Water softener

Abstract

To provide a water softener enabling efficient regeneration of resin.SOLUTION: A water softener 100 includes: a water softening chamber 209; a neutralization chamber 210; an inner peripheral side diaphragm 215; a water conveyance part 203 located at the inner periphery of the water softening chamber 209 and supplying raw water to the water softening chamber 209; a water supply part 204 supplying neutralized soft water generated in the neutralization chamber 210 to the outside; and a control part 110. The control part 110 executes: a water softening process of making the raw water flow in from the water conveyance part 203 and conducting water to the water softening chamber 209 and the neutralization chamber 210 in this order to obtain the neutralized soft water; a regeneration process of regenerating a weakly acidic cation-exchange resin 213 using hydrogen ions; and a drainage process of discharging cation discharged from the weakly acidic cation-exchange resin 213 by the regeneration process from the water softening chamber 209, and discharging the anion emitted from a weakly basic anion-exchange resin 214 from the neutralization chamber 210. In the drainage process, the water containing the cation is drained from the water conveyance part 203.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a water softening device that uses an ion exchange resin. [Background technology]

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

[0003] Furthermore, in order to solve the problems of the workload involved in salt replenishment and the performance problem of not being able to obtain soft water if salt replenishment is not carried out appropriately, water softening 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 a basic configuration in which two types of resins, a weakly acidic cation exchange resin and a weakly basic anion exchange resin, are mixed together, and neutral soft water can be obtained by using a bipolar membrane (a membrane in which a cation exchange resin membrane and an anion exchange resin membrane are joined: 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 the prior art, when a certain amount of hardness ions is adsorbed onto 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 membrane and resin chamber between the electrodes. The BP membrane or ion exchange resin chamber has an interface between the cation exchange resin and the anion exchange resin. When a voltage is applied to this interface, water molecules are split and H + and OH - is generated. The generated H + The weakly acidic cation exchange resin was - The weakly basic anion exchange resin can be regenerated by [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-163890 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technique described in Patent Document 1 has a problem in that the hardness ions released from the ion exchange resin are re-adsorbed onto the ion exchange resin, which tends to inhibit the reaction during regeneration of the resin.

[0008] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a water softening device that allows efficient regeneration of resin. [Means for solving the problem]

[0009] In order to solve the above problems, the water softening device of the present invention includes a water softening chamber containing a weakly acidic cation exchange resin to produce soft water from raw water containing hardness components, a neutralization chamber located on the outer periphery of the water softening chamber and containing a weakly basic anion exchange resin to neutralize the soft water, a diaphragm separating the water softening chamber and the neutralization chamber to allow soft water to pass through, a water conveying section located on the inner periphery of the water softening chamber to supply raw water to the water softening chamber, a water conveying section to convey the neutralized soft water produced in the neutralization chamber to the outside, and a control section to control the regeneration of the weakly acidic cation exchange resin. The control section controls the water softening process to produce neutralized soft water by introducing raw water from the water conveying section and passing the raw water through the water softening chamber and then the neutralization chamber, the regeneration process to regenerate the weakly acidic cation exchange resin using hydrogen ions produced by electrolysis of water after the water softening process has been performed for a predetermined period of time, and the control section controls the water softening chamber to discharge cations released from the weakly acidic cation exchange resin during the regeneration process from the water softening chamber and neutralize anions released from the weakly basic anion exchange resin. The water discharged from the chamber is then discharged through the water conveyance section, thereby achieving the intended purpose. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a water softening device that allows efficient regeneration of resin. [Brief explanation of the drawings]

[0011] [Figure 1] Schematic diagram of a water softening device according to the first embodiment. [Figure 2] 1 is a perspective view of a water softening device according to a first embodiment; [Figure 3] 1 is a cross-sectional view of a water softening device according to a first embodiment; [Figure 4] FIG. 1 includes a formula showing the principle of the water softening device according to the first embodiment. [Figure 5] Figure showing the time course of hydrogen ion consumption by weakly acidic cation exchange resin during the regeneration process [Figure 6] FIG. 1 is a perspective view of an example of a water softening device according to a first embodiment; [Figure 7] FIG. 10 is a diagram showing the relationship between the amount of wastewater and hardness one hour after the start of regeneration in an example according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0013] (Embodiment 1) A water softening device 100 according to a first embodiment of the present invention will be described with reference to Figures 1, 2, and 3. Figure 1 is a schematic diagram showing the configuration of the water softening device 100 according to the first embodiment of the present invention. Figure 2 is a perspective view showing the configuration of the water softening device 100 according to the first embodiment of the present invention. Figure 3 is a cross-sectional view showing the configuration of the water softening device 100 according to the first embodiment of the present invention. Note that Figures 1 to 3 conceptually show each element of the water softening device 100. Furthermore, in Figure 2, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are omitted.

[0014] The water softening apparatus 100 is an apparatus that produces neutral soft water from raw water containing hardness components supplied from an external source. The raw water is water (water to be treated) introduced into the water softening apparatus 100 through a raw water supply pipe 104 (described later), such as well water or tap water. The raw water contains hardness components (calcium ions and magnesium ions). By performing a water softening process to soften raw water using the water softening apparatus 100, neutral soft water with reduced hardness can be obtained from raw water with high hardness, making soft water usable even in areas with high raw water hardness. After performing the water softening process for a certain period of time, the water softening apparatus 100 also performs a regeneration process to regenerate the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 (described later). The 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 107, a softened water supply pipe 105, a bypass pipe 114, a housing 109, and a control unit 110.

[0016] Raw water supply pipe 104 is a pipe that connects a raw water source, such as a water supply, to a water conveyance section inlet 207 (described later), and is provided with raw water conductivity measuring section 101 on its flow path. Raw water supply pipe 104 is connected to drainage pipe 107 downstream of raw water conductivity measuring section 101 and upstream of the connection point with water conveyance section inlet 207. A drainage pipe opening / closing valve 108 is provided at the connection point between raw water supply pipe 104 and drainage pipe 107.

[0017] The raw water conductivity measuring unit 101 calculates the total ion concentration of the raw water that has flowed into the raw water supply pipe 104. Information on the calculated total ion concentration of the raw water is sent to the control unit 110, which will be described later.

[0018] The drain pipe 107 is a pipe branched off from the soft water supply pipe 105 on the upstream side of the soft water supply pipe on-off valve 106, and is a pipe through which water is drained during a drainage process described later.

[0019] The drain pipe on-off valve 108 is a valve provided at the connection between the raw water supply pipe 104 and the drain pipe 107. By opening and closing the drain pipe on-off valve 108, it is possible to switch between sending raw water from the water supply source to the water conveying section inlet 207 via the raw water supply pipe 104, or discharging water from inside the housing 109 (described later) to the outside of the water softening device 100 via the raw water supply pipe 104 and the drain pipe 107.

[0020] The soft water supply pipe 105 is a pipe that connects the water supply outlet 206 (described later) to the destination of the soft water supply, and is provided with a soft water conductivity measuring unit 102, a water volume measuring unit 103, and a soft water supply pipe opening / closing valve 106 on its flow path.

[0021] The soft water conductivity measuring unit 102 calculates the total ion concentration of the soft water sent out from the water sending unit outlet 206 (see FIG. 2). The calculated total ion concentration information of the soft water is sent to the control unit 110, which will be described later.

[0022] Any device capable of measuring the resistance of water can be used as the raw water conductivity measuring unit 101 and the soft water conductivity measuring unit 102 without any problems.

[0023] The water volume measuring unit 103 is a component that measures the volume of water passed through the water softening device 100, and can use a device such as a water meter that can measure the cumulative volume of water. The measured water volume information is sent to the control unit 110, which will be described later.

[0024] The softened water supply pipe on-off valve 106 is a valve provided in the softened water supply pipe 105. By opening and closing the softened water supply pipe on-off valve 106, it is possible to switch between supplying softened water to the outside and not supplying softened water to the outside.

[0025] The bypass piping 114 is a pipe that branches off from the raw water supply pipe 104 upstream of the connection between the raw water supply pipe 104 and the drainage pipe 107, and connects to the softened water supply pipe 105 upstream of the softened water supply pipe on-off valve 106. Through the bypass piping 114, raw water is supplied from a raw water supply source to the water conveyance outlet 206 during the drainage process and the cleaning process, which will be described later. The bypass piping 114 is provided with a bypass piping on-off valve 115 on its flow path.

[0026] The bypass pipe on-off valve 115 is a valve provided on the bypass pipe 114. By opening and closing the bypass pipe on-off valve 115, raw water can be supplied from the water supply source to the water supply unit outlet 206 via the bypass pipe 114 and the soft water supply pipe 105.

[0027] The housing 109 is a hollow cylindrical member, and the raw water is softened and the ion exchange resin is regenerated within the housing 109 .

[0028] 2 and 3, in the hollow space of casing 109, a water conveying section 203, a water softening chamber 209, a neutralization chamber 210, and a water conveying section 204 are provided in this order from the side closest to a central axis I connecting the top and bottom surfaces of casing 109 toward the outer periphery. A water conveying section inlet 207 is provided at the center of the bottom surface of casing 109, i.e., on the central axis I. A water conveying section outlet 206 is provided at the center of the top surface of casing 109, i.e., on the central axis I. The central axis I of casing 109 coincides with the central axes of water conveying section 203, water softening chamber 209, neutralization chamber 210, and water conveying section 204, respectively.

[0029] The water conveying section inlet 207 is provided on the bottom surface of the housing 109 and supplies raw water to the water conveying section 203. The central axis of the water conveying section inlet 207 coincides with the central axis I of the housing 109. The water conveying section inlet 207 is connected in communication with the raw water supply pipe 104.

[0030] The water conveying section 203 is a cylindrical member, and its lower end is connected to a water conveying section inlet 207. The water conveying section 203 conveys raw water into the water softening device 100 and supplies it to the water softening chamber 209. The water conveying section 203 may be a tube such as a pipe having an internal space, or a water-permeable membrane.

[0031] The water conveying section 203 is configured to allow raw water introduced into the water softening device 100 to flow uniformly through the water softening chamber 209 and the neutralization chamber 210. Specifically, the water conveying section 203 is provided in the center of the housing 109, and the outer periphery of the water conveying section 203 is in contact with the water softening chamber 209; in other words, the water conveying section 203 is located on the central axis I. The water conveying section 203 is also provided from the bottom to the top of the water softening chamber 209 and the neutralization chamber 210, more precisely from the bottom to the top, 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 conveying section 203 has a plurality of holes on its side surface, and raw water is sent from these holes in the circumferential direction from the central axis I of the housing 109, i.e., to the water softening chamber 209. Furthermore, it is preferable that the plurality of holes be uniformly provided in the circumferential direction on the side surface of the water conducting section 203. With such a configuration, raw water introduced into the device can be uniformly flowed through the water softening chamber 209 and the neutralization chamber 210. Therefore, raw water is supplied evenly to the weakly acidic cation exchange resin 213 particles packed in the water softening chamber 209 and the weakly basic anion exchange resin 214 particles packed in the neutralization chamber 210, allowing efficient use of the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 as a whole.

[0032] The plurality of holes formed on the side surface of the water conducting section 203 are smaller in diameter than the particle diameter of the weakly acidic cation exchange resin particles, and since the lower limit of the particle diameter of the weakly acidic cation exchange resin is around 0.3 mm, the diameter of the holes formed on the surface of the water conducting section 203 is smaller than that. This makes it possible to prevent the ion exchange resin from leaking out of the water softening chamber 209 without impeding the permeation of water.

[0033] The water softening chamber 209 is a cylindrical space (first space 211) that is provided inside the casing 109 on the outer circumferential side of the water conducting 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 contacts the water conducting section 203 on the inner surface side of its cylindrical shape, contacts an inner circumferential diaphragm 215, which is a cylindrical membrane that is water permeable, on the outer surface side, and contacts the lid section 208 on the top surface. The water softening chamber 209 is filled with the weakly acidic cation exchange resin 213, and is provided with a first electrode 201.

[0034] The weakly acidic cation exchange resin 213 is an ion exchange resin having a carboxyl group, and may be, for example, one having a methacrylic acid skeleton or one having an acrylic acid skeleton. In this embodiment, a resin having an acrylic acid skeleton is used as the weakly acidic cation exchange resin 213.

[0035] The first electrode 201 is not energized during the water softening process, and acts as an anode during 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 in 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 the top to the bottom along the entire periphery. However, the weakly acidic cation exchange resin 213 usually has a spherical shape, and it is necessary to ensure a water passage for the raw water. For this reason, the weakly acidic cation exchange resin 213 is in contact with the surface of the first electrode 201 without any gaps. Instead of the above, a state in which the first electrode 201 is arranged over the entire circumference in a state of partial contact also falls under the category of "the first electrode 201 is surrounded by the weakly acidic cation exchange resin 213."

[0036] The upper end of the first electrode 201 is located below the water surface in the water softening chamber 209 at the start of the regeneration process. Multiple first electrodes 201 are provided in the water softening chamber 209, with the distance between adjacent first electrodes 201 being equal. The material for the first electrode 201 can be a precious metal or a precious metal alloy. This is because the precious metal acts as a catalyst for water electrolysis and does not dissolve even in acidic conditions. Examples of precious metal materials include platinum, iridium, and ruthenium. The electrode can take the form of a single precious metal wire electrode, an electrode with a precious metal wire wound around the outer periphery of a support, or a mesh-shaped precious metal electrode. A support made of a metal other than a precious metal, such as titanium (Ti), coated with a precious metal can also be used. However, because the presence of a dissimilar metal interface is prone to degradation at the interface, it is preferable to use a single precious metal or a precious metal alloy.

[0037] The inner diaphragm 215 is a water-permeable membrane that partitions the water softening chamber 209 and the neutralization chamber 210 so that softened water can pass through. The inner surface of the inner diaphragm 215 covers the outer surface of the water softening chamber 209 and is in contact with the outer surface of the water softening chamber 209. The outer surface of the inner diaphragm 215 covers the inner surface of the neutralization chamber 210 and is in contact with the inner surface of the neutralization chamber 210. In this way, the inner diaphragm 215 partitions the water softening chamber 209 and the neutralization chamber 210 so that the acidic soft water generated in the water softening chamber 209 can pass through. Note that "covering" only requires that the membrane be positioned around the object, and does not necessarily require that the membrane completely enclose the object.

[0038] The neutralization chamber 210 is a cylindrical space (second space 212) that is provided inside the casing 109 on the outer circumferential side of the water softening chamber 209 with respect to the central axis I of the casing 109, and contains 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 inner surface of the neutralization chamber 210 contacts the outer surface of the inner circumferential diaphragm 215, the outer surface of the neutralization chamber 210 contacts the inner surface of the outer circumferential diaphragm 216, which is a cylindrical membrane that is water permeable, and the upper surface of the neutralization chamber 210 contacts the lid 208. The neutralization chamber 210 is filled with the weakly basic anion exchange resin 214, and is provided with a second electrode 202.

[0039] 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 having a higher proportion of tertiary amine than quaternary amine is used.

[0040] The second electrode 202 is not energized during the water softening process and serves as a cathode during 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 in the neutralization chamber 210. Here, "surrounded" refers to a state in which 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 along the entire periphery. However, like the weakly acidic cation exchange resin 213, the weakly basic anion exchange resin 214 is typically spherical, and a water passage for the raw water (strictly speaking, acidic soft water) must be secured. For this reason, the weakly basic anion exchange resin 214 does not necessarily contact the surface of the second electrode 202 without any gaps. A state in which the weakly basic anion exchange resin 214 is arranged around the entire periphery with partial contact also falls under the category of "the second electrode 202 being surrounded by the weakly basic anion exchange resin 214."

[0041] The upper end of the second electrode 202 is located below the water surface in the neutralization chamber 210 at the start of the regeneration process. A plurality of second electrodes 202 are provided in the neutralization chamber 210 so that the distance between adjacent second electrodes 202 is equal. The material of the second electrode 202 can be a precious metal or a precious metal alloy. This is because the second electrode 202 does not contain a precious metal. This is because the presence of precious metals allows them to act as a catalyst for water electrolysis and prevents elution even under acidic conditions. Examples of precious metal materials include platinum, iridium, and ruthenium. Electrode forms include a single precious metal wire electrode, an electrode with a precious metal wire wound around the outer periphery of a support, and a mesh-shaped precious metal electrode. A form in which a metal rod other than a precious metal, such as titanium (Ti), is used as the support and the surface is coated with a precious metal can also be used. However, since the presence of an interface between different metals is likely to cause deterioration due to the interface, it is preferable to use a precious metal or a precious metal alloy alone.

[0042] The first electrode 201 is provided as a pair with the second electrode 202, and the pair of first electrode 201 and second electrode 202 is provided on the same radius of the housing 109. This allows the distance between the first electrode 201 and the second electrode 202 to be shorter than when the pair of electrodes are not on the same radius, and makes it possible to suppress an increase in power consumption due to an increase in voltage.

[0043] The water softening device 100 includes a circuit for cleaning electrodes, which connects the first electrode to the negative electrode and the second electrode to the positive electrode.

[0044] The outer peripheral diaphragm 216 is a water-permeable membrane that partitions the space between the neutralization chamber 210 and the water supply section 204 so that soft water can 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. The outer surface of the outer peripheral diaphragm 216 also covers the inner surface of the water supply section 204 and is in contact with the inner surface of the water supply section 204. This allows the soft water produced in the neutralization chamber to pass through, thereby partitioning the space between the neutralization chamber 210 and the water supply section 204. Note that "covering" only requires that the membrane be positioned around the object, and does not necessarily require that the membrane completely encase the object.

[0045] The upper surfaces of the water conveying section 203 , the water softening chamber 209 , the inner diaphragm 215 , the neutralization chamber 210 , and the outer diaphragm 216 are covered by the lid section 208 .

[0046] The lid 208 has a water-impermeable structure and can be made of, for example, a plate-shaped resin. The lid 208 contacts and covers the upper surfaces of the water conveying section 203, the water softening chamber 209, the inner diaphragm 215, the neutralization chamber 210, and the outer diaphragm 216, thereby separating each upper surface from the water conveying section 204, which will be described later. This prevents water from flowing out of each upper surface into the water conveying section 204. In other words, the lid 208 forms a water flow in which raw water flowing in from the water conveying section inlet 207 passes through the water conveying section 203, the water softening chamber 209, the inner diaphragm 215, and the neutralization chamber 210, and is sent out from the side surface of the outer diaphragm 216 to the side space 204a of the water conveying section 204.

[0047] The water supply unit 204 supplies the softened water sent out from the neutralization chamber 210 to a water supply unit outlet 206 provided 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 housing 109. The water supply unit 204 is provided with an air vent valve 205 that vents air from inside the housing 109. The water supply unit 204 includes a side space 204a and an upper space 204b.

[0048] The side space 204a is a cylindrical space that is provided on the outer circumferential side of the neutralization chamber 210 with respect to the central axis I of the housing 109 and surrounds the neutralization chamber 210. The inner surface of the side space 204a contacts the outer surface of the outer circumferential diaphragm 216, and the outer surface contacts the inner surface of the housing 109. In other words, the side space 204a is a space that is provided between the inner surface of the housing 109 and the outer surface of the outer circumferential diaphragm 216. In the 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 aligned on the same plane, the top surface of the side space 204a protrudes above the top surface of the neutralization chamber 210.

[0049] The upper space 204b includes the water conveying section 203, the water softening chamber 209, the inner periphery side diaphragm 215, the neutralization chamber 21 Upper space 204b is a cylindrical space provided above the top surfaces of side space 204a, outer diaphragm 216, and outer peripheral diaphragm 216. The cylindrical top surface of upper space 204b contacts the inner top wall of housing 109, and the cylindrical bottom surface of upper space 204b contacts the outer top wall of lid 208. The cylindrical outer surface of upper space 204b contacts the inner surface of side space 204a.

[0050] The water supply unit outlet 206 is provided on the top surface of the housing 109, and discharges water from the water supply unit 204 to the outside of the water softening device 100. The central axis of the water supply unit outlet 206 coincides with the central axis I of the housing 109. The water supply unit outlet 206 is connected in communication with the softened water supply pipe 105. Return to FIG. 1.

[0051] The control unit 110 controls the execution of each of the processes described below: water softening process, regeneration process, drainage process, cleaning process, and electrode cleaning process. The control unit 110 can be realized as hardware using elements and mechanical devices such as a computer CPU (Central Processing Unit), and as software using a computer program or the like. Therefore, these functional blocks can be realized in various forms by combining hardware and software. The control unit 110 includes an adsorption amount estimation unit 111, a memory unit 112, and a timer unit 113.

[0052] The adsorption amount estimation unit 111 calculates the total amount of ions adsorbed in the water softening device 100 using the total ion concentration of the raw water calculated by the raw water conductivity measurement unit 101, the total ion concentration of the softened water calculated by the softened water conductivity measurement unit 102, and the total amount of water flowing measured by the water volume measurement unit 103.

[0053] The storage unit 112 stores the various pieces of information transmitted to the control unit 110 and the various pieces of information calculated by the control unit 110 .

[0054] The timer 113 measures the time elapsed since the start of the regeneration process, more specifically, the time elapsed since the start of energization of the first electrode 201 and the second electrode 202 .

[0055] The water softening device 100 has the above configuration.

[0056] Next, the processes of the water softening device 100 (water softening process, regeneration process, drainage process, cleaning process, and electrode cleaning process) will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram including formulas showing the principle of the water softening device in the first embodiment. Fig. 5 is a diagram showing the change over time in the rate of hydrogen ion consumption by the weakly acidic cation exchange resin during the regeneration process.

[0057] First, the operation of the water softening device 100 in the water softening process and the principle of the water softening process will be described.

[0058] 2 and 3, in the water softening device 100, raw water flows from the outside into the lower part of the water conveying section 203 through the water conveying section inlet 207. The flowing raw water is sent from the lower part to the upper part of the water conveying section 203 and flows out in the radial direction of the housing 109 from holes provided in the side wall of the water conveying section 203. In other words, the raw water is sent out from the holes in the water conveying section 203 to the water softening chamber 209.

[0059] 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. In detail, hardness components (calcium ions, magnesium ions) in the raw water are exchanged with hydrogen ions adsorbed on the weakly acidic cation exchange resin 213, and the raw water becomes acidic soft water containing hydrogen ions.

[0060] The acidic softened water produced in the water softening chamber 209 passes through the inner diaphragm 215, which is a water-permeable membrane, and flows into the neutralization chamber 210, where it is neutralized. The weakly basic anion exchange resin 214 adsorbs the sulfate ions and other anions contained in the softened water, thereby producing neutral softened water (neutralized softened water). During this neutralization reaction, the weakly basic anion exchange resin 214 also adsorbs the sulfate ions and other anions contained in the softened water.

[0061] The neutralized soft water produced in the neutralization chamber 210 passes through the outer peripheral diaphragm 216, which is a water-permeable membrane, and flows into the water supply section 204.

[0062] The softened water that flows into the water supply section 204 flows upward, 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 that flows into the upper space 204b flows toward the center of the upper space 204b and is taken out from the water supply section outlet 206 provided in the center of the top surface of the water softening device 100. In this way, raw water is softened in the water softening process.

[0063] In the water softening process, if the amount of cations (more specifically, hardness ions such as calcium ions or magnesium ions) adsorbed onto the weakly acidic cation exchange resin 213 or the amount of anions adsorbed onto the weakly basic anion exchange resin 214 increases, the resin's water softening performance will decrease, and a regeneration process will be required.

[0064] In the regeneration process, first, raw water flows from a raw water supply source into the water conveying section 203 via the water conveying section inlet 207, and the flowing raw water is sent to the water softening chamber 209 and the neutralization chamber 210. Next, electricity is passed through 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.

[0065] As a result, a reaction that produces hydrogen ions (see formula (5) in FIG. 4) occurs at the first electrode 201, which is the anode, and a reaction that produces hydroxide ions (see formula (6) in FIG. 4) occurs at the second electrode 202, which is the cathode. In other words, hydrogen ions are produced in the water softening chamber 209, and hydroxide ions are produced in the neutralization chamber 210.

[0066] When the weakly acidic cation exchange resin 213, which has absorbed hardness components during the water softening process, is exposed to hydrogen ions, an exchange reaction between the hardness components and the hydrogen ions occurs, thereby regenerating the weakly acidic cation exchange resin 213.

[0067] Furthermore, when the weakly basic anion exchange resin 214, which has adsorbed anions during the water softening process, is exposed to hydroxide ions, an exchange reaction between the adsorbed anions and the hydroxide ions occurs, thereby regenerating the weakly basic anion exchange resin 214.

[0068] In this manner, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are regenerated in the regeneration process.

[0069] 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 through the casing 109 or the amount of water that has passed through the casing 109 .

[0070] At the start of the water softening process, the raw water conductivity measuring unit 101 is activated and measures the conductivity of the raw water flowing through the raw water supply pipe 104. The soft water conductivity measuring unit 102 is also activated and measures the conductivity of the soft water flowing through the soft water supply pipe 105. Furthermore, the water volume measuring unit 103 measures the volume of water that has flowed through the housing 109. The measured raw water conductivity, soft water conductivity, and water volume are sent to the control unit 110 and stored in the memory unit 112.

[0071] The ions removed in the water softening chamber 209 are mainly Mg 2+ , Ca 2+ The hardness ions and ions removed in the neutralization chamber 210 are mainly HCO3 - , Cl - , SO4 2- The anion of According to the principle of conductivity, 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 conductivity measured by the raw water conductivity measuring unit 101 and the softened water conductivity measuring unit 102 is derived from the total amount of Mg salts and Ca salts removed by the water softening device 100. In this way, because the conductivity difference is the value of the concentration of removed ions, it is possible to respond to changes in the water quality of the raw water and softened water, and the amount of adsorption can be calculated with high accuracy.

[0072] The adsorption amount estimation unit 111 estimates the amount of ions adsorbed in the water softening device 100. Specifically, it calculates the difference between the conductivity of the raw water stored in the memory unit 112 and the conductivity of the softened water. This difference is the concentration of ions adsorbed in the water softening device 100. The adsorption amount estimation unit 111 multiplies the ion concentration obtained as the difference by the total amount of water passing through measured by the water amount measurement unit 103. In this way, the amount of ions adsorbed in the water softening device 100 during the regeneration process is estimated.

[0073] Here, the current value and current application time required to remove the estimated adsorbed ions from the water softener 100 and regenerate the water softener 100 will be described. In the regeneration process, 1 mole of electrons is converted into H + 1 mole, 1 mole of electrons to OH - To release 1 mole of hardness ions from the resin, + Therefore, the number of moles of ions adsorbed in the water softening chamber 209 and the number of moles of H required for resin regeneration are + The relationship between the current value and time is expressed by equation (2) in FIG.

[0074] The control unit 110 determines the current value and current application time required to regenerate the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 from the number of adsorbed ion moles estimated by the adsorption amount estimation unit 111 and equation (2) in Figure 4.

[0075] In the water softening apparatus 100, it is preferable to change the applied current value as the regeneration process progresses. The reason for this is as follows: As the regeneration process progresses, the ions adsorbed during the water softening process are released into the water from the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214, causing the ion concentration in the water to increase. In other words, as the time elapses from the start of the regeneration process, the conductivity of the water in the water softening apparatus 100 becomes higher than at the start of power application, and the voltage decreases. On the other hand, at the start of power application, the ion concentration of the water in the water softening apparatus 100 is low, so the voltage is high. Therefore, if the current value is kept constant from the start of power application, the voltage will be high at the start of power application and will gradually decrease as power application time passes.

[0076] At the end of the regeneration process, (R-COO - )2Ca 2+ , R3-NH + Cl ― As the concentration of hydrogen ions decreases, the regeneration rate slows down. As a result, as shown in Figure 5, the consumption rate of the input hydrogen ions decreases, and the conversion rate drops. When the consumption rate is low, even if hydrogen ions or hydroxide ions at a concentration greater than the concentration that can be consumed by the resin are input to the weak acidic cation exchange resin 213 or the weak basic anion exchange resin 214, the input hydrogen ions and hydroxide ions will react with each other without reacting with the ions in the resin, resulting in a loss.

[0077] In other words, based on the voltage characteristics at the beginning 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 keeps the voltage low, thereby reducing power consumption. Furthermore, based on the reactivity characteristics of the resin, it is preferable to gradually decrease the current toward the end of the regeneration process. This makes it possible to prevent excess ions from reacting with each other, reducing current waste and suppressing power consumption.

[0078] In order to measure such a change in the applied current over time, a timer unit 113 is used. The memory unit 112 stores a first reference value that maximizes the current as a reference time indicating the timing for changing the current. The second reference value, which starts decreasing from the maximum value, is memorized. The first reference value is set to about 30 minutes to 1 hour after the start of current application. The second reference value is set to a time later than the first reference value and 30 minutes to 1 hour before the end of current application. Since the current and time required for the regeneration process are determined by the adsorbed hardness as shown in formula (1) in Figure 4, if the time from the start of current application to the first reference value or the time from the end of current application to the second reference value is increased, the maximum current value or regeneration time must be increased.

[0079] 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. Thereafter, when the elapsed time measured by the timing unit 113 reaches a second reference value, the control unit 110 decreases the applied current value. Note that the increase in the current value from the start of current application to the first reference value, or the decrease in the current value from the second reference value to the end of current application, may be changed linearly or in a stepwise manner.

[0080] In the regeneration process, a determined current value is applied to the first electrode 201 and the second electrode 202 for a determined current application time, and the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are regenerated.

[0081] As described above, the regeneration process gradually increases the concentrations of various ions, including hardness ions such as calcium ions and magnesium ions released from the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214, over time. In particular, as the hardness ion concentration increases, the equilibrium shifts to the left in the reaction equation shown in (3) of Figure 4, i.e., toward the weakly acidic cation exchange resin 213 again adsorbing the hardness ions. Therefore, to efficiently perform the regeneration, it is important to suppress the increase in calcium ion concentration in the water contained in the housing 109. On the other hand, if all the water contained in the housing 109 is discharged and raw water is supplied to the housing 109 to perform the regeneration process, the ion concentration in the raw water is lower than the ion concentration in the water present in the housing 109 during the regeneration process, which is unfavorable for the regeneration process. Therefore, to efficiently proceed with the regeneration process, it is preferable to reduce the hardness ion concentration without significantly reducing the total ion concentration in the housing 109. For this reason, a drainage process is performed to discharge some of the water in the housing 109.

[0082] In the drainage process, it is important to discharge an appropriate amount of water, in order to reduce the concentration of hardness ions while maintaining the electrolyte concentration in the water softening chamber 209 and the neutralization chamber 210 at a certain value or higher (for example, the electrolyte concentration of the raw water or higher) in preparation for carrying out the regeneration process again after the drainage process, thereby suppressing a decrease in the efficiency of the regeneration process.

[0083] Here, the amount of water discharged during the discharge process is preferably smaller than the sum of the volume of the water conveying section 203, the volume of the water softening chamber 209, and the volume of the neutralization chamber 210, and more preferably the volume of the part in the water softening chamber 209 other than that occupied by the weakly acidic cation exchange resin 213 is smaller than the sum of the volumes of the part in the neutralization chamber 210 other than that occupied by the weakly basic anion exchange resin 214. Also, it is preferable that the volume is larger than the volume of the part in the water softening chamber 209 other than that occupied by the weakly acidic cation exchange resin.

[0084] Here, the drainage will be explained in detail using specific numerical examples with reference to Figs. 6 and 7. Fig. 6 shows an example in which the volumes of the water conveying section 203, the water softening chamber 209, and the neutralization chamber 210 are larger than those in Fig. 2. Specifically, the volumes of the water conveying section 203, the water softening chamber 209, and the neutralization chamber 210 in Fig. 6 are approximately 900 mL, approximately 1300 mL, and approximately 1600 mL, respectively. Fig. 7 is a diagram showing the relationship between the amount of drainage and the hardness contained in the drainage after one hour of execution of the regeneration process in the example shown in Figs. 6 and 7. In each case, hard water (hardness: 300 mg / L) in an amount equivalent to the amount of wastewater is added after drainage. Although the volumes of the water softening chamber 209 and the neutralization chamber 210 are as described above, the water softening chamber 209 is filled with a weakly acidic cation exchange resin 213, and the neutralization chamber 210 is filled with a weakly basic anion exchange resin 214. Therefore, the amount of water filled in the water softening chamber 209 and the neutralization chamber 210 is less than the respective volumes. In other words, water exists only in the areas other than the spaces occupied by the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214. Experimental testing revealed that the amount of water filled in each space was approximately one-third the volume of the water softening chamber 209 or the neutralization chamber 210. Therefore, in the example of FIG. 6, the volume of the water softening chamber 209 is 1300 mL, and there is approximately 400 mL of water in the water softening chamber 209. The volume of the neutralization chamber 210 is 1600 mL, and there is approximately 500 mL of water in the neutralization chamber 210. According to FIG. 7, the hardness of the wastewater reaches its maximum when the wastewater volume is approximately 550 mL. Even when the wastewater volume is 820 mL, the hardness is more than twice that of the water with a hardness of 300 mg / L that is being injected. Therefore, when the wastewater volume in the wastewater process is in this range, the hardness during regeneration can be efficiently reduced. In other words, when the wastewater volume in the wastewater process is greater than the volume of the portion occupied by the weakly acidic cation exchange resin 213 in the water softening chamber 209, the ion concentration in the water softening chamber 209 can be efficiently reduced, which is preferable. Furthermore, if the amount of wastewater is greater than the sum of the volume of the portion occupied by the weakly acidic cation exchange resin 213 in the water softening chamber 209 and the volume of the portion occupied by the weakly basic anion exchange resin 214 in the neutralization chamber 210, the ion concentrations in the water softening chamber 209 and the neutralization chamber 210 can be efficiently reduced, which is preferable. From FIG. 7 , it can be seen that even when the amount of wastewater exceeds 1600 mL, the hardness of the injected water is higher than 300 mg / L. Therefore, even when the amount of wastewater is greater than the volume of the water softening chamber 209, the hardness can be efficiently reduced during regeneration. However, it is preferable that the maximum amount of wastewater in the drainage process is smaller than the sum of the volumes of the water softening chamber 209 and the neutralization chamber 210.

[0085] Here, specific flow paths and the like in the drainage process will be described. During the regeneration process, the drain pipe on-off valve 108 and the bypass pipe on-off valve 115 are both closed. At the start of the drainage process, the drain pipe on-off valve 108 is set to a state in which the drain pipe 107 and the water conveying section 203 are connected, and the bypass pipe on-off valve 115 is opened. This allows raw water to be injected into the casing 109. At this time, it is preferable that the drain flow rate be smaller than the flow rate during the water softening process, since this allows the water in the casing 109 to be discharged without agitating. Furthermore, the amount of drainage can be measured using any known method without any particular limitations. For example, a method of determining a specified amount of drainage using the output of the water volume measuring section 103 or a method using the output of the timing section 113 can be used.

[0086] The timing to start the drainage process can be determined based on, for example, the elapsed time from the start of the regeneration process. Specifically, when the elapsed time from the start of the regeneration process measured by the timer 113 exceeds a certain time, the control unit 110 performs the drainage process. This reduces the ion concentration of the water in the water softener 100 and improves the regeneration efficiency of the regeneration process. It is preferable to perform the drainage process multiple times until the regeneration is completed. This allows the regeneration process to be performed with a low hardness ion concentration, which is preferable, improving the regeneration efficiency. When determining the timing to start 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 of the regeneration process and to decrease the frequency of the drainage process in the latter half of the regeneration process. As shown in Figure 5, the reaction efficiency is high until the middle of the regeneration process, so the change in the desorbed ion concentration over time is large. On the other hand, the reaction efficiency is low in the latter half of the regeneration process, so the change in the desorbed ion concentration over time is small. Therefore, the frequency of drainage in the latter half of the regeneration process can be less than in the middle of the regeneration process. In other words, it is preferable to increase the time interval between drainage processes as the regeneration process progresses. Considering both the reduction of wastewater volume and the reduction of reaction inhibition caused by desorbed ions, the interval between drainage is preferably about 30 minutes. For example, drainage should be performed once every 20 minutes until the middle of the regeneration process. The process is executed, and in the latter half of the regeneration process, the drain process is executed once every 40 minutes. When the drainage is completed, the control unit 110 closes the drain pipe opening / closing valve 108 and the bypass pipe opening / closing valve 115. This makes it possible to execute the regeneration process again.

[0087] Furthermore, the direction of the discharge is also important in the discharge process. The weakly acidic cation exchange resin 213 in the water softening chamber 209 has a biased distribution of the amount of hardness components adsorbed. The weakly acidic cation exchange resin 213 on the water conveying section 203 side is the first to receive raw water, so it is prone to adsorb hardness components. On the other hand, the weakly acidic cation exchange resin 213 on the inner periphery diaphragm 215 side is downstream of the weakly acidic cation exchange resin 213 on the water conveying section 203 side, so it tends to adsorb fewer hardness components than the weakly acidic cation exchange resin 213 on the water conveying section 203 side. In the regeneration process, protons are supplied to the weakly acidic cation exchange resin 213 in this state, and a regeneration treatment is performed. During this regeneration treatment, the adsorbed hardness components are released from the weakly acidic cation exchange resin 213. Therefore, in the water softening chamber 209, more hardness components are released on the water conveying section 203 side than on the inner periphery diaphragm 215 side, and therefore water with a high concentration of hardness components in the water softening chamber 209 is located on the water conveying section 203 side. Therefore, in the drainage process, by draining the water in the water softening chamber 209 from the water conveying section 203 side, the concentration of hardness components in the water softening chamber 209 can be reduced with a minimum amount of drainage.

[0088] Furthermore, if, in the drainage process, the water in the water softening chamber 209 is passed through the inner diaphragm 215 and then the neutralization chamber 210 in the same order as in the water softening process, and then sent to the outside through the water conveying section 204, there is a possibility that the hardness components that have been desorbed from the weakly acidic cation exchange resin 213 in the regeneration process will be re-adsorbed onto the weakly acidic cation exchange resin 213. The reason for this will be explained in detail below. As described above, the weakly acidic cation exchange resin 213 on the inner diaphragm 215 side tends to adsorb a smaller amount of hardness components than the weakly acidic cation exchange resin 213 on the water conveying section 203 side, and therefore tends to release a smaller amount of hardness components in the regeneration process. In this state, if water is passed through the inner diaphragm 215 and then the neutralization chamber 210, in the water softening chamber 209, the water on the water conveying section 203 side, which contains a relatively large amount of hard components, may flow into the inner diaphragm 215 side, which contains a relatively small amount of hard components, and may be re-adsorbed by the weakly acidic cation exchange resin 213 on the inner diaphragm 215 side. Therefore, from the viewpoint of improving regeneration efficiency, it is preferable to discharge the water in the following order: water conveying section 204, neutralization chamber 210, inner diaphragm 215, water softening chamber 209, and water conveying section 203, rather than the following order: water conveying section 203, water softening chamber 209, inner diaphragm 215, neutralization chamber 210, and water conveying section 204. In other words, when discharging water in the drainage process, it is preferable to discharge water from the water conveying section 203 through the drainage pipe 107. Furthermore, it is preferable that the raw water is supplied into the housing 109 from the water supply outlet 206 via the bypass piping 114 .

[0089] After the drainage process is completed, the regeneration process is started again, or if the regeneration is sufficient, the regeneration process is terminated.

[0090] After the regeneration process is complete, high concentrations of ions released from the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 remain 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 will mix with the water during the water softening process, which may result in insufficient water softening. Therefore, a cleaning process is performed after the regeneration process is complete.

[0091] In the cleaning process, in the water softening device 100, the softened water supply pipe on-off valve 106 is closed, and the bypass pipe on-off valve 115 and the drain pipe on-off valve 108 are opened. This causes the water in the water softening chamber 209 and the neutralization chamber 210 to be drained outside the water softening device 100 via the drain pipe 107. Then, raw water flows in from the water conveyance section through the bypass pipe 114, making the water softening process possible.

[0092] When the end of the washing process is determined by time, it is preferable that the washing time, which is the time from the start to the end of the washing process, is longer than the residence time, which is the time from when the raw water flows into the neutralization chamber 210 until it flows out of the water softening chamber 209. This allows water containing a large amount of desorbed hardness ions present in the water softening chamber 209 to be discharged, and the water in the water softening chamber 209 to be replaced with raw water.

[0093] During the regeneration process, solids such as calcium carbonate adhere to the electrode surface of the second electrode 202. If the amount of calcium carbonate deposited on the electrode surface increases, problems such as an increase in voltage when current is applied and difficulty in peeling calcium carbonate from the electrode surface occur. Therefore, it is preferable to periodically perform an electrode cleaning process to remove calcium carbonate from the cathode surface.

[0094] 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 polarity is reversed from that in the regeneration process, and the electrode cleaning is performed. + is generated, and calcium carbonate on the surface of the second electrode 202 reacts with H + The electrode cleaning process may be carried out during the regeneration process or after the regeneration process is completed.

[0095] As described above, in the water softening apparatus 100, the softening of raw water by the water softening process, the regeneration process, the drainage process, the cleaning process, and the maintenance of the water softening apparatus 100 by the electrode cleaning process are repeatedly performed.

[0096] As described above, the water softening device 100 according to this embodiment can provide the following effects.

[0097] (1) The water softening device 100 includes a water softening chamber 209 that contains a weakly acidic cation exchange resin 213 and produces soft water from raw water containing hardness components, a neutralization chamber 210 that is located on the outer periphery of the water softening chamber 209 and contains a weakly basic anion exchange resin 214 and neutralizes the soft water, an inner diaphragm 215 that partitions the space between the water softening chamber 209 and the neutralization chamber 210 to allow soft water to pass through, a water conveying section 203 that is located on the inner periphery of the water softening chamber 209 and supplies raw water to the water softening chamber 209, a water conveying section 204 that conveys the neutralized soft water produced in the neutralization chamber 210 to the outside, and a control section 110 that controls the regeneration of the weakly acidic cation exchange resin 213. The control unit 110 executes a water softening process in which raw water is introduced from the water conveying unit 203 and passed through the water softening chamber 209, the inner diaphragm 215, and the neutralization chamber 210 in this order to obtain neutralized soft water, a regeneration process in which, after the water softening process has been executed for a predetermined period of time, the weak acid cation exchange resin 213 is regenerated using hydrogen ions generated by electrolysis of water, and a cleaning process in which cations released from the weak acid cation exchange resin 213 by the regeneration process are discharged from the water softening chamber 209 and anions released from the weak basic anion exchange resin 214 are discharged from the neutralization chamber 210. In the cleaning process, water containing cations is discharged from the water conveying unit 203.

[0098] With this configuration, the water can be discharged from the weakly acidic cation exchange resin 213 side, which has a high concentration of hardness components. Therefore, the re-adsorption of cations onto the weakly acidic cation exchange resin 213 during the cleaning process can be suppressed, resulting in a water softening apparatus 100 that can improve regeneration efficiency.

[0099] (2) In the water softening device 100, the amount of water discharged in the drainage process is smaller than the sum of the volume of the water conveying section 203, the volume of the water softening chamber 209, and the volume of the neutralization chamber 210. If the amount of water discharged is set in this manner, it is possible to prevent more water than necessary from being discharged in the drainage process, and the water softening device 100 can be made to waste less water.

[0100] (3) In the water softening device 100, the weakly acidic cation exchange resin 213 is filled in the water softening chamber 209. The weakly basic anion exchange resin 214 is filled in the neutralization chamber 210. The amount of discharged water in the discharge process is preferably smaller than the sum of the volume of the water softening chamber 209 other than that occupied by the weakly acidic cation exchange resin 213 and the volume of the neutralization chamber 210 other than that occupied by the weakly basic anion exchange resin 214. By setting the amount of discharged water in this manner, the water in the water softening chamber 209 and the neutralization chamber 210 can be discharged, and the cations desorbed from the weakly acidic cation exchange resin 213 and the anions desorbed from the weakly basic anion exchange resin 214 in the regeneration process can be discharged outside the water softening apparatus 100. Therefore, in the next water softening process, it is possible to prevent cations and anions from remaining in the water softening chamber 209 and reduce the possibility of hardness components precipitating.

[0101] (4) In the water softening device 100, the amount of water discharged in the drainage process is larger than the volume of the water softening chamber 209 other than the portion occupied by the weakly acidic cation exchange resin 213. This allows the water present in the water softening chamber 209 to be drained, ensuring the minimum amount of water discharged. Therefore, the water softening device 100 can be configured to improve regeneration efficiency while suppressing the amount of water discharged.

[0102] (5) In the water softening apparatus 100, the draining process is preferably performed multiple times during the regeneration process. This allows draining to be performed multiple times at appropriate times during the regeneration process, thereby improving the resin regeneration efficiency in the regeneration process.

[0103] (6) The water softening device 100 includes a first electrode 201 that is disposed in the water softening chamber 209 and surrounded by the weakly acidic cation exchange resin 213, and acts as an anode during regeneration of the weakly acidic cation exchange resin 213, and a second electrode 202 that is disposed in the neutralization chamber 210 and surrounded by the weakly basic anion exchange resin 214, and acts as a cathode during regeneration of the weakly basic anion exchange resin 214. In the regeneration process, a voltage is applied between the first electrode 201 and the second electrode 202, and execution of the drainage process is determined based on the applied voltage. In this way, drainage can be performed when the ion concentration in the water softening chamber 209 increases, and the resin regeneration efficiency in the regeneration process can be improved.

[0104] (7) In the water softening device 100, raw water supplied into the casing 109 during the drainage process flows in from the water conveying section 204. This allows for a water flow in which raw water flows in from the water conveying section 204 during the drainage process and water in the casing 109 is discharged from the water conveying section 203, thereby suppressing re-adsorption of cations onto the weakly acidic cation exchange resin 213.

[0105] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present invention.

[0106] In the first embodiment, the timing to start the drainage process is determined based on the elapsed time from the start of the regeneration process, but this is not limited to this. For example, the execution of the drainage process may be determined based on the voltage applied between the first electrode and the second electrode during the regeneration process. Even in this case, the same effect as in the first embodiment can be obtained. [Industrial Applicability]

[0107] The water softening device according to the present invention is useful as an efficiently recyclable water softening device, etc. [Explanation of symbols]

[0108] 100 Water softener 101 Raw water conductivity measurement unit 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 on-off valve 107 Drainage piping 108 Drain pipe on-off valve 109 Case 110 control section 111 Adsorption amount estimator 112 Storage section 113 Timing section 114 Bypass piping 115 Bypass piping on / off valve 201 First electrode 202 Second electrode 203 Water Convection Section 204 Water supply section 204a Side space 204b Upper space 205 Air vent valve 206 Water supply section outlet 207 Water Conduit 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 Outer diaphragm

Claims

1. a water softening chamber having a weakly acidic cation exchange resin for producing soft water from raw water containing hardness components; a neutralization chamber located on the outer periphery of the water softening chamber, which has a weakly basic anion exchange resin and neutralizes the softened water; a diaphragm that separates the water softening chamber and the neutralization chamber so that the softened water can pass through; a water conveying section located on the inner periphery of the water softening chamber and supplying the raw water to the water softening chamber; a water supply unit that supplies the neutralized soft water produced in the neutralization chamber to the outside; a control unit for controlling the regeneration of the weakly acidic cation exchange resin; The control unit a water softening process in which the raw water is introduced from the water conveying section and passed through the water softening chamber and the neutralization chamber in this order to obtain the neutralized soft water; a regeneration process in which, after the water softening process has been carried out for a predetermined period of time, the weakly acidic cation exchange resin is regenerated using hydrogen ions generated by electrolysis of water; a draining process for draining the cations released from the weakly acidic cation exchange resin by the regeneration process from the water softening chamber and the anions released from the weakly basic anion exchange resin by the regeneration process from the neutralization chamber; In the drainage process, A water softening device that discharges the water containing the cations from the water conveying section.

2. 2. The water softening apparatus according to claim 1, wherein the amount of water discharged in the water discharge process is smaller than the sum of the volume of the water conveying section, the volume of the water softening chamber, and the volume of the neutralization chamber.

3. 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, 2. The water softening apparatus according to claim 1, wherein the amount of wastewater discharged in the drainage process is smaller than the sum of the volume of the water softening chamber other than the portion occupied by the weakly acidic cation exchange resin and the volume of the water neutralization chamber other than the portion occupied by the weakly basic anion exchange resin.

4. The weakly acidic cation exchange resin is filled in the water softening chamber, 2. The water softening apparatus according to claim 1, wherein the amount of drainage in the drainage process is greater than the volume of the water softening chamber other than the volume of the portion occupied by the weakly acidic cation exchange resin.

5. The water softening apparatus of claim 1 , wherein the draining process is performed multiple times during the regeneration process.

6. a first electrode that is disposed in the water softening chamber and surrounded by the weakly acidic cation exchange resin, and that acts as an anode during regeneration of the weakly acidic cation exchange resin; a second electrode that is disposed in the neutralization chamber and surrounded by the weakly basic anion exchange resin, and that acts as a cathode during regeneration of the weakly basic anion exchange resin; The water softening apparatus according to claim 5, wherein the regeneration process involves applying a voltage between the first electrode and the second electrode, and determining whether the drainage process is to be performed based on the applied voltage.

7. The water softening apparatus according to claim 1 , wherein raw water supplied during the drainage process flows in from the water conveyance section side.

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