Water softener

Abstract

To provide a water softener capable of suppressing wastewater discharge during regeneration and efficiently regenerating resin.SOLUTION: A water softener includes a water softening chamber 209, a neutralization chamber 210, a diaphragm, a first electrode 201 surrounded with a weakly acidic cation exchange resin 213 in the water softening chamber 209, a second electrode 202 surrounded with a weakly basic anion exchange resin 214 in the neutralization chamber 210, and a control unit 110. The control unit 110 executes a water softening process in which water to be treated is made to pass through a lower part of the water softening chamber 209, the water softening chamber 209, and the neutralization chamber 210 in this order to obtain soft water, a regeneration process in which ion exchange resin is regenerated, a cleaning process to remove cations and anions released by the regeneration process from the water softening chamber 209 and the neutralization chamber 210, and an electrode cleaning process for dissolving solids that have adhered to a surface of the second electrode 202 in the regeneration process during or after the regeneration process.SELECTED DRAWING: Figure 1

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, to solve the issues of the workload involved in replenishing salt and the performance issue of not being able to obtain soft water if salt replenishing is not carried out appropriately, a water softening technology has been developed that allows maintenance to be performed without using salt (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 both of the conventional technologies, the resin needs to be regenerated once a certain amount of hardness ions are adsorbed onto the resin. For example, in the regeneration process 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] Patent No. 6444939 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 the problem of increasing the amount of wastewater discharged during resin regeneration.

[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 softened water, a diaphragm that separates the water softening chamber from the neutralization chamber and allows soft water to pass through, a first electrode that acts as an anode during regeneration of the weakly acidic cation exchange resin, and a second electrode that acts as a cathode during regeneration of the weakly basic anion exchange resin. The first electrode is provided in the water softening chamber surrounded by the weakly acidic cation exchange resin, and the second electrode is provided in the neutralization chamber surrounded by the weakly basic anion exchange resin. The device also comprises a control unit that controls the regeneration of the weakly acidic cation exchange resin and the weakly basic anion exchange resin. The control unit supplies water to be treated from the bottom of the water softening chamber. The system performs the following steps: a water softening process in which water is introduced into the water softening chamber and then passed through the neutralization chamber to obtain soft water; a regeneration process in which current is passed through the first and second electrodes to generate hydrogen ions from the first electrode by water electrolysis, generate hydroxide ions from the second electrode, and use the generated hydrogen ions to regenerate the weakly acidic cation exchange resin and the weakly basic anion exchange resin to regenerate the weakly basic anion exchange resin; a cleaning process in which cations released from the weakly acidic cation exchange resin during the regeneration process are discharged from the water softening chamber and anions released from the weakly basic anion exchange resin during the regeneration process are discharged from the neutralization chamber; and an electrode cleaning process in which the first electrode is connected to the negative electrode and the second electrode is connected to the positive electrode during or after the regeneration process, and solids attached to the surface of the second electrode during the regeneration process are dissolved. [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] 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] Schematic diagram of a water softening device according to a third embodiment [Figure 7] Schematic diagram of a water softening device according to a fourth embodiment [Figure 8] Schematic diagram of a water softening device according to a fifth embodiment [Figure 9] Schematic diagram of a water softening device according to a sixth 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 do not limit the technical scope of the present invention. Furthermore, each drawing described 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 the water conveyance section inlet 207, and is provided with the raw water conductivity measuring section 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. 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 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, 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 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 central axis I. A water conveying section outlet 206 is provided at the center of the top surface of casing 109, i.e., on 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.

[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.

[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 disposed within the casing 109 and is spaced apart from the central axis I of the casing 109. The water softening chamber 209 is a cylindrical space (first space 211) provided on the outer periphery of the water conducting part 203 and containing weakly acidic cation exchange resin 213. The central axis of the water softening chamber 209 coincides with the central axis I of the casing 109. The water softening chamber 209 is in contact with the water conducting part 203 on the inner surface side of its cylindrical shape, in contact with an inner periphery diaphragm 215 which is a cylindrical membrane having water permeability on the outer surface side, and in contact with the lid part 208 on the top surface. A first electrode 201 is provided in the water softening chamber 209.

[0025] 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."

[0026] 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 neutralization chamber 210 is in contact with the outer surface of the inner circumferential diaphragm 215 on the inner surface side of its cylindrical shape, in contact with the inner surface of the outer circumferential diaphragm 216, which is a cylindrical membrane that is water permeable, on the outer surface side of its cylindrical shape, and in contact with the lid 208 on the upper surface. A second electrode 202 is provided in the neutralization chamber 210.

[0027] 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."

[0028] 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.

[0029] The water supply unit 204 supplies the soft 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.

[0030] The water conveyance unit outlet 206 is provided on the top surface of the casing 109, and discharges the water in the water conveyance unit 204 to the outside of the water softening device 100. The central axis of the water conveyance unit outlet 206 coincides with the central axis I of the casing 109. Return to FIG.

[0031] The soft water supply pipe 105 is a pipe that connects the water supply outlet 206 with the destination of the soft water supply, and is provided with a soft water conductivity measuring unit 102 and a water volume measuring unit 103 on its flow path. A drain pipe 107 branches off from the soft water supply pipe 105 midway along its flow path. A soft water supply pipe on-off valve 106 is provided on the soft water supply pipe 105 on the downstream side.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 .

[0039] 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 .

[0040] The water softening device 100 has the above configuration.

[0041] Next, the processes of the water softening device 100 (water softening process, regeneration process, cleaning process, and electrode cleaning process) will be described.

[0042] 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.

[0043] In the water softening device 100, raw water flows from the outside into the lower part of the water conveying part 203 through the water conveying part inlet 207. The flowing raw water is sent from the lower part to the upper part of the water conveying part 203 and flows out in the radial direction of the casing 109 from holes provided in the side wall of the water conveying part 203. In other words, the raw water is sent out from the holes in the water conveying part 203 to the water softening chamber 209.

[0044] 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 softened by the weakly acidic cation exchange resin 213 and the hydrogen ions adsorbed on the weakly acidic cation exchange resin 213. The water is exchanged and becomes acidic soft water containing hydrogen ions.

[0045] 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 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.

[0046] The neutral 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.

[0047] 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.

[0048] In the water softening process, if the amount of hardness 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.

[0049] In the regeneration process, raw water first flows from the raw water supply source into the water conveying section 203 via the water conveying section inlet 207, and is then 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.

[0050] As a result, a reaction that produces hydrogen ions (see formula 5 in FIG. 3) occurs at the first electrode 201, which is the anode, and a reaction that produces hydroxide ions (see formula 6 in FIG. 3) 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.

[0051] 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.

[0052] 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.

[0053] In this manner, the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214 are regenerated in the regeneration process.

[0054] 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 .

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 moles of adsorbed ions estimated by the adsorption amount estimation unit 111 and Equation 2.

[0060] 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.

[0061] 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 in a concentration greater than the capacity of the resin are input to the weak acidic cation exchange resin 213 or the weak basic anion exchange resin 214, the hydrogen ions or hydroxide ions will react with each other without reacting with the ions in the resin, resulting in a loss.

[0062] 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.

[0063] A timer 113 is used to measure the change in the applied current over time. The memory 112 stores a first reference value at which the current reaches its maximum value and a second reference value at which the current starts decreasing from its 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. Since the current and time required for the regeneration process are determined by the adsorbed hardness as shown in equation (1), extending 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 requires an increase in the maximum current value or regeneration time.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] During the regeneration process, solid calcium carbonate and other substances 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. For this reason, it is necessary to periodically carry out an electrode cleaning process to remove calcium carbonate from the cathode surface.

[0070] 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.

[0071] As described above, the water softening device 100 softens and recycles raw water through the water softening process. The water softening device 100 is repeatedly maintained through the raw process, cleaning process, and electrode cleaning process.

[0072] (Embodiment 2) The water softening device 100b according to the second embodiment of the present invention differs from the first embodiment in that an electrolyte other than hydrogen ions and hydroxide ions is introduced into the water softening chamber and the neutralization chamber during the regeneration process. The rest of the configuration is the same as that of the water softening device 100 according to the first embodiment. Below, the content already explained in the first embodiment will be omitted as appropriate, and the differences from the first embodiment will be mainly explained.

[0073] If the electrolyte concentration of the water in the water softener 100b is low during the regeneration process, particularly at the start of energization, the voltage when energizing the first electrode 201 and the second electrode 202 will be high, resulting in issues such as an inability to apply a predetermined current or increased power consumption. Therefore, in this embodiment, electrolytes are supplied to reduce the water resistance during electrolysis in the regeneration process. Specifically, raw water is supplied to utilize the electrolytes in the raw water. The water softener 100b is primarily used in hard water regions. Since raw water in hard water regions contains many ions, including hardness ions, at high concentrations, supplying raw water allows the ions in the raw water before softening to be used as electrolytes at the start of the regeneration process.

[0074] A method for supplying electrolytes in a regeneration process using raw water will be described.

[0075] Before energizing the first electrode 201 and the second electrode 202 in the regeneration process, the water softener 100b is filled with raw water. Specifically, after closing the soft water supply pipe valve 106, the drain pipe valve 108 is opened, and raw water is supplied to the water softener 100b by tap water pressure. That is, the water softener 100b includes a raw water supply pipe 104 as an electrolyte supply unit. After a certain time has elapsed since the start of supply, the drain pipe valve 108 is closed to terminate drainage. Thereafter, energization of the first electrode 201 and the second electrode 202 is initiated. Note that if a long time elapses between the introduction of raw water into the water softener 100b and the start of energization, ions in the raw water will be adsorbed by the weakly acidic cation exchange resin 213 or the weakly basic anion exchange resin 214. Therefore, it is preferable to start energization as soon as possible after closing the drain pipe valve 108. The time for which the drain pipe on-off valve 108 is kept open is preferably at least the time required for the water in the water softening device 100b to be replaced, and if tap water is used for domestic use, it will suffice to keep the valve open for a few minutes.

[0076] (Embodiment 3) The water softening apparatus 100c according to the third embodiment of the present invention differs from the second embodiment in that it includes a chemical sustained-release unit 302 as an electrolyte input unit that inputs electrolytes other than hydrogen ions and hydroxide ions as chemicals to the raw water passing through the water softening chamber 209 and the neutralization chamber 210 during the regeneration process. The rest of the configuration is the same as that of the water softening apparatus 100b according to the second embodiment. Below, the content already explained in the second embodiment will be omitted as appropriate, and the differences from the second embodiment will be mainly explained.

[0077] A water softening device 100c according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a conceptual diagram showing the configuration of the water softening device 100c according to this embodiment. Note that Fig. 6 conceptually shows each element of the water softening device 100c.

[0078] The raw water supply pipe 104 is a pipe that connects a source of raw water, such as a water supply, to the water conveyance inlet 207, and the chemical addition pipe 301 branches off at a branch point provided midway along the flow path, and the chemical addition pipe 301 reconnects at a junction point downstream of the branch point. The soft water supply pipe 105 is equipped with a soft water supply pipe on-off valve 106 downstream of the branch point with the drainage pipe 107. The raw water supply pipe 104 is equipped with the raw water supply pipe on-off valve 304 downstream of the branch point with the chemical addition pipe 301 and upstream of the junction point. Prepare.

[0079] The chemical addition pipe 301 is a pipe that bypasses the raw water supply pipe 104 from its branch point to its junction point, and is provided with a chemical addition pipe opening / closing valve 303 and a chemical sustained release section 302 on the flow path.

[0080] The chemical release unit 302 is located downstream of the chemical addition pipe on-off valve 303 and adds a chemical to the raw water that has flowed into the chemical addition pipe 301. This supplies electrolytes to the raw water. Any chemical that is harmless to the human body can be used as the chemical to be added; specifically, food-grade chemicals are preferred. Examples include sodium sulfate, sodium chloride, calcium chloride, and sodium polyphosphate. The polarity is not particularly limited, but since the water is used for daily life, neutral salts that result in a neutral pH are preferred. Among neutral salts, sulfates and phosphates, which have little impact on the anode life, are more preferred.

[0081] Raw water supply pipe on-off valve 304 is a valve that is provided on raw water supply pipe 104 and has an adjustable opening. By opening or closing the valve or adjusting the opening, the electrolyte concentration in the raw water can be adjusted. If it is desired to increase the electrolyte concentration in the raw water, raw water supply pipe on-off valve 304 is closed when chemical addition pipe on-off valve 303 is opened. As a result, all raw water flowing into casing 109 passes through chemical slow-release section 302, resulting in water containing a higher concentration of electrolytes than the original raw water. On the other hand, if it is desired to decrease the electrolyte concentration in the raw water, raw water supply pipe on-off valve 304 is also opened when chemical addition pipe on-off valve 303 is opened. As a result, only a portion of the raw water flowing into casing 109 passes through chemical slow-release section 302, while the remaining raw water does not pass through chemical slow-release section 302, resulting in water with a higher electrolyte concentration than raw water but a lower electrolyte concentration than when raw water supply pipe on-off valve 304 is closed.

[0082] The flow path configuration during the water softening process and the flow path configuration during the regeneration process in the third embodiment will be described.

[0083] In the water softening process, raw water is introduced into the water softening device 100c with the raw water supply pipe on-off valve 304 and the soft water supply pipe on-off valve 106 open and the chemical addition pipe on-off valve 303 and the drain pipe on-off valve 108 closed. This allows the raw water to be softened in the same way as in the first embodiment.

[0084] In the regeneration process, before supplying raw water, the softened water supply pipe valve 106 is closed, and the drain pipe valve 108 and chemical addition pipe valve 303 are opened. To prevent chemicals from entering the softened water supply pipe 105, it is preferable to close the softened water supply pipe valve 106 before opening the drain pipe valve 108 and chemical addition pipe valve 303. By supplying raw water in this state, the chemical addition pipe valve 303 is open, and the chemical is released from the chemical release unit 302 into the raw water. The chemical dissolves in the raw water, producing electrolyte-containing water with a high electrolyte concentration. With this electrolyte-containing water filling the water softening device 100c, electrolysis is performed by the first electrode 201 and the second electrode 202, and the regeneration of the ion exchange resin progresses. After a certain time has elapsed since the start of electrolysis, the drain pipe valve 108 and chemical addition pipe valve 303 are closed. To reduce the water pressure on the water softening device 100c, it is better to close the chemical addition pipe on-off valve 303 first and then close the drain pipe on-off valve 108. The time during which the electrolyte-containing water flows through the water softening device 100c, that is, the time during which the drain pipe on-off valve 108 is kept open, should be at least the time it takes for the water in the water softening device 100c to be replaced, and if tap water is used for domestic use, a few minutes will suffice.

[0085] (Fourth embodiment) The water softening apparatus 100d according to the fourth embodiment of the present invention is different from the second embodiment in that it uses wastewater discharged after the previous regeneration process as an electrolyte when the current starts to flow in the regeneration process. The rest of the configuration is the same as that of the water softening device 100b according to embodiment 2. Hereinafter, the content already explained in embodiment 2 will be omitted as appropriate, and differences from embodiment 2 will be mainly explained.

[0086] A water softening device 100d according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a conceptual diagram showing the configuration of the water softening device 100d according to this embodiment. Note that Fig. 7 conceptually shows each element of the water softening device 100d.

[0087] The raw water supply pipe 104b is a pipe that connects a source of raw water, such as a water supply, to the water conveyance section inlet 207, and is connected to the reclaimed water return pipe 405 (described later) at a junction provided midway along the flow path.

[0088] The soft water supply pipe 105a is a pipe that connects the water conveyance unit outlet 206 and the supply destination of the soft water, and a drain pipe 107a branches off midway along the flow path. A soft water supply pipe opening / closing valve 106 is provided downstream of the branch point of the drain pipe 107a.

[0089] The drain pipe 107a is a pipe that branches off from the soft water supply pipe 105a upstream of the soft water supply pipe on-off valve 106, and is a pipe that drains water during the regeneration process. The drain pipe 107a is provided with a drain pipe on-off valve 108 on its flow path, and is connected to the soft water supply pipe 105a at one end and to the storage chamber 401 at the other end.

[0090] The storage chamber 401 is a tank that stores the cleaning water drained from the water softening chamber 209 and the neutralization chamber 210 during the cleaning process described below, and is equipped with an inlet 402, a first water supply port 403, and a second water supply port 404.

[0091] Inlet 402 is an opening for introducing water into reservoir 401, and is connected to drain pipe 107a. Inlet 402 is preferably provided in an upper portion of reservoir 401.

[0092] The first water supply port 403 is an opening for discharging the water in the storage chamber 401 to the outside of the water softening device 100d, and is connected to the drain pipe 107 through which drainage water flows. The first water supply port 403 is preferably provided in the upper part of the storage chamber 401.

[0093] The second water supply port 404 is connected to a reclaimed water return pipe 405 described later, and is an opening for sending the water in the storage chamber 401 to the reclaimed water return pipe 405.

[0094] The reclaimed water return pipe 405 is a pipe having one end connected to the second water supply port 404 and the other end connected to the raw water supply pipe 104b, and supplies the wastewater in the storage chamber 401 to the raw water supply pipe 104b. The reclaimed water return pipe 405 is provided with a reclaimed water return pipe opening / closing valve 406 midway along its flow path.

[0095] That is, the water softening device 100d includes a storage chamber 401 as an electrolyte supply unit.

[0096] The flow path configuration during the water softening process and the flow path configuration during the regeneration process in the fourth embodiment will be described.

[0097] In the water softening process, the softened water supply pipe on-off valve 106 is opened, and the drain pipe on-off valve 108 and the reclaimed water return pipe on-off valve 406 are closed, and raw water is introduced into the water softening device 100d. In this way, the raw water is softened in the same manner as in the first embodiment.

[0098] In the regeneration process, before supplying raw water, the soft water supply pipe on-off valve 106 is closed, and the drain pipe on-off valve 108 and the reclaimed water return pipe on-off valve 406 are opened. By this opening and closing operation, part of the raw water introduced from the raw water supply pipe 104 is discharged from the first water supply port 403 of the storage chamber 401. The remaining raw water flows out of the water softening device 100d, and passes through the storage chamber 401, passes through the second water supply port 404, passes through the reclaimed water return pipe 405, and is supplied back into the casing 109. With this configuration, water in the storage chamber 401 can be supplied by utilizing water line pressure, so there is no need to provide a pump.

[0099] The wastewater discharged after the regeneration process contains a large amount of ions released during the process, so by utilizing this wastewater and supplying it to raw water, the electrolyte concentration in the raw water can be increased.The ions released from the resin during the regeneration process are ions that were originally contained in the raw water, so they can be used without any problems from a safety standpoint.

[0100] The timing for storing the wastewater containing electrolyte in the storage chamber 401 is during the cleaning process that is carried out after the regeneration process.

[0101] The cleaning process is a process in which cations released from the weakly acidic cation exchange resin 213 by the regeneration process are discharged from the water softening chamber 209, and anions released from the weakly basic anion exchange resin 214 are discharged from the neutralization chamber 210.

[0102] At the beginning of the cleaning process, water containing a high concentration of ions released from the resin is discharged from casing 109, but as the cleaning progresses, the ion concentration in the wastewater decreases and becomes close to that of the raw water. Therefore, from the perspective of increasing the electrolyte concentration when current is applied to first electrode 201 and second electrode 202, it is preferable to retain as much water as possible at the beginning of the cleaning process in storage chamber 401. By providing inlet 402 and first water outlet 403 at the top, the structure makes it easy for water to stagnate in storage chamber 401, making it easier to retain water at the bottom of storage chamber 401 at the beginning of the cleaning process.

[0103] (Embodiment 5) A water softening device 100e according to embodiment 5 of the present invention differs from embodiment 1 in that it includes a plurality of water softening modules. Other configurations are the same as those of the water softening device 100 according to embodiment 1. Below, the following will mainly describe the differences from embodiment 1, omitting repeated explanations of the contents already explained in embodiment 1.

[0104] A water softening device 100e according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a conceptual diagram showing the configuration of the water softening device 100e according to this embodiment. Note that Fig. 8 conceptually shows each element of the water softening device 100e.

[0105] The water softening device 100e includes a plurality of water softening modules, and in this embodiment includes two water softening modules 501 (a water softening module 501a and a water softening module 501b).

[0106] The water softening module 501 includes the casing 109 and the configuration inside the casing 109 in the first embodiment, and specifically includes at least a water softening chamber, a neutralization chamber, and a diaphragm.

[0107] The water softening module 501a provided on the upstream side and the water softening module 501b provided on the downstream side are connected by a piping connecting pipe 502. Specifically, the water conveying section inlet 207 of the water softening module 501a is connected to the raw water supply pipe 104, and the water conveying section outlet 206 is connected to the connecting pipe 502. Furthermore, the water conveying section inlet 207 of the water softening module 501b is connected to the connecting pipe 502, and the water conveying section outlet 206 is connected to the softened water supply pipe 105.

[0108] The raw water supply pipe 104 is provided with a conductivity meter 503a, the connection pipe 502 is provided with a conductivity meter 503b, and the softened water supply pipe 105 is provided with a conductivity meter 503c.

[0109] The conductivity meter 503 a measures the conductivity of the water flowing through the raw water supply pipe 104 , that is, the water flowing into the water softening module 501 .

[0110] The conductivity meter 503b measures the conductivity of the water flowing through the connecting pipe 502, that is, the water flowing out from the water softening module 501a.

[0111] The conductivity meter 503c measures the conductivity of the water flowing through the softened water supply pipe 105, that is, the water flowing out from the water softening module 501b.

[0112] When connecting water softening modules in multiple stages, the ion adsorption capacity of each module often does not match. For example, when two water softening modules are connected, raw water flows into the first module, while water whose hardness has been reduced by the previous softening process flows into the second module. From equation (1) shown in Figure 4, as the water hardness decreases, the hardness adsorption reaction rate slows, resulting in a decrease in the amount of hardness adsorbed into the water softening chamber 209. The amount of adsorption into the neutralization chamber 210 also decreases. Therefore, when comparing the ion adsorption capacity of each water softening module, the amount of adsorption into the first module is greater than the amount of adsorption into the second module. Therefore, it is desirable to set the current value or current application time according to the degree of resin wear in each water softening module, which also leads to reduced power consumption. Therefore, the water softening device 100e calculates the optimal current value and current application time for each water softening module during the regeneration process.

[0113] During the regeneration process, conductivity meters 503a, 503b, and 503c measure the conductivity of the water flowing through each flow path, and calculate the difference in conductivity before and after each water softening module. Water volume measurement unit 103 also measures the cumulative amount of water passing through the water softening module. The current value and duration required to regenerate the water softening chamber and neutralization chamber of each water softening module are calculated from the resulting difference in conductivity and the cumulative amount of water passing.

[0114] (Embodiment 6) The water softening apparatus 100f according to the sixth embodiment of the present invention differs from the first embodiment in that a drainage process is executed to drain the water from the apparatus during the regeneration process in order to reduce the ion concentration of the water in the water softening apparatus 100f. Other configurations are the same as those of the water softening apparatus 100 according to the first embodiment. Below, the content already explained in the first embodiment will not be explained again as appropriate, and differences from the first embodiment will be mainly explained.

[0115] A water softening device 100f according to this embodiment will be described with reference to Fig. 9. Fig. 9 is a conceptual diagram showing the configuration of the water softening device 100f according to this embodiment. Note that Fig. 9 conceptually shows each element of the water softening device 100f.

[0116] The water softening device 100f includes an upstream drain pipe 601.

[0117] The upstream drain pipe 601 is a pipe branching off from the raw water supply pipe 104, and is a pipe for draining water from the water softening apparatus 100f in the drainage process. The upstream drain pipe 601 is provided with a drain valve 602.

[0118] The drain valve 602 is a valve provided on the upstream drain pipe 601, and when the drain valve 602 is opened, the water in the water softening device 100f is drained from the upstream drain pipe 601 to the outside of the water softening device 100f.

[0119] A drainage water volume measuring unit 603 is provided on the drainage pipe 107. The drainage water volume measuring unit 603 measures the amount of drainage water. The amount of water flowing into the pipe 107 is measured.

[0120] During the regeneration process, the water softening apparatus 100f executes a drainage process for draining the water in the water softening apparatus 100f in order to reduce the ion concentration of the water in the water softening apparatus 100f. The reason for this will be explained below.

[0121] In the regeneration process, as the time for which current is applied to the first electrode 201 and the second electrode 202 increases, the amount of Ca in the regenerated water increases. 2+ , Mg 2+ Concentration of cations such as ions, Cl - , SO4 2- The concentration of these ions increases. As the concentration of these ions increases, the Ca 2+ , Cl - The concentration of ions increases, and the rate of the reaction in the opposite direction to the reaction that regenerates the ion exchange resins increases. As a result, the ions desorbed from each ion exchange resin inhibit the regeneration reaction of the weakly acidic cation exchange resin 213 and the weakly basic anion exchange resin 214. In the configuration of the present invention, the regeneration reaction proceeds even without draining the water, but the efficiency of the regeneration reaction can be improved by draining the water to reduce the concentration.

[0122] The timing of draining in the draining process is determined by the timing unit 113. Specifically, when the time elapsed since the start of the regeneration process measured by the timing unit 113 exceeds a certain time, the control unit 110 opens the drain valve 602 and drains the water with an increased ion concentration present in the water softening device 100f to the outside via the upstream drain pipe 601. This reduces the ion concentration of the water in the water softening device 100f, improving the regeneration efficiency in the regeneration process.

[0123] When determining the timing of drainage based on the elapsed time from the start of the regeneration process, it is better to drain the water more frequently from the start to the middle of the regeneration process and less frequently in the latter half of the regeneration process. As shown in Figure 5, the reaction efficiency is high up to the middle of the regeneration process, so the time change in the desorbed ion concentration is large. On the other hand, the reaction efficiency is low in the latter half of the regeneration process, so the time change in the desorbed ion concentration is small. Therefore, the drainage frequency 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 in the amount of drainage and the reduction of reaction inhibition caused by desorbed ions, the drainage interval is preferably about 30 minutes. For example, the drainage process is performed once every 20 minutes until the middle of the regeneration process and once every 40 minutes in the latter half of the regeneration process.

[0124] When drainage is complete, the control unit 110 closes the drain valve 602, and after closing the drain valve 602, opens the drain pipe on-off valve 108. This allows raw water to flow in from outside the water softening device 100f, filling the water softening device 100f with raw water and making it possible to carry out the regeneration process again. The timing to end the inflow of raw water is determined by the drainage water volume measurement unit 603. Specifically, the inflow is ended when the amount of inflow water since the start of the drainage process, measured by the drainage water volume measurement unit 603, becomes greater than the combined volume of the water softening chamber 209 and the neutralization chamber 210.

[0125] 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.

[0126] In the first embodiment, the water volume measuring unit 103 is provided on the softened water supply pipe 105, but this is not limitative. For example, even if the water volume measuring unit 103 is provided midway along the piping of the raw water supply pipe 104, the volume of water passed through the water softening device 100 can be measured.

[0127] In the first embodiment, the amount of ions adsorbed in the water softening device 100 is specified by the adsorption amount estimation unit by calculating the concentration of ions adsorbed in the water softening device 100 from the difference in conductivity measured by the raw water conductivity measurement unit 101 and the soft water conductivity measurement unit 102, and then calculating the reduced ion concentration by measuring the water volume measurement unit 103. In the present embodiment, the method of multiplying the raw water ion concentration by the total amount of water passing measured by the raw water conductivity measuring unit 101 is used, but this is not limited to this. For example, a method of calculating the ion concentration in the raw water from the conductivity measured by the raw water conductivity measuring unit 101 and multiplying the calculated raw water ion concentration by the total amount of water passing measured by the water volume measuring unit 103 may be used. This calculation method makes it possible to identify the amount of adsorbed ions corresponding to changes in the quality of raw water without providing the softened water conductivity measuring unit 102. Alternatively, a method of multiplying the total amount of water passing measured by the water volume measuring unit 103 by the ion concentration measured in advance may be used. This calculation method makes it possible to identify the amount of adsorbed ions adsorbed in the water softening device 100 without providing the raw water conductivity measuring unit 101 and the softened water conductivity measuring unit 102.

[0128] In the first embodiment, the applied current value is controlled based on the elapsed time measured by the timer unit 113 from the start of energization. However, this is not limiting. For example, the applied current value may be controlled using a voltage measurement unit that measures the voltage and the amount of change in voltage over time when energization is performed on the first electrode 201 and the second electrode 202. When the voltage measurement unit changes the current value, it measures the amount of change in voltage over time and then changes the current. At the start of energization, a current lower than the target current value determined by the adsorption amount estimation unit 111 is applied, and the current is increased when the amount of change in voltage over time becomes small. This step of further increasing the current when the amount of change in voltage over time becomes small is repeated. It is preferable to increase the current in approximately 10 steps. This is because, although it depends on the amount of increase in the current value, the voltage becomes constant in approximately 5 minutes from the time the current value is increased.

[0129] In the first embodiment, the timing to end the cleaning process is determined based on time, but this is not limiting. For example, the timing can be determined by the wastewater volume measurement unit 603 installed in the drain pipe 107. The drain process can be terminated when the volume of water measured by the wastewater volume measurement unit 603 from the start of the drain process is equal to or greater than the volume of the water softening chamber 209 and the neutralization chamber 210. The timing to end the cleaning process can also be determined by the wastewater conductivity measurement unit installed in the drain pipe 107. The wastewater conductivity measurement unit measures the conductivity of the wastewater flowing out of the water softening device 100 during the cleaning process. Because the cleaning process is performed using raw water, if the desorbed ions in the water softening device 100 can be discharged outside the water softening device 100, the hardness of the drained water will be equal to or less than the hardness of the raw water. The wastewater conductivity measurement unit measures the conductivity of the wastewater and compares it with the conductivity measured by the raw water conductivity measurement unit 101. The cleaning process can be terminated when the conductivity of the wastewater is equal to or less than the conductivity of the raw water.

[0130] In the sixth embodiment, the timing of draining water is determined based on the elapsed time since the start of the regeneration process measured by the timer 113, but this is not limiting. For example, the timing of draining water may be determined using a reclaimed water conductivity measuring unit that measures the conductivity of the water in the water softening apparatus 100f and the amount of change in conductivity over time. In this case, when the conductivity of the reclaimed water conductivity measuring unit exceeds a certain value, the control unit 110 controls the opening and closing of the drain pipe opening / closing valve 108 or the drain valve 602 to drain water from the water softening apparatus 100f.

[0131] When the timing of drainage is determined by the conductivity measurement unit, the drainage pipe on-off valve on the drainage pipe 107 is opened when the conductivity exceeds a certain value, and closed after a predetermined time has passed. The location where conductivity is measured is the water conveying section, where hardness ions tend to accumulate. This is because hardness ions desorbed from the weakly acidic cation exchange resin 213 by regeneration diffuse into the water conveying section and tend to accumulate in the water conveying section, and regeneration of the weakly acidic cation exchange resin 213 is more likely to be inhibited by desorbed ions than that of the weakly basic anion exchange resin 214.

[0132] Although there are no particular restrictions on the fixed value of conductivity that serves as the standard for performing drainage, it is desirable that it be around 3 mS / cm. When the conductivity of the water in the water conveying section reaches 3 mS / cm in the regeneration process, the hardness has increased to approximately 1000 mg / L. Even if the hardness is higher than 1000 mg / L, the regeneration of the weakly acidic cation exchange resin 213 will proceed, but the efficiency will decrease due to the influence of the reverse reaction. Therefore, if drainage is performed when the conductivity reaches around 3 mS / cm, the effect of preventing the reverse reaction can be more effectively achieved. Cut. [Industrial Applicability]

[0133] 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]

[0134] 100, 100b, 100c, 100d, 100e, 100f water softener 101 Raw water conductivity measurement unit 102 Soft water conductivity measurement section 103 Water measurement section 104, 104b Raw water supply pipe 105, 105a Soft water supply pipe 106 Soft water supply pipe on-off valve 107, 107a Drainage pipe 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 301 Chemical Addition Piping 302 Drug release section 303 Chemical Addition Piping Opening and Closing Valve 304 Raw water supply pipe on-off valve 401 Storage room 402 Inlet 403 First water supply port 404 Second water supply port 405 Reclaimed water return piping 406 Reclaimed water return piping on / off valve 501, 501a, 501b Water Softening Module 502 Connecting pipe 503a, 503b, 503c conductivity meter 601 Upstream drain pipe 602 Drain valve 603 Drainage water measurement 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 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 disposed in the neutralization chamber and surrounded by the weakly basic anion exchange resin, the second electrode acting as a cathode during regeneration of the weakly basic anion exchange resin; a control unit for controlling the regeneration of the weakly acidic cation exchange resin and the weakly basic anion exchange resin; The control unit a water softening process in which water to be treated is introduced into the lower part of the water softening chamber and passed through the water softening chamber and the neutralization chamber in this order to obtain soft water; a regeneration process in which current is applied to the first electrode and the second electrode to generate hydrogen ions from the first electrode and hydroxide ions from the second electrode by water electrolysis, and the weakly acidic cation exchange resin is regenerated with the generated hydrogen ions and the weakly basic anion exchange resin is regenerated with the generated hydroxide ions; and a cleaning process in which cations released from the weakly acidic cation exchange resin by the regeneration process are discharged from the water softening chamber and anions released from the weakly basic anion exchange resin are discharged from the neutralization chamber; during or after the regeneration process, the first electrode is connected to a negative electrode, the second electrode is connected to a positive electrode, and an electrode cleaning process is carried out to dissolve solids that have adhered to the surface of the second electrode during the regeneration process.

2. a water volume measuring unit for measuring the volume of the raw water passed through the water softening chamber; a raw water conductivity measuring unit that measures the conductivity of the raw water before contact with the cation exchange resin; a soft water conductivity measuring unit for measuring the conductivity of the neutralized soft water after contact with the anion exchange resin; an adsorption amount estimation unit that estimates the amount of specific ions adsorbed to the water softening chamber, The adsorption amount estimation unit 2. The water softening device according to claim 1, wherein the amount of ions adsorbed to the water softening chamber during the water softening process is estimated based on the amount of raw water measured by the water amount measuring unit, the conductivity of the raw water measured by the raw water conductivity measuring unit, and the conductivity of the neutralized softened water measured by the softened water conductivity measuring unit.

3. The control unit The water softening apparatus according to claim 2 , wherein an execution time of the regeneration process is set based on the amount of ion adsorption estimated by the adsorption amount estimating unit.

4. The water softening apparatus according to claim 1, further comprising an electrolyte input section for inputting electrolytes other than the hydrogen ions and hydroxide ions into the water softening chamber and the neutralization chamber in the regeneration process.

5. The electrolyte input section is The water softening apparatus according to claim 3 , wherein the raw water containing the hardness components is made to flow into the water softening chamber and the neutralization chamber before the energization in the regeneration process.

6. The soft drink purifier according to claim 4, wherein the electrolyte supply unit adds a chemical containing the electrolyte to the raw water. Water treatment equipment.

7. The electrolyte input section is The water softening apparatus according to claim 4, wherein wastewater containing at least one of the cations or the anions discharged in the cleaning process performed before the regeneration process is introduced into the water softening chamber and the neutralization chamber before the energization in the regeneration process.

8. A storage chamber for storing the wastewater is provided, The storage chamber comprises: an inlet provided at an upper portion of the housing for allowing the wastewater to flow into the housing; a first water supply port provided at an upper portion of the housing and configured to discharge the wastewater outside the housing; a second water supply port provided in a lower portion of the housing and supplying the wastewater to the water softening chamber; The water softening device according to claim 7 , wherein the electrolyte input section inputs the wastewater fed from the second water feed port into the water softening chamber.

9. The control unit an adsorption amount estimation unit that determines the amount of ions adsorbed to the water softening chamber; The water softening apparatus according to claim 1 , wherein, in the regeneration process, values ​​of currents applied to the first electrode and the second electrode are controlled based on the amount of ion adsorption estimated by the adsorption amount estimating unit.

10. a timer unit for measuring the elapsed time from the start of the regeneration process; The control unit The water softening device according to claim 9, wherein the current values ​​applied to the first electrode and the second electrode are changed based on the elapsed time measured by the timer.

11. The water softening apparatus according to claim 10, wherein when the elapsed time exceeds a specific first reference value, the current value applied to the first electrode and the second electrode is increased.

12. A voltage measurement unit is provided to measure a voltage when a current is applied, The control unit The water softening device according to claim 9 , wherein the current values ​​applied to the first electrode and the second electrode are changed based on the amount of change in voltage measured by the voltage measuring unit.

13. a plurality of water softening modules each having the water softening chamber, the neutralization chamber, and the diaphragm; an adsorption amount estimation unit for determining the amount of ions adsorbed to the water softening chamber of each module; In the regeneration process, The water softening device according to claim 1, wherein at least one of a current value and a time for which current is applied to each of the water softening modules is changed based on the amount of ion adsorption estimated by the adsorption amount estimating unit.

14. The control unit The water softening apparatus according to claim 1, wherein a drainage process is carried out during the regeneration process to drain the acidic electrolyzed water in the water softening chamber and the alkaline electrolyzed water in the neutralization chamber out of the apparatus.

15. The drainage time, which is the time from the start to the end of the drainage process, is The water softening apparatus according to claim 14, wherein the retention time is longer than the retention time of the raw water, which is the time from when the raw water flows into the water softening chamber until when the raw water flows out of the neutralization chamber.

16. a water volume measuring unit for measuring the volume of the softened water flowing out of the neutralization chamber; The control unit In the drainage process, if the amount of water measured by the water amount measuring unit from the start of the drainage process is less than the volume of the water softening chamber and the neutralization chamber, the execution of the drainage process is continued; The water softening apparatus according to claim 14, wherein the draining process is terminated when the amount of water measured by the water amount measuring unit from the start of the draining process is equal to or greater than the volume of the water softening chamber and the neutralization chamber.

17. The cleaning time, which is the time from the start to the end of the cleaning process, is The water softening apparatus according to claim 1, wherein the retention time is longer than the retention time of the raw water, which is the time from when the raw water flows into the water softening chamber until when the raw water flows out of the neutralization chamber.

18. a water volume measuring unit for measuring the volume of the softened water flowing out of the neutralization chamber; The control unit In the cleaning process, The water softening apparatus according to claim 1, wherein the washing process is terminated when the amount of water measured by the water amount measuring unit from the start of the washing process becomes greater than the volume of the water softening chamber and the neutralization chamber.

19. a raw water conductivity measuring unit that specifies the conductivity of the raw water; a wastewater conductivity measuring unit that determines the conductivity of the wastewater flowing out of the neutralization chamber during the cleaning process; The control unit The water softening apparatus according to claim 1, wherein the cleaning process is terminated when the conductivity of the wastewater determined by the wastewater conductivity measuring unit becomes equal to the conductivity of the raw water determined by the raw water conductivity measuring unit.

20. The control unit During or after the regeneration process, 2. The water softening apparatus according to claim 1, further comprising an electrode cleaning process in which the first electrode is connected to a negative electrode and the second electrode is connected to a positive electrode, and solids attached to the surface of the second electrode are dissolved in the regeneration process.

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