Low-temperature valve heat leakage testing equipment and testing method

Abstract

The invention relates to the technical field of low-temperature valve testing, in particular to low-temperature valve heat leakage testing equipment and method.The equipment comprises a double-chamber container internally provided with a testing chamber and a storage tank chamber which are isolated, a liquid nitrogen storage tank is located in the storage tank chamber and connected with a blow-down pipe and a liquid inlet pipe which penetrate out of the storage tank chamber, and the liquid nitrogen storage tank is connected with a liquid outlet pipe; the test air inlet pipe is communicated with a valve to be tested or a replacement pipeline; the evaporation measurement device is communicated with the test gas outlet pipe and the liquid nitrogen storage tank, the test gas outlet pipe is located in the test cavity and used for being communicated with a valve to be tested or a replacement pipeline, and the evaporation measurement device is used for measuring the evaporation capacity of liquid nitrogen; the vacuum generating device is communicated with the testing chamber and the storage tank chamber through a vacuumizing pipe, and the vacuum degree of the testing chamber and the vacuum degree of the storage tank chamber are independently controlled. The device effectively eliminates the influence of heat leakage of the device and environmental factors, achieves the accurate testing of the heat leakage of the low-temperature valve, achieves the more accurate evaluation of the performance of the valve, and is suitable for the performance evaluation scene of a cryogenic medium valve.

Description

Technical Field

[0001] This application relates to the field of cryogenic valve testing technology, and in particular to a cryogenic valve heat leakage testing device and testing method. Background Technology

[0002] Cryogenic valves are special valves that operate in extremely low temperature environments. They are suitable for media temperatures ranging from -40℃ to -253℃ and are widely used in high-tech fields such as aerospace, energy, and medical. They are mainly used to control the on / off and flow of cryogenic media such as liquid nitrogen, liquid hydrogen, and liquefied helium. Their core function is to maintain structural stability and sealing performance under ultra-low temperature conditions. They must withstand the test of material low-temperature brittleness and prevent unnecessary heat exchange between the cryogenic medium and the valve assembly. They are key components to ensure the safe operation of cryogenic systems.

[0003] The heat leakage performance of cryogenic valves directly affects the operating efficiency and safety of cryogenic systems. Heat leakage causes the cryogenic medium on the low-temperature side of the valve to evaporate due to the absorption of external heat. This not only increases the frequency of refrigerant replenishment and energy consumption, but may also lead to abnormal system pressure due to excessive evaporation, or even equipment overpressure instability. Simultaneously, the temperature gradient generated by heat leakage may cause deformation of the valve sealing surface and a decrease in sealing performance, exacerbating the risk of medium leakage. Therefore, accurate detection of the heat leakage characteristics of cryogenic valves is a core step in evaluating their design rationality, material compatibility, and sealing reliability.

[0004] Existing low-temperature valve heat leakage detection devices cannot eliminate the interference of external environmental heat on the measurement results due to heat leakage in their own pipelines, resulting in large data errors and making it difficult to accurately calculate the heat leakage. Summary of the Invention

[0005] To address the issues of heat leakage in the pipeline itself and significant external environmental interference leading to large data errors, this application provides a low-temperature valve heat leakage testing device and method.

[0006] The low-temperature valve heat leakage testing equipment and testing method provided in this application adopt the following technical solution: On the one hand, a low-temperature valve heat leakage testing device includes: A dual-chamber container, with an isolated test chamber and a storage tank chamber inside, wherein the test chamber is used to place the valve to be tested or the replacement pipe; A liquid nitrogen storage tank is located in the storage tank chamber. The liquid nitrogen storage tank is connected to an vent pipe and a liquid inlet pipe that extend out of the storage tank chamber, as well as a test gas inlet pipe for connecting to the valve under test or the replacement pipeline. An evaporation measuring device is connected to a test outlet pipe and the liquid nitrogen storage tank. The test outlet pipe is located in the test chamber and is used to connect to the valve to be tested or a replacement pipe. The evaporation measuring device is used to measure the amount of liquid nitrogen evaporation. A vacuum generating device is connected to the test chamber and the storage tank chamber respectively through a vacuum tube, and independently controls the vacuum level of the test chamber and the storage tank chamber.

[0007] By adopting the above technical solution, the dual-chamber container isolates the test chamber from the storage tank chamber, avoiding heat exchange interference between the two and providing an independent testing environment. The liquid nitrogen storage tank is filled with liquid nitrogen and discharged gas through the vent pipe and liquid inlet pipe. Together with the test gas inlet pipe, it can stably deliver liquid nitrogen to the valve under test or the replacement pipeline, ensuring the continuity of the test medium supply. The evaporation measurement device is connected to the test gas outlet pipe and the liquid nitrogen storage tank, which can accurately capture the amount of liquid nitrogen evaporation and provide key data for heat leakage calculation. The vacuum generating device independently controls the vacuum degree of the two chambers. It can simulate different working conditions by adjusting the vacuum degree of the test chamber, and can maintain a specific vacuum state in the storage tank chamber to reduce external interference such as heat radiation. Combined with the synergistic effect of each part, it effectively eliminates the influence of heat leakage of the device itself and environmental factors, and realizes accurate testing of heat leakage of cryogenic valves, thereby more accurately evaluating valve performance. It is suitable for performance evaluation scenarios of cryogenic medium valves.

[0008] Optionally, the evaporation measuring device includes a gas collection mechanism and a heater. The gas collection mechanism and the heater are connected to the test chamber through a gas outlet pipe, and a flow meter is connected to the gas outlet pipe.

[0009] By adopting the above technical solution, the gas collection mechanism in the evaporation measurement device can effectively collect the gas generated by liquid nitrogen evaporation during the test, avoiding gas loss that could affect the measurement accuracy; the heater can heat the collected low-temperature gas to bring its temperature close to room temperature, ensuring the stability of subsequent flow measurement; and the conversion of evaporation amount into low-temperature valve heat leakage provides high-precision data support, ensuring the reliability of heat leakage test results.

[0010] Optionally, the vacuum level inside the storage tank is maintained below 0.01 Pa.

[0011] By adopting the above technical solution, the storage tank chamber is in a high vacuum state. At this time, the gas molecule density in the chamber is extremely low, which can significantly reduce the gas heat conduction and heat convection effects, and minimize the heat transferred from the external environment to the liquid nitrogen storage tank through the gas medium. At the same time, the high vacuum environment can effectively reduce the scattering and absorption of heat radiation by gas molecules, further reducing the heat interference caused by heat radiation. This significantly reduces the non-testable evaporation loss of the liquid nitrogen storage tank caused by external heat sources, ensuring that the change in liquid nitrogen evaporation in subsequent measurements mainly reflects the heat leakage of the valve under test, laying the foundation for accurate calculation of heat leakage and improving the reliability and accuracy of the test results.

[0012] Optionally, the storage tank chamber is equipped with a molecular sieve desiccant.

[0013] By adopting the above technical solution, the molecular sieve desiccant installed in the tank chamber can efficiently adsorb residual water vapor and other trace gaseous impurities in the chamber, preventing these impurities from condensing into solid or liquid states due to temperature changes in a high vacuum environment. This prevents them from adhering to the surface of the liquid nitrogen tank, forming thermal bridges, or blocking pipelines, thereby stabilizing the high vacuum state of the tank chamber, reducing interference from heat radiation and heat conduction caused by vacuum fluctuations, and ensuring that the non-testable evaporation loss of the liquid nitrogen tank is at a stable and extremely low level. This provides a stable environmental basis for the subsequent accurate calculation of the heat leakage of the valve under test through the difference in evaporation, further improving the reliability of the test results.

[0014] Optionally, the bottom wall of the storage tank chamber is provided with a hollow load-bearing column, the load-bearing column is filled with heat insulation material, and the liquid nitrogen storage tank is installed on the load-bearing column.

[0015] By adopting the above technical solution, the hollow load-bearing column on the bottom wall of the tank cavity can provide stable support for the liquid nitrogen storage tank, ensuring its installation stability within the tank cavity. The hollow structure also reduces the heat conduction path of the solid material. Simultaneously, the insulation material filled inside the load-bearing column, with its low thermal conductivity, further blocks the transfer of heat from the bottom wall of the tank cavity to the liquid nitrogen storage tank through the load-bearing column. This effectively reduces heat conduction interference caused by structural contact, preventing external heat from entering the liquid nitrogen storage tank through this path and causing non-testable liquid nitrogen evaporation. This ensures that changes in the amount of liquid nitrogen evaporation more accurately reflect the heat leakage of the valve under test, improving the reliability of the test results.

[0016] Optionally, the liquid nitrogen storage tank is provided with a connector on its outer bottom wall, and the connector is sleeved on the load-bearing column.

[0017] By adopting the above technical solution, the insertion pipe on the bottom wall of the liquid nitrogen storage tank is sleeved on the load-bearing column. The sleeve structure enables the rapid positioning and installation of the liquid nitrogen storage tank, ensuring its stability in the storage tank chamber and avoiding the failure of the connection pipe seal or position displacement caused by the shaking of the storage tank during the test.

[0018] Optionally, the liquid nitrogen storage tank and all other pipes except the vacuum tube are covered with an insulation layer.

[0019] By adopting the above technical solution, the liquid nitrogen storage tank and other pipelines except for the vacuum tube are covered with an insulation layer. The insulation properties of the insulation layer can significantly reduce the transfer of heat from the external environment to the liquid nitrogen storage tank and the pipelines transporting the cryogenic medium, thereby reducing non-testable evaporation of liquid nitrogen due to the absorption of external heat. At the same time, it can suppress the heat exchange between the cryogenic medium in the pipeline and the outside environment, avoid heat leakage interference caused by temperature difference in the pipeline itself, and control the heat leakage of the pipeline to an extremely low level. This ensures that the amount of liquid nitrogen evaporation detected by the evaporation measurement device mainly comes from the heat leakage of the valve under test, rather than the heat exchange of the storage tank or pipeline itself. This provides a reliable measurement basis for accurately calculating the heat leakage of the valve and improves the accuracy of the test results.

[0020] Optionally, the insulation layer may include aluminum foil and / or fiberglass paper.

[0021] By employing the above technical solution, aluminum foil, with its high reflectivity, effectively reflects external heat radiation, reducing the transfer of heat to the liquid nitrogen storage tank and pipelines. Fiberglass paper, with its low thermal conductivity, significantly inhibits heat conduction, blocking the heat transfer path through solid materials. When used alone or in combination, these two materials create a synergistic insulation effect across both heat radiation and conduction, enhancing the insulation capacity of the liquid nitrogen storage tank and pipelines. This further reduces non-testable liquid nitrogen evaporation caused by external heat intrusion, ensuring that the evaporation measurement device more accurately corresponds to the heat leakage characteristics of the valve under test. This provides a more reliable basis for heat leakage calculation and improves the accuracy of test results.

[0022] Optionally, the insulation layer has a thickness of 15-25 mm.

[0023] By adopting the above technical solution, the insulation layer thickness is 15-25mm. This thickness provides sufficient stacking space for aluminum foil and / or fiberglass paper to extend the heat transfer path and enhance the blocking effect against heat radiation and heat conduction. Too thin a layer would make it difficult to form an effective heat barrier, while too thick a layer could increase the size and weight of the equipment and reduce the marginal insulation benefits. At the same time, a reasonable thickness design can balance the insulation performance and the practicality of the equipment. This ensures that while reducing the transfer of external heat to the liquid nitrogen storage tank and pipelines, the excessively thick covering layer will not affect the pipeline connection or the internal space layout of the equipment. This stabilizes the non-testing heat leakage of the storage tank and pipelines, making the liquid nitrogen evaporation captured by the evaporation measurement device more accurately correspond to the heat leakage characteristics of the valve under test, and providing a reliable basis for heat leakage calculation.

[0024] Optionally, the density of the insulation layer is 25-35 layers / cm.

[0025] By adopting the above technical solution, a dense multi-layer structure is formed within a unit length. Each layer of aluminum foil and / or fiberglass paper can serve as an independent thermal barrier. By increasing the number of heat-reflecting interfaces, the reflection and absorption of heat radiation are enhanced. At the same time, the dense interlayer gaps can further weaken the air convection and heat conduction paths, significantly improving the overall thermal insulation performance. This density avoids insufficient thermal resistance (ineffective heat transfer) caused by too few layers, and also prevents interlayer compression (damaging the thermal insulation effect of the interlayer air layer) that may be caused by too many layers. In conjunction with the 15-25mm wrapping thickness, the thermal insulation efficiency of the insulation material is maximized in a limited space, reducing the transfer of external heat to the liquid nitrogen storage tank and pipelines. This reduces non-testable liquid nitrogen evaporation loss, ensuring that the evaporation amount detected by the evaporation measurement device more accurately corresponds to the heat leakage characteristics of the valve under test, providing a reliable guarantee for heat leakage calculation.

[0026] Optionally, the liquid nitrogen storage tank is equipped with a liquid nitrogen level sensor for detecting the liquid nitrogen level.

[0027] By adopting the above technical solution, the liquid nitrogen level sensor on the liquid nitrogen storage tank can detect and provide feedback on the liquid nitrogen level in real time. This allows for precise control of the liquid nitrogen level during the test to reach the valve seat height of the valve under test, ensuring a stable and consistent contact state between the cryogenic medium and the valve, and avoiding deviations in test conditions caused by excessively high or low liquid levels. Simultaneously, by monitoring liquid level changes in real time, abnormal evaporation or consumption of liquid nitrogen can be detected promptly, aiding in the determination of whether there is additional heat leakage from non-tested valves (such as heat leakage from the storage tank or pipeline itself). This facilitates timely troubleshooting of interfering factors, ensuring the continuity and stability of the test, providing a stable liquid level reference for the evaporation measurement device, reducing measurement errors in evaporation caused by liquid level fluctuations, and thus improving the accuracy of heat leakage calculation.

[0028] On the other hand, a method for testing the heat leakage of a cryogenic valve, applied to the aforementioned cryogenic valve heat leakage testing equipment, includes the following steps: The valve to be tested is installed in the test chamber, and the vacuum generator is used to evacuate the test chamber and the storage tank chamber to the standard requirements. Liquid nitrogen is injected into the liquid nitrogen storage tank, the liquid level is controlled to the height of the valve seat of the valve to be tested, the vent pipe is closed, and the evaporation amount Q1 after stabilization is recorded using the evaporation measuring device; Remove the valve to be tested and replace it with the replacement pipe. Use the vacuum generator to evacuate the test chamber to the standard requirements. Liquid nitrogen is injected into the liquid nitrogen storage tank to fill the replacement pipe. The vent pipe is then closed, and the evaporation amount Q2 after stabilization is recorded using the evaporation measuring device. Heat loss calculation: ΔQ=Q1-Q2, and the actual heat loss value is calculated by combining the latent heat of liquid nitrogen vaporization.

[0029] By adopting the above technical solution, the valve to be tested is first installed in the vacuum-sealed test chamber, the liquid nitrogen level is controlled to the height of the valve seat and the evaporation amount Q1 is recorded, and then the valve is replaced with a pipeline and the evaporation amount Q2 is recorded under the same vacuum conditions. The heat leakage is calculated using the difference ΔQ=Q1-Q2, which can effectively eliminate the background evaporation amount caused by the heat leakage of the test system (such as pipelines and storage tanks) and environmental interference, so that the result only reflects the heat leakage characteristics of the valve under test. The vacuuming step ensures that the test chamber and the storage tank chamber are in a stable vacuum environment, reducing heat radiation and heat conduction interference. Controlling the liquid nitrogen level consistently ensures the uniformity of test conditions and avoids the deviation of evaporation amount caused by liquid level differences. Combining the latent heat of vaporization of liquid nitrogen to convert the actual heat leakage value, the evaporation data is converted into an intuitive heat value, realizing the accurate quantitative evaluation of the heat leakage performance of cryogenic valves. The whole process significantly improves the accuracy and reliability of the test results by controlling variables and eliminating background interference, and is suitable for efficient detection of the heat leakage characteristics of cryogenic valves under different operating conditions.

[0030] In summary, this application includes at least one of the following beneficial technical effects: 1. Through multiple measures such as dual-chamber container isolation design, independent control of the vacuum degree of the two chambers by the vacuum generator (the vacuum degree of the storage tank chamber is below 0.01Pa, and the vacuum degree of the test chamber is adjustable), and covering the storage tank and pipeline with a high-efficiency heat insulation layer, the environmental thermal interference such as heat radiation, heat conduction, and heat convection can be minimized. At the same time, the non-testable heat leakage of the system itself (storage tank and pipeline) is suppressed, so that the amount of liquid nitrogen evaporation captured by the evaporation measurement device mainly reflects the heat leakage characteristics of the valve under test. From the hardware design level, it provides a measurement environment with extremely low interference for heat leakage testing, which significantly improves the accuracy of the test results.

[0031] 2. By adopting the "comparative measurement of the valve under test and the replacement pipeline" mode, the difference ΔQ is calculated by recording Q1 (evaporation amount including the valve) and Q2 (evaporation amount only in the pipeline). Combined with the latent heat of liquid nitrogen vaporization to convert the heat leakage value, the inherent heat leakage of the test system (such as heat leakage of the pipeline and storage tank itself) and constant errors caused by environmental factors can be effectively eliminated, and the net heat leakage characteristics of the valve under test can be directly quantified. With the help of control variables such as liquid nitrogen level control by liquid level sensor and uniform vacuum conditions, the strict consistency of the comparative test conditions is ensured, so that the heat leakage assessment is upgraded from qualitative description to precise quantification, realizing the scientific measurement of the heat leakage performance of cryogenic valves. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the low-temperature valve heat leakage test equipment in the embodiments of this application; Figure 2 yes Figure 1 A-direction view; Figure 3 This is a schematic diagram of the low-temperature valve heat leakage test equipment in the embodiments of this application.

[0033] Explanation of reference numerals in the attached figures: 100. Valve under test; 1. Dual-chamber container; 11. Test chamber; 12. Storage tank chamber; 2. Liquid nitrogen storage tank; 21. Vent pipe; 22. Liquid inlet pipe; 23. Test gas inlet pipe; 24. Test gas outlet pipe; 3. Evaporation measuring device; 31. Gas collection mechanism; 32. Heater; 33. Flow meter; 34. Molecular sieve desiccant; 4. Vacuum generator; 5. Support column; 6. Insulation material; 7. Connecting pipe; 8. Liquid level sensor. Detailed Implementation

[0034] The following will be combined with the appendix Figure 1-3 The technical solutions in the embodiments of this application are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] This application discloses a cryogenic valve heat leakage testing device and method. (Refer to...) Figure 1 The cryogenic valve leakage testing equipment includes a dual-chamber container 1, which contains an isolated test chamber 11 and a storage tank chamber 12. The test chamber 11 is used to place the valve 100 under test or a replacement pipe, while the storage tank chamber 12 contains a liquid nitrogen storage tank 2. The liquid nitrogen storage tank 2 is covered with an insulation layer to reduce heat loss. A hollow load-bearing column 5 is located on the bottom wall of the storage tank chamber 12. In this embodiment, both ends of the load-bearing column 5 are open to reduce the heat conduction path of the solid material. The load-bearing column 5 is filled with insulation material 6. The liquid nitrogen storage tank 2 is installed on the load-bearing column 5 to reduce heat exchange between the liquid nitrogen storage tank 2 and the inner wall of the storage tank chamber 12. Specifically, both the inner bottom wall of the storage tank chamber 12 and the outer bottom wall of the liquid nitrogen storage tank 2 are equipped with insertion pipes 7. The insertion pipes 7 are fitted onto the load-bearing column 5, and the fitting structure enables rapid positioning and installation of the liquid nitrogen storage tank 2.

[0036] The liquid nitrogen storage tank 2 is connected to a vent pipe 21 and an inlet pipe 22 extending out of the storage tank chamber 12. Both the vent pipe 21 and the inlet pipe 22 include a pipe body and a valve. Liquid nitrogen can be injected into the liquid nitrogen storage tank 2 through the inlet pipe 22, and the gas inside the liquid nitrogen tank is discharged through the vent pipe 21. Both the vent pipe 21 and the inlet pipe 22 are covered with an insulation layer. (Refer to...) Figure 2 The liquid nitrogen storage tank 2 is equipped with a liquid nitrogen level sensor 8 to detect the liquid nitrogen level and provide real-time feedback on the liquid nitrogen level.

[0037] Reference Figure 1 The liquid nitrogen storage tank 2 is connected to a test air inlet pipe 23. The end of the test air inlet pipe 23 away from the liquid nitrogen storage tank 2 passes through the cavity wall of the test chamber 11 and is located inside the test chamber 11, for connection with the valve 100 to be tested or a replacement pipe.

[0038] Reference Figure 3 The evaporation measuring device 3 is connected to the test vent pipe 24, which is located in the test chamber 11 and is used to connect to the valve 100 to be tested or a replacement pipe. The evaporation measuring device 3 is connected to the liquid nitrogen storage tank 2 through the vent pipe 21 and is used to measure the amount of liquid nitrogen evaporation.

[0039] The evaporation measuring device 3 includes a gas collection mechanism 31 and a heater 32. The gas collection mechanism 31 and the heater 32 are connected to the test chamber 11 via an outlet pipe, on which a flow meter 33 is connected. Specifically, the flow meter 33 is a high-precision mass flow meter with a range of 0.1-200 L / min and an error ≤ ±1%FS. The evaporated liquid nitrogen is heated by the heater 32 to restore it to room temperature, facilitating monitoring by the flow meter 33.

[0040] Vacuum generator 4 is connected to test chamber 11 and storage tank chamber 12 via vacuum pipes, and independently controls the vacuum level of test chamber 11 and storage tank chamber 12. Vacuum generator 4 uses a molecular pump to evacuate storage tank chamber 12 to a vacuum level below 0.01 Pa, reducing thermal radiation interference. (Refer to...) Figure 1 The storage tank chamber 12 is equipped with molecular sieve desiccant 34 to maintain the vacuum level within the storage tank chamber 12 at the standard. The vacuum level of the test chamber 11 can be adjusted within the range of 0.01-100 Pa to simulate different working conditions, such as heat leakage of valves under a vacuum of 0.01 Pa or heat leakage of valves after insulation.

[0041] The test inlet pipe 23 and test outlet pipe 24 are equipped with detachable interfaces, which can be detachably connected to the valve under test 100 and the replacement pipe to adapt to valves of different sizes.

[0042] All pipes in the testing equipment are made of stainless steel. The liquid nitrogen storage tank 2 and all other pipes except the vacuum tube are covered with an insulation layer. The heat leakage of the pipeline is ≤0.1W / m². The insulation properties of the insulation layer significantly reduce the transfer of heat from the external environment to the liquid nitrogen storage tank 2 and the pipelines transporting the cryogenic medium. In this example, the insulation layer includes aluminum foil and / or fiberglass paper. The insulation layer thickness is 15-25mm, and the insulation layer density is 25-35 layers / cm. This provides sufficient stacking space to extend the heat transfer path and enhance the barrier effect against heat radiation and heat conduction.

[0043] This application embodiment also provides a method for testing the thermal leakage of a low-temperature valve, using the aforementioned low-temperature valve thermal leakage testing equipment, including the following steps: Install the valve to be tested 100 in the test chamber 11, and use the vacuum generator 4 to evacuate the test chamber 11 and the storage tank chamber 12 to the standard requirements. Liquid nitrogen is injected into liquid nitrogen storage tank 2, the liquid level is controlled to the height of the valve seat of valve 100 to be tested, the vent pipe 21 is closed, and the evaporation amount Q1 after stabilization is recorded using evaporation measuring device 3; Remove the valve 100 to be tested and replace it with a replacement pipe. Use the vacuum generator 4 to evacuate the test chamber 11 to the standard requirements. Inject liquid nitrogen into liquid nitrogen storage tank 2 to fill the replacement pipe, close vent pipe 21, and use evaporation measuring device 3 to record the evaporation amount Q2 after stabilization; Heat loss calculation: ΔQ=Q1-Q2, combined with the latent heat of liquid nitrogen vaporization to calculate the actual heat loss value. This conversion method is existing technology and will not be elaborated in detail.

[0044] By isolating the test chamber 11 from the storage tank chamber 12, the storage tank chamber 12 is kept under vacuum to eliminate external thermal interference. During testing, liquid nitrogen is injected into the liquid nitrogen storage tank 2 and flows through the valve under test or a substitute hose via a pipeline. The valve's heat leakage is accurately calculated by comparing the two evaporation rates (Q1 and Q2). Existing heat leakage testing devices do not consider the heat leakage of the device itself and are subject to significant environmental interference. This application tests the valve's heat leakage under low-temperature conditions and then calculates the valve's heat leakage, thereby more accurately evaluating the valve's performance. It is suitable for evaluating the performance of valves used in cryogenic media such as liquid nitrogen and liquid hydrogen.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A low-temperature valve heat leakage testing device, characterized in that, include: A dual-chamber container (1) has an isolated test chamber (11) and a storage tank chamber (12) inside. The test chamber (11) is used to place the valve (100) to be tested or a replacement pipe. A liquid nitrogen storage tank (2) is located inside the storage tank chamber (12). The liquid nitrogen storage tank (2) is connected to an vent pipe (21) and an inlet pipe (22) that extend out of the storage tank chamber (12), as well as a test air inlet pipe (23) for connecting to the valve to be tested (100) or a replacement pipe. An evaporation measuring device (3) is connected to a test outlet pipe (24) and the liquid nitrogen storage tank (2). The test outlet pipe (24) is located in the test chamber (11) and is used to connect to the valve to be tested (100) or a replacement pipe. The evaporation measuring device (3) is used to measure the amount of liquid nitrogen evaporation. The vacuum generating device (4) is connected to the test chamber (11) and the storage tank chamber (12) respectively through a vacuum tube, and independently controls the vacuum level of the test chamber (11) and the storage tank chamber (12).

2. The low-temperature valve heat leakage testing equipment according to claim 1, characterized in that, The evaporation measuring device (3) includes a gas collection mechanism (31) and a heater (32). The gas collection mechanism (31) and the heater (32) are connected to the test chamber (11) through an outlet pipe, and a flow meter (33) is connected to the outlet pipe.

3. The low-temperature valve heat leakage testing equipment according to claim 1, characterized in that, The storage tank chamber (12) is maintained at a vacuum level below 0.01 Pa; and / or, The storage tank chamber (12) is equipped with a molecular sieve desiccant (34).

4. The low-temperature valve heat leakage testing equipment according to claim 1, characterized in that, The bottom wall of the storage tank chamber (12) is provided with a hollow load-bearing column (5), and the load-bearing column (5) is filled with heat-insulating material (6). The liquid nitrogen storage tank (2) is installed on the load-bearing column (5).

5. The low-temperature valve heat leakage testing equipment according to claim 4, characterized in that, The liquid nitrogen storage tank (2) has a plug pipe (7) on its outer bottom wall, and the plug pipe (7) is sleeved on the load-bearing column (5).

6. The low-temperature valve heat leakage testing equipment according to claim 1, characterized in that, The liquid nitrogen storage tank (2) and all other pipes except the vacuum tube are covered with an insulation layer.

7. The low-temperature valve heat leakage testing equipment according to claim 6, characterized in that, The insulation layer comprises aluminum foil and / or fiberglass paper.

8. The low-temperature valve heat leakage testing equipment according to claim 7, characterized in that, The insulation layer has a thickness of 15-25 mm; and / or, The density of the insulation layer is 25-35 layers / cm.

9. The low-temperature valve heat leakage testing equipment according to claim 1, characterized in that, The liquid nitrogen storage tank (2) is equipped with a liquid nitrogen level sensor (8) for detecting the liquid nitrogen level.

10. A method for testing the thermal leakage of a low-temperature valve, applied to the low-temperature valve thermal leakage testing equipment described in any one of claims 1 to 9, characterized in that, Includes the following steps: The valve to be tested (100) is installed in the test chamber (11), and the test chamber (11) and the storage tank chamber (12) are evacuated to the standard requirements using the vacuum generator (4); Liquid nitrogen is injected into the liquid nitrogen storage tank (2), the liquid level is controlled to the height of the valve seat of the valve to be tested (100), the vent pipe (21) is closed, and the evaporation amount Q1 after stabilization is recorded using the evaporation measuring device (3); Remove the valve (100) to be tested and replace it with the replacement pipe. Use the vacuum generator (4) to evacuate the test chamber (11) to the standard requirements. Liquid nitrogen is injected into the liquid nitrogen storage tank (2) to fill the replacement pipe, the vent pipe (21) is closed, and the evaporation amount Q2 after stabilization is recorded using the evaporation measuring device (3). Heat loss calculation: ΔQ=Q1-Q2, and the actual heat loss value is calculated by combining the latent heat of liquid nitrogen vaporization.

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