Liquid immersion cooling device

Abstract

To provide a liquid immersion cooling system that offers enhanced environmental resistance and high cooling efficiency. [Solution] A liquid immersion cooling device (10) for a circuit board (141) having at least a heat-generating electronic circuit section comprises a pressure vessel (100) filled with liquid refrigerant, a pump (203) for forcibly flowing the refrigerant, a temperature-adjustable accumulator (204) for temporarily storing the refrigerant, and a sensor (113) for detecting the pressure and temperature inside the pressure vessel. The device adjusts the pressure and temperature of the refrigerant inside the pressure vessel to a state suitable for the phase change between vaporization and condensation by adjusting the pump's operation and the accumulator's temperature according to the sensor's detection data.

Description

Technical Field

[0006]

[0001] The present invention relates to a technique for cooling electronic devices that generate heat.

Background Art

[0002] Today's electronic devices are equipped with many semiconductor circuits. In particular, integrated circuits such as CPUs (central processing units) or processors that perform various controls of electronic devices are essential electronic components. Usually, consumer electronic components are not designed for use in harsh environments. Therefore, when use in an environment where temperature, pressure, vibration, etc. are outside the normal range is assumed, environmental resistance enhancement (ruggedization) technology is essential.

[0003] As an example of ruggedization technology, Patent Document 1 discloses a space environmental resistance enhancement container for protecting consumer electronic components from cosmic rays. This space environmental resistance enhancement container is formed of aluminum with a thickness of 3 mm, aiming at weight reduction and reliable shielding of cosmic rays (mainly electrons and protons).

[0004] On the other hand, many electronic components include semiconductor circuits (such as processors, etc.) that generate heat during operation. When such heat-generating electronic components are sealed in a container, it is necessary to provide means for discharging heat to the outside. For example, electronic devices mounted on artificial satellites are equipped with circuit boards that include integrated circuits that perform high-speed calculations and generate a large amount of heat. Therefore, not only ruggedization technology but also cooling technology is essential.

[0005] Patent Document 1 mentioned above discloses a configuration in which a cooling plate is provided on the bottom plate of the container to conduct the heat generated by the electronic components to the outside for heat dissipation. Also, Patent Document 2 discloses a heat dissipation device in which the heat pipes provided at the heat generation part of the device mounted on the artificial satellite and the heat pipes at the heat dissipation part are joined outside the heat generation part to improve the heat dissipation efficiency.

[0006] In recent years, immersion cooling, a method of cooling electronic devices such as computers by immersing the electronic device itself in a refrigerant tank, has attracted attention. For example, Patent Document 3 discloses an immersion cooling device in which an electronic device is immersed in a refrigerant tank filled with a first refrigerant, a second refrigerant is flowed from the outside through a liquid cooling jacket for further cooling the electronic device, and the first refrigerant in the refrigerant tank is made to flow by a liquid flow generator in the refrigerant tank, thereby increasing the cooling efficiency in the refrigerant tank. Patent Document 4 also discloses an immersion cooling device in which the refrigerant is moved by a pump, and describes an example in which heat from electronic components is efficiently dissipated by the convection and boiling of the refrigerant. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-166899 [Patent Document 2] Japanese Patent Application Publication No. 7-025395 [Patent Document 3] Patent No. 6720752 [Patent Document 4] U.S. Patent No. 9750159B2 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, in the heat dissipation methods disclosed in Patent Documents 1 and 2, it is difficult to obtain high heat dissipation efficiency because the heat from the integrated circuit is discharged through heat conduction between multiple components.

[0009] Furthermore, the immersion cooling devices described in Patent Documents 3 and 4 require means for circulating a first refrigerant to immerse the electronic equipment and means for circulating a second refrigerant to cool the first refrigerant, which complicates their structure and manufacturing process.

[0010] Furthermore, the immersion cooling systems described in Patent Documents 3 and 4 are cooling methods intended for normal use on Earth. For this reason, they are not designed for use in environments with large vibrations, such as those experienced during rocket launches or in a weightless environment. Consequently, if they are installed in a spacecraft as is, convection of the coolant does not occur in the weightless environment of space, causing the boiling bubbles to not detach from the heat dissipation fins and resulting in a dry-out phenomenon.

[0011] Therefore, the objective of the present invention is to enhance environmental resistance and obtain high cooling efficiency. can The objective is to provide a liquid immersion cooling device. [Means for solving the problem]

[0012] According to one aspect of the present invention, A liquid immersion cooling device for a circuit board having at least a heat-generating electronic circuit section, comprising: a pressure vessel filled with a liquid refrigerant; a pump for forcibly circulating the refrigerant; a temperature-adjustable accumulator for temporarily storing the refrigerant; and a sensor for detecting the pressure and temperature inside the pressure vessel, wherein the device adjusts the pump's operation and the accumulator's temperature according to the sensor's detection data to adjust the pressure and temperature of the refrigerant inside the pressure vessel to a state suitable for the phase change between vaporization and condensation. . [Effects of the Invention]

[0013] According to the present invention, a circuit board is placed in a pressure vessel immersed in a refrigerant, By adjusting the pressure and temperature of the refrigerant inside the pressure vessel to a state suitable for the phase change between vaporization and condensation, This enhances environmental resistance and provides high cooling efficiency. can . [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic side cross-sectional view of a liquid immersion cooling device according to a first embodiment of the present invention. [Figure 2] Figure 2 is an exploded side cross-sectional view illustrating the configuration of the pressure vessel of the immersion cooling device according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view taken along line II in Figure 2. [Figure 4] Figure 4 is a cross-sectional view taken along line II-II in Figure 2. [Figure 5] Figure 5 is an exploded perspective view schematically showing an example of a pressure vessel of an immersion cooling device according to the first embodiment. [Figure 6] Figure 6 is a schematic cross-sectional view of a pressure vessel showing an example of slot card installation inside the pressure vessel of a liquid immersion cooling device according to the first embodiment. [Figure 7]FIG. 7 is a schematic block diagram showing the connection between the circuit board inside the pressure vessel of the liquid immersion cooling device according to the first embodiment and the external electrical system. [Figure 8] FIG. 8 is a schematic block diagram for explaining the overall configuration and operation of the liquid immersion cooling device according to the first embodiment. [Figure 9] FIG. 9 is a schematic side cross-sectional view of the liquid immersion cooling device according to the second embodiment of the present invention. [Figure 10] FIG. 10 is an exploded side cross-sectional view for explaining the configuration of the pressure vessel of the liquid immersion cooling device according to the second embodiment. [Figure 11] FIG. 11 is a schematic configuration diagram of a refrigerant filling device for filling a refrigerant into a pressure vessel.

Mode for Carrying Out the Invention

[0015] <Summary of the Embodiment> According to an embodiment of the present invention, a pressure vessel composed of at least one detachable lid and a container body is filled with a refrigerant, and a circuit board is arranged in a state of being immersed in the refrigerant inside the pressure vessel. A refrigerant inlet and a refrigerant outlet for forcibly circulating the refrigerant are provided in one lid, and both ends of the circuit board are fixed by mounting members provided on the container body.

[0016] The refrigerant flows into the pressure vessel from the refrigerant inlet by a forced liquid flow generator provided outside the pressure vessel. The refrigerant flowing in from the refrigerant inlet flows over the front and back surfaces of the circuit board and flows out from the refrigerant outlet. The refrigerant inlet and the refrigerant outlet are provided in one lid, and the refrigerant flowing in from the refrigerant inlet flows on one surface side of the circuit board, and flows along the inner surface of the container to the other surface side of the circuit board and flows out from the refrigerant outlet. As a result, the periphery of the circuit board is filled with the flowing refrigerant, enabling efficient cooling. In addition, the circuit board is surrounded by the pressure vessel and the refrigerant, and both ends of the circuit board are fixed by mounting members inside the pressure vessel, so the environmental resistance is enhanced. In particular, it has excellent resistance to harsh environments such as extremely cold / extremely hot regions and outer space, and environments that receive large vibrations such as during rocket launches.

[0017] During assembly, the lid and the container body can be separated to allow for the installation of the electronic circuit board, and the electronic circuit board can be easily placed inside the pressure vessel simply by joining the lid and the container body. Preferably, the container body has a three-part configuration with lids on opposite openings, with the refrigerant inlet and outlet on one lid and the electrical terminals on the other lid. This allows for the separation of the mechanical design of the container, the design of the electrical system including the electronic circuit board and electrical terminals, and the design of the refrigerant thermal control system, thereby improving design efficiency.

[0018] Furthermore, according to this embodiment, by providing a refrigerant inlet and outlet on one lid, a thermal control system consisting of a forced liquid flow generator such as a pump and a heat dissipation mechanism can be configured on the side of the lid. This allows for the creation of a circulation system in which the refrigerant flowing out from the refrigerant outlet of the pressure vessel is cooled by the thermal control system and returned to the pressure vessel. Because the refrigerant on the electronic circuit board is forcibly flowed by the forced liquid flow generator, the dry-out phenomenon can be prevented even in a space where gravity can be ignored, allowing for efficient cooling of the electronic circuit board and the release of heat to the outside.

[0019] Embodiments of the present invention will be described in detail below with reference to the drawings. However, the components, their shapes, dimensions, dimensional ratios, and arrangements described in the following embodiments are illustrative examples for illustrating these embodiments and are not intended to limit the technical scope of the present invention to them alone.

[0020] 1. First Embodiment 1.1) Configuration As illustrated in Figures 1 to 4, the immersion cooling device 10 according to the first embodiment of the present invention consists of a pressure vessel 100 and a thermal control system 200. The pressure vessel 100 consists of a cylindrical container body 101 and detachable first lid 110 and second lid 120 provided on opposing opening surfaces of the container body 101, respectively, and a refrigerant 130 is sealed inside the pressure vessel. The first lid 110 and the second lid 120 are airtightly joined to the opening surfaces on both sides of the container body 101 by a plurality of joining members 102 such as bolts. Here, the first lid 110 is used for the refrigerant system and the second lid 120 is used for the electrical system.

[0021] Mounting flanges 103 and 104 are provided at the center of both ends of the container body 101, and a plate 140, described later, is fixed to these mounting flanges 103 and 104 as mounting members. In addition, flanges 105 and 106 that protrude outward are provided at both open ends of the container body 101, and the first lid 110 and the second lid 120 are joined to these flanges, respectively.

[0022] The first lid 110 has a refrigerant outlet 111 through which the refrigerant 130 flows out, and a refrigerant inlet 112 through which the refrigerant 130, whose temperature has been regulated via the thermal control system 200, flows in. Furthermore, a sensor 113 for detecting the pressure and temperature inside the pressure vessel 100 is provided between the refrigerant outlet 111 and the refrigerant inlet 112, closer to the refrigerant outlet 111. The first lid 110 is also provided with a flange 114 that protrudes inward so as to contact the mounting flange 103 of the vessel body 101, located between the pressure / temperature sensor 113 and the refrigerant inlet 112. Therefore, the flange 114 and the mounting flange 103 constitute a partition wall that separates the upper and lower parts of the pressure vessel 100 on the first lid 110 side (upper and lower parts of the paper in Figure 1) (see Figures 1 and 3). This prevents the refrigerant 130 flowing in from the refrigerant inlet 112 from flowing directly to the pressure / temperature sensor 113 and the refrigerant outlet 111. Furthermore, the opening of the first lid 110 is provided with a flange 115 that protrudes outward, and is joined to the flange 105 of the container body 101 by a joining member 102 (see Figure 2).

[0023] The second lid 120 has a hermetic terminal 121 in its approximate center, which is an electrical terminal for transmitting and receiving signals to and from the outside and for supplying power. The hermetic terminal 121 is connected to a connector 123 through a cable 122 inside the refrigerant 130, and the connector 123 is connected to a connector 142 provided on the circuit board 141. In addition, a flange 124 that protrudes outward is provided at the opening of the second lid 120 and is joined to the flange 106 of the container body 101 by a joining member 102 (see Figure 2).

[0024] A plate 140 is fixed inside the pressure vessel 100, supported at both ends by mounting flanges 103 and 104, which serve as mounting members. A circuit board 141 is fixed to the surface of the plate 140 on the refrigerant outlet 111 side, and a heat dissipation fin 143 is fixed to the surface on the refrigerant inlet 112 side. A connector 142 is provided at the end of the circuit board 141 on the second lid 120 side, and as described above, it is connected to a hermetic terminal 121 through a connector 123 and cable 122, enabling signal transmission and reception and power supply between the circuit board 141 and the outside.

[0025] The thermal control system 200 consists of piping 201 connected to the refrigerant outlet 111 and the refrigerant inlet 112, a valve 202 located near the refrigerant outlet 111, a pump 203 which is a forced liquid flow generator located near the refrigerant inlet 112, an accumulator 204 having a heating means, and a heat sink 205 radiatively coupled to the piping 201. When the pump 203 is driven, the refrigerant 130 in the pressure vessel 100 flows from the refrigerant outlet 111 through the valve 202 and the piping 201, and the heat of the refrigerant flowing through the piping 201 is discharged to the outside by the heat sink 205 (see Figure 1).

[0026] The refrigerant, thus dissipated heat, flows into the pressure vessel 100 from the refrigerant inlet 112 through the pump 203 and cools by flowing over the heat dissipation fins 143 and circuit board 141. At this time, even if the refrigerant 130 vaporizes and bubbles BB are formed due to the heat generated by the heat dissipation fins 143 and circuit board 141, the refrigerant 130 is forcibly flowed by the pump 203, so the bubbles BB flow with the refrigerant 130 and condense back into a liquid near the inner wall of the pressure vessel 100. In this way, the refrigerant 130 circulates through the piping 201 of the thermal control system 200 between the inside of the pressure vessel 100 and the refrigerant outlet 111 and refrigerant inlet 112. The accumulator 204 is a container that temporarily stores gas / liquid and has a heater inside. Therefore, by controlling the heater of the accumulator 204, the pressure and temperature of the refrigerant 130 can be adjusted to a state suitable for phase change (vaporization and condensation).

[0027] As illustrated in Figure 2, the plate 140 is fixed to the mounting flanges 103 and 104 of the container body 101 by tap bolts 107 and 108. As shown in Figure 4, the mounting flanges 103 and 104 are provided with clearance holes for the tap bolts 107 and 108 to pass through. This makes it possible to visually check the bolt tightening process when attaching the plate 140 to the mounting flanges 103 and 104, thus facilitating the work.

[0028] As shown in Figure 1, the pressure vessel 100 and thermal control system 200 described above are fixed to the satellite or other mounting panel 300 by legs 301 and 302. The piping 201, pump 203, accumulator 204, and heat sink 205 of the thermal control system 200 are also fixed to the mounting panel 300 by support members (not shown) to prevent them from coming loose due to vibration or other reasons.

[0029] Figure 5 illustrates a more detailed shape of the pressure vessel 100 described above. In Figure 5, the same reference numerals are used for the same components as in Figures 1 to 4.

[0030] Furthermore, as illustrated in Figure 6, a slot card 144 can be mounted on the circuit board 141 with a spacer 145 in between, and connected to the circuit board 141 by a dedicated immersion cable 146 and connector 147. By mounting the slot card 144 parallel to the circuit board 141 in this way, the performance of the processor and other components can be expanded without increasing the diameter of the container body 101, and the cooling efficiency can be maintained because the flow of the refrigerant 130 is not obstructed.

[0031] Furthermore, by using the immersion-only cable 146, the layout of the circuit board 141 and expansion slot cards inside the pressure vessel 100 can be freely arranged. As a result, expansion slot cards, which are generally mounted perpendicular to the circuit board, can be mounted parallel to the circuit board 141, enabling miniaturization without unnecessarily increasing the diameter of the pressure vessel 100.

[0032] 1.2) Implementation Example As illustrated in Figure 7, the processor and other components on the circuit board 141 are connected via hermetic terminals 121 to the operating device 501 and power supply 502 mounted on the outside of the pressure vessel 100. The operating device 501 can send commands to operate the circuit board 141 via software and retrieve corresponding data. The power supply 502 supplies power for the operation of the circuit board 141.

[0033] The following describes the functional configuration of the immersion cooling device 10 according to this embodiment when mounted on an artificial satellite, which is a spacecraft, with reference to Figure 8. Here, the drive system 600 controls the pump 203 and accumulator 204 of the thermal control system 200 according to the control of the circuit board 141.

[0034] In Figure 8, the control device 501 receives input from the pressure / temperature sensor 113 for the pressure inside the pressure vessel 100 and the temperature of the refrigerant, and transmits an operation command including the pressure and temperature data to the circuit board 141. The processor on the circuit board 141 adjusts the pressure inside the pressure vessel 100 and the temperature of the refrigerant by transmitting data to the drive system 600 via the control device 501, according to the pressure and temperature data. Specifically, by monitoring the detection data from the pressure / temperature sensor 113 and adjusting the drive of the pump 203 and the heater temperature of the accumulator 204, the refrigerant 130 inside the pressure vessel 100 is controlled to a temperature suitable for phase change (vaporization and condensation).

[0035] The refrigerant 130 is a liquid that has electrical insulating and thermal conductive properties, and it is particularly desirable that it contains hydrogen atoms to slow down and shield neutron radiation. As such a refrigerant 130, for example, a liquid such as a fluorocarbon alternative or polyester can be used. In this embodiment, when the temperature of the entire pressure vessel 100 is controlled to 60°C or below, the boiling point of the refrigerant 130 is, for example, about 76°C.

[0036] 1.3) Effects As described above, according to this embodiment, the area around the circuit board 141 inside the pressure vessel 100 is filled with flowing coolant 130, enabling efficient cooling. Furthermore, since the circuit board 141 is surrounded by the pressure vessel 100 and the coolant 130, its resistance to large vibrations and harsh environments such as space is enhanced.

[0037] According to this embodiment, the pressure vessel 100 is divided into three parts: the vessel body 101, a first lid (for the refrigerant system), and a second lid (for the electrical system). By dividing the two lids in this way, into one for the refrigerant system and the other for the electrical system, the design of the mechanical configuration of the vessel, the design of the thermal control system, and the design of the electrical system can be separated, making it easier to derive the optimal solution for the immersion cooling device 10. Specifically, the mechanical design is responsible for the entire pressure vessel 100 and each mechanical joint, the thermal control design is responsible for the installation of the refrigerant circulating piping 201, pump 203, and accumulator 204 on the first lid 110 side, and the electrical design is responsible for the hermetic terminals 121 and circuit board 141 on the second lid 120 side.

[0038] Regarding the support rigidity of the circuit board 141 mounted inside the pressure vessel 100, dedicated mounting flanges 103 and 104 are provided on both sides of the vessel body 101, and both ends of the plate 140 on which the circuit board is mounted are fixed to these flanges. This ensures the support rigidity required to meet vibration resistance requirements, for example, during rocket launch.

[0039] In this embodiment, a first lid 110 for the refrigerant system and a second lid 120 for the electrical system are provided on both sides of the container body 101, but the invention is not limited to this configuration. The first lid 110 and the second lid 120 can be placed adjacent to each other if implementation is feasible.

[0040] 2. Second Embodiment In the first embodiment described above, two lids were used, one for the refrigerant system and the other for the electrical system, but the invention is not limited to this. Even with a liquid immersion cooling system that uses a single lid for both the refrigerant and electrical systems, the same effects as in the first embodiment can be obtained. Specifically, since the area around the electronic circuit board inside the pressure vessel is filled with flowing refrigerant, efficient cooling becomes possible. Furthermore, since the electronic circuit board is surrounded by the pressure vessel and refrigerant, its resistance to large vibrations and harsh environments such as space is enhanced. In addition, the removal and separation of the lids makes the installation of the circuit board easier.

[0041] Hereinafter, a second embodiment of the present invention, a liquid immersion cooling device in which a single lid is used for both the refrigerant system and the electrical system, will be described with reference to Figures 9 and 10. Note that the same reference numerals are used for components similar to those in the first embodiment to simplify the description.

[0042] As illustrated in Figures 9 and 10, the immersion cooling device 40 according to the second embodiment of the present invention consists of a pressure vessel 400 and a thermal control system 200. The pressure vessel 400 consists of a cylindrical container body 401 with an opening on only one side, and a separable lid 410 provided at the opening of the container body 401, with a refrigerant 430 sealed inside. The lid 410 is airtightly joined to the container body 401 by a plurality of joining members 402 such as bolts.

[0043] The opening of the container body 401 is provided with a flange 403 that protrudes outward and is connected to the lid 410. A support member 404 is also provided inside the container body 401, and one end of the plate 440, which will be described later, is supported by fitting it into a slot 405 of the support member 404.

[0044] The lid 410 has a refrigerant outlet 411 through which the refrigerant 430 flows out, and a refrigerant inlet 412 through which the refrigerant 430, whose temperature has been regulated via the thermal control system 200, flows in. Furthermore, a sensor 413 for detecting the pressure and temperature inside the pressure vessel 100 is provided between the refrigerant outlet 411 and the refrigerant inlet 412, closer to the refrigerant outlet 411. Also, near the center of the lid 410, there is a hermetic terminal 421, which is an electrical terminal for transmitting and receiving signals to and from the outside and for supplying power. The hermetic terminal 421 is connected to a connector 423 through a cable 422 inside the refrigerant 430, and the connector 423 is connected to a connector 442 provided on the circuit board 441.

[0045] Furthermore, the lid 410 is provided with an inwardly projecting mounting flange 414 located between the pressure / temperature sensor 413 and the refrigerant inlet 412, and the other end of a plate 440, one end of which is supported by a support member 404, is fixed to the flange 414 and the plate 440. In this way, the flange 414 and the plate 440 form a partition wall separating the upper and lower parts of the pressure vessel 400 on the lid 410 side (upper and lower parts of the paper in Figure 9). This prevents the refrigerant 430 flowing in from the refrigerant inlet 412 from flowing directly to the pressure / temperature sensor 113 and the refrigerant outlet 411. In addition, the joint of the lid 410 is provided with an outwardly projecting flange 415, which is connected to the flange 403 of the vessel body 401 by a connecting member 402 (see Figure 10).

[0046] Inside the pressure vessel 400, the plate 440 is supported and fixed at both ends by mounting flanges 414 and support members 404. A circuit board 441 is fixed to the surface of the plate 440 on the refrigerant outlet 411 side, and heat dissipation fins 443 are fixed to the surface on the refrigerant inlet 412 side. A connector 442 is provided at the end of the circuit board 441 on the lid 410 side, and as described above, it is connected to a hermetic terminal 421 through connector 423 and cable 422, enabling signal transmission and reception and power supply between the circuit board 441 and the outside.

[0047] The thermal control system 200 has piping 201 connected to the refrigerant outlet 411 and refrigerant inlet 412, and has the same structure and function as that of the first embodiment shown in Figure 1, so the same reference numerals are used and the description is omitted.

[0048] As illustrated in Figure 10, one end of the plate 440 is fixed to the mounting flange 414 of the lid 410 by a tap bolt 416. The mounting flange 414 is provided with a clearance hole for the tap bolt 416, which allows for visual inspection when tightening the bolt when attaching the plate 440 to the mounting flange 414, making the work easier. In this way, one end of the plate 440, to which the circuit board 441 and heat sink 443 are attached, is fixed to the mounting flange 414 of the lid 410.

[0049] In the assembly process, first the circuit board 441 and heat sink fins 443 are fixed to the plate 440, and one end of the plate 440 is fixed to the mounting flange 414 of the lid 410. Next, the container body 401 is moved in the direction of the arrow shown in Figure 10 so that the plate 440 with the circuit board 441 and heat sink fins 443 attached is housed inside. This causes the other end of the plate 440 to be inserted into the slot 405 of the support member 404 of the container body 401, thereby fixing both ends of the plate 440. Finally, the container body 401 and the lid 410 are airtightly joined by the fixing member 402, and the refrigerant 430 is introduced into the pressure vessel 400. Guides may be provided at regular intervals on the side of the container body 401 to ensure that the plate 440 fits into the slot 405 of the support member 404.

[0050] As described above, according to this embodiment, the area around the circuit board 441 inside the pressure vessel 400 is filled with flowing coolant 430, enabling efficient cooling. Furthermore, since the circuit board 441 is surrounded by the pressure vessel 400 and the coolant 430, its resistance to large vibrations and harsh environments such as space is enhanced.

[0051] In this embodiment, the pressure vessel 400 is divided into a vessel body 101 and a lid 410. With the lid 410 removed, a plate 440 on which the circuit board 441 is mounted is attached to the mounting flange 414 of the lid 410, and by inserting this into the vessel body 401, the circuit board 441 can be sealed inside the pressure vessel 400.

[0052] The support rigidity of the circuit board 141 mounted inside the pressure vessel 400 is ensured by fixing both ends of the plate 440 with the support member 404 of the vessel body 401 and the mounting flange 414 of the lid 410. This ensures the support rigidity required to meet vibration resistance requirements, for example, during rocket launch.

[0053] 3. Refrigerant charging In the first and second embodiments described above, after assembling the pressure vessels (100, 400), it is necessary to fill the vessels with refrigerant. The procedure for filling the refrigerant will be explained below, using the pressure vessel 100 in the first embodiment as an example. The pressure vessel 400 in the second embodiment employs a similar filling method.

[0054] In Figure 11, the valve 202 at the refrigerant outlet 111 of the pressure vessel 100 is closed, and a valve 801 is provided at the refrigerant inlet 112. Furthermore, selective communication between the pressure vessel 100, the vacuum pump 701, the refrigerant tank 702, and the outside is possible by opening and closing valves 801 to 804 and piping 805.

[0055] First, the mass of the pressure vessel 100 is measured with nothing inside, such as refrigerant. Next, the refrigerant valve 803 and the release valve 804 are closed, and with the vessel valve 801 open, the pressure inside the pressure vessel 100 is monitored while the vacuum pump 701 is used to evacuate it.

[0056] Once the vacuuming is complete, close the vacuum pump valve 802. Next, open the refrigerant valve 803 to fill the pressure vessel 100 with refrigerant from the refrigerant tank 702. Close the refrigerant valve 803 and the vessel valve 801, and open the release valve 804 to discharge the refrigerant in the piping 805. Then, measure the mass of the pressure vessel 100 to confirm the amount of refrigerant filled, and if necessary, open the vessel valve 801 to discharge the refrigerant while measuring the mass. In addition, adjust the internal pressure of the pressure vessel 100 to be within the specified range while checking the pressure sensor with the vacuum pump 701 connected.

[0057] Once the refrigerant is filled and the pressure adjustment is complete, it is connected to the thermal control system 200 as shown in Figure 1, and the pump 203 is driven to circulate the refrigerant as described above, and the circuit board 141 is cooled while the thermal control system 200 controls the temperature.

[0058] Although the present invention has been described in detail based on its embodiments, it goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from its essence. [Industrial applicability]

[0059] This invention is applicable to immersion cooling systems used in harsh environments such as extremely cold / extremely hot regions and outer space. [Explanation of symbols]

[0060] 10 Immersion cooling device 100 Pressure Vessels 101 Container body 103,104 Mounting flange (mounting component) 110 First lid (for refrigerant system) 111 Refrigerant outlet 112 Refrigerant Inlet 120 Second cover (for electrical system) 121 Hermetic terminals (electrical terminals) 130 Refrigerant 140 Plate 141 Circuit board 143 heat dissipation fins 200 Thermal control system 201 Piping 202 Valve 203 Pump 204 Accumulator 205 Heat sink

Claims

1. A liquid immersion cooling device for a circuit board having at least one heat-generating electronic circuit section, A pressure vessel whose interior is filled with a liquid refrigerant, A pump for forcibly circulating the refrigerant, A container for temporarily storing the aforementioned refrigerant, which is a temperature-controlled accumulator, A sensor for detecting the pressure and temperature inside the pressure vessel, A liquid immersion cooling device having a pump drive and an accumulator temperature that adjust the pressure and temperature of the refrigerant in the pressure vessel to a state suitable for the phase change between vaporization and condensation, according to the detection data of the sensor.

2. The pressure vessel consists of a container body and at least one lid detachably attached to the container body. The lid has a refrigerant outlet through which the refrigerant flows out and a refrigerant inlet through which the temperature-controlled refrigerant flows in. The sensor is positioned between the refrigerant outlet and the refrigerant inlet. The liquid immersion cooling device according to feature 1.

3. The immersion cooling device according to claim 2, characterized in that the lid has a protruding wall provided between the sensor and the refrigerant inlet on the inner wall of the lid.

4. The liquid immersion cooling device according to claim 1, characterized in that the pressure vessel is cylindrical in shape.

5. The immersion cooling device according to claim 1, further comprising a drive system that controls the drive of the pump and the accumulator to adjust the pressure and temperature of the refrigerant in the pressure vessel to a state suitable for the phase change between vaporization and condensation, according to the detection data of the sensor.

6. A spacecraft equipped with an immersion cooling device according to any one of claims 1 to 5.

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