Gas leakage rate testing device and method for non-metallic hydrogen transmission pipeline

Abstract

The present invention relates to the field of gas energy transmission and leakage testing, and in particular to a gas leakage rate testing device and method for non-metallic hydrogen transmission pipelines. The gas leakage rate testing device includes a detection member formed with a detection cavity suitable for placing the pipeline to be tested, and a sealed test cavity is formed after the pipeline to be tested is placed in the detection cavity; the calibration cavity is selectively connected to the test cavity; the first gas filling component is selectively connected to the calibration cavity, so as to be suitable for injecting a gas of a first set pressure into the calibration cavity; the measuring unit is configured to measure the pressure and temperature in the calibration cavity and the pressure and temperature in the test cavity, and calculate the volume of the test cavity; the leakage rate testing unit, the leakage rate testing unit is configured to obtain the pressure change value of the test cavity within a preset time interval, and calculate the gas leakage rate of the pipeline to be tested. The present invention solves the technical problem of inaccurate gas leakage rate testing caused by difficult or inaccurate measurement of the test cavity volume.

Description

Technical Field

[0001] The invention relates to the field of gas energy transmission and leakage testing, and in particular to a gas leakage rate testing device and method for a non-metallic hydrogen transmission pipeline. Background Art

[0002] Due to the special physical and chemical properties of hydrogen, traditional pipeline construction must be low-carbon and high-strength seamless steel pipes, which have high material costs and are difficult to construct. As a result, the construction cost per kilometer is approximately 4.5 to 6 million yuan; at the same time, in long-term use, the problem of hydrogen embrittlement failure of pipeline materials needs to be considered. The higher the hydrogen pressure and the higher the strength of the material, the more obvious the hydrogen embrittlement and hydrogen-induced cracking phenomena are, which will inevitably lead to pipeline damage during use. Therefore, using non-metallic materials to build long-distance hydrogen pipelines is a way to solve the high cost of hydrogen pipeline construction materials.

[0003] However, non-metallic pipelines have the problem of hydrogen leakage. Hydrogen permeation will lead to the deterioration of the mechanical properties of non-metallic pipelines, and will also cause hydrogen leakage, affecting safety and transportation efficiency. This is also the biggest factor limiting the application of non-metallic materials in the field of hydrogen transportation. In practical applications, non-metallic hydrogen pipelines can be used for the transportation of pure hydrogen or hydrogen-blended gas, such as hydrogen-blended natural gas. Therefore, it is very necessary to carry out leakage rate tests on hydrogen and other gases in non-metallic hydrogen pipelines and develop gas leakage rate equipment for non-metallic hydrogen pipelines.

[0004] The applicant's prior patent ZL202210747875.2, entitled "A non-metallic pipe hydrogen permeability testing device and method", records a non-metallic pipe hydrogen permeability testing device and method, which has good testing efficiency and calculation result accuracy for non-metallic pipes. However, in actual applications, it was found that the device and method still have at least the following shortcomings: First, usually only pipes of specific shapes and outer diameters can be tested, and the outer diameter of the pipe and the inner diameter of the test tube need to be precisely matched, and cannot be used for testing pipes of various specifications. Second, in the gas leakage rate test of non-metallic pipelines, the size of the test chamber volume has a great influence on the test accuracy, but it is difficult to accurately measure the test chamber volume. The difficulties in accurate measurement are mainly reflected in the following aspects:

[0005] 1) The test pipe needs to be sealed at both ends during the leakage test. The seal is an irregularly shaped workpiece, and its volume itself is difficult to measure accurately. In addition, the coordination between the seal and the test pipe must be considered, making the volume measurement even more difficult.

[0006] 2) Annular and axial reinforcements are required outside the test pipe. Although their volumes are fixed, the connections between them and the test pipe need to be considered, which are often a lot of bolts and nuts, and their volumes are difficult to measure accurately.

[0007] 3) When high-pressure hydrogen is filled into the test pipe, the pipe will inevitably deform. This deformation may occur locally or as a whole. The volume change caused by the pipe deformation is also difficult to measure;

[0008] 4) The test chamber needs to reserve a lot of sensor interfaces, valve interfaces, etc., and these volume measurements are often difficult.

[0009] When conducting gas leakage rate tests on non-metallic pipelines, it is also necessary to explore the impact of air pressure changes inside the pipeline on pipeline deformation. Therefore, it is necessary to measure pipeline deformation. However, in the vacuum environment of the test chamber, the use of displacement sensors, strain gauges, etc. to measure pipeline deformation is often limited, and the accuracy of the measured pipeline deformation is poor. Summary of the invention

[0010] The present invention provides a gas leakage rate testing device and method for a non-metallic hydrogen transmission pipeline, so as to solve the technical problem that the gas leakage rate testing is inaccurate due to the difficulty or inaccuracy of volume measurement.

[0011] In order to solve the above technical problems, an embodiment of the present invention provides a gas leakage rate testing device for a non-metallic hydrogen transmission pipeline, comprising: a detection member, the detection member is formed with a detection cavity suitable for placing the pipeline to be tested, wherein a sealed test cavity is formed after the pipeline to be tested is placed in the detection cavity; a calibration cavity, the calibration cavity is selectively connected to the test cavity; a first gas filling component, the first gas filling component is selectively connected to the calibration cavity, so as to be suitable for injecting a gas of a first set pressure into the calibration cavity; a second gas filling component, the second gas filling component is selectively connected to the pipeline to be tested, so as to be suitable for injecting a gas of a second set pressure into the pipeline to be tested; a measuring unit, which is configured to measure the pressure in the calibration cavity and temperature as well as the pressure and temperature in the test chamber, and the volume of the test chamber is calculated based on the first pressure and the first temperature in the calibration chamber before the calibration chamber is connected to the test chamber, the second pressure and the second temperature in the test chamber, and the third pressure and the third temperature in the test chamber after the calibration chamber is connected to the test chamber and the leakage of the pipeline to be tested is balanced; a leakage rate testing unit, wherein the leakage rate testing unit is configured to obtain a pressure change value of the test chamber within a preset time interval, and calculate the gas leakage rate of the pipeline to be tested based on the preset time interval, the pressure change value, the current temperature in the test chamber and the volume of the test chamber after the leakage of the pipeline to be tested is balanced.

[0012] As a preferred embodiment, the leakage rate testing unit calculates the gas leakage rate of the pipeline to be tested based on the first formula:

[0013]

[0014] Wherein, J represents the gas leakage rate of the non-metallic hydrogen transmission pipeline, is the pressure change value, is the preset time interval, V2 is the volume of the test chamber, R is the molar gas constant, T is the current temperature in the test chamber, and L is the length of the pipeline to be tested.

[0015] As a preferred embodiment, the measuring unit comprises: a first temperature sensor and a first pressure sensor arranged corresponding to the calibration chamber; and a second temperature sensor and a second pressure sensor arranged corresponding to the test chamber.

[0016] As a preferred embodiment, the measuring unit calculates the volume of the test chamber based on a second formula:

[0017]

[0018] Among them, V1 represents the volume of the calibration chamber, V2 represents the volume of the test chamber, P1 represents the first pressure, P2 represents the second pressure, P3 represents the third pressure, T1 represents the first temperature, T2 represents the second temperature, and T3 represents the third temperature.

[0019] As a preferred embodiment, the measuring unit also includes: a first temperature control component, the first temperature control component corresponds to the calibration chamber setting; and a second temperature control component, the second temperature control component corresponds to the test chamber setting, the first temperature control component and the second temperature control component are used to adjust the second temperature to be consistent with the first temperature.

[0020] As a preferred embodiment, when the first temperature and the second temperature are consistent, the measuring unit calculates the volume of the test chamber based on a third formula:

[0021]

[0022] Among them, V1 represents the volume of the calibration chamber, V2 represents the volume of the test chamber, P1 represents the first pressure, P2 represents the second pressure, and P3 represents the third pressure.

[0023] As a preferred embodiment, the sum of the internal volumes of the calibration chamber and the pipeline connected thereto is greater than or equal to 1 / 10 of the sum of the internal volumes of the test chamber and the pipeline connected thereto, and the sum of the internal volumes of the calibration chamber and the pipeline connected thereto is less than or equal to twice the sum of the internal volumes of the test chamber and the pipeline connected thereto.

[0024] As a preferred embodiment, the pipeline to be tested includes a non-metallic pipeline and a connecting joint connected to the non-metallic pipeline, and the connecting joint is any one of a hot-melt joint, an electric-melt joint, and a mechanical joint.

[0025] As a preferred embodiment, the gas includes at least one of hydrogen, helium, natural gas, nitrogen, methane, gas and carbon dioxide.

[0026] The present invention also provides a gas leakage rate testing method for a non-metallic hydrogen transmission pipeline, which is applied to the gas leakage rate testing device described in any of the above embodiments, and the method comprises: after the pipeline to be tested is placed in the detection cavity to form a sealed test cavity, the test cavity is evacuated; the air in the pipeline to be tested is exhausted, and a gas of a second set pressure is injected into the pipeline to be tested; when the gas leakage in the pipeline to be tested reaches equilibrium, the pressure change value of the test cavity within a preset time interval is obtained, and the gas leakage rate of the pipeline to be tested is calculated based on the preset time interval, the pressure change value, the volume of the test cavity, and the current temperature in the test cavity.

[0027] The present invention also provides a method for testing the volume expansion of a non-metallic hydrogen transmission pipeline, which is applied to the gas leakage rate testing device described in any of the above embodiments. The method comprises: before performing the gas leakage rate test, the measuring unit calculates the first volume of the test chamber based on the second formula:

[0028]

[0029] Wherein, V1 represents the volume of the calibration chamber, V2 represents the volume of the test chamber, P1 represents the first pressure, P2 represents the second pressure, P3 represents the third pressure, T1 represents the first temperature, T2 represents the second temperature, and T3 represents the third temperature; perform a non-metallic pipeline gas leakage rate test; after the above test is completed, the measuring unit calculates the second volume of the test chamber based on the second formula, and calculates the volume expansion of the pipeline to be tested based on the difference between the first volume and the second volume. Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0030] 1. The present invention adds a calibration chamber and measures the pressure and temperature changes in the test chamber to accurately calibrate the volume of the test chamber. This structure can be applied to the volume measurement of test chambers of any shape. It avoids the problem of difficult volume measurement due to the complex structure of pipe joints and connecting pipes, thereby achieving a set of equipment to measure the internal test chamber volume after different structural configurations and different shapes of the tested pipes are placed in the detection part.

[0031] 2. The detection component of the present invention can accommodate pipelines to be tested and connecting pipelines of different shapes and specifications. By accurately measuring the volume change of the test cavity, the accuracy of the gas leakage rate test data of the non-metallic hydrogen pipeline is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : is a structural schematic diagram of a non-metallic hydrogen pipeline gas leakage rate testing device of the present invention;

[0033] Figure 2 : It is a structural schematic diagram of the calibration chamber in the gas leakage rate testing device for non-metallic hydrogen pipeline of the present invention;

[0034] Figure 3 : is a schematic diagram of the internal structure of the detection component of the non-metallic hydrogen pipeline gas leakage rate testing device of the present invention;

[0035] Figure 4 : is a schematic diagram of the calibration steps of an embodiment of the calibration method of the volume measuring device of the present invention.

[0036] The reference numerals of the drawings in the specification are as follows:

[0037] 1-test piece; 11-test chamber; 12-second pressure sensor; 13-second temperature sensor; 14-second temperature control assembly; 21-calibration chamber; 211-first pressure sensor; 212-first temperature sensor; 221-third pipeline; 222-first high-pressure gas source; 223-second valve; 23-first temperature control assembly; 31-pipeline to be tested; 32-support seat; 33-seal; 34-pad; 4-first pipeline; 5-second pipeline; 6-first valve; 71-third valve; 72-first vacuum pump; 73-fourth valve; 74-second vacuum pump; 75-exhaust gas treatment system; 81-second high-pressure gas source. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] An embodiment of the present invention provides a gas leakage rate testing device for a non-metallic hydrogen pipeline, which includes a volume measuring device and a leakage rate testing unit, wherein the volume measuring device includes a detection component 1, a calibration chamber 21, a first gas filling component, a second gas filling component and a measuring unit.

[0040] Please refer to Figures 1 to 3 The detection member 1 is formed with a detection cavity suitable for placing the pipe 31 to be tested, wherein a sealed test cavity 11 is formed after the pipe 31 to be tested is placed in the detection cavity, that is, the detection member 1 has a hollow structure inside, and the unoccupied detection cavity inside the detection member 1 forms the test cavity 11. The test cavity 11 formed in the detection member 1 can be of any shape, that is, the pipe 31 to be tested can be of any shape, and further the unoccupied test cavity 11 in the detection cavity can be of any shape.

[0041] The calibration chamber 21 is selectively connected to the test chamber 11; the first gas filling component is selectively connected to the calibration chamber 21, so as to be suitable for injecting gas of a first set pressure into the calibration chamber. In other words, the calibration chamber 21 is a hollow structure with a containing chamber for containing gas. When the calibration chamber 21 is connected to the first gas filling component, the first gas filling component inflates the calibration chamber 21; when the calibration chamber 21 is connected to the test chamber 11, the gas in the calibration chamber 21 and the test chamber 11 are mixed.

[0042] The measuring unit is configured to measure the pressure and temperature in the calibration chamber 21 and the pressure and temperature in the test chamber 11, so as to calculate the volume of the test chamber 11 based on the first pressure and the first temperature in the calibration chamber 21 before the calibration chamber 21 is connected to the test chamber 11, the second pressure and the second temperature in the test chamber 11, and the third pressure and the third temperature in the test chamber 11 after the calibration chamber 21 is connected to the test chamber 11. It should be understood that the measuring unit can measure the third pressure and the third temperature in the test chamber 11 after the calibration chamber 21 is connected to the test chamber 11 before or after the gas leakage rate test is performed on the pipeline 31 to be tested.

[0043] As a preferred embodiment, the measuring unit includes: a first temperature sensor 212 and a first pressure sensor 211 arranged corresponding to the calibration chamber 21, the first temperature sensor 212 is used to measure the temperature in the calibration chamber 21, and the first pressure sensor 211 is used to measure the pressure in the calibration chamber 21; a second temperature sensor 13 and a second pressure sensor 12 are arranged corresponding to the test chamber 11, the second temperature sensor 13 is used to measure the temperature in the test chamber 11, and the second pressure sensor 12 is used to measure the pressure in the test chamber 11. The first temperature sensor 212 and the second temperature sensor 13 can be thermocouple temperature sensors, resistance temperature sensors, infrared temperature sensors, etc., as long as they can measure the temperature of the calibration chamber 21 and the test chamber 11. The measuring unit can also measure the pressure in the calibration chamber 21 and the pressure in the test chamber 11 through instruments such as pressure gauges that can measure the pressure of the calibration chamber 21 and the test chamber 11.

[0044] In the present invention, the internal structure of the detection member 1 is a hollow structure, which is a detection cavity, and the test cavity is formed into a test cavity 11 after the test pipe 31 is placed in the detection cavity. The measuring unit is used to measure the pressure and temperature 3 in the test cavity 11 and the calibration cavity. The calibration cavity 21 is selectively connected to the first gas filling component, and the calibration cavity 21 is selectively connected to the test cavity 11. The first gas filling component is selectively connected to the calibration cavity 21 through a pipeline, and is used to inflate the calibration cavity 21. When the calibration chamber 21 is needed to calibrate the volume of the test chamber 11, the first gas filling component is connected to the calibration chamber 21, and the calibration chamber 21 is in a closed state with the test chamber 11 at this time. The first gas filling component fills the calibration chamber 21 with gas to a first preset pressure, closes the connection between the first gas filling component and the calibration chamber 21, records the first pressure and the first temperature in the calibration chamber 21, and records the second pressure and the second temperature in the test chamber; connects the calibration chamber 21 and the test chamber 11, mixes the gas in the calibration chamber 21 with the gas in the test chamber 11, records the third temperature and the third pressure of the test chamber 11, and then calculates the volume in the test chamber 11.

[0045] The present invention accurately obtains the volume of the calibration chamber 21 by adding a calibration chamber 21, and then measures the pressure and temperature changes in the test chamber 11 to accurately calibrate the volume of the test chamber 11. The structure can be applied to the volume measurement of the test chamber 11 of any shape, that is, the detection part of the volume measurement device can be applied to any shape of the pipeline 31 to be tested or the connecting joint. The difficulty of measuring the volume due to complex structure and coordination between structures is avoided, so that a set of equipment can be used to measure the volume of the internal test chamber 11 after placing the pipeline 31 to be tested or the connecting joint of different structural configurations and shapes in the detection part.

[0046] Specifically, the test chamber 11 is connected to the calibration chamber 21 through the first pipeline 4 and the second pipeline 5. The first valve 6 is provided at the connection between the first pipeline 4 and the second pipeline 5. The first pipeline 4 is connected to the test chamber 11, and the second pipeline 5 is connected to the calibration chamber 21. When the calibration chamber 21 is needed to calibrate the volume of the test chamber 11, the first gas filling component is connected to the calibration chamber 21, and the calibration chamber 21 is in a closed state with the detection element 1 at this time. The first gas filling component fills the calibration chamber 21 with gas to the first preset pressure, closes the connection between the first gas filling component and the calibration chamber 21, records the first pressure and the first temperature in the calibration chamber 21, and records the second pressure and the second temperature in the test chamber; opens the first valve 6 to connect the calibration chamber 21 with the test chamber 11, and the gas in the calibration chamber 21 is mixed with the gas in the test chamber 11 through the second pipeline 5 and the first pipeline 4, and the third temperature and the third pressure of the test chamber 11 are recorded, and then the volume in the test chamber 11 is calculated.

[0047] Furthermore, the first gas filling assembly includes a third pipeline 221 and a first high-pressure gas source 222. The third pipeline 221 is provided between the calibration chamber and the first high-pressure gas source 222, and is used to connect the third pipeline 221 and the first high-pressure gas source 222. A second valve 223 is provided on the third pipeline 221. The portion of the third pipeline between the calibration chamber 21 and the second valve 223 is always in a connected state with the calibration chamber 21, and the volume of this portion of the pipeline should be calculated when calculating the volume of the calibration chamber 21. The calibration chamber 21 is also always in a connected state with the second pipeline 5. When calculating the volume of the calibration chamber 21, the volume of the second pipeline 5 should also be calculated. Therefore, the volume of the calibration chamber 21 is equal to the sum of the volumes of the calibration chamber 21 and the second pipeline 5 connected to the calibration chamber 21, and the third pipeline 221 between the calibration chamber 21 and the second valve 223. When the calibration chamber 21 is needed to calibrate the volume of the test chamber 11, the second valve 223 is opened, the first high-pressure gas source 222 is connected to the calibration chamber 21 through the third pipeline 221, the calibration chamber 21 is now in a closed state with the test chamber 11, the first high-pressure gas source 222 adds gas to the calibration chamber 21 to the first set pressure, the second valve 223 is closed, the connection between the first high-pressure gas source 222 and the calibration chamber 21 is closed, the first pressure and the first temperature in the calibration chamber 21 are recorded, and the second pressure and the second temperature in the test chamber 11 are recorded. The first valve 6 is opened to connect the calibration chamber 21 and the test chamber 11, the gas in the calibration chamber 21 is mixed into the test chamber 11 through the second pipeline 5 and the first pipeline 4, the third temperature and the third pressure of the test chamber 22 are recorded, and the volume in the test chamber 11 is calculated. The volume measurement process of the test chamber 11 can be performed before or after the gas leakage rate test of the pipeline 31 to be tested.

[0048] It should be understood that the detection member 1, the calibration chamber 21, all connecting pipes, and the control valve materials in the present invention are all hydrogen-blocking materials, such as austenitic stainless steel, low alloy steel, precipitation-strengthened austenitic alloy, and aluminum alloy materials.

[0049] As a preferred embodiment, the volume measuring device also includes a second gas filling component, which is selectively connected to the pipe to be tested 31 so as to be suitable for injecting gas of a second set pressure into the pipe to be tested 31, wherein the measuring unit is also configured to calculate the volume of the test chamber 11 based on the first pressure and the first temperature in the calibration chamber 21 before the calibration chamber 21 is connected with the test chamber 11, the second pressure and the second temperature in the test chamber 11, and the third pressure and the third temperature in the test chamber 11 after the calibration chamber 21 is connected with the test chamber 11, after the gas of the second set pressure is injected into the pipe to be tested 31.

[0050] Specifically, the second gas filling component is selectively connected to the pipe to be tested 31, and is used to inflate the pipe to be tested 31. The interior of the detection member 1 is a hollow structure, and the pipe to be tested 31 can be placed in the hollow structure inside the detection member 1, so that the interior of the detection member 1 also has an unoccupied cavity structure, and the cavity structure forms a test cavity 11. When it is necessary to test the gas leakage rate of the pipe to be tested 31 and / or measure the volume in the test cavity, the two ends of the pipe to be tested 31 are sealed and placed in the detection member 1 and the detection member 1 is sealed. At this time, the test cavity 11 is formed in the detection member 1, and the pipe to be tested 31 is inflated by the second gas filling component, and inflated to the second set pressure. The volume of the test cavity 11 is calculated based on the first pressure and the first temperature in the calibration cavity 21 before the calibration cavity 21 is connected to the test cavity 11, the second pressure and the second temperature in the test cavity, and the third pressure and the third temperature in the test cavity 11 after the calibration cavity 21 is connected to the test cavity 11. It should be understood that after the second gas filling assembly inflates the test pipe 31, the test pipe 31 is first subjected to a gas leakage rate test. After the test pipe 31 is subjected to the gas leakage rate test, the volume in the test chamber 11 is calibrated by the measuring unit. The volume in the current test chamber 11 is calculated by measuring the first temperature and the first pressure in the calibration chamber before the test chamber 11 is connected to the calibration chamber 21, the second temperature and the second pressure in the test chamber; and the third pressure and the third temperature in the test chamber 11 after the test chamber 11 is connected to the calibration chamber 21. Since the test chamber 11 has been subjected to the gas leakage rate test at this time, the test pipe 31 has been expanded due to the internal gas pressure. Therefore, the calculated volume in the test chamber 11 takes into account the volume after the expansion and deformation of the test pipe 31, which solves the problem of volume measurement error of the sealing test chamber 11 caused by the expansion and deformation during the test of the test pipe 31, thereby achieving more accurate data for the gas leakage rate test of the test pipe 31.

[0051] It should be understood that after both ends of the pipe to be tested 31 are sealed, the pipe to be tested 31 can be inflated through the second gas filling component, and then the pipe to be tested 31 is placed in the detection piece 1, and then the detection piece 1 is sealed; or, after both ends of the pipe to be tested 31 are sealed, the pipe to be tested 31 is placed in the detection piece 1, and the detection piece 1 is sealed, and then the pipe to be tested 31 is inflated through the second gas filling component.

[0052] After sealing both ends of the pipe 31 to be tested and placing it in the detection piece 1, the detection piece 1 is sealed. Since the pipe 31 to be tested occupies the volume in the detection piece 1 after being placed in the detection piece 1, the unoccupied part of the space in the detection piece 1 is the test chamber 11. After the gas leakage in the pipe 31 to be tested is balanced, the volume and pressure change of the test chamber 11 can be measured to obtain the gas leakage rate of the pipe 31 to be tested. The volume of the test chamber 11 is calibrated by a volume measuring device, and the volume of the test chamber 11 is measured according to the method described in this article based on the ideal gas state equation. The measurement of the volume of the test chamber 11 is not limited by structure and shape, that is, any shape and any structure can be placed in the detection piece 1 in any way to form any style of test chamber 11, and the volume of the test chamber 11 can be measured according to the volume calibration method described in this article. During the gas leakage rate test of the pipeline 31 to be tested, there is no need to consider the shape and structure of the pipeline, nor the shape and structure of other structures connected to the pipeline. The volume measurement method of this article can be used to calibrate the volume of the test chamber 11 and then obtain the gas leakage rate of the pipeline 31 to be tested.

[0053] As a preferred embodiment, the second gas filling assembly includes a second high-pressure gas source 81, a pipeline connecting the second high-pressure gas source 81 and the pipeline to be tested 31, and a valve is also provided on the pipeline. When the valve is opened, the second high-pressure gas source 81 fills the pipeline to be tested 31 with gas; when the valve is closed, the second high-pressure gas source 81 and the pipeline to be tested 31 are closed, and the second high-pressure gas source 81 stops filling the pipeline to be tested 31 with gas.

[0054] As a preferred embodiment, the pipeline to be tested includes a non-metallic pipeline and a connecting joint connected to the non-metallic pipeline, and the connecting joint is any one of a hot-melt joint, an electric-melt joint, and a mechanical joint. That is to say, the pipeline to be tested 31 can be a non-metallic pipeline, or it can be a non-metallic pipeline and a connecting joint connected to the non-metallic pipeline as a whole, wherein the connecting joint can be any one of a hot-melt joint, an electric-melt joint, a mechanical joint, etc., for measuring the gas permeability and gas leakage of the non-metallic pipeline joint. It should be understood that if the pipeline to be tested 31 needs to be inflated after being placed in the detection member 1, then the pipeline connecting the second high-pressure gas source 81 and the pipeline to be tested 31 should be connected to the second high-pressure gas source 81 at one end, and the other end should pass through the side wall of the detection member 1 to enter the interior of the detection member 1 and connect to the pipeline to be tested 31.

[0055] As a preferred embodiment, in the gas leakage rate test of the non-metallic hydrogen pipeline, the test gas used includes at least one of hydrogen, helium, natural gas, nitrogen, methane, gas and carbon dioxide, that is, the test gas can be one of hydrogen, helium, natural gas, nitrogen, methane, gas or carbon dioxide, or a mixture of multiple gases, such as hydrogen-mixed natural gas. It should be understood that the non-metallic hydrogen pipeline can be used not only for the transportation of pure hydrogen, but also for the transportation of hydrogen-mixed mixed gases, such as hydrogen-mixed natural gas. Therefore, in order to explore the leakage rate of hydrogen-mixed mixed gases, it is necessary to carry out leakage tests on non-metallic hydrogen pipelines for gases such as hydrogen, helium, natural gas, nitrogen, methane, gas, carbon dioxide and their mixed gases.

[0056] As a preferred embodiment, the volume measurement device further includes a first temperature control component 23, which is arranged corresponding to the calibration chamber 21 to adjust the first temperature to be consistent with the second temperature. The calibration chamber 21 is equipped with a first temperature control component 23, which can adjust the gas temperature inside the calibration chamber 21. When the temperature in the calibration chamber 21 is different from that in the test chamber 11, the sensor transmits a signal to the controller, and the controller issues a corresponding instruction according to the temperature difference between the calibration chamber 21 and the test chamber 11. The actuator executes the command issued by the controller to adjust the temperature in the calibration chamber 21, so that the temperature in the calibration chamber 21 is the same as that in the test chamber 11, thereby facilitating the volume calculation in the test chamber 11.

[0057] As a preferred embodiment, the volume measurement device further includes a second temperature control component 14, which is arranged corresponding to the test chamber 11 to adjust the second temperature to be consistent with the first temperature. The second temperature control component 14 arranged on the detection member 1 corresponding to the test chamber 11 can adjust the gas temperature in the test chamber 11. When the temperature in the calibration chamber 21 is different from that in the test chamber 11, the sensor transmits a signal to the controller, and the controller issues a corresponding instruction according to the temperature difference between the calibration chamber 21 and the test chamber 11. The actuator executes the command issued by the controller to adjust the temperature in the test chamber 11, so that the temperature in the test chamber 11 is the same as that in the calibration chamber 21, thereby facilitating the volume calculation in the test chamber 11.

[0058] It should be understood that the present invention can only set the first temperature control component 23 in the calibration chamber 21 to adjust the temperature in the calibration chamber 21 so that the temperature in the calibration chamber 21 is consistent with that in the test chamber 11, and no temperature control component is set in the test chamber 11; or the second temperature control component 14 can be set in the test chamber 11 to adjust the temperature in the test chamber 11 so that the temperature in the test chamber 11 is consistent with that in the calibration chamber 21, and no temperature control component is set in the calibration chamber 21; preferably, the calibration chamber 21 is correspondingly provided with the first temperature control component 23, and the test chamber 11 is also correspondingly provided with the second temperature control component 14, and the temperatures in the test chamber 11 and the calibration chamber 21 are adjusted at the same time to ensure that the temperatures in the test chamber 11 and the calibration chamber 21 are consistent, that is, the first temperature, the second temperature, and the third temperature are kept the same. That is to say, the first temperature control component 23 and / or the second temperature control component 14 are set to keep the temperatures in the test chamber 11 and the calibration chamber 21 the same when the volume of the test chamber 11 is measured, so as to facilitate the measurement of the volume in the test chamber 11. The specific configuration of the first temperature control component 23 and the second temperature control component 14 corresponding to the calibration chamber 21 and the test chamber 11 may be determined according to specific circumstances.

[0059] In a possible embodiment, the first temperature control component 23 may include a plurality of temperature sensors disposed in the calibration chamber 21, so that the temperature of each area in the calibration chamber 21 can be controlled, ensuring that the temperature of each area in the calibration chamber 21 is the same. The second temperature control component 14 includes a plurality of temperature sensors disposed on the inner wall of the detection element 1, so that the temperature of each area in the test chamber 11 can be controlled, ensuring that the temperature of each area in the test chamber 11 is the same.

[0060] Specifically, the measuring unit calculates the volume of the test chamber based on the second formula:

[0061]

[0062] Among them, V1 represents the calibration chamber volume, V2 represents the test chamber volume, P1 represents the first pressure, P2 represents the second pressure, P3 represents the third pressure, T1 represents the first temperature, T2 represents the second temperature, and T3 represents the third temperature. In actual measurement, considering the influence of the internal volume of the pipeline, the calibration chamber volume represented by V1 here should be understood as the sum of the calibration chamber and the internal volume of the pipeline connected thereto. Similarly, the test chamber volume represented by V2 should be understood as the sum of the internal volume of the test chamber and the internal volume of the pipeline connected thereto.

[0063] Specifically, refer to Figure 4 The volume measurement method of the volume measurement device comprises the following steps:

[0064] Step S41: Open the second valve, inflate the calibration chamber to the first set pressure through the first high-pressure gas source of the first gas filling assembly, and record the first pressure P1 and the first temperature T1 in the calibration chamber, and close the second valve; at this time, the first valve between the test chamber and the calibration chamber is in a closed state, the test chamber and the calibration chamber are not connected, and the second pressure P2 and the second temperature T2 of the test chamber when the calibration chamber and the test chamber are not connected are recorded. Step S42: Open the first valve between the calibration chamber and the test chamber, connect the calibration chamber and the test chamber, so that the gases in the calibration chamber and the test chamber are mixed, and after the gases in the calibration chamber and the test chamber are evenly mixed and reach a stable state, record the third pressure P3 and the third temperature T3 of the test chamber.

[0065] Step S43: Calculate the volume of the test chamber according to the following second formula:

[0066]

[0067] Where V1 represents the calibration chamber volume, in m 3 ; V2 represents the volume of the test chamber, in m 3 ; P1 represents the first pressure in the calibration chamber before the calibration chamber and the test chamber are connected, in units of Pa; P2 represents the second pressure in the test chamber before the calibration chamber and the test chamber are connected, in units of Pa; P3 represents the third pressure in the test chamber after the calibration chamber and the test chamber are connected, in units of Pa; T1 represents the first temperature in the calibration chamber before the calibration chamber and the test chamber are connected, in units of K; T2 represents the second temperature of the test chamber before the calibration chamber and the test chamber are connected, in units of K; T3 represents the third temperature of the test chamber after the calibration chamber and the test chamber are connected, in units of K. In actual measurement, the influence of the internal volume of the pipeline is taken into account. The calibration chamber volume represented by V1 here should be understood as the sum of the internal volumes of the calibration chamber and the pipeline connected thereto. Similarly, the test chamber volume represented by V2 should be understood as the sum of the internal volumes of the test chamber and the pipeline connected thereto. Read the first pressure P1 of the first pressure sensor and the first temperature T1 of the calibration chamber. According to the ideal gas state equation, we have:

[0068]

[0069] Where P1 represents the first pressure in the calibration chamber before the calibration chamber and the test chamber are connected, in Pa; V1 represents the volume of the calibration chamber, in m 3 , N1 represents the number of moles of gas in the calibration chamber before the calibration chamber and the test chamber are connected, in mol; R represents the gas molar constant, which is 8.31 J / mol / K; T1 represents the first temperature in the calibration chamber before the calibration chamber and the test chamber are connected, in K.

[0070] Read the second pressure sensor reading in the test chamber, the second pressure P2, and the second temperature sensor reading, the second temperature T2. Similarly,

[0071]

[0072] Where P2 represents the second pressure in the test chamber before the calibration chamber and the test chamber are connected, in Pa; V2 represents the volume of the test chamber, in m 3 , N2 represents the number of moles of gas in the test chamber before the calibration chamber and the test chamber are connected, in mol; T2 represents the second temperature in the test chamber before the calibration chamber and the test chamber are connected, in K.

[0073] Open the first valve, the gas in the test chamber and the calibration chamber will mix quickly, wait until the pressure and temperature readings are stable, read the third pressure P3 of the second pressure sensor and the third temperature T3 of the second temperature sensor in the test chamber.

[0074]

[0075] Wherein, P3 represents the third pressure in the test chamber after the calibration chamber and the test chamber are connected, and the unit is Pa; T3 represents the third temperature in the test chamber after the calibration chamber and the test chamber are connected, and the unit is K.

[0076] According to the above three formulas, the second formula can be obtained, and the volume V2 of the test chamber can be calculated according to the second formula:

[0077]

[0078] In the calibration method of the volume measurement device of the present invention, the first pressure sensor on the calibration chamber measures the pressure inside the calibration chamber and the pipeline connected thereto; the second pressure sensor on the test chamber measures the pressure inside the test chamber and the pipeline connected thereto. The first temperature sensor on the calibration chamber measures the temperature inside the calibration chamber and the pipeline connected thereto; the second temperature sensor on the test chamber measures the temperature inside the test chamber and the pipeline connected thereto.

[0079] A first temperature control component can be installed inside the calibration chamber, and a second temperature control component can be installed inside the detection component, so that the temperature of the calibration chamber can be controlled to be consistent with the temperature of the test chamber, maintaining a constant temperature environment throughout the test process, that is, T1=T2=T3 mentioned above.

[0080] Therefore, the third formula can be obtained, and the volume V2 of the test chamber can be calculated according to the third formula:

[0081]

[0082] In this embodiment, when the calibration chamber is used to calibrate the volume of the test chamber, the first gas pressure P1 in the calibration chamber is not less than 2 times the second gas pressure P2 in the test chamber, and the first gas pressure P1 in the calibration chamber is not greater than 10000 times the second gas pressure P2 in the test chamber. It is ensured that after the calibration chamber is connected to the test chamber, the pressure change in the test chamber can be clearly sensed and accurately displayed by the second pressure sensor.

[0083] As a preferred embodiment, the sum of the internal volumes of the calibration chamber 21 and the pipeline connected thereto is greater than or equal to 1 / 10 of the sum of the internal volumes of the test chamber 11 and the pipeline connected thereto, and the sum of the internal volumes of the calibration chamber 21 and the pipeline connected thereto is less than or equal to twice the sum of the internal volumes of the test chamber 11 and the pipeline connected thereto.

[0084] In this embodiment, in order to accurately calibrate the volume of the test chamber 11, the volume of the calibration chamber 21 and the pipeline connected thereto should not be too small, otherwise the pressure change of the test chamber 11 will be too small after the calibration chamber 21 is connected to the test chamber 11, and the value change of the second pressure sensor 12 will be too small, which will increase the volume calculation error of the test chamber 11. Therefore, the sum of the volumes of the calibration chamber 21 and the pipeline connected thereto should not be less than 1 / 10 of the estimated volume of the test chamber 11 and the pipeline connected thereto. The present invention avoids the problem of excessive measurement error caused by too small volume of the calibration chamber 21 by limiting the volume of the calibration chamber 21, and improves the accuracy of the gas leakage rate test result of the pipeline 31 to be tested. And the sum of the volumes of the calibration chamber 21 and the pipeline connected thereto should not be greater than twice the estimated volume of the test chamber 11 and the pipeline connected thereto, which can avoid the increase in equipment processing difficulty and cost caused by the excessive design of the calibration chamber 21 volume.

[0085] The gas leakage rate testing device for a non-metallic hydrogen pipeline provided by the present invention comprises a volume measuring device as described in any of the above embodiments, and a leakage rate testing unit. The volume measuring device is configured to measure the volume of the test chamber 11; the leakage rate testing unit is configured to obtain the pressure change value of the test chamber 11 within a preset time interval when the second gas filling assembly in the volume measuring device injects gas of a second set pressure into the pipeline 31 to be tested, and the gas leakage in the pipeline 31 to be tested reaches equilibrium, and calculate the gas leakage rate of the pipeline 31 to be tested based on the preset time interval, the pressure change value, the volume of the test chamber 11, and the current temperature in the test chamber 11. It should be understood that when the gas leakage in the pipeline 31 to be tested reaches equilibrium, the slope of the pressure change curve in the test chamber 11 remains stable, so it can be judged whether the gas leakage in the pipeline 31 to be tested reaches equilibrium according to the change in the slope of the pressure change curve in the test chamber 11. When the gas leakage in the pipeline 31 to be tested reaches equilibrium, a time interval can be preset and the pressure change value within the preset time interval can be recorded. Among them, the volume of the test chamber 11 is measured by the above-mentioned volume measuring device. The volume of the test chamber 11 can be measured before the gas leakage rate test, or after the gas leakage of the pipeline 31 to be tested reaches equilibrium. The current temperature in the test chamber 11 refers to the temperature in the test chamber 11 after the gas leakage in the pipeline 31 to be tested reaches equilibrium. The measurement time of the second temperature and the third temperature may be different, and the value may also be different. However, if a second temperature control component 14 is provided in the test chamber 11 to keep the temperature in the test chamber 11 constant, then the current temperature in the test chamber 11 is the same as the second temperature and the third temperature.

[0086] When it is necessary to test the gas leakage rate of the pipeline 31 to be tested or to measure the volume in the test chamber 11, the two ends of the pipeline 31 to be tested are sealed and placed in the detection member 1 and the detection member 1 is sealed. At this time, the test chamber 11 is formed in the detection member 1, and the pipeline 31 to be tested is inflated by the second gas filling component and inflated to the second set pressure. After the gas leakage in the pipeline 31 to be tested reaches equilibrium, the pressure change value in the preset time interval in the test chamber 11 is obtained, and the gas leakage rate of the pipeline 31 to be tested is calculated based on the preset time interval, the pressure change value in the preset time interval, the volume of the test chamber 11, and the current temperature in the test chamber 11.

[0087] Specifically, the leakage rate testing unit calculates the gas leakage rate of the pipeline to be tested based on the first formula:

[0088]

[0089] Wherein, J represents the gas leakage rate, is the pressure change value, is the preset time interval, V2 is the volume of the test chamber, R is the molar gas constant, T is the current temperature in the test chamber, and L is the length of the pipeline to be tested.

[0090] As a preferred embodiment, the non-metallic hydrogen pipeline gas leakage rate test device also includes an exhaust system, which is selectively connected to the test chamber 11 and the pipeline to be tested 31, and the exhaust system is used to discharge the gas in the test chamber 11 and the pipeline to be tested 31. An exhaust pipe is provided between the exhaust system and the detection part 1 and the pipeline to be tested 31, and a valve is provided on the exhaust pipe. When it is necessary to exhaust the gas in the detection part 1 and the pipeline to be tested 31, the valves of the exhaust system, the test chamber 11 and the pipeline to be tested 31 are opened, and the vacuum pump is turned on to evacuate the gas in the detection part 1 and the pipeline to be tested 31.

[0091] Specifically, when the gas leakage rate test is performed on the pipe to be tested 31, the pipe to be tested 31 and the test chamber 11 are first evacuated through the exhaust system to ensure that the test chamber 11 and the pipe to be tested 31 are well sealed. Then, the second high-pressure gas source 81 and the pipe to be tested 31 are connected, and the pipe to be tested 31 is inflated through the second high-pressure gas source 81, and the pipe to be tested 31 is inflated to a second preset pressure. Then, a gas leakage rate test of the pipe to be tested 31 can be performed. It should be understood that the pipe to be tested 31 and the test chamber 11 can be evacuated at the same time, or the pipe to be tested 31 and the test chamber 11 can be evacuated separately, and the present invention is not limited to this.

[0092] The hollow structure of the detection member 1 in the present invention can accommodate the pipe 31 to be tested. When the pipe 31 to be tested is placed in the detection member 1, the gas leakage of the pipe 31 to be tested is measured by measuring the volume and pressure changes in the test cavity 11. It should be understood that the detection cavity in the detection member 1 can accommodate the pipe 31 to be tested of any shape, so that the test cavity 11 formed in the detection member 1 is of any shape. As long as the pipe 31 to be tested can be accommodated in the detection cavity of the detection member 1, the volume of the test cavity 11 can be measured, and then the gas leakage rate of the pipe 31 to be tested can be measured. In other words, the hollow structure in the detection member 1 can be applicable to the pipe 31 to be tested of any shape. When the pipe 31 to be tested is located in the detection member 1, the volume of the test cavity 11 is accurately calculated by measuring the pressure and temperature changes in the test cavity 11, and then the gas leakage rate of the pipe 31 to be tested is measured, thereby improving the accuracy of the test result of the pipeline gas leakage rate. It also avoids the difficulty of measuring volume due to complex structures and coordination between structures, so that not only can one set of equipment be used to measure non-metallic pipes of different diameters and shapes, but also gas leakage rate tests of various joint structures such as electric fusion joints, hot-melt joints or mechanical flange joints can be realized.

[0093] As a preferred embodiment, the exhaust system includes a first exhaust system and a second exhaust system, wherein the first exhaust system is selectively connected to the detection member 1, and the second exhaust system is selectively connected to the pipeline to be tested 31. The first exhaust system includes a third valve 71 and a first vacuum pump 72, wherein the third valve 71 is arranged between the first vacuum pump 72 and the detection member 1; the second exhaust system includes a fourth valve 73 and a second vacuum pump 74, wherein the fourth valve 73 is arranged between the second vacuum pump 74 and the pipeline to be tested 31, and the fourth valve 73 is located outside the detection member 1. Open the third valve 71, turn on the first vacuum pump 72, and evacuate the detection member 1 to ensure that the airtightness of the detection member 1 is good, and ensure that the subsequent measurement data is accurate; open the fourth valve 73, turn on the second vacuum pump 74, and evacuate the pipeline to be tested 31 to ensure that the airtightness of the pipeline to be tested 31 is good, and ensure that the subsequent measurement data is accurate.

[0094] In a specific embodiment, one end of the pipe to be tested 31 is connected to a pipeline, which extends from the pipe to be tested 31 through the side wall of the detection piece 1, and is connected to the second high-pressure gas source 81 and the second vacuum pump 74 through a three-way pipe joint. A valve is provided between the three-way pipe joint and the second high-pressure gas source 81 to control the connection relationship between the second high-pressure gas source 81 and the pipe to be tested 31, and a fourth valve 73 is provided between the three-way pipe joint and the second vacuum pump 74 to control the connection relationship between the pipe to be tested 31 and the second vacuum pump 74.

[0095] As a preferred embodiment, the non-metallic hydrogen pipeline gas leakage rate testing device further includes an exhaust gas treatment system 75, which is disposed between the first vacuum pump 72 and the second vacuum pump 74 and is connected to the first vacuum pump 72 and the second vacuum pump 74. The exhaust gas treatment system 75 is provided to recycle and reuse the gas extracted from the detection element 1 and the pipeline 31 to be tested.

[0096] In the present invention, after the pipeline to be tested is placed in the detection member 1, the detection member 1 is sealed, and the fourth valve 73 is first opened, and the second vacuum pump 74 of the second air extraction system vacuums and decompresses the pipeline to be tested 31; the third valve 71 is opened, and the first vacuum pump 72 of the first air extraction system vacuums and decompresses the detection member 1. Then, the valve between the second high-pressure gas source 81 and the pipeline to be tested 31 is opened, and the second high-pressure gas source 81 starts to inflate the pipeline to be tested 31. When the pressure of the pipeline to be tested 31 reaches the second preset pressure, the valve is closed. The pipeline to be tested 31 is tested for gas leakage rate. It should be understood that the vacuuming process of the pipeline to be tested 31 by the second vacuum pump 74 can be completed before the detection member 1 is placed in the detection member 1, or it can be completed after the detection member 1 is placed in the detection member 1, as long as it is performed before the second high-pressure gas source 81 inflates the pipeline to be tested 31.

[0097] As a preferred embodiment, the gas leakage rate test device for non-metallic hydrogen transmission pipelines further includes a support seat 32, which is slidably connected to the detection member 1, and the pipeline 31 to be tested is placed on the support seat 32. It should be understood that the sliding connection between the support seat 32 and the detection member 1 can be achieved in the following ways: a roller is provided at the bottom of the support seat 32; or a slide rail is provided in the detection member 1, and a pulley is provided at the bottom of the support seat 32, so that the support seat 32 loaded with the pipeline 31 to be tested can stably and conveniently enter the detection member 1.

[0098] There are also seals 33 at both ends of the pipeline to be tested 31, which are used to seal the pipeline to be tested 31 to prevent leakage of gas in the pipeline to be tested 31 due to loose sealing. When the pipeline to be tested 31 is located in the detection member 1, the detection member 1 contains the pipeline to be tested 31, the support seat 32, other components connected to the support seat 32, and a pipeline connected to the pipeline to be tested 31, and the test cavity 11 is a cavity not occupied by the components contained in the detection member 1.

[0099] As a preferred embodiment, at least one side of the detection member 1 has an opening for the pipe 31 to be tested to enter the detection member 1, and the opening has a detachable end seal. The detection member 1 is provided with at least one opening for loading the pipe 31 to be tested into the detection member 1. After the pipe 31 to be tested enters the detection member 1, the opening of the detection member 1 is sealed with the end seal to ensure that the gas in the detection member 1 will not leak, resulting in inaccurate test parameters.

[0100] As a preferred embodiment, the non-metallic hydrogen pipeline gas leakage rate test device further includes a pad 34, which is disposed at the bottom of the detection member 1 and is used to support the detection member 1. The pad 34 is used to support the entire test device to ensure the movement and stability of the entire test device.

[0101] The present invention also provides a method for testing the gas leakage rate of a non-metallic hydrogen pipeline, using the gas leakage rate testing device for the non-metallic hydrogen pipeline described in any of the above embodiments, the method comprising:

[0102] Step S1: After a sealed test cavity is formed by placing the pipe to be tested in the detection cavity, the test cavity is evacuated. Seal the two ends of the pipe to be tested with seals, pass the pipe to be tested into the detection part from the opening of the detection part, and seal the opening of the detection part with the end seal. Specifically, after the pipe to be tested is placed in the detection part, the detection part is sealed, and each pipeline is connected, and the air tightness of the entire device is checked, and the test cavity in the detection part is evacuated to ensure that the air tightness of the entire test device is good, so that the subsequent data measurement in the test cavity is accurate.

[0103] Step S2: exhaust the air in the pipeline to be tested, and inject gas of a second set pressure into the pipeline to be tested. That is, before the pipeline to be tested is inflated, the gas in the pipeline to be tested is first exhausted, and then the pipeline to be tested is inflated through the second high-pressure gas source. In another embodiment, the pipeline to be tested may not be exhausted before being inflated.

[0104] It should be understood that step S2 may be performed before step S1, that is, first seal the two ends of the pipeline to be tested with seals, first discharge the gas in the pipeline to be tested, then inflate the pipeline to be tested through a second high-pressure gas source, and inflate to a second preset pressure, then place the pipeline to be tested in the detection member, and seal the opening of the detection member with an end seal, so that a test cavity is formed in the detection member. Alternatively, step S2 may be performed after step S1, that is, first seal the two ends of the pipeline to be tested with seals, then place it in the detection member, and then seal the opening of the detection member with an end seal, so that a test cavity is formed in the detection member. Then discharge the gas in the pipeline to be tested, then inflate the pipeline to be tested through a second high-pressure gas source, and inflate to a second preset pressure. Preferably, step S2 is performed after step S1.

[0105] Specifically, after both ends of the pipe to be tested 31 are sealed, the second vacuum pump 74 can evacuate the pipe to be tested 31 to perform an airtightness test, and after determining that the airtightness of the pipe to be tested 31 is good, the pipe to be tested 31 is placed in the detection piece, and the detection piece is sealed, and then the pipe to be tested 31 is inflated through the second high-pressure gas source 81; or, after the pipe to be tested 31 is evacuated and it is determined that the airtightness is good, the pipe to be tested 31 is inflated through the second high-pressure gas source 81, and then the pipe to be tested 31 is placed in the detection piece 1, and the detection piece 1 is sealed; or, after both ends of the pipe to be tested 31 are sealed, the pipe to be tested 31 is placed in the detection piece 1, and the detection piece 1 is sealed, and then the pipe to be tested 31 is evacuated again, and after determining that the airtightness of the pipe to be tested 31 is good, the pipe to be tested 31 is inflated through the second high-pressure gas source 81.

[0106] Step S3: When the gas leakage in the pipeline to be tested reaches equilibrium, obtain the pressure change value of the test chamber within the preset time interval, and calculate the gas leakage rate of the pipeline to be tested based on the preset time interval, the pressure change value, the volume of the test chamber, and the current temperature in the test chamber. When the pressure change rate in the pipeline to be tested also tends to be stable, the gas leakage in the pipeline to be tested reaches equilibrium. At this time, a time interval is preset, and the pressure change value within the preset time interval is recorded, that is, the initial pressure of the test chamber at the initial time and the terminal pressure of the test chamber at the terminal time are recorded within the preset time interval, and then the pressure difference within the time period is calculated. Preferably, after the pipeline to be tested is placed in the detection component and inflated to the second set pressure through the second inflation pipeline, the gas in the pipeline to be tested begins to leak. After the gas leakage in the pipeline to be tested reaches equilibrium, a time interval is set to record the initial pressure of the test chamber at the initial time; The time after is the termination time, and the termination pressure of the test chamber at the termination time is recorded to obtain the pressure difference of the test chamber between the initial time and the termination time.

[0107] Then calculate the gas leakage rate of the pipeline to be tested by the first formula:

[0108]

[0109] Wherein, J represents the gas leakage rate of the pipeline to be tested, in mol / m / s; for The pressure change value of the test chamber within the time interval, the unit is P a ; is the preset time interval; V2 is the volume of the test chamber, in m 3 ; R is the molar gas constant, with a value of 8.314472, in J / mol / K; T is the current temperature in the test chamber, in K; L is the length of the pipeline to be tested, in m.

[0110] Among them, the use of the calibration chamber to determine the volume of the test chamber can be before step S3 or after step S3. Specifically, if the calibration chamber is used to determine the volume of the test chamber before step S3, that is, the use of the calibration chamber to determine the volume of the test chamber can be after the pipeline to be tested is placed in the shell and before the second high-pressure gas source inflates the pipeline to be tested. Alternatively, the calibration chamber is used to determine the volume of the test chamber after the second high-pressure gas source inflates the pipeline to be tested, and any time period before the pressure change rate area of ​​the test chamber stabilizes. Alternatively, the calibration chamber is used to determine the volume of the test chamber after step S3, that is, the calibration chamber is used to determine the volume of the test chamber after the gas leakage rate in the pipeline to be tested reaches a balanced state, the pressure change rate of the test chamber also tends to be stable, and the pipeline to be tested is still sealed in the detection component and has not been taken out. That is to say, in the non-metallic hydrogen pipeline gas leakage rate test method described in the present invention, the volume of the test chamber can be measured using the steps described in the present invention before and after the non-metallic hydrogen pipeline gas leakage test. It should be understood that if the volume of the test chamber is measured before the gas leakage test of the non-metallic hydrogen pipeline, the volume of the test chamber does not take into account the effect of the expansion of the pipeline to be tested on the volume of the test chamber, and there is an error in the measurement result of the volume of the test chamber; if the volume of the test chamber is measured after the gas leakage test of the non-metallic hydrogen pipeline, the volume of the test chamber takes into account the effect of the expansion of the pipeline to be tested on the volume of the test chamber, making the volume quantity of the test chamber more accurate, and thus making the determination of the gas leakage rate of the pipeline to be tested more precise.

[0111] The present invention also provides a method for testing the volume expansion of a non-metallic pipeline, which is applied to the gas leakage rate testing device of the non-metallic hydrogen pipeline described in any of the above embodiments. The method comprises: before performing the gas leakage rate test, a measuring unit calculates the first volume of the test chamber based on a second formula:

[0112]

[0113] Wherein, V1 represents the volume of the calibration chamber, V2 represents the volume of the test chamber, P1 represents the first pressure, P2 represents the second pressure, P3 represents the third pressure, T1 represents the first temperature, T2 represents the second temperature, and T3 represents the third temperature; the above-mentioned non-metallic pipeline gas leakage rate test is performed; after the above-mentioned test is completed, the measuring unit calculates the second volume of the test chamber based on the second formula, and calculates the volume expansion of the non-metallic pipeline based on the difference between the first volume and the second volume. Before the leakage rate test of the pipeline to be tested, the volume of the test chamber is measured, and the first volume of the test chamber is calculated according to the second formula; after the leakage rate test of the pipeline to be tested, the volume of the test chamber is measured, and the second volume of the test chamber is calculated according to the second formula, and the difference between the first volume and the second volume is calculated to obtain the volume expansion of the pipeline to be tested.

[0114] In one embodiment of the present invention, the pipeline 31 to be tested is placed in the opening of the detection member 1, and then the detection member 1 is sealed, and the test chamber 11 is formed inside the detection member 1. The second valve 223 between the calibration chamber 21 and the first high-pressure gas source 222 is opened, the first high-pressure gas source 222 and the calibration chamber 21 are connected, the calibration chamber 21 is inflated, and the gas is inflated to the first set pressure, the second valve is closed, the first pressure P1 and the first temperature T1 in the calibration chamber 21 are read, and the second pressure P2 and the second temperature T2 of the test chamber 11 are read. Next, the first valve 6 between the test chamber 11 and the calibration chamber 21 is opened, the calibration chamber 21 and the test chamber 11 are connected, the gas in the calibration chamber 21 and the test chamber 11 are mixed, and after the pressure and temperature in the test chamber 11 are stabilized, the third pressure P3 and the third temperature T3 of the test chamber 11 are recorded at this time, and then the first volume of the test chamber 11 is obtained according to the second formula.

[0115] Next, close the first valve 6 between the calibration chamber 21 and the test chamber 11, use the first vacuum pump 72 to evacuate the test chamber 11, and use the second vacuum pump 74 to evacuate the pipeline 31 to be tested. Then connect the second gas filling assembly and the pipeline 31 to be tested, and the second high-pressure gas source 81 inflates the pipeline 31 to be tested to the second set pressure, and start the leakage test of the pipeline 31 to be tested. After the hydrogen leakage of the pipeline 31 to be tested reaches a balanced state, record the pressure change value in the test chamber within the preset time interval and the current temperature in the test chamber, and then obtain the leakage rate of the pipeline 31 to be tested.

[0116] After the leakage rate test of the pipeline 31 to be tested is completed, the measuring unit measures the second volume in the test chamber 11 according to the above volume measurement method, and calculates the difference between the first volume and the second volume to obtain the volume expansion of the pipeline 31 to be tested.

[0117] In another embodiment of the present invention, the pipe to be tested 31 is placed in the opening of the detection member 1, and then the detection member 1 is sealed, and a test chamber 11 is formed between the inner wall of the detection member 1 and the pipe to be tested 31. The test chamber 11 is evacuated by a first vacuum pump 72, and the pipe to be tested 31 is evacuated by a second vacuum pump 74. Then, the second gas filling component and the pipe to be tested 31 are connected, and the pipe to be tested 31 is inflated to a second set pressure, and a leakage test of the pipe to be tested 31 is started. After the gas leakage of the pipe to be tested 31 reaches a balanced state, the pressure change value in the test chamber within a preset time interval and the current temperature in the test chamber are recorded.

[0118] Next, open the second valve 223 between the calibration chamber 21 and the first high-pressure gas source 222, connect the first high-pressure gas source 222 and the calibration chamber 21, inflate the calibration chamber 21 to the first set pressure, close the second valve 223, read the first pressure P1 and the first temperature T1 in the calibration chamber 21, and read the second pressure P2 and the second temperature T2 of the test chamber 11. Next, open the first valve 6 between the test chamber 11 and the calibration chamber 21 to connect the calibration chamber 21 and the test chamber 11, mix the gases in the calibration chamber 21 and the test chamber 11, and after the pressure and temperature in the test chamber 11 are stable, record the third pressure P3 and the third temperature T3 of the test chamber 11 at this time, close the first valve 6 between the calibration chamber 21 and the test chamber 11, and then calculate the volume of the test chamber 11 according to the second formula of the volume calculation formula of the test chamber 11, and calculate the gas leakage rate of the pipeline 31 to be tested according to the volume of the test chamber 11 and the pressure change value and temperature within a preset time interval after the gas leakage of the pipeline 31 to be tested is balanced.

[0119] In the gas leakage rate test method of the non-metallic hydrogen pipeline of the present invention, the first volume of the test chamber 11 can be obtained by measuring the volume of the test chamber 11 before the gas leakage test of the pipeline 31 to be tested, and the second volume of the test chamber 11 can be obtained by measuring the volume of the test chamber 11 after the gas leakage test of the pipeline 31 to be tested. The volume expansion change of the pipeline 31 to be tested is obtained by the difference between the first volume and the second volume, that is, the difference between the volume of the test chamber 11 before and after the gas leakage test of the pipeline 31 to be tested, and then the volume expansion amount of the pipeline 31 to be tested caused by the internal pressurization of the pipeline 31 to be tested is obtained. The difficulty of the displacement sensor being difficult to install and test due to the small volume of the test chamber 11 and the vacuum environment is solved. At the same time, the volume of the test chamber 11 can be measured after the gas leakage rate test is completed, without taking the pipeline out of the detection member 1 for re-measurement, and the volume of the test chamber 11 in this embodiment takes into account the expansion deformation of the pipeline 31 to be tested, and the test result is more accurate.

[0120] The present invention takes the gas leakage rate test of a non-metallic hydrogen transmission pipeline as an example to illustrate its specific implementation method in an actual application scenario.

[0121] Embodiment 1:

[0122] Taking the polyethylene pipe with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as an example, a helium leakage test is performed; wherein the volume of the calibration chamber 21 is the sum of the volumes of the calibration chamber and the pipeline connected thereto, and its volume is 0.02 m 3 , that is 20L.

[0123] Before the test, the second valve is opened to pressurize the calibration chamber 21, so that the pressure of the calibration chamber 21 reaches 0.21 MPa, and the temperature data of the calibration chamber 21 is read by the first temperature sensor 212 arranged on the calibration chamber 21, which is 30°C, i.e. 303.15 K. Then the second valve is closed, and the pressure reading of the second pressure sensor 12 of the test chamber 11 is 0.1 MPa, and the reading of the second temperature sensor 13 is 22°C, i.e. 295.15 K.

[0124] Open the first valve 6 connecting the calibration chamber 21 and the test chamber 11 to mix the gases in the calibration chamber 21 and the test chamber 11. After a period of time, it is observed that the reading of the second pressure sensor 12 of the test chamber 11 is stable at 0.11 MPa, and the reading of the second temperature sensor 13 is stable at 23°C, i.e. 296.15K.

[0125] According to the above data, the volume of the test chamber 11 before the test can be calculated by the second formula to be 0.197m 3 , that is 197L.

[0126]

[0127] Close the first valve 6 connecting the calibration chamber 21 and the test chamber 11, use the first vacuum pump 72 to evacuate the test chamber 11 to 10Pa, fill the tested pipe 31 with 1MPa high-pressure pure helium, and start the leakage test.

[0128] After the test, the steps of pressurizing and reading the calibration chamber 21 before the test, i.e. connecting the calibration chamber 21 and the test chamber 11 to mix the gases therein, are repeated. Before the gases in the calibration chamber 21 and the test chamber 11 are mixed, the pressure reading of the first pressure sensor 211 provided on the calibration chamber 21 is 0.195MPa, the temperature data of 30°C is read by the first temperature sensor 212, the pressure reading of the second pressure sensor 12 of the test chamber 11 is 2200Pa, and the reading of the second temperature sensor 13 is 23°C. After the gases in the calibration chamber 21 and the test chamber 11 are mixed, the reading of the second pressure sensor 12 of the test chamber 11 is 19865Pa, and the reading of the second temperature sensor 13 is 24°C.

[0129] Based on the above data, the volume of the test chamber 11 after the test is calculated to be 0.194 m 3 , that is 194L.

[0130] Therefore, the hydrogen pressure generated by hydrogen leakage can be corrected based on the above data, and the expansion amount of the tested pipeline 31 can be calculated to be 0.003 m 3 , that is 3L.

[0131] Embodiment 2:

[0132] Taking the polyethylene pipe with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as an example, a hydrogen leakage test is performed; wherein the volume of the calibration chamber 21 is the sum of the volumes of the calibration chamber and the pipeline connected thereto, and its volume is 0.02 m 3 , that is 20L.

[0133] Before the test, the second valve is opened to pressurize the calibration chamber 21, so that the pressure of the calibration chamber 21 reaches 0.21 MPa, and the temperature data of the calibration chamber 21 is read by the first temperature sensor 212 arranged on the calibration chamber 21, which is 30°C, i.e. 303.15 K. Then the second valve is closed, and the pressure reading of the second pressure sensor 12 of the test chamber 11 is 0.1 MPa, and the reading of the second temperature sensor 13 is 22°C, i.e. 295.15 K.

[0134] Open the first valve 6 connecting the calibration chamber 21 and the test chamber 11 to mix the gases in the calibration chamber 21 and the test chamber 11. After a period of time, it is observed that the reading of the second pressure sensor 12 of the test chamber 11 is stable at 0.11 MPa, and the reading of the second temperature sensor 13 is stable at 23°C, i.e. 296.15K.

[0135] According to the above data, the volume of the test chamber 11 before the test can be calculated by the second formula to be 0.197m 3 , that is 197L.

[0136]

[0137] Close the first valve 6 connecting the calibration chamber 21 and the test chamber 11, use the first vacuum pump 72 to evacuate the test chamber 11 to 10Pa, fill the tested pipe 31 with 1MPa high-pressure pure hydrogen, and start the leakage test.

[0138] After the test, the steps of pressurizing and reading the calibration chamber 21 before the test, i.e. connecting the calibration chamber 21 and the test chamber 11 to mix the gases therein, are repeated. Before the gases in the calibration chamber 21 and the test chamber 11 are mixed, the pressure reading of the first pressure sensor 211 provided on the calibration chamber 21 is 0.195MPa, the temperature data of 30°C is read by the first temperature sensor 212, the pressure reading of the second pressure sensor 12 of the test chamber 11 is 2000Pa, and the reading of the second temperature sensor 13 is 23°C. After the gases in the calibration chamber 21 and the test chamber 11 are mixed, the reading of the second pressure sensor 12 of the test chamber 11 is 19680Pa, and the reading of the second temperature sensor 13 is 24°C.

[0139] Based on the above data, the volume of the test chamber 11 after the test is calculated to be 0.194 m 3 , that is 194L.

[0140] Therefore, the hydrogen pressure generated by hydrogen leakage can be corrected based on the above data, and the expansion amount of the tested pipeline 31 can be calculated to be 0.003 m 3 , that is 3L.

[0141] Embodiment 3:

[0142] Taking the polyethylene pipe with an outer diameter of 110mm, a wall thickness of 10mm and a length of 1000mm as an example, a hydrogen leakage test is carried out. If the calibration chamber 21 is not used to calibrate the volume of the test chamber 11, the volume of the test chamber 11 calculated based on the geometric dimensions of the detection component 1, the test pipe 31, the end seal of the test pipe, etc. is 183L. After the hydrogen leakage of the non-metallic pipeline reaches equilibrium, the pressure reading of the second pressure sensor 12 of the test chamber 11 increases from 1200Pa to 2000Pa within a time interval of 1 hour, and the second temperature sensor 13 reads 23°C. At this time, the calculated hydrogen leakage rate of the non-metallic pipeline is 1.65 10 -5 mol / m / s.

[0143] The volume of the calibration chamber 21 of the present invention is the sum of the volumes of the calibration chamber 21 and the pipeline connected thereto, and its volume is 0.02m 3 , i.e. 20L. After the non-metallic pipeline hydrogen leakage rate test is completed, the calibration chamber 31 is used to calibrate the volume of the test chamber 11. The pressure reading of the first pressure sensor 211 installed in the calibration chamber 21 is 0.195MPa, the temperature data of the first temperature sensor 212 is 30°C, the pressure reading of the second pressure sensor 12 of the test chamber 1 is 2000Pa, and the reading of the second temperature sensor 13 is 23°C. After the calibration chamber 21 is connected with the test chamber 11, the reading of the second pressure sensor 12 of the test chamber 11 is 19680Pa, and the reading of the second temperature sensor 13 is 24°C. It is calculated that the volume of the test chamber 11 after the test is 0.194m 3 , which is 194L. The calculated hydrogen leakage rate of the non-metallic pipeline is 1.75 10 -5 mol / m / s.

[0144] It can be seen that if the volume measurement device and method described in the present invention are not used, the results of the non-metallic pipeline hydrogen leakage test will produce an error of 5.7%.

[0145] Embodiment 4:

[0146] Taking the polyethylene pipe with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as an example, a hydrogen leakage test is performed. The calibration chamber 21 is used to calibrate the volume of the test chamber 11. The volume of the calibration chamber 21 is the sum of the volumes of the calibration chamber 21 and the pipeline connected thereto, and its volume is 0.02m3 , i.e. 20 L. According to the calculation in Example 1, the volume of the test chamber before the hydrogen leakage test of the pipeline 31 to be tested is 197 L. If the volume of the test chamber 11 before the hydrogen leakage test of the pipeline 31 to be tested is used to calculate the pipeline hydrogen leakage rate (i.e., the expansion deformation during the non-metallic pipeline test is not considered), the non-metallic pipeline hydrogen leakage rate calculated at this time is 1.78 10 -5 mol / m / s.

[0147] By using the volume measurement device and method of the present invention, the volume of the test chamber is measured again after the hydrogen leakage test of the pipeline to be tested (i.e., the expansion deformation during the non-metallic pipeline test is taken into account). The volume of the test chamber after the hydrogen leakage test is 194L, and the calculated hydrogen leakage rate of the non-metallic pipeline is 1.75. 10 -5 mol / m / s.

[0148] It can be seen that if the expansion deformation during the non-metallic pipeline testing process is not taken into account, the results of the non-metallic pipeline hydrogen leakage test will produce an additional 1.7% error.

[0149] Embodiment 5:

[0150] Taking a polyethylene pipe with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as an example, a hydrogen leakage test was performed; the first temperature control component 23 and the second temperature control component 14 were installed in the calibration chamber 21 and the test chamber 11 respectively, so that the entire test process is a constant temperature environment. The volume of the calibration chamber 21 is the sum of the volumes of the calibration chamber 21 and the pipeline connected thereto, and its volume is 0.02m 3 , that is 20L.

[0151] Open the second valve 223 to pressurize the calibration chamber 21, so that the pressure of the calibration chamber 21 reaches 0.21MPa. Then close the second valve 223, and read the pressure reading of the second pressure sensor 12 of the test chamber 11, which is 0.1MPa; open the first valve 6 connecting the calibration chamber 21 and the test chamber 11, so that the gas in the calibration chamber 21 and the test chamber 11 are mixed. After a period of time, it is observed that the pressure sensor reading of the test chamber 11 is stable, which is 0.11MPa.

[0152] Using the above data, according to the third formula

[0153]

[0154] It can be calculated that the volume of the test chamber 11 is 0.02 m 3 , that is 200L.

[0155] Embodiment 6:

[0156] Taking the polyethylene pipe with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as an example, the volume of the test chamber 11 can be repeatedly measured. The volume of the calibration chamber 21 is the sum of the volumes of the calibration chamber 21 and the pipeline connected thereto, and the volume is 0.02 m 3 , that is 20L.

[0157] Taking the constant temperature test environment as an example, the second valve 223 is opened to pressurize the calibration chamber 21, so that the pressure of the calibration chamber 21 reaches 0.32MPa; then the second valve 223 is closed, and the pressure reading of the second pressure sensor 12 of the test chamber 11 is read as 0.1MPa; the first valve 6 connecting the calibration chamber 21 and the test chamber 11 is opened to mix the gas in the calibration chamber 21 and the test chamber 11. After a period of time, it is observed that the reading of the second pressure sensor 12 of the test chamber 11 is stable, which is 0.12MPa. It can be calculated that the volume of the test chamber 11 is 0.02m 3 , that is 200L.

[0158] Repeat the above steps, set the pressure of calibration chamber 21 to 0.64MPa, the pressure reading of test chamber 11 to 0.1MPa, and after the gas in calibration chamber 21 and test chamber 11 are mixed, the pressure reading of the second pressure sensor 12 of test chamber 11 is 0.15MPa. It can be calculated that the volume of test chamber 11 is 0.196m 3 , that is 196L.

[0159] The volume of the test chamber measured twice is averaged, so the volume of the test chamber can be obtained to be 0.198m 3 , which is 198 L. Of course, more accurate values ​​can be obtained through more repeated experiments.

[0160] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gas leakage rate testing device for non-metallic hydrogen pipelines, characterized in that: include: A detection member, wherein the detection member is formed with a detection cavity suitable for placing the pipeline to be tested, wherein a sealed test cavity is formed after the pipeline to be tested is placed in the detection cavity; a calibration chamber, the calibration chamber being selectively connected to the test chamber; A first gas filling assembly, the first gas filling assembly being selectively connected to the calibration chamber so as to be suitable for injecting gas of a first set pressure into the calibration chamber; a second gas filling assembly, the second gas filling assembly being selectively connected to the pipeline to be tested so as to be suitable for injecting gas of a second set pressure into the pipeline to be tested; a measuring unit configured to measure the pressure and temperature in the calibration chamber and the pressure and temperature in the test chamber, and calculate the volume of the test chamber based on a first pressure and a first temperature in the calibration chamber before the calibration chamber is connected to the test chamber, a second pressure and a second temperature in the test chamber, and a third pressure and a third temperature in the test chamber after the calibration chamber is connected to the test chamber and the leakage of the pipeline to be tested is balanced; A leakage rate testing unit, the leakage rate testing unit being configured to obtain a pressure change value of the test chamber within a preset time interval, and calculate the gas leakage rate of the pipeline to be tested based on the preset time interval, the pressure change value, the current temperature in the test chamber, and the volume of the test chamber after the leakage balance of the pipeline to be tested; The measuring unit calculates the volume of the test chamber based on a second formula: Among them, V1 represents the volume of the calibration chamber, V2 represents the volume of the test chamber, P1 represents the first pressure, P2 represents the second pressure, P3 represents the third pressure, T1 represents the first temperature, T2 represents the second temperature, and T3 represents the third temperature.

2. The gas leakage rate testing device according to claim 1, characterized in that: The leakage rate testing unit calculates the gas leakage rate of the pipeline to be tested based on the first formula: Wherein, J represents the gas leakage rate, is the pressure change value, is the preset time interval, V2 is the volume of the test chamber, R is the molar gas constant, T is the current temperature in the test chamber, and L is the length of the pipeline to be tested.

3. The gas leakage rate testing device according to claim 1, characterized in that: The measuring unit comprises: A first temperature sensor and a first pressure sensor are arranged corresponding to the calibration cavity; A second temperature sensor and a second pressure sensor are provided corresponding to the test chamber.

4. The gas leakage rate testing device according to any one of claims 1 to 3, characterized in that: The measuring unit further comprises: A first temperature control component, the first temperature control component corresponds to the calibration chamber setting; and a second temperature control component, the second temperature control component corresponds to the test chamber setting, the first temperature control component and the second temperature control component are used to adjust the second temperature to be consistent with the first temperature.

5. The gas leakage rate testing device according to claim 4, characterized in that: When the first temperature and the second temperature are consistent, the measuring unit calculates the volume of the test chamber based on a third formula: Among them, V1 represents the volume of the calibration chamber, V2 represents the volume of the test chamber, P1 represents the first pressure, P2 represents the second pressure, and P3 represents the third pressure.

6. The gas leakage rate testing device according to any one of claims 1 to 3, characterized in that: The sum of the internal volumes of the calibration chamber and the pipeline connected thereto is greater than or equal to 1 / 10 of the sum of the internal volumes of the test chamber and the pipeline connected thereto, and the sum of the internal volumes of the calibration chamber and the pipeline connected thereto is less than or equal to twice the sum of the internal volumes of the test chamber and the pipeline connected thereto.

7. The gas leakage rate testing device according to any one of claims 1 to 3, characterized in that: The pipeline to be tested includes a non-metallic pipeline and a connecting joint connected to the non-metallic pipeline, and the connecting joint is any one of a hot-melt joint, an electric-melt joint, and a mechanical joint.

8. The gas leakage rate testing device according to claim 1, characterized in that: The gas includes at least one of hydrogen, helium, natural gas, nitrogen, methane, gas and carbon dioxide.

9. A method for testing the gas leakage rate of a non-metallic hydrogen pipeline, characterized in that: Using the gas leakage rate testing device according to any one of claims 1 to 8, the method comprises: After the pipeline to be tested is placed in the detection cavity to form a sealed test cavity, the test cavity is evacuated; Exhausting the air in the pipeline to be tested, and injecting gas of a second set pressure into the pipeline to be tested; When the gas leakage in the pipeline to be tested reaches equilibrium, the pressure change value of the test chamber within a preset time interval is obtained, and the gas leakage rate of the pipeline to be tested is calculated based on the preset time interval, the pressure change value, the volume of the test chamber, and the current temperature in the test chamber.

10. A method for testing the volume expansion of a non-metallic hydrogen pipeline, characterized in that: Using the gas leakage rate testing device according to any one of claims 1 to 8, the method comprises: Before performing the gas leakage rate test, the measuring unit calculates the first volume of the test chamber based on the second formula: Wherein, V1 represents the calibration chamber volume, V2 represents the test chamber volume, P1 represents the first pressure, P2 represents the second pressure, P3 represents the third pressure, T1 represents the first temperature, T2 represents the second temperature, and T3 represents the third temperature; Performing the gas leakage rate test of the non-metallic hydrogen pipeline as claimed in claim 9; After the above test is completed, the measuring unit calculates the second volume of the test chamber based on the second formula, and calculates the volume expansion of the pipeline to be tested based on the difference between the first volume and the second volume.

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