JP2005049073A - Fluid cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid cooling device for cooling a fluid, which has high antifreezing performance of a heat exchanger. <P>SOLUTION: This fluid cooling device comprises a condenser 16, a capillary tube 18, and the heat exchanger 25, which are provided on a refrigerant circuit 12 in which chlorofluorocarbon is circulated. In the refrigerant circuit 12, one end of a bypass circuit 29 is connected to the upstream side of the condenser 16, and the other end of the bypass circuit 29 is connected to the downstream side of the condenser 16. When the heat exchange load is small, or the outside air temperature is low, the bypass circuit 29 is opened by a solenoid valve 30, whereby chlorofluorocarbon is supplied to the capillary tube 18 so as to avoid the condenser 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fluid cooling device for cooling a fluid.

  Compressed air that drives a fluid pressure device such as an air cylinder is created using a compressor. Since the compressor sucks moisture in the atmosphere simultaneously with the atmosphere, the compressed air contains a large amount of water vapor. Since the amount of water vapor in the compressed air varies depending on the temperature, drain (water droplets) is generated if the temperature drop in the usage environment is severe. If this drain is supplied to the fluid pressure device, it may cause a failure. Therefore, the dry compressed air is supplied by removing water vapor contained in the compressed air.

  For example, refrigeration dryers are known for obtaining dry compressed air. The refrigeration dryer includes a fluid cooling device. When the compressed air from the compressor is cooled by the fluid cooling device, water vapor contained therein is condensed and removed as drainage. By removing water vapor contained in the compressed air, dry compressed air is obtained.

  As shown in FIG. 3, this type of fluid cooling device (see Patent Document 1) 51 includes a refrigerant circuit 52 in which chlorofluorocarbon as a refrigerant is circulated, and a heat exchanger provided on the refrigerant circuit 52. The compressed air flowing through the circuit to be cooled 54 is cooled by 53. By the way, although the cooling capacity of the heat exchanger 53 is constant, if the heat exchange load decreases or the outside air temperature decreases due to a decrease in the flow rate of the compressed air passing through the heat exchanger 53, the heat exchanger 53 Since the cooling capacity of 53 becomes relatively high, the inside of the heat exchanger 53 may be frozen.

Therefore, in the conventional fluid cooling device 51, the rotational speed of the blower fan 55a in the condenser 55 for condensing the flon compressed by the compressor 56 is controlled based on the temperature of the flon that has passed through the heat exchanger 53. is doing. That is, if the temperature of the chlorofluorocarbon gas exiting the heat exchanger 53 is high, the blower fan 55a is rotated at a high speed, whereas if the temperature of the chlorofluorocarbon gas is low, the blower fan 55a is rotated at a low speed. Thereby, the cooling temperature of the chlorofluorocarbon is adjusted according to the heat exchange load, so that the water removed from the compressed air is not frozen in the heat exchanger 53.
JP 2002-130847 A

  However, in the fluid cooling device 51 shown in Patent Document 1, when the heat exchange load or the outside air temperature rapidly decreases, the cooling capacity of the heat exchanger 53 can be increased by simply reducing the rotational speed of the blower fan 55a of the condenser 55. There is a risk that it cannot be reduced sufficiently. As a result, the heat exchanger 53 may be frozen. In addition, if the cooling capacity of the heat exchanger 53 cannot be sufficiently reduced, the chlorofluorocarbon cannot take heat in the heat exchanger 53, and most of the chlorofluorocarbon is discharged from the heat exchanger 53 in a liquid state. If liquid CFCs flow into the compressor 56, the compressor 56 may be damaged due to liquid compression.

  The present invention has been made paying attention to such problems existing in the prior art. The object is to provide a fluid cooling device with high antifreezing performance of the heat exchanger.

  According to the first aspect of the present invention, the refrigerant compression means for compressing the refrigerant, which is provided on the refrigerant circuit in which the refrigerant is circulated, and the fan that rotates the refrigerant compressed by the refrigerant compression means by driving the fan motor. Refrigerant condensing means for cooling with a fan and condensing, refrigerant expanding means for expanding the refrigerant condensed by the refrigerant condensing means, fluid to be cooled flowing in a circuit to be cooled that is a different path from the refrigerant circuit, and the refrigerant expanding means A heat exchanger for exchanging heat with the refrigerant expanded by the pressure, a pressure detection means for detecting the pressure of the refrigerant flowing downstream from the heat exchanger on the refrigerant circuit, and the pressure detection means. And a motor control unit that controls driving of a fan motor provided in the refrigerant expansion unit based on the pressure of the refrigerant. The spent refrigerant, and a bypass circuit for introducing the refrigerant expansion means to avoid the refrigerant condensing means, provided on the bypass circuit, and the gist that a bypass valve for opening and closing the same bypass circuit.

  With this configuration, when the heat exchange load in the heat exchanger is small, the motor control means controls the fan motor so that the rotational speed of the fan motor becomes small, and the cooling capacity of the heat exchanger is reduced. In addition to this, when the heat exchange load is small, the bypass valve is opened, and the refrigerant is supplied to the refrigerant condensing means so as to avoid the refrigerant condensing means. Therefore, since the cooling capacity of the heat exchanger can be greatly reduced, freezing can be prevented from occurring in the heat exchanger even when the heat exchange load and the outside air temperature are drastically lowered.

The gist of the invention described in claim 2 is that it comprises valve control means for electrically controlling opening and closing of the bypass valve based on the refrigerant pressure detected by the pressure detection means.
With this configuration, the opening and closing of the bypass valve is electrically controlled by the valve control means based on the pressure of the refrigerant flowing downstream from the heat exchanger. Therefore, since the cooling capacity of the heat exchanger is increased or decreased based on the refrigerant pressure that varies in proportion to the heat exchange load, the dew point temperature in the heat exchanger can be controlled with high accuracy.

  According to a third aspect of the present invention, the valve control means sets the bypass valve on condition that the refrigerant pressure detected by the pressure detection means is lower than a predetermined value and the driving of the fan motor is stopped. The gist is to open.

  According to this configuration, the drive control of the fan motor and the opening / closing control of the bypass valve are performed separately, so that the load on the motor control means and the valve control means can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the freeze prevention performance in a heat exchanger can be improved.

Hereinafter, an embodiment in which the present invention is embodied in a fluid cooling device for a refrigeration air dryer will be described with reference to the drawings.
As shown in FIG. 1, the refrigeration air dryer 10 includes a fluid cooling device 11 having a refrigerant circuit 12 that is a closed loop, and chlorofluorocarbon as a refrigerant is enclosed in the refrigerant circuit 12 so as to be circulated. On the refrigerant circuit 12, a compressor 15 is provided as refrigerant compression means for compressing gaseous chlorofluorocarbon. A condenser 16 as a refrigerant condensing means for condensing gaseous chlorofluorocarbon is provided downstream of the compressor 15 in the refrigerant circuit 12. The condenser 16 includes a cooling pipe 16a and a blower fan 16b. By rotating the blower fan 16b with a fan motor 16c, the high-temperature and high-pressure flon flowing through the cooling pipe 16a is cooled. On the refrigerant circuit 12, downstream of the condenser 16, a capillary tube 18 is provided as refrigerant expansion means for vaporizing liquid chlorofluorocarbon.

  The refrigeration air dryer 10 is provided with a circuit to be cooled 21 that is a different path from the refrigerant circuit 12. A pressure supply source 22 such as a compressor is connected to the upstream end of the circuit 21 to be cooled, and a fluid pressure device 23 such as an air cylinder is connected to the downstream end of the circuit to be cooled. The compressed air is supplied to the fluid pressure device 23 via the cooled circuit 21.

  A heat exchanger 25 is provided in part of the refrigerant circuit 12 and the cooled circuit 21. The heat exchanger 25 is of a plate type in which a plurality of corrugated plates are arranged at regular intervals, and chlorofluorocarbon and compressed air are alternately circulated in the gaps between the corrugated plates. Then, the heat exchanger 25 exchanges heat between the flon expanded and vaporized by the capillary tube 18 and the compressed air before being supplied from the pressure supply source 22 to the fluid pressure device 23. Here, the compressed air is cooled by the chlorofluorocarbon.

  On the downstream side of the heat exchanger 25 in the refrigerant circuit 12, a gas-liquid separator 26 that separates gaseous chlorofluorocarbon and liquid chlorofluorocarbon is provided, and only the gaseous chlorofluorocarbon is supplied to the compressor 15. On the other hand, on the downstream side of the heat exchanger 25 in the cooled circuit 21, the compressed air is cooled when it passes through the heat exchanger 25, so that the water vapor contained in the compressed air is condensed. A drain recovery device 27 is provided for recovering water.

Next, the main part of this embodiment will be described.
In the refrigerant circuit 12 in the fluid cooling device 11, a bypass circuit 29 in parallel with the condenser 16 is formed so as to avoid the condenser 16. The upstream end of the bypass circuit 29 is connected to a location located between the condenser 16 and the compressor 15 on the refrigerant circuit 12, and the downstream end of the bypass circuit 29 is connected to the condenser 16 and the capillary on the refrigerant circuit 12. The part located between the tubes 18 is connected. An electromagnetic valve 30 as a bypass valve is provided on the bypass circuit 29. When the electromagnetic valve 30 is opened, chlorofluorocarbon flows to the capillary tube 18 through both the refrigerant circuit 12 and the bypass circuit 29. When the electromagnetic valve 30 is closed, chlorofluorocarbon flows into the capillary tube 18 only through the refrigerant circuit 12.

  In the refrigerant circuit 12, a pressure sensor 31 serving as a pressure detection unit for detecting the pressure of the chlorofluorocarbon fluctuating in proportion to the heat exchange load is provided at a location located downstream of the heat exchanger 25. The pressure sensor 31 is electrically connected to a control computer 32. The control computer 32 controls driving of the fan motor 16 c that rotates the blower fan 16 b of the condenser 16 based on the pressure of the flon detected by the pressure sensor 31. That is, the control computer 32 controls the rotational speed of the fan motor 16c according to the pressure fluctuation of the chlorofluorocarbon flowing downstream of the heat exchanger 25, and when the chlorofluorocarbon pressure becomes low, the rotational speed of the blower fan 16b. When the pressure of the Freon is increased, the rotational speed of the fan motor 16c is increased. Then, the control computer 32 stops driving the fan motor 16c when the pressure of the chlorofluorocarbon becomes a predetermined value or less. Therefore, the control computer 32 constitutes motor control means.

  The control computer 32 controls the opening and closing of the electromagnetic valve 30 based on the CFC pressure detected by the pressure sensor 31. That is, the control computer 32 controls the solenoid valve 30 to open when the pressure of the chlorofluorocarbon is lower than a predetermined value even though the rotational speed of the blower fan 16b is minimized. When the chlorofluorocarbon pressure is higher than a predetermined value, the control computer 32 controls the solenoid valve 30 to close. Therefore, the control computer 32 constitutes a valve control means.

Next, the operation of the refrigeration air dryer 10 configured as described above will be described.
The chlorofluorocarbon gas compressed by the compressor 15 is cooled and liquefied by the blower fan 16b of the condenser 16. The liquefied Freon is rapidly cooled by being expanded and vaporized by the capillary tube 18 and supplied to the heat exchanger 25. The heat exchanger 25 exchanges heat between the cooled chlorofluorocarbon gas and the compressed air before being supplied from the pressure supply source 22 to the fluid pressure device 23. As a result, the compressed air is deprived of heat by the chlorofluorocarbon and cooled, and the drain generated by condensing the water vapor (moisture) contained therein is recovered by the drain recovery device 27. Furthermore, the compressed air dried by removing water vapor is raised to a predetermined temperature by a reheater (not shown) and supplied to the fluid pressure device 23.

  When the heat exchange load in the heat exchanger 25 fluctuates, the pressure of the Freon detected by the pressure sensor 31 also fluctuates with the fluctuation. In other words, when the amount of compressed air supplied to the fluid pressure device 23 decreases or the outside air temperature decreases, the heat exchange load in the heat exchanger 25 decreases, and the CFC detected by the pressure sensor 31 decreases. The pressure value also decreases. Then, the control computer 32 reduces the rotational speed of the fan motor 16c in accordance with the decrease in the pressure of the chlorofluorocarbon, and reduces the refrigerant condensing ability by the condenser 16. If the pressure value of the chlorofluorocarbon detected by the pressure sensor 31 falls below a predetermined value, the control computer 32 stops driving the fan motor 16c and prevents the blower fan 16b from rotating.

  When the fan motor 16c is stopped and the pressure value of the Freon detected by the pressure sensor 31 is further lowered, the control computer 32 opens the electromagnetic valve 30, and the high-temperature and high-pressure Freon gas sent from the compressor 15 is opened. Is bypassed upstream of the capillary tube 18 without passing through the condenser 16. After the predetermined time elapses, when the pressure value of the chlorofluorocarbon stops decreasing and rises to the predetermined pressure value again, the control computer 32 closes the electromagnetic valve 30 so that the chlorofluorocarbon does not flow through the bypass circuit 29.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) When the heat exchange load in the heat exchanger 25 is small, even when the rotation of the blower fan 16b of the condenser 16 is stopped, the pressure of the flon on the downstream side of the heat exchanger 25 is reduced. The cooling capacity of the heat exchanger 25 can be reduced by opening the bypass circuit 29 and reducing the amount of chlorofluorocarbon inflow into the condenser 16. Therefore, it is possible to prevent the drain generated in the heat exchanger 25 from freezing. In addition, since the cooling capacity of the heat exchanger 25 can be reduced, the chlorofluorocarbon does not take heat in the heat exchanger 25 and is not easily discharged from the heat exchanger 25 as liquid chlorofluorocarbon. Therefore, although the gas-liquid separator 26 is provided, liquid chlorofluorocarbon does not return to the compressor 15 beyond the gas-liquid separation capability. Therefore, since the compressor 15 that should originally compress gaseous chlorofluorocarbon does not compress liquid chlorofluorocarbon, it is possible to prevent the compressor 15 from being damaged.

  (2) The downstream end of the bypass circuit 29 is connected between the condenser 16 and the capillary tube 18 on the refrigerant circuit 12. Thereby, since the high temperature and Freon pumped from the compressor 15 are not supplied in the vicinity of the heat exchanger 25, it is possible to prevent the cooling capacity of the heat exchanger 25 from being extremely lowered, and the heat exchanger 25 It becomes easier to adjust the cooling capacity. Therefore, the compressed air can be cooled with stable dew point performance.

  (3) The opening and closing of the solenoid valve 30 is controlled based on the pressure of the chlorofluorocarbon flowing downstream from the heat exchanger 25. Therefore, since the cooling capacity of the heat exchanger 25 can be increased or decreased based on the pressure of Freon proportional to the heat exchange load, the dew point temperature in the heat exchanger 25 is controlled with fine and high accuracy. Can do.

  (4) For example, in the cooled circuit 21, temperature sensors are provided on the upstream side and the downstream side of the heat exchanger 25, respectively, and the cooling capacity of the heat exchanger 25 is set based on the temperature difference detected by the two temperature sensors. Compared with the adjustment, the number of pressure sensors 31 can be reduced to one in this embodiment. Therefore, since the number of parts can be reduced, cost reduction and simplification of the refrigeration air dryer 10 can be achieved.

(Another embodiment)
The embodiment of the present invention may be modified as follows.
A temperature sensor as temperature detecting means for detecting the temperature of the chlorofluorocarbon may be provided in place of the pressure sensor 31 at a location located downstream of the heat exchanger 25 in the refrigerant circuit 12. In the case of this configuration, the control computer 32 as the motor control means controls the driving of the fan motor 16c that rotates the blower fan 16b of the condenser 16 based on the temperature of the flon detected by the temperature sensor. That is, when the temperature of the chlorofluorocarbon is lowered, the rotational speed of the blower fan 16b is decreased, and when the temperature of the chlorofluorocarbon is increased, the rotational speed of the fan motor 16c is increased.

  The opening / closing of the solenoid valve 30 may be controlled based on the temperature of the Freon detected by the temperature sensor. In this case, the control computer 32 controls to open the electromagnetic valve 30 when the temperature of the flon is lower than the predetermined value even though the rotational speed of the blower fan 16b is equal to or lower than the predetermined value. When the chlorofluorocarbon temperature is higher than a predetermined value, the control computer 32 controls the solenoid valve 30 to close.

  In the above embodiment, when the pressure of the chlorofluorocarbon becomes a predetermined value or less, the drive of the fan motor 16c is stopped by the control computer 32, but it may be rotated at an extremely low rotational speed instead of being stopped.

  In the above-described embodiment, the solenoid valve 30 is set on condition that the rotation speed of the fan motor 16c of the blower fan 16b is minimum, that is, the chlorofluorocarbon pressure does not decrease after a lapse of a certain time after the blower fan 16b stops. Controlled to open. In addition to this control method, the solenoid motor 30 may be opened simultaneously with stopping the fan motor 16c. Alternatively, the electromagnetic valve 30 may be controlled to be opened on the condition that the pressure of the chlorofluorocarbon does not decrease after a predetermined time has elapsed after the rotational speed of the fan motor 16c becomes lower than a predetermined value.

  In the above embodiment, the electromagnetic valve 30 is opened and closed by turning it on and off. However, the electromagnetic valve is capable of adjusting the flow rate of Freon flowing through the bypass circuit 29 by an electrical signal from the control computer 32. It may be changed.

In the above embodiment, the electromagnetic valve 30 is configured to be electrically opened and closed, but may be changed to a bypass valve that is manually opened and closed instead of the electromagnetic valve 30.
-In the said embodiment, although it actualized to the fluid cooling device 11 of the refrigeration type dryer, it changes into arbitrary uses, such as a fluid cooling device for cooling the coolant used when processing a workpiece | work with a machine tool, for example. Is possible.

-Instead of Freon, the refrigerant may be changed to air, water, brine (antifreeze) or ammonia.
-By using the capacity control of the refrigeration compressor (for example, an inverter), it is possible to obtain a fine and precise cooling capacity.

  In the above embodiment, the fluid cooling device 11 using the air-cooled condenser 16 that rotates the blower fan 16b by the fan motor 16c is embodied. However, the fluid cooling device 11 using the water-cooled condenser 16 is changed. May be. That is, as shown in FIG. 2, the condenser 16 is provided with a cold water passage 41 through which cooling water flows, and heat is exchanged between the cooling water flowing through the cold water passage 41 and chlorofluorocarbons flowing through the refrigerant circuit 12. The high-temperature, high-pressure chlorofluorocarbon flowing through 16a is cooled. In this case, the cooling water passage 41 is provided with a cooling water amount adjusting valve (control valve) 42 that is used instead of the fan motor 16c. And the control computer 32 controls the opening degree of the cooling water amount adjusting valve 42 according to the pressure fluctuation of the chlorofluorocarbon flowing on the downstream side of the heat exchanger 25. When the pressure of the chlorofluorocarbon becomes low, the cooling water amount adjusting valve is controlled. If the opening degree of 42 is reduced and the pressure of Freon is increased, the opening degree of the cooling water amount adjusting valve 42 is increased. Further, the control computer 32 completely closes the cooling water amount adjusting valve 42 when the pressure of the chlorofluorocarbon becomes a predetermined value or less.

Next, in addition to the technical idea described in the claims, the technical idea grasped by the above-described embodiment will be described below.
[1] A refrigerant compression unit that is provided on a refrigerant circuit in which the refrigerant is circulated and compresses the refrigerant, and the refrigerant compressed by the refrigerant compression unit is cooled by a blower fan that rotates using a fan motor as a drive source. Refrigerant condensing means for condensing, refrigerant expanding means for expanding the refrigerant condensed by the refrigerant condensing means, fluid to be cooled flowing in a circuit to be cooled which is a different path from the refrigerant circuit, and refrigerant expanded by the refrigerant expanding means A heat exchanger that exchanges heat with the heat exchanger, a temperature detector that detects a temperature of the refrigerant that flows on the downstream side of the heat exchanger on the refrigerant circuit, and a temperature of the refrigerant that is detected by the temperature detector And a motor control unit that controls driving of a fan motor provided in the expansion unit, and the refrigerant that has passed through the refrigerant compression unit is used as the refrigerant. A fluid cooling apparatus comprising: a bypass circuit that is introduced into the refrigerant expansion means so as to avoid the condensing means; and a bypass valve that is provided on the bypass circuit and opens and closes the bypass circuit. According to this configuration, it is possible to prevent freezing from occurring in the heat exchanger even when the heat exchange load or the outside air temperature rapidly decreases.

  [2] A fluid cooling device including valve control means for electrically controlling opening and closing of the bypass valve based on the refrigerant temperature detected by the temperature detection means in [1]. With this configuration, the dew point temperature in the heat exchanger can be controlled with high accuracy.

  [3] In the above [2], the valve control means opens the bypass on the condition that the refrigerant pressure detected by the pressure detection means is lower than a predetermined value and the driving of the fan motor is stopped. Fluid cooling device. With this configuration, the load on the motor control means and the valve control means can be reduced.

  [4] Refrigerant compression means for compressing the refrigerant provided on the refrigerant circuit through which the refrigerant is circulated, and refrigerant compressed on the refrigerant circuit downstream of the refrigerant compression means and compressed by the refrigerant compression means And a refrigerant condensing unit that cools and condenses by a blower fan that rotates using a fan motor as a driving source, and is provided downstream of the refrigerant condensing unit on the refrigerant circuit, and expands the refrigerant condensed by the refrigerant condensing unit A refrigerant expansion means; and a refrigerant that is provided on the downstream side of the refrigerant expansion means on the refrigerant circuit and that flows to a cooled circuit that is a different path from the refrigerant circuit, and a refrigerant expanded by the refrigerant expansion means. A heat exchanger for exchanging heat, pressure detection means for detecting the pressure of refrigerant flowing downstream from the heat exchanger on the refrigerant circuit, and detection by the pressure detection means And a motor control means for controlling the drive of a fan motor provided in the expansion means based on the pressure of the refrigerant to be avoided. The refrigerant that has passed through the refrigerant compression means is avoided from the refrigerant condensation means. And providing a bypass circuit to be introduced into the refrigerant expansion means, and connecting the upstream end of the bypass circuit to a location located between the refrigerant compression means and the refrigerant condensation means in the refrigerant circuit, and the downstream end of the bypass circuit. Is connected to a location located between the refrigerant condensing means and the refrigerant expanding means in the refrigerant circuit, and a fluid cooling device is provided on the bypass circuit with a bypass valve for opening and closing the bypass circuit. With this configuration, it is possible to prevent freezing in the heat exchanger when the heat exchange load in the heat exchanger is small.

An explanatory view of a refrigerating type air dryer provided with a fluid cooling device in one embodiment. Explanatory drawing which shows a part of refrigeration type air dryer in another embodiment. Explanatory drawing of the fluid cooling device in background art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Fluid cooling device, 12 ... Refrigerant circuit, 15 ... Compressor (refrigerant compression means), 16 ... Condenser (refrigerant condensation means), 16b ... Blower fan, 16c ... Fan motor, 18 ... Capillary tube (refrigerant expansion means) 21 ... Circuit to be cooled, 25 ... Heat exchanger, 29 ... Bypass circuit, 30 ... Solenoid valve (bypass valve), 31 ... Pressure sensor (pressure detection means), 32 ... Control computer (motor control means, valve control means) .

Claims (3)

Refrigerant compression means for compressing the refrigerant circulated in the refrigerant circuit;
Refrigerant condensing means for cooling and condensing the refrigerant compressed by the refrigerant compressing means with a blower fan that rotates by driving a fan motor;
Refrigerant expansion means for expanding the refrigerant condensed by the refrigerant condensation means;
A heat exchanger for exchanging heat between a fluid to be cooled flowing in a circuit to be cooled that is separate from the refrigerant circuit and the refrigerant expanded by the refrigerant expansion means;
Pressure detecting means for detecting the pressure of the refrigerant flowing on the downstream side of the heat exchanger on the refrigerant circuit;
A fluid cooling device comprising: motor control means for controlling drive of a fan motor provided in the refrigerant expansion means based on the refrigerant pressure detected by the pressure detection means;
A bypass circuit for introducing the refrigerant that has passed through the refrigerant compression means into the refrigerant expansion means so as to avoid the refrigerant condensation means;
A fluid cooling apparatus, comprising: a bypass valve provided on the bypass circuit and opening and closing the bypass circuit. 2. The fluid cooling device according to claim 1, further comprising valve control means for electrically controlling opening and closing of the bypass valve based on a refrigerant pressure detected by the pressure detection means. The valve control means opens the bypass on condition that the pressure of the refrigerant detected by the pressure detection means is lower than a predetermined value and the drive of the fan motor is stopped. The fluid cooling device as described.

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