A closed automatic sampling system and method

Abstract

The present invention relates to a closed automatic sampling system and method. It comprises a cylinder piston chamber, a cylinder sealing chamber, a cylinder sampling chamber and a sampling valve core; the cylinder piston chamber is provided with a first pressure gas source inlet, the cylinder sealing chamber is provided with a second pressure gas source inlet, the cylinder sampling chamber is provided with a purge gas source inlet and a medium outlet, a piston is provided at one end of the sampling valve core and a sampling groove is provided at the other end; the cylinder piston chamber, the cylinder sealing chamber and the cylinder sampling chamber are sealed and connected in sequence, forming a closed cavity inside, the sampling valve core is sealed and installed in the closed cavity, and the sampling valve core piston is located in the cylinder piston chamber; the first pressure gas source inlet and the second pressure gas source inlet are respectively connected to the pressure gas source, the purge gas source inlet is connected to the purge gas source, and the medium outlet is connected to the sampling bottle. The present invention realizes automatic sampling in a closed state; and the sampling bottle is easy to load and unload, avoiding leakage at the joint.

Description

Technical Field

[0001] The present invention relates to the technical field of sampling various toxic, harmful, flammable and explosive media in the petrochemical industry, and in particular to a closed automatic sampling system and method. Background Art

[0002] Frequent sampling of various toxic, harmful, flammable and explosive media is required in petrochemical production. Ethylene is the core of the entire petrochemical industry and occupies an unshakable position in a country's national economy. The development of the ethylene industry has been regarded as one of the important indicators of a country's petrochemical development level in the world. The sampling system used in the ethylene plant is the core of the sampling equipment and the key to quality inspection. It plays a very important role in the petrochemical industry.

[0003] However, the sampling devices for toxic, harmful, flammable and explosive media, especially ethylene, in petrochemical production are generally not sealed tightly, and automatic sampling cannot be achieved. In addition, the inconvenience of loading and unloading sampling bottles and the leakage problems at the joints have not been well solved. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a closed automatic sampling system and method, which realizes automatic sampling in a closed state, and the sampling bottle is easy to load and unload, avoiding leakage at the joint.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A closed automatic sampling system comprises a cylinder piston chamber, a cylinder sealing chamber, a cylinder sampling chamber and a sampling valve core; the cylinder piston chamber is provided with a first pressure gas source inlet, the cylinder sealing chamber is provided with a second pressure gas source inlet, the cylinder sampling chamber is provided with a purge gas source inlet and a medium outlet, a piston is provided at one end of the sampling valve core and a sampling groove is provided at the other end; the cylinder piston chamber, the cylinder sealing chamber and the cylinder sampling chamber are sealed and connected in sequence to form a closed chamber inside, the sampling valve core is sealed and installed in the closed chamber, and the sampling valve core piston is located in the cylinder piston chamber; the first pressure gas source inlet and the second pressure gas source inlet are respectively connected to the pressure gas source, the purge gas source inlet is connected to the purge gas source, and the medium outlet is connected to the sampling bottle.

[0007] It also includes pneumatic quick connectors, which are respectively fixedly connected to the first pressure air source inlet, the second pressure air source inlet and the purge air source inlet, and the connection method is threaded sealing; the first pressure air source inlet, the second pressure air source inlet and the purge air source inlet are respectively connected to their own air sources through pneumatic quick connectors.

[0008] It also includes an open and close quick connector; the open and close quick connector includes a quick opening female head and a quick opening male head, both of which are provided with a top valve core and a reset spring, the quick opening female head is provided with a protective gas outlet and a sealing groove, the quick opening female head is connected to the medium outlet, and the quick opening male head is connected to the sampling bottle; after the quick opening male head is inserted into the quick opening female head, the contact surface is sealed by a sealing ring, the two top valve cores interact with each other, and the quick opening male head is connected to the inner cavity of the quick opening female head; after the quick opening male head leaves the quick opening female head, the top valve core is reset under the action of the reset spring, and the quick opening male head and the quick opening female head are closed respectively.

[0009] A first pressure gas source inlet is provided on one end face of the cylinder piston cavity, the first pressure gas source inlet is a through hole, a buffer mechanism is provided at the first pressure gas source inlet in the cylinder piston cavity, and a sealing groove is provided on the other end face of the cylinder piston cavity.

[0010] A second pressure gas source inlet is arranged on the side wall of the cylinder body sealing cavity, the second pressure gas source inlet is connected with one end surface of the cylinder body sealing cavity through a connecting hole, and sealing grooves are arranged on the inner wall and the two end surfaces.

[0011] A purge gas source inlet and a medium outlet are provided on the side wall of the cylinder sampling cavity, both of which are through holes, and both of which are provided with process chamfers; a sealing groove is provided on one end face of the cylinder sampling cavity, a process chamfer is provided on the other end face, and a sealing groove is provided on the inner wall.

[0012] The sampling valve core comprises a piston, a connecting rod and a sampling rod; the connecting rod and the sampling rod are integrated, and the connecting rod and the piston are connected by threads; a sealing groove is arranged on the side wall of the piston, and a sealing groove, a guide groove and a sampling groove are arranged on the sampling rod.

[0013] The sampling valve core piston is sealed with the inner wall of the cylinder piston cavity through a sealing ring, the connecting rod is sealed with the inner wall of the cylinder sealing cavity through a sealing ring, and the sampling rod is sealed with the inner wall of the cylinder sampling cavity through a sealing ring.

[0014] The cylinder piston cavity and the cylinder sealing cavity are clamped together by a clamp joint, and the end face of the cylinder piston cavity is compressed and sealed together with the end face of the cylinder sealing cavity by a sealing ring; the cylinder sealing cavity and the cylinder sampling cavity are clamped together by a clamp joint, and the end face of the cylinder sealing cavity is compressed and sealed together with the end face of the cylinder sampling cavity by a sealing ring.

[0015] A sealed automatic sampling method comprises the following steps:

[0016] Step 1: Connect the first pressure gas source inlet to the first pressure gas source through a pneumatic quick connector, connect the second pressure gas source inlet to the second pressure gas source through a pneumatic quick connector, connect the purge gas source inlet to the purge gas source through a pneumatic quick connector, and connect the medium outlet to the sampling bottle through an open and close quick connector;

[0017] Step 2: introducing purge gas through the purge gas source inlet for purge;

[0018] Step 3: The pressurized gas is introduced through the first pressure gas source inlet. The pressurized gas flows through the cylinder piston cavity to push the left end surface of the piston, driving the sampling valve core to move to the right, pushing the gas in the cavity through the connecting hole to the second pressure gas source inlet and then discharged, thereby causing the sampling rod of the sampling valve core to extend out of the device and enter the sampling medium. The medium flows into the sampling slot and then into the sampling slot;

[0019] Step 4: After the medium flows into the sampling slot, the pressurized gas is introduced through the second pressure gas source inlet. The pressurized gas flows through the connecting hole to push the right end surface of the piston, driving the sampling valve core to move to the left, pushing the gas in the cavity to be discharged after passing through the first pressure gas source inlet, and then the sampling rod of the sampling valve core is retracted into the device to the limit position so that the sampling slot is facing the medium outlet. Under the action of gravity, the medium flows into the sampling bottle from the medium outlet; this is a sampling cycle, and the above operation is repeated until the required sample amount is taken;

[0020] Step 5: After sampling is completed, purge gas is introduced through the purge gas source inlet for purging.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The present invention comprises a cylinder piston chamber, a cylinder sealing chamber, a cylinder sampling chamber and a sampling valve core, the first pressure gas source inlet of the cylinder piston chamber and the second pressure gas source inlet of the cylinder sealing chamber are respectively connected to the pressure gas source, the purge gas source inlet of the cylinder sampling chamber is connected to the purge gas source, and the medium outlet of the cylinder sampling chamber is connected to the sampling bottle;

[0023] The pressure gas enters from the inlet of the first pressure gas source, drives the sampling valve core to move to the right, and makes the sampling rod of the sampling valve core extend out of the device and enter the sampling medium. The medium flows into the sampling slot from the sampling slot. After the medium flows into the sampling slot, the pressure gas is introduced through the inlet of the second pressure gas source. The pressure gas drives the sampling valve core to move to the left, and then the sampling head is retracted into the device to the limit position so that the sampling slot is directly opposite to the medium outlet. Under the action of gravity, the medium flows into the sampling bottle from the medium outlet. This is a sampling cycle, and the above operation is repeated until the required sample amount is obtained.

[0024] The present invention realizes automatic sampling in a closed state, improves sampling operation efficiency, avoids direct contact between operators and toxic and harmful media, ensures the personal safety of operators, avoids leakage of toxic and harmful media, and is beneficial to environmental protection.

[0025] 2) The present invention is provided with a purge gas source inlet, which is connected to the purge gas source through a pneumatic quick connector. The purge is performed before and after sampling respectively, with the purpose of removing the residual medium in the device to avoid contamination of the device, providing a clean environment for the next sampling, and ensuring the accuracy of the sampling medium.

[0026] 3) The sampling valve core piston of the present invention is provided with a sealing groove on the side wall, and the sampling rod is provided with a sealing groove, a guide groove and a sampling groove; the sampling valve core piston is sealed with the inner wall of the cylinder piston cavity through a sealing ring, the connecting rod is sealed with the inner wall of the cylinder sealing cavity through a sealing ring, and the sampling rod is sealed with the inner wall of the cylinder sampling cavity through a sealing ring; each component is tightly sealed to avoid leakage of toxic and harmful media.

[0027] 4) The cylinder piston chamber and the cylinder sealing chamber of the present invention are clamped together by a clamp joint, and the end face of the cylinder piston chamber is compressed and sealed with the end face of the cylinder sealing chamber by a sealing ring; the cylinder sealing chamber and the cylinder sampling chamber are clamped together by a clamp joint, and the end face of the cylinder sealing chamber is compressed and sealed with the end face of the cylinder sampling chamber by a sealing ring; each component is tightly sealed to avoid leakage of toxic and harmful media.

[0028] 5) A buffer structure is provided at the inlet of the first pressure gas source in the cylinder piston cavity to prevent the piston from colliding with the inner end surface of the cylinder piston cavity.

[0029] 6) The medium outlet of the present invention is provided with a process chamfer, and the other end surface of the cylinder sampling cavity is provided with a process chamfer; when the sampling valve core moves back and forth, it ensures sealing while also avoiding damage to the sampling port sealing ring and the sampling port guide ring.

[0030] 7) The open-and-close quick connector includes a quick-open female head and a quick-open male head. After the quick-open male head is inserted into the quick-open female head, the contact surface is sealed by a sealing ring, and the two opposing valve cores interact with each other, so that the inner cavities of the quick-open male head and the quick-open female head are connected; after the quick-open male head leaves the quick-open female head, the opposing valve core is reset by the action of the reset spring, and the quick-open male head and the quick-open female head are closed respectively; the plug-in connection makes the sampling bottle loading and unloading convenient and quick, and the quick-open male head and the quick-open female head are closed respectively before and after loading and unloading, which effectively avoids the leakage of toxic and harmful media at the joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic cross-sectional view of the working state and structure of the present invention;

[0032] Figure 2 It is a schematic cross-sectional view of the structure of the piston of the present invention at the right extreme position (excluding the open-close quick connector);

[0033] Figure 3 It is a schematic cross-sectional view of the structure of the piston of the present invention at the left extreme position (excluding the open-close quick connector);

[0034] Figure 4 It is a schematic cross-sectional view of the open and close quick connector structure of the present invention.

[0035] In the figure: 1-cylinder piston chamber 2-cylinder sealing chamber 3-cylinder sampling chamber 4-sampling valve core 5-open and close quick connector 6-pneumatic quick connector 7-ethylene device pipeline 8-ethylene 9-sampling bottle 10-clamp joint 11-first pressure gas source inlet 12-buffer structure 13-O-type sealing ring 21-second pressure gas source inlet 22-connecting hole 23-Y-type sealing ring 31-nitrogen purge port 32-medium outlet 33-sampling slot process chamfer 34-sampling port process chamfer 35-valve core sealing ring 41-piston 42-connecting rod 43-sampling rod 44-piston seal 45-sampling port sealing ring 46-sampling port guide ring 47-sampling slot 51-quick open female head 52-quick open male head 53-top valve core 54-reset spring 55-protection gas outlet 56-sealing ring 57-sleeve steel ball DETAILED DESCRIPTION

[0036] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0037] [Example]:

[0038] like Figures 1 to 3 The enclosed automatic sampling system shown is a enclosed automatic sampling system for a large ethylene plant in the petrochemical industry, comprising a cylinder piston chamber 1, a cylinder sealing chamber 2, a cylinder sampling chamber 3, a sampling valve core 4, an open-close quick connector 5 and a pneumatic quick connector 6.

[0039] The left end face of the cylinder piston chamber 1 is provided with a first pressure gas source inlet 11, which is a through hole. A buffer structure 12 is provided at the first pressure gas source inlet 11 in the cylinder piston chamber. The buffer structure 12 is a process groove connected to the end of the first pressure gas source inlet 11. The buffer structure 12 prevents the piston 41 from colliding with the inner end face of the cylinder piston chamber 1. The right end face of the cylinder piston chamber 1 is provided with a sealing groove adapted to the O-ring 13.

[0040] A second pressure gas source inlet 21 is provided on the side wall of the cylinder body sealing chamber 2. The second pressure gas source inlet 21 is not a through hole. The second pressure gas source inlet 21 is connected to the left end face of the cylinder body sealing chamber 2 through a connecting hole 22. The inner wall of the cylinder body sealing chamber 2 is provided with a sealing groove adapted to the Y-type sealing ring 23; the left and right end faces of the cylinder body sealing chamber 2 are both provided with sealing grooves adapted to the O-type sealing ring 13.

[0041] A nitrogen purge port 31 and a medium outlet 32 ​​are provided on the side wall of the cylinder sampling chamber 3. Both the nitrogen purge port 31 and the medium outlet 32 ​​are through holes. A sampling groove process chamfer 33 is provided at the medium outlet 32 ​​and the nitrogen purge port 31. A sealing groove adapted to the O-ring 13 is provided on the left end face of the cylinder sampling chamber 3. A sampling port process chamfer 34 is provided on the right end face of the cylinder sampling chamber 3. A sealing groove adapted to the valve core sealing ring 35 is provided on the inner wall of the cylinder sampling chamber 3. A sampling groove process chamfer 33 is provided at the medium outlet 32 ​​and the nitrogen purge port 31. A sampling port process chamfer 34 is provided on the right end face of the cylinder sampling chamber 3. When the sampling valve core 4 moves back and forth, the sealing is ensured while avoiding damage to the sampling port sealing ring 45 and the sampling port guide ring 46.

[0042] The sampling valve core 4 includes a piston 41, a connecting rod 42 and a sampling rod 43; the connecting rod 42 and the sampling rod 43 are an integral structure, and the connecting rod 42 and the piston 41 are connected and sealed by threads. A sealing groove adapted to the piston seal 44 is provided on the side wall of the piston 41, and a sealing groove adapted to the sampling port sealing ring 45, a guide groove adapted to the sampling port guide ring 46, and a sampling groove 47 are provided on the sampling rod 43.

[0043] like Figure 4 As shown, the open-close quick connector 5 includes a quick-open female head 51 and a quick-open male head 52. The quick-open female head 51 and the quick-open male head 52 are both provided with a top valve core 53 and a reset spring 54. The quick-open female head 51 is provided with a protective gas outlet 55 and a sealing groove. The quick-open female head 51 is connected to the medium outlet 32, and the quick-open male head 52 is connected to the sampling bottle 9. After the quick-open male head 52 is inserted into the quick-open female head 51, it is clamped by a ferrule steel ball 57, and the contact surface is sealed by a sealing ring 56. A straight mouth structure is provided in the inner hole of the quick-open female head 51, and an O-ring is attached to the outer cylindrical surface to ensure the sealing effect during docking. The two top valve cores 53 interact with each other, and the quick-open male head 51 is connected to the inner cavity of the quick-open female head 52. After the quick-open male head 52 is pulled out of the quick-open female head 51, the top valve core 53 is reset under the action of the reset spring 54, and the quick-open male head 51 and the quick-open female head 52 are closed respectively.

[0044] The quick-open male connector 51 is inserted into the quick-open female connector 52 to complete the connection, and the quick-open male connector 51 is pulled out to complete the disassembly, so that the sampling bottle 9 is convenient and quick to load and unload. Moreover, the quick-open male connector 51 and the quick-open female connector 52 are both closed before and after loading and unloading, and the quick-open male connector 51 and the quick-open female connector 52 are connected only when connected, and they are closed before and after loading and unloading, which effectively avoids the leakage of toxic and harmful media at the joint.

[0045] like Figures 1 to 3As shown, the right end of the cylinder piston chamber 1 and the left end of the cylinder sealing chamber 2 are clamped together by a clamp joint 10, and the right end face of the cylinder piston chamber 1 is pressed and sealed with the left end face of the cylinder sealing chamber 2 through an O-type sealing ring 13. The right end of the cylinder sealing chamber 2 and the left end of the cylinder sampling chamber 3 are clamped together by a clamp joint 10, and the right end face of the cylinder sealing chamber 2 is pressed and sealed with the left end face of the cylinder sampling chamber 3 through an O-type sealing ring 13. All components are tightly sealed to prevent leakage of toxic and harmful media.

[0046] The sampling valve core piston 41 is installed in the cylinder piston chamber 1, and the sampling valve core piston 41 is sealed with the inner wall of the cylinder piston chamber 1 through the piston seal 44. The connecting rod 42 is installed in the cylinder sealing chamber 2, and the connecting rod 42 is sealed with the inner wall of the cylinder sealing chamber 2 through the Y-shaped sealing ring 23. The sampling rod 43 is installed in the cylinder sampling chamber 3, and the sampling rod 43 is sealed with the inner wall of the cylinder sampling chamber 3 through the valve core sealing ring 45, the sampling port guide ring 46, and the sampling port sealing ring 45. Each component is tightly sealed to avoid leakage of toxic and harmful media.

[0047] The pneumatic quick connector 6 is an existing product, and the PC10-02 type can be used. The three pneumatic quick connectors 6 are respectively fixed to the first pressure gas source inlet 11, the second pressure gas source inlet 21 and the nitrogen purge port 31. The first pressure gas source inlet 11 is connected to the first pressure gas source through the pneumatic quick connector 6, and the second pressure gas source inlet 21 is connected to the second pressure gas source through the pneumatic quick connector 6. The nitrogen purge port 31 is connected to the nitrogen gas source through the pneumatic quick connector 6. Nitrogen is used to purge before and after sampling. The purpose is to remove the residual medium in the device to avoid contamination of the device, and also to provide a clean environment for the next sampling to ensure the accuracy of the sampling medium. The medium outlet 32 ​​is connected to the sampling bottle 9 through the open and close quick connector 5.

[0048] like Figures 1 to 3 As shown, ethylene 8 is installed in the ethylene device pipeline 7, and a sealed automatic sampling method includes the following steps:

[0049] Step 1: Connect the first pressure gas source inlet 11 to the first pressure gas source through the pneumatic quick connector 6, connect the second pressure gas source inlet 21 to the second pressure gas source through the pneumatic quick connector 6, connect the nitrogen purge port 31 to the nitrogen gas source through the pneumatic quick connector 6, and connect the medium outlet 32 ​​to the sampling bottle 9 through the open and close quick connector 5.

[0050] Step 2: introducing nitrogen through the nitrogen purge port 31 for purge;

[0051] Step 3: Figure 2As shown, as shown by the arrow, the pressure gas is introduced through the first pressure gas source inlet 11, and the pressure gas flows through the cylinder sealing cavity 1 to push the left end surface of the piston 41, driving the sampling valve core 4 to move to the right, pushing the gas in the cavity through the connecting hole 22 to the second pressure gas source inlet 21 and then discharged, thereby making the sampling rod 43 of the sampling valve core 4 extend out of the device and enter the ethylene 8. As shown by the arrow, the ethylene 8 flows into the sampling groove 47 from the sampling notch;

[0052] Step 4: Figure 3 As shown, after ethylene 8 flows into the sampling groove 47, pressure gas is introduced through the second pressure gas source inlet 21, and the pressure gas flows through the connecting hole 22 to push the right end surface of the piston 41, driving the sampling valve core 4 to move to the left, pushing the gas in the cavity to be discharged after passing through the first pressure gas source inlet 11, and then the sampling rod 43 of the sampling valve core 4 is retracted into the device to the limit position so that the sampling groove 47 is directly opposite to the medium outlet 32. Under the action of gravity, ethylene 8 flows into the sampling bottle 9 from the medium outlet 32; this is a sampling cycle, and the above operation is repeated until the required sample amount is obtained;

[0053] Step 5: After sampling is completed, nitrogen is introduced through the nitrogen purge port 31 for purging. Purging before and after sampling is performed to remove the residual medium in the device to avoid contamination of the device, and to provide a clean environment for the next sampling to ensure the accuracy of the sampling medium.

[0054] The present invention realizes automatic sampling in a closed state; and the sampling bottle 9 is easy to load and unload, and the quick-open male head 51 and the quick-open female head 52 are both closed before and after loading and unloading, thereby avoiding leakage at the joint.

[0055] The above embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are conventional methods unless otherwise specified.

Claims

1. A closed automatic sampling system, characterized in that: It includes a cylinder piston chamber, a cylinder sealing chamber, a cylinder sampling chamber and a sampling valve core; the cylinder piston chamber is provided with a first pressure gas source inlet, the cylinder sealing chamber is provided with a second pressure gas source inlet, the cylinder sampling chamber is provided with a purge gas source inlet and a medium outlet, and a piston is provided at one end of the sampling valve core and a sampling groove is provided at the other end; the cylinder piston chamber, the cylinder sealing chamber and the cylinder sampling chamber are sealed and connected in sequence to form a closed chamber inside, the sampling valve core is sealed and installed in the closed chamber, and the sampling valve core piston is located in the cylinder piston chamber; the first pressure gas source inlet and the second pressure gas source inlet are respectively connected to the pressure gas source, the purge gas source inlet is connected to the purge gas source, and the medium outlet is connected to the sampling bottle; The pressure gas is introduced through the first pressure gas source inlet, so that the sampling rod of the sampling valve core extends out of the device and enters the sampling medium. After the medium flows into the sampling tank, the pressure gas is introduced through the second pressure gas source inlet, so that the sampling rod of the sampling valve core retracts into the device. Under the action of gravity, the medium flows into the sampling bottle from the medium outlet; It also includes pneumatic quick connectors, which are respectively fixed to the first pressure gas source inlet, the second pressure gas source inlet and the purge gas source inlet, and the connection method is threaded sealing; the first pressure gas source inlet, the second pressure gas source inlet and the purge gas source inlet are respectively connected to their respective gas sources through the pneumatic quick connectors; A first pressure gas source inlet is provided on one end surface of the cylinder piston cavity, the first pressure gas source inlet is a through hole, a buffer mechanism is provided at the first pressure gas source inlet in the cylinder piston cavity, and a sealing groove is provided on the other end surface of the cylinder piston cavity; A second pressure gas source inlet is provided on the side wall of the cylinder body sealing cavity, the second pressure gas source inlet is connected to one end surface of the cylinder body sealing cavity through a connecting hole, and sealing grooves are provided on the inner wall and the two end surfaces; The side wall of the cylinder sampling cavity is provided with a purge gas source inlet and a medium outlet, both of which are through holes, and both of which are provided with process chamfers; a sealing groove is provided on one end surface of the cylinder sampling cavity, a process chamfer is provided on the other end surface, and a sealing groove is provided on the inner wall; The sampling valve core comprises a piston, a connecting rod and a sampling rod; the connecting rod and the sampling rod are integrated, and the connecting rod and the piston are connected by threads; a sealing groove is provided on the side wall of the piston, and a sealing groove, a guide groove and a sampling groove are provided on the sampling rod; The sampling valve core piston is sealed with the inner wall of the cylinder piston cavity through a sealing ring, the connecting rod is sealed with the inner wall of the cylinder sealing cavity through a sealing ring, and the sampling rod is sealed with the inner wall of the cylinder sampling cavity through a sealing ring; The cylinder piston cavity and the cylinder sealing cavity are clamped together by a clamp joint, and the end face of the cylinder piston cavity is compressed and sealed together with the end face of the cylinder sealing cavity by a sealing ring; the cylinder sealing cavity and the cylinder sampling cavity are clamped together by a clamp joint, and the end face of the cylinder sealing cavity is compressed and sealed together with the end face of the cylinder sampling cavity by a sealing ring.

2. A closed automatic sampling system according to claim 1, characterized in that: It also includes an open-and-close quick connector; the open-and-close quick connector includes a quick-open female head and a quick-open male head, both of which are provided with a top valve core and a reset spring, the quick-open female head is provided with a protective gas outlet and a sealing groove, the quick-open female head is connected to the medium outlet, and the quick-open male head is connected to the sampling bottle; After the quick-open male connector is inserted into the quick-open female connector, the contact surface is sealed by the sealing ring, the two opposing valve cores interact with each other, and the quick-open male connector is connected to the inner cavity of the quick-open female connector; After the quick-opening male head leaves the quick-opening female head, the top valve core is reset under the action of the reset spring, and the quick-opening male head and the quick-opening female head are closed respectively.

3. A sealed automatic sampling method based on a closed automatic sampling system according to claim 1 or 2, characterized in that: The steps include: Step 1: Connect the first pressure gas source inlet to the first pressure gas source through a pneumatic quick connector, connect the second pressure gas source inlet to the second pressure gas source through a pneumatic quick connector, connect the purge gas source inlet to the purge gas source through a pneumatic quick connector, and connect the medium outlet to the sampling bottle through an open and close quick connector; Step 2: introducing purge gas through the purge gas source inlet for purge; Step 3: The pressurized gas is introduced through the first pressure gas source inlet. The pressurized gas flows through the cylinder piston cavity to push the left end surface of the piston, driving the sampling valve core to move to the right, pushing the gas in the cavity through the connecting hole to the second pressure gas source inlet and then discharged, thereby causing the sampling rod of the sampling valve core to extend out of the device and enter the sampling medium. The medium flows into the sampling slot and then into the sampling slot; Step 4: After the medium flows into the sampling slot, the pressurized gas is introduced through the second pressure gas source inlet. The pressurized gas flows through the connecting hole to push the right end surface of the piston, driving the sampling valve core to move to the left, pushing the gas in the cavity to be discharged after passing through the first pressure gas source inlet, and then the sampling rod of the sampling valve core is retracted into the device to the limit position so that the sampling slot is facing the medium outlet. Under the action of gravity, the medium flows into the sampling bottle from the medium outlet; this is a sampling cycle, and the above operation is repeated until the required sample amount is taken; Step 5: After sampling is completed, purge gas is introduced through the purge gas source inlet for purging.

Images