Material gas permeation performance testing device and method under low temperature working condition

Abstract

The application relates to a device and method for testing the gas permeability of materials under low-temperature working conditions, which comprises a vacuum insulation cabin, a clamping unit arranged in the vacuum insulation cabin, the clamping unit comprising an upper cavity, a support and heat conduction integrated component and a lower cavity, a permeation part being arranged on the support and heat conduction integrated component, the upper side of the support and heat conduction integrated component supporting a measured sample, and the lower side of the support and heat conduction integrated component being communicated with the inlet of the lower cavity; a sealing gasket made of a shape memory alloy material being arranged between the outlet of the upper cavity and the measured sample; the upper cavity and the lower cavity being respectively connected with a vacuum pump; the lower cavity being connected with a permeation signal detection unit I; a gas supply unit supplying test gas and inert gas to the upper cavity, and comprising a pressure regulating and monitoring device; a permeation signal detection unit II obtaining quantum state disturbance signals related to the adsorption and desorption of the test gas by the measured sample; and a low-temperature control unit controlling the measured sample to be stably set at a set temperature through a temperature adjusting module. The application can stably and reliably characterize the gas permeability of materials under low-temperature and high-pressure working conditions.

Description

Technical Field

[0001] This invention relates to the field of gas permeation testing technology, and in particular to a device and method for testing the gas permeation performance of materials under low-temperature conditions. Background Technology

[0002] With the rapid development of hydrogen energy in transportation, energy storage, and energy conversion, the demand for hydrogen storage and transportation under low temperature and high pressure conditions is increasing. Materials used in hydrogen storage cylinders and pipelines, especially polymer liners and carbon fiber composites, typically bear external structural stress, impact loads from cryogenic fluid sloshing, and temperature stress loads caused by the low-temperature environment during service. Their gas permeability under low temperature and high pressure directly affects the safety and reliability of the system.

[0003] Existing gas permeation testing devices are mostly designed for ambient temperature or medium pressure conditions, making it difficult to simultaneously meet the coupled testing requirements of cryogenic and high-pressure conditions. On the one hand, traditional permeation testing devices lack sufficient sealing reliability under cryogenic conditions, making them prone to parasitic leaks and hindering testing under cryogenic conditions. On the other hand, most devices can only load gas within a limited pressure range, failing to cover the actual operating conditions of high-pressure hydrogen storage. Furthermore, gas loading methods are diverse in cryogenic high-pressure permeation performance characterization systems: high-pressure gas cylinders can be used directly in the low-to-medium pressure range, while pressure boosting equipment is typically required at higher pressures. However, few existing technologies can provide a system compatible with these different pressure loading conditions on the same platform and establish a standardized, repeatable testing methodology. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a device and method for testing the gas permeability of materials under low-temperature conditions, solving the technical problem that existing technologies cannot operate stably under low-temperature and high-pressure coupled conditions and can adapt to in-situ gas permeability simulation under different pressure loading modes.

[0005] The technical solution adopted in this invention is as follows: This invention provides a device for testing the gas permeability of materials under low-temperature conditions, comprising: Vacuum insulation chamber, which is used to provide a low-heat-leakage vacuum insulation environment; The clamping unit, located within the vacuum insulation chamber, comprises an upper chamber, an integrated support and heat conduction component, and a lower chamber connected sequentially from top to bottom. The integrated support and heat conduction component has a permeation section, the upper side of which supports the sample to be tested, and the lower side of which communicates with the inlet of the lower chamber. A sealing gasket made of shape memory alloy material is provided between the outlet of the upper chamber and the sample to be tested. The upper and lower chambers are connected only through the sample to be tested and the permeation section. The upper and lower chambers are respectively connected to a vacuum pump. The permeation signal detection unit I is a gas permeation flux detection unit based on a helium mass spectrometer. It is connected to the lower chamber through a first shut-off valve to quantitatively detect the gas that permeates through the sample and the permeation section into the lower chamber. The gas supply unit includes high-pressure gas cylinders that supply test gas and inert gas respectively. The outlet of the cylinder is connected to the upper cavity through a high-pressure pipeline. The high-pressure pipeline is equipped with a pressure regulating and monitoring device for controlling the pressure of the supplied gas. A venting branch is also connected to the high-pressure pipeline. Permeation signal detection unit II is used to collect signals from the test sample or permeation section to obtain quantum state perturbation signals generated by the test sample during the adsorption and desorption of the test gas. The low-temperature control unit includes a pulse tube refrigerator used as a cold source, the cold end of which is connected to an integrated support and heat conduction component, and controls the sample under test to be stabilized at a set temperature through a temperature regulation module.

[0006] The preferred technical solution is: The structure of the permeation signal detection unit II includes a detector based on a superconducting quantum interference device, which is connected to the integrated support and heat conduction component through a high thermal conductivity connection component to form a low-temperature working environment; The detector is also connected to the sample or permeation section under test via a physical coupling component, and acquires signals based on the material’s response to gas adsorption and desorption. The detector is sequentially connected to a low-noise signal amplification unit, a data interface, and a data processing unit for the calculation and analysis of subsequent permeability performance parameters.

[0007] The physical coupling component includes a superconducting flux converter.

[0008] The temperature regulation module includes a power regulator, a PID temperature controller, and a temperature sensor. The temperature sensor is mounted on the integrated support and heat conduction component. The PID temperature controller receives the signal from the temperature sensor and outputs a control signal to the power regulator, which dynamically adjusts the input power of the pulse tube refrigerator to stabilize the temperature of the sample under test at the set temperature.

[0009] The pressure regulation and monitoring device includes a second shut-off valve, a first filter, a pressure reducing valve, a booster pump, a back pressure valve, a pressure sensor, and a first pressure gauge arranged in sequence. It also includes an overpressure protection controller and an emergency shut-off valve located downstream of the back pressure valve. The overpressure protection controller is connected to the emergency shut-off valve and the pressure sensor, respectively.

[0010] The venting branch includes a pressure relief valve, a second filter, and a venting pipeline connected in sequence; the inlet end of the pressure relief valve is connected to the upper cavity.

[0011] The integrated support and heat conduction component is made of metal, and the permeable part is a high-strength mesh structure.

[0012] The vacuum insulation chamber is evacuated by a turbomolecular pump, and a second pressure gauge is installed on the connecting pipeline between the vacuum insulation chamber and the turbomolecular pump.

[0013] The present invention also provides a testing method for the gas permeability testing device for materials under low-temperature conditions, comprising: The sample to be tested is clamped in the clamping unit; Inert gas and test gas are supplied sequentially through the gas supply unit to purge the high-pressure pipeline and vent it through the vent branch; the lower chamber and upper chamber are evacuated sequentially through the vacuum pump until the set state is reached; the vacuum insulation chamber is then evacuated. Activate the low-temperature control unit to stabilize the sample under test at the set temperature; Tests were conducted under either the first or second operating condition, including: The test gas is controlled by the pressure regulation and monitoring device to be filled into the upper chamber at the first working condition pressure or the second working condition pressure, so that the pressure in the upper chamber reaches the set value and remains stable. Driven by a pressure gradient, the test gas permeates from the upper chamber through the sample under test and the permeation section to the lower chamber. The lower chamber is kept connected to the vacuum pump and the permeation signal detection unit I. The permeated gas is detected by a helium mass spectrometer leak detector. Depending on the testing requirements, select whether to activate the permeation signal detection unit II, so that the detector can synchronously collect the quantum state perturbation signal generated by the sample under test during the adsorption and desorption of the test gas under low temperature conditions.

[0014] The preferred technical solution is: The pressure under the first working condition is no greater than 20 MPa, and the pressure under the second working condition is greater than 20 MPa.

[0015] The technical solution of the present invention can achieve at least some of the following beneficial effects: This invention's testing device integrates high-vacuum insulation, pulsed cooling cryogenic control, and multi-mode gas supply units, constructing a stable in-situ testing platform that simulates the extreme environments of actual hydrogen storage and transportation. By simultaneously introducing cryogenic and high-pressure gas conditions within a controlled environment, independent and precise control and reliable coupling of cryogenic and high-pressure conditions are achieved. This allows for long-term stable operation across a wide temperature range (especially deep cryogenic) and a wide pressure range (from medium to ultra-high pressure), placing the test material in a service environment closely resembling actual hydrogen storage and transportation conditions during testing. This enables precise characterization of the material's gas permeation behavior and accurate evaluation of its permeation performance. It is particularly suitable for in-situ characterization of gas permeation behavior in composite materials, polymer linings, and their interfacial structures under cryogenic and high-pressure coupled conditions.

[0016] Addressing the technical bottleneck of traditional sealing materials' susceptibility to failure due to cold contraction at deep temperatures, this invention innovatively employs shape memory alloy gaskets. These gaskets utilize their unique temperature-shape memory effect to generate additional recovery stress at low temperatures, dynamically compensating for sealing pressure losses caused by differences in the thermal expansion coefficients of various components, thus achieving long-term reliable and excellent sealing performance.

[0017] This invention integrates two modes—direct loading from high-pressure cylinders and loading via a booster pump—into a single system. Depending on testing requirements, a first operating pressure suitable for medium to high pressure (e.g., ≤20MPa) or a second operating pressure suitable for ultra-high pressure (e.g., >20MPa) can be flexibly selected without replacing the core components. Simultaneously, the device is equipped with an active protection unit including an overpressure protection controller and a safety emergency shut-off valve, as well as independent pressure relief and discharge pipelines, forming a multi-layered safety protection system to ensure the safety and reliability of the high-pressure testing process.

[0018] This invention enhances the monitoring of gas permeation processes under extremely low permeation flux conditions by introducing a highly sensitive gas permeation signal detection unit II based on a superconducting quantum interference device into the permeation detection apparatus. By using permeation signal detection unit II in parallel with permeation signal detection unit I, a multi-physical quantity synergistic gas permeation detection system is constructed, overcoming the sensitivity limitations of traditional flow rate or pressure change-based detection methods. This significantly expands the sensitivity range and applicable scenarios for in-situ characterization of material permeation performance under low temperature and high pressure conditions.

[0019] This invention achieves rapid temperature attainment and high-precision stable control of samples through a closed-loop temperature control system consisting of a high-precision temperature sensor, a PID controller, and a power regulator.

[0020] Other features and advantages of the invention will be set forth in the following description or may be learned by practicing the invention. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the device according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the internal structure of the vacuum insulation chamber of the device in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached diagram: 1. Turbomolecular pump; 2. Second pressure gauge; 3. Vacuum insulation chamber; 4. Sample under test; 5. Upper chamber; 6. Lower chamber; 7. High-pressure gas cylinder; 8. Second shut-off valve; 9. First filter; 10. Pressure reducing valve; 11. Booster pump; 12. Back pressure valve; 13. Pressure sensor; 14. First pressure gauge; 15. Vacuum pump; 16. Permeation signal detection unit I; 17. Pulse tube refrigerator; 18. Temperature sensor; 19. PID temperature controller; 20. Power regulator; 21. Upper flange; 22. Lower flange; 23. Sealing gasket; 24. Integrated support and heat conduction component; 25. Pressure relief valve; 26. Second filter; 27. Discharge pipeline; 28. Overpressure protection controller; 29. ​​Emergency shut-off valve; 30. Third shut-off valve; 31. Fourth shut-off valve; 32. Second pressure gauge; 33. First shut-off valve; 34. Data processing unit; 35. Detector; 36. High thermal conductivity connection component; 37. Physical coupling component; 38. Low noise signal amplification unit; 39. Data interface; 241. Permeation section. Detailed Implementation

[0024] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0025] Example 1

[0026] See Figure 1 and Figure 2 The material gas permeability testing device under low-temperature conditions in this embodiment includes: Vacuum insulation chamber 3, which is used to provide a low heat leakage vacuum insulation environment; The clamping unit, located within the vacuum insulation chamber 3, comprises, from top to bottom, an upper cavity 5, an integrated support and heat conduction component 24, and a lower cavity 6. The integrated support and heat conduction component 24 has a permeation section 241, the upper side of which supports the sample 4 to be tested, and the lower side of which is connected to the inlet of the lower cavity 6. A sealing gasket 23, made of shape memory alloy material, is provided between the outlet of the upper cavity 5 and the sample 4 to be tested. The upper cavity 5 and the lower cavity 6 are connected only through the sample 4 to be tested and the permeation section 241. The upper cavity 5 and the lower cavity 6 are respectively connected to the vacuum pump 15. The permeation signal detection unit I 16 is a gas permeation flux detection unit based on a helium mass spectrometer. It is connected to the lower chamber 6 through the first shut-off valve 33 to quantitatively detect the gas that permeates through the sample 4 and the permeation section 241 into the lower chamber 6. The gas supply unit includes two high-pressure gas cylinders 7 for supplying test gas and inert gas respectively. The outlets of the two high-pressure gas cylinders 7 are connected to the upper chamber 5 through high-pressure pipelines. The high-pressure pipelines are equipped with pressure regulating and monitoring devices for controlling the pressure of the supplied gas. The high-pressure pipelines are also connected to a venting branch. The permeation signal detection unit II is used to collect signals from the test sample 4 or the permeation section 241 to obtain the quantum state perturbation signal generated by the test sample 4 during the adsorption and desorption of the test gas. The low-temperature control unit includes a pulse tube refrigerator 17 used as a cold source, the cold end of which is connected to a support and heat conduction integrated component 24, and controls the sample 4 to be tested to be stabilized at a set temperature through a temperature regulation module.

[0027] The test apparatus in this embodiment integrates high-vacuum insulation, pulsed cooling cryogenic control, and multi-mode gas supply units, constructing a test platform capable of stably simulating the extreme environments of actual hydrogen storage and transportation. It can operate stably for extended periods under a wide temperature range (especially deep cryogenic temperatures) and a wide pressure range (from medium pressure to ultra-high pressure), achieving independent and precise control and reliable coupling of cryogenic and high-pressure conditions.

[0028] During testing, the upper chamber 5 is used to load the test gas, and the lower chamber 6 is used to collect and detect the permeated gas that has passed through the sample under test. Apart from the permeation section 241 supporting the sample under test and the sample 4 under test, there are no other gas communication paths between the upper and lower chambers, thus ensuring the reliability of the permeation test results. Specifically, the upper chamber 5 is provided with an upper flange 21, and the lower chamber 6 is provided with a lower flange 22. The upper flange 21 and lower flange 22 are connected to clamp the integrated support and heat conduction component 24 and the sample 4 placed on the permeation section 241 between the upper and lower chambers. The integrated support and heat conduction component 24 is preferably made of a thermally conductive metal, serving as a heat conduction channel between the cryogenic control unit and the sample 4 under test, transferring the cold energy generated by the cryogenic control unit to the sample 4 under test. The permeation section 241 is preferably a high-strength mesh structure, which serves two purposes: firstly, to provide mechanical support for the sample 4 under test when there is a pressure difference between the upper and lower chambers, and secondly, to form a permeation channel.

[0029] To ensure airtightness, a sealing gasket 23 is installed between the tested sample 4 and the outlet of the upper cavity 5. This gasket is made of shape memory alloy to maintain reliable airtight sealing performance under low-temperature conditions. Specifically, during temperature changes, the sealing gasket 23 generates additional recovery stress, applying continuous compression to the sealing interface under low-temperature conditions. This compensates for changes in sealing force caused by differences in component thermal shrinkage, ensuring the stability of the sealing state during testing.

[0030] Specifically, the upper chamber 5 is connected to the vacuum pump 15 via the third shut-off valve 30, and the lower chamber 6 is connected to the vacuum pump 15 via the fourth shut-off valve 31. A second pressure gauge 32 is installed on the connecting pipeline for pressure monitoring.

[0031] Specifically, the vacuum chamber 3 is evacuated using a turbomolecular pump 1 to create a stable vacuum insulation environment during testing, thereby reducing the impact of the external environment on the internal low-temperature testing conditions. A second pressure gauge 2 is installed on the connecting pipeline between the vacuum chamber 3 and the turbomolecular pump 1 to monitor the vacuum status inside the chamber in real time.

[0032] The gas supply unit is used to supply inert gas (e.g., He) and test gas (e.g., H2) to the upper chamber 5 and to achieve stable loading under different pressure conditions. The pressure regulation and monitoring device includes a second shut-off valve 8, a first filter 9, a pressure reducing valve 10, a booster pump 11, a back pressure valve 12, a pressure sensor 13, and a first pressure gauge 14, arranged sequentially. When the required test pressure is within the range that the high-pressure gas cylinder 7 can directly supply, the gas is regulated by the pressure reducing valve 10 and then the pressure in the upper chamber 5 is precisely controlled and stably maintained by the back pressure valve 12. When the required test pressure is higher than the direct gas supply capacity of the high-pressure gas cylinder 7, the depressurized test gas enters the booster pump 11 for further pressurization, and is then regulated by the back pressure valve 12 before being loaded into the upper chamber 5. The pressure in the upper chamber 5 is monitored in real time by the pressure sensor 13 and the first pressure gauge 14.

[0033] Furthermore, the gas supply unit also includes an overpressure protection controller 28 and an emergency shut-off valve 29 located downstream of the back pressure valve 12. The overpressure protection controller 28 is connected to the emergency shut-off valve 29 and the pressure sensor 13, respectively. When the pressure in the upper chamber 5 exceeds the set safety threshold, the overpressure protection controller 28 will trigger the emergency shut-off valve 29 located downstream of the back pressure valve 12 to operate, thereby cutting off the gas supply and ensuring the safety of system operation.

[0034] Furthermore, after the test, the upper chamber 5 is depressurized in a controlled manner through the venting branch, and the residual gas is filtered and discharged. The venting branch includes a pressure relief valve 25, a second filter 26, and a venting pipe 27 connected in sequence, with the inlet end of the pressure relief valve 25 connected to the upper chamber 5.

[0035] To achieve precise control of the low-temperature environment of the sample 4 under test, this embodiment includes a low-temperature control unit. Specifically, the cold head of the pulse tube refrigerator 17 is connected to the integrated support and heat conduction component 24 via a heat transfer component, achieving heat conduction with the sample 4 under test. Preferably, the temperature regulation module includes a power regulator 20, a PID temperature controller 19, and a temperature sensor 18. The temperature sensor 18 is preferably a platinum resistance temperature sensor, mounted on the integrated support and heat conduction component 24 to collect the temperature signal of the sample 4 under test in real time. The PID temperature controller 19 receives the signal from the temperature sensor 18 and compares it with the set temperature value. Through PID calculations (proportional, integral, and derivative operations), it outputs a control signal to the power regulator 20, which dynamically adjusts the input power of the pulse tube refrigerator 17, thereby continuously regulating the cooling capacity in real time, ensuring that the temperature of the sample 4 under test remains stable at the set temperature during the testing process.

[0036] Specifically, the permeation signal detection unit I 16 employs a helium mass spectrometer. During the test, a trace amount of gas that permeates through the sample 4 into the lower chamber 6 is introduced into the helium mass spectrometer for detection by the vacuum pump 15. The permeation signal output by the helium mass spectrometer, along with the synchronously acquired pressure and temperature signals, is transmitted to the data processing unit 34. The data processing unit 34 records, analyzes, and processes the test data to obtain the gas permeation performance parameters of the sample 4 under low-temperature and high-pressure conditions.

[0037] The permeation signal detection unit II in this embodiment is used to detect in situ changes in weak physical quantities related to the gas permeation process under low temperature conditions. These changes include, but are not limited to, quantum state perturbation signals related to the adsorption and desorption behavior of gas molecules. This enables highly sensitive monitoring of the permeation process under extremely low permeation flux conditions without relying on a single gas flow rate or pressure change detection method.

[0038] By using the permeation signal detection unit II and the permeation signal detection unit I 16 in parallel, this embodiment constructs a gas permeation detection system with multi-physical quantity synergy, which can significantly expand the sensitivity range and applicable scenarios of in-situ characterization of material permeation performance under low temperature and high pressure conditions.

[0039] As a preferred embodiment, the structure of the permeation signal detection unit II includes a detector 35 based on a superconducting quantum interference device, which is connected to a support and heat conduction integrated component 24 via a high thermal conductivity connection component 36 to form a low-temperature working environment; the detector 35 is also connected to the sample 4 or the permeation section 241 under test via a physical coupling component 37, and collects signals based on the material's response to gas adsorption and desorption; the detector 35 is sequentially connected to a low-noise signal amplification unit 38, a data interface 39, and a data processing unit 34 for subsequent calculation and analysis of permeation performance parameters.

[0040] The detector 35 is preferably a superconducting quantum interference device; the physical coupling component 37 is preferably a superconducting flux converter, such as NbTi wire. The high thermal conductivity connecting component 36 is preferably made of a high thermal conductivity metal, such as copper strip. The high thermal conductivity connecting component 36 is used to improve the heat transfer effect between the detector 35 and the integrated support and heat conduction component 24.

[0041] Example 2

[0042] This embodiment provides a testing method for a material gas permeation performance testing device under low-temperature conditions according to Embodiment 1. During the test, the test condition is selected based on the required test pressure range, using only the high-pressure gas cylinder 7 for gas loading or combining it with the booster pump 11 for pressurization. After gas purging, low-temperature stabilization, and pressure loading are completed, the permeated gas in the lower chamber 6 is continuously monitored using helium mass spectrometry and a high-sensitivity permeation signal detection unit II. After the test is completed, the system is depressurized in a controlled manner through the venting branch and gradually warmed up to complete the entire test process.

[0043] The testing method specifically includes the following steps: S1. The sample 4 to be tested is clamped in the clamping unit.

[0044] Specifically, ensure that the surface of the sample 4 under test is flat and the stress is uniform, and that a reliable seal is achieved through the sealing gasket 23. Inspect all high-pressure connections and sealing structures to ensure that the overall airtightness of the device meets the test requirements.

[0045] S2. Inert gas and test gas are supplied sequentially through the gas supply unit to purge the high-pressure pipeline and vent through the venting branch to reduce the residual amount of non-test gas in the device.

[0046] Specifically, with the booster pump 11 closed, inert gas is introduced through the high-pressure gas cylinder 7 storing inert gas to purge the upper chamber 5 pipeline and then vent it through the vent branch; then the high-pressure gas cylinder 7 storing inert gas is closed, and test gas is introduced through the high-pressure gas cylinder 7 storing test gas to purge and vent the upper chamber 5 pipeline again along the same path.

[0047] S3. Open the fourth shut-off valve 31, start the vacuum pump 15, evacuate the lower chamber 6, and maintain the evacuation state until the vacuum level stabilizes. Then open the third shut-off valve 30 and start the vacuum pump 15 to evacuate the upper chamber 5 and its related pipelines, so that the upper chamber 5 and the lower chamber 6 enter a synchronous vacuum state until the set state is reached. After the vacuum degree of the upper chamber 5 and the lower chamber 6 reaches the set state, close the third shut-off valve 30 and the fourth shut-off valve 31 respectively to stop the vacuuming operation. S4. Evacuate the vacuum insulation chamber 3.

[0048] Specifically, the turbomolecular pump 1 is started to evacuate the vacuum insulation chamber 3, so that a stable vacuum insulation environment is formed inside the chamber.

[0049] S5. Activate the low temperature control unit to stabilize the tested sample 4 at the set temperature.

[0050] S6. Conduct tests under either the first or second operating condition, including: The test gas is controlled by the pressure regulation and monitoring device to be charged into the upper chamber 5 at the first working condition pressure (medium and high pressure) or the second working condition pressure (ultra-high pressure). The pressure of the upper chamber 5 is monitored in real time by the pressure sensor 13 and the first pressure gauge 14 to make the pressure of the upper chamber 5 reach the set value and remain stable. Driven by a pressure gradient, the test gas permeates from the upper chamber 5 through the sample 4 and the permeation section 241 to the lower chamber 6. The lower chamber 6 is kept connected to the vacuum pump 15 and the permeation signal detection unit I 16. The permeated gas is detected by a helium mass spectrometer leak detector. Based on the testing requirements, select whether to activate the permeation signal detection unit II, so that the detector 35 can synchronously collect the quantum state perturbation signal generated by the test sample 4 during the adsorption and desorption of the test gas under low temperature conditions.

[0051] The pressure under the first working condition is no greater than 20 MPa, and the pressure under the second working condition is greater than 20 MPa.

[0052] Specifically, when the test pressure does not exceed the pressure range that the high-pressure gas cylinder 7 can directly provide, the first operating condition pressure test is adopted. With the booster pump 11 closed, the high-pressure gas cylinder 7 and its corresponding second shut-off valve 8 are opened, allowing the test gas to enter the upper chamber 5 sequentially through the first filter 9 and the pressure reducing valve 10. By adjusting the pressure reducing valve 10 and the back pressure valve 12, the gas pressure in the upper chamber 5 is slowly increased to the set test pressure.

[0053] During the test, the pressure in the upper chamber 5 is monitored in real time by pressure sensor 13 and pressure gauge 14, and the pressure is dynamically stabilized by back pressure valve 12. After the high pressure and low temperature test conditions in the upper chamber 5 reach a stable state, the detection unit is activated to monitor the changes in weak physical quantities related to the gas permeation process in situ: while keeping the lower chamber 6 connected to the vacuum pump 15 and the permeation signal detection unit I 16, the permeated gas is detected; at the same time, according to the test requirements, the parallel permeation signal detection unit II is activated, so that the detector 35 based on the superconducting quantum interference device can synchronously collect the quantum state perturbation signal generated during the gas adsorption and desorption process under low temperature conditions. The detection signal is amplified by the signal amplification unit 38 and transmitted to the data processing unit 34 through the data interface 39 for subsequent calculation and analysis of permeation performance parameters, completing the gas permeation test under the first working pressure.

[0054] Specifically, when the required test pressure exceeds the pressure range directly provided by the high-pressure cylinder 7, the second operating condition pressure test is adopted. The high-pressure cylinder 7 and its corresponding second shut-off valve 8 are opened, and the booster pump 11 is started. The test gas passes sequentially through the first filter 9 and the pressure reducing valve 10 into the booster pump 11. The output pressure of the booster pump is adjusted by the back pressure valve 12 on its outlet side, gradually increasing the test gas pressure to the set ultra-high pressure test pressure and loading it into the upper chamber 5. During the pressurization process, the pressure in the upper chamber 5 is monitored in real time by the pressure sensor 13 and the pressure gauge 14. After the high-pressure and low-temperature test conditions in the upper chamber 5 have both reached a stable state, the detection unit is activated to monitor the changes in subtle physical quantities related to the gas permeation process in situ. While maintaining the connection between the lower chamber 6 and the vacuum pump 15 and the permeation signal detection unit I 16, the permeated gas is detected. At the same time, according to the test requirements, the parallel permeation signal detection unit II is activated, so that the detector 35 based on the superconducting quantum interference device can synchronously collect the quantum state disturbance signals generated during the gas adsorption and desorption process under low-temperature conditions. The detection signal is amplified by the signal amplification unit 38 and transmitted to the data processing unit 34 through the data interface 39 for subsequent calculation and analysis of permeation performance parameters, thus completing the gas permeation test under the second working pressure.

[0055] Specifically, the two types of signals, namely, the permeation signal detection unit I and the permeation signal detection unit II, can be transmitted to the data processing unit 34 for correlation analysis.

[0056] S7. Depressurize after the test, including: After the test is completed, stop the data acquisition of the penetration signal detection unit II and put it out of the detection working state; Close the high-pressure gas cylinder 7 and booster pump 11 in sequence, open the pressure relief valve 25, and depressurize the residual test gas in the upper chamber 5 in a controlled manner through the second filter 26 and the discharge pipeline 27. Then, inert gas is introduced to purge and empty the upper chamber 5; Turn off the low-temperature control unit and allow the clamping unit to gradually return to room temperature; stop the operation of vacuum pump 15, release the vacuum state of lower chamber 6, open vacuum insulation chamber 3, take out the sample 4 to be tested, and complete the test.

[0057] In summary, this invention provides a testing device and method for in-situ simulating the gas permeation performance of materials under low-temperature and high-pressure coupled conditions. By constructing a stable and controllable low-temperature vacuum environment, a gas loading path with a wide pressure range, and a variety of selectable highly sensitive detection methods, reliable testing and quantitative analysis of material permeation behavior under extremely low permeation flux conditions are achieved.

[0058] It will be understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for testing the gas permeability of materials under low-temperature conditions, characterized in that, include: Vacuum insulation chamber (3), which is used to provide a low heat leakage vacuum insulation environment; The clamping unit, located inside the vacuum insulation chamber (3), includes an upper cavity (5), a support and heat conduction integrated component (24), and a lower cavity (6) connected sequentially from top to bottom. The support and heat conduction integrated component (24) is provided with a permeation part (241), the upper side of which is used to support the sample to be tested (4), and the lower side is connected to the inlet of the lower cavity (6). A sealing gasket (23) is provided between the outlet of the upper cavity (5) and the sample to be tested (4), which is made of shape memory alloy material. The upper cavity (5) and the lower cavity (6) are connected only through the sample to be tested (4) and the permeation part (241). The upper cavity (5) and the lower cavity (6) are respectively connected to the vacuum pump (15). The permeation signal detection unit I (16) is a gas permeation flux detection unit based on a helium mass spectrometer. It is connected to the lower chamber (6) through the first shut-off valve (33) to quantitatively detect the gas that permeates through the sample (4) and the permeation section (241) into the lower chamber (6). The gas supply unit includes a high-pressure gas cylinder (7) that supplies test gas and inert gas respectively. Its outlet is connected to the upper chamber (5) through a high-pressure pipeline. The high-pressure pipeline is equipped with a pressure regulating and monitoring device for controlling the pressure of the supplied gas. The high-pressure pipeline is also connected to a venting branch. The permeation signal detection unit II is used to collect signals from the test sample (4) or the permeation section (241) to obtain the quantum state perturbation signal generated by the test sample (4) during the adsorption and desorption of the test gas; The low-temperature control unit includes a pulse tube refrigerator (17) used as a cold source, the cold end of which is connected to an integrated support and heat conduction component (24), and controls the sample (4) to be tested to be stabilized at a set temperature through a temperature regulation module.

2. The material gas permeability testing device under low-temperature conditions according to claim 1, characterized in that, The structure of the permeation signal detection unit II includes a detector (35) based on a superconducting quantum interference device, which is connected to the integrated support and heat conduction component (24) through a high thermal conductivity connection component (36) to form a low temperature working environment; The detector (35) is also connected to the sample (4) or the permeation section (241) under test via a physical coupling member (37) to collect signals based on the material’s response to gas adsorption and desorption. The detector (35) is connected in sequence to the low-noise signal amplification unit (38), the data interface (39), and the data processing unit (34) for subsequent calculation and analysis of permeability performance parameters.

3. The material gas permeability testing device under low-temperature conditions according to claim 2, characterized in that, The physical coupling component (37) includes a superconducting flux converter.

4. The material gas permeability testing device under low-temperature conditions according to claim 1, characterized in that, The temperature regulation module includes a power regulator (20), a PID temperature controller (19), and a temperature sensor (18). The temperature sensor (18) is mounted on the integrated support and heat conduction component (24). The PID temperature controller (19) receives the signal from the temperature sensor (18) and outputs a control signal to the power regulator (20), which dynamically adjusts the input power of the pulse tube refrigerator (17) to stabilize the temperature of the sample (4) under test at the set temperature.

5. The material gas permeability testing device under low-temperature conditions according to claim 1, characterized in that, The pressure regulation and monitoring device includes a second shut-off valve (8), a first filter (9), a pressure reducing valve (10), a booster pump (11), a back pressure valve (12), a pressure sensor (13), and a first pressure gauge (14) arranged in sequence. It also includes an overpressure protection controller (28) and an emergency shut-off valve (29) located downstream of the back pressure valve (12). The overpressure protection controller (28) is connected to the emergency shut-off valve (29) and the pressure sensor (13), respectively.

6. The material gas permeability testing device under low-temperature conditions according to claim 1, characterized in that, The venting branch includes a pressure relief valve (25), a second filter (26), and a venting pipeline (27) connected in sequence; the inlet end of the pressure relief valve (25) is connected to the upper chamber (5).

7. The material gas permeability testing device under low-temperature conditions according to claim 1, characterized in that, The integrated support and heat conduction component (24) is made of metal, and the permeable part (241) is a high-strength mesh structure.

8. The material gas permeability testing device under low-temperature conditions according to claim 1, characterized in that, The vacuum insulation chamber (3) is evacuated by a turbomolecular pump (1), and a second pressure gauge (2) is provided on the connecting pipe between the vacuum insulation chamber (3) and the turbomolecular pump (1).

9. A test method for a material gas permeability testing device under low-temperature conditions according to any one of claims 1 to 8, characterized in that, include: The sample to be tested (4) is clamped in the clamping unit; Inert gas and test gas are supplied sequentially through the gas supply unit to purge the high-pressure pipeline and vent it through the vent branch; the lower chamber (6) and upper chamber (5) are evacuated sequentially through the vacuum pump (15) until the set state is reached; the vacuum insulation chamber (3) is evacuated. Start the low temperature control unit to stabilize the sample (4) at the set temperature; Tests were conducted under either the first or second operating condition, including: The test gas is controlled by the pressure regulation and monitoring device to be filled into the upper chamber (5) at the first working condition pressure or the second working condition pressure, so that the pressure in the upper chamber (5) reaches the set value and remains stable; Driven by a pressure gradient, the test gas permeates from the upper chamber (5) through the sample (4) and the permeation section (241) to the lower chamber (6), keeping the lower chamber (6) connected to the vacuum pump (15) and the permeation signal detection unit I (16), and detecting the permeated gas using a helium mass spectrometer leak detector. According to the test requirements, select whether to turn on the permeation signal detection unit II so that the detector (35) can synchronously collect the quantum state disturbance signal generated by the test sample (4) during the adsorption and desorption of the test gas under low temperature conditions.

10. The test method according to claim 9, characterized in that, The pressure under the first working condition is no greater than 20 MPa, and the pressure under the second working condition is greater than 20 MPa.

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