JP2017180889A - Refrigerant circulation device and refrigerant circulation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerant circulation device capable of decompressing pressure in a reservoir tank safely and efficiently, and a refrigerant circulation method.SOLUTION: A refrigerant circulation device includes: a reservoir tank configured to store refrigerant with a gas-phase part and a liquid-phase part; a circulation line including a pump, a refrigeration part and a cooling object, and configured to feed cooled refrigerant back to the liquid-phase part; and a decompression line branched from any position between pump and the cooling object of the circulation line to split part of refrigerant, and disposed so as to passing through the gas-phase part and then feeding refrigerant back to the liquid-phase.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigerant circulation device and a refrigerant circulation method.

  In cooling a high-temperature superconducting power device using a high-temperature superconducting wire, a low-temperature liquefied gas (generally liquid nitrogen) in a subcool (supercooled) state is often used as a refrigerant. Specifically, the superconducting power equipment is cooled when circulating the liquid nitrogen while maintaining the subcooled state.

  Here, as a refrigerator for cooling and maintaining liquid nitrogen in a subcooled state, a Brayton refrigerator, a Stirling refrigerator, or the like is generally known. In addition, when cooling a high-temperature superconducting power device, since the circulation pressure and temperature of liquid nitrogen differ depending on the device to be cooled, it is necessary to appropriately control them.

By the way, Patent Document 1 discloses a cooling method for a superconducting device. Also, in FIG.
The structure of the conventional refrigerant | coolant circulation apparatus disclosed by patent document 1 is shown. As shown in FIG. 3, a conventional refrigerant circulation device 101 includes a reservoir tank (storage container) 102 in which refrigerant is stored, a pressure measuring device 103 that measures the pressure in the gas phase portion 102A of the reservoir tank 102, and a refrigerant. A circulation line L101 that circulates in a liquid state, a pump 104 and a refrigerator 105 provided in the circulation line L101, a high-temperature superconducting power device 106 to be cooled, and one end are provided in a gas phase portion 102A in the reservoir tank 102, The other end is schematically configured to include a bypass line L102 joined to a circulation line L101 at a position between the high temperature superconducting power device 106 and the reservoir tank 102, and a valve 107 provided in the bypass line L102.

  The reservoir tank 102, the circulation line L101, and the bypass line L102 are in a sealed state. Further, regarding the temperature and pressure in the reservoir tank 102, there is a temperature difference (up to several K) from the upper part to the lower part of the liquid phase part 102B due to the nature of the subcool state, and the bottom is cooler due to the difference in density. ing. Further, the gas phase portion 102A has a temperature distribution such that the temperature is room temperature on the upper side of the container, and the surface temperature of the liquid is on the liquid surface side. The pressure in the gas phase portion 102A is a saturated vapor pressure determined by the surface temperature of the liquid. Thus, it is preferable that temperature distribution exists in the gas phase portion 102A and the liquid phase portion 102B.

  Further, in the conventional refrigerant circulation device 101, the pump 104 is installed outside the reservoir tank 102. Then, the liquid refrigerant sent out from the pump 104 is cooled to the subcooled state by the refrigerator 105, and then the high-temperature superconducting power device 106 is cooled and returned again to the liquid phase part 102B of the reservoir tank 102. A circulation cycle is formed. In the circulation cycle, the refrigerant is continuously cooled by the refrigerator and is maintained in the subcooled state.

  By the way, when the temperature of the refrigerant rises due to an increase in the cooling load to be cooled, the volume of the gas phase portion 102A in the reservoir tank 102 decreases and the pressure in the reservoir tank 102 rises. In order to adjust the pressure in the reservoir tank 102, a pressure reducing mechanism is provided.

  Specifically, the initial pressure reducing mechanism is a mechanism that discharges a part of the gas phase portion of the refrigerant to the outside of the reservoir tank.

  On the other hand, in the conventional refrigerant circulation device 101 disclosed in Patent Document 1, between the gas phase portion 102A in the reservoir tank 102 and the circulation line L101 after cooling the high-temperature superconducting power device 106 to be cooled. A pressure reducing mechanism is configured by the provided bypass line L102 and the valve 107 provided in the bypass line L102. As a decompression method using this decompression mechanism, first, the valve 107 is opened, and the gaseous refrigerant is brought into contact with the liquid refrigerant in the circulation line L101. Thereby, since the gaseous refrigerant is condensed, it is liquefied. Then, the inside of the reservoir tank 102 is decompressed by returning the liquefied refrigerant to the liquid phase portion 102B in the reservoir tank 102.

JP 2014-126283 A

  However, in the conventional pressure reducing mechanism of the refrigerant circulation device, the cooling and condensation of the refrigerant in the gaseous state is performed only on the gas-liquid contact surface in the thin pipe serving as the circulation line, so that there is a problem that the efficiency of cooling and condensation is poor. there were. Further, when the cooling load to be cooled increases and the temperature of the refrigerant rises, there is a possibility that the decompression capacity is insufficient. Moreover, since the pressure is lower than that of the circulation line when the gas is taken out from the gas phase portion, there is a possibility that the gas cannot be taken out efficiently or the refrigerant may flow backward from the circulation line to the bypass line.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the refrigerant | coolant circulation device and refrigerant | coolant circulation method which can decompress | depressurize the inside of a reservoir tank safely and efficiently.

In order to solve this problem, the present invention has the following configuration.
That is, the invention according to claim 1 is a reservoir tank that stores a refrigerant in a state where a gas phase portion and a liquid phase portion are provided, a pump that pumps the refrigerant from the liquid phase portion, and cools the pumped refrigerant. A refrigeration unit and a cooling object to be cooled by the cooled refrigerant are provided, a circulation line for returning the cooled refrigerant to the liquid phase part, and between the pump and the cooling object in the circulation line And a decompression line that branches off from any of the positions and distributes a part of the refrigerant, and returns the refrigerant to the liquid phase part after being arranged to pass through the gas phase part. It is a circulation device.

  The invention according to claim 2 is the refrigerant circulation device according to claim 1, wherein a condenser is provided in the decompression line located in the gas phase portion.

  The invention according to claim 3 is the refrigerant circulation device according to claim 1 or 2, wherein a flow rate adjusting valve is provided in the decompression line.

  The invention according to claim 4 is the refrigerant circulation device according to any one of claims 1 to 3, comprising a pressure measuring device that measures the pressure of the gas phase portion.

  The invention according to claim 5 includes a control unit that is electrically connected to the pressure measuring device and the flow control valve, and that controls an opening of the flow control valve based on a pressure value of the pressure measuring device. The refrigerant circulation device according to claim 4.

  The invention according to claim 6 is the refrigerant circulation device according to any one of claims 1 to 5, wherein the refrigerant is liquid nitrogen.

  In the invention according to claim 7, the refrigerant is extracted and cooled from the reservoir tank storing the refrigerant in a state where the gas phase portion and the liquid phase portion are provided, and after cooling the object to be cooled, the refrigerant is returned to the liquid phase portion. A refrigerant circulation method, wherein when the pressure in the reservoir tank rises, at least a part of the refrigerant before cooling the cooling target is separated to cool the gas phase part in the reservoir tank. It is a refrigerant circulation method which returns to the said liquid phase part after a while.

  The refrigerant circulation device of the present invention includes a reservoir tank that stores refrigerant in a state where a gas phase portion and a liquid phase portion are provided, a pump that pumps the refrigerant from the liquid phase portion, a refrigeration unit that cools the pumped refrigerant, and In a refrigerant circulation device provided with a cooling object to be cooled by the cooled refrigerant and having a circulation line for returning the cooled refrigerant to the liquid phase part, any of the circulation line between the pump and the object to be cooled is provided. Branching off from that position and diverting a part of the refrigerant, and is provided with a pressure reducing line for returning the refrigerant to the liquid phase part after being arranged to pass through the gas phase part. Since the refrigerant in the gas phase can be cooled and condensed by heat exchange between the low temperature refrigerant (the refrigerant before cooling the object to be cooled) and the gas phase, the pressure in the reservoir tank can be reduced safely and efficiently. . Furthermore, by providing a condenser in the decompression line located in the gas phase portion, it is possible to provide sufficient decompression capability.

  In the refrigerant circulation method of the present invention, the refrigerant is extracted and cooled from a reservoir tank that stores the refrigerant in a state where the gas phase part and the liquid phase part are provided, and the refrigerant to be cooled is returned to the liquid phase part after being cooled. In the circulation method, when the pressure in the reservoir tank rises, at least a part of the refrigerant before cooling the object to be cooled is collected and cooled to the liquid phase part after the gas phase part in the reservoir tank is cooled. Therefore, the inside of the reservoir tank can be decompressed safely and efficiently.

It is a distribution diagram showing the composition of the refrigerant circulation device which is one embodiment to which the present invention is applied. It is a systematic diagram which shows the structure of the refrigerant | coolant circulation apparatus which is other embodiment to which this invention is applied. It is a systematic diagram which shows the structure of the conventional refrigerant | coolant circulation apparatus.

  Hereinafter, a refrigerant circulation device which is an embodiment to which the present invention is applied will be described in detail with reference to the drawings together with a refrigerant circulation method using the refrigerant circulation device. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

First, an example of a configuration of a refrigerant circulation device that is an embodiment to which the present invention is applied will be described.
FIG. 1 is a system diagram showing a configuration of a refrigerant circulation device which is an embodiment to which the present invention is applied. In addition, the arrow shown in FIG. 1 has shown the moving direction of the refrigerant | coolant.
As shown in FIG. 1, the refrigerant circulation device 1 of the present embodiment includes a reservoir tank 2, a pressure measuring device 3 provided in the reservoir tank 2, a circulation line L1 through which liquid refrigerant circulates, and a circulation line L1. The pump 4, the refrigerator 5, the high-temperature superconducting power device 6 to be cooled, and a position P between the pump 4 and the refrigerator 5 in the circulation line L 1, and the gas phase in the reservoir tank 2. The pressure reduction line L2 which returns a refrigerant | coolant to the liquid phase part 2B after arrange | positioning so that it may pass through the part 2A, and the valve | bulb 7 and the condenser 8 which were provided in the pressure reduction line L2 are comprised roughly. Moreover, this embodiment demonstrates the case where liquid nitrogen is used as a refrigerant | coolant.

  The reservoir tank 2 is a container having a sealed structure, and stores the refrigerant in a state in which a gas phase part and a liquid phase part are provided inside the container. Specifically, as the reservoir tank 2, for example, a sealed container made of SUS304 having an internal volume of 1000 L can be used. The configuration of the reservoir tank 2 is not limited to this as long as it has low temperature resistance and pressure resistance, and an arbitrary size and material can be appropriately selected.

  The pressure measuring device 3 has a function of measuring the pressure of the gas phase portion 2A in the reservoir tank 2 and displaying the value. Examples of the pressure measuring device 3 applicable to the present embodiment include a Bourdon tube type pressure gauge. In addition, the structure of the pressure measuring device 3 is not limited to this, The pressure measuring device which has arbitrary functions can be selected suitably. Moreover, you may have an external output as a display of a measured value.

  The circulation line L1 takes out the refrigerant in the liquid state from the liquid phase part 2B of the reservoir tank 2, supplies it to the object to be cooled provided on the outside of the reservoir tank 2 and cools it, and again supplies the cooled refrigerant to the reservoir tank. It is a refrigerant | coolant supply path | route for returning to the 2 liquid phase part 2B. Specifically, one end of the circulation line L1 is provided so as to be in the liquid phase portion 2B of the reservoir tank 2, and once passes through the outside of the reservoir tank 2, the other end is in the liquid phase portion 2B of the reservoir tank 2. It is provided to become. As a result, the liquid refrigerant in the liquid phase portion 2B can be circulated outside the reservoir tank 2.

  The circulation line L1 includes a pump 4 that pumps the refrigerant from the liquid phase part 2B, a refrigeration unit 5 that cools the pumped refrigerant, and a high-temperature superconducting power device (cooling target) 6 that is cooled by the cooled refrigerant. Is provided. Examples of the circulation line L1 applicable to the present embodiment include a flexible vacuum heat insulating pipe made of SUS304 having an outer diameter of about 125 mm and a thickness of 1 mm. In addition, the structure of the circulation line L1 is not limited to this, Arbitrary sizes and materials can be selected suitably.

The pump 4 is provided in the circulation line L1. Examples of the pump 4 applicable to the present embodiment include a total lift of about 24 m, a discharge amount of 3 m ³ / h, and a self-priming centrifugal pump for liquid nitrogen. In addition, the structure of the pump 4 is not limited to this, The capability and the style pump corresponding to the refrigerant | coolant to be used can be selected suitably.

  In the present embodiment, the pump 4 is provided in the liquid phase portion 2B inside the reservoir tank 2, but the installation position is not limited to this. For example, it may be provided in another container filled with a liquid state refrigerant, or may be provided outside the gas phase portion 2 </ b> A or the reservoir tank 2.

  The refrigerator 5 is provided in the circulation line L <b> 1 in order to continuously cool the liquid state refrigerant to a subcooled state. Examples of the refrigerator 5 applicable to the present embodiment include a turbine-type refrigerator having a refrigeration capacity of 2 kW. In addition, the structure of the refrigerator 5 is not limited to this, The refrigerator of arbitrary capacity | capacitances and styles can be selected suitably.

  The high-temperature superconducting power device 6 is provided in the circulation line L1 as a cooling target of the refrigerant circulation device 1 of the present embodiment. However, the cooling target cooled by the refrigerant is not limited to this, and an arbitrary target can be cooled.

  In the refrigerant circulation device 1 of the present embodiment, the above-described reservoir tank 2, the circulation line L1, the pump 4, and the refrigerator 5 constitute a cooling mechanism for cooling the high-temperature superconducting power device 6 to be cooled.

  The decompression line L2 is a liquid refrigerant circulation path provided to decompress the pressure in the reservoir tank 2 when the pressure in the reservoir tank 2 increases. Specifically, one end of the decompression line L2 is provided at a position P between the pump 4 and the refrigerator 5 in the circulation line L1, and is disposed so as to pass through the gas phase part 2A from the outside of the reservoir tank 2. After that, the other end is provided in the liquid phase part 2B of the reservoir tank 2. Thus, a part of the liquid state refrigerant in the circulation line L1 is diverted from the position P into the decompression line L2, and the refrigerant in the decompression line L2 is cooled to cool the gaseous state refrigerant in the gas phase portion 2A. Can be used.

  Examples of the decompression line L2 applicable to the present embodiment include a pipe made of SUS304 having an outer diameter of about 21.7 mm and a thickness of 1 mm. In addition, the structure of the pressure reduction line L2 is not limited to this, Arbitrary sizes and materials can be selected suitably.

  The valve 7 is an on-off valve for supplying liquid refrigerant to the decompression line L2 in order to decompress the pressure when the pressure in the reservoir tank 2 becomes high. That is, the valve 7 is opened when the reservoir tank 2 is depressurized, and is closed when the reservoir tank 2 is not depressurized. Examples of the valve 7 applicable to the present embodiment include a ball valve. The configuration of the valve 7 is not limited to this, and any type of valve can be selected as appropriate.

  Further, the valve 7 may be configured to control the flow rate of the fluid. In this case, it is possible to cope with a sudden pressure increase in the reservoir tank 2 by installing a condenser 8 having a sufficient capacity in advance.

  The condenser 8 is a heat exchanger provided in the gas phase portion 2A in the reservoir tank 2 in order to reduce the pressure when the pressure in the reservoir tank 2 becomes high. The condenser 8 can cool and condense the gaseous refrigerant by exchanging heat between the refrigerant in the decompression line L2 and the gaseous refrigerant in the gas phase portion 2A. Thereby, the inside of the reservoir tank 2 is depressurized. Examples of the condenser 8 that can be applied to the present embodiment include a heat exchanger having a heat transfer capacity of 1000 W and a spiral tube type stainless steel heat exchanger. In addition, the structure of the condenser 8 is not limited to this, The heat exchanger of arbitrary ability and a mode can be selected suitably.

  In the refrigerant circulation device 1 of the present embodiment, the decompression line L2, the valve 7, and the condenser 8 described above constitute a decompression mechanism for decompressing the inside of the reservoir tank 2.

Next, an example of the configuration of the refrigerant circulation method of the present embodiment using the refrigerant circulation device 1 described above will be described.
In the refrigerant circulation method of the present embodiment, the refrigerant is extracted and cooled from the reservoir tank 2 that stores the refrigerant in a state where the gas phase part 2A and the liquid phase part 2B are provided. 2B is a refrigerant circulation method for returning to the tank 2B, and when the pressure in the reservoir tank 2 rises, at least a part of the refrigerant before cooling the object to be cooled is collected and the gas phase portion 2A in the reservoir tank 2 is collected. Is cooled and then returned to the 2B liquid phase part.

  Specifically, as shown in FIG. 1, first, the pump 4 is operated with a constant capacity, and a liquid refrigerant is continuously supplied to the circulation line L1. Next, the refrigerator 5 is operated with a constant capacity to bring the refrigerant into a subcooled state. Next, the subcooled refrigerant is supplied to the high-temperature superconducting power device 6 to be cooled for cooling. Thereafter, the refrigerant after cooling the object to be cooled is returned to the liquid phase part 2B in the reservoir tank 2 through the circulation line L1. By continuously performing the above cycle (that is, performing a cooling operation), the high-temperature superconducting power device 6 to be cooled can be cooled to a desired temperature.

Next, a method for reducing the pressure when the pressure in the reservoir tank 2 increases will be described.
First, when the cooling operation is performed by the refrigerant circulation device 1, the pressure of the gas phase part 2 </ b> A of the reservoir tank 2 is monitored using the pressure measuring device 3. When the pressure value of the pressure measuring device 3 exceeds a specified pressure value, the valve 7 provided in the decompression line L2 is opened. When the flow rate of the valve 7 can be adjusted, the amount of refrigerant flowing through the decompression line L2 is adjusted as appropriate.

  As a result, a part of the liquid refrigerant flowing through the circulation line L1 is divided into the decompression line L2, and the liquid refrigerant is supplied to the condenser 8 provided in the gas phase portion 2A inside the reservoir tank 2. The In this condenser 8, by exchanging heat between the refrigerant flowing in the decompression line L2 and the gas phase portion 2A in the reservoir tank 2, the heat of the gas phase portion 2A is transferred to the liquid state refrigerant, thereby allowing the gas phase The refrigerant in the gaseous state of the part 2A is cooled and condensed. Thereby, the inside of the reservoir tank 2 can be decompressed. Further, the condensed refrigerant is gently sent to the liquid phase portion 2B in the reservoir tank 2. Thereafter, when the pressure value of the pressure measuring device 3 reaches a specified pressure value, the valve 7 provided in the pressure reducing line L2 is closed.

  As described above, according to the refrigerant circulation device 1 of the present embodiment, the reservoir tank 2 that stores the refrigerant in the state where the gas phase portion 2A and the liquid phase portion 2B are provided, and the pressure value in the gas phase portion 2A. A pressure measuring device 3 for measuring the pressure, a pump 4 for pumping the refrigerant from the liquid phase part 2B, a freezing unit 5 for cooling the pumped refrigerant, and a high-temperature superconducting power device (cooling target) 6 cooled by the cooled refrigerant. A circulation line L1 is provided to return the cooled refrigerant to the liquid phase part 2B, and a part of the refrigerant is branched by branching from the position P between the pump 4 and the freezing part 5 of the circulation line L1. In addition, there is provided a valve 7 and a condenser 8 for exchanging heat in the gas phase part 2A, and a pressure reducing line L2 for returning the refrigerant to the liquid phase part. Low-temperature refrigerant (cool the object to be cooled The refrigerant in the gas phase portion 2A can be sufficiently cooled and condensed by heat exchange between the gas phase portion 2A and the gas phase portion 2A, so that the reservoir tank 2 can be decompressed safely and efficiently. .

  According to the refrigerant circulation method of the present embodiment, the refrigerant is extracted and cooled from the reservoir tank 2 that stores the refrigerant in a state where the gas phase portion 2A and the liquid phase portion 2B are provided, and after the cooling target is cooled, the refrigerant is In the cooling operation for returning to the phase part 2B, when the pressure in the reservoir tank 2 rises, a part of the low-temperature refrigerant before cooling the object to be cooled is collected, and the gas phase part 2A in the reservoir tank 2 is collected. Since the gaseous refrigerant in the gas phase part 2A is cooled by heat exchange with the liquid phase part 2B and then returned to the liquid phase part 2B, the inside of the reservoir tank 2 can be decompressed safely and efficiently.

  Further, according to the refrigerant circulation device 1 and the refrigerant circulation method of the present embodiment, the decompression line L2 is arranged in the gas phase portion 2A, and the liquid state refrigerant and gas flowing through the decompression line L2 by the condenser 8 provided there. Since the heat exchange with the gaseous refrigerant in the phase portion 2A is performed, the gaseous refrigerant can be efficiently cooled and condensed. Therefore, even if the cooling load to be cooled increases and the temperature of the refrigerant rises, there is no possibility that the decompression capacity is insufficient.

  In addition, according to the refrigerant circulation device 1 and the refrigerant circulation method of the present embodiment, the pressure reduction line L2 branched from the circulation line L1 is arranged in the gas phase part 2A, so that the gas phase having a lower pressure than the circulation line L1 is provided. There is no need to take out the refrigerant in the gaseous state (refrigerant gas) from the part 2A and bring it into gas-liquid contact with the refrigerant in the liquid state outside the reservoir tank 2, so that the refrigerant gas cannot be taken out efficiently or the refrigerant gas is taken out. There is no risk of the liquid refrigerant flowing back into the pipe. Therefore, the inside of the reservoir tank 2 can be decompressed safely.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. In the refrigerant circulation device 1 of the above-described embodiment, the configuration in which the operator manually controls opening and closing of the valve 7 has been described as an example, but the configuration is not limited thereto. Specifically, for example, a control unit electrically connected to the pressure measuring device 3 and the valve 7 may be provided, and the opening and closing of the valve 7 may be automatically controlled by the control unit. Furthermore, it is good also as a structure which adjusts the opening degree of a valve | bulb automatically and controls the flow volume of a refrigerant | coolant automatically.

  Moreover, in the refrigerant | coolant circulation apparatus 1 of embodiment mentioned above, although the structure where the pressure reduction line L2 branches from the position P between the pump 4 of the circulation line L1 and the refrigerator 5 was demonstrated, it is not limited to this. Instead, any position between the pump 6 and the high-temperature superconducting power device 6 to be cooled (that is, the refrigerant before cooling the object to be cooled) may be used. Specifically, for example, as shown in FIG. 2, the branch of the decompression line L2 may be branched from a position P ′ between the refrigerator 5 and the high-temperature superconducting power device 6 to be cooled. According to the refrigerant circulation device 21 having the configuration shown in FIG. 2, since the liquid refrigerant supplied to the condenser 8 can be set to a lower temperature, the gas phase portion 2 </ b> A can be cooled and condensed more efficiently.

  Moreover, in the refrigerant | coolant circulation apparatus 1 of embodiment mentioned above, although the other end of the pressure reduction line L2 demonstrated the structure used as the liquid phase part 2B, it is not limited to this, The refrigerant | coolant conveyed by the pressure reduction line L2 is not limited to this. The other end of the decompression line L2 may be in the gas phase portion 2A as long as it is a structure that is gently sent to the liquid phase portion 2B. In this case, a higher effect of cooling and condensation of the gas phase portion 2A can be expected by the liquid state refrigerant discharged to the gas phase portion 2A. In addition, since it will be in the state in which the temperature difference in the gaseous-phase part 2A will be lose | eliminated if discharge | release of the refrigerant | coolant of a liquid state to the gaseous-phase part 2A is intense, it is preferable to care so that a balance may not be disturbed largely.

  Moreover, in the refrigerant | coolant circulation apparatus 1 of embodiment mentioned above, although the structure which provides the condenser 8 in the pressure_reduction | reduced_pressure line L2 arrange | positioned in the gaseous-phase part 2A was demonstrated, it is not limited to this, A gaseous-phase part is provided. A configuration in which the condenser 8 is not provided may be used as long as the pressure reducing line L2 and the gas phase part 2A arranged to pass through can exchange heat. When heat exchange with the gas phase part 2A is performed in the decompression line L2 without providing the condenser 8, the distance of the decompression line L2 provided in the gas phase part 2A is increased, and a material having good thermal conductivity is used. It is preferable.

DESCRIPTION OF SYMBOLS 1 Refrigerant circulation apparatus 2 Reservoir tank 2A Gas phase part 2B Liquid phase part 3 Pressure measuring device 4 Pump 5 Refrigerator 6 High-temperature superconducting power equipment (cooling object 9
7 Valve 8 Condenser P, P 'Branch point (position)
L1 Circulation line L2 Pressure reduction line

Claims (7)

A reservoir tank for storing a refrigerant in a state where a gas phase portion and a liquid phase portion are provided;
A pump that pumps the refrigerant from the liquid phase part, a refrigeration part that cools the pumped refrigerant, and a cooling target that is cooled by the cooled refrigerant are provided, and the cooled refrigerant is returned to the liquid phase part Circulation line to
The liquid phase part after being arranged to branch from any position of the circulation line between the pump and the object to be cooled to divert part of the refrigerant and to pass through the gas phase part. And a decompression line for returning the refrigerant to the refrigerant circulation device.   The refrigerant circulation device according to claim 1, wherein a condenser is provided in the decompression line located in the gas phase part.   The refrigerant circulation device according to claim 1, wherein a flow rate adjustment valve is provided in the decompression line.   The refrigerant circulation device according to any one of claims 1 to 3, further comprising a pressure measurement device that measures a pressure of the gas phase portion.   The refrigerant circulation according to claim 4, further comprising a control unit that is electrically connected to the pressure measurement device and the flow rate control valve, and that controls an opening degree of the flow rate control valve based on a pressure value of the pressure measurement device. apparatus.   The refrigerant circulation device according to any one of claims 1 to 5, wherein the refrigerant is liquid nitrogen. A refrigerant circulation method for extracting and cooling a refrigerant from a reservoir tank that stores the refrigerant in a state where a gas phase part and a liquid phase part are provided, and returning the refrigerant to the liquid phase part after cooling the object to be cooled,
When the pressure in the reservoir tank rises, at least a part of the refrigerant before cooling the cooling target is collected, and the vapor phase portion in the reservoir tank is cooled, and then returned to the liquid phase portion. Refrigerant circulation method.

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