LNG (Liquefied Natural Gas) low-temperature sampling and analyzing device

Abstract

The invention relates to the technical field of LNG (Liquefied Natural Gas) sampling analysis, and discloses an LNG low-temperature sampling analysis device which comprises a gas analyzer, the gas inlet is formed in the gas analyzer; the gas storage tank is mounted on the gas analyzer and is arranged opposite to the gas inlet; the support is fixed on the gas storage tank, and a penetrating opening is formed in the support; the air pipe is fixed at the top end of the air storage tank and is communicated with the interior of the air storage tank; the valve is mounted on the air pipe; and the air supply structure is arranged in the air storage tank. Automatic sample feeding of natural gas is achieved through a mechanical structure, extraction is conducted without depending on an air pump, so that the overall cost of detection equipment is reduced, meanwhile, the design avoids the harmful effects such as noise, vibration and energy consumption possibly generated during operation of the air pump, the comfort level of the detection environment is improved, and the detection efficiency is improved. And the reliability and the stability of the equipment are further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of LNG sampling and analysis, and in particular to an LNG low-temperature sampling and analysis device. Background Art

[0002] The LNG cryogenic sampling and analysis device is mainly composed of a sampling probe, a transmission pipeline, a heat preservation system, a vaporizer, an analysis system, etc. The device can achieve fast and accurate sampling and analysis while maintaining the original state of the LNG sample.

[0003] After searching, the Chinese patent with publication number CN106802344A discloses a continuous sampling and analysis device for LNG loading and unloading and a method of using the same, characterized in that the sampling and analysis device includes an LNG sampling probe, a gasification device, a sampling main pipeline, a BOG return device, an online analysis device, a flow control device, a sample gas storage device, a sample cylinder filling system and a control system; the LNG sampling probe is connected to the gasification device inlet through an isolation shut-off valve and a temperature detection element, and the gasification device outlet is connected to the BOG return device through the sampling main pipeline; the gasification device outlet is also connected to the online analysis device and the flow control device through the sampling main pipeline, respectively, the flow control device is also connected to the sample gas storage device inlet, the sample gas storage device outlet is connected to the sample cylinder filling system, and the sample cylinder filling system is also connected to the BOG main pipe; the isolation shut-off valve, the temperature detection element, the sampling main pipeline, the flow control device, the sample gas storage device and the sample cylinder filling system are electrically connected to the control system respectively. The above scheme can be widely used in facilities for analyzing LNG components and calculating LNG calorific value. However, the above scheme still has the following shortcomings when actually used: The LNG analysis device proposed in the above scheme is internally provided with a sampling gas pump for extracting gas. The staff connects the sampling container to the analysis device, and the sampling gas pump extracts the gas in the sampling container. From a cost perspective, the introduction of the sampling gas pump significantly increases the production and procurement costs of the entire device. This is undoubtedly an important factor that needs to be considered for the liquefied natural gas industry that pursues cost-effectiveness. Secondly, the vibration generated by the sampling gas pump during operation poses a potential threat to the stability and reliability of the device. This vibration may not only cause the pipes and connectors inside the device to loosen, thereby affecting the accuracy of sampling and analysis, but may also accelerate the aging process of the equipment and shorten its service life.

[0004] Therefore, it is necessary to design an LNG low-temperature sampling and analysis device to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an LNG low-temperature sampling and analysis device.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: An LNG low temperature sampling and analysis device, comprising: Gas analyzers; A gas inlet, provided on the gas analyzer; A gas storage tank is installed on the gas analyzer and is arranged directly opposite to the gas inlet; A bracket is fixed on the gas storage tank, and a through hole is opened on the bracket; An air pipe, fixed to the top of the air storage tank and connected to the interior of the air storage tank; a valve, mounted on the air pipe; An air supply structure is arranged inside the air storage tank; A limiting structure, arranged on the bracket; A clamping structure is arranged on the gas analyzer and is arranged directly opposite to the gas inlet; A damping structure, arranged on the gas analyzer; The damping structure comprises: A side plate, fixed on a side of the gas analyzer; An outer cylinder is fixed on the bottom surface of the side plate, and the opening of the outer cylinder faces downward; A pressing rod is slidably disposed in the outer cylinder, the bottom end of the pressing rod extends to the outside of the outer cylinder, and the pressing rod is disposed opposite to the rotating ring; Spring 2 has one end connected to the inner top surface of the outer cylinder and the other end connected to the pressing rod.

[0007] As a preferred technical solution of the present invention, the air supply structure includes: A pull rod passes through the bottom surface of the gas storage tank and is slidably connected to the gas storage tank, and one end of the pull rod located outside the gas storage tank passes through a hole on the bracket; A sliding plug is sealingly and slidingly connected to the inside of the gas storage tank, and one end of the pull rod located inside the gas storage tank is rotatably connected to the sliding plug; Spring 1 has one end connected to the inner wall of the gas storage tank and the other end connected to the sliding plug.

[0008] As a preferred technical solution of the present invention, the limiting structure includes: A plurality of connecting rods, all fixed on the bracket; A limiting ring, fixed to one end of the plurality of connecting rods away from the bracket; A limiting opening is provided on the inner ring of the limiting ring; The limit block is fixed to one end of the pull rod located outside the gas storage tank.

[0009] As a preferred technical solution of the present invention, the clamping structure includes: two fixing rods, both fixed on the gas analyzer; A mounting ring, fixed to one end of the two fixing rods away from the gas analyzer, the mounting ring being arranged directly opposite to the gas inlet; A rotating ring, rotatably mounted on the mounting ring; A plurality of compression plates are disposed between the mounting ring and the rotating ring, and the plurality of compression plates are distributed in a circumferential array; A plurality of sliding blocks are respectively fixed on the side surfaces of the plurality of pressing sheets; A plurality of slideways are arranged on the rotating ring, the plurality of slideways are distributed in a circumferential array, and the plurality of sliders are slidably arranged in the plurality of slideways respectively; A plurality of guide blocks are respectively fixed on the side surfaces of the plurality of pressing sheets; A guide groove is provided on the side of the mounting ring, the cross section of the guide groove is a regular hexagonal structure, and each guide block is slidably arranged in the guide groove.

[0010] As a preferred technical solution of the present invention, a clamping structure and a control structure are provided below the bracket, and the clamping structure includes: A plurality of connecting rods 2, all fixed on the limiting ring; A fixing ring, fixed to one end of the plurality of connecting rods 2 away from the limiting ring; A plurality of sliding openings are provided on the outer peripheral surface of the fixing ring; A plurality of pressing plates are respectively slidably arranged in the plurality of sliding openings, and each of the pressing plates is provided with an inclined surface.

[0011] As a preferred technical solution of the present invention, the control structure includes: Two connecting rods three are both fixed on the limiting ring; A threaded barrel is fixed to one end of the two connecting rods away from the limiting ring, and the outer peripheral surface of the threaded barrel is provided with threads; A lifting sleeve, threadedly sleeved on the threaded barrel; A lifting cover is fixed on the top of the lifting sleeve, and the lifting cover is located below a plurality of pressure plates.

[0012] As a preferred technical solution of the present invention, the top opening of the lifting cover is larger than the bottom opening.

[0013] As a preferred technical solution of the present invention, a pull ring is fixed to one end of the pull rod away from the sliding plug.

[0014] As a preferred technical solution of the present invention, the outer surface of the pressing rod and the inner surface of the outer cylinder are in contact with each other.

[0015] The present invention has the following beneficial effects: 1. Automatic natural gas sampling is achieved through the mechanical structure, without relying on the air pump for extraction, thus reducing the overall cost of the detection equipment. At the same time, this design avoids the adverse effects of noise, vibration and energy consumption that may be generated when the air pump is running, which not only improves the comfort of the detection environment, but also further enhances the reliability and stability of the equipment. In addition, by accurately controlling the alignment of the limit block and the limit port, the smooth movement of the sliding plug and the pull rod is ensured, and the precise regulation of natural gas sampling is achieved, providing strong support for the efficient and accurate detection of natural gas; 2. By rotating the lifting sleeve, the lifting cover is driven to squeeze the inclined surface of the pressure plate by its movement on the threaded cylinder. Due to the special design of the lifting cover, the pressure plate can synchronously approach the pull rod and apply pressure, thereby effectively slowing down the movement speed of the pull rod and the sliding plug connected to it. This mechanism prevents the sliding plug from moving quickly under the action of the spring force, ensuring that the natural gas can enter the detection area slowly and steadily, and preventing the adverse effects that may be caused by excessive sample delivery speed. This design not only improves the accuracy and controllability of sample delivery, but also optimizes the flow state of the gas, providing more stable and reliable sample delivery conditions for natural gas detection; 3. By rotating the rotating ring, the clamping piece can open and close synchronously, which can firmly clamp the gas tank and effectively prevent the gas tank from falling off from the detection equipment, thereby ensuring the continuity and accuracy of the detection process. Secondly, by utilizing the elastic force of spring 2, the clamping rod always applies pressure to the rotating ring to prevent the accidental rotation of the rotating ring in the non-operating state. This not only enhances the safety of the equipment, but also ensures the continuous clamping effect of the clamping piece on the gas tank, avoiding the problem of clamping failure caused by loosening of the rotating ring. In summary, the clamping structure not only improves the reliability and stability of the gas tank fixation, but also enhances the overall safety and ease of operation of the equipment, providing a strong guarantee for the efficient and safe detection of natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of an LNG cryogenic sampling and analysis device proposed by the present invention; Figure 2 It is a schematic diagram of the cross-sectional structure of the gas analyzer; Figure 3 It is a structural schematic diagram of the gas storage tank; Figure 4 It is a structural schematic diagram of the gas storage tank from another perspective; Figure 5 It is a schematic diagram of the cross-sectional structure of the gas storage tank; Figure 6 for Figure 1 A magnified view of the structure at A; Figure 7for Figure 2 A magnified view of the structure at B; Figure 8 for Figure 3 A magnified view of the structure at C; Fig. 9 for Figure 4 A magnified view of the structure at D; Fig.10 for Figure 5 A magnified view of the structure at E; Fig.11 Schematic diagram of the explosion structure of the clamping structure.

[0017] In the figure: 1. gas analyzer; 2. air inlet; 3. gas storage tank; 4. bracket; 5. air pipe; 6. valve; 71. pull rod; 72. slide plug; 73. spring one; 81. connecting rod one; 82. limit ring; 83. limit opening; 84. limit block; 91. connecting rod two; 92. fixed ring; 93. slide opening; 94. pressure plate; 101. connecting rod three; 102. threaded cylinder; 103. lifting sleeve; 104. lifting cover; 111. fixed rod; 112. mounting ring; 113. rotating ring; 114. clamping plate; 115. slider; 116. slideway; 117. guide block; 118. guide groove; 121. side plate; 122. outer cylinder; 123. clamping rod; 124. spring two. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] Reference Figure 1-11 , an LNG low-temperature sampling and analysis device, including a gas analyzer 1, the specific structure and working principle of the gas analyzer 1 are not the innovative part of the present technical solution, are not shown in the figure, and will not be described in detail here; an air inlet 2 is provided on the gas analyzer 1; a gas storage tank 3 is installed on the gas analyzer 1 and is arranged directly opposite to the air inlet 2; a bracket 4 is fixed on the gas storage tank 3, and a through hole is provided on the bracket 4; an air pipe 5 is fixed on the top of the gas storage tank 3 and is connected to the inside of the gas storage tank 3; a valve 6 is installed on the air pipe 5; The LNG low-temperature sampling and analysis device also includes a gas delivery structure, which is arranged inside the gas storage tank 3. The gas delivery structure includes: a pull rod 71, which passes through the bottom surface of the gas storage tank 3 and is slidably connected to the gas storage tank 3. The end of the pull rod 71 located outside the gas storage tank 3 passes through the hole on the bracket 4, and the end of the pull rod 71 away from the sliding plug 72 is fixed with a pull ring; the sliding plug 72 is sealed and slidably connected to the inside of the gas storage tank 3, and the end of the pull rod 71 located inside the gas storage tank 3 is rotatably connected to the sliding plug 72; a spring 73, one end of which is connected to the inner wall of the gas storage tank 3 and the other end is connected to the sliding plug 72. The staff opens the valve 6 to allow the natural gas to be ejected through the air pipe 5 and enter the inside of the gas analyzer 1. During the process of discharging the natural gas, the sliding plug 72 will move under the elastic force of the spring 73 and push the natural gas in the gas storage tank 3 to realize the automatic sampling of the natural gas; The LNG low-temperature sampling and analysis device also includes a limiting structure, which is arranged on the bracket 4. The limiting structure includes: a plurality of connecting rods 81, all fixed on the bracket 4; a limiting ring 82, fixed to the end of the plurality of connecting rods 81 away from the bracket 4; a limiting opening 83, opened on the inner ring of the limiting ring 82; a limiting block 84, fixed to the end of the pull rod 71 located outside the gas storage tank 3. Before sampling, the staff first pulls the pull rod 71, and uses the pull rod 71 to drive the sliding plug 72 to move. In the process of pulling the pull rod 71, the staff needs to align the limiting block 84 with the limiting opening 83, and make the limiting block 84 pass through the limiting opening 83. When the limit block 84 passes through the limit opening 83, the staff rotates the pull rod 71 to rotate the limit block 84 accordingly, until the limit block 84 and the limit opening 83 are staggered with each other. At this time, the limit block 84 cannot pass through the limit opening 83 and is blocked by the limit ring 82. Under the limiting effect of the limit ring 82, the positions of the pull rod 71 and the sliding plug 72 will be fixed. When sampling, the staff connects the air pipe 5 to the sampling port on the natural gas pipeline and opens the valve 6 to allow the natural gas to automatically enter the gas storage tank 3 under the action of the air pressure. After the sampling process continues for a period of time, the staff closes the valve 6 to complete the sampling of the natural gas. The LNG low temperature sampling and analysis device also includes a clamping structure, which is arranged on the gas analyzer 1 and is arranged opposite to the gas inlet 2. The clamping structure includes: two fixing rods 111, both fixed on the gas analyzer 1; a mounting ring 112, fixed to one end of the two fixing rods 111 away from the gas analyzer 1, and the mounting ring 112 is arranged opposite to the gas inlet 2; a rotating ring 113, which is rotatably mounted on the mounting ring 112; a plurality of clamping sheets 114, all arranged between the mounting ring 112 and the rotating ring 113, and the plurality of clamping sheets 114 are circumferentially arranged. Array distribution; a plurality of sliders 115 are respectively fixed on the sides of a plurality of pressing pieces 114; a plurality of slideways 116 are all provided on the rotating ring 113, and the plurality of slideways 116 are distributed in a circumferential array, and a plurality of sliders 115 are respectively slidably arranged in the plurality of slideways 116; a plurality of guide blocks 117 are respectively fixed on the sides of the plurality of pressing pieces 114; a guide groove 118 is provided on the side of the mounting ring 112, and the cross section of the guide groove 118 is a regular hexagonal structure, and each guide block 117 is slidably arranged in the guide groove 118; The LNG low-temperature sampling and analysis device also includes a damping structure, which is arranged on the gas analyzer 1, and the damping structure includes: a side plate 121, which is fixed to the side of the gas analyzer 1; an outer cylinder 122, which is fixed to the bottom surface of the side plate 121, and the opening of the outer cylinder 122 faces downward; a clamping rod 123, which is slidably arranged in the outer cylinder 122, and the bottom end of the clamping rod 123 extends to the outside of the outer cylinder 122, and the clamping rod 123 is arranged opposite to the rotating ring 113, and the outer surface of the clamping rod 123 and the inner surface of the outer cylinder 122 are in contact with each other; a spring 124, one end of which is connected to the inner top surface of the outer cylinder 122, and the other end is connected to the clamping rod 123. For the clamping structure, when the gas storage tank 3 is inserted into the rotating ring 113, the staff rotates the rotating ring 113. When the rotating ring 113 rotates, the plurality of slideways 116 will squeeze the plurality of sliders 115, and between the plurality of guide blocks 117 and the guide grooves Under the guiding action of 118, the plurality of pressing pieces 114 can move synchronously and perform opening and closing actions. When the plurality of pressing pieces 114 perform closing actions, the plurality of pressing pieces 114 can clamp the gas tank 3 together, thereby fixing the gas tank 3. The design of the clamping structure can ensure the stability of the gas tank 3 during the gas delivery process and avoid the gas tank 3 and the gas analyzer 1 from falling off. In addition, under the elastic force of the second spring 124, the pressing rod 123 always has a tendency to move downward. During the rotation of the rotating ring 113, the pressing rod 123 can always press the rotating ring 113. This design can prevent the rotating ring 113 from rotating under non-human circumstances. When the rotating ring 113 is fixed, the plurality of pressing pieces 114 will also be fixed. By setting the pressing rod 123, the pressing effect of the plurality of pressing pieces 114 on the gas tank 3 can be ensured. A clamping structure and a control structure are provided below the bracket 4, and the clamping structure includes: a plurality of connecting rods 91, all fixed on the limiting ring 82; a fixing ring 92, fixed on one end of the plurality of connecting rods 91 away from the limiting ring 82; a plurality of sliding openings 93, all opened on the outer peripheral surface of the fixing ring 92; a plurality of pressing plates 94, respectively slidably arranged in the plurality of sliding openings 93, each pressing plate 94 is provided with an inclined surface, and the control structure includes: two connecting rods 3 101, all fixed on the limiting ring 82; a threaded cylinder 102, fixed on one end of the two connecting rods 3 101 away from the limiting ring 82, and the outer peripheral surface of the threaded cylinder 102 is provided with a thread; a lifting sleeve 103, which is threadedly sleeved on the threaded cylinder 102; a lifting cover 104, fixed on the top of the lifting sleeve 103, and the lifting cover 104 is located below the plurality of pressing plates 94, The top opening of the lifting cover 104 is larger than the bottom opening. When the lifting sleeve 103 moves, it can drive the lifting cover 104 to move. During the movement, the lifting cover 104 will squeeze the inclined surfaces of several pressure plates 94. Since the top opening of the lifting cover 104 is larger than the bottom opening, the inclined surfaces of several pressure plates 94 can move synchronously when squeezed by the lifting cover 104 and approach the pull rod 71 until several pressure plates 94 press the pull rod 71 together. At this time, several pressure plates 94 can apply a certain pressure to the pull rod 71, which can slow down the movement speed of the pull rod 71, and the movement speed of the sliding plug 72 is also reduced accordingly. This design can prevent the sliding plug 72 from moving too fast under the elastic force of the spring 73, so that the gas can slowly enter the interior of the gas analyzer 1, and avoid the natural gas sampling speed being too fast.

[0020] The specific working principle of the present invention is as follows: When the LNG low-temperature sampling and analysis device proposed by the present invention is used, the staff first uses the gas storage tank 3 to sample the natural gas. The gas storage tank 3 is connected to the gas pipe 5, and the gas pipe 5 is installed with a valve 6. Before sampling, the staff first pulls the pull rod 71 to drive the sliding plug 72 to move. In the process of pulling the pull rod 71, the staff needs to align the limit block 84 with the limit opening 83 and make the limit block 84 pass through the limit opening 83. When the limit block 84 passes through the limit opening 83, the staff rotates the pull rod 71 to align the limit block 84 with the limit opening 83. The block 84 rotates accordingly until the limit block 84 and the limit opening 83 are offset from each other. At this time, the limit block 84 cannot pass through the limit opening 83 and is blocked by the limit ring 82. Under the limiting effect of the limit ring 82, the positions of the pull rod 71 and the sliding plug 72 will be fixed. When sampling, the staff connects the air pipe 5 to the sampling port on the natural gas pipeline and opens the valve 6, so that the natural gas automatically enters the gas storage tank 3 under the action of the air pressure. After the sampling process continues for a period of time, the staff closes the valve 6 to complete the sampling of the natural gas. When testing natural gas, the staff inserts the gas storage tank 3 into the rotating ring 113 and the mounting ring 112, aligning the gas pipe 5 with the gas inlet 2 on the gas analyzer 1. The gas inlet 2 is provided with a gas nozzle adapted to the gas pipe 5 to facilitate the connection between the gas pipe 5 and the gas inlet 2. Then, the staff rotates the pull rod 71 to drive the limit block 84 to rotate until the limit block 84 rotates to a position facing the limit opening 83, so that the limit block 84 can pass through the limit opening 83. In this case, the staff opens the valve 6 to allow the natural gas to be ejected through the gas pipe 5 and enter. In the process of discharging natural gas, the sliding plug 72 will move under the elastic force of the spring 73 and push the natural gas in the gas storage tank 3 to realize automatic natural gas sample delivery. Since the limit block 84 is already facing the limit opening 83, the limit ring 82 no longer blocks the limit block 84, and the sliding plug 72 and the pull rod 71 can move smoothly. This sample delivery method does not require the use of an air pump to extract the natural gas in the gas storage tank 3. On the one hand, it can reduce the overall cost of the gas analyzer 1, and on the other hand, it can reduce the adverse effects of the operation of the air pump on the gas analyzer 1. Before delivering the natural gas sample, the staff can rotate the lifting sleeve 103 to move the lifting sleeve 103 on the threaded cylinder 102. When the lifting sleeve 103 moves, it can drive the lifting cover 104 to move. The lifting cover 104 will squeeze the inclined surfaces of the plurality of pressure plates 94 during the movement. Since the top opening of the lifting cover 104 is larger than the bottom opening, the inclined surfaces of the plurality of pressure plates 94 can move synchronously when squeezed by the lifting cover 104 and approach the pull rod 71 until the plurality of pressure plates 94 jointly press the pull rod 71. At this time, the plurality of pressure plates 94 can apply a certain pressure to the pull rod 71, and the pressure can slow down the moving speed of the pull rod 71, and the moving speed of the sliding plug 72 is also reduced accordingly. This design can prevent the sliding plug 72 from moving too fast under the elastic force of the spring 73, so that the gas can slowly enter the interior of the gas analyzer 1, and prevent the natural gas from being delivered too fast. The gas analyzer 1 is also provided with a clamping structure for fixing the gas tank 3. For the clamping structure, when the gas tank 3 is inserted into the rotating ring 113, the staff rotates the rotating ring 113. When the rotating ring 113 rotates, the plurality of slideways 116 squeeze the plurality of sliders 115. Under the guidance of the plurality of guide blocks 117 and the guide grooves 118, the plurality of clamping sheets 114 can move synchronously and perform an opening and closing action. When the plurality of clamping sheets 114 perform a closing action, the plurality of clamping sheets 114 can clamp the gas tank 3 together, thereby fixing the gas tank 3. The design of the clamping structure It can ensure the stability of the gas tank 3 during the gas delivery process and avoid the phenomenon of falling off between the gas tank 3 and the gas analyzer 1. In addition, under the elastic force of the spring 124, the clamping rod 123 always has a tendency to move downward. When the rotating ring 113 rotates, the clamping rod 123 can always press the rotating ring 113. This design can avoid the rotating ring 113 from rotating under non-human circumstances. When the rotating ring 113 is fixed, several clamping plates 114 will also be fixed. By setting the clamping rod 123, the clamping effect of several clamping plates 114 on the gas tank 3 can be guaranteed.

[0021] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An LNG cryogenic sampling and analysis device, characterized in that: include: Gas analyzer (1); An air inlet (2) is provided on the gas analyzer (1); A gas storage tank (3) is mounted on the gas analyzer (1) and is arranged directly opposite to the gas inlet (2); A bracket (4) is fixed on the gas storage tank (3), and a through opening is formed on the bracket (4); An air pipe (5) is fixed to the top of the air storage tank (3) and is connected to the interior of the air storage tank (3); A valve (6) mounted on the air pipe (5); An air supply structure, arranged inside the air storage tank (3); A limiting structure, arranged on the bracket (4); A clamping structure, arranged on the gas analyzer (1) and facing the gas inlet (2); A damping structure, arranged on the gas analyzer (1); The damping structure comprises: A side plate (121) fixed on a side of the gas analyzer (1); An outer cylinder (122) is fixed to the bottom surface of the side plate (121), and the opening of the outer cylinder (122) faces downward; A pressing rod (123) is slidably disposed in the outer cylinder (122), the bottom end of the pressing rod (123) extends to the outside of the outer cylinder (122), and the pressing rod (123) is disposed opposite to the rotating ring (113); Spring 2 (124) has one end connected to the inner top surface of the outer cylinder (122) and the other end connected to the pressing rod (123).

2. The LNG cryogenic sampling and analysis device according to claim 1, characterized in that: The air supply structure comprises: A pull rod (71) passes through the bottom surface of the gas storage tank (3) and is slidably connected to the gas storage tank (3); one end of the pull rod (71) located outside the gas storage tank (3) passes through a hole on the bracket (4); A sliding plug (72) is sealingly and slidably connected inside the gas storage tank (3), and one end of the pull rod (71) located inside the gas storage tank (3) is rotatably connected to the sliding plug (72); Spring 1 (73) has one end connected to the inner wall of the gas storage tank (3) and the other end connected to the sliding plug (72).

3. The LNG cryogenic sampling and analysis device according to claim 2, characterized in that: The limiting structure comprises: A plurality of connecting rods (81), all fixed on the bracket (4); A limiting ring (82) is fixed to one end of one of the plurality of connecting rods (81) away from the bracket (4); A limiting opening (83) is provided on the inner ring of the limiting ring (82); A limit block (84) is fixed to one end of the pull rod (71) located outside the gas storage tank (3).

4. The LNG cryogenic sampling and analysis device according to claim 1, characterized in that: The clamping structure comprises: Two fixing rods (111), both fixed on the gas analyzer (1); A mounting ring (112) fixed to one end of the two fixing rods (111) away from the gas analyzer (1), the mounting ring (112) being arranged directly opposite to the gas inlet (2); A rotating ring (113) rotatably mounted on the mounting ring (112); A plurality of compression plates (114), each disposed between the mounting ring (112) and the rotating ring (113), wherein the plurality of compression plates (114) are distributed in a circumferential array; A plurality of sliding blocks (115) are respectively fixed on the side surfaces of the plurality of pressing plates (114); A plurality of slideways (116) are all provided on the rotating ring (113), the plurality of slideways (116) are distributed in a circumferential array, and the plurality of sliders (115) are respectively slidably disposed in the plurality of slideways (116); A plurality of guide blocks (117) are respectively fixed on the side surfaces of the plurality of pressing sheets (114); A guide groove (118) is provided on a side surface of the mounting ring (112); a cross section of the guide groove (118) is a regular hexagonal structure; and each guide block (117) is slidably disposed in the guide groove (118).

5. The LNG cryogenic sampling and analysis device according to claim 3, characterized in that: A clamping structure and a control structure are provided below the support (4), and the clamping structure comprises: A plurality of connecting rods (91) are fixed on the limiting ring (82); A fixing ring (92) fixed to one end of the plurality of connecting rods (91) away from the limiting ring (82); A plurality of sliding openings (93) are provided on the outer peripheral surface of the fixing ring (92); A plurality of pressing plates (94) are slidably disposed in the plurality of sliding openings (93), and each pressing plate (94) is provided with an inclined surface.

6. The LNG cryogenic sampling and analysis device according to claim 5, characterized in that: The control structure includes: Two connecting rods (101) are both fixed on the limiting ring (82); A threaded barrel (102) is fixed to one end of the two connecting rods (101) away from the limiting ring (82), and the outer peripheral surface of the threaded barrel (102) is provided with threads; A lifting sleeve (103) threadedly sleeved on the threaded cylinder (102); A lifting cover (104) is fixed on the top end of the lifting sleeve (103), and the lifting cover (104) is located below a plurality of pressure plates (94).

7. The LNG cryogenic sampling and analysis device according to claim 6, characterized in that: The top opening of the lifting cover (104) is larger than the bottom opening.

8. The LNG cryogenic sampling and analysis device according to claim 2, characterized in that: A pull ring is fixed to one end of the pull rod (71) away from the sliding plug (72).

9. The LNG cryogenic sampling and analysis device according to claim 1, characterized in that: The outer surface of the pressing rod (123) and the inner surface of the outer cylinder (122) are in contact with each other.

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