Water softening device

Abstract

A water softening device (100) is provided with: a water softening chamber (201) having a weakly acidic cation exchange resin (101) and generating soft water from raw water containing a hard component; a neutralization chamber (202) that has a weakly alkaline anion exchange resin (102) and neutralizes the soft water; a diaphragm that partitions between the water softening chamber (201) and the neutralization chamber (202) such that soft water can pass therethrough; a first electrode (103) that functions as an anode during regeneration of the weakly acidic cation exchange resin (101); and a second electrode (104) that functions as a cathode during regeneration of the weakly alkaline anion exchange resin (102). The first electrode (103) is provided in the water softening chamber (201) so as to be surrounded by a weakly acidic cation exchange resin (101), and the second electrode (104) is provided in the neutralization chamber (202) so as to be surrounded by a weakly alkaline anion exchange resin (102).

Description

Technical Field

[0001] This disclosure relates to a water softening device that utilizes an ion exchange resin. Background Technology

[0002] Currently, water softeners are widely used, especially in areas with hard water, to remove hardness from tap water. These water softeners require regular salt replenishment.

[0003] In addition, in order to solve the problem of the workload associated with salt replenishment and the performance problem of not being able to obtain soft water without proper salt replenishment, a water softening technology that can be maintained without the use of salt has been developed (see Patent Document 1).

[0004] In the soft water system disclosed in Patent Document 1, as a basic structure, two resins, a weakly acidic cation exchange resin and a weakly basic anion exchange resin, are mixed together. A bipolar membrane (a membrane formed by bonding a cation exchange resin membrane and an anion exchange resin membrane: hereinafter referred to as a BP membrane) is used on the anode side of a pair of electrodes, and a cation exchange resin membrane is used on the cathode side, thereby obtaining neutral soft water.

[0005] Furthermore, in this prior art, if a certain amount of hardness ions are adsorbed onto the resin, the resin needs to be regenerated. For example, in the regeneration process of Patent Document 1, an electrode is used to apply a voltage to the BP membrane and resin chamber located between the electrodes. An interface between cation exchange resin and anion exchange resin exists in the BP membrane or ion exchange resin chamber. If a voltage is applied to this interface, water molecules dissociate to generate H+. + and OH - The generated H can be used to... + Regenerating a weakly acidic cation exchange resin allows the generated OH groups to pass through. - The weakly basic anion exchange resin is regenerated.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 6444939 Summary of the Invention

[0009] However, in the technology described in Patent Document 1, the hardness ions desorbed from the ion exchange resin are re-adsorbed onto the ion exchange resin, which can easily hinder the reaction during resin regeneration. Therefore, in order to remove the desorbed hardness ions, regeneration needs to be performed while water is flowing through it. Due to this water flow operation, there is a problem that the amount of wastewater discharged during resin regeneration increases.

[0010] This disclosure was made in view of the problems existing in the prior art. This disclosure provides a water softening apparatus capable of suppressing drainage during regeneration and enabling efficient regeneration of the resin.

[0011] The water softening apparatus disclosed herein comprises: a water softening chamber having a weakly acidic cation exchange resin for generating soft water from raw water containing hardness components; a neutralization chamber having a weakly basic anion exchange resin for neutralizing the soft water; a diaphragm separating the water softening chamber and the neutralization chamber in a manner allowing soft water to pass through; a first electrode that functions as an anode during the regeneration of the weakly acidic cation exchange resin; and a second electrode that functions as a cathode during the regeneration of the weakly basic anion exchange resin. The first electrode is disposed within the water softening chamber surrounded by the weakly acidic cation exchange resin, and the second electrode is disposed within the neutralization chamber surrounded by the weakly basic anion exchange resin.

[0012] According to this disclosure, a water softening apparatus is provided that can suppress drainage during regeneration and enable efficient regeneration of resin. Attached Figure Description

[0013] Figure 1 This is a perspective view of the water softening apparatus according to Embodiment 1 of this disclosure.

[0014] Figure 2 This is a cross-sectional view of the water softening device.

[0015] Figure 3 It is a diagram containing formulas that represent the principle of the water softening device.

[0016] Figure 4 This is a graph showing the hardness of the soft water during the water softening process before and after regeneration in Example 1.

[0017] Figure 5 This is a graph showing the pH changes over time in the water softening and neutralization chambers during the regeneration process of Example 1.

[0018] Figure 6 This is a graph showing the change over time in the molar number of each ion during the regeneration of Example 1.

[0019] Figure 7 This is a schematic diagram of a water softening apparatus according to Embodiment 2 of this disclosure.

[0020] Figure 8 This is a perspective view of the water softening device in Embodiment 2.

[0021] Figure 9 This is a cross-sectional view of the water softening device in Embodiment 2.

[0022] Figure 10It is a diagram containing formulas that represent the principle of the water softening device of Embodiment 2.

[0023] Figure 11 This is a graph showing the change in the proportion of hydrogen ions consumed by the weakly acidic cation exchange resin over time during the regeneration process.

[0024] Figure 12 This is a schematic diagram of the water softening device in Embodiment 4.

[0025] Figure 13 This is a schematic diagram of the water softening device in Embodiment 5.

[0026] Figure 14 This is a schematic diagram of the water softening device in Embodiment 6.

[0027] Figure 15 This is a schematic diagram of the water softening device in Embodiment 7.

[0028] Figure 16 This is a schematic diagram of a water softening apparatus according to Embodiment 8 of this disclosure.

[0029] Figure 17 This is a perspective view of the water softening device in Embodiment 8.

[0030] Figure 18 This is a cross-sectional view of the water softening device in Embodiment 8.

[0031] Figure 19 It is a diagram containing formulas that represent the principle of the water softening device of embodiment 8.

[0032] Figure 20 This is a graph showing the change in the proportion of hydrogen ions consumed by the weakly acidic cation exchange resin over time during the regeneration process.

[0033] Figure 21 This is a perspective view of a water softening device according to an example of Embodiment 8.

[0034] Figure 22 This is a graph showing the relationship between drainage volume and hardness one hour after the start of regeneration, according to an example of Embodiment 8.

[0035] Figure 23 This is a schematic diagram of a water softening apparatus according to Embodiment 9 of this disclosure.

[0036] Figure 24 This is a perspective view of the water softening device in Embodiment 9.

[0037] Figure 25 This is a cross-sectional view of the water softening device in Embodiment 9.

[0038] Figure 26 This illustrates the water softening device of embodiment 9. Figure 25 The cross-sectional view of section A-A' in the diagram.

[0039] Figure 27 It is a diagram containing formulas that represent the principle of the water softening device of embodiment 9.

[0040] Figure 28 This is a graph showing the change in the proportion of hydrogen ions consumed by the weakly acidic cation exchange resin over time during the regeneration process. Detailed Implementation

[0041] The embodiments of this disclosure will now be described with reference to the accompanying drawings. Furthermore, the following embodiments are merely examples embodying this disclosure and are not intended to limit the technical scope of this disclosure. Additionally, the figures described in each embodiment are schematic diagrams, and the ratios of the size and thickness of the constituent elements in each figure may not necessarily reflect actual dimensional ratios.

[0042] (Implementation Method 1)

[0043] Reference Figure 1 and Figure 2 The water softening apparatus 100 according to Embodiment 1 of this disclosure will be described.

[0044] Figure 1 This is a perspective view showing the structure of the water softening apparatus 100 according to Embodiment 1 of this disclosure. Figure 2 This is a cross-sectional view showing the structure of the water softening apparatus 100 according to Embodiment 1 of this disclosure. Furthermore, in Figure 1 and Figure 2 The various elements of a water softening device 100 are conceptually shown in the diagram. Additionally, in... Figure 1 In this description, the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 are omitted.

[0045] The water softening device 100 is a device that generates neutral soft water from raw water containing hardness components supplied from the outside. Furthermore, the raw water refers to the water (the water to be treated) introduced into the water softening device 100 from the water inlet 107 (described later), such as well water or tap water. The raw water contains hardness components (calcium ions or magnesium ions).

[0046] By using the water softening device 100 to perform a water softening process that softens the raw water, it is possible to obtain neutral soft water with reduced hardness from raw water with high hardness, and even in areas where the raw water has high hardness, soft water can be used.

[0047] Furthermore, after a certain period of water softening, the water softening device 100 performs a regeneration process, as described later, to regenerate the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102. Details regarding the water softening and regeneration processes will be described later.

[0048] Specifically, such as Figure 1 As shown, the water softening device 100 includes a housing 203, a water inlet 111, a water guide 107, a water softening chamber 201, a neutralization chamber 202, a water delivery section 108, and a water delivery outlet 110.

[0049] The outer shell 203 is a hollow cylindrical component. Within its hollow space, from the side near the central axis I that connects the upper and lower surfaces of the outer shell 203 towards the outer periphery, there are sequentially a water guiding section 107, a water softening chamber 201, a neutralization chamber 202, and a water delivery section 108.

[0050] A water guide inlet 111 is provided at the center of the lower surface of the outer casing 203, i.e., on the central axis I. A water delivery outlet 110 is provided at the center of the upper surface of the outer casing 203, i.e., on the central axis I. The central axis I of the outer casing 203 is aligned with the central axes of the water guide 107, the water softening chamber 201, the neutralization chamber 202, and the water delivery section 108.

[0051] The softening of raw water and the regeneration of ion exchange resin are carried out inside the outer shell 203.

[0052] The water guide inlet 111 is located on the bottom surface of the housing 203 and is used to supply raw water to the water guide section 107. The central axis of the water guide inlet 111 is aligned with the central axis I of the housing 203.

[0053] The water guide section 107 is a cylindrical component that connects to the water guide section inlet 111 at its lower end. The water guide section 107 guides raw water into the water softening device 100 to supply it to the water softening chamber 201. As the water guide section 107, pipes or other pipes with internal space can be used.

[0054] The water guiding section 107 is configured to ensure that the raw water introduced into the water softening device 100 flows evenly to the water softening chamber 201 and the neutralization chamber 202. Specifically, the water guiding section 107 is located in the center of the outer casing 203, and the outer periphery of the water guiding section 107 is in contact with the water softening chamber 201. In other words, the water guiding section 107 is located on the central axis I.

[0055] Furthermore, the water guiding section 107 extends from the lower part of the water softening chamber 201 and the neutralization chamber 202 to the upper part, or more precisely, from the lower end to the upper end. The length of the portion of the water guiding section 107 that supplies raw water to the water softening chamber 201 and the neutralization chamber 202 is equal to the height of the water softening chamber 201 and the neutralization chamber 202.

[0056] The water guiding section 107 has multiple holes on its side surface through which raw water is fed from the central axis I of the outer casing 203 toward the outer periphery, i.e., toward the water softening chamber 201. Preferably, the multiple holes are evenly arranged circumferentially on the side surface of the water guiding section 107. With this structure, the raw water introduced into the device can flow evenly to the water softening chamber 201 and the neutralization chamber 202. Therefore, raw water is supplied without leakage to the particles of the weakly acidic cation exchange resin 101 filled in the water softening chamber 201 and the particles of the weakly basic anion exchange resin 102 filled in the neutralization chamber 202. Thus, the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 can be utilized efficiently overall.

[0057] The water guiding section 107 has multiple pores on its side surface that are smaller than the particle size of the weakly acidic cation exchange resin. The lower limit of the particle size of the weakly acidic cation exchange resin is about 0.3 mm, therefore the diameter of the pores provided on the surface of the water guiding section 107 is smaller than that. As a result, water permeability is not hindered, and the ion exchange resin is prevented from flowing out of the water softening chamber 201.

[0058] The water softening chamber 201 is disposed within the outer casing 203 on the outer periphery of the water guiding section 107 relative to the central axis I of the outer casing 203. It is a cylindrical space containing a weakly acidic cation exchange resin 101. The central axis of the water softening chamber 201 coincides with the central axis I of the outer casing 203. The water softening chamber 201 is connected to the water guiding section 107 on its inner cylindrical side and to the inner peripheral diaphragm 105 on its outer side. In other words, the water softening chamber 201 surrounds the water guiding section 107 and is surrounded by the inner peripheral diaphragm 105.

[0059] The upper surface of the water softening chamber 201 is in contact with the cover 112, configured to prevent water from flowing out. This is to prevent water from flowing out from the upper surface of the water softening chamber 201 and to allow water to bypass the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 during the water softening process. Further details regarding the cover 112 will be described later.

[0060] A weakly acidic cation exchange resin 101 is filled in the water softening chamber 201. This weakly acidic cation exchange resin 101 generates soft water from raw water containing hardness components. Specifically, in the water softening chamber 201, the hardness components contained in the raw water are adsorbed onto the weakly acidic cation exchange resin 101, generating soft water containing protons released in place of the hardness components.

[0061] The weak acid cation exchange resin 101 is an ion exchange resin having carboxyl groups. For example, a resin having a methacrylic acid backbone or a resin having an acrylic acid backbone can be used. In this embodiment, a resin having an acrylic acid backbone is used as the weak acid cation exchange resin 101.

[0062] The volume of the weakly acidic cation exchange resin 101 filling the water softening chamber 201 is smaller than the volume of the weakly basic anion exchange resin 102 filling the neutralization chamber 202 (described later). This is because the water softening chamber 201 is located on the inner periphery of the neutralization chamber 202, and its volume is smaller than that of the neutralization chamber 202.

[0063] A first electrode 103 is provided in the water softening chamber 201.

[0064] The first electrode 103 is an electrode that is not energized during water softening but functions as an anode during the regeneration of the weakly acidic cation exchange resin 101. The first electrode 103 is surrounded by the weakly acidic cation exchange resin 101 within the water softening chamber 201. Furthermore, "surrounded" here means that the surface of the first electrode 103 is in contact with the surface of the weakly acidic cation exchange resin 101 throughout its entire circumference from top to bottom. However, the weakly acidic cation exchange resin 101 is typically spherical, and a clear flow path for the raw water must be ensured. Therefore, a configuration where the weakly acidic cation exchange resin 101 is not in seamless contact with the surface of the first electrode 103 but rather in partial contact throughout its entire circumference is also equivalent to "the first electrode 103 being surrounded by the weakly acidic cation exchange resin 101."

[0065] The upper end of the first electrode 103 is located below the water surface in the water softening chamber 201 at the beginning of the regeneration process. As a result, a first space 204 is formed in the upper part of the upper end of the first electrode 103 in the water softening chamber 201.

[0066] The water softening chamber 201 is filled with a weakly acidic cation exchange resin 101. That is, the first electrode 103 and the first space 204 are filled with a weakly acidic cation exchange resin 101.

[0067] Furthermore, in order to successfully regenerate the weakly acidic cation exchange resin 101, it is preferable that the water level at the beginning of the regeneration process is near the upper surface of the water softening chamber 201. In this embodiment, the water level at the beginning of the regeneration process is consistent with the upper surface of the water softening chamber 201.

[0068] The first electrode 103 is configured such that if the distance S from the water surface at the start of the regeneration process to the upper end of the first electrode 103 is compared with the distance T from the bottom surface of the water softening chamber 201 to the lower end of the first electrode 103, then the distance T is shorter than the distance S.

[0069] Therefore, during the regeneration process described later, the bubbles generated from the first electrode 103 cause the weakly acidic cation exchange resin 101 to flow, thereby improving the regeneration efficiency. Furthermore, in this embodiment, the lower end of the first electrode 103 is in contact with the bottom surface of the water softening chamber 201, T=0, therefore... Figure 2There is no record of T in it.

[0070] Noble metals or alloys of noble metals can be used as the material for the first electrode 103. This is because, by containing noble metals, the first electrode 103 functions as a catalyst for water electrolysis and will not dissolve even under acidic conditions. Examples of noble metal materials include platinum, iridium, or ruthenium.

[0071] Examples of electrodes include wire electrodes made of noble metal, electrodes with noble metal wires wound around the periphery of a support, and mesh-like noble metal electrodes. Alternatively, a metal rod other than noble metals such as titanium (Ti) can be used as a support and coated with a noble metal. However, if a dissimilar metal interface exists, degradation originating from that interface is likely to occur; therefore, noble metal or noble metal alloy monomers are preferred.

[0072] Neutralization chamber 202 is disposed within the outer casing 203 relative to the central axis I of the outer casing 203 on the outer periphery of the water softening chamber 201, and is a cylindrical space containing weakly basic anion exchange resin 102. The central axis of neutralization chamber 202 coincides with the central axis I of the outer casing 203. The inner side of the cylindrical shape of neutralization chamber 202 is in contact with the outer side of the inner peripheral diaphragm 105, and the outer side of the cylindrical shape is in contact with the inner side of the outer peripheral diaphragm 106. That is, neutralization chamber 202 surrounds the inner peripheral diaphragm 105 and is surrounded by the outer peripheral diaphragm 106. Neutralization chamber 202 is filled with weakly basic anion exchange resin 102. Furthermore, details regarding the inner peripheral diaphragm 105 and the outer peripheral diaphragm 106 will be described later.

[0073] The upper surface of the neutralization chamber 202 is in contact with the cover 112 in the same manner as the water softening chamber 201, and is configured to prevent water from flowing out. This is to prevent water from flowing out from the upper surface of the neutralization chamber 202 so that water bypasses the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 during the water softening process.

[0074] As the weakly basic anion exchange resin 102, resins having tertiary amines and quaternary amines as functional groups can be used. In this embodiment, a resin with a higher proportion of tertiary amines than quaternary amines is used.

[0075] The volume of the weakly basic anion exchange resin 102 filling the neutralization chamber 202 is larger than the volume of the weakly acidic cation exchange resin 101 filling the water softening chamber 201. This is because the neutralization chamber 202 is located on the outer periphery of the water softening chamber 201, and the volume of the neutralization chamber 202 is larger than the volume of the water softening chamber 201.

[0076] In the neutralization chamber 202, soft water with a neutral pH is generated by neutralizing the soft water produced in the water softening chamber 201. A second electrode 104 is provided in the neutralization chamber 202.

[0077] The second electrode 104 is an electrode that is not energized during the water softening process, but functions as a cathode during the regeneration of the weakly basic anion exchange resin 102. The second electrode 104 is surrounded by the weakly basic anion exchange resin 102 within the neutralization chamber 202.

[0078] Furthermore, here, "surrounded" means that the surface of the second electrode 104 is in contact with the surface of the weakly basic anion exchange resin 102 throughout its entire circumference from top to bottom. However, similar to the weakly acidic cation exchange resin 101, the weakly basic anion exchange resin 102 is generally spherical, and it is also necessary to ensure the flow path of the raw water (strictly speaking, acidic soft water). Therefore, the state in which the weakly basic anion exchange resin 102 is arranged throughout the entire circumference in a partial contact rather than in seamless contact with the surface of the second electrode 104 is also equivalent to "the second electrode 104 is surrounded by the weakly basic anion exchange resin 102".

[0079] The upper end of the second electrode 104 is located below the water surface in the neutralization chamber 202 at the beginning of the regeneration process (regeneration process of the weakly basic anion exchange resin 102) described later. As a result, a second space 205 is formed in the upper part of the upper end of the second electrode 104 in the neutralization chamber 202.

[0080] The neutralization chamber 202 is filled with a weakly basic anion exchange resin 102. That is, the second electrode 104 and the second space 205 are filled with a weakly basic anion exchange resin 102.

[0081] Furthermore, in order to successfully regenerate the weakly basic anion exchange resin 102, it is preferable that the water level at the start of the regeneration process is near the upper surface of the neutralization chamber 202. In this embodiment, the water level at the start of the regeneration process is consistent with the upper surface of the neutralization chamber 202.

[0082] The second electrode 104 is configured such that if the distance V from the water surface at the start of the regeneration process to the upper end of the second electrode 104 is compared with the distance W from the bottom surface of the neutralization chamber 202 to the lower end of the second electrode 104, then the distance W is shorter than the distance V.

[0083] Therefore, during the regeneration process described later, the bubbles generated from the second electrode 104 cause the weakly basic anion exchange resin 102 to flow, thereby improving the regeneration efficiency. Furthermore, in this embodiment, the lower end of the second electrode 104 is in contact with the bottom surface of the neutralization chamber 202, W=0, therefore... Figure 2 W is not recorded in the text.

[0084] Noble metals or alloys of noble metals can be used as the material for the second electrode 104. This is because, by containing a noble metal, the second electrode 104 functions as a catalyst for water electrolysis and will not dissolve even under acidic conditions. Examples of noble metal materials include platinum, iridium, or ruthenium.

[0085] The first electrode 103 and the second electrode 104 are arranged in pairs, and the pair of first electrodes 103 and second electrodes 104 are arranged on the same radius of the outer casing 203.

[0086] Therefore, compared to the case where a pair of electrodes are not on the same radius, the distance between the first electrode 103 and the second electrode 104 can be shortened, and the increase in power consumption due to the rise in voltage can be suppressed.

[0087] In this embodiment, two pairs of electrodes (first electrode 103a and second electrode 104a, first electrode 103b and second electrode 104b) are arranged on the same diameter of the cylindrical shape of the housing 203 (on the same straight line passing through the center when viewed from above).

[0088] Therefore, the two pairs of electrodes are equally arranged within the housing 203, thus suppressing the bias in the generation sites of hydrogen ions or hydroxide ions generated from the electrodes during regeneration. Consequently, the regeneration of the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 can be carried out efficiently.

[0089] The water softening chamber 201 and the neutralization chamber 202 are separated by an inner peripheral diaphragm 105. That is, the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 are separated by the inner peripheral diaphragm 105.

[0090] The inner peripheral diaphragm 105 is a water-permeable cylindrical membrane. The inner peripheral diaphragm 105 is in contact with the outer surface of the water softening chamber 201 such that its inner surface covers the outer surface of the water softening chamber 201. Furthermore, the outer surface of the inner peripheral diaphragm 105 is in contact with the inner surface of the neutralization chamber 202 such that it covers the inner surface of the neutralization chamber 202.

[0091] Thus, the inner circumferential diaphragm 105 allows the acidic soft water generated in the water softening chamber 201 to pass through, and separates the water softening chamber 201 from the neutralization chamber 202. Furthermore, the term "covering" only needs to be located around the object; it does not need to completely enclose the object.

[0092] To ensure water permeability and prevent the outflow of the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102, the inner peripheral membrane 105 has pores smaller than the particle size of the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102. Similarly, the lower limit of the particle size of the weakly acidic cation exchange resin 101 is approximately 0.3 mm, therefore the pore size of the inner peripheral membrane 105 is smaller than that.

[0093] Resin mesh can be used as the inner peripheral diaphragm 105. The material of the inner peripheral diaphragm 105 is preferably a material with heat resistance and chemical resistance, such as fluorinated resins, polyethylene resins, polypropylene resins, polyvinyl chloride resins, or polyvinylidene fluoride resins.

[0094] Alternatively, the inner peripheral diaphragm 105 can also be a structure provided with through holes or slits. During water softening, to ensure that water flows evenly from the water softening chamber 201 to the neutralization chamber 202, it is preferable to have through holes or slits evenly distributed on the surface of the inner peripheral diaphragm 105. The opening area of ​​each through hole or slit is preferably smaller than the particle size of the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102, and is such that it does not impede the flow of water during the water softening process.

[0095] The neutralization chamber 202 and the water supply section 108 (described later) are separated by the peripheral diaphragm 106.

[0096] The outer peripheral diaphragm 106 is a water-permeable cylindrical membrane. The outer peripheral diaphragm 106 is in contact with the outer surface of the neutralization chamber 202 such that its inner surface covers the outer surface of the neutralization chamber 202. In addition, the outer surface of the outer peripheral diaphragm 106 is in contact with the inner surface of the water supply section 108 such that it covers the inner surface of the water supply section 108.

[0097] This allows the soft water generated in the neutralization chamber to pass through, and separates the neutralization chamber 202 from the water delivery section 108. Furthermore, the term "covering" only needs to be around the object; it does not need to completely enclose the object.

[0098] To ensure water permeability and prevent the outflow of the weakly basic anion exchange resin 102, the outer peripheral diaphragm 106 has pores smaller than the particle size of the weakly basic anion exchange resin 102. The lower limit of the particle size of the weakly basic anion exchange resin 102 is approximately 0.3 mm, therefore the pore size of the outer peripheral diaphragm 106 is smaller than that.

[0099] Resin mesh can be used as the outer peripheral diaphragm 106. The material of the outer peripheral diaphragm 106 is preferably a material with heat resistance and chemical resistance, such as fluorinated resins, polyethylene resins, polypropylene resins, polyvinyl chloride resins, or polyvinylidene fluoride resins.

[0100] Alternatively, the outer peripheral diaphragm 106 can also be a structure with through holes or slits. During water softening, to ensure that water flows evenly from the neutralization chamber 202 to the water delivery section 108, it is preferable to have through holes or slits evenly distributed on the surface of the outer peripheral diaphragm 106. The opening area of ​​the through holes or slits is preferably smaller than the particle size of the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102, and is such that it does not impede the flow of water during the water softening process.

[0101] The upper surfaces of the water guiding section 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106 are covered by the cover section 112.

[0102] The cover 112 is a non-permeable structure, for example, a plate-shaped resin can be used. The cover 112 is in contact with and covers the upper surfaces of the water guiding section 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106, thereby separating the upper surfaces from the water delivery section 108 described later.

[0103] Therefore, water can be prevented from flowing out of each upper surface into the water delivery section 108. In other words, the cover 112 can form a water flow that allows raw water flowing in from the water guide inlet 111 to pass through the water guide section 107, the water softening chamber 201, the inner peripheral diaphragm 105, and the neutralization chamber 202, and then be delivered from the side surface of the outer peripheral diaphragm 106 to the side space 108a of the water delivery section 108.

[0104] The water supply unit 108 supplies soft water from the neutralization chamber 202 to the water supply outlet 110, which is located slightly above the upper part of the neutralization chamber 202. The central axis of the water supply unit 108 is aligned with the central axis I of the outer casing 203.

[0105] The water delivery unit 108 is disposed inside the housing 203 and has a side space 108a and an upper space 108b.

[0106] The side space 108a is located on the outer periphery of the neutralization chamber 202 relative to the central axis I of the outer shell 203, and is a cylindrical space surrounding the neutralization chamber 202. The side space 108a is in contact with the outer side of the outer peripheral diaphragm 106 on its inner cylindrical side and with the inner side of the outer shell 203 on its outer side. In other words, the side space 108a is the space located between the inner side of the outer shell 203 and the outer side of the outer peripheral diaphragm 106.

[0107] In a direction parallel to the central axis I, the total length of the side space 108a is longer than the total length of the neutralization chamber 202. When the bottom surfaces of the side space 108a and the neutralization chamber 202 are arranged on the same plane, the top surface of the side space 108a protrudes upward compared to the top surface of the neutralization chamber 202.

[0108] The upper space 108b is a cylindrical space located above the top surfaces of the water guiding section 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106. The upper space 108b's cylindrical top surface is in contact with the inner wall of the top surface of the outer casing 203, and its cylindrical bottom surface is in contact with the outer wall of the top surface of the cover 112. Furthermore, the outer cylindrical surface of the upper space 108b is in contact with the inner surface of the side space 108a.

[0109] The lateral space 108a and the upper space 108b are virtually separated by a boundary line 113, which is a virtual line. The boundary line 113 is a cylindrical virtual line whose central axis coincides with the central axis I, and is located in the upper part of the vertical direction of the outer peripheral diaphragm 106.

[0110] The water outlet 110 is located on the top surface of the housing 203 and is used to discharge water from the upper space 108b to the outside of the water softening device 100. The central axis of the water outlet 110 is aligned with the central axis I of the housing 203.

[0111] The exhaust valve 109 is located on the upper part of the water supply section 108 and is used to discharge gases such as oxygen and hydrogen generated in the water softening chamber 201 and neutralization chamber 202 during the regeneration process to the outside of the water softening device 100.

[0112] The above describes the structure of the water softening device 100.

[0113] Next, the two processes of the water softening device 100 (water softening process and regeneration process) will be explained.

[0114] First, the operation of the water softening device 100 and the principle of the water softening process will be explained.

[0115] In the water softening device 100, raw water flows from the outside into the lower part of the water guide section 107 through the water guide section inlet 111. The incoming raw water is transported from the lower part to the upper part of the water guide section 107 and flows out in the radial direction of the outer casing 203 through the holes provided in the side wall of the water guide section 107. That is, the raw water is sent out into the water softening chamber 201 through the holes of the water guide section 107.

[0116] The raw water sent to the water softening chamber 201 is softened by the weakly acidic cation exchange resin 101 that fills the interior of the water softening chamber 201. Specifically, the hardness components (calcium or magnesium ions) in the raw water exchange with the hydrogen ions adsorbed on the weakly acidic cation exchange resin 101, resulting in acidic soft water containing hydrogen ions.

[0117] The acidic soft water generated in the water softening chamber 201 is neutralized by flowing into the neutralization chamber 202 through the inner peripheral membrane 105, which serves as a permeable membrane. Specifically, hydrogen ions in the soft water are removed by adsorption onto the weakly basic anion exchange resin 102, thereby generating neutral soft water. Furthermore, during this neutralization reaction, anions such as sulfate ions contained in the soft water are also adsorbed onto the weakly basic anion exchange resin 102.

[0118] The neutral soft water generated in the neutralization chamber 202 flows into the water supply section 108 through the peripheral diaphragm 106, which serves as a permeable membrane.

[0119] The soft water flowing into the water delivery section 108 becomes an upward flow, rising within the side space 108a and flowing into the upper space 108b. The soft water flowing into the upper space 108b flows towards its center within the upper space 108b and is taken out from the water delivery outlet 110 located at the center of the upper surface of the water softening device 100.

[0120] In the water softening process, the raw water is softened in this way.

[0121] For efficient water softening, it is crucial to ensure sufficient contact between the ion exchange resin particles and the hard or acidic soft water. Therefore, water softening devices using ion exchange resins must be designed to ensure uniform water flow within the device. If the water does not flow uniformly, it will tend to follow the easiest path, resulting in insufficient contact with the ion exchange resin as it passes through the softening chamber 201 or neutralization chamber 202. Consequently, the water extracted from the water softening device 100 may not be soft water or may remain acidic.

[0122] On the other hand, in the water softening apparatus 100 of this embodiment, raw water is introduced into the apparatus from below the outer casing 203, and is taken out as softened water from the water supply outlet 110 provided at the top through the water supply section 108. This method of supplying water from the bottom to the top is called upward flow. In the case of upward flow, the ion exchange resin particles can flow easily, so the pressure loss when water passes through the water softening chamber 201 and the neutralization chamber 202 is small, and the water flows easily.

[0123] In addition, since the water softening device 100 is cylindrical, the distance from the central water guide section 107 to the outer water delivery section 108 is equal, and the water pressure applied to the water delivery section 108 is equal.

[0124] Furthermore, the water softening device 100 is configured such that water flows out from the water supply outlet 110 located at the center of the upper surface of the water softening device 100.

[0125] Due to the three characteristics of the water softening device 100—upward flow, cylindrical shape, and the position of the water outlet 110—the deviation in the flow path length of water passing through the water softening device 100 is reduced, allowing water to flow uniformly within the space of the water softening device 100. Therefore, the ion exchange resin can fully contact the raw water or acidic soft water, achieving highly efficient water softening.

[0126] Furthermore, the weakly acidic cation exchange resin 101 filling the water softening chamber 201 is an ion exchange resin containing carboxyl groups, and resins with a methacrylic acid backbone or an acrylic acid backbone can be used. Among these, resins with an acrylic acid backbone are preferred. In the case of a methacrylic acid backbone, the pKa (acid dissociation constant), a physical property of the resin, is typically around 5. On the other hand, the pKa of an acrylic acid backbone is around 3. During the water softening process, when H+ in the weakly acidic cation exchange resin... + When the pH of the water in the water softening chamber 201 is below pKa due to the release of cations such as hardness ions into the water through ion exchange, the COO2 responsible for ion exchange... - H + It no longer dissociates and cannot undergo ion exchange. Therefore, acrylic backbones with low pKa can exchange more cations compared to methacrylic backbones.

[0127] Furthermore, regarding the weakly basic anion exchange resin 102 filled in the neutralization chamber 202, it is preferable to use a resin with a higher proportion of tertiary amines than quaternary amines in terms of functional groups. The pKb of quaternary amines is approximately 11, which is higher than the pKb of tertiary amines, which is approximately 8. The pH value of the soft water after acidic soft water passes through the weakly basic anion exchange resin 102 is capped at the pKb of the amine groups. This is because, in the weakly basic anion exchange resin 102, if the pH value of the solution exceeds the pKb, the amine groups, as ion exchange groups, cannot function. The upper limit of the pH value of tap water is set at 8.5 according to the water quality standard. When the proportion of quaternary amines in the weakly basic anion exchange resin 102 is high, the pH value of the soft water tends to be alkaline compared to when the proportion of quaternary amines is low. In other words, if the proportion of quaternary amines is high, the pH value is higher than 8.5, which may no longer meet the water quality standard. Therefore, a higher proportion of tertiary amines is more preferable in order to bring the pH value of the soft water within the water quality standard.

[0128] Furthermore, in order to obtain soft water that meets water quality standards, the volume of the weakly basic anion exchange resin 102 used needs to be greater than the volume of the weakly acidic cation exchange resin 101. This is explained from the perspective of the ion exchange reaction rates of the two resins.

[0129] In order to obtain soft water that meets the water quality standards during the water softening process, the hardness of the raw water needs to be reduced to below 50 mg / L during the period when the raw water passes through the water softening chamber 201, and the pH value of the raw water needs to be restored from around 3 to neutral during the period when it passes through the neutralization chamber 202.

[0130] The amount of cations removed in water softening chamber 201 and the amount of anions and H+ removed in neutralization chamber 202 + The removal rate is determined by the rate of the ion exchange reaction and the time it takes for water to pass through the ion exchange resin. For example, from... Figure 3 As can be seen from the reactions during the water softening process shown in equations (1) and (2), the rate of the ion exchange reaction is determined by (a) the concentration of ion exchange groups and (b) the ion concentration in the hard water (Ca). 2+ or Cl - The time it takes for water to pass through the resin is determined by (c) the concentration of the resin and (d) the resin volume and (e) the water flow rate.

[0131] Of these five parameters, (b) the ion concentration in hard water and (e) the water flow rate cannot be controlled. (a) the concentration of ion exchange groups and (c) the rate constant of the ion exchange reaction are determined by the type and particle size of the resin. Therefore, the water quality standard required for the water softening process can be achieved by adjusting (d) the resin volume.

[0132] The volume ratio of each resin can be determined from the perspective of (a) the concentration of ion exchange groups and (c) the rate constant of the ion exchange reaction. The concentration of (a) ion exchange groups can be compared using the ion exchange equivalent (eq / L) of the ion exchange resin, i.e., the number of moles of ion exchange groups per unit volume of resin.

[0133] The ion exchange equivalent of the weakly acidic cation exchange resin 101 is approximately 4 eq / L, while the ion exchange equivalent of the weakly basic anion exchange resin 102 is the largest, at 2 eq / L. Therefore, the concentration of (a) ion exchange groups in the weakly acidic cation exchange resin 101 is higher. Furthermore, regarding the (c) reaction rate constant, the weakly basic anion exchange resin 102 has a higher rate constant due to its highly uniform particle size and small average particle size. Thus, the (c) reaction rate constant of the weakly basic anion exchange resin is higher, but regarding the (a) ion exchange group concentration, the concentration of (a) ion exchange groups in the weakly basic anion exchange resin 102 is approximately half that of the weakly acidic cation exchange resin 101.

[0134] Regarding the reaction rates obtained considering (a) and (c), the reaction rate of the weakly basic anion exchange resin 102 is slightly lower than that of the weakly acidic cation exchange resin 101. Therefore, regarding (d) the resin volume, the volume of the weakly basic anion exchange resin 102 needs to be greater than or equal to the volume of the weakly acidic cation exchange resin 101.

[0135] During this water softening process, if the adsorption capacity of hardness ions on the weakly acidic cation exchange resin 101 or the adsorption capacity of anions on the weakly basic anion exchange resin 102 increases, the resin performance of the water softening process will decrease. Therefore, a regeneration process is required.

[0136] Previously, when using BP membranes to regenerate water softening devices containing a mixture of weakly acidic cation exchange resins and weakly basic anion exchange resins, the following problem arose: desorbed hardness ions would re-adsorb onto the ion exchange resins, easily hindering the resin regeneration reaction. Therefore, to suppress the re-adsorption of desorbed hardness ions, water containing these ions needed to be discharged outside the device, requiring regeneration to be performed while water was being passed through. This water-passing operation resulted in increased wastewater discharge during the regeneration process. The reasons for this problem are explained below.

[0137] During the regeneration process of weakly acidic cation exchange resins and weakly basic anion exchange resins, the following occurred: Figure 3 The reactions shown in equations (3) and (4).

[0138] Since any regeneration reaction is reversible, not only Ca... 2+ or Cl - The forward desorption reaction also involves the reverse reactions of ion adsorption. The amino groups of the weakly basic anion exchange resin 102 react with OH groups... - Its affinity is far higher than Cl - And other anions. Therefore, Cl - The reverse reaction of adsorption is slow, and its impact is small. On the other hand, the carboxyl groups of the weakly acidic cation exchange resin 101 react with Ca... 2+ It has a relatively high affinity for Ca. Therefore, compared with weakly basic anion exchange resins, Ca... 2+ The reverse reaction of adsorption is rapid, and a certain amount of Ca is produced. 2+ Re-adsorption reaction.

[0139] As can be seen from equation (3), the rate of the forward reaction of the weakly acidic cation exchange resin is determined by H. + and Ca 2+ The concentration of H. + High concentration and Ca 2+Under low conditions, the regeneration reaction to the right is faster. However, in H... + Low concentration, Ca 2+ Under high conditions, the rate of regeneration reaction to the right decreases, and the rate of regeneration reaction to the left decreases. 2+ The rate of re-adsorption increases, making resin regeneration difficult to proceed.

[0140] In the regeneration process shown in Patent Document 1, H+ is simultaneously generated at the interface between the BP membrane and the ion exchange resin. + and OH - Generate H + and OH - The original purpose was to regenerate the resin, but the generated H + and OH - It is also consumed in side reactions other than the resin regeneration reaction. H₂ is present in these side reactions. + With OH - The recombining neutralization reaction, and the H+ exchange via a weakly basic anion exchange resin + Adsorption reaction. Due to the occurrence of multiple processes consuming these H+... + and OH - The reaction is such that the pH value of the resin tank in the regeneration process in Patent Document 1 is close to neutral.

[0141] When the pH value during the regeneration process is close to neutral, as explained in the mechanism of the regeneration reaction, in Ca... 2+ Under high temperatures, resin regeneration of weakly acidic cation exchange resins is difficult to achieve. Therefore, in the regeneration process of Patent Document 1, in order to make Ca... 2+ As the concentration decreases, it is necessary to desorb Ca from the weakly acidic cation exchange resin. 2+ Drainage operations that discharge water out of the system.

[0142] The drainage volume for this operation can be estimated as follows. In the case of a household water softener, the volume of ion exchange resin is generally around 20L. Depending on the void space in the resin-filled tank and the resin volume, the water volume in the tank is also approximately equal to the resin volume. If the water in the tank stagnates, the calcium and magnesium ion concentrations will immediately increase, so it is desirable to replace the total amount of water in the tank at least once every several tens of minutes.

[0143] For example, if the water in the tank is replaced every 10 minutes, a continuous flow of 2 L / min is required. The hydrogen and hydroxide ions that can be generated by the BP membrane are each in the range of several mmol / min. On the other hand, under standard operating conditions, the amount of calcium and magnesium ions desorbed from the resin is only a few mol (when softening 1000 L of raw water with a hardness of 250 mg / L per day, the hardness adsorbed on the resin is 2.5 mol), therefore regeneration requires several hours. Even assuming a regeneration time of 3 hours, the drainage volume is a massive amount: 2 L / min × 3 hr × 60 min / hr = 360 L.

[0144] Therefore, there is a need for a water softening device that can suppress or eliminate the need for drainage.

[0145] Below, refer to Figure 3 The operation of the water softening device 100 during the regeneration process and the principle of the regeneration process are explained.

[0146] During the regeneration process, firstly, raw water flows from the raw water supply source into the water guide section 107 via the water guide section inlet 111 and is filled into the water softening chamber 201 and the neutralization chamber 202. Next, each electrode is energized such that the potential of the first electrode 103, which is surrounded by the weakly acidic cation exchange resin 101, is higher than the potential of the second electrode 104, which is surrounded by the weakly basic anion exchange resin 102.

[0147] Therefore, a reaction that generates hydrogen ions occurs at the first electrode 103, which serves as the anode (see reference). Figure 3 Equation (5) shows that a reaction to generate hydroxide ions occurs at the second electrode 104, which serves as the cathode (refer to equation (5)). Figure 3 Equation (6)). In other words, hydrogen ions are generated in the water softening chamber 201 and hydroxide ions are generated in the neutralization chamber 202.

[0148] The weakly acidic cation exchange resin 101, which adsorbs hardness components during the water softening process, is exposed to hydrogen ions, thereby undergoing an exchange reaction between the hardness components and hydrogen ions. As a result, the weakly acidic cation exchange resin 101 is regenerated.

[0149] Furthermore, the weakly basic anion exchange resin 102, which has adsorbed anions through the water softening process, is exposed to hydroxide ions, thereby causing an exchange reaction between the adsorbed anions and hydroxide ions. As a result, the weakly basic anion exchange resin 102 is regenerated.

[0150] During the regeneration process, the weakly acidic cation exchange resin 101 and the weakly basic anion exchange resin 102 are regenerated in this manner.

[0151] In this embodiment, the first electrode 103 and the second electrode 104 are respectively arranged in two separate locations, the water softening chamber 201 and the neutralization chamber 202, surrounded by ion exchange resin. Therefore, hydrogen ions and hydroxide ions are generated respectively, and the generated ions are rapidly used for the regeneration of the ion exchange resin. If the generated hydrogen ions come into contact with hydroxide ions, a neutralization reaction occurs, and both ions are consumed. However, in the structure of this embodiment, a neutralization reaction caused by contact between hydrogen ions and hydroxide ions is less likely to occur, thus improving efficiency. Figure 3 The hydrogen ion concentration in formula (3) is sufficient to advance the regeneration reaction of the weakly acidic cation exchange resin 101 even in the presence of calcium ions. Therefore, the frequency of drainage aimed at reducing the calcium ion concentration in the water softening device 100 during the regeneration process can be reduced, or drainage can be eliminated, thereby reducing the amount of drainage.

[0152] Furthermore, the generated hydrogen ions and hydroxide ions are immediately consumed in the resin regeneration reaction, so the pH value near the first electrode 103 does not decrease significantly. Therefore, the electrode lifetime can be increased when platinum electrodes are used for both the first electrode 103 and the second electrode 104. This is because the dissolution of the oxide film naturally formed on the electrode surface due to hydrogen ions can be suppressed. If an oxide film is present, platinum dissolution reactions (e.g., platinum reacting with Cl-) can be prevented. - The reaction that generates platinum chloride ions through ionic reactions can increase electrode lifespan.

[0153] Furthermore, in this embodiment, the first electrode 103 is in contact with the bottom surface of the water softening chamber 201, and the second electrode 104 is in contact with the bottom surface of the neutralization chamber 202. That is, since the electrodes are positioned near the resin with a high concentration of adsorbed ions, the generated hydrogen ions and hydroxide ions are rapidly used in the resin regeneration reaction. Therefore, consumption due to the neutralization reaction of hydrogen ions and hydroxide ions is minimized, enabling efficient implementation of the regeneration process.

[0154] In detail, during the regeneration process, Figure 3 Formulas (3) and (4) as resin regeneration reactions and as H + and OH - Equations (5) and (6) of the generation reaction occur simultaneously. It is expected that H2O generated through the electrolysis of water will... + and OH - It is immediately consumed in the resin regeneration reaction, but this H + and OH - It will also be through H + and OH - The neutralization reaction between them is consumed. + and OH -The diffusion rate of H+ is faster than that of other ions, therefore, if it is not consumed in the resin regeneration reaction, it easily undergoes a neutralization reaction. When H+ is generated due to the neutralization reaction... + and OH - When the loss occurs, the required stoichiometric number of H moles, as determined by equations (3) and (4), must be generated. + and OH - This increases power consumption. Therefore, the rate of resin regeneration reaction needs to be greater than H₂. + and OH - The rate of the reaction.

[0155] The rate of resin regeneration reaction can be increased by improving (R-COO) - )2Ca 2+ and R3-NH + Cl - The concentration is achieved through [the process]. In the resin regeneration reaction with H […]. + and OH - During the regeneration process where the generation reaction occurs simultaneously, in order to make (R-COO - )2Ca 2+ and R3-NH + Cl - With increased concentration, it is effective to place the electrode near the resin that adsorbs more cations or anions during the water softening process.

[0156] In the water softening chamber 201, the closer to the bottom surface in the height direction, the higher the (R-COO) content. - )2Ca 2+ and (R-COO) - )2Mg 2+ The higher the concentration of R3-NH4+, the higher the concentration of R3-NH4+ in the neutralization chamber 202. Additionally, in the vertical direction, the closer to the bottom, the higher the concentration of R3-NH4+. + Cl - and (R3-NH + )2SO4 2- The higher the concentration, the more efficient the regeneration process can be achieved by connecting the first electrode 103 to the bottom surface of the water softening chamber 201 and the second electrode 104 to the bottom surface of the neutralization chamber 202.

[0157] (Example)

[0158] Below, refer to Figures 4-6 The following examples are used to illustrate the details of this disclosure.

[0159] use Figure 1The water softening device 100 shown underwent water softening and regeneration tests. In the water softening test, raw water was introduced through the water inlet pipe, and the hardness of the water extracted from the water softening device 100 was measured. Furthermore, hard water with a hardness of 310 mg / L was used as the raw water.

[0160] The regeneration test was conducted as follows: The platinum electrode on the weakly acidic cation exchange resin 101 side was connected to the positive terminal of a DC power supply, and the platinum electrode on the weakly basic anion exchange resin 102 side was connected to the negative terminal. A current of 5A was applied from the DC power supply for 6 hours. Regeneration was performed without replacing the water in the water softening unit 100 and without draining any water. During regeneration, a small amount of water was taken from the water softening chamber 201 and the neutralization chamber 202, and the pH value and ion concentration were measured.

[0161] After the first water softening test, a regeneration test was conducted, followed by another water softening test.

[0162] Figure 4 This graph shows the hardness change from 5 minutes to 40 minutes after water flow in the first and second water softening tests. It shows that by flowing water into the water softening device 100, the hardness decreased from 310 mg / L to below 50 mg / L. In the second water softening process performed after regeneration, the hardness also decreased to soft water levels. With raw water flowing into the water softening device 100 for 40 minutes, the high hardness of 310 mg / L was reduced to approximately 20 mg / L. This indicates that the water flow in the water softening device 100 is uniform; in other words, the resin particles in the water softening device 100 are used uniformly.

[0163] Figure 5 This is a graph showing the pH changes in the water softening chamber 201 and the neutralization chamber 202 during the regeneration process.

[0164] It can be seen that the pH changes from neutral (7-9) to weakly alkaline in neutral chamber 202, and from pH 2.3-3.3 to acidic in water softening chamber 201. Although the membrane used allows water to pass through easily, water softening chamber 201 is maintained as acidic, and neutralization chamber 202 is maintained as alkaline. In other words, it is clear that the weakly acidic cation exchange resin 101 can be independently exposed to H+. + Expose the weakly basic anion exchange resin 102 to OH- - .

[0165] Furthermore, although the pH value of the water softening chamber 201 is slightly acidic, it is weakly acidic at around pH 2.5, and although the pH value of the neutralization chamber 202 is slightly alkaline, it is weakly alkaline at around pH 9. If the resin consumes H... + and OH - The speed ratio generated by the electrode H + and OH- If the flow rate is slow, the pH value rises sharply in the neutralization chamber 202, becoming a strong base above pH 12, while the pH value decreases in the water softening chamber 201, becoming a strong acid below pH 2. This is because H₂, equivalent to 5A, is constantly generated from the electrodes. + or OH - Therefore, according to... Figure 5 The fact that the pH value did not drastically shift towards acidity or alkalinity, as shown, can be attributed to the H+ generated at the electrode. + and OH - It is immediately consumed through the resin regeneration reaction. It is known that by introducing large amounts of Ca... 2+ or Cl - Electrodes are placed near the resin, which allows the resin regeneration reaction to be controlled in a way that makes it a rate-controlling step.

[0166] Figure 6 This shows the Cl during the regeneration process. - Ions, Mg 2+ Ions and Ca 2+ A graph showing the change in the molar number of ions. Cl - Ions are released from the weakly basic anion exchange resin 102, Mg 2+ Ions and Ca 2+ Ions are released from the weakly acidic cation exchange resin 101. The molar number of any ion increases with increasing regeneration time. However, the molar number of ions remains almost unchanged between 5.5 and 6 hours.

[0167] like Figure 6 As shown, based on the increase in the molar number of ions associated with the increase in regeneration time, cations desorb from the weakly acidic cation exchange resin 101, and anions desorb from the weakly basic anion exchange resin 102, thus regeneration progresses. Furthermore, the fact that ion release occurs during regeneration even under conditions where no drainage is discharged during the regeneration process confirms that the amount of drainage during regeneration can be reduced in the structure of this embodiment. Additionally, based on the fact that the ion quantity remains almost unchanged in the final stage of regeneration, and... Figure 4 From the fact that the hardness of the regenerated soft water is approximately the same as that before regeneration, it can be seen that the resin can be regenerated to the level that the water softening device 100 of the embodiment can perform water softening.

[0168] The present disclosure has been described above based on the embodiments. These embodiments are illustrative, and those skilled in the art will understand that various modifications can exist in the combination of these constituent elements or processes, and such modifications are also within the scope of the present disclosure.

[0169] (Modified Example)

[0170] In Embodiment 1, the water softening device 100 is cylindrical, thus the two diaphragms (inner circumferential diaphragm 105 and outer circumferential diaphragm 106) are distinguished as inner circumferential and outer circumferential. However, depending on the shape of the water softening device 100, the two diaphragms are not necessarily located on the inner circumferential and outer circumferential sides respectively. The names "inner circumferential diaphragm" and "outer circumferential diaphragm" are merely used to distinguish the two types of diaphragms and do not indicate the positions of the inner circumferential diaphragm 105 and the outer circumferential diaphragm 106.

[0171] In the water softening device 100 according to Embodiment 1, the outer shell 203, the water guiding part 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106 are cylindrical, but not limited to this. For example, they can also be square.

[0172] In the water softening apparatus 100 according to Embodiment 1, a pipe with tiny holes on its surface is used as the water guide section 107, but it is not limited to this. For example, the central part of the water softening chamber 201 can be made into a gap, and this gap portion can be used as the water guide section 107. The same effect can be obtained in this way.

[0173] In the water softening apparatus 100 according to Embodiment 1, the water softening chamber 201 uses a container with its central portion cut into a cylindrical shape, but it is not limited to this. For example, the space divided by the outer periphery of the water guiding portion 107 and the inner periphery diaphragm 105 can also be used as the water softening chamber 201. The same effect can be obtained in this way.

[0174] In the water softening apparatus 100 according to Embodiment 1, the neutralization chamber 202 uses a container with its central portion cut into a cylindrical shape, but it is not limited to this. For example, the space divided by the inner peripheral diaphragm 105 and the outer peripheral diaphragm 106 can also be used as the neutralization chamber 202. The same effect can be obtained in this way.

[0175] In the water softening apparatus 100 according to Embodiment 1, the cover 112 is provided as a plate-shaped resin disposed across the upper surfaces of the water guiding section 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106, but is not limited thereto. The cover 112 can be constructed to prevent water from flowing out of the upper surfaces of the water guiding section 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106 to the water delivery section 108. For example, the cover 112 can also be constructed to independently cover the upper surfaces of the water guiding section 107, the water softening chamber 201, the inner peripheral diaphragm 105, the neutralization chamber 202, and the outer peripheral diaphragm 106 respectively. This can also prevent water from flowing out of the upper surfaces to the water delivery section 108.

[0176] In the water softening apparatus 100 according to Embodiment 1, the volume of the weakly basic anion exchange resin 102 is set to be greater than or equal to the volume of the weakly acidic cation exchange resin 101. However, it is preferable to change the volume ratio of the weakly basic anion exchange resin 102 to the weakly acidic cation exchange resin 101 according to the quality of the raw water and the target raw water treatment volume. When the hardness of the raw water is low or the raw water treatment volume is small, even if the volumes of the weakly basic anion exchange resin 102 and the weakly acidic cation exchange resin 101 are the same, the pH value of the softened water can be maintained near neutral. On the other hand, when the hardness of the raw water is high or the raw water treatment volume is large, the pH value may sometimes drop to below 6. Therefore, it is preferable to make the volume of the weakly basic anion exchange resin 102 greater than the volume of the weakly acidic cation exchange resin 101.

[0177] In the water softening apparatus 100 according to Embodiment 1, regarding the first electrode 103 and the second electrode 104, the electrode arrangement is not limited as long as the distance from the water surface at the start of the regeneration process to the upper end of the electrode is longer than the distance from the bottom surface of each chamber to the lower end of the electrode. Furthermore, as long as the generated H₂ can be suppressed... + and OH - The loss caused by the neutralization reaction to make H + and OH - The first electrode 103 and the second electrode 104 can be used without particularly limiting their configuration as they are consumed in the regeneration reaction of the ion exchange resin.

[0178] However, from the viewpoint of cost reduction, it is preferable that the first electrode 103 is positioned at any location in the height direction, from the bottom surface filled with the weakly acidic cation exchange resin 101 to halfway up the upper surface filled with the weakly acidic cation exchange resin 101. Furthermore, from the viewpoint of cost reduction, it is preferable that the second electrode 104 is positioned at any location in the height direction, from the bottom surface filled with the weakly basic anion exchange resin 102 to halfway up the upper surface filled with the weakly basic anion exchange resin 102.

[0179] In the water softening apparatus 100 described in Embodiment 1, the case of using the water softening apparatus 100 alone is described. However, it is also possible to connect multiple water softening apparatuses 100 in parallel to form a system consisting of two or more water softening apparatuses 100 connected in parallel. By connecting the water softening apparatuses 100 in parallel, the flow rate of each tank can be reduced. If the flow rate is reduced, the time for raw water to pass through the water softening apparatus 100 increases, and the amount of hardness removed during the water softening process increases.

[0180] Alternatively, multiple water softening devices 100 can be connected in series to form a system consisting of two or more water softening devices 100 connected in series. By connecting the water softening devices 100 in series, the theoretical number of plates in the ion exchange resin layer increases. This substantially increases the ion exchange capacity of the ion exchange resin that can be used. Specifically, assuming the total amount of ion exchange resin is the same, when comparing the ion exchange capacity of two ion exchange resins connected in series with the ion exchange capacity of a single ion exchange resin, the ion exchange capacity of a device consisting of two ion exchange resins connected in series is approximately five times that of a single-tank device.

[0181] Furthermore, the water softening devices 100 can be connected in series and in parallel to form a system consisting of four or more water softening devices 100. When configured using this connection method, the hardness removal rate during the water softening process is the highest compared to the cases described above where only parallel connections are used or only series connections are used.

[0182] (Implementation Method 2)

[0183] In the technology described in Patent Document 1, hardness ions desorbed from the ion exchange resin are re-adsorbed onto the ion exchange resin, which can easily hinder the reaction during resin regeneration. Therefore, in order to remove the desorbed hardness ions, regeneration needs to be performed while water is flowing through it. Due to this water flow operation, there is a problem that the amount of wastewater discharged during resin regeneration increases.

[0184] This disclosure was made in view of the problems existing in the prior art. This disclosure provides a water softening apparatus capable of suppressing drainage during regeneration and enabling efficient regeneration of the resin.

[0185] The water softening apparatus disclosed herein comprises: a water softening chamber having a weakly acidic cation exchange resin for generating soft water from raw water containing hardness components; a neutralization chamber having a weakly basic anion exchange resin for neutralizing the soft water; a diaphragm separating the water softening chamber and the neutralization chamber in a manner allowing soft water to pass through; a first electrode that functions as an anode during the regeneration of the weakly acidic cation exchange resin; a second electrode that functions as a cathode during the regeneration of the weakly basic anion exchange resin; and a control unit that controls the regeneration of the weakly acidic cation exchange resin and the weakly basic anion exchange resin. The first electrode is disposed in the water softening chamber surrounded by the weakly acidic cation exchange resin, and the second electrode is disposed in the neutralization chamber surrounded by the weakly basic anion exchange resin. The control unit executes the following processes: a water softening process, in which the water to be treated flows in from the bottom of the water softening chamber and sequentially through the water softening chamber and the neutralization chamber, thereby obtaining soft water; a regeneration process, in which electricity is applied to the first electrode and the second electrode, hydrogen ions are generated from the first electrode and hydroxide ions are generated from the second electrode through water electrolysis, and the generated hydrogen ions are used to regenerate the weakly acidic cation exchange resin and the generated hydroxide ions are used to regenerate the weakly basic anion exchange resin; a cleaning process, in which cations released from the weakly acidic cation exchange resin during the regeneration process are discharged from the water softening chamber and anions released from the weakly basic anion exchange resin are discharged from the neutralization chamber; and an electrode cleaning process, in which the first electrode is connected to the negative electrode and the second electrode is connected to the positive electrode during or after the regeneration process, so that the solids adhering to the surface of the second electrode during the regeneration process are dissolved.

[0186] According to this disclosure, a water softening apparatus is provided that can suppress drainage during regeneration and enable efficient regeneration of resin.

[0187] The embodiments of this disclosure will now be described with reference to the accompanying drawings. Furthermore, the following embodiments are merely examples embodying this disclosure and are not intended to limit the technical scope of this disclosure. Additionally, the figures described in each embodiment are schematic diagrams, and the ratios of the size and thickness of the constituent elements in each figure may not necessarily reflect actual dimensional ratios.

[0188] Reference Figure 7 , Figure 8 and Figure 9 The water softening apparatus 1100 according to Embodiment 2 of this disclosure will be described.

[0189] Figure 7 This is a schematic diagram showing the structure of the water softening device 1100 according to Embodiment 2 of this disclosure. Figure 8 This is a perspective view showing the structure of the water softening apparatus 1100 according to Embodiment 2 of this disclosure. Figure 9This is a cross-sectional view showing the structure of the water softening apparatus 1100 according to Embodiment 2 of this disclosure. Furthermore, in Figures 7-9 The various elements of the water softening device 1100 are conceptually shown in the diagram. Additionally, in... Figure 8 In this description, the weak acidic cation exchange resin 1213 and the weak basic anion exchange resin 1214 are omitted.

[0190] The water softening device 1100 is a device that generates neutral soft water from raw water containing hardness components supplied from the outside. Furthermore, raw water refers to water (the water to be treated) introduced into the water softening device 1100 from the raw water supply pipe 1104 (described later), such as well water or tap water. The raw water contains hardness components (calcium ions or magnesium ions).

[0191] By using the water softening device 1100 to perform the water softening process, it is possible to obtain neutral soft water with reduced hardness from raw water with high hardness, so that soft water can be used even in areas where the raw water has high hardness.

[0192] Furthermore, after a certain period of water softening, the water softening device 1100 performs a regeneration process, as described later, to regenerate the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214. Details regarding the water softening and regeneration processes will be described later.

[0193] like Figure 7 As shown, the water softening device 1100 includes a raw water supply pipe 1104, a housing 1109, a soft water supply pipe 1105, a drain pipe 1107, and a control unit 1110.

[0194] The raw water supply pipe 1104 is a pipe that connects the water source such as tap water to the inlet 1207 of the water guide section, and has a raw water conductivity measuring section 1101 in its flow path.

[0195] The raw water conductivity measuring unit 1101 calculates the total ion concentration of the raw water flowing into the raw water supply pipe 1104. The calculated total ion concentration information of the raw water is sent to the control unit 1110, which will be described later.

[0196] The outer shell 1109 is a hollow cylindrical component, and the softening of raw water and the regeneration of ion exchange resin are carried out inside the outer shell 1109.

[0197] like Figure 8 and Figure 9 As shown, within the hollow space of the outer casing 1109, a water guiding section 1203, a water softening chamber 1209, a neutralization chamber 1210, and a water delivery section 1204 are sequentially arranged from the side near the central axis I connecting the upper and lower surfaces of the outer casing 1109 towards the outer periphery.

[0198] A water guide inlet 1207 is provided at the center of the lower surface of the outer casing 1109, i.e., on the central axis I. A water delivery outlet 1206 is provided at the center of the upper surface of the outer casing 1109, i.e., on the central axis I. The central axis I of the outer casing 1109 is aligned with the central axes of the water guide 1203, the water softening chamber 1209, the neutralization chamber 1210, and the water delivery section 1204.

[0199] The water guide inlet 1207 is located on the bottom surface of the housing 1109 and is used to supply raw water to the water guide section 1203. The central axis of the water guide inlet 1207 is aligned with the central axis I of the housing 1109.

[0200] The water guide section 1203 is a cylindrical component that connects to the water guide section inlet 1207 at its lower end. The water guide section 1203 guides raw water into the water softening device 1100 to supply it to the water softening chamber 1209. As the water guide section 1203, pipes or other pipes with internal space can be used.

[0201] The water guiding section 1203 is configured to ensure that the raw water introduced into the water softening device 1100 flows evenly to the water softening chamber 1209 and the neutralization chamber 1210. Specifically, the water guiding section 1203 is located in the center of the housing 1109, and the outer periphery of the water guiding section 1203 is in contact with the water softening chamber 1209. In other words, the water guiding section 1203 is located on the central axis I.

[0202] Furthermore, the water guiding section 1203 extends from the lower part of the water softening chamber 1209 and the neutralization chamber 1210 to the upper part, or more precisely, from the lower end to the upper end. The length of the portion of the water guiding section 1203 that supplies raw water to the water softening chamber 1209 and the neutralization chamber 1210 is equal to the height of the water softening chamber 1209 and the neutralization chamber 1210.

[0203] The water guiding section 1203 has multiple holes on its side surface through which raw water is fed from the central axis I of the outer casing 1109 toward the outer periphery, i.e., toward the water softening chamber 1209. Preferably, the multiple holes are evenly arranged circumferentially on the side surface of the water guiding section 1203. With this structure, the raw water introduced into the device can flow evenly to the water softening chamber 1209 and the neutralization chamber 1210. Therefore, raw water is supplied without leakage to the particles of the weakly acidic cation exchange resin 1213 filled in the water softening chamber 1209 and the particles of the weakly basic anion exchange resin 1214 filled in the neutralization chamber 1210. Thus, the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214 can be utilized efficiently overall.

[0204] The water guiding section 1203 has multiple pores on its side surface that are smaller than the particle size of the weakly acidic cation exchange resin 1213. The lower limit of the particle size of the weakly acidic cation exchange resin 1213 is about 0.3 mm, therefore the diameter of the pores provided on the surface of the water guiding section 1203 is smaller than that. As a result, water permeability is not hindered, and the ion exchange resin is prevented from flowing out of the water softening chamber 1209.

[0205] The water softening chamber 1209 is located within the outer casing 1109, positioned relative to the central axis I of the outer casing 1109 on the outer periphery of the water guiding section 1203. It is a cylindrical space (first space 1211) containing a weakly acidic cation exchange resin 1213. The central axis of the water softening chamber 1209 coincides with the central axis I of the outer casing 1109. The water softening chamber 1209 is connected to the water guiding section 1203 on its inner cylindrical side, to a water-permeable cylindrical membrane (inner peripheral diaphragm 1215) on its outer side, and to a cover 1208 on its upper surface. A plurality of first electrodes 1201 (e.g., first electrode 1201a and first electrode 1201b) are provided in the water softening chamber 1209.

[0206] The first electrode 1201 is an electrode that is not energized during water softening but functions as an anode during the regeneration of the weakly acidic cation exchange resin 1213. The first electrode 1201 is surrounded by the weakly acidic cation exchange resin 1213 within the water softening chamber 1209. Furthermore, "surrounded" here means that the surface of the first electrode 1201 is in contact with the surface of the weakly acidic cation exchange resin 1213 throughout its entire circumference from top to bottom. However, the weakly acidic cation exchange resin 1213 is typically spherical, and a clear flow path for the raw water must be ensured. Therefore, a configuration where the weakly acidic cation exchange resin 1213 is partially in contact with the surface of the first electrode 1201 rather than in a seamless manner is also equivalent to "the first electrode 1201 being surrounded by the weakly acidic cation exchange resin 1213".

[0207] The neutralization chamber 1210 is located within the outer casing 1109, positioned relative to the central axis I of the outer casing 1109 on the outer periphery of the water softening chamber 1209. It is a cylindrical space (second space 1212) containing a weakly basic anion exchange resin 1214. The central axis of the neutralization chamber 1210 coincides with the central axis I of the outer casing 1109. The neutralization chamber 1210 is in contact with the outer surface of the inner peripheral diaphragm 1215 on its cylindrical inner side, and with the inner surface of the water-permeable cylindrical membrane, the outer peripheral diaphragm 1216, on its cylindrical outer side. Its upper surface is in contact with the cover 1208. A plurality of second electrodes 1202 (e.g., second electrode 1202a and second electrode 1202b) are provided in the neutralization chamber 1210.

[0208] The second electrode 1202 is an electrode that is not energized during the water softening process, but functions as a cathode during the regeneration of the weakly basic anion exchange resin 1214. The second electrode 1202 is surrounded by the weakly basic anion exchange resin 1214 within the neutralization chamber 1210.

[0209] Furthermore, here, "surrounded" means that the surface of the second electrode 1202 is in contact with the surface of the weakly basic anion exchange resin 1214 throughout its entire circumference from top to bottom. However, similar to the weakly acidic cation exchange resin 1213, the weakly basic anion exchange resin 1214 is generally spherical, and it is also necessary to ensure the flow path of the raw water (strictly speaking, acidic soft water). Therefore, the state in which the weakly basic anion exchange resin 1214 is arranged throughout the entire circumference in a partial contact rather than in seamless contact with the surface of the second electrode 1202 is also equivalent to "the second electrode 1202 being surrounded by the weakly basic anion exchange resin 1214".

[0210] The water softening device 1100 includes a circuit (including a power supply circuit) for electrode cleaning that connects the first electrode 1201 to the negative electrode and the second electrode 1202 to the positive electrode.

[0211] The water supply unit 1204 supplies soft water from the neutralization chamber 1210 to the water supply outlet 1206, which is located slightly above the upper part of the neutralization chamber 1210. The central axis of the water supply unit 1204 is aligned with the central axis I of the outer casing 1109.

[0212] An exhaust valve 1205 for discharging air from the housing 1109 is provided in the water supply section 1204.

[0213] The water supply outlet 1206 is located on the top surface of the housing 1109 and is used to discharge water from the water supply section 1204 to the outside of the water softening device 1100. The central axis of the water supply outlet 1206 is aligned with the central axis I of the housing 1109.

[0214] Return to Figure 7 The soft water supply pipe 1105 connects the water supply outlet 1206 to the destination of the soft water supply. Its flow path includes a soft water conductivity measuring unit 1102 and a water volume measuring unit 1103. Furthermore, a drain pipe 1107 branches off from the soft water supply pipe 1105 midway through its flow path. A soft water supply pipe on / off valve 1106 is installed downstream of the branch point between the soft water supply pipe 1105 and the drain pipe 1107.

[0215] The soft water conductivity measuring unit 1102 calculates the total ion concentration of the soft water delivered from the water supply outlet 1206. The calculated total ion concentration information of the soft water is sent to the control unit 1110, which will be described later.

[0216] As for the raw water conductivity measuring unit 1101 and the soft water conductivity measuring unit 1102, any device capable of measuring the resistance of water can be used without any problems.

[0217] Drainage pipe 1107 is a branch pipe that extends from soft water supply pipe 1105 upstream of soft water supply pipe on / off valve 1106, and is used for drainage during the regeneration process. Drainage pipe 1107 has a drain pipe on / off valve 1108 in its flow path.

[0218] The water volume measuring unit 1103 is a component that measures the amount of water supplied to the water softening device 1100, and can be equipped with devices such as a water meter that can measure the cumulative water volume. The measured water volume information is sent to the control unit 1110, which will be described later.

[0219] The control unit 1110 controls the execution of each process described below: the water softening process, the regeneration process, the drainage process, the cleaning process, and the electrode cleaning process.

[0220] The control unit 1110 can be implemented as hardware through components and mechanical devices, such as the CPU (Central Processing Unit) of a computer, and as software through computer programs. Therefore, these functional blocks can be implemented in various forms through a combination of hardware and software.

[0221] The control unit 1110 includes an adsorption amount estimation unit 1111, a storage unit 1112, and a timing unit 1113.

[0222] The adsorption capacity estimation unit 1111 uses the total ion concentration of raw water calculated by the raw water conductivity measuring unit 1101, the total ion concentration of soft water calculated by the soft water conductivity measuring unit 1102, and the total flow rate measured by the water volume measuring unit 1103 to calculate the total amount of ions adsorbed on the water softening device 1100.

[0223] The storage unit 1112 stores the information sent to the control unit 1110 and the information calculated in the control unit 1110.

[0224] The timing unit 1113 measures the elapsed time from the start of the regeneration process, and more specifically, measures the elapsed time from the start of energizing the first electrode 1201 and the second electrode 1202.

[0225] The above describes the structure of the water softening device 1100.

[0226] Next, the processes performed by the water softening device 1100 (water softening process, regeneration process, cleaning process, and electrode cleaning process) will be explained.

[0227] First, the operation of the water softening device 1100 and the principle of the water softening process will be explained.

[0228] In the water softening device 1100, raw water flows from the outside into the lower part of the water guide section 1203 through the water guide section inlet 1207. The incoming raw water is conveyed from the lower part to the upper part of the water guide section 1203 and flows out radially into the outer casing 1109 through holes provided in the side wall of the water guide section 1203. That is, the raw water is sent out into the water softening chamber 1209 through the holes of the water guide section 1203.

[0229] The raw water sent to the water softening chamber 1209 is softened by the weakly acidic cation exchange resin 1213 that fills the interior of the water softening chamber 1209. Specifically, the hardness components (calcium or magnesium ions) in the raw water exchange with the hydrogen ions adsorbed on the weakly acidic cation exchange resin 1213, resulting in acidic soft water containing hydrogen ions.

[0230] The acidic soft water generated in the water softening chamber 1209 is neutralized by flowing into the neutralization chamber 1210 through the inner peripheral membrane 1215, which serves as a permeable membrane. Specifically, hydrogen ions in the soft water are removed by adsorption onto the weakly basic anion exchange resin 1214, thereby generating neutral soft water. Furthermore, during this neutralization reaction, anions such as sulfate ions contained in the soft water are also adsorbed onto the weakly basic anion exchange resin 1214.

[0231] The neutral soft water generated in the neutralization chamber 1210 flows into the water supply section 1204 through the peripheral diaphragm 1216, which serves as a permeable membrane.

[0232] The soft water flowing into the water delivery section 1204 becomes an upward flow, rising within the side space 1204a of the water delivery section 1204 and flowing into the upper space 1204b of the water delivery section 1204. The soft water flowing into the upper space 1204b flows towards its center within the upper space 1204b and is taken out from the water delivery outlet 1206 located at the center of the upper surface of the water softening device 1100.

[0233] In the water softening process, the raw water is softened in this way.

[0234] During water softening, if the adsorption capacity of hardness ions on the weakly acidic cation exchange resin 1213 or the adsorption capacity of anions on the weakly basic anion exchange resin 1214 increases, the resin performance of the water softening process will decrease. Therefore, a regeneration process is required.

[0235] In the regeneration process, firstly, raw water flows from the raw water supply source into the water guide section 1203 via the water guide inlet 1207 and is transported to the water softening chamber 1209 and the neutralization chamber 1210. Next, each electrode is energized such that the potential of the first electrode 1201, which is surrounded by a weakly acidic cation exchange resin 1213, is higher than the potential of the second electrode 1202, which is surrounded by a weakly basic anion exchange resin 1214.

[0236] Therefore, a reaction that generates hydrogen ions occurs at the first electrode 1201, which serves as the anode (see reference). Figure 10 Equation (15) shows that a reaction to generate hydroxide ions occurs at the second electrode 1202, which serves as the cathode (see formula (15)). Figure 10 Formula (16)). In other words, hydrogen ions are generated in the water softening chamber 1209 and hydroxide ions are generated in the neutralization chamber 1210.

[0237] The weakly acidic cation exchange resin 1213, which adsorbs hardness components during the water softening process, is exposed to hydrogen ions, thereby undergoing an exchange reaction between the hardness components and hydrogen ions. This process regenerates the weakly acidic cation exchange resin 1213.

[0238] Furthermore, the weakly basic anion exchange resin 1214, which has adsorbed anions through the water softening process, is exposed to hydroxide ions, thereby undergoing an exchange reaction between the adsorbed anions and hydroxide ions. As a result, the weakly basic anion exchange resin 1214 is regenerated.

[0239] During the regeneration process, the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214 are regenerated in this manner.

[0240] During the regeneration process, the water softening device 1100 sets the regeneration time based on the conductivity of the raw water or softened water before and after water is introduced into the housing 1109, or the amount of water introduced into the housing 1109.

[0241] Specifically, at the start of the water softening process, the raw water conductivity measuring unit 1101 is activated to measure the conductivity of the raw water flowing through the raw water supply pipe 1104. Meanwhile, the softened water conductivity measuring unit 1102 is activated to measure the conductivity of the softened water flowing through the softened water supply pipe 1105. Furthermore, the water volume measuring unit 1103 measures the water volume flowing through the casing 1109. The measured raw water conductivity, softened water conductivity, and water volume are sent to the control unit 1110 and stored in the storage unit 1112.

[0242] The ions to be removed in water softening chamber 1209 are mainly Mg. 2+ and Ca 2+ The hardness ions to be removed in the neutralization chamber 1210 are mainly HCO3- ions. - Cl- and SO4 2- The anions are adsorbed. Based on the principle of electroneutrality, the molar number of cations adsorbed in the water softening chamber 1209 is equal to the molar number of anions adsorbed in the neutralization chamber 1210. Therefore, the difference between the conductivity measured by the raw water conductivity measuring unit 1101 and the conductivity measured by the softened water conductivity measuring unit 1102 originates from the total amount of Mg and Ca salts removed in the water softening device 1100. Thus, since the conductivity difference is the value of the removed ion concentration, it is possible to cope with changes in the water quality of the raw water and the softened water, and to calculate the adsorption amount with high accuracy.

[0243] The adsorption capacity estimation unit 1111 estimates the amount of ions adsorbed in the water softening device 1100. Specifically, it calculates the difference between the conductivity of the raw water stored in the storage unit 1112 and the conductivity of the softened water. This difference represents the concentration of ions adsorbed in the water softening device 1100. The adsorption capacity estimation unit 1111 multiplies the ion concentration obtained as the difference by the total flow rate measured by the water volume measuring unit 1103. Thus, the amount of ions adsorbed in the water softening device 1100 during the regeneration process is estimated.

[0244] Here, the current value and energizing time required to regenerate the water softening device 1100 by removing the estimated adsorbed ions will be explained.

[0245] During the regeneration process, 1 mole of H is generated from 1 mole of electrons. + One mole of electrons generates one mole of OH-. - Additionally, in order for 1 mole of hardness ions to be released from the resin, 2 moles of H+ are required. + Therefore, the molar number of ions adsorbed in the water softening chamber 1209 and the H2O required for resin regeneration... + The relationship between current value and time is used Figure 10 Equation (12) represents this.

[0246] The control unit 1110 determines the current value and energizing time required for the regeneration of the weak acid cation exchange resin 1213 and the weak base anion exchange resin 1214 based on the number of moles of adsorbed ions estimated by the adsorption amount estimation unit 1111 and formula (12).

[0247] In the water softening device 1100, it is preferable to vary the applied current value as the regeneration process progresses. The reason for this will be explained.

[0248] As the regeneration process progresses, the ions adsorbed during water softening are released from the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214 into the water, thus gradually increasing the ion concentration in the water. In other words, if the time elapsed from the start of the regeneration process is longer, the conductivity of the water in the water softening device 1100 increases compared to when energization begins, resulting in a decrease in voltage. On the other hand, at the start of energization, the voltage is high because the ion concentration in the water softening device 1100 is low. Therefore, if the current value is kept constant from the start of energization, the voltage is high at the start of energization and gradually decreases as the energization time progresses.

[0249] In the final stage of the regeneration process Figure 10 In equations (13) and (14), (R-COO) - )2Ca 2+ and R3-NH + Cl - The concentration decreases, thus slowing down the regeneration rate. As a result, such as... Figure 11 As shown, the consumption ratio of the added hydrogen ions decreases, and the conversion rate decreases. When the consumption ratio is low, even if hydrogen ions or hydroxide ions at a concentration higher than that that the resin can consume are added to the weakly acidic cation exchange resin 1213 or the weakly basic anion exchange resin 1214, they do not react with the ions in the resin. Instead, the hydrogen ions and hydroxide ions react with each other, thus resulting in a loss.

[0250] In other words, based on the voltage characteristics at the initial stage of the regeneration process described above, when applying current, it is preferable not to immediately increase the current to the current value determined by the adsorption amount estimation unit 1111, but to gradually increase the current. This allows the voltage to be kept low, thus reducing power consumption.

[0251] Furthermore, in the final stage of the regeneration process, it is preferable to gradually reduce the current based on the resin's reactivity characteristics. This suppresses the reaction of excess ions with each other, reduces current waste, and minimizes power consumption.

[0252] To perform such a time-varying change in the applied current, a timing unit 1113 is used.

[0253] The storage unit 1112 stores a first reference value, which represents the timing of current changes, and a second reference value, which represents the time when the current reaches its maximum value and the time from which it begins to decrease. The first reference value is set to approximately 30 minutes to 1 hour from the start of power-on. The second reference value is set to a time later than the first reference value and 30 minutes to 1 hour earlier than the end of power-on.

[0254] As in equation (12), the current and time required for the regeneration process are determined by the hardness of the adsorbed material. Therefore, if the time from the start of energization to the first reference value and the time from the end of energization to the second reference value are extended, the maximum current value or regeneration time needs to be increased.

[0255] The timing unit 1113 measures the elapsed time from the start of applying current to the first electrode 1201 and the second electrode 1202. When the elapsed time measured by the timing unit 1113 reaches a first reference value, the control unit 1110 stops the applied current value from increasing and maintains the current value. Then, when the elapsed time measured by the timing unit 1113 reaches a second reference value, the control unit 1110 decreases the applied current value. Furthermore, the increase in current value from the start of energization to the first reference value, or the decrease in current value from the second reference value to the end of energization, can be linear or stepwise.

[0256] During the regeneration process, during the determined energizing time, a determined current value is applied to the first electrode 1201 and the second electrode 1202 to regenerate the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214.

[0257] After the regeneration process, ions released from the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214 are present at high concentrations in the water softening chamber 1209 and the neutralization chamber 1210. Therefore, a cleaning operation is required within the water softening device 1100. If the cleaning is insufficient, residual ions will mix into the water during the water softening process, potentially leading to incomplete water softening. Therefore, a cleaning process is performed after the regeneration process.

[0258] During the cleaning process, in the water softening device 1100, the soft water supply pipe on / off valve 1106 is closed, and the drain pipe on / off valve 1108 is opened. As a result, the water in the water softening chamber 1209 and the neutralization chamber 1210 is discharged outside the water softening device 1100 via the drain pipe 1107. Furthermore, by allowing raw water to flow in from the raw water supply pipe 1104, the device is prepared to restart the regeneration process.

[0259] When the end of the cleaning process is determined by time, the cleaning time, from the start to the end of the cleaning process, is set to be longer than the residence time, which is the time from when the raw water flows into the water softening chamber 1209 to when the raw water flows out of the neutralization chamber 1210. As a result, water containing a large number of desorbed hardness ions present in the water softening chamber 1209 can be discharged, and the water in the water softening chamber 1209 can be replaced with raw water.

[0260] During the regeneration process, solid calcium carbonate adheres to the electrode surface of the second electrode 1202. If the amount of calcium carbonate deposited on the electrode surface increases, problems such as higher voltage when energized and difficulty in removing calcium carbonate from the electrode surface arise. Therefore, it is necessary to periodically perform an electrode cleaning process to remove calcium carbonate from the cathode surface.

[0261] During the electrode cleaning process, the first electrode 1201 is connected to the negative electrode, and the second electrode 1202 is connected to the positive electrode. That is, electrode cleaning is performed by reversing the polarity of the electrodes relative to the regeneration process. Through this operation, H2O is generated from the second electrode 1202. + Calcium carbonate on the surface of the second electrode 1202 reacts with H + Dissolves through reaction. Electrode cleaning is performed during or after the regeneration process.

[0262] As described above, in the water softening device 1100, the softening of raw water by the water softening process and the maintenance of the water softening device 1100 by the regeneration process, the cleaning process and the electrode cleaning process are repeatedly performed.

[0263] (Implementation Method 3)

[0264] The water softening apparatus 1100b according to Embodiment 3 of this disclosure differs from that of Embodiment 2 in that, during the regeneration process, an electrolyte other than hydrogen ions and hydroxide ions is introduced into the water softening chamber and the neutralization chamber. Otherwise, the structure is the same as that of the water softening apparatus 1100 according to Embodiment 2. Hereinafter, the descriptions already given in Embodiment 2 will be omitted as appropriate, and the differences from Embodiment 2 will be mainly explained.

[0265] During the regeneration process, especially at the start of power-on, if the electrolyte concentration of the water in the water softening device 1100b is low, the voltage when the first electrode 1201 and the second electrode 1202 are energized will be high, resulting in problems such as the inability to apply the specified current or increased power consumption.

[0266] Therefore, in this embodiment, an electrolyte is supplied to reduce the resistance of water during electrolysis in the regeneration process. Specifically, the electrolyte in the raw water is utilized by supplying raw water. The water softening device 1100b is mainly used in hard water areas. The raw water in hard water areas contains a large number of ions, represented by hardness ions, at high concentrations. Therefore, by supplying raw water, the ions in the raw water before softening can be used as the electrolyte at the beginning of the regeneration process.

[0267] The electrolyte supply method in the regeneration process that utilizes raw water is explained.

[0268] Before energizing the first electrode 1201 and the second electrode 1202 during the regeneration process, the water softening device 1100b is filled with raw water. Specifically, after closing the soft water supply pipe on / off valve 1106, the drain pipe on / off valve 1108 is opened, thereby supplying raw water to the water softening device 1100b using tap water pressure. In other words, the water softening device 1100b is equipped with a raw water supply pipe 1104 that serves as an electrolyte supply unit.

[0269] After a certain period of time has elapsed since the start of the water supply, the drain valve 1108 is closed to end the drainage. Then, energizing the first electrode 1201 and the second electrode 1202 begins. Furthermore, if the elapsed time from the introduction of raw water into the water softening device 1100b until the start of energizing is prolonged, ions in the raw water will be adsorbed by the weakly acidic cation exchange resin 1213 or the weakly basic anion exchange resin 1214. Therefore, it is preferable to start energizing as soon as possible after closing the drain valve 1108. The drain valve 1108 should be open for at least the time required to change the water in the water softening device 1100b. If tap water is used for domestic purposes, the drain valve 1108 may be open for several minutes.

[0270] (Implementation Method 4)

[0271] The difference between the water softening apparatus 1100c according to Embodiment 4 and Embodiment 3 is that, during the regeneration process, it includes a reagent slow-release unit 1302 as an electrolyte injection unit. This reagent slow-release unit 1302 introduces electrolytes other than hydrogen ions and hydroxide ions as reagents into the raw water flowing into the water softening chamber 1209 and the neutralization chamber 1210. Other than this, the structure is the same as that of the water softening apparatus 1100b according to Embodiment 3. Hereinafter, the descriptions already given in Embodiment 3 will be omitted as appropriate, and the differences from Embodiment 3 will be mainly explained.

[0272] Reference Figure 12 The water softening apparatus 1100c according to this embodiment will be described.

[0273] Figure 12 This is a conceptual diagram showing the structure of the water softening device 1100c according to this embodiment. Furthermore, in Figure 12 The various elements of the water softening device 1100c are conceptually shown in the diagram.

[0274] The raw water supply pipe 1104a is a pipe that connects the raw water supply source, such as the tap water pipe, to the inlet 1207 of the water guide section. At the branch point set in the middle of the flow path (raw water supply pipe 1104a), a chemical addition pipe 1301 branches out, and at the confluence point downstream of the branch point, the chemical addition pipe 1301 is connected again.

[0275] The soft water supply pipe 1105 is equipped with a soft water supply pipe on / off valve 1106 at a position downstream of the branch point with the drainage pipe 1107.

[0276] The raw water supply pipe 1104a has a raw water supply pipe on / off valve 1304 on the downstream side of the branch point with the chemical addition pipe 1301 and on the upstream side of the confluence point.

[0277] The chemical dosing pipe 1301 is a pipe that bypasses the branch point of the raw water supply pipe 1104a to the confluence point. It has a chemical dosing pipe on / off valve 1303 and a chemical slow-release section 1302 in the flow path.

[0278] A slow-release unit 1302 is located downstream of the chemical dosing pipe on / off valve 1303 and is used to add chemicals to the raw water flowing into the chemical dosing pipe 1301. This supplies electrolytes to the raw water. Any reagent that is harmless to humans can be used as the added reagent; specifically, food-grade reagents are preferred. Examples include sodium sulfate, sodium chloride, calcium chloride, or sodium polyphosphate. Polarity is not particularly limited, but since it is used for drinking water, a neutral salt with a neutral pH is preferred; among neutral salts, sulfates or phosphates, which have less impact on anode life, are more preferable.

[0279] The raw water supply pipe on / off valve 1304 is installed on the raw water supply pipe 1104a. It is a valve whose opening degree can be adjusted. By opening and closing the valve or adjusting the opening degree, the electrolyte concentration in the raw water can be adjusted.

[0280] When it is desired to increase the electrolyte concentration in the raw water, the raw water supply pipe valve 1304 is closed when the chemical addition pipe valve 1303 is opened. As a result, all the raw water flowing into the casing 1109 passes through the chemical release section 1302, thus becoming water with a higher concentration of electrolytes compared to the original raw water.

[0281] On the other hand, when it is desired to reduce the electrolyte concentration in the raw water, the raw water supply pipe valve 1304 is also opened when the chemical addition pipe valve 1303 is opened. As a result, only a portion of the raw water flowing into the casing 1109 passes through the chemical release section 1302, while the rest does not. Therefore, water with a higher electrolyte concentration than the raw water and a lower electrolyte concentration than when the raw water supply pipe valve 1304 is closed is obtained.

[0282] The flow path structure during the water softening process and the flow path structure during the regeneration process in Implementation Method 4 will be described.

[0283] During the water softening process, the raw water supply pipe valve 1304 and the soft water supply pipe valve 1106 are opened, while the reagent addition pipe valve 1303 and the drain pipe valve 1108 are closed, so that raw water is introduced into the water softening device 1100c. Thus, the raw water is softened in the same way as in Embodiment 2.

[0284] During the regeneration process, before supplying raw water, the soft water supply pipe valve 1106 is closed, and the drain pipe valve 1108 and the chemical addition pipe valve 1303 are opened. Furthermore, to prevent chemicals from entering the soft water supply pipe 1105, it is preferable to close the soft water supply pipe valve 1106 before opening the drain pipe valve 1108 and the chemical addition pipe valve 1303. By supplying raw water in this state, since the chemical addition pipe valve 1303 is open, chemicals are released from the chemical release unit 1302 into the raw water. The chemicals dissolve in the raw water, resulting in electrolyte-containing water with a high concentration of electrolytes.

[0285] With the water softening device 1100c filled with electrolyte-containing water, electrolysis is performed using the first electrode 1201 and the second electrode 1202 to regenerate the ion exchange resin. After a certain period of time from the start of electrolysis, the drain valve 1108 and the reagent addition valve 1303 are closed. Furthermore, to reduce the pressure of tap water applied to the water softening device 1100c, it is best to close the reagent addition valve 1303 before closing the drain valve 1108. Additionally, the time the electrolyte-containing water circulates in the water softening device 1100c, i.e., the time the drain valve 1108 is open, should preferably be longer than the time required to change the water in the water softening device 1100c. When tap water is used for domestic water supply, the time the electrolyte-containing water circulates in the water softening device 1100c can be several minutes.

[0286] (Implementation Method 5)

[0287] The difference between the water softening apparatus 1100d according to Embodiment 5 of this disclosure and Embodiment 3 is that the electrolyte used at the start of energization during the regeneration process is the drainage discharged after the previous regeneration process. Other than this, the structure is the same as that of the water softening apparatus 1100b according to Embodiment 3. Hereinafter, the descriptions already given in Embodiment 3 will be omitted as appropriate, and the differences from Embodiment 3 will be mainly explained.

[0288] Reference Figure 13 The water softening apparatus 1100d according to this embodiment will be described.

[0289] Figure 13 This is a conceptual diagram showing the structure of the water softening device 1100d according to this embodiment. Furthermore, in Figure 13The various elements of the water softening device 1100d are conceptually shown in the diagram.

[0290] The raw water supply pipe 1104b is a pipe that connects the raw water supply source, such as a tap water pipe, to the inlet 1207 of the water guide section. It is connected to the reclaimed water return pipe 1405, which will be described later, at the confluence point in the middle of the flow path.

[0291] The soft water supply pipe 1105a is a pipe that connects the outlet 1206 of the water supply section to the destination of the soft water supply, and a drain pipe 1107a branches off midway through the flow path. The soft water supply pipe 1105a is equipped with a soft water supply pipe on / off valve 1106 at a position downstream of the branch point with the drain pipe 1107a.

[0292] Drainage pipe 1107a branches off from soft water supply pipe 1105a upstream of soft water supply pipe on / off valve 1106, and is used for drainage during the regeneration process. Drainage pipe 1107a has a drain pipe on / off valve 1108 in its flow path. Drainage pipe 1107a is connected to soft water supply pipe 1105a at one end and to storage chamber 1401 at the other end.

[0293] Storage chamber 1401 is a tank for storing cleaning water discharged from water softening chamber 1209 and neutralization chamber 1210 during the cleaning process described later, and includes inlet 1402, first water outlet 1403 and second water outlet 1404.

[0294] The inlet 1402 is an opening for introducing water into the storage chamber 1401 and is connected to the drain pipe 1107a. The inlet 1402 is preferably located in the upper part of the shell of the storage chamber 1401.

[0295] The first water inlet 1403 is an opening for discharging water from the storage chamber 1401 to the water softening device 1100d, and is connected to the drainage pipe 1107a for water supply and drainage. The first water inlet 1403 is preferably located on the upper part of the housing of the storage chamber 1401.

[0296] The second water inlet 1404 is connected to the reclaimed water return pipe 1405 described later, and is an opening used to send water from the storage chamber 1401 to the reclaimed water return pipe 1405.

[0297] The reclaimed water return pipe 1405 is a pipe connected at one end to the second water inlet 1404 and at the other end to the raw water supply pipe 1104b. It is used to supply the drainage in the storage chamber 1401 to the raw water supply pipe 1104b. The reclaimed water return pipe 1405 is equipped with a reclaimed water return pipe on / off valve 1406 in the middle of the flow path.

[0298] In other words, the water softening device 1100d has a storage chamber 1401 that serves as an electrolyte supply unit.

[0299] The flow path structure during the water softening process and the flow path structure during the regeneration process in Implementation Method 5 will be described.

[0300] During the water softening process, the raw water is introduced into the water softening device 1100d by setting the soft water supply pipe on / off valve 1106 open and the drain pipe on / off valve 1108 and the reclaimed water return pipe on / off valve 1406 closed. Thus, the raw water is softened in the same way as in Embodiment 2.

[0301] During the regeneration process, before supplying raw water, the softened water supply pipe on / off valve 1106 is closed, and the drain pipe on / off valve 1108 and the regenerated water return pipe on / off valve 1406 are opened. Through this opening and closing operation, a portion of the raw water introduced from the raw water supply pipe 1104 flows out of the water softening device 1100d from the first water inlet 1403 of the storage chamber 1401, while the remaining raw water is supplied back to the outer casing 1109 through the second water inlet 1404 via the regenerated water return pipe 1405 from the storage chamber 1401. With this structure, water from the storage chamber 1401 can be supplied to the outer casing 1109 using tap water pressure, thus eliminating the need for a pump.

[0302] Since the wastewater discharged after the regeneration process contains a large number of ions released during the process, the electrolyte concentration in the raw water can be increased by effectively utilizing this wastewater and supplying it to the raw water. The ions discharged from the resin during the regeneration process are the same ions originally present in the raw water, so it can be used without any problems from a safety perspective.

[0303] The timing for storing the electrolyte-containing wastewater in storage chamber 1401 is during the cleaning process performed after the regeneration process.

[0304] The cleaning process is as follows: cations released from the weakly acidic cation exchange resin 1213 through the regeneration process are discharged from the water softening chamber 1209, and anions released from the weakly basic anion exchange resin 1214 are discharged from the neutralization chamber 1210.

[0305] In the initial stage of the cleaning process, water containing a high concentration of ions released from the resin is discharged from the outer casing 1109. However, as the cleaning progresses, the ion concentration in the wastewater decreases, becoming close to that of the original water. Therefore, from the viewpoint of increasing the electrolyte concentration when energizing the first electrode 1201 and the second electrode 1202, it is preferable to retain the water from the initial stage of the cleaning process in the storage chamber 1401 as much as possible. By arranging the inlet 1402 and the first water outlet 1403 above the casing of the storage chamber 1401, a structure is created that facilitates water retention within the storage chamber 1401, making it easier to retain the water from the initial stage of the cleaning process in the lower part of the storage chamber 1401.

[0306] (Implementation Method 6)

[0307] The water softening apparatus 1100e according to Embodiment 6 of this disclosure differs from Embodiment 2 in that it includes multiple water softening modules. Otherwise, its structure is the same as that of the water softening apparatus 1100 according to Embodiment 2. Hereinafter, the descriptions already given in Embodiment 2 will be omitted as appropriate, and the differences from Embodiment 2 will be mainly explained.

[0308] Reference Figure 14 The water softening apparatus 1100e according to this embodiment will be described.

[0309] Figure 14 This is a conceptual diagram showing the structure of the water softening device 1100e according to this embodiment. Furthermore, in Figure 14 The various elements of the water softening device 1100e are conceptually shown in the diagram.

[0310] The water softening device 1100e has multiple water softening modules. In this embodiment, it has two water softening modules 1501 (water softening module 1501a and water softening module 1501b).

[0311] The water softening module 1501 includes the housing 1109 and the structure inside the housing 1109 as described in Embodiment 2. Specifically, it includes at least a water softening chamber, a neutralization chamber, and a diaphragm.

[0312] The water softening module 1501a, located upstream, and the water softening module 1501b, located downstream, are connected by a connecting pipe 1502. Specifically, the inlet 1207 of the water softening module 1501a is connected to the raw water supply pipe 1104, and the outlet 1206 of the water delivery section is connected to the connecting pipe 1502. Similarly, the inlet 1207 of the water softening module 1501b is connected to the connecting pipe 1502, and the outlet 1206 of the water delivery section is connected to the softened water supply pipe 1105.

[0313] A conductivity meter 1503a is installed in the raw water supply pipe 1104, a conductivity meter 1503b is installed in the connecting pipe 1502, and a conductivity meter 1503c is installed in the soft water supply pipe 1105.

[0314] The conductivity meter 1503a measures the conductivity of the water flowing in the raw water supply pipe 1104, that is, the water flowing into the water softening module 1501a.

[0315] The conductivity meter 1503b measures the conductivity of the water flowing in the connecting pipe 1502, that is, the water flowing out of the water softening module 1501a.

[0316] The conductivity meter 1503c measures the conductivity of the water flowing in the soft water supply pipe 1105, that is, the water flowing out of the water softening module 1501b.

[0317] When water softening modules are connected in multiple stages, the ion adsorption capacity of each module is often inconsistent. For example, when two water softening modules are connected, raw water flows into the upstream water softening module, and water whose hardness has been reduced due to the water softening treatment in the upstream module flows into the downstream water softening module.

[0318] according to Figure 10 As shown in equation (11), if the water hardness decreases, the reaction rate of hardness adsorption decreases, thus reducing the amount of hardness adsorbed in the water softening chamber 1209. The amount adsorbed in the neutralization chamber 1210 also decreases. Therefore, if the ion adsorption amounts of each water softening module are compared, the adsorption amount in the upstream water softening module is greater than that in the downstream water softening module. Therefore, it is desirable to set the current value or energizing time according to the resin consumption of each water softening module, which also leads to a reduction in power consumption. Therefore, in the water softening device 1100e, during the regeneration process, the optimal current value and current application time are calculated for each water softening module.

[0319] During the regeneration process, conductivity meters 1503a, 1503b, and 1503c are used to measure the conductivity of the water flowing in each flow path, and the difference in conductivity before and after each water softening module is calculated. Additionally, the cumulative water flow to the water softening module is measured by the water flow measurement unit 1103. Based on the obtained conductivity difference and cumulative water flow, the current value and energizing time required for regeneration of the water softening chamber and neutralization chamber of each water softening module are calculated.

[0320] (Implementation Method 7)

[0321] The difference between the water softening device 1100f according to Embodiment 7 of this disclosure and Embodiment 2 is that, during the regeneration process, in order to reduce the ion concentration of the water in the water softening device 1100f, a drainage process for draining water from the device is performed. Other than this, the structure is the same as that of the water softening device 1100 according to Embodiment 2. Hereinafter, the descriptions of contents already described in Embodiment 2 will be omitted as appropriate, and the differences from Embodiment 2 will be mainly explained.

[0322] Reference Figure 15 The water softening apparatus 1100f according to this embodiment will be described. Figure 15 This is a conceptual diagram showing the structure of the water softening device 1100f according to this embodiment. Furthermore, in Figure 15 The various elements of the water softening device 1100f are conceptually shown in the diagram.

[0323] The water softening device 1100f has an upstream drain pipe 1601.

[0324] The upstream drain pipe 1601 is a branch pipe from the raw water supply pipe 1104, which discharges water from the water softening device 1100f during the drainage process. The upstream drain pipe 1601 is equipped with a discharge valve 1602.

[0325] The drain valve 1602 is a valve installed on the upstream drain pipe 1601. By opening the drain valve 1602, the water in the water softening device 1100f is discharged from the upstream drain pipe 1601 to the outside of the water softening device 1100f.

[0326] The drainage pipe 1107 is equipped with a drainage flow measurement unit 1603. The drainage flow measurement unit 1603 measures the flow rate of water flowing into the drainage pipe 1107.

[0327] During the regeneration process, the water softening unit 1100f performs a drainage process to remove water from the water softening unit 1100f, thereby reducing the ion concentration of the water within the water softening unit 1100f. The rationale for this process is explained.

[0328] During the regeneration process, if the energizing time of the first electrode 1201 and the second electrode 1202 is increased, the Ca in the regenerated water will increase. 2+ and Mg 2+ Concentration of cations such as ions, Cl - and SO4 2- As the concentration of anions increases. If the concentration of these ions increases, then Figure 10 Ca of equations (13) and (14) 2+ and Cl - As the concentration increases, the rate of the reaction that reverses the regeneration of the ion exchange resins increases. Consequently, the ions desorbed from each ion exchange resin hinder the regeneration reaction of the weakly acidic cation exchange resin 1213 and the weakly basic anion exchange resin 1214. In the structure of this disclosure, the regeneration reaction proceeds even without drainage, but drainage to reduce the concentration further improves the efficiency of the regeneration reaction.

[0329] The timing of drainage during the drainage process is determined by the timing unit 1113. Specifically, when the elapsed time from the start of the regeneration process, as measured by the timing unit 1113, exceeds a certain time, the control unit 1110 opens the discharge valve 1602, discharging the water with high ion concentration present in the water softening device 1100f to the outside through the upstream drain pipe 1601. As a result, the ion concentration of the water in the water softening device 1100f decreases, and the regeneration efficiency during the regeneration process increases.

[0330] When determining the timing of drainage based on the elapsed time from the start of the regeneration process, it is best to increase the frequency of drainage from the beginning of regeneration to the middle stage, and decrease the frequency in the latter half of the regeneration process.

[0331] like Figure 11 As shown, the reaction efficiency is high until the middle stage of the regeneration process, resulting in a large change in the desorbed ion concentration over time. On the other hand, the reaction efficiency is low in the latter half of the regeneration process, resulting in a smaller change in the desorbed ion concentration over time. Therefore, the frequency of drainage in the latter half of the regeneration process can be less than that in the middle stage. In other words, it is preferable to extend the time interval between drainage processes as the regeneration process progresses. Considering both suppressing the amount of drainage and reducing reaction hindrance caused by desorbed ions, the drainage interval is preferably about 30 minutes. For example, a drainage process is performed every 20 minutes until the middle stage of the regeneration process, and every 40 minutes in the latter half of the regeneration process.

[0332] If drainage is complete, the control unit 1110 closes the discharge valve 1602, and then opens the drain pipe on / off valve 1108. As a result, raw water flows in from outside the water softening unit 1100f, filling it and enabling the regeneration process to be performed again. The timing for ending the flow of raw water is determined by the drainage volume measuring unit 1603. Specifically, the flow ends at the point when the flow rate, as measured by the drainage volume measuring unit 1603, becomes greater than the combined volume of the water softening chamber 1209 and the neutralization chamber 1210.

[0333] The present disclosure has been described above based on the embodiments. These embodiments are illustrative, and those skilled in the art will understand that various modifications can exist in the combination of these constituent elements or processes, and such modifications are also within the scope of the present disclosure.

[0334] (Modified Example)

[0335] In Embodiment 2, the water volume measuring unit 1103 is provided on the soft water supply pipe 1105, but it is not limited to this. For example, even if the water volume measuring unit 1103 is provided in the middle of the piping of the raw water supply pipe 1104, the flow rate of water introduced into the water softening device 1100 can be measured.

[0336] In Embodiment 2, the following method is used when determining the amount of ions adsorbed in the water softening device 1100 by the adsorption amount estimation unit: the concentration of ions adsorbed in the water softening device 1100 is calculated based on the difference in conductivity measured by the raw water conductivity measuring unit 1101 and the softened water conductivity measuring unit 1102, and the reduced ion concentration is multiplied by the total water flow measured by the water flow measuring unit 1103, but is not limited to this method.

[0337] For example, the following method can also be used: calculate the ion concentration of the raw water based on the conductivity measured by the raw water conductivity measuring unit 1101, and multiply the calculated raw water ion concentration by the total flow rate measured by the water volume measuring unit 1103. If this calculation method is used, the amount of adsorbed ions corresponding to changes in the raw water quality can be determined without installing a soft water conductivity measuring unit 1102.

[0338] Alternatively, the following method can be used: multiply the total flow rate measured by the water volume measuring unit 1103 by the pre-measured ion concentration. If this calculation method is used, the amount of adsorbed ions adsorbed in the water softening device 1100 can be determined without setting up the raw water conductivity measuring unit 1101 and the soft water conductivity measuring unit 1102.

[0339] In Embodiment 2, the applied current value is controlled based on the elapsed time from the start of energization measured by the timing unit 1113, but is not limited to this. For example, a voltage measuring unit that measures the voltage and voltage-time change when energizing the first electrode 1201 and the second electrode 1202 can also be used to control the applied current value. When changing the current value using the voltage measuring unit, the voltage-time change is measured and the current is gradually changed. At the start of energization, a current lower than the target current value determined by the adsorption amount estimation unit 1111 is applied, and the current is increased at the point where the voltage-time change decreases. Then, the step of further increasing the current at the point where the voltage-time change decreases is repeated. It is preferable to increase the current in about 10 steps. This is because, although the amount of current increase also depends on the amount of current increase, the voltage remains constant for about 5 minutes from the time the current increases.

[0340] In Embodiment 2, the timing of ending the cleaning process is determined based on time, but it is not limited to this. For example, the timing of ending the cleaning process can also be determined by the drainage volume measuring unit 1603 installed in the drainage pipe 1107. The drainage process can be ended when the water volume measured by the drainage volume measuring unit 1603 from the start of the drainage process is greater than or equal to the volume of the water softening chamber 1209 and the neutralization chamber 1210.

[0341] Alternatively, the timing for ending the cleaning process can be determined by a drainage conductivity measuring unit installed in the drainage pipe 1107. The drainage conductivity measuring unit measures the conductivity of the drainage flowing from the water softening device 1100 during the cleaning process. Since the cleaning process is performed using raw water, if desorbed ions in the water softening device 1100 can be discharged outside the device, the hardness of the discharged water will be lower than that of the raw water. The drainage conductivity measuring unit measures the drainage conductivity and compares it with the conductivity measured by the raw water conductivity measuring unit 1101. The cleaning process ends when the drainage conductivity becomes lower than that of the raw water.

[0342] In Embodiment 7, the timing for drainage is determined based on the elapsed time from the start of the regeneration process, as measured by the timing unit 1113, but is not limited to this. For example, a regenerated water conductivity measuring unit that measures the conductivity of the water in the water softening device 1100f and the change in conductivity over time can also be used to determine the timing for drainage. In this case, when the conductivity of the regenerated water conductivity measuring unit exceeds a certain value, the control unit 1110 controls the opening and closing of the drain pipe on / off valve 1108 or the discharge valve 1602 to drain water from the water softening device 1100f.

[0343] When the timing of drainage is determined by the conductivity measuring unit, the drainage pipe on / off valve on the drainage pipe 1107 is opened when the conductivity exceeds a certain value and then closed after a specified time. The water-conducting section, where hardness ions tend to be retained, can be used as a location for measuring conductivity. This is because hardness ions desorbed from the weakly acidic cation exchange resin 1213 during regeneration tend to diffuse into and remain in the water-conducting section. Compared to the weakly basic anion exchange resin 1214, the regeneration of the weakly acidic cation exchange resin 1213 is more easily hindered by desorbed ions.

[0344] There is no specific limit to the conductivity value used as a benchmark for drainage, but it is expected to be around 3 mS / cm. During regeneration, when the conductivity of the water in the drainage section reaches 3 mS / cm, the hardness increases to approximately 1000 mg / L. Even at hardness levels higher than 1000 mg / L, the regeneration of the weakly acidic cation exchange resin 1213 proceeds, but efficiency decreases due to the influence of the reverse reaction. Therefore, if drainage is implemented when the conductivity reaches approximately 3 mS / cm, the effect of preventing the reverse reaction can be further achieved.

[0345] The water softening device disclosed herein can reduce the frequency of drainage or eliminate the need for drainage itself, thereby reducing the amount of drainage. As a side effect, it can also shorten the regeneration time and increase the electrode life, thus making it useful as a water softening device, etc.

[0346] (Implementation Method 8)

[0347] The technology described in Patent Document 1 has the following problem: the hardness ions desorbed from the ion exchange resin will be re-adsorbed into the ion exchange resin, which can easily hinder the reaction during resin regeneration.

[0348] This disclosure was made in view of the problems existing in the prior art. This disclosure provides a water softening apparatus capable of efficiently regenerating resin.

[0349] The water softening apparatus disclosed herein comprises: a water softening chamber having a weakly acidic cation exchange resin for generating soft water from raw water containing hardness components; a neutralization chamber located on the outer periphery of the water softening chamber having a weakly basic anion exchange resin for neutralizing the soft water; a diaphragm separating the water softening chamber and the neutralization chamber in a manner that allows soft water to pass through; a water guiding section located on the inner periphery of the water softening chamber for supplying raw water to the water softening chamber; a water delivery section for conveying the neutralized soft water generated in the neutralization chamber to the outside; and a control section for controlling the regeneration of the weakly acidic cation exchange resin. The control unit performs the following processes: a water softening process, in which raw water flows in from the water guide section and sequentially passes through a water softening chamber and a neutralization chamber to obtain neutralized soft water; a regeneration process, in which, after performing a water softening process for a predetermined period, water electrolysis is performed, and the generated hydrogen ions are used to regenerate a weakly acidic cation exchange resin; and a drainage process, in which cations released from the weakly acidic cation exchange resin during the regeneration process are discharged from the water softening chamber, and anions released from the weakly basic anion exchange resin are discharged from the neutralization chamber. During the drainage process, water containing cations is discharged from the water guide section. According to this disclosure, a water softening apparatus capable of efficiently regenerating resin can be provided.

[0350] The embodiments of this disclosure will now be described with reference to the accompanying drawings. Furthermore, the following embodiments are merely examples embodying this disclosure and are not intended to limit the technical scope of this disclosure. Additionally, the figures described in each embodiment are schematic diagrams, and the ratios of the size and thickness of the constituent elements in each figure may not necessarily reflect actual dimensional ratios.

[0351] Reference Figure 16 , Figure 17 and Figure 18 The water softening apparatus 2100 according to Embodiment 8 of this disclosure will be described.

[0352] Figure 16 This is a schematic diagram showing the structure of the water softening apparatus 2100 according to Embodiment 8 of this disclosure. Figure 17 This is a perspective view showing the structure of the water softening apparatus 2100 according to Embodiment 8 of this disclosure. Figure 18 This is a cross-sectional view showing the structure of the water softening apparatus 2100 according to Embodiment 8 of this disclosure. Furthermore, in Figures 16-18 The various elements of the water softening device 2100 are conceptually shown in the diagram. Additionally, in... Figure 17 In this document, the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214 are omitted.

[0353] The water softening device 2100 is a device that generates neutral soft water from raw water containing hardness components supplied from the outside. Furthermore, the raw water refers to the water (the water to be treated) introduced into the water softening device 2100 from the raw water supply pipe 2104 (described later), such as well water or tap water. The raw water contains hardness components (calcium ions or magnesium ions).

[0354] By using the water softening device 2100 to perform the water softening process, it is possible to obtain neutral soft water with reduced hardness from raw water with high hardness, and even in areas where the raw water has high hardness, soft water can be used.

[0355] Furthermore, after a certain period of water softening, the water softening device 2100 performs a regeneration process, as described later, to regenerate the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214. Details regarding the water softening and regeneration processes will be described later.

[0356] like Figure 16 As shown, the water softening device 2100 includes a raw water supply pipe 2104, a drainage pipe 2107, a soft water supply pipe 2105, a bypass pipe 2114, a housing 2109, and a control unit 2110.

[0357] The raw water supply pipe 2104 is a pipe that connects a raw water source, such as tap water, to the inlet 2207 of the water guide section (described later). A raw water conductivity measuring unit 2101 is provided along its flow path. The raw water supply pipe 2104 is connected to the drainage pipe 2107 downstream of the raw water conductivity measuring unit 2101 and upstream of the connection point with the water guide inlet 2207. A drainage pipe on / off valve 2108 is provided at the connection point between the raw water supply pipe 2104 and the drainage pipe 2107.

[0358] The raw water conductivity measuring unit 2101 calculates the total ion concentration of the raw water flowing into the raw water supply pipe 2104. The calculated total ion concentration information of the raw water is sent to the control unit 2110, which will be described later.

[0359] Drainage pipe 2107 is a branch pipe that extends from the raw water supply pipe 2104 at the drain pipe on / off valve 2108, and is used for drainage during the drainage process described later.

[0360] The drain pipe on / off valve 2108 is a valve installed at the connection between the raw water supply pipe 2104 and the drain pipe 2107. By opening and closing the drain pipe on / off valve 2108, it is possible to switch between supplying raw water from the water source through the raw water supply pipe 2104 to the water inlet 2207, or discharging the water inside the housing 2109 (described later) to the outside of the water softening device 2100 through the raw water supply pipe 2104 and the drain pipe 2107.

[0361] The soft water supply pipe 2105 is a pipe that connects the water delivery outlet 2206 (described later) to the destination of the soft water supply. Its flow path includes a soft water conductivity measuring unit 2102, a water volume measuring unit 2103, and a soft water supply pipe on / off valve 2106.

[0362] The soft water conductivity measuring unit 2102 calculates the conductivity from the water supply outlet 2206 (reference). Figure 17 The total ion concentration of the delivered soft water is calculated and sent to the control unit 2110, which will be described later.

[0363] As for the raw water conductivity measuring unit 2101 and the soft water conductivity measuring unit 2102, they can be used without any problems as long as they are devices capable of measuring the resistance of water.

[0364] The water volume measuring unit 2103 is a component that measures the amount of water supplied to the water softening device 2100, and can be equipped with devices such as a water meter that can measure the cumulative water volume. The measured water volume information is sent to the control unit 2110, which will be described later.

[0365] The soft water supply pipe on / off valve 2106 is a valve installed on the soft water supply pipe 2105. By opening and closing the soft water supply pipe on / off valve 2106, it is possible to switch whether to supply soft water to the outside.

[0366] The bypass pipe 2114 is a branch pipe that originates from the raw water supply pipe 2104 upstream of the connection between the raw water supply pipe 2104 and the drainage pipe 2107, and connects to the soft water supply pipe 2105 upstream of the soft water supply pipe on / off valve 2106. Through the bypass pipe 2114, raw water is supplied from the raw water supply source to the water delivery outlet 2206 during the drainage and cleaning processes described later. The bypass pipe 2114 is equipped with a bypass pipe on / off valve 2115 in its flow path.

[0367] The bypass pipe on / off valve 2115 is a valve installed on the bypass pipe 2114. By opening and closing the bypass pipe on / off valve 2115, raw water can be supplied from the water source through the bypass pipe 2114 and the soft water supply pipe 2105 to the water supply outlet 2206.

[0368] The outer shell 2109 is a hollow cylindrical component, and the softening of raw water and the regeneration of ion exchange resin are carried out inside the outer shell 2109.

[0369] like Figure 17 and Figure 18As shown, within the hollow space of the outer casing 2109, a water guiding section 2203, a water softening chamber 2209, a neutralization chamber 2210, and a water delivery section 2204 are sequentially arranged from the side near the central axis I connecting the upper and lower surfaces of the outer casing 2109 towards the outer periphery. A water guiding section inlet 2207 is located at the center of the lower surface of the outer casing 2109, i.e., on the central axis I. A water delivery section outlet 2206 is located at the center of the upper surface of the outer casing 2109, i.e., on the central axis I. The central axis I of the outer casing 2109 coincides with the central axes of the water guiding section 2203, the water softening chamber 2209, the neutralization chamber 2210, and the water delivery section 2204.

[0370] A water guide inlet 2207 is located on the bottom surface of the outer casing 2109 and is used to supply raw water to the water guide section 2203. The central axis of the water guide inlet 2207 is aligned with the central axis I of the outer casing 2109. The water guide inlet 2207 is connected to the raw water supply pipe 2104.

[0371] The water guide section 2203 is a cylindrical component that connects to the water guide section inlet 2207 at its lower end. The water guide section 2203 guides raw water into the water softening device 2100 to supply it to the water softening chamber 2209. The water guide section 2203 can be a pipe or a water-permeable membrane, which has internal space.

[0372] The water guiding section 2203 is configured to ensure that the raw water introduced into the water softening device 2100 flows evenly to the water softening chamber 2209 and the neutralization chamber 2210. Specifically, the water guiding section 2203 is located in the center of the outer casing 2109, and the outer periphery of the water guiding section 2203 is in contact with the water softening chamber 2209. In other words, the water guiding section 2203 is located on the central axis I.

[0373] Furthermore, the water guiding section 2203 extends from the lower part of the water softening chamber 2209 and the neutralization chamber 2210 to the upper part, or more precisely, from the lower end to the upper end. The length of the portion of the water guiding section 2203 that supplies raw water to the water softening chamber 2209 and the neutralization chamber 2210 is equal to the height of the water softening chamber 2209 and the neutralization chamber 2210.

[0374] The water guiding section 2203 has multiple holes on its side surface through which raw water is fed from the central axis I of the outer casing 2109 toward the outer periphery, i.e., toward the water softening chamber 2209. Preferably, the multiple holes are evenly arranged circumferentially on the side surface of the water guiding section 2203. With this structure, the raw water introduced into the device can flow evenly to the water softening chamber 2209 and the neutralization chamber 2210. Therefore, raw water is supplied without leakage to the particles of the weakly acidic cation exchange resin 2213 filled in the water softening chamber 2209 and the particles of the weakly basic anion exchange resin 2214 filled in the neutralization chamber 2210. Thus, the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214 can be utilized efficiently overall.

[0375] The water guiding section 2203 has multiple pores on its side surface that are smaller than the particle size of the weakly acidic cation exchange resin 2213. The lower limit of the particle size of the weakly acidic cation exchange resin 2213 is about 0.3 mm, therefore the diameter of the pores provided on the surface of the water guiding section 2203 is smaller than that. As a result, water permeability is not hindered, and the ion exchange resin is prevented from flowing out of the water softening chamber 2209.

[0376] The water softening chamber 2209 is located within the outer casing 2109, positioned relative to the central axis I of the outer casing 2109 on the outer periphery of the water guiding section 2203. It is a cylindrical space (first space 2211) containing a weakly acidic cation exchange resin 2213. The central axis of the water softening chamber 2209 coincides with the central axis I of the outer casing 2109. The water softening chamber 2209 is connected to the water guiding section 2203 on its inner cylindrical side, to the inner peripheral diaphragm 2215 (a water-permeable cylindrical membrane) on its outer side, and to the cover 2208 on its upper surface. The water softening chamber 2209 is filled with the weakly acidic cation exchange resin 2213 and is equipped with a first electrode 2201.

[0377] The weakly acidic cation exchange resin 2213 is an ion exchange resin having carboxyl groups, such as a resin having a methacrylic acid backbone or a resin having an acrylic acid backbone. In this embodiment, a resin having an acrylic acid backbone is used as the weakly acidic cation exchange resin 2213.

[0378] The first electrode 2201 is an electrode that is not energized during water softening but functions as an anode during the regeneration of the weakly acidic cation exchange resin 2213. The first electrode 2201 is surrounded by the weakly acidic cation exchange resin 2213 within the water softening chamber 2209. Furthermore, "surrounded" here means that the surface of the first electrode 2201 is in contact with the surface of the weakly acidic cation exchange resin 2213 throughout its entire circumference from top to bottom. However, the weakly acidic cation exchange resin 2213 is typically spherical, and a clear flow path for the raw water must be ensured. Therefore, a configuration where the weakly acidic cation exchange resin 2213 is partially in contact with the surface of the first electrode 2201 rather than in a seamless manner is also equivalent to "the first electrode 2201 being surrounded by the weakly acidic cation exchange resin 2213."

[0379] The upper end of the first electrode 2201 is located below the water surface in the water softening chamber 2209 at the beginning of the regeneration process. In addition, multiple first electrodes 2201 (for example, first electrodes 2201a and first electrodes 2201b) are provided in the water softening chamber 2209 in such a way that the distance between adjacent first electrodes 2201 is equal.

[0380] Noble metals or alloys of noble metals can be used as the material for the first electrode 2201. This is because, by containing a noble metal, the first electrode 2201 functions as a catalyst for water electrolysis and will not dissolve even under acidic conditions. Examples of noble metal materials include platinum, iridium, or ruthenium.

[0381] Examples of electrodes include wire electrodes made of noble metal, electrodes with noble metal wires wound around the periphery of a support, and mesh-like noble metal electrodes. Alternatively, a metal rod other than noble metals such as titanium (Ti) can be used as a support and coated with a noble metal. However, if a dissimilar metal interface exists, degradation originating from that interface is likely to occur; therefore, noble metal or noble metal alloy monomers are preferred.

[0382] The inner circumferential diaphragm 2215 is a water-permeable membrane that separates the water softening chamber 2209 and the neutralization chamber 2210, allowing soft water to pass through. The inner circumferential diaphragm 2215 is in contact with the outer surface of the water softening chamber 2209 such that its inner surface covers the outer surface of the water softening chamber 2209. Furthermore, the outer surface of the inner circumferential diaphragm 2215 is in contact with the inner surface of the neutralization chamber 2210 such that it covers the inner surface of the neutralization chamber 2210.

[0383] Thus, the inner circumferential diaphragm 2215 allows the acidic soft water generated in the water softening chamber 2209 to pass through, and separates the water softening chamber 2209 from the neutralization chamber 2210. Furthermore, the term "cover" only needs to be located around the object; it does not need to completely enclose the object.

[0384] Neutralization chamber 2210 is located within outer casing 2109, relative to the central axis I of outer casing 2109, on the outer periphery of water softening chamber 2209. It is a cylindrical space (second space 2212) containing weakly basic anion exchange resin 2214. The central axis of neutralization chamber 2210 coincides with the central axis I of outer casing 2109. Neutralization chamber 2210 is in contact with the outer side of inner peripheral diaphragm 2215 on its inner cylindrical side, and with the inner side of outer peripheral diaphragm 2216, a water-permeable cylindrical membrane, on its outer cylindrical side. Its upper surface is in contact with cover 2208. Neutralization chamber 2210 is filled with weakly basic anion exchange resin 2214 and is provided with a plurality of second electrodes 2202 (e.g., second electrode 2202a and second electrode 2202b are shown).

[0385] The weakly basic anion exchange resin 2214 is an ion exchange resin with tertiary amines and quaternary amines as functional groups. In this embodiment, a resin with a higher proportion of tertiary amines than quaternary amines is used.

[0386] The second electrode 2202 is an electrode that is not energized during the water softening process, but functions as a cathode during the regeneration of the weakly basic anion exchange resin 2214. The second electrode 2202 is surrounded by the weakly basic anion exchange resin 2214 within the neutralization chamber 2210.

[0387] Furthermore, here, "surrounded" means that the surface of the second electrode 2202 is in contact with the surface of the weakly basic anion exchange resin 2214 throughout its entire circumference from top to bottom. However, similar to the weakly acidic cation exchange resin 2213, the weakly basic anion exchange resin 2214 is generally spherical, and it is also necessary to ensure the flow path of the raw water (strictly speaking, acidic soft water). Therefore, the state in which the weakly basic anion exchange resin 2214 is arranged throughout the entire circumference in a partial contact rather than in seamless contact with the surface of the second electrode 2202 is also equivalent to "the second electrode 2202 is surrounded by the weakly basic anion exchange resin 2214".

[0388] The upper end of the second electrode 2202 is located below the water surface in the neutralization chamber 2210 at the beginning of the regeneration process. In addition, multiple second electrodes 2202 are provided, arranged in the neutralization chamber 2210 with equal distances between adjacent second electrodes 2202.

[0389] Noble metals or alloys of noble metals can be used as the material for the second electrode 2202. This is because, by containing noble metals, the second electrode 2202 functions as a catalyst for water electrolysis and will not dissolve even under acidic conditions. Examples of noble metal materials include platinum, iridium, or ruthenium.

[0390] Examples of electrodes include wire electrodes made of noble metal, electrodes with noble metal wires wound around the periphery of a support, and mesh-like noble metal electrodes. Alternatively, a metal rod other than noble metals such as titanium (Ti) can be used as a support and coated with a noble metal. However, if a dissimilar metal interface exists, degradation originating from that interface is likely to occur; therefore, noble metal or noble metal alloy monomers are preferred.

[0391] The first electrode 2201 and the second electrode 2202 are arranged in pairs, and the pair of first electrodes 2201 and second electrodes 2202 are arranged on the same radius of the outer casing 2109.

[0392] Therefore, compared to the case where a pair of electrodes are not on the same radius, the distance between the first electrode 2201 and the second electrode 2202 can be shortened, and the increase in power consumption due to the rise in voltage can be suppressed.

[0393] The water softening device 2100 includes a circuit (including a power supply circuit) for electrode cleaning that connects the first electrode 2201 to the negative electrode and the second electrode 2202 to the positive electrode.

[0394] The outer peripheral diaphragm 2216 is a water-permeable membrane that separates the neutralization chamber 2210 from the water supply section 2204, allowing soft water to pass through. The inner surface of the outer peripheral diaphragm 2216 is in contact with the outer surface of the neutralization chamber 2210, covering it. Similarly, the outer surface of the outer peripheral diaphragm 2216 is in contact with the inner surface of the water supply section 2204, covering it.

[0395] This allows the soft water generated in the neutralization chamber 2210 to pass through, and separates the neutralization chamber 2210 from the water delivery section 2204. Furthermore, the term "covering" only needs to be located around the object; it does not need to completely enclose the object.

[0396] The upper surfaces of the water guiding section 2203, the water softening chamber 2209, the inner peripheral diaphragm 2215, the neutralization chamber 2210, and the outer peripheral diaphragm 2216 are covered by the cover section 2208.

[0397] The cover 2208 is a non-permeable structure, for example, a plate-shaped resin can be used. The cover 2208 is in contact with and covers the upper surfaces of the water guiding section 2203, the water softening chamber 2209, the inner peripheral diaphragm 2215, the neutralization chamber 2210, and the outer peripheral diaphragm 2216, thereby separating the upper surfaces from the water delivery section 2204 described later.

[0398] Therefore, water can be prevented from flowing out of each upper surface into the water delivery section 2204. In other words, the cover 2208 can form a water flow such that the raw water flowing in from the water guide section inlet 2207 passes through the water guide section 2203, the water softening chamber 2209, the inner peripheral diaphragm 2215 and the neutralization chamber 2210 and is then delivered from the side surface of the outer peripheral diaphragm 2216 to the side space 2204a of the water delivery section 2204.

[0399] The water supply unit 2204 supplies soft water from the neutralization chamber 2210 to the water supply outlet 2206, which is located slightly above the upper part of the neutralization chamber 2210. The central axis of the water supply unit 2204 is aligned with the central axis I of the outer casing 2109.

[0400] An exhaust valve 2205 for venting air from the housing 2109 is provided in the water supply section 2204. The water supply section 2204 includes a side space 2204a and an upper space 2204b.

[0401] The side space 2204a is located on the outer periphery of the neutralization chamber 2210 relative to the central axis I of the outer shell 2109, and is a cylindrical space surrounding the neutralization chamber 2210. The side space 2204a is in contact with the outer side of the outer peripheral diaphragm 2216 on its inner cylindrical side and with the inner side of the outer shell 2109 on its outer side. In other words, the side space 2204a is the space located between the inner side of the outer shell 2109 and the outer side of the outer peripheral diaphragm 2216.

[0402] In a direction parallel to the central axis I, the total length of the side space 2204a is longer than the total length of the neutralization chamber 2210. When the bottom surfaces of the side space 2204a and the neutralization chamber 2210 are arranged on the same plane, the top surface of the side space 2204a protrudes upward compared to the top surface of the neutralization chamber 2210.

[0403] The upper space 2204b is a cylindrical space disposed above the top surfaces of the water guiding section 2203, the water softening chamber 2209, the inner peripheral diaphragm 2215, the neutralization chamber 2210, and the outer peripheral diaphragm 2216. The upper space 2204b is in contact with the inner wall of the top surface of the outer shell 2109 on its cylindrical top surface, and with the outer wall of the top surface of the cover 2208 on its cylindrical bottom surface. In addition, the outer cylindrical surface of the upper space 2204b is in contact with the inner surface of the side space 2204a.

[0404] The water outlet 2206 is located on the top surface of the housing 2109 and is used to discharge water from the water supply unit 2204 to the outside of the water softening device 2100. The central axis of the water outlet 2206 is aligned with the central axis I of the housing 2109. The water outlet 2206 is connected to the soft water supply pipe 2105.

[0405] Return to Figure 16 The control unit 2110 controls the execution of each process described below, including the water softening process, regeneration process, drainage process, cleaning process, and electrode cleaning process.

[0406] The control unit 2110 can be implemented as hardware through components and mechanical devices, such as the CPU (Central Processing Unit) of a computer, and as software through computer programs, etc. Therefore, these functional blocks can be implemented in various forms through a combination of hardware and software.

[0407] The control unit 2110 includes an adsorption amount estimation unit 2111, a storage unit 2112, and a timing unit 2113.

[0408] The adsorption capacity estimation unit 2111 uses the total ion concentration of raw water calculated by the raw water conductivity measuring unit 2101, the total ion concentration of soft water calculated by the soft water conductivity measuring unit 2102, and the total flow rate measured by the water volume measuring unit 2103 to calculate the total amount of ions adsorbed on the water softening device 2100.

[0409] The storage unit 2112 stores the information sent to the control unit 2110 and the information calculated in the control unit 2110.

[0410] The timing unit 2113 measures the elapsed time from the start of the regeneration process, and more specifically, measures the elapsed time from the start of energizing the first electrode 2201 and the second electrode 2202.

[0411] The above describes the structure of the water softening device 2100.

[0412] Next, use Figure 19 and Figure 20 The processes performed by the water softening device 2100 (water softening process, regeneration process, drainage process, cleaning process, and electrode cleaning process) are described.

[0413] Figure 19 It is a diagram containing formulas that represent the principle of the water softening device of embodiment 8. Figure 20 This is a graph showing the change in the proportion of hydrogen ions consumed by the weakly acidic cation exchange resin over time during the regeneration process.

[0414] First, the operation of the water softening device 2100 and the principle of the water softening process will be explained.

[0415] like Figure 17 and Figure 18 As shown, in the water softening device 2100, raw water flows from the outside into the lower part of the water guide section 2203 through the water guide section inlet 2207. The incoming raw water is conveyed from the lower part to the upper part of the water guide section 2203 and flows out radially towards the outer casing 2109 through the holes provided in the side wall of the water guide section 2203. That is, the raw water is sent out into the water softening chamber 2209 through the holes of the water guide section 2203.

[0416] The raw water sent to the water softening chamber 2209 is softened by the weakly acidic cation exchange resin 2213 filled inside the water softening chamber 2209. Specifically, the hardness components (calcium ions or magnesium ions) in the raw water exchange with the hydrogen ions adsorbed on the weakly acidic cation exchange resin 2213, resulting in acidic soft water containing hydrogen ions.

[0417] The acidic soft water generated in the water softening chamber 2209 is neutralized by flowing into the neutralization chamber 2210 through the inner peripheral membrane 2215, which serves as a permeable membrane. Specifically, hydrogen ions in the soft water are removed by adsorption onto the weakly basic anion exchange resin 2214, thereby generating neutral soft water (neutralized soft water). Furthermore, during this neutralization reaction, anions such as sulfate ions contained in the soft water are also adsorbed onto the weakly basic anion exchange resin 2214.

[0418] The neutralized soft water generated in the neutralization chamber 2210 flows into the water supply section 2204 through the peripheral diaphragm 2216, which serves as a permeable membrane.

[0419] The soft water flowing into the water delivery section 2204 becomes an upward flow, rising within the side space 2204a of the water delivery section 2204 and flowing into the upper space 2204b of the water delivery section 2204. The soft water flowing into the upper space 2204b flows towards its center within the upper space 2204b and is taken out from the water delivery outlet 2206 located at the center of the upper surface of the water softening device 2100.

[0420] In the water softening process, the raw water is softened in this way.

[0421] During water softening, if the adsorption capacity of cations (more specifically, calcium or magnesium ions, i.e., hardness ions) on the weakly acidic cation exchange resin 2213 or the adsorption capacity of anions on the weakly basic anion exchange resin 2214 increases, the resin performance of the water softening process will decrease. Therefore, a regeneration process is required.

[0422] During the regeneration process, firstly, raw water flows from the raw water supply source into the water guide section 2203 via the water guide inlet 2207, and the incoming raw water is transported to the water softening chamber 2209 and the neutralization chamber 2210. Next, each electrode is energized such that the potential of the first electrode 2201, which is surrounded by the weakly acidic cation exchange resin 2213, is higher than the potential of the second electrode 2202, which is surrounded by the weakly basic anion exchange resin 2214.

[0423] Therefore, a reaction that generates hydrogen ions occurs at the first electrode 2201, which serves as the anode (see reference). Figure 19 Equation (25) shows that a reaction to generate hydroxide ions occurs at the second electrode 2202, which serves as the cathode (see formula (25)). Figure 19 Formula (26)). In other words, hydrogen ions are generated in the water softening chamber 2209 and hydroxide ions are generated in the neutralization chamber 2210.

[0424] The weakly acidic cation exchange resin 2213, which adsorbs hardness components during the water softening process, is exposed to hydrogen ions, thereby undergoing an exchange reaction between the hardness components and hydrogen ions. This process regenerates the weakly acidic cation exchange resin 2213.

[0425] Furthermore, the weakly basic anion exchange resin 2214, which has adsorbed anions through the water softening process, is exposed to hydroxide ions, thereby undergoing an exchange reaction between the adsorbed anions and hydroxide ions. As a result, the weakly basic anion exchange resin 2214 is regenerated.

[0426] During the regeneration process, the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214 are regenerated in this manner.

[0427] During the regeneration process, the water softening device 2100 sets the regeneration time based on the conductivity of the raw water or softened water before and after water is introduced into the housing 2109, or the amount of water introduced into the housing 2109.

[0428] Specifically, at the start of the water softening process, the raw water conductivity measuring unit 2101 is activated to measure the conductivity of the raw water flowing through the raw water supply pipe 2104. Meanwhile, the softened water conductivity measuring unit 2102 is activated to measure the conductivity of the softened water flowing through the softened water supply pipe 2105. Furthermore, the water volume measuring unit 2103 measures the volume of water flowing through the casing 2109. The measured raw water conductivity, softened water conductivity, and water volume are sent to the control unit 2110 and stored in the storage unit 2112.

[0429] The ions to be removed in water softening chamber 2209 are mainly Mg. 2+ and Ca 2+ The hardness ions to be removed in the neutralization chamber 2210 are mainly HCO3- ions. -Cl - and SO4 2- The anions are adsorbed. Based on the principle of electroneutrality, the molar number of cations adsorbed in the water softening chamber 2209 is equal to the molar number of anions adsorbed in the neutralization chamber 2210. Therefore, the difference between the conductivity measured by the raw water conductivity measuring unit 2101 and the conductivity measured by the softened water conductivity measuring unit 2102 originates from the total amount of Mg and Ca salts removed in the water softening device 2100. Thus, since the conductivity difference represents the concentration of removed ions, it is possible to accurately calculate the adsorption amount, adapting to changes in the quality of the raw and softened water.

[0430] The adsorption capacity estimation unit 2111 estimates the amount of ions adsorbed in the water softening device 2100. Specifically, it calculates the difference between the conductivity of the raw water stored in the storage unit 2112 and the conductivity of the softened water. This difference represents the concentration of ions adsorbed in the water softening device 2100. The adsorption capacity estimation unit 2111 multiplies the ion concentration obtained as the difference by the total flow rate measured by the water volume measuring unit 2103. Thus, the amount of ions adsorbed in the water softening device 2100 during the regeneration process is estimated.

[0431] Here, the current value and energizing time required to regenerate the water softening device 2100 by removing the estimated adsorbed ions will be explained.

[0432] During the regeneration process, 1 mole of H is generated from 1 mole of electrons. + One mole of electrons generates one mole of OH-. - Additionally, in order for 1 mole of hardness ions to be released from the resin, 2 moles of H+ are required. + Therefore, the molar number of ions adsorbed in the water softening chamber 2209 and the H2O required for resin regeneration... + The relationship between current value and time is used Figure 19 Equation (22) represents this.

[0433] The control unit 2110 calculates the number of moles of adsorbed ions estimated by the adsorption amount estimation unit 2111 and Figure 19 Formula (22) is used to determine the current value and energizing time required for the regeneration of weak acid cation exchange resin 2213 and weak base anion exchange resin 2214.

[0434] In the water softening device 2100, it is preferable to vary the applied current value as the regeneration process progresses. The reason for this will be explained.

[0435] As the regeneration process progresses, the ions adsorbed during water softening are released from the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214 into the water, thus gradually increasing the ion concentration in the water. In other words, if the time elapsed from the start of the regeneration process is longer, the conductivity of the water in the water softening device 2100 increases compared to when energization begins, resulting in a decrease in voltage. Conversely, at the start of energization, the voltage is high because the ion concentration in the water softening device 2100 is low. Therefore, if the current value is kept constant from the start of energization, the voltage is high at the start of energization and gradually decreases as the energization time progresses.

[0436] In the final stage of the regeneration process Figure 19 In equations (23) and (24), (R-COO) - )2Ca 2+ and R3-NH + Cl - The concentration decreases, thus slowing down the regeneration rate. As a result, such as... Figure 20 As shown, the consumption ratio of the added hydrogen ions decreases, and the conversion rate decreases. When the consumption ratio is low, even if hydrogen ions or hydroxide ions at a concentration higher than that that the resin can consume are added to the weakly acidic cation exchange resin 2213 or the weakly basic anion exchange resin 2214, they do not react with the ions in the resin. Instead, the added hydrogen ions and hydroxide ions react with each other, thus resulting in a loss.

[0437] In other words, based on the voltage characteristics at the initial stage of the regeneration process described above, when applying current, it is preferable not to immediately increase the current to the current value determined by the adsorption amount estimation unit 2111, but to gradually increase the current. This allows the voltage to be kept low, thus reducing power consumption.

[0438] Furthermore, in the final stage of the regeneration process, it is preferable to gradually reduce the current based on the resin's reactivity characteristics. This suppresses the reaction of excess ions with each other, reduces current waste, and minimizes power consumption.

[0439] In order to perform such a time-varying change in the applied current, a timing unit 2113 is used.

[0440] Storage unit 2112 stores a first reference value that indicates the timing of current change, a second reference value that indicates the current reaches its maximum value, and a third reference value that indicates the current begins to decrease from its maximum value. The first reference value is set to approximately 30 minutes to 1 hour from the start of power-on. The second reference value is set to a time later than the first reference value and 30 minutes to 1 hour earlier than the end of power-on.

[0441] like Figure 19As in equation (22), the current and time required for the regeneration process are determined by the hardness of the adsorbed material. Therefore, if the time from the start of energization to the first reference value and the time from the end of energization to the second reference value are extended, the maximum current value or regeneration time needs to be increased.

[0442] The timing unit 2113 measures the elapsed time from the start of applying current to the first electrode 2201 and the second electrode 2202. When the elapsed time measured by the timing unit 2113 reaches a first reference value, the control unit 2110 stops the applied current value from increasing and maintains the current value. Then, when the elapsed time measured by the timing unit 2113 reaches a second reference value, the control unit 2110 decreases the applied current value. Furthermore, the increase in current value from the start of energization to the first reference value, or the decrease in current value from the second reference value to the end of energization, can be linear or stepwise.

[0443] During the regeneration process, during the determined energizing time, a determined current value is applied to the first electrode 2201 and the second electrode 2202 to regenerate the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214.

[0444] As described earlier, during the regeneration process, the concentration of various ions, represented by hardness ions such as calcium or magnesium ions released from the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214, gradually increases over time. In particular, as the concentration of hardness ions increases, Figure 19 In the reaction equation shown in (23), the equilibrium shifts to the left, i.e., towards the direction where the weakly acidic cation exchange resin 2213 re-adsorbs hardness ions. Therefore, in order to regenerate efficiently, it is important to suppress the increase in the calcium ion concentration of the water contained in the shell 2109.

[0445] On the other hand, when the regeneration process is carried out by draining all the water contained in the casing 2109 and supplying raw water to the casing 2109, the ion concentration in the raw water is lower than the ion concentration in the water present in the casing 2109 during the regeneration process, which is disadvantageous for the regeneration process. Therefore, in order for the regeneration process to proceed efficiently, it is preferable not to significantly reduce the total ion concentration in the casing 2109 and thus reduce the concentration of hardness ions. Therefore, a drainage process is performed to drain a portion of the water in the casing 2109.

[0446] During the drainage process, it is important to drain at an appropriate volume. This is to maintain the electrolyte concentration in the water softening chamber 2209 and neutralization chamber 2210 at a certain value (e.g., above the electrolyte concentration of the raw water) while reducing the concentration of hardness ions, thus preparing for a regeneration process after the drainage process, thereby suppressing a decrease in the efficiency of the regeneration process.

[0447] Here, the amount of water discharged during the drainage process is preferably smaller than the sum of the volumes of the water guiding section 2203, the water softening chamber 2209, and the neutralization chamber 2210. More preferably, it is smaller than the sum of the volume excluding the portion occupied by the weakly acidic cation exchange resin 2213 in the water softening chamber 2209 and the volume excluding the portion occupied by the weakly basic anion exchange resin 2214 in the neutralization chamber 2210. Furthermore, it is preferable to have a larger volume excluding the portion occupied by the weakly acidic cation exchange resin 2213 in the water softening chamber 2209.

[0448] Here, use Figure 21 and Figure 22 Specific numerical examples are provided to illustrate the drainage process in detail.

[0449] Figure 21 It is shown that... Figure 17 A diagram showing an example of a larger volume compared to the water guiding section 2203, the water softening chamber 2209, and the neutralization chamber 2210.

[0450] Specifically, Figure 21 The volumes of the water guiding section 2203, the water softening chamber 2209, and the neutralization chamber 2210 are approximately 900 mL, 1300 mL, and 1600 mL, respectively.

[0451] Figure 22 It is shown Figure 21 The example is a graph showing the relationship between the amount of wastewater discharged after a 1-hour regeneration process and the hardness contained in the wastewater.

[0452] exist Figure 21 and Figure 22In the example shown, an equal amount of hard water (hardness: 300 mg / L) was added after drainage. Furthermore, the volumes of the water softening chamber 2209 and the neutralization chamber 2210 are as described above. However, in reality, the water softening chamber 2209 is filled with a weakly acidic cation exchange resin 2213, and the neutralization chamber 2210 is filled with a weakly basic anion exchange resin 2214. Therefore, the amount of water filling the water softening chamber 2209 and the neutralization chamber 2210 is less than their respective volumes. That is, water exists only in the areas outside the spaces occupied by the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214. Experiments have confirmed that the amount of water filling each space is approximately one-third of the volume of the water softening chamber 2209 or the neutralization chamber 2210.

[0453] Therefore, in Figure 21 In the example, corresponding to the volume of 1300 mL in the water softening chamber 2209, there is approximately 400 mL of water in the water softening chamber 2209, and corresponding to the volume of 1600 mL in the neutralization chamber 2210, there is approximately 500 mL of water in the neutralization chamber 2210.

[0454] according to Figure 22 The hardness of the wastewater is highest when the discharge volume is around 550 mL. Even at a discharge volume of 820 mL, the hardness of the wastewater is more than twice that of the injected water with a hardness of 300 mg / L. Therefore, if the discharge volume during the drainage process is within this range, the hardness during regeneration can be reduced efficiently. In other words, if the discharge volume during the drainage process is larger than the volume occupied by the weakly acidic cation exchange resin 2213 in the water softening chamber 2209, the ion concentration in the water softening chamber 2209 can be reduced efficiently, which is preferred. Furthermore, if the discharge volume is larger than the sum of the volumes occupied by the weakly acidic cation exchange resin 2213 in the water softening chamber 2209 and the weakly basic anion exchange resin 2214 in the neutralization chamber 2210, the ion concentration in both the water softening chamber 2209 and the neutralization chamber 2210 can be reduced efficiently, which is also preferred.

[0455] according to Figure 22 It is known that even when the drainage volume exceeds 1600 mL, the hardness is still higher than the injected water hardness of 300 mg / L. Therefore, even when the drainage volume is greater than the volume of the water softening chamber 2209, the hardness during regeneration can be reduced efficiently. However, it is preferable that the maximum drainage volume during the drainage process is smaller than the sum of the volumes of the water softening chamber 2209 and the neutralization chamber 2210.

[0456] Here, return to Figure 16 The specific flow path during the drainage process is explained.

[0457] During the regeneration process, both the drain pipe on / off valve 2108 and the bypass pipe on / off valve 2115 are closed. At the start of the drainage process, the drain pipe on / off valve 2108 is connected to the drain pipe 2107 and the water guide 2203, and the bypass pipe on / off valve 2115 is opened. This allows raw water to be injected into the housing 2109.

[0458] At this time, the flow rate for drainage is smaller than that during the water softening process, which allows the water inside the casing 2109 to be discharged without stirring, and is therefore preferred. Furthermore, there are no particular limitations regarding the measurement of the drainage volume; known methods can be used. For example, methods that determine the prescribed drainage volume by measuring the output of the water volume measuring unit 2103, or methods that utilize the output of the timing unit 2113, can be cited.

[0459] Furthermore, the timing of initiating the drainage process can be determined, for example, based on the elapsed time since the start of the regeneration process. Specifically, if the elapsed time since the start of the regeneration process, as measured by the timing unit 2113, exceeds a certain time, the control unit 2110 initiates the drainage process. This reduces the ion concentration of the water within the water softening device 2100, improving the regeneration efficiency during the regeneration process. Moreover, it is preferable to perform the drainage process multiple times during the period until regeneration is complete. This allows the regeneration process to be performed at a low hardness ion concentration, thus improving regeneration efficiency, which is preferable.

[0460] Furthermore, when determining the timing of the drainage process based on the elapsed time from the start of the regeneration process, it is preferable to increase the frequency of the drainage process from the start of the regeneration process to the middle stage of the regeneration process, and decrease the frequency of the drainage process in the latter half of the regeneration process. For example... Figure 20 As shown, the reaction efficiency is high until the middle stage of the regeneration process, resulting in a large change in the desorbed ion concentration over time. On the other hand, the reaction efficiency is low in the latter half of the regeneration process, resulting in a smaller change in the desorbed ion concentration over time. Therefore, the frequency of drainage in the latter half of the regeneration process can be less than that in the middle stage. In other words, it is preferable to extend the time interval between drainage processes as the regeneration process progresses. Considering both suppressing the amount of drainage and reducing reaction hindrance caused by desorbed ions, the drainage interval is preferably about 30 minutes. For example, a drainage process is performed every 20 minutes until the middle stage of the regeneration process, and every 40 minutes in the latter half of the regeneration process.

[0461] If drainage is complete, the control unit 2110 closes the drain pipe on / off valve 2108 and the bypass pipe on / off valve 2115. This allows the regeneration process to be executed again.

[0462] Furthermore, the direction of drainage is also important during the drainage process. In the weakly acidic cation exchange resin 2213 of the water softening chamber 2209, the adsorption distribution of hardness components exhibits a bias. Specifically, since the weakly acidic cation exchange resin 2213 on the water guiding section 2203 side is where the raw water initially flows in, it readily adsorbs hardness components. On the other hand, the weakly acidic cation exchange resin 2213 on the inner circumferential diaphragm 2215 side is located downstream of the weakly acidic cation exchange resin 2213 on the water guiding section 2203 side, and therefore tends to adsorb less hardness components compared to the weakly acidic cation exchange resin 2213 on the water guiding section 2203 side.

[0463] During regeneration, protons are supplied to the weakly acidic cation exchange resin 2213 in this state for regeneration. During this regeneration, the adsorbed hardness components are released from the weakly acidic cation exchange resin 2213. Therefore, within the water softening chamber 2209, more hardness components are released on the water guiding section 2203 side compared to the inner circumferential diaphragm side, resulting in water with a high concentration of hardness components located on the water guiding section 2203 side within the water softening chamber 2209. Thus, during drainage, by discharging water from the water guiding section 2203 side of the water softening chamber 2209, the concentration of hardness components within the water softening chamber 2209 can be reduced with minimal drainage.

[0464] Furthermore, assuming that during the drainage process, the water in the water softening chamber 2209 is sequentially passed through the inner peripheral diaphragm 2215, the neutralization chamber 2210, and then transported to the outside from the water supply section 2204, similar to the water softening process, the hardness components desorbed from the weakly acidic cation exchange resin 2213 during the regeneration process may be re-adsorbed onto the weakly acidic cation exchange resin 2213. The reasons for this will be explained in detail.

[0465] As described above, the weakly acidic cation exchange resin 2213 on the inner circumferential diaphragm 2215 side tends to adsorb less hardness components and release less hardness components during regeneration compared to the weakly acidic cation exchange resin 2213 on the water-conducting section 2203 side. Under these conditions, if water passes sequentially through the inner circumferential diaphragm 2215 and the neutralization chamber 2210, water from the water-conducting section 2203 side, containing a relatively higher content of hardness components, flows into the inner circumferential diaphragm 2215 side, which contains a relatively lower content of hardness components, potentially re-adsorbing onto the weakly acidic cation exchange resin 2213 on the inner circumferential diaphragm 2215 side. Therefore, from the viewpoint of improving regeneration efficiency, it is preferable that the drainage direction is not in the order of water guide section 2203, water softening chamber 2209, inner peripheral diaphragm 2215, neutralization chamber 2210, and water supply section 2204, but rather in the order of water supply section 2204, neutralization chamber 2210, inner peripheral diaphragm 2215, water softening chamber 2209, and water guide section 2203. That is, when draining through the drainage process, the water inside the outer casing 2109 is preferably discharged from the water guide section 2203 via the drainage pipe 2107. In addition, raw water is preferably supplied to the outer casing 2109 from the water supply section outlet 2206 via the bypass pipe 2114.

[0466] After the drainage process is completed, the process is transferred to the regeneration process again, or the regeneration process is terminated when the regeneration is sufficient.

[0467] After the regeneration process, ions released from the weakly acidic cation exchange resin 2213 and the weakly basic anion exchange resin 2214 are present at high concentrations in the water softening chamber 2209 and the neutralization chamber 2210. Therefore, a cleaning operation is required within the water softening device 2100. If the cleaning is insufficient, residual ions will mix into the water during the water softening process, potentially leading to incomplete water softening. Therefore, a cleaning process is performed after the regeneration process.

[0468] During the cleaning process, in the water softening device 2100, the soft water supply pipe on / off valve 2106 is closed, while the bypass pipe on / off valve 2115 and the drain pipe on / off valve 2108 are opened. As a result, water in the water softening chamber 2209 and the neutralization chamber 2210 is discharged outside the water softening device 2100 via the drain pipe 2107. Meanwhile, raw water flows in from the bypass pipe 2114 through the water supply section 2204, thus creating a state where the water softening process can take place.

[0469] When the end of the cleaning process is determined by time, it is preferable that the time from the start to the end of the cleaning process, i.e., the cleaning time, is set longer than the residence time, i.e., the time from the time the raw water flows into the neutralization chamber 2210 to the time the raw water flows out of the water softening chamber 2209. This allows the water containing a large number of desorbed hardness ions present in the water softening chamber 2209 to be discharged, and the water in the water softening chamber 2209 to be replaced with raw water.

[0470] During the regeneration process, solid calcium carbonate adheres to the electrode surface of the second electrode 2202. If the amount of calcium carbonate deposited on the electrode surface increases, problems such as increased voltage when energized and difficulty in removing calcium carbonate from the electrode surface arise. Therefore, it is preferable to periodically perform an electrode cleaning process to remove calcium carbonate from the cathode surface.

[0471] During the electrode cleaning process, the first electrode 2201 is connected to the negative electrode, and the second electrode 2202 is connected to the positive electrode, meaning the polarity of the electrodes is reversed relative to the regeneration process. This operation generates H2O from the second electrode 2202. + Calcium carbonate on the surface of the second electrode 2202 reacts with H + Dissolves through reaction. Electrode cleaning can be performed during regeneration or after the regeneration process has ended.

[0472] As described above, in the water softening device 2100, the softening of raw water by the water softening process and the maintenance of the water softening device 2100 by the regeneration process, the drainage process, the cleaning process and the electrode cleaning process are repeatedly performed.

[0473] (Effects, etc.)

[0474] The water softening device 2100 according to this embodiment can provide the following effects.

[0475] (1) The water softening device 2100 includes: a water softening chamber 2209 having a weakly acidic cation exchange resin 2213 to generate soft water from raw water containing hardness components; a neutralization chamber 2210 located on the outer periphery of the water softening chamber 2209 having a weakly basic anion exchange resin 2214 to neutralize the soft water; an inner periphery diaphragm 2215 that separates the water softening chamber 2209 and the neutralization chamber 2210 in a manner that allows soft water to pass through; a water guiding section 2203 located on the inner periphery of the water softening chamber 2209 to supply raw water to the water softening chamber 2209; a water delivery section 2204 that delivers the neutralized soft water generated in the neutralization chamber 2210 to the outside; and a control section 2110 that controls the regeneration of the weakly acidic cation exchange resin 2213. The control unit 2110 performs the following processes: a water softening process, in which raw water flows in from the water guide section 2203 and sequentially passes through the water softening chamber 2209, the inner peripheral diaphragm 2215, and the neutralization chamber 2210, thereby obtaining neutralized soft water; a regeneration process, in which, after performing the water softening process for a specified period, water electrolysis is performed, and the generated hydrogen ions are used to regenerate the weakly acidic cation exchange resin 2213; and a cleaning process, in which cations released from the weakly acidic cation exchange resin 2213 during the regeneration process are discharged from the water softening chamber 2209, and anions released from the weakly basic anion exchange resin 2214 are discharged from the neutralization chamber 2210. During the drainage process, water containing cations is discharged from the water guide section 2203.

[0476] With this structure, water can be drained from the side of the weakly acidic cation exchange resin 2213, which has a high concentration of hardness components. Therefore, the re-adsorption of cations to the weakly acidic cation exchange resin 2213 can be suppressed during the cleaning process, enabling a water softening device 2100 that improves regeneration efficiency.

[0477] (2) In the water softening device 2100, the drainage volume during the drainage process is set to be smaller than the sum of the volumes of the water guiding section 2203, the water softening chamber 2209, and the neutralization chamber 2210. If such a drainage volume is set, the drainage that is required during the drainage process can be suppressed, and a water softening device 2100 with a small wastewater volume can be realized.

[0478] (3) In the water softening device 2100, a weakly acidic cation exchange resin 2213 is filled in the water softening chamber 2209, and a weakly basic anion exchange resin 2214 is filled in the neutralization chamber 2210. Preferably, the drainage volume during the drainage process is smaller than the sum of the volume excluding the portion occupied by the weakly acidic cation exchange resin 2213 in the water softening chamber 2209 and the volume excluding the portion occupied by the weakly basic anion exchange resin 2214 in the neutralization chamber 2210.

[0479] By setting the drainage volume to this level, water can be discharged from the water softening chamber 2209 and the neutralization chamber 2210. Therefore, during the regeneration process, cations desorbed from the weakly acidic cation exchange resin 2213 and anions desorbed from the weakly basic anion exchange resin 2214 can be discharged outside the water softening device 2100. Consequently, the residue of cations and anions in the water softening chamber 2209 can be suppressed during the next water softening process, reducing the possibility of hardness precipitation.

[0480] (4) In the water softening device 2100, the volume of water discharged during the drainage process is greater than the volume outside the portion occupied by the weak acid cation exchange resin 2213 in the water softening chamber 2209.

[0481] Therefore, water present in the water softening chamber 2209 can be discharged, ensuring the minimum required drainage volume. Thus, a water softening device 2100 that can suppress drainage volume and improve regeneration efficiency can be realized.

[0482] (5) In the water softening device 2100, it is preferable that the control unit 2110 performs the drainage process multiple times during the regeneration process.

[0483] In this way, drainage can be performed multiple times at appropriate times during the regeneration process, which can improve the resin regeneration efficiency.

[0484] (6) The water softening device 2100 further includes: a first electrode 2201, which is disposed in the water softening chamber 2209 surrounded by a weakly acidic cation exchange resin 2213, and functions as an anode during the regeneration of the weakly acidic cation exchange resin 2213; and a second electrode 2202, which is disposed in the neutralization chamber 2210 surrounded by a weakly basic anion exchange resin 2214, and functions as a cathode during the regeneration of the weakly basic anion exchange resin 2214. During the regeneration process, the control unit 2110 applies a voltage between the first electrode 2201 and the second electrode 2202, and determines the execution of the drainage process based on the applied voltage.

[0485] In this way, drainage can be carried out even when the ion concentration in the water softening chamber 2209 is increased, thereby improving the resin regeneration efficiency during the regeneration process.

[0486] (7) In the water softening device 2100, the raw water supplied to the housing 2109 during the drainage process flows in from the water supply section 2204 side.

[0487] In this way, during the drainage process, a water flow can be formed that allows raw water to flow in from the water supply section 2204 and water inside the casing 2109 to be discharged from the water guide section 2203, which can suppress the re-adsorption of cations onto the weakly acidic cation exchange resin 2213.

[0488] The present disclosure has been described above based on the embodiments. These embodiments are illustrative, and those skilled in the art will understand that various modifications can exist in the combination of these constituent elements or processes, and such modifications are also within the scope of the present disclosure.

[0489] (Modified Example)

[0490] In embodiment 8, the timing of starting the drainage process is determined based on the elapsed time since the start of the regeneration process, but it is not limited to this. For example, the execution of the drainage process can also be determined based on the voltage applied between the first electrode and the second electrode during the regeneration process. Even so, the same effect as in embodiment 8 can be obtained.

[0491] The water softening apparatus disclosed herein is useful as a water softening apparatus capable of efficient regeneration.

[0492] (Implementation Method 9)

[0493] In the technology described in Patent Document 1, hardness ions desorbed from the ion exchange resin are re-adsorbed onto the ion exchange resin, which can easily hinder the reaction during resin regeneration. Therefore, in order to remove the desorbed hardness ions, regeneration needs to be performed while water is flowing through it. Due to this water flow operation, there is a problem that the amount of wastewater discharged during resin regeneration increases.

[0494] This disclosure was made in view of the problems existing in the prior art. This disclosure provides a water softening apparatus capable of suppressing drainage during regeneration and enabling efficient regeneration of the resin.

[0495] The water softening apparatus disclosed herein comprises: a water softening chamber having a weakly acidic cation exchange resin for generating soft water from raw water containing hardness components; a neutralization chamber having a weakly basic anion exchange resin for neutralizing the soft water; a diaphragm separating the water softening chamber and the neutralization chamber in a manner that allows soft water to pass through; a water guiding section for introducing raw water from the outside into the water softening chamber; a water delivery section for transporting the neutralized soft water generated in the neutralization chamber to the outside; a first electrode disposed in the water softening chamber surrounded by the weakly acidic cation exchange resin, serving as an anode during the regeneration of the weakly acidic cation exchange resin; and a second electrode disposed in the neutralization chamber surrounded by the weakly basic anion exchange resin, serving as a cathode during the regeneration of the weakly basic anion exchange resin. A water softening chamber, a diaphragm, a neutralization chamber, and a water delivery section are arranged sequentially from a water guide section having a central axis perpendicular to the bottom surface of the water softening chamber to the outer periphery of a circle centered on the central axis. The first electrode is disposed in the water softening chamber at a position deviating from the water guide section.

[0496] According to this disclosure, a water softening apparatus is provided that can suppress drainage during regeneration and enable efficient regeneration of resin.

[0497] The embodiments of this disclosure will now be described with reference to the accompanying drawings. Furthermore, the following embodiments are merely examples embodying this disclosure and are not intended to limit the technical scope of this disclosure. Additionally, the figures described in each embodiment are schematic diagrams, and the ratios of the size and thickness of the constituent elements in each figure may not necessarily reflect actual dimensional ratios.

[0498] Reference Figure 23 , Figure 24 and Figure 25 The water softening apparatus 3100 according to Embodiment 9 of this disclosure will be described.

[0499] Figure 23 This is a schematic diagram showing the structure of the water softening device 3100 according to Embodiment 9 of this disclosure. Figure 24 This is a perspective view showing the structure of the water softening apparatus 3100 according to Embodiment 9 of this disclosure. Figure 25 This is a cross-sectional view showing the structure of the water softening apparatus 3100 according to Embodiment 9 of this disclosure. Furthermore, in Figures 23-25 The various elements of the water softening device 3100 are conceptually shown in the diagram. Additionally, in... Figure 24 In this document, the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214 are omitted.

[0500] The water softening device 3100 is a device that generates neutral soft water from raw water containing hardness components supplied from the outside. Furthermore, the raw water refers to the water (the water to be treated) introduced into the water softening device 3100 from the raw water supply pipe 3104 (described later), such as well water or tap water. The raw water contains hardness components (calcium ions or magnesium ions).

[0501] By using the water softening device 3100 to perform the water softening process, it is possible to obtain neutral soft water with reduced hardness from raw water with high hardness, so that soft water can be used even in areas where the raw water has high hardness.

[0502] Furthermore, after a certain period of water softening, the water softening device 3100 performs a regeneration process, as described later, to regenerate the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214. Details regarding the water softening and regeneration processes will be described later.

[0503] like Figure 23 As shown, the water softening device 3100 includes a raw water supply pipe 3104, a housing 3109, a soft water supply pipe 3105, a drain pipe 3107, and a control unit 3110.

[0504] The raw water supply pipe 3104 is a pipe that connects the water source such as tap water to the water inlet 3207 described later, and has a raw water conductivity measuring unit 3101 in its flow path.

[0505] The raw water conductivity measuring unit 3101 calculates the total ion concentration of the raw water flowing into the raw water supply pipe 3104. The calculated total ion concentration information of the raw water is sent to the control unit 3110.

[0506] The outer shell 3109 is a hollow cylindrical component, and the softening of raw water and the regeneration of ion exchange resin are carried out inside the outer shell 3109.

[0507] like Figure 24 and Figure 25 As shown, within the hollow space of the outer casing 3109, a water guiding section 3203, a water softening chamber 3209, a neutralization chamber 3210, and a water delivery section 3204 are sequentially arranged from the side near the central axis I connecting the upper and lower surfaces of the outer casing 3109 towards the outer periphery. A water guiding section inlet 3207 is located at the center of the lower surface of the outer casing 3109, i.e., on the central axis I. A water delivery section outlet 3206 is located at the center of the upper surface of the outer casing 3109, i.e., on the central axis I. The central axis I of the outer casing 3109 coincides with the central axes of the water guiding section 3203, the water softening chamber 3209, the neutralization chamber 3210, and the water delivery section 3204. Furthermore, the central axis I is perpendicular to the bottom surface of the water softening chamber 3209.

[0508] A water guide inlet 3207 is located on the bottom surface of the housing 3109 and is used to supply raw water to the water guide section 3203. The central axis of the water guide inlet 3207 is aligned with the central axis I of the housing 3109. The water guide inlet 3207 is connected to the raw water supply pipe 3104.

[0509] The water guide section 3203 is a cylindrical component that connects to the water guide section inlet 3207 at its lower end. The water guide section 3203 guides raw water into the water softening device 3100 to supply it to the water softening chamber 3209. As the water guide section 3203, pipes or other pipes with internal space can be used.

[0510] The water guiding section 3203 is configured to ensure that the raw water introduced into the water softening device 3100 flows evenly to the water softening chamber 3209 and the neutralization chamber 3210. Specifically, the water guiding section 3203 is located in the center of the housing 3109, and the outer periphery of the water guiding section 3203 is in contact with the water softening chamber 3209. In other words, the water guiding section 3203 is located on the central axis I.

[0511] Furthermore, the water guiding section 3203 extends from the lower part of the water softening chamber 3209 and the neutralization chamber 3210 to the upper part, or more precisely, from the lower end to the upper end. The length of the portion of the water guiding section 3203 that supplies raw water to the water softening chamber 3209 and the neutralization chamber 3210 is equal to the height of the water softening chamber 3209 and the neutralization chamber 3210.

[0512] The water guiding section 3203 has multiple holes on its side surface through which raw water is fed from the central axis I of the outer casing 3109 toward the outer periphery, i.e., toward the water softening chamber 3209. Preferably, the multiple holes are evenly arranged circumferentially on the side surface of the water guiding section 3203. With this structure, the raw water introduced into the device can flow evenly to the water softening chamber 3209 and the neutralization chamber 3210. Therefore, raw water is supplied without leakage to the particles of the weakly acidic cation exchange resin 3213 filled in the water softening chamber 3209 and the particles of the weakly basic anion exchange resin 3214 filled in the neutralization chamber 3210. Thus, the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214 can be utilized efficiently overall.

[0513] The water guiding section 3203 has multiple pores on its side surface that are smaller than the particle size of the weakly acidic cation exchange resin 3213. The lower limit of the particle size of the weakly acidic cation exchange resin 3213 is about 0.3 mm, therefore the diameter of the pores provided on the surface of the water guiding section 3203 is smaller than that. As a result, water permeability is not hindered, and the ion exchange resin is prevented from flowing out of the water softening chamber 3209.

[0514] The water softening chamber 3209 is located within the outer casing 3109, positioned relative to the central axis I of the outer casing 3109 on the outer periphery of the water guiding section 3203. It is a cylindrical space (first space 3211) containing a weakly acidic cation exchange resin 3213. The central axis of the water softening chamber 3209 coincides with the central axis I of the outer casing 3109. The water softening chamber 3209 is connected to the water guiding section 3203 on its inner cylindrical side, to a water-permeable cylindrical membrane (inner peripheral diaphragm 3215) on its outer side, and to a cover 3208 on its upper surface. The water softening chamber 3209 is filled with the weakly acidic cation exchange resin 3213 and is equipped with a first electrode 3201.

[0515] The weakly acidic cation exchange resin 3213 is an ion exchange resin having carboxyl groups, such as a resin having a methacrylic acid backbone or a resin having an acrylic acid backbone. In this embodiment, a resin having an acrylic acid backbone is used as the weakly acidic cation exchange resin 3213.

[0516] The first electrode 3201 is an electrode that is not energized during water softening but functions as an anode during the regeneration of the weakly acidic cation exchange resin 3213. The first electrode 3201 is surrounded by the weakly acidic cation exchange resin 3213 within the water softening chamber 3209. Furthermore, "surrounded" here means that the surface of the first electrode 3201 is in contact with the surface of the weakly acidic cation exchange resin 3213 throughout its entire circumference from top to bottom. However, the weakly acidic cation exchange resin 3213 is typically spherical, and a clear flow path for the raw water must be ensured. Therefore, a configuration where the weakly acidic cation exchange resin 3213 is partially in contact with the surface of the first electrode 3201 rather than in a seamless manner is also equivalent to "the first electrode 3201 being surrounded by the weakly acidic cation exchange resin 3213."

[0517] The upper end of the first electrode 3201 is located below the water surface in the water softening chamber 3209 at the beginning of the regeneration process. In addition, multiple first electrodes 3201 are provided (for example, first electrodes 3201a and first electrodes 3201b), which are arranged in the water softening chamber 3209 with equal distances between adjacent first electrodes 3201.

[0518] Noble metals or alloys of noble metals can be used as the material for the first electrode 3201. This is because, by containing a noble metal, the first electrode 3201 functions as a catalyst for water electrolysis and will not dissolve even under acidic conditions. Examples of noble metal materials include platinum, iridium, or ruthenium.

[0519] Examples of electrodes include wire electrodes made of noble metal, electrodes with noble metal wires wound around the periphery of a support, and mesh-like noble metal electrodes. Alternatively, a metal rod other than noble metals such as titanium (Ti) can be used as a support and coated with a noble metal. However, if a dissimilar metal interface exists, degradation originating from that interface is likely to occur; therefore, noble metal or noble metal alloy monomers are preferred.

[0520] The inner circumferential diaphragm 3215 is a water-permeable membrane that separates the water softening chamber 3209 and the neutralization chamber 3210, allowing soft water to pass through. The inner circumferential diaphragm 3215 is in contact with the outer surface of the water softening chamber 3209 such that its inner surface covers the outer surface of the water softening chamber 3209. Furthermore, the outer surface of the inner circumferential diaphragm 3215 is in contact with the inner surface of the neutralization chamber 3210 such that it covers the inner surface of the neutralization chamber 3210.

[0521] Thus, the inner circumferential diaphragm 3215 allows the acidic soft water generated in the water softening chamber 3209 to pass through, and separates the water softening chamber 3209 from the neutralization chamber 3210. Furthermore, the term "cover" only needs to be located around the object; it does not need to completely enclose the object.

[0522] Neutralization chamber 3210 is located within housing 3109, positioned relative to the central axis I of housing 3109 on the outer periphery of water softening chamber 3209. It is a cylindrical space (second space 3212) containing weakly basic anion exchange resin 3214. The central axis of neutralization chamber 3210 coincides with the central axis I of housing 3109. Neutralization chamber 3210 is in contact with the outer side of inner peripheral diaphragm 3215 on its cylindrical inner side and with the inner side of outer peripheral diaphragm 3216, a water-permeable cylindrical membrane, on its outer outer side. Its upper surface is in contact with cover 3208. Neutralization chamber 3210 is filled with weakly basic anion exchange resin 3214 and is provided with a plurality of second electrodes 3202 (e.g., second electrode 3202a and second electrode 3202b are shown).

[0523] The weakly basic anion exchange resin 3214 is an ion exchange resin with tertiary amines and quaternary amines as functional groups. In this embodiment, a resin with a higher proportion of tertiary amines than quaternary amines is used.

[0524] The second electrode 3202 is an electrode that is not energized during the water softening process, but functions as a cathode during the regeneration of the weakly basic anion exchange resin 3214. The second electrode 3202 is surrounded by the weakly basic anion exchange resin 3214 within the neutralization chamber 3210.

[0525] Furthermore, here, "surrounded" means that the surface of the second electrode 3202 is in contact with the surface of the weakly basic anion exchange resin 3214 throughout its entire circumference from top to bottom. However, similar to the weakly acidic cation exchange resin 3213, the weakly basic anion exchange resin 3214 is generally spherical, and it is also necessary to ensure the flow path of the raw water (strictly speaking, acidic soft water). Therefore, the state in which the weakly basic anion exchange resin 3214 is arranged throughout the entire circumference in a partial contact rather than in a seamless contact with the surface of the second electrode 3202 is also equivalent to "the second electrode 3202 is surrounded by the weakly basic anion exchange resin 3214".

[0526] The upper end of the second electrode 3202 is located below the water surface in the neutralization chamber 3210 at the beginning of the regeneration process. In addition, multiple second electrodes 3202 are provided, arranged in the neutralization chamber 3210 with equal distances between adjacent second electrodes 3202.

[0527] Noble metals or alloys of noble metals can be used as the material for the second electrode 3202. This is because, by containing a noble metal, the second electrode 3202 functions as a catalyst for water electrolysis and will not dissolve even under acidic conditions. Examples of noble metal materials include platinum, iridium, or ruthenium.

[0528] Examples of electrodes include wire electrodes made of noble metal, electrodes with noble metal wires wound around the periphery of a support, and mesh-like noble metal electrodes. Alternatively, a metal rod other than noble metals such as titanium (Ti) can be used as a support and coated with a noble metal. However, if a dissimilar metal interface exists, degradation originating from that interface is likely to occur; therefore, noble metal or noble metal alloy monomers are preferred.

[0529] The details of the configuration of the first electrode 3201 and the second electrode 3202 will be described later.

[0530] The water softening device 3100 includes a circuit (including a power supply circuit) for electrode cleaning, which connects the first electrode 3201 to the negative electrode and the second electrode 3202 to the positive electrode.

[0531] The outer peripheral diaphragm 3216 is a water-permeable membrane that separates the neutralization chamber 3210 from the water supply section 3204, allowing soft water to pass through. The inner surface of the outer peripheral diaphragm 3216 is in contact with the outer surface of the neutralization chamber 3210, covering it. Similarly, the outer surface of the outer peripheral diaphragm 3216 is in contact with the inner surface of the water supply section 3204, covering it.

[0532] This allows the soft water generated in the neutralization chamber 3210 to pass through, and separates the neutralization chamber 3210 from the water delivery section 3204. Furthermore, the term "covering" only needs to be around the object; it does not need to completely enclose the object.

[0533] The upper surfaces of the water guiding section 3203, the water softening chamber 3209, the inner peripheral diaphragm 3215, the neutralization chamber 3210, and the outer peripheral diaphragm 3216 are covered by the cover section 3208.

[0534] The cover 3208 is a non-permeable structure, for example, a plate-shaped resin can be used. The cover 3208 is in contact with and covers the upper surfaces of the water guiding part 3203, the water softening chamber 3209, the inner peripheral diaphragm 3215, the neutralization chamber 3210, and the outer peripheral diaphragm 3216, thereby separating the upper surfaces from the water delivery part 3204 described later.

[0535] Therefore, water can be prevented from flowing out of each upper surface into the water delivery section 3204. In other words, the cover 3208 can form a water flow such that the raw water flowing in from the water guide section inlet 3207 passes through the water guide section 3203, the water softening chamber 3209, the inner peripheral diaphragm 3215 and the neutralization chamber 3210 and is then delivered from the side surface of the outer peripheral diaphragm 3216 to the side space 3204a of the water delivery section 3204.

[0536] The water delivery unit 3204 delivers soft water from the neutralization chamber 3210 to the water delivery outlet 3206, which is located slightly above the upper part of the neutralization chamber 3210. The central axis of the water delivery unit 3204 is aligned with the central axis I of the outer casing 3109.

[0537] An exhaust valve 3205 for venting air from the housing 3109 is provided in the water supply section 3204. The water supply section 3204 includes a side space 3204a and an upper space 3204b.

[0538] The side space 3204a is located on the outer periphery of the neutralization chamber 3210 relative to the central axis I of the outer shell 3109, and is a cylindrical space surrounding the neutralization chamber 3210. The side space 3204a is in contact with the outer side of the outer peripheral diaphragm 3216 on its inner cylindrical side, and with the inner side of the outer shell 3109 on its outer side. In other words, the side space 3204a is the space located between the inner side of the outer shell 3109 and the outer side of the outer peripheral diaphragm 3216.

[0539] In a direction parallel to the central axis I, the total length of the side space 3204a is longer than the total length of the neutralization chamber 3210. When the bottom surfaces of the side space 3204a and the neutralization chamber 3210 are arranged on the same plane, the top surface of the side space 3204a protrudes upward compared to the top surface of the neutralization chamber 3210.

[0540] The upper space 3204b is a cylindrical space disposed above the top surfaces of the water guiding section 3203, the water softening chamber 3209, the inner peripheral diaphragm 3215, the neutralization chamber 3210, and the outer peripheral diaphragm 3216. The upper space 3204b is in contact with the inner wall of the top surface of the outer shell 3109 on its cylindrical top surface, and with the outer wall of the top surface of the cover 3208 on its cylindrical bottom surface. In addition, the outer cylindrical surface of the upper space 3204b is in contact with the inner surface of the side space 3204a.

[0541] The water outlet 3206 is located on the top surface of the housing 3109 and is used to discharge water from the water supply unit 3204 to the outside of the water softening device 3100. The central axis of the water outlet 3206 is aligned with the central axis I of the housing 3109. The water outlet 3206 is connected to the soft water supply pipe 3105.

[0542] Return to Figure 23The soft water supply pipe 3105 connects the water supply outlet 3206 to the destination of the soft water supply. Its flow path includes a soft water conductivity measuring unit 3102 and a water volume measuring unit 3103. Furthermore, a drain pipe 3107 branches off from the soft water supply pipe 3105 midway through its flow path. A soft water supply pipe on / off valve 3106 is installed on the downstream side of the branch point between the soft water supply pipe 3105 and the drain pipe 3107.

[0543] The soft water conductivity measuring unit 3102 calculates the total ion concentration of the soft water discharged from the water supply outlet 3206. The calculated total ion concentration information of the soft water is sent to the control unit 3110, which will be described later.

[0544] As for the raw water conductivity measuring unit 3101 and the soft water conductivity measuring unit 3102, they can be used without any problems as long as they are devices capable of measuring the resistance of water.

[0545] Drainage pipe 3107 is a branch pipe that extends from soft water supply pipe 3105 upstream of soft water supply pipe on / off valve 3106, and is used for drainage during the regeneration process. Drainage pipe 3107 has a drain pipe on / off valve 3108 in its flow path.

[0546] The water volume measuring unit 3103 is a component that measures the amount of water supplied to the water softening device 3100, and can be equipped with devices such as a water meter that can measure the cumulative water volume. The measured water volume information is sent to the control unit 3110, which will be described later.

[0547] The control unit 3110 controls the execution of each of the following processes: water softening, regeneration, drainage, cleaning, and electrode cleaning.

[0548] The control unit 3110 can be implemented as hardware through components and mechanical devices, such as the CPU (Central Processing Unit) of a computer, and as software through computer programs. Therefore, these functional blocks can be implemented in various forms through a combination of hardware and software.

[0549] The control unit 3110 includes an adsorption amount estimation unit 3111, a storage unit 3112, and a timing unit 3113.

[0550] The adsorption capacity estimation unit 3111 uses the total ion concentration of raw water calculated by the raw water conductivity measuring unit 3101, the total ion concentration of soft water calculated by the soft water conductivity measuring unit 3102, and the total flow rate measured by the water volume measuring unit 3103 to calculate the total amount of ions adsorbed on the water softening device 3100.

[0551] The storage unit 3112 stores the information sent to the control unit 3110 and the information calculated in the control unit 3110.

[0552] The timing unit 3113 measures the elapsed time from the start of the regeneration process, and more specifically, measures the elapsed time from the start of energizing the first electrode 3201 and the second electrode 3202.

[0553] use Figure 26 The positions of the first electrode 3201 and the second electrode 3202 will be described in more detail.

[0554] Figure 26 This is a cross-sectional view showing the positions of the first electrode 3201 and the second electrode 3202 of the water softening device 3100. Figure 25 The cross-sectional view at plane A-A' is shown. Furthermore, plane A-A' is parallel to the bottom surface of the water softening chamber 3209. That is to say, Figure 26 The plane shown is a cross-section parallel to the bottom surface of the water softening chamber 3209.

[0555] Viewed from above, the water guiding section 3203, the water softening chamber 3209, the neutralization chamber 3210, and the water delivery section 3204 are all roughly circular in shape. Therefore, in Figure 26 In the cross-sectional view shown, the sections are circles, and the centers of each circle are approximately the same (point O). A water softening chamber 3209, an inner circumferential diaphragm 3215, a neutralization chamber 3210, and a water delivery section 3204 are arranged sequentially along the outer periphery of the virtual circle X centered at point O. Furthermore, in this embodiment, the outer periphery of the virtual circle X coincides with that of the water delivery section 3204.

[0556] Multiple first electrodes 3201 and second electrodes 3202 are respectively provided. Furthermore, a pair of first electrodes 3201 and second electrodes 3202 are arranged on the same radius of the virtual circle X. Moreover, "on the same radius" means on the radius in the same direction, for example, meaning... Figure 26 On line B. In this embodiment, eight pairs of electrodes are disposed on the same radius (same diameter) of the cylindrical shape of the housing 3109.

[0557] During the water softening process, as described above, the raw water flows sequentially from the water guide section 3203 through the water softening chamber 3209, the neutralization chamber 3210, and the water delivery section 3204 within the water softening device 3100. That is, the raw water flows from the center (point O) of the virtual circle X towards the outer periphery of the virtual circle X.

[0558] Therefore, in the water softening chamber 3209, hardness ions are adsorbed sequentially from the weakly acidic cation exchange resin 3213 near the water guide section 3203, and in the neutralization chamber 3210, hydrogen ions are adsorbed sequentially from the weakly basic anion exchange resin 3214 near the inner peripheral membrane 3215.

[0559] That is, the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214 are from Figure 26 The central side of the cross section is gradually consumed.

[0560] On the other hand, during the regeneration process, hydrogen ions required for the regeneration of the weakly acidic cation exchange resin 3213 are generated from the first electrode 3201, and hydroxide ions required for the regeneration of the weakly basic anion exchange resin 3214 are generated from the second electrode 3202.

[0561] Therefore, by providing the first electrode 3201 and the second electrode 3202 at each location where the ion exchange resin is consumed, the regeneration efficiency of the ion exchange resin during the regeneration process can be improved.

[0562] Here, the first boundary portion 3401, the second boundary portion 3402, the intermediate portion 3403, and the intermediate portion 3404 are defined.

[0563] The first boundary section 3401 is the boundary between the water guiding section 3203 and the water softening chamber 3209.

[0564] The second boundary portion 3402 is the boundary between the neutralization chamber 3210 and the water supply section 3204. In other words, the second boundary portion 3402 is the outer peripheral diaphragm 3216.

[0565] The middle part 3403 is a virtual line in a roughly circular shape centered at point O, which is set at equal distances from the first boundary part 3401 and the inner peripheral diaphragm 3215. The distance from the first boundary part 3401 and the distance from the inner peripheral diaphragm 3215 are equal on the same radius.

[0566] The middle part 3404 is a virtual line in a roughly circular shape centered at point O, and is arranged at equal distances from the inner peripheral diaphragm 3215 and the second boundary part 3402. The distance from the inner peripheral diaphragm 3215 and the distance from the second boundary part 3402 are equal on the same radius.

[0567] The first electrode 3201 is positioned on the same radius of the cross-section of the water softening device 3100, further offset from the water guiding section 3203 than the midpoint between the first boundary portion 3401 and the inner peripheral diaphragm 3215. The first boundary portion 3401 is the boundary between the water guiding section 3203 and the water softening chamber 3209. In other words, on the same radius, the distance between the first electrode 3201 and the first boundary portion 3401 is shorter than the distance between the first electrode 3201 and the inner peripheral diaphragm 3215.

[0568] Furthermore, the second electrode 3202 is positioned on the same radius of the cross-section of the water softening device 3100, further towards the inner circumferential diaphragm 3215 than the midpoint between the second boundary portion 3402 and the inner circumferential diaphragm 3215. The second boundary portion 3402 is the boundary between the neutralization chamber 3210 and the water supply section 3204. In other words, on the same radius, the distance between the second electrode 3202 and the inner circumferential diaphragm 3215 is shorter than the distance between the second electrode 3202 and the second boundary portion 3402.

[0569] By configuring it in this way, the hydrogen or hydroxide ions required for regeneration can be directly supplied near areas where the ion exchange resin is consumed to a high degree, thereby improving the regeneration efficiency during the regeneration process.

[0570] Furthermore, the first electrode 3201 can be positioned without particular limitation as long as it is closer to the center than the middle portion 3403 between the first boundary portion 3401 and the inner peripheral diaphragm 3215. Similarly, the second electrode 3202 can be positioned without particular limitation as long as it is closer to the center than the middle portion 3404 between the inner peripheral diaphragm 3215 and the second boundary portion 3402. However, the smaller the distance between the pair of first electrodes 3201 and second electrodes 3202, the lower the voltage applied between the first electrodes 3201 and the second electrodes 3202, and the lower the power consumption. Therefore, from the viewpoint of reducing power consumption, it is preferable to make the first electrode 3201 and the second electrode 3202 close together. Alternatively, the first electrode 3201 and the second electrode 3202 may be configured such that the ratio of the distance from the water guide portion 3203 to the first electrode 3201 to the first distance from the first boundary portion 3401 to the inner peripheral diaphragm 3215 is equal to the ratio of the distance from the inner peripheral diaphragm 3215 to the second electrode 3202 to the second distance from the inner peripheral diaphragm 3215 to the second boundary portion 3402.

[0571] The above describes the structure of the water softening device 3100.

[0572] Next, use Figure 27 and Figure 28 The processes performed by the water softening device 3100 (water softening process, regeneration process, cleaning process, and electrode cleaning process) are described.

[0573] Figure 27 It is a diagram containing formulas that represent the principle of the water softening device 3100 in Embodiment 9. Figure 28 This is a graph showing the change in the proportion of hydrogen ions consumed by the weakly acidic cation exchange resin over time during the regeneration process.

[0574] First, the operation of the water softening device 3100 and the principle of the water softening process will be explained.

[0575] like Figure 24 and Figure 25 As shown, in the water softening device 3100, raw water flows from the outside into the lower part of the water guide section 3203 through the water guide section inlet 3207. The incoming raw water is conveyed from the lower part to the upper part of the water guide section 3203 and flows out radially towards the outer casing 3109 through the holes provided in the side wall of the water guide section 3203. That is, the raw water is sent out into the water softening chamber 3209 through the holes of the water guide section 3203.

[0576] The raw water sent to the water softening chamber 3209 is softened by the weakly acidic cation exchange resin 3213 filled inside the water softening chamber 3209. Specifically, the hardness components (calcium ions or magnesium ions) in the raw water exchange with the hydrogen ions adsorbed on the weakly acidic cation exchange resin 3213, resulting in acidic soft water containing hydrogen ions.

[0577] The acidic soft water generated in the water softening chamber 3209 is neutralized by flowing into the neutralization chamber 3210 through the inner peripheral membrane 3215, which serves as a permeable membrane. Specifically, hydrogen ions in the soft water are removed by adsorption onto the weakly basic anion exchange resin 3214, thereby generating neutral soft water (neutralized soft water). Furthermore, during this neutralization reaction, anions such as sulfate ions contained in the soft water are also adsorbed onto the weakly basic anion exchange resin 3214.

[0578] The neutralized soft water generated in the neutralization chamber 3210 flows into the water supply section 3204 through the peripheral diaphragm 3216, which serves as a permeable membrane.

[0579] The soft water flowing into the water delivery section 3204 becomes an upward flow, rising within the side space 3204a of the water delivery section 3204 and flowing into the upper space 3204b of the water delivery section 3204. The soft water flowing into the upper space 3204b flows towards its center within the upper space 3204b and is taken out from the water delivery outlet 3206 located at the center of the upper surface of the water softening device 3100.

[0580] In the water softening process, the raw water is softened in this way.

[0581] During water softening, if the adsorption capacity of cations (more specifically, calcium or magnesium ions, i.e., hardness ions) on the weakly acidic cation exchange resin 3213 or the adsorption capacity of anions on the weakly basic anion exchange resin 3214 increases, the resin performance of the water softening process will decrease. Therefore, a regeneration process is required.

[0582] During the regeneration process, firstly, raw water flows from the raw water supply source into the water guide section 3203 via the water guide inlet 3207, and the incoming raw water is transported to the water softening chamber 3209 and the neutralization chamber 3210. Next, each electrode is energized such that the potential of the first electrode 3201, which is surrounded by a weakly acidic cation exchange resin 3213, is higher than the potential of the second electrode 3202, which is surrounded by a weakly basic anion exchange resin 3214.

[0583] Therefore, a reaction that generates hydrogen ions occurs at the first electrode 3201, which serves as the anode (see reference). Figure 27 Equation (35) occurs at the second electrode 3202, which serves as the cathode, where a reaction to generate hydroxide ions takes place (see formula (35)). Figure 27 Formula (36)). In other words, hydrogen ions are generated in the water softening chamber 3209 and hydroxide ions are generated in the neutralization chamber 3210.

[0584] The weakly acidic cation exchange resin 3213, which adsorbs hardness components during the water softening process, is exposed to hydrogen ions, thereby undergoing an exchange reaction between the hardness components and hydrogen ions. This process regenerates the weakly acidic cation exchange resin 3213.

[0585] Furthermore, the weakly basic anion exchange resin 3214, which has adsorbed anions through the water softening process, is exposed to hydroxide ions, thereby undergoing an exchange reaction between the adsorbed anions and hydroxide ions. As a result, the weakly basic anion exchange resin 3214 is regenerated.

[0586] During the regeneration process, the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214 are regenerated in this manner.

[0587] During the regeneration process, the water softening device 3100 sets the regeneration time based on the conductivity of the raw water or softened water before and after water is introduced into the housing 3109, or the amount of water introduced into the housing 3109.

[0588] Specifically, at the start of the water softening process, the raw water conductivity measuring unit 3101 is activated to measure the conductivity of the raw water flowing through the raw water supply pipe 3104. Meanwhile, the softened water conductivity measuring unit 3102 is activated to measure the conductivity of the softened water flowing through the softened water supply pipe 3105. Furthermore, the water volume measuring unit 3103 measures the water volume flowing through the casing 3109. The measured raw water conductivity, softened water conductivity, and water volume are sent to the control unit 3110 and stored in the storage unit 3112.

[0589] The ions to be removed in water softening chamber 3209 are mainly Mg. 2+ and Ca 2+ The hardness ions to be removed in the neutralization chamber 3210 are mainly HCO3- ions. -Cl - and SO4 2- The anions are adsorbed. Based on the principle of electroneutrality, the molar number of cations adsorbed in the water softening chamber 3209 is equal to the molar number of anions adsorbed in the neutralization chamber 3210. Therefore, the difference between the conductivity measured by the raw water conductivity measuring unit 3101 and the conductivity measured by the softened water conductivity measuring unit 3102 originates from the total amount of Mg and Ca salts removed in the water softening device 3100. Thus, since the conductivity difference represents the concentration of removed ions, it is possible to accurately calculate the adsorption amount, adapting to changes in the water quality of the raw and softened water.

[0590] The adsorption capacity estimation unit 3111 estimates the amount of ions adsorbed in the water softening device 3100. Specifically, it calculates the difference between the conductivity of the raw water stored in the storage unit 3112 and the conductivity of the softened water. This difference represents the concentration of ions adsorbed in the water softening device 3100. The adsorption capacity estimation unit 3111 multiplies the ion concentration obtained as the difference by the total flow rate measured by the water volume measuring unit 3103. Thus, the amount of ions adsorbed in the water softening device 3100 during the regeneration process is estimated.

[0591] Here, use Figure 27 and Figure 28 The current value and energizing time required to regenerate the water softening device 3100 by removing the estimated adsorbed ions are explained.

[0592] During the regeneration process, 1 mole of H is generated from 1 mole of electrons. + One mole of electrons generates one mole of OH-. - Additionally, in order for 1 mole of hardness ions to be released from the resin, 2 moles of H+ are required. + Therefore, the molar number of ions adsorbed in the water softening chamber 3209 and the H2O required for resin regeneration... + The relationship between current value and time is used Figure 27 Equation (32) represents this.

[0593] The control unit 3110 calculates the number of moles of adsorbed ions estimated by the adsorption amount estimation unit 3111 and Figure 27 Formula (32) is used to determine the current value and energizing time required for the regeneration of the weak acid cation exchange resin 3213 and the weak base anion exchange resin 3214.

[0594] In the water softening device 3100, it is preferable to vary the applied current value as the regeneration process progresses. The reason for this will be explained.

[0595] As the regeneration process progresses, the ions adsorbed during water softening are released from the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214 into the water, thus gradually increasing the ion concentration in the water. In other words, if the time elapsed from the start of the regeneration process is longer, the conductivity of the water in the water softening device 3100 increases compared to when energization begins, resulting in a decrease in voltage. Conversely, at the start of energization, the voltage is high because the ion concentration in the water softening device 3100 is low. Therefore, if the current value is kept constant from the start of energization, the voltage is high at the start of energization and gradually decreases as the energization time progresses.

[0596] In the final stage of the regeneration process Figure 27 In equations (33) and (34), (R-COO) - )2Ca 2+ and R3-NH + Cl - The concentration decreases, thus slowing down the regeneration rate. As a result, such as... Figure 28 As shown, the consumption ratio of the added hydrogen ions decreases, and the conversion rate decreases. When the consumption ratio is low, even if hydrogen ions or hydroxide ions at a concentration higher than that that the resin can consume are added to the weakly acidic cation exchange resin 3213 or the weakly basic anion exchange resin 3214, they do not react with the ions in the resin. Instead, the added hydrogen ions and hydroxide ions react with each other, thus resulting in a loss.

[0597] In other words, based on the voltage characteristics at the initial stage of the regeneration process described above, when applying current, it is preferable not to immediately increase the current to the current value determined by the adsorption amount estimation unit 3111, but to gradually increase the current. This allows the voltage to be kept low, thus reducing power consumption.

[0598] Furthermore, in the final stage of the regeneration process, it is preferable to gradually reduce the current based on the resin's reactivity characteristics. This suppresses the reaction of excess ions with each other, reduces current waste, and minimizes power consumption.

[0599] To perform such a time-varying change in the applied current, a timing unit 3113 is used.

[0600] The storage unit 3112 stores a first reference value, which represents the timing of current changes, and a second reference value, which represents the time when the current reaches its maximum value and the time from which it begins to decrease. The first reference value is set to approximately 30 minutes to 1 hour from the start of power-on. The second reference value is set to a time later than the first reference value and 30 minutes to 1 hour earlier than the end of power-on.

[0601] like Figure 27As in equation (32), the current and time required for the regeneration process are determined by the hardness of the adsorbed material. Therefore, if the time from the start of energization to the first reference value and the time from the end of energization to the second reference value are extended, the maximum current value or regeneration time needs to be increased.

[0602] The timing unit 3113 measures the elapsed time from the start of applying current to the first electrode 3201 and the second electrode 3202. When the elapsed time measured by the timing unit 3113 reaches a first reference value, the control unit 3110 stops the applied current value from increasing and maintains the current value. Then, when the elapsed time measured by the timing unit 3113 reaches a second reference value, the control unit 3110 decreases the applied current value. Furthermore, the increase in current value from the start of energization to the first reference value, or the decrease in current value from the second reference value to the end of energization, can be linear or stepwise.

[0603] During the regeneration process, a determined current value is applied to the first electrode 3201 and the second electrode 3202 during the determined energizing time to regenerate the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214.

[0604] After the regeneration process, ions released from the weakly acidic cation exchange resin 3213 and the weakly basic anion exchange resin 3214 are present at high concentrations in the water softening chamber 3209 and the neutralization chamber 3210. Therefore, a cleaning operation is required within the water softening device 3100. If the cleaning is insufficient, residual ions will mix into the water during the water softening process, potentially leading to incomplete water softening. Therefore, a cleaning process is performed after the regeneration process.

[0605] During the cleaning process, in the water softening device 3100, the soft water supply pipe on / off valve 3106 is closed, and the drain pipe on / off valve 3108 is opened, thereby draining the water in the water softening chamber 3209 and the neutralization chamber 3210 out of the water softening device 3100 via the drain pipe 3107. Furthermore, by allowing raw water to flow in from the raw water supply pipe 3104, the device is prepared to restart the regeneration process.

[0606] When the end of the cleaning process is determined by time, the cleaning time, from the start to the end of the cleaning process, is set to be longer than the residence time, from the time the raw water flows into the water softening chamber 3209 to the time the raw water flows out of the neutralization chamber 3210. This allows the water containing a large number of desorbed hardness ions present in the water softening chamber 3209 to be discharged, and the water in the water softening chamber 3209 to be replaced with raw water.

[0607] During the regeneration process, solid calcium carbonate adheres to the surface of the second electrode 3202. If the amount of calcium carbonate deposited on the electrode surface increases, problems such as higher voltage when energized and difficulty in removing calcium carbonate from the electrode surface arise. Therefore, it is necessary to periodically perform an electrode cleaning process to remove calcium carbonate from the cathode surface.

[0608] During the electrode cleaning process, the first electrode 3201 is connected to the negative electrode, and the second electrode 3202 is connected to the positive electrode, meaning the polarity of the electrodes is reversed relative to the regeneration process. This operation generates H2O from the second electrode 3202. + Calcium carbonate on the surface of the second electrode 3202 reacts with H + Dissolves through reaction. Electrode cleaning is performed during or after the regeneration process.

[0609] As described above, in the water softening device 3100, the softening of raw water by the water softening process and the maintenance of the water softening device 3100 by the regeneration process, the cleaning process and the electrode cleaning process are repeatedly performed.

[0610] (Effects, etc.)

[0611] The water softening device 3100 according to this embodiment can enjoy the following effects.

[0612] (1) The water softening device 3100 comprises: a water softening chamber 3209 having a weakly acidic cation exchange resin 3213 for generating soft water from raw water containing hardness components; a neutralization chamber 3210 having a weakly basic anion exchange resin 3214 for neutralizing the soft water; an inner peripheral diaphragm 3215 for separating the water softening chamber 3209 and the neutralization chamber 3210 in a manner that allows soft water to pass through; a water guiding section 3203 for introducing raw water from the outside into the water softening chamber 3209; and a water delivery section 3204. The water softening chamber 3209 is equipped with a first electrode 3201, which is surrounded by a weakly acidic cation exchange resin 3213 and functions as an anode during the regeneration of the weakly acidic cation exchange resin 3213. A second electrode 3202 is also provided within the neutralization chamber 3210, surrounded by a weakly basic anion exchange resin 3214 and functions as a cathode during the regeneration of the weakly basic anion exchange resin 3214. The water softening chamber 3209, the inner circumferential diaphragm 3215, the neutralization chamber 3210, and the water delivery section 3204 are arranged sequentially from the water guide section 3203, which has a central axis I perpendicular to the bottom surface of the water softening chamber 3209, towards the outer periphery of a circle centered on the central axis I. The first electrode 3201 is positioned within the water softening chamber 3209, offset from the water guide section 3203.

[0613] More specifically, the first electrode 3201 is disposed on the same radius of a circle in a cross section parallel to the bottom surface of the water softening chamber 3209, at a position closer to the water guide portion 3203 than the midpoint between the first boundary portion 3401 and the inner peripheral diaphragm 3215, wherein the first boundary portion 3401 is the boundary between the water guide portion 3203 and the water softening chamber 3209.

[0614] With this structure, hydrogen ions can be generated near the weakly acidic cation exchange resin 3213, which has a high adsorption capacity for hardness ions, within the water softening chamber 3209 during the regeneration process. Therefore, the loss of the generated hydrogen ions due to reaction with other ions before regeneration of the weakly acidic cation exchange resin 3213 can be suppressed, thereby improving regeneration efficiency.

[0615] (2) In the water softening device 3100, the second electrode 3202 is disposed in the neutralization chamber 3210 at a position biased toward the inner peripheral diaphragm 3215.

[0616] More specifically, the second electrode 3202 is disposed on the same radius at a position closer to the inner circumferential diaphragm 3215 than the midpoint between the inner circumferential diaphragm 3215 and the second boundary portion 3402, wherein the second boundary portion 3402 is the boundary between the neutralization chamber 3210 and the water supply portion 3204.

[0617] With this structure, during the regeneration process, hydroxide ions can be generated near the weakly basic anion exchange resin 3214, which has a high ion adsorption capacity, within the neutralization chamber 3210. Therefore, the loss of the generated hydroxide ions due to reaction with other ions before regeneration of the weakly basic anion exchange resin 3214 can be suppressed, thereby improving regeneration efficiency.

[0618] (3) In the water softening device 3100, a pair of first electrodes 3201 and second electrodes 3202 are arranged on the same radius in a cross section parallel to the bottom surface of the water softening chamber 3209, and are positioned such that the ratio of the distance from the water guide portion 3203 to the first electrode 3201 to the first distance from the first boundary portion 3401 to the inner peripheral diaphragm 3215 is equal to the ratio of the distance from the inner peripheral diaphragm 3215 to the second electrode 3202 to the second distance from the inner peripheral diaphragm 3215 to the second boundary portion 3402.

[0619] With this structure, the first electrode 3201 and the second electrode 3202 are located in the same position relative to the center side in each chamber.

[0620] The present disclosure has been described above based on embodiments. These embodiments are illustrative, and those skilled in the art will understand that various modifications can exist in the combination of these constituent elements or processes, and such modifications are also within the scope of the present disclosure.

[0621] (Modified Example)

[0622] In Embodiment 9, the case where the first electrode 3201 is more biased toward the center of the circle than the midpoint between the first boundary portion 3401 and the inner peripheral diaphragm 3215, and the second electrode 3202 is more biased toward the center of the circle than the midpoint between the inner peripheral diaphragm 3215 and the second boundary portion 3402, has been described. However, this disclosure is not limited to this. For example, only the first electrode 3201 may be more biased toward the center than the midpoint between the first boundary portion 3401 and the inner peripheral diaphragm 3215. The water softening device disclosed herein can reduce the frequency of drainage or eliminate the need for drainage itself, thus reducing the amount of drainage. As a side effect, it can also shorten the regeneration time and increase the electrode life, making it useful as a water softening device, etc.

[0623] Industrial availability

[0624] The water softening device disclosed herein can reduce the frequency of drainage or eliminate the need for drainage itself, thereby reducing the amount of drainage. As a side effect, it can also shorten the regeneration time and increase the electrode life, thus making it useful as a water softening device, etc.

[0625] Explanation of reference numerals in the attached figures

[0626] 100: Water softening device; 101: Weakly acidic cation exchange resin; 102: Weakly basic anion exchange resin; 103, 103a, 103b: First electrode; 104, 104a, 104b: Second electrode; 105: Inner peripheral diaphragm; 106: Outer peripheral diaphragm; 107: Water guide section; 108: Water supply section; 108a: Side space; 108b: Upper space; 109: Exhaust valve; 110: Water supply section outlet; 111: Water guide section inlet; 112: Cover; 113: Boundary line; 201: Water softening chamber; 202: Neutralization chamber; 203: Outer shell; 204: First space; 205: Second space; I: Central axis; S, T, V, W: Distance; 1100, 1100b, 1 100c, 1100d, 1100e, 1100f: Water softening device; 1101: Raw water conductivity measuring unit; 1102: Soft water conductivity measuring unit; 1103: Water volume measuring unit; 1104, 1104a, 1104b: Raw water supply pipe; 1105, 1105a: Soft water supply pipe; 1106: Soft water supply pipe on / off valve; 1107, 1107a: Drainage piping; 1108: Drainage pipe on / off valve; 1109: Outer casing; 1110: Control unit; 1111: Adsorption capacity estimation unit; 1112: Storage unit; 1113: Timing unit; 1201, 1201a, 1201b: First electrode; 1202, 1202a, 1202b: Second electrode; 1203: Water guiding unit. 1204: Water supply section; 1204a: Side space; 1204b: Upper space; 1205: Air vent valve; 1206: Water supply section outlet; 1207: Water guide section inlet; 1208: Cover; 1209: Water softening chamber; 1210: Neutralization chamber; 1211: First space; 1212: Second space; 1213: Weakly acidic cation exchange resin; 1214: Weakly basic anion exchange resin; 1215: Inner circumferential diaphragm; 1216: Outer circumferential diaphragm; 1301: Reagent addition piping; 1302: Reagent slow release section; 1303: Reagent addition piping on / off valve; 1304: Raw water supply pipe on / off valve; 1401: Storage chamber; 1402: Inlet; 1403: First water inlet; 1404 1405: Second water inlet; 1406: Reclaimed water return piping; 1501, 1501a, 1501b: Water softening module; 1502: Connecting pipe; 1503a, 1503b, 1503c: Conductivity meter; 1601: Upstream drain pipe; 1602: Discharge valve; 1603: Drainage flow measurement unit; 2100: Water softening device; 2101: Raw water conductivity measurement unit; 2102: Soft water conductivity measurement unit; 2103: Flow measurement unit; 2104: Raw water supply pipe; 2105: Soft water supply pipe; 2106: Soft water supply pipe on / off valve; 2107: Drainage piping; 2108: Drainage pipe on / off valve; 2109: Outer casing; 2110: Control unit;2111: Adsorption capacity estimation unit; 2112: Storage unit; 2113: Timing unit; 2114: Bypass piping; 2115: Bypass piping on / off valve; 2201, 2201a, 2201b: First electrode; 2202, 2202a, 2202b: Second electrode; 2203: Water guiding section; 2204: Water supply section; 2204a: Side space; 2204b: Upper space; 2205: Vent valve; 2206: Water supply section outlet; 2207: Water guiding section inlet; 22 08: Cover; 2209: Water softening chamber; 2210: Neutralization chamber; 2211: First space; 2212: Second space; 2213: Weakly acidic cation exchange resin; 2214: Weakly basic anion exchange resin; 2215: Inner circumferential diaphragm; 2216: Outer circumferential diaphragm; 3100: Water softening device; 3101: Raw water conductivity measuring unit; 3102: Soft water conductivity measuring unit; 3103: Water volume measuring unit; 3104: Raw water supply pipe; 3105: Soft water supply pipe 3106: Soft water supply pipe on / off valve; 3107: Drainage piping; 3108: Drainage pipe on / off valve; 3109: Outer casing; 3110: Control unit; 3111: Adsorption capacity estimation unit; 3112: Storage unit; 3113: Timing unit; 3201, 3201a, 3201b: First electrode; 3202, 3202a, 3202b: Second electrode; 3203: Water guiding unit; 3204: Water delivery unit; 3204a: Side space; 3204b: Upper space; 32 05: Air vent valve; 3206: Water supply outlet; 3207: Water guide inlet; 3208: Cover; 3209: Water softening chamber; 3210: Neutralization chamber; 3211: First space; 3212: Second space; 3213: Weakly acidic cation exchange resin; 3214: Weakly basic anion exchange resin; 3215: Inner circumferential diaphragm; 3216: Outer circumferential diaphragm; 3401: First boundary section; 3402: Second boundary section; 3403: Middle section; 3404: Middle section.

Claims

1. A water softening device, comprising: The water softening chamber contains a weakly acidic cation exchange resin to produce soft water from raw water containing hardness components. The neutralization chamber contains a weakly basic anion exchange resin for neutralizing the soft water. A diaphragm that separates the water softening chamber from the neutralization chamber in a manner that allows the soft water to pass through; The first electrode functions as the anode during the regeneration of the weakly acidic cation exchange resin. as well as The second electrode functions as a cathode during the regeneration of the weakly basic anion exchange resin. The first electrode is disposed in the water softening chamber such that it is surrounded by the weakly acidic cation exchange resin. The second electrode is disposed in the neutralization chamber in such a manner that it is surrounded by the weakly basic anion exchange resin.

2. The water softening device according to claim 1, wherein, The first electrode is positioned in contact with the weakly acidic cation exchange resin. The second electrode is positioned in contact with the weakly basic anion exchange resin.

3. The water softening device according to claim 1, wherein, The first electrode is configured such that a space is formed above the upper end of the first electrode by positioning its upper end below the water surface in the water softening chamber when the weakly acidic cation exchange resin begins regeneration. The distance from the bottom surface of the water softening chamber to the lower end of the first electrode is shorter than the distance from the water surface to the upper end of the first electrode. The weakly acidic cation exchange resin is filled in the water softening chamber around the first electrode and in the space above it.

4. The water softening device according to claim 1, wherein, The second electrode is configured such that a space is formed above the upper end of the second electrode by positioning its upper end below the water surface in the neutralization chamber when the weakly basic anion exchange resin begins regeneration. The distance from the bottom surface of the neutralization chamber to the lower end of the second electrode is shorter than the distance from the water surface to the upper end of the second electrode. The weakly basic anion exchange resin is filled in the neutralization chamber around the second electrode and in the space above it.

5. The water softening device according to claim 1, wherein, It also has a cylindrical outer shell containing the water softening chamber and the neutralization chamber inside. The neutralization chamber is located on the outer periphery of the water softening chamber relative to the central axis of the cylinder of the outer shell, and surrounds the water softening chamber.

6. The water softening device according to claim 5, wherein, It also includes a water guide section for introducing the raw water into the water softening chamber. The water guiding section extends from the lower part to the upper part of the water softening chamber, and delivers the raw water from the side of the water guiding section in the direction of the outer periphery relative to the central axis of the cylinder.

7. The water softening device according to claim 5, wherein, It also includes a water delivery unit, which is disposed on the outer periphery of the neutralization chamber relative to the central axis of the cylinder and surrounds the neutralization chamber. The water delivery unit delivers water from the neutralization chamber to the outside of the device from a position above the upper part of the neutralization chamber in the direction of the outer periphery relative to the central axis.

8. The water softening device according to claim 5, wherein, When viewed from above, a pair of first and second electrodes are positioned on the same radius.

9. The water softening device according to claim 1, wherein, The amount of the weakly basic anion exchange resin is greater than or equal to the amount of the weakly acidic cation exchange resin.

10. The water softening device according to claim 1, wherein, The membrane is a water-permeable membrane with a pore size smaller than that of the weakly acidic cation exchange resin and the weakly basic anion exchange resin.

11. The water softening device according to claim 1, wherein, It also includes a control unit that controls the regeneration of the weakly acidic cation exchange resin and the weakly basic anion exchange resin. The control unit performs the following process: The water softening process involves the water to be treated flowing in from the bottom of the water softening chamber and then sequentially through the water softening chamber and the neutralization chamber, thereby obtaining soft water. In the regeneration process, electricity is applied to the first electrode and the second electrode, and hydrogen ions are generated from the first electrode and hydroxide ions are generated from the second electrode through water electrolysis. The generated hydrogen ions are used to regenerate the weakly acidic cation exchange resin, and the generated hydroxide ions are used to regenerate the weakly basic anion exchange resin. During the cleaning process, cations released from the weakly acidic cation exchange resin through the regeneration process are discharged from the water softening chamber, and anions released from the weakly basic anion exchange resin are discharged from the neutralization chamber. as well as During or after the regeneration process, the first electrode is connected to the negative electrode and the second electrode is connected to the positive electrode, so that the solids adhering to the surface of the second electrode during the regeneration process are dissolved.

12. The water softening device according to claim 11, wherein, It also has: A water volume measuring unit measures the volume of the raw water that is introduced into the water softening chamber; The raw water conductivity measuring unit measures the conductivity of the raw water before it comes into contact with the cation exchange resin. The soft water conductivity measuring unit measures the conductivity of neutralized soft water after it has come into contact with the anion exchange resin. as well as The adsorption capacity estimation unit estimates the amount of ions adsorbed in the water softening chamber for a specific ion. The adsorption amount estimation unit estimates the amount of ions adsorbed in the water softening chamber during the water softening process based on the water volume measured by the water volume measuring unit, the conductivity of the raw water measured by the raw water conductivity measuring unit, and the conductivity of the neutralized soft water measured by the soft water conductivity measuring unit.

13. The water softening device according to claim 12, wherein, The control unit sets the execution time of the regeneration process based on the amount of ions adsorbed as estimated by the adsorption amount estimation unit.

14. The water softening device according to claim 11, wherein, It also includes an electrolyte input unit, which, during the regeneration process, inputs electrolytes other than hydrogen ions and hydroxide ions into the water softening chamber and the neutralization chamber.

15. The water softening device according to claim 14, wherein, Before the regeneration process is energized, the electrolyte input unit allows the raw water containing the hardness component to flow into the water softening chamber and the neutralization chamber.

16. The water softening device according to claim 14, wherein, The electrolyte input section adds a reagent containing the electrolyte to the raw water.

17. The water softening apparatus according to claim 14, wherein, Before the regeneration process is energized, the electrolyte input unit introduces wastewater containing at least one of the cations and anions discharged during the cleaning process prior to the regeneration process into the water softening chamber and the neutralization chamber.

18. The water softening apparatus according to claim 17, wherein, It also has a storage room for storing the wastewater. The storage room is equipped with: case; An inlet is provided at the upper part of the housing for allowing the drainage to flow into the housing; The first water inlet is located on the upper part of the housing and is used to discharge the drain water to the outside of the housing; as well as The second water inlet, located at the lower part of the housing, is used to deliver the drained water to the water softening chamber. The electrolyte input unit will input the drainage from the second water inlet into the water softening chamber.

19. The water softening apparatus according to claim 11, wherein, The control unit includes an adsorption amount estimation unit that determines the amount of ions adsorbed in the water softening chamber. During the regeneration process, the control unit controls the current value applied to the first electrode and the second electrode based on the amount of ions adsorbed as estimated by the adsorption amount estimation unit.

20. The water softening apparatus according to claim 19, wherein, It also includes a timing unit that measures the elapsed time from the start of the regeneration process. The control unit changes the current value applied to the first electrode and the second electrode based on the elapsed time measured by the timing unit.

21. The water softening apparatus according to claim 20, wherein, If the elapsed time exceeds a specific first reference value, the control unit increases the current value applied to the first electrode and the second electrode.

22. The water softening device according to claim 19, wherein, It also has a voltage measuring unit that measures the voltage when a current is applied. The control unit changes the current value applied to the first electrode and the second electrode based on the change in voltage measured by the voltage measurement unit.

23. The water softening device according to claim 11, wherein, It has multiple water softening modules, each of which includes a water softening chamber, a neutralization chamber, and a diaphragm. It also includes an adsorption capacity estimation unit, which determines the amount of ions adsorbed in the water softening chamber by each of the multiple water softening modules. During the regeneration process The control unit changes at least one of the current value and the energizing time for each of the plurality of water softening modules based on the ion adsorption amount estimated by the adsorption amount estimation unit.

24. The water softening device according to claim 11, wherein, The control unit performs a drainage process during the regeneration process, in which the acidic electrolyzed water in the water softening chamber and the alkaline electrolyzed water in the neutralization chamber are discharged outside the device.

25. The water softening apparatus according to claim 24, wherein, The time from the start to the end of the drainage process, i.e., the drainage time, is longer than the time from the time the raw water flows into the water softening chamber to the time the raw water flows out of the neutralization chamber, i.e., the retention time.

26. The water softening apparatus according to claim 24, wherein, It also includes a water volume measuring unit, which measures the volume of the soft water flowing out of the neutralization chamber. During the drainage process, if the water volume measured by the water volume measuring unit from the start of the drainage process is less than the volume of the water softening chamber and the neutralization chamber, the control unit continues to execute the drainage process. If the water volume measured by the water volume measuring unit from the start of the drainage process is greater than or equal to the volume of the water softening chamber and the neutralization chamber, the control unit terminates the drainage process.

27. The water softening apparatus according to claim 11, wherein, The time from the start to the end of the cleaning process, i.e., the cleaning time, is longer than the time from the time the raw water flows into the water softening chamber to the time the raw water flows out of the neutralization chamber, i.e., the retention time.

28. The water softening apparatus according to claim 11, wherein, It also includes a water volume measuring unit, which measures the volume of the soft water flowing out of the neutralization chamber. During the cleaning process, if the water volume measured by the water volume measuring unit from the start of the cleaning process becomes greater than the volume of the water softening chamber and the neutralization chamber, the control unit terminates the cleaning process.

29. The water softening apparatus according to claim 11, wherein, It also has: A raw water conductivity measuring unit determines the conductivity of the raw water; and The drainage conductivity measuring unit determines the conductivity of the drainage flowing out of the neutralization chamber during the cleaning process. The control unit terminates the cleaning process when the conductivity of the drain water, as determined by the drain conductivity measuring unit, becomes equal to the conductivity of the raw water, as determined by the raw water conductivity measuring unit.

30. The water softening apparatus according to claim 11, wherein, The control unit also performs an electrode cleaning process during or after the regeneration process. During the electrode cleaning process, the first electrode is connected to the negative electrode and the second electrode is connected to the positive electrode, so that the solids adhering to the surface of the second electrode during the regeneration process are dissolved.

31. The water softening device according to claim 1, wherein, It also has: A water guide section, located on the inner periphery of the water softening chamber, supplies the raw water to the water softening chamber; A water delivery unit, which supplies the neutralized soft water generated in the neutralization chamber to the outside; and The control unit controls the regeneration of the weakly acidic cation exchange resin. The neutralization chamber is located on the outer periphery of the water softening chamber. The control unit performs the following process: The water softening process involves the raw water flowing in from the water guide section and sequentially passing through the water softening chamber and the neutralization chamber to obtain the neutralized soft water. The regeneration process involves water electrolysis after the water softening process has been performed for a specified period, and the generated hydrogen ions are used to regenerate the weakly acidic cation exchange resin. as well as During the drainage process, cations released from the weakly acidic cation exchange resin through the regeneration process are discharged from the water softening chamber, and anions released from the weakly basic anion exchange resin are discharged from the neutralization chamber. During the drainage process, water containing the cations is discharged from the water guide section.

32. The water softening device according to claim 31, wherein, The drainage volume during the drainage process is smaller than the sum of the volumes of the water guiding section, the water softening chamber, and the neutralization chamber.

33. The water softening device according to claim 31, wherein, The weakly acidic cation exchange resin is filled in the water softening chamber. The weakly basic anion exchange resin is filled in the neutralization chamber. The drainage volume during the drainage process is smaller than the sum of the volume excluding the portion occupied by the weakly acidic cation exchange resin in the water softening chamber and the volume excluding the portion occupied by the weakly basic anion exchange resin in the neutralization chamber.

34. The water softening device according to claim 31, wherein, The weakly acidic cation exchange resin is filled in the water softening chamber. The volume of water discharged during the drainage process is greater than the volume outside the area occupied by the weakly acidic cation exchange resin in the water softening chamber.

35. The water softening device according to claim 31, wherein, The control unit performs the drainage process multiple times during the regeneration process.

36. The water softening apparatus according to claim 35, wherein, During the regeneration process, the control unit applies a voltage between the first electrode and the second electrode, and determines the execution of the drainage process based on the applied voltage.

37. The water softening device according to claim 31, wherein, The raw water supplied during the drainage process flows in from the water delivery section.

38. The water softening device according to claim 1, wherein, It also has: A water guiding section, which guides the raw water from the outside into the water softening chamber; and The water delivery unit transports the neutralized soft water generated in the neutralization chamber to the outside. The water softening chamber, the diaphragm, the neutralization chamber, and the water delivery section are arranged sequentially from the water guide section having a central axis perpendicular to the bottom surface of the water softening chamber, toward the outer periphery of a circle centered on the central axis. The first electrode is positioned in the water softening chamber at a location biased towards the water guide section.

39. The water softening device according to claim 38, wherein, The second electrode is positioned in the neutralization chamber at a location biased toward the diaphragm side.

40. The water softening apparatus according to claim 38, wherein, The first electrode is positioned on the water guide side closer to the midpoint between the first boundary portion and the diaphragm, on the same radius of the circle in a cross section parallel to the bottom surface of the water softening chamber. The first boundary portion is the boundary between the water guide portion and the water softening chamber.

41. The water softening apparatus according to claim 40, wherein, The second electrode is positioned on the same radius closer to the diaphragm side than the midpoint between the diaphragm and the second boundary portion, which is the boundary between the neutralization chamber and the water supply portion.

42. The water softening device according to claim 41, wherein, A pair of first and second electrodes are disposed on the same radius in the cross section. A pair of first electrodes and second electrodes are positioned such that the ratio of the distance from the water guide portion to the first electrode to the first distance from the first boundary portion to the diaphragm is equal to the ratio of the distance from the diaphragm to the second electrode to the second distance from the diaphragm to the second boundary portion.

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