft water tank 3b, and the first supply flow path 35, and it flows into the drainage flow path 54. The high-hardness water that flows into the drainage flow path 54 is discharged outside the device from the drain outlet 13.

In this way, the regeneration flow path cleaning process can replace the high hardness water in the first drainage flow path 46 and the second drainage flow path 47, which are the main remaining areas of high hardness water after the regeneration process, with raw water while suppressing flow to the neutralization tank. Therefore, in the regeneration flow path cleaning process, it is possible to suppress the adsorption of hydrogen ions to the weakly basic anion exchange resin 34 in the neutralization tank, thereby suppressing consumption of the filled hydroxide ions and maintaining neutralization performance. Therefore, it is possible to suppress the deterioration of water softening performance caused by high hardness water.

In addition, the control unit 15 supplies raw water to each flow path so that the flow rate of raw water flowing through the second drainage flow path 47 is greater than the flow rate of raw water flowing through the first drainage flow path 46.

This allows the high hardness water in the second drainage flow path 47, which is a flow path including a soft water tank used during the water softening process and is a flow path in which it is essential to drain the high hardness water in the flow path, to be preferentially replaced with raw water. Therefore, it is possible to suppress the deterioration of the water softening performance caused by high hardness water when the water softening process is started. In addition, it is possible to reduce the amount of water discharged from the first drainage flow path 46, which is a flow path that is not used during the water softening process and has little effect on the water softening process even if high hardness water remains, so that it is possible to prevent unnecessary discharge and suppress the amount of water required for the regeneration flow path cleaning process.

This also allows the high-hardness water to be discharged outside the device through a flow path that does not include a neutralization tank. In other words, the hardness components in the high-hardness water stored in the soft water tank regeneration circulation flow path 39 can be discharged while suppressing adsorption to the weakly basic anion exchange resin 34 in the neutralization tank, preventing a decrease in water softening performance caused by high-hardness water generated during the regeneration process and maintaining water softening performance.

Then, in the water softening device 1, when the time period specified by the control unit 15 is reached, or when the regeneration flow path cleaning process exceeds a certain time (e.g., 1 minute), or when the amount of water passing through the regeneration flow path cleaning process exceeds a certain value, the regeneration flow path cleaning process is terminated and the electrolytic cell cleaning process is carried out.

If a user wishes to obtain soft water during the regeneration flow path cleaning process, the user can open a faucet (not shown) connected to the water softening device 1, and the raw water will flow from the inlet 2 through the flow path 53 and out of the water intake 7, allowing the user to use the raw water without waiting for the completion of the regeneration flow path cleaning process.

((Electrolytic bath cleaning process))
Next, the operation of the water softening device 1 during the electrolytic cell cleaning step will be described in sequence with reference to FIG. 5 and the section "During electrolytic cell cleaning" in FIG.

When the electrolytic cell 9 is operating during the regeneration process, hardness components in the water (calcium ions or magnesium ions) are precipitated as a solid (scale) on the cathode. Because the precipitates that precipitate on the cathode are non-conductors, they increase the operating voltage of the electrolytic cell 9, which in turn increases the power consumption during the regeneration process. Therefore, it is necessary to carry out an electrolytic cell cleaning process to remove the precipitates that have precipitated on the cathode.

In the electrolytic bath cleaning process, the on-off valves 18 to 22 are opened, and the on-off valve 23 is closed. In addition, the flow path switching valve 24 is in a connected state that allows water to be sent from the flow path 28 to the flow path 29, the flow path switching valve 25 is in a connected state that allows water to be sent to the soft water bath bypass flow path 44, the flow path switching valve 26 is in a connected state that allows water to be sent to the first supply flow path 35, and the flow path switching valve 27 is in a connected state that allows water to be sent to the second supply flow path 36. In other words, the first soft water bath 3a and the electrolytic bath 9 are in a connected state, the electrolytic bath 9 is in a connected state with the drain 13, and the electrolytic bath 9 is in a connected state with the capture unit drain 14. In addition, in the electrolytic bath cleaning process, the temperature detection unit 61 is not in an operating state.

Specifically, in the electrolytic cell cleaning process, the on-off valve 19 is opened, causing raw water from the outside to flow into the first drainage flow path 46 and the third drainage flow path 50.

In the first drainage flow path 46, the raw water flows through the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first recovery flow path 37, and the first water supply pump 11, and then flows into the electrolytic cell 9.

Meanwhile, in the third drainage flow path 50, the raw water flows through the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the second recovery flow path 38, and the second water supply pump 12, and then flows into the electrolytic cell 9.

During the electrolytic cell cleaning process, the control unit 15 applies electricity to electrode 41b so that it has a higher potential than electrode 41a.

At this time, the electrolytic cell 9 electrolyzes the raw water that has flowed into the electrolytic cell 9, producing alkaline electrolyzed water at the electrode 41a (cathode) and acidic electrolyzed water at the electrode 41b (anode).

At this time, the acidic electrolyzed water generated by the electrode 41b can dissolve the precipitates that have deposited on the electrode. This makes it possible to suppress the deterioration of electrolysis performance caused by the adhesion of precipitates to the surface of the electrode 41b.

The alkaline electrolyzed water generated by the electrode 41a flows through the first supply flow path 35, enters the drainage flow path 54, and is discharged outside the device through the drain outlet 13.

Meanwhile, the acidic electrolyzed water generated by the electrode 41b dissolves the deposits deposited on the cathode and flows through the second supply flow path 36 into the capture unit 10. The acidic electrolyzed water that flows into the capture unit 10 can dissolve the deposits that have adhered to the capture unit 10, and can preliminarily clean the capture unit 10. This can shorten the time required for the next process, the capture unit cleaning process. The acidic electrolyzed water is then discharged outside the device from the capture unit drain 14 provided at the bottom of the capture unit 10.

In other words, in the electrolytic cell cleaning process, the precipitates in the electrolytic cell 9 and the precipitates in the capture section 10 can be removed simultaneously, shortening the time required from the end of the regeneration process to the start of the water softening process.

Then, in the water softening device 1, when the time period specified by the control unit 15 is reached or when the electrolytic cell cleaning process exceeds a certain period of time (e.g., 5 minutes), the electrolytic cell cleaning process is terminated and the capture unit cleaning process is carried out.

In addition, in the third drainage flow path 50, the raw water passes through the first soft water tank 3a, and the acidic water passes through the capture unit 10. As a result, the capture unit 10 becomes acidic, and the precipitates attached to the capture unit 10 are dissolved by the acidic water. Therefore, the capture unit 10 can be preliminarily cleaned, and the time required for the next process, the capture unit cleaning process, can be shortened. In other words, the precipitates in the electrolytic cell 9 and the precipitates in the capture unit 10 can be removed simultaneously, and the time required from the end of the regeneration process to the start of the water softening process can be shortened.

If a user wishes to obtain water during the electrolytic cell cleaning process, the user can open a faucet (not shown) connected to the water softener 1, and the raw water will flow from the inlet 2 through the flow path 53 and out of the water intake 7, allowing the user to use the raw water without waiting for the electrolytic cell cleaning process to finish.

((Capture part cleaning process))
Next, the operation of the water softening device 1 during the capture unit cleaning process will be described in sequence with reference to FIG. 6 and the section "During capture unit cleaning" in FIG.

In the regeneration process, the electrolytic cell 9 is supplied with high-hardness water containing hardness components released from the first soft water tank 3a and the second soft water tank 3b. The hardness components move to the cathode during electrolysis and react with hydroxide ions generated at the cathode to form precipitates. A part of the precipitate is contained in the alkaline electrolyzed water released from the electrolytic cell 9, flows through the second supply flow path 36, and is captured by the capture unit 10. Therefore, since the precipitate gradually accumulates in the capture unit 10 during the regeneration process, the pressure loss caused by the capture unit 10 gradually increases, and the flow rate of the alkaline electrolyzed water flowing through the neutralization tank regeneration circulation flow path 40 gradually decreases. Therefore, if the precipitate is left, the time required for regeneration of the weakly basic anion exchange resin 34 of the first neutralization tank 4a and the second neutralization tank 4b will be extended, and ultimately, there is a risk that the weakly basic anion exchange resin 34 will not be filled with hydroxide ions. Therefore, a capture unit cleaning process must be carried out to remove any deposits that have adhered to or precipitated on the capture unit 10.

In the capture section cleaning process, the on-off valves 18, 19, 22, and 23 are opened, and the on-off valves 20 and 21 are closed. In addition, the flow path switching valve 24 is in a connected state in which water can be sent from the flow path 28 to the flow path 29, the flow path switching valve 25 is in a connected state in which water can be sent from the flow path 29 to the flow path 30, the flow path switching valve 26 is in a connected state in which water can be sent from the flow path 30 to the flow path 31, and the flow path switching valve 27 is in a connected state in which water can be sent from the flow path 31 to the second supply flow path 36. In other words, the first soft water tank 3a and the first neutralization tank 4a are connected in communication, the first neutralization tank 4a and the second soft water tank 3b are connected in communication, the second soft water tank 3b and the second neutralization tank 4b are connected in communication, and the second neutralization tank 4b and the capture section drain port 14 are connected in communication. As a result, as shown in FIG. 6, a fourth drainage flow path 52 is formed. During the capture unit cleaning process, the temperature detection unit 61 is not in operation.

In the capture unit cleaning process, specifically, raw water flows from the outside into the flow path 28 by opening the on-off valve 19. The raw water flows through the temperature detection unit 61, the performance assurance unit 62, the flow path 28, the first soft water tank 3a, the flow path 29, the first neutralization tank 4a, the flow path 30, the second soft water tank 3b, the flow path 31, the second neutralization tank 4b, and the second supply flow path 36, before flowing into the capture unit 10.

In the capture unit 10, neutral soft water flows in from the opposite side to the water flow direction in the regeneration process. In other words, the capture unit 10 is back-washed by the flowing neutral soft water. At this time, since some of the deposits that have adhered to or deposited on the capture unit 10 in the electrolytic cell cleaning process have already dissolved, the capture unit 10 can be easily washed with neutral soft water. The neutral soft water containing the deposits is discharged outside the device from the capture unit drain 14 provided at the bottom of the capture unit 10.

In this way, the capture unit 10 can be backwashed, and the precipitates remaining in the capture unit 10 can be removed. Therefore, clogging of the capture unit 10 can be suppressed, and the pressure loss caused by the capture unit 10 can be reduced when the regeneration process is performed again. As a result, a reduction in the flow rate of the neutralization tank regeneration circulation flow path 40, which is the regeneration flow path including the capture unit 10, can be suppressed, and the flow rate of the alkaline electrolyzed water can be guaranteed, ensuring regeneration performance.

Then, in the water softening device 1, when the time period specified by the control unit 15 is reached or when the capture unit cleaning process exceeds a certain period of time (e.g., 5 minutes), the capture unit cleaning process ends and the water softening process is carried out.

The flow path from the inlet 2 to the second neutralization tank 4b is the same as the flow path during the water softening process. In other words, by using the fourth drainage flow path 52, the second neutralization tank 4b, which is the final neutralization tank in the water softening process, is filled with softened water. Therefore, by using the fourth drainage flow path 52 to perform the capture unit cleaning process and then the water softening process, the user of the water softening device 1 can obtain soft water with reduced hardness from the water intake 7 immediately after the start of the water softening process.

If a user wishes to obtain water during the capture unit cleaning process, the user can open a faucet (not shown) connected to the water softener 1, and the raw water will flow from the inlet 2 through the flow path 53 and out of the water intake 7, allowing the user to use the raw water without waiting for the capture unit cleaning process to finish.

In this way, the water softening device 1 repeatedly executes the following steps in this order: softening process, mixing process, regeneration process, water storage process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process. By carrying out the capture unit cleaning process immediately before the softening process, the neutralization tank at the final stage in the water softening process is filled with softened water. Therefore, when a user of the water softening device 1 opens the faucet, the discharge of high-hardness water from the water intake 7 can be suppressed, and soft water with a stable hardness can be provided immediately after the start of the water softening process.

In addition, by performing the regeneration flow path cleaning process before the electrolytic cell cleaning process, the high-hardness water has already been discharged outside the device when the electrode is inverted during the electrolytic cell cleaning process, and the possibility of electrolyzing the high-hardness water can be suppressed. Therefore, electrolysis of high-hardness water can be suppressed, and the generation of a large amount of scale in the flow path through which alkaline electrolyzed water is delivered during electrode inversion can be suppressed.

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 that softens raw water containing hardness components using a weakly acidic cation exchange resin 33, a neutralization tank 4 that neutralizes the pH of the soft water that has passed through the water softening tank 3 using a weakly basic anion exchange resin 34, a temperature detection unit 61 that detects the temperature of the raw water flowing into the water softening tank 3, and a performance assurance unit 62 that operates to ensure the ion exchange capacity of the weakly acidic cation exchange resin 33 based on the detection result of the temperature detection unit 61. The performance assurance unit 62 adjusts at least one of the flow rate or temperature of the raw water flowing into the water softening tank 3 when the temperature of the raw water detected by the temperature detection unit 61 is below a predetermined temperature.

This configuration makes it possible to prevent a decrease in the softening performance in the softening tank 3 even when the raw water temperature is lower than a predetermined temperature, and to suppress an increase in the hardness of the discharged softened water.

(2) The performance assurance unit 62 provided in the water softening device 1 includes a flow rate adjustment unit 63 that adjusts the flow rate of raw water flowing into the soft water tank 3, and when the temperature of the raw water is below a predetermined temperature, the flow rate adjustment unit 63 is operated to reduce the flow rate of raw water flowing into the soft water tank 3.

With this configuration, when the raw water temperature is lower than a predetermined temperature, the flow rate of raw water flowing into the soft water tank 3 can be reduced, and the contact time between the raw water and the weakly acidic cation exchange resin 33 can be increased. This makes it possible to suppress a decrease in the efficiency of the ion exchange reaction in the soft water tank 3, and to prevent a decrease in the softening performance. In other words, even if the raw water temperature is lower than a predetermined temperature, an increase in the hardness of the soft water discharged from the soft water tank 3 can be suppressed.

(3) The performance assurance unit 62 provided in the water softening device 1 stops flow rate control by the flow rate adjustment unit 63 when the raw water temperature becomes equal to or higher than a predetermined temperature while the flow rate adjustment unit 63 is operating.

With this configuration, when the raw water temperature reaches or exceeds a predetermined temperature, the operation of the flow rate adjustment unit 63 can be stopped, resulting in a water softening device with low power consumption.

(4) The water softening device 1 is equipped with an operation restriction unit 65 that does not operate the performance assurance unit 62 when the temperature of the raw water detected by the temperature detection unit 61 is equal to or higher than a predetermined temperature.

With this configuration, the performance assurance unit 62 can be operated only when necessary, resulting in a water softening device with low power consumption.

(5) The performance assurance unit 62 provided in the water softening device 1 operates to increase the adsorption rate of raw water hardness components to the weakly acidic cation exchange resin 33 when the temperature of the raw water is below a predetermined temperature.

With this configuration, even when the raw water temperature is lower than a predetermined temperature, it is possible to prevent a decrease in the softening performance in the soft water tank 3, and to suppress an increase in the hardness of the discharged soft water.

(6) The performance assurance unit 62 provided in the water softening device 1 is provided downstream of the temperature detection unit 61 and upstream of the water softening tank 3.

With this configuration, the temperature of the raw water is detected, and the performance assurance unit 62 can adjust the raw water flowing into the soft water tank 3. Even if the raw water temperature is lower than a predetermined temperature, it is possible to prevent a decrease in the soft water softening performance in the soft water tank 3. Therefore, it is possible to suppress an increase in the hardness of the soft water discharged.

(7) The specified temperature in the water softening device 1 is the temperature at which the hardness of the discharged softened water is less than +10% compared to the hardness of the softened water discharged when the water softening operation is performed under the reference temperature conditions.

With this configuration, the performance assurance unit 62 can be activated before the hardness of the soft water becomes 10% or more higher than the hardness of the soft water discharged under the reference temperature conditions. This reduces the possibility that the user of the water softener 1 will use water with high hardness.

(Embodiment 2)
The water softening device 1a according to the second embodiment of the present invention differs from the first embodiment in that the performance assurance unit 62 includes a heating unit 66. Other configurations are the same as those of the water softening device 1 according to the first embodiment. Below, the contents already explained in the first embodiment will not be explained again as appropriate, and the differences from the first embodiment will be mainly explained.

With reference to FIG. 9, the water softening device 1a according to the second embodiment of the present invention will be described. FIG. 9 is a conceptual diagram showing the configuration of the water softening device 1a according to the second embodiment of the present invention. Note that FIG. 9 conceptually shows each element of the water softening device 1a.

(Performance Assurance Department)
The performance assurance unit 62 includes a heating unit 66 that heats the raw water flowing into the first soft water tank 3a. The performance assurance unit 62 is connected to the control unit 15 wirelessly or via wired communication, and the operation of the performance assurance unit 62 is controlled by the control unit 15. When the performance assurance unit 62 is started by the control unit 15, the performance assurance unit 62 starts the heating unit 66, and the heating unit 66 heats the raw water flowing into the first soft water tank 3a to a predetermined temperature or higher.

The predetermined temperature is, for example, 20°C. The hardness of the soft water discharged under the reference temperature conditions during the softening operation is compared with the hardness of the soft water discharged under a certain temperature condition, and the temperature condition is determined to be one in which the hardness of the soft water is 0% to less than +10%. The reference temperature condition is a temperature condition that frequently occurs as the temperature when the water softener 1 is used, for example, 25°C. The softening performance is affected by the ion exchange reaction rate of the weakly acidic cation exchange resin 33 provided in the softening tank 3. In general, the reaction rate is affected by temperature, and under high temperature conditions, the reaction rate increases because ions with energy equal to or greater than the activation energy increase. On the other hand, under low temperature conditions, the reaction rate slows. If the reaction rate is slow, the softening performance in the softening tank 3 decreases, so if the temperature falls below the predetermined temperature, the performance guarantee unit 62 is activated to guarantee the softening performance, thereby suppressing an increase in the hardness of the soft water discharged even under low raw water temperatures.

There are no particular limitations on the heating unit 66, and any general-purpose device can be used, such as an electric heater.

(Water softening process)
First, the operation of the water softening device 1 during the water softening process will be described with reference to the "water softening" column in Figs.

In the water softening device 1, as shown in FIG. 9, in the softening process, the on-off valve 18 is closed and the on-off valve 19 provided in the flow path 28 is opened. This allows raw water containing hardness components to flow in from the outside. The raw water flows through the first soft water tank 3a, the first neutralization tank 4a, the second soft water tank 3b, and the second neutralization tank 4b in that order, so the water softening device 1 can take out softened water (neutral soft water) from the water intake 7. At this time, the flow path switching valve 24 is in a connected state that allows water to be sent from the flow path 28 to the flow path 29, the flow path switching valve 25 is in a connected state that allows water to be sent from the flow path 29 to the flow path 30, the flow path switching valve 26 is in a connected state that allows water to be sent from the flow path 30 to the flow path 31, and the flow path switching valve 27 is in a connected state that allows water to be sent from the flow path 31 to the flow path 32. All of the on-off valves 20 to 23 are in a closed state. Additionally, the electrodes 41a and 41b of the electrolytic cell 9, the first water pump 11, and the second water pump 12 are also stopped.

In addition, during the water softening process, the temperature detection unit 61 is in an operating state and detects the temperature of the raw water flowing into the first soft water tank 3a from the inlet 2. This raw water temperature information is sent to the control unit 15.

In the water softening process, the raw water temperature information sent from the temperature detection unit 61 to the control unit 15 is compared with a predetermined temperature by the temperature comparison unit 64, and the operation restriction unit 65 controls the operation of the performance assurance unit 62 based on the comparison result. If the raw water temperature is equal to or higher than the predetermined temperature, the operation restriction unit 65 does not activate the performance assurance unit 62 (see the "Raw water temperature equal to or higher than predetermined temperature during softening" column in Figure 7). If the raw water temperature is lower than the predetermined temperature, the operation restriction unit 65 activates the performance assurance unit 62 (see the "Raw water temperature lower than predetermined temperature during softening" column in Figure 7).

When the performance assurance unit 62 is activated, the performance assurance unit 62 activates the heating unit 66, and the heating unit 66 heats the temperature of the raw water flowing into the first soft water tank 3a to a predetermined temperature or higher.

The specific operations of the temperature detection unit 61, performance assurance unit 62, and heating unit 66 in the water softening process will be described below. In the water softening process, the temperature detection unit 61, performance assurance unit 62, and heating unit 66 operate to suppress the degradation of the water softening performance under low temperature conditions.

Specifically, as shown in FIG. 9, in the water softening process, the pressure of the raw water flowing in from the outside causes the raw water to pass through the temperature detection unit 61 from the inlet 2. At this time, the temperature detection unit 61 detects the raw water temperature, and the detected raw water temperature information is sent to the control unit 15. The raw water temperature information sent to the control unit 15 is compared with a predetermined temperature by the temperature comparison unit 64, and the operation restriction unit 65 controls the performance assurance unit 62 based on the comparison result.

When the temperature of the raw water is equal to or higher than a predetermined temperature, the operation restriction unit 65 does not activate the performance assurance unit 62, and the heating unit 66 does not activate either. At this time, the raw water supplied to the first soft water tank 3a by the heating unit 66 is not heated, and the raw water flows through the first weakly acidic cation exchange resin 33a provided in the first soft water tank 3a. If the temperature of the raw water is equal to or higher than a predetermined temperature, sufficient ion exchange reaction occurs in the weakly acidic cation exchange resin 33, even if the raw water is not heated, and the target softening performance is achieved.

On the other hand, when the temperature of the raw water is below the predetermined temperature, the operation restriction unit 65 activates the performance assurance unit 62, and the performance assurance unit 62 activates the heating unit 66. At this time, the raw water supplied to the first soft water tank 3a by the heating unit 66 is heated to a predetermined temperature or higher, and the heated raw water flows through the first weakly acidic cation exchange resin 33a provided in the first soft water tank 3a. If the temperature of the raw water is below the predetermined temperature, the ion exchange reaction rate of the weakly acidic cation exchange resin 33 required for sufficient ion exchange reaction to occur in the weakly acidic cation exchange resin 33 cannot be obtained unless the raw water is heated, and the target softening performance cannot be achieved. However, by heating the raw water to a predetermined temperature or higher by the heating unit 66, the ion exchange reaction rate of the weakly acidic cation exchange resin 33 required for sufficient ion exchange reaction to occur can be obtained, and the target softening performance can be achieved even under low temperature conditions.

As described above, the water softening device 1a according to the second embodiment has the following advantages:

(8) The performance assurance unit 62 provided in the water softening device 1a includes a heating unit 66 that heats the raw water flowing into the soft water tank 3, and when the raw water temperature is below a predetermined temperature, the heating unit 66 is operated to heat the raw water so that the temperature of the raw water flowing into the soft water tank 3 is equal to or higher than the predetermined temperature.

With this configuration, the temperature of the raw water flowing into the soft water tank 3 can be adjusted by the heating unit 66, and a decrease in the softening performance in the soft water tank 3 can be prevented even when the raw water temperature is lower than a predetermined temperature. Therefore, an increase in the hardness of the discharged soft water can be suppressed.

(9) The performance assurance unit 62 provided in the water softening device 1a stops heating by the heating unit 66 when the raw water temperature becomes equal to or higher than a predetermined temperature while the heating unit 66 is operating.

With this configuration, when the raw water temperature reaches or exceeds a predetermined temperature, the operation of the heating unit 66 can be stopped, resulting in a water softening device with low power consumption.

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 the water softening device 1 according to the first embodiment, after the regeneration process is completed, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process are performed in this order, but this is not limited to the above. For example, the regeneration flow path cleaning process may be performed after the electrolytic cell cleaning process, or the capture unit cleaning process may be performed before the water softening process. Even if cleaning of the inside of the device is performed in this order, precipitates in the electrolytic cell 9 and the capture unit 10 can be removed, and soft water can be filled into the second neutralization tank 4b immediately before the water softening process.

In the water softening device 1 according to the first embodiment, the softening process, mixing process, regeneration process, water storage process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture section cleaning process are repeatedly performed in this order, but this is not limited to the above. It is not necessary to perform all the processes. For example, the softening process and the regeneration process may be performed alternately, and other processes may be performed as necessary. Even in this way, a water softening device that can repeatedly soften raw water can be obtained.

The water softening device of the present invention can be used as 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), etc.

REFERENCE SIGNS LIST 1, 1a Water softening device 2 Inlet 3 Soft water tank 3a First soft water tank 3b Second soft water tank 4 Neutralization tank 4a First neutralization tank 4b Second neutralization tank 7 Water intake 8 Regeneration device 9 Electrolytic tank 10 Capture unit 11 First water supply pump 12 Second water supply pump 13 Drain 14 Capture unit drain 15 Control unit 18, 19, 20, 21, 22, 23 Opening/closing valve 24, 25, 26, 27 Flow path switching valve 28, 29, 30, 31, 32 Flow path 33 Weakly acidic cation exchange resin 33a First weakly acidic cation exchange resin 33b Second weakly acidic cation exchange resin 34 Weakly basic anion exchange resin 34a First weakly basic anion exchange resin 34b Second weakly basic anion exchange resin 35 First supply flow path 36 Second supply flow path 37 First recovery flow path 38 Second recovery flow path 39 Soft water tank regeneration circulation flow path 40 Neutralization tank regeneration circulation flow path 42 Neutralization tank bypass flow path 43 Water softening flow path 44 Soft water tank bypass flow path 45 Regeneration flow path cleaning flow path 46 First drainage flow path 47 Second drainage flow path 49 Electrolytic cell cleaning flow path 50 Third drainage flow path 51 Capture section cleaning flow path 52 Fourth drainage flow path 53 Flow path 54 Drainage flow path 61 Temperature detection section 62 Performance assurance section 63 Flow rate adjustment section 64 Temperature comparison section 65 Operation restriction section 66 Heating section

Claims (9)

a water softening tank for softening raw water containing hardness components with a weakly acidic cation exchange resin to produce acidic soft water;
a neutralization tank for neutralizing the pH of the soft water that has passed through the soft water tank with a weakly basic anion exchange resin;
A temperature detection unit that detects the temperature of the raw water flowing into the soft water tank;
A performance assurance unit that investigates to ensure the ion exchange capacity of the weak acid cation exchange resin based on the detection result of the temperature detection unit;
The performance assurance unit includes:
A water softening device that adjusts at least one of a flow rate and a temperature of the raw water flowing into the water softening tank when the temperature detected by the temperature detection unit is lower than a predetermined temperature. The performance assurance unit includes:
A flow rate adjusting unit is provided for adjusting the flow rate of the raw water flowing into the soft water tank,
2. The water softening apparatus according to claim 1, wherein, when the temperature is lower than the predetermined temperature, the flow rate adjusting unit is operated to reduce the flow rate of the raw water flowing into the soft water tank. The performance assurance unit includes:
The water softening device according to claim 2 , wherein the flow rate control by the flow rate adjustment unit is stopped when the temperature becomes equal to or higher than the predetermined temperature during operation of the flow rate adjustment unit. The performance assurance unit includes:
A heating unit that heats the raw water flowing into the soft water tank,
2. The water softening device according to claim 1, wherein when the temperature is lower than the predetermined temperature, the heating unit is operated to heat the raw water so that the temperature of the raw water flowing into the soft water tank becomes equal to or higher than the predetermined temperature. The performance assurance unit includes:
The water softening apparatus according to claim 4, wherein heating by the heating unit is stopped when the temperature reaches or exceeds the predetermined temperature during operation of the heating unit. The water softening device according to claim 1, further comprising an operation restriction unit that does not operate the performance assurance unit when the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature. The performance assurance unit includes:
2. The water softening device according to claim 1, wherein the water softening device operates so that an adsorption rate of the hardness components to the weakly acidic cation exchange resin increases when the temperature is lower than the predetermined temperature. The water softening device according to claim 1, wherein the performance assurance unit is provided downstream of the temperature detection unit and upstream of the water softening tank. The water softening device according to claim 1, wherein the predetermined temperature is a temperature at which the hardness of the discharged softened water is less than +10% compared to the hardness of the softened water discharged when the water softening operation is performed under reference temperature conditions.