Water treatment device

Abstract

To provide a water treatment device provided with an electric conductivity sensor reducing influence of polarization due to metal ions remaining in treatment water and enabling measurement of appropriate electric conductivity.SOLUTION: A water treatment device 1 includes an electrolysis tank 10 including an anode chamber 15, a cathode chamber 16 and a film partitioning the anode chamber 15 from the cathode chamber 16 and permeating ions, and generating acidic water and alkaline water from the water to be treated by electrolysis. The water treatment device 1 includes: a first electric conductivity measurement part 70; a second electric conductivity measurement part 80; and a control part 100 controlling voltage applied to the anode and the cathode on the basis of the electric conductivity. The first electric conductivity measurement part 70 and / or the second electric conductivity measurement part 80 have / has an electric conductivity sensor 200 provided with a first electrode and a second electrode, and a voltage measurement terminal for voltage measurement. The control part 100 measures resistance of water existing between the first electrode and the second electrode on the basis of the voltage measured by the voltage measurement terminal and calculates an electric conductivity on the basis of measured water resistance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water treatment device. [Background technology]

[0002] Conventionally, devices for producing deionized water from water to be treated have been proposed. Patent Document 1 discloses a conductivity measurement system that includes a conductivity meter that measures the conductivity of decationized water, an electrical decationization device, and a control unit. In the measurement system disclosed in Patent Document 1, the control unit controls the power supply of the electrical decationization device to remove cations, and the conductivity is measured with the conductivity meter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-60631 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when measuring the conductivity of water containing residual ions using a conductivity meter during the process of producing water from which ions have been removed, the electrodes may become polarized due to the influence of the residual ions. Therefore, a conductivity measuring device that reduces the influence of polarization is needed, for example, in water treatment devices that remove metal ions from hard water.

[0005] 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 treatment device equipped with a conductivity sensor that can reduce the influence of polarization due to metal ions remaining in the treated water and measure appropriate conductivity. [Means for solving the problem]

[0006] In order to solve the above problems, a water treatment device according to an embodiment of the present invention is a water treatment device that removes metal ions from water to be treated to produce treated water, and is equipped with an anode chamber having an anode, a cathode chamber having a cathode, and a membrane that separates the anode chamber and the cathode chamber and is permeable to ions, an electrolytic cell that produces acidic water and alkaline water from the water to be treated by electrolysis, a first conductivity measuring unit that measures the conductivity of water flowing into the anode chamber, a second conductivity measuring unit that measures the conductivity of water flowing into the cathode chamber, and a control unit that controls the voltage applied to the anode and cathode based on the conductivity, and the first conductivity measuring unit and / or the second conductivity measuring unit has a conductivity sensor that includes a first electrode and a second electrode and a voltage measurement terminal for voltage measurement, and the control unit measures the resistance of the water present between the first electrode and the second electrode based on the voltage measured by the voltage measurement terminal, and calculates the conductivity based on the measured resistance of the water. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a water treatment device equipped with a conductivity sensor that can reduce the influence of polarization caused by metal ions remaining in the treated water and measure appropriate conductivity. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a water treatment device according to an embodiment of the present invention. [Figure 2] 3 is a schematic diagram showing the state of migration and insolubilization of metal ions in the electrolytic cell of the water treatment device according to the present embodiment. FIG. [Figure 3] 3 is a schematic diagram showing the state of hydrogen ion migration and neutralization in the electrolytic cell of the water treatment device according to the present embodiment. FIG. [Figure 4] 1 is a graph showing the relationship between the abundance ratio of carbon dioxide (H2CO3), bicarbonate ions (HCO3 -), and carbonate ions (CO3 2-) and pH when carbonate ions are dissolved in water. [Figure 5] 4 is a table for explaining electrolysis control in the water treatment device according to the present embodiment. [Figure 6]This is a graph that schematically shows the relationship between the conductivity of the treated water and the ion migration rate, insolubilization rate, and softening rate of metal ions when only constant current control is performed, when only constant voltage control is performed, and when electrolysis control is performed. [Figure 7] 1 is a diagram showing a configuration of a conductivity sensor according to an embodiment of the present invention. [Figure 8A] FIG. 2 is a diagram for explaining the flow of current in the conductivity sensor according to the embodiment. [Figure 8B] FIG. 2 is a diagram for explaining the flow of current in the conductivity sensor according to the embodiment. [Figure 9] FIG. 1 is a circuit diagram showing an example of the configuration of a conductivity sensor according to an embodiment of the present invention. [Figure 10] FIG. 10 is a schematic diagram illustrating an example of the configuration of a water treatment device according to another embodiment. [Figure 11] FIG. 10 is a comparative diagram for explaining a power supply system according to the water treatment device. [Figure 12] FIG. 10 is a diagram illustrating a power supply system of a water treatment device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The water treatment device 1 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0010] The water treatment device 1 of this embodiment is a device that removes and separates metal ions from the water to be treated, thereby reducing the concentration (hardness) of metal ions in the water to a predetermined concentration or less, and producing treated water. 2+ ) and magnesium ions (Mg 2+ ) The definitions of hard water and soft water may be, for example, those of the WHO. That is, soft water may be defined as water with a hardness of less than 120 mg / L, and hard water may be defined as water with a hardness of 120 mg / L or more.

[0011] (Water Treatment Device 1) 1, the water treatment device 1 of this embodiment includes an electrolytic cell 10 that produces acidic water and alkaline water from water to be treated by electrolysis, a first flow path 20 through which the acidic water circulates, and a second flow path 30 through which alkaline water circulates. The water treatment device 1 further includes a water to be treated flow path 40 that supplies the water to be treated, a first outlet flow path 50 through which the treated acidic water flows out from the first flow path 20, and a second outlet flow path 60 through which the treated alkaline water flows out from the second flow path 30.

[0012] 1 and 2, the electrolytic tank 10 includes a solution tank 11, an anode 12, a cathode 13, and an ion-permeable membrane (ion-permeable membrane 14). The solution tank 11 is a container that holds water to be treated that contains metal ions, and electrolyzes the water to be treated held therein, as described below.

[0013] The anode 12 and the cathode 13 are an electrode pair for electrolyzing the water to be treated in the solution tank 11. The anode 12 is provided in an anode chamber 15, and the cathode 13 is provided in a cathode chamber 16. The anode 12 and the cathode 13 are arranged inside the solution tank 11 so as to face each other with an ion-permeable membrane 14 therebetween. The anode 12 is electrically connected to the positive electrode of a power source 90 for electrolysis, and the cathode 13 is electrically connected to the negative electrode of the power source 90 for electrolysis.

[0014] The ion-permeable membrane 14 is disposed in the solution tank 11 and divides the solution tank 11 into an anode chamber 15 and a cathode chamber 16. That is, the anode chamber 15 is partitioned by a portion of the solution tank 11 and the ion-permeable membrane 14, and the cathode chamber 16 is partitioned by another portion of the solution tank 11 and the ion-permeable membrane 14. The ion-permeable membrane 14 is a member through which metal ions in the water to be treated permeate. Therefore, the ion-permeable membrane 14 is not particularly limited as long as it allows metal ions to permeate, and for example, a porous membrane or a cation exchange membrane can be used. The material of the porous membrane is not particularly limited, and may be, for example, a ceramic material, a resin material, or a metal material.

[0015] A first flow path 20 is connected to the anode chamber 15 of the electrolytic cell 10. That is, the first flow path 20 is connected to the inlet 15a and the outlet 15b of the anode chamber 15, respectively. In the first flow path 20, an acidic water tank 21 for temporarily storing acidic water and a first circulation pump 22 for pumping the acidic water are disposed downstream of the anode chamber 15. Therefore, the acidic water flowing out from the outlet 15b of the anode chamber 15 can pass through the acidic water tank 21 and the first circulation pump 22 and flow into the anode chamber 15 from the inlet 15a of the anode chamber 15.

[0016] Similarly, a second flow path 30 is connected to the cathode chamber 16 of the electrolytic cell 10. That is, the second flow path 30 is connected to the inlet 16a and the outlet 16b of the cathode chamber 16, respectively. In the second flow path 30, an alkaline water tank 31 for temporarily storing alkaline water and a second circulation pump 32 for pumping the alkaline water are disposed downstream of the cathode chamber 16. Therefore, the alkaline water flowing out from the outlet 16b of the cathode chamber 16 can pass through the alkaline water tank 31 and the second circulation pump 32 and flow into the cathode chamber 16 from the inlet 16a of the cathode chamber 16.

[0017] The water to be treated flow path 40 is a flow path that supplies the water to be treated to the electrolytic cell 10. Specifically, the water to be treated flow path 40 branches into two flow paths, which are connected to the first flow path 20 and the second flow path 30. Therefore, the water to be treated is supplied to both the first flow path 20 and the second flow path 30 through the water to be treated flow path 40. The water to be treated flow path 40 is provided with an electric valve 41 that switches between allowing the water to be passed and stopping the flow of water to be treated.

[0018] The first outlet flow path 50 is connected to the downstream side of the first circulation pump 22 via a first motor-operated valve 51. As will be described later, the first outlet flow path 50 is a flow path for discharging acidic water that has been softened in the electrolytic cell 10. A water valve 52 is provided at the end of the first outlet flow path 50 to switch between allowing and stopping the flow of acidic water that has been softened. The treated water that has been discharged from the first outlet flow path 50 is treated water in which metal ions have been removed or reduced, and can be suitably used.

[0019] In the water treatment device 1 according to this embodiment, the motor-operated valve 41, the first motor-operated valve 51, the second motor-operated valve 61, and the water faucet 52 are configured as general motor-operated valves driven by actuators using motors (electric motors). However, the valves used in the water treatment device 1 are not limited to motor-operated valves, and may be configured as, for example, electromagnetic valves driven by actuators (solenoids).

[0020] The second outlet flow path 60 is connected to the downstream side of the second circulation pump 32 via a second motor-operated valve 61. As will be described later, the second outlet flow path 60 is a flow path for discharging alkaline water that has been insolubilized in the electrolytic cell 10. The end of the second outlet flow path 60 is connected to a water faucet 52. The water faucet 52 can be used to switch between passing and stopping the alkaline water that has been softened by removing insolubilized matter using the filter 62. The treated water that has been discharged from the second outlet flow path 60 is water in which metal ions have been removed or reduced, and can be used suitably.

[0021] The second outlet flow path 60 is provided with a filter 62 for separating and removing insolubilized matter consisting of metal ions insolubilized in the electrolytic cell 10. The filter 62 is not particularly limited as long as it can remove insolubilized matter, and a cartridge-type filter, a filtration layer using a granular filter medium, a cyclone-type solid-liquid separator, a hollow fiber membrane, etc. can be used.

[0022] 1, a bypass flow path 53 may be connected to the first motor-operated valve 51 for sending the softened acidic water to a filter 62. The acidic water that has been softened in the electrolytic cell 10 and circulating through the first flow path 20 has had insolubilized matter sufficiently reduced, but if necessary, the acidic water may be filtered through the filter 62 before being sent to the faucet 52. A bypass flow path 63 may be connected to the second motor-operated valve 61 for sending the alkaline water that has been insolubilized in the electrolytic cell 10 directly to the faucet 52 without sending it to the filter 62.

[0023] As shown in FIG. 1 , the water treatment device 1 of this embodiment includes a first conductivity measuring unit 70 that measures the conductivity of water flowing through the anode chamber and a second conductivity measuring unit 80 that measures the conductivity of water flowing through the cathode chamber. In this specification, the water flowing through the anode chamber is also referred to as anode water, and the water flowing through the cathode chamber is also referred to as cathode water. The first conductivity measuring unit 70 is provided on the inlet 15a side of the anode chamber 15 in the first flow path 20, and the second conductivity measuring unit 80 is provided on the inlet 16a side of the cathode chamber 16 in the second flow path 30. However, the location where the first conductivity measuring unit 70 is installed is not particularly limited as long as it can measure the conductivity of the anode water. For example, the first conductivity measuring unit 70 may be installed inside the anode chamber 15 or inside the acidic water tank 21. Similarly, the second conductivity measuring unit 80 may be installed in any location as long as it can measure the conductivity of the cathode water; for example, it may be installed inside the cathode chamber 16 or inside the alkaline water tank 31.

[0024] A conductivity sensor 200 (see FIG. 7) can be used as the first conductivity measuring unit 70 and the second conductivity measuring unit 80. Details of the conductivity sensor 200 will be described later.

[0025] The first conductivity measuring unit 70 and the second conductivity measuring unit 80 are connected to the control unit 100 described later, and transmit the numerical values ​​of the conductivity of the anode water and the conductivity of the cathode water measured by the first conductivity measuring unit 70 and the second conductivity measuring unit 80 to the control unit 100.

[0026] The water treatment device 1 further includes an electrolysis power supply 90 and a control unit 100. The electrolysis power supply 90 is electrically connected to the anode 12 and the cathode 13. The electrolysis power supply 90 passes a current between the anode 12 and the cathode 13 and applies a voltage therebetween.

[0027] The control unit 100 is connected to the electrolysis power supply 90 and adjusts the voltage between the anode and the cathode by controlling the electrolysis power supply 90. The control unit 100 is also connected to the motor-operated valve 41, the first motor-operated valve 51, the second motor-operated valve 61, and the water faucet 52 in the treatment water flow path 40 and controls the opening and closing of these. The control unit 100 is also connected to the first circulation pump 22 and the second circulation pump 32 and controls their operation.

[0028] When the control unit 100 executes operations based on a control program, it may include a storage device such as a ROM (Read Only Memory) or a RAM (Random Access Memory) that stores the control program. The control unit 100 may also include a CPU (Central Processing Unit) that executes the control program. When the control unit 100 executes predetermined operations, it may also include a dedicated electronic circuit or the like that realizes the control program in hardware. Furthermore, the control unit 100 may also include a timer such as an RTC (Real Time Clock) to measure time.

[0029] The operation of the water treatment device 1 configured as above is premised on the following facts. First, the conductivity of acidic water is proportional to the ion concentration in the acidic water. Therefore, the conductivity of acidic water is proportional to the concentration of metal ions (hardness) contained in the acidic water. Similarly, the conductivity of alkaline water is proportional to the ion concentration in the alkaline water. Therefore, the conductivity of alkaline water is proportional to the concentration of metal ions (hardness) contained in the alkaline water.

[0030] Next, when a voltage is applied to the anode 12 and the cathode 13 with the water to be treated placed in the anode chamber 15 and the cathode chamber 16 of the electrolytic cell 10, the metal ions in the anode chamber 15 permeate the ion-permeable membrane 14 and move to the cathode chamber 16, as shown in Figure 2. In other words, as shown in the electrophoretic velocity equation in Equation 1, the electrophoretic velocity of ions, ν (m / s), is proportional to the ion mobility, μ (m 2 The voltage is expressed as the product of the voltage (V / Vs) and the electric field E (V / m). Therefore, the movement of metal ions depends on the magnitude of the voltage (electric field). As shown in FIG. 3, when a voltage is applied to the anode 12 and the cathode 13, the hydrogen ions (H + ) also moves to the cathode chamber 16, and hydroxide ions (OH - ) and neutralizes it. [Number 1] ν=μE

[0031] Next, when the water to be treated is placed in the anode chamber 15 and the cathode chamber 16 of the electrolytic cell 10 and electrolyzed, hydrogen ions (H + ) is generated at the cathode 13 by a reduction reaction, and hydroxide ions (OH - ) is produced. Note that this type of water electrolysis depends on the magnitude of the current. [C1] Anode 12:2H2O → 4H + +4e - +O2↑ Cathode 13:4H2O+4e - → 4OH - +2H2↑

[0032] The magnesium ions (Mg 2+ ) reacts with the generated hydroxide ions to become magnesium hydroxide (Mg(OH)2), which becomes insoluble. Here, the solubility product K of magnesium hydroxide in water at 25°C is sp is 1.80 x 10 -11 (mol / L) 3 As shown in Equation 2, Mg 2+ and OH - The ionic product of this is the solubility product K spIf the pH is greater than 1, the dissolution equilibrium shifts in favor of the formation of Mg(OH)2, resulting in the formation of an insolubilized product consisting of Mg(OH)2. Therefore, to efficiently insolubilize magnesium ions, it is necessary to increase the pH, i.e., to increase the hydroxide ions. [Number 2] K sp <[Mg 2+ ][OH - ] 2

[0033] In addition, carbonate ions (CO3 2- ) contained in the treated water. 2+ ) reacts with carbonate ions to become insoluble as calcium carbonate (CaCO3). Here, the solubility product K of calcium carbonate in water at 25°C is sp is 4.96 x 10 -9 (mol / L) 2 Then, as shown in Equation 3, Ca 2+ and CO3 - The ionic product of this is the solubility product K sp When the temperature becomes larger than 100°C, the dissolution equilibrium shifts in the direction of CaCO3 production, resulting in the production of an insolubilized product consisting of CaCO3. [Number 3] K sp <[Ca 2+ ][CO3 - ]

[0034] In Figure 4, when carbonate ions are dissolved in water, carbonic acid (H2CO3) and bicarbonate ions (HCO3 - ) and carbonate ions (CO3 2- ) and pH. Figure 4 shows that the more alkaline the water pH, the fewer the carbonate and bicarbonate ions and the more carbonate ions there are. Therefore, to efficiently insolubilize calcium ions, it is necessary to increase the pH and increase the carbonate ions.

[0035] Thus, the insolubilization of magnesium ions and calcium ions increases with increasing hydroxide ion concentration. Furthermore, the electrolysis of water depends on the magnitude of the electric current. Therefore, the insolubilization of magnesium ions and calcium ions depends on the magnitude of the electric current.

[0036] Next, the operation of the water treatment device 1 of this embodiment will be described based on the above events. First, the control unit 100 opens the motor-operated valve 41 and injects raw water (water to be treated) into the water-to-be-treated flow path 40, the first flow path 20, and the second flow path 30. Then, the water to be treated is injected into the anode chamber 15 and the cathode chamber 16 of the electrolytic cell 10, the acidic water tank 21, and the alkaline water tank 31.

[0037] Next, the control unit 100 measures the conductivity of the anode water and the cathode water using the first conductivity measuring unit 70 and the second conductivity measuring unit 80. Furthermore, the control unit 100 controls the electrolysis power supply 90 to pass a current between the anode 12 and the cathode 13, electrolyzing the water to be treated. The control unit 100 also operates the first circulation pump 22 and the second circulation pump 32 to circulate the water to be treated through the first flow path 20 and the second flow path 30. By performing electrolysis and circulation of the water to be treated for a predetermined time, the water to be treated in the anode chamber 15, the first flow path 20, and the acidic water tank 21 becomes acidic water, and the water to be treated in the cathode chamber 16, the second flow path 30, and the alkaline water tank 31 becomes alkaline water.

[0038] The control unit 100 then measures the conductivity of the anode water (acidic water) and the cathode water (alkaline water) at predetermined time intervals. When almost no metal ions have been removed from the acidic water or alkaline water, both the acidic water and the alkaline water have high conductivity, as shown in "(1) Formation of insolubilized matter" in FIG. 5 . Therefore, the control unit 100 controls the electrolysis power supply 90 to pass a constant current between the anode 12 and the cathode 13. Such constant current control can be achieved by adjusting the current or voltage applied between the anode 12 and the cathode 13.

[0039] As mentioned above, the insolubilization of metal ions is current-dependent, so constant current control promotes the insolubilization of metal ions in alkaline water. As a result, the concentration of metal ions decreases, and the conductivity of alkaline water decreases. However, in acidic water, the insolubilization of metal ions is less likely to occur, so the conductivity remains high.

[0040] Next, if the conductivity measurement shows that the conductivity of the alkaline water has decreased but the conductivity of the acidic water remains high, the control unit 100 controls the electrolysis power supply 90 to apply a constant voltage between the anode 12 and the cathode 13, as shown in "(2) Ion migration" in Figure 5. Note that such constant voltage control can be performed by adjusting the voltage applied between the anode 12 and the cathode 13.

[0041] As described above, electrophoresis, in which metal ions move from the anode chamber 15 to the cathode chamber 16, is voltage-dependent, so when constant voltage control is performed, metal ions in the acidic water in the anode chamber 15 permeate the ion-permeable membrane 14 and move to the cathode chamber 16. As a result, the metal ion concentration in the alkaline water in the cathode chamber 16 increases, and the conductivity of the alkaline water increases. In contrast, the metal ion concentration in the acidic water decreases, and the conductivity of the acidic water decreases.

[0042] Here, as described above, when a constant voltage is applied to the anode 12 and the cathode 13, the hydrogen ions (H + ) also moves to the cathode chamber 16, causing a neutralization reaction and lowering the pH. If the pH of the alkaline water in the cathode chamber 16 drops, the insolubilization of metal ions is suppressed. Therefore, when the control unit 100 measures the conductivity after performing constant current control and finds that the conductivity of the alkaline water has dropped but the conductivity of the acidic water is high, it calculates a voltage value that will maintain the pH of the alkaline water at a high level. For example, the control unit 100 calculates and applies a voltage value that will maintain the pH of the alkaline water at 11 or higher.

[0043] Next, if the conductivity measurement shows that the conductivity of the alkaline water has increased but that of the acidic water has decreased, the control unit 100 controls the electrolysis power supply 90 to pass a constant current between the anode 12 and the cathode 13, as shown in "(3) Formation of insolubilized matter" in Figure 5. Note that such constant current control can be performed by adjusting the current or voltage applied between the anode 12 and the cathode 13.

[0044] As mentioned above, since the insolubilization of metal ions is current-dependent, constant current control promotes the insolubilization of metal ions in alkaline water, which results in a decrease in the concentration of metal ions and a decrease in the conductivity of the alkaline water.

[0045] Next, if the conductivity measurement shows that the conductivity of both the acidic water and the alkaline water has decreased, the control unit 100 determines that softening of both the acidic water and the alkaline water has progressed, as shown in "(4) Softening" in Figure 5.

[0046] In this way, the control unit 100 measures the conductivity of the anode water and the cathode water, and then adjusts the voltage applied between the anode 12 and the cathode 13 to perform electrolysis control that alternates between constant current control and constant voltage control. As a result, metal ions on the acidic water side electrophorese to the alkaline water side, and the metal ions are insolubilized on the alkaline water side, thereby reducing the metal ions in the water to be treated. In this embodiment, the timer of the control unit 100 measures the time during which electrolysis control is performed, and therefore the electrolysis control is performed until a predetermined time has elapsed.

[0047] The control unit 100 then adjusts the first motor-operated valve 51 to allow the acidic water in the first flow path 20 to flow into the first outlet flow path 50. The control unit 100 also adjusts the second motor-operated valve 61 to allow the alkaline water in the second flow path 30 to flow into the second outlet flow path 60. The alkaline water then passes through a filter 62 provided in the second outlet flow path 60. Because the alkaline water flowing into the second outlet flow path 60 contains insoluble metal ions, the insoluble matter is removed by passing the alkaline water through the filter 62. By opening the water faucet 52, the user can consume the softened acidic water and alkaline water. At this time, the acidic water and alkaline water can be mixed as desired to produce neutral treated water.

[0048] FIG. 6 shows the relationship between the conductivity of the water to be treated and the ion migration rate, insolubilization rate, and water softening rate of metal ions when the control unit 100 only performs constant voltage control, in which a constant voltage is applied to the anode 12 and cathode 13 of the electrolytic cell 10 regardless of the conductivity. FIG. 6 also shows the relationship between the conductivity of the water to be treated and the ion migration rate, insolubilization rate, and water softening rate of metal ions when the control unit 100 only performs constant current control, in which a constant current is applied to the anode 12 and cathode 13 of the electrolytic cell 10 regardless of the conductivity. The "ion migration rate of metal ions" indicates the efficiency at which metal ions migrate from the anode chamber 15 to the cathode chamber 16. The "insolubilization rate of metal ions" indicates the efficiency at which metal ions bind with hydroxide ions and carbonate ions to become insolubilized. The "water softening rate" indicates the efficiency at which metal ions are removed from the water to be treated.

[0049] As described above, because the movement of metal ions depends on the voltage (electric field), when the control unit 100 performs constant voltage control, metal ions move from the anode chamber 15 to the cathode chamber 16 regardless of the conductivity of the water being treated. This means that a high ion migration rate can be maintained. However, because the insolubilization of metal ions depends on the current, constant voltage control improves the insolubilization rate when the conductivity of the water being treated is high, but decreases the insolubilization rate when the conductivity is low. Therefore, if the control unit 100 only performs constant voltage control and not constant current control, the water being treated can be efficiently softened and the water softening rate increased when the conductivity of the water being treated is high, i.e., when the metal ion concentration is high. However, when the conductivity of the water being treated is low, i.e., when the metal ion concentration is low, the insolubilization rate decreases, and therefore the water softening rate also decreases. Thus, when the control unit 100 only performs constant voltage control, the water softening rate is good when the metal ion concentration is high, but the water softening rate deteriorates when the metal ion concentration is low.

[0050] In contrast, because the insolubilization of metal ions depends on the current, when the control unit 100 performs constant current control, metal ions are insolubilized regardless of the conductivity of the water being treated, i.e., a high insolubilization rate can be maintained. However, as described above, because the migration of metal ions depends on the voltage, when constant current control is performed, the ion migration rate improves when the conductivity of the water being treated is low, but decreases when the conductivity is high. Therefore, if the control unit 100 only performs constant current control and not constant voltage control, the water being treated can be efficiently softened and the water softening rate increased when the conductivity of the water being treated is low, i.e., when the metal ion concentration is low. However, when the conductivity of the water being treated is high, i.e., when the metal ion concentration is high, the ion migration rate decreases, and the water softening rate also decreases. Thus, when the control unit 100 only performs constant current control, the water softening rate is good when the metal ion concentration is low, but the water softening rate deteriorates when the metal ion concentration is high.

[0051] In the water treatment device 1 of this embodiment, the voltage applied between the anode 12 and the cathode 13 is adjusted according to the conductivity (hardness) of the anode water and the cathode water, and electrolysis control is performed by repeating constant current control and constant voltage control. This keeps the ion migration rate and insolubilization rate high at all times, and as a result, it becomes possible to obtain a desired water softening rate regardless of the conductivity.

[0052] Furthermore, in the water treatment device 1 of this embodiment, the first flow path 20 and the second flow path 30 are circulation flow paths. However, the water treatment device is not limited to this configuration, and the first flow path and the second flow path may be one-pass flow paths that do not circulate water. Furthermore, the first flow path and the second flow path may be a combination of a circulation flow path and a one-pass flow path. Therefore, in this specification, the circulation flow path and the one-pass flow path are collectively referred to as the "first flow path." Similarly, the circulation flow path and the one-pass flow path are collectively referred to as the "second flow path."

[0053] (Conductivity Sensor 200) Next, the conductivity sensors 200 provided in the first conductivity measuring unit 70 and the second conductivity measuring unit 80 of the water treatment device 1 of this embodiment will be described in detail.

[0054] Fig. 7 is a diagram showing the configuration of a conductivity sensor 200 according to this embodiment. As shown in Fig. 7, the conductivity sensor 200 includes a power supply 210, a first switch SW1, a second switch SW2, a third switch SW3, and a fourth switch SW4. The conductivity sensor 200 also includes a first resistor R1, a second resistor R2, a first electrode E1, a second electrode E2, a first terminal T1, and a second terminal T2.

[0055] The power supply 210 is a power supply for the conductivity sensor 200, and is provided in, for example, the control unit 100. One end of the first switch SW1 is connected to the power supply 210, and the other end is connected to the first resistor R1. Furthermore, one end of the second switch SW2 is connected to the power supply 210, and the other end is connected to the second resistor R2.

[0056] The first resistor R1 has one end connected to the first switch SW1 and the other end connected to the first node N1. That is, the first switch SW1 and the first resistor R1 are connected in series between the power supply 210 and the first node N1.

[0057] The second resistor R2 has one end connected to the second switch SW2 and the other end connected to the second node N2. That is, the second switch SW2 and the second resistor R2 are connected in series between the power supply 210 and the second node N2.

[0058] The third switch SW3 has one end connected to the first node N1 and the other end connected to GND, and the fourth switch SW4 has one end connected to the second node N2 and the other end connected to GND.

[0059] A first electrode E1 for measuring the water resistance Rx is connected to a first node N1. A second electrode E2 is connected to a second node N2. The water resistance Rx corresponds to the resistance of the water between the first electrode E1 and the second electrode E2. In the example shown in FIG. 7, the water resistance Rx is schematically shown as a resistive element. The water resistance measuring unit corresponds to a configuration including the first electrode E1 and the second electrode E2.

[0060] The first terminal T1 is a terminal for reading voltage that is connected to the control unit 100, and one end is connected to the first node N1. Similarly to the first terminal T1, the second terminal T2 is also a terminal for reading voltage that is connected to the control unit 100, and one end is connected to the second node N2. The first terminal T1 and the second terminal T2 correspond to voltage measurement terminals for measuring voltage.

[0061] (Example of operation of the conductivity sensor 200) Next, the operation of the conductivity sensor 200 will be described with reference to Figures 8A and 8B. In the example shown in Figure 8A, during a first period, the first switch SW1 and the fourth switch SW4 are turned on, and the second switch SW2 and the third switch SW3 are turned off. As a result, a current flows from the power supply 210 to GND in the direction of the arrow shown in Figure 8A via the water resistance Rx. The control unit 100 measures the first voltage Vout1 from the first terminal T1. The relationship between the first voltage Vout1 and the water resistance Rx is expressed by the following equation 4. [Number 4] Vout1 = (water resistance Rx / (first resistance R1 + water resistance Rx)) x power supply voltage

[0062] Here, the first resistance R1 and the power supply voltage are preset or measured values, and the resistance Rx of water can be measured using the first resistance R1, the power supply voltage, and the first voltage Vout1.

[0063] In the example shown in Fig. 8B, during the second period, the first switch SW1 and the fourth switch SW4 are turned off, and the second switch SW2 and the third switch SW3 are turned on. As a result, current flows from the power supply 210 to GND in the direction of the arrow shown in Fig. 8B via the water resistance Rx. The control unit 100 measures the second voltage Vout2 from the second terminal T2. The relationship between the second voltage Vout2 and the water resistance Rx is expressed by the following equation 5. [Number 5] Vout2 = (water resistance Rx / (second resistor R2 + water resistance Rx)) x power supply voltage

[0064] Here, the second resistance R2 and the power supply voltage are preset or measured values, and the resistance Rx of water can be measured using the second resistance R2, the power supply voltage, and the second voltage Vout2.

[0065] The conductivity sensor 200 according to this embodiment alternates between a first period state shown in FIG. 8A and a second period state shown in FIG. 8B at a predetermined cycle under the control of the control unit 100. This predetermined cycle is, for example, 1 / 60 seconds, which corresponds to a frequency of 60 Hz. Thus, the conductivity sensor 200 according to this embodiment switches the current flow at a set frequency, thereby reducing the influence of polarization in the electrode of the water resistance Rx and enabling more accurate conductivity measurement. The cycle for switching between the first period and the second period is not limited to 1 / 60 seconds, but may be longer or shorter than 1 / 60 seconds.

[0066] Furthermore, the first switch SW1 to the fourth switch SW4 of the conductivity sensor 200 may be configured with electronic switches such as bipolar transistors or FETs (Field-Effect Transistors). Fig. 8 is a circuit diagram showing an example in which the first switch SW1 to the fourth switch SW4 of the conductivity sensor 200 are configured with MOS (Metal Oxide Semiconductor) FETs. By configuring the first switch SW1 to the fourth switch SW4 with electronic switches in this way, it becomes possible to more appropriately and accurately switch between the first period and the second period, and it becomes possible to measure the conductivity more accurately.

[0067] In the above-described configuration, the control unit 100 measures the first voltage Vout1 at the first terminal T1 during the first period shown in FIG. 8A and measures the second voltage Vout2 at the second terminal T2 during the second period shown in FIG. 8B. The configuration of this embodiment is not limited to measuring both the first voltage Vout1 and the second voltage Vout2, but may instead measure either the first voltage Vout1 during the first period or the second voltage Vout2 during the second period. This configuration enables the water treatment device 1 to reduce circuit size and power consumption.

[0068] 1 , the conductivity sensor 200 is configured as the first conductivity measurement unit 70 and the second conductivity measurement unit 80 to be installed upstream of the electrolytic bath 10, but the embodiment is not limited to this configuration. For example, the first conductivity measurement unit 70 and the second conductivity measurement unit 80 equipped with the conductivity sensor 200 may be installed downstream of the electrolytic bath 10. Furthermore, the first conductivity measurement unit 70 and the second conductivity measurement unit 80 equipped with the conductivity sensor 200 may be installed inside the electrolytic bath 10. Furthermore, a plurality of the first conductivity measurement unit 70 and the second conductivity measurement unit 80 equipped with the conductivity sensor 200 may be installed upstream, downstream, and / or inside the electrolytic bath 10.

[0069] For example, by installing the conductivity sensor 200 upstream of the electrolytic bath 10, it becomes possible to efficiently use the measured conductivity to control the electrolytic bath 10. Furthermore, by installing the conductivity sensor 200 downstream of the electrolytic bath 10, it becomes possible to confirm the effect of the treatment in the electrolytic bath 10. Furthermore, by installing the conductivity sensor 200 inside the electrolytic bath 10, it becomes possible to calculate the effect of the treatment in the electrolytic bath 10 in real time.

[0070] As described above, the water treatment device 1 according to this embodiment uses the conductivity sensor 200 that can appropriately measure the conductivity, thereby enabling accurate control of electrolysis in the electrolytic cell 10.

[0071] (Other embodiments) Although the present embodiment has been described above, the present embodiment is not limited to these, and various modifications are possible within the scope of the gist of the embodiment. Furthermore, it is also possible to combine some or all of the various embodiments to create a new embodiment.

[0072] For example, a configuration will be described in which current flow from the electrodes of the electrolytic cell 10 to the electrodes of the conductivity sensor 200 is suppressed, thereby suppressing errors in the conductivity measurement by the conductivity sensor 200. Fig. 10 is a diagram showing the configuration of a water treatment device 1 according to another embodiment. As shown in Fig. 10, the water treatment device 1 according to the other embodiment has an insulating unit 300 provided between the control unit 100 and the power supply 90 for electrolysis.

[0073] The power supply system of the water treatment device 1 will be described below, followed by a detailed description of the water treatment device 1 according to another embodiment.

[0074] (Power supply system of water treatment device 1) First, the power supply system of the water treatment device 1 of this embodiment will be described. Fig. 11 is a comparative diagram showing a general configuration of the power supply system in the water treatment device 1. Power supplied from a main power supply 9 is converted into power for the electrolytic cell 10 in an electrolysis power supply 90. The electrolysis power supply 90 may be configured, for example, by a transformer that converts power supplied to the primary side and supplies it to the secondary side.

[0075] The power generated by the electrolysis power supply 90 is supplied to the electrolytic cell 10 via a first signal line L1a. In Fig. 11, a first GND line L1b indicates a ground line. The first signal line L1a and the first GND line L1b correspond to the electrolytic cell signal line L1 shown in Fig. 10.

[0076] Furthermore, power supplied from the main power supply 9 is converted into power for the control unit 100 in the control unit power supply 92. The control unit power supply 92 may be configured, for example, by a transformer that converts power supplied to its primary side and supplies it to its secondary side. The power generated by the control unit power supply 92 is supplied to the control unit 100 via a fourth signal line L4a. Note that a fourth GND line L4b in FIG. 11 indicates a ground line.

[0077] The control unit 100 also supplies power to the electrodes of the electrode sensors provided in the first conductivity measurement unit 70 and the second conductivity measurement unit 80 via the second signal line L2a, and receives the measurement result as a measurement current I1 for measurement via the second GND line L2b at the measurement unit 120. The microcomputer 110 of the control unit 100 determines the power to be applied to the electrolytic cell 10 according to the conductivity measured by the measurement unit 120. The second signal line L2a and the second GND line L2b correspond to the conductivity sensor signal line L2 shown in FIG.

[0078] The control unit 100 controls the power supplied to the electrolysis cell 10 from the electrolysis power supply 90 via the third signal line L3a. In Fig. 11, the third GND line L3b indicates a ground line. The third signal line L3a and the third GND line L3b correspond to the power supply signal line L3 shown in Fig. 10.

[0079] 11, a comparative example showing a power supply system of a typical water treatment device may cause sneak current I2 from electrolytic cell 10 to sneak into the electrodes of the conductivity sensor. This sneak current I2 sneaking into the conductivity sensor may cause an error in measurement current I1, preventing measurement unit 120 from measuring the conductivity appropriately.

[0080] As shown in FIG. 12 , the water treatment device 1 according to this embodiment has an insulating unit 300 provided between the control unit 100 and the electrolysis power supply 90. That is, in the example shown in FIG. 12 , the control unit 100 and the insulating unit 300 are connected by a third signal line L3a2 and a third GND line L3b2, and the insulating unit 300 and the electrolysis power supply 90 are connected by a third signal line L3a1 and a third GND line L3b1. That is, the insulating unit 300 is provided between the control unit 100 and the electrolysis power supply 90 at a position that insulates the power supply signal line and the power supply GND line connected to the control unit 100 and the electrolysis power supply 90. The third GND line L3b1 and the third GND line L3b2 correspond to the power supply GND line. The third signal line L3a1 and the third signal line L3a2 correspond to the power supply signal line L3.

[0081] As a result, the water treatment device 1 according to this embodiment can insulate the electrolysis power supply 90 from the first conductivity measuring unit 70 and the second conductivity measuring unit 80 by the insulating unit 300.

[0082] Note that, when digital signals are transmitted through the third signal lines L3a1 and L3a2, the insulating unit 300 may be configured with an insulating circuit such as a general photocoupler. This makes it possible for the water treatment device 1 according to this embodiment to suppress sneak current from the electrodes of the electrolytic cell 10 to the electrodes of the conductivity sensor when the control signal from the control unit 100 to the electrolysis power supply 90 is a digital signal.

[0083] Furthermore, when analog signals are transmitted through the third signal lines L3a1 and L3a2, the insulating unit 300 may be configured with an insulating circuit such as a general analog signal isolator. This makes it possible for the water treatment device 1 according to this embodiment to suppress sneak current from the electrodes of the electrolytic cell 10 to the electrodes of the conductivity sensor when the control signal from the control unit 100 to the electrolysis power supply 90 is an analog signal.

[0084] In other words, the water treatment device 1 according to this embodiment is capable of suppressing the generation of sneak current I2 from the electrolytic cell 10 to the conductivity sensor, thereby enabling more accurate conductivity measurements and more appropriate power supply control for the electrolytic cell 10.

[0085] In the water treatment device 1 according to the present embodiment, the insulating unit 300 is configured between the control unit 100 and the electrolysis power supply 90, between the third signal line L3a1 and the third GND line L3b1, and between the third signal line L3a2 and the third GND line L3b2. This configuration does not limit the configuration of the embodiment, and for example, the insulating unit 300 may be configured to be provided between the control unit 100 and the conductivity sensor, between the second signal line L2a and the second GND line L2b.

[0086] That is, the insulating unit 300 may be provided between the control unit 100 and the first conductivity measurement unit 70 and the second conductivity measurement unit 80. The insulating unit 300 may also be provided at a position that insulates the conductivity sensor signal line and the conductivity sensor GND line connected to the control unit 100 and the first conductivity measurement unit 70 and the second conductivity measurement unit 80. This directly prevents the introduction of errors due to the sneak current I2 sneaking into the measurement current I1. A plurality of insulating units 300 may also be provided between the control unit 100 and the electrolysis power supply 90, and between the control unit 100 and the first conductivity measurement unit 70 and the second conductivity measurement unit 80.

[0087] (Addendum) The above description of the embodiments discloses the following techniques.

[0088] (Technology 1) A water treatment device that removes metal ions from water to be treated to produce treated water, an electrolytic cell that includes an anode chamber having an anode, a cathode chamber having a cathode, and a membrane that separates the anode chamber and the cathode chamber and is permeable to ions, and that produces acidic water and alkaline water from the water to be treated by electrolysis; a first conductivity measuring unit that measures the conductivity of water flowing through the anode chamber; a second conductivity measuring unit that measures the conductivity of water flowing through the cathode chamber; a control unit that controls voltages applied to the anode and the cathode based on the conductivity, the first conductivity measurement unit and / or the second conductivity measurement unit has a conductivity sensor including a first electrode, a second electrode, and a voltage measurement terminal for voltage measurement; The control unit measures the resistance of the water present between the first electrode and the second electrode based on the voltage measured by the voltage measurement terminal, and calculates the conductivity based on the measured resistance of the water.

[0089] The water treatment device 1 of this embodiment uses the conductivity sensor 200 that can appropriately measure the conductivity, making it possible to accurately control electrolysis in the electrolytic cell 10.

[0090] (Technology 2) The water treatment device described in Technology 1, wherein the control unit switches the direction of the current flowing through the first electrode and the second electrode at predetermined intervals and calculates the conductivity based on the voltage measured by the voltage measurement terminal.

[0091] In this embodiment, the conductivity sensor 200 reduces the influence of polarization in the electrodes of the water resistance Rx by switching the direction of the current, making it possible to measure conductivity more accurately.

[0092] (Technology 3) The conductivity sensor is Power supply and a first switch connected to the power source; a first resistor having one end connected to the first switch and the other end connected to a first node; a second switch connected to the power source; a second resistor having one end connected to the second switch and the other end connected to a second node; a third switch having one end connected to the first node and the other end connected to GND; a fourth switch having one end connected to the second node and the other end connected to GND; a water resistance measuring unit having the first electrode connected to the first node and the second electrode connected to the second node; The water treatment device according to Technology 1 or 2, wherein the voltage measurement terminals include a first terminal connected to the first node and a second terminal connected to the second node.

[0093] This configuration enables the conductivity sensor 200 to reduce the effect of polarization at the electrodes of the water resistance Rx and measure conductivity more accurately, and enables the water treatment device 1 to accurately control electrolysis in the electrolytic cell 10.

[0094] (Technical 4) The water treatment device according to Technical 3, wherein the control unit measures the conductivity by measuring the voltage of either the first terminal or the second terminal.

[0095] With this configuration, the water treatment device 1 can achieve a reduction in circuit scale and low power consumption.

[0096] (Technology 5) The water treatment device according to any one of Technologies 1 to 4, wherein the conductivity sensor is installed upstream of the electrolytic cell.

[0097] With this configuration, the water treatment device 1 has the conductivity sensor 200 installed upstream of the electrolytic cell 10, and thus the measured conductivity can be used to control the electrolytic cell 10 efficiently.

[0098] (Technology 6) The water treatment device according to any one of Technologies 1 to 5, wherein the conductivity sensor is installed downstream of the electrolytic cell.

[0099] With this configuration, the water treatment device 1 can confirm the effect of treatment in the electrolytic bath 10 by installing the conductivity sensor 200 downstream of the electrolytic bath 10.

[0100] (Technology 7) The water treatment device according to any one of Technologies 1 to 6, wherein the conductivity sensor is installed inside the electrolytic cell.

[0101] With this configuration, the water treatment device 1 is able to calculate the effect of treatment in the electrolytic bath 10 in real time by installing the conductivity sensor 200 inside the electrolytic bath 10.

[0102] (Technology 8) An electrolysis power supply that applies the voltage to the anode and the cathode of the electrolytic cell under control of the control unit; The water treatment device according to any one of techniques 1 to 7, further comprising an insulating unit for insulating the electrolysis power supply from the first conductivity measuring unit and the second conductivity measuring unit.

[0103] The water treatment device 1 is provided with an insulating section 300 for insulating the electrolysis power supply 90 from the first conductivity measuring section 70 and the second conductivity measuring section 80, thereby making it possible to suppress current leakage from the electrodes of the electrolytic cell 10 to the electrodes of the conductivity sensor.

[0104] (Technical 9) The water treatment device according to Technical 8, wherein the insulating unit is provided between the control unit and the electrolysis power supply at a position that insulates a power supply signal line and a power supply GND line connected to the control unit and the electrolysis power supply.

[0105] In the present embodiment, the water treatment device 1 can insulate the electrolysis power supply 90 from the first conductivity measuring unit 70 and the second conductivity measuring unit 80 by the insulating unit 300.

[0106] (Technology 10) The water treatment device according to Technology 8 or 9, wherein the insulating unit is provided between the control unit and the first conductivity measuring unit and the second conductivity measuring unit, in a position that insulates the signal line for the conductivity sensor and the GND line for the conductivity sensor that are connected to the control unit and the first conductivity measuring unit and the second conductivity measuring unit.

[0107] With this configuration, the water treatment device 1 can directly prevent an error from being introduced into the measurement current I1 for measurement due to the sneak current I2 sneaking in.

[0108] (Technology 11) The water treatment device according to any one of Technologies 8 to 10, wherein the insulating part is configured by a photocoupler.

[0109] With this configuration, the water treatment device 1 can suppress sneak current from the electrodes of the electrolytic cell 10 to the electrodes of the conductivity sensor when the control signal from the control unit 100 to the electrolysis power supply 90 is a digital signal.

[0110] (Technology 12) The water treatment device according to any one of Technologies 8 to 11, wherein the insulating section is configured by an analog signal isolator.

[0111] With this configuration, the water treatment device 1 can suppress sneak current from the electrodes of the electrolytic cell 10 to the electrodes of the conductivity sensor when the control signal from the control unit 100 to the electrolysis power supply 90 is an analog signal.

[0112] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0113] 1. Water treatment equipment 10 Electrolytic cell 12 Anode 13 Cathode 14 Ion-permeable membrane 15 Anode chamber 16 Cathode Chamber 20 First Channel 30 Second Channel 70 First conductivity measuring unit 80 Second conductivity measuring unit 100 control section 110 Microcomputer 120 Measuring section 200 Conductivity Sensor 210 Power supply 300 Insulation SW1 First switch SW2 Second switch E1 1st electrode E2 2nd electrode R1 First resistor R2 2nd resistor Rx Water Resistance SW1 First switch SW2 Second switch SW3 Third switch SW4 4th switch T1 Terminal 1 T2 Terminal 2 L1 Signal line for electrolytic cell L1a First signal line L1b 1st GND line L2 Conductivity sensor signal line L2a 2nd signal line L2b 2nd GND line L3 Power supply signal line L3a, L3a1, L3a2 3rd signal line L3b, L3b1, L3b2 3rd GND line L4a 4th signal line L4b 4th GND line

Claims

1. A water treatment device that removes metal ions from water to be treated to produce treated water, an electrolytic cell that includes an anode chamber having an anode, a cathode chamber having a cathode, and a membrane that separates the anode chamber and the cathode chamber and is permeable to ions, and that produces acidic water and alkaline water from the water to be treated by electrolysis; a first conductivity measuring unit that measures the conductivity of water flowing through the anode chamber; a second conductivity measuring unit that measures the conductivity of water flowing through the cathode chamber; a control unit that controls voltages applied to the anode and the cathode based on the conductivity, the first conductivity measurement unit and / or the second conductivity measurement unit has a conductivity sensor including a first electrode, a second electrode, and a voltage measurement terminal for voltage measurement; The control unit measures the resistance of the water present between the first electrode and the second electrode based on the voltage measured at the voltage measurement terminal, and calculates the conductivity based on the measured resistance of the water.

2. The water treatment device according to claim 1 , wherein the control unit switches the direction of the current flowing through the first electrode and the second electrode at a predetermined cycle, and calculates the conductivity based on the voltage measured at the voltage measurement terminal.

3. The conductivity sensor comprises: Power supply and a first switch connected to the power source; a first resistor having one end connected to the first switch and the other end connected to a first node; a second switch connected to the power source; a second resistor having one end connected to the second switch and the other end connected to a second node; a third switch having one end connected to the first node and the other end connected to GND; a fourth switch having one end connected to the second node and the other end connected to the GND; a water resistance measuring unit having the first electrode connected to the first node and the second electrode connected to the second node; The water treatment device according to claim 1 or 2, wherein the voltage measurement terminals include a first terminal connected to the first node and a second terminal connected to the second node.

4. The water treatment device according to claim 3 , wherein the control unit measures the conductivity by measuring a voltage across either the first terminal or the second terminal.

5. The water treatment device of claim 1 , wherein the conductivity sensor is installed upstream of the electrolytic cell.

6. The water treatment device according to claim 1 , wherein the conductivity sensor is installed downstream of the electrolytic cell.

7. The water treatment device according to claim 1 , wherein the conductivity sensor is installed inside the electrolytic cell.

8. an electrolysis power source that applies the voltage to the anode and the cathode of the electrolytic cell under control of the control unit; The water treatment device according to claim 1 , further comprising an insulating unit for insulating the electrolysis power supply from the first conductivity measuring unit and the second conductivity measuring unit.

9. 9. The water treatment device according to claim 8, wherein the insulating unit is provided between the control unit and the electrolysis power supply at a position that insulates a power supply signal line and a power supply GND line that are connected to the control unit and the electrolysis power supply.

10. The water treatment device according to claim 8, wherein the insulating unit is provided between the control unit and the first conductivity measuring unit and the second conductivity measuring unit, at a position that insulates the conductivity sensor signal line and the conductivity sensor GND line connected to the control unit and the first conductivity measuring unit and the second conductivity measuring unit.

11. The water treatment device according to claim 8 , wherein the insulating section is formed of a photocoupler.

12. The water treatment device according to claim 8 , wherein the insulating section is configured by an analog signal isolator.

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