Pressure system airtight leak detection device and method

Abstract

The invention relates to an airtight leak detection device and method for a pressure system. The device solves the problems in the prior art that the judgment standards are not unified, quantitative measurement cannot be achieved, the airtight leak detection results of the entire pipeline system are unstable, and detection automation cannot be achieved. The leak detection system comprises a pressure storage buffer bottle, a differential pressure gauge, a self-test pressure storage bottle, a self-test pipeline, a main pipeline, an exhaust pipeline, a balancing valve, a first stop valve, a boosting component, and two groups of temperature sensors. One end of the main pipeline is connected to the pressure storage buffer bottle, and the other end is used to connect to the pipeline system to be tested, and the first stop valve is installed at the other end of the main pipeline. The exhaust pipeline, the self-test pipeline and the differential pressure gauge are all arranged on the main pipeline, and the other end of the exhaust pipeline is connected to an external device. The other end of the self-test pipeline is connected to the self-test pressure storage bottle. The balancing valve is arranged on the main pipeline between the two ends of the differential pressure gauge. Two groups of temperature sensors are installed on the main pipeline. The invention also proposes an airtight leak detection method for the leak detection device.

Description

Technical Field

[0001] The invention relates to airtight leak detection equipment and method, and in particular to airtight leak detection equipment and method for a pressure system. Background Art

[0002] Most of the existing airtight leak detection methods use the soap bubble leak detection method, which is specifically: pre-pressurize the entire pipeline system, close the pressurization control valve after pressurization, and then apply soapy water to the joints, welding connections and other parts of the entire pipeline system that are prone to leakage, and observe the number and frequency of soap bubbles generated in the above parts. If the soap bubbles generated in a certain part are large and the frequency is high, it can be preliminarily determined that the leakage in this part is more serious. If the soap bubbles generated in a certain part are small and the frequency is low, it can be preliminarily determined that there is a slight leak in this part. Then, a stopwatch is used to time the part where the bubbles are generated, and the number of bubbles is visually observed to qualitatively determine whether it meets the leakage requirements. If it does not meet the requirements, it is processed and leak detection is performed again until it meets the requirements.

[0003] However, when using the soap bubble leak detection method for airtight leak detection, there is an inconsistency in the judgment standards. When the system is different or the concentration of soap water is different, the results obtained are also different. Quantitative measurement cannot be achieved, and qualitative judgment can only be made through empirical data. This will ultimately lead to unstable airtight leak detection results for the entire pipeline system and the inability to achieve automated detection. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the prior art that the judgment standards are not unified, quantitative measurement cannot be achieved, the airtight leak detection results of the entire pipeline system are unstable, and detection automation cannot be achieved, and a pressure system airtight leak detection device and method are provided.

[0005] The technical solution adopted by the present invention is:

[0006] A pressure system airtight leak detection device, which is special in that:

[0007] It includes a pressure storage buffer bottle, a differential pressure gauge, a self-test pressure storage bottle, a self-test pipeline, a main pipeline, an exhaust pipeline, a balancing valve, a first stop valve, two sets of temperature sensors and a booster assembly;

[0008] One end of the main pipeline is connected to the pressure storage buffer bottle, and the other end is used to communicate with the pipeline system to be inspected. The first stop valve is installed at the other end of the main pipeline connected to the pipeline system to be inspected, and is used to control the connection and disconnection between the two.

[0009] One end of the exhaust pipeline, one end of the self-test pipeline and the differential pressure gauge are all arranged on the main pipeline, and the exhaust pipeline and the self-test pipeline are located between the differential pressure gauge and the first stop valve, and the other end of the exhaust pipeline is connected to the external device; the other end of the self-test pipeline is connected to the self-test pressure storage bottle;

[0010] The balancing valve is arranged on the main pipe between the two ends of the differential pressure gauge;

[0011] Two groups of temperature sensors are installed on the main pipeline, wherein one group is located between the first stop valve and the pipeline system to be inspected, and is used to monitor the temperature of the pipe wall at one end of the main pipeline connected to the pipeline system to be inspected and the gas in the pipe, and the other group is located between the pressure storage buffer bottle and the differential pressure gauge, and is used to monitor the temperature of the pipe wall at one end of the main pipeline connected to the pressure storage buffer bottle and the gas in the pipe, and each group of temperature sensors includes at least two temperature sensors, wherein at least one temperature sensor is used to monitor the temperature of the gas in the pipe, and at least one temperature sensor is used to monitor the temperature of the pipe wall;

[0012] The boosting assembly is communicated with the main pipeline and is located between the first stop valve and the differential pressure gauge.

[0013] Furthermore, the boosting assembly includes a boosting pipeline and a boosting pump;

[0014] One end of the boosting pipeline is connected to the main pipeline, and the other end is connected to the boosting pump. The boosting pipeline is arranged between the differential pressure gauge and the first stop valve.

[0015] Furthermore, it also includes a pressure gauge arranged on the main pipe;

[0016] The pressure gauge is located between the differential pressure gauge and the pressure storage buffer bottle, and is used to measure the pressure on the main pipe between the differential pressure gauge and the pressure storage buffer bottle in real time.

[0017] Furthermore, a second stop valve is provided on the self-test pipeline;

[0018] A pressure relief valve is provided on the exhaust pipe;

[0019] The boost pipeline is provided with a third stop valve.

[0020] The present invention also provides a pressure system airtight leak detection method, which is special in that it is based on the above-mentioned pressure system airtight leak detection device and includes the following steps:

[0021] Step 1: Self-check

[0022] 1.1 Open the self-test pipeline and the balancing valve, increase the pressure in the main pipeline, and stop increasing the pressure in the main pipeline after the gas and the wall temperature in the main pipeline are stable, and close the balancing valve, and observe and record the pressure change value of the differential pressure gauge within the preset time;

[0023] 1.2 If the pressure change value of the differential pressure gauge is within the specified range, it means that the airtightness of the pressure system airtight leak detection equipment is good. Open the exhaust pipeline to release the pressure. After the pressure is released, close the exhaust pipeline and the self-test pipeline, and proceed to step 2. If not, it means that there is a leak in the pressure system airtight leak detection equipment. Open the exhaust pipeline to release the pressure. After repairing the pressure system airtight leak detection equipment, close all pipelines and return to step 1.1.

[0024] Step 2: Inspection of the pipeline system to be inspected

[0025] 2.1 Open the first stop valve and the balancing valve to increase the pressure in the main pipeline until the pressure in the main pipeline is the same as the rated pressure in the pipeline system under inspection;

[0026] 2.2 After the temperature of the gas and the pipe wall at both ends of the main pipeline is stable, close the balancing valve, observe and record the pressure change value of the differential pressure gauge within the preset time, and determine the leakage of the pipeline system under inspection;

[0027] 2.3 If the pressure change value of the differential pressure gauge is within the specified range, it means that the air tightness of the pipeline system under test is good. Open the exhaust pipeline to release the pressure. After the pressure is released, close the exhaust pipeline and disconnect the main pipeline from the pipeline system under test to complete the air tightness leak detection of the pressure system.

[0028] If not, it means that there is a leak in the pipeline system being tested. Open the exhaust pipeline to release the pressure. After the pressure is released, close the exhaust pipeline and perform step 2.4.

[0029] 2.4 Starting from the end where the pipeline system under test is connected to the main pipeline, close the valves in the pipeline system under test one at a time in sequence along the reverse flow direction of the gas, that is, close the valves in the pipeline system under test one at a time in sequence from the end connected to the main pipeline to the end away from the main pipeline, and use the same operation method as steps 2.2-2.3 to perform segmented inspection on the pipeline system under test in turn until the specific part with leakage in the pipeline system under test is found, open the exhaust pipeline to relieve the pressure, and after repairing the specific part with leakage in the pipeline system under test, return to step 2.1 until the pipeline system under test is found to be leak-free, and the pressure system airtight leak detection is completed.

[0030] Furthermore, in step 1.1, the method of increasing the pressure in the main pipeline is:

[0031] Open the booster assembly to increase the pressure in the main pipeline through the booster assembly, or when there is a gas source in the pipeline system under inspection, open the first stop valve, and the gas in the pipeline system under inspection enters the main pipeline to increase the pressure of the main pipeline.

[0032] Furthermore, in step 1.1, observing and recording the pressure change value of the differential pressure gauge within the preset time is to observe and record the pressure change value of the differential pressure gauge from the 5th minute to the 15th minute after closing the balancing valve.

[0033] Furthermore, in step 2.2, the pressure change value of the differential pressure gauge within the preset time is observed and recorded, and the pressure change value of the differential pressure gauge from the 5th minute to the 15th minute after closing the balancing valve is observed and recorded. The measurement result obtained by using the pressure change value of the differential pressure gauge from the 5th minute to the 15th minute after closing the balancing valve can accurately reproduce the measurement result under steady state.

[0034] Furthermore, in step 2.1, the specific method of pressurizing the main pipeline is:

[0035] When the pipeline system under test has a gas source, the gas in the pipeline system under test enters the main pipeline for pressurization and is stored in the pressure storage buffer bottle. After pressurization, if the pressure in the main pipeline is the same as the rated pressure in the pipeline system under test, proceed to step 2.2. If it is less than the rated pressure in the pipeline system under test, the main pipeline is pressurized by external pressurization until the pressure in the main pipeline is the same as the rated pressure in the pipeline system under test.

[0036] When there is no gas source in the pipeline system under inspection: use external pressurization to pressurize the main pipeline until the pressure in the main pipeline is the same as the rated pressure in the pipeline system under inspection.

[0037] Furthermore, the prescribed range is less than 2Pa.

[0038] The beneficial effects of the present invention are:

[0039] 1. The present invention proposes a pressure system airtight leak detection device, which is a set pressure system airtight leak detection device. Combined with the existing soap bubble leak detection technology, on the basis of a large number of tests, it can be tested according to the leakage rate requirements of different systems, and quantitative leak detection standards for different systems can be formulated to guide the later use of the leak detection device. The soap bubble leak detection technology can be used to first determine the leakage level of different systems, and then the leakage level can be quantified using the device proposed by the present invention to form a quantitative standard. The quantitative standard serves as a quantitative measurement standard in the leak detection of the device to guide the determination of the quantitative results of the leak detection.

[0040] 2. The pressure system airtight leak detection device proposed by the present invention realizes the automation, digitization and standardization of airtight leak detection.

[0041] 3. The present invention proposes a pressure system airtight leak detection device, which has two groups of temperature sensors that can eliminate the pressure changes introduced by the changes in the pipe wall temperature and the temperature of the gas in the pipe, reduce or eliminate the measurement error or measurement result uncertainty introduced into the final measurement result by these two temperature changes (the pressure changes caused by temperature changes in other places can be almost ignored, while the two factors of pipe wall temperature and gas temperature changes in the pipe are the key influencing factors that cause the actual measured pressure changes in the main pipeline), thereby reducing or eliminating the influence of these two factors on the differential pressure change of the entire pressure system airtight leak detection device, eliminating the change in the pressure in the cavity caused by the change in gas volume caused by the gas temperature change, and eliminating the measurement error or measurement result uncertainty introduced by the deformation of the pipe wall material under the influence of temperature change, resulting in a slight change in the volume of the internal cavity, which ultimately causes the influence of the change in the internal differential pressure, thereby reducing or eliminating the influence of these two factors on the differential pressure change of the entire pressure system airtight leak detection device.

[0042] 4. The pressure system airtight leak detection method proposed by the present invention eliminates the interference of the pressure system airtight leak detection equipment's own leakage by performing a self-test first, so that the detection result of the pipeline system under test is accurate and reliable.

[0043] 5. The present invention proposes a method for detecting airtightness of a pressure system, which uses the pressure change value of the differential pressure gauge from the 5th minute to the 15th minute after closing the balancing valve, and the measurement result obtained can accurately reproduce the measurement result under steady state.

[0044] 6. The present invention proposes a pressure system airtight leak detection method. When detecting the tested pipeline, the pressure in the main pipeline is increased to the rated pressure in the tested pipeline system. The obtained measurement result can further reproduce the shape under the working state to ensure the reliability of the measurement result. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the structural principle of an embodiment of the present invention;

[0046] In the figure, 1. self-test pressure storage bottle; 2. exhaust pipeline; 3. pressure storage buffer bottle; 4. pressure gauge; 5. differential pressure gauge; 6. booster pump; 7. booster pipeline; 8. main pipeline; 9. balancing valve; 10. self-test pipeline; 11. first stop valve; 12. second stop valve; 13. third stop valve; 14. pressure relief valve; 15. temperature sensor. DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] The present invention provides a pressure system airtight leak detection device, such as Figure 1As shown, it includes a self-test pressure storage bottle 1, an exhaust pipeline 2, a pressure storage buffer bottle 3, a pressure gauge 4, a differential pressure gauge 5, a booster pump 6, a booster pipeline 7, a main pipeline 8, a balance valve 9, a self-test pipeline 10, a first stop valve 11, a second stop valve 12, a third stop valve 13, a pressure relief valve 14 and two sets of sensors 15;

[0049] One end of the main line 8 is used to connect with the pipeline system under inspection, and the other end is connected to the pressure storage buffer bottle 3. The first stop valve 11 is installed at the end where the main line 8 connects with the pipeline system under inspection, and is used to control the on-off of the pipeline system under inspection and the main line 8. Both ends of the differential pressure gauge 5 are connected to the main line 8, and the balancing valve 9 is installed on the main line 8 between the two ends of the differential pressure gauge 5.

[0050] Each group of temperature sensors 15 includes an insertion temperature sensor inserted into the main pipeline 8 for measuring the real-time temperature of the gas in the main pipeline 8 and a surface-mounted temperature sensor installed on the outer pipe wall of the main pipeline 8 for measuring the real-time temperature of the pipe wall of the main pipeline 8; the two groups of temperature sensors 15 are respectively used to connect the pipe wall and the actual temperature of the gas in the pipe at both ends of the main pipeline 8 of the pipeline system to be inspected and the pressure storage buffer bottle 3. The function of the insertion temperature sensor is to eliminate the deformation of the pipeline due to the temperature introduction of the pipeline wall material, thereby causing a slight change in the volume of the internal cavity, and finally causing the influence of the internal differential pressure change; the surface-mounted temperature sensor is used to eliminate the pressure change introduced by the temperature change, thereby causing the influence of the differential pressure change of the entire pressure system airtight leak detection equipment.

[0051] In order to monitor in real time the pressure on the main line 8 during pressurization and the pressure on the main line 8 between the differential pressure gauge 5 and the pressure storage buffer bottle 3 after closing the balancing valve 9, a pressure gauge 4 is installed on this section of the main line 8.

[0052] In order to realize multiple inspections of the pipeline system under inspection without dismantling the connection between the main pipeline 8 and the pipeline system under inspection, an exhaust pipeline 2 is arranged between the differential pressure gauge 5 and the first stop valve 11, and a pressure relief valve 14 is arranged on the exhaust pipeline 2. One end of the exhaust pipeline 2 is connected to the main pipeline 8, and the other end is connected to an external device, and the external device is used to receive the gas discharged from the exhaust pipeline 2.

[0053] In order to realize the self-inspection of the pressure system airtight leak detection equipment and eliminate the influence of the pressure system airtight leak detection equipment's own factors on the airtightness of the inspected pipeline system, a self-inspection pipeline 10 is set between the differential pressure gauge 5 and the first stop valve 11. One end of the self-inspection pipeline 10 is connected to the main pipeline 8, and the other end is connected to the self-inspection pressure storage bottle 1. The second stop valve 12 is installed on the self-inspection pipeline 10.

[0054] In order to ensure that the pressure in the main line 8 is the same as the rated pressure in the inspected pipeline system and to realize the self-inspection function, a boosting pipeline 7 is set. One end of the boosting pipeline 7 is connected to the main line 8, and the other end is connected to the boosting pump 6. The third stop valve 13 is installed on the boosting pipeline 7. When the pressure in the main line 8 does not reach the rated pressure in the inspected pipeline system, the boosting pump 6 is used for pressurization.

[0055] The detection method based on the above device includes the following steps:

[0056] Before use, all valves in the equipment are closed and the pipeline to be inspected is connected;

[0057] Step 1: Self-check

[0058] 1.1 Open the second stop valve 12 and the balancing valve 9. When there is a gas source in the pipeline system to be inspected, you can choose to open the first stop valve 11 or the third stop valve 13 and the booster pump 6. When there is no gas source, open the third stop valve 13 and the booster pump 6, and increase the pressure in the main pipeline 8 through the pipeline system to be inspected or the booster pump 6. After the gas and pipe wall temperatures in the pipe measured by the two groups of temperature sensors 15 or the group of temperature sensors 15 at one end of the main pipeline 8 connected to the pressure storage buffer bottle 3 are stable, close the first stop valve 11 or the third stop valve 13, close the balancing valve 9, and observe and record the pressure change value of the differential pressure gauge 5 from the 5th minute to the 15th minute after the balancing valve 9 is closed;

[0059] 1.2 If the pressure change value of the differential pressure gauge 5 is less than 2Pa, it means that the airtightness of the pressure system airtight leak detection equipment is good. Open the pressure relief valve 14 to release the pressure on the main line 8. After the pressure is released, close the pressure relief valve 14 and the second stop valve 12 and proceed to step 2. Otherwise, it means that there is a leak in the pressure system airtight leak detection equipment. Open the pressure relief valve 14 to release the pressure on the main line 8. After the pressure system airtight leak detection equipment is repaired, return to step 1.1.

[0060] Step 2: Inspection of the pipeline system to be inspected

[0061] 2.1 Open the first stop valve 11 and the balancing valve 9. If there is a gas source in the pipeline system to be inspected, the gas in the pipeline system to be inspected enters the main pipeline 8 for pressurization and is stored in the pressure storage buffer bottle 3. When the reading of the pressure gauge 4 is stable, compare the reading of the pressure gauge 4 with the rated pressure in the pipeline system to be inspected. If they are the same, proceed to step 2.2. If it is less than the rated pressure in the pipeline system to be inspected, open the third stop valve 13 and the booster pump 6 to pressurize the main pipeline 8 until the reading of the pressure gauge 4 is equal to the rated pressure in the pipeline system to be inspected. Then proceed to step 2.2. There will be no situation where the pressure is greater than the rated pressure in the pipeline system to be inspected.

[0062] If the pipeline system to be inspected has no air source, continue to open the third stop valve 13 and the booster pump 6, pressurize the pipeline system to be inspected and the main pipeline 8, observe the reading of the pressure gauge 4, and after the pressure is increased to the rated pressure of the airtight leak detection, close the booster pump 6 and the third stop valve 13 on the booster pipeline;

[0063] 2.2 After the pressurization is completed, wait until the temperature of the gas in the pipe and the pipe wall at both ends of the main pipe 8 is stable, close the balancing valve 9, observe and record the pressure change value of the differential pressure gauge 5 from the 5th minute to the 15th minute after the balancing valve 9 is closed, and judge the leakage of the pipeline system under inspection;

[0064] 2.3 If the pressure change value of the differential pressure gauge 5 is less than 2Pa, it means that the air tightness of the pipeline system under test is good. Open the exhaust pipeline 2 to release the pressure. After the pressure is released, close the exhaust pipeline 2 and disconnect the main pipeline 8 from the pipeline system under test to complete the pressure system airtight leak detection. 2Pa can be adjusted according to actual needs;

[0065] If not, it means that there is a leak in the pipeline system under inspection. Open the exhaust pipeline 2 to release the pressure. After the pressure is released, close the exhaust pipeline 2 and execute step 2.2.

[0066] 2.4 Starting from the end where the pipeline system under test is connected to the main pipeline 8, close the valves in the pipeline system under test one at a time in sequence along the reverse flow direction of the gas, and use the same operation method as steps 2.2-step 2.3 to perform segmented inspection on the pipeline system under test in turn until the specific location of the leak in the pipeline system under test is found, open the exhaust pipeline 2 to relieve the pressure, and after repairing the specific location of the leak in the pipeline system under test, return to step 2.1 until the pipeline system under test is found to be leak-free, and the pressure system airtight leak detection is completed.

[0067] The differential pressure gauge 5 can be a micro differential pressure gauge (micro differential pressure transmitter or micro differential pressure digital pressure gauge, etc.), and the range of the differential pressure gauge 5 is selected according to the actual test situation, which can be 1kPa, 2.5kPa or 10kPa; the accuracy level is selected to be 0.05 or other levels that meet the measurement requirements, and the pressure resistance of the differential pressure gauge 5 must meet the highest pressure during the airtight inspection;

[0068] The pressure gauge 4 can be a pressure transmitter or a digital pressure gauge, etc. The range of the pressure gauge 4 is selected according to the actual leak detection pressure, or the range is selected according to the actual stamping pressure, and the range can be selected according to 6MPa, 10MPa or 25MPa. The range of the pressure gauge 4 needs to match the actual stamping pressure, and the actual stamping pressure is about 60% of the full range of the pressure gauge. The accuracy level of the pressure gauge 4 is selected to be 0.05 or other levels that meet the measurement requirements;

[0069] The volume of the pressure storage buffer bottle 3 is sufficient to meet the pressure balance buffer, and is used as a standard pressure storage pressure source. 2L can be selected. The material of the pressure storage buffer bottle 3 needs to be less affected by temperature and is used as a non-leakage standard;

[0070] The boosting range of the boosting pump 6 is selected according to the actual punching pressure range;

[0071] This method is particularly suitable for pipeline systems that are only composed of pipelines, joints, and valves. When a leak is confirmed, the valves inside the pipeline system are gradually closed, and the pipeline system is tested section by section until the specific location of the leak is determined.

Claims

1. A pressure system airtight leak detection device, characterized in that: It comprises a pressure storage buffer bottle (3), a differential pressure gauge (5), a self-testing pressure storage bottle (1), a self-testing pipeline (10), a main pipeline (8), an exhaust pipeline (2), a balancing valve (9), a first stop valve (11), two sets of temperature sensors (15) and a pressurizing component; One end of the main pipeline (8) is connected to the pressure storage buffer bottle (3), and the other end is used to communicate with the pipeline system to be inspected. The first stop valve (11) is installed at the other end of the main pipeline (8) connected to the pipeline system to be inspected, and is used to control the connection and disconnection between the two. One end of the exhaust pipeline (2), one end of the self-test pipeline (10) and the differential pressure gauge (5) are all arranged on the main pipeline (8), and the exhaust pipeline (2) and the self-test pipeline (10) are located between the differential pressure gauge (5) and the first stop valve (11), and the other end of the exhaust pipeline (2) is connected to an external device; the other end of the self-test pipeline (10) is connected to the self-test pressure storage bottle (1); The balancing valve (9) is arranged on the main pipe (8) between the two ends of the differential pressure gauge (5); Two groups of temperature sensors (15) are installed on the main pipeline (8), wherein one group is located between the first stop valve (11) and the pipeline system to be inspected, and is used to monitor the temperature of the pipe wall at one end of the main pipeline (8) communicating with the pipeline system to be inspected and the temperature of the gas in the pipe, and the other group is located between the pressure storage buffer bottle (3) and the differential pressure gauge (5), and is used to monitor the temperature of the pipe wall at one end of the main pipeline (8) communicating with the pressure storage buffer bottle (3) and the temperature of the gas in the pipe, and each group of temperature sensors (15) includes at least two temperature sensors, wherein at least one temperature sensor (15) is used to monitor the temperature of the gas in the pipe, and at least one temperature sensor (15) is used to monitor the temperature of the pipe wall; The booster assembly is in communication with the main pipeline (8) and is located between the first stop valve (11) and the differential pressure gauge (5).

2. The pressure system airtight leak detection device according to claim 1, characterized in that: The boosting assembly comprises a boosting pipeline (7) and a boosting pump (6); One end of the boosting pipeline (7) is connected to the main pipeline (8), and the other end is connected to the boosting pump (6). The boosting pipeline (7) is arranged between the differential pressure gauge (5) and the first stop valve (11).

3. A pressure system airtight leak detection device according to claim 2, characterized in that: It also includes a pressure gauge (4) arranged on the main pipe (8); The pressure gauge (4) is located between the differential pressure gauge (5) and the pressure storage buffer bottle (3) and is used to measure the pressure on the main pipe (8) between the differential pressure gauge (5) and the pressure storage buffer bottle (3) in real time.

4. A pressure system airtight leak detection device according to claim 3, characterized in that: The self-test pipeline (10) is provided with a second stop valve (12); The exhaust pipeline (2) is provided with a pressure relief valve (14); The boosting pipeline (7) is provided with a third stop valve (13).

5. A pressure system airtight leak detection method, characterized in that: A pressure system airtight leak detection device according to any one of claims 1 to 4 comprises the following steps: Step 1: Self-check 1.1 Open the self-test pipeline (10) and the balancing valve (9) to increase the pressure in the main pipeline (8). After the gas in the pipeline and the temperature of the pipeline wall of the main pipeline (8) are stable, stop increasing the pressure in the main pipeline (8), close the balancing valve (9), and observe and record the pressure change value of the differential pressure gauge (5) within a preset time; 1.2 If the pressure change value of the differential pressure gauge (5) is within the specified range, it means that the airtightness of the pressure system airtight leak detection device is good. Open the exhaust pipe (2) to release the pressure. After the pressure is released, close the exhaust pipe (2) and the self-test pipe (10) and proceed to step 2. If not, it means that there is a leak in the pressure system airtight leak detection device. Open the exhaust pipe (2) to release the pressure. After repairing the pressure system airtight leak detection device, return to step 1.

1. Step 2: Inspection of the pipeline system to be inspected 2.1 Open the first stop valve (11) and the balancing valve (9) to increase the pressure in the main pipeline (8) until the pressure in the main pipeline (8) is the same as the rated pressure in the pipeline system to be inspected; 2.2 After the temperature of the gas in the pipe and the pipe wall at both ends of the main pipe (8) is stabilized, close the balancing valve (9), observe and record the pressure change value of the differential pressure gauge (5) within a preset time, and determine the leakage of the pipeline system under inspection; 2.3 If the pressure change value of the differential pressure gauge (5) is within the specified range, it means that the air tightness of the pipeline system under test is good. Open the exhaust pipeline (2) to release the pressure. After the pressure is released, close the exhaust pipeline (2) and disconnect the main pipeline (8) from the pipeline system under test to complete the air tightness leak detection of the pressure system. If not, it means that there is a leak in the pipeline system under inspection. Open the exhaust pipeline (2) to release the pressure. After the pressure is released, close the exhaust pipeline (2) and execute step 2.

4. 2.4 Starting from the end of the pipeline system under test connected to the main pipeline (8), close the valves in the pipeline system under test one at a time in sequence along the reverse flow direction of the gas, and use the same operation method as steps 2.2 to 2.3 to perform segmented inspection on the pipeline system under test in turn until the specific location of the leak in the pipeline system under test is found, open the exhaust pipeline (2) to release the pressure, and after repairing the specific location of the leak in the pipeline system under test, return to step 2.1 until the pipeline system under test is found to be leak-free, completing the pressure system airtight leak detection.

6. A pressure system airtight leak detection method according to claim 5, characterized in that: In step 1.1, the method of increasing the pressure in the main pipeline (8) is: The boosting assembly is opened to increase the pressure in the main pipeline (8) through the boosting assembly, or when there is a gas source in the pipeline system to be inspected, the first stop valve (11) is opened, and the gas in the pipeline system to be inspected enters the main pipeline (8) to increase the pressure in the main pipeline (8).

7. A pressure system airtight leak detection method according to claim 6, characterized in that: In step 1.1, the step of observing and recording the pressure change value of the differential pressure gauge (5) within a preset time period is to observe and record the pressure change value of the differential pressure gauge (5) from the 5th minute to the 15th minute after closing the balancing valve (9).

8. A pressure system airtight leak detection method according to claim 7, characterized in that: In step 2.2, the step of observing and recording the pressure change value of the differential pressure gauge (5) within a preset time is to observe and record the pressure change value of the differential pressure gauge (5) from the 5th minute to the 15th minute after closing the balancing valve (9).

9. A pressure system airtight leak detection method according to claim 8, characterized in that: In step 2.1, the specific method of increasing the pressure in the main pipeline (8) is: When the pipeline system under inspection has a gas source, the gas in the pipeline system under inspection enters the main pipeline (8) for pressurization and is stored in the pressure storage buffer bottle (3). After pressurization, if the pressure in the main pipeline (8) is the same as the rated pressure in the pipeline system under inspection, step 2.2 is performed. If it is less than the rated pressure in the pipeline system under inspection, the main pipeline (8) is pressurized by external pressurization until the pressure in the main pipeline (8) is the same as the rated pressure in the pipeline system under inspection. When the pipeline system under inspection has no gas source, the main pipeline (8) is pressurized by external pressurization until the pressure in the main pipeline (8) is the same as the rated pressure in the pipeline system under inspection.

10. A pressure system airtight leak detection method according to any one of claims 5 to 9, characterized in that: The prescribed range is less than 2Pa.

Images