Water softening unit

Abstract

To provide a water softening device capable of improving the regeneration efficiency of ion exchange resins. [Solution] The water softening device 100 comprises a water softening chamber 2 that removes hardness components from the water to be treated W1 using a weakly acidic cation exchange resin 22, a neutralization chamber 3 that neutralizes the water to be treated using a weakly basic anion exchange resin 32, a first electrode pair 4 that generates hydrogen ions to regenerate the weakly acidic cation exchange resin 22, a second electrode pair 5 that generates hydroxide ions to regenerate the weakly basic anion exchange resin 32, and an ion concentration chamber 6 provided between the water softening chamber 2 and the neutralization chamber 3.

Description

[Technical Field]

[0001] The present disclosure relates to a water softening device using ion exchange resins. [Background Art]

[0002] Currently, water softeners are widely used mainly in hard water regions for the purpose of removing hardness components from tap water, and such water softeners require regular salt replenishment work.

[0003] Furthermore, in order to solve the problem of work burden associated with salt replenishment and the problem in terms of performance that soft water cannot be obtained if salt replenishment is not properly performed, water softening technology that enables maintenance without using salt has been developed (for example, Patent Document 1).

[0004] The water softening system disclosed in Patent Document 1 has, as a basic configuration, a mixture of two types of resins: a weakly acidic cation exchange resin and a weakly basic anion exchange resin, and can obtain neutral soft water by using a bipolar membrane on the anode side of an electrode and a cation exchange resin membrane on the cathode side.

[0005] In the conventional technology, when a certain amount of hardness ions is adsorbed to the resin, regeneration of the resin is required. For example, in the regeneration step of Patent Document 1, a voltage is applied using electrodes to the BP membrane and the resin chamber present between the electrodes. An interface between a cation exchange resin and an anion exchange resin exists in the BP membrane or the ion exchange resin chamber. When a voltage is applied to this interface, water molecules are cleaved to generate hydrogen ions and hydroxide ions. The generated hydrogen ions can regenerate the weakly acidic cation exchange resin, and the generated hydroxide ions can regenerate the weakly basic anion exchange resin. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Unexamined Patent Publication No. 2016-163890 [Summary of the Invention] [Problems that the invention aims to solve]

[0007] However, in the technology described in Patent Document 1, hardness ions detached from the ion exchange resin are re-adsorbed onto the ion exchange resin, which tends to inhibit the reaction during resin regeneration. In other words, there was room for improvement in the regeneration efficiency of the ion exchange resin.

[0008] This disclosure was made to solve the above-mentioned problems and aims to provide a water softening device capable of improving the regeneration efficiency of ion exchange resin. [Means for solving the problem]

[0009] To solve the above problems, a water softening apparatus according to one aspect of the present invention comprises a water softening chamber that removes hardness components from water to be treated using a weakly acidic cation exchange resin, a neutralization chamber that neutralizes water to be treated using a weakly basic anion exchange resin, a first electrode pair that generates hydrogen ions to regenerate the weakly acidic cation exchange resin, a second electrode pair that generates hydroxide ions to regenerate the weakly basic anion exchange resin, and an ion concentration chamber provided between the water softening chamber and the neutralization chamber.

[0010] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, recording media, computer programs, etc., are also valid forms of this disclosure. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide a water softening device that can improve the regeneration efficiency of ion exchange resin. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a water softening device according to the first embodiment. [Figure 2] Figure 1 is a schematic diagram showing the regeneration operation of the water softening device. [Figure 3]This is a schematic diagram showing another example of a water softening device according to the first embodiment. [Figure 4] This is a schematic diagram showing a water softening device according to the second embodiment. [Figure 5] This is a schematic diagram showing a water softening device according to the third embodiment. [Figure 6] Figure 5 is a schematic top view showing the water softening device.

[0013] Hereinafter, embodiments for implementing this disclosure will be described with reference to the attached drawings. Each embodiment described below represents a preferred specific example of this disclosure. Therefore, the numerical values, shapes, materials, components, arrangement and connection configurations of components, as well as the steps (processes) and the order of steps shown in the following embodiments are examples and are not intended to limit this disclosure. Accordingly, among the components in the following embodiments, those components that are not described in the independent claims representing the highest-level concept of this disclosure will be described as arbitrary components. In addition, substantially identical components are denoted by the same reference numerals in each figure, and redundant explanations are omitted or simplified.

[0014] Furthermore, while terms including ordinal numbers such as "1st" and "2nd" are used to describe various components, these terms are used solely to distinguish one component from others, and do not limit the components themselves. When distinction is not necessary, ordinal numbers such as "1st" and "2nd" may be omitted.

[0015] First, let me explain the background to this disclosure. A water softening device is conceivable that uses a water softening resin that adsorbs hardness components such as magnesium ions and calcium ions and releases hydrogen ions into the water to soften it, and a neutralizing resin that adsorbs hydrogen ions and anions such as sulfate ions and carbonate ions and releases hydroxide ions into the water to neutralize them. If this device continues water softening operation for a certain period of time, the water softening resin will release most of its hydrogen ions and will no longer be able to soften the water. Therefore, it is important to regenerate the water softening resin by periodically supplying hydrogen ions to it. Similarly, the neutralizing resin will release most of its hydroxide ions and will no longer be able to neutralize the water, so it is important to regenerate the neutralizing resin as well.

[0016] To regenerate water softening resin and neutralizing resin, it is conceivable to generate hydrogen ions and hydroxide ions from electrodes, thereby simultaneously causing ion exchange and ion transfer. Specifically, by first applying current to each electrode, hydrogen ions are generated from the anode and hydroxide ions from the cathode through the electrolysis of water. The hydrogen ions from the anode are exchanged with hardness components adsorbed on the water softening resin, thereby regenerating the water softening resin. Similarly, the hydroxide ions from the cathode are exchanged with anions adsorbed on the neutralizing resin, thereby regenerating the neutralizing resin.

[0017] At this time, hydrogen ions generated from the anode and hardness components detached from the softening resin move due to the electric field and concentration gradient formed between the anode and cathode. Similarly, hydroxide ions generated from the cathode and anions detached from the neutralizing resin move due to the electric field and concentration gradient formed between the anode and cathode.

[0018] In this water softening system, it is conceivable that the amount of hydrogen ions and hydroxide ions available for regeneration decreases as hydroxide ions enter the water softening chamber and combine with hydrogen ions, and as hydrogen ions and hardness components enter the neutralization chamber and combine with hydroxide ions, thus reducing the regeneration efficiency.

[0019] In view of the above circumstances, the present inventors have completed the technology of the present disclosure. Hereinafter, the technology of the present disclosure will be described with reference to several embodiments.

[0020] [First Embodiment] Referring to FIG. 1 and FIG. 2, the configuration of a water softening apparatus 100 according to a first embodiment of the present disclosure will be described. FIG. 1 is a schematic diagram showing the water softening apparatus 100 according to the first embodiment. FIG. 2 is a schematic diagram showing a regeneration operation of the water softening apparatus 100.

[0021] The water softening apparatus 100 is an apparatus that generates neutral soft water from raw water containing hardness components supplied from the outside to an inflow port 15, and discharges the neutral soft water from an outflow port 16. The raw water refers to water introduced into the water softening apparatus 100 from a raw water supply pipe (not shown) described later (hereinafter referred to as "water to be treated W1"), and is, for example, well water or tap water. The raw water contains hardness components such as calcium ions and magnesium ions (hereinafter referred to as "hardness component C").

[0022] By performing a water softening operation of softening raw water using the water softening apparatus 100, neutral soft water with reduced hardness can be obtained from raw water with high hardness, and soft water can be used even in areas where the hardness of raw water is high. In addition, after performing the water softening operation for a certain period of time, the water softening apparatus 100 performs a regeneration operation to regenerate the ion exchange resin. The regeneration operation is started during time periods when soft water generation is not required, such as at night, ends after a predetermined period of time, for example, 4 to 8 hours, and then switches to the water softening operation.

[0023] The water softening apparatus 100 includes a housing 10, a water softening chamber 2, a neutralization chamber 3, a first electrode pair 4, a second electrode pair 5, an ion concentration chamber 6, a retention space 72, and a control unit 8. The housing 10 has a water passage chamber 14 through which the water to be treated W1 flows, a power supply chamber 13 that accommodates power supplies 11 and 12, an inflow port 15 provided on the upstream side of the water passage chamber 14, and an outflow port 16 provided on the downstream side of the water passage chamber 14. The water to be treated W1 is supplied to the inflow port 15 and discharged from the outflow port 16. A front space 71, the water softening chamber 2, the neutralization chamber 3, the ion concentration chamber 6, and the retention space 72 are provided in the water passage chamber 14.

[0024] A weakly acidic cation exchange resin 22 is held in the water softening chamber 2, and a weakly basic anion exchange resin 32 is held in the neutralization chamber 3. The first electrode pair 4 includes a first anode 41 provided in the water softening chamber 2 surrounded by the weakly acidic cation exchange resin 22, and a first cathode 42 provided in the ion concentration chamber 6. The second electrode pair 5 includes a second anode 51 provided in the ion concentration chamber 6, and a second cathode 52 provided in the neutralization chamber 3 surrounded by the weakly basic anion exchange resin 32. The first anode 41, first cathode 42, second anode 51, and second cathode 52 may be referred to as electrodes. No current is applied to each electrode during water softening operation. During regeneration, electrolytic current is applied from the positive electrode of power supply 11 to the first anode 41 and from the negative electrode to the first cathode 42, and electrolytic current is applied from the positive electrode of power supply 12 to the second anode 51 and from the negative electrode to the second cathode 52.

[0025] The water softening chamber 2 removes hardness component C from the water to be treated W1 using a weakly acidic cation exchange resin 22 located in the space between the permeable membranes 28 and 29 on the upstream and downstream sides. The neutralization chamber 3 neutralizes the water to be treated W1 using a weakly basic anion exchange resin 32 located in the space between the permeable membranes 38 and 39 on the upstream and downstream sides. The first electrode pair 4 generates hydrogen ions to regenerate the weakly acidic cation exchange resin 22. The second electrode pair 5 generates hydroxide ions to regenerate the weakly basic anion exchange resin 32. The ion concentration chamber 6 is a space located between the water softening chamber 2 and the neutralization chamber 3.

[0026] For example, the left-right thickness of the water softening chamber 2 and neutralization chamber 3 may be 50 mm to 500 mm, the vertical height of each chamber may be 200 mm to 600 mm, and the front-to-back thickness of each chamber may be 500 mm to 1500 mm. Also, the left-right thickness of the ion concentration chamber 6 may be 200 mm to 600 mm. Furthermore, the vertical dimension of each electrode in the first electrode pair 4 and the second electrode pair 5 is preferably 50% or more of the height dimension of the water softening chamber 2 and neutralization chamber 3. The design can be appropriately adjusted considering the balance between cost and regeneration efficiency.

[0027] The pre-treatment space 71, water softening chamber 2, ion concentration chamber 6, neutralization chamber 3, and retention space 72 are arranged in this order from upstream to downstream of the water to be treated W1. The pre-treatment space 71 is located upstream of the water softening chamber 2, and the retention space 72 is located downstream of the neutralization chamber 3. A drainage mechanism 17 is provided in the ion concentration chamber 6, and a drainage mechanism 18 is provided in the retention space 72.

[0028] The weakly acidic cation exchange resin 22 is an ion exchange resin having a carboxyl group, and for example, one having a methacrylic acid skeleton or one having an acrylic acid skeleton can be used. In this embodiment, a resin having an acrylic acid skeleton is used as the weakly acidic cation exchange resin 22. The weakly basic anion exchange resin 32 is an ion exchange resin having a primary amine, a tertiary amine, or a quaternary amine as a functional group. In this embodiment, a resin with a higher proportion of tertiary or primary amine than quaternary amine is used as the weakly basic anion exchange resin 32. The weakly acidic cation exchange resin 22 and the weakly basic anion exchange resin 32 in this example have a spherical shape as an example. In this case, a water passage for the water to be treated W1 can be secured.

[0029] The water softener 100 has a water softening operation that generates softened water and a regeneration operation that regenerates the ion exchange resin. The control unit 8 controls the execution of the water softening operation and the regeneration operation. The control unit 8 controls the on / off state and current value of the power supplies 11 and 12, controls the opening and closing of the inlet 15 and outlet 16, and controls the opening and closing of the drainage mechanisms 17 and 18. The control unit 8 can be implemented as hardware, such as a computer's CPU (Central Processing Unit), and as software, such as a computer program. Therefore, these functional blocks can be implemented in various forms by combining hardware and software.

[0030] Referring to Figure 1, the water softening operation of the water softener 100 will be explained. During the water softening operation, the drainage mechanisms 17 and 18 are closed, the outlet 16 is left open to allow water to pass through, and power is not supplied from the power supplies 11 and 12 to the electrodes 41, 42, 43, and 44. During the water softening operation, the water to be treated W1 supplied from the inlet 15 passes through the water softening chamber 2. At this time, the weakly acidic cation exchange resin 22 filling the water softening chamber 2 is exposed to the water to be treated W1, causing ion exchange between the hardness component C in the water to be treated W1 and the hydrogen ions contained in the weakly acidic cation exchange resin 22, which reduces the hardness component C in the water to be treated W1 and softens the water.

[0031] The hardness component C consists of calcium ions and magnesium ions. The treated water W1, which has been softened by this ion exchange, contains a large amount of hydrogen ions released from the weakly acidic cation exchange resin 22, and therefore becomes acidic soft water.

[0032] The treated water W1, which has become acidic soft water, passes through the neutralization chamber 3. At this time, the weakly basic anion exchange resin 32 that fills the neutralization chamber 3 is exposed to the acidic soft water W1, and hydrogen ions and anions (hereinafter referred to as "anion A") in the treated water W1 are adsorbed onto the weakly basic anion exchange resin 32, reducing the amount of anion A and hydrogen ions in the treated water W1, resulting in neutralized soft water.

[0033] Anion A is, for example, carbonate ions, sulfate ions, etc. The treated water W1, which has been neutralized and softened, is supplied via the outlet 16 to an external water intake (not shown), such as a faucet or shower.

[0034] Next, the regeneration operation of the water softener 100 will be explained with reference to Figure 2. During the regeneration operation, the drainage mechanisms 17 and 18 and the outlet 16 are closed to prevent water from passing through, and a predetermined amount of raw water to be used for regeneration is collected in the housing 10 from the inlet 15. Once the raw water has been collected, power is supplied to the electrodes 41, 42, 43, and 44 from the power supplies 11 and 12 to start electrolysis.

[0035] In this electrolysis, ion exchange occurs in the water softening chamber 2 between hydrogen ions generated from the first anode 41 and hardness component C adsorbed on the weakly acidic cation exchange resin 22. This regenerates the weakly acidic cation exchange resin 22 and releases hardness component C into the water. In the neutralization chamber 3, ion exchange occurs between hydroxide ions generated at the second cathode 52 and anion A adsorbed on the weakly basic anion exchange resin 32. This regenerates the weakly basic anion exchange resin 32 and releases anion A into the water.

[0036] The hardness component C released into the water softening chamber 2 moves toward the first cathode 42 due to the electric field between the first anode 41 and the first cathode 42. Similarly, the anion A released in the neutralization chamber 3 moves toward the second anode 51 due to the electric field between the second cathode 52 and the second anode 51. The hardness component C and anion A combine in the ion concentration chamber 6, precipitating as solid matter S such as calcium carbonate. After a predetermined time, the power is turned off, and the drainage mechanisms 17 and 18 are opened to discharge the solid matter S and water. As a result, each ion exchange resin is regenerated. Note that if the ion concentration chamber 6 is kept electrically neutral, solid matter S such as calcium carbonate is less likely to precipitate. On the other hand, if the ion concentration chamber 6 becomes alkaline, solid matter S is more likely to precipitate. The regeneration operation is started, for example, at night when there is no need to generate softened water, and ends after a predetermined time, switching to water softening operation. For example, the prescribed duration for the regeneration operation may be 4 to 8 hours.

[0037] In Figure 2, the first cathode 42 may be positioned upstream of the second anode 51. Furthermore, multiple electrodes may be arranged at predetermined intervals in the direction towards the back of the paper. The design can be appropriately adjusted considering the balance between cost and regeneration efficiency. Additionally, during regeneration, the weakly acidic cation exchange resin 22 may be more difficult to regenerate than the weakly basic anion exchange resin 32; therefore, the current applied to the first electrode pair 4 during regeneration may be higher than the current applied to the second electrode pair 5.

[0038] During regeneration operation, it is desirable to suppress the re-adsorption of hardness component C onto the weakly acidic cation exchange resin 22. Therefore, in the water softening device 100 of this embodiment, the first electrode pair 4 comprises a first anode 41 surrounded by the weakly acidic cation exchange resin 22 and a first cathode 42 provided in the ion concentration chamber 6. In this case, during regeneration operation, the hardness component C that has been detached from the weakly acidic cation exchange resin 22 in the water softening chamber 2 is guided to the first cathode 42 in the ion concentration chamber 6 by the electric field generated between the first anode 41 and the first cathode 42.

[0039] This makes it less likely for hardness component C to remain in the water softening chamber 2, and suppresses its re-adsorption to the weakly acidic cation exchange resin 22. Furthermore, it suppresses hardness component C from entering the neutralization chamber 3 and binding with hydroxide ions. In other words, these factors improve the regeneration efficiency of the ion exchange resin.

[0040] Furthermore, the statement that electrodes such as the first anode 41 are surrounded by ion exchange resin includes both the state in which the electrode surface is in contact with the surface of the ion exchange resin from its entire circumference from top to bottom, and the state in which the electrode surface is in contact with the surface of the ion exchange resin only partially. The same applies to other electrodes below.

[0041] During regeneration operation, it is desirable to suppress the re-adsorption of desorbed anion A onto the weakly basic anion exchange resin 32. Therefore, in the water softening device 100 of this embodiment, the second electrode pair 5 comprises a second anode 51 provided in the ion concentration chamber 6 and a second cathode 52 provided surrounded by the weakly basic anion exchange resin 32. In this case, during regeneration operation, anion A desorbed from the weakly basic anion exchange resin 32 in the neutralization chamber 3 is guided to the second anode 51 in the ion concentration chamber 6 by the electric field generated between the second cathode 52 and the second anode 51.

[0042] This makes it less likely for anion A to remain in the neutralization chamber 3, and prevents it from being re-adsorbed onto the weakly basic anion exchange resin 32. It also prevents anion A from entering the water softening chamber 2 and binding with hydrogen ions. In other words, these improvements improve the regeneration efficiency of the ion exchange resin. Specifically, hardness component C and anion A, which are introduced into the ion concentration chamber 6, bind within the ion concentration chamber 6, making it less likely for these ionic components to enter the water softening chamber 2 or the neutralization chamber 3. This prevents the disappearance of hydrogen ions and hydroxide ions. In other words, these improvements improve the regeneration efficiency of the ion exchange resin.

[0043] Referring to Figure 3, another example of the water softener 100 will be described. Figure 3 is a schematic diagram showing another example of the water softener 100 of the first embodiment. The example in Figure 3 differs from the example in Figure 1 in that the arrangement of the second cathode 52 is different, but the other configurations are the same, so redundant explanations will be omitted and the differences will be explained in detail.

[0044] It is desirable to suppress the re-adsorption of the desorbed anion A onto the weakly basic anion exchange resin 32. Therefore, another example of the water softening device 100 of the embodiment has a drainage mechanism 17 and a retention space 72 provided with a neutralization chamber 3 in between it and the ion concentration chamber 6, and the second electrode pair 5 comprises a second anode 51 provided in the ion concentration chamber 6 and a second cathode 52 provided in the retention space 72. In this case, during regeneration operation, the anion A desorbed from the weakly basic anion exchange resin 32 in the neutralization chamber 3 is guided to the second anode 51 of the ion concentration chamber 6 by the electric field generated between the second cathode 52 and the second anode 51.

[0045] This makes it less likely for anion A to remain in the neutralization chamber 3, and prevents it from being re-adsorbed onto the weakly basic anion exchange resin 32. Furthermore, it prevents anion A from entering the water softening chamber 2 and binding with hydrogen ions. In other words, these factors improve the regeneration efficiency of the ion exchange resin.

[0046] In other words, the hardness component C and anion A introduced into the ion concentration chamber 6 bind within the chamber, making it difficult for these ionic components to penetrate the water softening chamber 2 or the neutralization chamber 3. This suppresses the disappearance of hydrogen ions and hydroxide ions. In other words, this improves the regeneration efficiency of the ion exchange resin.

[0047] In addition, since the second cathode 52 is not in contact with the weakly basic anion exchange resin 32, the risk of the weakly basic anions burning and degrading when current is applied to the second cathode 52 can be reduced. Furthermore, by deliberately generating hydroxide ions in the retention space 72 where hardness component C is present, precipitates derived from hardness component C can be deposited in the retention space 72 and made easier to discharge, thereby suppressing precipitation in the water softening chamber 2 and neutralization chamber 3. Moreover, electrodes can be easily replaced compared to cases where the electrodes are surrounded by ion exchange resin.

[0048] It is desirable to suppress the re-adsorption of the desorbed hardness component C onto the weakly acidic cation exchange resin 22. Therefore, in the water softening device 100 of the embodiment, as shown in Figures 2 and 3, the first cathode 42 is provided between the second anode 51 and the second cathode 52. In this case, as described above, during regeneration operation, the hardness component C desorbed from the weakly acidic cation exchange resin 22 in the water softening chamber 2 is guided toward the first cathode 42 and therefore accumulates in the vicinity of the first cathode 42.

[0049] Meanwhile, anion A, which has been released from the weakly basic anion exchange resin 32, is guided from the second cathode 52 toward the second anode 51. At this time, the first cathode 42, where hardness component C is accumulated, is positioned between the second cathode 52 and the second anode 51, allowing for efficient binding of hardness component C and anion A within the ion concentration chamber 6. This prevents hardness component C and anion A from entering the water softening chamber 2 or the neutralization chamber 3, thereby improving regeneration efficiency.

[0050] It is desirable that the hardness component C and anion A collected in the ion concentration chamber 6 be directly discharged. Therefore, in the water softening device 100 of this embodiment, as shown in Figures 2 and 3, the ion concentration chamber 6 has a drainage mechanism 17 for draining water from inside the ion concentration chamber 6. In this case, when regeneration is complete, the hardness component C and anion A collected in the ion concentration chamber 6 can be drained from the drainage mechanism 17 without going through the water softening chamber 2 or the neutralization chamber 3. This suppresses the re-adsorption of hardness component C or anion A onto the respective ion exchange resins. In other words, the regeneration efficiency can be improved.

[0051] The operation and effects of the water softening device 100 according to the first embodiment will now be explained. With the water softening device 100, by providing an ion concentration chamber 6, hardness component C is less likely to penetrate into the neutralization chamber 3, and therefore, the hydroxide ions necessary for regeneration can be suppressed from binding with hardness component C in the neutralization chamber 3. Similarly, anion A is less likely to penetrate into the water softening chamber 2, and therefore, the hydrogen ions necessary for regeneration can be suppressed from binding with anion A in the water softening chamber 2. In other words, these measures can improve the regeneration efficiency of the ion exchange resin.

[0052] [Second Embodiment] The configuration of the water softener 200 according to the second embodiment of this disclosure will be described with reference to Figure 4. Figure 4 is a schematic diagram showing the water softener 200 according to the second embodiment. In the example in Figure 4, the same reference numerals are used for components that are substantially the same as those in the water softener 100 of the first embodiment, and redundant explanations are omitted or simplified.

[0053] The description of the first embodiment showed a water softening device having a single water softening chamber 2, an ion concentration chamber 6, and a neutralization chamber 3, but the disclosure is not limited thereto. The water softening device 200 of the second embodiment is constructed by stacking multiple water softening units 9, each having a water softening chamber 2, an ion concentration chamber 6, and a neutralization chamber 3. In this case, the water softening device 200 can be efficiently formed by stacking multiple water softening units 9. In other words, even if a single water softening unit 9 cannot sufficiently soften the water, hardness components can be removed more efficiently by connecting multiple water softening units 9 in a cascade.

[0054] In the example shown in Figure 4, the water softening device 200 has three water softening units 9 stacked from upstream to downstream, and performs water softening and neutralization treatment in order from upstream. When distinguishing between the water softening units 9, they are referred to as water softening units 91, 92, and 93. Water softening unit 91 softens and neutralizes the water to be treated W1 supplied from the inlet 15 and supplies it to the downstream water softening unit 92. Water softening unit 92 softens and neutralizes the water to be treated W1 supplied from water softening unit 91 and supplies it to the downstream water softening unit 93. Water softening unit 93 softens and neutralizes the water to be treated W1 supplied from water softening unit 92 and discharges it from the outlet 16 via the downstream retention space 72.

[0055] In the water softener 200, water softening and regeneration operations are performed in the same manner as in the water softener 100 of the first embodiment. The housing 10 of the water softener 200 has a drainage chamber 20 in addition to a water passage chamber 14 and a power supply chamber 13. The drainage chamber 20 is configured to receive wastewater from the drainage mechanisms 17 provided in each ion concentration chamber 6. During water softening and regeneration operations, each drainage mechanism 17 is closed, and no wastewater flows into the drainage chamber 20. After the regeneration operation is completed, each drainage mechanism 17 is opened, and wastewater flows into the drainage chamber 20. The wastewater that flows into the drainage chamber 20 is discharged to the outside through a drain port 21 provided in the drainage chamber 20.

[0056] During regeneration operation, the current applied to each electrode pair may be set higher on the upstream side near the inlet 15 and lower on the downstream side near the outlet 16. The upstream water softening unit 91 softens water W1 with a higher content of hardness component C than the downstream water softening units 92 and 93, resulting in greater consumption of the weakly acidic cation exchange resin 22. Therefore, by setting the current applied to electrode pairs 4 and 5 of the water softening unit 91 higher than that applied to the downstream electrode pair, regeneration efficiency can be improved on the upstream side. Furthermore, by setting the current applied to electrode pairs 4 and 5 of the water softening unit 93 lower than that applied to the upstream electrode pair, power consumption on the downstream side can be reduced and regeneration efficiency can be improved.

[0057] For example, the thickness of the layer between each water softening unit 9 in the left-right direction may be 500 mm to 1500 mm.

[0058] The number of water softening units 9 in the water softening device 200 is not limited to 3, but may be 2 or 4 or more. The water softening device 200 according to the second embodiment provides the same functions and effects as the water softening device 100 of the first embodiment, and in addition, the regeneration efficiency is further improved by stacking multiple water softening units 9.

[0059] [Third Embodiment] The configuration of the water softener 300 according to the third embodiment of this disclosure will be described with reference to Figures 5 and 6. Figure 5 is a schematic diagram showing the water softener 300 according to the third embodiment. Figure 6 is a schematic top view of the water softener 300, showing a cross-section along line DD in Figure 5. In Figures 5 and 6, components that are substantially the same as those in the water softener 100 of the first embodiment are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0060] The water softening device 300 of the third embodiment comprises a cylindrical housing 90 that encloses a water softening chamber 2, an ion concentration chamber 6, a neutralization chamber 3, a first electrode pair 4, and a second electrode pair 5. When viewed from above, the water softening chamber 2, the ion concentration chamber 6, and the neutralization chamber 3 are arranged in that order from the center of the circle toward the outer circumference.

[0061] The water softener 300 has a cylindrical shape overall, with an inlet 15 at one end and an outlet 16 at the other end. The direction parallel to the central axis X of the water softener 300 is called the X direction. In the water softener 300, the water to be treated W1 that flows in from the inlet 15 in the X direction is flowed radially, performing water softening and neutralization treatments, and then discharged from the outlet 16 in the X direction. In this explanation, the side with the outlet 16 relative to the inlet 15 is called "up," and the opposite side is called "down." This directional notation does not restrict the orientation in which the water softener 300 is used, and the water softener 300 can be used in any orientation.

[0062] The housing 90 has a cylindrical outer casing 97, a bottom surface 96 that closes the lower end of the outer casing 97, and a top surface 95 that closes the upper end of the outer casing 97, and functions as the outer shell of each component of the water softening device 300. An air vent valve 98 for releasing air from inside the housing 90 is provided on the top surface 95 of the housing 90.

[0063] The inlet 15 has a cylindrical shape centered on the central axis X and extends vertically through the center of the bottom portion 96. The pre-space 71 has a cylindrical shape centered on the central axis X and causes the water to be treated W1 flowing in from the inlet 15 to flow out radially outwards.

[0064] The inner diaphragm 28 has a cylindrical shape that surrounds the pre-space 71. The water softening chamber 2 is a cylindrical space that surrounds the inner diaphragm 28 and holds a weakly acidic cation exchange resin 22. The outer diaphragm 29 has a cylindrical shape that surrounds the water softening chamber 2. The ion concentration chamber 6 is a cylindrical space that surrounds the outer diaphragm 29. The inner diaphragm 38 has a cylindrical shape that surrounds the ion concentration chamber 6. The neutralization chamber 3 is a cylindrical space that surrounds the inner diaphragm 38 and holds a weakly basic anion exchange resin 32. The outer diaphragm 39 has a cylindrical shape that surrounds the neutralization chamber 3.

[0065] The retention space 72 is a cylindrical space surrounding the outer diaphragm 39. The top surfaces of the pre-retaining space 71, inner diaphragm 28, water softening chamber 2, outer diaphragm 29, ion concentration chamber 6, inner diaphragm 38, neutralization chamber 3, and outer diaphragm 39 are in contact with a non-permeable disc-shaped lid member 94, and their bottom surfaces are in contact with the bottom portion 96 of the housing 90. The upper space 74 is a disc-shaped space between the lid member 94 and the top portion 95, which collects the water to be treated W1 that flows radially into the retention space 72 and guides it to the outlet 16.

[0066] The outlet 16 has a cylindrical shape centered on the central axis X and extends vertically through the center of the top surface 95. The outlet 16 discharges the treated water W1 collected in the upper space 74 to the outside from above. The first electrode pair 4 includes two first anodes 41 provided in the water softening chamber 2 surrounded by a weakly acidic cation exchange resin 22, and two first cathodes 42 provided in the ion concentration chamber 6. The first electrode pair 4 is connected to the power supply 11, and a predetermined current is applied from the power supply 11 during regeneration operation. The second electrode pair 5 includes two second cathodes 52 provided in the neutralization chamber 3 surrounded by a weakly basic anion exchange resin 32, and two second anodes 51 provided in the ion concentration chamber 6. The second electrode pair 5 is connected to the power supply 12, and a predetermined current is applied from the power supply 12 during regeneration operation. In the example of Figure 6, the electrodes of the first electrode pair 4 and the second electrode pair 5 are arranged linearly in the radial direction. The first cathode 42 is positioned radially outward from the second anode 51.

[0067] The number of electrodes is not limited to two; it may be one or three or more.

[0068] The pre-space 71 in the first and second embodiments may be equipped with a drainage mechanism for draining water containing hardness components from the pre-space 71 to the outside. With such a configuration, the water drained from the pre-space 71 is less likely to pass through the water softening chamber 2. This makes it possible to suppress the re-adsorption of hardness components onto the weakly acidic cation exchange resin 22, thereby improving the regeneration efficiency.

[0069] In the third embodiment, the water softening chamber 2, ion concentration chamber 6, and neutralization chamber 3 perform the same functions as the water softening chamber 2, ion concentration chamber 6, and neutralization chamber 3 of the first embodiment for the water to be treated W1 that flows radially from the center.

[0070] In the water softening device 300, water softening and regeneration operations are performed in the same manner as in the water softening device 100 of the first embodiment. Although not shown in the figures, a drainage mechanism for wastewater is provided in the ion concentration chamber 6.

[0071] The water softener 300 according to the third embodiment provides the same functions and effects as the water softener 100 of the first embodiment, and in addition, the water softener 100 can be easily formed by providing a housing 90.

[0072] The above is a description of the embodiment.

[0073] One aspect of this disclosure is as follows: (Item 1) A water softening chamber (2) that removes hardness components from the water to be treated using a weakly acidic cation exchange resin (22), A neutralization chamber (3) for neutralizing the water to be treated with a weakly basic anion exchange resin (32), A first electrode pair (4) that generates hydrogen ions in order to regenerate the weakly acidic cation exchange resin (22), A second electrode pair (5) that generates hydroxide ions in order to regenerate the weakly basic anion exchange resin (32), A water softening apparatus (100) comprising an ion concentration chamber (6) provided between the water softening chamber (2) and the neutralization chamber (3).

[0074] (Item 2) The water softening apparatus (100) according to item 1, wherein the first electrode pair (4) comprises a first anode (41) provided surrounded by the weakly acidic cation exchange resin (22) and a first cathode (42) provided in the ion concentration chamber (6).

[0075] (Item 3) The water softening apparatus (100) according to item 2 comprises a second anode (51) provided in the ion concentration chamber (6) and a second cathode (52) provided surrounded by the weakly basic anion exchange resin (32).

[0076] (Item 4) It has a drainage mechanism (18) and a retention space (72) provided between the ion concentration chamber (6) and the neutralization chamber (3), The second electrode pair (5) comprises a second anode (51) provided in the ion concentration chamber (6) and a second cathode (52) provided in the retention space (72). The water softening device (100) described in item 2.

[0077] (Item 5) The first cathode (42) is provided between the second anode (51) and the second cathode (52) in the water softening device (100) described in item 3 or 4.

[0078] (Item 6) The ion concentration chamber (6) is a water softening device (100) according to item 3 or 4, having a drainage mechanism (17) for draining water from inside the ion concentration chamber (6).

[0079] (Item 7) A water softening device (100) according to item 3 or 4, comprising a plurality of stacked water softening units (9) each having a water softening chamber (2), an ion concentration chamber (6), and a neutralization chamber (3).

[0080] (Item 8) The device comprises a cylindrical housing (90) that encloses the water softening chamber (2), the ion concentration chamber (6), and the neutralization chamber (3), A water softening apparatus (300) according to item 3 or 4, wherein, when viewed from above, the water softening chamber (2), the ion concentration chamber (6), and the neutralization chamber (3) are arranged in that order from the center of the circle toward the outer circumference of the circle.

[0081] The present disclosure has been described above based on embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various alternatives are possible for each component or combination of each processing process, and that such alternatives are also within the scope of the present disclosure. [Industrial applicability]

[0082] This disclosure can be used as a water softening device installed in homes and other locations to remove hardness components from tap water. [Explanation of symbols]

[0083] 2 Water softening chamber, 3 Neutralization chamber, 4 First electrode pair, 5 Second electrode pair, 6 Ion concentration chamber, 8 Control unit, 9 Water softening unit, 10 Housing, 11,12 Power supply, 13 Power supply chamber, 14 Water passage chamber, 15 Inlet, 16 Outlet, 17,18 Drainage mechanism, 20 Drainage chamber, 21 Drain outlet, 22 Weakly acidic cation exchange resin, 28 Inner diaphragm, 29 Outer diaphragm, 32 Weakly basic anion exchange resin, 38 Inner diaphragm, 39 Outer diaphragm, 41 First anode, 42 First cathode, 51 Second anode, 52 Second cathode, 71 Pre-space, 72 Retention space, 74 Upper space, 90 Housing, 91,92,93 Water softening unit 94 Lid member, 95 Top surface, 96 Bottom surface, 97 Outer cylinder, 98 Air vent valve, 100, 200, 300 Water softening device, W1 Water to be treated.

Claims

1. A water softening chamber that removes hardness components from the water to be treated using a weakly acidic cation exchange resin, A neutralization chamber for neutralizing the water to be treated with a weakly basic anion exchange resin, A first electrode pair that generates hydrogen ions in order to regenerate the weakly acidic cation exchange resin, A second electrode pair that generates hydroxide ions in order to regenerate the weakly basic anion exchange resin, A water softening apparatus comprising an ion concentration chamber provided between the water softening chamber and the neutralization chamber.

2. The water softening apparatus according to claim 1, wherein the first electrode pair comprises a first anode provided surrounded by the weakly acidic cation exchange resin and a first cathode provided in the ion concentration chamber.

3. The water softening apparatus according to claim 2, wherein the second electrode pair comprises a second anode provided in the ion concentration chamber and a second cathode provided surrounded by the weakly basic anion exchange resin.

4. It has a drainage mechanism and is equipped with a retention space that is provided between the ion concentration chamber and the neutralization chamber, The water softening apparatus according to claim 2, wherein the second electrode pair comprises a second anode provided in the ion concentration chamber and a second cathode provided in the retention space.

5. The water softening apparatus according to claim 3 or 4, wherein the first cathode is provided between the second anode and the second cathode.

6. The water softening apparatus according to claim 3 or 4, wherein the ion concentration chamber has a drainage mechanism for draining water from the inside of the ion concentration chamber.

7. The water softening apparatus according to claim 3 or 4, comprising a plurality of stacked water softening units, each having a water softening chamber, an ion concentration chamber, and a neutralization chamber.

8. The system comprises a cylindrical housing that encloses the water softening chamber, the ion concentration chamber, and the neutralization chamber, The water softening apparatus according to claim 3 or 4, wherein, when viewed from above, the water softening chamber, the ion concentration chamber, and the neutralization chamber are arranged in that order from the center of the circle toward the outer circumference of the circle.

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