Boil-off gas recondensing device

Abstract

Provided is a boil-off gas recondensing device (10) which can be mounted on a boil-off gas discharge line (130) for releasing the internal pressure of an ultra-low temperature liquid storage tank (112). A boil-off gas recondensation device (10) is provided with: a cryostat (12); and a recondenser (14) housed in the cryostat (12) and recondensing the boil-off gas. A cryostat (12) is provided with: a boil-off gas inflow path (18) which is connected to an introduction path (132) of a boil-off gas discharge line (130) and through which boil-off gas can flow from the introduction path (132) to a recondenser (14); and a boil-off gas outflow path (20) which is connected to an external discharge path (134) of the boil-off gas discharge line (130) and through which the boil-off gas can flow out from the after-condenser (14) to the external discharge path (134).

Description

Technical Field

[0001] This invention relates to a condensation device for evaporative gas. Background Technology

[0002] Previously, in so-called immersion cooling, where a superconducting device is cooled by immersion in liquid helium, a recondensation device is known to be installed to recondense the helium gas (also known as the vaporized gas) that vaporizes as a result of cooling. The liquid helium obtained by recondensation can be reused for cooling the superconducting device.

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-92278 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] The aforementioned recondensation device is designed to be integrated with the superconducting device as an auxiliary component, such as being attached as part of the liquid helium tank. Therefore, when considering adding a recondensation device to an existing cryogenic system that did not originally have one, it would require significant modifications to the cryogenic system, such as constructing new interfaces for installing the recondensation device, making it difficult to implement.

[0008] One exemplary objective of one embodiment of the present invention is to provide an evaporative gas recondensation device that is easy to install into a cryogenic system later.

[0009] means for solving technical problems

[0010] According to one embodiment of the present invention, an evaporating gas recondensation device is provided, which can be installed on an evaporating gas discharge pipeline for releasing internal pressure in a cryogenic liquid storage tank. The evaporating gas discharge pipeline includes: an inlet path for introducing evaporating gas from the cryogenic liquid storage tank into the evaporating gas recondensation device; and an external discharge path for discharging the evaporating gas from the evaporating gas recondensation device to the outside. The evaporating gas recondensation device includes: a cryogenic thermostat; and a recondenser housed in the cryogenic thermostat for recondensing the evaporating gas. The cryogenic thermostat includes: an evaporating gas inflow path connected to the inlet path of the evaporating gas discharge pipeline, allowing the evaporating gas to flow from the inlet path into the recondenser; and an evaporating gas outflow path connected to the external discharge path of the evaporating gas discharge pipeline, allowing the evaporating gas to flow from the recondenser out to the external discharge path.

[0011] Invention Effects

[0012] According to the present invention, an evaporative gas recondensation device that is easy to be added to a cryogenic system later can be provided. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the cryogenic system involved in the embodiment.

[0014] Figure 2 This is a schematic diagram showing an example of a cryogenic refrigerator according to an embodiment being installed in a cryogenic thermostat of an evaporative gas recondensation device.

[0015] Figure 3 This is a schematic diagram illustrating another example of the cryogenic system involved in the embodiment.

[0016] Figure 4 This is a schematic diagram illustrating another example of the evaporative gas recondensation apparatus according to the embodiment. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description and drawings, the same or equivalent constituent elements, components, and processes are labeled with the same symbols, and repeated descriptions are omitted where appropriate. For ease of explanation, the proportions or shapes of the illustrated parts are appropriately provided, and should not be interpreted limitingly unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. All features or combinations thereof described in the embodiments are not necessarily essential to the invention.

[0018] Figure 1 This diagram schematically illustrates the cryogenic system 100 according to the embodiment. The cryogenic system 100 includes a cryogenic cooling device 110 for cooling an object 102 to a cryogenic temperature. The cryogenic cooling device 110 includes a cryogenic liquid reservoir 112 for holding a cryogenic refrigerant, i.e., a cryogenic liquid 104, used for cooling the object 102, and is capable of providing immersion cooling. That is, the object 102 is disposed in the cryogenic liquid reservoir 112 and is cooled to the temperature of the cryogenic liquid 104 by immersion in the cryogenic liquid 104.

[0019] The object being cooled 102 is, for example, a superconducting device with a superconducting coil, such as a superconducting motor or a superconducting magnet. Alternatively, the object being cooled 102 can also be other devices that require ultra-low temperatures as their operating environment.

[0020] In this embodiment, the cryogenic liquid 104 is a refrigerant having a boiling point of 10 K or higher, such as liquid hydrogen. Alternatively, the cryogenic liquid 104 can be liquid neon. The cryogenic liquid 104 can also be a refrigerant having a boiling point lower than that of nitrogen (approximately 77 K).

[0021] Furthermore, the cryogenic system 100 includes a cryogenic liquid supply line 120 and an evaporation gas discharge line 130 connected to the cryogenic liquid storage tank 112. Cryogenic liquid 104 (e.g., liquid hydrogen) can be supplied to the cryogenic liquid storage tank 112 via the cryogenic liquid supply line 120 from a cryogenic liquid source (not shown). The cryogenic liquid 104 can vaporize due to cooling by the cooled object 102 or by heat intrusion from outside the cryogenic liquid storage tank 112. The resulting evaporation gas (e.g., hydrogen) BOG may cause an increase in the internal pressure of the cryogenic liquid storage tank 112. The evaporation gas discharge line 130 is provided for releasing the internal pressure of the cryogenic liquid storage tank 112. By recovering the evaporation gas BOG or discharging it to the external environment (e.g., room temperature atmospheric pressure environment) via the evaporation gas discharge line 130, the internal pressure of the cryogenic liquid storage tank 112 can be maintained at an appropriate level (e.g., a positive pressure higher than atmospheric pressure by a specified pressure).

[0022] The evaporation gas discharge pipeline 130 includes an evaporation gas re-condensation device 10, an inlet path 132 for introducing evaporation gas BOG from the cryogenic liquid storage tank 112 into the evaporation gas re-condensation device 10, and an external discharge path 134 for discharging evaporation gas BOG from the evaporation gas re-condensation device 10 to the outside.

[0023] The evaporative gas recondensation unit 10 and the cryogenic liquid storage tank 112 are separate units. The inlet path 132 connecting the two can be piping (e.g., flexible or rigid pipe) suitable for conveying the cryogenic medium (i.e., evaporative gas). The external discharge path 134 can also be piping suitable for conveying the cryogenic medium. A recovery tank 136 for recovering the discharged evaporative gas (BOG) can be connected to the external discharge path 134.

[0024] The evaporative gas recondensation device 10 includes: a cryogenic thermostat 12; a recondenser 14 housed in the cryogenic thermostat 12 and recondensing the evaporative gas BOG; and an ultra-low temperature refrigerator 16 mounted on the cryogenic thermostat 12 and cooling the recondenser 14.

[0025] The cryostat 12 is a vacuum-insulated container configured to provide an internal vacuum environment 13. The cryostat 12 includes a vacuum wall 12a that isolates and surrounds the vacuum environment 13 from the external environment. Within the vacuum insulation layer inside the vacuum wall 12a, an insulation structure such as a multilayer insulation (MLI) can be provided to improve insulation performance.

[0026] The cryogenic thermostat 12 has an evaporating gas inflow path 18 and an evaporating gas outflow path 20. The evaporating gas inflow path 18 is connected to the inlet path 132 of the evaporating gas discharge line 130, allowing the evaporating gas BOG to flow from the inlet path 132 into the recondenser 14. The evaporating gas inflow path 18 may have a gas inlet 18a on the vacuum wall 12a, which serves as the interface for connecting the cryogenic thermostat 12 to the inlet path 132, and the gas inlet 18a is detachably connected to the inlet path 132.

[0027] Furthermore, the evaporation gas outlet path 20 is connected to the external outlet path 134 of the evaporation gas outlet pipe 130, enabling the evaporation gas BOG to flow from the recondenser 14 to the external outlet path 134. The evaporation gas outlet path 20 may have a gas outlet 20a in the vacuum wall 12a, which serves as an interface for connecting the cryostat 12 to the external outlet path 134, and the gas outlet 20a is detachably connected to the external outlet path 134.

[0028] Thus, the evaporating gas inflow path 18, the recondenser 14, and the evaporating gas outflow path 20 form an evaporating gas flow path isolated from the vacuum environment 13 within the cryostat 12.

[0029] The recondenser 14 is a heat exchanger that recondenses the evaporated gas BOG by exchanging heat with it. The recondenser 14 is made, for example, of pure copper (e.g., oxygen-free copper, ductile copper, etc.) or other highly thermally conductive metals. Furthermore, the evaporated gas inlet path 18 and the evaporated gas outlet path 20 connected to the recondenser 14 can be made of a metal with a lower thermal conductivity than the recondenser 14 (e.g., stainless steel).

[0030] As shown in the figure, the recondenser 14 can be supported on the cryostat 12 by a support body 22 made of insulating material (e.g., glass fiber reinforced resin). Alternatively, the support body 22 may not be provided, and the recondenser 14 can be supported on the cryostat 12 by an ultra-low temperature refrigerator 16 (in this case, the recondenser 14 can be fixed to the cooling platform 16c described later).

[0031] The cryogenic refrigerator 16 is a single-stage cryogenic refrigerator capable of providing cooling temperatures above 10K. The cooling temperature provided by the cryogenic refrigerator 16 is lower than the boiling point of the cryogenic liquid 104 used; for example, when liquid hydrogen is used as the cryogenic liquid 104, it can be lower than its boiling point (approximately 20K).

[0032] The cryogenic refrigerator 16 includes a drive motor 16a, a cylinder 16b, and a cooling platform 16c. The cryogenic refrigerator 16 is mounted on a cryostat 12, with the drive motor 16a positioned externally to the cryostat 12 and the cooling platform 16c positioned internally. As shown, the cryogenic refrigerator 16 can be positioned on top of the cryostat 12. The cooling platform 16c is thermally connected to the recondenser 14 (e.g., in contact with the outer surface of the recondenser 14), and cools the recondenser 14 via the cooling platform 16c.

[0033] As an example, the cryogenic refrigerator 16 can be a Gifford-McMahon (GM) refrigerator. A cylinder 16b connects a drive motor 16a and a cooling platform 16c, and inside the cylinder 16b is a displacement device that reciprocates within the cylinder 16b driven by the drive motor 16a. The displacement device contains a regenerator, and a working gas expansion space is formed within the cooling platform 16c, whose volume changes with the movement of the displacement device. Typically, the cooling platform 16c is made of a high thermal conductivity metal material, such as pure copper, while the cylinder 16b is made of a metal material with a lower thermal conductivity (e.g., stainless steel). The cryogenic refrigerator 16 is configured such that, when the drive motor 16a is running, periodic volume changes and synchronous working gas pressure variations occur in the expansion space, thereby generating a refrigeration cycle. Thus, the cryogenic refrigerator 16 can cool the cooling platform 16c and the recondenser 14 to a desired cooling temperature (e.g., approximately 10–20 K).

[0034] In addition, the cryogenic refrigerator 16 is not limited to GM refrigerators, but can also be other types of cryogenic refrigerators, such as pulse tube refrigerators, Stirling refrigerators, etc.

[0035] Typically, when a two-stage cryogenic refrigerator is installed within a cryostat, a heat shield attached to the first-stage cooling section is required to suppress heat intrusion from the outside into the second-stage cooling section. This can complicate the internal structure of the cryostat. In contrast, by mounting a single-stage cryogenic refrigerator 16 within the cryostat 12, the internal structure of the cryostat 12 can be simplified.

[0036] The evaporative gas recondensation device 10 receives evaporative gas (BOG) from the cryogenic liquid storage tank 112 via the inlet path 132 and the evaporative gas inflow path 18, and transfers a portion of it to the recondenser 14. The remaining BOG is then recondensed in the recondenser 14, and recovered to the recovery tank 136 or released into the external environment via the evaporative gas outlet path 20 and the external discharge path 134. The liquefied BOG, i.e., cryogenic liquid 104 (e.g., liquid hydrogen), which is recondensed in the recondenser 14, returns from the recondenser 14 to the cryogenic liquid storage tank 112 via the evaporative gas inflow path 18 and the inlet path 132.

[0037] To facilitate the outflow of cryogenic liquid 104 from recondenser 14, the evaporation gas inflow path 18 can be positioned lower than recondenser 14. As shown, the evaporation gas inflow path 18 can slope downwards from recondenser 14 toward gas inlet 18a. The recondensed evaporation gas BOG can flow downwards along this slope by gravity. This facilitates the resupply of cryogenic liquid 104 from evaporation gas recondensation device 10 to cryogenic liquid storage tank 112.

[0038] Furthermore, to prevent the evaporated gas after recondensation from flowing from the recondenser 14 into the evaporated gas outlet path 20, the evaporated gas outlet path 20 can be positioned higher than the recondenser 14. As shown in the figure, the evaporated gas outlet path 20 can slope upwards from the recondenser 14 toward the gas outlet 20a.

[0039] According to the embodiment, an evaporation gas recondensation device that is easy to add to the cryogenic system 100 later can be provided. By installing the evaporation gas recondensation device 10 on the evaporation gas discharge pipeline 130 for releasing the internal pressure of the cryogenic liquid storage tank 112, the evaporation gas recondensation device 10 can be added as an auxiliary device to the cryogenic cooling device 110 that does not originally have the evaporation gas recondensation device 10.

[0040] As an optional feature, the evaporative gas recondensation device 10 may include a pressure sensor 28 for measuring the pressure of the evaporative gas BOG. ​​The pressure sensor 28 may be located on the recondenser 14, the evaporative gas inflow path 18, or the evaporative gas outflow path 20 to measure the pressure of the evaporative gas BOG.

[0041] Pressure sensor 28 and its associated components, such as electrical wiring, may become a heat transfer path from the external environment to the evaporative gas recondensation unit 10. Through this heat transfer path, heat can eventually penetrate into the cryogenic liquid storage tank 112. To reduce this heat intrusion, pressure sensor 28 can measure the pressure of the evaporative gas BOG at a location as far away from the cryogenic liquid storage tank 112 as possible (e.g., at the evaporative gas outflow path 20).

[0042] Furthermore, the evaporative gas recondensation device 10 may include a controller 30 configured to control the refrigeration output of the cryogenic refrigerator 16 based on the output of the pressure sensor 28. The controller 30 is connected to the pressure sensor 28 to receive a measured pressure signal representing the evaporative gas BOG as measured by the pressure sensor 28. The controller 30 receives the measured pressure signal from the pressure sensor 28 and controls the rotational speed of the drive motor 16a of the cryogenic refrigerator 16 based on this measured pressure signal. By increasing the rotational speed of the drive motor 16a, the refrigeration output of the cryogenic refrigerator 16 can be increased, reducing the temperature of the cooling stage 16c and the recondenser 14 and / or the pressure of the BOG. ​​Conversely, by decreasing the rotational speed of the drive motor 16a, the refrigeration output of the cryogenic refrigerator 16 can be decreased, increasing the temperature of the cooling stage 16c and the recondenser 14 and / or the pressure of the BOG.

[0043] For example, the controller 30 compares the measured pressure of the evaporating gas BOG with a first pressure threshold. When the measured pressure exceeds the first pressure threshold, the refrigeration output of the cryogenic refrigerator 16 can be increased; conversely, when the measured pressure is below the first pressure threshold, the refrigeration output of the cryogenic refrigerator 16 can be maintained or decreased. The first pressure threshold can be appropriately set based on the appropriate pressure range of the cryogenic liquid storage tank 112, and based on the designer's empirical knowledge, experiments, or simulations. For example, the first pressure threshold can be the upper limit of the appropriate pressure range of the cryogenic liquid storage tank 112.

[0044] Therefore, for example, when the operation of the cooled object 102 causes a large amount of vaporized cryogenic liquid 104 in the cryogenic liquid storage tank 112, and the evaporating gas BOG pressure increases, the recondensing capacity of the recondenser 14 can be increased, and the pressure of the evaporating gas BOG can be reduced. This helps to maintain the internal pressure of the cryogenic liquid storage tank 112 at an appropriate level.

[0045] Furthermore, the controller 30 can compare the measured pressure of the evaporating gas BOG with a second pressure threshold. When the measured pressure exceeds the second pressure threshold, the cryogenic refrigerator 16 is activated; conversely, when the measured pressure falls below the second pressure threshold, the operation of the cryogenic refrigerator 16 is stopped. The second pressure threshold can be a pressure value smaller than the first pressure threshold. The second pressure threshold can be based on an appropriate pressure range for the cryogenic liquid storage tank 112 and can be appropriately set according to the designer's empirical knowledge or through experiments or simulations. For example, the second pressure threshold can be the lower limit of an appropriate pressure range for the cryogenic liquid storage tank 112.

[0046] Therefore, when the amount of vaporized cryogenic liquid 104 in the cryogenic liquid storage tank 112 is sufficiently small, the cryogenic refrigerator 16 can be stopped, and the recondensation function of the evaporative gas recondensation device 10 can be turned off. This helps to improve the energy-saving performance of the cryogenic system 100.

[0047] In the internal structure of the controller 30, the hardware structure can be implemented using components or circuits, such as a computer's CPU or memory, while the software structure can be implemented using computer programs, etc. However, it is appropriately depicted in the figure as functional modules implemented through their cooperation. Those skilled in the art will certainly understand that these functional modules can be implemented in various forms through a combination of hardware and software.

[0048] Additionally, the evaporative gas recondenser 10 can be equipped with a temperature sensor to replace or be used in conjunction with the pressure sensor 28. This temperature sensor is used to measure the temperature of the evaporative gas BOG. ​​The temperature sensor can be installed on the recondenser 14 or the cooling platform 16c to measure its temperature.

[0049] The controller 30 can be configured to control the cooling output of the cryogenic refrigerator 16 based on the output of the temperature sensor. For example, the controller 30 compares the measured temperature of the evaporating gas BOG with a first temperature threshold. When the measured temperature exceeds the first temperature threshold, the controller can increase the cooling output of the cryogenic refrigerator 16. Conversely, when the measured temperature is below the first temperature threshold, the controller can maintain or decrease the cooling output of the cryogenic refrigerator 16. Furthermore, the controller 30 compares the measured temperature of the evaporating gas BOG with a second temperature threshold that is lower than the first temperature threshold. When the measured temperature exceeds the second temperature threshold, the controller can operate the cryogenic refrigerator 16. Conversely, when the measured temperature is below the second temperature threshold, the controller can stop the operation of the cryogenic refrigerator 16.

[0050] Figure 2 This is a schematic diagram showing an example of an ultra-low temperature refrigerator 16 provided in the embodiment, which is installed in the cryogenic thermostat 12 of the evaporating gas recondenser 10. The ultra-low temperature refrigerator 16 can be movably mounted on the cryogenic thermostat 12 relative to the recondenser 14, so as to make or break thermal contact with the recondenser 14.

[0051] Therefore, the cryostat 12 may include a bellows 24 that connects the drive motor 16a of the cryogenic refrigerator 16 to the vacuum wall 12a of the cryostat 12. The bellows 24 connects the cryogenic refrigerator 16 to the cryostat 12 to maintain the airtightness of the vacuum environment 13. The cylinder 16b of the cryogenic refrigerator 16 extends from the drive motor 16a through the bellows 24, and the cooling platform 16c is disposed inside the cryostat 12.

[0052] Furthermore, a movable mechanism 26 is provided externally within the cryostat 12. By operating the movable mechanism 26, the bellows 24 extends and retracts, and the cryogenic refrigerator 16 moves relative to the cryostat 12, thereby enabling the cooling platform 16c to come into thermal contact with or separate from the recondenser 14. The movable mechanism 26 may have a suitable drive source, such as hydraulic, pneumatic, electric motor, electromagnet, etc., or it may be a manually operated movable mechanism.

[0053] As described above, the operation of the cryogenic refrigerator 16 can be stopped under the control of the controller 30. During the period when the cryogenic refrigerator 16 is not in operation, the thermal contact between the cryogenic refrigerator 16 and the recondenser 14 can be cut off by the operation of the movable mechanism 26. In this way, the intrusion of heat from the external environment to the recondenser 14 through the heat transfer path of the non-operating cryogenic refrigerator 16 can be suppressed.

[0054] Figure 3 This is a schematic diagram illustrating another example of the cryogenic system 100 according to the embodiment. In the above embodiment, the cryogenic liquid 104, after being recondensed in the evaporating gas recondensation device 10, returns to the cryogenic liquid storage tank 112 through the evaporating gas inflow path 18 and the inlet path 132, but... Figure 3 In the example shown, in addition to the evaporating gas inflow path 18, a liquid supply path 32 is also provided in the evaporating gas recondensation device 10.

[0055] Liquid supply path 32 is connected to recondenser 14, enabling the re-condensation of evaporated gas (BOG) in recondenser 14 to be re-supplied to cryogenic liquid storage tank 112. Liquid supply path 32 merges into cryogenic liquid supply line 120 leading to cryogenic liquid storage tank 112. In this way, the re-supply of cryogenic liquid 104 from evaporated gas recondensation device 10 to cryogenic liquid storage tank 112 becomes convenient.

[0056] As shown in the figure, a portion of the cryogenic liquid supply line 120 can pass through the interior of the cryogenic thermostat 12, and the recondenser 14 can be positioned above this portion of the cryogenic liquid supply line 120. The recondensed evaporated gas BOG can flow down from the recondenser 14 through the liquid supply path 32 into the cryogenic liquid supply line 120 by gravity.

[0057] As an optional solution, a valve 34 can be installed on the liquid supply path 32. The valve 34 can be an on / off valve for opening and closing the liquid supply path 32, or a check valve to prevent backflow in the liquid supply path 32.

[0058] Figure 4This is a schematic diagram illustrating another example of the evaporative gas recondensation apparatus 10 according to the embodiment. As shown, the evaporative gas inflow path 18 may have a tortuous pipe connecting the recondenser 14 to the gas inlet 18a. The tortuous pipe may have a two-dimensional tortuous shape that bends along a plane. Alternatively, the tortuous pipe may have a three-dimensional tortuous shape, such as a spiral shape. That is, the tortuous pipe may include a spiral pipe. The tortuous pipe can absorb the thermal contraction accompanying cryogenic cooling. Similarly, the evaporative gas outflow path 20 and the liquid supply path 32 may also have tortuous pipes.

[0059] The present invention has been described above with reference to embodiments. The present invention is not limited to the above embodiments, and various design changes can be made. Those skilled in the art will understand that various modifications can be implemented, and these modifications are also included within the scope of the present invention. The various features described for one embodiment can also be applied to other embodiments. New embodiments resulting from combinations possess the effects of the combined embodiments.

[0060] In the above embodiments, the example illustrates a case where the evaporation gas discharge line 130 is directly connected to the cryogenic liquid storage tank 112. However, in some embodiments, the evaporation gas discharge line 130 may also be connected to an auxiliary device provided in the cryogenic liquid storage tank 112. For example, a booster pump that generates high-pressure gas by pressurizing the cryogenic liquid 104 to vaporize it may be provided in the cryogenic liquid storage tank 112, and the evaporation gas discharge line 130 may be connected to this booster pump. The evaporation gas recondensation device 10 involved in the embodiments may be installed on such an evaporation gas discharge line 130.

[0061] In the above embodiments, the case of a single-stage cryogenic refrigerator 16 is used as an example for explanation. However, in some embodiments, the cryogenic refrigerator 16 may also be a two-stage or multi-stage cryogenic refrigerator. The cryogenic refrigerator 16 can be any type of cryogenic refrigerator, such as a GM refrigerator, a pulse tube refrigerator, a Stirling refrigerator, etc.

[0062] According to the embodiments, the present invention has been described using specific wording, but the embodiments only show one aspect of the principle and application of the present invention. In the embodiments, many variations or configuration changes are allowed without departing from the spirit of the present invention as defined in the claims.

[0063] Industrial availability

[0064] This invention can be applied to the field of evaporative gas recondensation devices.

[0065] Symbol Explanation

[0066] 10-Evaporated gas recondensation device, 12-Low temperature thermostat, 14-Recondenser, 16-Ultra-low temperature refrigerator, 18-Evaporated gas inflow path, 20-Evaporated gas outflow path, 30-Controller, 32-Liquid supply path, 104-Ultra-low temperature liquid, 112-Ultra-low temperature liquid storage tank, 120-Ultra-low temperature liquid supply pipeline, 130-Evaporated gas discharge pipeline, 132-Inlet path, 134-External discharge path, BOG-Evaporated gas.

Claims

1. An evaporating gas recondensation device, which can be installed on an evaporating gas discharge pipeline for releasing internal pressure in a cryogenic liquid storage tank, the evaporating gas discharge pipeline comprising: an inlet path for introducing evaporating gas from the cryogenic liquid storage tank into the evaporating gas recondensation device; and an external discharge path for discharging the evaporating gas from the evaporating gas recondensation device to the outside; The evaporation gas re-condensation device is characterized by having: Low-temperature thermostat; and A recondenser, housed within the cryogenic thermostat, is used to recondense the evaporated gas. The low-temperature thermostat has the following features: An evaporating gas inflow path, connected to the inlet path of the evaporating gas discharge pipe, allows the evaporating gas to flow from the inlet path into the recondenser; and The evaporation gas outflow path, connected to the external discharge path of the evaporation gas discharge pipeline, enables the evaporation gas to flow from the recondenser to the external discharge path.

2. The evaporation gas re-condensation device according to claim 1, characterized in that, The boiling point of the evaporated gas is above 10K.

3. The evaporation gas re-condensation device according to claim 1, characterized in that, It also features a single-stage cryogenic refrigerator, which is mounted on the cryogenic thermostat to cool the recondenser.

4. The evaporation gas re-condensation device according to claim 3, characterized in that, It also has: Sensors for measuring the pressure or temperature of the evaporated gas; and The controller is configured to control the refrigeration output of the cryogenic refrigerator based on the output of the sensor.

5. The evaporation gas re-condensation device according to claim 4, characterized in that, The controller is configured to: compare the output of the sensor with a first threshold; when the output of the sensor exceeds the first threshold, increase the cooling output of the cryogenic refrigerator; when the output of the sensor is below the first threshold, maintain or decrease the cooling output of the cryogenic refrigerator.

6. The evaporation gas re-condensation apparatus according to claim 5, characterized in that, The controller is configured to: compare the output of the sensor with a second threshold that is less than the first threshold; when the output of the sensor exceeds the second threshold, start the cryogenic refrigerator; when the output of the sensor is lower than the second threshold, stop the operation of the cryogenic refrigerator.

7. The evaporative gas recondensation apparatus according to any one of claims 1 to 6, characterized in that, It also has a liquid supply path connected to the recondenser, which enables the evaporated gas, after being recondensed in the recondenser, to be supplied to the cryogenic liquid storage tank.

8. The evaporation gas re-condensation apparatus according to claim 7, characterized in that, The liquid supply path merges into the cryogenic liquid supply pipeline leading to the cryogenic liquid storage tank.

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