Ultralow-temperature high-performance self-compensation gate valve

Abstract

The ultralow-temperature high-performance self-compensating gate valve comprises a valve body, a valve cover, a valve rod and a gate plate, the valve cover is installed at the upper end of the valve body, a support is arranged at the upper end of the valve cover, an executing mechanism is installed on the support, and a valve seat is installed on the inner wall of the valve body; the gate plate comprises a gate plate frame, a wedge block, an adjusting ball and two gate plate bodies, an inverted-T-shaped groove is formed in the upper end of the wedge block, a valve rod nut is arranged in the inverted-T-shaped groove, and the lower end of the valve rod extends into the inverted-T-shaped groove and is in threaded fit with the valve rod nut; a guide channel is arranged on the flashboard frame, the two flashboard bodies are symmetrically arranged on the two sides of the flashboard frame, guide bodies in sliding fit with the guide channel are arranged on the flashboard bodies, guide slopes matched with the corresponding sides of the wedge blocks are arranged on the guide bodies, and a plurality of limiting pieces used for limiting the sliding stroke of the flashboard bodies are further arranged on the flashboard frame. It can be guaranteed that the valve stably operates under the low-temperature or ultralow-temperature working condition, and external leakage and internal leakage of a low-temperature medium are eradicated.

Description

Technical Field

[0001] This invention relates to the field of valve technology, and in particular to a stable, high-performance, self-compensating gate valve operating at ultra-low temperatures. Background Technology

[0002] With the rapid development of modern industry, especially aerospace, new energy (hydrogen energy), large-scale natural gas liquefaction and storage, superconducting technology, and cutting-edge scientific experimental facilities, the demand for valves that can operate stably and reliably in ultra-low temperature environments (usually below -100℃, especially below -196℃) and even cryogenic environments (below -253℃) is becoming increasingly urgent. Gate valves, due to their advantages such as low flow resistance, long opening and closing stroke, and reliable sealing, are important shut-off devices in pipeline systems. However, when the operating temperature drops to the ultra-low temperature range, the design of conventional valves and ordinary cryogenic valves faces a series of extreme challenges, and existing technologies have significant shortcomings. As key control valves in pipelines, the sealing performance and performance stability of cryogenic valves are of paramount importance.

[0003] Traditional gate valves, when used in low-temperature or ultra-low-temperature conditions, have the following insurmountable drawbacks: (1) High risk of seal failure: Metal seals have extremely high requirements for processing accuracy and assembly, and are easily damaged when impurities are present. In addition, the sealing pair is prone to stress deformation under ultra-low temperature medium, which leads to seal failure.

[0004] (2) Valve stem seal failure: Traditional cryogenic valves use an extended valve stem structure. Under long-term heat exchange, the packing temperature drops below zero and freezes, which can easily lead to seal failure at the valve stem packing and cause external leakage.

[0005] (3) Significant energy loss and safety hazards: The valve body, valve cover, and valve stem form a continuous metal "thermal bridge," causing external heat to continuously enter, resulting in medium vaporization loss and severe frost and ice formation on the outside of the valve. This not only increases energy consumption but also poses a threat to the safety of operators, and the frozen ice layer may also jam the operating mechanism.

[0006] Therefore, it is necessary to improve the existing gate valve structure to ensure that the valve can operate stably under low temperature or ultra-low temperature conditions. Summary of the Invention

[0007] The purpose of this invention is to provide a high-performance self-compensating gate valve for ultra-low temperature conditions. This invention can ensure the stable operation of the valve under low or ultra-low temperature conditions, and eliminate external and internal leakage of low temperature media. It is of great significance to the future development of the new energy market.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a high-performance self-compensating gate valve for cryogenic applications, comprising a valve body, a valve cover, a valve stem, and a gate. The valve cover is mounted on the upper end of the valve body, and a bracket is provided on the upper end of the valve cover. An actuator is mounted on the bracket, and the output end of the actuator is linked to the valve stem. The bracket and the valve cover are respectively provided with an upper shaft hole and a lower shaft hole. The valve stem passes through the upper shaft hole and the lower shaft hole and extends into the valve body to be linked to the gate. A valve stem is installed on the inner wall of the valve body at positions corresponding to both sides of the gate to form a sealing fit with the gate when the valve is closed. The valve seat; the gate includes a gate frame, a wedge block, an adjusting ball, and two gate bodies. The upper end of the wedge block is provided with an inverted T-shaped groove, and a valve stem nut is provided in the inverted T-shaped groove. The lower end of the valve stem extends into the inverted T-shaped groove and is threadedly engaged with the valve stem nut. The gate frame is provided with a guide channel, and the two gate bodies are symmetrically arranged on both sides of the gate frame. The gate body is provided with a guide body that slides with the guide channel. The guide body is provided with a guide slope that cooperates with the corresponding side of the wedge block. The gate frame is also provided with multiple limiting components for limiting the sliding stroke of the gate body.

[0009] By adopting the above technical solution, the actuator drives the valve stem and wedge block to move downwards. The wedge block and the inclined surfaces of the two gate bodies generate a horizontal force on each gate body, pressing the two gate bodies onto their respective valve seats, thereby achieving bidirectional forced sealing at the inlet and outlet. The sealing performance meets the Class V requirements of ANSI / FCI 70-2 control valves.

[0010] The invention is further configured such that the wedge block includes two symmetrically arranged semi-wedges, each with a hemispherical groove on its opposite side, and the left and right parts of the adjusting ball are respectively disposed in the corresponding hemispherical grooves; the valve stem nut is vertically movable in the inverted T-shaped groove under the action of the valve stem, and a limiting step is provided on the outer periphery of the valve stem, with a cup-shaped disc spring sandwiched between the limiting step and the gate frame.

[0011] By adopting the above technical solution, the ball setting is adjusted to ensure smooth contact between the two semi-wedge-shaped inclined surfaces and the gate body inclined surface, guaranteeing that the horizontal force pressing the two gate bodies against the valve seat is evenly applied to the valve seat. The cup-shaped disc spring structure and buffer stroke assist the gate to disengage from the valve seat, eliminating hard friction between the gate and valve seat sealing surfaces during valve opening and closing. This results in lighter valve opening and closing torque, reducing the selection cost of the actuator, and solving problems such as easy pressure wedging, inability to open and close normally, and easy wear of the sealing surface in conventional valves due to temperature rise in the cavity, ensuring long-term effective operation of the valve.

[0012] The present invention is further configured such that the limiting member includes a limiting rod passing through the gate frame and a limiting nut threadedly connected to both ends of the limiting rod, and a limiting flange is provided on the outer periphery of the gate body, the limiting flange being movably disposed between the gate frame and the limiting nut.

[0013] By adopting the above technical solution, multiple evenly distributed limiting components are set outside the gate frame to prevent the two gate bodies, wedge blocks, and adjusting balls from separating and falling from the gate frame, which would cause the gate to disintegrate.

[0014] The present invention is further configured such that an installation groove for installing a valve seat is respectively opened on the inner wall of the valve body at the position corresponding to both sides of the gate plate, and a first bellows assembly is provided in the installation groove. One end of the first bellows assembly is welded to the inner end of the installation groove, and the other end of the first bellows assembly is welded to the valve seat. A lip ring for forming a sealing fit with the inner surface of the installation groove is also installed on the outer circular surface of the valve seat.

[0015] By adopting the above technical solution, the valve seat adopts a bellows floating elastic sealing structure, which has compensation and protection functions, namely: (1) Thermal expansion and contraction compensation: When the temperature changes, the material expansion coefficients of the valve body, gate and valve seat are different. Under the support of the bellows elasticity, the floating valve seat can move slightly axially to automatically compensate for this difference and avoid sealing failure or jamming due to thermal stress. (2) Wear compensation: After long-term use, the sealing surface will have a small amount of wear. The elasticity of the bellows will continuously push the valve seat forward to compensate for the wear and maintain sealing contact.

[0016] The invention is further configured such that the valve stem includes an upper valve stem, an upper heat insulation sleeve head, a heat insulation sleeve, a lower heat insulation sleeve head, and a lower valve stem. The upper and lower heat insulation sleeve heads are respectively threaded to the upper and lower ends of the heat insulation sleeve and welded to each other. The heat insulation sleeve is equipped with multiple vacuum check valves that only allow the medium inside the heat insulation sleeve to be discharged outward. The outer diameters of the upper heat insulation sleeve head, the heat insulation sleeve, and the lower heat insulation sleeve head are all smaller than the inner diameter of the lower shaft hole. An upper guide ring and a lower guide ring that fit against the inner wall of the lower shaft hole are respectively installed on the outer periphery of the upper and lower heat insulation sleeve heads. The upper end of the upper heat insulation sleeve head is threaded to the lower end of the upper valve stem and then fixed by an upper shaft pin. The lower end of the lower heat insulation sleeve head is threaded to the upper end of the lower valve stem and then fixed by a lower shaft pin.

[0017] By adopting the above technical solution, the valve stem uses a segmented double-layer vacuum wall heat insulation sleeve. Before connecting and installing the heat insulation sleeve with the upper and lower valve stems, it is evacuated to a high vacuum (<10^-3 Pa). The high vacuum environment almost completely eliminates gas convection and conduction heat transfer, preventing the low temperature of the medium in the valve body from being conducted to the upper valve stem and packing. At the same time, upper and lower PCTFE guide rings are provided on the outside of the heat insulation sleeve to prevent the valve stem from deflection and instability caused by the closing force of the actuator when the valve is closed, and to prevent the valve stem from scraping against the valve cover during the opening and closing process.

[0018] The invention is further configured to include a packing assembly and a second bellows assembly. The packing assembly includes a packing pressure plate, a packing sleeve, and a sealing packing, which are sequentially fitted around the outer periphery of the upper valve stem from top to bottom. The bracket has a sealing groove at the upper end of the upper shaft hole. The packing pressure plate is connected to the valve cover by a snap-fit ​​bolt. The packing pressure plate acts on the packing sleeve, causing the packing sleeve to press the sealing packing into the sealing groove. The second bellows assembly is fitted around the outer periphery of the upper valve stem. The upper end of the second bellows assembly is sandwiched between the bracket and the valve cover, and the lower end of the second bellows assembly is welded to the outer periphery of the upper valve stem.

[0019] By adopting the above technical solution, a dual-seal structure design is used on the valve stem, namely a bellows main seal and a packing auxiliary seal structure. The valve stem is welded to the bellows to isolate the medium in the middle cavity from the valve stem. When the bellows fails, the valve stem packing serves as a backup sealing system to achieve a secondary seal at the valve stem, preventing large-scale media leakage and providing valuable reaction time and safety assurance for system shutdown and maintenance.

[0020] The invention is further configured to include a steam circulation sleeve, and the inner end of the sealing groove is provided with an installation cavity. The outer wall of the bracket is provided with a steam inlet and a steam outlet communicating with the installation cavity. The steam circulation sleeve is disposed in the installation cavity, the upper end of the steam circulation sleeve extends into the sealing groove, and the outer periphery of the upper end of the steam circulation sleeve is provided with a sealing flange. A sealing gasket is sandwiched between the lower end of the sealing flange and the inner end of the sealing groove, and between the lower end of the steam circulation sleeve and the inner end of the installation cavity. The outer periphery of the steam circulation sleeve is provided with a spirally distributed air inlet channel and a return channel. The air inlet channel and the return channel are staggered. The upper end of the air inlet channel and the upper end of the return channel are respectively connected to the steam inlet and the steam outlet. The lower end of the air inlet channel and the lower end of the return channel are connected together.

[0021] By adopting the above technical solution, a steam circulation sleeve is set between the packing and the bellows assembly, and steam is used for heat exchange, which can prevent the packing from freezing and failing to seal due to heat exchange of ultra-low temperature medium in the valve cavity.

[0022] The present invention is further configured such that the valve body and the valve cover are covered with a heat insulation sleeve, and the heat insulation sleeve is filled with a pipe insulation layer; an isolation drip plate is also vertically movable on the outer periphery of the valve cover, and an isolation drip plate lower connecting sleeve is welded to the upper end of the heat insulation sleeve, and the isolation drip plate and the isolation drip plate lower connecting sleeve are connected together by an isolation drip plate telescopic sleeve.

[0023] By adopting the above technical solution, axial expansion and contraction can be achieved through the expansion sleeve of the isolation drip plate to compensate for the installation error between the valve isolation drip plate and the pipeline insulation layer, as well as the displacement caused by the thermal expansion and contraction of the pipeline, ensuring effective insulation of the valve part, and facilitating disassembly and assembly during valve maintenance.

[0024] The invention is further configured such that a self-grinding assembly is provided between the valve stem and the valve cover. The self-grinding assembly includes a guide sleeve, a grinding sleeve, a drive ball, a limiting plug, and two bearings. The guide sleeve is installed inside the valve cover, and the inner diameter of the guide sleeve is approximately equal to the inner diameter of the lower shaft hole. The grinding sleeve is disposed between the valve stem and the guide sleeve. Multiple grinding helical teeth for scraping off deposits from the inner wall of the lower shaft hole are evenly distributed on the outer circumference of the upper end of the grinding sleeve. An isolation gap is provided between the grinding sleeve and the valve stem. A positioning groove is respectively formed on the inner wall of the grinding sleeve at the upper and lower ends. The outer ring of the bearing is embedded in the corresponding positioning groove. In the process, a retaining ring is respectively attached to the upper and lower positions of the two bearings on the outer periphery of the valve stem, and the retaining ring abuts against the inner ring end of the corresponding bearing; a spiral guide groove is formed vertically on the outer circumference of the grinding sleeve, and a fixing hole corresponding to the spiral guide groove is formed on the side wall of the guide sleeve; half of the driving ball is set in the spiral guide groove and the other half is set in the fixing hole; the limiting plug is threaded to the outer end of the fixing hole to limit the driving ball; an annular groove is also provided on the inner wall of the guide sleeve, and multiple inclined downward extending discharge holes are provided in the annular groove and penetrate to the outer wall of the guide sleeve.

[0025] By adopting the above technical solution, when the valve stem moves axially, the spiral guide sleeve on the grinding sleeve cooperates with the drive ball. The circumferential component of the drive ball on the grinding sleeve causes the grinding sleeve to rotate circumferentially. As the grinding sleeve moves axially, the grinding helical teeth on its outer periphery will scrape off the impurities or ice particles attached to the inner wall of the lower shaft hole, thereby preventing the valve stem from getting stuck. In addition, the upper and lower ends of the grinding sleeve cooperate with the valve stem through bearings, resulting in minimal friction.

[0026] The present invention is further configured such that the grinding sleeve includes a movable body and a grinding head disposed on the upper end of the movable body, the grinding helical teeth are disposed on the grinding head, the lower end of the grinding head is provided with an annular connecting part, the upper end of the movable body is provided with an annular connecting groove, the annular connecting part and the annular connecting groove are fitted together and fixed together by a plurality of circumferentially distributed connecting screws.

[0027] By adopting the above technical solution, the grinding sleeve corresponding to the grinding helical teeth (grinding head) adopts a detachable structure, which facilitates replacement after wear and reduces the maintenance cost.

[0028] The present invention is further configured such that the valve cover and the valve body are made of high-manganese austenitic alloy structural steel.

[0029] By adopting the above technical solutions, high-manganese austenitic alloy structural steel has excellent low-temperature impact toughness. When encountering extreme temperature shocks, pressure fluctuations, or unexpected mechanical loads, it can absorb a large amount of energy through plastic deformation, greatly resisting brittle fracture and fundamentally ensuring the inherent safety of valves and pipeline systems. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the gate structure of the present invention; Figure 3 This is a schematic diagram of the gate plate when the valve is closed according to the present invention; Figure 4 This is a schematic diagram of the gate plate when the valve is opened according to the present invention; Figure 5 This is an exploded view of the gate of the present invention; Figure 6 This is a schematic diagram of the valve seat structure of the present invention; Figure 7 This is a schematic diagram of the structure of the valve stem heat insulation sleeve of the present invention; Figure 8 This is a schematic diagram of the double sealing structure of the valve stem of the present invention; Figure 9 This is a schematic diagram of the steam circulation antifreeze structure of the present invention; Figure 10 This is a perspective view of the steam circulation sleeve of the present invention; Figure 11 This is an exploded view of the steam circulation sleeve of the present invention; Figure 12 A schematic diagram of the structure of the telescopic isolation drip plate of the present invention; Figure 13 This is a schematic diagram of the structure of the present invention after adding the self-grinding component; Figure 14 This is an enlarged view of the self-grinding component of the present invention; Figure 15 This is a perspective view of the self-grinding component of the present invention; Figure 16 This is an exploded view of the self-grinding component of the present invention.

[0031] In the diagram: 1. Valve body; 2. Valve cover; 3. Valve stem; 4. Gate; 5. Bracket; 6. Actuator; 7. Upper shaft hole; 8. Lower shaft hole; 9. Valve seat; 10. Gate bracket; 11. Wedge block; 12. Adjusting ball; 13. Gate body; 14. Inverted T-groove; 15. Valve stem nut; 16. Guide channel; 17. Guide body; 18. Guide slope; 19. Limiting element; 20. Semi-wedge; 21. Hemispherical groove; 22. Limiting step; 3. Cup-shaped disc spring; 24. Limiting rod; 25. Limiting nut; 26. Limiting flange; 27. Mounting groove; 28. First bellows assembly; 29. ​​Lip ring; 30. Upper valve stem; 31. Upper insulation sleeve head; 32. Insulation sleeve; 33. Lower insulation sleeve head; 34. Lower valve stem; 35. Vacuum check valve; 36. Upper guide ring; 37. Lower guide ring; 38. Upper shaft pin; 39. Lower shaft pin; 40. Packing assembly; 41. Second bellows assembly. 42. Packing gland; 43. Packing sleeve; 44. Sealing packing; 45. Sealing groove; 46. Union bolt; 47. Steam circulation sleeve; 48. Mounting cavity; 49. Steam inlet; 50. Steam outlet; 51. Sealing flange; 52. Sealing gasket; 53. Air inlet channel; 54. Return channel; 55. Insulation sleeve; 56. Pipe insulation layer; 57. Isolation drip plate; 58. Isolation drip plate telescopic sleeve; 59. Self-grinding assembly Components; 60. Guide sleeve; 61. Grinding sleeve; 62. Drive ball; 63. Limiting plug; 64. Bearing; 65. Grinding helical teeth; 66. Isolation gap; 67. Positioning groove; 68. Snap ring; 69. Spiral guide groove; 70. Fixing hole; 71. Annular groove; 72. Discharge hole; 73. Movable body; 74. Grinding head; 75. Annular connecting part; 76. Annular connecting groove; 77. Connecting screw; 78. Isolation drip plate lower connecting sleeve. Detailed Implementation

[0032] 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.

[0033] Example: As attached Figures 1-16The ultra-low temperature high-performance self-compensating gate valve shown includes a valve body 1, a valve cover 2, a valve stem 3, and a gate 4. The valve cover 2 is bolted to the upper end of the valve body 1. A bracket 5 is bolted to the upper end of the valve cover 2, and an actuator 6 is mounted on the bracket 5. The actuator 6 can be a handwheel, a pneumatic actuator, or a hydraulic actuator. The output end of the actuator 6 is linked to the valve stem 3. The bracket 5 and the valve cover 2 are respectively provided with an upper shaft hole 7 and a lower shaft hole 8. The valve stem 3 passes through the upper shaft hole 7 and the lower shaft hole 8 and extends into the valve body 1 to be linked to the gate 4. A valve seat 9 is installed on the inner wall of the valve body 1 at positions corresponding to both sides of the gate 4 to form a sealing fit with the gate 4 when the valve is closed. The gate 4 includes a gate frame 10, a wedge block 11, and an adjusting ball. The valve body 1 is equipped with a valve stem nut 15 and two gate bodies 13. The upper end of the wedge block 11 is provided with an inverted T-shaped groove 14. The valve stem 3 is provided with a valve stem nut 15 inside the inverted T-shaped groove 14. The lower end of the valve stem 3 extends into the inverted T-shaped groove 14 and is threadedly engaged with the valve stem nut 15. The gate frame 10 is provided with a guide groove along the vertical direction. The inner wall of the valve body 1 is provided with a guide rib that cooperates with the guide groove along the vertical direction. The gate frame 10 is provided with a guide channel 16. The two gate bodies 13 are symmetrically arranged on both sides of the gate frame 10. The gate body 13 is provided with a guide body 17 that forms a sliding engagement with the guide channel 16. The guide body 17 is provided with a guide slope 18 that cooperates with the corresponding side of the wedge block 11. The gate frame 10 is also provided with a plurality of limiting members 19 for limiting the sliding stroke of the gate body 13. The wedge block 11 includes two symmetrically arranged semi-wedges 20, each with a hemispherical groove 21 on its opposite side. The left and right parts of the adjusting ball 12 are respectively located in the corresponding hemispherical grooves 21. The valve stem nut 15 is vertically movable in the inverted T-groove 14 under the action of the valve stem 3, meaning that the valve stem nut 15 can move up and down a certain distance in the horizontal groove of the inverted T-groove 14. The valve stem 3 also has a limiting step 22 on its outer periphery, and a cup-shaped disc spring 23 is sandwiched between the limiting step 22 and the gate frame 10. The limiting member 19 includes a limiting rod 24 passing through the gate frame 10 and limiting nuts 25 threaded to both ends of the limiting rod 24. The gate body 13 has a limiting flange 26 on its outer periphery, which is movably disposed between the gate frame 10 and the limiting nut 25.

[0034] The operating principle of this ultra-low temperature high-performance self-compensating gate valve is as follows: (1) Close the valve: as shown in the attached document Figure 2 and attached Figure 3As shown, the actuator 6 drives the valve stem 3 and wedge block 11 to move downwards. The wedge block 11, along with the inclined surfaces of the two gate bodies 13, generates a horizontal force on each gate body 13, pressing them against their respective valve seats 9, achieving a bidirectional forced seal at the inlet and outlet. The adjusting ball 12 ensures smooth contact between the inclined surfaces of the two semi-wedge bodies 20 and the inclined surfaces of the gate bodies 13, guaranteeing that the horizontal force exerted by the two gate bodies 13 on the valve seats 9 is evenly distributed.

[0035] (2) Opening the valve: as shown in the attached document Figure 2 and attached Figure 4 As shown, when the valve is opened, the actuator 6 operates, driving the valve stem 3 and the wedge block 11 to move upward. At the same time, the two gate bodies 13 remain in their original positions under the buffer stroke and the downward thrust of the cup-shaped disc spring 23. Under the action of the large inclination of the wedge block 11 and the two gate bodies 13, the wedge block 11 disengages from the two gate bodies 13. Under the combined action of the actuator 6 and the thrust of the medium, the two gate bodies 13 retract and disengage from the sealing surface of the valve seat 9. During the valve opening process, the guide groove of the gate frame 10 moves vertically up and down on the guide rib of the valve body 1 until the valve is fully opened. Multiple evenly distributed limiting members 19 are provided on the outside of the gate frame 10 to prevent the two gate bodies 13, the wedge block 11, and the adjusting ball 12 from separating from the gate frame 10 and falling off, which would cause the gate 4 to disintegrate.

[0036] When adjusting the wedge-shaped power structure of the ball 12 to close the valve, the adjusting ball 12 can automatically adjust the angle error between the wedge block 11 and the gate body 13, so that the inclined surfaces of the two half-wedge bodies 20 and the inclined surfaces of the gate body 13 can make stable contact, ensuring that the horizontal force of the two gate bodies 13 pressing against the valve seat 9 is evenly applied to the valve seat 9, preventing the sealing pair (valve seat 9, gate 4) from stress deformation and sealing failure under ultra-low temperature conditions.

[0037] The cup-shaped disc spring 23 structure and the buffer stroke assist the gate 4 to disengage from the valve seat 9. During the valve opening and closing process, there is no hard friction between the sealing surfaces of the gate 4 and the valve seat 9, resulting in light valve opening and closing torque. This reduces the selection cost of the actuator 6 and solves the problems of conventional valves being prone to pressure wedging, inability to open and close normally, and easy wear of the sealing surface when the cavity heats up, ensuring long-term effective operation of the valve.

[0038] The gate's internal wedge self-adjusting structure enables bidirectional forced sealing of the valve, achieving sealing performance that meets the ANSI / FCI 70-2 control valve Class V requirements.

[0039] As attached Figure 6As shown, the inner wall of the valve body 1 is provided with a mounting groove 27 for mounting the valve seat 9 on both sides of the gate plate 4. The mounting groove 27 is provided with a first bellows assembly 28. One end of the first bellows assembly 28 is welded to the inner end of the mounting groove 27, and the other end of the first bellows assembly 28 is welded to the valve seat 9. A lip ring 29 for forming a sealing fit with the inner surface of the mounting groove 27 is also installed on the outer circular surface of the valve seat 9.

[0040] It adopts a bellows-type floating elastic sealing structure, with valve seat 9 connected to valve body 1 via an elastic bellows. When the valve is closed, the bellows provides initial elastic pre-tightening force, achieving an initial seal between valve seat 9 and gate 4. When medium pressure enters from the valve inlet side, the pressure acts on the inner wall of the bellows, creating a pressure difference between the inner and outer walls, causing individual bellows to elongate. This pressure pushes the bellows and valve seat 9 axially, causing the sealing surface of valve seat 9 to press against gate 4 with greater force. The higher the pressure, the greater the sealing specific pressure, forming a "self-tightening" seal. At this time, the bellows mainly serves as a follow-up compensation and main sealing barrier.

[0041] Compensation and Protection Functions: Thermal Expansion and Contraction Compensation: When the temperature changes, the materials of valve body 1, gate 4, and valve seat 9 have different coefficients of thermal expansion. Supported by the elasticity of the bellows, the floating valve seat 9 can move slightly axially, automatically compensating for this difference and preventing sealing failure or jamming due to thermal stress. Wear Compensation: After long-term use, the sealing surface will experience slight wear. The elasticity of the bellows will continuously push the valve seat 9 forward, compensating for the wear and maintaining sealing contact.

[0042] As attached Figure 7 As shown, the valve stem 3 includes an upper valve stem 30, an upper heat insulation sleeve head 31, a heat insulation sleeve 32, a lower heat insulation sleeve head 33, and a lower valve stem 34. The upper heat insulation sleeve head 31 and the lower heat insulation sleeve head 33 are respectively threaded to the upper and lower ends of the heat insulation sleeve 32 and welded to each other. Multiple vacuum check valves 35 are installed on the heat insulation sleeve 32, allowing only the medium inside the heat insulation sleeve 32 to be discharged outwards. The outer diameters of the upper heat insulation sleeve head 31, the heat insulation sleeve 32, and the lower heat insulation sleeve head 33 are all smaller than the inner diameter of the lower shaft hole 8. An upper guide ring 36 and a lower guide ring 37 that fit against the inner wall of the lower shaft hole 8 are respectively installed on the outer periphery of the upper heat insulation sleeve head 31 and the lower heat insulation sleeve head 33. The upper end of the upper heat insulation sleeve head 31 is threadedly engaged with the lower end of the upper valve stem 30 and then fixed by the upper shaft pin 38. That is, the lower end of the upper valve stem 30 and the upper end of the lower valve stem 34 are respectively provided with threaded grooves. The upper heat insulation sleeve head 31 and the lower heat insulation sleeve head 33 are respectively provided with threaded heads. The lower end of the lower heat insulation sleeve head 33 is threadedly engaged with the upper end of the lower valve stem 34 and then fixed by the lower shaft pin 39.

[0043] The valve stem 3 adopts a segmented double-layer vacuum wall heat insulation sleeve 32. Before being connected and installed with the upper valve stem 30 and the lower valve stem 34, the heat insulation sleeve 32 is evacuated to a high vacuum (<10^-3 Pa). The high vacuum environment almost completely eliminates gas convection and conduction heat transfer, preventing the low temperature of the medium in the valve body 1 from being conducted to the upper valve stem 30 and the packing position. At the same time, the heat insulation sleeve 32 is provided with upper and lower PCTFE guide rings to prevent the valve stem 3 from deflecting and becoming unstable due to the closing force of the actuator 6 when the valve is closed, and to prevent the valve stem 3 from scraping against the valve cover 2 during the opening and closing process.

[0044] As attached Figure 8 As shown, it also includes a packing assembly 40 and a second bellows assembly 41. The packing assembly 40 includes a packing pressure plate 42, a packing sleeve 43, and a sealing packing 44, which are sequentially fitted around the outer periphery of the upper valve stem 30 from top to bottom. The bracket 5 has a sealing groove 45 at the position corresponding to the upper end of the upper shaft hole 7. The packing pressure plate 42 is connected to the valve cover 2 by a snap bolt 46. The packing pressure plate 42 acts on the packing sleeve 43, so that the packing sleeve 43 presses the sealing packing 44 into the sealing groove 45. The second bellows assembly 41 is fitted around the outer periphery of the upper valve stem 30. The upper end of the second bellows assembly 41 is sandwiched between the bracket 5 and the valve cover 2, and the lower end of the second bellows assembly 41 is welded to the outer periphery of the upper valve stem 30.

[0045] The ultra-low temperature high-performance self-compensating gate valve adopts a double sealing structure design on the valve stem 3, namely, a bellows main seal and a packing auxiliary seal structure. The valve stem 3 is welded to the bellows to isolate the medium in the middle cavity from the valve stem 3. When the bellows fails, the packing on the valve stem 3 serves as a backup sealing system to achieve a secondary seal at the valve stem 3, preventing large-scale media leakage and providing valuable reaction time and safety assurance for system shutdown and maintenance.

[0046] As attached Figures 9-11 As shown, it also includes a steam circulation sleeve 47. The inner end of the sealing groove 45 is also provided with an installation cavity 48. The outer wall of the bracket 5 is provided with a steam inlet 49 and a steam outlet 50 that communicate with the installation cavity 48. The steam circulation sleeve 47 is disposed in the installation cavity 48. The upper end of the steam circulation sleeve 47 extends into the sealing groove 45, and a sealing flange 51 is provided on the outer periphery of the upper end of the steam circulation sleeve 47. Sealing gaskets 52 are sandwiched between the lower end of the sealing flange 51 and the inner end of the sealing groove 45, and between the lower end of the steam circulation sleeve 47 and the inner end of the installation cavity 48. The outer periphery of the steam circulation sleeve 47 is provided with a spirally distributed air intake channel 53 and a return channel 54. The air intake channel 53 and the return channel 54 are staggered. The upper end of the air intake channel 53 and the upper end of the return channel 54 are respectively connected to the steam inlet 49 and the steam outlet 50. The lower end of the air intake channel 53 and the lower end of the return channel 54 are connected together.

[0047] A steam circulation sleeve 47 is provided between the packing assembly 40 and the second bellows assembly 41 of the ultra-low temperature high-performance self-compensating gate valve to prevent the packing from freezing and failing due to heat exchange of the ultra-low temperature medium in the valve cavity.

[0048] The steam circulation sleeve 47 adopts a double spiral structure. High-temperature steam enters the downward spiral intake channel 53 through the steam inlet 49 of the support 5, flows through the bottom and is discharged from the steam outlet 50 through the upward spiral return channel 54. When the steam medium flows through, it causes the temperature of the valve stem 3 and the support 5 to rise, preventing leakage caused by the packing of the valve stem 3 freezing.

[0049] As attached Figure 12 As shown, the valve body 1 and valve cover 2 are also covered with a heat insulation sleeve 55, and the heat insulation sleeve 55 is filled with a pipeline insulation layer 56. A vertically movable isolation drip plate 57 is also provided on the outer periphery of the valve cover 2. A lower connecting sleeve 78 for the isolation drip plate is welded to the upper end of the heat insulation sleeve 55. The isolation drip plate 57 and the lower connecting sleeve 78 are connected together by an isolation drip plate telescopic sleeve 58. Its structure allows for axial expansion and contraction through the isolation drip plate telescopic sleeve 58 (metal bellows) to compensate for installation errors between the valve isolation drip plate 57 and the pipeline insulation layer 56, and displacement caused by thermal expansion and contraction of the pipeline, ensuring effective heat insulation of the valve area and facilitating valve disassembly and assembly during maintenance.

[0050] As attached Figures 13-16As shown, a self-grinding assembly 59 is also provided between the valve stem 3 and the valve cover 2. The self-grinding assembly 59 includes a guide sleeve 60, a grinding sleeve 61, a drive ball 62, a limiting plug 63, and two bearings 64. The guide sleeve 60 is installed inside the valve cover 2, and the inner diameter of the guide sleeve 60 is approximately equal to the inner diameter of the lower shaft hole 8. The grinding sleeve 61 is disposed between the valve stem 3 and the guide sleeve 60. Multiple grinding helical teeth 65 for scraping off the adhering material on the inner wall of the lower shaft hole 8 are evenly distributed on the outer circumference of the upper end of the grinding sleeve 61. An isolation gap 66 is provided between the grinding sleeve 61 and the valve stem 3. A positioning groove 67 is respectively opened at the upper and lower ends of the inner wall of the grinding sleeve 61. The outer ring of the bearing 64 is embedded in the corresponding positioning groove 67. The valve stem 3 is also fitted with a retaining ring 68 at the position above and below the two bearings 64 on its outer periphery. The retaining ring 68 abuts against the inner ring end of the corresponding bearing 64. The grinding sleeve 61 has a spiral guide groove 69 vertically opened on its outer circular surface. The guide sleeve 60 has a fixing hole 70 corresponding to the spiral guide groove 69 on its side wall. Half of the driving ball 62 is set in the spiral guide groove 69 and the other half is set in the fixing hole 70. The limiting plug 63 is threaded to the outer end of the fixing hole 70 to limit the driving ball 62. The guide sleeve 60 also has an annular groove 71 on its inner wall. The annular groove 71 has a plurality of downwardly inclined discharge holes 72 that extend through to the outer wall of the guide sleeve 60. When the valve stem 3 moves axially, the spiral guide sleeve 60 on the grinding sleeve 61 cooperates with the drive ball 62. The circumferential component of the force exerted by the drive ball 62 on the grinding sleeve 61 causes the grinding sleeve 61 to rotate circumferentially. As the grinding sleeve 61 moves axially, the grinding helical teeth 65 on its outer periphery scrape off the impurities or ice particles attached to the inner wall of the lower shaft hole 8, thereby preventing the valve stem 3 from getting stuck. Furthermore, the upper and lower ends of the grinding sleeve 61 cooperate with the valve stem 3 through the bearing 64, resulting in minimal friction.

[0051] As attached Figure 14 and attached Figure 16 As shown, the grinding sleeve 61 includes a movable body 73 and a grinding head 74 disposed on the upper end of the movable body 73. Grinding helical teeth 65 are disposed on the grinding head 74. The lower end of the grinding head 74 has an annular connecting portion 75, and the upper end of the movable body 73 has an annular connecting groove 76. The annular connecting portion 75 and the annular connecting groove 76 are fitted together and fixed together by multiple circumferentially distributed connecting screws 77. The part of the grinding sleeve 61 corresponding to the grinding helical teeth 65 (grinding head 74) adopts a detachable structure, which facilitates replacement after wear and reduces subsequent maintenance costs.

[0052] In addition, the valve body 1 and valve cover 2 mentioned above can be made of a new type of high-manganese austenitic alloy structural steel.

[0053] Regarding novel high-manganese austenitic alloy structural steel, the applicant's earlier Chinese invention patent application, CN202410011212.3, discloses a high-manganese austenitic steel for cryogenic valves and a method for preparing its castings, which provides a detailed description. This material can easily exceed 150 joules, and even reach over 200 joules, in Charpy V-notch impact energy (KV2) at -254℃ (liquid hydrogen temperature).

[0054] Traditional low-temperature austenitic stainless steels such as 304L and 316L have an impact energy of approximately 100-120 Joules at -196°C, and their austenitic structure undergoes martensitic transformation at low temperatures, leading to deformation. Ordinary carbon steel, on the other hand, becomes completely brittle at low temperatures. New high-manganese steel, however, is a fully austenitic material that does not undergo phase transformation and possesses excellent low-temperature impact toughness. When subjected to extreme temperature shocks, pressure fluctuations, or unexpected mechanical loads, it can absorb a large amount of energy through plastic deformation, greatly resisting brittle fracture and fundamentally ensuring the inherent safety of valves and piping systems. This is crucial for systems storing flammable and explosive cryogenic media (such as LNG).

[0055] The new high-manganese steel has higher strength than traditional low-temperature austenitic stainless steel. The key pressure-bearing components of the valve (such as valve body 1 and valve cover 2) can be designed with thinner walls while ensuring a sufficient safety factor, thereby reducing the overall weight of the valve and lowering the cost. This is of great significance for large LNG storage tank outlet valves, marine valves, etc.

Claims

1. A high-performance self-compensating gate valve for ultra-low temperature applications, comprising a valve body (1), a valve cover (2), a valve stem (3), and a gate (4), wherein the valve cover (2) is installed on the upper end of the valve body (1), a bracket (5) is provided on the upper end of the valve cover (2), an actuator (6) is installed on the bracket (5), the output end of the actuator (6) is linked to the valve stem (3), an upper shaft hole (7) and a lower shaft hole (8) are respectively provided on the bracket (5) and the valve cover (2), the valve stem (3) passes through the upper shaft hole (7) and the lower shaft hole (8) and extends into the interior of the valve body (1) and is linked to the gate (4), and a valve seat (9) is installed on the inner wall of the valve body (1) at a position corresponding to both sides of the gate (4) for forming a sealing fit with the gate (4) when the valve is closed; characterized in that: The gate (4) includes a gate frame (10), a wedge block (11), an adjusting ball (12), and two gate bodies (13). The upper end of the wedge block (11) is provided with an inverted T-shaped groove (14), and a valve stem nut (15) is provided in the inverted T-shaped groove (14). The lower end of the valve stem (3) extends into the inverted T-shaped groove (14) and is threadedly engaged with the valve stem nut (15). The gate frame (10) is provided with a guide channel (16), and the two gate bodies (13) are symmetrically arranged on both sides of the gate frame (10). The gate body (13) is provided with a guide body (17) that forms a sliding engagement with the guide channel (16). The guide body (17) is provided with a guide slope (18) that engages with the corresponding side of the wedge block (11). The gate frame (10) is also provided with multiple limiting members (19) for limiting the sliding stroke of the gate body (13).

2. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: The wedge block (11) includes two symmetrically arranged semi-wedges (20), and a hemispherical groove (21) is provided on the opposite side of the two semi-wedges (20). The left and right parts of the adjusting ball (12) are respectively arranged in the corresponding hemispherical groove (21). The valve stem nut (15) is vertically movable in the inverted T-shaped groove (14) under the drive of the valve stem (3). The valve stem (3) is also provided with a limiting step (22) on its outer periphery. A cup-shaped disc spring (23) is sandwiched between the limiting step (22) and the gate frame (10).

3. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: The limiting component (19) includes a limiting rod (24) passing through the gate frame (10) and limiting nuts (25) threaded to both ends of the limiting rod (24). The outer periphery of the gate body (13) is provided with a limiting flange (26), which is movably disposed between the gate frame (10) and the limiting nut (25).

4. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: The inner wall of the valve body (1) is provided with a mounting groove (27) for mounting the valve seat (9) on both sides of the gate plate (4). The mounting groove (27) is provided with a first bellows assembly (28). One end of the first bellows assembly (28) is welded to the inner end of the mounting groove (27), and the other end of the first bellows assembly (28) is welded to the valve seat (9). A lip ring (29) for forming a sealing fit with the inner surface of the mounting groove (27) is also installed on the outer circular surface of the valve seat (9).

5. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: The valve stem (3) includes an upper valve stem (30), an upper heat insulation sleeve head (31), a heat insulation sleeve (32), a lower heat insulation sleeve head (33), and a lower valve stem (34). The upper heat insulation sleeve head (31) and the lower heat insulation sleeve head (33) are respectively threaded to the upper and lower ends of the heat insulation sleeve (32) and welded to be fixed. The heat insulation sleeve (32) is equipped with multiple vacuum check valves (35) that only allow the medium inside the heat insulation sleeve (32) to be discharged outward. The upper heat insulation sleeve head (31), the heat insulation sleeve (32), and the lower valve stem (34) are all connected to the heat insulation sleeve (32). The outer diameter of the lower heat insulation sleeve head (33) is smaller than the inner diameter of the lower shaft hole (8). The outer circumference of the upper heat insulation sleeve head (31) and the lower heat insulation sleeve head (33) are respectively equipped with an upper guide ring (36) and a lower guide ring (37) that fit against the inner wall of the lower shaft hole (8). The upper end of the upper heat insulation sleeve head (31) is threaded with the lower end of the upper valve stem (30) and then fixed by the upper shaft pin (38). The lower end of the lower heat insulation sleeve head (33) is threaded with the upper end of the lower valve stem (34) and then fixed by the lower shaft pin (39).

6. The ultra-low temperature high-performance self-compensating gate valve according to claim 5, characterized in that: It also includes a packing assembly (40) and a second bellows assembly (41). The packing assembly (40) includes a packing pressure plate (42), a packing sleeve (43), and a sealing packing (44) which are sequentially fitted around the outer periphery of the upper valve stem (30) from top to bottom. The bracket (5) is provided with a sealing groove (45) at the position corresponding to the upper end of the upper shaft hole (7). The packing pressure plate (42) is connected to the valve cover (2) by a snap bolt (46). The packing pressure plate (42) acts on the packing sleeve (43) so that the packing sleeve (43) presses the sealing packing (44) into the sealing groove (45). The second bellows assembly (41) is fitted around the outer periphery of the upper valve stem (30). The upper end of the second bellows assembly (41) is sandwiched between the bracket (5) and the valve cover (2). The lower end of the second bellows assembly (41) is welded to the outer periphery of the upper valve stem (30).

7. The ultra-low temperature high-performance self-compensating gate valve according to claim 6, characterized in that: It also includes a steam circulation sleeve (47), and the inner end of the sealing groove (45) is provided with an installation cavity (48). The outer wall of the bracket (5) is provided with a steam inlet (49) and a steam outlet (50) that communicate with the installation cavity (48). The steam circulation sleeve (47) is set in the installation cavity (48), the upper end of the steam circulation sleeve (47) extends into the sealing groove (45), and a sealing flange (51) is provided on the outer periphery of the upper end of the steam circulation sleeve (47). The lower end of the sealing flange (51) and the inner end of the sealing groove (45) are connected by a steam inlet (49) and a steam outlet (50). A sealing gasket (52) is sandwiched between the lower end of the circulation sleeve (47) and the inner end of the mounting cavity (48). The outer periphery of the steam circulation sleeve (47) is provided with a spirally distributed air inlet channel (53) and a return channel (54). The air inlet channel (53) and the return channel (54) are staggered. The upper end of the air inlet channel (53) and the upper end of the return channel (54) are connected to the steam inlet (49) and the steam outlet (50) respectively. The lower end of the air inlet channel (53) and the lower end of the return channel (54) are connected together.

8. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: The valve body (1) and valve cover (2) are also covered with a heat insulation sleeve (55), and the heat insulation sleeve (55) is filled with a pipe insulation layer (56); the valve cover (2) is also vertically movable with an isolation drip plate (57), and the upper end of the heat insulation sleeve (55) is welded with an isolation drip plate lower connecting sleeve (78). The isolation drip plate (57) and the isolation drip plate lower connecting sleeve (78) are connected together by an isolation drip plate telescopic sleeve (58).

9. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: A self-grinding assembly (59) is also provided between the valve stem (3) and the valve cover (2). The self-grinding assembly (59) includes a guide sleeve (60), a grinding sleeve (61), a drive ball (62), a limiting plug (63), and two bearings (64). The guide sleeve (60) is installed inside the valve cover (2), and the inner diameter of the guide sleeve (60) is approximately equal to the inner diameter of the lower shaft hole (8). The grinding sleeve (61) is located between the valve stem (3) and the guide sleeve (60). Multiple scraping tools for the lower shaft are evenly distributed on the outer periphery of the upper end of the grinding sleeve (61). The grinding helical teeth (65) of the inner wall of the hole (8) are attached to the grinding sleeve (61) and the valve stem (3). An isolation gap (66) is provided between the grinding sleeve (61) and the valve stem (3). A positioning groove (67) is opened at the upper and lower ends of the inner wall of the grinding sleeve (61). The outer ring of the bearing (64) is embedded in the corresponding positioning groove (67). A retaining ring (68) is also snapped on the outer circumference of the valve stem (3) at the upper and lower positions of the two bearings (64). The retaining ring (68) abuts against the inner ring end of the corresponding bearing (64). The grinding sleeve (61) has a grinding helical teeth (65) of the inner wall of the hole (8). A spiral guide groove (69) is vertically formed on the outer circular surface. A fixing hole (70) corresponding to the spiral guide groove (69) is formed on the side wall of the guide sleeve (60). Half of the driving ball (62) is set in the spiral guide groove (69) and the other half is set in the fixing hole (70). The limiting plug (63) is threaded to the outer end of the fixing hole (70) to limit the driving ball (62). An annular groove (71) is also provided on the inner wall of the guide sleeve (60). Multiple inclined downward extending grooves are provided in the annular groove (71). The material discharge hole (72) extends through to the outer wall of the guide sleeve (60); the grinding sleeve (61) includes a movable body (73) and a grinding head (74) disposed on the upper end of the movable body (73), the grinding helical teeth (65) are disposed on the grinding head (74), the lower end of the grinding head (74) is provided with an annular connecting part (75), the upper end of the movable body (73) is provided with an annular connecting groove (76), the annular connecting part (75) and the annular connecting groove (76) fit together and are fixed together by a plurality of circumferentially distributed connecting screws (77).

10. The ultra-low temperature high-performance self-compensating gate valve according to claim 1, characterized in that: The valve cover (2) and valve body (1) are made of high-manganese austenitic alloy structural steel.

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