Water softening unit

Abstract

To provide a water softening device that can reduce the amount of wastewater discharged during regeneration and enable efficient resin regeneration. [Solution] The water softening device comprises a water softening chamber 209 that generates softened water, a neutralization chamber 210 that neutralizes the softened water, an inner circumferential diaphragm 215 between the water softening chamber 209 and the neutralization chamber 210, a water intake section 203 that introduces raw water into the water softening chamber 209, a water supply section 204 that sends the neutralized softened water to the outside, a first electrode 201 provided in the water softening chamber 209, and a second electrode 202 provided in the neutralization chamber 210. Furthermore, the water supply section 204 is arranged in the following order from the water supply section 203, which has a central axis perpendicular to the bottom surface of the water softening chamber 209, toward the outer circumference of a circle centered on the central axis: the water softening chamber 209, the inner circumferential diaphragm 215, the neutralization chamber 210, and the water supply section 204. The first electrode 201 is provided with a first distance 405 between it and the inner circumferential diaphragm 215, and the second electrode 202 is provided with a second distance 406 between it and the inner circumferential diaphragm 215, with the first distance 405 being less than or equal to the second distance 406.

Description

[Technical Field]

[0001] This invention relates to a water softening device that utilizes ion exchange resin. [Background technology]

[0002] Currently, water softeners are widely used, mainly in hard water areas, to remove hardness components from tap water. However, these water softeners require periodic salt replenishment.

[0003] Furthermore, in order to address the challenges of the workload associated with salt replenishment and the performance issue of not being able to obtain soft water if salt replenishment is not carried out properly, a soft water technology has been developed that allows maintenance to be performed without using salt (for example, Patent Document 1).

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

[0005] In conventional technology, once a certain amount of hardness ions adsorb to the resin, the resin needs to be regenerated. For example, in the regeneration process described in Patent Document 1, electrodes are used to apply a voltage to the BP film and resin chamber located between the electrodes. An interface between cation exchange resin and anion exchange resin exists in the BP film or ion exchange resin chamber. When a voltage is applied to this interface, water molecules cleave and H + and OH - It generates. The generated H + This produces a weakly acidic cation exchange resin, and the generated OH - This allows for the regeneration of weakly basic anion exchange resins. [Prior art documents] [Patent Documents]

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

[0007] However, in the technology described in Patent Document 1, hardness ions that have been detached from the ion exchange resin tend to be re-adsorbed onto the ion exchange resin, which can easily inhibit the reaction during resin regeneration. Therefore, it is necessary to perform regeneration while passing water through the resin to discharge the detached hardness ions. This water flow operation has the problem of increasing the amount of wastewater discharged during resin regeneration.

[0008] This invention has been made in view of the problems of the prior art. The object of this invention is to provide a water softening device that can suppress wastewater during regeneration and efficiently regenerate resin. [Means for solving the problem]

[0009] To solve the above problems, the water softening apparatus according to the present invention comprises: a water softening chamber having a weakly acidic cation exchange resin that generates softened water from raw water containing hardness components; a neutralization chamber having a weakly basic anion exchange resin that neutralizes the softened water; a diaphragm that partitions the water softening chamber and the neutralization chamber so that softened water can flow between them; a water intake section that introduces raw water from the outside into the water softening chamber; a water supply section that sends the neutralized softened water generated in the neutralization chamber to the outside; a first electrode provided in the water softening chamber surrounded by the weakly acidic cation exchange resin and acting as an anode when the weakly acidic cation exchange resin is regenerated; and a second electrode provided in the neutralization chamber surrounded by the weakly basic anion exchange resin and acting as a cathode when the weakly basic anion exchange resin is regenerated. The water intake section has a central axis perpendicular to the bottom surface of the water softening chamber. The softening chamber, diaphragm, neutralization chamber, and water supply section are arranged in the order of the outer circumference of a circle centered on the central axis. The first electrode is provided with a first distance from the diaphragm, and the second electrode is provided with a second distance from the diaphragm. The first distance is less than or equal to the second distance. This achieves the intended purpose. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a water softening device capable of suppressing drainage during regeneration and efficiently regenerating resin.

Brief Description of the Drawings

[0011] [Figure 1] Schematic diagram of the water softening device in Embodiment 1 [Figure 2] Perspective view of the water softening device in Embodiment 1 [Figure 3] Cross-sectional view of the water softening device in Embodiment 1 [Figure 4] Cross-sectional view showing the A-A' cross-section of the water softening device in Embodiment 1 [Figure 5] Diagram including an equation showing the principle of the water softening device in Embodiment 1 [Figure 6] Diagram showing the time change of the hydrogen ion consumption rate by the weakly acidic cation exchange resin during the regeneration process [Figure 7] Schematic diagram showing the ion distribution during the regeneration process

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are an example of embodying the present invention and do not limit the technical scope of the present invention. Also, each drawing described in the embodiments is a schematic drawing, and the sizes and thicknesses of the components in each drawing and the ratios thereof do not necessarily reflect the actual dimensional ratios.

[0013] (Embodiment 1) Referring to FIGS. 1, 2, and 3, the water softening device 100 according to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic diagram showing the configuration of the water softening device 100 according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the configuration of the water softening device 100 according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view showing the configuration of the water softening device 100 according to Embodiment 1 of the present invention. In FIGS. 1 to 3, each element of the water softening device 100 is conceptually shown. Also, in FIG. 2, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are omitted from the description.

[0014] The water softening device 100 is a device that generates neutral soft water from raw water containing hardness components supplied from the outside. The raw water is the water (water to be treated) introduced into the water softening device 100 from the raw water supply pipe 104 described later, and is, for example, well water or tap water. The raw water contains hardness components (calcium ions, magnesium ions). By performing a water softening process for softening the raw water using the water softening device 100, neutral soft water with reduced hardness can be obtained from the raw water with high hardness, and soft water can be used even in an area where the hardness of the raw water is high. In addition, after the water softening device 100 performs the water softening process for a certain period of time, a regeneration process for regenerating the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 described later is performed. Details of the water softening process and the regeneration process will be described later.

[0015] As shown in FIG. 1, the water softening device 100 includes a raw water supply pipe 104, a drain pipe 115, a casing 109, a soft water supply pipe 105, a drain pipe 107, and a control unit 110.

[0016] The raw water supply pipe 104 is a pipe that connects a water source of raw water such as a water supply and an inlet 207 of a water guiding section described later, and a raw water conductivity measuring section 101 is provided on its flow path.

[0017] The raw water conductivity measuring section 101 calculates the total ion concentration of the raw water flowing into the raw water supply pipe 104. The calculated total ion concentration information of the raw water is transmitted to the control unit 110.

[0018] The drain pipe 115 is a pipe that branches off from the raw water supply pipe 104. The drain pipe 115 is a pipe for draining water from the casing 109. More specifically, the drain pipe 115 is a pipe for draining water from the casing 109 during the regeneration process. The drain pipe 115 is equipped with a drain valve 114.

[0019] The drain valve 114 switches the drain pipe 115 between a state where water can pass through and a state where water cannot pass through. More specifically, the drain valve 114, for example, in the water softening process, makes the drain pipe 115 a state where water cannot pass through, and in the regeneration process, switches the drain pipe 115 back to a state where water can pass through, i.e., a state where water can be drained. The drain valve 114 is composed of, for example, a known three-way valve.

[0020] The casing 109 is a hollow cylindrical component, and the raw water is softened and the ion exchange resin is regenerated within the casing 109.

[0021] As shown in Figures 2 and 3, the hollow space of the casing 109 is provided with a water guide section 203, a water softening chamber 209, a neutralization chamber 210, and a water supply section 204, arranged in order from the side closest to the central axis I connecting the top and bottom surfaces of the casing 109 toward the outer periphery. The water guide section inlet 207 is located at the center of the bottom surface of the casing 109, i.e., on the central axis I. The water supply section outlet 206 is located at the center of the top surface of the casing 109, i.e., on the central axis I. The central axis I of the casing 109 coincides with the central axes of the water guide section 203, water softening chamber 209, neutralization chamber 210, and water supply section 204. The central axis I is perpendicular to the bottom surface of the water softening chamber 209.

[0022] The water intake inlet 207 is located at the bottom of the casing 109 and supplies raw water to the water intake section 203. The central axis of the water intake inlet 207 coincides with the central axis I of the casing 109. The water intake inlet 207 is connected in communication with the raw water supply pipe 104.

[0023] The water conduit 203 is a cylindrical member and is connected at its lower end to the water conduit inlet 207. The water conduit 203 guides raw water into the water softening device 100 and supplies it to the water softening chamber 209. A pipe or other tube with an internal space can be used as the water conduit 203.

[0024] The water guide section 203 is configured to allow raw water introduced into the water softening device 100 to flow uniformly to the water softening chamber 209 and the neutralization chamber 210. Specifically, the water guide section 203 is located in the center of the casing 109, and its outer circumference is in contact with the water softening chamber 209. In other words, the water guide section 203 is located on the central axis I. Furthermore, the water guide section 203 extends from the lower to the upper part of the water softening chamber 209 and the neutralization chamber 210, more precisely from the lower end to the upper end, and the length of the portion that can supply raw water to the water softening chamber 209 and the neutralization chamber 210 is equal to the height of the water softening chamber 209 and the neutralization chamber 210. The water guide section 203 has multiple holes on its side surface, and raw water is sent from these holes in the direction from the central axis I of the casing 109 outward, that is, to the water softening chamber 209. Furthermore, it is preferable that the multiple holes are uniformly arranged in the circumferential direction on the side surface of the water guide section 203. With such a configuration, the raw water introduced into the device can be uniformly flowed to the water softening chamber 209 and the neutralization chamber 210. As a result, the raw water is evenly supplied to the weakly acidic cation exchange resin 213 particles filling the water softening chamber 209 and the weakly basic anion exchange resin 214 particles filling the neutralization chamber 210, allowing for efficient utilization of the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 as a whole.

[0025] The multiple pores on the side surface of the water guide section 203 are smaller than the particle size of the weakly acidic cation exchange resin particles, and since the lower limit of the particle size of the weakly acidic cation exchange resin is around 0.3 mm, the diameter of the pores provided on the surface of the water guide section 203 is smaller than that. This prevents the outflow of ion exchange resin from the water softening chamber 209 without hindering water permeability.

[0026] The water softening chamber 209 is a cylindrical space (first space 211) located within the casing 109, on the outer circumference side of the water guide section 203 with respect to the central axis I of the casing 109, and contains a weakly acidic cation exchange resin 213. The central axis of the water softening chamber 209 coincides with the central axis I of the casing 109. The water softening chamber 209 is in contact with the water guide section 203 on its inner cylindrical surface, in contact with the inner circumferential diaphragm 215, which is a permeable cylindrical membrane, on its outer surface, and in contact with the lid section 208 on its upper surface. The water softening chamber 209 is filled with the weakly acidic cation exchange resin 213 and is provided with a first electrode 201.

[0027] The weakly acidic cation exchange resin 213 is an ion exchange resin having a carboxyl group, and for example, those having a methacrylic acid skeleton or an acrylic acid skeleton can be used. In this embodiment, a resin having an acrylic acid skeleton is used as the weakly acidic cation exchange resin 213.

[0028] The first electrode 201 is not energized during the water softening process and acts as an anode in the regeneration process of the weakly acidic cation exchange resin 213. The first electrode 201 is surrounded by the weakly acidic cation exchange resin 213 within the water softening chamber 209. Here, "surrounded" means that the surface of the first electrode 201 is in contact with the surface of the weakly acidic cation exchange resin 213 from top to bottom over its entire circumference. However, the weakly acidic cation exchange resin 213 is usually spherical, and it is necessary to ensure a water passage for raw water. Therefore, the weakly acidic cation exchange resin 213 is not in complete contact with the surface of the first electrode 201; a state in which it is partially in contact with the surface over its entire circumference also falls under the category of "the first electrode 201 being surrounded by the weakly acidic cation exchange resin 213."

[0029] The upper end of the first electrode 201 is positioned below the water level in the water softening chamber 209 at the start of the regeneration process. Multiple first electrodes 201 are provided, and they are arranged in the water softening chamber 209 such that the distance between adjacent first electrodes 201 is equal. The material of the first electrode 201 can be a precious metal or an alloy of a precious metal. This is because the presence of a precious metal acts as a catalyst for water electrolysis and does not dissolve even under acidic conditions. Examples of precious metal materials include platinum, iridium, and ruthenium. Examples of electrode forms include a single precious metal wire electrode, an electrode with a precious metal wire wrapped around a support, and a mesh-like precious metal electrode. It is also possible to use a metal rod other than a precious metal, such as titanium (Ti), as a support, with a precious metal coated on its surface. However, since the presence of dissimilar metal interfaces makes degradation originating from the interface more likely, it is preferable to use a pure precious metal or a precious metal alloy.

[0030] The inner circumferential diaphragm 215 is a permeable membrane that partitions the water softening chamber 209 and the neutralization chamber 210, allowing softened water to pass through. The inner surface of the inner circumferential diaphragm 215 covers the outer surface of the water softening chamber 209 and is in contact with it. The outer surface of the inner circumferential diaphragm 215 also covers the inner surface of the neutralization chamber 210 and is in contact with it. As a result, the inner circumferential diaphragm 215 partitions the water softening chamber 209 and the neutralization chamber 210, allowing the acidic softened water generated in the water softening chamber 209 to pass through. Note that "covering" means being located around the object, and it is not necessary to completely enclose the object. The inner circumferential diaphragm 215 corresponds to the "diaphragm" in the scope of the claims.

[0031] The neutralizing chamber 210 is soft within the casing 109 relative to the central axis I of the casing 109. The neutralization chamber 210 is a cylindrical space (second space 212) located on the outer periphery of the hydrate chamber 209, containing a weakly basic anion exchange resin 214. The central axis of the neutralization chamber 210 coincides with the central axis I of the casing 109. The neutralization chamber 210 is in contact with the outer surface of the inner circumferential diaphragm 215 on its cylindrical inner side, in contact with the inner surface of the outer circumferential diaphragm 216, which is a permeable cylindrical membrane, on its cylindrical outer side, and in contact with the lid 208 on its top surface. The neutralization chamber 210 is filled with the weakly basic anion exchange resin 214 and is equipped with a second electrode 202.

[0032] The weakly basic anion exchange resin 214 is an ion exchange resin having a tertiary amine or a quaternary amine as a functional group, and in this embodiment, a resin with a higher proportion of tertiary amine than quaternary amine is used.

[0033] The second electrode 202 is not energized during the water softening process and acts as a cathode in the regeneration process of the weakly basic anion exchange resin 214. The second electrode 202 is surrounded by the weakly basic anion exchange resin 214 within the neutralization chamber 210. Here, "surrounded" means that the surface of the second electrode 202 is in contact with the surface of the weakly basic anion exchange resin 214 from top to bottom over its entire circumference. However, the weakly basic anion exchange resin 214, like the weakly acidic cation exchange resin 213, is usually spherical, and it is necessary to secure a passage for the raw water (strictly speaking, acidic softened water). Therefore, the weakly basic anion exchange resin 214 is not in complete contact with the surface of the second electrode 202; a state in which it is partially in contact with the surface over its entire circumference also falls under the category of "the second electrode 202 being surrounded by the weakly basic anion exchange resin 214."

[0034] The upper end of the second electrode 202 is positioned below the water level in the neutralization chamber 210 at the start of the regeneration process. Multiple second electrodes 202 are provided, and they are arranged in the neutralization chamber 210 such that the distance between adjacent second electrodes 202 is equal. The material of the second electrode 202 can be a precious metal or an alloy of a precious metal. This is because the presence of a precious metal acts as a catalyst for water electrolysis and does not dissolve even under acidic conditions. Examples of precious metal materials include platinum, iridium, and ruthenium. Examples of electrode forms include a single precious metal wire electrode, an electrode with a precious metal wire wrapped around a support, and a mesh-like precious metal electrode. It is also possible to use a metal rod other than a precious metal, such as titanium (Ti), as a support, with a precious metal coated on its surface. However, since the presence of dissimilar metal interfaces makes degradation originating from those interfaces more likely, it is preferable to use a pure precious metal or a precious metal alloy.

[0035] Details regarding the arrangement of the first electrode 201 and the second electrode 202 will be described later.

[0036] The water softening device 100 includes an electrode cleaning circuit in which the first electrode is connected to the negative electrode and the second electrode is connected to the positive electrode.

[0037] The outer peripheral diaphragm 216 is a permeable membrane that partitions the neutralization chamber 210 and the water supply unit 204, allowing softened water to pass through. The inner surface of the outer peripheral diaphragm 216 covers the outer surface of the neutralization chamber 210 and is in contact with the outer surface of the neutralization chamber 210. In addition, the outer surface of the outer peripheral diaphragm 216 covers the inner surface of the water supply unit 204 and is in contact with the inner surface of the water supply unit 204. This partitions the neutralization chamber 210 and the water supply unit 204, allowing the softened water generated in the neutralization chamber to pass through. Note that "covering" means that the membrane is located around the object, and it is not necessary to completely enclose the object.

[0038] The upper surfaces of the water intake section 203, the water softening chamber 209, the inner circumferential diaphragm 215, the neutralization chamber 210, and the outer circumferential diaphragm 216 are covered by the lid 208.

[0039] The lid portion 208 has a non-permeable structure, and for example, a plate-shaped resin can be used. The lid portion 208 is in contact with the upper surfaces of the water intake section 203, the water softening chamber 209, the inner circumferential diaphragm 215, the neutralization chamber 210, and the outer circumferential diaphragm 216, and covers each upper surface, thereby separating each upper surface from the water supply section 204, which will be described later. This prevents water from flowing out of each upper surface into the water supply section 204. In other words, the lid portion 208 can form a water flow in which raw water flowing in from the water intake section inlet 207 passes through the water intake section 203, the water softening chamber 209, the inner circumferential diaphragm 215, and the neutralization chamber 210, and is sent out from the side surface of the outer circumferential diaphragm 216 to the side space 204a of the water supply section 204.

[0040] The water supply unit 204 supplies softened water discharged from the neutralization chamber 210 to the water supply unit outlet 206, which is located above the top of the neutralization chamber 210. The central axis of the water supply unit 204 coincides with the central axis I of the casing 109. The water supply unit 204 is provided with an air vent valve 205 for removing air from inside the casing 109. The water supply unit 204 includes a side space 204a and an upper space 204b.

[0041] The side space 204a is a cylindrical space that surrounds the neutralization chamber 210, located on the outer periphery of the casing 109 with respect to its central axis I. The side space 204a is in contact with the outer surface of the outer peripheral diaphragm 216 on its inner cylindrical side and with the inner surface of the casing 109 on its outer side. In other words, the side space 204a is a space provided between the inner surface of the casing 109 and the outer surface of the outer peripheral diaphragm 216. In a direction parallel to the central axis I, the total length of the side space 204a is greater than the total length of the neutralization chamber 210, and when the bottom surfaces of the side space 204a and the neutralization chamber 210 are placed on the same plane, the top surface of the side space 204a protrudes above the top surface of the neutralization chamber 210.

[0042] The upper space 204b is a cylindrical space provided above the top surfaces of the water intake section 203, the water softening chamber 209, the inner circumferential diaphragm 215, the neutralization chamber 210, and the outer circumferential diaphragm 216. The upper space 204b has a cylindrical top surface that contacts the inner wall of the top surface of the casing 109, and a cylindrical bottom surface that contacts the outer wall of the top surface of the lid 208. In addition, the cylindrical outer surface of the upper space 204b contacts the inner surface of the side space 204a.

[0043] The water supply outlet 206 is located on the top surface of the casing 109 and discharges the water from the water supply unit 204 to the outside of the water softener 100. The central axis of the water supply outlet 206 coincides with the central axis I of the casing 109. The water supply outlet 206 is connected in communication with the water softener supply pipe 105. Return to Figure 1.

[0044] The soft water supply pipe 105 is a pipe that connects the water supply outlet 206 to the soft water supply destination, and is equipped with a soft water conductivity measuring unit 102 and a water volume measuring unit 103 along its flow path. A drain pipe 107 branches off from the soft water supply pipe 105 partway along its flow path. A soft water supply pipe on / off valve 106 is provided on the soft water supply pipe 105 downstream of the branching point with the drain pipe 107.

[0045] The soft water conductivity measuring unit 102 calculates the total ion concentration of the soft water discharged from the water supply outlet 206. The calculated total ion concentration information of the soft water is transmitted to the control unit 110, which will be described later.

[0046] Any instrument capable of measuring water resistance can be used as the raw water conductivity measuring unit 101 and the softened water conductivity measuring unit 102 without any problems.

[0047] The drainage pipe 107 is a pipe that branches off from the softened water supply pipe 105 upstream of the softened water supply pipe shut-off valve 106, and is used for draining water during the regeneration process. The drainage pipe is equipped with a drainage pipe shut-off valve 108 on its flow path. In this embodiment, a drain pipe 115 is also provided as a pipe for draining water. In this embodiment, drainage is described as being from the drain pipe 115, i.e., from the water guide section 203, but a configuration in which drainage is performed from the drainage pipe 107 is also possible.

[0048] The water volume measuring unit 103 is a component that measures the amount of water passed through the water softening device 100, and can use equipment such as a water volume meter capable of measuring the cumulative water volume. The measured water volume information is transmitted to the control unit 110, which will be described later.

[0049] The control unit 110 controls the execution of the water softening process, regeneration process, wastewater treatment process, cleaning process, and electrode cleaning process, which will be described later. The control unit 110 can be implemented as hardware, such as a computer's CPU (Central Processing Unit), and as software, such as a computer program. Therefore, these functional blocks can be implemented in various forms by combining hardware and software. The control unit 110 includes an adsorption amount estimation unit 111, a storage unit 112, and a timing unit 113.

[0050] The adsorption amount estimation unit 111 calculates the total amount of ions adsorbed on the water softener 100 using the total ion concentration of the raw water calculated from the raw water conductivity measurement unit 101, the total ion concentration of the softened water calculated from the softened water conductivity measurement unit 102, and the total amount of water passed through measured by the water volume measurement unit 103.

[0051] The storage unit 112 stores each piece of information transmitted to the control unit 110 and each piece of information calculated by the control unit 110.

[0052] The timing unit 113 measures the elapsed time since the start of the regeneration process, or more specifically, the elapsed time since the start of energizing the first electrode 201 and the second electrode 202.

[0053] The positions of the first electrode 201 and the second electrode 202 will be explained in more detail using Figure 4. Figure 4 is a cross-sectional view showing the positions of the first and second electrodes of the water softener, and is a cross-sectional view in the AA' plane shown in Figure 3. Note that the AA' plane is parallel to the bottom surface of the water softening chamber 209. In other words, the plane shown in Figure 4 is a cross-section parallel to the bottom surface of the water softening chamber 209. To put it another way, Figure 4 shows a shape that is substantially the same as the bottom surface of the water softening chamber 209. Furthermore, the notations up, down, left, and right shown in the figure are included for the sake of explanation and do not limit the orientation of the water softener 100.

[0054] The water intake section 203, the water softening chamber 209, the neutralization chamber 210, and the water supply section 204 are all configured in a substantially circular shape. Therefore, the cross-section of each is a circle, and the centers of each circle are substantially the same (point O). The water softening chamber 209, the inner circumferential diaphragm 215, the neutralization chamber 210, and the water supply section 204 are arranged in that order toward the outer circumference of a virtual circle X centered at point O. In this embodiment, the virtual circle X coincides with the outer circumference of the water supply section 204. Multiple first electrodes 201 and second electrodes 202 are provided. Here, a virtual straight line is defined.

[0055] A virtual line is a hypothetical line connecting point O, which is the center of the water intake section 203, etc., to any point on the virtual circle X. In other words, a virtual line is a hypothetical line connecting the central axis I to any point on the outer circumference of the water supply section 204. To put it another way, a virtual line is any line extending radially from point O. Figure 4 shows, as an example, a virtual line B extending to the right from point O and a virtual line C extending to the upper left from point O.

[0056] A pair of first electrodes 201 and second electrodes 202 are arranged side by side along this virtual straight line, for example, along virtual straight line B. In this embodiment, eight pairs of electrodes are arranged side by side along different virtual straight lines. Here, we define the first boundary section 401, the second boundary section 402, the intermediate section 403, and the intermediate section 404.

[0057] The first boundary section 401 is the boundary between the water intake section 203 and the water softening chamber 209. In other words, the first boundary section 401 is the inner circumferential diaphragm 215.

[0058] The second boundary section 402 is the boundary between the neutralization chamber 210 and the water supply section 204. In other words, the second boundary section 402 is the outer peripheral diaphragm 216.

[0059] The intermediate section 403 is a roughly circular imaginary line centered at point O, and is located at an equidistant distance from the first boundary section 401 and the inner circumferential diaphragm 215. In other words, the intermediate section 403 is a point on any imaginary straight line that is equal in distance from the first boundary section 401 and the inner circumferential diaphragm 215.

[0060] The intermediate section 404 is a roughly circular imaginary line centered at point O, and is located at an equidistant distance from the inner circumferential diaphragm 215 and the second boundary section 402. In other words, it is a point on any imaginary straight line that is equal in distance from the inner circumferential diaphragm 215 and the second boundary section 402.

[0061] Furthermore, the first electrode arrangement circle 407 and the second electrode arrangement circle 408 are defined.

[0062] The first electrode arrangement circle 407 is a roughly circular imaginary line centered on point O, connecting multiple first electrodes 201 (eight in this embodiment).

[0063] The second electrode arrangement circle 408 is a roughly circular imaginary line centered at point O, connecting multiple second electrodes 202 (eight in this embodiment). The second electrode arrangement circle 408 is located on the outer periphery of the first electrode arrangement circle 407.

[0064] Next, I will explain the first distance of 405 and the second distance of 406.

[0065] The first distance 405 is the distance from the first electrode 201 to the inner circumferential diaphragm 215 on any virtual straight line. In other words, the first distance 405 is the distance between the first electrode placement circle 407 and the inner circumferential diaphragm 215 on any virtual straight line.

[0066] The second distance 406 is the distance from the second electrode 202 to the inner circumferential diaphragm 215 on any virtual straight line. In other words, the second distance 406 is the distance between the second electrode placement circle 408 and the inner circumferential diaphragm 215 on any virtual straight line.

[0067] The first distance 405 is equal to or less than the second distance 406. In other words, the first distance 405 is less than or equal to the second distance 406. This arrangement reduces the irrecoverable region due to the neutralization reaction between hydrogen ions and hydroxide ions, but the details will be explained later.

[0068] In this embodiment, the first electrode 201 is provided on the outer circumference side of the intermediate portion 403. In other words, the first electrode 201 is provided in the water softening chamber 209 at a position biased toward the inner circumferential diaphragm 215 side. To put it another way, the first electrode 201 is provided with a first distance 405 between it and the inner circumferential diaphragm 215.

[0069] In this embodiment, the second electrode 202 is provided on the inner circumference side of the intermediate portion 404. In other words, the second electrode 202 is provided in the neutralization chamber 210 at a position biased toward the inner circumference diaphragm 215 side. In other words, the second electrode 202 is provided with a second distance 406 between it and the inner circumference diaphragm 215. Furthermore, this embodiment shows an example in which the first electrode 201 and the second electrode 202 are located on the same virtual straight line, but is not limited to this. The first electrode 201 and the second electrode 202 may be provided on different virtual straight lines.

[0070] In the water softening process, as described above, the raw water flows through the water softening device 100 in the following order: from the water intake section 203, through the water softening chamber 209, through the neutralization chamber 210, and through the water supply section 204. That is, the raw water flows from the center (point O) of the virtual circle X toward the outer circumference of the virtual circle X. Therefore, in the water softening chamber 209, hardness ions are adsorbed starting from the weakly acidic cation exchange resin 213 closest to the water intake section 203, and in the neutralization chamber 210, hydrogen ions are adsorbed starting from the weakly basic anion exchange resin 214 closest to the inner circumferential diaphragm 215. In other words, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are consumed from the center side of the cross-section in Figure 4.

[0071] On the other hand, in the regeneration process, hydrogen ions necessary for the regeneration of the weakly acidic cation exchange resin 213 are generated from the first electrode 201, and hydroxide ions necessary for the regeneration of the weakly basic anion exchange resin 214 are generated from the second electrode 202. Therefore, by efficiently bringing the hydrogen ions or hydroxide ions generated from the first electrode 201 and the second electrode 202 into contact with the locations where each ion exchange resin is depleted, the regeneration efficiency of the ion exchange resins by the regeneration process can be improved. The above describes the configuration of the water softening device 100.

[0072] Next, the processes of the water softening device 100 (water softening process, regeneration process, cleaning process, and electrode cleaning process) will be explained using Figures 5 and 6. Figure 5 is a diagram including an equation showing the principle of the water softening device in Embodiment 1. Figure 6 is a diagram showing the change in the hydrogen ion consumption rate by the weakly acidic cation exchange resin during the regeneration process over time.

[0073] First, we will explain the operation of the water softening device 100 in the water softening process and the principle of the water softening process.

[0074] As shown in Figures 2 and 3, in the water softening device 100, raw water flows in from the outside through the water intake inlet 207 to the lower part of the water intake section 203. The incoming raw water is sent from the lower part to the upper part of the water intake section 203 and flows out radially through holes provided in the side wall of the water intake section 203 into the casing 109. In other words, the raw water is sent from the holes in the water intake section 203 to the water softening chamber 209.

[0075] The raw water sent to the water softening chamber 209 is softened by the weakly acidic cation exchange resin 213 filled inside the water softening chamber 209. Specifically, the hardness components (calcium ions and magnesium ions) in the raw water are exchanged with hydrogen ions adsorbed on the weakly acidic cation exchange resin 213, resulting in acidic soft water containing hydrogen ions.

[0076] The acidic softened water produced in the water softening chamber 209 passes through the permeable inner circumferential diaphragm 215 and flows into the neutralization chamber 210, where it is neutralized. Specifically, hydrogen ions in the softened water are removed by adsorption onto the weakly basic anion exchange resin 214, producing neutral softened water (neutralized softened water). During this neutralization reaction, anions such as sulfate ions contained in the softened water are also adsorbed onto the weakly basic anion exchange resin 214.

[0077] The neutralized and softened water generated in the neutralization chamber 210 passes through the permeable outer diaphragm 216 and flows into the water supply section 204.

[0078] The softened water flowing into the water supply section 204 becomes an upward flow, rises within the side space 204a of the water supply section 204, and flows into the upper space 204b of the water supply section 204. The softened water flowing into the upper space 204b flows towards its center and is taken out from the water supply outlet 206 located at the center of the upper surface of the water softening device 100. In this way, raw water is softened during the water softening process.

[0079] In the water softening process, the amount of cations (more specifically, hardness ions, which are calcium ions or magnesium ions) adsorbed onto the weakly acidic cation exchange resin 213 or the weak base As the amount of anions adsorbed onto the anion exchange resin 214 increases, the resin's water softening performance deteriorates. Therefore, a regeneration process is necessary.

[0080] In the regeneration process, first, raw water flows from the raw water source into the water intake section 203 via the water intake section inlet 207, and the incoming raw water is sent to the water softening chamber 209 and the neutralization chamber 210. Next, current is applied to each electrode so that the first electrode 201, surrounded by the weakly acidic cation exchange resin 213, has a higher potential than the second electrode 202, surrounded by the weakly basic anion exchange resin 214.

[0081] As a result, a reaction that generates hydrogen ions occurs at the first electrode 201, which is the anode (see equation (5) in Figure 5), and a reaction that generates hydroxide ions occurs at the second electrode 202, which is the cathode (see equation (6) in Figure 5). In other words, hydrogen ions are generated in the water softening chamber 209, and hydroxide ions are generated in the neutralization chamber 210.

[0082] The weakly acidic cation exchange resin 213, which has adsorbed hardness components through the water softening process, undergoes an exchange reaction between hardness components and hydrogen ions when exposed to hydrogen ions. This regenerates the weakly acidic cation exchange resin 213.

[0083] Furthermore, the weakly basic anion exchange resin 214, on which anions have been adsorbed by the water softening process, undergoes an exchange reaction between the adsorbed anions and hydroxide ions when exposed to hydroxide ions. This regenerates the weakly basic anion exchange resin 214.

[0084] In the regeneration process, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are regenerated in this manner.

[0085] Here, we will add Figure 7 to explain the schematic movement of hydrogen ions and hydroxide ions during the regeneration process. Figure 7 is a schematic diagram showing the movement of hydrogen ions and hydroxide ions during the regeneration process. Note that Figure 7 omits the illustration of the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214. Also, the arrows showing the movement of hydrogen ions and hydroxide ions in the figure are examples only and do not limit the direction of movement of each ion.

[0086] As will be explained in more detail later, the general flow of the regeneration process is as follows: First, water is introduced from the water intake section 203 into the water softening chamber 209 and the neutralization chamber 210. Then, the first electrode 201 and the second electrode 202 are energized, and after a predetermined time has elapsed, the water is drained through the water intake section 203.

[0087] When current is passed through the first electrode 201 and the second electrode 202, hydrogen ions are generated from the first electrode 201 and hydroxide ions are generated from the second electrode 202, as shown in Figure 7.

[0088] The generated hydrogen ions diffuse away from the first electrode 201 due to the hydrogen ion concentration gradient or electric field. More specifically, some hydrogen ions diffuse towards the neutralization chamber 210, while other hydrogen ions diffuse towards the water supply section 203.

[0089] On the other hand, the generated hydroxide ions diffuse away from the second electrode 202 due to the hydroxide ion concentration gradient or electric field. More specifically, some hydroxide ions diffuse towards the water softening chamber 209, while other hydroxide ions diffuse towards the water supply unit 204.

[0090] At this time, hydrogen ions moving towards the neutralization chamber 210 come into contact with hydroxide ions that have diffused from the second electrode 202 side, causing a neutralization reaction. In other words, a neutralization region with low concentrations of hydrogen ions and hydroxide ions is formed between the first electrode 201 and the second electrode 202. This occurs. Within the neutralization region, there are fewer hydrogen ions and hydroxide ions necessary for the regeneration of each ion exchange resin, so the regeneration efficiency of the ion exchange resin located in this region decreases. In particular, when the pH becomes neutral, the rate of the hardness ion adsorption reaction, which is the reverse reaction of the regeneration reaction, increases for the weakly acidic cation exchange resin 213, making regeneration difficult. The neutralization region tends to form at a position that roughly bisects the distance between the first electrode 201 and the second electrode 202.

[0091] Therefore, in this embodiment, in order to suppress the decrease in regeneration efficiency, the first distance 405, which is the distance between the first electrode 201 and the inner circumferential diaphragm 215, and the second distance 406, which is the distance between the second electrode 202 and the inner circumferential diaphragm 215, are made equal.

[0092] This configuration allows the neutralization region and the inner circumferential diaphragm 215 (i.e., the region where no ion exchange resin is provided) to coincide, thus minimizing the amount of ion exchange resin located within the neutralization region. As a result, each ion exchange resin can be efficiently exposed to hydrogen ions or hydroxide ions, achieving maintenance or improvement of regeneration efficiency.

[0093] Furthermore, when the first distance 405 and the second distance 406 are equal, it is preferable that the thickness of the inner circumferential diaphragm 215 is greater than or equal to the thickness of the neutralization region. Since the thickness of the neutralization region is approximately a few millimeters (for example, 2 or 3 mm), it is quite possible to design the inner circumferential diaphragm 215 so that its thickness is greater than or equal to the thickness of the neutralization region.

[0094] This configuration reduces the amount of ion exchange resin located within the neutralization region, thereby decreasing the total amount of ion exchange resin that is difficult to regenerate and enabling more efficient regeneration.

[0095] Furthermore, in this embodiment, the first electrode 201 and the second electrode 202 are provided along the same virtual straight line.

[0096] This configuration facilitates the formation of a neutralization region on the inner circumferential diaphragm 215. As a result, as described above, the amount of ion exchange resin located within the neutralization region can be minimized, thereby improving regeneration efficiency.

[0097] Furthermore, for example, the first distance 405 may be shorter than the second distance 406. In this case, the neutralization region is formed on the outer side of the inner circumferential diaphragm 215, i.e., within the neutralization chamber 210. The weakly basic anion exchange resin 214 filled in the neutralization chamber 210 can be regenerated more easily than the weakly acidic cation exchange resin 213 filled in the water softening chamber 209. This is because the weakly basic anion exchange resin 214 has a high affinity for hydroxide ions (compared to the affinity of the weakly acidic cation exchange resin 213 for hydrogen ions), the effect of the reverse reaction during regeneration is small, and regeneration is possible even at a pH closer to neutral (alkaline).

[0098] This configuration allows for more efficient regeneration of the ion exchange resin compared to the case where the neutralization region is formed within the water softening chamber 209 having the weakly acidic cation exchange resin 213.

[0099] Furthermore, for example, the first electrode 201 may be provided on the intermediate section 403, or at a position biased toward the neutralization chamber 210 side of the intermediate section 403. In other words, the first electrode 201 may be provided in the water softening chamber 209, at a distance from the intermediate section 403 as viewed from the water guide section 203, which is also used as a drain outlet. To put it another way, the first electrode arrangement circle 407 may be provided at a position that coincides with the intermediate section 403, or at a position that is toward the neutralization chamber 210 side of the intermediate section 403.

[0100] With this configuration, when wastewater is discharged, the first electrode has a relatively high hydrogen ion concentration. This makes it possible to pass water from the vicinity of 201 through a wide area within the water softening chamber 209 (particularly the weakly acidic cation exchange resin 213 located on the water intake side of the water softening chamber 209, which is subject to significant wear). In other words, it becomes possible to efficiently expose the weakly acidic cation exchange resin 213 in the water softening chamber 209 to hydrogen ions, and as a result, the regeneration efficiency of the weakly acidic cation exchange resin 213 can be improved.

[0101] Furthermore, for example, the second electrode 202 may be provided on the intermediate section 404, or at a position biased toward the water supply section 204 side of the intermediate section 404. In other words, the second electrode 202 may be provided in the neutralization chamber 210, on the side further away from the intermediate section 404 when viewed from the water supply section 203, which is also used as a drain outlet. To put it another way, the second electrode arrangement circle 408 may be provided at a position that coincides with the intermediate section 404, or at a position that is on the water supply section 204 side of the intermediate section 404. More specifically, since the water softening chamber 209 and the neutralization chamber 210 are cylindrical, their volumes depend on the square of the radius of the base. Also, the water softening device 100 has a water softening chamber 209 on the inside and a neutralization chamber 210 on the outside. Therefore, when the volumes of the water softening chamber 209 and the neutralization chamber 210 are the same, the distance from the first boundary 401 to the inner circumferential diaphragm 215 (thickness of the water softening chamber 209) on any imaginary straight line in the cross-section of the water softening device 100 tends to be longer than the distance from the inner circumferential diaphragm 215 to the outer circumferential diaphragm 216 (thickness of the neutralization chamber 210). This tendency is particularly pronounced when the diameter of the water guide section 203 is small. If the first electrode 201 is placed on the intermediate portion 403 between the first boundary and the inner circumferential diaphragm 215, and the first distance 405 is the same length as the second distance 406, then, based on the relationship between the first boundary 401, the inner circumferential diaphragm 215, and the outer circumferential diaphragm 216 described above, the second electrode placement circle 408 will be outside the intermediate portion 404. In other words, if the first electrode 201 is located on the intermediate section 403 along any imaginary straight line in the cross-section of the water softening device 100, the second electrode 202 is located at a position that is biased toward the water supply section 204 side of the intermediate section 404.

[0102] This configuration allows water near the second electrode 202, which has a relatively high hydroxide ion concentration, to be passed through a wide area within the neutralization chamber 210 (particularly the weakly basic anion exchange resin 214 located on the water softening chamber 209 side of the neutralization chamber 210, which is subject to significant wear). In other words, the weakly basic anion exchange resin 214 within the neutralization chamber 210 can be efficiently exposed to hydroxide ions, and as a result, the regeneration efficiency of the weakly basic anion exchange resin 214 can be improved.

[0103] Furthermore, for example, the second electrode 202 may be positioned more towards the inner circumferential diaphragm 215 than the intermediate section 404. In other words, the second electrode 202 may be positioned in the neutralization chamber 210, further away from the intermediate section 404 as viewed from the water supply section 204. More specifically, if the first electrode 201 is positioned more towards the inner circumferential diaphragm 215 than the intermediate section 403, and the first distance 405 is the same length as the second distance 406, then the second electrode 202 will also be positioned more towards the inner circumferential diaphragm 215.

[0104] This configuration increases the distance from the second electrode 202 to the water supply section 204 compared to the case where the second electrode 202 is located closer to the water supply section 204 than the intermediate section 404. In other words, the thickness of the weakly basic anion exchange resin 214 increases for hydroxide ions diffusing towards the water supply section 204. As a result, the probability that hydroxide ions diffusing towards the water supply section 204 are consumed by the regeneration reaction of the weakly basic anion exchange resin 214 increases, suppressing the rise in pH of the water supply section 204 and the formation of solids within the water supply section 204. Consequently, the amount of water required to wash away solids can be kept to a minimum.

[0105] Here, "solid" primarily refers to calcium carbonate. More specifically, some hardness ions may move from the water softening chamber 209 to the water supply unit 204. At this time, if hardness ions are present in the water supply unit 204 and the pH of the water in the water supply unit 204 rises, the hardness ions will precipitate as calcium carbonate. Excess water is needed to wash away the precipitated solid. Therefore, it is desirable to suppress the generation of solids, that is, the increase in pH in the water supply section.

[0106] Next, the detailed operations in the regeneration process will be described.

[0107] In the regeneration process, the water softening device 100 sets the regeneration time based on the conductivity of the raw water or softened water before and after passing water through the casing 109, or the amount of water passed through the casing 109.

[0108] At the start of the water softening process, the raw water conductivity measurement unit 101 is activated to measure the conductivity of the raw water flowing through the raw water supply pipe 104. Also, the softened water conductivity measurement unit 102 is activated to measure the conductivity of the softened water flowing through the softened water supply pipe 105. Furthermore, the water volume measurement unit 103 measures the volume of water that has passed through the casing 109. The measured conductivity of the raw water, conductivity of the softened water, and water volume are transmitted to the control unit 110 and stored in the storage unit 112.

[0109] The ions removed in the water softening chamber 209 are mainly hardness ions of Mg 2+ , Ca 2+ . The ions removed in the neutralization chamber 210 are mainly anions of HCO3 - , Cl - , SO4 2- [[ID=Z6]]]. According to the principle of electrical neutrality, the number of moles of cations adsorbed in the water softening chamber 209 is equal to the number of moles of anions adsorbed in the neutralization chamber 210. Therefore, the difference between the conductivities measured by the raw water conductivity measurement unit 101 and the softened water conductivity measurement unit 102 is derived from the total amount of Mg salts and Ca salts removed by the water softening device 100. Thus, since the conductivity difference is the value of the removed ion concentration, it can cope with fluctuations in the water quality of the raw water and softened water, and the adsorption amount can be accurately calculated.

[0110] The adsorption amount estimation unit 111 estimates the amount of ions adsorbed on the water softener 100. Specifically, it calculates the difference between the conductivity of the raw water and the conductivity of the softened water, which is stored in the memory unit 112. This difference is the ion concentration adsorbed on the water softener 100. The adsorption amount estimation unit 111 multiplies the ion concentration obtained as the difference by the total amount of water passed through, as measured by the water volume measurement unit 103. This estimates the amount of ions adsorbed on the water softener 100 during the regeneration process.

[0111] Here, the estimated adsorbed ions are removed from the water softener 100, and the current value and energizing time required to regenerate the water softener 100 are explained using Figures 5 and 6. In the regeneration process, 1 mole of electrons is converted to H + 1 mole, 1 mole of electrons from OH - One mole is produced. Also, in order to release one mole of hardness ions from the resin, H + Two moles are needed. Therefore, the number of moles of ions adsorbed in the water softening chamber 209, and the amount of H required for resin regeneration. + The relationship between current value and time is expressed by equation (2) in Figure 5.

[0112] The control unit 110 determines the current value and energizing time required for the regeneration of the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 based on the number of moles of adsorbed ions estimated by the adsorption amount estimation unit 111 and equation (2) in Figure 5.

[0113] In the water softening device 100, it is preferable to change the applied current value as the regeneration process progresses. The reason for this is explained below. As the regeneration process progresses, each ion adsorbed during the water softening process is released into the water from the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214, so the ion concentration in the water increases. In other words, as the elapsed time since the start of the regeneration process increases, the conductivity of the water in the water softening device 100 becomes higher than at the start of energization, and the voltage decreases. On the other hand, at the start of energization, the ion concentration of the water in the water softening device 100 is low, so the voltage is high. Therefore, if the current value is kept constant from the start of energization, the voltage will be high at the start of energization and will gradually decrease as the energization time progresses.

[0114] In the final stages of the regeneration process, (R-COO) in equations (3) and (4) in Figure 5 - )2Ca 2 + , R3-NH + Cl ― As the concentration of hydrogen ions decreases, the regeneration rate slows down. As a result, as shown in Figure 6, the consumption rate of the added hydrogen ions decreases, and the conversion rate decreases. When the consumption rate is low, even if hydrogen ions or hydroxide ions in a concentration greater than that that can be consumed by the resin are added to the weakly acidic cation exchange resin 213 or the weakly basic anion exchange resin 214, the added hydrogen ions and hydroxide ions will react with each other without reacting with the ions in the resin, resulting in a loss.

[0115] In other words, based on the voltage characteristics in the initial stages of the regeneration process described above, it is preferable to gradually increase the current when applying current, rather than immediately increasing it to the current value determined by the adsorption amount estimation unit 111. This allows the voltage to be kept low, thus reducing power consumption. Furthermore, in the later stages of the regeneration process, it is preferable to gradually decrease the current based on the reaction characteristics of the resin. This suppresses the reaction of excess ions together, reduces wasted current, and thus reduces power consumption.

[0116] A timing unit 113 is used to control the time-dependent changes in the applied current. The memory unit 112 stores a first reference value, which sets the current to its maximum value, and a second reference value, which sets the current to begin decreasing from its maximum value, as reference times indicating the timing for changing the current. The first reference value is set to approximately 30 minutes to 1 hour from the start of energization. The second reference value is set to a later time than the first reference value, and 30 minutes to 1 hour before the end of energization. Since the current and time required for the regeneration process are determined by the hardness of the adsorbed material as shown in equation (1) in Figure 5, increasing 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 requires increasing the maximum current value or the regeneration time.

[0117] The timing unit 113 measures the elapsed time from the start of current application to the first electrode 201 and the second electrode 202. When the elapsed time measured by the timing unit 113 reaches a first reference value, the control unit 110 stops increasing the applied current value and maintains the current value. Subsequently, when the elapsed time measured by the timing unit 113 reaches a second reference value, the control unit 110 decreases the applied current value. The increase in the current value from the start of energization to the first reference value, or the decrease in the current value from the second reference value to the end of energization, may be changed linearly or in a stepwise manner.

[0118] In the regeneration process, a determined current value is applied to the first electrode 201 and the second electrode 202 for a determined energizing time, and the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are regenerated.

[0119] After the regeneration process is complete, ions released from the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are present in high concentrations in the water softening chamber 209 and the neutralization chamber 210. Therefore, it is necessary to perform a cleaning operation inside the water softening device 100. If the cleaning is insufficient, the remaining ions may mix with the water during the water softening process, potentially resulting in insufficient water softening. For this reason, the cleaning process is performed after the regeneration process is complete.

[0120] During the washing process, in the water softening device 100, the water softening supply pipe valve 106 is closed and the drain pipe valve 108 is opened, causing the water in the water softening chamber 209 and neutralization chamber 210 to be drained outside the water softening device 100 via the drain pipe 107. Then, raw water flows in from the raw water supply pipe 104, making the regeneration process ready to resume.

[0121] When the end of the washing process is determined by time, the washing time, which is the time from the start to the end of the washing process, is made longer than the residence time, which is the time from when the raw water flows into the water softening chamber 209 until it flows out of the neutralization chamber 210. This allows the water containing a large amount of desorbed hardness ions present in the water softening chamber 209 to be discharged and replaced with raw water.

[0122] During the regeneration process, solid calcium carbonate deposits accumulate on the electrode surface of the second electrode 202. An increase in calcium carbonate deposition on the electrode surface leads to problems such as increased voltage during current application and difficulty in removing the calcium carbonate from the electrode surface. Therefore, it is necessary to periodically perform an electrode cleaning process to remove the calcium carbonate from the cathode surface.

[0123] In the electrode cleaning process, the first electrode 201 is connected to the negative electrode and the second electrode 202 is connected to the positive electrode; in other words, the electrode cleaning is performed by reversing the polarity of the electrodes compared to the regeneration process. This operation causes H to escape from the second electrode 202. + H is generated, and the calcium carbonate on the surface of the second electrode 202 is H + It reacts and dissolves. The electrode cleaning process is performed during or after the regeneration process.

[0124] As described above, the water softening device 100 repeatedly performs maintenance on the water softening device 100 through a water softening process, a water regeneration process, a cleaning process, and an electrode cleaning process.

[0125] The present invention has been described above based on embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible for each component or combination of processes, and that such modifications also fall within the scope of the present invention.

[0126] An overview of one aspect of this disclosure is as follows: (Item 1) A water softening chamber (209) having a weakly acidic cation exchange resin (213) that generates soft water from raw water containing hardness components, A neutralization chamber (210) having a weakly basic anion exchange resin (214) for neutralizing the softened water, A diaphragm (215) separates the water softening chamber (209) and the neutralization chamber (210) in a manner that allows the softened water to pass through. A water intake section (203) for introducing the raw water from the outside into the water softening chamber, A water supply unit (204) that sends the neutralized softened water generated in the neutralization chamber (210) to the outside, A first electrode (201) is provided in the water softening chamber (209) surrounded by the weakly acidic cation exchange resin (213) and acts as an anode when the weakly acidic cation exchange resin (213) is regenerated, The system comprises a second electrode (202) provided within the neutralization chamber (210) surrounded by the weakly basic anion exchange resin (214), which acts as a cathode during the regeneration of the weakly basic anion exchange resin (214), From the water guide section (203), which has a central axis perpendicular to the bottom surface of the water softening chamber (209), the water softening chamber (209), the diaphragm (215), the neutralization chamber (216), and the water supply section (204) are arranged in the order of the water softening chamber (209), toward the outer circumference of a circle centered on the central axis. The first electrode (201) is provided with a first distance (405) between it and the diaphragm (215) in the outer peripheral direction. The second electrode (202) is provided with a second distance (406) between it and the diaphragm (215) in the outer peripheral direction. The first distance (405) is less than or equal to the second distance (406). Water softener (100). (Item 2) The water softening device (100) described in item 1, wherein the first distance (405) and the second distance (406) are the same distance. (Item 3) The first electrode (201) is provided at a position in the outer peripheral direction that bisects the distance from the outer circumference of the water guide section (203) to the diaphragm (215), as described in item 1 of the water softening apparatus (1 00). (Item 4) The second electrode (202) is provided in the neutralization chamber (210) at a position biased toward the water supply unit (204), as described in item 3, for the water softening device (100). (Item 5) The first electrode (210) is provided in the water softening chamber (209) at a position biased toward the diaphragm (215) side, as described in item 1, in the water softening apparatus (100). (Item 6) The second electrode (202) is provided in the neutralization chamber (210) at a position biased toward the diaphragm (215) side, as described in item 5, for the water softening device (100). (Item 7) The water softening device (100) according to item 1, wherein a pair of the first electrodes (201) and the second electrode (202) are provided along a virtual straight line connecting the central axis and the outer circumference of the water supply unit (204). (Item 8) The first electrode (201) is provided in multiple locations on the same radius, and is part of the water softening device (100) described in item 1. [Industrial applicability]

[0127] The water softening device according to the present invention can reduce the frequency of wastewater discharge or eliminate wastewater discharge altogether, thereby reducing the amount of wastewater discharged. As a secondary effect, it can also shorten the regeneration time and increase the electrode life, making it useful as a water softening device. [Explanation of Symbols]

[0128] 100 Water softener 101 Raw water conductivity measurement section 102 Soft water conductivity measurement section 103 Water measurement section 104 Raw water supply pipe 105 Soft water supply pipe 106 Soft water supply pipe shut-off valve 107 Drainage piping 108 Drainpipe shut-off valve 109 Casing 110 Control Unit 111 Adsorption amount estimator 112 Storage section 113 Timing section 114 Drain valve 115 Drain pipe 201 First electrode 202 Second electrode 203 Water intake section 204 Water supply section 204a Side space 204b Upper space 205 Air vent valve 206 Water supply section outlet 207 Water intake entrance 208 Lid 209 Water softening room 210 Neutralization room 211 First space 212 Second space 213 Weakly acidic cation exchange resin 214 Weakly basic anion exchange resin 215 Inner diaphragm 216 Peripheral diaphragm 401 First boundary 402 Second boundary 403 Middle section 404 Middle section 405 First distance 406 Second distance 407 First electrode arrangement circle 408 Second electrode arrangement circle

Claims

1. A water softening chamber equipped with a weakly acidic cation exchange resin that generates soft water from raw water containing hardness components, A neutralization chamber having a weakly basic anion exchange resin to neutralize the softened water, A diaphragm separates the water softening chamber and the neutralization chamber, allowing the softened water to pass through. A water intake unit for introducing the raw water from the outside into the water softening chamber, A water supply unit that sends the neutralized and softened water generated in the aforementioned neutralization room to the outside, A first electrode is provided within the water softening chamber, surrounded by the weakly acidic cation exchange resin, and acts as an anode during the regeneration of the weakly acidic cation exchange resin. The neutralization chamber is provided surrounded by the weakly basic anion exchange resin and includes a second electrode that acts as a cathode during the regeneration of the weakly basic anion exchange resin, From the water supply section having a central axis perpendicular to the bottom surface of the water softening chamber, the water softening chamber, the diaphragm, the neutralization chamber, and the water supply section are arranged in the order of the outer circumference of a circle centered on the central axis. The first electrode is provided with a first distance between it and the diaphragm in the outer peripheral direction, The second electrode is provided with a second distance between it and the diaphragm in the outer peripheral direction, The aforementioned first distance is less than or equal to the aforementioned second distance. Water softener.

2. The water softening apparatus according to claim 1, wherein the first distance and the second distance are the same distance.

3. The water softening apparatus according to claim 1, wherein the first electrode is provided at a position that bisects the distance from the outer circumference of the water guiding section to the diaphragm in the outer circumference direction.

4. The water softening apparatus according to claim 3, wherein the second electrode is provided in the neutralization chamber at a position biased toward the water supply section.

5. The water softening apparatus according to claim 1, wherein the first electrode is provided in the water softening chamber at a position biased toward the diaphragm side.

6. The water softening apparatus according to claim 5, wherein the second electrode is provided in the neutralization chamber at a position biased toward the diaphragm side.

7. The water softening apparatus according to claim 1, wherein a pair of the first electrode and the second electrode are provided along a virtual straight line connecting the central axis and the outer circumference of the water supply section.

8. The water softening apparatus according to claim 1, wherein the first electrodes are provided in multiple locations on the same radius.

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