Hydrogen flow calibrating device adopting pVTt method

Abstract

The utility model provides a pVTt method hydrogen flow calibrating device which comprises a gas supply pipeline, a pressure regulating module, a heat exchange module, a gas storage pressure stabilizing module, a detected hydrogen module, a measuring module and a gas exhaust pipeline which are sequentially arranged, the measuring module comprises a measuring assembly and a measuring tank, the pressure regulating module, the heat exchange module, the gas storage pressure stabilizing module, the detected hydrogen module and the measuring tank are sequentially communicated in an on-off manner and form a hydrogen detection flow path with the gas supply pipeline and the gas exhaust pipeline; the measuring assembly is used for measuring time for hydrogen to flow into or out of the measuring tank and temperature change and pressure change in the measuring tank, and the detected hydrogen module is used for measuring the flow of hydrogen flowing into the measuring tank; and the pressure regulating module and the detected hydrogen module can be communicated in an on-off manner and form a purging flow path with the gas supply pipeline and the gas exhaust pipeline. According to the technical scheme provided by the utility model, the temperature and pressure verification condition range and verification precision of the pVTt method in the prior art can be expanded.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen flow measurement, in particular to a pVTt method hydrogen flow calibration device. Background Art

[0002] As an efficient and clean energy medium, hydrogen is increasingly used in the fields of energy, chemical industry, transportation, etc. With the rapid popularization of hydrogen fuel cell vehicles and the accelerated layout of hydrogen refueling stations, online metering of hydrogen refueling machines will enter a stage of rapid demand. Establishing a complete traceability chain can trace every link of hydrogen flow metering, thereby ensuring the accuracy and reliability of the metering results, and providing important technical support for hydrogen energy research and application. The traceability chain includes hydrogen sources, transmission pipelines, flow meters, data acquisition, data processing and data transmission, which can effectively avoid problems such as metering data tampering and error accumulation, improve the accuracy and credibility of hydrogen flow metering, and thus ensure the safe operation and sustainable development of the hydrogen energy industry.

[0003] Due to its highly flammable and explosive nature, hydrogen has extremely high requirements for the accuracy and reliability of its flow measurement. In the existing technology, air is often used as the medium and the pVTt (Pressure-Volume-Temperature method) is used to measure the hydrogen flow accuracy of the meter under test. However, due to the different physical properties of hydrogen and air such as density and viscosity, their flow characteristics are also different. Using air to track the flow of the hydrogen sonic nozzle is bound to have errors. When using air tracing, it is necessary to consider the errors that may be caused by these factors, and perform corresponding calibration and corrections. These corrections all rely on theoretical calculation results and lack verification of actual application scenarios of hydrogen. In addition to the difference in the calibration medium, the calibration temperature and pressure are also key factors affecting the accuracy of the results. The working environment of the medium or pVTt method in the prior art is usually a room temperature environment and a medium pressure environment within 10MPa. This type of calibration condition is very different from the application scenario environment of the hydrogen meter being tested (taking the flow meter actually used in the hydrogen refueling machine as an example, its working conditions are above -40°C, 35MPa or 70MPa, and the equipment for 90MPa application scenarios in the prior art is also being invested heavily in research). The accuracy of the calibration results under low temperature, high pressure or ultra-high pressure conditions cannot meet the precision requirements required for work only through theoretical calculations, and does not take into account the gas handling, high pressure or ultra-high pressure realization when applied to hydrogen media. At the same time, it also does not take into account the safety of the device itself and the calibration process when applied to hydrogen media. Utility Model Content

[0004] The utility model provides a pVTt method hydrogen flow rate calibration device, which is used to improve the temperature and pressure calibration condition range and calibration accuracy of the pVTt method in the prior art.

[0005] In order to solve the above problems, the utility model provides a pVTt method hydrogen flow calibration device, comprising a gas supply pipeline, a pressure regulating module, a heat exchange module, a gas storage and pressure stabilizing module, a hydrogen module to be tested, a measuring module and an exhaust pipeline arranged in sequence, the measuring module comprising a measuring component and a measuring tank, wherein the pressure regulating module, the heat exchange module, the gas storage and pressure stabilizing module, the hydrogen module to be tested and the measuring tank can be connected and disconnected in sequence and form a hydrogen calibration flow path with the gas supply pipeline and the exhaust pipeline; the measuring component is used to measure the time taken for hydrogen to flow into or out of the measuring tank and the temperature change and pressure change in the measuring tank, and the hydrogen module to be tested is used to measure the hydrogen flow rate flowing into the measuring tank; the pressure regulating module and the hydrogen module to be tested can be connected and disconnected and form a purge flow path with the gas supply pipeline and the exhaust pipeline.

[0006] Further, the purge flow path includes a hydrogen purge flow path and a nitrogen purge flow path, the gas supply pipeline includes a hydrogen supply pipeline and a nitrogen supply pipeline, the two ends of the hydrogen supply pipeline are respectively connected to the hydrogen supply equipment and the pressure regulating module in a switchable manner, and the two ends of the nitrogen supply pipeline are respectively connected to the nitrogen supply equipment and the hydrogen supply pipeline in a switchable manner; the pressure regulating module and the hydrogen module to be tested can be connected in a switchable manner and form a hydrogen purge flow path with the hydrogen supply pipeline and the exhaust pipeline; the pressure regulating module and the hydrogen module to be tested can be connected in a switchable manner and form a nitrogen purge flow path with the hydrogen supply pipeline, the nitrogen supply pipeline and the exhaust pipeline.

[0007] Furthermore, the pVTt method hydrogen flow calibration device also includes a gas storage tank, and the gas supply pipeline also includes a hydrogen supply main line. The two ends of the hydrogen supply main line are respectively connected to the hydrogen supply pipeline and the gas storage tank in a disconnectable manner, and the gas storage tank is connected to the pressure regulating module in a disconnectable manner. The pressure regulating module, the heat exchange module, the gas storage and pressure stabilizing module, the hydrogen module to be tested, and the measuring tank are connected in sequence in a disconnectable manner and form a hydrogen calibration flow path with the hydrogen supply pipeline, the hydrogen supply main line, and the exhaust pipeline.

[0008] Furthermore, the pVTt method hydrogen flow calibration device also includes an input pipeline, an exhaust pipeline equipped with a first vacuum pump, and an openable and closable environmental chamber. The hydrogen module to be tested is installed in the environmental chamber. The environmental chamber is connected to the exhaust pipeline in a switchable manner through the exhaust pipeline. The environmental chamber is connected to the gas supply pipeline or the external environment in a switchable manner through the input pipeline. The first vacuum pump is used to extract the fluid in the environmental chamber along the exhaust pipeline.

[0009] Furthermore, the pVTt method hydrogen flow calibration device also includes a hydrogen detector, which is used to detect the hydrogen concentration in the environmental chamber to control the on-off of the input pipeline and the exhaust pipeline according to the hydrogen concentration in the environmental chamber.

[0010] Furthermore, the pVTt method hydrogen flow calibration device also includes a circulation module, and two ends of the circulation module are respectively connected to the gas supply pipeline and the exhaust pipeline in a disconnectable manner to form a circulation flow path.

[0011] Furthermore, the pVTt method hydrogen flow calibration device also includes a drying device, the circulation module includes a circulation pipeline and a circulation pump, the two ends of the circulation pipeline are respectively connected to the gas supply pipeline and the exhaust pipeline in a switchable manner, and the circulation pump and the drying device are arranged at intervals on the circulation pipeline.

[0012] Furthermore, the gas storage pressure stabilizing module includes a pressure controller and a gas storage pressure stabilizing tank, the heat exchange module, the pressure controller and the gas storage pressure stabilizing tank are connected in sequence, and the gas storage pressure stabilizing tank is connected to the hydrogen module to be tested in an on-off manner.

[0013] Furthermore, the hydrogen module under test includes a temperature transmitter and a first tested group and a second tested group connected in parallel. Both ends of the first tested group and the second tested group are connected to the gas storage pressure stabilizing module and the measuring tank in a switchable manner. The temperature transmitter is arranged at the parallel inlet end of the first tested group and the second tested group. The first tested group includes a tested sonic nozzle and a differential pressure transmitter connected in parallel to the tested sonic nozzle. The second tested group includes a flow controller, a pressure transmitter and a tested flow meter arranged in sequence.

[0014] Furthermore, the measuring module also includes a second vacuum pump arranged on the connecting pipeline between the measuring tank and the exhaust pipeline, and the measuring component includes a timer, a thermometer and a pressure gauge. The timer is used to measure the time taken for hydrogen to flow into or out of the measuring tank, and the thermometer and pressure gauge are used to measure the temperature and pressure in the measuring tank respectively.

[0015] By applying the technical solution of the utility model, a pVTt method hydrogen flow calibration device is provided, comprising a gas supply pipeline, a pressure regulating module, a heat exchange module, a gas storage and pressure stabilizing module, a hydrogen module to be tested, a measuring module and an exhaust pipeline which are arranged in sequence, wherein the measuring module comprises a measuring component and a measuring tank, wherein the pressure regulating module, the heat exchange module, the gas storage and pressure stabilizing module, the hydrogen module to be tested and the measuring tank can be connected and disconnected in sequence and form a hydrogen calibration flow path with the gas supply pipeline and the exhaust pipeline; the measuring component is used to measure the time taken for hydrogen to flow into or out of the measuring tank and the temperature change and pressure change in the measuring tank, and the hydrogen module to be tested is used to measure the hydrogen flow rate flowing into or out of the measuring tank; the pressure regulating module and the hydrogen module to be tested can be connected and disconnected and form a purge flow path with the gas supply pipeline and the exhaust pipeline.

[0016] The tested modules of this scheme are mainly hydrogen modules (hydrogen sonic nozzles, etc.), so hydrogen is used as the test medium in the test flow path during the test process. This can avoid the situation where the test results are bound to have errors and require further theoretical calculations due to the differences in the physical properties and flow characteristics of hydrogen and air when the flow accuracy of the hydrogen module is tested with air as the medium, which is beneficial to improving the test accuracy. Furthermore, the pressure of hydrogen flowing through the hydrogen test flow path during the gas flow test is adjusted by the pressure regulating module to ensure that the gas supply pipeline can stably provide hydrogen at the pressure required for the test. The temperature of the hydrogen flowing through the hydrogen test flow path during the gas flow test is pre-adjusted by the heat exchange module to ensure that the gas supply pipeline can stably provide hydrogen at the temperature required for the test. This arrangement avoids the situation in the prior art where the pVTt method is first used to calibrate the medium at room temperature and medium pressure, and then the flow accuracy under the required working conditions is obtained through theoretical calculation. The pVTt method hydrogen flow calibration device of this scheme has a wider range of calibration conditions such as high pressure and low temperature through the pressure regulating module and the heat exchange module. The pressure and temperature of the calibration medium corresponding to the module under test can be directly adjusted and the flow calibration can be performed, which improves the calibration efficiency and further improves the calibration accuracy, while improving the applicability of the pVTt method hydrogen flow calibration device. On the other hand, before the flow calibration is performed, the inside of the device can be purged through the purge flow path to ensure the safety of the device when performing hydrogen flow calibration, which is also conducive to improving the calibration accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0018] Figure 1 The schematic diagram of the structure of the pVTt method hydrogen flow calibration device provided in the embodiment of the utility model is shown.

[0019] The above drawings include the following reference numerals:

[0020] 1. First switch valve; 2. Second switch valve; 3. Third switch valve; 4. Pressure regulating module; 5. Fourth switch valve; 6. Heat exchange module; 7. Pressure controller; 8. Gas storage pressure stabilizing tank; 9. Fifth switch valve; 10. Sixth switch valve; 11. Flow controller; 12. Flow meter to be tested; 13. Temperature transmitter; 14. Pressure transmitter; 15. Seventh switch valve; 16. Sonic nozzle to be tested; 17. Differential pressure transmitter; 18. Eighth switch valve; 19. Ninth switch valve; 20. Tenth switch valve; 21. Measuring tank; 22. Timer; 23. Thermometer; 24. Pressure gauge; 25 , the eleventh switch valve; 26, the second vacuum pump; 27, the twelfth switch valve; 28, the thirteenth switch valve; 29, the circulation pump; 30, the drying device; 31, the fourteenth switch valve; 32, the fifteenth switch valve; 33, the gas storage tank; 34, the sixteenth switch valve; 35, the seventeenth switch valve; 36, the eighteenth switch valve; 37, the nineteenth switch valve; 38, the environmental chamber; 39, the first vacuum pump; 40, the twentieth switch valve; 41, the hydrogen supply pipeline; 42, the nitrogen supply pipeline; 43, the main hydrogen supply pipeline; 44, the input pipeline; 45, the discharge pipeline; 46, the circulation pipeline; 47, the exhaust pipeline. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0022] like Figure 1 As shown, an embodiment of the utility model provides a pVTt method hydrogen flow calibration device, including a gas supply pipeline, a pressure regulating module 4, a heat exchange module 6, a gas storage and pressure stabilizing module, a hydrogen module to be tested, a measuring module and an exhaust pipeline 47 arranged in sequence, and the measuring module includes a measuring component and a measuring tank 21, wherein the pressure regulating module 4, the heat exchange module 6, the gas storage and pressure stabilizing module, the hydrogen module to be tested, and the measuring tank 21 can be connected and disconnected in sequence and form a hydrogen calibration flow path with the gas supply pipeline and the exhaust pipeline 47; the measuring component is used to measure the time taken for hydrogen to flow into or out of the measuring tank 21 and the temperature change and pressure change in the measuring tank 21, and the hydrogen module to be tested is used to measure the hydrogen flow rate flowing into the measuring tank 21; the pressure regulating module 4 and the hydrogen module to be tested can be connected and disconnected and form a purge flow path with the gas supply pipeline and the exhaust pipeline 47.

[0023] The tested module of this embodiment is mainly a hydrogen module (hydrogen sonic nozzle, etc.), so the test medium in the test flow path during the test process uses hydrogen. This can avoid the situation where the test results are bound to have errors and require further theoretical calculations due to the differences in the physical properties and flow characteristics of hydrogen and air when the air medium is used to test the flow accuracy of the hydrogen module, which is beneficial to improving the test accuracy. Furthermore, the pressure of the hydrogen flowing through the hydrogen test flow path during the gas flow test is adjusted by the pressure regulating module 4 to ensure that the gas supply pipeline can stably provide hydrogen at the pressure required for the test, and the temperature of the hydrogen flowing through the hydrogen test flow path during the gas flow test is pre-adjusted by the heat exchange module 6 to ensure that the gas supply pipeline can stably provide hydrogen at the temperature required for the test. This arrangement avoids the situation in the prior art where the pVTt method is first used to obtain the flow calibration of the medium at room temperature and medium pressure, and then the flow accuracy of the medium under the required working conditions is obtained through theoretical calculation. The pVTt method hydrogen flow calibration device of this embodiment has a wider range of calibration conditions such as high pressure and low temperature through the pressure regulating module 4 and the heat exchange module 6. The pressure and temperature of the calibration medium corresponding to the module under test can be directly adjusted and the flow calibration can be performed, which improves the calibration efficiency and further improves the calibration accuracy, while improving the applicability of the pVTt method hydrogen flow calibration device. On the other hand, before the flow calibration is performed, the inside of the device can be purged through the purge flow path to ensure the safety of the device when performing hydrogen flow calibration, and at the same time it is beneficial to improve the calibration accuracy.

[0024] It should be noted that the pVTt method calculates the mass flow rate of the gas by measuring the amount of gas entering or flowing out of the volume container within a certain time interval, as well as the corresponding pressure and temperature. The pVTt method hydrogen flow measurement principle in this embodiment includes: the measuring tank 21 serves as a standard container and can be connected to the hydrogen calibration flow path in an on-off manner, and its capacity or volume is known. Before starting the detection, hydrogen with the required pressure and temperature is obtained through the pressure regulating module 4 and the heat exchange module 6. After the detection starts, hydrogen is discharged from the hydrogen module to be detected and starts to flow into the measuring tank 21. At the same time, timing is started to record the time of hydrogen inflow and the temperature and pressure in the measuring tank 21 at the beginning, until the hydrogen discharged from the hydrogen module to be detected stops flowing into the measuring tank 21. The timing is stopped and the pressure and temperature before and after the hydrogen flows in are recorded. Combined with the formula PV=nRT and Q=△V / t (where n is the number of moles of gas, R is the ideal gas constant, T is the absolute temperature, △V is the volume change of gas, and t is the flow time), the mass flow rate of hydrogen can be calculated by recording the volume change of hydrogen and the corresponding pressure change and temperature change. Specifically, the difference in the mass of hydrogen in the measuring tank 21 at the end time and the initial time is calculated, and the mass flow rate flowing into the measuring tank 21 is obtained by dividing the hydrogen mass increment by the recorded time, and compared with the mass flow rate flowing through the hydrogen module to be detected (wherein the mass flow rate of the hydrogen module to be detected can be calculated based on the hydrogen flow rate detected by it), and then the meter to be tested is evaluated or calibrated.

[0025] It can be understood that the hydrogen flow rate measured by the hydrogen module under test is the theoretical hydrogen flow rate theoretically input into the measuring tank 21, which corresponds to the theoretical hydrogen mass flow rate. The hydrogen mass flow rate calculated at the measuring tank 21 by the pVTt method is the actual hydrogen mass flow rate. The evaluation and calibration of the hydrogen module under test is achieved by comparing the theoretical hydrogen mass flow rate with the actual hydrogen mass flow rate.

[0026] Specifically, the purge flow path includes a hydrogen purge flow path and a nitrogen purge flow path, the gas supply pipeline includes a hydrogen supply pipeline 41 and a nitrogen supply pipeline 42, the two ends of the hydrogen supply pipeline 41 are respectively connected to the hydrogen supply equipment and the pressure regulating module 4 in a switchable manner, and the two ends of the nitrogen supply pipeline 42 are respectively connected to the nitrogen supply equipment and the hydrogen supply pipeline 41 in a switchable manner; the pressure regulating module 4 and the hydrogen module to be tested are connected in a switchable manner and form a hydrogen purge flow path with the hydrogen supply pipeline 41 and the exhaust pipeline 47; the pressure regulating module 4 and the hydrogen module to be tested are connected in a switchable manner and form a nitrogen purge flow path with the hydrogen supply pipeline 41, the nitrogen supply pipeline 42 and the exhaust pipeline 47.

[0027] In this way, nitrogen and hydrogen can be purged before the calibration to ensure the safety of the calibration. Furthermore, by setting the hydrogen supply pipeline 41 or the nitrogen supply pipeline 42 and other components to be switchable, the safe switching of hydrogen, nitrogen and air can be ensured during the calibration process or the maintenance of the device, and the safe isolation of hydrogen and air can be ensured.

[0028] Further, the pVTt method hydrogen flow calibration device also includes a gas storage tank 33, and the gas supply pipeline also includes a hydrogen supply main path 43. The two ends of the hydrogen supply main path 43 are respectively connected to the hydrogen supply pipeline 41 and the gas storage tank 33 in a disconnectable manner. The gas storage tank 33 is connected to the pressure regulating module 4 in a disconnectable manner. The pressure regulating module 4, the heat exchange module 6, the gas storage and pressure stabilizing module, the hydrogen module to be tested, and the measuring tank 21 are sequentially connected in a disconnectable manner and form a hydrogen calibration flow path with the hydrogen supply pipeline 41, the hydrogen supply main path 43, and the exhaust pipeline 47. It can be understood that there can be multiple gas storage tanks 33 in this embodiment, and the number of gas storage tanks 33 can be set according to actual conditions.

[0029] In this embodiment, when using the pVTt method hydrogen flow calibration device, hydrogen is first supplied to the gas storage tank 33 through the hydrogen supply main path 43. After the hydrogen pressure in the gas storage tank 33 reaches a set value, the gas supply is stopped, and the preparation of the calibration gas is completed.

[0030] like Figure 1 As shown, the pVTt method hydrogen flow calibration device also includes an input pipeline 44, an exhaust pipeline 45 equipped with a first vacuum pump 39, and an openable and closable environmental chamber 38. The hydrogen module to be tested is installed in the environmental chamber 38. The environmental chamber 38 is connected to the exhaust pipeline 47 in a switchable manner through the exhaust pipeline 45. The environmental chamber 38 is connected to the gas supply pipeline or the external environment in a switchable manner through the input pipeline 44. The first vacuum pump 39 is used to extract the fluid in the environmental chamber 38 along the exhaust pipeline 45.

[0031] In this arrangement, nitrogen is filled into the environmental chamber 38 to provide a slightly positive pressure pure nitrogen environment. The hydrogen module and tooling under inspection are in the nitrogen environment of the environmental chamber 38, which plays an isolation and protection role, prevents the risk of sudden leakage and explosion, and improves the safety of the inspection.

[0032] Specifically, the pVTt method hydrogen flow calibration device also includes a hydrogen detector, which is used to detect the hydrogen concentration in the environmental chamber 38 to control the on-off of the input pipeline 44 and the exhaust pipeline 45 according to the hydrogen concentration in the environmental chamber 38.

[0033] With this arrangement, the hydrogen concentration in the environmental chamber 38 can be measured by the hydrogen detector to determine whether there is a hydrogen leakage, thereby preventing measurement inaccuracies and safety accidents caused by leakage.

[0034] Preferably, after determining that hydrogen leakage has occurred, the nitrogen and hydrogen in the environmental chamber 38 can be exhausted through the exhaust pipe 45, and then air can be input into the environmental chamber 38 through the input pipe 44 to stabilize the interior of the environmental chamber at normal pressure.

[0035] Furthermore, the pVTt method hydrogen flow calibration device also includes a circulation module, and the two ends of the circulation module are respectively connected to the gas supply pipeline and the exhaust pipeline 47 to form a circulation flow path. This arrangement realizes the recycling of hydrogen, reduces hydrogen consumption, reduces the use cost, hydrogen storage cost and the impact of hydrogen emissions on the environment.

[0036] like Figure 1 As shown, the pVTt method hydrogen flow calibration device also includes a drying device 30, and the circulation module includes a circulation pipeline 46 and a circulation pump 29. The two ends of the circulation pipeline 46 are respectively connected to the gas supply pipeline and the exhaust pipeline 47 in a switchable manner, and the circulation pump 29 and the drying device 30 are arranged on the circulation pipeline 46 at intervals. In this way, the moisture in the recovered hydrogen is removed by the drying device 30 to ensure the dryness and purity of the hydrogen in the hydrogen circulation system. Specifically, the circulation pipeline 46 in this embodiment is connected to the main hydrogen supply road 43 in a switchable manner, and the hydrogen recovered by the circulation module is recovered into the gas storage tank 33 to achieve safe storage and buffering of the recovered hydrogen to prevent leakage and explosion risks, wherein the gas storage tank 33 stores enough hydrogen to meet the requirements of the calibration process.

[0037] like Figure 1 As shown, the gas storage and pressure stabilizing module includes a pressure controller 7 and a gas storage and pressure stabilizing tank 8. The heat exchange module 6, the pressure controller 7 and the gas storage and pressure stabilizing tank 8 are connected in sequence, and the gas storage and pressure stabilizing tank 8 is connected to the hydrogen module to be tested in an on-off manner.

[0038] In this embodiment, the gas storage pressure-stabilizing tank 8 is used to store the hydrogen after pressure regulation and temperature control by the pressure regulating module 4 and the heat exchange module 6, and the pressure controller 7 is used to buffer and balance the pressure fluctuation of the hydrogen after pressure regulation by the pressure regulating module 4, so as to ensure the stability of the hydrogen pressure during the calibration process.

[0039] like Figure 1 As shown, the hydrogen module to be inspected includes a temperature transmitter 13 and a first inspected group and a second inspected group in parallel. Both ends of the first inspected group and the second inspected group are connected to the gas storage and pressure stabilizing module and the measuring tank 21 in a switchable manner. The temperature transmitter 13 is arranged at the parallel inlet end of the first inspected group and the second inspected group. The first inspected group includes a sonic nozzle 16 to be inspected and a differential pressure transmitter 17 connected in parallel to the sonic nozzle 16. The second inspected group includes a flow controller 11, a pressure transmitter 14 and a flow meter 12 to be inspected, which are arranged in sequence. It can be understood that when both ends of the first inspected group and the second inspected group correspond to the gas storage and pressure stabilizing module and the measuring tank 21 in a switchable manner, the flow path formed is a partial flow path of the hydrogen inspection flow path; when both ends of the first inspected group and the second inspected group correspond to the pressure regulating module 4 and the exhaust pipeline 47 in a switchable manner, the flow path formed is a partial flow path of the purge flow path.

[0040] This arrangement facilitates adjustment of the hydrogen flow path according to the actual module to be tested, and improves the applicability and test efficiency of the hydrogen flow test device of the pVTt method. Specifically, during the test process, when the test object is the sonic nozzle 16 to be tested, the hydrogen output from the gas storage tank 8 flows through the first group to be tested, and when the test object is the flow meter 12 to be tested, the hydrogen output from the gas storage tank 8 flows through the second group to be tested, and the temperature transmitter 13 is used to monitor the temperature of the hydrogen flowing to the first group to be tested and the second group to be tested, so as to adjust the hydrogen temperature in time through the heat exchange module 6.

[0041] The pVTt method hydrogen flow calibration device has a pressure-maintaining leak detection process. Compared with the purge flow path, the pressure-maintaining flow path is formed by the gas supply pipeline, the pressure regulating module 4, and the hydrogen module to be tested being connected and disconnected in sequence. During the pressure-maintaining process, the input hydrogen or nitrogen is pressurized by the pressure regulating module 4 and transported to the hydrogen module to be tested by the gas supply pipeline. After the pressure is increased to the predetermined pressure-maintaining pressure, the connection between the hydrogen module to be tested and other modules is closed and disconnected, and the pressure-maintaining time is set to start pressure-maintaining. The pressure value of the pressure transmitter 14 or the differential pressure transmitter 17 before and after the pressure-maintaining is recorded and the pressure drop before and after the pressure-maintaining is calculated to determine the sealing of the device.

[0042] Furthermore, the flow controller 11 and the pressure controller 7 are used to make the hydrogen flow rate flowing through the flow meter 12 or the sonic nozzle 16 reach the flow value to be tested during the calibration process, and make the hydrogen in the gas storage tank 8 in a dynamic equilibrium state.

[0043] like Figure 1 As shown, the measuring module further includes a second vacuum pump 26 disposed on the communication pipeline between the measuring tank 21 and the exhaust pipeline 47, and the measuring assembly includes a timer 22, a thermometer 23 and a pressure gauge 24. The timer 22 is used to measure the time taken for hydrogen to flow into or out of the measuring tank 21, and the thermometer 23 and the pressure gauge 24 are used to measure the temperature and pressure in the measuring tank 21, respectively. It can be understood that there can be multiple measuring tanks 21 in this embodiment, and the number of measuring tanks 21 can be set according to actual conditions.

[0044] It can be understood that the pVTt method hydrogen flow calibration device provided by the utility model includes an intelligent control module and multiple safety valves. Any connection and disconnection is achieved through the safety valve. Each component and the switch valve are connected to the intelligent control module. Specific functional programs (such as one-time nitrogen purge, one-time hydrogen pressure maintenance, etc.) are set through the intelligent control module to control the opening and closing of each component and multiple switch valves to achieve quick and safe operation.

[0045] It should be noted that this device has a safety interlocking function. This device and the area where the device is located use simulation analysis methods to identify risk areas, reasonably set detection positions, and form a safety linkage system with the pressure monitoring devices in each component. When leakage or abnormal sudden drop in local pressure is detected, the gas source can be cut off in the first time and discharged safely;

[0046] In summary, the utility model provides a pVTt method hydrogen flow calibration device, which realizes the safety, environmental protection and economic basis of hydrogen as the medium calibration through the combination of a circulation module, an environmental chamber 38 and the switchable adjustment of multiple flow paths. The pressure regulating module 4 and the heat exchange module 6 are used to achieve the metrological calibration conditions under high pressure and low temperature. The whole set of equipment adopts a set of high-pressure intelligent control hydrogen circulation calibration modules, and takes into account the quick operation and safety interlocking functions to achieve quick and safe operation. The whole set of equipment can realize the online real flow circulation calibration of hydrogen of the sonic nozzle and flow meter.

[0047] In this embodiment, the plurality of switch valves include a first switch valve 1, a second switch valve 2, a third switch valve 3, a fourth switch valve 5, a fifth switch valve 9, a sixth switch valve 10, a seventh switch valve 15, an eighth switch valve 18, a ninth switch valve 19, a tenth switch valve 20, an eleventh switch valve 25, a twelfth switch valve 27, a thirteenth switch valve 28, a fourteenth switch valve 31, a fifteenth switch valve 32, a sixteenth switch valve 34, a seventeenth switch valve 35, an eighteenth switch valve 36, a nineteenth switch valve 37, and a twentieth switch valve 40. The plurality of switch valves are arranged at positions such as Figure 1 As shown, the process of the pVTt method hydrogen flow calibration device provided by the utility model includes:

[0048] 1. Connect the hydrogen module to be tested:

[0049] Start the device system, start the system and safety self-check, open the environmental chamber 38 after confirmation, connect the inspected meter (the inspected flow meter 12 and the inspected sonic nozzle 16) on the special tooling, and close the environmental chamber 38;

[0050] 2. Nitrogen purge:

[0051] 2.1: Open the second switch valve 2, the third switch valve 3, the eighteenth switch valve 36, the sixth switch valve 10 or the seventh switch valve 15 (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested), and the ninth switch valve 19;

[0052] 2.2: Open the first switch valve 1, completely connect the nitrogen purge flow path, introduce nitrogen for purge, and close all valves after the purge is completed;

[0053] 3. Nitrogen pressure maintenance:

[0054] 3.1: Open the second switch valve 2, the third switch valve 3, the eighteenth switch valve 36, the sixth switch valve 10 or the seventh switch valve 15 (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested).

[0055] 3.2: Open the first switch valve 1, completely connect the pressure-maintaining flow path, introduce nitrogen, and start the pressure regulating module 4 to start pressurization;

[0056] 3.3: After the pressure is increased to the predetermined holding pressure, the first switch valve 1, the second switch valve 2, the third switch valve 3, the eighteenth switch valve 36 and the pressure regulating module 4 are closed, and the holding time is set to start holding pressure;

[0057] 3.4: After the pressure maintenance is completed, record the pressure value of the pressure transmitter 14 or the differential pressure transmitter 17 after the pressure maintenance (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested);

[0058] 3.5: Calculate the pressure drop before and after pressure maintenance to determine the sealing performance of the device;

[0059] 3.6: If the pressure holding result does not meet the requirements, check the leak point and reconnect it and repeat the process described in steps 2.1 to 3.4;

[0060] 3.7: If the pressure holding result meets the requirements, open the ninth switch valve 19 to release the nitrogen in the pipeline, and close all the switch valves after the nitrogen is released.

[0061] 4. Nitrogen environmental protection:

[0062] 4.1: When all the switch valves are closed as described in step 3.7, open the tenth switch valve 20, turn on the first vacuum pump 39, and extract the air in the environment chamber 38. When the vacuum degree of the environment chamber 38 is less than or equal to the required value, close the tenth switch valve 20 and the first vacuum pump 39, and stop vacuuming;

[0063] 4.2: Open the first switch valve 1 and the seventeenth switch valve 35 to fill nitrogen into the environmental chamber 38;

[0064] 4.3: When the nitrogen in the environment chamber 38 reaches the required value, close the first switch valve 1 and the seventeenth switch valve 35 to maintain the nitrogen environment in the environment chamber 38, and all the switch valves are in the closed state;

[0065] 4.4: The hydrogen module and tooling under inspection are placed in a nitrogen environment, providing hydrogen leakage monitoring conditions to ensure that hydrogen does not come into contact with air when leakage and explosion occur;

[0066] 5. Hydrogen purge:

[0067] 5.1: When all the switch valves are closed as described in step 4.3, open the third switch valve 3, the eighteenth switch valve 36, the sixth switch valve 10 or the seventh switch valve 15 (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested), and the ninth switch valve 19;

[0068] 5.2: Open the nineteenth switch valve 37 to completely connect the nitrogen purge flow path, introduce hydrogen for purge, and close all valves after the purge is completed;

[0069] 6. Hydrogen pressure maintenance and leak detection:

[0070] 6.1: When all the switch valves are closed as described in step 5.2, open the third switch valve 3, the eighteenth switch valve 36, the sixth switch valve 10 or the seventh switch valve 15 (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested);

[0071] 6.2: Open the nineteenth switch valve 37, completely connect the pressure-maintaining flow path and introduce hydrogen, start the pressure-regulating module 4 to start increasing the pressure to the pressure-maintaining pressure;

[0072] 6.2: After the pressure is increased to the predetermined holding pressure, the nineteenth switch valve 37, the third switch valve 3, the eighteenth switch valve 36 and the pressure regulating module 4 are closed, and the holding time is set to start holding the pressure. At the same time, the hydrogen detector is used to check the air tightness of the key components and joints in the pipeline;

[0073] 6.4: After the pressure maintenance is completed, record the pressure value of the pressure transmitter 14 or the differential pressure transmitter 17 after the pressure maintenance (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested);

[0074] 6.5: Calculate the pressure drop before and after pressure maintenance to determine the sealing performance of the device;

[0075] 6.6: If the pressure holding result does not meet the requirements, open the ninth switch valve 19 to release the hydrogen in the pipeline, and perform nitrogen purge according to the process described in 1 to 2.2;

[0076] 6.7: Under the conditions described in step 6.6, draw out the nitrogen in the environmental chamber 38, let in air, open the environmental chamber 38 to check for leaks, reconnect, and repeat steps 1 to 6.5;

[0077] 6.8: If the pressure holding result meets the requirements, open the ninth switch valve 19 to release the hydrogen in the pipeline, and close all the switch valves after the hydrogen is released;

[0078] 7. Gas tank 33 replenishment:

[0079] When all the switch valves are closed as described in 6.8, the nineteenth switch valve 37 and the fifteenth switch valve 32 are opened to fill the gas storage tank 33 with hydrogen. When the pressure in the gas storage tank 33 reaches the set value, the nineteenth switch valve 37 and the fifteenth switch valve 32 are closed to complete the gas replenishment. All the switch valves are in the closed state.

[0080] 8. Preparation of test gas:

[0081] 8.1: When all the switch valves are closed in step 7, open the sixteenth switch valve 34 and the fourth switch valve 5 to release the hydrogen in the gas storage tank 33;

[0082] 8.2: Start the pressure regulating module 4 and the heat exchange module 6, and control the pressure controller 7 to make the hydrogen in the gas storage pressure stabilizing tank 8 reach a predetermined pressure and temperature;

[0083] 8.3: Close the sixteenth switch valve 34, the fourth switch valve 5 and the pressure regulating module 4, and stabilize the gas storage pressure stabilizing tank 8 for a certain period of time so that the hydrogen reaches a uniform and stable state, and all the switch valves are in the closed state;

[0084] 9. Measurement preparation:

[0085] 9.1: When all the switch valves in step 8.3 are closed, open the eleventh switch valve 25;

[0086] 9.2: Start the second vacuum pump 26 to extract the gas in the measuring tank 21;

[0087] 9.2.1: When the gas in the measuring tank 21 is air or nitrogen, open the twelfth switch valve 27 to drain;

[0088] 9.2.2: When the gas in the measuring tank 21 is hydrogen, open the thirteenth switch valve 28 and the fourteenth switch valve 31, start the circulation pump 29, and circulate the gas in the measuring tank 21 back to the gas storage tank 33;

[0089] 9.3: In the process described in step 9.2, after the gas pressure in the measuring tank 21 is less than the predetermined vacuum pressure value, the eleventh switch valve 25 and the second vacuum pump 26 are closed, and the vacuuming of the measuring tank 21 is completed.

[0090] 9.3.1: When the gas in the measuring tank 21 is air or nitrogen, close the twelfth switch valve 27;

[0091] 9.3.2: When the gas in the measuring tank 21 is hydrogen, close the thirteenth switch valve 28, the fourteenth switch valve 31 and the circulation pump 29;

[0092] 9.4: After completing the process described in step 9.3, all switch valves are in a closed state;

[0093] 10.Stable flow:

[0094] 10.1: When all the switch valves are closed as described in step 9.4, open the eighth switch valve 18, the fifth switch valve 9, and open the sixth switch valve 10 or the seventh switch valve 15 (open the sixth switch valve 10 when the metering object is the flow meter 12 to be tested, and open the seventh switch valve 15 when the metering object is the sonic nozzle 16 to be tested);

[0095] 10.2: Under the state described in step 10.1, open the sixteenth switch valve 34 and the fourth switch valve 5 at the same time, start the pressure regulating module 4 and the heat exchange module 6, and make the meter under test stabilize at the flow value under test;

[0096] 10.2.1: When the object to be inspected is the inspected flowmeter 12, adjust the flow controller 11 so that the hydrogen flow rate flowing through the inspected flowmeter 12 reaches the inspected flow value, and the hydrogen in the gas storage pressure stabilizing tank 8 is in a dynamic equilibrium state;

[0097] 10.2.2: When the object to be inspected is the sonic nozzle 16, the pressure controller 7 is controlled so that the differential pressure transmitter 17 reaches the back pressure ratio of the inspected meter, and the hydrogen in the gas storage tank 8 is in a dynamic equilibrium state.

[0098] 10.3: Keep the meter under test (flow meter 12 or sonic nozzle 16) under stable pressure or flow conditions for more than 30 seconds;

[0099] 11. Air tightness monitoring:

[0100] 11.1: Under the conditions described in step 10.3, the hydrogen concentration in the environmental chamber 38 is continuously monitored using a hydrogen detector;

[0101] 11.2: If leakage or explosion is found, shut down the machine immediately, close all the switch valves and functional modules, and open the ninth switch valve 19 to exhaust the hydrogen;

[0102] 11.3: While performing the operations described in step 11.2, open the tenth switch valve 20, open the first vacuum pump 39 to extract the gas in the environment chamber 38, open the first switch valve 1 and the seventeenth switch valve 35, and fill the environment chamber 38 with nitrogen for purging;

[0103] 11.3.1: When there is leakage as described in steps 11.2 to 11.3, close the first switch valve 1 and the seventeenth switch valve 35 after the purge is completed, open the twentieth switch valve 40 to fill air to normal pressure, close all switch valves after the filling is completed, open the environmental chamber to check the leakage point and reconnect, and repeat steps 1 to 11.1;

[0104] 11.3.2: When the explosion occurs as described in steps 11.2 to 11.3, close the first switch valve 1 and the seventeenth switch valve 35 after the purge is completed, open the twentieth switch valve 40 and fill in air to normal pressure, the test is terminated, and all switch valves and functional modules are closed;

[0105] 12. Hydrogen supplement:

[0106] During the process described in step 10, when the hydrogen supply in the gas storage tank 33 is insufficient to maintain the dynamic stability described in step 10, the nineteenth switch valve 37 and the fifteenth switch valve 32 are opened, and hydrogen is replenished into the gas storage tank 33 through the hydrogen source. After the replenishment is completed, the nineteenth switch valve 37 and the fifteenth switch valve 32 are closed;

[0107] 13. Flow measurement:

[0108] 13.1: When the flow rate is stable before the verification in step 10, start the timer 22, use the thermometer 23 and the pressure gauge 24 to simultaneously record the temperature and pressure of the hydrogen in the measuring tank 21 at the initial time, and calculate the mass of the hydrogen in the measuring tank at the initial time;

[0109] 13.2: After the hydrogen in the measuring tank 21 flows for a predetermined time (generally not less than 30 seconds), stop timing, use the thermometer 23 and the pressure gauge 24 to simultaneously record the temperature and pressure of the hydrogen in the measuring tank 21 at the end time, and calculate the mass of the hydrogen in the measuring tank at the end time;

[0110] 13.3: Calculate the difference in hydrogen mass in the measuring tank 21 at the end time and the initial time, divide the hydrogen mass increment by the recorded time to obtain the mass flow rate flowing into the measuring tank 21, and compare it with the mass flow rate flowing through the meter under test (the flow meter under test 12 or the sonic nozzle under test 16), and then evaluate or calibrate the meter under test;

[0111] 13.4: Continuous measurement: After the process described in steps 13.1 to 13.2, reset the verification conditions and repeat the process described in steps 11.3 to 13.3 to perform continuous measurement;

[0112] 13.5: After the measurement process described in steps 13.1 to 13.4 is completed, all switch valves and functional modules are closed;

[0113] 14. Gas recovery:

[0114] 14.1: After all the measuring points of the measuring process described in step 13 are completed, all the switch valves and functional modules are in the closed state, and the fifth switch valve 9, the sixth switch valve 10 or the seventh switch valve 15 (the sixth switch valve 10 is opened when the metering object is the flow meter 12 to be tested, and the seventh switch valve 15 is opened when the metering object is the sonic nozzle 16 to be tested), the eighth switch valve 18, the eleventh switch valve 25, the thirteenth switch valve 28, and the fourteenth switch valve 31 are opened;

[0115] 14.2: Start the second vacuum pump 26 and the circulation pump 29, pump the hydrogen in the gas storage pressure stabilizing tank 8, the measuring tank 21 and the pipeline to normal pressure, and circulate it back to the gas storage tank 33, then close all the switch valves, the second vacuum pump 26 and the circulation pump 29;

[0116] 15.Purge after test:

[0117] 15.1: With all the switch valves in step 14.2 closed, repeat step 2 to perform nitrogen purge, and after the purge is completed, close all the switch valves;

[0118] 15.2: When all the switch valves in step 15.1 are closed, open the tenth switch valve 20, open the first vacuum pump 39 to extract the nitrogen in the environment chamber 38, open the twentieth switch valve 40 to fill the air to normal pressure, and then close all the switch valves and the first vacuum pump 39;

[0119] 16. Disassemble the inspected meter (the inspected flow meter 12 and the inspected sonic nozzle 16):

[0120] In step 15.2, when all the switch valves are closed, open the environmental chamber 38, disassemble the inspected meter (the inspected flow meter 12 and the inspected sonic nozzle 16), and then close the environmental chamber 38;

[0121] 17. Leak detection after testing:

[0122] When all the switch valves are closed as described in step 16, use a hydrogen detector to check the air tightness of the hydrogen storage pipelines, components and connections.

[0123] Note: In the above process, the status of the switch valve is closed by default unless it is stated to be open.

[0124] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0125] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the utility model. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0126] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0127] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0128] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.

[0129] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A pVTt method hydrogen flow calibration device, characterized in that: The invention comprises a gas supply pipeline, a pressure regulating module (4), a heat exchange module (6), a gas storage and pressure stabilizing module, a hydrogen module to be tested, a measuring module and an exhaust pipeline (47) which are arranged in sequence, wherein the measuring module comprises a measuring component and a measuring tank (21), wherein: The pressure regulating module (4), the heat exchange module (6), the gas storage and pressure stabilizing module, the hydrogen module to be tested, and the measuring tank (21) are sequentially connected and disconnectable and form a hydrogen testing flow path with the gas supply pipeline and the exhaust pipeline (47); the measuring component is used to measure the time taken for hydrogen to flow into or out of the measuring tank (21) and the temperature change and pressure change in the measuring tank (21); the hydrogen module to be tested is used to measure the flow rate of hydrogen flowing into the measuring tank (21); The pressure regulating module (4) and the hydrogen module to be tested can be connected in an on-off manner and form a purge flow path with the gas supply pipeline and the exhaust pipeline (47).

2. The pVTt method hydrogen flow calibration device according to claim 1, characterized in that: The purge flow path comprises a hydrogen purge flow path and a nitrogen purge flow path, the gas supply pipeline comprises a hydrogen supply pipeline (41) and a nitrogen supply pipeline (42), the two ends of the hydrogen supply pipeline (41) are respectively connected to the hydrogen supply equipment and the pressure regulating module (4) in a switchable manner, and the two ends of the nitrogen supply pipeline (42) are respectively connected to the nitrogen supply equipment and the hydrogen supply pipeline (41) in a switchable manner; The pressure regulating module (4) and the hydrogen module to be tested can be connected in an on-off manner and form the hydrogen purge flow path with the hydrogen supply pipeline (41) and the exhaust pipeline (47); The pressure regulating module (4) and the hydrogen module to be tested can be connected in an on-off manner and form the nitrogen purge flow path with the hydrogen supply pipeline (41), the nitrogen supply pipeline (42) and the exhaust pipeline (47).

3. The pVTt method hydrogen flow calibration device according to claim 2, characterized in that: The pVTt method hydrogen flow calibration device further comprises a gas storage tank (33), the gas supply pipeline further comprises a hydrogen supply main path (43), two ends of the hydrogen supply main path (43) are respectively connected to the hydrogen supply pipeline (41) and the gas storage tank (33) in an on-off manner, and the gas storage tank (33) is connected to the pressure regulating module (4) in an on-off manner. The pressure regulating module (4), the heat exchange module (6), the gas storage and pressure stabilizing module, the hydrogen module to be tested, and the measuring tank (21) are sequentially connected and disconnectable to form a hydrogen testing flow path with the hydrogen supply pipeline (41), the main hydrogen supply path (43), and the exhaust pipeline (47).

4. The pVTt method hydrogen flow calibration device according to claim 1, characterized in that: The pVTt method hydrogen flow calibration device also includes an input pipeline (44), a discharge pipeline (45) equipped with a first vacuum pump (39), and an openable and closable environmental chamber (38); the hydrogen module to be tested is installed in the environmental chamber (38); the environmental chamber (38) is connected to the exhaust pipeline (47) in an on-off manner through the discharge pipeline (45); the environmental chamber (38) is connected to the gas supply pipeline or the external environment in an on-off manner through the input pipeline (44); and the first vacuum pump (39) is used to extract the fluid in the environmental chamber (38) along the discharge pipeline (45).

5. The pVTt method hydrogen flow calibration device according to claim 4, characterized in that: The pVTt method hydrogen flow calibration device also includes a hydrogen detector, which is used to detect the hydrogen concentration in the environmental chamber (38) so as to control the on-off of the input pipeline (44) and the discharge pipeline (45) according to the hydrogen concentration in the environmental chamber (38).

6. The pVTt method hydrogen flow calibration device according to claim 1, characterized in that: The pVTt method hydrogen flow calibration device also includes a circulation module, and two ends of the circulation module are respectively connected to the gas supply pipeline and the exhaust pipeline (47) in an on-off manner to form a circulation flow path.

7. The pVTt method hydrogen flow calibration device according to claim 6, characterized in that: The pVTt method hydrogen flow calibration device further comprises a drying device (30), the circulation module comprises a circulation pipeline (46) and a circulation pump (29), the two ends of the circulation pipeline (46) are respectively connected to the gas supply pipeline and the exhaust pipeline (47) in an on-off manner, and the circulation pump (29) and the drying device (30) are arranged on the circulation pipeline (46) at intervals.

8. The pVTt method hydrogen flow calibration device according to any one of claims 1 to 7, characterized in that: The gas storage pressure stabilizing module comprises a pressure controller (7) and a gas storage pressure stabilizing tank (8); the heat exchange module (6), the pressure controller (7) and the gas storage pressure stabilizing tank (8) are connected in sequence; and the gas storage pressure stabilizing tank (8) is connected to the hydrogen module to be tested in an on-off manner.

9. The pVTt method hydrogen flow calibration device according to any one of claims 1 to 7, characterized in that: The hydrogen module to be inspected comprises a temperature transmitter (13) and a first inspected group and a second inspected group connected in parallel. Both ends of the first inspected group and the second inspected group are connected to the gas storage and pressure stabilizing module and the measuring tank (21) in a switchable manner. The temperature transmitter (13) is arranged at the parallel inlet end of the first inspected group and the second inspected group. The first inspected group comprises a sonic nozzle to be inspected (16) and a differential pressure transmitter (17) connected in parallel to the sonic nozzle (16). The second inspected group comprises a flow controller (11), a pressure transmitter (14) and a flow meter to be inspected (12) arranged in sequence.

10. The pVTt method hydrogen flow calibration device according to any one of claims 1 to 7, characterized in that: The measuring module further comprises a second vacuum pump (26) arranged on a connecting pipeline between the measuring tank (21) and the exhaust pipeline (47); the measuring assembly comprises a timer (22), a thermometer (23) and a pressure gauge (24); the timer (22) is used to measure the time taken for hydrogen to flow into or out of the measuring tank (21); the thermometer (23) and the pressure gauge (24) are used to measure the temperature and pressure in the measuring tank (21), respectively.

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