An ultrahigh negative pressure gas extraction pipeline gas sample collection device and method

Abstract

This invention relates to the field of gas extraction technology, and more particularly to a gas sample collection device and method for ultra-high negative pressure gas extraction pipelines. The device includes a piston cylinder and a piston. The piston cylinder is internally divided into a balancing gas chamber and a sampling gas chamber. The balancing gas chamber is equipped with an atmospheric vent valve and a vacuum balancing valve. When the piston moves to one end, the vacuum balancing valve opens and the atmospheric vent valve closes; when the piston moves to the other end, the vacuum balancing valve closes and the atmospheric vent valve opens. The sampling gas chamber is equipped with an exhaust check valve and a vacuum check valve. The exhaust check valve allows gas to flow out of the balancing gas chamber and prevents gas from flowing in from the outside of the balancing gas chamber. The vacuum check valve allows gas to flow in from the outside of the balancing gas chamber and prevents gas from flowing out from the inside of the balancing gas chamber. During gas sample collection, the pressure between the sampling gas chamber and the balancing gas chamber is balanced, eliminating the resistance generated by the ultra-high negative pressure in the extraction pipeline, and realizing the collection of gas samples in the ultra-high negative pressure pipeline.

Description

Technical Field

[0001] This invention relates to the field of gas extraction technology, and in particular to a gas sample collection device and method for ultra-high negative pressure gas extraction pipelines. Background Technology

[0002] Gas sampling devices are used to collect gas samples from gas extraction pipeline systems under negative pressure. These samples are then analyzed in a gas laboratory. Gas samples from the gas extraction pipeline can directly determine the efficiency of the extraction system. Effective gas sampling ensures the reliable and efficient operation of the gas extraction system, guaranteeing the effective utilization of extracted gas for power generation and providing high-value green energy to enterprises and society. Because gas extraction pipelines operate under high negative pressure, gas sampling is difficult and inefficient. Especially in the ultra-negative pressure pipelines near gas extraction pump stations, traditional gas sampling devices cannot overcome the problem of high negative pressure resistance, making it almost impossible to collect gas samples. This hinders the reuse of gas in the gas extraction pipeline and results in resource waste. Summary of the Invention

[0003] To address the technical deficiencies of existing gas sampling devices for gas extraction pipelines, this invention provides a gas sampling device for ultra-high negative pressure gas extraction pipelines, comprising a piston cylinder and a piston; a front end cap is provided at one end of the piston cylinder, and a rear end cap is provided at the other end; the piston includes a piston rod passing through a guide hole, one end of the piston rod being connected to the piston body and extending into the piston cylinder, and the other end being connected to the piston handle and extending out of the piston cylinder, the shape and size of the piston body matching the piston cylinder.

[0004] The space enclosed by the piston body, the front end cover, and the piston cylinder constitutes a sampling gas chamber. An exhaust check valve and a vacuum check valve are fixedly installed on the side wall of the sampling gas chamber. The exhaust check valve allows gas to flow from inside the sampling gas chamber to outside the balance gas chamber and prevents gas from flowing from outside the sampling gas chamber to inside the balance gas chamber. The vacuum check valve allows gas to flow from outside the sampling gas chamber to inside the sampling gas chamber and prevents gas from flowing from inside the sampling gas chamber to outside the sampling gas chamber. The space enclosed by the piston body, the rear end cover, and the piston cylinder constitutes a balance gas chamber. An atmospheric vent valve and a vacuum balance valve are fixedly installed on the side wall of the balance gas chamber. When the piston moves to one end of the front end cover, the vacuum balance valve opens and the atmospheric vent valve closes; when the piston moves to one end of the front end cover, the vacuum balance valve closes and the atmospheric vent valve opens.

[0005] The vacuum balancing valve includes a hollow valve body and a hollow nozzle. The valve body and nozzle are fixedly connected or integrally formed. The hollow parts of the valve body and the hollow parts of the nozzle are arranged perpendicularly to each other to form a "+" shape. The upper part of the nozzle extends out of the piston cylinder through the side wall of the piston cylinder, and the lower part of the nozzle passes through the valve body. The hollow part inside the valve body is provided with a sliding valve core with a length greater than the length of the valve body. The sliding valve core can slide along the axial direction of the piston cylinder inside the valve body. The middle part of the sliding valve core is also provided with a connecting hole. The size of the connecting hole matches the inner diameter of the nozzle. When the sliding valve core slides to the side near the front end cover, the position of the connecting hole corresponds exactly to the position of the nozzle, and the vacuum balancing valve is open. When the sliding valve core slides to the side near the rear end cover, the position of the connecting hole and the position of the nozzle are offset, and the vacuum balancing valve is closed. The air vent valve structure is symmetrically arranged with the vacuum balancing valve structure. When the sliding valve core slides to the side near the front end cover, the position of the connecting hole and the position of the nozzle are offset, and the vacuum balancing valve is closed. When the sliding valve core slides to the side near the rear end cover, the position of the connecting hole corresponds exactly to the position of the nozzle, and the vacuum balancing valve is open.

[0006] When the sliding valve core slides to the side near the front cover, the end of the sliding valve core near the front cover extends out of the valve body, and the end near the rear cover is just flush with the valve body; when the sliding valve core slides to the side near the rear cover, the end of the sliding valve core near the rear cover extends out of the valve body, and the end near the front cover is just flush with the valve body.

[0007] A push plate is fixedly connected to the middle of the piston rod. The push plate is arranged in the balance air chamber. When the piston body moves to one end of the front cover, the push plate pushes the two sliding valve cores to slide towards the front cover, opening the vacuum balance valve and closing the atmospheric vent valve. When the push plate moves to one end of the front cover, the piston body pushes the two sliding valve cores to slide towards the rear cover, closing the vacuum balance valve and opening the atmospheric vent valve. The push plate is also provided with several through holes to ensure air pressure balance on both sides of the push plate.

[0008] The size of the pusher plate matches the inner diameter of the piston cylinder, providing support and guidance for the piston rod.

[0009] A piston ring is provided along the circumference of the piston body to ensure a good seal between the piston body and the piston cylinder.

[0010] Limiting blocks are also provided at both ends inside the valve body to limit the stroke of the sliding valve core.

[0011] The front end cover is a cylindrical structure that is closed at one end and open at the other end. The inner diameter of the front end cover matches the outer diameter of the piston cylinder. The open end of the front end cover is threaded to one end of the piston cylinder or integrally formed. The inner diameter of the rear end cover matches the outer diameter of the piston cylinder 1. The open end of the rear end cover is threaded to the other end of the piston cylinder or integrally formed.

[0012] The rear end cover has a guide hole centered along the axial direction. The size of the guide hole matches the size of the piston rod, and a graphite sleeve is embedded in the guide hole.

[0013] This invention also provides a method for collecting ultra-high negative pressure gas samples, implemented using the device of this invention, comprising the following steps:

[0014] Step 1: Install a balancing interface and a sampling interface in the gas extraction pipeline. The balancing interface is equipped with a balancing ball valve and connected to the balancing pipe. The sampling interface is equipped with a sampling ball valve and connected to the sampling pipe. The balancing ball valve and the sampling ball valve are kept closed.

[0015] Step 2: Connect the vacuum balancing valve to the balancing interface through the balancing pipe; connect the vacuum one-way valve to the negative pressure sampling interface through the negative pressure sampling pipe; connect the exhaust one-way valve to the gas sampling bag through the gas sample output pipe;

[0016] Step 3: Push the piston handle to move the piston body to the front cover. At this time, the pusher plate will push the sliding valve core to one side of the front cover, opening the vacuum balance valve and closing the atmospheric vent valve.

[0017] Step 4: Open the balance ball valve and the sampling ball valve. At this time, the balance gas chamber is connected to the gas extraction pipeline. The gas pressure in the balance gas chamber is equal to the gas pressure in the extraction pipeline. The gas pressure in the balance gas chamber is less than the gas pressure in the sampling gas chamber.

[0018] Step 5: Pull the piston handle, the piston rod moves towards the rear end cover, the sampling gas chamber space increases and the gas pressure decreases, the vacuum check valve opens and the exhaust check valve closes, the sampling gas chamber is connected to the gas extraction pipeline, the vacuum balance valve remains open and the atmospheric valve remains closed before the piston body reaches the sliding valve core position, the gas pressure in the sampling gas chamber, the extraction pipeline and the balance gas chamber remains balanced, and the gas sample in the gas extraction pipeline is filled into the sampling gas chamber;

[0019] Step 6: Continue pulling the piston handle until the piston reaches the position of the sliding valve core. The piston rod pushes the sliding valve core towards the rear cover side, closing the vacuum balance valve and opening the atmospheric vent valve.

[0020] Step 7: Push the piston handle, and the piston rod moves towards the front cover. The sampling gas chamber space is compressed and the gas pressure increases. Under the action of gas pressure, the vacuum check valve closes and the exhaust check valve opens, and the sampling gas chamber is connected to the sampling bag. Before the push plate reaches the position of the sliding valve core, the vacuum balance valve remains closed and the atmospheric valve remains open, and the gas sample in the sampling gas chamber is filled into the gas sampling bag.

[0021] Step 8: Continue pushing the piston handle until the push plate reaches the position of the sliding valve core. The push plate will push the sliding valve core towards the front cover side.

[0022] Step 9: Repeat steps 5-8.

[0023] The beneficial effects of this invention are as follows: By setting a balance gas chamber and a sampling gas chamber inside the piston cylinder, the balance gas chamber is equipped with a gas vent valve and a vacuum balance valve, and the sampling gas chamber is equipped with an exhaust check valve and a vacuum check valve, so that the pressure between the sampling gas chamber and the balance gas chamber is balanced during the gas sample collection process, eliminating the resistance generated by the ultra-high negative pressure in the extraction pipeline, and realizing the collection of gas samples in the ultra-high negative pressure pipeline. Attached Figure Description

[0024] Figure 1 Schematic diagram of the piston pull-out state of the gas sample collection device in the ultra-high negative pressure gas extraction pipeline.

[0025] Figure 2 Schematic diagram of the piston-pushing state structure of the gas sample collection device in the ultra-high negative pressure gas extraction pipeline.

[0026] Figure 3 Schematic diagram of the vacuum balance valve in the closed state;

[0027] Figure 4 Schematic diagram of the vacuum balance valve in the open state;

[0028] Figure 5 Schematic diagram of the connection between the gas sample collection device and the gas extraction pipeline in the ultra-high negative pressure gas extraction pipeline.

[0029] The attached diagram shows the following labels: 1. Piston cylinder; 2. Front end cap; 3. Rear end cap; 4. Piston; 5. Piston body; 6. Piston rod; 7. Piston handle; 8. Piston ring; 9. Guide hole; 10. Push plate; 11. Through hole; 12. Balance gas chamber; 13. Sampling gas chamber; 14. Exhaust check valve; 15. Vacuum check valve; 16. Vacuum balance valve; 17. Gas vent valve; 18. Valve body; 19. Gas nozzle; 20. Sliding valve core; 21. Limiting block; 22. Connecting hole; 23. Gas extraction pipeline; 24. Balance interface; 25. Sampling interface; 26. Balance ball valve; 27. Balance pipe; 28. Sampling ball valve; 29. ​​Sampling pipe; 30. Gas sampling bag. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings and embodiments.

[0031] See Figure 1 , 2The present invention provides a gas sample collection device for an ultra-high negative pressure gas extraction pipeline 23, including a piston cylinder 1 and a piston 4; the piston cylinder 1 is a tubular structure, with a front end cap 2 at one end and a rear end cap 3 at the other end; the front end cap 2 is a cylindrical structure with one end closed and the other end open, the inner diameter of the front end cap 2 matches the outer diameter of the piston cylinder 1, and the open end of the front end cap 2 is threadedly connected to one end of the piston cylinder 1 or integrally formed. An exhaust check valve 14 and a vacuum check valve 15 are fixedly installed on the side wall of the front cover 2. The exhaust check valve 14 adopts an existing technology structure that allows gas to flow out of the piston cylinder 1 and prevents gas from flowing into the piston cylinder 1. The vacuum check valve 15 adopts an existing technology structure that allows gas to flow into the piston cylinder 1 and prevents gas from flowing out of the piston cylinder 1. The inner diameter of the rear cover 3 matches the outer diameter of the piston cylinder 1. The open end of the rear cover 3 is threaded to the other end of the piston cylinder 1 or integrally formed. A guide hole 9 is axially centered inside the rear cover 3. The size of the guide hole 9 matches the piston 4, allowing the piston 4 to pass into the piston cylinder 1 and serving as a guide and seal. An atmospheric vent valve 17 and a vacuum balance valve 16 are fixedly installed in the middle of the inner side wall of the piston cylinder 1.

[0032] See Figure 3 , 4The vacuum balance valve 16 includes a hollow valve body 18 and a hollow air nozzle 19. The valve body 18 and the air nozzle 19 are fixedly connected or integrally formed. The hollow parts of the valve body 18 and the hollow parts of the air nozzle 19 are arranged perpendicularly to each other to form a "+" shape. The upper part of the air nozzle 19 extends out of the piston cylinder 1 through the side wall of the piston cylinder 1, and the lower part of the air nozzle 19 passes through the valve body 18. The hollow part inside the valve body 18 is provided with a sliding valve core 20 whose length is greater than the length of the valve body 18. The sliding valve core 20 can be various shapes such as cuboid and cylindrical. The sliding valve core 20 can slide along the axial direction of the piston cylinder 1 inside the valve body 18. Limiting blocks 21 are also provided at both ends inside the valve body 18 to limit the stroke of the sliding valve core 20. When the sliding valve core 20 slides to the side near the front end cover 2, the end of the sliding valve core 20 near the front end cover 2 extends out of the valve body 18, and the end near the rear end cover 3 is flush with the valve body 18. When the sliding valve core 20 is slid to one side of the rear cover 3, the end of the sliding valve core 20 near the rear cover 3 extends out of the valve body 18, and the end near the front cover 2 is flush with the valve body 18. The middle of the sliding valve core 20 is also provided with a connecting hole 22, the size of which matches the inner diameter of the air nozzle 19. When the sliding valve core 20 slides to the side near the front cover 2, the position of the connecting hole 22 corresponds exactly to the position of the air nozzle 19, and the vacuum balance valve 16 is opened. When the sliding valve core 20 slides to the side near the rear cover 3, the position of the connecting hole 22 and the position of the air nozzle 19 are offset, and the vacuum balance valve 16 is closed. The structure of the air vent valve 17 is the same as that of the vacuum balance valve 16 and they are arranged symmetrically. When the sliding valve core 20 slides to the side near the front cover 2, the position of the connecting hole 22 and the position of the air nozzle 19 are offset, and the vacuum balance valve 16 is closed. When the sliding valve core 20 slides to the side near the rear cover 3, the position of the connecting hole 22 corresponds exactly to the position of the air nozzle 19, and the vacuum balance valve 16 is opened.

[0033] See Figure 1 , 2The piston 4 includes a piston rod 6 passing through a guide hole 9. One end of the piston rod 6 is connected to the piston body 5 and extends into the piston cylinder 1, while the other end is connected to the piston handle 7 and extends out of the piston cylinder 1. The piston rod 6 is sized to match the guide hole 9 to ensure a good seal between the piston rod 6 and the guide hole 9. A graphite sleeve is embedded in the guide hole 9 to ensure smooth sliding between the piston rod 6 and the guide hole 9. The piston body 5 is a cylindrical structure with dimensions matching the inner diameter of the piston cylinder 1. A piston ring 8 is provided along the circumference of the piston body 5 to ensure a good seal between the piston body 5 and the piston cylinder 1. The space enclosed by the piston body 5, the rear end cover 3, and the piston cylinder 1 constitutes a balance air chamber 12. A large air valve 17 and a vacuum balance valve 16 are provided on the side wall of the balance air chamber 12. The size of the balance air chamber 12 changes with the movement of the piston 4. When the piston 4 moves towards the front end cover 2, the space of the balance air chamber 12 increases; when the piston 4 moves towards the rear end cover 3, the space of the balance air chamber 12 decreases. The space enclosed by the cover 2, piston cylinder 1 and the piston cylinder 1 constitutes the sampling gas chamber 13. The exhaust one-way valve 14 and the vacuum one-way valve 15 are set on the side wall of the sampling gas chamber 13. The size of the sampling gas chamber 13 changes with the movement of the piston 4. When the piston 4 moves towards the front cover 2, the space of the sampling gas chamber 13 decreases. When the piston 4 moves towards the rear cover 3, the space of the sampling gas chamber 13 increases. A push plate 10 is set in the middle of the piston rod 6. The size of the push plate 10 matches the inner diameter of the piston cylinder 1 and provides support and guidance for the piston rod 6. When the piston body 5 moves to one end of the front cover 2, the push plate 10 pushes the two sliding valve cores 20 to slide towards the front cover 2, the vacuum balance valve 16 opens and the atmospheric vent valve 17 closes. When the push plate 10 moves to one end of the front cover 2, the piston body 5 pushes the two sliding valve cores 20 to slide towards the rear cover 3, the vacuum balance valve 16 closes and the atmospheric vent valve 17 opens. The push plate 10 is also provided with several through holes 11 to ensure the air pressure balance on both sides of the push plate 10.

[0034] See Figure 5 The present invention also provides a method for collecting ultra-high negative pressure gas samples, the specific steps of which are as follows:

[0035] Step 1: The gas extraction pipeline 23 is an ultra-high negative pressure pipeline. A balancing interface 24 and a sampling interface 25 are set in the gas extraction pipeline 23. The balancing interface 24 is equipped with a balancing ball valve 26 and is connected to the balancing pipe 27. The sampling interface 25 is equipped with a sampling ball valve 28 and is connected to the sampling pipe 29. The balancing ball valve 26 and the sampling ball valve 28 are kept closed. The balancing interface 24, the sampling interface 25, the balancing ball valve 26, and the sampling ball valve 28 are all existing technical structures.

[0036] Step 2: Connect the vacuum balance valve 16 of the gas sample collection device in the ultra-high negative pressure gas extraction pipeline 23 to the balance interface 24 through the balance pipe 27; connect the vacuum one-way valve 15 to the negative pressure sampling interface 25 through the negative pressure sampling pipe 29; connect the exhaust one-way valve 14 to the gas sampling bag 30 through the gas sample output pipe.

[0037] Step 3: Push the piston handle 7 to move the piston body 5 to the front cover 2. At this time, the pusher plate 10 pushes the sliding valve core 20 to one side of the front cover 2, and the vacuum balance valve 16 opens and the atmospheric valve 17 closes.

[0038] Step 4: Open the balance ball valve 26 and the sampling ball valve 28. At this time, the balance gas chamber 12 is connected to the gas extraction pipeline 23. The gas pressure in the balance gas chamber 12 is equal to the gas pressure in the extraction pipeline. The gas pressure in the balance gas chamber 12 is less than the gas pressure in the sampling gas chamber 13.

[0039] Step 5: Pull the piston handle 7. Since the air pressure in the balance gas chamber 12 is less than that in the sampling gas chamber 13 at this time, the pulling process is less strenuous. As the piston rod 6 moves towards the rear end cover 3, the space of the sampling gas chamber 13 increases and the air pressure decreases. Under the action of air pressure, the vacuum check valve 15 opens and the exhaust check valve 14 closes. The sampling gas chamber 13 is connected to the gas extraction pipeline 23. Before the piston body 5 reaches the position of the sliding valve core 20, the vacuum balance valve 16 remains open and the atmospheric valve 17 remains closed. The air pressure in the sampling gas chamber 13, the extraction pipeline, and the balance gas chamber 12 remains balanced, eliminating the pressure difference between the two ends of the piston body 5, so that the gas sample in the gas extraction pipeline 23 can be smoothly filled into the sampling gas chamber 13.

[0040] Step 6: Continue to pull the piston handle 7 so that the piston body 5 reaches the position of the sliding valve core 20. The piston rod pushes the sliding valve core 20 to one side of the rear cover 3. The vacuum balance valve 16 is closed and the atmospheric valve 17 is opened. The balance gas chamber 12 is connected to the outside. The gas pressure in the balance gas chamber 12 is balanced with the external gas pressure. The gas pressure in the balance gas chamber 12 is greater than the gas pressure in the sampling gas chamber 13.

[0041] Step 7: Push the piston handle 7. Since the air pressure in the sampling gas chamber 13 is greater than that in the balance gas chamber 12 at this time, the pushing process is less strenuous. As the piston rod 6 moves towards the front cover 2, the space of the sampling gas chamber 13 is compressed and the air pressure increases. Under the action of air pressure, the vacuum one-way valve 15 is closed and the exhaust one-way valve 14 is opened, and the sampling gas chamber 13 is connected to the sampling bag. Before the push plate 10 reaches the position of the sliding valve core 20, the vacuum balance valve 16 remains closed and the air vent valve 17 remains open. The air pressure in the sampling gas chamber 13 and the balance gas chamber 12 remains balanced, eliminating the pressure difference at both ends of the piston body 5, so that the gas sample in the sampling gas chamber 13 can be smoothly filled into the gas sampling bag 30.

[0042] Step 8: Continue to push the piston handle 7 so that the push plate 10 reaches the position of the sliding valve core 20. The push plate 10 pushes the sliding valve core 20 towards the front cover 2 side.

[0043] Step 9: Repeat steps 5-8 in a loop to collect gas samples from the ultra-high negative pressure gas extraction pipeline 23.

Claims

1. A gas sample collection device for an ultra-high negative pressure gas extraction pipeline, comprising a piston cylinder (1) and a piston (4); a front end cap (2) is provided at one end of the piston cylinder (1), and a rear end cap (3) is provided at the other end; the piston (4) includes a piston rod (6) passing through a guide hole (9), one end of the piston rod (6) is connected to the piston body (5) and extends into the piston cylinder (1), and the other end is connected to the piston handle (7) and extends out of the piston cylinder (1), wherein the shape and size of the piston body (5) are matched with those of the piston cylinder (1), characterized in that: The space enclosed by the piston body (5), the front end cap (2), and the piston cylinder (1) constitutes the sampling gas chamber (13). An exhaust check valve (14) and a vacuum check valve (15) are fixedly installed on the side wall of the sampling gas chamber (13). The exhaust check valve (14) allows gas to flow from inside the sampling gas chamber (13) to outside and prevents gas from flowing from outside the sampling gas chamber (13) into the sampling gas chamber (13). The vacuum check valve (15) allows gas to flow from outside the sampling gas chamber (13) into the sampling gas chamber (13) and prevents gas from flowing into the sampling gas chamber (13). Gas flows out from inside the sampling gas chamber (13) to outside the sampling gas chamber (13); the space enclosed by the piston body (5), the rear end cover (3), and the piston cylinder (1) constitutes the balance gas chamber (12). The side wall of the balance gas chamber (12) is fixedly equipped with a large air valve (17) and a vacuum balance valve (16); when the piston (4) moves to one end of the front end cover (2), the vacuum balance valve (16) opens and the large air valve (17) closes; when the piston (4) moves to one end of the front end cover (2), the vacuum balance valve (16) closes and the large air valve (17) opens. The vacuum balance valve (16) includes a hollow valve body (18) and a hollow nozzle (19). The valve body (18) and the nozzle (19) are fixedly connected or integrally formed. The hollow parts of the valve body (18) and the hollow parts of the nozzle (19) are arranged perpendicularly to each other to form a "+" shape. The upper part of the nozzle (19) extends out of the piston cylinder (1) through the side wall of the piston cylinder (1), and the lower part of the nozzle (19) passes through the valve body (18). The hollow part inside the valve body (18) is provided with a sliding valve core (20) with a length greater than the length of the valve body (18). The sliding valve core (20) can slide along the axial direction of the piston cylinder (1) inside the valve body (18). The middle part of the sliding valve core (20) is also provided with a connecting hole (22). The size of the connecting hole (22) matches the inner diameter of the nozzle (19). When the sliding valve core (20) slides to the side near the front cover (2), the position of the connecting hole (22) corresponds exactly to the position of the air nozzle (19), and the vacuum balance valve (16) opens. When the sliding valve core (20) slides to the side near the rear cover (3), the position of the connecting hole (22) and the position of the air nozzle (19) are offset from each other, and the vacuum balance valve (16) closes. The structure of the air vent valve (17) is symmetrically arranged with the structure of the vacuum balance valve (16). When the sliding valve core (20) slides to the side near the front cover (2), the position of the connecting hole (22) and the position of the air nozzle (19) are offset from each other, and the vacuum balance valve (16) closes. When the sliding valve core (20) slides to the side near the rear cover (3), the position of the connecting hole (22) corresponds exactly to the position of the air nozzle (19), and the vacuum balance valve (16) opens.

2. The gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to claim 1, characterized in that: When the sliding valve core (20) slides to the side near the front end cover (2), the end of the sliding valve core (20) near the front end cover (2) extends out of the valve body (18), and the end near the rear end cover (3) is just flush with the valve body (18); when the sliding valve core (20) slides to the side near the rear end cover (3), the end of the sliding valve core (20) near the rear end cover (3) extends out of the valve body (18), and the end near the front end cover (2) is just flush with the valve body (18).

3. The gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to claim 1, characterized in that: The piston rod (6) is fixedly connected to a push plate (10) in the middle. The push plate (10) is arranged in the balance air chamber (12). When the piston body (5) moves to one end of the front cover (2), the push plate (10) pushes the two sliding valve cores (20) to slide towards the front cover (2), the vacuum balance valve (16) opens and the air vent valve (17) closes. When the push plate (10) moves to one end of the front cover (2), the piston body (5) pushes the two sliding valve cores (20) to slide towards the rear cover (3), the vacuum balance valve (16) closes and the air vent valve (17) opens. The push plate (10) is also provided with several through holes (11) to ensure the air pressure balance on both sides of the push plate (10).

4. The gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to claim 3, characterized in that: The size of the push plate (10) matches the inner diameter of the piston cylinder (1), and it supports and guides the piston rod (6).

5. A gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to any one of claims 1-3, characterized in that: Piston rings (8) are provided along the circumference of the piston body (5).

6. A gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to any one of claims 1-3, characterized in that: Limiting blocks (21) are also provided at both ends of the valve body (18) to limit the stroke of the sliding valve core (20).

7. A gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to any one of claims 1-3, characterized in that: The front cover (2) is a cylindrical structure with one end closed and the other end open. The inner diameter of the front cover (2) matches the outer diameter of the piston cylinder (1). The open end of the front cover (2) is threaded to one end of the piston cylinder (1) or integrally formed. The inner diameter of the rear cover (3) matches the outer diameter of the piston cylinder (1). The open end of the rear cover (3) is threaded to the other end of the piston cylinder (1) or integrally formed.

8. The gas sample collection device for an ultra-high negative pressure gas extraction pipeline according to claim 7, characterized in that: The rear end cover (3) has a guide hole (9) centered along the axial direction inside. The size of the guide hole (9) matches the size of the piston rod (6). A graphite sleeve is embedded in the guide hole (9).

9. A method for collecting ultra-high negative pressure gas samples, implemented using the device described in claim 1, characterized in that, Includes the following steps: Step 1: Set up a balancing interface (24) and a sampling interface (25) in the gas extraction pipeline (23). The balancing interface (24) is equipped with a balancing ball valve (26) and connected to the balancing pipe (27). The sampling interface (25) is equipped with a sampling ball valve (28) and connected to the sampling pipe (29). The balancing ball valve (26) and the sampling ball valve (28) are kept closed. Step 2: Connect the vacuum balancing valve (16) to the balancing interface (24) through the balancing pipe (27); connect the vacuum one-way valve (15) to the negative pressure sampling interface (25) through the negative pressure sampling pipe (29); connect the exhaust one-way valve (14) to the gas sampling bag (30) through the gas sample output pipe; Step 3: Push the piston handle (7) to move the piston body (5) to the front cover (2). At this time, the pusher (10) pushes the sliding valve core (20) to the side of the front cover (2), the vacuum balance valve (16) opens and the atmospheric valve (17) closes. Step 4: Open the balance ball valve (26) and the sampling ball valve (28). At this time, the balance gas chamber (12) is connected to the gas extraction pipeline (23). The gas pressure in the balance gas chamber (12) is equal to the gas pressure in the extraction pipeline. The gas pressure in the balance gas chamber (12) is less than the gas pressure in the sampling gas chamber (13). Step 5: Pull the piston handle (7), the piston rod (6) moves towards the rear end cover (3), the space of the sampling gas chamber (13) increases and the gas pressure decreases, the vacuum check valve (15) opens and the exhaust check valve (14) closes, the sampling gas chamber (13) is connected to the gas extraction pipeline (23), the vacuum balance valve (16) remains open and the gas vent valve (17) remains closed before the piston body (5) reaches the position of the sliding valve core (20), the gas pressure in the sampling gas chamber (13), the extraction pipeline and the balance gas chamber (12) remains balanced, and the gas sample in the gas extraction pipeline (23) is filled into the sampling gas chamber (13); Step 6: Continue to pull the piston handle (7) so that the piston body (5) reaches the position of the sliding valve core (20). The piston rod pushes the sliding valve core (20) to the side of the rear cover (3), and the vacuum balance valve (16) closes and the atmospheric vent valve (17) opens. Step 7: Push the piston handle (7), and the piston rod (6) moves towards the front cover (2). The space of the sampling gas chamber (13) is compressed and the gas pressure increases. Under the action of gas pressure, the vacuum check valve (15) closes and the exhaust check valve (14) opens. The sampling gas chamber (13) is connected to the sampling bag. Before the push plate (10) reaches the position of the sliding valve core (20), the vacuum balance valve (16) remains closed and the gas vent valve (17) remains open. The gas sample in the sampling gas chamber (13) is filled into the gas sampling bag (30). Step 8: Continue to push the piston handle (7) so that the push plate (10) reaches the position of the sliding valve core (20). The push plate (10) pushes the sliding valve core (20) towards the front cover (2) side. Step 9: Repeat steps 5-8.

Images