Water softener

Abstract

To provide a water softener enabling drainage control and efficient resin reproduction at the time of reproduction.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 around 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 first electrode 201 functioning as the anode when regenerating a weakly acidic cation-exchange resin 213. The water softening chamber 209, the inner peripheral side diaphragm 215, the neutralization chamber 210 and the water supply part 204 are disposed in this order toward an outer peripheral direction of a circle around a center axis from a water conveyance part 203 having a center axis perpendicular to the bottom surface of the water softening chamber 209. The first electrode 201 is disposed at a position deviated closer to the water conveyance part 203 in the water softening chamber 209.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 present 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, in the technology described in Patent Document 1, the hardness ions released from the ion exchange resin are re-adsorbed onto the ion exchange resin, which tends to inhibit the reaction during resin regeneration. Therefore, in order to discharge the released hardness ions, regeneration must be performed while passing water through the resin. This water passing operation poses a problem in that the amount of wastewater discharged during resin regeneration increases.

[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 can suppress wastewater generation during regeneration and efficiently regenerate resin. [Means for solving the problem]

[0009] In order to solve the above problems, the water softening device of the present invention comprises a water softening chamber containing a weakly acidic cation exchange resin to produce soft water from raw water containing hardness components, a neutralization chamber containing a weakly basic anion exchange resin to neutralize the soft water, a diaphragm that separates the water softening chamber and the neutralization chamber to allow soft water to pass through, a water conveying section that introduces raw water from the outside into the water softening chamber, a water conveying section that conveys the neutralized soft water produced in the neutralization chamber to the outside, a first electrode that is surrounded by the weakly acidic cation exchange resin in the water softening chamber and acts as an anode when the weakly acidic cation exchange resin is regenerated, and a second electrode that is surrounded by the weakly basic anion exchange resin in the neutralization chamber and acts as a cathode when the weakly basic anion exchange resin is regenerated. The water softening chamber, diaphragm, neutralization chamber, and water conveying section are arranged in this order from the center toward the outer periphery of a circle centered on the central axis, and the first electrode is arranged in a position biased toward the water conveying section in the water softening chamber. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a water softening device that can suppress wastewater during regeneration and efficiently regenerate 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] 2 is a cross-sectional view showing the AA′ cross section of the water softening device according to the first embodiment. [Figure 5] FIG. 1 includes a formula showing the principle of the water softening device according to the first embodiment. [Figure 6] Figure showing the time course of hydrogen ion consumption by weakly acidic cation exchange resin during the regeneration process 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 casing 109, a softened 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 source of raw water, such as a water supply, to a water conveyance inlet 207, which will be described later, and is provided with a raw water conductivity measuring unit 101 on its flow path.

[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. The calculated total ion concentration information of the raw water is sent to the control unit 110.

[0018] The casing 109 is a hollow cylindrical member, and the raw water is softened and the ion exchange resin is regenerated within the casing 109 .

[0019] 2 and 3, the hollow space of the casing 109 is provided with a water conveying section 203, a water softening chamber 209, a neutralization chamber 210, and a water conveying section 204, in this order from the side closest to a central axis I connecting the top and bottom surfaces of the casing 109 toward the outer periphery. A water conveying section inlet 207 is provided at the center of the bottom surface of the 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 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 conveying section 203, the water softening chamber 209, the neutralization chamber 210, and the water conveying section 204. The central axis I is perpendicular to the bottom surface of the water softening chamber 209.

[0020] The water conveying section inlet 207 is provided on the bottom surface of the casing 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 casing 109. The water conveying section inlet 207 is connected in communication with the raw water supply pipe 104.

[0021] 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 can be a tube such as a pipe having an internal space.

[0022] 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 casing 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 casing 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.

[0023] 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.

[0024] 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 its inner surface side of its cylindrical shape, contacts an inner circumferential diaphragm 215, which is a cylindrical membrane that is water permeable, on its outer surface side, and contacts 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.

[0025] 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.

[0026] 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 in the water softening chamber 209. Here, "surrounded" refers to a state in which 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 around the entire circumference. However, the weakly acidic cation exchange resin 213 is usually spherical, and a water passage for the raw water must be secured. For this reason, the weakly acidic cation exchange resin 213 does not necessarily contact the surface of the first electrode 201 without any gaps, and a state in which the weakly acidic cation exchange resin 213 is arranged around the entire circumference with partial contact also falls under the term "the first electrode 201 is surrounded by the weakly acidic cation exchange resin 213."

[0027] 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.

[0028] 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. 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.

[0029] 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.

[0030] The second electrode 202 is not energized during the water softening process, and acts 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" means that the entire surface of the second electrode 202 is surrounded by the weakly basic anion exchange resin 214 from the top to the bottom. This shows a state in which the weakly basic anion exchange resin 214 is in contact with the surface of the ion exchange resin 214. However, like the weakly acidic cation exchange resin 213, the weakly basic anion exchange resin 214 usually has a spherical shape, and it is necessary to ensure a water passage for the raw water (strictly speaking, acidic soft water). For this reason, the weakly basic anion exchange resin 214 does not necessarily contact the surface of the second electrode 202 without any gaps, and a state in which the weakly basic anion exchange resin 214 is arranged around the entire circumference in a state of partial contact also falls under the term "second electrode 202 is surrounded by the weakly basic anion exchange resin 214."

[0031] 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. Multiple second electrodes 202 are provided in the neutralization chamber 210, with the distance between adjacent second electrodes 202 being equal. The second electrode 202 can be made of 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 in which a precious metal wire is wrapped 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.

[0032] The arrangement of the first electrode 201 and the second electrode 202 will be described in detail later.

[0033] 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.

[0034] 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.

[0035] 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 .

[0036] 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.

[0037] 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 casing 109. The water supply unit 204 is provided with an air vent valve 205 that vents air from inside the casing 109. The water supply unit 204 includes a side space 204a and an upper space 204b.

[0038] The side space 204a is provided on the outer peripheral side of the neutralization chamber 210 with respect to the central axis I of the casing 109. The side space 204a is a cylindrical space surrounded by the outer periphery of the diaphragm 216 and surrounding the neutralization chamber 210. The inner surface of the side space 204a contacts the outer surface of the outer periphery of the diaphragm 216, and the outer surface contacts the inner surface of the casing 109. 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 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.

[0039] The upper space 204b is a cylindrical space provided above the top surfaces of the water conveying section 203, the water softening chamber 209, the inner periphery diaphragm 215, the neutralization chamber 210, and the outer periphery diaphragm 216. The cylindrical top surface of the upper space 204b contacts the inner top wall of the casing 109, and the cylindrical bottom surface contacts the outer top wall of the lid section 208. Furthermore, the outer surface of the cylindrical shape of the upper space 204b contacts the inner surface of the side space 204a.

[0040] The water conveyance section outlet 206 is provided on the top surface of the casing 109, and discharges water from the water conveyance section 204 to the outside of the water softening device 100. The central axis of the water conveyance section outlet 206 coincides with the central axis I of the casing 109. The water conveyance section outlet 206 is connected in communication with the softened water supply pipe 105. Return to FIG. 1.

[0041] The softened water supply pipe 105 is a pipe that connects the water conveyance unit outlet 206 with the destination of softened water, and is provided with a softened water conductivity measuring unit 102 and a water volume measuring unit 103 on its flow path. A drain pipe 107 branches off from the softened water supply pipe 105 midway along its flow path. A softened water supply pipe on-off valve 106 is provided on the softened water supply pipe 105 downstream of the branch point with the drain pipe 107.

[0042] 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. The calculated total ion concentration information of the soft water is sent to the control unit 110, which will be described later.

[0043] 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.

[0044] The drain pipe 107 is a pipe branched off from the soft water supply pipe 105 upstream of the soft water supply pipe on-off valve 106, and is a pipe for draining water during the regeneration process. The drain pipe is provided with a drain pipe on-off valve 108 on its flow path.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The storage unit 112 stores the information transmitted to the control unit 110 and the calculated value of the information. Each piece of information is stored.

[0049] 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 .

[0050] The positions of the first electrode 201 and the second electrode 202 will be described in more detail with reference to Fig. 4. Fig. 4 is a cross-sectional view showing the positions of the first electrode and the second electrode of the water softening device, and is a cross-sectional view taken along the AA' plane shown in Fig. 3. The AA' plane is parallel to the bottom surface of the water softening chamber 209. In other words, the plane shown in Fig. 4 is a cross section parallel to the bottom surface of the water softening chamber 209.

[0051] The water conveying 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, each has a circular cross section, and the centers of the respective circles are substantially the same (point O). The water softening chamber 209, the inner diaphragm 215, the neutralization chamber 210, and the water supply section 204 are arranged in this order toward the outer periphery of an imaginary circle X centered at point O. In this embodiment, the imaginary circle X coincides with the outer periphery of the water supply section 204. A plurality of first electrodes 201 and a plurality of second electrodes 202 are provided. Furthermore, each pair of the first electrode 201 and the second electrode 202 is provided on the same radius of the imaginary circle X. "On the same radius" refers to a radius in the same direction, and refers to, for example, line B in FIG. 4 . In this embodiment, eight pairs of electrodes are provided on the same diameter of the cylindrical casing 109.

[0052] In the water softening process, as described above, raw water flows through the water softening device 100 from the water conveying section 203 through the water softening chamber 209, the neutralization chamber 210, and the water supply section 204 in this order. That is, the raw water flows from the center (point O) of the imaginary circle X toward the outer periphery of the imaginary 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 conveying 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 periphery diaphragm 215. That is, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are consumed from the center of the cross section in FIG. 4 . Meanwhile, in the regeneration process, hydrogen ions necessary for regenerating the weakly acidic cation exchange resin 213 are produced from the first electrode 201, and hydroxide ions necessary for regenerating the weakly basic anion exchange resin 214 are produced from the second electrode 202. Therefore, by providing the first electrode 201 and the second electrode 202 at positions where the ion exchange resins are consumed, the regeneration efficiency of the ion exchange resins in the regeneration process can be improved. Here, the first boundary 401, the second boundary 402, the intermediate portion 403, and the intermediate portion 404 are defined. The first boundary 401 is the boundary between the water conveying portion 203 and the water softening chamber 209. The second boundary 402 is the boundary between the neutralization chamber 210 and the water supply portion 204. In other words, the second boundary 402 is the outer periphery diaphragm 216. The intermediate portion 403 is a substantially circular imaginary line centered at point O, and is provided equidistant from the first boundary 401 and the inner periphery diaphragm 215, and is equidistant from the first boundary 401 and the inner periphery diaphragm 215 on the same radius. The intermediate portion 404 is a substantially circular imaginary line centered at point O, and is provided equidistant from the inner diaphragm 215 and the second boundary portion 402, and is equidistant from the inner diaphragm 215 and the second boundary portion 402 on the same radius. The first electrode 201 is provided at a position biased toward the water conducting portion 203 with respect to the midpoint between the inner diaphragm 215 and the first boundary portion 401, which is the boundary between the water conducting portion 203 and the water softening chamber 209, on the same radius in the cross section of the water softening device 100. In other words, the distance between the first electrode 201 and the first boundary portion 401 is shorter than the distance between the first electrode 201 and the inner diaphragm 215 on the same radius.Furthermore, the second electrode 202 is provided at a position shifted toward the inner diaphragm 215 from the midpoint between the second boundary portion 402, which is the boundary between the neutralization chamber 210 and the water supply portion 204, and the inner diaphragm 215, on the same radius in the cross section of the water softener 100. In other words, on the same radius, the distance between the second electrode 202 and the inner diaphragm 215 is shorter than the distance between the second electrode 202 and the second boundary portion 402. By arranging in this manner, the ion exchange resins required for regeneration are directly distributed near the areas where they are most consumed. This allows the supply of necessary hydrogen ions or hydroxide ions, thereby improving the regeneration efficiency in the regeneration process. The first electrode 201 can be positioned without any particular limitation, as long as it is closer to the center than the intermediate portion 403 between the first boundary portion 401 and the inner diaphragm 215. Similarly, the second electrode 202 can be positioned without any particular limitation, as long as it is closer to the center than the intermediate portion 404 between the inner diaphragm 215 and the second boundary portion 402. However, the shorter the distance between the pair of first electrode 201 and second electrode 202, the lower the voltage applied between the first electrode 201 and the second electrode 202 and the lower the power consumption. Therefore, from the perspective of reducing power consumption, it is preferable to position the first electrode 201 and the second electrode 202 close to each other. The first electrode 201 and the second electrode 202 may be arranged so that the ratio of the distance from the water conducting section 203 to the first electrode 201 to a first distance from the first boundary section 401 to the inner diaphragm 215 is equal to the ratio of the distance from the inner diaphragm 215 to the second electrode 202 to a second distance from the inner diaphragm 215 to the second boundary section 402.

[0053] The water softening device 100 has the above configuration.

[0054] Next, the processes of the water softening device 100 (water softening process, regeneration process, cleaning process, and electrode cleaning process) will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram including formulas showing the principle of the water softening device in embodiment 1. Fig. 6 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.

[0055] 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.

[0056] 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 casing 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.

[0057] 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.

[0058] 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. Specifically, hydrogen ions in the softened water are removed from the softened water by being adsorbed onto the weakly basic anion exchange resin 214, and neutral softened water (neutralized softened water) is produced. 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.

[0059] 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.

[0060] 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.

[0061] In the water softening process, 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 weakly basic As the amount of anions adsorbed onto the anion exchange resin 214 increases, the resin's ability to soften water decreases, and a regeneration process must be performed.

[0062] 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.

[0063] As a result, a reaction that produces hydrogen ions (see formula (5) in FIG. 5) occurs at the first electrode 201, which is the anode, and a reaction that produces hydroxide ions (see formula (6) in FIG. 5) 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.

[0064] 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.

[0065] 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.

[0066] In this manner, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are regenerated in the regeneration process.

[0067] 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 .

[0068] 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 casing 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.

[0069] 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- These are anions. According to the principle of electroneutrality, 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.

[0070] 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.

[0071] Here, the current value and current application time required to remove the estimated adsorbed ions from the water softening device 100 and to regenerate the water softening device 100 will be described with reference to FIGS. 5 and 6. In the bioprocess, 1 mole of electrons is converted to 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, the current value, and the time is expressed by equation (2) in FIG.

[0072] 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 5.

[0073] 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.

[0074] 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 6, 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.

[0075] 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.

[0076] A timer 113 is used to measure the change in the applied current over time. The memory 112 stores a first reference value, which maximizes the current, and a second reference value, which starts decreasing the current from the maximum value, as reference times indicating when to change the current. The first reference value is set approximately 30 minutes to 1 hour after the start of current application. The second reference value is set later than the first reference value and 30 minutes to 1 hour before the end of current application. The current and time required for the regeneration process are determined by the adsorbed hardness, as shown in equation (1) in Figure 5. Therefore, 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.

[0077] 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.

[0078] 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.

[0079] After the regeneration process is complete, a cleaning operation must be performed inside the water softening device 100 because 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. If the cleaning is insufficient, the remaining ions may mix with the water during the water softening process, resulting in insufficient water softening. For this reason, a cleaning process is performed after the regeneration process is complete.

[0080] During the cleaning process, in the water softening device 100, the softened water supply pipe on-off valve 106 is closed and the drain pipe on-off valve 108 is opened, causing 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 raw water supply pipe 104, making it possible to restart the regeneration process.

[0081] 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 set to be longer than the residence time, which is the time from when the raw water flows into the water softening chamber 209 to when it flows out of the neutralization chamber 210. This allows the water in the water softening chamber 209 that contains a large amount of desorbed hardness ions to be discharged, and the water in the water softening chamber 209 to be replaced with raw water.

[0082] 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 off the calcium carbonate from the electrode surface occur. Therefore, it is necessary to periodically carry out an electrode cleaning process to remove calcium carbonate from the cathode surface.

[0083] 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 is carried out during or after the regeneration process is completed.

[0084] As described above, in the water softening apparatus 100, the softening of raw water by the water softening process, the regeneration process, the cleaning process, and the maintenance of the water softening apparatus 100 by the electrode cleaning process are repeatedly performed.

[0085] As described above, the water softening device 100 according to this embodiment can provide the following effects.

[0086] (1) The water softening device 100 includes a water softening chamber 209 containing a weakly acidic cation exchange resin 213 that produces soft water from raw water containing hardness components, a neutralization chamber 210 containing a weakly basic anion exchange resin 214 that neutralizes the softened 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 introduces raw water from the outside into the water softening chamber, a water conveying section 204 that conveys the neutralized softened water produced in the neutralization chamber 210 to the outside, a first electrode 201 that is surrounded by the weakly acidic cation exchange resin 213 in the water softening chamber 209 and acts as an anode during regeneration of the weakly acidic cation exchange resin 213, and a second electrode 202 that is surrounded by the weakly basic anion exchange resin 214 in the neutralization chamber 210 and acts as a cathode during regeneration of the weakly basic anion exchange resin 214. The water softening chamber 209, the inner diaphragm 215, the neutralization chamber 210, and the water conveying section 204 are arranged in this order from the water conveying section 203 having a central axis I perpendicular to the bottom surface of the water softening chamber 209 toward the outer periphery of a circle centered on the central axis I. 1 is disposed in a position biased toward the water conducting section 203 side within the water softening chamber 209. More specifically, the first electrode 201 is disposed on the water conducting section 203 side of the midpoint between the inner periphery-side diaphragm 215 and a first boundary section 401, which is the boundary between the water conducting section 203 and the water softening chamber 209, on the same radius of a circle in a cross section parallel to the bottom surface of the water softening chamber 209.

[0087] With this configuration, during the regeneration process, hydrogen ions can be generated near the weakly acidic cation exchange resin 213, which has a large amount of hardness ion adsorption, in the water softening chamber 209. This prevents the generated hydrogen ions from reacting with other ions and being lost before being used to regenerate the weakly acidic cation exchange resin 213, thereby improving the regeneration efficiency.

[0088] (2) In the water softener 100, the second electrode 202 is disposed in the neutralization chamber 210 at a position offset toward the inner diaphragm 215. More specifically, the second electrode 202 is disposed on the same radius closer to the inner diaphragm 215 than the midpoint between the inner diaphragm 215 and the second boundary 402, which is the boundary between the neutralization chamber 210 and the water supply section 204. With this configuration, during the regeneration process, hydroxide ions can be generated in the neutralization chamber 210 near the weakly basic anion exchange resin 214, which has a large ion adsorption capacity. This prevents the generated hydroxide ions from reacting with other ions and being lost before being used to regenerate the weakly basic anion exchange resin 214, thereby improving the regeneration efficiency.

[0089] (3) In the water softening device 100, the pair of first electrode 201 and second electrode 202 are provided on the same radius in a cross section parallel to the bottom surface of the water softening chamber 209, and are provided at positions where the ratio of the distance from the water conducting section 203 to the first electrode 201 to a first distance from the first boundary 401 to the inner diaphragm 215 is equal to the ratio of the distance from the inner diaphragm 215 to the second electrode 202 to a second distance from the inner diaphragm 215 to the second boundary 402. With this configuration, the first electrode 201 and the second electrode 202 are both provided at similar positions from the center in each chamber.

[0090] The present invention has been described above based on the embodiments. These embodiments are excitation, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each process, and that such modifications are also within the scope of the present invention.

[0091] In the first embodiment, the first electrode 201 is offset toward the center of the circle from the midpoint between the first boundary 401 and the inner diaphragm 215, and the second electrode 202 is offset toward the center of the circle from the midpoint between the inner diaphragm 215 and the second boundary 402. However, the present invention is not limited to this. For example, only the first electrode 201 may be offset toward the center from the midpoint between the first boundary 401 and the inner diaphragm 215. [Industrial Applicability]

[0092] The water softening device of the present invention can reduce the frequency of drainage or even eliminate the need for drainage altogether, thereby reducing the amount of drainage, and as a secondary effect, can also shorten the regeneration time and increase the electrode life, making it useful as a water softening device, etc. [Explanation of symbols]

[0093] 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 Casing 110 control section 111 Adsorption amount estimator 112 Storage section 113 Timing section 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 401 First boundary 402 Second boundary 403 Middle section 404 Middle section

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 having a weakly basic anion exchange resin for neutralizing 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 that introduces the raw water from the outside into the water softening chamber; a water supply unit that supplies the neutralized soft water produced in the neutralization chamber to the outside; a first electrode that is disposed in the water softening chamber and is 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 acts as a cathode during regeneration of the weakly basic anion exchange resin; Equipped with The water softening chamber, the diaphragm, the neutralization chamber, and the water supply unit are arranged in this order from the water conveying unit having a central axis perpendicular to the bottom surface of the water softening chamber toward the outer periphery of a circle centered on the central axis, The first electrode is disposed in the water softening chamber at a position biased toward the water conveying section.

2. The water softening device according to claim 1 , wherein the second electrode is disposed in the neutralization chamber at a position offset toward the diaphragm.

3. The first electrode is The water softening device according to claim 1, wherein the diaphragm is positioned closer to the water conveying section than the midpoint between the diaphragm and a first boundary section, which is a boundary between the water conveying section and the water softening chamber, on the same radius of the circle in a cross section parallel to the bottom surface of the water softening chamber.

4. The second electrode is The water softening device according to claim 3, wherein the second boundary portion is disposed on the same radius on the diaphragm side of a midpoint between the diaphragm and a second boundary portion which is a boundary between the neutralization chamber and the water conveying portion.

5. The pair of the first electrode and the second electrode is In the cross section, the grooves are provided on the same radius, a ratio of a distance from the water guide portion to the first electrode to a first distance from the first boundary portion to the diaphragm; The water softening device according to claim 4 , wherein the second electrode is provided at a position where a ratio of a distance from the diaphragm to the second electrode is equal to a second distance from the diaphragm to the second boundary portion.

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