Gas leakage rate testing apparatus and method for nonmetal hydrogen conveying pipeline

Abstract

A gas leakage rate testing apparatus and method for a nonmetal hydrogen conveying pipeline, and a nonmetal hydrogen conveying pipeline volume expansion amount testing method. The gas leakage rate testing apparatus comprises: a test member (1), in which a test cavity (16) adapted to place a pipeline (31) to be tested is formed, wherein a sealed test cavity (11) is formed after said pipeline (31) is placed in the test cavity (16); a calibration cavity (21) selectively communicated with the test cavity (11); a first gas filling assembly (10) selectively communicated with the calibration cavity (21) so as to be adapted to inject gas of a first set pressure into the calibration chamber (21); a measurement unit (9) configured to measure the pressure and temperature in the calibration cavity (21) and the pressure and temperature in the test cavity (11), and calculate the volume of the test cavity (11); and a leakage rate test unit configured to acquire a pressure change value of the test cavity (11) within a preset time interval, and calculate the gas leakage rate of said pipeline (31). The technical problem that gas leakage rate testing is inaccurate due to the measurement of the volume of the test cavity (11) being difficult or inaccurate is solved. In the nonmetal hydrogen conveying pipeline volume expansion amount testing method, after gas leakage rate testing is ended, a measurement unit (9) calculates a second volume of a test cavity (11) on the basis of a second formula, and on the basis of the difference between a first volume and the second volume, calculates the volume expansion amount of a pipeline (31) to be tested.

Description

Gas permeation rate testing device and method for non-metal hydrogen transmission pipeline

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure is based on and claims priority to Chinese Patent Application No. 202411110660.5, filed on August 14, 2024, and Chinese Patent Application No. 202410538292.8, filed on April 30, 2024, the contents of which are hereby incorporated by reference in their entirety into the present disclosure. TECHNICAL FIELD

[0003] The present disclosure relates to the field of gas transmission and leakage testing, and in particular to a gas permeation rate testing device and method for non-metal hydrogen transmission pipeline. BACKGROUND

[0004] Due to the special physicochemical properties of hydrogen, the traditional pipeline must be a seamless steel pipe with low carbon and high strength, which has high material cost and great construction difficulty, resulting in a construction cost of about 4.5-6 million yuan per kilometer. In addition, the hydrogen embrittlement failure of the pipeline material needs to be considered in long-term use. The higher the hydrogen pressure and the higher the material strength, the more obvious the hydrogen embrittlement and hydrogen-induced cracking phenomenon, which inevitably leads to pipeline damage in use. Therefore, using non-metal to build a hydrogen transmission pipeline is a way to solve the high material cost of hydrogen pipeline construction.

[0005] However, non-metal pipelines have the problem of hydrogen leakage. Hydrogen permeation can cause deterioration of the mechanical properties of non-metal pipelines, and also cause hydrogen leakage, affecting safety and transmission efficiency, which is the biggest factor limiting the application of non-metal materials in the hydrogen transmission field. In practical applications, non-metal hydrogen transmission pipelines can be used for the transmission of pure hydrogen or hydrogen-doped gas, such as hydrogen-doped natural gas. Therefore, it is necessary to develop a gas permeation rate testing device for non-metal hydrogen transmission pipelines to test the permeation rate of hydrogen and other gases.

[0006] The applicant's prior patent ZL202210747875.2, entitled "A non-metal pipe hydrogen permeation rate testing device and method" discloses a non-metal pipe hydrogen permeation rate testing device and method, which has good testing efficiency and accurate calculation results for non-metal pipes. However, in actual application, it is found that the device and method at least have the following deficiencies: first, it can usually only test pipes of specific shape and outer diameter, and the pipe outer diameter and the test cylinder inner diameter need to be accurately matched, and it cannot be used for testing pipes of various specifications. Second, in the non-metal pipe gas leakage rate test, the size of the test cavity has a great influence on the test accuracy, but it is difficult to accurately measure the volume of the test cavity. The difficulty of accurate measurement mainly lies in the following aspects:

[0007] 1) The test pipe needs to be sealed at both ends during the leakage test, and the sealing element is an irregular-shaped workpiece, which is difficult to accurately measure in volume, and the cooperation between the sealing element and the test pipe needs to be considered, making the volume measurement more difficult;

[0008] 2) The test pipe needs to be ringed with reinforcing elements and axially with reinforcing elements, and although their volumes are fixed, the connecting elements between them and the test pipe, which are often many bolts and nuts, are difficult to accurately measure in volume;

[0009] 3) When high-pressure hydrogen is filled into the test pipe, the pipe will inevitably deform, which may be local or overall, and the volume change caused by the deformation of the pipe is also difficult to measure;

[0010] 4) The test cavity needs to reserve many sensor interfaces, valve interfaces, etc., and the volume measurement of these is often difficult.

[0011] In the non-metal pipe gas leakage rate test, it is also necessary to explore the influence of the internal gas pressure change of the pipe on the pipe deformation, so it is necessary to measure the pipe deformation, but in the vacuum environment of the test cavity, the displacement sensor, strain gauge and other methods for measuring the pipe deformation are often limited in use, and the accuracy of the measured pipe deformation is poor. SUMMARY

[0012] The present disclosure provides a gas leakage rate testing device and method for non-metal hydrogen conveying pipes to solve the technical problem of inaccurate gas leakage rate test caused by difficult or inaccurate volume measurement.

[0013] To solve the above technical problems, the present disclosure provides a gas leakage rate testing device for a non-metal hydrogen pipeline, comprising: a detection piece, the detection piece is formed with a detection cavity suitable for placing a pipeline to be tested, wherein the detection cavity forms a sealed test cavity after the pipeline to be tested is placed in the detection cavity; a calibration cavity, the calibration cavity is in selective communication with the test cavity; a first gas injection assembly, the first gas injection assembly is in selective communication with the calibration cavity, so as to inject a gas at a first set pressure into the calibration cavity; a second gas injection assembly, the second gas injection assembly is in selective communication with the pipeline to be tested, so as to inject a gas at a second set pressure into the pipeline to be tested; a measurement unit configured to measure the pressure and temperature in the calibration cavity and the pressure and temperature in the test cavity, and calculate the calculated volume of the test cavity based on the first pressure and the first temperature in the calibration cavity before the calibration cavity is in communication with the test cavity, the second pressure and the second temperature in the test cavity, and the third pressure and the third temperature in the test cavity after the pipeline to be tested leaks to equilibrium; a leakage rate testing unit configured to obtain a pressure change value of the test cavity 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 cavity, and the calculated volume of the test cavity after the pipeline to be tested leaks to equilibrium.

[0014] The measurement unit calculates the calculated volume of the test cavity based on the following second formula:

[0015] Wherein V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, 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.

[0016] As a preferred embodiment, the leakage rate testing unit calculates the gas leakage rate of the pipeline to be tested based on the following first formula:

[0017] Wherein J represents the gas leakage rate of the non-metal hydrogen pipeline, ΔP is the pressure change value, Δt is the preset time interval, V2 is the calculated volume of the test cavity, R is the molar gas constant, T is the current temperature in the test cavity, and L is the length of the pipeline to be tested.

[0018] As a preferred embodiment, the measurement unit comprises: a first temperature sensor and a first pressure sensor corresponding to the calibration cavity; a second temperature sensor and a second pressure sensor corresponding to the test cavity.

[0019] As a preferred embodiment, the measuring unit further comprises a first temperature control component arranged corresponding to the calibration cavity, and a second temperature control component arranged corresponding to the test cavity, the first temperature control component and the second temperature control component being used to adjust the second temperature to be the same as the first temperature.

[0020] As a preferred embodiment, in the case that the first temperature is the same as the second temperature, the measuring unit calculates the calculated volume of the test cavity based on the following third formula:

[0021] wherein V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, P1 represents the first pressure, P2 represents the second pressure, and P3 represents the third pressure.

[0022] As a preferred embodiment, the sum of the internal volume of the calibration cavity and the pipeline connected thereto is greater than or equal to 1 / 10 of the sum of the internal volume of the test cavity and the pipeline connected thereto, and the sum of the internal volume of the calibration cavity and the pipeline connected thereto is less than or equal to 2 times the sum of the internal volume of the test cavity and the pipeline connected thereto.

[0023] As a preferred embodiment, the pipeline to be tested comprises a non-metal pipeline and a connecting joint connected to the non-metal pipeline, the connecting joint being any one of a hot melt joint, an electric melt joint, and a mechanical joint.

[0024] As a preferred embodiment, the gas comprises at least one of hydrogen, helium, natural gas, nitrogen, methane, gas, and carbon dioxide.

[0025] The present disclosure further provides a gas leakage rate testing method for a non-metal hydrogen pipeline, applied to the gas leakage rate testing device of any one of the above embodiments, the method comprising: after placing the pipeline to be tested in the detection cavity to form a sealed test cavity, performing vacuumization on the test cavity; discharging air in the pipeline to be tested, and injecting a gas at a second set pressure into the pipeline to be tested; in the case that gas leakage in the pipeline to be tested reaches equilibrium, obtaining a pressure change value of the test cavity within a preset time interval, and calculating a gas leakage rate of the pipeline to be tested based on the preset time interval, the pressure change value, and a calculated volume of the test cavity and a current temperature in the test cavity.

[0026] The present disclosure further provides a volume expansion amount testing method for a non-metal hydrogen pipeline, applied to the gas leakage rate testing device of any one of the above embodiments, the method comprising: before performing gas leakage rate testing, the measuring unit calculates a first volume of the test cavity based on the following second formula:

[0027] wherein, V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, 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 a gas leakage rate test of a non-metal pipeline; after the above test is completed, the measuring unit calculates a second volume of the test cavity based on the second formula, and calculates a volume expansion amount of the pipeline to be tested based on the difference between the first volume and the second volume.

[0028] Compared with the prior art, the embodiments of the present disclosure have the following beneficial effects:

[0029] 1. The present disclosure adds a calibration cavity, accurately calibrates the calculated volume of the test cavity by measuring the pressure and temperature changes in the test cavity, and the device can be applied to the calculation of the volume of a test cavity of any shape. Avoid the problem that the volume is difficult to measure due to the complex structure of the pipeline joint and connecting pipeline, so as to realize a set of equipment to measure and detect different structures, configurations, and shapes of the test cavity inside the pipeline to be tested after the test cavity inside the pipeline to be tested.

[0030] 2. The detection part of the present disclosure can accommodate different shapes and specifications of the pipeline to be tested and the connecting pipeline, and the calculated volume change of the test cavity is accurately determined, which improves the accuracy of the test data of the gas leakage rate of the non-metal hydrogen pipeline.

[0031] Additional aspects and advantages of the present disclosure will be partially given in the following description, partially will become apparent from the following description, or will be understood by those skilled in the art through the practice of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0032] Fig. 1 is a structural schematic view of a non-metal hydrogen pipeline gas leakage rate test device of the present disclosure;

[0033] Fig. 2 is a structural schematic view of a calibration cavity in a non-metal hydrogen pipeline gas leakage rate test device of the present disclosure;

[0034] Fig. 3 is a schematic view of the internal structure of a detection part of a non-metal hydrogen pipeline gas leakage rate test device of the present disclosure;

[0035] Fig. 4 is a schematic view of the calibration steps of one embodiment of the calibration method of the volume measuring device of the present disclosure.

[0036] The reference signs in the drawings of the specification are as follows: 1-detection piece; 11-test cavity; 12-second pressure sensor; 13-second temperature sensor; 14-second temperature control assembly; 16-detection cavity; 21-calibration cavity; 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-supporting seat; 33-sealing piece; 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-waste gas treatment system; 8-second gas filling assembly; 81-second high-pressure gas source; 82-fourth pipeline; 9-measuring unit; 10-first gas filling assembly. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present disclosure.

[0038] The gas leakage rate testing device for the non-metal hydrogen pipeline provided by the embodiments of the present disclosure comprises a volume measuring device and a leakage rate testing unit, wherein the volume measuring device comprises a detection piece 1, a calibration cavity 21, a first gas filling assembly 10, a second gas filling assembly 8, and a measuring unit 9.

[0039] Please refer to FIG. 1 to FIG. 3, the detection piece 1 is formed with a detection cavity 16 suitable for placing the pipeline 31 to be tested, wherein the detection cavity 16 forms a sealed test cavity 11 after placing the pipeline 31 to be tested in it, that is, the inside of the detection piece 1 is a cavity structure, and the detection cavity 16 not occupied in the inside of the detection piece 1 forms the test cavity 11. The test cavity 11 formed in the detection piece 1 can be of any shape, that is, the pipeline 31 to be tested can be of any shape, and then the test cavity 11 not occupied in the detection cavity 16 can be of any shape.

[0040] The calibration cavity 21 is in selective communication with the test cavity 11, i.e. the communication between the calibration cavity 21 and the test cavity 11 can be controlled to be in communication or not in communication by a control component such as a valve. The first gas filling assembly 10 is in selective communication with the calibration cavity 21, so as to be suitable for injecting a gas at a first set pressure into the calibration cavity 21, wherein the first set pressure can be calibrated according to the actual measurement working condition. That is to say, the calibration cavity 21 is internally a hollow cavity structure, the hollow cavity forms a containing cavity containing the gas, and when the calibration cavity 21 is in communication with the first gas filling assembly 10, the first gas filling assembly 10 inflates the calibration cavity 21. When the calibration cavity 21 is in communication with the test cavity 11, the gas in the calibration cavity 21 mixes with the gas in the test cavity 11.

[0041] The measurement unit 9 is configured to measure the pressure and temperature in the calibration cavity 21 and the pressure and temperature in the test cavity 11, so as to calculate the calculated volume of the test cavity 11 based on the first pressure and the first temperature in the calibration cavity 21, the second pressure and the second temperature in the test cavity 11 before the calibration cavity 21 is in communication with the test cavity 11, and the third pressure and the third temperature in the test cavity 11 after the calibration cavity 21 is in communication with the test cavity 11. It should be understood that the measurement of the third pressure and the third temperature in the test cavity 11 after the calibration cavity 21 is in communication with the test cavity 11 can be before the gas leakage rate test of the pipeline 31 to be tested, or after the gas leakage rate test.

[0042] As a preferred embodiment, the measurement unit 9 comprises: a first temperature sensor 212 and a first pressure sensor 211 arranged corresponding to the calibration cavity 21, the first temperature sensor 212 is used to measure the temperature in the calibration cavity 21, and the first pressure sensor 211 is used to measure the pressure in the calibration cavity 21; a second temperature sensor 13 and a second pressure sensor 12 arranged corresponding to the test cavity 11, the second temperature sensor 13 is used to measure the temperature in the test cavity 11, and the second pressure sensor 12 is used to measure the pressure in the test cavity 11. Wherein, 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 realize the temperature measurement of the calibration cavity 21 and the test cavity 11. The measurement of the pressure in the calibration cavity 21 and the pressure in the test cavity 11 by the measurement unit 9 can also be realized by instruments such as pressure gauges that can realize the pressure measurement of the calibration cavity 21 and the test cavity 11.

[0043] In the present disclosure, the inside of the detection piece 1 is configured as a cavity structure, and the inside space is a detection cavity 16, which forms a test cavity 11 after placing the pipeline to be tested 31 inside. The measurement unit 9 is used to measure the pressure and temperature in the test cavity 11 and the calibration cavity. The calibration cavity 21 is in selective communication with the first aeration assembly 10, and the calibration cavity 21 is in selective communication with the test cavity 11. The first aeration assembly 10 is in selective communication with the calibration cavity 21 through a pipeline, and is used to aerate the calibration cavity 21. When it is necessary to calibrate the calculated volume of the test cavity 11 with the calibration cavity 21, the first aeration assembly 10 is in communication with the calibration cavity 21, and the calibration cavity 21 is in a non-communication state with the test cavity 11 at this time, the first aeration assembly 10 aerates the calibration cavity 21 to a first set pressure, closes the communication relationship between the first aeration assembly 10 and the calibration cavity 21, records the first pressure and the first temperature in the calibration cavity 21, and records the second pressure and the second temperature in the test cavity; the calibration cavity 21 and the test cavity 11 are communicated, the gas in the calibration cavity 21 mixes with the gas in the test cavity 11, the third temperature and the third pressure of the test cavity 11 are recorded, and then the calculated volume of the test cavity 11 is calculated.

[0044] The present disclosure precisely obtains the calculated volume of the calibration cavity 21 by adding the calibration cavity 21, and accurately calibrates the calculated volume of the test cavity 11 by measuring the pressure and temperature changes in the test cavity 11, and the structure can be applied to the calculation of the calculated volume of the test cavity 11 of any shape, that is, the detection piece 1 of the volume measuring device can be applied to any shape of the pipeline to be tested 31 or the connecting joint placed inside. The difficulty of volume measurement caused by complex structure and structure cooperation is avoided, so that a set of equipment is used to measure the calculated volume of the test cavity 11 inside the detection piece 1 after placing the pipeline to be tested 31 or the connecting joint with different structure configurations and different shapes inside the detection piece 1.

[0045] Specifically, the test cavity 11 and the calibration cavity 21 are in communication through the first pipeline 4 and the second pipeline 5, and the first valve 6 is arranged at the connection of the first pipeline 4 and the second pipeline 5. The first pipeline 4 is in communication with the test cavity 11, and the second pipeline 5 is in communication with the calibration cavity 21. When it is necessary to calibrate the calculated volume of the test cavity 11 with the calibration cavity 21, the first aeration assembly 10 is in communication with the calibration cavity 21, and the calibration cavity 21 is in a non-communication state with the detection piece 1 at this time, the first aeration assembly 10 aerates the calibration cavity 21 to a first set pressure, closes the communication relationship between the first aeration assembly 10 and the calibration cavity 21, records the first pressure and the first temperature in the calibration cavity 21, and records the second pressure and the second temperature in the test cavity 11; the first valve 6 is opened to communicate the calibration cavity 21 and the test cavity 11, the gas in the calibration cavity 21 mixes with the gas in the test cavity 11 through the second pipeline 5 and the first pipeline 4, the third temperature and the third pressure of the test cavity 11 are recorded, and then the calculated volume of the test cavity 11 is calculated.

[0046] Further, the first gas filling assembly 10 comprises a third pipeline 221 and a first high-pressure gas source 222, the third pipeline 221 is arranged between the calibration cavity 21 and the first high-pressure gas source 222, and is used to connect the calibration cavity 21 and the first high-pressure gas source 222, and the third pipeline 221 is provided with a second valve 223. The part of the third pipeline between the calibration cavity 21 and the second valve 223 is always in communication with the calibration cavity 21, and the volume in this part of the pipeline should be calculated when calculating the calculation volume of the calibration cavity 21. The calibration cavity 21 is also always in communication with the second pipeline 5, and the volume in the second pipeline 5 should also be calculated when calculating the calculation volume of the calibration cavity 21. Therefore, the calculation volume of the calibration cavity 21 is equal to the sum of the volumes in the calibration cavity 21, the second pipeline 5 in communication with the calibration cavity 21, and the third pipeline 221 between the calibration cavity 21 and the second valve 223. When the calculation volume of the test cavity 11 needs to be calibrated by the calibration cavity 21, the second valve 223 is opened, the first high-pressure gas source 222 is connected to the calibration cavity 21 through the third pipeline 221, the calibration cavity 21 is not in communication with the test cavity 11 at this time, the first high-pressure gas source 222 fills the calibration cavity 21 to a first set pressure, the second valve 223 is closed, that is, the communication between the first high-pressure gas source 222 and the calibration cavity 21 is closed, the first pressure and the first temperature in the calibration cavity 21 are recorded, and the second pressure and the second temperature in the test cavity 11 are recorded. The first valve 6 is opened to connect the calibration cavity 21 and the test cavity 11, and the gas in the calibration cavity 21 is mixed into the test cavity 11 through the second pipeline 5 and the first pipeline 4, the third temperature and the third pressure of the test cavity 11 are recorded, and then the calculation volume of the test cavity 11 is calculated. The calculation volume of the test cavity 11 can be measured before or after the gas leakage rate test of the pipeline to be tested 31.

[0047] It should be understood that the detection member 1, the calibration cavity 21, all the connecting pipelines, and the control valves in the present disclosure are all made of hydrogen-blocking materials, such as austenitic stainless steel, low-alloy steel, precipitation-strengthened austenitic alloy, and aluminum alloy materials.

[0048] As a preferred embodiment, the volume measuring device further comprises a second gas filling assembly 8, the second gas filling assembly 8 is selectively connected to the pipeline to be tested 31, and is adapted to inject a second set pressure of gas into the pipeline to be tested 31, and the value of the second set pressure can be calibrated in advance. The measuring unit 9 is further configured to calculate the calculation volume of the test cavity 11 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 11, 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 after the pipeline to be tested 31 is injected with the second set pressure of gas.

[0049] Specifically, the second gas filling assembly 8 is in selective communication with the pipeline to be tested 31 for filling the pipeline to be tested 31 with gas. The detection member 1 has a hollow structure inside. The pipeline to be tested 31 can be placed in the space inside the detection member 1, so that the detection member 1 also has a hollow structure that is not occupied. The hollow structure forms a test cavity 11. When the gas leakage rate of the pipeline to be tested 31 needs to be tested, and / or the calculated volume of the test cavity 11 needs to be measured, the two ends of the pipeline 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. The pipeline to be tested 31 is filled with gas by the second gas filling assembly 8, and the pipeline to be tested 31 is filled with gas to a second set pressure. Then, based on the first pressure and the first temperature in the calibration cavity 21 before the calibration cavity 21 is in communication with the test cavity 11, the second pressure and the second temperature in the test cavity 11, and the third pressure and the third temperature in the test cavity 11 after the calibration cavity 21 is in communication with the test cavity 11, the calculated volume of the test cavity 11 is calculated. It should be understood that after the pipeline to be tested 31 is filled with gas by the second gas filling assembly 8, the gas leakage rate of the pipeline to be tested 31 is tested first. After the gas leakage rate test of the pipeline to be tested 31 is completed, the calculated volume of the test cavity 11 is calibrated by the measurement unit 9. Wherein, the completion of the gas leakage rate test of the pipeline to be tested 31 refers to that after the gas leakage of the pipeline to be tested 31 is balanced, the pressure change in the test cavity 11 within a preset time interval is measured, and the current temperature in the test cavity 11 and the calculated volume of the test cavity 11 after the gas leakage of the pipeline to be tested 31 is balanced are obtained. The gas leakage rate of the pipeline to be tested 31 is obtained. By measuring the first temperature and the first pressure in the calibration cavity 21 before the test cavity 11 is in communication with the calibration cavity 21, the second temperature and the second pressure in the test cavity 11, and the third pressure and the third temperature in the test cavity 11 after the test cavity 11 is in communication with the calibration cavity 21, the calculated volume of the test cavity 11 is calculated. Since the pipeline to be tested 31 has been subjected to the gas leakage rate test at this time, the pipeline to be tested 31 has been expanded due to the internal gas pressure. Therefore, the calculated volume of the test cavity 11 is the calculated volume after the expansion and deformation of the pipeline to be tested 31, which solves the problem of measurement error of the calculated volume of the sealed test cavity 11 caused by the expansion and deformation of the pipeline to be tested 31 during the test, thereby realizing more accurate data for the gas leakage rate test of the pipeline to be tested 31.

[0050] It should be understood that after the two ends of the pipeline to be tested 31 are sealed, the pipeline to be tested 31 can be filled with gas by the second gas filling assembly 8 first, and then the pipeline to be tested 31 is placed in the detection member 1, and the detection member 1 is sealed. Or, after the two ends of the pipeline to be tested 31 are sealed, the pipeline to be tested 31 is placed in the detection member 1, and the detection member 1 is sealed. Then, the pipeline to be tested 31 is filled with gas by the second gas filling assembly 8.

[0051] After the two ends of the pipeline 31 to be tested are sealed and placed in the detection piece 1, the detection piece 1 is sealed, and since the pipeline 31 to be tested occupies the volume of the detection piece 1 after being placed in the detection piece 1, the internal space of the detection piece 1 not occupied is the test cavity 11. After the gas leakage in the pipeline 31 to be tested is balanced, the calculated volume and pressure change of the test cavity 11 can be obtained to obtain the gas leakage rate of the pipeline 31 to be tested. The calculated volume of the test cavity 11 is calibrated by the volume measuring device, and the calculated volume of the test cavity 11 is measured according to the method described herein according to the ideal gas state equation. The measurement of the calculated volume of the test cavity 11 is not limited by the structure and shape, that is, any shape, any structure is placed in the detection piece 1 in any way to form any pattern of the test cavity 11, and the calculated volume of the test cavity 11 can be measured according to the volume measurement method described herein. During the gas leakage rate test of the pipeline 31 to be tested, the shape and structure of the pipeline and the shape and structure of other structures connected to the pipeline do not need to be considered, and the calculated volume of the test cavity 11 can be calibrated by the volume measurement method described herein, and then the gas leakage rate of the pipeline 31 to be tested is obtained.

[0052] As a preferred embodiment, the second gas filling assembly 8 comprises a second high-pressure gas source 81 and a fourth pipeline 82, and the second high-pressure gas source 81 is communicated with the pipeline 31 to be tested through the fourth pipeline 82. The fourth pipeline 82 is also provided with a valve. When the valve is opened, the second high-pressure gas source 81 fills the pipeline 31 to be tested with gas; when the valve is closed, the second high-pressure gas source 81 is not communicated with the pipeline 31 to be tested, and the second high-pressure gas source 81 stops filling the pipeline 31 to be tested with gas.

[0053] As a preferred embodiment, the pipeline 31 to be tested comprises a non-metal pipeline and a connecting joint connected to the non-metal pipeline, and the connecting joint is any one of a hot melt joint, an electric melt joint, and a mechanical joint. That is, the pipeline 31 to be tested can be a non-metal pipeline, or can be a whole of the non-metal pipeline and the connecting joint connected to the non-metal pipeline, and the connecting joint can be any one of a hot melt joint, an electric melt joint, and a mechanical joint. The gas leakage rate test method of the non-metal hydrogen conveying pipeline of the present disclosure can be used to measure the gas permeation and gas leakage of the non-metal pipeline and the connecting joint connected to the non-metal pipeline. It should be understood that if the pipeline 31 to be tested needs to be filled with gas after being placed in the detection piece 1, the pipeline communicated between the second high-pressure gas source 81 and the pipeline 31 to be tested should be communicated with the second high-pressure gas source 81 at one end and communicated with the pipeline 31 to be tested through the side wall of the detection piece 1 into the interior of the detection piece 1 at the other end.

[0054] 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-doped natural gas, etc. It should be understood that the non-metallic hydrogen pipeline can not only be used for the transportation of pure hydrogen, but also for the transportation of hydrogen-doped gas, such as hydrogen-doped natural gas. Therefore, in order to explore the leakage rate of hydrogen-doped mixed gas, it is necessary to test the leakage of non-metallic hydrogen pipeline for hydrogen, helium, natural gas, nitrogen, methane, gas, carbon dioxide and their mixed gases.

[0055] As a preferred embodiment, the volume measuring device further comprises a first temperature control assembly 23 corresponding to the calibration cavity 21, so as to adjust the first temperature to be the same as the second temperature. The first temperature control assembly 23 is arranged in the calibration cavity 21, so as to adjust the temperature of the gas in the calibration cavity 21. When the temperature in the calibration cavity 21 is different from that in the test cavity 11, the sensor transmits a signal to the controller, the controller issues a corresponding instruction according to the temperature difference between the calibration cavity 21 and the test cavity 11, and the actuator executes the instruction issued by the controller to adjust the temperature in the calibration cavity 21, so that the temperature in the calibration cavity 21 is the same as that in the test cavity 11, thereby facilitating the calculation of the calculated volume of the test cavity 11. The sensor can be a temperature sensor, the controller can be a single-chip microcomputer, and the actuator can control the flow of hot water or cold water through an electromagnetic valve to adjust the temperature.

[0056] As a preferred embodiment, the volume measuring device further comprises a second temperature control assembly 14 corresponding to the test cavity 11, so as to adjust the second temperature to be the same as the first temperature. The second temperature control assembly 14 is arranged on the detection piece 1 corresponding to the test cavity 11, so as to adjust the temperature of the gas in the test cavity 11. When the temperature in the calibration cavity 21 is different from that in the test cavity 11, the sensor transmits a signal to the controller, the controller issues a corresponding instruction according to the temperature difference between the calibration cavity 21 and the test cavity 11, and the actuator executes the instruction issued by the controller to adjust the temperature in the test cavity 11, so that the temperature in the test cavity 11 is the same as that in the calibration cavity 21, thereby facilitating the calculation of the calculated volume of the test cavity 11.

[0057] It should be understood that the first temperature control assembly 23 can be arranged only in the calibration cavity 21 to control the temperature in the calibration cavity 21 so that the temperature in the calibration cavity 21 is the same as the temperature in the test cavity 11, and the test cavity 11 is not provided with a temperature control assembly; or the second temperature control assembly 14 can be arranged in the test cavity 11 to control the temperature in the test cavity 11 so that the temperature in the test cavity 11 is the same as the temperature in the calibration cavity 21, and the calibration cavity 21 is not provided with a temperature control assembly; preferably, the first temperature control assembly 23 is arranged in the calibration cavity 21, and the second temperature control assembly 14 is arranged in the test cavity 11, and the temperatures in the test cavity 11 and the calibration cavity 21 are controlled to ensure that the temperatures in the test cavity 11 and the calibration cavity 21 are the same, i.e., the first temperature, the second temperature, and the third temperature are the same. That is, the first temperature control assembly 23 and / or the second temperature control assembly 14 are arranged to keep the temperatures in the test cavity 11 and the calibration cavity 21 the same when the calculation volume of the test cavity 11 is measured, thereby facilitating the measurement of the calculation volume of the test cavity 11. The specific arrangement of the first temperature control assembly 23 and the second temperature control assembly 14 in the calibration cavity 21 and the test cavity 11 can be determined according to specific conditions.

[0058] In one possible embodiment, the first temperature control assembly 23 can include a plurality of temperature sensors arranged in the calibration cavity 21 so that the temperature of each region in the calibration cavity 21 can be controlled to ensure that the temperature of each region in the calibration cavity 21 is the same. The second temperature control assembly 14 includes a plurality of temperature sensors arranged on the inner wall of the detection member 1 so that the temperature of each region in the test cavity 11 can be controlled to ensure that the temperature of each region in the test cavity 11 is the same.

[0059] Specifically, the measurement unit calculates the calculation volume of the test cavity based on the following second formula:

[0060] Wherein, V1 represents the calculation volume of the calibration cavity, V2 represents the calculation volume of the test cavity, 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, the influence of the internal volume of the pipeline is considered, and here the calculation volume V1 of the calibration cavity should be understood as the sum of the internal volume of the calibration cavity and the pipeline connected thereto, and similarly, the calculation volume V2 of the test cavity should be understood as the sum of the internal volume of the test cavity and the pipeline connected thereto.

[0061] Specifically, referring to FIG. 4, the volume measurement method of the volume measurement device includes the following steps:

[0062] Step S41: open the second valve, fill the calibration cavity with the first high-pressure gas source of the first gas filling assembly to the first set pressure, and record the first pressure P1 and the first temperature T1 in the calibration cavity, then close the second valve; at this time, the first valve between the test cavity and the calibration cavity is closed, the test cavity and the calibration cavity are not connected, and the second pressure P2 and the second temperature T2 of the test cavity when the calibration cavity and the test cavity are not connected are recorded.

[0063] Step S42: open the first valve between the calibration cavity and the test cavity, connect the calibration cavity and the test cavity, so that the gases in the calibration cavity and the test cavity are mixed, and after the gases in the calibration cavity and the test cavity are uniformly mixed and reach a stable state, record the third pressure P3 and the third temperature T3 of the test cavity. Wherein, the uniform mixing of the gases in the calibration cavity and the test cavity means that the stable state is reached, the pressures in the calibration cavity and the test cavity are in equilibrium, and the pressures in the calibration cavity and the test cavity are the same.

[0064] Step S43: calculate the calculated volume of the test cavity according to the following second formula:

[0065] Wherein, V1 represents the calculated volume of the calibration cavity, unit: m 3 ; V2 represents the calculated volume of the test cavity, unit: m 3 ; P1 represents the first pressure in the calibration cavity before the calibration cavity and the test cavity are connected, unit: Pa; P2 represents the second pressure in the test cavity before the calibration cavity and the test cavity are connected, unit: Pa; P3 represents the third pressure in the test cavity after the calibration cavity and the test cavity are connected, unit: Pa; T1 represents the first temperature in the calibration cavity before the calibration cavity and the test cavity are connected, unit: K; T2 represents the second temperature in the test cavity before the calibration cavity and the test cavity are connected, unit: K; T3 represents the third temperature in the test cavity after the calibration cavity and the test cavity are connected, unit: K. In actual measurement, considering the influence of the internal volume of the pipeline, the calculated volume of the calibration cavity represented by V1 should be understood as the sum of the internal volume of the calibration cavity and the pipeline connected thereto, and similarly, the calculated volume of the test cavity represented by V2 should be understood as the sum of the internal volume of the test cavity and the pipeline connected thereto. Read the first pressure sensor reading of the calibration cavity, i.e. the first pressure P1 and the first temperature sensor reading, i.e. the first temperature T1, according to the ideal gas state equation: P1V1=N1RT1

[0066] Wherein, P1 represents the first pressure in the calibration cavity before the calibration cavity and the test cavity are connected, unit: Pa; V1 represents the calculated volume of the calibration cavity, unit: m 3 ; N1 represents the number of moles of gas in the calibration cavity before the calibration cavity and the test cavity are connected, unit: mol; R represents the molar gas constant, taking 8.31 J / mol / K; T1 represents the first temperature in the calibration cavity before the calibration cavity and the test cavity are connected, unit: K.

[0067] The second pressure sensor in the test cavity reads the second pressure P2 and the second temperature sensor reads the second temperature T2, and similarly, P2V2=N2RT2

[0068] Wherein, P2 represents the second pressure in the test cavity before the calibration cavity and the test cavity are connected, and the unit is Pa; V2 represents the calculated volume of the test cavity, and the unit is m 3 N2 represents the number of moles of gas in the test cavity before the calibration cavity and the test cavity are connected, and the unit is mol; T2 represents the second temperature in the test cavity before the calibration cavity and the test cavity are connected, and the unit is K.

[0069] The first valve is opened, and the gas in the test cavity and the calibration cavity will be mixed quickly, and when the pressure and temperature readings are stable, the second pressure sensor in the test cavity reads the third pressure P3 and the second temperature sensor reads the third temperature T3. Similarly, P3(V1+V2)=(N1+N2)RT3

[0070] Wherein, P3 represents the third pressure in the test cavity after the calibration cavity and the test cavity are connected, and the unit is Pa; T3 represents the third temperature in the test cavity after the calibration cavity and the test cavity are connected, and the unit is K.

[0071] According to the above three formulas, the second formula can be obtained, and the calculated volume V2 of the test cavity is obtained according to the following second formula:

[0072] In the calibration method of the volume measuring device, the first pressure sensor on the calibration cavity measures the pressure inside the calibration cavity and the pipeline connected thereto; the second pressure sensor on the test cavity measures the pressure inside the test cavity and the pipeline connected thereto. The first temperature sensor on the calibration cavity measures the temperature inside the calibration cavity and the pipeline connected thereto; the second temperature sensor on the test cavity measures the temperature inside the test cavity and the pipeline connected thereto.

[0073] The inside of the calibration cavity can be equipped with a first temperature control component, and the inside of the detection piece is equipped with a second temperature control component, so that the temperature of the calibration cavity can be controlled to be the same as the temperature of the test cavity, and a constant temperature environment during the entire test process is maintained, that is, T1=T2=T3.

[0074] Therefore, the third formula can be obtained, and the calculated volume V2 of the test cavity is obtained according to the following third formula:

[0075] In the embodiment, when the calculation volume of the test cavity is calibrated by using the calibration cavity, the first pressure P1 in the calibration cavity is not less than 2 times of the second pressure P2 in the test cavity, and the first pressure P1 in the calibration cavity is not more than 10,000 times of the second pressure P2 in the test cavity. After the calibration cavity is communicated with the test cavity, the pressure change of the test cavity can be clearly perceived and accurately displayed by the second pressure sensor.

[0076] As a preferred embodiment, the sum of the internal volume of the calibration cavity 21 and the pipeline communicated with the calibration cavity 21 is greater than or equal to 1 / 10 of the sum of the internal volume of the test cavity 11 and the pipeline communicated with the test cavity 11, and the sum of the internal volume of the calibration cavity 21 and the pipeline communicated with the calibration cavity 21 is less than or equal to 2 times of the sum of the internal volume of the test cavity 11 and the pipeline communicated with the test cavity 11.

[0077] In the embodiment, in order to accurately calibrate the calculation volume of the test cavity 11, the volume in the calibration cavity 21 and the pipeline communicated with the calibration cavity 21 should not be too small, otherwise, after the calibration cavity 21 is communicated with the test cavity 11, the pressure change of the test cavity 11 is too small, and the numerical change of the second pressure sensor 12 is too small, which increases the calculation error of the calculation volume of the test cavity 11. Therefore, the sum of the volume in the calibration cavity 21 and the pipeline communicated with the calibration cavity 21 should be not less than 1 / 10 of the sum of the volume in the test cavity 11 and the pipeline communicated with the test cavity 11. By limiting the calculation volume of the calibration cavity 21, the present disclosure avoids the problem that the measurement error is too large due to the too small calculation volume of the calibration cavity 21, and improves the accuracy of the test result of the gas leakage rate of the to-be-tested pipeline 31. In addition, the sum of the volume in the calibration cavity 21 and the pipeline communicated with the calibration cavity 21 should be not more than 2 times of the sum of the volume in the test cavity 11 and the pipeline communicated with the test cavity 11, which can avoid the increase of the processing difficulty and cost of the equipment due to the too large calculation volume of the calibration cavity 21.

[0078] The non-metal hydrogen delivery pipeline gas leakage rate testing device provided by the present disclosure comprises the volume measuring device of any one of the above embodiments, and a leakage rate testing unit. The volume measuring device is configured to measure the calculated volume of the test cavity 11; the leakage rate testing unit is configured to, in the case that the second gas injection assembly 8 in the volume measuring device injects the second set pressure gas into the pipeline to be tested 31, and the gas leakage in the pipeline to be tested 31 reaches equilibrium, obtain the pressure change value of the test cavity 11 within a preset time interval, and calculate the gas leakage rate of the pipeline to be tested 31 based on the preset time interval, the pressure change value, and the calculated volume of the test cavity 11 and the current temperature in the test cavity 11. The preset time interval can be any time interval after the gas leakage in the pipeline to be tested 31 reaches equilibrium, and can be calibrated according to the actual measurement. It should be understood that when the gas leakage in the pipeline to be tested 31 reaches equilibrium, the slope of the pressure change curve in the test cavity 11 remains unchanged, so the gas leakage in the pipeline to be tested 31 can be determined according to the change of the slope of the pressure change curve in the test cavity 11. In the case that the gas leakage in the pipeline to be tested 31 reaches equilibrium, a time interval can be preset, and the pressure change value within the preset time interval is recorded. The calculated volume of the test cavity 11 is measured by the volume measuring device described above. The measurement of the calculated volume of the test cavity 11 can be performed before the gas leakage rate test, or after the gas leakage in the pipeline to be tested 31 reaches equilibrium, after the gas leakage rate test, and then the calculated volume of the test cavity 11 is measured. The current temperature in the test cavity 11 refers to the temperature in the test cavity 11 after the gas leakage in the pipeline to be tested 31 reaches equilibrium. The measurement time of the second temperature and the third temperature is different, and the value can also be different. However, if the second temperature control assembly 14 is provided in the test cavity 11 to always control the temperature in the test cavity 11 to remain constant, the current temperature in the test cavity 11 is the same as the second temperature and the third temperature.

[0079] When the gas leakage rate test of the pipeline to be tested 31 or the measurement of the calculated volume of the test cavity 11 is required, the two ends of the pipeline to be tested 31 are sealed and placed in the detection piece 1, and the detection piece 1 is sealed. At this time, the test cavity 11 is formed in the detection piece 1, the pipeline to be tested 31 is inflated by the second gas injection assembly 8, and the pipeline to be tested 31 is inflated to the second set pressure. After the gas leakage in the pipeline to be tested 31 reaches equilibrium, the pressure change value of the test cavity 11 within a preset time interval is obtained, and the gas leakage rate of the pipeline to be tested 31 is calculated based on the preset time interval, the pressure change value within the preset time interval, the calculated volume of the test cavity 11, and the current temperature in the test cavity 11.

[0080] Specifically, the leakage rate testing unit calculates the gas leakage rate of the pipeline to be tested based on the following first formula:

[0081] Wherein, J represents the gas leakage rate, ΔP is the pressure change value, Δt is the preset time interval, V2 is the calculated volume of the test cavity, R is the molar gas constant, T is the current temperature in the test cavity, and L is the length of the pipeline to be tested.

[0082] As a preferred embodiment, the non-metal hydrogen pipeline gas leakage rate testing device further comprises a gas extraction system in selective communication with the test cavity 11 and the pipeline to be tested 31, and configured to extract the gas in the test cavity 11 and the pipeline to be tested 31. The gas extraction system is provided with a gas extraction pipe between the detection member 1 and the pipeline to be tested 31, and a valve is arranged on the gas extraction pipe. When the gas in the detection member 1 needs to be extracted, the valve between the gas extraction system and the test cavity 11 is opened, and the vacuum pump is started to extract the gas in the detection member 1. When the gas in the pipeline to be tested 31 needs to be extracted, the valve between the gas extraction system and the pipeline to be tested 31 is opened, and the vacuum pump is started to extract the gas in the pipeline to be tested 31.

[0083] Specifically, when the gas leakage rate of the pipeline to be tested 31 is tested, the pipeline to be tested 31 and the test cavity 11 are first extracted by the gas extraction system to ensure that the airtightness of the test cavity 11 and the pipeline to be tested 31 is good. Then, the second high-pressure gas source 81 and the pipeline to be tested 31 are connected, the pipeline to be tested 31 is inflated by the second high-pressure gas source 81, and the pipeline to be tested 31 is inflated to the second set pressure. Then, the gas leakage rate of the pipeline to be tested 31 can be tested. It should be understood that the pipeline to be tested 31 and the test cavity 11 can be extracted at the same time, or the pipeline to be tested 31 and the test cavity 11 can be extracted respectively, and the present disclosure is not limited thereto.

[0084] The detection piece 1 in the present disclosure has a cavity structure inside which can accommodate the pipeline 31 to be tested. When the pipeline 31 to be tested is placed in the detection piece 1, the gas leakage of the pipeline 31 to be tested is measured by measuring the calculation volume of the test cavity 11 and the pressure change. It should be understood that the detection cavity 16 in the detection piece 1 can accommodate the pipeline 31 to be tested in any shape, so that the test cavity 11 formed in the detection piece 1 is in any shape. As long as the pipeline 31 to be tested can be accommodated in the detection cavity 16 of the detection piece 1, the calculation volume of the test cavity 11 can be measured, and the gas leakage rate of the pipeline 31 to be tested can be measured. That is, the internal space of the detection piece 1 can be adapted to the pipeline 31 to be tested in any shape. When the pipeline 31 to be tested is located in the detection piece 1, the calculation volume of the test cavity 11 is accurately calculated by measuring the pressure and temperature change in the test cavity 11, and the gas leakage rate of the pipeline 31 to be tested is measured, thereby improving the accuracy of the pipeline gas leakage rate test results. And avoid the difficulty of volume measurement caused by complex structure and structure cooperation, so as to not only realize the measurement of different diameter specifications, different shapes of non-metal pipelines with one set of equipment, but also realize the gas leakage rate test of various joint structures such as live fusion joint, hot fusion joint or mechanical flange joint.

[0085] As a preferred embodiment, the gas extraction system includes a first gas extraction system and a second gas extraction system. The first gas extraction system is in selective communication with the detection piece 1, and the second gas extraction system is in selective communication with the pipeline 31 to be tested. The first gas extraction 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 piece 1. The second gas extraction 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 31 to be tested, and the fourth valve 73 is located outside the detection piece 1. Opening the third valve 71 and starting the first vacuum pump 72 can extract the vacuum of the detection piece 1, ensure the good airtightness of the detection piece 1, and ensure the accuracy of the subsequent measurement data. Opening the fourth valve 73 and starting the second vacuum pump 74 can extract the vacuum of the pipeline 31 to be tested, ensure the good airtightness of the pipeline 31 to be tested, and ensure the accuracy of the subsequent measurement data.

[0086] In one specific embodiment, one end of the pipeline 31 to be tested is connected with a pipeline which extends through the side wall of the detection piece 1 by the pipeline 31 to be tested, and is in communication with the second high-pressure gas source 81 and the second vacuum pump 74 through a three-way pipe fitting joint. A valve is arranged between the three-way pipe fitting joint and the second high-pressure gas source 81 to control the communication relationship between the second high-pressure gas source 81 and the pipeline 31 to be tested. The fourth valve 73 is arranged between the three-way pipe fitting joint and the second vacuum pump 74 to control the communication relationship between the pipeline 31 to be tested and the second vacuum pump 74.

[0087] As a preferred embodiment, the non-metallic hydrogen pipeline gas leakage rate testing device further comprises a waste gas treatment system 75, which is arranged between and communicates with the first vacuum pump 72 and the second vacuum pump 74. The waste gas treatment system 75 is arranged to recycle the gas extracted from the detection piece 1 and the pipeline 31 to be tested.

[0088] In the present disclosure, after the pipeline to be tested is placed in the detection piece 1, the detection piece 1 is sealed, the fourth valve 73 is first opened, and the second vacuum pump 74 of the second gas extraction system performs vacuumization on the pipeline 31 to be tested; the third valve 71 is opened, and the first vacuum pump 72 of the first gas extraction system performs vacuumization on the detection piece 1. Then, the valve between the second high-pressure gas source 81 and the pipeline 31 to be tested is opened, and the second high-pressure gas source 81 starts to inflate the pipeline 31 to be tested. When the pressure of the pipeline 31 to be tested reaches the second set pressure, the valve is closed. The gas leakage rate test of the pipeline 31 to be tested is performed. It should be understood that the vacuumization process of the pipeline 31 to be tested by the second vacuum pump 74 can be completed before the pipeline 31 to be tested is placed in the detection piece 1, or can be completed after the pipeline 31 to be tested is placed in the detection piece 1, as long as it is performed before the pipeline 31 to be tested is inflated by the second high-pressure gas source 81.

[0089] As a preferred embodiment, the gas leakage rate testing device for non-metallic hydrogen pipeline further comprises a support seat 32, which is arranged in the detection piece 1 and is movable, and the pipeline 31 to be tested is placed on the support seat 32. It should be understood that the movement of the support seat 32 in the detection piece 1 can be realized by the following ways: the bottom of the support seat 32 is provided with a roller; or, a slide rail is arranged in the detection piece 1, and the bottom of the support seat 32 is provided with a pulley and the like which can make the support seat 32 loaded with the pipeline 31 to be tested enter the detection piece 1 stably and conveniently.

[0090] Wherein, the pipeline 31 to be tested also has a sealing piece 33 at each end, which is used to seal the pipeline 31 to be tested to prevent the gas in the pipeline 31 to be tested from leaking due to poor sealing. When the pipeline 31 to be tested is located in the detection piece 1, the detection piece 1 has the pipeline 31 to be tested, the support seat 32, other components connected with the support seat 32, and the pipeline connected with the pipeline 31 to be tested, and the test cavity 11 is the cavity in the detection piece 1 occupied by the components not contained in the detection piece 1.

[0091] As a preferred embodiment, at least one side of the detection piece 1 has an opening for the pipeline 31 to be tested to enter the detection piece 1, and the opening has a detachable end seal. At least one opening is provided on the detection piece 1 for loading the pipeline 31 to be tested into the detection piece 1. After the pipeline 31 to be tested enters the detection piece 1, the opening of the detection piece 1 is sealed with the end seal, which ensures that the gas in the detection piece 1 will not leak, resulting in inaccurate test parameters.

[0092] As a preferred embodiment, the non-metal hydrogen pipeline gas leakage rate testing device further comprises a pad 34 arranged at the bottom of the detection piece 1 for supporting the detection piece 1. The pad 34 is used to support the entire testing device and ensure the movement and stability of the entire testing device.

[0093] The present disclosure also provides a method for testing the gas leakage rate of a non-metal hydrogen pipeline, which uses the non-metal hydrogen pipeline gas leakage rate testing device of any one of the above embodiments. The testing method comprises the following steps:

[0094] Step S1: After placing the pipeline to be tested in the detection cavity 16 to form a sealed test cavity, the test cavity is evacuated. The two ends of the pipeline to be tested are sealed with a seal, the pipeline to be tested is loaded into the detection piece from the opening of the detection piece, and the opening of the detection piece is sealed with an end seal. Specifically, after the pipeline to be tested is placed in the detection piece, the detection piece is sealed, the pipelines are connected, and the entire testing device is checked for air tightness. The test cavity in the detection piece is evacuated. It is very important to ensure that the air tightness of the entire testing device is good, so that the subsequent data measurement in the test cavity is accurate.

[0095] Step S2: Discharge the air in the pipeline to be tested and inject a second set pressure gas into the pipeline to be tested. That is, before inflating the pipeline to be tested, the gas in the pipeline to be tested is first discharged, and then the pipeline to be tested is inflated by a second high-pressure gas source. In another embodiment, the air in the pipeline to be tested can also not be discharged before inflating the pipeline to be tested.

[0096] It should be understood that step S2 can be before step S1, that is, first seal the two ends of the pipeline to be tested with the sealing member, first exhaust the air in the pipeline to be tested, then inflate the pipeline to be tested by the second high-pressure gas source and inflate to the second set pressure, then place the pipeline to be tested in the detection member, and seal the opening of the detection member with the end sealing member, so that the test cavity is formed in the detection member. Alternatively, step S2 is after step S1, that is, first seal the two ends of the pipeline to be tested with the sealing member, then place the pipeline to be tested in the detection member, and seal the opening of the detection member with the end sealing member, so that the test cavity is formed in the detection member. Then exhaust the air in the pipeline to be tested, then inflate the pipeline to be tested by the second high-pressure gas source and inflate to the second set pressure. Preferably, step S2 is after step S1.

[0097] Specifically, after the two ends of the pipeline to be tested 31 are sealed, the second vacuum pump 74 can perform vacuumization on the pipeline to be tested 31, then perform the air tightness test, and after determining that the air tightness of the pipeline to be tested 31 is good, place the pipeline to be tested 31 in the detection member, seal the detection member, and then inflate the pipeline to be tested 31 by the second high-pressure gas source 81; or, after vacuumizing the pipeline to be tested 31 and determining that the air tightness is good, inflate the pipeline to be tested 31 by the second high-pressure gas source 81, then place the pipeline to be tested 31 in the detection member 1, and seal the detection member 1; or, after sealing the two ends of the pipeline to be tested 31, place the pipeline to be tested 31 in the detection member 1, and seal the detection member 1, then vacuumize the pipeline to be tested 31, determine that the air tightness of the pipeline to be tested 31 is good, and then inflate the pipeline to be tested 31 by the second high-pressure gas source 81.

[0098] Step S3: When the gas leakage of the pipeline to be tested 31 reaches equilibrium, the pressure change value of the test cavity 11 in a preset time interval is obtained, and the gas leakage rate of the pipeline to be tested 31 is calculated based on the preset time interval, the pressure change value, and the calculated volume of the test cavity 11, the current temperature in the test cavity 11. When the pressure change rate in the pipeline to be tested 31 also tends to be stable, that is, the slope of the pressure change-time curve in the pipeline to be tested 31 remains unchanged, the gas leakage in the pipeline to be tested 31 reaches equilibrium, at this time a preset time interval is set, and the pressure change value in the preset time interval is recorded, that is, the initial pressure of the test cavity 11 at the initial time and the final pressure of the test cavity at the end time in the preset time interval are recorded, and then the pressure difference between the initial time and the end time of the preset time interval is calculated. Preferably, the pipeline to be tested 31 is placed in the detection piece 1 and inflated to the second set pressure by the second high-pressure gas source 81 and the fourth pipeline 82, and the gas in the pipeline to be tested 31 starts to leak, and after the gas leakage in the pipeline to be tested 31 reaches equilibrium, a preset time interval Δt is set, the initial pressure of the test cavity 11 at the initial time is recorded; Δt time is the end time, and the final pressure of the test cavity 11 at the end time is recorded, and the pressure difference of the test cavity 11 between the initial time and the end time is obtained.

[0099] Then the gas leakage rate of the pipeline to be tested is calculated by the first formula:

[0100] Wherein, J represents the gas leakage rate of the pipeline to be tested, with the unit of mol / m / s; ΔP is the pressure change value of the test cavity in the time interval Δt, with the unit of P a ; Δt is the preset time interval; V2 is the calculated volume of the test cavity, with the unit of m 3 ; R is the molar gas constant, with the value of 8.31, with the unit of J / mol / K; T is the current temperature in the test cavity, with the unit of K; L is the length of the pipeline to be tested, with the unit of m.

[0101] The calculation of the volume of the test cavity 11 using the calibration cavity 21 can be before step S3 or also after step S3. Specifically, the calculation of the volume of the test cavity 11 using the calibration cavity 21 can be before step S3, that is, after the pipeline to be tested 31 is placed in the detection piece 1 and before the second high-pressure gas source 81 inflates the pipeline to be tested 31. Alternatively, the calculation of the volume of the test cavity 11 using the calibration cavity 21 is at any time point after the second high-pressure gas source 81 inflates the pipeline to be tested 31 and before the pressure change rate of the test cavity 11 tends to be stable. Alternatively, the calculation of the volume of the test cavity 11 using the calibration cavity 21 is after step S3, that is, after the gas leakage rate of the pipeline to be tested 31 reaches an equilibrium state and the pressure change rate of the test cavity 11 also tends to be stable, and the pipeline to be tested 31 is still sealed in the detection piece 1 and has not been taken out. That is, in the non-metallic hydrogen pipeline gas leakage rate test method of the present disclosure, the calculation of the volume of the test cavity 11 can be performed before and after the non-metallic hydrogen pipeline gas leakage test using the steps of the non-metallic hydrogen pipeline gas leakage rate test method of the present disclosure. It should be understood that if the calculation of the volume of the test cavity 11 is performed before the non-metallic hydrogen pipeline gas leakage test, the calculation of the volume of the test cavity 11 does not take into account the effect of the expansion of the pipeline to be tested 31 on the calculation of the volume of the test cavity 11, and the measurement result of the calculation of the volume of the test cavity 11 has an error; if the calculation of the volume of the test cavity 11 is performed after the non-metallic hydrogen pipeline gas leakage test, the calculation of the volume of the test cavity 11 takes into account the effect of the expansion of the pipeline to be tested 31 on the calculation of the volume of the test cavity 11, so that the calculation of the volume of the test cavity 11 is more accurate, and the determination of the gas leakage rate of the pipeline to be tested is more accurate.

[0102] The present disclosure also provides a non-metallic pipeline volume expansion amount test method, which is applied to the non-metallic hydrogen pipeline gas leakage rate test device of any one of the above embodiments, and the method comprises: before the gas leakage rate test, the measurement unit calculates the first volume of the test cavity based on the following second formula:

[0103] Wherein, V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, 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-metal pipeline gas leakage rate test is performed; after the test is completed, the measuring unit calculates the calculated volume of the test cavity according to the second formula as a second volume, and calculates the volume expansion of the non-metal pipeline based on the difference between the first volume and the second volume. Before the pipeline leakage rate test, the calculated volume of the test cavity is measured, and the calculated volume of the test cavity calculated according to the second formula is the first volume; after the pipeline leakage rate test, the calculated volume of the test cavity is measured, and the second volume of the test cavity calculated according to the second formula is calculated, and the difference between the first volume and the second volume is calculated to obtain the volume expansion of the pipeline to be tested.

[0104] In one embodiment of the present disclosure, the pipeline to be tested 31 is placed in the detection piece 1 through the opening of the detection piece 1, and then the detection piece 1 is sealed, and the inside of the detection piece 1 forms the test cavity 11. The second valve 223 between the calibration cavity 21 and the first high-pressure gas source 222 is opened, the first high-pressure gas source 222 and the calibration cavity 21 are connected, the calibration cavity 21 is inflated, and the calibration cavity 21 is inflated to a first set pressure, the second valve 223 is closed, the first pressure P1 and the first temperature T1 in the calibration cavity 21 are read, and the second pressure P2 and the second temperature T2 of the test cavity 11 are read. Then, the first valve 6 between the test cavity 11 and the calibration cavity 21 is opened, the calibration cavity 21 and the test cavity 11 are connected, the gas in the calibration cavity 21 and the test cavity 11 is mixed, and after the pressure and temperature in the test cavity 11 are stable, the third pressure P3 and the third temperature T3 of the test cavity 11 at this time are recorded, and then the first volume of the test cavity 11 is obtained according to the second formula.

[0105] Then, the first valve 6 between the calibration cavity 21 and the test cavity 11 is closed, the test cavity 11 is vacuumized by the first vacuum pump 72, and the pipeline to be tested 31 is vacuumized by the second vacuum pump 74. Then, the second gas filling assembly 8 and the pipeline to be tested 31 are connected, the second high-pressure gas source 81 inflates the pipeline to be tested 31 to a second set pressure, and the leakage test of the pipeline to be tested 31 is started. After the hydrogen leakage of the pipeline to be tested 31 reaches a balanced state, the pressure change value in the test cavity within a preset time interval and the current temperature in the test cavity are recorded, and then the leakage rate of the pipeline to be tested 31 is obtained.

[0106] After the leakage rate test of the pipeline to be tested 31 is completed, the measuring unit 9 measures the second volume in the test cavity 11 at this time according to the above-mentioned volume measurement method, and the difference between the first volume and the second volume is calculated to obtain the volume expansion of the pipeline to be tested 31.

[0107] In another embodiment of the present disclosure, the pipeline to be tested 31 is placed into the detection piece 1 through the opening of the detection piece 1, and then the detection piece 1 is sealed, so that the inner wall of the detection piece 1 and the pipeline to be tested 31 form the test cavity 11. The test cavity 11 is vacuumized by the first vacuum pump 72, and the pipeline to be tested 31 is vacuumized by the second vacuum pump 74. Then, the second gas filling assembly 8 and the pipeline to be tested 31 are connected, the pipeline to be tested 31 is filled with gas to a second set pressure, and the leakage test of the pipeline to be tested 31 is started. After the gas leakage of the pipeline to be tested 31 reaches an equilibrium state, the pressure change value of the test cavity within a preset time interval and the current temperature in the test cavity 11 are recorded.

[0108] Then, the second valve 223 between the calibration cavity 21 and the first high-pressure gas source 222 is opened, the first high-pressure gas source 222 and the calibration cavity 21 are connected, the calibration cavity 21 is filled with gas, and is filled to a first set pressure. The second valve 223 is closed, the first pressure P1 and the first temperature T1 in the calibration cavity 21 are read, and the second pressure P2 and the second temperature T2 of the test cavity 11 are read. Then, the first valve 6 between the test cavity 11 and the calibration cavity 21 is opened, the calibration cavity 21 and the test cavity 11 are connected, the gas in the calibration cavity 21 and the test cavity 11 is mixed, and after the pressure and temperature in the test cavity 11 stabilize, the third pressure P3 and the third temperature T3 of the test cavity 11 at this time are recorded. The first valve 6 between the calibration cavity 21 and the test cavity 11 is closed, and the calculated volume of the test cavity 11 is obtained according to the above-mentioned second formula. According to the calculated volume of the test cavity 11 and the pressure change value and temperature within a preset time interval after the gas leakage of the pipeline to be tested 31 reaches an equilibrium state, the gas leakage rate of the pipeline to be tested 31 is obtained.

[0109] In the non-metal hydrogen delivery pipeline gas leakage rate test method of the present disclosure, the first volume of the test cavity 11 can be obtained by measuring the calculated volume of the test cavity 11 before the gas leakage test of the pipeline to be tested 31, and the second volume of the test cavity 11 can be obtained by measuring the calculated volume of the test cavity 11 after the gas leakage test of the pipeline to be tested 31. The volume expansion change of the pipeline to be tested 31, i.e. the difference between the calculated volumes of the test cavity 11 before and after the gas leakage test of the pipeline to be tested 31, is obtained, and then the volume expansion amount of the pipeline to be tested 31 caused by the internal pressure of the pipeline to be tested 31 is obtained. The difficulty of installing a displacement sensor for testing in a small volume and vacuum environment is solved. At the same time, the measurement of the calculated volume of the test cavity 11 can be performed after the gas leakage rate test is completed, without the need to take out the pipeline to be tested 31 from the detection piece 1 for measurement. In this embodiment, the calculated volume of the test cavity 11 takes into account the expansion deformation of the pipeline to be tested 31, and the test result is more accurate.

[0110] The present disclosure takes the non-metal hydrogen pipeline gas leakage rate test as an example to illustrate the specific implementation in the actual application scenario.

[0111] Example 1:

[0112] Taking the polyethylene pipeline with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as an example, the helium leakage test is performed on the pipeline to be tested 31; wherein the calculation volume of the calibration cavity 21 is the sum of the volume in the calibration cavity and the pipeline connected thereto, and the calculation volume is 0.02m 3 , i.e. 20L.

[0113] Before the test, open the second valve 223 to charge the calibration cavity 21, so that the pressure of the calibration cavity 21 reaches 0.21MPa, and the temperature data of the calibration cavity 21 is read by the first temperature sensor 212 arranged on the calibration cavity 21 as 30℃, i.e. 303.15K. Then close the second valve 223, and read the pressure indication of the second pressure sensor 12 of the test cavity 11 as 0.1MPa, and the second temperature sensor 13 indication as 22℃, i.e. 295.15K.

[0114] Open the first valve 6 connecting the calibration cavity 21 and the test cavity 11, so that the gas in the calibration cavity 21 and the test cavity 11 is mixed, and after a period of time, it is observed that the second pressure sensor 12 of the test cavity 11 is stable, and the indication is 0.11MPa, and the second temperature sensor 13 is stable, and the indication is 23℃, i.e. 296.15K.

[0115] According to the above data, the calculation volume of the test cavity 11 before the test can be calculated by the second formula as 0.197m 3 , i.e. 197L.

[0116] Close the first valve 6 connecting the calibration cavity 21 and the test cavity 11, and use the first vacuum pump 72 to vacuum the test cavity 11 to 10Pa, and fill 1MPa of high-pressure pure helium into the pipeline to be tested 31, and start the leakage test.

[0117] After the test, repeat the above steps of charging the calibration cavity 21 before the test, reading the number, and connecting the calibration cavity 21 and the test cavity 11 to mix the gas in the two cavities. Before the gas in the calibration cavity 21 and the test cavity 11 is mixed, the pressure indication of the first pressure sensor 211 arranged on the calibration cavity 21 is 0.195MPa, the temperature data read by the first temperature sensor 212 is 30℃, the pressure indication of the second pressure sensor 12 of the test cavity 11 is 2200Pa, and the indication of the second temperature sensor 13 is 23℃. After the gas in the calibration cavity 21 and the test cavity 11 is mixed, the indication of the second pressure sensor 12 of the test cavity 11 is 19865Pa, and the indication of the second temperature sensor 13 is 24℃.

[0118] According to the above data, the calculated volume of the test cavity 11 after the test is calculated as 0.194m 3 , i.e. 194L.

[0119] Therefore, the pressure caused by helium leakage can be corrected based on the above data, and the volume expansion of the pipeline to be tested 31 can be calculated as 0.003m 3 , i.e. 3L.

[0120] Example 2:

[0121] Take the polyethylene pipeline to be tested 31 with an outer diameter of 110mm, a wall thickness of 10mm, and a length of 1000mm as an example, and test the hydrogen leakage of the pipeline to be tested 31; wherein the calculated volume of the calibration cavity 21 is the sum of the volume of the calibration cavity and the pipeline connected thereto, and the calculated volume is 0.02m 3 , i.e. 20L.

[0122] Before the test, open the second valve to charge the calibration cavity 21, so that the pressure of the calibration cavity 21 reaches 0.21MPa, and the temperature data of the calibration cavity 21 is read by the first temperature sensor 212 arranged on the calibration cavity 21 as 30℃, i.e. 303.15K. Then close the second valve, and read the pressure indication of the second pressure sensor 12 of the test cavity 11 as 0.1MPa, and the indication of the second temperature sensor 13 as 22℃, i.e. 295.15K.

[0123] Open the first valve 6 connecting the calibration cavity 21 and the test cavity 11, so that the gas in the calibration cavity 21 and the test cavity 11 is mixed, and after a period of time, it is observed that the indication of the second pressure sensor 12 of the test cavity 11 is stable, which is 0.11MPa, and the indication of the second temperature sensor 13 is stable, which is 23℃, i.e. 296.15K.

[0124] According to the above data, the calculated volume of the test cavity 11 before the test can be calculated by the second formula as 0.197m 3 , i.e. 197L.

[0125] Close the first valve 6 connecting the calibration cavity 21 and the test cavity 11, and use the first vacuum pump 72 to vacuum the test cavity 11 to 10Pa, and fill 1MPa of high-pressure pure hydrogen into the pipeline to be tested 31, and start the leakage test.

[0126] After the test, the above steps of charging the calibration cavity 21, reading, and connecting the calibration cavity 21 and the test cavity 11 to mix the gases in the two cavities are repeated. Before the gases in the calibration cavity 21 and the test cavity 11 are mixed, the pressure reading of the first pressure sensor 211 provided on the calibration cavity 21 is 0.195 MPa, the temperature reading of the first temperature sensor 212 is 30℃, the pressure reading of the second pressure sensor 12 of the test cavity 11 is 2000 Pa, and the reading of the second temperature sensor 13 is 23℃. After the gases in the calibration cavity 21 and the test cavity 11 are mixed, the pressure reading of the second pressure sensor 12 of the test cavity 11 is 19680 Pa, and the reading of the second temperature sensor 13 is 24℃.

[0127] According to the above data, the calculated volume of the test cavity 11 after the test is calculated to be 0.194 m 3 , i.e. 194 L.

[0128] Therefore, the pressure caused by hydrogen leakage can be corrected based on the above data, and the volume expansion of the test pipeline 31 can be calculated to be 0.003 m 3 , i.e. 3 L.

[0129] Example 3

[0130] The test pipeline 31 is taken as an example of a polyethylene pipeline with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm. If the calibration cavity 21 is not used to calibrate the calculated volume of the test cavity 11, the calculated volume of the test cavity 11 is 183 L according to the geometric dimensions of the detection member 1, the test pipeline 31, and the test pipeline end sealing member. After the hydrogen leakage of the non-metal pipeline reaches equilibrium, the pressure reading of the second pressure sensor 12 of the test cavity 11 increases from 1200 Pa to 2000 Pa within a 1-hour time interval, and the reading of the second temperature sensor 13 is 23℃. At this time, the calculated hydrogen leakage rate of the non-metal pipeline is 1.65 x 10 -5 mol / m / s.

[0131] The calculated volume of the calibration cavity 21 of the present disclosure is the sum of the volumes in the calibration cavity 21 and the pipeline connected thereto, which is 0.02 m 3, i.e. 20 L. After the non-metal pipeline hydrogen leakage rate test is completed, the calculation volume of the test cavity 11 is calibrated by using the calibration cavity 21. The pressure reading of the first pressure sensor 211 arranged on the calibration cavity 21 is 0.195 MPa, the temperature data of the first temperature sensor 212 is 30°C, the pressure reading of the second pressure sensor 12 of the test cavity 1 is 2000 Pa, and the reading of the second temperature sensor 13 is 23°C. After the calibration cavity 21 is communicated with the test cavity 11, the reading of the second pressure sensor 12 of the test cavity 11 is 19680 Pa, and the reading of the second temperature sensor 13 is 24°C. Thus, the calculation volume of the test cavity 11 after the test is calculated as 0.194 m 3 , i.e. 194 L. At this time, the calculated non-metal pipeline hydrogen leakage rate is 1.75 x 10 -5 mol / m / s.

[0132] It can be seen that, if the volume measuring device and method of the present disclosure are not used, the result of the non-metal pipeline hydrogen leakage rate test will have an error of (1.75 x 10 -5 - 1.65 x 10 -5 ) / 1.75 x 10 -5 = 5.7%.

[0133] Example 4:

[0134] Taking the polyethylene pipeline with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm as the pipeline to be tested 31, the hydrogen leakage of the pipeline to be tested 31 is tested. The calculation volume of the test cavity 11 is calibrated by using the calibration cavity 21. The calculation volume of the calibration cavity 21 is the sum of the volumes in the calibration cavity 21 and the pipeline connected thereto, which is 0.02 m 3 , i.e. 20 L. According to the calculation of Example 1, the calculation volume of the test cavity before the hydrogen leakage test of the pipeline to be tested 31 is 197 L. If the calculation volume of the test cavity 11 before the hydrogen leakage test of the pipeline to be tested 31 is used to calculate the pipeline hydrogen leakage rate (i.e. without considering the expansion deformation of the non-metal pipeline during the test), the calculated non-metal pipeline hydrogen leakage rate is 1.78 x 10 -5 mol / m / s.

[0135] By using the volume measuring device and method of the present disclosure, the calculation volume of the test cavity is measured again after the hydrogen leakage test of the pipeline to be tested (i.e. considering the expansion deformation of the non-metal pipeline during the test), which is 194 L. At this time, the calculated non-metal pipeline hydrogen leakage rate is 1.75 x 10 -5 mol / m / s.

[0136] It can be seen that if the expansion deformation of the non-metal pipeline during the test is not considered, the result of the hydrogen leakage test of the non-metal pipeline will have an error of 1.78 x 10 -5 -1.75 x 10 -5 ) / 1.75 x 10 -5 = 1.7%.

[0137] Example 5

[0138] The pipeline 31 to be tested is taken as a polyethylene pipeline with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm. The hydrogen leakage test is performed on the pipeline 31 to be tested. The first temperature control assembly 23 and the second temperature control assembly 14 are respectively installed in the calibration cavity 21 and the test cavity 11, so that the entire test process is in a constant temperature environment. The calculation volume of the calibration cavity 21 is the sum of the volume of the calibration cavity 21 and the volume of the pipeline connected thereto, which is 0.02 m 3 , i.e. 20 L.

[0139] The second valve 223 is opened to charge the calibration cavity 21, so that the pressure of the calibration cavity 21 reaches 0.21 MPa. Then the second valve 223 is closed, and the pressure reading of the second pressure sensor 12 of the test cavity 11 is 0.1 MPa. The first valve 6 connected between the calibration cavity 21 and the test cavity 11 is opened, so that the gas in the calibration cavity 21 and the test cavity 11 is mixed. After a period of time, it is observed that the reading of the second pressure sensor 12 of the test cavity 11 is stable, which is 0.11 MPa.

[0140] Using the above data, the calculation volume of the test cavity 11 can be calculated according to the following third formula:

[0141] The calculation volume of the test cavity 11 is 0.02 m 3 , i.e. 20 L.

[0142] Example 6

[0143] The pipeline 31 to be tested is taken as a polyethylene pipeline with an outer diameter of 110 mm, a wall thickness of 10 mm, and a length of 1000 mm. The calculation volume of the test cavity 11 can be repeatedly measured. The calculation volume of the calibration cavity 21 is the sum of the volume of the calibration cavity 21 and the volume of the pipeline connected thereto, which is 0.02 m 3 , i.e. 20 L.

[0144] With the constant temperature test environment as an example, the second valve 223 is opened to charge the calibration cavity 21, so that the pressure of the calibration cavity 21 reaches 0.32 MPa; then the second valve 223 is closed, and the pressure reading of the second pressure sensor 12 of the test cavity 11 is 0.1 MPa; the first valve 6 connected between the calibration cavity 21 and the test cavity 11 is opened, so that the gas in the calibration cavity 21 and the test cavity 11 is mixed, and after a period of time, it is observed that the reading of the second pressure sensor 12 of the test cavity 11 is stable, which is 0.12 MPa. It can be calculated that the calculated volume of the test cavity 11 is 0.02 m 3 , that is, 20 L.

[0145] The above steps are repeated, the pressure of the calibration cavity 21 is set to 0.64 MPa, the pressure reading of the test cavity 11 is 0.1 MPa, and after the gas in the calibration cavity 21 and the test cavity 11 is mixed, the pressure reading of the second pressure sensor 12 of the test cavity 11 is 0.15 MPa. It can be calculated that the calculated volume of the test cavity 11 is 0.196 m 3 , that is, 196 L.

[0146] The calculated volumes of the test cavities measured in the above two times are averaged, so that the calculated volume of the test cavity is 0.198 m 3 , that is, 198 L. Of course, more accurate values of the calculated volume of the test cavity 11 can be obtained by repeating the above steps more times.

[0147] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not used to limit the protection scope of the present disclosure. It is particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A gas permeation rate testing device for non-metallic hydrogen transport pipes, characterized by, The utility model relates to a kind of gas leakage rate test device, including: Detection piece, the detection piece is formed with the detection cavity suitable for placing the pipeline to be tested, wherein, after the pipeline to be tested is placed in the detection cavity, the sealed test cavity is formed; Calibration cavity, the calibration cavity is selectively communicated with the test cavity; First aeration assembly, the first aeration assembly is selectively communicated with the calibration cavity, to be suitable for the gas of first set pressure is injected into the calibration cavity; Second aeration assembly, the second aeration assembly is selectively communicated with the pipeline to be tested, to be suitable for the gas of second set pressure is injected into the pipeline to be tested; Measurement unit, configured to measure the pressure and temperature in the calibration cavity and the pressure and temperature in the test cavity, and calculate the calculated volume of the test cavity based on the first pressure and first temperature in the calibration cavity before the calibration cavity is communicated with the test cavity, the second pressure and second temperature in the test cavity, and the third pressure and third temperature in the test cavity after the pipeline to be tested leaks balance; Leakage rate test unit, the leakage rate test 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 based on the preset time interval, the pressure change value, the current temperature in the test cavity and the calculated volume of the test cavity after the pipeline to be tested leaks balance; The measurement unit calculates the calculated volume of the test chamber based on the following second formula: Wherein, V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, 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 apparatus of claim 1, wherein The leakage rate test unit calculates the gas leakage rate of the pipe to be tested based on the following first formula: Wherein, J represents the gas leakage rate, ΔP is the pressure change value, Δt is the preset time interval, V2 is the calculated volume of the test cavity, R is the molar gas constant, T is the current temperature in the test cavity, and L is the length of the pipeline to be tested.

3. The gas leak rate testing device of claim 1, wherein, The measurement unit includes: First temperature sensor and first pressure sensor corresponding to the calibration cavity are arranged; Second temperature sensor and second pressure sensor corresponding to the test cavity are arranged.

4. The gas leakage rate testing apparatus of claim 1, wherein The measurement unit further includes: First temperature control assembly corresponding to the calibration cavity is arranged, and second temperature control assembly corresponding to the test cavity is arranged, and the first temperature control assembly and the second temperature control assembly are used to adjust the second temperature to keep the same as the first temperature.

5. The gas leak rate testing device of claim 2, wherein, The measurement unit further includes: First temperature control assembly corresponding to the calibration cavity is arranged, and second temperature control assembly corresponding to the test cavity is arranged, and the first temperature control assembly and the second temperature control assembly are used to adjust the second temperature to keep the same as the first temperature.

6. The gas leak rate testing device of claim 3, wherein, The measurement unit further includes: First temperature control assembly corresponding to the calibration cavity is arranged, and second temperature control assembly corresponding to the test cavity is arranged, and the first temperature control assembly and the second temperature control assembly are used to adjust the second temperature to keep the same as the first temperature.

7. The gas leakage rate testing device of claim 4, wherein V1 represents a calculated volume of the calibration cavity, V2 represents a calculated volume of the test cavity, P1 represents the first pressure, P2 represents the second pressure, and P3 represents the third pressure. In the case that the first temperature and the second temperature remain the same, the measuring unit calculates the calculated volume of the test cavity based on a third formula as follows:

8. The gas leakage rate testing device of claim 5, wherein V1 represents a calculated volume of the calibration cavity, V2 represents a calculated volume of the test cavity, P1 represents the first pressure, P2 represents the second pressure, and P3 represents the third pressure.

9. The gas leakage rate testing device of claim 6, wherein V1 represents a calculated volume of the calibration cavity, V2 represents a calculated volume of the test cavity, P1 represents the first pressure, P2 represents the second pressure, and P3 represents the third pressure. In the case that the first temperature and the second temperature remain the same, the measuring unit calculates the calculated volume of the test cavity based on a third formula as follows:

10. The gas leakage rate testing device of claim 1, wherein a sum of an internal volume of the calibration cavity and a pipeline connected thereto is greater than or equal to 1 / 10 of a sum of an internal volume of the test cavity and a pipeline connected thereto, and the sum of the internal volume of the calibration cavity and the pipeline connected thereto is less than or equal to 2 times the sum of the internal volume of the test cavity and the pipeline connected thereto.

11. The gas leakage rate testing device of claim 1, wherein a sum of an internal volume of the calibration cavity and a pipeline connected thereto is greater than or equal to 1 / 10 of a sum of an internal volume of the test cavity and a pipeline connected thereto, and the sum of the internal volume of the calibration cavity and the pipeline connected thereto is less than or equal to 2 times the sum of the internal volume of the test cavity and the pipeline connected thereto. In the case that the first temperature and the second temperature remain the same, the measuring unit calculates the calculated volume of the test cavity based on a third formula as follows:

12. The gas leakage rate testing device of claim 1, wherein a sum of an internal volume of the calibration cavity and a pipeline connected thereto is greater than or equal to 1 / 10 of a sum of an internal volume of the test cavity and a pipeline connected thereto, and the sum of the internal volume of the calibration cavity and the pipeline connected thereto is less than or equal to 2 times the sum of the internal volume of the test cavity and the pipeline connected thereto.

10. The gas leak rate testing device of claim 1, wherein, 13. The gas leakage rate testing device of claim 1, wherein the pipeline to be tested comprises a non-metal pipeline and a connecting joint connected to the non-metal pipeline, and the connecting joint is any one of a hot melt joint, an electric melt joint, and a mechanical joint.

11. The gas leak rate testing device of claim 2, wherein, 14. The gas leakage rate testing device of claim 1, wherein the pipeline to be tested comprises a non-metal pipeline and a connecting joint connected to the non-metal pipeline, and the connecting joint is any one of a hot melt joint, an electric melt joint, and a mechanical joint.

12. The gas leak rate testing device of claim 3, wherein, 15. The gas leakage rate testing device of claim 1, wherein the pipeline to be tested comprises a non-metal pipeline and a connecting joint connected to the non-metal pipeline, and the connecting joint is any one of a hot melt joint, an electric melt joint, and a mechanical joint.

13. The gas leak rate testing device of claim 1, wherein, 16. The gas leakage rate testing device of claim 1, wherein the gas comprises at least one of hydrogen, helium, natural gas, nitrogen, methane, gas, and carbon dioxide.

14. The gas leak rate testing device of claim 2, wherein, 17. The method of claim 1, wherein the method comprises:

15. The gas leak rate testing device of claim 3, wherein, after placing the pipeline to be tested in the detection cavity to form a sealed test cavity, performing vacuumizing on the test cavity; 16. The gas leak rate testing device of claim 1, wherein, discharging air in the pipeline to be tested, and injecting a gas at a second set pressure into the pipeline to be tested; 17. A method for testing the gas leakage rate of a non-metallic hydrogen transport pipeline, characterized in that, after gas leakage in the pipeline to be tested reaches equilibrium, acquiring a pressure change value of the test cavity within a preset time interval, and calculating a gas leakage rate of the pipeline to be tested based on the preset time interval, the pressure change value, and a calculated volume of the test cavity and a current temperature in the test cavity. ​ ​ ​ 18. A method of testing a gas permeation rate of a non-metallic hydrogen transport pipe, characterized by, The method comprises: After placing the pipeline to be tested in the detection cavity, a sealed test cavity is formed, and then the test cavity is vacuumized; Air in the pipeline to be tested is discharged, and the pipeline to be tested is injected with a second set pressure gas; 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 calculated volume of the test cavity, and the current temperature in the test cavity.

19. A method for testing the volume expansion of a non-metallic hydrogen transport pipe, characterized by, The device comprises: A detection member is formed with a detection cavity suitable for placing a pipeline to be tested, wherein the detection cavity is formed with a sealed test cavity after the pipeline to be tested is placed in the detection cavity; A calibration cavity is in selective communication with the test cavity; A first gas injection assembly is in selective communication with the calibration cavity, suitable for injecting a first set pressure gas into the calibration cavity; A second gas injection assembly is in selective communication with the pipeline to be tested, suitable for injecting a second set pressure gas into the pipeline to be tested; A measurement unit is configured to measure the pressure and temperature in the calibration cavity and the pressure and temperature in the test cavity, and to calculate the calculated volume of the test cavity based on the first pressure and the first temperature in the calibration cavity before the calibration cavity is in communication with the test cavity, the second pressure and the second temperature in the test cavity, and the third pressure and the third temperature in the test cavity after the calibration cavity is in communication with the test cavity and the pipeline to be tested reaches leakage equilibrium; A leakage rate test unit is configured to obtain the pressure change value of the test cavity within a preset time interval, and to 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 cavity, and the calculated volume of the test cavity after the pipeline to be tested reaches leakage equilibrium. The non-metallic hydrogen pipeline volume expansion testing method comprises: Before the gas permeation rate test is performed, the measuring unit calculates the first volume of the test chamber based on the following second formula: Wherein, V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, 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 gas leakage rate of the non-metallic hydrogen pipeline is tested according to the gas leakage rate testing method of the non-metallic hydrogen pipeline of claim 17. After the gas leakage rate test is completed, the measurement unit calculates a second volume of the test cavity 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.

20. A method of testing the volume expansion of a non-metallic hydrogen transport pipe, characterized by, The device comprises: a detection piece, which is formed with a detection cavity suitable for placing a 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, which is in selective communication with the test cavity; a first gas injection assembly, which is in selective communication with the calibration cavity, and is suitable for injecting a gas at a first set pressure into the calibration cavity; a second gas injection assembly, which is in selective communication with the pipeline to be tested, and is suitable for injecting a gas at a second set pressure into the pipeline to be tested; a measurement unit, which is configured to measure the pressure and temperature in the calibration cavity and the pressure and temperature in the test cavity, and to calculate the calculated volume of the test cavity based on the first pressure and the first temperature in the calibration cavity before the calibration cavity is in communication with the test cavity, the second pressure and the second temperature in the test cavity, and the third pressure and the third temperature in the test cavity after the pipeline to be tested is balanced for leakage; a leakage rate test unit, which is configured to obtain the pressure change value of the test cavity within a preset time interval, and to 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 cavity, and the calculated volume of the test cavity after the pipeline to be tested is balanced for leakage; The leakage rate test unit calculates the gas leakage rate of the pipeline to be tested based on the following first formula: wherein J represents the gas leakage rate, ΔP is the pressure change value, Δt is the preset time interval, V2 is the calculated volume of the test cavity, R is the molar gas constant, T is the current temperature in the test cavity, and L is the length of the pipeline to be tested; The non-metallic hydrogen pipeline volume expansion amount test method comprises: Before the gas permeation rate test is performed, the measuring unit calculates the first volume of the test chamber based on the following second formula: wherein V1 represents the calculated volume of the calibration cavity, V2 represents the calculated volume of the test cavity, 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 gas leakage rate test of the non-metallic hydrogen pipeline is performed as described in claim 18; After the gas leakage rate test is completed, the measurement unit calculates a second volume of the test cavity based on the second formula, and calculates the volume expansion amount of the pipeline to be tested based on the difference between the first volume and the second volume.

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