JP2010069366A - Device for removing scale in cooling water and method for removing scale using this device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for removing scale in cooling water which is excellent in durability and maintainability. <P>SOLUTION: The device 10 for removing scale in cooling water precipitates and removes scale components in the cooling water supplied to a heat exchange system 11 such as a cooling tower by electrolytic treatment has an electrolytic cell 12 for electrolyzing the cooling water supplied to the heat exchange system to circulate and supply the cooling water to the heat exchange system, a plurality of electrode plates 13a-13d installed in the electrolytic cell, a relay box portion 14 for switching a connection circuit configuration formed by the electrode plates, a power source portion 15 for applying a voltage, set by the relay box portion, between the electrode plates, and an electrolysis control portion 16 for controlling the relay box portion based on a change in power supply voltage of the power source portion in constant current control for supplying a constant current between the electrode plates. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scale removal device for cooling water for precipitating and removing scale components contained in the cooling water in a heat exchange facility in which scale adhesion in a pipe or the like becomes a problem, and scale removal using the scale removal device Regarding the method.

  A cooling water circulation device that circulates cooling water to a heat exchanger such as a cooling tower cools the heat exchanger such as equipment with the cooling water, then cools the warm water by flowing it to the cooling tower, and circulates again to the heat exchanger. It is something to be made.

  In such a cooling water circulation device, insoluble calcium salt or the like adheres to the inner wall of the piping as a scale, which may cause clogging of the piping or a decrease in cooling efficiency, causing microorganisms to propagate in the device. It is not preferable for hygiene. For this reason, it is common to add chemical | medical agents, such as a disinfectant and a scale inhibitor, to cooling water. Also, if the hardness of the cooling water increases due to evaporation of water over time, the scale tends to adhere, so the cooling water hardness is constantly monitored, and when the hardness exceeds the specified value, the cooling water in the cooling tower is replaced. Things are also done.

However, in recent years, the use of chemicals has been restrained from the viewpoint of preventing environmental pollution, and a scale adhesion prevention method using electrolytic treatment has been developed as an alternative. For example, Patent Literature 1 discloses an electrolytic cell for storing cooling water provided in the cooling water circulation path, a pair of electrodes installed in the electrolytic cell, and a voltage for applying a voltage between the pair of electrode plates. There has been proposed a cooling water circulation device including a source and an electrolysis device that performs electrolysis treatment of the cooling water stored in the electrolytic cell by applying a voltage between the pair of electrode plates.
Republished patent WO2006 / 027825

In the conventional scale removal device for cooling water as shown in Patent Document 1, when supplying power to the electrode for electrodeposition treatment, constant current control is performed in order to keep the electrochemical reaction caused by electrolysis such as precipitation reaction constant. Is made. In this type of power supply unit, in order to change the output voltage, AC is once rectified to DC, and switching (ON / OFF processing) is performed at a constant cycle using a semiconductor such as an FET or IGBT, thereby turning ON / OFF time of the semiconductor. The output voltage for generating the rectangular wave is controlled by changing the ratio. That is, automatic control is performed inside the power supply so as to perform constant current control by reducing the voltage when the ion concentration of the cooling water is high and conversely increasing the voltage when the ion concentration is low.
In this way, when the scale in the cooling water increases and the load resistance decreases, a large current flows through the internal semiconductors (mainly switching semiconductors, rectifier circuit chemicons, etc.). In order to give a big stress, the subject that the durability was reduced and the maintenance process including a power supply circuit was needed occurred.
In addition, there is a problem that the amount of scale is reduced, and even when the maximum voltage of the power supply unit is applied, a specified current does not flow and a constant current cannot flow.

The present invention has been made in order to solve the above-described conventional problems. In constant current control for depositing a scale component in cooling water to remove the scale component, stress due to an excessive voltage change load is applied to the power supply unit of the electrode. An object of the present invention is to provide a cooling water scale removing device that does not cause the occurrence of water and has excellent durability and maintainability.
In addition, the present invention is excellent in control operability and durability when depositing the scale component on the electrode surface by passing the water to be treated through an electrolysis apparatus and removing it from the water. Another object of the present invention is to provide a scale removal method using a scale removal device for cooling water that can be stably performed.

(1) The cooling water scale removing apparatus of the present invention, which has been made to solve the above-described conventional problems, is a cooling water that deposits and removes scale components in cooling water supplied to a heat exchange facility such as a cooling tower by electrolytic treatment. A scale removing apparatus, an electrolytic cell that electrolyzes cooling water supplied to the heat exchange facility and circulates and supplies the heat exchange facility, a plurality of electrode plates installed in the electrolytic cell, and the electrode A relay box section for switching a connection circuit configuration formed by the plates, a power supply section for applying a voltage between the electrode plates set by the relay box section, and the constant current control for supplying a constant current between the electrode plates. And an electrolysis control unit that controls the relay box unit based on a change in the power supply voltage of the power supply unit.

(2) In the cooling water scale removing device according to (1), the present invention controls the relay box unit via the electrolysis control unit, and the power source voltage in the constant current control of the power source unit is equal to or higher than a reference value. In this case, the number of energized electrodes is relatively increased, and the number of energized electrodes is decreased when the power supply voltage is less than a reference value.

(3) In the cooling water scale removing device according to (1) or (2), the electrolysis control unit is supplied to the electrolytic cell based on a current value and a voltage value between the electrode plates. It is characterized by detecting the conductivity of the cooling water.

(4) The cooling water scale removing method of the present invention deposits scale components in the cooling water supplied to the heat exchange facility using the cooling water scale removing device according to any one of (1) to (3). A method of removing scale of cooling water to be removed, wherein the circuit configuration of a plurality of electrode plates installed in the electrolytic cell is switched based on a change in power supply voltage during constant current control of the power supply unit. The number of sheets is increased or decreased, and the electrolytic deposition treatment of the scale component in the cooling water flowing in the electrolytic cell is performed.

  According to the present invention, when supplying a constant current between a plurality of electrode plates and performing an electrolysis process, the connection circuit configuration formed by the electrode plates is switched and controlled based on the change in the power supply voltage of the power supply unit. By changing the electrical resistance of the cooling water due to the increase / decrease of the scale in the cooling water, the electrical resistance of the electrode is changed to reduce the occurrence of stress due to an excessive voltage change in the power supply, thereby improving durability and maintenance. It is possible to provide a scale removal device for cooling water that is excellent in performance and stability of operation of the device.

  The scale removal apparatus for cooling water according to the present embodiment includes an electrolytic cell that electrolyzes cooling water supplied to a heat exchange facility and circulates the heat water to the heat exchange facility, and a plurality of electrodes installed in the electrolytic cell A constant current is supplied between the electrode plate, a relay box portion for switching a connection circuit configuration formed by the plate, the power supply portion for applying a voltage between the electrode plates set by the relay box portion And an electrolysis control unit that controls the relay box unit based on a change in the power supply voltage of the power supply unit in constant current control. Thus, in constant current control for removing the scale, stress due to excessive voltage change is not generated in the power supply portion of the electrode, and the durability of the circuit configuration including the power supply portion can be improved.

  In this way, minerals such as calcium ions and magnesium ions that are contained in the cooling water and cause scales are deposited as scales on the electrode plate set by the relay box during the electrolytic treatment, and the mineral content from the cooling water. Can be removed to reduce the adhesion of scale in the circulation path. Furthermore, by such electrolytic treatment, hypochlorous acid and the like having sterilizing ability can be generated in the cooling water, and due to the effect of electrolytic direct sterilization that destroys the cell membrane by the bacteria in the cooling water coming into contact with the electrode. It is possible to prevent the growth of microorganisms without using a chemical solution with a large environmental load. It is also possible to suppress the waste of water resources by minimizing the exchange of cooling water in the circulation path.

  The scale removal device for cooling water is attached to heat exchange equipment such as air conditioners, boilers, refrigerators, cooling heaters, cooling towers, etc., and deposits scale components such as calcium ions contained in the circulating cooling water by electrolytic treatment. And removing the scale component from the cooling water.

  The electrolytic bath is, for example, a container body that includes a supply port to which cooling water is supplied from a heat exchange facility and a discharge port for electrolyzed cooling water, and electrolyzes the cooling water supplied to the heat exchange facility. In such an electrolytic cell, for example, 2, 3, 4, 5, 6, 7... Electrode plates are arranged in parallel with each other, and a diaphragm plate is arranged between the electrode plates as necessary, so that the electrolytic cell. It can also be formed into a shape.

  Although there is no restriction | limiting in particular regarding the electrode material of an electrode plate, For example, what coated platinum in titanium and the thing which does not elute the component to cooling water, such as carbon, can be used. Moreover, what formed the platinum plating layer on the base-material surface, such as titanium and copper, and the thing which provided the composite plating layer of platinum and iridium, etc. are applicable. By covering the surface of platinum with a noble metal such as iridium, the catalytic action promotes the electrochemical reaction and reduces electrode elution due to anodic oxidation, thereby suppressing electrode consumption.

  The relay box unit is a relay device that incorporates a solid state relay that turns on and off a large output voltage with low power input using a semiconductor element such as a thyristor, and a program relay that is packaged by combining multiple relays. And it is connected to each electrode plate in an electrolytic cell, and the power supply part for supplying electric power to each of these electrode plates, respectively. Thus, the connection circuit configuration set between the power supply unit and each electrode plate is changed to a predetermined pattern (for example, A function of switching to a series circuit configuration and a parallel circuit configuration of electrode plates).

  The power supply unit is a device for applying a voltage between the electrode plates selected and set by the relay box unit. For example, if the DC voltage before switching is 60V, the 0N time is 50%, and the OFF time is 50%, then the output will be 30V by performing rectification (integration processing) on the rectangular wave, and it will turn on in the same way When the time is 10% and the OFF time is 90%, the output voltage is set to 6V. Thus, the output voltage can be controlled by changing the ON / OFF time ratio of the semiconductor.

  The electrolysis control unit is a control board equipped with a CPU, and a sensor for detecting a change in the power supply voltage of the power supply unit is connected via the interface board, and a constant current is supplied between the electrode plates. The relay box unit is controlled based on a change in the power supply voltage of the power supply unit in the constant current control to be supplied. This has a function of reducing the load on the power supply unit in constant current control by selecting a circuit configuration with a plurality of electrode plates loaded with voltage.

The cooling water scale removing apparatus of the present embodiment controls the relay box part via the electrolysis control part, and determines the number of energized electrodes when the power supply voltage in the constant current control of the power supply part is equal to or higher than a reference value. The number of energization electrodes can be decreased when the power supply voltage is less than a reference value. Accordingly, for example, by switching between the series connection state and the parallel connection state of the electrodes to be energized as shown in the figure, the electrical resistance viewed from the power source is 9 times or 1/9 even though the conductivity of the cooling water to be processed is the same. Therefore, it is possible to cope with a larger change in conductivity.
The number of energized electrodes can be changed from 2 (in series) to 4 (in parallel) by switching the circuit configuration of the electrode plates in the electrolytic cell by controlling the relay box unit via, for example, an electrolysis controller. Or it can change suitably from 4 sheets to 8 sheets.

In the cooling water scale removing apparatus of the present embodiment, the electrolysis control unit detects the conductivity of the cooling water supplied to the electrolytic cell based on the current value, the voltage value, and the water temperature between the electrode plates. You can also. By adopting such a configuration, it is possible to monitor the scale concentration, hardness, etc. of the cooling water on the basis of the energization data of the electrode in the cooling water scale removing device without providing a conductivity meter separately. In addition, it is possible to provide a use environment with excellent maintainability and cost.
The electrolysis control unit is connected to a sensor for acquiring a voltage value, a current value, and a water temperature value between the electrode plates through an interface, and the storage unit serving as the database has an experimentally obtained space between the electrode plates. Control data of current value, voltage value, water temperature value, and corresponding conductivity of the cooling water is held. Based on the conductivity of the cooling water thus obtained, constant current control corresponding to a state where the ion concentration of the cooling water is high and a state where it is low may be performed.

  The cooling water scale removal method of the present embodiment is a cooling water scale removal method for depositing and removing scale components in cooling water supplied to the heat exchange equipment using a cooling water scale removal device, the power supply Based on the change in the power supply voltage during constant current control of the unit, the circuit configuration of the plurality of electrode plates installed in the electrolytic cell is switched to increase or decrease the number of energized electrodes, and the cooling water flowing in the electrolytic cell Electrolytic deposition treatment of the scale component is performed. Thereby, since the connection circuit configuration formed by the electrode plate is switched based on the change in the power supply voltage of the power supply unit, the constant current control does not cause stress due to an excessive voltage change load on the power supply unit of the electrode, It is possible to provide a cooling water scale removing device having excellent durability and maintainability. In other words, stable current is generated without stopping the output so that a large current flows through the semiconductor in the power supply section (mainly switching semiconductor, chemicon of rectifier circuit, etc.) and the power supply itself performs self-defense. Processing is maintained. Further, by switching between the series and parallel of the electrodes, the electrical resistance viewed from the power source can be adjusted, so that it is possible to cope with a larger change in conductivity.

Example 1
FIG. 1 is a schematic diagram of a scale removal device for cooling water according to a first embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described in detail below with reference to the drawings.
The cooling water scale removing device 10 according to the first embodiment is for electrolyzing cooling water circulated in a heat exchange facility 11 or the like provided in an air conditioner, a refrigerator, or the like. An electrolytic bath 12 for electrolytically treating the cooling water and circulatingly supplying it to the heat exchange facility 11, four electrode plates 13a to 13d installed in the electrolytic bath 12, and connecting to the electrode plates 13a to 13d A relay box section 14 for switching the connection circuit configuration, a power supply section 15 for applying a voltage to the electrode plates 13a to 13d set by the relay box section 14, and a prescribed constant current between the electrode plates 13a to 13d. An electrolysis control unit 16 for controlling the operation of the relay box unit 14 based on a change in the power supply voltage of the power supply unit 15 in the constant current control to be supplied.

  The heat exchange facility 11 has a cooling water tank 11a for holding a predetermined amount of cooling water. Further, a circulation pump 21 is provided for supplying an appropriate amount of cooling water to the heat exchange facility 11, and a scale removal device circulation pump 11 b for circulating supply of cooling water to the scale removal device 10 is provided. Yes. Note that a water passage that passes from the electrolytic cell 12 of the scale removing device 10 and returns to the cooling tank 11a, a supply water channel that supplies the electrolytic cell 12, and a discharge channel that discharges the cooling water stored at the bottom of the electrolytic cell 12 are respectively provided. Control systems such as flow control valves 17 and 18 are provided, and the circulation pump 11b and the flow control valves 17 and 18 are driven and controlled via the electrolysis control unit 16, respectively.

  In this way, the cooling water circulation passage for circulating the cooling water is connected to the heat exchange facility 11 such as a cooling tower, and the whole is configured in a loop shape. The cooling tower has a general configuration in which water is cooled by contact with air. A circulating pump (not shown) is provided on the outgoing water pipe so that the cooling water cooled by the cooling tower can be pumped. In addition, since the cooling water flowing through the circulation channel is lost due to evaporation or maintenance over time, the cooling tower is provided with a supply pipe for supplying the cooling water from the outside.

  The scale removal apparatus 10 for cooling water is provided with first to fourth electrode plates 13a to 13d inside an electrolytic bath 12 for electrolytically treating the cooling water. These electrode plates 13 a to 13 d are connected to the power supply unit 15 via the relay box unit 14. The electrode plates 13a to 13d are not particularly limited as long as they are normally used in an electrolysis apparatus. For example, titanium or copper coated with platinum, carbon electrodes, or the like can be preferably used. An electrolysis control unit 16 that functions as a controller is connected to the power supply unit 15 that generates direct current to control the voltage applied to the electrode plates 13a to 13d, and to monitor the current and voltage between the electrode plates. You can also do it.

  A water supply pipe 12a for supplying circulating water from the cooling water tank 11a and an outflow pipe 12b for returning to the cooling water tank 11a are connected to the electrolytic tank 12, and a cooling water circulation flow for performing electrolytic treatment A road is constructed. A removal device circulation pump 11b is provided on the side of the water supply pipe 12a so that the cooling water in the cooling water tank 11a can be pumped to the electrolytic cell 12. The cooling water flowing out from the electrolytic cell 12 is returned to the cooling water tank 11a through the outflow pipe 12b. In addition, a discharge pipe 12c is provided at the bottom of the electrolytic cell 12, so that the cooling water including the scale portion retained in the electrolytic cell is discharged through the flow rate control valve 18 to the outside of the cooling circulation channel. It has become.

  A flow meter 19 and a thermometer sensor 20 are attached to predetermined locations in the coolant circulation path on the water supply pipe 12a side. As described above, the flow rate and temperature data of the cooling water supplied to the electrolytic cell 12 are taken into the electrolysis control unit 16 and the energization state of the scale removing device 10 is determined together with the electrolysis data such as the electrolysis voltage and the electrolysis current in the electrolytic cell 12. Thus, the electrode plate connection configuration can be set to a predetermined pattern or the electrolysis conditions such as the electrolysis voltage can be changed according to the determination result.

Next, a cooling water scale removing method applied to the cooling water scale removing apparatus 10 according to the first embodiment configured as described above will be described.
The power supply unit 15 for supplying DC power to the electrode plates 13a to 13d uses, for example, a constant current specification electrolytic DC power supply having a maximum of 60V / constant current of 10A. This type of power supply, which is generally sold at present, rectifies the input AC once to change the output voltage, and performs switching (ON / OFF processing) at regular intervals using semiconductors such as FET and IGBT. To generate a square wave. For example, when the DC voltage before switching is 60 V, the 0N time is 50%, and the OFF time is 50%, the output is about 30 V by performing rectification (integration processing) on the rectangular wave thereafter. .

  Similarly, when the ON time is 10% and the OFF time is 90%, the output voltage is set to 6V. In this way, the output voltage is controlled by changing the ON / OFF time ratio of the semiconductor. When constant current control is performed using such a power supply, when the current flows (when the concentration of circulating water such as the ion concentration is high), the current easily flows and the voltage is automatically controlled inside the power supply. I do. For example, if it is set to control at 10 A, when the ON time is 10% and the OFF time is 90%, the current that flows when the semiconductor is turned on becomes 100 A or more. (Several times more current flows at the moment when the power is turned on.) When the power output is as described above, the load resistance becomes small even with a power supply of 60 V maximum and 10 A. Internal semiconductors (mainly switching semiconductors, rectifier circuits, etc.) A large current flows through the chemi-con, etc.), giving a large stress to each component of the power circuit. For this reason, the minimum voltage during operation of the DC power supply is set for the reasons described above. Some power supplies stop the output so that the power supply itself performs self-defense.

  In addition, the scale removal apparatus 10 for cooling water drives the relay box part 14 via the electrolysis control part 16, and switches the arrangement state of each electrode plate 13a-13d to serial, parallel, etc. as shown in FIG. Can do. As a result, even if the conductivity of the cooling water flowing through the cooling water circulation channel is the same, a parallel connection in which a voltage is applied to each of the four electrodes 13a to 13d from a series connection in which a voltage is applied between the two electrodes 13a and 13d. By switching to the connection, the electric resistance viewed from the power source can be increased to about 9 times or 1/9, and a larger change in conductivity can be dealt with. 60V is the maximum value of the control voltage of the switching element in the power supply, and the current flowing to each electrode is limited to 10A.

  FIG. 3 is an explanatory diagram showing an example of a control method for switching the circuit configuration of the electrode plates 13a to 13d by controlling the relay box unit 14 based on a voltage (power supply voltage) measured in the power source unit 15. As shown in the figure, in the first step S1, by operating a start button or the like provided on the operation panel of the cooling water scale removing device 10, the circulating pump 11b of the cooling water scale removing device 10 starts its operation. Then, the cooling water in the cooling water tank 11 a is circulated and supplied to the electrolytic cell 12.

  In the next step S2, a series connection state (energization state) in which a voltage is applied to the two electrode plates 13a and 13d in the electrolytic cell 12 via the relay box portion 14 is set, and the electrolytic treatment is performed. The

  In step S3, the voltage in the power supply unit 15 is measured after elapse of a predetermined time, for example, about 30 seconds, through the electrolysis control unit 16, and it is determined whether the measured voltage value is 60 volts or more and less than 60 volts. . If the voltage value is less than 60 volts, the process proceeds to step S4 where the series connection is continued, and if it is 60 volts or more, the process proceeds to step S5.

  In step S5 when the voltage value is 60 volts or more, a parallel connection state in which voltage is applied to all four electrode plates 13d to 13d in the electrolytic cell 12 via the relay box unit 14 and the electrolysis control unit 16 ( Switch to energized state.

  In step S6 following step S5, the voltage in the power supply unit 15 is measured again to determine whether the measured voltage value is 20 volts or more or less than 20 volts. If the voltage value is 20 volts or more, the process proceeds to step S7 where the parallel connection is continued, and if it is less than 20 volts, the process proceeds to step S2.

  In the constant current control for supplying a constant current between the plurality of electrode plates, the relay box unit 14 is controlled based on the change in the power supply voltage of the power supply unit 15 by executing the series of processes in steps S1 to S7 described above. Therefore, the scale component in the cooling water supplied to the heat exchange facility 11 can be stably deposited and removed by electrolytic treatment. Furthermore, in constant current control to remove scale, the scale of the cooling water has excellent durability and control operability in the electrodeposition process without causing stress due to an excessive voltage change load on the power supply part of the electrode. A removal method can be provided.

  FIG. 4 shows the respective electrolysis voltages and electrolysis in the series connection (using two energized electrode plates) and the parallel connection (using four energized electrode plates) of the electrode plates 13a to 13d measured in Example 1. It is a graph which shows an example of the relationship with the resistance value of the tank 12, and Table 1 shows the data table of each voltage and the resistance value of the electrolytic cell 12 which were measured and calculated corresponding to the series connection and parallel connection. Yes. Here, the electrolytic current is operated in a range of approximately 20 to 60 volts as a constant current control condition for operating at a constant current.

  Since the electrical conductivity (reciprocal of the resistance value) of the electrolytic cell 12 and the scale in the cooling water have a predetermined proportional relationship, the circuit configurations of the electrode plates 13d to 13d in the electrolytic cell 12 are compared as shown in FIG. An operation of switching to serial connection when the electrical conductivity of the general cooling water is high and switching to parallel connection when the electrical conductivity is low can be adopted based on the change in the voltage.

  As described above, in the present invention, when a constant current is supplied between a plurality of electrode plates to electrolyze cooling water, the connection formed by the electrode plates is based on the change in the power supply voltage of the power supply unit. The gist of switching and controlling the circuit configuration is that which falls under the scope of the present invention. For example, in the present embodiment, the case where the number of electrode plates arranged in parallel in the electrolytic cell 12 is four is described in detail, but two or more electrode plates are arranged in parallel in the electrolytic cell, Electrode plates that are connected to the relay box and activated in the electrolytic cell based on the electrolysis voltage and current measured in the electrolytic cell, the conductivity, temperature, flow rate, etc. of the cooling water flowing in the cell The electrolysis conditions such as the circuit pattern and the applied voltage may be set.

It is the schematic of the scale removal apparatus of the cooling water which concerns on Example 1. FIG. It is explanatory drawing which shows the switching state of each electrode plate in an electrolytic vessel. It is explanatory drawing of the control method which switches the circuit structure of an electrode plate. It is a graph which shows the relationship between the electrolysis voltage in each connection state of an electrode plate, and electrolytic cell resistance value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cooling water scale removal apparatus 11 Heat exchange equipment 11a Cooling water tank 11b Circulation pump for removal apparatus 12 Electrolyzer 12a Water supply pipe 12b Outflow pipe 12c Discharge pipe 13a-13d Electrode plate 14 Relay box part 15 Power supply part 16 Electrolysis control part 17 , 18 Flow control 19 Flow meter 20 Water temperature meter 21 Circulating water pump

Claims (4)

A cooling water scale removing device that precipitates and removes scale components in cooling water supplied to a heat exchange facility such as a cooling tower by electrolytic treatment,
An electrolytic cell that electrolyzes cooling water supplied to the heat exchange facility and circulates and supplies it to the heat exchange facility, a plurality of electrode plates installed in the electrolytic cell, and a connection circuit formed by the electrode plates Relay box section for switching the configuration, power supply section for applying a voltage between electrode plates set by the relay box section, and change in power supply voltage of the power supply section in constant current control for supplying a constant current between the electrode plates And an electrolysis control unit for controlling the relay box unit based on the above.   The relay box part is controlled via the electrolysis control part, and the power supply voltage in the constant current control of the power supply part is relatively increased when the power supply voltage is equal to or higher than a reference value. 2. The cooling water scale removing device according to claim 1, wherein the number of the energizing electrodes is reduced when the number is less than the number.   The scale of the cooling water according to claim 1 or 2, wherein the electrolysis control unit detects a conductivity of the cooling water supplied to the electrolytic cell based on a current value and a voltage value between the electrode plates. Removal device.   A scale removal method for cooling water that deposits and removes scale components in the cooling water supplied to the heat exchange facility using the scale removal device for cooling water according to any one of claims 1 to 3, comprising: Based on the change in the power supply voltage during constant current control, the circuit configuration of the plurality of electrode plates installed in the electrolytic cell is switched to increase or decrease the number of energized electrodes, and the scale in the cooling water flowing in the electrolytic cell A method for removing scale of cooling water, comprising performing electrolytic deposition treatment of components.

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