JP4943880B2 - Cooling water supply / drainage method for cooling tower and cooling water supply / drainage method for cooling tower group using the same - Google Patents

Description

  The present invention relates to a cooling water supply / drainage structure in a cooling tower and a cooling water supply / drainage structure in a cooling tower group in which a plurality of open type cooling towers are connected. This relates to the cooling water supply / drainage structure of the cooling tower group.

  FIG. 3 is a schematic diagram of a cooling water supply / drainage structure of a conventional cooling tower group.

  As illustrated, the cooling tower group 101 is formed by arranging a plurality of open cooling towers 102 in parallel. Each cooling tower 102 includes a water storage tank 103 and a cooling tower main body 104 that covers the water storage tank 103. The water storage tank 103 is connected to the refrigerator 105 by an outgoing pipe 106 and a return pipe 107. The forward piping 106 is provided with a pump 121 for feeding the cooling water in the water storage tank 103 to the refrigerator 105. The return pipe 107 is connected to a cooling water sprinkling pipe 108 provided in the upper part of the cooling tower body 104. A fan 109 for cooling the cooling water sprayed from the cooling water sprinkling pipe 108 is provided in the upper part of the cooling tower main body 104.

  The water storage tank 103 is provided with an overflow pipe 110 for draining the cooling water in the water storage tank 103. An overflow pipe 110 provided in the water storage tank 103 of each cooling tower 102 is connected to a common drain pipe 111. The bottom of the water storage tank 103 is provided with a cleaning drain pipe 113 that is opened and closed by a valve 112 for draining the cooling water when cleaning the water storage tank 103 or the like.

  A blow device 114 for measuring the conductivity of the cooling water in the water storage tank 103 is connected to the water storage tank 103 via a sensor 115. The blow device 114 adjusts the opening degree of the electric valve 117 provided in the water supply pipe 116. The water storage tank 103 is provided with a ball tap 119 attached to a water supply pipe 118 provided separately from the water supply pipe 116 described above. The water supply pipes 116 and 118 provided in the water storage tank 103 of each cooling tower 102 are connected to the common water supply pipe 120.

  In such a cooling tower group 101, the cooling water used in each refrigerator 105 passes through the cooling water sprinkling pipe 108 from the return pipe 107, is cooled in the cooling tower body 104 by the fan 109, and is stored in the water storage tank 103. It is done. At this time, the amount of water in the cooling water in the water storage tank 103 decreases due to evaporation or the like during cooling in the cooling tower body 104. For this reason, the cooling water is concentrated and the conductivity is increased. When the conductivity increases, ions in the water gradually crystallize and precipitate, resulting in scaling. If the scaled cooling water is allowed to stand, the cooling tower 102 is corroded and the cooling efficiency by the refrigerator 105 is reduced.

  Therefore, in order to lower the electrical conductivity of the cooling water in the water storage tank 103, the cooling water having a higher electrical conductivity is drained from the water storage tank 103, and new makeup water is supplied to the water storage tank 103.

  For water supply to the water storage tank 103, the electric conductivity of the cooling water in the water storage tank 103 is measured by the blow device 114 via the sensor 115. If the electric conductivity is higher than the predetermined electric conductivity, the electric valve 117 is opened and the water supply pipe 116 is opened. Supply water is supplied to the water storage tank 103. Further, when the water level in the water storage tank 103 decreases and falls below the predetermined water level, the ball tap 119 is opened, and new makeup water is supplied from the water supply pipe 118. Drainage from the water storage tank 103 is raised by the water supply from the water supply pipes 116 and 118 described above, the water level in the water storage tank 103 is raised, and overflowed by the overflow pipe 110 to be drained.

  By such an action, new supply water is continuously supplied from the water supply pipe 116 or 118 until the cooling water in the water storage tank 103 reaches a predetermined conductivity or a predetermined water level.

  However, in the cooling water supply / drainage structure of the conventional cooling tower group described above, water supply from the water supply pipes 116 and 118 is performed from above the water storage tank 103, and the drain outlet of the overflow pipe 110 is also above the water storage tank 103. For this reason, the drained cooling water contains a lot of new supplied water. Therefore, the replacement efficiency of the cooling water is poor, and therefore unnecessary water supply is performed. Furthermore, although dust such as sand dust and foreign matters such as dead leaves are accumulated in the lower part of the water storage tank 103 of the open type cooling tower 102, it is difficult to directly discharge them with the overflow pipe 110. Moreover, since it is necessary to install the blow apparatus 114 and the ball tap 119 for each cooling tower, the apparatus becomes complicated and a large equipment cost is required.

  Patent Document 1 discloses a cooling tower water supply / drainage control device adopting such a configuration. The water supply / drainage structure described in Patent Document 1 also drains from the upper part of the water storage tank by overflow, and has a water supply means for each cooling tower, and has the same problems.

  FIG. 4 is a schematic view of another conventional cooling tower water supply / drainage structure.

  FIG. 4 shows another cooling tower as an example of the cooling tower 102 shown in FIG. As illustrated, the blow device 114 is connected to the electric valve 122 of the drain pipe 113 connected to the bottom surface of the water storage tank 103. When the electrical conductivity of the cooling water in the water storage tank 103 is equal to or higher than a predetermined value, the blow device 114 opens the electric valve 122 and drains the cooling water below the water storage tank 103. When the cooling water is drained, the water level decreases, so that makeup water is supplied from the water supply pipe 118 of the ball tap 119. Alternatively, the valve 123 is manually opened to supply water from the water supply pipe 116. As such a configuration, new makeup water is supplied from above the water tank, and the cooling water at the bottom of the water tank 103 with high conductivity is drained from the bottom surface of the water tank 103 to improve the efficiency of replacing the cooling water. I was trying to let them.

  However, in the conventional cooling tower drainage structure described above, the opening and closing operation of the electric valve 122 is performed according to the conductivity and water level of the cooling water in the water storage tank 103. As described above, the cooling water in the water storage tank 103 of the open type cooling tower 102 may be mixed with dust such as sand dust or foreign matter such as dead leaves. There is a high possibility that a malfunction will occur.

  Patent Document 2 discloses a cooling tower water supply method and apparatus employing such a configuration. The drainage structure of the cooling tower described in Patent Document 2 also discharges cooling water together with the earth and sand from the lower part of the water storage tank, and the drain pipe is opened and closed by a valve. Have similar problems.

  FIG. 5 is a schematic view of another conventional cooling tower group water supply / drainage structure.

  As shown, the forward piping 106 and the return piping 107 of each cooling tower 102 are connected by common headers 124 and 125, respectively. In this way, the common headers 124 and 125 are provided, and each cooling tower 102 is not individually controlled, but the cooling tower group 101 including a plurality of cooling towers 102 is collectively controlled. Accordingly, the forward and return cooling water used in the refrigerator 105 is shared by the common headers 124 and 125, and the cooling water conductivity between the cooling towers 102 is made uniform and collectively managed as the cooling tower group 101. Is.

  Further, the water storage tanks 103 are connected to each other by a communication pipe 126. As a result, the conductivity of the cooling water between the water storage tanks 103 is further made uniform, and the water level of the cooling water between the water storage tanks 103 is made uniform. Other configurations are the same as those in FIG.

  However, the above-described water supply / drainage structure of the cooling tower group is also a drainage structure using the overflow pipe 110, and the replacement efficiency cannot be improved. Further, it is necessary to provide the blow device 114 in each water storage tank 103, and it is necessary to dispose a ball tap 119 for each water storage tank 103 in order to measure the water level.

JP 2005-61680 A Japanese Patent Laid-Open No. 9-138094 JP-A-7-91878

  Patent Document 3 discloses a water level control method and a water level control device for a cooling tower water tank using a common header. The control of the water level is not to make the water level in each cooling tower uniform using a communication pipe, but to indicate the water level obtained by calculation from parameters such as the number of operating units on the water level meter on the assumption that the water level is different. In other words, in order to keep the difference in the number of water passing through the cooling tower between each block within the allowable limit, select a cooling tower that passes water, and set the water level with a water gauge that has the same water level as the water tank of the block with the same water passing base. Is to adjust the amount of water to be supplied by a control valve, etc., in order to change it according to the total number of water passing through the cooling tower, and to change the setting value of the water level gauge attached to the cooling water outlet header according to the number of water passing through It is. Such control is complicated in calculation method, complicated in its mechanism, and complicated as a whole control method. Patent Document 3 does not specify a mechanism for drainage.

  The present invention takes the above-mentioned conventional technology into consideration, has a simple structure, can improve the replacement efficiency of the cooling water in the water storage tank of the cooling tower, and can save the makeup water. Providing a cooling water supply / drainage structure for a cooling tower that can be managed in a batch and a cooling water supply / drainage structure for a cooling tower group using the same without the need to install equipment for measuring the conductivity and water level of the cooling water It is intended.

To achieve the above object, according to the first aspect of the present invention, there is provided a cooling tower for cooling the cooling water supplied to the refrigerator, a water tank provided at the lower part of the cooling tower for storing the cooling water, and the water tank. A drainage pipe for draining the cooling water from, and a water supply pipe for supplying the cooling water makeup water from the upper side of the water storage tank, the drainage pipe is composed of a rising part and a lowering part, An end portion of the rising portion is provided with a drain port disposed at a lower portion of the water storage tank, and an end portion of the lowering portion is provided with a discharge port disposed outside the water storage tank. The lower part and the lower part are connected at a position higher than the drain outlet and at a position lower than the side wall height of the water storage tank, an upper end of the lower part is provided with an opening, and the water supply pipe enters the water storage tank. Supply water is replenished, and the water level of the water tank rises At the same time the water level in the rising part rises, and when the water in the rising part exceeds the height of the connecting part, it flows through the connecting part to the falling part and drains from the drain outlet of the falling part. A cooling water supply / drainage method for a cooling tower is provided.

  According to a second aspect of the present invention, in the first aspect of the present invention, the drain port is formed on a bottom surface or a lower side surface of the water storage tank.

The invention of claim 3 is applied to a cooling tower group in which a plurality of the cooling towers of the invention of claim 1 or 2 are arranged, and is provided in the upper part of the cooling tower and serves as a water supply pipe. The return common header includes a water pipe, a return pipe and return pipe for cooling water disposed between the cooling tower and the refrigerator, and a return common header for communicating the return pipes of the plurality of cooling towers. A control device for measuring the electrical conductivity of the cooling water in the interior, a supplementary water supply pipe communicating with the return common header, an electric valve in the supplementary water supply pipe, and based on the electrical conductivity measurement result of the control device And a cooling water supply / drainage method for a cooling tower group, wherein the water supply amount to the return common head is adjusted by the electric valve .

Further, in the invention of claim 4, in the invention of claim 3 , the water storage tanks of the plurality of cooling towers are provided with a communication pipe for communicating the water storage tanks, and the water level in the water storage tank is connected to the communication pipe. A cooling water supply / drainage method for a cooling tower group is provided , wherein a water level meter for measuring the temperature is disposed, and the control device adjusts an opening degree of the electric valve based on a measurement result of the water level meter. To do .

According to the first aspect of the present invention, since the drain pipe composed of the rising part and the falling part is used to drain the cooling water from the water tank, the cooling water in the water tank enters the rising part from the drain port. However, as the cooling water level in the water storage tank rises, it can rise in the rising portion and be discharged from the drain outlet provided in the falling portion. Since the drain port provided in the rising portion is disposed at the lower part of the water storage tank, the cooling water can be drained from the lower part of the water storage tank when makeup water is supplied from the upper side of the water storage tank. Therefore, it is possible to prevent the new makeup water supplied from the upper side of the water tank from being drained immediately, and to improve the replacement efficiency of the cooling water whose conductivity has been increased by use and the new makeup water. , Useless water supply can be suppressed. In addition, the upper end of the falling part is provided with an opening to prevent siphoning in the drainage pipe, so that the siphoning phenomenon occurs when the outlet of the lowering part is lower than the outlet of the rising part. It is possible to prevent the cooling water in the water storage tank from being continuously drained.

  According to the invention of claim 2, since the drainage port is formed on the bottom surface or the lower side surface of the water storage tank, dust such as dust collected at the bottom of the water storage tank and foreign matter such as dead leaves can be easily removed from the drainage port. Can be discharged. Since this discharge is performed using a drain pipe composed of a rising part and a falling part, a valve is not required for the drain pipe. For this reason, dust and foreign matter are not bitten by the valve, and the valve does not malfunction.

Further, according to the invention of claim 3 , since the control device for measuring the conductivity is provided in the return common header connected to the return pipe to each cooling tower, the conductivity is provided in the water tank provided in each cooling tower. It is not necessary to provide a device for measuring the above. For this reason, an apparatus is simplified and a huge installation expense is not required. In addition, from the measurement result by this control device, the return common header is used to adjust the amount of makeup water from the makeup water supply pipe by the electric valve, so the conductivity of the cooling water in the cooling tower group is managed collectively. Can do.

According to the invention of claim 4 , the water level of each water tank can be made uniform by the communication pipe. Therefore, the water level of each water tank can be grasped by providing a water level meter in the communication pipe. For this reason, it is not necessary to provide a water level gauge or ball tap in each water tank, and the water level of each water tank is measured with a simple structure, and the water level is controlled by adjusting the electric valve provided in the makeup water supply pipe. Can do. Therefore, no complicated calculation or control method is required for valve control.

The present invention includes a cooling tower for cooling cooling water supplied to a refrigerator, a water storage tank provided in a lower part of the cooling tower for storing the cooling water, and drainage for draining the cooling water from the water storage tank. A pipe and a water supply pipe for supplying makeup water for the cooling water from the upper side of the water tank,
The drain pipe is constituted by a rising portion and a falling portion, and an end portion of the rising portion is provided with a drain outlet disposed at a lower portion of the water storage tank, and the water storage tank is provided at an end portion of the falling portion. The outlet and the lowering portion are connected to each other at a position higher than the drainage port and lower than the height of the side wall of the water storage tank, and are connected to an upper end of the lowering portion. Is provided with an opening, replenishing makeup water into the reservoir from the water supply pipe, the water level in the rising portion rises at the same time as the water level of the reservoir rises, and the water in the rising portion rises to the height of the connecting portion. If it exceeds, it will flow to the descending part through the connecting part and drain from the drain part of the descending part, and with a simple structure, the efficiency of replacing cooling water in the water tank of the cooling tower is improved and replenished Can save water To install equipment for measuring the conductivity and the water level of the cooling water in each cooling tower becomes unnecessary, the cooling water supply and discharge method and cooling tower group using the same cooling tower which enables managed together plumbing Is the method .

  FIG. 1 is a schematic sectional view of a cooling water supply / drainage structure of a cooling tower according to the present invention.

  As shown in the drawing, the cooling tower 2 includes a water storage tank 3 in which cooling water is stored and a cooling tower body 4 that covers the water tank 3 from above. The cooling tower body 4 includes a cooling water sprinkling pipe 8 to which cooling water returned from the refrigerator 5 (see FIG. 2) is supplied, and a fan 9 and a filler 10 for cooling the cooling water. A louver 11 is disposed outside the filler 10. The cooled cooling water is stored in the water storage tank 3. The accumulated cooling water is sent from the forward piping 6 (see FIG. 2) connected to the water storage tank 3 to the refrigerator 5 (see FIG. 2).

  The water storage tank 3 is provided with a drain pipe 27. The drain pipe 27 includes a rising pipe 28 that is a rising part, a falling pipe 29 that is a falling part, and a connecting pipe 30 that connects them. A lead-in pipe 31 is connected to the riser pipe 28, and a drain port 32 is opened at an end thereof. The rising pipe 28 is connected to a cleaning drain pipe 13 that is opened and closed by a valve 12 for draining the cooling water during cleaning of the water storage tank 3 or the like. The cleaning drain pipe 13 may be provided directly connected to the bottom of the water storage tank 3.

  The riser pipe 28 is disposed so that the upper end portion thereof is located above the drain port 32 and is lower than the side wall height of the water storage tank 3. The downcomer 29 has a discharge port 33 at its end, and this discharge port 33 is arranged outside the water storage tank 3. The end of the downcomer 29 opposite to the discharge port 33 is disposed above the discharge port 33 and at a position lower than the side wall height of the water storage tank 3. Thereby, the siphon phenomenon can be prevented as will be described later. The connecting pipe 30 connects the upper ends of the rising pipe 28 and the lowering pipe 29 substantially horizontally to each other at a position lower than the side wall height of the water storage tank 3.

  Water supply to the cooling tower 2 is performed from the cooling water sprinkling pipe 8 as described later. That is, the cooling water sprinkling pipe 8 is supplied with cooling water from the refrigerator 5 (see FIG. 2) and new makeup water. Therefore, the cooling water sprinkling pipe 8 is a water supply pipe in the present invention.

  In such a structure, water supply / drainage in the cooling tower 2 is performed as follows. When the conductivity of the cooling water in the water storage tank 3 is increased or the water level is lowered (that is, the water level is lowered to the water supply start water level S), makeup water is supplied from the cooling water sprinkling pipe 8. Thereby, the water level in the water storage tank 3 rises. Along with this, the water level in the riser 28 also rises. When the electrical conductivity is high, water is supplied to a height exceeding the overflow water level U. Therefore, since the water level in the rising pipe 28 reaches the connecting pipe 30, the cooling water passes through the connecting pipe 30, passes through the descending pipe 29, and is discharged from the discharge port 33. When the electrical conductivity is within a predetermined value and the water level is simply low, the water is supplied up to the water supply end water level T.

  Since the drain port 32 is disposed in the lower part of the water storage tank 3, even if makeup water is supplied from the upper side of the water storage tank 3, new supplied water is not immediately drained. Therefore, it is possible to improve the efficiency of replacement of the cooling water whose conductivity has been increased by use and the new makeup water, and to suppress useless water supply. That is, it is possible to save water.

  Further, the drain port 32 is formed on the bottom surface (dotted line in the figure) or the lower side surface (solid line in the figure) of the water tank 3, so that dust such as dust collected at the bottom of the water tank 3, dead leaves, etc. The foreign matter can be discharged from the drawing tube 31 by the force of running water. Regarding this discharge, since no valve is formed in the drain pipe 27, dust and foreign matter are not bitten by the valve, and malfunction of the valve does not occur. Whether the drain port 32 is formed on the bottom surface or the lower side surface of the water storage tank 3 can be appropriately selected. Also, large dust that cannot be discharged by the power of running water accumulates on the cleaning drain pipe side and is drained during regular cleaning.

  Moreover, an opening 34 for preventing siphon phenomenon in the drain pipe 27 is provided at the upper end of the down pipe 29. Thereby, when the discharge port 33 of the down pipe 29 is at a position lower than the drain port 32 of the rise pipe 28, it is possible to prevent the siphon phenomenon from occurring and the cooling water in the water storage tank 3 from being continuously drained.

  FIG. 2 is a schematic view of the water supply / drainage structure of the cooling tower group according to the present invention.

  As illustrated, the cooling tower group 1 is formed by arranging a plurality of open cooling towers 2 in parallel. As described above, each cooling tower 2 includes a water tank 3 and a cooling tower body 4 that covers the water tank 3. The water supply / drainage structure using the cooling water sprinkling pipe 8 and the drainage pipe 27 of the cooling tower 2 is the same as the example shown in FIG. The water storage tank 3 is connected to the refrigerator 5 by a forward pipe 6 and a return pipe 7. The forward piping 6 is provided with a pump 21 for feeding the cooling water in the water storage tank 3 to the refrigerator 5. The return pipe 7 is connected to a cooling water sprinkling pipe 8 provided at the upper part of the cooling tower body 4. The outgoing pipe 6 and the return pipe 7 of each cooling tower 2 are connected by an outgoing common header 24 and a return common header 25, respectively.

  A sampling pipe 35 branches from the return common header 25. The sampling pipe 35 is provided with a sensor 15 for measuring the conductivity of the cooling water in the sampling pipe 35. The sensor 15 is connected to the control device 14. Thus, by measuring the electric conductivity of the cooling water in the sampling pipe 35, the electric conductivity of the cooling water supplied to each cooling tower 2 communicating with this can be measured.

  The return common header 25 is provided with a makeup water supply pipe 36 communicating therewith. The makeup water supply pipe 36 is provided with an electric valve 17 for adjusting the amount of water supplied to the return common header 25 based on the measurement result of the control device 14. The electric valve 17 is connected to the control device 14 and the opening degree is adjusted by the control device 14.

  Thereby, when the cooling water is concentrated and the conductivity is increased, this can be measured by the sensor 15, and the electric valve 17 can be opened by the control device 14 to supply makeup water. The makeup water is supplied from the cooling water sprinkling pipe 8 to the water storage tank 3, and the cooling water is drained from the drain pipe 27 as the water level in the water storage tank 3 rises. In this way, the makeup water and the cooling water are switched. When the electrical conductivity of the cooling water in the water storage tank 3 falls to a predetermined value, the control device 14 closes the electric valve 17 and stops the supply of makeup water. Thereby, the electrical conductivity of the cooling water flowing through the cooling tower group 1 can be collectively managed without providing a measuring device for the electrical conductivity in each cooling tower 2.

  The water tanks 3 are connected to each other through a communication pipe 26. The communication pipe 26 is provided with a water level gauge 37. By providing the communication pipes 26, the water levels in the respective water storage tanks 3 are aligned. Therefore, the water level gauge 37 is provided in the communication pipes 26, whereby the water levels of all the water storage tanks 3 can be measured. Therefore, it is not necessary to provide a water level gauge, a ball tap or the like in each water tank 3. The water level gauge 37 is connected to the control device 14. When the water level in each water tank 3 is lowered, the control device 14 opens the electric valve 17 to supply makeup water. Therefore, the water level can be controlled with a simple structure and without requiring a complicated calculation or control method. The water level gauge 37 may not be provided in the connecting pipe 26 but may be provided in any one of the water storage tanks 3.

It is a schematic sectional drawing of the cooling water supply / drainage structure of the cooling tower which concerns on this invention. It is the schematic of the water supply / drainage structure of the cooling tower group which concerns on this invention. It is the schematic of the cooling water supply / drainage structure of the conventional cooling tower group. It is the schematic of the water supply / drainage structure of another conventional cooling tower. It is the schematic of the conventional water supply / drainage structure of another cooling tower group.

Explanation of symbols

1: Cooling tower group, 2: Cooling tower, 3: Water storage tank, 4: Cooling tower body, 5: Refrigerator, 6: Outward piping, 7: Return piping, 8: Cooling water sprinkling pipe, 9: Fan, 10: Filler, 11: louver, 12: valve, 13: drainage pipe for cleaning, 14: controller, 15: sensor, 17: electric valve, 21: pump, 24: forward common header, 25: return common header, 26: Communication pipe, 27: drain pipe, 28: rise pipe, 29: down pipe, 30: connecting pipe, 31: lead-in pipe, 32: drain outlet, 33: discharge outlet, 34: opening, 35: sampling pipe, 36: Makeup water supply pipe, 37: Water level gauge, 101: Cooling tower group, 102: Cooling tower, 103: Water tank, 104: Cooling tower body, 105: Refrigerator, 106: Outward piping, 107: Return piping, 108: Cooling Water sprinkling pipe, 109: Fan, 110: Overflow -Pipe, 111: Common drain pipe, 112: Valve, 113: Cleaning drain pipe, 114: Blow device, 115: Sensor, 116: Water supply pipe, 117: Electric valve, 118: Water supply pipe, 119: Ball tap, 120: Common water supply pipe, 121: pump, 122: electric valve, 123: valve, 124: forward common header, 125: return common header, 126: communication pipe

Claims (4)

A cooling tower for cooling the cooling water supplied to the refrigerator,
A water storage tank provided in a lower part of the cooling tower for storing the cooling water;
A drain pipe for draining the cooling water from the water tank;
A water supply pipe for supplying makeup water for the cooling water from the upper side of the water tank,
The drain pipe is constituted by a rising portion and a falling portion, and an end portion of the rising portion is provided with a drain outlet disposed at a lower portion of the water storage tank, and the water storage tank is provided at an end portion of the falling portion. There is a discharge port arranged outside the
The rising portion and the lowering portion are connected at a position higher than the drain outlet and at a position lower than the side wall height of the water storage tank, and an upper end of the lowering portion is provided with an opening,
When replenishment water is replenished into the water tank from the water supply pipe, the water level in the rising part rises at the same time as the water level of the water tank rises, and the water in the rising part exceeds the height of the connecting part, the connection A cooling water supply / drainage method for a cooling tower, wherein the cooling water flows through the part to the descending part and drains from the drainage port of the descending part. The cooling water supply / drainage method of a cooling tower according to claim 1, wherein the drainage port is formed on a bottom surface or a lower side surface of the water storage tank. It is applied to a cooling tower group in which a plurality of the cooling towers according to claim 1 or 2 are arranged,
A cooling water sprinkling pipe provided at an upper part of the cooling tower and serving as the water supply pipe;
Outward piping and return piping for cooling water disposed between the cooling tower and the refrigerator,
A return common header for communicating the return pipes of the plurality of cooling towers;
A control device for measuring the conductivity of the cooling water in the return common header;
A makeup water supply pipe communicating with the return common header;
A cooling water supply / drainage for a cooling tower group, wherein the makeup water supply pipe is provided with an electric valve, and an amount of water supplied to the return common head is adjusted by the electric valve based on a measurement result of conductivity of the control device. Way . The water storage tanks of the plurality of cooling towers are provided with communication pipes that allow the water storage tanks to communicate with each other.
A water level meter for measuring the water level in the water tank is disposed in the communication pipe,
The said control apparatus adjusts the opening degree of the said electric valve | bulb based on the measurement result of the said water level meter, The cooling water supply / drainage method of the cooling tower group of Claim 3 characterized by the above-mentioned.

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