Ultra-low temperature LNG valve fault diagnosis device and diagnosis method

Abstract

This invention discloses a fault diagnosis device for cryogenic LNG valves, relating to the field of valve fault diagnosis technology. The invention includes a diagnostic box and a valve. A support frame is fixedly connected to the top of the diagnostic box, and an electric push rod is fixedly connected through the top of the support frame. A top plate is located below the electric push rod, and a rotating connector is fixedly connected to the top of the top plate. The rotating connector is connected to an external gas source through a first gas source pipe. A hollow disc is rotatably connected through the bottom of the top plate, and multiple nozzles for drying the valve are connected to the bottom of the hollow disc. This invention, through the cooperation of a first screw and a nut ring, not only drives two sealing cones to seal and clamp the valve during lifting and lowering, but also drives the nozzles to rotate for rapid drying of the valve. This makes it easy to install and remove. Furthermore, the top plate seals the diagnostic box, and the height of the sliding plate within the indicator rod allows for direct observation of leakage conditions.

Description

Technical Field

[0001] This invention belongs to the field of valve fault diagnosis technology, and in particular relates to fault diagnosis equipment and methods for cryogenic LNG valves. Background Technology

[0002] Cryogenic valves include cryogenic ball valves, cryogenic gate valves, cryogenic stop valves, cryogenic safety valves, cryogenic check valves, cryogenic butterfly valves, cryogenic needle valves, cryogenic throttle valves, cryogenic pressure reducing valves, etc. They are mainly used in ethylene, liquefied natural gas (LNG) plants, LPG and LNG storage tanks, receiving bases and satellite stations, air separation equipment, petrochemical tail gas separation equipment, cryogenic storage tanks and tank trucks for liquid oxygen, liquid nitrogen, liquid argon, and carbon dioxide, and pressure swing adsorption oxygen production equipment.

[0003] A search revealed that utility model CN206330710 discloses a testing bench for detecting the sealing performance and shell strength of a copper ball valve. The bench includes a lifting platform, a testing device mounted on the lifting platform, and a vertical drive component that moves the lifting platform up and down to enter and exit the water surface. This utility model provides a testing bench for detecting the sealing performance and shell strength of a copper ball valve by filling the sealed copper ball valve with pressurized air and placing the pressurized valve below the water surface.

[0004] The test bench also has the following disadvantages during use: When using it, the valve is immersed in water and then inflated with air. The situation of the bubbles around the valve is observed to determine the leakage. However, because there is dust on the valve, when the valve is immersed in water, the water becomes very turbid, and the leakage bubbles are not easy to observe. In addition, the water stains on the valve cannot dry quickly after the test, making it inconvenient to remove. Summary of the Invention

[0005] The purpose of this invention is to provide a fault diagnosis device and method for cryogenic LNG valves. Through the cooperation of the first screw and the nut ring, it can not only drive the two sealing cones to seal and clamp the valve during the lifting process, but also drive the nozzle to rotate to quickly dry the valve. This makes it easy to install and take out. Furthermore, the top plate seals the diagnostic box, and the height of the sliding plate inside the indicator rod can be observed to visually observe the leakage situation, thus solving the existing technical problems.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] The cryogenic LNG valve fault diagnosis equipment includes: a diagnostic box and a valve. A support frame is fixedly connected to the top of the diagnostic box. An electric push rod is fixedly connected through the top of the support frame. A top plate is provided below the electric push rod. A rotating connector is fixedly connected to the top of the top plate. The rotating connector is connected to an external gas source through a first gas source pipe. A hollow disc is rotatably connected through the bottom of the top plate. Multiple nozzles for drying the valve are connected to the bottom of the hollow disc to enable rapid drying of the valve surface.

[0008] The bottom of the top plate is fixedly connected to multiple support columns, and the bottom of the multiple support columns is fixedly connected to the same filter plate. The filter plate is located inside the diagnostic box, and the top of the filter plate is fixedly connected to a support plate. The top of the support plate is provided with a placement groove for placing a valve and for limiting the valve.

[0009] The top of the filter plate is provided with two clamping plates for holding the valve. A sealing cone for sealing the valve is fixedly connected to one side of each clamping plate. One of the sealing cones and one side of the clamping plate are fixedly connected to the same insertion tube. One end of the insertion tube is connected to an external air source through the top plate via a second air source tube for detecting valve leakage.

[0010] The transmission mechanism, located on top of the filter plate, is used to drive the two clamping plates to move closer together to seal and hold the valve, and to drive the nozzle to rotate to quickly dry the surface of the valve.

[0011] Optionally, the transmission mechanism includes a nut ring rotatably connected to the top of the filter plate, a second gear fixedly sleeved on the outer wall of the nut ring, a first rack and a second rack slidably connected to the top of the filter plate and meshing with the second gear, a connecting block fixedly connected to one end of each of the first rack and the second rack, the connecting block on the second rack being slidably connected through the first rack, a clamping plate being disposed on the connecting block, and a first screw threaded on the inner wall of the nut ring, the first screw being fixedly connected to the bottom inner wall of the diagnostic box. Rotating the second gear can drive the first rack and the second rack to move relative to each other, thereby driving the clamping plate to clamp the valve.

[0012] Optionally, a sliding rod is fixedly connected to the top of the connecting block, the clamping plate is slidably sleeved on the sliding rod, a second screw is threadedly connected to the top of the clamping plate, the bottom of the second screw is rotatably connected to the connecting block, and rotating the second screw can drive the clamping plate to rise and fall.

[0013] Optionally, a rotating tube is fixedly connected to the top of the nut ring, the top of the rotating tube is rotatably connected to the top plate, a first gear is fixedly sleeved on the outer wall of the rotating tube, and an external toothed ring that meshes with the first gear is fixedly sleeved on the outer wall of the hollow disc. Rotation of the nut ring can drive the hollow disc to rotate, thereby driving the nozzle to rotate.

[0014] Optionally, a base plate is fixedly connected to the bottom of the top plate, and a sealing ring that mates with the inner wall of the diagnostic box is fitted on the outer wall of the top plate. An indicator rod is fixedly connected through the top of the top plate, and a through hole is opened at the bottom of the indicator rod. A sliding plate is slidably provided on the inner wall of the indicator rod. The gas inside the plate can drive the sliding plate to rise and fall, allowing for direct observation of leaks.

[0015] Optionally, a piston sleeve is fixedly connected to the bottom inner wall of the diagnostic box, a piston rod is slidably provided on the inner wall of the piston sleeve, a connecting plate is fixedly connected to the top of the piston rod, the connecting plate is fixedly connected to the filter plate, multiple vent holes are opened on the outer wall of the piston sleeve, the same piston plate is slidably provided on the outer wall of the first screw and the piston sleeve and the inner wall of the diagnostic box, and multiple limiting blocks that abut against the piston plate are fixedly connected to the bottom inner wall of the diagnostic box. The downward movement of the filter plate can drive the piston plate to rise, so that water can submerge the valve.

[0016] Optionally, the outer wall of the first screw is provided with a spiral groove and a straight sliding groove, the spiral groove and the straight sliding groove are connected, and a sliding block is fixedly connected to the inner wall of the nut ring. The sliding block is located in the spiral groove, and the clamping block can be lowered after being clamped by the spiral groove and the straight sliding groove.

[0017] The fault diagnosis method for cryogenic LNG valves includes the following steps:

[0018] S1. First, add an appropriate amount of water to the diagnostic box and make the water level at the top of the piston plate. Place the valve in the placement slot on the support plate and start the electric push rod. The electric push rod drives the top plate to descend. The top plate drives the filter plate to descend through the support column. At the same time as it descends, the sliding block and spiral groove can drive the nut ring to rotate. The rotation of the nut ring can drive the second gear to rotate. The rotation of the second gear can drive the second rack and the first rack to move relative to each other, causing the two clamping plates to move closer to each other. When the center point of the sealing cone is lower than the center point of the valve, rotating the second screw can drive the clamping plate to move upward and drive the sealing cone to move upward until the sealing cone is coaxial with the center point of the valve. Continuing to move downward can drive the two sealing cones to clamp the valve, so that the valve is sealed and fixed.

[0019] S2. Then continue to move downwards to make the top plate touch the top of the diagnostic box, so that the diagnostic box is sealed. This causes the sliding block to slide in the straight slide groove, and the two sealing cones are limited. At the same time, the piston rod moves downwards in the piston sleeve rod. The gas in the piston sleeve rod enters between the piston plate and the diagnostic box, which can drive the piston plate to move upwards. This can drive the water on the piston plate to move upwards, so that the water submerges the valve.

[0020] S3. Then start the external air source of the second air source pipe. The air source delivers gas into the valve through the second air source pipe and the insertion pipe. When the valve leaks, the gas inside the diagnostic box will drive the sliding plate to move upward through the through hole, so that it can be seen directly. When the valve is well sealed, the sliding plate will not move upward.

[0021] S4. After the test is completed, start the electric push rod to reset, which will drive the filter plate to reset. At the same time, it will first drive the sliding block to slide upward in the straight sliding groove. When the sliding block moves into the spiral groove, it will drive the second gear to rotate and drive the two clamping plates to move away from each other. At the same time, start the air source on one side of the first air source pipe. When the second gear rotates, it can drive the rotating pipe to rotate. The rotating pipe can drive the outer gear ring to rotate through the first gear. The outer gear ring drives the hollow disc to rotate, which drives the nozzle to rotate. The nozzle rotates and sprays gas to wash away the water stains on the valve and make the valve surface dry quickly.

[0022] The embodiments of the present invention have the following beneficial effects:

[0023] The first screw and nut ring work together to not only drive the two sealing cones to seal and clamp the valve during the lifting process, but also drive the nozzle to rotate to quickly dry the valve, making it easy to install and take off. The top plate seals the diagnostic box, allowing the height of the sliding plate inside the indicator rod to be observed, enabling direct observation of the leakage situation.

[0024] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a support column structure according to an embodiment of the present invention;

[0028] Figure 3 for Figure 2 Another perspective structural diagram;

[0029] Figure 4 This is a cross-sectional view of a diagnostic box according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of a clamping mechanism according to an embodiment of the present invention;

[0031] Figure 6 A schematic diagram of a rod structure according to an embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the first screw structure according to an embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram of an external toothed ring structure according to an embodiment of the present invention.

[0034] In the diagram: 1. Diagnostic box; 2. Support frame; 3. Electric push rod; 4. Filter plate; 5. Support column; 6. Top plate; 7. Support plate; 8. Valve; 9. Clamping plate; 10. Sealing cone; 11. Schematic bar; 12. First air source pipe; 13. Rotary connector; 14. Second air source pipe; 15. Insertion tube; 16. Base plate; 17. Limiting block; 18. Hollow disc; 19. External toothed ring; 20. Nozzle; 21. Rotating tube; 22. 23. First gear; 24. First screw; 25. Piston plate; 26. Piston sleeve rod; 27. Piston rod; 28. Vent hole; 29. ​​Connecting plate; 30. Nut ring; 31. Second gear; 32. First rack; 33. Connecting block; 34. Second rack; 35. Placement groove; 36. Sliding rod; 37. Second screw; 38. Sliding plate; 39. Through hole; 40. Straight groove; 41. Sliding block; 42. Spiral groove. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "opening", "upper", "middle", "length", "inner", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0037] To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and known components are omitted.

[0038] Example 1

[0039] Please see Figures 1-3As shown, this embodiment provides a fault diagnosis device for cryogenic LNG valves, including: a diagnostic box 1 and a valve 8. A support frame 2 is fixedly connected to the top of the diagnostic box 1. An electric push rod 3 is fixedly connected through the top of the support frame 2. A top plate 6 is provided below the electric push rod 3. A rotating connector 13 is fixedly connected to the top of the top plate 6. The rotating connector 13 is connected to an external gas source through a first gas source pipe 12. A hollow disc 18 is rotatably connected through the bottom of the top plate 6. A plurality of nozzles 20 for drying the valve 8 are connected to the bottom of the hollow disc 18.

[0040] Multiple support columns 5 are fixedly connected to the bottom of the top plate 6. The same filter plate 4 is fixedly connected to the bottom of the multiple support columns 5. The filter plate 4 is located inside the diagnostic box 1. A support plate 7 is fixedly connected to the top of the filter plate 4. A placement slot 35 for placing the valve 8 is opened on the top of the support plate 7.

[0041] The top of the filter plate 4 is provided with two clamping plates 9 for holding the valve 8. The two clamping plates 9 are fixedly connected to the side of each other, and sealing cones 10 for sealing the valve 8 are fixedly connected. One of the sealing cones 10 and one side of the clamping plate 9 are connected to the same insertion tube 15. One end of the insertion tube 15 is connected to the external air source through the second air source tube 14 through the top plate 6 for detecting leakage of the valve 8.

[0042] The transmission mechanism, located on the top of the filter plate 4, is used to drive the two clamping plates 9 to move closer together to seal and clamp the valve 8, and to drive the nozzle 20 to rotate to quickly dry the surface of the valve 8. In the above technical solution, the valve 8 is placed on the support plate 7, and then the electric push rod 3 is moved to drive the filter plate 4 to descend. At the same time as it descends, the transmission mechanism can drive the two sealing cones 10 to move closer together to seal and clamp the valve 8. Then, the valve 8 is filled with air through the insertion tube 15 to test the sealing performance. After the test is completed, the nozzle 20 can be driven to rotate and blow air onto the valve 8 to make the valve 8 dry quickly.

[0043] In one aspect of this embodiment, such as Figure 2 and Figure 5As shown, the transmission mechanism includes a nut ring 30 rotatably connected to the top of the filter plate 4. A second gear 31 is fixedly sleeved on the outer wall of the nut ring 30. A first rack 32 and a second rack 34 that mesh with the second gear 31 are slidably provided on the top of the filter plate 4. A connecting block 33 is fixedly connected to one end of the first rack 32 and the second rack 34. The connecting block 33 on the second rack 34 is slidably connected to the first rack 32. A clamping plate 9 is set on the connecting block 33. A first screw 23 is threaded on the inner wall of the nut ring 30. The first screw 23 is fixedly connected to the bottom inner wall of the diagnostic box 1. In the above technical solution, when the filter plate 4 moves downward, the nut ring 30 can be rotated by the thread on the first screw 23. The rotation of the nut ring 30 can drive the second gear 31 to rotate, which can drive the first rack 32 and the second rack 34 to move relative to each other, and drive the two clamping plates 9 to move closer to each other. Thus, the valve 8 can be sealed and clamped by the two sealing cones 10.

[0044] In one aspect of this embodiment, such as Figure 5 As shown, a sliding rod 36 is fixedly connected to the top of the connecting block 33, and the clamping plate 9 is slidably sleeved on the sliding rod 36. A second screw 37 is threadedly connected to the top of the clamping plate 9, and the bottom of the second screw 37 is rotatably connected to the connecting block 33. In the above technical solution, the clamping plate 9 can be driven to rise and fall by rotating the second screw 37. The rise and fall of the clamping plate 9 can adjust the position of the sealing cone 10 and the center line of the valve 8, so that the sealing cone 10 can fit tightly and seal with the valve 8.

[0045] In one aspect of this embodiment, such as Figure 3 , Figure 5 and Figure 6 As shown, a rotating tube 21 is fixedly connected to the top of the nut ring 30. The top of the rotating tube 21 is rotatably connected to the top plate 6. A first gear 22 is fixedly sleeved on the outer wall of the rotating tube 21. An external toothed ring 19 that meshes with the first gear 22 is fixedly sleeved on the outer wall of the hollow disc 18. In the above technical solution, the nut ring 30 can rotate while driving the rotating tube 21 to rotate. The rotating tube 21 drives the external toothed ring 19 to rotate through the first gear 22. The rotation of the external toothed ring 19 can drive the hollow disc 18 to rotate, so that the nozzle 20 can spray air onto the surface of the valve 8 to dry it quickly.

[0046] In one aspect of this embodiment, such as Figure 1 and Figure 6As shown, a base plate 16 is fixedly connected to the bottom of the top plate 6. A sealing ring that mates with the inner wall of the diagnostic box 1 is fitted on the outer wall of the top plate 6. An indicator rod 11 is fixedly connected through the top of the top plate 6. A through hole 39 is opened at the bottom of the indicator rod 11. A sliding plate 38 is slidably provided on the inner wall of the indicator rod 11. In the above technical solution, the top plate 6 can seal the gap between the top plate 6 and the diagnostic box 1. When the valve 8 leaks, the gas inside the diagnostic box 1 will drive the sliding plate 38 to rise through the through hole 39, making it easier to observe the leak.

[0047] Example 2

[0048] An improvement based on Embodiment 1: In one aspect of this embodiment, as follows Figure 4 As shown, a piston sleeve 26 is fixedly connected to the bottom inner wall of the diagnostic box 1. A piston rod 27 is slidably provided on the inner wall of the piston sleeve 26. A connecting plate 29 is fixedly connected to the top of the piston rod 27. The connecting plate 29 is fixedly connected to the filter plate 4. Multiple vent holes 28 are opened on the outer wall of the piston sleeve 26. The same piston plate 25 is slidably provided on the outer wall of the first screw 23 and the piston sleeve 26 and the inner wall of the diagnostic box 1. Multiple limiting blocks 17 that abut against the piston plate 25 are fixedly connected to the bottom inner wall of the diagnostic box 1. In the above technical solution, when the filter plate 4 moves downward, it can drive the piston rod 27 to move downward, squeezing the air in the piston sleeve 26 into the diagnostic box 1, which can drive the piston plate 25 to rise, causing the water at the top of the piston plate 25 to rise, making it easier for the water to submerge the valve 8.

[0049] Example 3

[0050] An improvement based on Embodiment 1: In one aspect of this embodiment, as follows Figure 7 As shown, the outer wall of the first screw 23 is provided with a spiral groove 42 and a straight sliding groove 40, which are connected. A sliding block 41 is fixedly connected to the inner wall of the nut ring 30, and the sliding block 41 is located in the spiral groove 42. In the above technical solution, the setting of the spiral groove 42, the straight sliding groove 40 and the sliding block 41 can make the nut ring 30 descend and rotate more smoothly, and the straight sliding groove 40 can make the two sealing cones 10 descend when clamping the valve 8, so as to avoid the descending and clamping getting stuck together.

[0051] The fault diagnosis method for cryogenic LNG valves includes the following steps:

[0052] S1. First, add an appropriate amount of water to the diagnostic box 1 and make the water level at the top of the piston plate 25. Place the valve 8 in the placement groove 35 on the support plate 7. Start the electric push rod 3. The electric push rod 3 drives the top plate 6 to descend. The top plate 6 drives the filter plate 4 to descend through the support column 5. At the same time as it descends, the sliding block 41 and the spiral groove 42 can drive the nut ring 30 to rotate. The rotation of the nut ring 30 can drive the second gear 31 to rotate. The rotation of the second gear 31 can drive the second rack 34 and the first rack 32 to move relative to each other, causing the two clamping plates 9 to move closer to each other. When the center point of the sealing cone 10 is lower than the center point of the valve 8, rotating the second screw 37 can drive the clamping plate 9 to move upward, and drive the sealing cone 10 to move upward until the sealing cone 10 is coaxial with the center point of the valve 8. Continuing to move downward can drive the two sealing cones 10 to clamp the valve 8, so that the valve 8 is sealed and fixed.

[0053] S2. Then, continue to move downwards to drive the top plate 6 to contact the top of the diagnostic box 1, so that the diagnostic box 1 is sealed. Drive the sliding block 41 to slide in the straight slide groove 40. The two sealing cone blocks 10 are limited. At the same time, drive the piston rod 27 to move downwards in the piston sleeve rod 26. The gas in the piston sleeve rod 26 enters between the piston plate 25 and the diagnostic box 1, which can drive the piston plate 25 to move upwards. This can drive the water on the piston plate 25 to move upwards, so that the water submerges the valve 8.

[0054] S3. Then start the external air source of the second air source pipe 14. The air source delivers gas to the valve 8 through the second air source pipe 14 and the insertion pipe 15. When the valve 8 leaks, the gas inside the diagnostic box 1 will drive the sliding plate 38 to move upward through the through hole 39 so that it can be seen directly. When the valve 8 is well sealed, the sliding plate 38 will not move upward.

[0055] S4. After the test is completed, start the electric push rod 3 to reset, which drives the filter plate 4 to reset. At the same time, it first drives the sliding block 41 to slide upward in the straight slide groove 40. When the sliding block 41 moves into the spiral groove 42, it will drive the second gear 31 to rotate and drive the two clamping plates 9 to move away from each other. At the same time, start the air source on one side of the first air source pipe 12. When the second gear 31 rotates, it can drive the rotating pipe 21 to rotate. The rotating pipe 21 can drive the outer gear ring 19 to rotate through the first gear 22. The outer gear ring 19 drives the hollow disk 18 to rotate, which drives the nozzle 20 to rotate. The nozzle 20 rotates and sprays gas to wash the water stains on the valve 8, so that the surface of the valve 8 dries quickly.

[0056] It should be noted that in the description of this specification, descriptions such as "first" and "second" are only used to distinguish the features and do not have any actual order or directional meaning. This application is not limited to this.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fault diagnosis device for cryogenic LNG valves, characterized in that, include: Diagnostic box (1) and valve (8), the top of the diagnostic box (1) is fixedly connected to a support frame (2), the top of the support frame (2) is fixedly connected to an electric push rod (3), a top plate (6) is provided below the electric push rod (3), the top of the top plate (6) is fixedly connected to a rotating connector (13), the rotating connector (13) is connected to an external air source through a first air source pipe (12), the bottom of the top plate (6) is rotatably connected to a hollow disc (18), the bottom of the hollow disc (18) is connected to multiple nozzles (20) for drying the valve (8); The bottom of the top plate (6) is fixedly connected to a plurality of support columns (5), and the bottom of the plurality of support columns (5) is fixedly connected to the same filter plate (4). The filter plate (4) is located inside the diagnostic box (1), and the top of the filter plate (4) is fixedly connected to a support plate (7). The top of the support plate (7) is provided with a placement slot (35) for placing a valve (8). The top of the filter plate (4) is provided with two clamping plates (9) for clamping the valve (8). The two clamping plates (9) are fixedly connected to a sealing cone (10) for sealing the valve (8) on the side close to each other. One of the sealing cones (10) and one side of the clamping plate (9) are fixedly connected to the same insertion tube (15). One end of the insertion tube (15) is connected to the external air source through the second air source pipe (14) through the top plate (6) for detecting valve (8) leakage. The transmission mechanism is set on the top of the filter plate (4) to drive the two clamping plates (9) to move closer to each other to seal and clamp the valve (8), and to drive the nozzle (20) to rotate to quickly dry the surface of the valve (8); The transmission mechanism includes a nut ring (30) rotatably connected to the top of the filter plate (4), a second gear (31) fixedly sleeved on the outer wall of the nut ring (30), a first rack (32) and a second rack (34) slidably connected to the top of the filter plate (4) and meshing with the second gear (31), a connecting block (33) fixedly connected to one end of the first rack (32) and the second rack (34), the connecting block (33) on the second rack (34) and the first rack (32) being slidably connected through, the clamping plate (9) being set on the connecting block (33), and a first screw (23) threaded on the inner wall of the nut ring (30), the first screw (23) being fixedly connected to the bottom inner wall of the diagnostic box (1); The top of the nut ring (30) is fixedly connected to a rotating tube (21), the top of the rotating tube (21) is rotatably connected to the top plate (6), the outer wall of the rotating tube (21) is fixedly sleeved with a first gear (22), and the outer wall of the hollow disc (18) is fixedly sleeved with an external toothed ring (19) that meshes with the first gear (22).

2. The cryogenic LNG valve fault diagnosis equipment as described in claim 1, characterized in that, The top of the connecting block (33) is fixedly connected to a sliding rod (36), the clamping plate (9) is slidably sleeved on the sliding rod (36), the top of the clamping plate (9) is threadedly connected to a second screw (37), and the bottom of the second screw (37) is rotatably connected to the connecting block (33).

3. The cryogenic LNG valve fault diagnosis equipment as described in claim 1, characterized in that, The bottom of the top plate (6) is fixedly connected to the bottom plate (16). The outer wall of the top plate (6) is fitted with a sealing ring that works in conjunction with the inner wall of the diagnostic box (1). The top of the top plate (6) is fixedly connected to a pointer rod (11). The bottom of the pointer rod (11) is provided with a through hole (39). The inner wall of the pointer rod (11) is slidably provided with a sliding plate (38).

4. The cryogenic LNG valve fault diagnosis equipment as described in claim 1, characterized in that, The bottom inner wall of the diagnostic box (1) is fixedly connected to a piston sleeve (26), and a piston rod (27) is slidably provided on the inner wall of the piston sleeve (26). A connecting plate (29) is fixedly connected to the top of the piston rod (27), and the connecting plate (29) is fixedly connected to the filter plate (4). Multiple ventilation holes (28) are provided on the outer wall of the piston sleeve (26). The same piston plate (25) is slidably provided on the outer wall of the first screw (23) and the piston sleeve (26) and the inner wall of the diagnostic box (1). Multiple limiting blocks (17) that abut against the piston plate (25) are fixedly connected to the bottom inner wall of the diagnostic box (1).

5. The cryogenic LNG valve fault diagnosis equipment as described in claim 1, characterized in that, The outer wall of the first screw (23) is provided with a spiral groove (42) and a straight sliding groove (40), the spiral groove (42) and the straight sliding groove (40) are connected, and a sliding block (41) is fixedly connected to the inner wall of the nut ring (30), the sliding block (41) is located in the spiral groove (42).

6. The method for diagnosing faults in cryogenic LNG valves as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. First, add an appropriate amount of water to the diagnostic box (1) and make the water level on the top of the piston plate (25). Place the valve (8) in the placement slot (35) on the support plate (7). Start the electric push rod (3). The electric push rod (3) drives the top plate (6) to descend. The top plate (6) drives the filter plate (4) to descend through the support column (5). At the same time as it descends, the nut ring (30) can be driven to rotate through the sliding block (41) and the spiral groove (42). The rotation of the nut ring (30) can drive the second gear (31) to rotate. The rotation of wheel (31) can drive the second rack (34) and the first rack (32) to move relative to each other, and drive the two clamping plates (9) to move closer to each other. When the center point of the sealing cone (10) is lower than the center point of the valve (8), rotating the second screw (37) can drive the clamping plate (9) to move upward, and drive the sealing cone (10) to move upward until the sealing cone (10) is coaxial with the center point of the valve (8). Continuing to move downward can drive the two sealing cones (10) to clamp the valve (8), so that the valve (8) is sealed and fixed. S2. Then continue to move downwards to drive the top plate (6) to contact the top of the diagnostic box (1), so that the diagnostic box (1) is sealed, and drive the sliding block (41) to slide in the straight slide groove (40). The two sealing cones (10) are limited, and at the same time drive the piston rod (27) to move downwards in the piston sleeve rod (26). The gas in the piston sleeve rod (26) enters between the piston plate (25) and the diagnostic box (1), which can drive the piston plate (25) to move upwards, thereby driving the water on the piston plate (25) to move upwards, so that the water submerges the valve (8). S3. Then start the gas source outside the second gas source pipe (14). The gas source delivers gas to the valve (8) through the second gas source pipe (14) and the insertion pipe (15). When the valve (8) leaks, the gas inside the diagnostic box (1) will drive the sliding plate (38) to move upward through the through hole (39) so that it can be seen directly. When the valve (8) has good sealing performance, the sliding plate (38) will not move upward. S4. After the test is completed, start the electric push rod (3) to reset, drive the filter plate (4) to reset, and at the same time drive the sliding block (41) to slide upward in the straight slide groove (40). When the sliding block (41) moves into the spiral groove (42), it will drive the second gear (31) to rotate and drive the two clamps (9) to move away from each other. At the same time, start the air source on one side of the first air source pipe (12). When the second gear (31) rotates, it can drive the rotating pipe (21) to rotate. The rotating pipe (21) can drive the external gear ring (19) to rotate through the first gear (22). The external gear ring (19) drives the hollow disk (18) to rotate, and drives the nozzle (20) to rotate. The nozzle (20) rotates and sprays gas to wash the water stains on the valve (8) so that the surface of the valve (8) dries quickly.

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