Circulating device for two-phase cooling systems and refrigerant circulation method in a two-phase cooling system circulating device

Abstract

A circulation device (100) for a two-phase cooling system comprises: an inlet-side connection portion (41) and an outlet-side connection portion (42); and a bypass flow path (75) that branches downstream of a pump (10) and upstream of the inlet-side connection portion and allows a refrigerant to flow to a condenser (20) without passing through the inlet-side connection portion or the outlet-side connection portion, wherein in a state in which an evaporator (80) is not connected to the inlet-side connection portion and the outlet-side connection portion, the refrigerant is circulated through the bypass flow path without passing through the inlet-side connection portion and the outlet-side connection portion.

Description

Technical Field

[0004] , , , , , ,

[0001] The present invention relates to a circulation device for a two-phase cooling system and a refrigerant circulation method in the circulation device for a two-phase cooling system. In particular, the present invention relates to a circulation device for a two-phase cooling system that constitutes a two-phase cooling system for circulating a refrigerant by connecting a detachable evaporator, and a refrigerant circulation method in the circulation device for a two-phase cooling system.

Background Art

[0002] Conventionally, a two-phase cooling system that circulates a refrigerant by connecting a detachable evaporator to a connection part is known. Such a circulation device for a two-phase cooling system is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-179375.

[0003] Japanese Patent Application Laid-Open No. 2003-179375 discloses a cooling device (two-phase cooling system) including a plurality of cooling modules that can be selectively attached to an electronic device cabinet. Each cooling module is composed of an evaporative cold plate having an evaporation flow path, a condenser having a condensation flow path, a vapor pipeline, and a liquid pipeline. The working fluid flowing through the cooling module circulates in the order of the evaporation flow path, the vapor pipeline, the condensation flow path, and the liquid pipeline, thereby forming a pressure-fed two-phase cooling cycle. Japanese Patent Application Laid-Open No. 2003-179375 discloses that it is advantageous that the connection part between the inlet of the evaporative cold plate and the liquid pipeline, and the connection part between the outlet of the evaporative cold plate and the vapor pipeline are connected by detachable connection means. That is, Japanese Patent Application Laid-Open No. 2003-179375 discloses a cooling device in which an evaporative cold plate (evaporator) is configured to be detachable from a structure including a condenser, a vapor pipeline, and a liquid pipeline.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In the cooling device described in Japanese Patent Publication No. 2003-179375, the working fluid circulates through an evaporative cold plate, a steam pipeline, a condenser, and a liquid pipeline. Therefore, if the evaporative cold plate is removed from the structure including the condenser, steam pipeline, and liquid pipeline, the working fluid cannot be circulated. In this case, since the working fluid does not flow into the condenser, if the working fluid is circulated at a temperature much lower than the ambient temperature, the temperature of the working fluid will rise due to heat input from the temperature outside the cooling device. As a result, immediately after the evaporative cold plate is removed and then reinstalled, the working fluid will have risen in temperature, preventing the cooled working fluid from flowing into the evaporative cold plate. Therefore, immediately after the evaporative cold plate is reinstalled, the object to be cooled cannot be immediately cooled by the evaporative cold plate. Therefore, it is desirable that, even immediately after the evaporative cold plate (evaporator) has been removed and then reconnected, the cooled, low-temperature working fluid (refrigerant) can be flowed into the evaporative cold plate (evaporator), and that the object to be cooled can be immediately cooled by the evaporative cold plate (evaporator).

[0006] This invention was made to solve the above-mentioned problems, and one object of this invention is to provide a circulation device for a two-phase cooling system and a refrigerant circulation method in a circulation device for a two-phase cooling system that allows cooled, low-temperature refrigerant to flow into the evaporator even immediately after the detachable evaporator has been removed and reconnected, and that allows the object to be cooled by the evaporator to be cooled immediately. [Means for solving the problem]

[0007] The first aspect of this invention provides a circulation device for a two-phase cooling system that circulates a refrigerant by connecting a detachable evaporator. The device comprises a pump for supplying refrigerant, an inlet connection and an outlet connection provided downstream of the pump and connected to the refrigerant inlet and outlet of the evaporator, a condenser for cooling the refrigerant provided downstream of the outlet connection, and a bypass flow path that branches downstream of the pump and upstream of the inlet connection and allows refrigerant to flow to the condenser without passing through the inlet and outlet connections. At least when the evaporator is not connected to the inlet and outlet connections, the device circulates the refrigerant without passing through the inlet and outlet connections and via the bypass flow path.

[0008] A second aspect of this invention relates to a refrigerant circulation method in a circulation device for a two-phase cooling system, which constitutes a two-phase cooling system that circulates a refrigerant by connecting a detachable evaporator, and comprises the steps of: circulating the refrigerant through a bypass channel that allows the refrigerant to flow without passing through the inlet-side connection and the outlet-side connection, when at least the evaporator is not connected to the inlet-side connection connected to the refrigerant inlet and the refrigerant outlet connected to the refrigerant outlet in the evaporator; and cooling the refrigerant that has flowed through the bypass channel and into the condenser. [Effects of the Invention]

[0009] The circulation device for a two-phase cooling system in the first aspect of the present invention, as described above, includes a bypass channel that branches downstream of the pump and upstream of the inlet connection, allowing refrigerant to flow to the condenser without passing through the inlet and outlet connections. At least when the evaporator is not connected to the inlet and outlet connections, the refrigerant is circulated via the bypass channel without passing through the inlet and outlet connections. As a result, even when the detachable evaporator is not connected to the inlet and outlet connections, the refrigerant can be circulated via the bypass channel, allowing the condenser to continuously cool the refrigerant. Therefore, even immediately after the detachable evaporator is removed from the inlet and outlet connections and then reconnected, the cooled, low-temperature refrigerant can flow into the evaporator, and the object to be cooled can be immediately cooled by the evaporator.

[0010] The refrigerant circulation method in a circulation device for a two-phase cooling system in the second aspect of the present invention, as described above, comprises the steps of: circulating refrigerant through a bypass channel that allows refrigerant to flow without passing through the inlet-side connection and the outlet-side connection, when at least the evaporator is not connected to the inlet-side connection and the outlet-side connection in the evaporator; and cooling the refrigerant that has flowed through the bypass channel and into the condenser. As a result, similar to the first aspect described above, even when the detachable evaporator is not connected to the inlet-side connection and the outlet-side connection, refrigerant can be circulated through the bypass channel, allowing the condenser to continuously cool the refrigerant. Therefore, even immediately after the detachable evaporator is reconnected after being removed from the inlet-side connection and the outlet-side connection, cooled refrigerant at a lower temperature can be introduced into the evaporator, and the object to be cooled can be immediately cooled by the evaporator. [Brief explanation of the drawing]

[0011] [Figure 1]This is a schematic diagram showing the configuration of a circulation device for a two-phase cooling system with an evaporator connected, according to the first embodiment. [Figure 2] This is a schematic diagram showing the configuration of a circulation device for a two-phase cooling system according to the first embodiment, with the evaporator not connected. [Figure 3] This is a schematic diagram showing the configuration of a circulation device for a two-phase cooling system according to a first modification of the first embodiment. [Figure 4] This is a schematic diagram showing the configuration of a circulation device for a two-phase cooling system according to a second modification of the first embodiment. [Figure 5] This is a schematic diagram showing the configuration of a circulation device for a two-phase cooling system in a refrigerant recovery state according to the second embodiment. [Figure 6] This is a block diagram showing the control configuration of a circulation device for a two-phase cooling system according to the second embodiment. [Figure 7] This is a graph illustrating the set liquid level according to the second embodiment. [Figure 8] This is a flowchart illustrating the refrigerant recovery process by the control unit according to the second embodiment. [Figure 9] This graph illustrates the change in settings for the third variation. [Figure 10] This is a block diagram showing the control configuration of a circulation device for a two-phase cooling system according to the fourth modified example. [Figure 11] This is a schematic diagram showing an example of notification by the display unit according to the fourth modified example. [Figure 12] This is a schematic diagram showing the configuration of a circulation device for a two-phase cooling system according to the fifth modified example. [Modes for carrying out the invention]

[0012] The following describes embodiments of the present invention based on the drawings.

[0013] [First Embodiment] (Overall configuration of the circulation system for a two-phase cooling system) Referring to FIG. 1, the overall configuration of the circulation device 100 for a two-phase cooling system according to the first embodiment will be described. FIG. 1 shows the circulation device 100 for a two-phase cooling system with a detachable evaporator 80 connected thereto. The circulation device 100 for a two-phase cooling system constitutes a two-phase cooling system 200 that circulates a refrigerant by connecting a detachable evaporator 80. The state with the detachable evaporator 80 connected means, for example, the normal operating state in which the evaporator 80 is attached to the circulation device 100 for a two-phase cooling system and cools the heat source 81 (the object to be cooled). Further, the circulation device 100 for a two-phase cooling system according to the first embodiment is a portable circulation device. Here, "detachable" means that the evaporator 80 directly attached to the circulation device 100 for a two-phase cooling system can be removed from the circulation device 100 for a two-phase cooling system, or the same evaporator 80 as the removed evaporator 80 or another evaporator can be directly attached. Note that two-phase cooling is cooling by a gas-liquid mixed fluid that utilizes the latent heat of vaporization when a liquid changes to a gas.

[0014] In the drawings, the liquid-phase refrigerant 1 is represented by diagonal lines (hatching) from the upper right to the lower left, and the gas-liquid mixed refrigerant 2 is represented by diagonal lines (hatching) from the upper left to the lower right. Further, the refrigerant moves in the direction indicated by the arrow in the circulation device 100 for a two-phase cooling system.

[0015] As shown in FIG. 1, the circulation device 100 for a two-phase cooling system includes a pump 10, a condenser 20, a storage unit 30, an inlet-side connection portion 41 and an outlet-side connection portion 42, an inlet-side opening / closing valve 51 and an outlet-side opening / closing valve 52, a flow rate adjustment portion 60, and a refrigerant flow path 70. The refrigerant flow path 70 includes a first refrigerant flow path 71, a second refrigerant flow path 72, a third refrigerant flow path 73, a fourth refrigerant flow path 74, and a bypass flow path 75. Further, a detachable evaporator 80 is connected to the circulation device 100 for a two-phase cooling system. Note that the "inlet side" in the inlet-side connection portion 41 refers to the inlet side of the evaporator 80, and the "outlet side" in the outlet-side connection portion 42 refers to the outlet side of the evaporator 80. Also, the "inlet side" in the inlet-side opening / closing valve 51 refers to the inlet side of the evaporator 80, and the "outlet side" in the outlet-side opening / closing valve 52 refers to the outlet side of the evaporator 80.

[0016] One end of the first refrigerant flow path 71 is connected to the outlet of the pump 10, and the other end is connected to the inlet-side connection portion 41. A branch portion 76 is formed between one end and the other end of the first refrigerant flow path 71. One end of the second refrigerant flow path 72 is connected to the outlet-side connection portion 42, and the other end is connected to the inlet of the condenser 20. A confluence portion 77 is formed between one end and the other end of the second refrigerant flow path 72. One end of the third refrigerant flow path 73 is connected to the outlet of the condenser 20, and the other end is connected to the inlet of the storage unit 30. One end of the fourth refrigerant flow path 74 is connected to the outlet of the storage unit 30, and the other end is connected to the inlet of the pump 10.

[0017] The bypass flow path 75 branches from the first refrigerant flow path 71 on the downstream side of the pump 10 and on the upstream side of the inlet-side connection portion 41 in the first refrigerant flow path 71, and is configured to allow the refrigerant to flow through the condenser 20 without passing through the inlet-side connection portion 41 and the outlet-side connection portion 42. The bypass flow path 75 branched from the first refrigerant flow path 71 is connected to the second refrigerant flow path 72 on the downstream side of the outlet-side connection portion 42 and on the upstream side of the condenser 20. In the first embodiment, one end of the bypass flow path 75 is connected to the branch portion 76 formed in the first refrigerant flow path 71, and the other end is connected to the confluence portion 77 formed in the second refrigerant flow path 72.

[0018] The refrigerant flow path 70 is formed of a metal material. For example, the refrigerant flow path 70 is made of stainless steel, aluminum, or copper. The refrigerant flow path 70 is formed in a pipe shape.

[0019] Pump 10 is configured to pump liquid-phase refrigerant 1. Pump 10 is operated at a predetermined output range. Pump 10 is configured to pump refrigerant to the evaporator 80 via the first refrigerant flow path 71. Pump 10 is configured to pump refrigerant to the condenser 20 via the first refrigerant flow path 71, the bypass flow path 75, and the second refrigerant flow path 72. Refrigerant flows into Pump 10 from the storage unit 30 via the fourth refrigerant flow path 74. Pump 10 is located downstream of the storage unit 30 in the fourth refrigerant flow path 74 and upstream of the evaporator 80 in the first refrigerant flow path 71. Here, "upstream of Pump 10" refers to the portion upstream of Pump 10 and does not include Pump 10. Also, "downstream of Pump 10" refers to the portion downstream of Pump 10 and does not include Pump 10. The same applies to the upstream and downstream sides of the condenser 20, the upstream and downstream sides of the storage unit 30, and the upstream and downstream sides of the evaporator 80.

[0020] Pump 10 takes in liquid-phase refrigerant 1 from its inlet and discharges liquid-phase refrigerant 1 from its outlet. Pump 10 is a centrifugal pump. However, pump 10 is not limited to a centrifugal pump. Pump 10 may be a mixed-flow pump, an axial-flow pump, or any other known pump. It may also be a positive displacement pump.

[0021] The condenser 20 is configured to produce liquid-phase refrigerant 1 by condensing the gas phase of the gas-liquid mixed refrigerant 2 that flows out of the evaporator 80 when the evaporator 80 is connected. In the first embodiment, the condenser 20 is configured to cool and condense the refrigerant by exchanging heat with a coolant 23 that flows in from the outside. The condenser 20 condenses the refrigerant by, for example, allowing the coolant 23, which flows into the condenser 20 from an external chiller (not shown), to absorb the heat of the refrigerant. The condenser 20 includes a flow path 21 through which the refrigerant flows and a coolant flow path 22 through which the coolant 23 flows. The condenser 20 receives gas-liquid mixed refrigerant 2 from its inlet and discharges liquid-phase refrigerant 1 from its outlet.

[0022] The condenser 20 is located downstream of the outlet connection 42 in the second refrigerant flow path 72. The refrigerant flows into the condenser 20 via the second refrigerant flow path 72. The refrigerant condensed in the condenser 20 flows into the storage section 30 via the third refrigerant flow path 73. The coolant 23 used is a coolant at a lower temperature than the liquid phase refrigerant 1. In the first embodiment, carbon dioxide is used as the refrigerant, and the coolant 23 is a liquid mainly composed of hydrofluoroether. The type of coolant 23 is selected according to the type of refrigerant. The coolant 23 is not particularly limited as long as it is a known coolant.

[0023] The storage section 30 is configured to store liquid-phase refrigerant 1. Furthermore, if there is a gas-liquid mixture of refrigerant 2 that has not been completely condensed in the condenser 20, the storage section 30 is configured to separate the bubbles (gas-phase refrigerant) contained in this gas-liquid mixture and store them in the upper section. The storage section 30 is located downstream of the condenser 20 in the third refrigerant flow path 73. Liquid-phase refrigerant 1 flows into the storage section 30 from its inlet and flows out from its outlet. The storage section 30 is also configured to send liquid-phase refrigerant 1 to the pump 10 via the fourth refrigerant flow path 74.

[0024] The inlet-side connection portion 41 is configured to connect the first refrigerant flow path 71 to the refrigerant inlet in the evaporator 80. The inlet-side connection portion 41 connects the other end of the first refrigerant flow path 71 to the refrigerant inlet provided in the evaporator 80. The inlet-side connection portion 41 is, for example, a joint member that can be attached to and detached from the inlet-side joint member 84 formed at the refrigerant inlet of the evaporator 80. The inlet-side connection portion 41 can be a known joint such as a threaded joint, a flanged joint, a quick joint, or a bite joint. The inlet-side connection portion 41 is provided on the downstream side of the pump 10.

[0025] The outlet-side connection portion 42 is configured to connect the refrigerant outlet in the evaporator 80 to the second refrigerant flow path 72. The outlet-side connection portion 42 connects the refrigerant outlet provided in the evaporator 80 to one end of the second refrigerant flow path 72. The outlet-side connection portion 42 is, for example, a joint member that can be attached to and detached from the outlet-side joint member 85 formed at the refrigerant outlet of the evaporator 80. Known joints such as threaded joints, flanged joints, quick joints, and bite joints can be used for the outlet-side connection portion 42. The outlet-side connection portion 42 is provided downstream of the pump 10 and the evaporator 80, and upstream of the condenser 20.

[0026] The inlet-side on / off valve 51 is provided between the branch section 76 in the first refrigerant flow path 71 and the inlet-side connection section 41. That is, the inlet-side on / off valve 51 is provided between the branch section in the first refrigerant flow path where the bypass flow path 75 branches off from the first refrigerant flow path 71 downstream of the pump 10 and the inlet-side connection section 41. The inlet-side on / off valve 51 is configured to open and close the flow path. For example, the inlet-side on / off valve 51 is an on / off valve that can switch the flow path between a fully open state and a fully closed state. The inlet-side on / off valve 51 may be provided integrally with the inlet-side connection section 41. Alternatively, the inlet-side on / off valve 51 may be provided in the branch section 76.

[0027] The outlet-side on / off valve 52 is provided between the outlet-side connection 42 and the confluence 77 provided in the second refrigerant flow path 72. That is, the outlet-side on / off valve 52 is provided in the second refrigerant flow path between the outlet-side connection 42 and the connection portion downstream of the outlet-side connection 42 to which the bypass flow path 75 is connected. The outlet-side on / off valve 52 is configured to open and close the flow path. The outlet-side on / off valve 52 is, for example, an on / off valve that can switch the flow path between a fully open state and a fully closed state. The outlet-side on / off valve 52 may be provided integrally with the outlet-side connection 42. Alternatively, the outlet-side on / off valve 52 may be provided in the confluence 77.

[0028] The flow rate adjustment unit 60 is provided in the bypass flow path 75. The flow rate adjustment unit 60 is configured to increase the pressure loss in the bypass flow path 75 by reducing the cross-sectional area of ​​a portion of the bypass flow path 75. In the first embodiment, the flow rate adjustment unit 60 is an orifice 61. The bore diameter of the orifice 61 is preset to adjust the distribution between the refrigerant flow rate into the evaporator 80 and the refrigerant flow rate into the bypass flow path 75 when the evaporator 80 is connected. In the first embodiment, the bore diameter of the orifice 61 is set such that the refrigerant flow rate into the evaporator 80 is greater than the refrigerant flow rate into the bypass flow path 75.

[0029] As shown in Figure 1, in the circulation device 100 for a two-phase cooling system, an evaporator 80 is connected to the inlet connection 41 and the outlet connection 42. The evaporator 80 cools the heat source 81 by utilizing the heat of vaporization when a portion of the liquid-phase refrigerant 1 supplied via the inlet connection 41 evaporates and changes into a gas-liquid mixture of refrigerant 2. The evaporator 80 includes a cold plate 82 and a refrigerant flow path 83 provided inside the cold plate 82. The inlet connection 41 is connected to the refrigerant inlet of the refrigerant flow path 83, and the outlet connection 42 is connected to the refrigerant outlet. The heat source 81 is installed on one side of the cold plate 82. The evaporator 80 and the heat source 81 are integrally formed. Note that the refrigerant flow path 83 shown in Figure 1 is schematic. The refrigerant flow path 83 may have a structure that bends multiple times inside the evaporator 80 in order to perform heat exchange efficiently. Furthermore, the refrigerant flow path 83 may be configured to split into multiple paths at the inlet, pass through the inside of the evaporator 80, and merge into one path at the outlet. The structure of the evaporator 80 is not particularly limited.

[0030] In the first embodiment, the refrigerant is carbon dioxide. However, the type of refrigerant is not limited to this. The refrigerant may be, for example, chlorofluorocarbon (CFC) or ammonia.

[0031] Figure 2 shows the circulation device 100 for a two-phase cooling system with the detachable evaporator 80 not connected. The state with the detachable evaporator 80 not connected means, for example, that the evaporator 80 has been removed from the circulation device 100 for the two-phase cooling system due to maintenance of the heat source 81 or the evaporator 80. In the circulation device 100 for a two-phase cooling system with the evaporator 80 not connected, the inlet valve 51 and the outlet valve 52 are in the closed state.

[0032] The condenser 20 is configured to cool the liquid-phase refrigerant 1 sent from the pump 10 via the bypass channel 75 when the evaporator 80 is not connected. When the evaporator 80 is not connected, the condenser 20 allows the liquid-phase refrigerant 1 to flow in from the inlet of the condenser 20 and discharges the cooled liquid-phase refrigerant 1 from the outlet of the condenser 20. The other configurations of the circulation device 100 for the two-phase cooling system when the evaporator 80 is not connected are the same as those of the circulation device 100 for the two-phase cooling system when the evaporator 80 is connected, as described with reference to Figure 1, so their description is omitted.

[0033] (Refrigerant circulation) Referring to Figure 1, the circulation of refrigerant within the two-phase cooling system circulation device 100 will be explained with the evaporator 80 connected to the inlet connection 41 and the outlet connection 42.

[0034] Liquid-phase refrigerant 1 is supplied from pump 10. The refrigerant flows through the first refrigerant flow path 71. At the branching point 76 of the first refrigerant flow path 71, a portion of the refrigerant flows through the fully open inlet-side on / off valve 51 and inlet-side connection point 41 and flows into the evaporator 80. The remaining portion of the refrigerant flows into the bypass flow path 75, as will be described later. A portion of the liquid-phase refrigerant 1 that has flowed into the evaporator 80 evaporates and changes into a gas-liquid mixture of refrigerant 2. The gas-liquid mixture of refrigerant 2 flows from the evaporator 80 through the outlet-side connection point 42 into the second refrigerant flow path 72. The gas-liquid mixture of refrigerant 2 that has flowed into the second refrigerant flow path 72 flows through the fully open outlet-side on / off valve 52 and confluence point 77. At the confluence point 77, the gas-liquid mixture of refrigerant 2 merges with the liquid-phase refrigerant 1 that has flowed in from the bypass flow path 75. The combined gas-liquid mixture refrigerant 2 and the liquid-phase refrigerant 1 flowing in from the bypass channel 75 enter the condenser 20 in a gas-liquid mixture state. The gaseous refrigerant of the gas-liquid mixture refrigerant 2 that enters the condenser 20 is condensed and changed into liquid-phase refrigerant 1. The condensed liquid-phase refrigerant 1 flows from the condenser 20 through the third refrigerant channel 73 and into the storage unit 30. The refrigerant that enters the storage unit 30 flows through the fourth refrigerant channel 74 and into the pump 10.

[0035] Furthermore, at the branching point 76 of the first refrigerant flow path 71, the remaining liquid-phase refrigerant 1 flows into the bypass flow path 75. The refrigerant that flows into the bypass flow path 75 flows through the orifice 61 provided in the bypass flow path 75 and flows into the confluence point 77 of the second refrigerant flow path 72. At the confluence point 77, the liquid-phase refrigerant 1 that flowed in from the bypass flow path 75 merges with the gas-liquid mixed refrigerant 2.

[0036] Next, referring to Figure 2, the circulation of refrigerant within the two-phase cooling system circulation device 100 will be explained when the evaporator 80 is not connected to the inlet connection 41 and the outlet connection 42.

[0037] When the evaporator 80 is not connected, the inlet valve 51 and the outlet valve 52 are fully closed to prevent liquid-phase refrigerant 1 from flowing out from the inlet connection 41 and gas-liquid mixed refrigerant 2 from flowing out from the outlet connection 42. As a result, unlike when the evaporator 80 is connected to the inlet connection 41 and the outlet connection 42, at the branch 76 of the first refrigerant flow path 71, the liquid-phase refrigerant 1 flows into the bypass flow path 75, except for the refrigerant that has flowed between the branch 76 and the inlet valve 51. Also, at the junction 77 of the second refrigerant flow path 72, the liquid-phase refrigerant 1 flowing in from the bypass flow path 75 flows through the second refrigerant flow path 72 and into the condenser 20.

[0038] Liquid-phase refrigerant 1 is supplied from pump 10. The liquid-phase refrigerant 1 flows through the first refrigerant flow path 71. At the branching point 76 of the first refrigerant flow path 71, the liquid-phase refrigerant 1 flows into the bypass flow path 75. The liquid-phase refrigerant 1 that has flowed into the bypass flow path 75 flows through the orifice 61 provided in the bypass flow path 75 and flows into the confluence point 77 of the second refrigerant flow path 72. The liquid-phase refrigerant 1 that has flowed into the confluence point 77, except for the amount that has flowed between the confluence point 77 and the outlet-side on / off valve 52, flows through the second refrigerant flow path 72 and flows into the condenser 20. The liquid-phase refrigerant 1 that has flowed into the condenser 20 is cooled or maintains a cooled state. The liquid-phase refrigerant 1 flows from the condenser 20 through the third refrigerant flow path 73 and flows into the storage section 30. The refrigerant that flows into the storage section 30 flows through the fourth refrigerant passage 74 and into the pump 10.

[0039] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0040] In the first embodiment, as described above, a bypass channel 75 is provided that branches downstream of the pump 10 and upstream of the inlet connection 41, allowing refrigerant to flow to the condenser 20 without passing through the inlet connection 41 and the outlet connection 42. At least when the evaporator 80 is not connected to the inlet connection 41 and the outlet connection 42, the refrigerant is circulated via the bypass channel 75 without passing through the inlet connection 41 and the outlet connection 42. As a result, even when the detachable evaporator 80 is not connected to the inlet connection 41 and the outlet connection 42, the liquid phase refrigerant 1 can be circulated via the bypass channel 75, allowing the condenser 20 to continuously cool the liquid phase refrigerant 1. Therefore, even immediately after the detachable evaporator 80 is removed from the inlet connection 41 and the outlet connection 42 and then reconnected, the cooled, low-temperature liquid phase refrigerant 1 can flow into the evaporator 80, and the heat source 81 can be immediately cooled by the evaporator 80.

[0041] Furthermore, in the first embodiment, as described above, the refrigerant circulation method includes the steps of: circulating the refrigerant through a bypass channel 75 that allows the refrigerant to flow without passing through the inlet-side connection 41 and the outlet-side connection 42, at least when the evaporator 80 is not connected to the inlet-side connection 41 and the outlet-side connection 42; and cooling the refrigerant that has flowed through the bypass channel 75 and into the condenser 20. As a result, even when the detachable evaporator 80 is not connected to the inlet-side connection 41 and the outlet-side connection 42, the liquid-phase refrigerant 1 can be circulated through the bypass channel 75, and the condenser 20 can continuously cool the liquid-phase refrigerant 1. Therefore, even immediately after the detachable evaporator 80 is removed from the inlet-side connection 41 and the outlet-side connection 42 and then reconnected, the cooled, low-temperature liquid-phase refrigerant 1 can be flowed into the evaporator 80, and the heat source 81 can be immediately cooled by the evaporator 80.

[0042] Furthermore, in the first embodiment, the following additional effects can be obtained by configuring it as described below.

[0043] In other words, in the first embodiment, as described above, in the normal operating state in which the evaporator 80 is connected to the inlet connection 41 and the outlet connection 42, a portion of the refrigerant is circulated through the evaporator 80, and the remaining portion of the refrigerant is circulated through the bypass passage 75. As a result, even if the refrigerant cannot be circulated through the evaporator 80 due to blockage of the evaporator 80 in the normal operating state in which the evaporator 80 is connected to the inlet connection 41 and the outlet connection 42, the liquid phase refrigerant 1 can be circulated through the bypass passage 75. Therefore, it is possible to suppress the occurrence of malfunctions in the two-phase cooling system circulation device 100 caused by a pressure increase at the outlet of the pump 10 due to the inability to circulate the refrigerant.

[0044] Furthermore, in the first embodiment, as described above, a flow rate adjustment unit 60 is provided in the bypass flow path 75. The flow rate adjustment unit 60 can reduce the cross-sectional area of ​​a portion of the bypass flow path 75, thereby increasing the pressure loss in the bypass flow path 75. This makes it possible to reduce the refrigerant flow rate into the bypass flow path 75 when the evaporator 80 is connected. Therefore, when the evaporator 80 is connected, the refrigerant flow rate into the evaporator 80 and the refrigerant flow rate into the bypass flow path 75 can be adjusted so that the refrigerant flow rate into the evaporator 80 is greater than the refrigerant flow rate into the bypass flow path 75.

[0045] Furthermore, in the first embodiment, as described above, the flow rate adjustment unit 60 is an orifice 61 that adjusts the flow rate of the refrigerant flowing through the bypass passage 75. The orifice 61 can increase the pressure loss in the bypass passage 75, thereby reducing the flow rate of refrigerant flowing into the bypass passage 75. Therefore, in the branching unit 76, the flow rate of the liquid phase refrigerant 1 flowing into the evaporator 80 and the flow rate of the liquid phase refrigerant 1 flowing into the bypass passage 75 can be adjusted with a simple configuration so that the flow rate of refrigerant flowing into the evaporator 80 is greater than the flow rate of refrigerant flowing into the bypass passage 75.

[0046] Furthermore, in the first embodiment, as described above, the condenser 20 is configured to cool either the gaseous phase refrigerant contained in the gas-liquid mixture refrigerant 2 by condensing it with a coolant 23 flowing in from the outside, or to cool the liquid phase refrigerant 1 of the refrigerant. Since the gaseous phase refrigerant contained in the gas-liquid mixture refrigerant 2 and the liquid phase refrigerant 1 are cooled by the coolant 23 flowing in from the outside, it is possible to achieve both a simplified configuration of the condenser 20 and reliable cooling of the refrigerant.

[0047] Furthermore, in the first embodiment, as described above, the bypass flow path 75 branches downstream of the pump 10 and upstream of the inlet connection 41, and is connected downstream of the outlet connection 42 and upstream of the condenser 20. As a result, the bypass flow path 75 is not directly connected to the condenser 20, but is connected to the flow path between the outlet connection 42 and the condenser 20. Therefore, since multiple refrigerant flow paths are not connected to the condenser 20, the configuration of the condenser 20 can be further simplified. Therefore, the size of the circulation device 100 for the two-phase cooling system can be further suppressed.

[0048] Furthermore, in the first embodiment, as described above, an inlet-side on / off valve 51 is provided between the branching portion where the bypass flow path 75 branches downstream of the pump 10 and the inlet-side connection portion 41 to open and close the refrigerant flow path, and an outlet-side on / off valve 52 is provided between the outlet-side connection portion 42 and the connection portion where the bypass flow path 75 is connected downstream of the outlet-side connection portion 42 to open and close the refrigerant flow path. As a result, when the evaporator 80 is not connected, the inlet-side on / off valve 51 and the outlet-side on / off valve 52 are fully closed, which prevents liquid-phase refrigerant 1 from flowing out of the inlet-side connection portion 41 and gas-liquid mixed refrigerant 2 from flowing out of the outlet-side connection portion 42. In addition, when the evaporator 80 is removed from the inlet-side connection portion 41 and the outlet-side connection portion 42, the inlet-side on / off valve 51 and the outlet-side on / off valve 52 are fully closed before removing the evaporator 80, so that the liquid-phase refrigerant 1 circulating through the bypass flow path 75 can be cooled by the condenser 20 without stopping the condenser 20. Therefore, even immediately after the detachable evaporator 80 is connected to the inlet connection 41 and the outlet connection 42, properly cooled refrigerant can be introduced into the evaporator 80, and the heat source 81 can be cooled more immediately by the evaporator 80.

[0049] Furthermore, in the first embodiment, as described above, a storage unit 30 is provided downstream of the condenser 20 and upstream of the pump 10. This allows the storage unit 30 to separate the bubbles (gas-phase refrigerant) contained in the gas-liquid mixture refrigerant 2 that has not been completely condensed in the condenser 20, thereby sending only the liquid-phase refrigerant 1 to the pump 10. Therefore, it is possible to suppress the occurrence of malfunctions in the pump 10 caused by bubbles (gas-phase refrigerant) contained in the refrigerant.

[0050] Furthermore, in the first embodiment, as described above, with the evaporator 80 connected to the inlet-side connection 41 and the outlet-side connection 42, the gas-liquid mixed refrigerant 2 that flows out of the evaporator 80 flows into the condenser 20. As a result, the gas-liquid mixed refrigerant 2 flows out of the evaporator 80 without completely evaporating the liquid-phase refrigerant 1 in the evaporator 80, thus preventing insufficient cooling of the heat source utilizing the latent heat of vaporization in the evaporator 80.

[0051] [Second Embodiment] Referring to Figures 5 to 8, the overall configuration of the circulation device 300 for a two-phase cooling system according to the second embodiment and the refrigerant recovery method for recovering refrigerant from the evaporator 80 will be described.

[0052] For example, when performing maintenance on an evaporator attached to a circulation device for a two-phase cooling system, the evaporator attached to the circulation device is removed from the circulation device. When removing the evaporator from the circulation device, if liquid phase refrigerant is accumulating in the refrigerant flow path inside the evaporator, this may result in refrigerant loss due to vaporization and leakage, or freezing due to the heat of vaporization. Therefore, in order to reduce the amount of refrigerant accumulating inside the evaporator when removing it from the circulation device, it is necessary to recover the refrigerant accumulating in the refrigerant flow path inside the evaporator into a storage unit before removing the evaporator from the circulation device.

[0053] (Overall configuration of the circulation system for a two-phase cooling system) Referring to Figures 5 and 6, the overall configuration of the circulation device 300 for a two-phase cooling system according to the second embodiment will be described. Figure 5 shows the circulation device 300 for a two-phase cooling system in the refrigerant recovery state when recovering refrigerant from the evaporator 80. In the refrigerant recovery state, the evaporator 80 of the circulation device 300 is connected to the inlet-side connection part 41 and the outlet-side connection part 42, with the inlet-side on / off valve 51 in the closed state and the outlet-side on / off valve 52 in the open state. Components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0054] The circulation device 300 for a two-phase cooling system according to the second embodiment further includes an inlet valve opening / closing mechanism 53, an outlet valve opening / closing mechanism 54, a detection unit 31, and a control device 90 (see Figure 6) compared to the circulation device 100 for a two-phase cooling system according to the first embodiment.

[0055] The inlet valve opening / closing mechanism 53 is configured to switch between the open and closed states of the inlet valve 51. The inlet valve opening / closing mechanism 53 includes, for example, a motor. The inlet valve opening / closing mechanism 53 is connected to the control unit 91 (see Figure 6). The inlet valve 51 is opened and closed by the inlet valve opening / closing mechanism 53 under the control of the control unit 91.

[0056] The outlet valve opening / closing mechanism 54 is configured to switch between the open and closed states of the outlet valve 52. The outlet valve opening / closing mechanism 54 includes, for example, a motor. The outlet valve opening / closing mechanism 54 is connected to the control unit 91 (see Figure 6). The outlet valve 52 is opened and closed by the outlet valve opening / closing mechanism 54 under the control of the control unit 91. The configuration of the inlet valve opening / closing mechanism 53 and the outlet valve opening / closing mechanism 54 is not particularly limited as long as they are known valve opening / closing mechanisms.

[0057] The detection unit 31 is configured to detect the amount of refrigerant recovered. Specifically, the detection unit 31 is configured to detect the amount of refrigerant stored in the storage unit 30 as the amount of refrigerant recovered. The detection unit 31 is, for example, a liquid level sensor and measures the liquid level 3 (see Figure 7) of the liquid phase refrigerant stored in the storage unit 30.

[0058] As shown in Figure 6, the control device 90 comprises a control unit 91 and a storage unit 92. The control unit 91 is configured to stop the operation of the pump 10 and terminate the refrigerant recovery process based on the detection result from the detection unit 31. The control unit 91 is also configured to close the outlet-side on-off valve 52 using the outlet-side on-off valve opening / closing mechanism 54 based on the detection result from the detection unit 31, thereby preventing the outflow of refrigerant from the outlet-side on-off valve 52 to the outlet-side connection unit 42. The control unit 91 is composed of a processor such as a CPU (Central Processing Unit). The storage unit 92 is composed of a volatile storage device and a non-volatile storage device. The storage unit 92 stores the set storage amount of refrigerant in the storage unit 30 (described later) and a program for setting the set storage amount. The set storage amount includes the set liquid level 5 (see Figure 7), which will be described later. The program for setting the set storage amount includes a program for setting the set liquid level 5. The volatile storage device is used for temporary storage when the control unit 91 performs calculations.

[0059] (Refrigerant circulation during refrigerant recovery from the evaporator) Referring to Figure 5, the circulation of the refrigerant when recovering it from the evaporator 80 connected to the two-phase cooling system circulation device 300 will be explained.

[0060] In the circulating device 300 for a two-phase cooling system in a refrigerant recovery state, the evaporator 80 is connected to the inlet connection 41 and the outlet connection 42. The inlet on / off valve 51 is in the closed state, and the outlet on / off valve 52 is in the open state. The heat source 81 is not generating heat.

[0061] Liquid-phase refrigerant 1 is supplied from pump 10. The liquid-phase refrigerant 1 flows through the first refrigerant flow path 71. Since the inlet valve 51 is fully closed, at the branching point 76 of the first refrigerant flow path 71, the liquid-phase refrigerant 1, except for that which has flowed between the branching point 76 and the inlet valve 51, flows into the bypass flow path 75. The liquid-phase refrigerant 1 that has flowed into the bypass flow path 75 flows into the confluence point 77 of the second refrigerant flow path 72. The liquid-phase refrigerant 1 that has flowed into the confluence point 77 flows through the second refrigerant flow path 72 and flows into the condenser 20. The refrigerant that has flowed into the condenser 20 flows through the third refrigerant flow path 73 and flows into the storage unit 30. The refrigerant that has flowed into the storage unit 30 flows through the fourth refrigerant flow path 74 and flows into pump 10.

[0062] Liquid-phase refrigerant 1 is not supplied to the evaporator 80 from the pump 10. Therefore, in the refrigerant recovery state, liquid-phase refrigerant 1 circulating in the two-phase cooling system circulation device 300 does not flow into the evaporator 80. Immediately after the inlet-side on / off valve 51 is fully closed, liquid-phase refrigerant 1 remains in the refrigerant flow path 83 inside the evaporator 80. Although the heat source 81 is not generating heat, the temperature inside the evaporator 80 rises due to heat from the outside air. As the temperature inside the evaporator 80 rises, the temperature and pressure of the liquid-phase refrigerant 1 remaining in the evaporator 80 increase, and some of the liquid-phase refrigerant 1 evaporates and changes into a gas-liquid mixture of refrigerant 2.

[0063] Here, the liquid-phase refrigerant 1 supplied from the pump 10 flows from the bypass channel 75 into the confluence 77 of the second refrigerant channel 72, and circulates through the second refrigerant channel 72, the condenser 20, the third refrigerant channel 73, the storage section 30, and the fourth refrigerant channel 74. This circulating liquid-phase refrigerant 1 is cooled or maintained in a cooled state by the condenser 20. Therefore, the pressure of the gas phase refrigerant in the gas-liquid mixture refrigerant 2 remaining in the evaporator 80 is greater than the pressure of the liquid-phase refrigerant 1 circulating in the two-phase cooling system circulation device 300. In other words, the pressure difference between the pressure of the gas phase refrigerant contained in the gas-liquid mixture refrigerant 2 in the evaporator 80 and the pressure of the liquid-phase refrigerant 1 circulating in the path from the confluence 77 of the second refrigerant channel 72 through the condenser 20, the storage section 30, the pump 10, and the bypass channel 75 becomes large. Due to this pressure difference, the gas-liquid mixture refrigerant 2 in the evaporator 80 flows out of the evaporator 80 toward the confluence 77 of the second refrigerant flow path 72. Specifically, the gas phase of the gas-liquid mixture refrigerant 2 in the evaporator 80 flows out of the evaporator 80 toward the confluence 77 of the second refrigerant flow path 72, while simultaneously pushing out the liquid phase of the gas-liquid mixture refrigerant 2 in the evaporator 80. At the confluence 77, the gas-liquid mixture refrigerant 2 that has flowed out of the evaporator 80 merges with the liquid phase refrigerant 1 that has flowed in from the bypass flow path 75, and the gas phase refrigerant contained in the merged gas-liquid mixture refrigerant 2 is condensed. The liquid phase refrigerant 1 after the merge flows through the second refrigerant flow path 72 and flows into the condenser 20. In other words, the gas-liquid mixture refrigerant 2 in the evaporator 80 flows through the second refrigerant flow path 72 and is led to the condenser 20.

[0064] As a result, any refrigerant remaining in the refrigerant flow path inside the evaporator 80 is recovered into the storage unit 30. However, since it is not possible to create a vacuum in the flow path 83 inside the evaporator 80, it is not possible to recover all of the refrigerant inside the evaporator 80. Nevertheless, it is possible to reduce the amount of refrigerant remaining inside the evaporator 80 when removing the evaporator 80 from the circulation device 300 for the two-phase cooling system.

[0065] (Control of the termination of the refrigerant recovery process by the control unit based on the detection results of the detection unit) Referring to Figure 7, the control of the refrigerant recovery process termination by the control unit 91 based on the detection results of the detection unit 31 will be explained.

[0066] In the refrigerant recovery state, when the amount of refrigerant stored detected by the detection unit 31 while the refrigerant is circulating through the bypass channel 75 without passing through the evaporator 80 exceeds a preset storage amount, the control unit 91 is configured to close the outlet-side on / off valve 52 to prevent refrigerant from flowing out from the outlet-side on / off valve 52 to the outlet-side connection part 42, and to stop the operation of the pump 10 to terminate the refrigerant recovery process. The preset storage amount includes the preset liquid level 5. The amount of refrigerant stored also includes the refrigerant liquid level 3.

[0067] First, as shown in Figure 2, before the evaporator 80 is connected to the two-phase cooling system circulation device 300, the refrigerant is circulated via the bypass channel 75, without going through the inlet connection 41 and the outlet connection 42. That is, the refrigerant circulates within the two-phase cooling system circulation device 300 while the evaporator 80 is not connected to the inlet connection 41 and the outlet connection 42. At this time, the detection unit 31 (see Figure 5) measures the liquid level of the liquid phase refrigerant 1 stored in the storage unit 30.

[0068] Here, in the refrigerant recovery state, if the liquid level 3 (see Figure 7) of the liquid-phase refrigerant 1 stored in the storage unit 30 becomes equal to the liquid level of the liquid-phase refrigerant 1 stored in the storage unit 30 when the evaporator 80 is not connected, it can be said that the refrigerant remaining in the evaporator 80 has been recovered into the storage unit 30. However, as described above, it is not possible to recover all of the refrigerant in the evaporator 80. Therefore, as shown in Figure 7, a set liquid level 5 is set based on the liquid level 4 of the liquid-phase refrigerant 1 stored in the storage unit 30 when the evaporator 80 is not connected. The set liquid level 5 is the liquid level of the liquid-phase refrigerant 1 stored in the storage unit 30 in the refrigerant recovery state, which is set by subtracting the margin, such as the amount of refrigerant that cannot be recovered in the evaporator 80, from the liquid level 4 of the liquid-phase refrigerant 1 stored in the storage unit 30 when the evaporator 80 is not connected. Therefore, when the liquid level of the liquid phase refrigerant stored in the storage unit 30 reaches the set liquid level 5 or higher in the refrigerant recovery state, it can be considered that the refrigerant remaining in the evaporator 80 has been recovered into the storage unit 30.

[0069] The set liquid level 5 is set by the control unit 91. Specifically, the control unit 91 obtains the liquid level 4 of the liquid phase refrigerant 1 stored in the storage unit 30 when the evaporator 80 is not connected, as detected by the detection unit 31, and sets the set liquid level 5 by executing a program for setting the set liquid level 5 stored in the memory unit 92. The set liquid level 5 is stored in the memory unit 92.

[0070] For example, when removing the evaporator 80 from the two-phase cooling system circulation device 300 for maintenance of the evaporator 80, the refrigerant is recovered from the evaporator 80 before removal. That is, starting from the state shown in Figure 1, where the evaporator 80 is connected to the inlet connection part 41 and the outlet connection part 42, and the inlet on-off valve 51 and the outlet on-off valve 52 are open, and the heat source 81 is being cooled by the evaporator 80, the refrigerant is circulated via the bypass flow path 75 without going through the evaporator 80, in the refrigerant recovery state shown in Figure 5, where the evaporator 80 is connected to the inlet connection part 41 and the outlet connection part 42, the inlet on-off valve 51 is closed, and the outlet on-off valve 52 is open. In the refrigerant recovery state, the heat generation of the heat source 81 is stopped. At this time, the detection unit 31 measures the liquid level 3 (see Figure 7) of the liquid phase refrigerant 1 stored in the storage unit 30 in the refrigerant recovery state.

[0071] The control unit 91 acquires the liquid level 3 of the liquid phase refrigerant 1 stored in the storage unit 30, which is detected by the detection unit 31. As shown in Figure 7, as time t progresses, the liquid level h (liquid level 3) of the liquid phase refrigerant 1 stored in the storage unit 30 rises. . Inspect When the liquid level 3 of the liquid-phase refrigerant 1 detected by the outlet 31 reaches or exceeds a preset liquid level 5 (time t1), the control unit 91 controls the outlet side on-off valve 52 to prevent the refrigerant from flowing out from the outlet side on-off valve 52 to the outlet side connection 42, and also controls the pump 10 to stop operation and end the refrigerant recovery process.

[0072] (Refrigerant recovery process by the control unit) Referring to Figure 8, the refrigerant recovery process by the control unit 91 according to the second embodiment will be described. Note that the order of the processing steps can be reversed or executed simultaneously, as long as they do not contradict each other.

[0073] In step S1, with the evaporator 80 connected, the inlet valve 51 and outlet valve 52 open, and the heat source 81 being cooled by the evaporator 80, after the heat generation of the heat source 81 stops, the control unit 91 closes the inlet valve 51 using the inlet valve opening / closing mechanism 53 to enter a refrigerant recovery state. In the refrigerant recovery state, the refrigerant is circulated through the bypass channel 75 without passing through the evaporator 80. The process then proceeds to step S2.

[0074] In step S2, the control unit 91 obtains the liquid level 3 of the liquid-phase refrigerant 1 stored in the storage unit 30, which is detected by the detection unit 31. The process then proceeds to step S3.

[0075] In step S3, the control unit 91 determines that if the liquid level 3 of the acquired liquid phase refrigerant 1 is equal to or greater than the set liquid level 5 (Yes in step S3), the process proceeds to step S4; otherwise, the process proceeds to step S2.

[0076] In step S4, the control unit 91 closes the outlet valve 52 using the outlet valve opening / closing mechanism 54. The process then proceeds to step S5.

[0077] In step S5, the control unit 91 stops the operation of the pump 10. After that, the refrigerant recovery process is completed.

[0078] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0079] In the second embodiment, as described above, the bypass flow path 75 branches off at the branching section 7 downstream of the pump 10. 6 andThe system further includes an inlet-side shut-off valve 51 provided between the inlet-side connection 41 and the outlet-side connection 42, which opens and closes the flow path of the refrigerant. When recovering refrigerant from the evaporator 80, the evaporator 80 is connected to the inlet-side connection 41 and the outlet-side connection 42, and in a refrigerant recovery state where the inlet-side shut-off valve 51 is closed, the refrigerant is circulated via the bypass flow path 75 without passing through the evaporator 80, and the refrigerant from the evaporator 80 is guided to the condenser 20. Because the inlet-side shut-off valve 51 is closed, the circulating liquid-phase refrigerant 1 does not flow into the evaporator 80, and the evaporator 80 is heated by the outside air, causing the temperature inside the evaporator 80 to rise. As a result, the temperature and pressure of the liquid-phase refrigerant 1 remaining in the evaporator 80 rise, and a portion of the liquid-phase refrigerant 1 in the evaporator 80 evaporates and changes into a gas-liquid mixture of refrigerant 2. As a result, a pressure difference is created between the pressure of the gas phase refrigerant contained in the gas-liquid mixed refrigerant 2 in the evaporator 80 and the pressure of the liquid phase refrigerant 1 circulating in the path from the confluence 77 of the second refrigerant flow path 72 through the condenser 20, storage section 30, pump 10, and bypass flow path 75. This allows the gas-liquid mixed refrigerant 2 in the evaporator 80 to flow out from the evaporator 80 towards the confluence 77 of the second refrigerant flow path 72. Furthermore, since the liquid phase refrigerant 1 in the evaporator 80 can be converted into a gas-liquid mixed refrigerant 2 by the rise in the internal temperature of the evaporator 80, there is no need to install additional equipment such as heaters to convert it into a gas-liquid mixed refrigerant 2. For these reasons, an increase in the number of parts and structural complexity can be suppressed, and refrigerant accumulating in the refrigerant flow path 83 inside the evaporator 80 can be easily recovered.

[0080] Furthermore, in the second embodiment, as described above, the system further includes a detection unit 31 for detecting the amount of refrigerant recovered, and a control unit 91 that stops the operation of the pump 10 and terminates the refrigerant recovery process based on the detection result from the detection unit 31. This allows the termination of the refrigerant recovery process to be based on the detection result from the detection unit 31 for detecting the amount of refrigerant recovered. Therefore, the refrigerant recovery process can be reliably performed based on the detection result from the detection unit 31 for detecting the amount of refrigerant recovered.

[0081] Furthermore, in the second embodiment, as described above, a storage unit 30 is provided downstream of the condenser 20 and upstream of the pump 10, and the detection unit 31 detects the amount of refrigerant stored in the storage unit 30 as the amount of refrigerant recovered. As a result, the operation of the pump 10 can be stopped and the refrigerant recovery process can be terminated based on the detection result of the amount of refrigerant stored in the storage unit 30 as the amount of refrigerant recovered. Therefore, since the detection result of the amount of refrigerant recovered can be obtained with a simple configuration of the detection unit 31, the complexity of the structure of the circulation device 300 for the two-phase cooling system can be suppressed.

[0082] Furthermore, in the second embodiment, as described above, when the amount of refrigerant stored by the detection unit 31 while the refrigerant is circulating through the bypass channel 75 without passing through the evaporator 80 in the refrigerant recovery state exceeds a preset storage amount, the control unit 91 controls the operation of the pump 10 to terminate the refrigerant recovery process. This makes it easier to detect that the refrigerant remaining in the evaporator 80 has been recovered into the storage unit 30 based on the preset storage amount. Therefore, the refrigerant recovery process can be performed more easily and reliably based on the preset storage amount.

[0083] Furthermore, in the second embodiment, as described above, an outlet-side on / off valve 52 is provided between the outlet-side connection part 42 and the connection part downstream of the outlet-side connection part 42 to which the bypass flow path 75 is connected, and which opens and closes the flow path of the refrigerant. Based on the detection result by the detection unit 31, the control unit 91 controls the outlet-side on / off valve 52 to close and prevent the outflow of refrigerant from the outlet-side on / off valve 52 to the outlet-side connection part 42. This prevents the outflow of refrigerant from the outlet-side on / off valve 52 to the outside when, for example, the evaporator 80 is removed from the circulation device 300 for the two-phase cooling system, thereby suppressing the need for additional refrigerant charging.

[0084] Furthermore, in the second embodiment, as described above, the refrigerant circulation method further includes the steps of: when recovering refrigerant from the evaporator 80, the evaporator 80 is connected to the inlet connection 41 and the outlet connection 42, and the inlet on-off valve 51 provided between the branching section 76 where the bypass flow path 75 branches and the inlet connection 41 is closed, circulating the refrigerant via the bypass flow path 75 without going through the evaporator 80 and guiding the refrigerant from the evaporator 80 to the condenser 20; and stopping the circulation of the refrigerant and ending the refrigerant recovery process based on the detection result of the amount of refrigerant recovered. Because the inlet on-off valve 51 is closed, the circulating liquid phase refrigerant 1 does not flow into the evaporator 80, and the evaporator 80 is heated by outside air, so the temperature inside the evaporator 80 rises. As a result, the temperature and pressure of the liquid phase refrigerant 1 remaining in the evaporator 80 rise, and a portion of the liquid phase refrigerant 1 evaporates and changes into a gas-liquid mixture refrigerant 2. As a result, a pressure difference is created between the pressure of the gas phase refrigerant contained in the gas-liquid mixed refrigerant 2 in the evaporator 80 and the pressure of the liquid phase refrigerant 1 circulating in the path from the confluence 77 of the second refrigerant flow path 72 through the condenser 20, storage section 30, pump 10, and bypass flow path 75. This allows the gas-liquid mixed refrigerant 2 in the evaporator 80 to flow out from the evaporator 80 towards the confluence 77 of the second refrigerant flow path 72. Furthermore, since the liquid phase refrigerant 1 in the evaporator 80 can be converted into a gas-liquid mixed refrigerant 2 by the rise in the internal temperature of the evaporator 80, there is no need to install additional equipment such as heaters to convert it into a gas-liquid mixed refrigerant 2. For these reasons, an increase in the number of parts and structural complexity can be suppressed, and refrigerant accumulating in the refrigerant flow path 83 inside the evaporator 80 can be easily recovered.

[0085] [Differentiation] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope of the claims.

[0086] For example, in the first embodiment described above, an example was shown in which the flow rate adjustment unit 60 is provided in the bypass flow path 75, but the present invention is not limited thereto. For example, as shown in the first modified example in Figure 3, the flow rate adjustment unit 60 does not have to be provided in the bypass flow path 75. If the flow rate adjustment unit 60 is not provided in the bypass flow path 75, the adjustment of the distribution between the refrigerant flow rate flowing into the evaporator 80 and the refrigerant flow rate flowing into the bypass flow path 75 when the evaporator 80 is connected can be done, for example, by the pipe diameter or flow path length of the bypass flow path 75.

[0087] Furthermore, although the first embodiment described above shows an example in which the refrigerant flow rate into the evaporator 80 is greater than the refrigerant flow rate into the bypass channel 75, the present invention is not limited to this. For example, the refrigerant flow rate into the evaporator 80 may be configured to be equal to the refrigerant flow rate into the bypass channel 75, or the refrigerant flow rate into the evaporator 80 may be configured to be less than the refrigerant flow rate into the bypass channel 75.

[0088] Furthermore, although the first embodiment described above shows an example where the flow rate adjustment section 60 is an orifice 61, the present invention is not limited thereto. For example, as shown in the second modified example in Figure 4, the flow rate adjustment section 60 may be a flow rate adjustment valve 62. The flow rate adjustment valve 62 is not particularly limited as long as it is a known valve that can be shut off and has a flow rate adjustment capability, such as a needle valve. Also, the opening degree of the flow rate adjustment valve 62 may be adjusted manually or by computer control.

[0089] If the flow rate adjustment unit 60 is a flow rate adjustment valve 62, it may be configured to adjust the opening degree of the flow rate adjustment valve 62 according to the cooling level of the object to be cooled, which is the heat source 81. For example, the opening degree of the flow rate adjustment valve 62 can be made larger when the need for cooling the object to be cooled is lower than when it is in normal operation than when it is in normal operation. This makes it possible, for example, to make the refrigerant flow rate into the evaporator 80 less than the refrigerant flow rate into the bypass flow path 75. Also, since it is not necessary to adjust the amount of refrigerant flowing into the evaporator 80 by the pump 10, the load on the pump 10 can be reduced. Furthermore, if it is desired that the refrigerant flow rate into the evaporator 80 be less than or equal to the minimum flow rate of the pump 10, the opening degree of the flow rate adjustment valve 62 can be increased to reduce the refrigerant flow rate into the evaporator 80.

[0090] Furthermore, although the first embodiment described above shows an example in which an inlet-side on / off valve 51 and an outlet-side on / off valve 52 are provided, the present invention is not limited thereto. For example, both the inlet-side on / off valve 51 and the outlet-side on / off valve 52 are not provided, or either the inlet-side on / off valve 51 or the outlet-side on / off valve 52 is not provided.

[0091] Furthermore, in the first embodiment described above, the bypass channel 75 is shown as being connected downstream of the outlet connection 42 and upstream of the condenser 20, but the present invention is not limited to this. For example, the bypass channel 75 may be directly connected to the condenser 20 and may not be connected to the channel between the outlet connection 42 and the condenser 20.

[0092] Furthermore, although the first embodiment described above shows an example that includes a storage section 30, the present invention is not limited thereto. For example, the storage section 30 may not be provided.

[0093] Furthermore, although the first embodiment described above shows a portable circulation device 100 for a two-phase cooling system, the present invention is not limited to this. For example, the circulation device 100 for a two-phase cooling system may be a fixed installation type.

[0094] Furthermore, in the first embodiment described above, an example was shown in which the refrigerant 2, a gas-liquid mixture, that flows out of the evaporator 80 flows into the condenser 20 while the evaporator 80 is connected, but the present invention is not limited to this. For example, the refrigerant that flows out of the evaporator 80 may be configured to be in a single-phase gaseous state.

[0095] Furthermore, in the second embodiment described above, the detection unit 31 is a liquid level sensor, and an example was shown in which the amount of refrigerant stored in the storage unit 30 as the amount of refrigerant recovered is detected by measuring the liquid level 3 of the liquid phase refrigerant 1 stored in the storage unit 30. However, the present invention is not limited to this. For example, the detection unit may be a differential pressure level sensor, and the amount of refrigerant stored in the storage unit as the amount of refrigerant recovered may be detected by measuring the height of the liquid level based on the difference between the pressure at the bottom of the storage unit and the pressure at the liquid level. Alternatively, the detection unit may be any other known sensor.

[0096] Furthermore, although the second embodiment described above shows an example in which the set liquid level 5 is set by the control unit 91, the present invention is not limited to this. For example, the set liquid level 5 may be set by the user.

[0097] Furthermore, in the second embodiment described above, the detection unit 31 was shown to detect the amount of refrigerant stored in the storage unit 30 as the amount of refrigerant recovered, but the present invention is not limited thereto. For example, the circulation device for a two-phase cooling system may be configured to have detection units provided near the inlet and outlet of the storage unit, and to detect the amount of refrigerant recovered based on the refrigerant flow rate detected by the detection unit near the inlet and the refrigerant flow rate detected by the detection unit near the outlet. In this case, when the difference between the refrigerant flow rate detected by the detection unit near the inlet and the refrigerant flow rate detected by the detection unit near the outlet falls below a threshold, the control unit may stop the operation of the pump and terminate the refrigerant recovery process. Alternatively, for example, the circulation device for a two-phase cooling system may be configured to have a detection unit provided between the outlet-side on / off valve and the confluence unit, and to detect the amount of refrigerant recovered based on the refrigerant flow rate detected by the detection unit.

[0098] Furthermore, in the second embodiment described above, the control unit 91 is shown to stop the operation of the pump 10 and terminate the refrigerant recovery process when the amount of refrigerant stored detected by the detection unit 31 becomes equal to or equal to a preset set storage amount, but the present invention is not limited to this. For example, as in the third modified example, the control unit 91 may stop the operation of the pump 10 and terminate the refrigerant recovery process when the amount of change in the amount of refrigerant stored detected by the detection unit 31 becomes equal to or equal to a preset set change amount. Note that the amount of change in the amount of refrigerant stored includes the amount of change in the liquid level of the refrigerant 6 (see Figure 9).

[0099] As shown in Figure 9, immediately after the inlet valve 51 is closed in the refrigerant recovery state, the rate of change 6 per unit time of the liquid level of the liquid phase refrigerant 1 stored in the storage unit 30 is largest, and as time t progresses, the rate of change 6 per unit time of the liquid level of the liquid phase refrigerant 1 decreases. Therefore, the rate of change 7 per unit time of the liquid level of the liquid phase refrigerant 1 is set in advance. The rate of change 7 is a reference value that can be considered to indicate that the refrigerant remaining in the evaporator 80 has been recovered into the storage unit 30. The rate of change 7 is set in advance by the user. The rate of change 7 is stored in the memory unit 92.

[0100] In the refrigerant recovery state, the control unit 91 acquires the liquid level of the liquid-phase refrigerant 1 stored in the storage unit 30, as detected by the detection unit 31. Based on the liquid level of the liquid-phase refrigerant 1 detected by the detection unit 31, the control unit 91 acquires the amount of change 6 per unit time of the liquid level of the liquid-phase refrigerant 1. Then, when the amount of change 6 of the liquid level of the liquid-phase refrigerant 1 becomes less than or equal to a preset set change amount 7 (time t2), the control unit 91 controls the outlet-side on / off valve 52 to close it and prevent the refrigerant from flowing out from the outlet-side on / off valve 52 to the outlet-side connection unit 42, and also controls the pump 10 to stop operation and end the refrigerant recovery process.

[0101] According to the third modification, as described above, in the refrigerant recovery state, when the change in the amount of stored refrigerant detected by the detection unit 31 when the refrigerant is circulated via the bypass flow path 75 without passing through the evaporator 80 falls below a preset change amount of 7, the control unit 91 controls the pump 10 to stop operation and terminate the refrigerant recovery process. This allows the control unit 91 to reliably detect, for example, that the refrigerant remaining in the evaporator 80 has been recovered into the storage unit 30, even if the total amount of refrigerant changes due to a decrease in refrigerant during normal operation to cool the heat source 81, based on the preset change amount of 7.

[0102] Furthermore, the control unit 91 may be configured to stop the operation of the pump 10 and terminate the refrigerant recovery process when the liquid level 3 of the liquid phase refrigerant 1 detected by the detection unit 31 becomes equal to or greater than a preset set liquid level 5 (see Figure 7), and the amount of change 6 of the liquid phase refrigerant 1 detected by the detection unit 31 becomes equal to or less than a preset set change 7.

[0103] Furthermore, in the second embodiment described above, the control unit 91 is configured to perform the following actions: control to close the inlet valve 51 using the inlet valve opening / closing mechanism 53; control to close the outlet valve 52 using the outlet valve opening / closing mechanism 54 based on the set storage amount; and control to stop the operation of the pump 10 based on the set storage amount. However, the present invention is not limited to this. For example, the user may perform any or all of the following operations: closing the inlet valve 51; closing the outlet valve 52 based on the set storage amount; and stopping the operation of the pump 10 based on the set storage amount. If the user performs all of the following operations: closing the inlet valve 51; closing the outlet valve 52 based on the set storage amount; and stopping the operation of the pump 10 based on the set storage amount, the control unit may not be provided.

[0104] For example, before recovering the refrigerant from the evaporator 80, the user may manually close the inlet valve 51. The user may also manually close the outlet valve 52 based on a visual check of the liquid level gauge. The user may also stop the operation of the pump 10 based on a visual check of the liquid level gauge.

[0105] Furthermore, in the second embodiment and the third modified example described above, the control unit 91 is configured to close the outlet-side on / off valve 52 with the outlet-side on / off valve opening / closing mechanism 54 and stop the operation of the pump 10, thereby ending the refrigerant recovery process, when the amount of refrigerant stored detected by the detection unit 31 exceeds a preset storage amount, or when the amount of change in the amount of refrigerant stored detected by the detection unit 31 falls below a set change amount. However, the present invention is not limited thereto. For example, as in the fourth modified example, the circulation device 300 for the two-phase cooling system may further include a notification unit 93, and the control unit 91 may be configured to notify the notification unit 93 that the amount of refrigerant stored detected by the detection unit 31 has exceeded a preset storage amount, or that the amount of change in the amount of refrigerant stored detected by the detection unit 31 has fallen below a set change amount. As a result, the user can recognize when the amount of refrigerant stored detected by the detection unit 31 exceeds the set storage amount, or when the change in the amount of refrigerant stored detected by the detection unit 31 falls below the set change amount. Therefore, the user can quickly perform the operation of closing the outlet valve 52 and stopping the operation of the pump 10.

[0106] When the notification unit 93 notifies the user of the above, the user performs an operation to close the outlet-side on / off valve 52 and to stop the operation of the pump 10.

[0107] In this case, the notification unit 93 includes a display unit 94, and the control unit 91 may control the display unit 94 to display a notification stating "Refrigerant has been recovered" when the amount of refrigerant stored detected by the detection unit 31 exceeds a preset storage amount, or when the amount of change in the amount of refrigerant stored detected by the detection unit 31 falls below a set change amount. Alternatively, the notification unit 93 may include an audio output unit 95 instead of the display unit 94, or together with the display unit 94, and the control unit 91 may control the audio output unit 95 to announce "Refrigerant has been recovered" when the amount of refrigerant stored detected by the detection unit 31 exceeds a preset storage amount, or when the amount of change in the amount of refrigerant stored detected by the detection unit 31 falls below a set change amount.

[0108] Furthermore, while the first and second embodiments described above show examples comprising an inlet-side on / off valve 51, an outlet-side on / off valve 52, and a flow rate adjustment unit 60, the present invention is not limited thereto. For example, as shown in the fifth modified example in Figure 12, instead of the inlet-side on / off valve 51, the outlet-side on / off valve 52, and the flow rate adjustment unit 60, a first three-way valve 98 may be provided at the branching section 76 and a second three-way valve 99 may be provided at the merging section 77. In this case, the control unit 91 may be configured to control the switching between the first three-way valve 98 and the second three-way valve 99, or the user may switch between the first three-way valve 98 and the second three-way valve 99.

[0109] [Aspect] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0110] (Item 1) A circulation device for a two-phase cooling system that constitutes a two-phase cooling system by connecting a detachable evaporator, A pump for supplying the refrigerant, An inlet connection portion connected to the inlet of the refrigerant in the evaporator and an outlet connection portion connected to the outlet of the refrigerant are provided downstream of the pump, A condenser is provided downstream of the outlet connection portion for cooling the refrigerant, The system includes a bypass channel that branches downstream of the pump and upstream of the inlet connection, allowing the refrigerant to flow to the condenser without passing through the inlet connection and the outlet connection, A circulation device for a two-phase cooling system that circulates the refrigerant via the bypass flow path, without going through the inlet and outlet connections, when at least the evaporator is not connected to the inlet and outlet connections.

[0111] (Item 2) A circulation device for a two-phase cooling system according to item 1, wherein, in a normal operating state in which the evaporator is connected to the inlet-side connection and the outlet-side connection, a portion of the refrigerant is circulated through the evaporator and the remaining portion of the refrigerant is circulated through the bypass flow path.

[0112] (Item 3) A circulation device for a two-phase cooling system according to item 1 or 2, further comprising a flow rate adjustment unit provided in the bypass channel.

[0113] (Item 4) The circulation device for a two-phase cooling system according to item 3, wherein the flow rate adjustment unit is an orifice that adjusts the flow rate of the refrigerant flowing through the bypass channel.

[0114] (Item 5) The circulation device for a two-phase cooling system according to item 3, wherein the flow rate adjustment unit is a flow rate adjustment valve that adjusts the flow rate of the refrigerant flowing through the bypass channel.

[0115] (Item 6) The condenser is configured to cool the gaseous phase of the gaseous-liquid mixture of the refrigerant by condensing it with a coolant flowing in from the outside, or to cool the liquid phase of the refrigerant, as described in any one of items 1 to 5.

[0116] (Item 7) The bypass channel branches downstream of the pump and upstream of the inlet connection, and is connected downstream of the outlet connection and upstream of the condenser, in the circulation device for a two-phase cooling system according to any one of items 1 to 6.

[0117] (Item 8) The circulation device for a two-phase cooling system according to item 7, further comprising: an inlet-side on / off valve provided between the branching portion where the bypass flow path branches downstream of the pump and the inlet-side connection portion for opening and closing the flow path of the refrigerant; and an outlet-side on / off valve provided between the outlet-side connection portion and the connection portion where the bypass flow path is connected downstream of the outlet-side connection portion for opening and closing the flow path of the refrigerant.

[0118] (Item 9) A circulation device for a two-phase cooling system according to any one of items 1 to 8, further comprising a storage section downstream of the condenser and upstream of the pump.

[0119] (Item 10) A circulation device for a two-phase cooling system according to any one of items 1 to 9, wherein, when the evaporator is connected to the inlet connection and the outlet connection, the gas-liquid mixture of refrigerant discharged from the evaporator flows into the condenser.

[0120] (Item 11) Further comprising an inlet-side on / off valve for opening and closing the refrigerant flow path, located between the branching portion where the bypass flow path branches and the inlet-side connection portion downstream of the pump, A circulation device for a two-phase cooling system according to item 1, wherein, when recovering the refrigerant from the evaporator, the evaporator is connected to the inlet-side connection and the outlet-side connection, and in a refrigerant recovery state in which the inlet-side on / off valve is closed, the refrigerant is circulated through the bypass flow path without going through the evaporator, and the refrigerant from the evaporator is guided to the condenser.

[0121] (Item 12) A detection unit for detecting the amount of refrigerant recovered, The circulation device for a two-phase cooling system according to item 11, further comprising a control unit that stops the operation of the pump and terminates the refrigerant recovery process based on the detection result from the detection unit.

[0122] (Item 13) The system further comprises a storage section located downstream of the condenser and upstream of the pump, The detection unit detects the amount of refrigerant stored in the storage unit as the amount of refrigerant recovered, in the circulation device for a two-phase cooling system as described in item 12.

[0123] (Item 14) In the refrigerant recovery state, when the amount of refrigerant stored detected by the detection unit while the refrigerant is circulated through the bypass channel without passing through the evaporator becomes equal to or greater than a preset storage amount, the control unit controls the pump to stop operation and terminate the refrigerant recovery process, as described in item 13.

[0124] (Item 15) In the refrigerant recovery state, when the amount of change in the amount of stored refrigerant detected by the detection unit while the refrigerant is circulated through the bypass channel without going through the evaporator falls below a preset change amount, the control unit performs control to stop the operation of the pump and terminate the refrigerant recovery process, as described in item 13.

[0125] (Item 16) A circulation device for a two-phase cooling system according to item 14 or 15, further comprising a notification unit that notifies when the amount of refrigerant stored detected by the detection unit has become equal to or greater than the set storage amount, or when the amount of change in the amount of refrigerant stored detected by the detection unit has become equal to or less than the set change amount.

[0126] (Item 17) The outlet side connection portion and the connection portion downstream of the outlet side connection portion to which the bypass flow path is connected are provided, and the outlet side on-off valve for opening and closing the flow path of the refrigerant is further provided, The circulation device for a two-phase cooling system according to item 13, wherein the control unit performs control to close the outlet-side on / off valve based on the detection result from the detection unit to prevent the outflow of the refrigerant from the outlet-side on / off valve to the outlet-side connection part.

[0127] (Item 18) A refrigerant circulation method in a circulation device for a two-phase cooling system, which constitutes a two-phase cooling system that circulates a refrigerant by connecting a detachable evaporator, The steps include: circulating the refrigerant through a bypass passage that allows the refrigerant to flow without passing through the inlet and outlet connections, when at least the evaporator is not connected to the inlet connection and outlet connection in the evaporator; A refrigerant circulation method comprising the step of cooling the refrigerant that has flowed through the bypass channel and into the condenser.

[0128] (Item 19) When recovering the refrigerant from the evaporator, the evaporator is connected to the inlet connection and the outlet connection, and in a refrigerant recovery state in which the inlet-side on / off valve provided between the branching portion where the bypass flow path branches and the inlet connection is closed, the refrigerant is circulated through the bypass flow path without going through the evaporator, and the refrigerant from the evaporator is guided to the condenser, The refrigerant circulation method according to item 18, further comprising the step of stopping the circulation of the refrigerant and terminating the refrigerant recovery process based on the detection result of the amount of refrigerant recovered. [Explanation of symbols]

[0129] 2. Refrigerant mixture (gas-liquid mixture) 5. Set liquid level (set storage volume) 7. Amount of change in settings 10 pumps 20 Condenser 23 Coolant 30 Storage section 31 Detection unit 41 Inlet side connection 42 Outlet side connection 51 Inlet side on / off valve 52 Outlet side on / off valve 60 Flow rate adjustment section 61 Orifice 62 Flow control valve 75 Bypass channel 80 Evaporator 91 Control Unit 93 Hochi Department 100, 300 Circulation device for two-phase cooling systems 200, 400 Two-Phase Cooling System

Claims

1. A circulation device for a two-phase cooling system that constitutes a two-phase cooling system by connecting a detachable evaporator, A pump for supplying the refrigerant, An inlet connection portion connected to the inlet of the refrigerant in the evaporator and an outlet connection portion connected to the outlet of the refrigerant are provided downstream of the pump, A condenser is provided downstream of the outlet connection portion for cooling the refrigerant, The system includes a bypass channel that branches downstream of the pump and upstream of the inlet connection, allowing the refrigerant to flow to the condenser without passing through the inlet connection and the outlet connection, A circulation device for a two-phase cooling system that circulates the refrigerant via the bypass flow path, without going through the inlet and outlet connections, when at least the evaporator is not connected to the inlet and outlet connections.

2. The circulation device for a two-phase cooling system according to claim 1, wherein in a normal operating state in which the evaporator is connected to the inlet-side connection and the outlet-side connection, a portion of the refrigerant is circulated through the evaporator and the remaining portion of the refrigerant is circulated through the bypass flow path.

3. The circulation device for a two-phase cooling system according to claim 1 or 2, further comprising a flow rate adjustment unit provided in the bypass flow path.

4. The circulating device for a two-phase cooling system according to claim 1, wherein the condenser is configured to cool the gas phase of the gas-liquid mixed refrigerant by condensing it with a coolant flowing in from the outside, or to cool the liquid phase of the refrigerant.

5. The circulation device for a two-phase cooling system according to claim 1, wherein the bypass channel branches downstream of the pump and upstream of the inlet connection and is connected downstream of the outlet connection and upstream of the condenser.

6. The circulation device for a two-phase cooling system according to claim 5, further comprising: an inlet-side on / off valve provided between the branching portion where the bypass flow path branches downstream of the pump and the inlet-side connection portion for opening and closing the flow path of the refrigerant; and an outlet-side on / off valve provided between the outlet-side connection portion and the connection portion where the bypass flow path is connected downstream of the outlet-side connection portion for opening and closing the flow path of the refrigerant.

7. The circulation device for a two-phase cooling system according to claim 1, wherein, when the evaporator is connected to the inlet-side connection and the outlet-side connection, the gas-liquid mixture of refrigerant discharged from the evaporator flows into the condenser.

8. Further comprising an inlet-side on / off valve for opening and closing the refrigerant flow path, located between the branching portion where the bypass flow path branches and the inlet-side connection portion downstream of the pump, The circulation device for a two-phase cooling system according to claim 1, wherein, when recovering the refrigerant from the evaporator, the evaporator is connected to the inlet side connection and the outlet side connection, and in a refrigerant recovery state in which the inlet side on / off valve is closed, the refrigerant is circulated through the bypass flow path without going through the evaporator, and the refrigerant from the evaporator is guided to the condenser.

9. A detection unit for detecting the amount of refrigerant recovered, The circulation device for a two-phase cooling system according to claim 8, further comprising a control unit that stops the operation of the pump and terminates the refrigerant recovery process based on the detection result from the detection unit.

10. Further comprising a storage section provided downstream of the condenser and upstream of the pump, The detection unit detects the amount of refrigerant stored in the storage unit as the amount of refrigerant recovered, In the refrigerant recovery state, when the amount of refrigerant stored detected by the detection unit while the refrigerant is circulated through the bypass channel without passing through the evaporator becomes equal to or greater than a preset storage amount, the control unit controls the pump to stop operation and terminate the refrigerant recovery process, as described in claim 9.

11. The system further comprises a storage section provided downstream of the condenser and upstream of the pump, The detection unit detects the amount of refrigerant stored in the storage unit as the amount of refrigerant recovered, In the refrigerant recovery state, when the amount of change in the amount of stored refrigerant detected by the detection unit while the refrigerant is circulated through the bypass channel without going through the evaporator falls below a preset set change amount, the control unit performs control to stop the operation of the pump and terminate the refrigerant recovery process, as described in claim 9.

12. The circulation device for a two-phase cooling system according to claim 10, further comprising a notification unit that notifies that the amount of refrigerant stored detected by the detection unit has exceeded the set storage amount.

13. The system further comprises a storage section provided downstream of the condenser and upstream of the pump, The detection unit detects the amount of refrigerant stored in the storage unit as the amount of refrigerant recovered, The outlet side connection portion and the connection portion downstream of the outlet side connection portion to which the bypass flow path is connected are provided, and the outlet side on-off valve for opening and closing the flow path of the refrigerant is further provided, The circulation device for a two-phase cooling system according to claim 9, wherein the control unit performs control to close the outlet-side on / off valve based on the detection result from the detection unit to prevent the refrigerant from flowing out from the outlet-side on / off valve to the outlet-side connection part.

14. A refrigerant circulation method in a circulation device for a two-phase cooling system, which constitutes a two-phase cooling system that circulates a refrigerant by connecting a detachable evaporator, The steps include: circulating the refrigerant through a bypass passage that allows the refrigerant to flow without passing through the inlet and outlet connections, when at least the evaporator is not connected to the inlet connection and outlet connection in the evaporator; A refrigerant circulation method comprising the step of cooling the refrigerant that has flowed through the bypass channel and into the condenser.

15. When recovering the refrigerant from the evaporator, the evaporator is connected to the inlet connection and the outlet connection, and in a refrigerant recovery state in which the inlet-side on / off valve provided between the branching portion where the bypass flow path branches and the inlet connection is closed, the refrigerant is circulated through the bypass flow path without going through the evaporator, and the refrigerant from the evaporator is guided to the condenser, The refrigerant circulation method according to claim 14, further comprising the step of stopping the circulation of the refrigerant and terminating the refrigerant recovery process based on the detection result of the amount of refrigerant recovered.

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