Online LNG (Liquefied Natural Gas) sampler and sampling method thereof

Abstract

The invention relates to the technical field of LNG sampling, and discloses an online LNG sampler and a sampling method thereof.The online LNG sampler comprises a sampling unit, a cold insulation unit, a water storage unit and a sealing unit; wherein the sampling unit comprises a machine shell, a sample storage steel cylinder and a pipeline, the sample storage steel cylinder is arranged in the machine shell, mounting pipes are fixed to the two ends of the sample storage steel cylinder, lantern rings are fixedly arranged on the two mounting pipes in a sleeving mode, and the pipeline is arranged in the machine shell. By adopting a dynamic cold insulation mode and combining liquid cooling and air cooling technologies, temperature fluctuation in the cold insulation box can be reduced to the maximum extent, a stable low-temperature state can be maintained, the gasification phenomenon of sample LNG in the flowing process in a pipeline is effectively avoided, the detection precision of the sample LNG is ensured, and the detection accuracy of the sample LNG is improved. The efficient cold insulation performance provides a reliable data basis for subsequent sample analysis.

Description

Technical Field

[0001] The invention relates to the technical field of LNG sampling, in particular to an online LNG sampler and a sampling method thereof. Background Art

[0002] Online LNG sampler is a device used to obtain liquefied natural gas (LNG) samples for quality and composition analysis. Online LNG sampler safely obtains representative liquefied gas samples through a closed sampling system without changing the sample composition and pressure. This usually involves the use of specialized valves and pipeline systems, as well as insulation and pressure control technology to ensure that the sample maintains its original state during the collection process.

[0003] After searching, the Chinese patent with publication number CN114878258A discloses a precise and controllable LNG sampling and gasification device, comprising: a sampling inner tube, the inlet end of which is connected to the LNG sampling main pipe, and the sampling inner tube is configured to extract the cryogenic sample LNG in the LNG sampling main pipe; a gasification mechanism, which is connected to the outlet end of the sampling inner tube, and the gasification mechanism is configured to gasify the cryogenic sample LNG transported by the sampling inner tube; a flow control mechanism, which is arranged on the sampling inner tube located upstream of the gasification mechanism, and the flow control mechanism is configured to control the flow of the cryogenic sample LNG transported by the sampling inner tube and to protect the integrity of the gasified natural gas sample. The above scheme can not only obtain the sample LNG with integrity, but also gasify it into a representative gaseous natural gas sample. However, the above scheme still has the following shortcomings when it is actually used: The above scheme adopts a static cooling method to keep LNG cold. The static cooling mode usually relies on thermal insulation materials and insulation design to maintain the supercooled state of the sample LNG, but this method often has limited cooling effect in practical applications. Due to the low temperature and high pressure characteristics of LNG, even with cooling measures, it is still difficult to completely avoid the fractionation and gasification of the sample during the sampling process. Once a component begins to vaporize, the proportion of each component in the sample will change, resulting in deviations between the samples entering the online analysis system and the sample collection system and the actual samples. This deviation will affect the accuracy of the test results.

[0004] Therefore, it is necessary to design an online LNG sampler and a sampling method thereof 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 online LNG sampler and a sampling method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: Online LNG sampler, including sampling unit, cold preservation unit, water storage unit and sealing unit; The sampling unit comprises a casing, a sample storage cylinder and a pipeline. The sample storage cylinder is arranged inside the casing. Both ends of the sample storage cylinder are fixed with mounting tubes. Rings are fixedly sleeved on the two mounting tubes. The pipeline is arranged inside the casing. The cold preservation unit is arranged inside the casing, and the cold preservation unit is composed of a cold preservation box, a refrigeration component and a refrigeration compressor. The cold preservation box is arranged inside the casing, the pipeline is assembled inside the cold preservation box, the refrigeration component is arranged inside the cold preservation box, and the refrigeration compressor is installed inside the casing; Wherein, the water storage unit is composed of a water storage component and a wiper component; Wherein, the sealing unit is composed of two sealing components, a driving component and two air supply components. The two sealing components are respectively arranged opposite to two mounting tubes. The driving component is used to drive the two sealing components to move, and the two air supply components are used to supply air into the two sealing components.

[0007] As a preferred technical solution of the present invention, the refrigeration assembly includes an outer tube, an inner tube, a refrigerant storage box, a water pump and an air pump. The outer tube is fixed inside the cold-keeping box, the inner tube is fixed inside the outer tube, the bottom end of the inner tube extends to the outside of the outer tube, and is provided with an exhaust port. A liquid flow area is formed between the outer tube and the inner tube, the refrigerant storage box is fixed inside the casing, the water pump and the air pump are both installed on the side of the refrigerant storage box, the input end of the water pump is connected to the refrigerant storage box, and the output end is connected to the outer tube, the air outlet end of the air pump is connected to the inner tube, the outer tube is connected to the input end of the refrigeration compressor, and the refrigerant storage box is connected to the output end of the refrigeration compressor.

[0008] As a preferred technical solution of the present invention, the outer tube and the inner tube are both in a spiral structure, and the outer tube and the inner tube are both made of pure copper material.

[0009] As a preferred technical solution of the present invention, the water storage assembly includes a water storage seat, a fixed block, a drain pipe and a water receiving tank. The water storage seat is fixed inside the casing, one end of the fixed block is connected to the water storage seat, and the other end is connected to the cold-keeping box, the water storage seat is located directly below the cold-keeping box, the water receiving tank is installed on the side of the casing, one end of the drain pipe is connected to the water storage seat, and the other end is connected to the water receiving tank.

[0010] As a preferred technical solution of the present invention, the wiper assembly includes a cylinder, a movable frame and a connecting block, the cylinder is installed inside the casing, the movable frame is slidably sleeved on the cold-keeping box, a plurality of wiper strips are fixed to the inner ring of the movable frame, each of the wiper strips is in contact with the surface of the cold-keeping box, the connecting block is fixed to the side of the movable frame, and the telescopic end of the cylinder is fixedly connected to the connecting block.

[0011] As a preferred technical solution of the present invention, the sealing assembly includes a connecting tube, a telescopic tube, a sealing tube, a sealing bag, a first sealing ring and a second sealing ring. The connecting tube is fixed inside the casing, one end of the telescopic tube is connected to the connecting tube, and the other end is connected to the sealing tube. The sealing tube is arranged opposite to the mounting tube, the sealing bag is fixed inside the sealing tube, the sealing bag has a cylindrical structure, the first sealing ring is fixed at one end of the sealing tube away from the telescopic tube, and the second sealing ring is fixed on the ring.

[0012] As a preferred technical solution of the present invention, the driving assembly includes a mounting frame, a dual-axis motor, two screw rods, two movable seats and two fixed plates. The mounting frame is fixed inside the casing, the dual-axis motor is assembled in the middle position of the mounting frame, the two screw rods are respectively fixed on the two output shafts of the dual-axis motor, the two movable seats are respectively threaded on the two screw rods, the two movable seats are both slidably assembled on the mounting frame, the two fixed plates are respectively fixedly connected to the two sealing tubes, the two fixed plates are respectively arranged on the sides of the two movable seats, and the fixed plates are connected to the movable seats through a connecting assembly.

[0013] As a preferred technical solution of the present invention, the connecting assembly includes a connecting plate, a slot and a slider, the connecting plate is fixed to the side of the movable seat, the slot is opened on the side of the connecting plate, the slider is slidably assembled in the slot, the slider and the slot are connected by a connecting spring, and the cross-sections of the slot and the slider are both T-shaped structures.

[0014] As a preferred technical solution of the present invention, the air supply assembly includes a sealing cylinder, a sliding plug and a connecting rod. The sealing cylinder is fixed on the mounting frame, and the sliding plug is sealingly slidably connected to the interior of the sealing cylinder. The sliding plug and the inner surface of the sealing cylinder are connected by a return spring. One end of the connecting rod is fixed on the sliding plug, and the other end extends to the outside of the sealing cylinder. The connecting rod is arranged opposite to the movable seat.

[0015] The sampling method of the online LNG sampler comprises the following steps: Step 1: The staff installs the sample cylinder into the housing, ensuring that the installation tube is facing the sealing tube; Step 2: Start the dual-axis motor to drive the screw to rotate, so that the moving seat drives the sealing tube sleeve to be installed on the installation tube, and realizes double sealing by connecting the spring and the sealing bag; Step 3: The sealing tube compresses the sleeve ring, and the first sealing ring and the second sealing ring are pressed against each other to ensure the sealing performance of the end position of the sample storage cylinder; Step 4: The sample LNG is introduced into the sample storage cylinder through the pipeline and is ready for storage; Step 5: The water pump and the air pump operate synchronously to extract the refrigerant and perform dynamic cold-keeping treatment combining liquid cooling and air cooling on the cold-keeping box and the pipeline through the outer tube and the inner tube; Step 6: The refrigerant circulates in the refrigerant storage box, the liquid flow area and the refrigeration compressor to ensure that the inside of the cold storage box is at a low temperature to prevent the sample LNG from gasifying; Step 7: The cylinder drives the moving frame and the wiper strip to scrape the water mist on the surface of the cold storage box in real time, so that the water mist gathers into water droplets and is introduced into the water storage seat to prevent condensed water from dripping and damaging electronic devices; Step 8. The NG samples are safely stored in the sample storage cylinder under cold conditions. The sampling process is completed and ready for subsequent testing and analysis.

[0016] The present invention has the following beneficial effects: 1. By adopting a dynamic cold preservation method and combining liquid cooling and air cooling technology, the present invention can minimize the temperature fluctuation inside the cold preservation box and maintain a stable low temperature state, which effectively avoids the gasification phenomenon of the sample LNG during the flow inside the pipeline, thereby ensuring the detection accuracy of the sample LNG. The efficient cold preservation performance provides a reliable data basis for subsequent sample analysis; 2. The designed water storage unit can scrape and collect condensed water on the surface of the cold storage box in real time to prevent the condensed water from dripping randomly and threatening the electronic devices and circuits inside the casing. This mechanism not only ensures the normal operation of the equipment, but also improves the safety and reliability of the equipment. At the same time, by scraping off the water mist in real time, it also improves the heat exchange efficiency of the cold storage box and optimizes the overall temperature control effect; 3. The sealing unit provided by the present invention realizes rapid and effective automatic sealing of the sample storage cylinder, replacing the traditional manual sealing method. This improvement not only simplifies the operating process and reduces the labor intensity of the staff, but also significantly improves the operating efficiency. The reliability of automatic sealing also ensures the sealing performance of the sample storage cylinder during the sampling process to prevent sample leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the online LNG sampler proposed by the present invention; Figure 2 This is a structural schematic diagram of the online LNG sampler proposed by the present invention from another perspective; Figure 3 It is a structural schematic diagram of the cold preservation unit; Figure 4 It is a structural schematic diagram of the sample storage cylinder and the sealing unit; Figure 5 It is a structural schematic diagram of the sample storage cylinder and the sealing unit from another perspective; Figure 6 It is a schematic diagram of the cross-sectional structure of the sample storage cylinder; Figure 7 This is an enlarged view of the local structure of the sample storage cylinder in a cutaway state; Figure 8 for Figure 3 A magnified view of the structure at A; Fig. 9 for Figure 4 A magnified view of the structure at B; Fig.10 for Figure 5 A magnified view of the structure at C; Fig.11 for Figure 6 A magnified view of the structure at D; Fig.12 for Figure 7 Enlarged view of the structure at E.

[0018] In the figure: 11, housing; 12, sample cylinder; 121, mounting pipe; 122, collar; 13, pipeline; 21, cold storage box; 22, outer tube; 23, inner tube; 24, exhaust port; 25, refrigerant storage box; 26, water pump; 27, air pump; 28, refrigeration compressor; 31, water storage seat; 32, fixing block; 33, drain pipe; 34, water receiving box; 35, cylinder; 36, moving frame; 37, wiper strip; 38 , connecting block; 41, connecting pipe; 42, telescopic pipe; 43, sealing pipe; 44, sealing bag; 45, first sealing ring; 46, second sealing ring; 51, mounting frame; 52, dual-axis motor; 53, screw rod; 54, moving seat; 55, connecting plate; 56, slotting; 57, sliding block; 58, connecting spring; 59, fixing plate; 61, sealing cylinder; 62, sliding plug; 63, connecting rod; 64, reset spring; 65, air supply pipe. DETAILED DESCRIPTION

[0019] 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.

[0020] Reference Figure 1-12The online LNG sampler includes a sampling unit, a cold preservation unit, a water storage unit and a sealing unit. The sampling unit includes a casing 11, a sample storage cylinder 12 and a pipeline 13. The sample storage cylinder 12 is arranged inside the casing 11. Both ends of the sample storage cylinder 12 are fixed with mounting pipes 121. Both mounting pipes 121 are fixedly sleeved with collars 122. The pipeline 13 is arranged inside the casing 11. The cold-keeping unit is arranged inside the casing 11, and the cold-keeping unit is composed of a cold-keeping box 21, a refrigeration component and a refrigeration compressor 28. The cold-keeping box 21 is arranged inside the casing 11, and the pipeline 13 is assembled inside the cold-keeping box 21. The refrigeration component is arranged inside the cold-keeping box 21, and the refrigeration compressor 28 is installed inside the casing 11. The refrigeration component includes an outer tube 22, an inner tube 23, a refrigerant storage box 25, a water pump 26 and an air pump 27. The outer tube 22 and the inner tube 23 are both spiral structures. The outer tube 22 and the inner tube 23 are both made of pure copper material. The outer tube 22 is fixed inside the cold-keeping box 21, and the inner tube 23 is fixed inside the outer tube 22. The bottom end of the inner tube 23 extends to the outside of the outer tube 22, and an exhaust port 24 is opened. A liquid flow area is formed between the outer tube 22 and the inner tube 23. The refrigerant storage box 25 is fixed inside the casing 11, and the water pump 26 and the air pump 27 are installed. Installed on the side of the refrigerant storage box 25, the input end of the water pump 26 is connected to the refrigerant storage box 25, and the output end is connected to the outer tube 22, the air outlet end of the air pump 27 is connected to the inner tube 23, the outer tube 22 is connected to the input end of the refrigeration compressor 28, the refrigerant storage box 25 is connected to the output end of the refrigeration compressor 28, the outer tube 22 and the inner tube 23 are both spiral structures, and the outer tube 22 is evenly distributed inside the cold-keeping box 21. This design can not only ensure the cooling effect of the outer tube 22 on the inside of the cold-keeping box 21, but also prolong the flow time of the gas in the inner tube 23, increase the heat exchange time between the gas and the refrigerant, thereby ensuring the cooling effect of the refrigerant on the gas. In addition, the outer tube 22 and the inner tube 23 are made of pure copper material with high thermal conductivity, in order to improve the heat exchange efficiency between the outer tube 22 and the inner tube 23 and reduce heat loss; The water storage unit is composed of a water storage component and a wiper component. The water storage component includes a water storage seat 31, a fixed block 32, a drain pipe 33 and a water receiving box 34. The water storage seat 31 is fixed inside the casing 11. One end of the fixed block 32 is connected to the water storage seat 31, and the other end is connected to the cold-keeping box 21. The water storage seat 31 is located directly below the cold-keeping box 21. The water receiving box 34 is installed on the side of the casing 11. One end of the drain pipe 33 is connected to the water storage seat 31, and the other end is connected to the water receiving box 34. The wiper component includes a cylinder 35, a moving frame 36 and a connecting block 38. The cylinder 35 is installed inside the casing 11. The moving frame 36 is slidably sleeved on the cold-keeping box 21. The inner circle of the moving frame 36 is fixed with a plurality of wiper strips 37, each of which is in contact with the surface of the cold-keeping box 21. The connecting block 38 is fixed to the moving frame 3 6, the telescopic end of the cylinder 35 is fixedly connected to the connecting block 38. When the cold preservation unit is in operation, the cylinder 35 is started and drives the moving frame 36 to move up and down. When the moving frame 36 moves, the multiple wiper strips 37 on the inner circle can contact the surface of the cold preservation box 21 and scrape the water mist on the surface of the cold preservation box 21, so that the water mist gathers into water droplets and falls into the water storage seat 31 under the push of the wiper strips 37. This mechanism not only effectively collects condensed water to prevent it from posing a threat to the electronic devices and circuits inside the housing 11, but more importantly, it significantly improves the heat exchange efficiency of the cold preservation box 21, ensuring that the surface of the cold preservation box 21 can continuously and efficiently transfer heat to the outside world, thereby maintaining a stable low temperature state of the cold preservation box 21 and optimizing the overall temperature control effect; The sealing unit is composed of two sealing components, a driving component and two air supply components. The two sealing components are respectively arranged opposite to the two mounting tubes 121. The driving component is used to drive the two sealing components to move. The two air supply components are used to supply air into the two sealing components. The sealing component includes a connecting tube 41, a telescopic tube 42, a sealing tube 43, a sealing capsule 44, a first sealing ring 45 and a second sealing ring 46. The connecting tube 41 is fixed inside the housing 11. One end of the telescopic tube 42 is connected to the connecting tube 41, and the other end is connected to the sealing tube 43. The sealing tube 43 is arranged opposite to the mounting tube 121. The sealing capsule 44 is fixed inside the sealing tube 43. The sealing capsule 44 is a cylindrical structure. The first sealing ring 45 is fixed to one end of the sealing tube 43 away from the telescopic tube 42. The second sealing ring 46 is fixed on the collar 122. When the sealing tube 43 presses the collar 122, the first sealing ring 45 and the second sealing ring 46 will be pressed against each other to improve the sealing performance between the sealing tube 43 and the collar 122. The driving assembly includes a mounting frame 51, a dual-axis motor 52, two screw rods 53, two moving seats 54 and two fixed plates 59. The mounting frame 51 is fixed inside the housing 11, the dual-axis motor 52 is assembled in the middle of the mounting frame 51, the two screw rods 53 are respectively fixed on the two output shafts of the dual-axis motor 52, the two moving seats 54 are respectively threadedly sleeved on the two screw rods 53, the two moving seats 54 are slidably assembled on the mounting frame 51, and the two fixed plates 59 are respectively fixed to the two sealing tubes 43. The two fixed plates 59 are arranged on the sides of the two moving seats 54 respectively. The fixed plate 59 and the moving seat 54 are connected by a connecting assembly. The connecting assembly includes a connecting plate 55, a slot 56 and a slider 57. The connecting plate 55 is fixed on the side of the moving seat 54. The slot 56 is provided on the side of the connecting plate 55. The slider 57 is slidably assembled in the slot 56. The slider 57 and the slot 56 are connected by a connecting spring 58. The cross-sections of the slot 56 and the slider 57 are both T-shaped structures. When the shaft motor 52 is running, it drives the two screw rods 53 to rotate, so that the two moving seats 54 move synchronously and approach each other. For the moving seat 54, when the moving seat 54 moves, it can drive the connecting plate 55 thereon to move. The connecting plate 55 drives the fixed plate 59 to move through the slider 57 and the connecting spring 58, and the sealing tube 43 connected to the fixed plate 59 moves accordingly. With the movement of the sealing tube 43, the sealing tube 43 will be sleeved on the mounting tube 121. When the sealing tube 43 presses the ring 122 on the mounting tube 121, the sealing tube 43 cannot continue to move, and the moving seat 54 will keep moving. In this case, relative movement will occur between the connecting plate 55 and the slider 57, so that the slider 57 squeezes the connecting spring 58. When the connecting spring 58 is compressed, the elastic force applied by the connecting spring 58 on the slider 57 can make the sealing tube 43 press the ring 122, thereby ensuring the sealing performance between the sealing tube 43 and the ring 122, and realizing automatic sealing of the end position of the sample storage cylinder 12. The air supply assembly includes a sealing cylinder 61, a sliding plug 62 and a connecting rod 63. The sealing cylinder 61 is fixed on the mounting frame 51. The sliding plug 62 is sealingly and slidably connected to the inside of the sealing cylinder 61. The sliding plug 62 is connected to the inner surface of the sealing cylinder 61 by a return spring 64. One end of the connecting rod 63 is fixed on the sliding plug 62, and the other end extends to the outside of the sealing cylinder 61. The connecting rod 63 is arranged opposite to the moving seat 54. When relative movement occurs between the connecting plate 55 and the slider 57, the connecting plate 55 will squeeze the connecting rod 63 at the same time, so that the connecting rod 63 moves downward. When the connecting rod 63 moves downward, the sliding plug 62 moves downward synchronously. In the process of moving downward, the sliding plug 62 can press the air inside the sealing cylinder 61 into the inside of the sealing bag 44 through the air supply pipe 65, so that the sealing bag 44 is inflated. When the sealing bag 44 expands, it will press the mounting tube 121 tightly, thereby ensuring the sealing performance between the sealing tube 43 and the mounting tube 121.

[0021] The specific working principle of the present invention is as follows: When the online LNG sampler proposed by the present invention is in use, the sample LNG enters the sample storage cylinder 12 through the pipeline 13 and is stored in the sample storage cylinder 12 to complete the LNG sampling. The present invention adopts a dynamic cold preservation method to perform cold preservation treatment on the sample LNG in the pipeline 13, which can effectively avoid the gasification of the sample LNG, thereby ensuring the detection accuracy of the sample LNG. Specifically, during the sampling process, the water pump 26 and the air pump 27 operate synchronously. When the water pump 26 operates, the refrigerant in the refrigerant storage box 25 is extracted and the refrigerant is pumped into the outer tube 22. The refrigerant flows into the liquid flow area between the inner tube 23, and then enters the refrigeration compressor 28, and finally flows back to the refrigerant storage box 25, so that the refrigerant circulates in the refrigerant storage box 25, the liquid flow area and the refrigeration compressor 28. In this process, the refrigerant liquid and the outer tube 22 can perform liquid cooling on the inside of the cold-keeping box 21 to ensure that the inside of the cold-keeping box 21 is in a low temperature state. When the refrigerant flows through the refrigeration compressor 28, the refrigeration compressor 28 can cool the refrigerant, so that the refrigerant flowing in the liquid flow area always has a sufficiently low temperature. The temperature is set to ensure the cooling effect of the refrigerant on the inside of the cold-keeping box 21. In addition, when the air pump 27 is running, it can extract the air inside the cold-keeping box 21 and pump the air 27 into the inner tube 23, so that the air flows inside the inner tube 23. One end of the inner tube 23 extends to the outside of the outer tube 22 and is provided with an exhaust port 24. The gas will eventually be re-discharged into the inside of the cold-keeping box 21 through the exhaust port 24. During the flow of the gas inside the inner tube 23, the refrigerant between the outer tube 22 and the inner tube 23 can cool the gas in the inner tube 23. Cooling makes the gas discharged through the exhaust port 24 have a lower temperature, so as to achieve air cooling of the inside of the cold preservation box 21. The low-temperature air will fill the inside of the cold preservation box 21 and fully contact with the pipeline 13, thereby further improving the cold preservation effect of the pipeline 13. Based on the above process, the present invention adopts a dynamic cold preservation method combining liquid cooling and air cooling, which can minimize the temperature fluctuation inside the cold preservation box 21, maintain the low temperature state inside the cold preservation box 21, and finally avoid the gasification phenomenon of the sample LNG in the process of flowing inside the pipeline 13; It should be noted that both the outer tube 22 and the inner tube 23 are spiral structures, and the outer tube 22 is evenly distributed inside the cold-keeping box 21. This design can not only ensure the cooling effect of the outer tube 22 on the inside of the cold-keeping box 21, but also prolong the flow time of the gas inside the inner tube 23, increase the heat exchange time between the gas and the refrigerant, thereby ensuring the cooling effect of the refrigerant on the gas. In addition, the outer tube 22 and the inner tube 23 are made of pure copper material with high thermal conductivity, in order to improve the heat exchange efficiency between the outer tube 22 and the inner tube 23 and reduce heat loss. The dynamic cold preservation method makes the surface temperature of the cold preservation box 21 very low. When the hot air in the casing 11 encounters the low-temperature cold preservation box 21, the gas is easily liquefied into liquid droplets on the surface of the cold preservation box 21, so that a layer of water mist is formed on the surface of the cold preservation box 21. Under the action of gravity, the tiny liquid droplets are easily gathered into droplets and slide down along the surface of the cold preservation box 21, and finally drip into the inside of the casing 11. The randomly dripping condensed water will threaten the electronic devices and circuits inside the casing 11. In order to avoid this phenomenon, the present invention is designed with a water storage unit The water storage unit is used to collect condensed water formed on the surface of the cold-keeping box 21. Specifically, when the cold-keeping unit is in operation, the cylinder 35 is started and drives the moving frame 36 to move up and down. When the moving frame 36 moves, the multiple wiper strips 37 on the inner circle of the moving frame 36 can contact the surface of the cold-keeping box 21 and scrape the water mist on the surface of the cold-keeping box 21, so that the water mist gathers into water droplets and falls into the water storage seat 31 under the push of the wiper strips 37. During the dynamic cold-keeping process, if the surface of the cold-keeping box 21 is continuously covered with water mist, it will hinder the cold-keeping. The heat exchange efficiency between the cold box 21 and the external environment is reduced. As a poor thermal conductor, water mist will increase the resistance of heat transfer, making it difficult for the cold box 21 to effectively dissipate heat, thereby affecting its cold-keeping performance. The water storage unit designed by the present invention drives the moving frame 36 and the wiper strip 37 installed thereon through the cylinder 35, which can scrape the water mist on the surface of the cold box 21 in real time, prompting the water mist to quickly gather into water droplets and be introduced into the water storage seat 31. This mechanism not only effectively collects condensed water, but also prevents it from posing a threat to the electronic devices and circuits inside the housing 11. More importantly, it significantly improves the heat exchange efficiency of the cold storage box 21, ensures that the surface of the cold storage box 21 can continuously and efficiently transfer heat to the outside world, thereby maintaining a stable low temperature state of the cold storage box 21 and optimizing the overall temperature control effect. In addition, a drain pipe 33 is connected to the water storage seat 31, and the drain pipe 33 is connected to an external water receiving box 34. When the water accumulated in the water storage seat 31 exceeds the drain pipe 33, the water will flow into the water receiving box 34 through the drain pipe 33 to prevent the water in the water storage seat 31 from overflowing; The present invention also provides a function of quickly sealing the sample storage cylinder 12, which is achieved through a sealing unit. The design of the sealing unit achieves a quick and effective sealing of the sample storage cylinder 12, replacing the traditional manual sealing method of the sample storage cylinder 12. In the prior art, the sample storage cylinder 12 is usually sealed by a locking nut, and the staff needs to use a wrench to tighten the locking nut to seal the sample storage cylinder 12. This method not only requires the use of tools, but also is cumbersome to operate and has low efficiency. The sealing unit proposed in the present invention can effectively solve this problem. Specifically, after the staff installs the sample storage cylinder 12 into the casing 11, the two installation tubes 121 at both ends of the sample storage cylinder 12 are just set opposite the two sealing tubes 43 respectively. At this time, the staff can start the dual-axis motor 52. When the dual-axis motor 52 is running, it drives the two screws 53 to rotate, so that the two moving seats 54 move synchronously and approach each other. For the moving seat 54, when the moving seat 54 moves, it can drive the connecting plate 55 thereon to move. The connecting plate 55 drives the fixed plate 59 to move through the slider 57 and the connecting spring 58, and the sealing tube 43 connected to the fixed plate 59 moves accordingly, accompanied by the sealing When the tube 43 moves, the sealing tube 43 will be sleeved on the installation tube 121. When the sealing tube 43 presses the collar 122 on the installation tube 121, the sealing tube 43 cannot continue to move, while the moving seat 54 will keep moving. In this case, the connecting plate 55 and the slider 57 will move relative to each other, so that the slider 57 squeezes the connecting spring 58. When the connecting spring 58 is compressed, the elastic force applied by the connecting spring 58 on the slider 57 can make the sealing tube 43 press the collar 122, thereby ensuring the sealing performance between the sealing tube 43 and the collar 122, and realizing the automatic sealing of the end position of the sample storage cylinder 12. When relative movement occurs between the connecting plate 55 and the slider 57, the connecting plate 55 will squeeze the connecting rod 63 at the same time, so that the connecting rod 63 moves downward. When the connecting rod 63 moves downward, the sliding plug 62 moves downward synchronously. In the process of moving downward, the sliding plug 62 can press the air inside the sealing tube 61 into the interior of the sealing bag 44 through the air supply pipe 65, so that the sealing bag 44 is inflated. When the sealing bag 44 expands, it will press the mounting tube 121, thereby ensuring the sealing performance between the sealing tube 43 and the mounting tube 121. In addition, a first sealing ring 45 is provided at the end of the sealing tube 43, and a second sealing ring 46 is provided on the ring 122. When the sealing tube 43 presses the ring 122, the first sealing ring 45 will be pressed against the second sealing ring 46 to improve the sealing performance between the sealing tube 43 and the ring 122. This automatic sealing method not only realizes effective sealing of the end position of the sample storage cylinder 12, but also can automatically seal the sample storage cylinder 12 without the need for manual operation with the aid of tools.

[0022] 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. Online LNG sampler, characterized in that: It includes a sampling unit, a cold preservation unit, a water storage unit and a sealing unit; The sampling unit comprises a casing (11), a sample storage cylinder (12) and a pipeline (13); the sample storage cylinder (12) is arranged inside the casing (11); mounting tubes (121) are fixed at both ends of the sample storage cylinder (12); collars (122) are fixedly sleeved on the two mounting tubes (121); and the pipeline (13) is arranged inside the casing (11); The cold preservation unit is arranged inside the casing (11); the cold preservation unit is composed of a cold preservation box (21), a refrigeration component and a refrigeration compressor (28); the cold preservation box (21) is arranged inside the casing (11); the pipeline (13) is installed inside the cold preservation box (21); the refrigeration component is arranged inside the cold preservation box (21); and the refrigeration compressor (28) is installed inside the casing (11); Wherein, the water storage unit is composed of a water storage component and a wiper component; The sealing unit is composed of two sealing components, a driving component and two air supply components. The two sealing components are respectively arranged opposite to two mounting tubes (121). The driving component is used to drive the two sealing components to move. The two air supply components are used to supply air into the two sealing components.

2. The online LNG sampler according to claim 1, characterized in that: The refrigeration assembly comprises an outer tube (22), an inner tube (23), a refrigerant storage box (25), a water pump (26) and an air pump (27); the outer tube (22) is fixed inside the cold-keeping box (21); the inner tube (23) is fixed inside the outer tube (22); the bottom end of the inner tube (23) extends to the outside of the outer tube (22) and is provided with an exhaust port (24); a liquid flow area is formed between the outer tube (22) and the inner tube (23); the refrigerant storage box (25) is provided with a refrigerant storage box (26); and the refrigerant storage box (25) is provided with a refrigerant storage box (27). The water pump (26) and the air pump (27) are fixed inside the casing (11), and are both installed on the side of the refrigerant storage box (25). The input end of the water pump (26) is connected to the refrigerant storage box (25), and the output end is connected to the outer tube (22). The air outlet end of the air pump (27) is connected to the inner tube (23), the outer tube (22) is connected to the input end of the refrigeration compressor (28), and the refrigerant storage box (25) is connected to the output end of the refrigeration compressor (28).

3. The online LNG sampler according to claim 2, characterized in that: The outer tube (22) and the inner tube (23) both have a spiral structure, and the outer tube (22) and the inner tube (23) are both made of pure copper material.

4. The online LNG sampler according to claim 1, characterized in that: The water storage assembly comprises a water storage seat (31), a fixing block (32), a drainage pipe (33) and a water receiving box (34); the water storage seat (31) is fixed inside the casing (11); one end of the fixing block (32) is connected to the water storage seat (31), and the other end is connected to the cold-keeping box (21); the water storage seat (31) is located directly below the cold-keeping box (21); the water receiving box (34) is installed on the side of the casing (11); one end of the drainage pipe (33) is connected to the water storage seat (31), and the other end is connected to the water receiving box (34).

5. The online LNG sampler according to claim 4, characterized in that: The wiper assembly comprises a cylinder (35), a movable frame (36) and a connecting block (38); the cylinder (35) is mounted inside the housing (11); the movable frame (36) is slidably sleeved on the cold-keeping box (21); a plurality of wiper strips (37) are fixed to the inner ring of the movable frame (36); each of the wiper strips (37) is in contact with the surface of the cold-keeping box (21); the connecting block (38) is fixed to the side of the movable frame (36); and the telescopic end of the cylinder (35) is fixedly connected to the connecting block (38).

6. The online LNG sampler according to claim 1, characterized in that: The sealing assembly comprises a connecting tube (41), a telescopic tube (42), a sealing tube (43), a sealing capsule (44), a first sealing ring (45) and a second sealing ring (46); the connecting tube (41) is fixed inside the housing (11); one end of the telescopic tube (42) is connected to the connecting tube (41) and the other end is connected to the sealing tube (43); the sealing tube (43) is arranged opposite to the mounting tube (121); the sealing capsule (44) is fixed inside the sealing tube (43); the sealing capsule (44) is in a cylindrical structure; the first sealing ring (45) is fixed to one end of the sealing tube (43) away from the telescopic tube (42); and the second sealing ring (46) is fixed to the collar (122).

7. The online LNG sampler according to claim 1, characterized in that: The driving assembly comprises a mounting frame (51), a double-axis motor (52), two screw rods (53), two moving seats (54) and two fixed plates (59); the mounting frame (51) is fixed inside the housing (11); the double-axis motor (52) is mounted at the middle of the mounting frame (51); the two screw rods (53) are respectively fixed on two output shafts of the double-axis motor (52); the two moving seats (54) are respectively threadedly sleeved on the two screw rods (53); the two moving seats (54) are both slidably mounted on the mounting frame (51); the two fixed plates (59) are respectively fixedly connected to the two sealing tubes (43); the two fixed plates (59) are respectively arranged on the sides of the two moving seats (54); and the fixed plates (59) and the moving seats (54) are connected via a connecting assembly.

8. The online LNG sampler according to claim 7, characterized in that: The connecting assembly comprises a connecting plate (55), a slot (56) and a slider (57); the connecting plate (55) is fixed to a side surface of the movable seat (54); the slot (56) is formed on a side surface of the connecting plate (55); the slider (57) is slidably assembled in the slot (56); the slider (57) and the slot (56) are connected via a connecting spring (58); and the cross-sections of the slot (56) and the slider (57) are both T-shaped structures.

9. The online LNG sampler according to claim 8, characterized in that: The air supply assembly comprises a sealing cylinder (61), a sliding plug (62) and a connecting rod (63); the sealing cylinder (61) is fixed on the mounting frame (51); the sliding plug (62) is sealingly slidably connected to the inside of the sealing cylinder (61); the sliding plug (62) and the inner surface of the sealing cylinder (61) are connected via a return spring (64); one end of the connecting rod (63) is fixed on the sliding plug (62) and the other end extends to the outside of the sealing cylinder (61); the connecting rod (63) is arranged opposite to the movable seat (54).

10. A sampling method of an online LNG sampler, based on the online LNG sampler according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: The staff installs the sample storage cylinder (12) into the housing (11), ensuring that the installation tube (121) is directly opposite to the sealing tube (43); Step 2: Start the dual-axis motor (52) to drive the screw (53) to rotate, so that the movable seat (54) drives the sealing tube (43) to be sleeved on the mounting tube (121), and realize double sealing by connecting the spring (58) and the sealing bag (44); Step 3: The sealing tube (43) presses the collar (122), and the first sealing ring (45) and the second sealing ring (46) are pressed against each other to ensure the sealing performance of the end position of the sample storage cylinder (12); Step 4: The sample LNG is introduced into the sample storage cylinder (12) through the pipeline (13) to prepare for storage; Step 5: The water pump (26) and the air pump (27) are operated synchronously to extract the refrigerant and perform a dynamic cold-keeping treatment combining liquid cooling and air cooling on the cold-keeping box (21) and the pipeline (13) through the outer tube (22) and the inner tube (23); Step 6: The refrigerant circulates in the refrigerant storage box (25), the liquid flow area and the refrigeration compressor (28) to ensure that the interior of the cold storage box (21) is in a low temperature state to prevent the sample LNG from gasifying; Step 7: The cylinder (35) drives the moving frame (36) and the wiper strip (37) to scrape off the water mist on the surface of the cold storage box (21) in real time, causing the water mist to gather into water droplets and be introduced into the water storage seat (31), thereby preventing condensed water from dripping and damaging the electronic components; Step 8: The sample LNG is safely stored in the sample storage cylinder (12) in a cold state. The sampling process is completed and is ready for subsequent testing and analysis.

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