JP7769856B2 - water softener - Google Patents

Description

The present invention relates to a water softening device.

In conventional water softeners, a known method for regenerating cation exchange resins without using salt is to regenerate the cation exchange resins using acidic electrolyzed water (see, for example, Patent Document 1). Weakly acidic cation exchange resins have protons at the terminals of their functional groups, and soften the raw water by exchanging hardness components (e.g., calcium ions, magnesium ions) in the raw water for hydrogen ions. The raw water softened by the weakly acidic cation exchange resins contains hydrogen ions and is acidic. The hydrogen ions in this softened water are adsorbed by weakly basic anion exchange resins, thereby neutralizing the softened raw water. In conventional water softeners, a known method for regenerating weakly basic anion exchange resins is to regenerate the weakly basic anion exchange resins using alkaline electrolyzed water (see, for example, Patent Document 2).

JP 2011-30973 A JP 2010-142674 A

In such conventional water softening devices, raw water is typically used during electrolysis, but when raw water with low conductivity is used, the voltage applied between the electrodes in the electrolytic cell becomes high. As a result, the electrodes in the electrolytic cell wear out in a short period of time, making it difficult to stably supply acidic electrolyzed water and alkaline electrolyzed water over a long period of time.

One way to prevent this is to add chemicals such as sodium sulfate to the raw water to increase its conductivity, but this creates the problem of having to supply chemicals.

The present invention aims to solve the above problems by providing a water softening device that can increase the conductivity of water supplied to an electrolytic cell without adding chemicals and suppress an increase in the voltage applied to the electrodes.

To achieve this objective, the water softening device of the present invention includes a water softening tank that uses a weakly acidic cation exchange resin to soften raw water containing hardness components used in the water softening process, an electrolytic tank that uses a weakly acidic cation exchange resin in the regeneration process to produce acidic electrolyzed water that regenerates the weakly acidic cation exchange resin in the water softening tank, a mixing section that mixes raw water with regenerated water containing hardness components released by the weakly acidic cation exchange resin during the regeneration process to produce mixed water, a raw water inlet flow path that supplies raw water to the mixing section, and a regenerated water inlet flow path that supplies regenerated water to the mixing section . The electrolytic tank produces acidic electrolyzed water from the mixed water. The mixing section performs mixing by merging the raw water inlet flow path and the regenerated water inlet flow path. This achieves the desired objective.

The present invention provides a water softening device that can increase the conductivity of water supplied to an electrolytic cell without adding chemicals and suppress an increase in the voltage applied to the electrodes.

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 the water softening flow path of the water softening device according to the first embodiment. FIG. 3 is a configuration diagram showing the softened 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 a water storage flow path of the water softening device according to the first embodiment. FIG. 5 is a diagram showing a regeneration flow path cleaning flow path of the water softening device according to the first embodiment. FIG. 6 is a conceptual diagram showing an electrolytic cell cleaning flow path of the water softening device according to the first embodiment. FIG. 7 is a configuration diagram showing the trap section cleaning flow path of the water softening device according to the first embodiment. FIG. 8 is a configuration diagram showing a raw water introduction flow path and a supply flow path of the water softening device according to the first embodiment. FIG. 9 is a configuration diagram showing a control method for the water softening device according to the first embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are examples of specific embodiments of the present invention and do not limit the technical scope of the present invention. Furthermore, the figures described in the embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the figures 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) introduced into the device through an inlet 2, such as city water or well water. The raw water contains hardness components (e.g., calcium ions or magnesium ions). By performing a water softening treatment using the water softening device 1, neutral soft water with reduced hardness is obtained, making it possible to use soft water 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 water softening tank 3, a neutralization tank 4, a water intake 7, a regeneration device 8, a control unit 15, and a mixing unit 60.

The water softening device 1 also includes a drain outlet 13, multiple on-off valves (on-off valve 18, on-off valve 19, on-off valve 20, on-off valve 21, on-off valve 22, on-off valve 23, and on-off valve 63), and multiple flow path switching valves (flow path switching valves 24-27). These will be described in more detail below.

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

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

In the water softening device 1, during the water softening process, raw water supplied from the outside flows through the inlet 2, flow path 28, first softening tank 3a, flow path 29, first neutralization tank 4a, flow path 30, second softening tank 3b, flow path 31, second neutralization tank 4b, flow path 32, and water intake 7 in that order, before being discharged as neutral softened water.

<Soft water tank>
The water softener tank 3 softens raw water containing hardness components through 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. In the water softener 1 of the first embodiment, a first softener tank 3a and a second softener tank 3b are provided as the water softener tanks 3.

The first softening tank 3a softens the raw water flowing in from the inlet 2 through the action of the first weakly acidic cation exchange resin 33a filled inside. The first softening tank 3a is equipped with a flow path switching valve 24. Details of the flow path switching valve will be discussed later.

The second water softening tank 3b softens the water that has passed through the first neutralization tank 4a (described below) through the action of the second weakly acidic cation exchange resin 33b filled inside. The second water softening 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 referred to as the weakly acidic cation exchange resin 33 unless there is a need to distinguish between them.

The weakly acidic cation exchange resin 33 is an ion exchange resin that has hydrogen ions at the end of its functional group. It adsorbs cations (calcium ions, magnesium ions) that are hardness components contained in the raw water passed through it and releases hydrogen ions. Soft water treated with the weakly acidic cation exchange resin 33 contains many hydrogen ions that have been exchanged for 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 acidic soft water (acidic soft water) that contains many hydrogen ions.

Because the terminal functional groups of the weakly acidic cation exchange resin 33 are hydrogen ions, the weakly acidic cation exchange resin 33 can be regenerated using acidic electrolyzed water in the regeneration process described below. During this process, 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 restrictions on the weakly acidic cation exchange resin 33, and a general-purpose one can be used, such as one that uses a carboxyl group (-COOH) as the exchange group. Furthermore, the hydrogen ion (H+), which is the counter ion of the carboxyl group, may be replaced with a cation such as a metal ion or ammonium ion (NH4+).

<Neutralization tank>
The neutralization tank 4 neutralizes the pH of the softened water containing hydrogen ions (acidified softened water) coming out of the softened water tank 3 by the action of the weakly basic anion exchange resin 34 filled therein, to produce neutral softened water. Specifically, the neutralization tank 4 adsorbs the hydrogen ions contained in the softened water from the softened water tank 3 together with anions (negative ions), thereby increasing the pH of the softened water and making it neutral softened water. In the water softening apparatus 1 of the first embodiment, a first neutralization tank 4a and a second neutralization tank 4b are provided as the neutralization tanks 4.

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

The second neutralization tank 4b neutralizes the acidic softened water that has flowed through the second softened water tank 3b through the action of the second weakly basic anion exchange resin 34b packed inside. 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 referred to as the weakly basic anion exchange resin 34 unless there is a 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 can be regenerated using alkaline electrolyzed water in the regeneration process described below.

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

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

The regeneration device 8 is composed of an electrolytic tank 9, a capture unit 10, a first water pump 11, and a second water pump 12. The regeneration device 8 is further configured such that a first supply flow path 35, a second supply flow path 36, a first recovery flow path 37, and a second recovery flow path 38 are connected to the second softening tank 3b, the second neutralization tank 4b, the flow path 28, and the flow path 29, respectively. Details of each flow path are described below. 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 softening tank bypass flow path 44 form the softening tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40, which will be described below.

＜＜Electrolytic cell＞＞
The electrolytic bath 9 generates and discharges acidic electrolyzed water and alkaline electrolyzed water by electrolyzing the water flowing in using a pair of electrodes 41 (electrodes 41a and 41b) installed inside. More specifically, hydrogen ions are generated by electrolysis at the electrode 41a, which serves as an anode during electrolysis in the regeneration process, to generate acidic electrolyzed water. Meanwhile, hydroxide ions are generated by electrolysis at the electrode 41b, which serves as a cathode during electrolysis in the regeneration process, to generate alkaline electrolyzed water. The electrolytic bath 9 supplies acidic electrolyzed water to the first soft water bath 3a and the second soft water bath 3b via the first supply flow path 35 and the neutralization bath bypass flow path 42, and supplies alkaline electrolyzed water to the first neutralization bath 4a and the second neutralization bath 4b via the second supply flow path 36 and the soft water bath bypass flow path 44. Although details will be described later, the acidic electrolyzed water produced 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 produced 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 state of current flow 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 that circulates alkaline electrolyzed water through the neutralization tank regeneration/circulation flow path 40 (see Figure 3). The second water supply pump 12 is provided in the second recovery flow path 38 that connects the first neutralization tank 4a and the electrolytic tank 9. This arrangement is because it makes it easier to circulate alkaline electrolyzed water through the neutralization tank regeneration/circulation flow path 40 using only the second water supply pump 12.

In addition, the first water pump 11 and the second water pump 12 are connected to the control unit 15 (described later) via wireless or wired communication.

<<Capturing section>>
The capture section 10 is provided in a second supply flow path 36 that connects the electrolytic bath 9 and the second neutralization bath 4b.

The capture unit 10 captures precipitates contained in the alkaline electrolyzed water delivered from the electrolytic cell 9. The precipitates are reaction products generated in the electrolytic cell 9 when cations (hardness components) released from the first soft water tank 3a and the second soft water tank 3b during the regeneration process react with the alkaline electrolyzed water. More specifically, while water is being electrolyzed in the electrolytic cell 9, 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 migrate toward the cathode (electrode 41b). Because alkaline electrolyzed water is being generated on the cathode side, the hardness components react with the alkaline electrolyzed water to form precipitates. For example, if the hardness component is calcium ion, mixing with alkaline electrolyzed water can result in a reaction to produce calcium carbonate or calcium hydroxide. The precipitates derived from the hardness components are then captured as precipitates by the capture unit 10 provided in the second supply flow path 36. Furthermore, by capturing precipitates derived from hardness components in the capture unit 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 softened water delivered from the second neutralization tank 4b, which would be caused by the precipitates accumulated in the second neutralization tank 4b reacting with the hydrogen ions released from the first and second soft water tanks 3a and 3b and ionizing them.

In addition, during the regeneration process, the alkaline electrolyzed water, from which 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, which is then 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, thereby reducing the amount of hardness components flowing into the first soft water tank 3a and the second soft water tank 3b, and preventing a decrease in the regeneration efficiency of the weakly acidic cation exchange resin 33.

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

The capture unit 10 can take any form as long as it can separate the precipitates resulting from the reaction between hardness components and alkaline electrolyzed water. Examples include a cartridge-type filter, a filtration layer using granular filter media, a cyclone-type solid-liquid separator, and a hollow fiber membrane.

A commonly used form of 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 a combination of these.

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

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

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

<Water storage tank after regeneration>
The regenerated water storage tank 64 is a tank that stores high-hardness water (regenerated water) remaining in the soft water tank regeneration circulation flow path 39 after the regeneration process. As will be described in detail later, the soft water tank regeneration circulation flow path 39 after the regeneration process contains regenerated water, which is water containing a large amount of hardness components released from the soft water tank 3. By storing this regenerated water and mixing it with raw water to produce mixed water, the electrolytic tank 9 can be filled with mixed water with high electrical conductivity during the next regeneration process.

The regenerated water storage tank 64 is connected to the mixing section 60 via the regenerated water inlet flow path 62, allowing the regenerated water in the tank to be sent to the mixing section 60.

The regenerated water storage tank 64 can be installed anywhere within the soft water tank regeneration circulation flow path 39, but it is preferable to install it downstream of the electrolytic cell 9 and upstream of the second soft water tank 3b, starting from the electrolytic cell 9 in the soft water tank regeneration circulation flow path 39. By locating it in this manner, the regenerated water can be stored while minimizing the impact of the regenerated water on the water softening process. Furthermore, since the acidic regenerated water can be stored, it can be prevented from being adsorbed onto the downstream weakly acidic cation exchange resin 33, and the burden on the electrodes 41 during electrolysis can be reduced compared to when neutral water is electrolyzed.

<Mixing section>
The mixing unit 60 mixes the raw water with regenerated water generated during the regeneration process described below to produce mixed water. The mixing unit 60 produces mixed water with a higher electrical conductivity than the raw water. The resulting mixed water is supplied to the electrolytic cell 9 via a supply flow path 72.

The mixing section 60 is connected to the regenerated water storage tank 64 via a regenerated water inlet flow path 62.

The mixing section 60 can be installed anywhere within the soft water tank regeneration circulation flow path 39, but it is preferable that it be installed downstream of the electrolytic cell 9 and upstream of the second soft water tank 3b, with the electrolytic cell 9 being the starting point in the soft water tank regeneration circulation flow path 39.

<On-off valve and flow path switching valve>
A plurality of on-off valves (on-off valves 18 to 23 and on-off valve 63) 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, on-off valve 23, and on-off valve 63) start or stop the flow of water to each flow path by opening and closing the valve.

On-off valves 20 and 22 are opened during the regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process described below, allowing the regenerated circulating water to be discharged outside the device.

Multiple 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 multiple flow path switching valves has three openings: the first opening is an inlet/outlet through which water can flow in and out; the second opening is an inlet that functions as an inlet but not an outlet; and the third opening is an outlet that functions as an outlet but not an inlet. For each of the multiple flow path switching valves, the inlet/outlet is always "open." Depending on the water flow direction, when either the inlet or outlet is "open," the other inlet or outlet is "closed." By providing flow path switching valves 24 to 27, the number of on-off valves required for each flow path within the water softening device 1 can be reduced, thereby reducing the cost of the water softening device 1.

In addition, the multiple on-off valves (on-off valves 18 to 23 and on-off valve 63) and the multiple flow path switching valves (flow path switching valves 24 to 27) are each connected to the control unit 15 (described below) via wires or wirelessly so that they can communicate with each other.

<Drain port>
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 during the regeneration path cleaning process and the electrolytic cell cleaning process. An on-off valve 20 is provided upstream of the drain outlet 13, and water can be discharged from the drain outlet 13 by opening the on-off valve 20.

<Control unit>
The control unit 15 controls the execution of each of the processes, namely, the water softening process, the mixing process, the regeneration process, the water storage process, the regeneration flow path cleaning process, the electrolytic cell cleaning process, and the capture unit cleaning process, and controls switching between the processes.

Specifically, the control unit 15 controls switching from the water softening process to the mixing process, switching from the mixing process to the regeneration process, switching from the regeneration process to the water storage process, switching from the water storage process to the regeneration flow path cleaning process, switching from the regeneration flow path cleaning process to the electrolytic cell cleaning process, switching from the electrolytic cell cleaning process to the capture unit cleaning process, and 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, and controls 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 flow path switching valves 24 to 27, on-off valve 18, on-off valve 19, on-off valve 21, on-off valve 23, and on-off valve 63 to switch the flow path.

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

<<Post-regenerated water introduction channel>>
The regenerated water introduction flow path 62 is a flow path that supplies the regenerated water to the regenerated water storage tank 64 after the regeneration process is completed, and supplies the regenerated water to the mixing section 60 during the mixing process described below.

The regenerated water introduction flow path 62 is a flow path that connects the mixing section 60, which is connected to the first supply flow path 35, with the regenerated water storage tank 64, and is equipped with an on-off valve 63. After the regeneration process is completed, the regenerated water introduction flow path 62 introduces the regenerated water remaining in the soft water tank regeneration circulation flow path 39, particularly the first supply flow path 35, into the regenerated water storage tank 64 when the on-off valve 63 is opened. During the mixing process, the regenerated water introduction flow path 62 introduces the regenerated water stored in the regenerated water storage tank 64 into the mixing section 60 when the on-off valve 63 is opened.

<<Water softening channel>>
2, the softening flow path 43 formed during the water softening process of the water softening device 1 will be described. FIG. 2 is a structural diagram showing the softening flow path 43 of the water softening device 1.

The water softening flow path 43 (hatched arrow in Figure 2) is a flow path that softens the raw water. The raw water that flows through the water softening flow path 43 becomes neutral soft water and is discharged outside the device through the water intake 7.

The water softening flow path 43 is formed by the inlet 2, flow path 28, first water softening tank 3a, flow path 29, first neutralization tank 4a, flow path 30, second water softening tank 3b, flow path 31, second neutralization tank 4b, flow path 32, and water intake 7.

The flow path 28 connects the inlet 2 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 inlet 2 to the first soft water tank 3a.

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

The flow path 30 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 water neutralized in the first neutralization tank 4a to the second soft water tank 3b.

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

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

As shown in FIG. 2, an on-off valve 19 is installed on the flow path 28 downstream of the inlet 2 and upstream of the first soft water tank 3a. An on-off valve 18 is also installed in the flow path 53, which will be described later. Closing the on-off valve 18 and opening the on-off valve 19 connects the first soft water tank 3a to the inlet 2. The flow path switching valve 24 is switched to connect the first soft water tank 3a to the first neutralization tank 4a, the flow path switching valve 25 is switched to connect the second soft water tank 3b to the second neutralization tank 4b, the flow path switching valve 26 is switched to connect the first neutralization tank 4a to the second soft water tank 3b, and the flow path switching valve 27 is switched to connect the second soft water tank 3b to the second neutralization tank 4b. This forms a water softening flow path 43 that connects the inlet 2 through flow path 28, first softening tank 3a, flow path 29, first neutralization tank 4a, flow path 30, second softening tank 3b, flow path 31, second neutralization tank 4b, flow path 32, and water intake 7. At this time, on-off valves 20, 21, and 23 are closed.

<<Regenerative circulation flow path>>
Next, with reference to Fig. 3, a description will be given of a softened 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. Fig. 3 is a configuration diagram showing the softened 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 Figure 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 then 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 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 acidic electrolyzed 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 delivered 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 allows it to flow out from the upstream side, where a greater amount of hardness components are adsorbed than the downstream side of the water softening 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 Figure 3 (black arrow), this is the flow path through which water delivered 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 then 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 supplies alkaline electrolyzed water from the electrolytic cell 9 to the second neutralization cell 4b. The second supply flow path 36 is equipped 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 alkaline electrolyzed 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.

<<Water storage channel>>
Next, the water storage flow path 66 formed during the water storage process of the water softening device 1 will be described with reference to Fig. 4. Fig. 4 is a structural diagram showing the water storage flow path 66 of the water softening device 1.

The water storage flow path 66 is a flow path that sends the regenerated water, which is high-hardness water remaining in the flow path, to the regenerated water storage tank 64 during the water storage process described below.

As shown in Figure 4 (black arrow), the water storage flow path 66 is a flow path that transports the regenerated water in the first supply flow path 35, second soft water tank 3b, neutralization tank bypass flow path 42, first soft water tank 3a, first recovery flow path 37, first water supply pump 11, electrolytic tank 9, first supply flow path 35, and mixing section 60 to the regenerated water storage tank 64 via the regenerated water introduction flow path 62.

<<Regenerated flow path cleaning flow path>>
Next, a description will be given of a regeneration flow path cleaning flow path 45 formed during the regeneration flow path cleaning process of the water softening device 1 with reference to Fig. 5. Fig. 5 is a configuration diagram showing the regeneration flow path cleaning flow path 45 of the water softening device 1.

The regeneration flow path cleaning flow path 45 is a flow path that discharges 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 Figure 5 (white arrow), the first drainage flow path 46 is composed of flow paths connecting the inlet 2 to the first water pump 11, the electrolytic cell 9, the on-off valve 20, and the drainage outlet 13. Specifically, the first drainage flow path 46 is a flow path that circulates raw water flowing in from the inlet 2 through the flow path 28, the first recovery flow path 37, the first water pump 11, the electrolytic cell 9, the drainage flow path 54, the on-off valve 20, and the drainage outlet 13 in this order.

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

As shown in Figure 5 (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 raw water that flows in from the inlet 2 through 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.

It is preferable to control the flow rate of water flowing through the second drainage flow path 47 so that it is greater than the flow rate of water flowing through the first drainage flow path. This allows high-hardness water in the second drainage flow path, which is a flow path that includes a soft water tank used during the water softening process, to be preferentially replaced with raw water. This therefore reduces the impact of high-hardness water when the water softening process begins.

<<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. 6. Fig. 6 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 resulting from hardness components from 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 Figure 6 (black arrow), the third drainage flow path 50 is composed of flow paths connecting the inlet 2 to the first soft water tank 3a, second water pump 12, electrolytic cell 9, on-off valve 21, capture unit 10, on-off valve 22, and capture unit drain outlet 14. Specifically, the third drainage flow path 50 circulates raw water flowing in from the inlet 2 through flow path 28, first soft water tank 3a, second recovery flow path 38, second water pump 12, electrolytic cell 9, second supply flow path 36, on-off valve 21, capture unit 10, and on-off valve 22, in that order, and then discharges it to the outside of the device through the capture unit drain outlet 14. More specifically, in the third drainage flow path 50, raw water flowing in from the inlet 2 flows through flow path 28 into the first soft water tank 3a, where it is converted into acidic soft water. The generated acidic soft water flows through the second recovery flow path 38 and the second water pump 12 into the electrolytic cell 9. The acidic soft water is then circulated through the second supply flow path 36, in the order of on-off valve 21, capture unit 10, and on-off valve 22, dissolving the precipitate in capture unit 10 and discharging it outside the device through the capture unit drain outlet 14.

<<Capture part cleaning flow path>>
Next, a description will be given of a capture part cleaning flow path 51 formed during the capture part cleaning process of the water softening device 1 with reference to Fig. 7. Fig. 7 is a structural diagram showing the capture part cleaning flow path 51 of the water softening device 1.

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

As shown in FIG. 7, 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 outlet 14. Specifically, the capture unit cleaning flow path 51 circulates raw water flowing in from the inlet 2 through flow path 28, the first soft water tank 3a, flow path 29, the first neutralization tank 4a, flow path 30, the second soft water tank 3b, flow path 31, the second neutralization tank 4b, the second supply flow path 36, the on-off valve 23, the capture unit 10, and the on-off valve 22, in that order, and then discharges the raw water from the capture unit drain outlet 14 to the outside of the device.

<<Raw water inlet flow path and supply flow path>>
Next, the raw water inlet flow path 70 and the supply flow path 72 formed during the mixing process described below will be described with reference to Fig. 8. Fig. 8 is a configuration diagram showing the raw water inlet flow path 70 and the supply flow path 72 of the water softening device 1.

First, we will explain the raw water inlet flow path 70. The raw water inlet flow path 70 is a flow path that supplies raw water to the mixing section 60 during the mixing process described below.

As shown in Figure 8 (white arrow), the raw water introduction flow path 70 is a flow path that connects the inlet 2 to the mixing section 60. Specifically, in embodiment 1, this flow path circulates raw water that flows in from the inlet 2 through 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, in that order, before flowing into the mixing section 60.

The supply flow path 72 is a flow path that supplies the mixed water produced by the mixing unit 60 to the electrolytic cell 9 during the mixing process described below.

As shown in Figure 8 (black arrow), the supply flow path 72 is a flow path that connects the mixing unit 60 and the electrolytic cell 9. Specifically, in embodiment 1, this flow path circulates the mixed water produced by the mixing unit 60 through the first supply flow path 35, the second soft water tank 3b, the neutralization tank bypass flow path 42, the first soft water tank 3a, the first recovery flow path 37, and the first water supply pump 11 in that order, before flowing into the electrolytic cell 9.

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

Next, we will explain the operation of the water softening device 1.

<Water softening process, mixing process, regeneration process, water storage process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process>
Next, the water softening process, mixing process, regeneration process, water storage 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. 9. Fig. 9 is a diagram showing the state during operation of the water softening device 1. Note that, hereinafter, the series of steps of the water softening process, mixing process, regeneration process, water storage 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, mixing process, regeneration process, water storage process, regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process, the control unit 15 controls the on-off valves 18 to 23, on-off valve 63, flow path switching valves 24 to 27, electrode 41 of electrolytic cell 9, first water pump 11, and second water pump 12 to switch and achieve the respective flow states, as shown in Figure 9.

Here, "ON" in Figure 9 indicates that the corresponding on-off valve is "open," the electrode 41 is energized, and the corresponding water pump is operating. Blank spaces indicate that the corresponding on-off valve is "closed," the electrode 41 is not energized, and the corresponding water pump is stopped.

In addition, "from (component number) to (component number)" in Figure 9 indicates that the corresponding flow path switching valve connects the 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 the flow paths so that water can be sent from flow path 28 to flow path 29.

In addition, "To (element number)" in Figure 9 indicates a state in which the corresponding flow path switching valve is connected to a flow path in a direction that may send water 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 softening tank or neutralization tank in which the corresponding flow path switching valve is installed, making it extremely unlikely that water will be sent from the corresponding flow path switching valve.

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

As shown in FIG. 9 , in the water softening process, the on-off valve 18 is closed while 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 inflowing 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, allowing the water softener 1 to extract softened water (neutral soft water) from the water intake 7. At this time, the flow path switching valve 24 is connected to allow water to flow from flow path 28 to flow path 29, the flow path switching valve 25 is connected to allow water to flow from flow path 29 to flow path 30, the flow path switching valve 26 is connected to allow water to flow from flow path 30 to flow path 31, and the flow path switching valve 27 is connected to allow water to flow from flow path 31 to flow path 32. The on-off valves 20 to 23 are all closed. Additionally, the electrodes 41 of the electrolytic cell 9, the first water pump 11, and the second water pump 12 are also stopped.

Specifically, as shown in FIG. 1, during the water softening process, raw water is supplied from the inlet 2 through the flow path 28 to the first softening tank 3a by the pressure of the raw water flowing in from the outside. The raw water then flows through the weakly acidic cation exchange resin 33 provided within the first softening tank 3a. During this process, cations, which are hardness components in the raw water, are adsorbed by the weakly acidic cation exchange resin 33, and hydrogen ions are released (ion exchange occurs). The raw water is then softened by the removal of cations from the raw water. Because the softened water contains many hydrogen ions that have been exchanged with hardness components and released, it is acidified and becomes acidic water (first softened water) with a low pH. Water containing a large amount of permanent hardness components (e.g., sulfates such as calcium sulfate or chlorides such as magnesium chloride) is more likely to experience a decrease in pH during softening than water containing a large amount of temporary hardness components (e.g., carbonates such as calcium carbonate). When the pH is low, softening of the water becomes difficult, so 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 flow path 29 via flow path switching valve 24 provided in first water softening tank 3a and into first neutralization tank 4a. In first neutralization tank 4a, hydrogen ions contained in the softened water are adsorbed by the action of weakly basic anion exchange resin 34. In other words, hydrogen ions are removed from the water softened in first water softening tank 3a, causing the lowered pH to rise and become neutralized. Therefore, the softening process in second water softening tank 3b proceeds more easily than when water softened in first water softening tank 3a is directly softened in second water 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 into the second soft water tank 3b. In the second soft water tank 3b, the weakly acidic cation exchange resin 33 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 possessed by the weakly acidic cation exchange resin 33. In other words, the water that flows into the second soft water tank 3b is further softened and becomes soft water (second soft water).

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

In other words, during the water softening process, raw water flows through the first softening tank 3a, first neutralization tank 4a, second softening tank 3b, and second neutralization tank 4b in that order. As a result, 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. The raw water is neutralized in the first neutralization tank 4a, softened in the second softening tank 3b, and neutralized in the second neutralization tank 4b. This prevents the pH of the water flowing through the softening tank from decreasing, i.e., becoming acidic, compared to when the softening tank and neutralization tank are configured separately. This facilitates exchange of hardness components with hydrogen ions held by the weakly acidic cation exchange resin 33 in the softening tank (particularly the second softening tank 5). This improves water softening performance.

The water softening device 1 then terminates the water softening process and executes the mixing 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.

<<Mixing process>>
Next, the operation of the water softening device 1 during the mixing process will be described with reference to the "during mixing" section of FIGS. 8 and 9.

In the water softening device 1, the first soft water tank 3a and second soft water tank 3b, which are filled with weakly acidic cation exchange resin 33, will lose or lose their cation exchange capacity with continued use. Therefore, it becomes necessary to regenerate the soft water tank 3 and neutralization tank 4 using the regeneration process described below.

During the regeneration process, water is electrolyzed in the electrolytic cell 9, and the resulting acidic electrolyzed water and alkaline electrolyzed water are used for regeneration. However, when low-conductivity water, such as raw water, is used during electrolysis, the resistance generated when the same current value is applied is greater than when electrolyzing water with a high conductivity. This increases the voltage applied between the electrodes 41 of the electrolytic cell 9, causing the electrodes 41 to wear out in a short period of time. This shortens the lifespan of the electrolytic cell 9, making it difficult to stably supply acidic electrolyzed water and alkaline electrolyzed water over a long period of time. One possible way to prevent this is to add chemicals such as sodium sulfate to the raw water to increase its conductivity, but this requires the supply of chemicals.

For this reason, in this first embodiment, a mixing process is performed to prepare water with a higher conductivity than the raw water. In the mixing process, regenerated water produced in the previous regeneration process is used.

During the regeneration process, as the regeneration process of the weakly acidic cation exchange resin and the weakly basic anion exchange resin progresses, the hardness of the acidic electrolyzed water increases due to hardness components (e.g., calcium ions and magnesium ions) released from the soft water tank. Therefore, in systems where acidic electrolyzed water with increased hardness is re-electrolyzed and reused in the regeneration process, the hardness of the acidic electrolyzed water increases over time from the start of the regeneration process, resulting in high-hardness water. The hardness component concentration of high-hardness water (regenerated water) after the regeneration process is, for example, approximately 1500 to 2000 ppm. In other words, because regenerated water contains a large amount of hardness components, which are electrolytes, its conductivity can be increased by mixing it with raw water. Therefore, by using regenerated water, the conductivity of the liquid supplied to the electrolytic cell 9 can be increased without adding chemicals such as sodium sulfate, and an increase in the voltage applied to the electrode 41 can be suppressed.

Furthermore, if the water softening process is started while high-hardness water generated in the regeneration process remains in the device, water with a higher hardness than the raw water will be discharged from the water intake 7 at the beginning of the softening process, and the entire amount of regenerated water would have to be drained. However, if the regenerated water is used in the mixing process, the amount of regenerated water discharged can be reduced.

Specifically, in the mixing process, high-hardness water (regenerated water), which is water produced in the previous regeneration process and contains hardness components and has a higher conductivity than the raw water, is mixed with the raw water to produce mixed water. In other words, the regenerated water produced in the nth regeneration process is mixed with raw water in the n+1th mixing process to produce mixed water. Note that n is an integer greater than or equal to 1.

More specifically, as shown in Figure 9, on-off valve 18 and on-off valves 20 to 23 are closed, and on-off valve 19 is opened. This forms the raw water introduction flow path 70, as shown in Figure 8.

During the mixing process, raw water from the outside flows into the raw water inlet channel 70 by opening the on-off valve 19.

In the raw water inlet flow path 70, the pressure of the incoming raw water causes it to flow through flow path 28, first recovery flow path 37, first water supply pump 11, electrolytic cell 9, and first supply flow path 35 in that order, before flowing into the mixing section 60. Also, because the on-off valve 63 is open, the regenerated water stored in the regenerated water storage tank 64 flows into the mixing section 60 via the regenerated water inlet flow path 62. Therefore, in the mixing section 60, the raw water and the regenerated water are mixed, producing mixed water with a higher conductivity than the raw water.

The conductivity of raw water varies depending on the source and quality of the water, but is between 30 and 600 μs/cm, while the conductivity of regenerated water is between 1000 and 3000 μs/cm.

Here, the flow path switching valve 24 is connected to allow water to be sent from the neutralization tank bypass flow path 42 to the first recovery flow path 37, and the flow path switching valve 25 is connected to allow water to be sent from flow path 29 to the soft water tank bypass flow path 44. Furthermore, the flow path switching valve 26 is connected to allow water to 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 connected to allow water to be sent from the soft water tank bypass flow path 44 to the second supply flow path 36. In other words, the first soft water tank 3a and the second soft water tank 3b are connected and communicated. As a result, a supply flow path 72 is formed, as shown in FIG. 8. At this time, the electrode 41, first water pump 11, and second water pump 12 are stopped.

The resulting mixed water is released from the mixing section 60, flows through the first supply flow path 35, the second soft water tank 3b, the neutralization tank bypass flow path 42, the first soft water tank 3a, the first recovery flow path 37, and the first water supply pump 11, and then flows into the electrolytic cell 9.

In this way, the mixing process allows raw water to be mixed with regenerated water to produce mixed water, which can then be supplied to the electrolytic cell 9. Therefore, the voltage applied to the electrolytic cell 9 can be reduced during the regeneration process described below, thereby suppressing wear on the electrode 41.

It is preferable that the proportion of regenerated water in the mixed water be 15% or more; in other words, it is preferable that the proportion of raw water in the mixed water be 85% or less. This increases the ion concentration in the mixed water, thereby increasing the conductivity of the mixed water and achieving a conductivity of 1000 μS/cm or more. This therefore makes it possible to suppress an increase in the voltage applied to electrode 41 during electrolysis in the regeneration process.

Furthermore, it is preferable that the proportion of regenerated water in the mixed water be 25% or less; in other words, it is preferable that the proportion of raw water in the mixed water be 75% or more. This prevents a significant increase in the concentration of hardness components in the mixed water. Therefore, it is possible to prevent the occurrence of a condition in which solids such as calcium carbonate are more likely to precipitate due to the mixed water becoming highly hard. In this case, it is preferable that the conductivity of the mixed water be 3000 μs/cm or less.

In other words, by setting the proportion of regenerated water in the mixed water to between 15% and 25%, the conductivity of the mixed water can be set to 1000-3000 μs/cm, which prevents the voltage applied to electrode 41 from increasing during electrolysis in the regeneration process and prevents the regenerated water from becoming too hard, which could lead to the precipitation of solids such as calcium carbonate.

The water softening device 1 then ends the mixing process and executes the regeneration process when the time period specified by the control unit 15 arrives or when the duration of the mixing process exceeds a certain period of time (e.g., 5 minutes).

<<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 the "Regeneration" column in FIG. 3 and FIG.

In the water softening device 1, the first softening tank 3a and second softening tank 3b, which are filled with weakly acidic cation exchange resin 33, lose or lose their cation exchange capacity with continued use. That is, once all of the hydrogen ions, which are functional groups of the cation exchange resin, have been exchanged for calcium ions or magnesium ions, which are hardness components, ion exchange becomes impossible. Even before all of the hydrogen ions are exchanged for hardness components, the ion exchange reaction becomes more difficult as the hydrogen ions decrease, resulting in a decline in water softening performance. When this occurs, hardness components begin to be contained in the treated water. For this reason, the water softening device 1 requires the regeneration process of the first softening tank 3a, second softening tank 3b, first neutralization tank 4a, and second neutralization tank 4b using the regeneration device 8.

During the regeneration process, on-off valves 19, 20, and 22 are closed, and on-off valves 18, 21, and 23 are opened. The flow path switching valve 24 is set to a connected state that allows water to be sent from the neutralization tank bypass flow path 42 to the first recovery flow path 37. The flow path switching valve 25 is set to a connected state that allows water to be sent from the softened water tank bypass flow path 44 to the second recovery flow path 38. The flow path switching valve 26 is set to a connected state that allows water to be sent from the first supply flow path 35 to the neutralization tank bypass flow path 42. The flow path switching valve 27 is set to a connected state that allows water to be sent from the second supply flow path 36 to the softened water tank bypass flow path 44. In other words, the first softened water tank 3a and the second softened 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 unit drain outlet 14 is stopped. As a result, the softened water tank regeneration circulation flow path 39 and the neutralization tank regeneration circulation flow path 40 are formed, as shown in FIG. 3 .

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

The electrolytic cell 9 is energized so that the anode has a higher potential than the cathode (positive electrolysis). As a result, during electrolysis, hydrogen ions are generated at the anode, and acidic electrolyzed water is produced near the anode. Meanwhile, hydroxide ions are generated at the cathode, and alkaline electrolyzed water is produced near the cathode.

The acidic electrolyzed water produced in the electrolytic bath 9 flows through the first supply flow path 35 and is sent to the second soft water bath 3b via the flow path switching valve 26, where it flows through the weakly acidic cation exchange resin 33 inside. The acidic electrolyzed water that has flowed through the second soft water bath 3b flows through the neutralization bath bypass flow path 42 and is sent to the first soft water bath 3a via the flow path switching valve 24, where it flows through the weakly acidic cation exchange resin 33 inside. 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.

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

In this way, the soft water tank regeneration circulation flow path 39 is configured to allow acidic electrolyzed water to flow from the downstream side of the second soft water tank 3b, which is the soft water tank located furthest downstream from the raw water inlet and has weakly acidic cation exchange resin 33 that adsorbs fewer hardness components than the upstream soft water tank, to the downstream side of the first soft water tank 3a, which is located upstream and has weakly acidic cation exchange resin 33 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 allows acidic electrolyzed water delivered from the electrolytic cell 9 to flow through the second soft water tank 3b, then to be delivered to the first soft water tank 3a via the neutralization cell bypass flow path 42, flow through the first soft water tank 3a, and then to flow into the electrolytic cell 9 via the first recovery flow path 37. As a result, during the regeneration process, acidic electrolyzed water discharged from the electrolytic cell 9 flows into the second soft water tank 3b, which adsorbs fewer 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. During 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 decrease in hydrogen ion concentration is suppressed compared to regeneration of the first soft water tank 3a. Therefore, acidic electrolyzed water containing a large amount of hydrogen ions flows into the first soft water tank 3a, and re-adsorption of hardness components in the first soft water tank 3a is suppressed. This suppresses a decrease in regeneration efficiency and shortens regeneration time.

Meanwhile, 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, and is sent to the second neutralization cell 4b via the flow path switching valve 27, where it flows through the weakly basic anion exchange resin 34 inside. The alkaline electrolyzed water that has flowed through the second neutralization cell 4b flows through the soft water cell bypass flow path 44, and is sent to the first neutralization cell 4a via the flow path switching valve 25, where it flows through the weakly basic anion exchange resin 34 inside. That is, by passing alkaline electrolyzed water through the weakly basic anion exchange resin 34, anions adsorbed on the weakly basic anion exchange resin 34 undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water. This regenerates the weakly basic anion exchange resin 34.

The alkaline electrolyzed water that has flowed through the first neutralization tank 4a then 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 alkaline electrolyzed water to flow from the downstream side of the second neutralization tank 4b, which is the neutralization tank located most downstream from the raw water inlet and has weakly basic anion exchange resin 34 that adsorbs fewer anions than the upstream neutralization tank, to the downstream side of the first neutralization tank 4a, which is located upstream and has weakly basic anion exchange resin 34 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 alkaline electrolyzed water delivered from the electrolytic tank 9 to flow through the second neutralization tank 4b, then to be delivered to the first neutralization tank 4a via the soft water tank bypass flow path 44, to flow through the first neutralization tank 4a, and to flow into the electrolytic tank 9 via the second recovery flow path 38. As a result, during the regeneration process, alkaline electrolyzed water flows into the second neutralization tank 4b, which adsorbs fewer anions 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. When regenerating the weakly basic anion exchange resin 34 in the second neutralization tank 4b, compared to the first neutralization tank 4a, less hydroxide ions are consumed in the alkaline electrolyzed water, so the decrease in hydroxide ion concentration can be suppressed compared to regeneration of the first neutralization tank 4a. Therefore, alkaline electrolyzed water containing a large amount of hydroxide ions can be prevented from flowing into the first neutralization tank 4a, and the re-adsorption of anions in the first neutralization tank 4a can be suppressed. This prevents a decrease in regeneration efficiency and shortens the regeneration time.

The neutralization tank regeneration circulation flow path 40 introduces alkaline electrolyzed water delivered from the electrolytic tank 9 into the first and second neutralization tanks 4a and 4b from their downstream sides, and allows it to flow out from the upstream side, where a larger amount of anions are adsorbed, compared to the downstream side of each neutralization tank. This allows alkaline electrolyzed water to flow in from the downstream side, where a smaller amount of anions are adsorbed, to regenerate the neutralization tanks. During regeneration of the weakly basic anion exchange resin 34 on the downstream side, less hydroxide ions are consumed in the alkaline electrolyzed water than on the upstream side, preventing a decrease in the hydroxide ion concentration of the alkaline electrolyzed water. Therefore, it is possible to prevent anions contained in the alkaline electrolyzed water from the downstream side from being re-adsorbed on the upstream side. This prevents a decrease in the regeneration efficiency of the neutralization tanks and shortens the regeneration time. The "downstream side" refers to the downstream side of the flow path during water softening.

The water softening device 1 then terminates the regeneration process and executes the water storage process when the time period specified by the control unit 15 arrives or when the regeneration process exceeds a certain period of time (for example, four hours).

If a user wishes to obtain water during the regeneration process, they can simply 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 the water intake 7, allowing them to use the raw water without waiting for the regeneration process to finish.

<<Water storage process>>
Next, the operation of the water softening device 1 during the water storage process will be described in order with reference to the "water storage" section of FIG. 4 and FIG.

Between the regeneration process and the water softening process, the regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process, which will be described later, are carried out. In all of these processes, raw water is introduced into the soft water tank regeneration circulation flow path 39, and a water storage process is carried out to ensure post-regeneration water for the aforementioned mixing process.

During the water storage process, on-off valves 19 to 23 are closed, on-off valve 63 is open, flow path switching valve 24 is connected to allow water to be sent from the neutralization tank bypass flow path 42 to the first recovery flow path 37, and flow path switching valve 25 is connected to allow water to be sent from flow path 29 to the softened water tank bypass flow path 44. Furthermore, flow path switching valve 26 is connected to allow water to be sent from the first supply flow path 35 to the neutralization tank bypass flow path 42, and flow path switching valve 27 is connected to allow water to be sent from the softened water tank bypass flow path 44 to the second supply flow path 36. This forms the water storage flow path 66 indicated by the black arrow in Figure 4. At this time, the electrode 41, first water pump 11, and second water pump 12 are stopped.

Therefore, the regenerated water remaining in the soft water tank regeneration circulation flow path 39 flows through the soft water tank regeneration circulation flow path 39 and flows into the regenerated water storage tank 64 via the regenerated water introduction flow path 62.

In this way, the water storage process allows the regenerated water in the soft water tank regeneration circulation flow path 39 after the regeneration process to be stored in the regenerated water storage tank 64. Therefore, even if the flow path or electrolytic tank 9 is cleaned between the regeneration process and the water softening process, the regenerated water can be used in the next mixing process.

The water softening device 1 then terminates the water storage process and executes the regeneration flow path cleaning process when the time period specified by the control unit 15 is reached, or when the water storage process exceeds a certain time (e.g., 5 minutes), or when the amount of water stored in the regenerated water storage tank 64 exceeds a certain value.

If a user wishes to obtain water during the water storage process, they 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 the water intake 7, allowing them to use the raw water without waiting for the water storage process to finish.

<<Regeneration flow path cleaning process>>
Next, the operation of the water softening device 1 during the regeneration flow path cleaning process will be described in order with reference to FIG. 5 and the column "During regeneration flow path cleaning" in FIG.

During the regeneration process in the water softener 1, hardness components are released from the first and second softened water tanks 3a and 3b into the acidic electrolyzed water, which circulates within the softened water tank regeneration circulation flow path 39 without being discharged. Therefore, after the regeneration process, the softened water tank regeneration circulation flow path 39 is filled with high-hardness water containing the hardness components released from the first and second softened water tanks 3a and 3b. The hardness of this high-hardness water is significantly higher than the hardness of the raw water (e.g., 450 ppm), and may reach, for example, approximately 2000 ppm. If this high-hardness water remains in the water softener 1 when the softening process begins, high-hardness water or a mixture of raw water and high-hardness water will be discharged from the water intake 7. Therefore, if a user of the water softener 1 performs the water softening process after the regeneration process, they will encounter the problem of not only failing to obtain soft water immediately after the softening process begins, but also obtaining water that is harder than the raw water. To solve these problems, a regeneration flow path cleaning process is carried out to drain the high-hardness water from the soft water tank regeneration circulation flow path 39.

In the water storage process carried out before the regeneration flow path cleaning process, some of the regeneration water in the flow path flows into the regeneration water storage tank 64, but the regeneration flow path cleaning process is carried out to discharge the regeneration water remaining in the flow path after the water storage process.

During the regeneration flow path cleaning process, on-off valves 21 to 23 are closed, on-off valves 18 to 20 are opened, flow path switching valve 24 is in a connected state allowing water to be sent from flow path 28 to neutralization tank bypass flow path 42, flow path switching valve 25 is in a connected state allowing water to be sent to soft water tank bypass flow path 44, flow path switching valve 26 is in a connected state allowing water to be sent from neutralization tank bypass flow path 42 to first supply flow path 35, and flow path switching valve 27 is in a connected state allowing water to be sent to second supply flow path 36. In other words, the first soft water tank 3a and second soft water tank 3b are in a connected state, the second soft water tank 3b is in a connected state with drain outlet 13, the electrolytic cell 9 is in a connected state with drain outlet 13, and drainage from the capture unit drain outlet 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. 5. At this time, the electrode 41, first water pump 11, and second water pump 12 are stopped.

Specifically, during 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 incoming raw water pushes the high-hardness water in the flow path 28, first recovery flow path 37, first water supply pump 11, electrolytic cell 9, and 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 through the drain outlet 13.

In the second drainage flow path 47, the pressure of the incoming raw water pushes 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 through 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 its flow to the neutralization tank 4. Therefore, the regeneration flow path cleaning process can suppress the adsorption of hydrogen ions to the weakly basic anion exchange resin 34 in the neutralization tank 4, thereby suppressing the consumption of the loaded hydroxide ions and maintaining neutralization performance. Therefore, it is possible to suppress a decrease in water softening performance caused by high-hardness water.

The water softening device 1 then terminates the regeneration flow path cleaning process and executes the electrolytic cell cleaning process when a time period specified by the control unit 15 is reached, or when the regeneration flow path cleaning process exceeds a certain time (e.g., one minute), or when the amount of water flowing through the regeneration flow path cleaning process exceeds a certain value.

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

<<Electrolytic bath cleaning process>>
Next, the operation of the water softening device 1 during the electrolytic cell cleaning process will be described in order with reference to the section "Electrolytic Cell Cleaning" in FIG. 6 and FIG.

When the electrolytic cell 9 is operating during the regeneration process, hardness components in the water (calcium ions or magnesium ions) deposit as solids (scale) on the cathode. Because the deposits deposited on the cathode are non-conductors, they increase the operating voltage of the electrolytic cell 9, increasing power consumption during the regeneration process. Therefore, an electrolytic cell cleaning process is required to remove the deposits deposited on the cathode.

During the electrolytic bath cleaning process, on-off valves 18 to 22 are opened, and on-off valve 23 is closed. Furthermore, flow path switching valve 24 is connected to allow water to flow from flow path 28 to flow path 29, flow path switching valve 25 is connected to allow water to flow to the soft water tank bypass flow path 44, flow path switching valve 26 is connected to allow water to flow to the first supply flow path 35, and flow path switching valve 27 is connected to allow water to flow to the second supply flow path 36. In other words, the first soft water tank 3a and electrolytic bath 9 are connected in communication, the electrolytic bath 9 is connected in communication with the drain outlet 13, and the electrolytic bath 9 is connected in communication with the capture unit drain outlet 14. As a result, a first drain flow path 46 and a third drain flow path 50 are formed, as shown in FIG. 6.

Specifically, during the electrolytic cell cleaning process, the on-off valve 19 is opened, allowing 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 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 incoming raw water flows through the flow path 28, the first soft water tank 3a, the second recovery flow path 38, and the second water supply pump 12 before flowing into the electrolytic cell 9.

During the electrolytic cell cleaning process, the control unit 15 applies electricity so that the cathode has a higher potential than the anode (reverse electrolysis). Therefore, the electrolytic cell 9 electrolyzes the raw water that has flowed into the electrolytic cell, producing alkaline electrolyzed water near the anode and acidic electrolyzed water near the cathode.

At this time, the acidic electrolyzed water produced at the cathode can dissolve the deposits that have formed on the cathode. This prevents a decrease in electrolysis performance due to deposits adhering to the surface of the electrode 41.

The alkaline electrolyzed water produced at the anode flows through the first supply flow path 35, into the drainage flow path 54, and is discharged outside the device through the drain outlet 13.

Meanwhile, the acidic electrolyzed water produced at the cathode 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 dissolves the deposits that have adhered to the capture unit 10, allowing the capture unit 10 to be preliminarily cleaned. This shortens the time required for the next step, the capture unit cleaning step. The acidic electrolyzed water is then discharged outside the device through the capture unit drain outlet 14 located at the bottom of the capture unit 10.

In other words, the electrolytic cell cleaning process can simultaneously remove deposits from the electrolytic cell 9 and the capture unit 10, shortening the time required from the end of the regeneration process to the start of the water softening process.

The water softener 1 then terminates the electrolytic cell cleaning process and executes the capture unit cleaning process when the time period specified by the control unit 15 arrives or when the electrolytic cell cleaning process exceeds a certain time period (e.g., 5 minutes).

In addition, in the third drainage flow path 50, 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 adhering to the capture unit 10 are dissolved by the acidic water. This allows the capture unit 10 to be preliminarily cleaned, thereby shortening the time required for the next process, the capture unit cleaning process. In other words, the precipitates in the electrolytic tank 9 and the capture unit 10 can be removed simultaneously, shortening the time required from the end of the regeneration process to the start of the water softening process.

If a user wishes to obtain water during the electrolytic cell cleaning process, they can simply 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 the water intake 7, allowing them to use the raw water without waiting for the electrolytic cell cleaning process to finish.

<<Capturing unit cleaning process>>
Next, the operation of the water softening device 1 during the trap unit cleaning process will be described in order with reference to the section "During trap unit cleaning" in FIG. 7 and FIG.

During the regeneration process, high-hardness water containing hardness components released from the first soft water tank 3a and the second soft water tank 3b flows into the electrolytic tank 9. The hardness components migrate to the cathode during electrolysis and react with hydroxide ions generated at the cathode, forming precipitates. Some of the precipitates are contained in the alkaline electrolyzed water released from the electrolytic tank 9, circulate through the second supply flow path 36, and are captured by the capture unit 10. Therefore, as precipitates gradually accumulate 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 alkaline electrolyzed water flowing through the neutralization tank regeneration circulation flow path 40 gradually decreases. Therefore, if the precipitates are left unattended, the time required to regenerate the weakly basic anion exchange resins 34 in the first neutralization tank 4a and the second neutralization tank 4b increases, and ultimately, the weakly basic anion exchange resins 34 may not be fully charged with hydroxide ions. Therefore, a capture unit cleaning process is required to remove any deposits that have adhered to or precipitated on the capture unit 10.

During the capture unit cleaning process, on-off valves 18, 19, 22, and 23 are opened, and on-off valves 20 and 21 are closed. Furthermore, flow path switching valve 24 is connected to allow water to flow from flow path 28 to flow path 29, flow path switching valve 25 is connected to allow water to flow from flow path 29 to flow path 30, flow path switching valve 26 is connected to allow water to flow from flow path 30 to flow path 31, and flow path switching valve 27 is connected to allow water to flow from flow path 31 to second supply flow path 36. In other words, the first softened water tank 3a and the first neutralization tank 4a are connected in communication, the first neutralization tank 4a and the second softened water tank 3b are connected in communication, the second softened water tank 3b and the second neutralization tank 4b are connected in communication, and the second neutralization tank 4b and the capture unit drain port 14 are connected in communication. This forms a fourth drainage flow path 52, as shown in FIG. 7 .

Specifically, during the capture unit cleaning process, raw water flows into the flow path 28 from the outside by opening the on-off valve 19. The raw water flows through the flow path 28, the first softening tank 3a, the flow path 29, the first neutralization tank 4a, the flow path 30, the second softening 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.

Neutral soft water flows into the capture unit 10 from the opposite side to the water flow direction during the regeneration process. In other words, the capture unit 10 is back-washed with the flowing neutral soft water. At this time, some of the deposits that had adhered to or deposited on the capture unit 10 during the electrolytic cell cleaning process have already dissolved, making it easy to clean the capture unit 10 with the neutral soft water. The neutral soft water containing the deposits is discharged outside the device through the capture unit drain outlet 14 located at the bottom of the capture unit 10.

In this way, the capture unit 10 can be backwashed, removing any remaining deposits in the capture unit 10. This prevents blockage of the capture unit 10 and reduces pressure loss caused by the capture unit 10 when the regeneration process is performed again. As a result, a decrease in the flow rate of the neutralization tank regeneration circulation flow path 40, which is the regeneration flow path that includes the capture unit 10, can be prevented, and the flow rate of alkaline electrolyzed water can be guaranteed, ensuring regeneration performance.

The water softening device 1 then terminates the capture unit cleaning process and starts the water softening process when the time period specified by the control unit 15 arrives or when the capture unit cleaning process exceeds a certain time period (e.g., 5 minutes).

The flow path from the inlet 2 to the second neutralization tank 4b is the same as the flow path used 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, users of the water softener 1 can obtain softened 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, they can simply 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 the water intake 7, allowing them to use the raw water without waiting for the capture unit cleaning process to finish.

In this way, the water softener 1 repeatedly performs 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 performing the capture unit cleaning process immediately before the water softening process, the neutralization tank, the final stage in the water softening process, is filled with softened water. Therefore, when a user of the water softener 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, high-hardness water has already been discharged outside the device when the polarity is reversed during the electrolytic cell cleaning process, reducing the possibility of electrolyzing high-hardness water. This prevents the electrolysis of high-hardness water and prevents the formation of large amounts of scale in the flow path through which alkaline electrolyzed water is delivered during polarity reversal.

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

(1) The water softener 1 includes a water softener tank 3 that uses a weakly acidic cation exchange resin 33 to soften raw water containing hardness components used in the water softening process; an electrolytic tank 9 that produces acidic electrolyzed water that is used in the regeneration process to regenerate the weakly acidic cation exchange resin 33 in the water softener tank 3; and a mixer 60 that mixes the raw water with regenerated water containing hardness components that precipitated from the weakly acidic cation exchange resin 33 during the regeneration process to produce mixed water. The electrolytic tank 9 then produces acidic electrolyzed water from the mixed water.

With this configuration, electrolysis can be performed using mixed water with a higher conductivity than the raw water, thereby suppressing an increase in the voltage applied to the electrode 41. This suppresses wear on the electrode 41 and extends the service life of the electrolytic cell 9. Furthermore, because the conductivity of the raw water can be increased without adding chemicals, the device can be made smaller, operating costs can be reduced, and the hassle of adding chemicals can be avoided. Furthermore, because the liquid produced by the process in the water softener 1 and discharged can be effectively utilized to prepare water with a higher conductivity than the raw water, the amount of discharged water can be reduced, and the amount of raw water newly introduced during the regeneration process can be reduced.

(2) The water softening device 1 is equipped with a supply flow path 72 that supplies the mixed water generated by the mixer 60 to the electrolytic cell 9. The supply flow path 72 supplies the mixed water to the electrolytic cell 9 at the start of the regeneration process.

With this configuration, mixed water is supplied to the electrolytic cell 9 from the start of the regeneration process, allowing electrolysis of mixed water with a higher conductivity than the raw water. This prevents an increase in the voltage applied to the electrode 41, thereby reducing wear on the electrode 41.

(3) The water softener 1 includes a soft water tank regeneration circulation flow path 39 that connects the electrolytic tank 9 and the soft water tank 3. The mixing section 60 is located downstream of the electrolytic tank 9 and upstream of the soft water tank 3 in the soft water tank regeneration circulation flow path 39, starting from the electrolytic tank 9.

This configuration allows raw water and regenerated water to be mixed while minimizing the impact of either the raw water or the regenerated water on the water softening process. Furthermore, because the acidic regenerated water can be stored, it is possible to prevent adsorption onto the downstream weakly acidic cation exchange resin 33 and reduce the burden on the electrodes during electrolysis compared to when electrolyzing neutral water.

(4) In the water softener 1, the proportion of regenerated water in the mixed water is 15% or more.

By doing this, the ion concentration in the mixed water can be increased, thereby increasing the conductivity of the mixed water. This can therefore suppress the increase in voltage applied to electrode 41 during electrolysis in the regeneration process.

(5) In the water softener 1, the proportion of regenerated water in the mixed water is 25% or less.

By doing this, it is possible to prevent the concentration of hardness components in the mixed water from increasing significantly. This therefore prevents the occurrence of a condition in which solids such as calcium carbonate are more likely to precipitate due to the mixed water becoming highly hard.

(6) The water softening device 1 includes a raw water inlet flow path 70 that supplies raw water to the mixing unit 60, a regenerated water inlet flow path 62 that supplies regenerated water to the mixing unit 60, and a regenerated water storage tank 64 that stores the regenerated water. The mixing unit 60 mixes the raw water supplied from the raw water inlet flow path 70 with the regenerated water supplied from the regenerated water storage tank 64 via the regenerated water inlet flow path 62.

This configuration allows regenerated water to be stored in the regenerated water storage tank 64. Therefore, even if liquid flows into the soft water tank regeneration circulation flow path 39 between regeneration processes, highly conductive regenerated water can be supplied to the mixing section 60 during the mixing process. Furthermore, because acidic regenerated water can be stored, it is possible to prevent adsorption to the downstream weakly acidic cation exchange resin 33 and reduce the burden on the electrodes during electrolysis compared to when electrolyzing neutral water.

(7) The water softening device 1 is equipped with a control unit that repeatedly performs a softening and regeneration process including a water softening process and a regeneration process multiple times, and the electrolytic cell 9 mixes the regenerated water produced during the nth softening and regeneration process with the raw water and uses the mixed water during the n+1th softening and regeneration process.

With this configuration, the regenerated water produced in the previous regeneration process can be mixed with raw water in the next mixing process and used as the mixed water during the regeneration process. Therefore, electrolysis can be performed using mixed water with a higher conductivity than raw water, thereby suppressing an increase in the voltage applied to electrode 41.

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, the regenerated water stored in the regenerated water storage tank 64 is mixed with raw water during the mixing process, but this is not limited to this. For example, raw water may be introduced into the soft water tank regeneration circulation flow path 39 and mixed with the regenerated water in the flow path. Even in this case, raw water flows in through the raw water inlet flow path 70, and the regenerated water flows through the regenerated water inlet flow path. However, in this case, the regenerated water inlet flow path is the flow path equivalent to the soft water tank regeneration circulation flow path 39. Furthermore, when obtaining mixed water in this manner, if the regeneration flow path cleaning process, electrolytic cell cleaning process, and capture unit cleaning process are performed, the regenerated water or mixed water will be diluted with wastewater or raw water outside the device. Therefore, it is preferable to repeat the three steps of the water softening process, mixing process, and regeneration process.

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 this. 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 when cleaning the interior of the device in this order, precipitates in the electrolytic cell 9 and the capture unit 10 can be removed, and softened water can be filled into the second neutralization tank 4b immediately before the water softening process.

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

REFERENCE SIGNS LIST 1 Water softening device 2 Inlet 3 Water softening tank 3a First water softening tank 3b Second water softening tank 4 Neutralization tank 4a First neutralization tank 4b Second neutralization tank 7 Water intake 8 Regeneration device 9 Electrolytic tank 10 Capture unit 11 First water supply pump 12 Second water supply pump 13 Drain outlet 14 Capture unit drain outlet 15 Control unit 18, 19, 20, 21, 22, 23, 63 Opening and 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 41 Electrode 41a Electrode 41b Electrode 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 60 Mixing section 62 Regenerated water introduction flow path 64 Regenerated water storage tank 70 Raw water introduction flow path 72 Supply flow path

Claims (7)

a water softening tank that uses a weakly acidic cation exchange resin to soften raw water containing hard components used in a water softening process;
an electrolytic tank for generating acidic electrolyzed water used in a regeneration step to regenerate the weakly acidic cation exchange resin in the soft water tank;
a mixing section that mixes the raw water with regenerated water containing the hardness components released by the weakly acidic cation exchange resin during the regeneration step to produce mixed water;
a raw water inlet flow path for supplying the raw water to the mixing section;
a regenerated water introduction flow path for supplying the regenerated water to the mixing section;
Equipped with
The electrolytic cell generates the acidic electrolyzed water from the mixed water ,
The mixing section mixes the raw water inlet flow path and the reclaimed water inlet flow path by merging them together.
Water softener. a supply flow path that supplies the mixed water generated by the mixing unit to the electrolytic cell;
The water softening apparatus according to claim 1 , wherein the supply passage supplies the mixed water to the electrolytic cell at the start of the regeneration step. a soft water tank regeneration flow path that connects the electrolytic tank and the soft water tank;
3. The water softening apparatus according to claim 1, wherein the mixing section is provided downstream of the electrolytic bath and upstream of the soft water bath in the soft water bath regeneration flow path, starting from the electrolytic bath. 2. The water softening apparatus according to claim 1 , wherein the proportion of the regenerated water in the mixed water is 15% or more. 2. The water softening apparatus according to claim 1 , wherein the proportion of the regenerated water in the mixed water is 25% or less. a raw water inlet flow path for supplying the raw water to the mixing section;
a regenerated water introduction flow path for supplying the regenerated water to the mixing section;
a regenerated water storage tank for storing the regenerated water,
The water softening apparatus according to claim 1 , wherein the mixing section mixes the raw water supplied from the raw water inlet flow path with the regenerated water supplied from a regenerated water storage tank via the regenerated water inlet flow path. a control unit that repeatedly executes a water softening and regeneration process including the water softening step and the regeneration step a plurality of times;
The electrolytic cell comprises:
The water softening apparatus according to claim 1 , wherein the regenerated water produced during the nth softening regeneration treatment is mixed with the raw water and used as the mixed water during the (n+1)th softening regeneration treatment.