JP2023110825A - Water softening device - Google Patents

Abstract

To provide a water softening device capable of more accurately calculating concentration of a hardness component from electric conductivity of softened water.SOLUTION: A water softening device 1 includes a water softening tank 4, a neutralization tank 5, a softened water detection part 6, an acquisition part 17, a calibration part 18, and a calculation part 19. The water softening tank softens raw water containing a hardness component. The neutralization tank neutralizes a pH of the softened water having passed through the water softening tank. The softened water detection part detects electric conductivity of the softened water having passed through the water softening tank and the neutralization tank. The acquisition part acquires electric conductivity corresponding to ions other than the hardness component in the raw water. The calibration part calibrates the electric conductivity obtained by the softened water detection part on the basis of the electric conductivity corresponding to the ions other than the hardness component in the raw water acquired by the acquisition part, and outputs second electric conductivity. The calculation part calculates the hardness of the softened water on the basis of the second electric conductivity output by the calibration part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water softening device.

In a conventional water softening device using a weakly acidic cation exchange resin, a method of regenerating the cation exchange resin with acidic electrolyzed water generated by electrolysis is known as a method of regenerating the cation exchange resin without using salt. (See Patent Document 1, for example). The weakly acidic cation exchange resin has a hydrogen ion at the end of the functional group, and softens the raw water by exchanging hardness components (eg, calcium ion, magnesium ion) in the raw water with hydrogen ions.

Japanese Unexamined Patent Application Publication No. 2011-30973

Such a water softening device is required to detect the hardness of the soft water in order to grasp whether the water softening is progressing appropriately. In order to detect hardness, it is conceivable to measure the electrical conductivity of water. Contains ions other than components. In addition, since hardness components and ions other than hardness components behave differently in concentration change during water softening, even soft water exhibiting the same electrical conductivity may have different ion concentration ratios. Therefore, there is a problem that it is difficult to accurately calculate the hardness of the soft water from the electric conductivity of the extracted soft water.

SUMMARY OF THE INVENTION An object of the present invention is to provide a water softening apparatus capable of more accurately calculating the hardness of soft water from the electrical conductivity of the soft water.

In order to achieve this object, the water softening device according to the present invention includes a water softening tank, a neutralization tank, a soft water detection section, an acquisition section, a calibration section, and a calculation section. The water softening tank softens raw water containing hardness components with a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the acidic soft water produced by passage through the water softening tank with a weakly basic anion exchange resin. The soft water detector detects electrical conductivity of the neutralized soft water generated by passage through the neutralization tank. The acquisition unit acquires electrical conductivity corresponding to ions other than hardness components in raw water. The calibration unit calibrates the electrical conductivity of the soft water based on the electrical conductivity acquired by the acquisition unit, and outputs a second electrical conductivity. The calculator calculates hardness component information based on the second electrical conductivity.

ADVANTAGE OF THE INVENTION According to this invention, the water softening apparatus which can calculate the density|concentration of a hardness component more correctly from the electrical conductivity of soft water can be provided.

FIG. 1 is a conceptual diagram showing the configuration of a water softening device according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram showing a circulation flow path of the water softening apparatuses according to Embodiments 1 and 2 of the present invention. FIG. 3 is a diagram showing states during operation of the water softening apparatuses according to Embodiments 1 and 2 of the present invention. FIG. 4 is a conceptual diagram showing the configuration of a water softening device according to Embodiment 2 of the present invention. FIG. 5 is a diagram showing changes in electrical conductivity during water softening by the water softening apparatus according to Embodiment 2 of the present invention. FIG. 6 is a conceptual diagram showing a water softening device according to Embodiment 3 of the present invention. FIG. 7 is a diagram showing the state of each component during the resin regeneration process of the water softening device according to Embodiment 3 of the present invention. FIG. 8 is a diagram showing the operating state of the water softening device according to Embodiment 3 of the present invention. FIG. 9 is a functional block diagram showing each configuration of a control section of a water softening device according to Embodiment 3 of the present invention. FIG. 10 is a diagram showing changes in electrical conductivity of softened water by the water softening apparatus according to Embodiment 3 of the present invention. FIG. 11 is a diagram showing changes in ion concentration of softened water by the water softening apparatus according to Embodiment 3 of the present invention.

A water softening device according to the present invention includes a water softening tank, a neutralization tank, a raw water detection section, a soft water detection section, an acquisition section, a calibration section, a calculation section, and a display section. The water softening tank softens raw water containing hardness components with a weakly acidic cation exchange resin. The neutralization tank neutralizes the pH of the softened water that has passed through the water softening tank with a weakly basic anion exchange resin. The raw water detector detects electrical conductivity of raw water. The softened water detector detects electrical conductivity of softened water that has passed through the water softening tank and the neutralizing tank. The acquisition unit acquires electrical conductivity corresponding to ions other than hardness components in raw water. The calibration unit calibrates the electrical conductivity obtained by the soft water detection unit based on the electrical conductivity corresponding to the ions other than the hardness component in the raw water, which is acquired by the acquisition unit, and outputs the second electrical conductivity. . The calculator calculates the hardness of the soft water based on the second electrical conductivity output by the calibrator. The display unit notifies the hardness of the soft water calculated by the calculation unit. The water softener is configured such that raw water flows through the raw water detector, the water softening tank, the neutralization tank, and the softened water detector in this order.

According to such a configuration, the electrical conductivity of the raw water is acquired in the raw water detection unit, and the electrical conductivity of the raw water is corrected (multiplied by a predetermined value, etc.) in the acquisition unit. Acquire the corresponding electrical conductivity (first electrical conductivity), and calibrate the electrical conductivity of the soft water detected by the soft water detection unit based on the electrical conductivity corresponding to the ion component other than the hardness component in the calibration unit. The calculated electrical conductivity (second electrical conductivity) can be acquired, and the hardness component in the soft water can be calculated from the second electrical conductivity in the calculation unit. Therefore, compared to the conventional water softening device, even when hard water containing a mixture of hardness components and other ionic components is circulated, the electrical conductivity of the hard water and the soft water obtained by circulating the hard water can be used to determine the hardness of the soft water. components can be calculated.

Further, in the water softening device according to the present invention, acidic electrolyzed water for regenerating the weakly acidic cation exchange resin in the water softening tank and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin in the neutralization tank and a processing tank for mixing the acidic electrolyzed water that has passed through the water softening tank and the alkaline electrolyzed water that has passed through the neutralizing tank and supplying the mixture to the electrolytic tank. According to such a configuration, it is possible to regenerate the weakly acidic cation exchange resin with the acidic electrolyzed water generated in the electrolytic cell, and it is possible to regenerate the weakly basic anion exchange resin with the alkaline electrolyzed water. Therefore, the maintenance frequency of the water softener can be reduced, and the water softener can be used for a long period of time.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following embodiment is an example that embodies the present invention, and does not limit the technical scope of the present invention. Each drawing described in the embodiment is a schematic drawing, and the ratio of the size and thickness of each component in each drawing does not necessarily reflect the actual dimensional ratio. .

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

<Overall composition>
The water softening device 1 is a device that generates neutral soft water from externally supplied raw water containing hardness components. The raw water is water (water to be treated) introduced into the apparatus from the inflow port 2, and is, for example, city water or well water. Raw water contains hardness components (eg calcium or magnesium ions).

Specifically, as shown in FIG. , a playback device 8 , an acquisition unit 17 , a calibration unit 18 , a calculation unit 19 , a control unit 20 and a display unit 21 . The water softening device 1 also includes a plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, on-off valve 71, and on-off valve 72), the details of which will be described later.

The inflow port 2 is connected to a raw water supply source and a flow path 30 . The inlet 2 is an opening through which raw water is introduced into the device.

The water intake port 7 is an opening through which the neutral soft water treated in the softening tank 4 and the neutralizing tank 5 is discharged out of the apparatus. In the water softening device 1 , softened water can be taken out from the water intake 7 by the pressure of the raw water flowing in from the inlet 2 .

The inlet 2 to the water intake 7 are connected by channels 30 , 31 , 32 , 33 , and 34 .

The channel 30 is a channel that connects the inlet 2 to the first water softening tank 4a. In other words, the flow path 30 is a flow path that guides raw water containing hardness components from the inlet 2 to the first water softening tank 4a.

The flow path 31 is a flow path that connects the first water softening tank 4a to the first neutralization tank 5a. That is, the flow path 31 is a flow path that guides the water softened in the first water softening tank 4a to the first neutralization tank 5a.

The channel 32 is a channel that connects the first neutralization tank 5a to the second water softening tank 4b. That is, the flow path 32 is a flow path that guides the water neutralized in the first neutralization tank 5a to the second water softening tank 4b.

The flow path 33 is a flow path that connects the second water softening tank 4b to the second neutralization tank 5b. That is, the flow path 33 is a flow path that guides the water softened in the second water softening tank 4b to the second neutralization tank 5b.

The flow path 34 is a flow path that connects the second neutralization tank 5b to the water intake port 7. As shown in FIG. That is, the flow path 34 is a flow path that guides the soft water neutralized by the second neutralization tank 5b to the intake port 7. As shown in FIG.

In summary, in the water softening device 1, in the water softening process, the raw water supplied from the outside passes through the inlet 2, the flow path 30, the first water softening tank 4a, the flow path 31, the first neutralization tank 5a, the flow path 32, the second softening tank 4b, the channel 33, the second neutralizing tank 5b, the channel 34, and the water intake 7, and discharged as neutral soft water.

<Water softening tank>
The water softening tank 4 softens raw water containing hardness components by the action of the weakly acidic cation exchange resin 9 . Specifically, the water softening tank 4 exchanges cations (calcium ions, magnesium ions), which are hardness components contained in flowing water (raw water), with hydrogen ions. become The water softening tank 4 is equipped with a weakly acidic cation exchange resin 9 having hydrogen ions at the ends of functional groups.

The water softening tank 4 is composed of, for example, a cylindrical container filled with a weakly acidic cation exchange resin 9 .

The water softening tank 4 includes a first water softening tank 4a and a second water softening tank 4b.

The first water softening tank 4a is filled with a first weakly acidic cation exchange resin 9a. The second water softening tank 4b is filled with a second weakly acidic cation exchange resin 9b. Moreover, it is desirable that the first water softening tank 4a and the second water softening tank 4b have approximately the same channel length, channel cross-sectional area, and volume of the weakly acidic cation exchange resin 9. As shown in FIG. In the following description, the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b will be described as the weakly acidic cation exchange resin 9 when there is no particular need to distinguish between the two.

The weakly acidic cation exchange resin 9 is an ion exchange resin having hydrogen ions at the terminals of functional groups. The weakly acidic cation exchange resin 9 adsorbs cations (calcium ions, magnesium ions), which are hardness components contained in raw water to be passed, and releases hydrogen ions. Since the terminals of the functional groups of the weakly acidic cation exchange resin 9 are hydrogen ions, the weakly acidic cation exchange resin 9 can be regenerated using acidic electrolyzed water in the regeneration treatment described later. At this time, the weakly acidic cation exchange resin 9 releases cations, which are hardness components taken in during the water softening treatment.

As the weakly acidic cation exchange resin 9, there is no particular limitation, and general-purpose resins can be used. Also, the hydrogen ion (H+) of the carboxyl group may be a positive ion such as a metal ion or an ammonium ion (NH4+).

<Neutralization tank>
The neutralization tank 5 neutralizes the pH (hydrogen ion concentration index) of the soft water containing hydrogen ions (acidified soft water) coming out of the water softening tank 4 by the action of the weakly basic anion exchange resin 10, The water should be neutral and soft. Specifically, the neutralization tank 5 absorbs the hydrogen ions contained in the soft water from the water softening tank 4 together with anions (anions), so that the pH of the soft water increases and the water can be neutralized. Further, the weakly basic anion exchange resin 10 can be regenerated using alkaline electrolyzed water in the regeneration treatment described later. Neutralization tank 5 is provided with weakly basic anion exchange resin 10 .

The neutralization tank 5 is composed of, for example, a cylindrical container filled with a weakly basic anion exchange resin 10 .

The neutralization tank 5 includes a first neutralization tank 5a and a second neutralization tank 5b.

The first neutralization tank 5a is configured, for example, by filling a cylindrical container with a first weakly basic anion exchange resin 10a. The second neutralization tank 5b is filled with a second weakly basic anion exchange resin 10b. In addition, it is desirable that the first neutralization tank 5a and the second neutralization tank 5b have approximately the same channel length, channel cross-sectional area, and volume of the weakly basic anion exchange resin 10. . In the following description, the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b are referred to as the weakly basic anion exchange resin 10 when there is no particular need to distinguish between the two. explain.

The weakly basic anion exchange resin 10 neutralizes the hydrogen ions contained in the water that is passed through it to produce neutral water. The weakly basic anion exchange resin 10 is not particularly limited, and a general-purpose resin can be used. For example, a free base resin can be used.

<Raw water detector>
The raw water detection unit 3 is provided in the flow path 30 and detects the electric conductivity of the raw water (raw water electric conductivity) containing the hardness component supplied from the inlet 2 and flowing through the flow path 30 . The raw water detection unit 3 is communicably connected to an acquisition unit 17 and a control unit 20, which will be described later, wirelessly or by wire. Information about the detected raw water electrical conductivity is used as an input signal for the acquisition unit 17 and the control unit 20 . As the raw water detector 3, a general-purpose detector can be used as long as it measures the electrical conductivity of liquid.

Pure water is an insulator that does not conduct electricity. However, dissolution (ionization) of various substances makes it easier to conduct electricity. In other words, the electrical conductivity of a liquid is an index of the amount of ionized substances contained in the liquid. In general raw water, it is proportional to the content of ions that are abundantly contained in river water or groundwater, which is the source of raw water. Examples of anions include chloride ions, nitrate ions, sulfate ions, and the like.

<Soft water detector>
The soft water detection unit 6 is provided in the flow path 34 and detects the electric conductivity of the neutral soft water (soft water electric conductivity) flowing out from the second neutralization tank 5b. The soft water detection unit 6 is communicably connected to an acquisition unit 17 and a control unit 20, which will be described later, wirelessly or by wire. Information about the detected electrical conductivity of soft water is used as an input signal for the acquisition unit 17 and the control unit 20 . As the soft water detector 6, a general-purpose detector can be used as long as it measures the electric conductivity of liquid. For example, a form using an alternating current two-electrode system, an alternating current four-electrode system, and an electromagnetic induction system can be mentioned.

<Playback device>
The regeneration device 8 is a device that regenerates the weakly acidic cation exchange resin 9 in the water softening tank 4 and regenerates the weakly basic anion exchange resin 10 in the neutralization tank 5 . Specifically, the regeneration device 8 includes an electrolytic bath 11 , a treatment bath 13 , and a water pump 14 . Then, the regeneration device 8 provides a first supply channel 41, a first recovery channel 45, a first recovery channel 45, and a A second supply channel 42 and a second recovery channel 46 are connected to each other. Moreover, the channel 31 and the channel 32 are connected by the first bypass channel 43 . Moreover, the channel 32 and the channel 33 are connected by the second bypass channel 44 . Each channel constitutes a circulation channel 40 (a first circulation channel 40a and a second circulation channel 40b), which will be described later.

Here, the first supply channel 41 is a channel for supplying acidic electrolyzed water from the electrolytic bath 11 to the second water softening bath 4b.

The first bypass channel 43 is a channel for bypassing the first neutralization tank 5a and supplying the acidic electrolyzed water that has flowed through the second water softening tank 4b to the first water softening tank 4a.

The first recovery channel 45 is a channel for recovering the acidic electrolyzed water containing hardness components that has passed through the first water softening tank 4 a to the treatment tank 13 .

The second supply channel 42 is a channel for supplying alkaline electrolyzed water from the electrolytic bath 11 to the second neutralizing bath 5b.

The second bypass flow path 44 is a flow path that bypasses the second water softening tank 4b and supplies the alkaline electrolyzed water that has flowed through the second neutralization tank 5b to the first neutralization tank 5a.

The second recovery channel 46 is a channel for recovering the alkaline electrolyzed water that has passed through the first neutralization tank 5 a to the treatment tank 13 .

<Electrolyzer>
The electrolytic cell 11 uses electrodes 12 (electrodes 12a and 12b) provided inside to electrolyze incoming water (water supplied from the treatment cell 13) into acidic electrolyzed water and alkaline electrolyzed water. are generated and emitted. More specifically, at the electrode 12a that serves as an anode during electrolysis, hydrogen ions are generated by electrolysis, and acidic electrolyzed water is generated. Further, at the electrode 12b which becomes a cathode during electrolysis, hydroxide ions are generated by electrolysis, and alkaline electrolyzed water is generated. Then, the electrolytic bath 11 supplies the acidic electrolyzed water through the first supply channel 41 to the second water softening bath 4b. Further, the electrolytic bath 11 supplies alkaline electrolyzed water to the second neutralization bath 5b through the second supply flow path 42 . Although the details will be described later, the acidic electrolyzed water generated by the electrolytic cell 11 is composed of the first weakly acidic cation exchange resin 9a of the first water softening tank 4a and the second weakly acidic cation exchange resin of the second water softening tank 4b. 9b is used for regeneration. In addition, the alkaline electrolyzed water generated by the electrolytic tank 11 is mixed with the first weakly basic anion exchange resin 10a of the first neutralization tank 5a and the second weakly basic anion exchange resin 10b of the second neutralization tank 5b. used for playback. In addition, the electrolytic cell 11 is configured such that the state of energization to the electrode 12 can be controlled by the control unit 20, which will be described later.

<Treatment tank>
The processing tank 13 is a tank or container equipped with an air vent valve 16 . The treatment tank 13 secures and stores water to be circulated in the circulation flow path 40 (see FIG. 2) when the weakly acidic cation exchange resin 9 and the weakly basic anion exchange resin 10 are regenerated. The processing tank 13 mixes the acidic electrolyzed water containing hardness components that has flowed through the water softening tank 4 and the alkaline electrolyzed water containing anions that has flowed through the neutralization tank 5 , and supplies the mixture to the electrolytic tank 11 . be.

In the treatment tank 13, reaction products (reaction products resulting from the hardness components contained in the raw water) are generated by the reaction of the mixed hardness components and the alkaline electrolyzed water. More specifically, acidic electrolyzed water containing hardness components after regenerating the weakly acidic cation exchange resin 9 in the water softening tank 4 flows through the treatment tank 13 through the first recovery channel 45. be done. In addition, in the treatment tank 13, alkaline electrolyzed water containing anions (for example, chloride ions and hydroxide ions) after regenerating the weakly basic anion exchange resin 10 in the neutralization tank 5 is second. Water is passed through the recovery channel 46 . Then, in the treatment tank 13, the acidic electrolyzed water containing hardness components and the alkaline electrolyzed water containing anions are mixed, and the hardness components react with the alkaline electrolyzed water. For example, when the hardness component in the acidic electrolyzed water is calcium ions, mixing with the alkaline electrolyzed water causes a reaction to produce calcium carbonate or calcium hydroxide. Then, the reacted hardness component can be separated as a reaction product by the filtering unit 15, which will be described later, and treated water can be obtained.

It should be noted that the term "hardness component reacts" not only refers to the fact that all hardness components react, but also includes the state in which the processing tank 13 contains components that do not react or components with a concentration that does not exceed the solubility product.

The treated water obtained by the reaction of the hardness components in the treatment tank 13 is passed through the electrolytic tank 11, electrolyzed in the electrolytic tank 11, and converted into acidic electrolyzed water and alkaline electrolyzed water. Each is supplied to the neutralization tank 5 . The acidic electrolyzed water and the alkaline electrolyzed water are reused in the water softening tank 4 and the neutralizing tank 5, respectively, and then passed through the treatment tank 13 again. Therefore, the acidic electrolyzed water and alkaline electrolyzed water used for regeneration of the weakly acidic cation exchange resin 9 and regeneration of the weakly basic anion exchange resin 10 can be reused. Moreover, since the water in which the hardness component has reacted is reused, it is possible to suppress reduction in regeneration efficiency when regenerating the weakly acidic cation exchange resin 9 .

<Water pump>
The water pump 14 is a device that circulates water through the circulation flow path 40 (see FIG. 2) during the regeneration process by the regeneration device 8 . The water supply pump 14 is provided in a water supply channel 50 that communicates and connects between the treatment tank 13 and the electrolytic tank 11 . The water pump 14 is preferably arranged upstream of the electrolytic bath 11 and downstream of the treatment bath 13 . The reason for such an arrangement is that one water pump 14 can easily circulate water in a first circulation flow path 40a and a second circulation flow path 40b, which will be described later. Further, the water pump 14 is communicably connected to a controller 20, which will be described later, wirelessly or by wire. The water pump 14 is, for example, a centrifugal pump capable of supplying a required flow rate of the circulation flow path 40 described later during the regeneration process.

<Filtration section>
Filtration unit 15 is provided in front of water supply channel 50 that connects treatment tank 13 to electrolytic tank 11 . The filtering unit 15 separates precipitates contained in the water flowing through the treatment tank 13 . The precipitate is a reaction product produced by the reaction between the acidic electrolyzed water containing hardness components that has flowed through the water softening tank 4 and the alkaline electrolyzed water that has flowed through the neutralization tank 5 and contains anions.

By separating the precipitates in the filtration unit 15, the treated water flowing through the water supply channel 50 does not contain the precipitates. It is possible to prevent performance deterioration due to deposition of deposits on the membrane of the water softening tank 4 and the inflow of deposits into the neutralization tank 5 .

The filtering part 15 may have any form as long as it can separate the reaction product with the hardness component in the treatment tank 13 . Examples thereof include a form using a cartridge-type filter, a filter layer using granular filter media, a cyclone-type solid-liquid separator, a hollow fiber membrane, and the like.

<On-off valve>
A plurality of on-off valves (on-off valve 51 to on-off valve 55, on-off valve 61 to on-off valve 66, on-off valve 71, and on-off valve 72) are provided in each channel, and each channel is in an "open" state. and the "closed" state. In addition, a plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, on-off valves 71, and on-off valves 72) are connected to the controller 20 described later so as to communicate wirelessly or by wire. ing.

<Acquisition part>
The acquisition unit 17 is connected to the control unit 20 to be described later, corrects the electrical conductivity of the raw water detected by the raw water detection unit 3, and calculates the electrical conductivity corresponding to ions other than hardness components in the raw water (second -Electrical conductivity). As a correction method, multiplication of a predetermined value for the electric conductivity of the raw water can be used. Here, the predetermined value is, for example, the ratio of the electrical conductivity corresponding to the ions other than the hardness component to the electrical conductivity of the raw water. The ratio of the electrical conductivity corresponding to the ions other than the hardness component to the electrical conductivity of the raw water differs depending on the country or region. This is because the ratio of ion components contained in the raw water differs depending on the country or region. However, in the same country or region, the ratio of ion components in the raw water changes little over time. Therefore, by presetting a predetermined value corresponding to the country or region where the water softening device 1 is used and correcting the electrical conductivity of the raw water using this predetermined value, it is possible to originally make it impossible to distinguish between ion component species. In the electrical conductivity measurement, which is a possible method, it is also possible to obtain the electrical conductivity corresponding to ions other than hardness components.

<Calibration department>
The calibrating unit 18 is connected to the control unit 20, which will be described later, and is based on the electrical conductivity (first electrical conductivity) corresponding to the ions other than the hardness component in the raw water, which is acquired by the acquiring unit 17, and the soft water detecting unit 6. Calibrate the electrical conductivity of the soft water obtained in , and output it as the second electrical conductivity.

As a calibration method, for example, there is a method of subtracting the value of the first electric conductivity from the electric conductivity of soft water. When calibrated in this way, the ion components corresponding to the second electrical conductivity are mainly calcium ions and magnesium ions, which are hardness components, and chloride ions, nitrate ions, and sulfate ions which are counter ions of these cations. and excludes monovalent cationic components such as sodium ions and potassium ions. Therefore, by using the second electrical conductivity, the hardness component in the soft water can be calculated in the calculation unit 19, which will be described later.

The reason why the ion component corresponding to the second electrical conductivity is calibrated so as not to contain monovalent cations as described above will be explained using sodium ions as an example. One reason for calibration is the magnitude of the effect of sodium ions on electrical conductivity. The soft water flowing through the soft water detector 6 contains sodium ions. This is because when the raw water is softened by flowing through the weakly acidic cation exchange resin 9 of the water softening tank 4, weakly acidic cation exchange occurs between sodium ions and calcium ions and magnesium ions, which are hardness components. This is due to the difference in susceptibility to an ion exchange reaction with the resin 9 . An ion exchange reaction with the weakly acidic cation exchange resin 9 is less likely to occur with sodium ions, which are monovalent cations, than with calcium ions and magnesium ions, which are divalent cations. Therefore, when water containing these ions is passed through the weakly acidic cation exchange resin 9, calcium ions and magnesium ions are preferentially ion-exchanged. In particular, when the raw water is city water used as domestic water, considering the general ion component ratio, weakly acidic Only when the raw water is circulated through the cation exchange resin 9, only a part of the sodium ions are ion-exchanged. It is not ion-exchanged and is taken out as it is contained in soft water.

Therefore, if the configuration by the calibration unit 18 is not performed, the hardness is calculated based on the electrical conductivity including sodium ions, so it is difficult to accurately calculate the hardness of soft water. Therefore, by performing calibration by the calibration unit 18, it is possible to accurately calculate the hardness of soft water based on the second electrical conductivity, which is the electrical conductivity with reduced influence of monovalent cations such as sodium ions. can.

<Calculation unit>
The calculation unit 19 is connected to the control unit 20 to be described later, corrects the second electrical conductivity output from the calibration unit 18, calculates hardness components in soft water, and outputs hardness component information. The hardness component information includes the hardness component concentration of the neutralized soft water. As a correction method, for example, multiplication of a predetermined value to the second electrical conductivity, or the like can be mentioned. Here, the predetermined value is, for example, a constant of proportionality between the second electrical conductivity and the hardness component in soft water. Generally, the electrical conductivity of water is proportional to the concentration of ionic components in water, and the higher the concentration of ionic components in water, the greater the electrical conductivity. The constants of proportionality for ion concentration and electrical conductivity differ depending on the ion species. In addition to the electrical conductivity due to the hardness component, the second electrical conductivity includes the electrical conductivity due to anions such as chloride ions, nitrate ions, and sulfate ions. By adjusting the setting of the constant of proportionality used as the predetermined value in consideration of the anion composition corresponding to the region in advance, it is possible to calculate the hardness component information in soft water more accurately.

In addition, when the second electrical conductivity is 0 or less, the hardness component concentration in the soft water is calculated as 0. In this case, the hardness of soft water is determined to be zero. The case where the second electrical conductivity is 0 or less is the case where the electrical conductivity of the soft water is equal to the first electrical conductivity, or the case where the electrical conductivity of the soft water is the first electrical conductivity or less. As a specific example of this case, when almost all of the hardness components in the raw water circulating through the raw water detection unit 3 are adsorbed by the weakly acidic cation exchange resin 9 and are not contained in the soft water circulating through the soft water detection unit 6, or Substantially all of the hardness components in the raw water circulating through the raw water detection unit 3 and part of the ions other than the hardness components such as sodium ions are adsorbed by the weakly acidic cation exchange resin 9 or the weakly basic anion exchange resin 10 to detect soft water. There is a case where it is not contained in the soft water flowing through the part.

<Control part>
The control unit 20 controls a water softening process for softening raw water containing hardness components. In addition, the control unit 20 controls regeneration of the weakly acidic cation exchange resin 9 in the water softening tank 4 and the weakly basic anion exchange resin 10 in the neutralization tank 5 . Further, the control unit 20 controls switching of the water softening device 1 among the water softening process, the regeneration process, and the waste water process. At this time, the control unit 20 controls the operation of the electrode 12, the water pump 14, the on-off valves 51 to 55, the on-off valves 61 to 66, the on-off valve 71, and the on-off valve 72, and softens the water and regenerates the water. Processing and wastewater treatment are switched, and each treatment is executed.

The control unit 20 is connected to the acquisition unit 17, the calibration unit 18, the calculation unit 19, and the display unit 21, and the raw water electrical conductivity, the soft water electrical conductivity, the first electrical conductivity, the second electrical conductivity, and the soft water electrical conductivity, respectively. controls the input and output of the hardness component of

Note that the control unit 20 has a computer system having a processor and memory. The computer system functions as a controller by the processor executing the program stored in the memory. Although the program executed by the processor is pre-recorded in the memory of the computer system here, it may be provided by being recorded in a non-temporary recording medium such as an optical disk or a memory card, or may be provided electronically such as the Internet. It may be provided through a communication line.

<Display part>
The display unit 21 is wirelessly or wiredly connected to the control unit 20 and displays information (hardness component information) on the hardness component in the soft water calculated by the calculation unit 19 . The display unit 21 may be a liquid crystal monitor installed on the housing of the water softener 1 or may be a screen of a smart phone possessed by the user of the water softener 1 . Here, the information about the hardness components in the soft water displayed on the display unit 21 is, for example, information indicating the hardness of the soft water as a numerical value, or based on the numerical value of the hardness of the soft water. For example, information indicating whether a group belongs to the group or the like. Thereby, the user of the water softening device 1 can visually know the hardness of the soft water taken out from the water softening device 1 .

<Flow path>
Next, referring to FIG. 2, the circulation flow path 40 formed during the regeneration process of the water softening device 1 will be described. FIG. 2 is a configuration diagram showing the circulation flow path 40 of the water softening device 1. As shown in FIG.

Although the description will be repeated, as shown in FIG. In addition, the electrolytic bath 11 and the treatment bath 13 have a first supply channel 41, a first recovery The channel 45, the second supply channel 42, and the second recovery channel 46 are connected to each other. Further, the flow path 31 and the flow path 32 are bypass-connected by the first bypass flow path 43 . Further, the flow path 32 and the flow path 33 are bypass-connected by the second bypass flow path 44 . Each channel constitutes a circulation channel 40 (a first circulation channel 40a and a second circulation channel 40b), which will be described later.

The first supply channel 41 is a channel for supplying acidic electrolyzed water from the electrolytic tank 11 to the second water softening tank 4b, and an on-off valve 63 is installed in the channel. That is, the water softening device 1 is provided with a first supply channel 41 that allows the acidic electrolyzed water to be extracted from the electrolytic bath 11 and sent to the downstream side of the second water softening bath 4b.

The first bypass channel 43 is a channel for supplying acidic electrolyzed water from the second water softening tank 4b to the first water softening tank 4a, and an on-off valve 65 is installed in the channel. That is, the water softening device 1 includes a first bypass channel 43 that allows the acidic electrolyzed water that has flowed through the second water softening tank 4b to be sent to the downstream side of the first water softening tank 4a. By providing the first bypass channel 43, the regeneration treatment can be performed without circulating the acidic electrolyzed water in the first neutralization tank 5a existing between the first water softening tank 4a and the second water softening tank 4b. can proceed.

The first recovery channel 45 is a channel for recovering the acidic electrolyzed water containing the hardness component that has passed through the first water softening tank 4a to the treatment tank 13, and an on-off valve 61 is installed in the channel. ing. That is, the water softening device 1 includes a first recovery channel 45 that allows the upstream side of the treatment tank 13 to be connected to the upstream side of the first water softening tank 4a.

The second supply channel 42 is a channel for supplying alkaline electrolyzed water from the electrolytic tank 11 to the second neutralization tank 5b, and an on-off valve 64 is installed in the channel. That is, the water softening device 1 is provided with a second supply flow path 42 that draws out the alkaline electrolyzed water from the electrolytic tank 11 and makes it possible to send the water to the downstream side of the second neutralizing tank 5b.

The second bypass channel 44 is a channel for supplying alkaline electrolyzed water from the second neutralization tank 5b to the first neutralization tank 5a, and an on-off valve 66 is installed in the channel. That is, the water softening device 1 includes a second bypass channel 44 that allows the alkaline electrolyzed water that has flowed through the second neutralization tank 5b to be sent to the downstream side of the first neutralization tank 5a.

The second recovery channel 46 is a channel for recovering the alkaline electrolyzed water that has passed through the first neutralization tank 5a to the treatment tank 13, and an on-off valve 62 is installed in the channel. That is, the water softening device 1 is provided with a second recovery channel 46 that allows the upstream side of the treatment tank 13 to be connected to the upstream side of the first neutralization tank 5a.

The circulation flow path 40 includes a first circulation flow path 40 a in which water sent from the treatment tank 13 by the water pump 14 flows through the second water softening tank 4 b and the first water softening tank 4 a, The water sent out from 13 includes the second circulation flow path 40b through which the second neutralization tank 5b and the first neutralization tank 5a are circulated.

As shown in FIG. 2 (white arrows), the first circulation flow path 40a allows water sent from the treatment tank 13 by the water pump 14 to pass through the electrolytic tank 11, the second water softening tank 4b, and the first water softening tank. 4a and returns to the processing bath 13 for circulation. More specifically, the first circulation flow path 40a allows the water sent from the treatment tank 13 by the water supply pump 14 to flow through the water supply flow path 50, the electrolytic tank 11, the first supply flow path 41, the on-off valve 63, the second soft water The water softening tank 4b, the first bypass channel 43, the on-off valve 65, the first water softening tank 4a, the first recovery channel 45, the on-off valve 61, and the treatment tank 13 are circulated in this order.

As shown in FIG. 2 (black arrows), the second circulation flow path 40b allows water sent from the treatment tank 13 by the water pump 14 to pass through the electrolytic tank 11, the second neutralization tank 5b, and the first neutralization tank. 5a and returns to the processing tank 13 for circulation. More specifically, the second circulation flow path 40b allows water sent from the treatment tank 13 by the water supply pump 14 to flow through the water supply flow path 50, the electrolytic cell 11, the second supply flow path 42, the on-off valve 64, the second medium The sum tank 5b, the second bypass flow path 44, the on-off valve 66, the first neutralization tank 5a, the second recovery flow path 46, the on-off valve 62, and the treatment tank 13 are circulated in this order.

Here, the state of each channel for circulating water in the circulation channel 40 will be described.

An on-off valve 54 is installed in the channel 33 downstream of the first supply channel 41 and upstream of the second bypass channel 44 . By closing the on-off valve 54 and opening the on-off valve 63, the first supply flow path 41 is connected to the downstream side of the second water softening tank 4b. As a result, the acidic electrolyzed water from the electrolytic bath 11 can be supplied to the second water softening bath 4b.

An on-off valve 52 is installed in the channel 31 downstream of the first bypass channel 43 and upstream of the second recovery channel 46 . In addition, an on-off valve 53 is installed on the downstream side of the second bypass flow path 44 and the upstream side of the first bypass flow path 43 in the flow path 32 . Then, by closing the on-off valve 52 and the on-off valve 53 and opening the on-off valve 65, the first bypass flow flows upstream of the second water softening tank 4b and downstream of the first water softening tank 4a. The path 43 will be in a state of communication and connection. As a result, the acidic electrolyzed water that has flowed through the second water softening tank 4b can be supplied to the first water softening tank 4a.

In addition, an on-off valve 51 is installed in the channel 30 downstream of the inlet 2 and upstream of the first recovery channel 45 . By closing the on-off valve 51 and the on-off valve 52 and opening the on-off valve 61, the first recovery passage 45 is connected to the upstream side of the first water softening tank 4a. As a result, in the water softening device 1 , the water (acidic electrolyzed water containing hardness components) that has flowed through the first water softening tank 4 a and the second water softening tank 4 b can be recovered to the treatment tank 13 .

Further, by closing the on-off valve 52 and opening the on-off valve 62, the second recovery passage 46 is connected to the upstream side of the first neutralization tank 5a. As a result, the water (alkaline electrolyzed water containing anions) that has flowed through the first neutralization tank 5 a and the second neutralization tank 5 b can be recovered into the treatment tank 13 .

In addition, by closing the on-off valve 52, the on-off valve 53, and the on-off valve 54 and opening the on-off valve 66, The second bypass channel 44 is in a state of being connected. As a result, the alkaline electrolyzed water that has flowed through the second neutralization tank 5b can be supplied to the first neutralization tank 5a.

By closing the on-off valves 54 and 55 and opening the on-off valve 64, the second supply flow path 42 is connected to the downstream side of the second neutralization tank 5b. As a result, in the water softening device 1, the alkaline electrolyzed water from the electrolytic tank 11 can be supplied to the second neutralizing tank 5b.

In addition, an on-off valve 71 is installed in the water supply channel 50 on the downstream side of the treatment tank 13 (position between the treatment tank 13 and the water supply pump 14). Water can be stored in the processing bath 13 by closing the on-off valve 71 . On the other hand, water can be supplied to the water supply channel 50 by opening the on-off valve 71 .

Further, by closing the on-off valve 51 and the on-off valve 55, water can be supplied to the circulation channel 40, while by opening the on-off valve 51 and the on-off valve 55, water can be supplied to the circulation channel 40. can stop the supply of

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

Next, the operation of the water softening device 1 will be described.

<Water softening treatment, regeneration treatment, and wastewater treatment>
Next, with reference to FIG. 3, the water softening treatment, regeneration treatment, and wastewater treatment of the water softening device 1 starting from the regeneration treatment will be described. FIG. 3 is a diagram showing the state of the water softening device 1 during operation.

In the water softening process, the regeneration process, and the wastewater treatment, as shown in FIG. The on-off valve 71, the on-off valve 72, the electrode 12 of the electrolytic cell 11, and the water pump 14 are switched and controlled to be in the respective flow states.

Here, "ON" in FIG. 3 indicates a state in which the raw water detection unit 3 and the soft water detection unit 6 are energized, a state in which the corresponding on-off valve is "open", a state in which the electrode 12 is energized, and water supply. Each shows a state in which the pump 14 is operating. Blanks indicate a state in which the raw water detection unit 3 and the soft water detection unit 6 are not energized, a state in which the corresponding on-off valve is "closed", a state in which the electrode 12 is not energized, and a state in which the water pump 14 is stopped. show.

<< Regeneration processing >>
First, the operation during regeneration processing by the regeneration device 8 of the water softening device 1 will be described in order with reference to the columns "during injection of water" and "during regeneration" in FIG.

In the water softening device 1, the water softening tank 4 filled with the weakly acidic cation exchange resin 9 loses or loses its cation exchange capacity with continued use. That is, after all hydrogen ions, which are functional groups of the cation exchange resin, are exchanged with calcium ions or magnesium ions, which are hardness components, ion exchange becomes impossible. In such a state, hardness components come to be contained in the treated water. Therefore, in the water softening device 1 , it is necessary to regenerate the water softening tank 4 and the neutralization tank 5 by the regenerating device 8 .

Therefore, in the water softening device 1, once in a predetermined period (for example, 24 hours), the control unit 20 specifies a time zone in which the regeneration process is possible, and executes the regeneration process.

First, as shown in FIG. 3, the on-off valve 51 and the on-off valve 61 are opened during water injection. As a result, the water softener 1 introduces the raw water from the inflow port 2 into the treatment tank 13 via the first recovery channel 45 by the pressure of the city water. At this time, the on-off valves 52 to 55, the on-off valves 62 to 66, the on-off valves 71 and 72 are closed. By storing a predetermined amount of water corresponding to the capacity of the water softening device 1 in the processing tank 13, the regenerating device 8 can secure the amount of water for regenerating.

Next, during regeneration, when the on-off valves 51 to 55 and 72 are closed and the on-off valves 61 to 66 and 71 are opened, as shown in FIG. A channel 40a and a second circulation channel 40b are formed respectively.

When the electrodes 12 of the electrolytic bath 11 and the water pump 14 are operated, the water stored in the treatment bath 13 circulates through the first circulation channel 40a and the second circulation channel 40b.

At this time, the acidic electrolyzed water generated in the electrolytic cell 11 flows through the first supply channel 41, is sent into the second water softening tank 4b, and flows through the second weakly acidic cation exchange resin 9b inside. Then, the acidic electrolyzed water that has flowed through the second water softening tank 4b flows through the first bypass channel 43, is sent into the first water softening tank 4a, and flows through the first weakly acidic cation exchange resin 9a inside. do. That is, by passing acidic electrolyzed water through the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b, the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin The cations (hardness components) adsorbed to 9b undergo an ion exchange reaction with hydrogen ions contained in the acidic electrolyzed water. As a result, the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b are regenerated. After that, the acidic electrolyzed water that has flowed through the first weakly acidic cation exchange resin 9 a contains cations and flows into the first recovery channel 45 . That is, the acidic electrolyzed water containing cations that has passed through the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b is processed through the first bypass channel 43 and the first recovery channel 45. It is collected in tank 13 .

In this way, the first circulation flow path 40a is positioned most downstream from the inlet of the raw water for the acidic electrolyzed water. First soft water having a first weakly acidic cation exchange resin 9a that is circulated from the downstream side of the tank 4b and is located upstream and adsorbs more hardness components than the second weakly acidic cation exchange resin 9b. It is caused to flow into the downstream side of the gasification tank 4a. That is, the first circulation flow path 40a circulates the acidic electrolyzed water sent from the electrolytic tank 11 to the second water softening tank 4b, and then sends it to the first water softening tank 4a through the first bypass flow path 43. Then, the water is circulated through the first water softening tank 4 a , collected in the treatment tank 13 , and then flowed into the electrolytic tank 11 . Also, the first circulation flow path 40a circulates the acidic electrolyzed water sent from the electrolytic tank 11 from the downstream side of the first water softening tank 4a and the second water softening tank 4b to the first water softening tank 4a and the second water softening tank 4b. It is introduced into the water softening tank 4b and discharged from the upstream side of each water softening tank where the amount of adsorbed hardness components is greater than that on the downstream side.

On the other hand, the alkaline electrolyzed water produced in the electrolytic bath 11 is fed through the second supply channel 42 into the second neutralization bath 5b and flows through the second weakly basic anion exchange resin 10b inside. Then, the alkaline electrolyzed water that has flowed through the second neutralization tank 5b flows through the second bypass flow path 44, is sent into the first neutralization tank 5a, and displaces the first weakly basic anion exchange resin 10a inside. circulate. That is, by passing alkaline electrolyzed water through the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b, the first weakly basic anion exchange resin 10a and the second weakly basic The anions adsorbed on the anion exchange resin 10b undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water. This regenerates the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b. After that, the alkaline electrolyzed water that has flowed through the second weakly basic anion exchange resin 10 b contains anions and flows into the second recovery channel 46 . That is, the alkaline electrolyzed water containing anions that has flowed through the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b passes through the second bypass channel 44 and the second recovery channel 46. It is collected in the processing tank 13 by the pressure.

Then, in the treatment tank 13, acidic electrolyzed water containing cations recovered from the first water softening tank 4a and the second water softening tank 4b and recovered from the first neutralization tank 5a and the second neutralization tank 5b It is neutralized by being mixed with alkaline electrolyzed water containing anions.

At this time, by mixing acidic electrolyzed water containing cations (hardness components) and alkaline electrolyzed water containing anions, the hardness components react with the hydroxide ions contained in the alkaline electrolyzed water, and deposits are formed. occur. For example, when the hardness component in the acidic electrolyzed water is calcium ions, the alkaline electrolyzed water produces calcium hydroxide, or combines with carbonate ions normally present in water to produce calcium carbonate.

After that, the treated water treated in the treatment tank 13 has reaction products removed when it flows through the filtration unit 15 , and is again passed through the electrolytic tank 11 through the water supply channel 50 . Then, the water that has been passed through is electrolyzed again in the electrolytic bath 11 . The electrolyzed water (acidic electrolyzed water, alkaline electrolyzed water) electrolyzed again in the electrolytic cell 11 is used for regeneration of the weakly acidic cation exchange resin 9 and weakly basic anion exchange resin 10, respectively.

Then, in the water softening device 1, the operations of the electrodes 12 and the water pump 14 are stopped when the regeneration process is completed. Also, by opening the on-off valve 72, the process proceeds to wastewater treatment. It should be noted that the end of the regeneration process may be set for a certain period of time from the start of the regeneration process (when the electrode 12 starts operating).

<< Wastewater treatment >>
In the water softening device 1, when the regeneration process is completed, the process shifts to wastewater treatment. Here, the drainage treatment is a treatment for draining the acidic electrolyzed water and the alkaline electrolyzed water remaining in the circulation flow path 40 .

Next, the operation of the water softening device 1 during wastewater treatment will be described with reference to the "drainage" column in FIG.

In the water softening device 1, as shown in FIG. 3, the on-off valves 51 to 55 are closed, and the on-off valves 61 to 66, the on-off valve 71, and the on-off valve 72 are closed in the wastewater treatment (at the time of drainage). Open.

As a result, the acidic electrolyzed water remaining in the first circulation channel 40 a and the alkaline electrolyzed water remaining in the second circulation channel 40 b can flow into the treatment tank 13 .

Next, when the on-off valve 72 is opened, the action of the air vent valve 16 allows the electrolyzed water in the treatment tank 13 to be discharged outside the apparatus.

By performing waste water treatment, when the water softening treatment is restarted, the acidic electrolyzed water and alkaline electrolyzed water remaining in the circulation flow path 40 are mixed with the raw water flowing in from the inlet 2 and discharged from the water intake 7. can be prevented.

In the water softening device 1, when the waste water treatment is completed, the on-off valves 61 to 66, the on-off valve 71, and the on-off valve 72 are closed, and the on-off valves 51 to 55 are opened to start the water softening treatment. Transition. It should be noted that the end of the wastewater treatment may be set when a certain period of time has elapsed from the start of the wastewater treatment.

<<Water softening treatment>>
The water softening device 1 shifts to the water softening process when the waste water treatment is completed.

Next, the operation of the water softening device 1 during the water softening process will be described with reference to the "water softening" column in FIG.

In the water softening device 1, as shown in FIG. 3, in the water softening process (during water softening), the on-off valve 55 provided at the water intake 7 is opened while the on-off valves 51 to 54 are open. As a result, city water (raw water containing hardness components) from the outside flows through the water softening tank 4 and the neutralization tank 5, so that the water softening device 1 softens water (neutral soft water) from the water intake 7. can be taken out. At this time, the on-off valves 61 to 66, the on-off valve 71, and the on-off valve 72 are all closed. Moreover, the operation of the electrode 12 of the electrolytic cell 11 and the water pump 14 is also stopped.

Specifically, as shown in FIG. 1, in the water softening process, raw water is supplied from the inflow port 2 through the channel 30 to the first water softening tank 4a. The raw water supplied to the first water softening tank 4a then flows through the first weakly acidic cation exchange resin 9a provided in the first water softening tank 4a. At this time, cations, which are hardness components in the raw water, are adsorbed by the action of the first weakly acidic cation exchange resin 9a, and hydrogen ions are released (ion exchange is performed). Then, the raw water is softened by removing the cations from the raw water. However, the water softened by the first weakly acidic cation exchange resin 9a contains many hydrogen ions that have flowed out after being exchanged with hardness components, so that the water is acidified and has a low pH. Since water softening does not progress easily when the pH is lowered, the water that has flowed through the first water softening tank 4a is passed through the first neutralizing tank 5a for neutralization.
The softened water further flows through the channel 31 and flows into the first neutralization tank 5a. In the first neutralization tank 5a, hydrogen ions contained in the softened water are adsorbed by the action of the first weakly basic anion exchange resin 10a. That is, since hydrogen ions are removed from the water softened by the first water softening tank 4a, the lowered pH is raised and neutralized.
Therefore, compared with the case where the water softened in the first water softening tank 4a is directly softened in the second water softening tank 4b, the water softening treatment in the second water softening tank 4b proceeds more easily. The water neutralized by the first neutralization tank 5a further flows through the channel 32 and flows into the second water softening tank 4b.

In the second water softening tank 4b, the neutralized water is passed through the channel 32 and passes through the second weakly acidic cation exchange resin 9b filled inside. As a result, in the second water softening tank 4b, cations, which are hardness components, are adsorbed by the action of the second weakly acidic cation exchange resin 9b, and hydrogen ions are released. That is, in the second water softening tank 4b, the hardness components that could not be removed in the first water softening tank 4a are exchanged with the hydrogen ions of the second weakly acidic cation exchange resin 9b to soften the water. However, since the water softened by the second weakly acidic cation exchange resin 9b contains hydrogen ions that have flowed out after being exchanged with hardness components, it is acidic water. Soft water containing hydrogen ions flows through the channel 33 and flows into the second neutralization tank 5b. In the second neutralization tank 5b, hydrogen ions contained in the inflowing soft water are adsorbed by the action of the second weakly basic anion exchange resin 10b. That is, since the hydrogen ions are removed from the soft water, the lowered pH is increased, and the softened neutral water that can be used as domestic water is obtained. In other words, in the second neutralization tank 5b, acid water that has flowed out of the second water softening tank 4b and contains hydrogen ions released from the second weakly acidic cation exchange resin 9b is neutralized. . The neutralized soft water can flow through the channel 34 and be taken out from the water intake 7 .

Then, in the water softening device 1, the regeneration process is executed when the time period specified by the control unit 20 has come or when the water softening process has exceeded a certain period of time.

<<Calculation of hardness of soft water>>
In the water softening device 1 , the raw water detector 3 detects the electrical conductivity of the raw water flowing through the channel 30 , and the soft water detector 6 detects the electrical conductivity of the soft water flowing through the channel 34 . Further, in the acquisition unit 17, the electrical conductivity of the raw water output from the raw water detection unit 3 is subjected to a certain correction (such as multiplication of the electrical conductivity of the raw water by a predetermined value), and Acquire the electrical conductivity (first electrical conductivity) corresponding to the ion and output the first electrical conductivity. Using the output first electrical conductivity, the electrical conductivity of soft water is calibrated in the calibration unit 18 (subtracting the first electrical conductivity value from the electrical conductivity value of soft water), and the second electrical conductivity output as Using the output second electrical conductivity, the calculator 19 calculates the hardness of the soft water (multiplying the second electrical conductivity by a predetermined value, etc.) and outputs the hardness of the soft water as a numerical value.

As described above, the water softening device 1 repeatedly performs the water softening process, the regeneration process, and the waste water process.

As described above, according to the water softening device 1 according to Embodiment 1, the following effects can be obtained.

(1) The water softening device 1 includes a water softening tank 4, a neutralization tank 5, a raw water detection unit 3, a soft water detection unit 6, an acquisition unit 17, a calibration unit 18, a calculation unit 19, and a display unit. 21. The water softening tank 4 softens raw water containing hardness components with a weakly acidic cation exchange resin 9 . Neutralization tank 5 neutralizes the pH of the softened water that has passed through water softening tank 4 with weakly basic anion exchange resin 10 . The raw water detector 3 detects electrical conductivity of raw water. Soft water detector 6 detects the electric conductivity of the softened water that has passed through softening tank 4 and neutralizing tank 5 . The acquiring unit 17 acquires electrical conductivity (first electrical conductivity) corresponding to ions other than hardness components in raw water. The calibration unit 18 calibrates the electrical conductivity obtained by the soft water detection unit 6 based on the electrical conductivity corresponding to the ions other than the hardness component in the raw water, which is acquired by the acquisition unit 17, to obtain the second electrical conductivity to output The calculator 19 calculates the hardness of soft water based on the second electrical conductivity output from the calibrator 18 . The display unit 21 notifies the hardness of the soft water calculated by the calculation unit 19 . The water softener 1 is configured such that raw water flows through the raw water detector 3, the water softening tank 4, the neutralization tank 5, and the softened water detector 6 in this order.

According to such a configuration, the electrical conductivity of the raw water is acquired in the raw water detection unit 3, and the electrical conductivity of the raw water is corrected by a certain correction (such as multiplication by a predetermined value) in the acquisition unit 17, so that ions other than the hardness component The electrical conductivity (first electrical conductivity) corresponding to the component is acquired, and the electrical conductivity of the soft water detected by the soft water detection unit 6 is detected by the calibration unit 18 based on the electrical conductivity corresponding to the ion component other than the hardness component. An electric conductivity (second electric conductivity) obtained by calibrating the conductivity is obtained, and the hardness component in the soft water can be calculated from the second electric conductivity in the calculation unit 19 . Therefore, even when hard water containing a mixture of hardness components and other ionic components is circulated, the hardness components in the soft water can be calculated from the electrical conductivity of the hard water and the soft water obtained by circulating the hard water. In addition, since the display unit 21 is provided, the information on the hardness components in the soft water output from the calculation unit 19 is displayed on the display unit 21 . A user of the water softening device 1 can visually know the hardness of the soft water taken out from the water softening device 1 .

(2) The water softening device 1 includes a water softening tank 4 and a neutralization tank 5 . The water softening tank 4 softens raw water containing hardness components with a weakly acidic cation exchange resin 9 . Neutralization tank 5 neutralizes the pH of the softened water that has passed through water softening tank 4 with weakly basic anion exchange resin 10 . The water softening tank 4 has a first water softening tank 4a and a second water softening tank 4b. The neutralization tank 5 has a first neutralization tank 5a and a second neutralization tank 5b. The water softening device 1 is configured so that raw water flows through the first water softening tank 4a, the first neutralizing tank 5a, the second water softening tank 4b, and the second neutralizing tank 5b in this order.

According to such a configuration, the raw water containing hardness components flows out of the first water softening tank 4a before the pH of the raw water decreases due to the water softening treatment in the first water softening tank 4a, and the first neutralization tank It is neutralized in 5a and softened in the second water softening tank 4b. Therefore, it is possible to suppress the decrease and acidification of the pH of the water circulating in the water softening tank 4, so that the hardness component is exchanged with the hydrogen ion retained by the second weakly acidic cation exchange resin 9b of the second water softening tank 4b. becomes more likely to occur. Therefore, the water softening device 1 can improve the water softening performance as compared with the case where the water softening tank 4 and the neutralizing tank 5 are not divided.

(3) In the water softening device 1, acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 9 in the water softening tank 4 and alkaline water for regenerating the weakly basic anion exchange resin 10 in the neutralizing tank 5 It further comprises an electrolytic bath 11 for producing electrolyzed water, and a treatment bath 13 for mixing the acidic electrolyzed water that has passed through the water softening bath 4 and the alkaline electrolyzed water that has passed through the neutralizing bath 5 and supplying the mixture to the electrolytic bath 11. I made it According to such a configuration, it is possible to regenerate the weakly acidic cation exchange resin 9 with the acidic electrolyzed water generated in the electrolytic cell 11, and it is possible to regenerate the weakly basic anion exchange resin 10 with the alkaline electrolyzed water. becomes. Therefore, the maintenance frequency of the water softener 1 can be reduced, and the water softener 1 can be used for a long period of time.

(Embodiment 2)
The water softening device 1a according to Embodiment 2 of the present invention does not include the raw water detection unit 3, and the electrical conductivity of the softened water in the first period until the electrical conductivity reaches the first predetermined value is the first A point of providing a determination unit 22 for determining a second period after reaching a predetermined value, a point of providing a storage unit 23 for storing the electrical conductivity of soft water at the beginning of the second period as a reference electrical conductivity, The calculation unit 19a differs from the first embodiment in that the hardness component information is calculated based on the reference electrical conductivity and the electrical conductivity of soft water. Other configurations of the water softening device 1a are the same as those of the water softening device 1 according to the first embodiment. In the following, repetitive explanations of the contents already explained in the first embodiment will be omitted as appropriate, and differences from the first embodiment will be mainly explained.

A water softening device 1a according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a conceptual diagram showing a water softening device 1a according to Embodiment 2 of the present invention. In addition, FIG. 4 conceptually shows each element of the water softening device 1a.

<Overall composition>
The water softening device 1a is a device that generates neutral soft water from raw water supplied from the outside and containing hardness components.

Specifically, as shown in FIG. 3, the water softening device 1a includes a water softening tank 4 (first water softening tank 4a and second water softening tank 4b), a neutralizing tank 5 (first neutralizing tank 5a and a second neutralization tank 5b), a soft water detector 6a for detecting electrical conductivity of the treated soft water, an intake port 7 for the treated soft water, and a regeneration device 8. The regeneration device 8 includes an electrolytic bath 11 , a treatment bath 13 and a water pump 14 . In addition, the water softening device 1 includes a plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, on-off valves 71 and 72), a calculation unit 19a, a control unit 20, and a display unit. 21 , a determination unit 22 and a storage unit 23 .

<Soft water detector>
The soft water detection unit 6a is provided in the flow path 34 and detects the electrical conductivity of neutral soft water (electrical conductivity of soft water) flowing out from the second neutralization tank 5b. The soft water detection unit 6 is connected to the control unit 20, the determination unit 22, and the storage unit 23, which will be described later, so as to be able to communicate wirelessly or by wire. and used as an input signal for the storage unit 23 . As the soft water detector 6a, a general-purpose detector can be used as long as it measures the electrical conductivity of liquid.

<Determination part>
The determination unit 22 is connected to the control unit 20, which will be described later, and includes a storage unit 23, which will be described later. The determination unit 22 compares the electric conductivity of the soft water detected by the soft water detection unit 6 with the reference electric conductivity described later, and determines the period until the electric conductivity of the soft water reaches the reference electric conductivity as the first term, the reference electric conductivity. The period after reaching the electric conductivity is determined as the second period. The determination result is used when calculating the hardness component in the soft water in the calculator 19a.

A specific determination method for the first period and the second period will be described with reference to FIG. FIG. 5 is a diagram showing changes in electrical conductivity during water softening by the water softening apparatus according to Embodiment 2 of the present invention.

Specifically, taking the water softening process of the water softening device 1a after the regeneration process as an example, as shown in FIG. It is divided into B and section C. Section A is a section in which the electrical conductivity of soft water is lower than the reference electrical conductivity. Section B is a section in which the electrical conductivity of soft water is approximately the same as the reference electrical conductivity (for example, about ±5% from the reference electrical conductivity). Section C is a section in which the electrical conductivity of soft water exceeds the reference electrical conductivity. The determination unit 22 determines the portion corresponding to the section A as the first period, and the portion corresponding to the sections B and C as the second period. The reason why the electrical conductivity of softened water behaves as shown in FIG. In this case, it is affected by the fact that the susceptibility to the ion exchange reaction with the weakly acidic cation exchange resin 9 is different between calcium ions and magnesium ions, which are hardness components, and monovalent cations such as sodium ions. . Specifically, the ion exchange reaction with the weakly acidic cation exchange resin 9 occurs more easily with calcium ions and magnesium ions, which are hardness components, than with monovalent cations. Hereinafter, the monovalent cation will be described using sodium ion as an example. In section A, almost all of the hardness components are ion-exchanged, and some of the sodium ions are ion-exchanged. However, sodium ions become more difficult to be ion-exchanged as the total flow rate of raw water increases. Therefore, in section A, an increase in the electrical conductivity of soft water due to the electrical conductivity of sodium ions is observed. In section B, substantially all of the hardness components are ion-exchanged, while substantially all of the sodium ions are not ion-exchanged and are contained in the water. In section B, since there is no significant change in the amount and composition of the ionic components in the soft water, the electrical conductivity of the soft water continues to maintain a similar value. In section C, ion exchange between the hydrogen ions of the terminal functional groups of the weakly acidic cation exchange resin 9 and the hardness component progresses, and as a result, the ion exchange reaction itself becomes difficult to occur gradually, and the concentration of the hardness component in the water increases. An increase in the electrical conductivity of soft water due to the increase occurs.

That is, section A is a section in which the electrical conductivity of soft water increases due to ions other than hardness components such as sodium ions, and section C is a section in which the electrical conductivity of soft water increases due to ions of hardness components. Due to the difference in the ease with which the ion-exchange reaction occurs, basically, the concentration of the hardness component does not increase before the sodium ions are no longer ion-exchanged. Therefore, in section A and section B, the concentration of hardness components in soft water can be regarded as zero.

<<storage unit>>
The storage unit 23 stores the electric conductivity value of the soft water corresponding to the section B in FIG. 5 as the reference electric conductivity. The stored reference electrical conductivity is output to the determination unit 22 and used to determine the intervals A, B and C, and the first and second periods. Regarding the timing of the electrical conductivity to be used as the reference electrical conductivity, the total flow rate of raw water and the amount of change in the electrical conductivity of soft water with respect to the total flow rate of raw water (slope in the graph) are taken into consideration. The electrical conductivity of soft water when the amount of change in the electrical conductivity of the soft water with respect to the total flow of raw water is less than a certain value (e.g., 0.1 μS/cm L or less), or when the variation in the electrical conductivity is the smallest. is preferably taken as the reference electrical conductivity. In addition, by updating and storing the reference electric conductivity at regular intervals (for example, one month), it is possible to set the reference electric conductivity corresponding to the change even when the ionic component composition of the raw water changes. can.

The storage unit 23 may be provided inside the determination unit 22 or may be provided outside the determination unit 22 as long as it can be connected to the determination unit 22 .

<Calculation part>
The calculation unit 19a is connected to the control unit 20 to be described later, and based on the electrical conductivity of the soft water detected by the soft water detection unit 6 and the reference electrical conductivity output from the determination unit 22 and the storage unit 23, Calculate and output the hardness component. The calculation method differs depending on whether the determination by the determination unit 22 is the first period or the second period. In the case of the first period, the hardness component in the soft water is calculated as 0 regardless of the electrical conductivity of the soft water. In the case of the second period, for example, a method of subtracting the reference electrical conductivity from the electrical conductivity of the soft water and multiplying the calculated value by a predetermined value can be used. The predetermined value here is a constant of proportionality between "the difference between the electrical conductivity of the soft water and the reference electrical conductivity" and the "hardness component in the soft water". Generally, the electrical conductivity of water is proportional to the concentration of ionic components in water, and the higher the concentration of ionic components in water, the greater the electrical conductivity. The constants of proportionality for ion concentration and electrical conductivity differ depending on the ion species. In the "difference between the electrical conductivity of soft water and the standard electrical conductivity", in addition to the electrical conductivity due to the hardness component, the electrical conductivity due to anions such as chloride ions, nitrate ions, and sulfate ions is also included. By adjusting the setting of the predetermined value in consideration of the anion composition corresponding to the country or region where the water softening device 1a is used, the hardness component in the soft water can be calculated more accurately.

<Control part>
The control unit 20 controls a water softening process for softening raw water containing hardness components. In addition, the control unit 20 controls regeneration of the weakly acidic cation exchange resin 9 in the water softening tank 4 and the weakly basic anion exchange resin 10 in the neutralization tank 5 . Further, the control unit 20 controls switching of the water softening device 1 among the water softening process, the regeneration process, and the waste water process. At this time, the control unit 20 controls the operation of the electrode 12, the water pump 14, the on-off valves 51 to 55, the on-off valves 61 to 66, the on-off valve 71, and the on-off valve 72, and softens the water and regenerates the water. Processing and wastewater treatment are switched, and each treatment is executed.

In addition, the control unit 20 is connected to the determination unit 22, the storage unit 23, the calculation unit 19a, and the display unit 21, respectively, and controls the input/output of the electrical conductivity of soft water, the reference electrical conductivity, and the hardness component in soft water, respectively. .

<Calculation of hardness of soft water>
In the water softening device 1a, the determination unit 22 compares the electrical conductivity of the soft water output from the soft water detection unit 6a with the reference electrical conductivity, and determines the period until the electrical conductivity of the soft water reaches the reference electrical conductivity. is determined as the first period, and the period after reaching the reference electrical conductivity is determined as the second period. As the reference electrical conductivity, the value of the electrical conductivity of soft water corresponding to section B in FIG. Then, the calculation unit 19a calculates and outputs the hardness component of the soft water based on the electrical conductivity of the soft water detected by the soft water detection unit 6a and the reference electrical conductivity output from the determination unit 22 and the storage unit 23. . The calculation differs depending on whether the judgment by the judging unit 22 is the first period or the second period. , subtracting the reference electrical conductivity from the electrical conductivity of the soft water, and multiplying the value obtained by the subtraction by a predetermined value.

As described above, according to the water softening device 1a according to the second embodiment, the following effects can be obtained.

The water softening device 1 a includes a water softening tank 4 , a neutralizing tank 5 , a water softening detection section 6 a, a determination section 22 , a storage section 23 , a calculation section 19 a and a display section 21 . The water softening tank 4 softens raw water containing hardness components with a weakly acidic cation exchange resin 9 . Neutralization tank 5 neutralizes the pH of the softened water that has passed through water softening tank 4 with weakly basic anion exchange resin 10 . The softened water detector 6 a detects the electric conductivity of the softened water that has passed through the water softening tank 4 and the neutralizing tank 5 . The determination unit 22 compares the electrical conductivity of the soft water detected by the soft water detection unit 6a with the reference electrical conductivity, and determines the period until the electrical conductivity of the soft water reaches the reference electrical conductivity as the first term, the reference electrical conductivity The period after reaching the degree is determined as the second period. The storage unit 23 stores the electrical conductivity of the soft water when the amount of change in the electrical conductivity of the soft water with respect to the flow rate of the raw water is small as the reference electrical conductivity.

The calculation unit 19a calculates and outputs the hardness component in the soft water based on the electrical conductivity of the soft water output by the soft water detection unit 6a and the reference electrical conductivity output from the determination unit 22 and the storage unit 23. . The display unit 21 notifies the hardness of the soft water calculated by the calculation unit 19a. The water softening device 1a is configured such that raw water flows through the water softening tank 4, the neutralization tank 5, and the soft water detector 6a in this order.

According to such a configuration, the electrical conductivity of the raw water is acquired in the raw water detection unit 3, and the electrical conductivity of the raw water is corrected by a certain correction (such as multiplication by a predetermined value) in the acquisition unit 17, so that ions other than the hardness component The electrical conductivity (first electrical conductivity) corresponding to the component is acquired, and the electrical conductivity of the soft water detected by the soft water detection unit 6a is detected by the calibration unit 18 based on the electrical conductivity corresponding to the ion component other than the hardness component. An electrical conductivity (second electrical conductivity) obtained by calibrating the conductivity is acquired, and the hardness component in the soft water can be calculated from the second electrical conductivity in the calculation unit 19a. Therefore, unlike Embodiment 1, even if the raw water detection unit and the acquisition unit are not provided, the first electrical conductivity in Embodiment 1 is predicted from the change behavior of the electrical conductivity of soft water, and is used as the reference electrical conductivity. can be set. As in the first embodiment, even when hard water containing a mixture of hardness components and other ionic components is circulated, the hardness components in the soft water are calculated from the electrical conductivity of the hard water and the soft water obtained by circulating the hard water. It becomes possible to

(Embodiment 3)
The water softening device 1b according to Embodiment 3 of the present invention is based on the difference between the electrical conductivity of the soft water and the third electrical conductivity in the first period until the electrical conductivity of the soft water reaches the reference electrical conductivity. The point of calculating the hardness component, and the point of having a regeneration device 8b that distributes the reclaimed water on the acid side and the alkaline side without mixing by dividing the water intake port after the electrolytic cell 11b into two places, one for the acid side and the other for the alkali side. is different from the first and second embodiments. Other configurations of the water softening device 1b are the same as those of the water softening device 1a according to the second embodiment. In the following, repetitive explanations of the contents already explained in the second embodiment will be omitted as appropriate, and differences from the second embodiment will be mainly explained.

A water softening device 1b according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 6 is a conceptual diagram showing a water softening device 1b according to Embodiment 3 of the present invention. Note that FIG. 6 conceptually shows each element of the water softening device 1b.

<Overall composition>
The water softening device 1b is a device that generates neutral soft water from raw water supplied from the outside and containing hardness components.

Specifically, as shown in FIG. 6, the water softening device 1b includes a water softening tank 4 (first water softening tank 4a and second water softening tank 4b), a neutralizing tank 5 (first neutralizing tank 5a and a second neutralization tank 5b), a soft water detector 6a for detecting electrical conductivity of the treated soft water, an intake port 7 for the treated soft water, and a regeneration device 8b. The water softening device 1b also includes a plurality of on-off valves (on-off valves 51 to 55, on-off valves 61 to 66, and on-off valves 73 to 76), a control unit 20b, and a display unit 21. consists of

<Playback device>
The regeneration device 8 b is a device that regenerates the weakly acidic cation exchange resin 9 in the water softening tank 4 and regenerates the weakly basic anion exchange resin 10 in the neutralization tank 5 . Specifically, the regeneration device 8b includes an electrolytic cell 11b, an acidic electrolyzed water storage tank 26, an alkaline electrolyzed water storage tank 28, an acidic electrolyzed water circulation pump 24, an alkaline electrolyzed water circulation pump 25, and a filtration unit 15. composed of Then, the regeneration device 8b provides a first supply channel 41, a first recovery channel 45, a first recovery channel 45, and a A second supply channel 42 and a second recovery channel 46 are connected to each other. Moreover, the channel 31 and the channel 32 are connected by the first bypass channel 43 . Moreover, the channel 32 and the channel 33 are connected by the second bypass channel 44 . Also, the first supply channel 41 and the first recovery channel 45 are connected by the first water supply channel 47 . Also, the second supply channel 42 and the second recovery channel 46 are connected by the second water supply channel 48 . Each channel constitutes a circulation channel 40 (a first circulation channel 40c and a second circulation channel 40d), which will be described later.

Here, the first supply channel 41 is a channel for supplying acidic electrolyzed water from a first discharge port 36 of the electrolytic bath 11b, which will be described later, to the second water softening bath 4b.

The first bypass channel 43 is a channel for bypassing the first neutralization tank 5a and supplying the acidic electrolyzed water that has flowed through the second water softening tank 4b to the first water softening tank 4a.

The first recovery channel 45 is a channel for recovering the acidic electrolyzed water containing the hardness component that has passed through the first water softening tank 4 a into the acidic electrolyzed water storage tank 26 .

The first water supply channel 47 is a channel for supplying the acidic electrolyzed water collected by the acidic electrolyzed water storage tank 26 to the first water intake port 35 of the electrolytic cell 11b to be described later by the acidic electrolyzed water circulation pump 24 .

The second supply channel 42 is a channel for supplying alkaline electrolyzed water from a second discharge port 38 of the electrolytic bath 11b, which will be described later, to the second neutralization bath 5b.

The second bypass flow path 44 is a flow path that bypasses the second water softening tank 4b and supplies the alkaline electrolyzed water that has flowed through the second neutralization tank 5b to the first neutralization tank 5a.

The second recovery channel 46 is a channel for recovering the alkaline electrolyzed water that has passed through the first neutralization tank 5 a into the alkaline electrolyzed water storage tank 28 .

The second water supply channel 48 is a channel for supplying the alkaline electrolyzed water collected by the alkaline electrolyzed water storage tank 28 to the second water intake port 37 of the electrolytic cell 11b to be described later by the alkaline electrolyzed water circulation pump 25 .

<<Electrolyzer>>
The electrolytic cell 11b produces acidic electrolyzed water for regenerating the weakly acidic cation exchange resin 9 and alkaline electrolyzed water for regenerating the weakly basic anion exchange resin 10 by electrolysis of water. The electrolytic cell 11b includes an electrode 12a, an electrode 12b, a diaphragm 80, an anode chamber 81, and a cathode chamber 82.

Here, with reference to FIG. 6, a case will be described in which current is applied so that the potential of the electrode 12a is higher than that of the electrode 12b. The electrolytic cell 11b is separated into an anode chamber 81 and a cathode chamber 82 by a diaphragm 80 provided inside.

The diaphragm 80 suppresses mixing of the acidic electrolyzed water generated in the anode chamber 81 and the alkaline electrolyzed water generated in the cathode chamber 82 during the regeneration process. Thereby, consumption of hydrogen ions in the acidic electrolyzed water and hydroxide ions in the alkaline electrolyzed water by the neutralization reaction can be suppressed. Therefore, the diaphragm 80 can suppress a decrease in regeneration efficiency of the weakly acidic cation exchange resin 9 and the weakly basic anion exchange resin 10 . As the diaphragm 80, for example, a fluorine-based porous film can be used. As the porous membrane used for the diaphragm 80, in addition to the fluorine-based porous membrane, a generally used porous membrane such as a hydrocarbon-based porous membrane may be used. Therefore, the water softening device 1b uses a fluorine-based porous membrane.

The anode chamber 81 is a portion where acidic electrolyzed water is generated during electrolysis of water. The anode chamber 81 has an electrode 12 a , a first water intake port 35 and a first discharge port 36 .

As an anode, the electrode 12a generates hydrogen ions by electrolyzing water. Therefore, in the anode chamber 81 having the electrode 12a, the hydrogen ion concentration of the water is increased and becomes acidic electrolyzed water. A platinum electrode, for example, can be used as the electrode 12a.

The first water intake port 35 is an opening through which the acidic electrolyzed water stored in the acidic electrolyzed water reservoir 26 is introduced into the anode chamber 81 through the first water supply channel 47 . The first water intake port 35 is connected to the first water supply channel 47 .

The first outlet 36 is an opening for supplying acidic electrolyzed water containing hydrogen ions generated by the electrode 12 a to the water softening tank 4 through the first supply flow path 41 . The first outlet 36 is connected to the first supply channel 41 .

The cathode chamber 82 is a portion where alkaline electrolyzed water is generated during electrolysis of water. The cathode chamber 82 includes an electrode 12b, a second water intake port 37, and a second discharge port 38.

The electrode 12b serves as a cathode to generate hydroxide ions by electrolyzing water. Therefore, in the cathode chamber 82 provided with the electrode 12b, the hydroxide ion concentration of the water is increased, resulting in alkaline electrolyzed water. A platinum electrode, for example, can be used as the electrode 12b.

The second water intake port 37 is an opening through which the alkaline electrolyzed water stored in the alkaline electrolyzed water reservoir 28 is introduced into the cathode chamber 82 through the second water supply channel 48 . The second water intake port 37 is connected to the second water supply channel 48 .

The second discharge port 38 is an opening for supplying alkaline electrolyzed water containing hydroxide ions generated at the electrode 12 b to the neutralization tank 5 through the second supply flow path 42 . The second outlet 38 is connected with the second supply channel 42 .

That is, the electrolytic cell 11b uses the electrode 12a to electrolyze the water flowing in from the first water intake port 35 (the water supplied from the acidic electrolyzed water storage tank 26) to produce acidic electrolyzed water in the anode chamber 81. It is generated and discharged from the first outlet 36 . In addition, the electrolytic cell 11b uses the electrode 12b to electrolyze the water flowing in from the second water intake port 37 (the water supplied from the alkaline electrolyzed water storage tank 28), thereby producing alkaline electrolyzed water in the cathode chamber 82. It is generated and discharged from the second outlet 38 .

<<Acid Electrolyzed Water Tank and Alkaline Electrolyzed Water Tank>>
The acidic electrolyzed water reservoir 26 is a tank or container equipped with an air vent valve 27 . The acidic electrolyzed water storage tank 26 secures and stores water to be circulated in the first circulation flow path 40c when the weakly acidic cation exchange resin 9 is regenerated. The acidic electrolyzed water storage tank 26 supplies the acidic electrolyzed water containing the hardness component that has flowed through the water softening tank 4 to the electrolytic tank 11b.

Then, the acidic electrolyzed water that has flowed through the water softening tank 4 is passed through the electrolytic tank 11b and electrolyzed in the electrolytic tank 11b. The hydrogen ion concentration of the acidic electrolyzed water is increased by the hydrogen ions generated by electrolysis, and after passing through the water softening tank 4 , the acidic electrolyzed water is again passed to the acidic electrolyzed water storage tank 26 . Therefore, the acidic electrolyzed water used to regenerate the weakly acidic cation exchange resin 9 can be reused. Furthermore, since the acidic electrolyzed water is circulated without being discharged, regeneration can be performed in a state where the hydrogen ion concentration is increased, and the regeneration efficiency of the weakly acidic cation exchange resin 9 can be improved.

The alkaline electrolyzed water reservoir 28 is a tank or container equipped with an air vent valve 29 . The alkaline electrolyzed water storage tank 28 secures and stores water to be circulated in the second circulation flow path 40d (see FIG. 7) when the weakly basic anion exchange resin 10 is regenerated. The alkaline electrolyzed water storage tank 28 supplies the alkaline electrolyzed water containing anions that has flowed through the neutralization tank 5 to the electrolytic tank 11b.

Then, the alkaline electrolyzed water that has flowed through the neutralization tank 5 is passed through the electrolytic tank 11b and electrolyzed in the electrolytic tank 11b. The hydroxide ion concentration of the alkaline electrolyzed water is increased by the hydroxide ions produced by electrolysis, and after flowing through the neutralization tank 5, the alkaline electrolyzed water is again passed to the alkaline electrolyzed water storage tank . Therefore, the alkaline electrolyzed water used to regenerate the weakly basic anion exchange resin 10 can be reused. Furthermore, since the alkaline electrolyzed water is circulated without being discharged, regeneration can be performed in a state where the hydroxide ion concentration is increased, and the regeneration efficiency of the weakly basic anion exchange resin 10 can be improved.

<Acidic electrolyzed water circulation pump and alkaline electrolyzed water circulation pump>
The acidic electrolyzed water circulation pump 24 is a device that circulates the acidic electrolyzed water through the first circulation flow path 40c during the regeneration treatment by the regeneration device 8b. The acidic electrolyzed water circulation pump 24 is provided in a first water supply channel 47 that communicates between the acidic electrolyzed water storage tank 26 and the first water intake 35 of the electrolytic cell 11b.

The alkaline electrolyzed water circulation pump 25 is a device that circulates the alkaline electrolyzed water through the second circulation flow path 40d during the regeneration process by the regeneration device 8b. The alkaline electrolyzed water circulation pump 25 is provided in a second water supply channel 48 that communicates between the alkaline electrolyzed water storage tank 28 and the second water intake 37 of the electrolytic cell 11b.

By providing the acidic electrolyzed water circulation pump 24 and the alkaline electrolyzed water circulation pump 25 independently of each other, without mixing the acidic electrolyzed water and the alkaline electrolyzed water, the first circulation flow path 40c and the second circulation are respectively performed. Water can be passed through the channel 40d. In other words, it is possible to prevent the hydrogen ions in the acidic electrolyzed water and the hydroxide ions in the alkaline electrolyzed water from reacting and consuming each other. Therefore, compared to the case where acidic electrolyzed water and alkaline electrolyzed water are mixed and sent, acidic electrolyzed water with a higher hydrogen ion concentration can be sent to the water softening tank 4, and the hydroxide ion concentration is higher. Highly alkaline electrolyzed water can be sent to the neutralization tank 5 . Therefore, the regeneration efficiency of the water softening tank 4 and the neutralization tank 5 is improved. Also, the acidic electrolyzed water circulation pump 24 and the alkaline electrolyzed water circulation pump 25 are connected to a control unit 20b, which will be described later, so as to communicate wirelessly or by wire. The acidic electrolyzed water circulating pump 24 and the alkaline electrolyzed water circulating pump 25 are, for example, centrifugal pumps capable of supplying respective required flow rates to the first circulation flow path 40c and the second circulation flow path 40d to be described later during the regeneration process. be done.

<<Filtration Section>>
The filtration unit 15 is provided in the second supply channel 42 after the electrolytic bath 11b and before the second neutralization bath 5b.

The filtering unit 15 separates solids contained in the alkaline electrolyzed water supplied from the second outlet 38 of the electrolytic cell 11b. A solid is a reaction product that is precipitated by the involvement of the hardness component in the alkaline electrolyzed water flowing through the electrolytic cell 11b and the hydroxide ions generated by the electrode 12b. For example, when the hardness component contained in the alkaline electrolyzed water is magnesium ions, magnesium hydroxide is produced as a solid. If solids precipitated during the regeneration treatment are not removed, they accumulate in the neutralization tank 5, and hardness components are eluted from the solids, increasing the soft water hardness during the water softening treatment, that is, reducing the water softening performance. Therefore, by separating the precipitates in the filtering section 15, it is possible to suppress the inflow and accumulation of the precipitates in the second neutralization tank 5b, and to suppress the deterioration of the water softening performance during the water softening process.

The filtering unit 15 may take any form as long as it can separate the reaction product with the hardness component contained in the alkaline electrolyzed water supplied from the electrolytic cell 11b. Examples thereof include a form using a cartridge type filter, a filtration layer using granular filter media, a cyclone type solid-liquid separator, or a hollow fiber membrane.

<Flow path>
Next, referring to FIG. 7, the first circulation channel 40c and the second circulation channel 40d formed during the regeneration process of the water softening device 1b will be described. FIG. 7 is a diagram showing the state of each component during the resin regeneration treatment of the water softening device 1b.

As shown in FIG. 7 (white arrows), the first circulation flow path 40c allows the acidic electrolyzed water sent from the acidic electrolyzed water storage tank 26 by the acidic electrolyzed water circulation pump 24 to flow through the first water intake 35 of the electrolytic tank 11b, It is a flow path that circulates through the first discharge port 36, the second water softening tank 4b, and the first water softening tank 4a, and returns to the acidic electrolyzed water storage tank 26 for circulation. More specifically, the first circulation flow path 40c allows water sent from the acidic electrolyzed water storage tank 26 by the acidic electrolyzed water circulation pump 24 to pass through the first water supply flow path 47, the first water intake port 35, and the first discharge port 36. , first supply channel 41, on-off valve 63, second water softening tank 4b, first bypass channel 43, on-off valve 65, first water softening tank 4a, first recovery channel 45, on-off valve 61, acidic electrolysis It is a flow path that circulates and circulates in order of the water storage tank 26 .

As shown in FIG. 7 (black arrows), the second circulation flow path 40d allows the alkaline electrolyzed water sent from the alkaline electrolyzed water storage tank 28 by the alkaline electrolyzed water circulation pump 25 to flow through the second intake port 37 of the electrolytic tank 11b, It is a flow path that circulates through the second discharge port 38, the second neutralization tank 5b, and the first neutralization tank 5a, and returns to the alkaline electrolyzed water storage tank 28 for circulation. More specifically, the second circulation flow path 40 d allows the water sent out from the alkaline electrolyzed water storage tank 28 by the alkaline electrolyzed water circulation pump 25 to pass through the second water supply flow path 48 , the second water intake port 37 , and the second discharge port 38 . , filtration unit 15, second supply flow path 42, on-off valve 64, second neutralization tank 5b, second bypass flow path 44, on-off valve 66, first neutralization tank 5a, second recovery flow path 46, on-off valve 62, a flow path through which the alkaline electrolyzed water reservoir 28 circulates and circulates in this order.

<Control part>
Next, an example of the configuration of the control unit 20b will be described with reference to FIG. FIG. 9 is a functional block diagram showing each configuration of the control section 20b of the water softening device 1b. The control unit 20b includes a determination unit 22, a storage unit 23b, a first coefficient calculation unit 19c, a second coefficient calculation unit 19d, a third electrical conductivity calculation unit 19e, and a calculation unit 19b.

The control unit 20b controls a water softening process for softening raw water containing hardness components. Further, the control unit 20b controls the regeneration processing of the weakly acidic cation exchange resin 9 in the water softening tank 4 and the weakly basic anion exchange resin 10 in the neutralization tank 5 . Further, the control unit 20b controls switching of the water softening device 1 among the water softening process, the regeneration process, and the waste water process. At this time, the control unit 20b controls the operation of the electrolytic cell 11b, the acidic electrolyzed water circulation pump 24, the alkaline electrolyzed water circulation pump 25, the on-off valves 51 to 55, the on-off valves 61 to 66, and the on-off valves 73 to 76. control, switch between water softening treatment, regeneration treatment, and wastewater treatment, and execute each treatment.

Further, the control unit 20b is connected to the determination unit 22, the storage unit 23b, the first coefficient calculation unit 19c, the second coefficient calculation unit 19d, the third electrical conductivity calculation unit 19e, the calculation unit 19b, and the display unit 21, and Control the input and output of electrical conductivity, reference electrical conductivity, first coefficient, second coefficient, third electrical conductivity and calculated hardness in soft water.

Note that the control unit 20b has a computer system having a processor and memory. The computer system functions as a controller by the processor executing the program stored in the memory. Although the program executed by the processor is pre-recorded in the memory of the computer system here, it may be provided by being recorded in a non-temporary recording medium such as an optical disk or a memory card, or may be provided electronically such as the Internet. It may be provided through a communication line.

<<Judgment part>>
The determination unit 22 is connected to the soft water detection unit 6a, the storage unit 23b described later, and the calculation unit 19b. The determination unit 22 receives the electrical conductivity of the soft water detected by the soft water detection unit 6a and the reference electrical conductivity stored in the storage unit 23b. The determination unit 22 compares the electrical conductivity of the input soft water with the reference electrical conductivity, determines the period until the electrical conductivity of the soft water reaches the reference electrical conductivity as the first period, and determines the reference electrical conductivity The period after reaching is determined as the second period. The calculation method of the hardness component in the soft water in the calculator 19b is changed according to the determination result.

A specific determination method for the first period and the second period will be described with reference to FIGS. 10 and 11. FIG. FIG. 10 is a diagram showing changes in electrical conductivity of softened water by the water softening apparatus according to Embodiment 3 of the present invention. FIG. 11 is a diagram showing changes in ion concentration of softened water by the water softening apparatus according to Embodiment 3 of the present invention. FIG. 11(a) is a diagram showing changes in concentration of ions other than hardness components, such as sodium ions, and FIG. 11(b) is a diagram showing changes in concentration of hardness components. 10 and 11, the "total amount of raw water flow" is the total flow amount of raw water after completion of the regeneration process.

Specifically, taking the water softening process of the water softening device 1b as an example, as shown in FIG. Divided into F. Section D is a section in which the electrical conductivity of soft water is lower than the reference electrical conductivity. Section E is a section in which the electrical conductivity of soft water is approximately the same as the reference electrical conductivity (for example, about ±5% from the reference electrical conductivity). Section F is a section in which the electrical conductivity of soft water exceeds the reference electrical conductivity. The determination unit 22 determines the portion corresponding to the section D as the first period, and the portion corresponding to the sections E and F as the second period.

The reason why the determination unit 22 determines the first period and the second period in this way will be explained.

When the raw water is softened by flowing through the weakly acidic cation exchange resin 9 in the water softening tank 4, depending on the selectivity of the weakly acidic cation exchange resin 9, calcium ions, which are hardness components in the raw water, and Magnesium ions and monovalent cations other than hardness components, such as sodium ions, have different adsorption capacities to the weakly acidic cation exchange resin 9 . That is, the easiness of removal from raw water differs. Specifically, the hardness component is more likely to undergo an ion exchange reaction with the weakly acidic cation exchange resin 9 than the cations other than the hardness component, and is more likely to be removed from the raw water.

Therefore, as shown in FIG. 11(b), most of the hardness components in the raw water are removed from the raw water in section D, which is the first period, and even if the total raw water flow rate increases, the hardness component concentration significantly increases. gradually increases without increasing On the other hand, in the first period, section D, as shown in Fig. 11(a), monovalent cations such as sodium in soft water become difficult to remove from the raw water, and the sodium concentration in the raw water rises to the same level. do. This is because monovalent cations are less likely to be adsorbed on the weakly acidic cation exchange resin 9 than hardness components, and the ion adsorption performance of the weakly acidic cation exchange resin 9 is reduced due to an increase in the total flow of raw water. It's for. Thereafter, the concentration of monovalent cations such as sodium in the soft water temporarily exceeds the concentration of monovalent cations in the raw water. This is because the hardness component has a higher adsorption ability to the weakly acidic cation exchange resin 9 than the monovalent cation, so the monovalent cation once adsorbed to the weakly acidic cation exchange resin 9 and the raw water This is because an exchange reaction with the hardness component occurs.

Therefore, in section D, the increase in the electrical conductivity of soft water is mainly due to the electrical conductivity of monovalent cations such as sodium ions other than hardness components.

Further, in section E, due to the adsorption of cations to the weakly acidic cation exchange resin 9, the performance of the weakly acidic cation exchange resin 9 gradually decreases, and almost all of the hardness component is ion-exchanged, while sodium ions etc. remain in the raw water without being ion-exchanged. Specifically, as shown in FIG. 11(a), the sodium concentration in the soft water approaches the sodium concentration in the raw water from a value exceeding the sodium concentration in the raw water. That is, monovalent cations such as sodium in the raw water are not adsorbed to the weakly acidic cation exchange resin 9 . On the other hand, as shown in FIG. 11(b), in section E, due to the deterioration in the performance of the weakly acidic cation exchange resin 9, it becomes difficult for the hardness components in the raw water to be adsorbed to the weakly acidic cation exchange resin 9. The rate of increase in hardness component concentration in section D is higher than that in section D. Therefore, in section E, the concentration of hardness component ions in soft water increases and the concentration of ions other than hardness components decreases at the same time, so the electric conductivity of soft water continues to maintain a similar value.

In addition, in section F, since most of the hydrogen ions of the terminal functional groups of the weakly acidic cation exchange resin 9 are in a state of being exchanged with cations in the raw water, monovalent cations in the raw water and Almost no ion exchange reaction with hardness components occurs. Therefore, the hardness component concentration in soft water continues to rise at the same speed as in section E. Therefore, in section F, most of the increase in the electrical conductivity of soft water is due to the increase in the concentration of hardness components.

That is, the first period, section D, is a section in which the hardness component concentration in soft water gradually increases, and the second period, section E and section F, in which the hardness component concentration in soft water increases relatively quickly. This is the section where In the first period, a third electrical conductivity, which will be described later, is calculated by a third electrical conductivity calculator 19e, which will be described later, based on a first coefficient and a second coefficient, which will be described later, and is input to the calculator 19b. In the second period, the reference conductivity stored in the storage unit 23b, which will be described later, is input to the calculation unit 19b. The third electrical conductivity is a value indicating the electrical conductivity corresponding to ions other than the hardness component in the first period, and the reference electrical conductivity is the electrical conductivity corresponding to the ions other than the hardness component in the second period. is the value shown. That is, depending on the determination result of the determination unit 22, the calculation unit 19b uses either the third electric conductivity or the reference electric conductivity for calculating the hardness component.

<<storage unit>>
The storage unit 23b stores the electrical conductivity value of the soft water corresponding to the section D in FIG. 9 as the reference electrical conductivity. The stored reference electrical conductivity is output to the determination unit 22 and used to determine the interval D, interval E, interval F, and the first period and the second period.

The storage unit 23b stores the electrical conductivity corresponding to the hardness component in soft water, the ion concentration other than the hardness component, and the electrical conductivity of the soft water.

The storage unit 23b is connected to the first coefficient calculation unit 19c, and calculates the electrical conductivity corresponding to the hardness component in the soft water stored in the storage unit 23b, the ion concentration other than the hardness component, and the electrical conductivity of the soft water as the first coefficient. It transmits to the calculation part 19c.

The storage unit 23b is also connected to the second coefficient calculation unit 19d, and transmits the ion concentration other than the hardness component stored in the storage unit 23b to the second coefficient calculation unit 19d.

For the electrical conductivity corresponding to the hardness component in the soft water, the ion concentration other than the hardness component, and the electrical conductivity of the soft water, the trial run data when the water softening device 1b was installed were used as fixed values. Alternatively, a value may be presumed and set according to the water quality of each region. Also, regarding the timing of the electrical conductivity to be used as the reference electrical conductivity, the total flow of raw water and the amount of change in the electrical conductivity of soft water with respect to the total flow of raw water (slope in the graph) are taken into consideration. The electrical conductivity of soft water when the amount of change in the electrical conductivity of the soft water with respect to the total flow of raw water is less than a certain value (e.g., 0.1 μS/cm L or less), or when the variation in the electrical conductivity is the smallest. is preferably taken as the reference electrical conductivity. In addition, by updating and storing the reference electric conductivity at regular intervals (for example, one month), it is possible to set the reference electric conductivity corresponding to the change even when the ionic component composition of the raw water changes. can.

<<First Coefficient Calculation Unit and Second Coefficient Calculation Unit>>
When the determination result of the determination unit 22 is the first period, the first coefficient calculation unit 19c calculates a first coefficient that is used as input data of the calculation unit 19b when calculating the third electrical conductivity.

The first coefficient calculation unit 19c uses the electrical conductivity C _H corresponding to the hardness component in the soft water stored in the storage unit 23b, the ion concentration [E] other than the hardness component, and the electrical conductivity C _(H+E) of the soft water. to calculate the first coefficient _k1 . The first coefficient is a value corresponding to the ratio of the concentration of ions other than hardness components in soft water to the electrical conductivity.

Specifically, the electrical conductivity of soft water is represented by the sum of the electrical conductivity corresponding to the hardness component in the soft water and the electrical conductivity corresponding to the ions other than the hardness component in the soft water. Also, the electrical conductivity corresponding to ions other than hardness components can be displayed by multiplying the concentration of ions other than hardness components in soft water by the first coefficient. That is, if the electrical conductivity corresponding to the hardness component in soft water is _CH , the ion concentration other than the hardness component is [E], and the electrical conductivity of soft water is C _{(H + E)} , the first coefficient k ₁ is the following formula (1).

C _{(H + E)} - _CH = k ₁ × [E] (1)
The second coefficient calculation unit 19d calculates a second coefficient _k2 that is used as input data of the calculation unit 19b when calculating the third electric conductivity when the determination result of the determination unit 22 is the first period.

The second coefficient calculation unit 19d calculates the second coefficient using the ion concentration [E] other than the hardness component stored in the storage unit 23b. The second coefficient is a value corresponding to the rate of change in concentration of ions other than hardness components in soft water according to the flow rate of raw water.

Specifically, the concentration of ions other than the hardness components in the soft water is calculated by the sum of the concentration of the ions other than the hardness components in the soft water at the start of softening, the flow rate of the raw water, and the multiplication of the second coefficient. . The concentration of ions other than hardness components in soft water after the start of softening is the increase in the concentration of ions other than hardness components in soft water according to the flow rate of raw water to the ion concentration other than hardness components in soft water at the start of softening. It can be calculated by adding the amount. That is, if the water flow from the start of water softening to the present time is Q, and the ion concentration other than the hardness component in the soft water when the water flow is 0 L is [E] (Q = 0), the second coefficient _k2 is as follows. (2).

[E]=k ₂ ×Q+[E] (Q=0)…………(2)
Then, the first coefficient _k1 and the second coefficient _k2 can be calculated by the following equations (3) and (4).

k ₁ = (C _{(H + E)} - C _H )/[E] (3)
k ₂ = [E] - [E] (Q = 0) / Q (4)
<<Third electrical conductivity calculator>>
The third electrical conductivity calculator 19e is connected to the first coefficient calculator 19c and the second coefficient calculator 19d, and calculates the third electrical conductivity based on the first coefficient, the second coefficient, and the current flow rate. calculate. The third electrical conductivity is electrical conductivity corresponding to ions other than hardness components. The calculated third electrical conductivity is transmitted to the calculator 19b. Further, the third electric conductivity _CE can be expressed by the following formula (5) from the formulas (3) and (4).

C _E = k ₁ × (k ₁ × Q + [E] (Q = 0)) (5)
<<calculation unit>>
The calculator 19b calculates and outputs the hardness component in the soft water based on the electrical conductivity of the soft water detected by the soft water detector 6a. The calculation method differs depending on whether the determination by the determination unit 22 is the first period or the second period.

In the first period, for example, using the first coefficient and the second coefficient input from the storage unit 23b, the third electrical conductivity corresponding to ions other than the hardness of the neutralized soft water is calculated, and the electrical conductivity of the soft water The value calculated by subtracting the third electrical conductivity from is multiplied by a predetermined value.

In the case of the second period, for example, the reference electrical conductivity is subtracted from the electrical conductivity of soft water, and the value obtained by subtraction is multiplied by a predetermined value.

As the predetermined value, the constant of proportionality between the "difference between the electrical conductivity of the soft water and the third electrical conductivity" and the "hardness component in the soft water" is used in the first period. In the second period, the constant of proportionality between the "difference between the electrical conductivity of the soft water and the reference electrical conductivity" and the "hardness component in the soft water" is used as the predetermined value. Generally, the electrical conductivity of water is proportional to the concentration of ionic components in water, and the higher the concentration of ionic components in water, the greater the electrical conductivity. The constants of proportionality for ion concentration and electrical conductivity differ depending on the ion species. In the ``difference between the electrical conductivity of soft water and the third electrical conductivity'' in the first term or the ``difference between the electrical conductivity of soft water and the reference electrical conductivity'' in the second term, the electrical conductivity mainly due to the hardness component Therefore, by adjusting the setting of the predetermined value according to the concentration of cations corresponding to the country or region where the water softening device 1b is used, the hardness component in the soft water can be calculated more accurately.

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

Next, the operation of the water softening device 1b will be described.

<Water softening treatment, regeneration treatment, and wastewater treatment>
Next, referring to FIG. 8, the water softening treatment, regeneration treatment, and waste water treatment of the water softening device 1b will be described. FIG. 8 is a diagram showing the operating state of the water softening device 1b. In the water softening process, the regeneration process, and the drainage process, the control unit 20b, as shown in FIG. The valve 76, the electrode 12 of the electrolytic bath 11b, the acidic electrolyzed water circulation pump 24, and the alkaline electrolyzed water circulation pump 25 are switched and controlled so as to be in the respective circulation states.

Here, "ON" in FIG. 8 indicates a state in which the soft water detection unit 6a is energized, a state in which the corresponding on-off valve is "open", a state in which the electrode 12 is energized, and an acidic electrolyzed water circulation pump 24, The state in which the alkaline electrolyzed water circulation pump 25 is operating is shown. Blanks indicate the state in which the soft water detection unit 6a is not energized, the corresponding on-off valve is "closed", the electrode 12 is not energized, and the acidic electrolyzed water circulation pump 24 and the alkaline electrolyzed water circulation pump 25 are stopped. state respectively.

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

In the water softening device 1b, as shown in FIG. 8, in the water softening process (during water softening), the on-off valve 55 provided at the water intake 7 is opened while the on-off valves 51 to 54 are open. As a result, raw water containing hardness components from the outside flows through the water softening tank 4 and the neutralization tank 5, so that the water softening device 1b can take out softened water (neutral soft water) from the water intake 7. can. At this time, the on-off valves 61 to 66 and the on-off valves 73 to 76 are all closed. Further, the operation of the electrode 12 of the electrolytic bath 11b, the acidic electrolyzed water circulation pump 24, and the alkaline electrolyzed water circulation pump 25 is also stopped.

As shown in FIG. 6, in the water softening process of the water softening device 1b, the raw water supplied in the same flow path as the water softening device 1 is supplied from the inlet 2 to the flow path 30, the first water softening tank 4a, the flow path 31, first neutralization tank 5a, channel 32, second water softening tank 4b, channel 33, and second neutralization tank 5b. Hardness components in the raw water are absorbed in the water softening tank 4 , and the raw water flows into the neutralizing tank 5 as acidic soft water. Hydrogen ions are adsorbed on the acidic soft water in the neutralization tank 5 to become neutralized soft water. Then, the neutralized soft water whose hardness component is reduced compared to the raw water flows through the flow path 34 and is taken out of the water softening device 1b through the water intake port 7 .

Then, in the water softening device 1b, the regeneration process is executed when the time period specified by the control unit 20b comes or when the water softening process exceeds a predetermined time period.

<< Regeneration processing >>
The operation during regeneration processing by the regeneration device 8b of the water softening device 1b will be described in order with reference to the columns "during injection of water" and "during regeneration" in FIG.

First, as shown in FIG. 8, the on-off valve 51 and the on-off valve 61 are opened during water injection. As a result, the water softening device 1b introduces the raw water from the inlet 2 through the first recovery channel 45 into the acidic electrolyzed water storage tank 26 by the pressure of the raw water. Also, the on-off valve 52 and the on-off valve 62 are opened. As a result, the raw water that has flowed in from the inlet 2 is introduced into the alkaline electrolyzed water storage tank 28 through the second recovery channel 46 after passing through the first water softening tank 4a. At this time, the on-off valves 53 to 55, the on-off valves 63 to 66, and the on-off valves 73 to 76 are closed. By storing a predetermined amount of water in the acidic electrolyzed water storage tank 26 and the alkaline electrolyzed water storage tank 28 according to the respective flow rates of the first circulation flow path 40c and the second circulation flow path 40d, the regeneration device 8b can It is possible to secure the amount of water during regeneration.

Next, during regeneration, the on-off valves 51 to 55, the on-off valves 75 and 76 are closed, and the on-off valves 61 to 66, the on-off valves 73 and 74 are opened, as shown in FIG. Thus, a first circulation channel 40c and a second circulation channel 40d are formed.

Then, when the electrode 12a of the electrolytic cell 11b and the acidic electrolyzed water circulation pump 24 are operated in the first circulation flow path 40c, the acidic electrolyzed water generated by the electrode 12a flows through the first supply flow path 41 and undergoes the second softening. The water is sent into the tank 4b and flows through the second weakly acidic cation exchange resin 9b inside. Then, the acidic electrolyzed water that has flowed through the second water softening tank 4b flows through the first bypass channel 43, is sent into the first water softening tank 4a, and flows through the first weakly acidic cation exchange resin 9a inside. do. That is, by passing acidic electrolyzed water through the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b, the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin The cations (hardness components) adsorbed to 9b undergo an ion exchange reaction with hydrogen ions contained in the acidic electrolyzed water. As a result, the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b are regenerated. After that, the acidic electrolyzed water that has flowed through the first weakly acidic cation exchange resin 9 a contains cations and flows into the first recovery channel 45 . That is, the acidic electrolyzed water containing cations that has passed through the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b passes through the first bypass flow path 43 and the first recovery flow path 45 to produce an acidic It is collected in the electrolyzed water reservoir 26 .

On the other hand, in the second circulation flow path 40d, when the electrode 12b of the electrolytic cell 11b and the alkaline electrolyzed water circulation pump 25 are operated, the alkaline electrolyzed water generated in the electrode 12b passes through the second supply flow path 42 to the second neutralization. The water is sent into the tank 5b and flows through the second weakly basic anion exchange resin 10b inside. Then, the alkaline electrolyzed water that has flowed through the second neutralization tank 5b flows through the second bypass flow path 44, is sent into the first neutralization tank 5a, and displaces the first weakly basic anion exchange resin 10a inside. circulate. That is, by passing alkaline electrolyzed water through the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b, the first weakly basic anion exchange resin 10a and the second weakly basic The anions adsorbed on the anion exchange resin 10b undergo an ion exchange reaction with hydroxide ions contained in the alkaline electrolyzed water. This regenerates the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b. After that, the alkaline electrolyzed water that has flowed through the second weakly basic anion exchange resin 10 b contains anions and flows into the second recovery channel 46 . That is, the alkaline electrolyzed water containing anions that has flowed through the first weakly basic anion exchange resin 10a and the second weakly basic anion exchange resin 10b passes through the second bypass channel 44 and the second recovery channel 46. is collected in the alkaline electrolyzed water storage tank 28.

Thus, the first circulation flow path 40c replaces the hydrogen ions of the acidic electrolyzed water with the hardness component ions of the second weakly acidic cation exchange resin 9b and the first weakly acidic cation exchange resin 9a. The replaced hardness component ions are collected in the acidic electrolyzed water reservoir 26 . Further, the second circulation flow path 40d replaces hydroxide ions of the alkaline electrolyzed water with anions of the second weakly basic anion exchange resin 10b and the first weakly basic anion exchange resin 10a. The replaced anions are recovered in the alkaline electrolyzed water reservoir 28 .

Then, the acidic electrolyzed water containing the hardness component ions recovered in the acidic electrolyzed water storage tank 26 is sent to the electrode 12a side of the electrolytic cell 11b by the acidic electrolyzed water circulation pump 24 . Also, the alkaline electrolyzed water containing anions collected in the alkaline electrolyzed water storage tank 28 is sent to the electrode 12b side of the electrolytic cell 11b by the alkaline electrolyzed water circulation pump 25. FIG. The acidic electrolyzed water and the alkaline electrolyzed water are electrolyzed again in the electrolytic cell 11b to produce hydrogen ions and hydroxide ions, respectively. The electrolyzed water (acidic electrolyzed water, alkaline electrolyzed water) electrolyzed again in the electrolytic cell 11b is used for regeneration of the weakly acidic cation exchange resin 9 and weakly basic anion exchange resin 10, respectively. At this time, some hardness component ions on the electrode 12a side are attracted to the electrode 12b, while some negative ions on the electrode 12b side are attracted to the electrode 12a. Therefore, on the electrode 12b side, the attracted hardness component ions react with hydroxide ions and the like in the alkaline electrolyzed water, and are deposited as solids. For example, when the hardness component in the acidic electrolyzed water is calcium ions, the alkaline electrolyzed water produces calcium hydroxide, or combines with carbonate ions normally present in water to produce calcium carbonate. Therefore, in the water softening device 1b, acidic electrolyzed water containing a large amount of hydrogen ions and a small amount of hardness component ions flows into the water softening tank 4, and the hardness components are regenerated into the weakly acidic cation exchange resin 9 in the water softening tank 4. Adsorption can be suppressed. Further, in the water softening device 1b, alkaline electrolyzed water containing a large amount of hydroxide ions and a small amount of other anions contained in the raw water flows into the neutralization tank 5, and the other anions contained in the raw water are neutralized. Re-adsorption to the weakly basic anion exchange resin 10 in the tank 5 can be suppressed. Therefore, it is possible to suppress the deterioration of the regeneration efficiency of the water softening tank 4 and the neutralization tank 5, and shorten the regeneration time.

After that, the alkaline electrolyzed water is removed from the second discharge port 38 by the solids produced by the reaction when flowing to the filtration unit 15, and is again passed through the second neutralization tank 5b through the second supply flow path 42. . Further, the acidic electrolyzed water is again supplied from the first discharge port 36 to the second water softening tank 4b via the first supply flow path 41 .

Then, in the water softening device 1b, the operation of the electrode 12, the acidic electrolyzed water circulation pump 24, and the alkaline electrolyzed water circulation pump 25 is stopped when the regeneration treatment is completed. Also, by opening the on-off valve 75 and the on-off valve 76, the process proceeds to wastewater treatment. It should be noted that the end of the regeneration process may be set for a certain period of time from the start of the regeneration process (when the electrode 12 starts operating).

<< Wastewater treatment >>
In the water softening device 1b, when the regeneration process is completed, the process shifts to wastewater treatment. Here, the drainage treatment is a treatment for draining the acidic electrolyzed water and the alkaline electrolyzed water remaining in the circulation flow path 40 .

Next, the operation of the water softening device 1b during waste water treatment will be described with reference to the "Drain" column in FIG.

In the water softening device 1b, as shown in FIG. 8, in the wastewater treatment (at the time of drainage), the on-off valves 51 to 55 are closed, and the on-off valves 61 to 66 and the on-off valves 73 to 76 are opened. do.

As a result, the acidic electrolyzed water remaining in the first circulation flow path 40 c can flow into the acidic electrolyzed water storage tank 26 . Also, the alkaline electrolyzed water remaining in the second circulation flow path 40 d can flow into the alkaline electrolyzed water storage tank 28 .

Next, when the on-off valve 75 is opened, the action of the air vent valve 27 allows the acidic electrolyzed water in the acidic electrolyzed water storage tank 26 to be discharged to the outside of the apparatus. Further, when the on-off valve 76 is opened, the action of the air vent valve 29 allows the alkaline electrolyzed water in the alkaline electrolyzed water storage tank 28 to be discharged to the outside of the apparatus.

By performing waste water treatment, when the water softening treatment is restarted, the acidic electrolyzed water and alkaline electrolyzed water remaining in the circulation flow path 40 are mixed with the raw water flowing in from the inlet 2 and discharged from the water intake 7. can be prevented.

Then, in the water softening device 1b, when the wastewater treatment is completed, the on-off valves 61 to 66 and 73 to 76 are closed, and the on-off valves 51 to 55 are opened to shift to the water softening treatment. do. It should be noted that the end of the wastewater treatment may be set when a certain period of time has elapsed from the start of the wastewater treatment.

In this way, the water softening device 1b repeatedly performs the water softening process, the regeneration process, and the waste water process.

<<Calculation of hardness of soft water>>
A method for calculating the hardness of soft water in the water softening device 1b will be described.

The water softening device 1b calculates the hardness of soft water during the water softening process. First, the soft water detector 6a detects the electric conductivity of the soft water flowing through the channel 34. As shown in FIG. The detected electric conductivity of the soft water is transmitted to the determination unit 22 . Further, the storage unit 23 b stores the reference electrical conductivity and transmits the reference electrical conductivity to the determination unit 22 .

The determination unit 22 compares the electrical conductivity of the soft water input from the soft water detection unit 6a with the reference electrical conductivity input from the storage unit 23b, and determines the period until the electrical conductivity of the soft water reaches the reference electrical conductivity. is determined as the first period, and the period after reaching the reference electrical conductivity is determined as the second period.

When it is determined to be the first period, the third electric conductivity calculation unit 19e calculates the current flow rate, the first coefficient input from the first coefficient calculation unit 19c, and the second coefficient input from the second coefficient calculation unit 19d. Based on the two coefficients, the third electric conductivity is calculated and output to the calculation unit 19 .

Next, the calculator 19b calculates the hardness by multiplying the value calculated by subtracting the electrical conductivity and the third electrical conductivity of the soft water detected by the soft water detector 6a by a predetermined value. The hardness calculated by the calculation unit 19b is transmitted to the display unit 21 and displayed on the display unit 21. FIG.

When it is determined to be the second period, the calculation unit 19b subtracts based on the electrical conductivity of the soft water detected by the soft water detection unit 6a and the reference electrical conductivity output from the determination unit 22 or the storage unit 23. The hardness is calculated by multiplying the calculated value by a predetermined value. The hardness calculated by the calculation unit 19b is transmitted to the display unit 21 and displayed on the display unit 21. FIG.

As described above, according to the water softening device 1b according to Embodiment 3, the following effects can be obtained.

The water softening device 1b includes a water softening tank 4, a neutralizing tank 5, a water softening detection unit 6a, a determination unit 22, a storage unit 23b, a first coefficient calculation unit 19c, a second coefficient calculation unit 19d, A third electrical conductivity calculation unit 19e, a calculation unit 19b, and a display unit 21 are provided. The water softening tank 4 softens raw water containing hardness components with a weakly acidic cation exchange resin 9 . Neutralization tank 5 neutralizes the pH of the softened water that has passed through water softening tank 4 with weakly basic anion exchange resin 10 . The softened water detector 6 a detects the electric conductivity of the softened water that has passed through the water softening tank 4 and the neutralizing tank 5 . The determination unit 22 compares the electrical conductivity of the soft water detected by the soft water detection unit 6a with the reference electrical conductivity, and determines the period until the electrical conductivity of the soft water reaches the reference electrical conductivity as the first term, the reference electrical conductivity The period after reaching the degree is determined as the second period. The storage unit 23b stores the electric conductivity of the soft water when the amount of change in the electric conductivity of the soft water with respect to the flow rate of the raw water is small as the reference electric conductivity. The storage unit 23b also stores the electrical conductivity corresponding to the hardness of the neutralized soft water, the electrical conductivity of the soft water, and the soft water target ion concentration, which is the ion concentration other than the hardness components in the soft water. The first coefficient calculation unit 19c and the second coefficient calculation unit 19d are the electrical conductivity corresponding to the hardness of the neutralized soft water output from the storage unit 23b, the electrical conductivity of the soft water, and the concentration of ions other than the hardness components in the soft water. The first coefficient and the second coefficient are calculated based on the soft water target ion concentration. The third electrical conductivity calculator 19e calculates the third electrical conductivity based on the first coefficient calculated by the first coefficient calculator 19c and the second coefficient calculated by the second coefficient calculator 19d. The calculation unit 19a calculates the hardness component in the soft water based on the determination result of the determination unit 22. FIG. If the determination result is the first stage, the hardness of the soft water is calculated based on the electrical conductivity of the soft water output from the soft water detection unit 6a and the third electrical conductivity output from the third electrical conductivity calculation unit 19e. Calculate and output the components. If the determination result is the second period, the hardness component in the soft water is calculated and output based on the electrical conductivity of the soft water output by the soft water detection unit 6a and the reference electrical conductivity output from the storage unit 23b. do. The display unit 21 notifies the hardness of the soft water calculated by the calculation unit 19a. The water softening device 1a is configured such that raw water flows through the water softening tank 4, the neutralization tank 5, and the soft water detector 6a in this order.

According to such a configuration, it is possible to calculate the hardness value corresponding to the hardness component in the soft water by predicting the rate of increase in the electrical conductivity corresponding to the ions other than the hardness component in the soft water in the first period. Specifically, in the second embodiment, the hardness of the soft water is assumed to be 0 in the first period until the electrical conductivity of the soft water reaches the reference electrical conductivity. Unlike form 2, in the first period until the electrical conductivity of soft water reaches the reference electrical conductivity, based on the first coefficient and the second coefficient, the third By predicting the change behavior of the electrical conductivity and subtracting the predicted third electrical conductivity from the electrical conductivity of the soft water, the hardness component of the soft water can be calculated. Therefore, the calculation unit 19b can calculate the overall concentration change of the hardness component including the first and second periods of the water softening treatment, and the display unit 21 can display the result. That is, even in the first period, it is possible to calculate the hardness change of the soft water obtained from the water intake 7, so that the hardness of the soft water can be known more accurately.

The present invention has been described above based on the embodiments. Those skilled in the art will understand that these embodiments are merely examples, and that various modifications can be made to combinations of each component or each treatment process, and such modifications are also within the scope of the present invention. I am where I am.

In the water softening device 1 according to Embodiment 1, instead of measuring the electrical conductivity in the raw water detection unit 3 and acquiring the first electrical conductivity corresponding to ions other than the hardness component in the raw water in the acquisition unit 17, other It is also possible to measure the amount of ions other than the hardness component using the means of (1), and obtain the electrical conductivity corresponding to the ions other than the hardness component obtained from the measurement as the first electrical conductivity. Other methods include measurements using devices such as ion chromatography and pack tests. can be calculated more accurately.

Further, in the water softening device 1, the water softening device 1a, and the water softening device 1b according to Embodiments 1, 2, and 3, the water softening tank 4 and the neutralization tank 5 are assumed to be two each. However, it is not limited to this. For example, each may be one, or three or more. Basically, when the total amount of the weakly acidic cation exchange resin 9 and the weakly basic anion exchange resin 10 used in the water softening device 1 and the water softening devices 1a and 1b is constant, the water softening tank 4 and As the number of divisions of the neutralization tank 5 is increased, the number of times that water softening and neutralization are alternately performed during the water softening treatment increases, and the water softening performance can be further improved.

Further, in the water softening device 1, the water softening device 1a, and the water softening device 1b according to Embodiments 1, 2, and 3, the channel length and flow rate of the first water softening tank 4a and the second water softening tank 4b Although the road cross-sectional areas were assumed to be equal, this is not the case. For example, the channel length or the channel cross-sectional area may be different, or both the channel length and the channel cross-sectional area may be different. Even in this way, the same effect as in the first embodiment can be obtained. The same applies to the first neutralization tank 5a and the second neutralization tank 5b.

Further, in the water softening device 1, the water softening device 1a, and the water softening device 1b according to Embodiments 1, 2, and 3, the first weakly acidic cation exchange resin filled in the first water softening tank 4a Although the volumes of the second weakly acidic cation exchange resin 9b filled in the second water softening tank 4b and the second weakly acidic cation exchange resin 9a were assumed to be equal, this is not the only option. For example, the volumes of the first weakly acidic cation exchange resin 9a and the second weakly acidic cation exchange resin 9b may be different, or different kinds of weakly acidic cation exchange resins 9 may be used. Thereby, the water softening performance can be adjusted, and the water softening device 1 having the water softening performance suitable for the purpose can be obtained. The same applies to the first neutralization tank 5a and the second neutralization tank 5b.

Further, in the water softening device 1, the water softening device 1a, and the water softening device 1b according to Embodiments 1, 2, and 3, the acidic electrolyzed water is supplied to the second water softening tank 4b and the first water softening tank 4a in that order. Although it was distributed, it is not limited to this. For example, the acidic electrolyzed water may be circulated through the first water softening tank 4a and the second water softening tank 4b in this order. Furthermore, in the water softening apparatus 1 according to Embodiment 1, the acidic electrolyzed water is circulated from the downstream side of the water softening tank 4, but it may be circulated from the upstream side. Also in this way, the water softening tank 4 can be regenerated.

Further, in the water softening device 1, the water softening device 1a, and the water softening device 1b according to Embodiments 1, 2, and 3, when the time period specified by the control unit 20 or the control unit 20b comes, or when the softened water Although the reproduction process is executed when the conversion process exceeds a certain period of time, the present invention is not limited to this. For example, when the hardness component amount in the soft water calculated by the calculation unit 19 exceeds a preset reference value, the control unit 20 or the control unit 20b operates the electrolytic cell 11 or the electrolytic cell 11b to perform the regeneration process. may be executed. As a result, it is possible to determine the execution of the regeneration process based on the amount of hardness components in the soft water. Therefore, the state of the weakly acidic cation exchange resin 9 in the water softening tank 4 can be determined more accurately, and the weakly acidic cation exchange resin 9 and the weakly basic anion exchange resin 10 can be regenerated at more appropriate timing. It can be performed.

The water softener according to the present invention can be applied to a water purifier installed at a place of use (POU: Point of Use) or a water purifier installed at a building entrance (POE: Point of Entry).

1 water softening device 1a water softening device 1b water softening device 2 inlet 3 raw water detector 4 water softening tank 4a first water softening tank 4b second water softening tank 5 neutralization tank 5a first neutralization tank 5b second neutralization Tank 6, 6a Soft water detector 7 Water intake 8, 8b Regeneration device 9 Weakly acidic cation exchange resin 9a First weakly acidic cation exchange resin 9b Second weakly acidic cation exchange resin 10 Weakly basic anion exchange resin 10a Second First weakly basic anion exchange resin 10b Second weakly basic anion exchange resin 11, 11b Electrolytic tank 12 Electrode 12a Electrode 12b Electrode 13 Treatment tank 14 Water pump 15 Filtration part 16 Air vent valve 17 Acquisition part 18 Calibration part 19, 19a , 19b calculation unit 19c first coefficient calculation unit 19d second coefficient calculation unit 19e third electrical conductivity calculation unit 20, 20b control unit 21 display unit 22 determination unit 23, 23b storage unit 24 acidic electrolyzed water circulation pump 25 alkaline electrolyzed water circulation pump 26 acidic electrolyzed water tank 27 air vent valve 28 alkaline electrolyzed water tank 29 air vent valve 30, 31, 32, 33, 34 flow path 35 first water intake 36 first discharge port 37 second water intake port 38 second discharge port 40 Circulation channels 40a, 40c First circulation channels 40b, 40d Second circulation channel 41 First supply channel 42 Second supply channel 43 First bypass channel 44 Second bypass channel 45 First recovery channel 46 Second recovery channel 47 First water supply channel 48 Second water supply channel 50 Water supply channel 51, 52, 53, 54, 55 On-off valves 61, 62, 63, 64, 65, 66 On-off valves 71, 72, 73 , 74, 75, 76 on-off valve 80 diaphragm 81 anode chamber 82 cathode chamber

Claims (13)

a water softening tank for softening raw water containing hardness components with a weakly acidic cation exchange resin;
a neutralization tank for neutralizing the pH of acidic soft water generated by passing through the water softening tank with a weakly basic anion exchange resin;
a soft water detection unit that detects electrical conductivity of neutralized soft water generated by passing through the neutralization tank;
an acquisition unit that acquires a first electrical conductivity corresponding to ions other than the hardness component in the raw water;
a calibration unit that calibrates the electrical conductivity of the soft water based on the first electrical conductivity acquired by the acquisition unit and outputs a second electrical conductivity;
A water softening device, comprising: a calculation unit that calculates hardness component information based on the second electrical conductivity. The calibration unit
When the electrical conductivity of the soft water is equal to or higher than the first electrical conductivity, the second electrical conductivity is set based on the difference between the electrical conductivity of the soft water and the first electrical conductivity. 2. The water softening device according to 1. The hardness component information includes the hardness component concentration of the neutralized soft water,
The calculation unit
3. The water softening device according to claim 1, wherein the hardness component concentration is set to 0 when the electrical conductivity of the soft water is less than the first electrical conductivity. The water softening device according to any one of claims 1 to 3, further comprising a display section for displaying the hardness component information. an electrolytic cell for producing acidic electrolyzed water and alkaline electrolyzed water;
Further comprising a control unit for controlling the operation of the electrolytic cell,
5. The method according to any one of claims 1 to 4, wherein the controller operates the electrolytic cell based on the hardness component information output from the calculator when the hardness component information exceeds a reference value. Water softener as described. The water softening device according to any one of claims 1 to 5, further comprising a raw water detector that measures the raw water electrical conductivity of the raw water. The water softening device according to any one of claims 1 to 5, wherein the first electrical conductivity is a predetermined value according to the water quality of the raw water. a water softening tank for softening raw water containing hardness components with a weakly acidic cation exchange resin;
a neutralization tank for neutralizing the pH of the acidic soft water that has passed through the water softening tank with a weakly basic anion exchange resin;
a soft water detection unit that detects electrical conductivity of neutralized soft water generated by passing through the neutralization tank;
a determination unit that determines a first period until the electrical conductivity of the soft water reaches the first predetermined value and a second period after the electrical conductivity of the soft water reaches the first predetermined value;
a calculation unit that calculates hardness component information based on the electrical conductivity of the soft water,
The determination unit includes a water softening device that stores electrical conductivity of soft water at the beginning of the second period as a reference electrical conductivity. The hardness component information includes the hardness component concentration of the neutralized soft water,
The calculation unit
9. The water softening device according to claim 8, wherein the hardness component concentration is set to 0 in the first period. The calculation unit
10. The water softening apparatus according to claim 8, wherein in the second period, the hardness component concentration is calculated based on the difference between the electrical conductivity of the soft water and the reference electrical conductivity. The storage unit
storing the electrical conductivity corresponding to the hardness of the neutralized soft water, the electrical conductivity of the soft water of the neutralized soft water, and the soft water target ion concentration, which is the ion concentration other than the hardness component in the neutralized soft water,
The calculation unit
a first coefficient calculation unit that calculates a first coefficient corresponding to a ratio between the concentration of ions other than hardness components in the neutralized soft water in the first period and the electrical conductivity;
a second coefficient calculation unit that calculates a second coefficient corresponding to a rate of change of the concentration of ions to be softened in the neutralized soft water according to the flow rate of the raw water;
The water softening device according to claim 8, further comprising a third electrical conductivity calculator that calculates a third electrical conductivity corresponding to ions other than the hardness component in the raw water. The third electrical conductivity calculator,
calculating the third electrical conductivity based on the first coefficient and the second coefficient;
The calculation unit
12. The water softening apparatus according to claim 11, wherein in the first period, the hardness component concentration is calculated based on the difference between the electrical conductivity of the soft water and the third electrical conductivity. The calculation unit
13. The water softening apparatus according to claim 11 or 12, wherein in the second period, the hardness component concentration is calculated based on the difference between the electrical conductivity of the soft water and the reference electrical conductivity.

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