Pipeline leakage diffusion test device
By setting up a leaking pipe at the bottom of the soil and controlling it with a solenoid valve in the test device, the problem of frequent digging required by existing devices was solved, more accurate pipeline leakage diffusion test data was achieved, and the actual horizontal pipeline leakage scenario was simulated.
Patent Information
- Application Number
- CN202520292641.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2035-02-24
AI Technical Summary
Existing pipeline leakage diffusion testing devices have fixed leakage points, requiring frequent excavation and replacement, which leads to unstable soil conditions, distorted test data, and an inability to accurately simulate leakage in horizontally placed pipelines.
Design a pipeline leakage diffusion test device. The leakage pipeline is set at the bottom of the soil in the test pit. The size of the leakage hole is controlled by a solenoid valve. Combined with a mixed gas sensor and a purging branch, leakage simulation and data acquisition can be realized, avoiding frequent soil excavation.
It improves the accuracy of test data, the test results better reflect the actual situation, the soil condition is stable, and the operation is simple and safe.
Smart Images
Figure CN223581690U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to pipeline leakage diffusion test technical field especially relates to a pipeline leakage diffusion test device. BACKGROUND
[0002] The pipeline transportation network construction of hydrogen is still in the primary stage at the present stage, its operation system is not perfect, and the investment cost is high. At present, the industry generally agrees that a feasible hydrogen delivery scheme is to use the existing natural gas pipeline to deliver hydrogen and natural gas mixed. However, hydrogen mixed into the natural gas pipeline will bring risks to the safe operation of the natural gas pipeline, and the main body of the natural gas pipeline is a buried pipeline. When leakage occurs, the mixed gas leaked into the soil is more concealed and more difficult to monitor. Therefore, it is necessary to carry out leakage diffusion test of hydrogen mixed natural gas pipeline, especially leakage diffusion test of buried pipeline, to obtain test data of the diffusion of mixed gas in soil after leakage, and provide data support for subsequent development of monitoring and prevention schemes and related improvements.
[0003] For this, the prior art provides a related test device, but the leakage point of the device is fixed. When the leakage point needs to be changed, the leakage pipeline needs to be dug out of the soil, and after replacing the pipeline with different specifications of the leakage point, it needs to be refilled. Frequent excavation and backfilling will make the soil state unstable, and ultimately make the test data distorted. And the device places the simulated leakage pipeline vertically, which is different from the more common horizontal pipeline leakage in actual scenarios, and the test results cannot well reflect the actual situation. UTILITY MODEL CONTENTS
[0004] The utility model aims at providing a pipeline leakage diffusion test device to improve the accuracy of test data and make the test results better reflect the actual situation.
[0005] The utility model provides a pipeline leakage diffusion test device, which comprises:
[0006] A gas supply pipeline, which comprises a main pipeline and a mixed gas supply branch and a purge branch in communication with the main pipeline, the mixed gas supply branch being used for supplying mixed gas to the main pipeline, and the purge branch being used for supplying purge gas to the main pipeline;
[0007] A test pit, which is filled with soil, and the bottom of the soil is provided with a leakage pipeline, one end of the leakage pipeline being in communication with the main pipeline, and the other end being in communication with an emptying pipeline;
[0008] An electromagnetic valve, which is connected to the wall of the leakage pipeline, and the mixed gas can enter the soil through the electromagnetic valve;
[0009] A mixed gas sensor is embedded in the soil, and is used to sense the concentration of the mixed gas in the soil.
[0010] As a preferred technical scheme of the pipeline leakage diffusion test device, the mixed gas supply branch comprises:
[0011] A first gas cylinder and a second gas cylinder,
[0012] A first gas supply pipeline and a second gas supply pipeline, the first gas cylinder is communicated with the first gas supply pipeline, the second gas cylinder is communicated with the second gas supply pipeline, and the ends of the first gas supply pipeline and the second gas supply pipeline are communicated with the main pipeline through a mixing valve;
[0013] A first pressure reducing valve and a second pressure reducing valve, the first pressure reducing valve is connected to the first gas supply pipeline, and the second pressure reducing valve is connected to the second gas supply pipeline.
[0014] As a preferred technical scheme of the pipeline leakage diffusion test device, the mixed gas supply branch further comprises a first flow controller and a second flow controller, the first flow controller is connected to the first gas supply pipeline and located downstream of the first pressure reducing valve, and the second flow controller is connected to the second gas supply pipeline and located downstream of the second pressure reducing valve.
[0015] As a preferred technical scheme of the pipeline leakage diffusion test device, the purge branch comprises a third gas cylinder, a third gas supply pipeline and a third pressure reducing valve, the third gas cylinder is communicated with the third gas supply pipeline, the end of the third gas supply pipeline is communicated with the main pipeline, and the position where the third gas supply pipeline is communicated with the main pipeline is located downstream of the mixing valve, and the third pressure reducing valve is connected to the third gas supply pipeline.
[0016] As a preferred technical scheme of the pipeline leakage diffusion test device, the third gas supply pipeline is communicated with the main pipeline through a three-way valve, and the three-way valve can selectively pass only the mixed gas or only the purge gas into the main pipeline.
[0017] As a preferred technical scheme of the pipeline leakage diffusion test device, the mixed gas sensor comprises a plurality of hydrogen sensors and a plurality of methane sensors, the plurality of hydrogen sensors are uniformly embedded in the soil, the plurality of methane sensors are uniformly embedded in the soil, the hydrogen sensor is used to sense the hydrogen concentration in the soil, and the methane sensor is used to sense the methane concentration in the soil.
[0018] As a preferred technical scheme of the pipeline leakage diffusion test device, a plurality of thermometers are further included, and the plurality of thermometers are respectively used to measure the temperature of the soil at different depths.
[0019] As a preferred technical scheme of the pipeline leakage diffusion test device, the power connection end of the electromagnetic valve is connected with the power supply through the power supply line and the explosion-proof switch.
[0020] As a preferred technical scheme of the pipeline leakage diffusion test device, the leakage pipeline is further connected with a pressure sensor, and the pressure sensor is used to measure the pressure of the mixed gas or the purge gas in the leakage pipeline.
[0021] As a preferred technical scheme of the pipeline leakage diffusion test device, the evacuation pipeline is connected with an evacuation valve, and the evacuation valve is used to open or close the evacuation pipeline.
[0022] The pipeline leakage diffusion test device has the following beneficial effects:
[0023] The pipeline leakage diffusion test device provided by the utility model is arranged at the bottom of the test pit soil, is closer to the actual scene, and can change the size of the leakage hole by adjusting the opening of the electromagnetic valve when the mixed gas enters the soil through the electromagnetic valve, so that the soil does not need to be frequently excavated and filled, the state of the soil is more stable, the accuracy of test data is improved, and the test result better reflects the actual situation. BRIEF DESCRIPTION OF DRAWINGS
[0024] Fig. 1 The pipeline leakage diffusion test device is a principle diagram of the pipeline leakage diffusion test device in the embodiment of the utility model;
[0025] Fig. 2 The pipeline leakage diffusion test device is a principle diagram of the pipeline leakage diffusion test device in the embodiment of the utility model.
[0026] In the drawings:
[0027] 1, the first gas cylinder; 2, the second gas cylinder; 3, the third gas cylinder; 4, the first pressure reducing valve; 5, the second pressure reducing valve; 6, the third pressure reducing valve; 7, the first gas supply pipeline; 8, the second gas supply pipeline; 9, the third gas supply pipeline; 10, the first flow controller; 11, the second flow controller; 12, the mixing valve; 13, the three-way valve; 14, the main pipeline; 15, the thermometer; 16, the test pit; 17, the leakage pipeline; 18, the pressure sensor; 19, the electromagnetic valve; 20, the power supply line; 21, the explosion-proof switch; 22, the hydrogen sensor; 23, the methane sensor; 24, the evacuation pipeline; 25, the evacuation valve; 26, the data transmission line; 27, the explosion-proof box; 28, the data recorder. DETAILED DESCRIPTION
[0028] The technical solutions of the present application will be described clearly and completely in connection with the drawings. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.
[0029] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and moreover, the first feature is "above", "above" and "above" of the second feature, which includes the first feature above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature is "below", "below" and "below" of the second feature, which includes the first feature below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.
[0030] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0031] The embodiments of the present application will be described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application.
[0032] As Figs. 1-2The utility model provides a pipeline leakage diffusion test device, especially the leakage diffusion test device of hydrogen mixed natural gas buried pipeline in soil. The pipeline leakage diffusion test device includes gas supply pipeline, test pit 16, solenoid valve 19 and mixed gas sensor. The gas supply pipeline includes main pipeline 14 and mixed gas supply branch and purging branch communicated with the main pipeline 14, the mixed gas supply branch is used for supplying mixed gas to the main pipeline 14, and the purging branch is used for supplying purge gas to the main pipeline 14. The test pit 16 is filled with soil, and the parameters such as porosity and water content of the soil are determined according to the test requirements, which are not limited specifically here. The bottom of the soil is provided with a leakage pipeline 17, and the leakage pipeline 17 is horizontally arranged. One end of the leakage pipeline 17 is communicated with the main pipeline 14, and the other end is communicated with the emptying pipeline 24. The solenoid valve 19 is connected to the wall of the leakage pipeline 17, and the mixed gas can enter the soil through the solenoid valve 19, thereby simulating the leakage condition of the mixed gas in the actual scene. The mixed gas sensor is buried in the soil, and the mixed gas sensor is used to sense the concentration of the mixed gas in the soil. The leakage pipeline 17 in the embodiment is arranged at the bottom of the soil in the test pit 16, which is more close to the actual scene, and when the mixed gas enters the soil through the solenoid valve 19, the size of the leakage hole can be changed by adjusting the opening of the solenoid valve 19, so that the soil does not need to be frequently excavated and filled, the state of the soil is more stable, thereby improving the accuracy of the test data, and the test results better reflect the actual situation.
[0033] Further, the mixed gas supply branch includes a first gas cylinder 1, a second gas cylinder 2, a first gas supply pipeline 7, a second gas supply pipeline 8, a first pressure reducing valve 4 and a second pressure reducing valve 5. The first gas cylinder 1 contains compressed hydrogen, and the second gas cylinder 2 contains compressed methane. The first gas cylinder 1 is communicated with the first gas supply pipeline 7, and the second gas cylinder 2 is communicated with the second gas supply pipeline 8. The ends of the first gas supply pipeline 7 and the second gas supply pipeline 8 are communicated with the main pipeline 14 through a mixing valve 12. By respectively providing the first gas cylinder 1 and the second gas cylinder 2 to supply hydrogen and methane, mixed gas with different proportions can be obtained, thereby meeting the test requirements of more conditions. The first pressure reducing valve 4 is connected to the first gas supply pipeline 7, and the second pressure reducing valve 5 is connected to the second gas supply pipeline 8. The first pressure reducing valve 4 is used to adjust the gas pressure value of hydrogen in the first gas supply pipeline 7, and the second pressure reducing valve 5 is used to adjust the gas pressure value of methane in the second gas supply pipeline 8, so that the state of the mixed gas is more stable.
[0034] To realize more accurate control of the mixture gas ratio, the mixed gas supply branch further comprises a first flow controller 10 and a second flow controller 11. The first flow controller 10 is connected to the first gas supply pipeline 7 and located downstream of the first pressure reducing valve 4, and the second flow controller 11 is connected to the second gas supply pipeline 8 and located downstream of the second pressure reducing valve 5. The first flow controller 10 and the second flow controller 11 are both selected as volume flow controllers, so as to realize accurate control of the mixture gas ratio through the cooperation of the first flow controller 10 and the second flow controller 11.
[0035] Further, the purge branch comprises a third gas cylinder 3, a third gas supply pipeline 9 and a third pressure reducing valve 6. The third gas cylinder 3 contains compressed nitrogen, the third gas cylinder 3 is in communication with the third gas supply pipeline 9, the end of the third gas supply pipeline 9 is in communication with the main pipeline 14, the communication position of the third gas supply pipeline 9 with the main pipeline 14 is located downstream of the mixing valve 12, and the third pressure reducing valve 6 is connected to the third gas supply pipeline 9. By setting the purge branch to purge the main pipeline 14, the leakage pipeline 17 and the emptying pipeline 24, the air or the mixed gas in the pipelines is emptied, and the mixed gas in the soil is accelerated to be discharged from the soil, so as to ensure a good test environment for subsequent tests.
[0036] Specifically, the third gas supply pipeline 9 is in communication with the main pipeline 14 through a three-way valve 13, and the three-way valve 13 can selectively make the mixed gas or the purge gas enter the main pipeline 14. The three-way valve 13 in the embodiment is pneumatic, and has a first conduction state and a second conduction state. Two of its three joints are connected with the main pipeline 14, and the other joint is connected with the end of the third gas supply pipeline 9. When the mixed gas is supplied, the first pressure reducing valve 4 and the second pressure reducing valve 5 are opened, and the third pressure reducing valve 6 is closed, at this time the first gas cylinder 1 and the second gas cylinder 2 supply the mixed gas into the main pipeline, and the three-way valve 13 is in the first conduction state, and the two joints connected with the main pipeline 14 are in conduction, so that only the mixed gas enters the main pipeline 14. When the purge gas is supplied, the first pressure reducing valve 4 and the second pressure reducing valve 5 are closed, and the third pressure reducing valve 6 is opened, at this time the third gas cylinder 3 supplies the purge gas into the main pipeline, and under the action of the purge gas, the three-way valve 13 switches from the first conduction state to the second conduction state, and the joint connected with the third gas supply pipeline 9 and the joint connected with the main pipeline 14 located downstream are in conduction, so that only the purge gas enters the main pipeline 14. In other embodiments, the three-way valve 13 can also be set to be electric, and the same effect can also be achieved through electric control, which will not be described here.
[0037] Further, the mixed gas sensor comprises a plurality of hydrogen sensors 22 and a plurality of methane sensors 23, the plurality of hydrogen sensors 22 are uniformly buried in the soil, the plurality of methane sensors 23 are uniformly buried in the soil, the positions of the hydrogen sensors 22 and the methane sensors 23 buried in the soil are determined according to the test requirements, which will not be described here. In order to reduce the amount of work in the arrangement process, the hydrogen sensors 22 and the methane sensors 23 can be combined and buried in the soil. The hydrogen sensors 22 are used to sense the hydrogen concentration in the soil, and the methane sensors 23 are used to sense the methane concentration in the soil, so as to finally obtain the diffusion data of the mixed gas after leakage in the soil.
[0038] In addition, the mixed gas sensor further comprises a plurality of thermometers 15, and each of the plurality of thermometers 15 is used to measure the temperature of the soil at different depths. The three thermometers 15 in the embodiment are preferably arranged, and the three thermometers 15 respectively sense the temperatures of the bottom layer, the middle layer and the surface layer of the soil, so as to further enrich the diffusion data of the mixed gas after leakage in the soil. The thermometer 15 in the embodiment is selected as a probe type, and the temperatures of the soil at different depths are measured by inserting the probe into the soil at different depths. In other embodiments, the thermometer 15 can also be replaced by a temperature sensor, which can also measure the temperature of the soil.
[0039] It should be noted that the structure, working principle and use method of the hydrogen sensor 22, the methane sensor 23 and the thermometer 15 in the embodiment are all prior art in the field, and therefore will not be described here.
[0040] Specifically, referring to Fig. 2 As shown in FIG. 8, the power connection end of the electromagnetic valve 19 is connected with the power supply through the power supply line 20 and the explosion-proof switch 21. In the working environment of the pipeline leakage diffusion test device in the embodiment, there are hydrogen and methane, so the explosion-proof switch 21 is arranged to avoid danger and improve the safety of the device. When adjusting the opening degree of the electromagnetic valve 19, the voltage or current of the power supply can be changed, and the specific implementation manner is the prior art in the field, which will not be described here.
[0041] Further, the leakage pipeline 17 is also connected with a pressure sensor 18, and the pressure sensor 18 is used to measure the pressure of the mixed gas or the purge gas in the leakage pipeline 17. By arranging the pressure sensor 18, it is further ensured that the pressure of the mixed gas or the purge gas in the test process meets the requirements, so that the test result is more accurate or the purge of the main pipeline 14, the leakage pipeline 17 and the evacuation pipeline 24 by the purge gas is more thorough. Correspondingly, the evacuation pipeline 24 is connected with an evacuation valve 25, and the evacuation valve 25 can be selected as a ball valve, a stop valve or an electric control valve. By arranging the evacuation valve 25, the rapid pressure rise of the leakage pipeline 17 is facilitated.
[0042] In addition, the pipeline leakage diffusion test device further comprises a data recorder 28, the first flow controller 10, the second flow controller 11, the hydrogen sensor 22, the methane sensor 23 and the pressure sensor 18 in the embodiment are all in communication connection with the data recorder 28 through a data transmission line 26, and the data recorder 28 is used for recording relevant data from the first flow controller 10, the second flow controller 11, the hydrogen sensor 22, the methane sensor 23 and the pressure sensor 18. Meanwhile, the pipeline leakage diffusion test device is further provided with an explosion-proof box 27 to improve the safety of device operation. The data acquisition instrument is an existing device in the field, and the method of data acquisition and the method of data processing and the like are prior art in the field, which will not be described here.
[0043] When the mixed gas leakage diffusion test is performed using the pipeline leakage diffusion test device in the embodiment, first, the mixed gas supply branch, the purge branch, the main pipeline 14, the leakage pipeline 17, and the evacuation pipeline 24 are connected, and the leakage pipeline 17 is placed at the bottom of the test pit 16; the test pit 16 is filled with soil, and at the same time, the mixed gas sensor is buried in the soil, and after being connected to the data acquisition instrument, the air tightness is checked. First, the first pressure reducing valve 4, the second pressure reducing valve 5, the explosion-proof switch 21, and the evacuation valve 25 are closed, the third pressure reducing valve 6 is opened, and the opening degree of the third pressure reducing valve 6 is adjusted to make the pressure in the leakage pipeline 17 reach a certain value, then the third pressure reducing valve 6 is closed, and after a period of time, it is observed whether the pressure in the leakage pipeline 17 decreases. If the pressure in the leakage pipeline 17 does not decrease, it indicates that the air tightness is good, and the subsequent test can continue. The third pressure reducing valve 6 is continuously opened, and the evacuation valve 25 is opened, and after a period of time, it can be considered that the main pipeline 14, the leakage pipeline 17, and the evacuation pipeline 24 are filled with nitrogen. At this time, the evacuation valve 25 is closed, the third pressure reducing valve 6 is closed, the first pressure reducing valve 4 and the second pressure reducing valve 5 are opened, the first flow controller 10 and the second flow controller 11 are adjusted, and after a certain pressure is generated in the leakage pipeline 17, the evacuation valve 25 is opened. After a period of time, it can be considered that the main pipeline 14, the leakage pipeline 17, and the evacuation pipeline 24 are filled with mixed gas with a specific mixing ratio. At this time, the evacuation valve 25 is closed, the pressure in the leakage pipeline 17 is rapidly increased, and the pressure in the leakage pipeline 17 meets the requirements of the test. The explosion-proof switch 21 is opened, the mixed gas enters the soil from the electromagnetic valve 19 and diffuses, and the data of each hydrogen sensor 22 and methane sensor 23 is continuously recorded until the data does not change for a period of time. Then, the explosion-proof switch 21 is closed, and the first pressure reducing valve 4 and the second pressure reducing valve 5 are closed. At this time, no new mixed gas enters the soil, and the original mixed gas in the soil gradually escapes into the air. In this process, the data of each hydrogen sensor 22 and methane sensor 23 is continuously recorded until the data does not change for a period of time. At this time, it can be considered that there is no mixed gas escaping in the soil. Finally, the third pressure reducing valve 6 is opened again, the pressure in the leakage pipeline 17 reaches a certain value, the evacuation valve 25 is opened, and the mixed gas in the main pipeline 14, the leakage pipeline 17, and the evacuation pipeline 24 is discharged by nitrogen. After a period of time, the evacuation valve 25 is closed, the nitrogen enters the soil through the electromagnetic valve 19, the residual mixed gas in the soil is completely discharged from the soil under the push of the nitrogen, the explosion-proof switch 21 is closed, and then the test conditions can be changed for the next test. The pipeline leakage diffusion test device in the embodiment can meet the requirements of various tests without changing the structure after being arranged, the test environment is highly consistent with the actual situation, the test results are more accurate, different test conditions can be quickly switched, the operation response is timely during the test process, and the safety of the operators can be guaranteed.
[0044] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and also impossible to exhaust all the implementation modes. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application claims.
Claims
1. A pipeline leakage diffusion test apparatus, characterized in that, include: The gas supply pipeline includes a main pipeline (14) and a mixed gas supply branch and a purging branch connected to the main pipeline (14). The mixed gas supply branch is used to supply mixed gas to the main pipeline (14), and the purging branch is used to supply purging gas to the main pipeline (14). Test pit (16), the test pit (16) is filled with soil, and a leakage pipe (17) is set at the bottom of the soil. One end of the leakage pipe (17) is connected to the main pipe (14), and the other end is connected to the drain pipe (24). A solenoid valve (19) is connected to the wall of the leakage pipe (17), through which the mixed gas can enter the soil; A mixed gas sensor, which is buried in the soil, is used to sense the concentration of the mixed gas in the soil.
2. The pipeline leakage diffusion test device according to claim 1, characterized in that, The mixed gas supply branch includes: First gas cylinder (1) and second gas cylinder (2), The first gas supply pipe (7) and the second gas supply pipe (8) are connected. The first gas cylinder (1) is connected to the first gas supply pipe (7), and the second gas cylinder (2) is connected to the second gas supply pipe (8). The ends of the first gas supply pipe (7) and the second gas supply pipe (8) are connected to the main pipe (14) through a mixing valve (12). A first pressure reducing valve (4) and a second pressure reducing valve (5), wherein the first pressure reducing valve (4) is connected to the first gas supply pipe (7) and the second pressure reducing valve (5) is connected to the second gas supply pipe (8).
3. The pipeline leakage diffusion test apparatus according to claim 2, characterized in that, The mixed gas supply branch also includes a first flow controller (10) and a second flow controller (11). The first flow controller (10) is connected to the first gas supply pipeline (7) and is located downstream of the first pressure reducing valve (4). The second flow controller (11) is connected to the second gas supply pipeline (8) and is located downstream of the second pressure reducing valve (5).
4. The pipeline leakage diffusion test device according to claim 2, characterized in that, The purging branch includes a third gas cylinder (3), a third gas supply pipe (9), and a third pressure reducing valve (6). The third gas cylinder (3) is connected to the third gas supply pipe (9), and the end of the third gas supply pipe (9) is connected to the main pipe (14). The position where the third gas supply pipe (9) connects to the main pipe (14) is downstream of the mixing valve (12). The third pressure reducing valve (6) is connected to the third gas supply pipe (9).
5. The pipeline leakage diffusion test apparatus according to claim 4, characterized in that, The third gas supply pipeline (9) is connected to the main pipeline (14) via a three-way valve (13). The three-way valve (13) can selectively allow only the mixed gas or only the purging gas to be introduced into the main pipeline (14).
6. The pipeline leakage diffusion test apparatus according to claim 1, characterized in that, The mixed gas sensor includes multiple hydrogen sensors (22) and multiple methane sensors (23). The multiple hydrogen sensors (22) are uniformly buried in the soil, and the multiple methane sensors (23) are uniformly buried in the soil. The hydrogen sensors (22) are used to sense the hydrogen concentration in the soil, and the methane sensors (23) are used to sense the methane concentration in the soil.
7. The pipeline leakage diffusion test apparatus according to claim 6, characterized in that, It also includes multiple thermometers (15), which are used to measure the temperature of the soil at different depths.
8. The pipeline leakage diffusion test apparatus according to claim 1, characterized in that, The solenoid valve (19) is connected to the power supply via a power supply line (20) and an explosion-proof switch (21).
9. The pipeline leakage diffusion test apparatus according to any one of claims 1-8, characterized in that, A pressure sensor (18) is also connected to the leak pipe (17), and the pressure sensor (18) is used to measure the pressure of the mixed gas or the purge gas in the leak pipe (17).
10. The pipeline leakage diffusion test apparatus according to claim 9, characterized in that, The drain pipe (24) is connected to a drain valve (25), which is used to open or close the drain pipe (24).