High pressure ultra-low temperature ball valve

Abstract

The application belongs to the field of hydraulic valves, and particularly relates to a high-pressure ultralow-temperature ball valve, which comprises a valve body and a valve cover installed on the upper end of the valve body, a medium channel and a valve cavity are respectively formed in the valve body, the medium channel and the valve cavity are in communication with each other, and a valve core assembly is installed in the valve cavity; a first matching surface and a second matching surface perpendicular to the axis of the medium channel are respectively arranged in the valve cavity; wherein the valve core assembly comprises a ball, a valve seat sleeve assembly, a valve seat support assembly and an adjusting assembly, the adjusting assembly is in operable contact with the first matching surface, and the right side of the valve seat support assembly is in sealing contact with the second matching surface. The high-pressure ultralow-temperature ball valve can meet the requirements of sealing performance, safety and service life under the conditions of ultralow temperature and high pressure.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic valves, and specifically relates to a high-pressure cryogenic ball valve. Background Technology

[0002] In the processes of LNG (liquefied natural gas) preparation, storage, transportation, receiving terminals, and regasification, ball valves used to shut off pipelines must meet requirements for sealing performance, safety, and service life under ultra-low temperature and high pressure conditions of -162℃ (design temperature is -196℃). However, at -196℃, the valve body made of metallic materials undergoes an austenitic phase transformation and cold shrinkage deformation, easily resulting in irregular and uneven reduction in valve body dimensions. Furthermore, the valve seat made of non-metallic materials also undergoes irregular cold shrinkage deformation, severely affecting the sealing performance of the ball valve. Therefore, ball valve structures and materials designed for room temperature cannot meet the requirements for use under ultra-low temperature and high pressure conditions. On the other hand, existing ball valve designs also cannot achieve online disassembly and maintenance, reducing the service life of the ball valve. Summary of the Invention

[0003] To address the problems existing in the prior art, the purpose of this invention is to provide a high-pressure cryogenic ball valve that can meet the requirements of sealing performance, safety, and service life under cryogenic and high-pressure conditions.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] A high-pressure cryogenic ball valve includes an integrally formed valve body and a valve cover installed on the upper end of the valve body. The valve body has a medium channel and a valve cavity respectively, the medium channel and the valve cavity are interconnected, a valve core assembly is installed in the valve cavity, and a valve stem is installed inside the valve cover. One end of the valve stem is drivenly connected to the valve core assembly.

[0006] The valve cavity is provided with a first mating surface and a second mating surface perpendicular to the axis of the medium channel, and a third mating surface perpendicular to the first mating surface or the second mating surface.

[0007] The valve core assembly includes a ball, a valve seat sleeve assembly, a valve seat support assembly, and an adjusting assembly. The valve seat sleeve assembly and the valve seat support assembly cooperate to form a cavity, and the ball is disposed in the cavity. The bottom of the valve seat sleeve assembly is in contact with and positioned against the third mating surface. The adjusting assembly is disposed on the left side of the valve seat sleeve assembly and is operably in contact with the first mating surface. The right side of the valve seat sleeve assembly is in sealing contact with the ball. The left side of the valve seat support assembly is in sealing contact with the ball, and the right side of the valve seat support assembly is in sealing contact with the second mating surface.

[0008] Preferably, the adjusting assembly includes a cam bolt, a cam washer, and a butterfly spring; the butterfly spring and the cam washer are sequentially sleeved on the outer periphery of the valve seat sleeve assembly, one end of the butterfly spring contacts the first mating surface, and the other end contacts the cam washer; the cam bolt is drivenly engaged with the valve seat sleeve assembly and drivenly connected to the cam washer, rotating the cam bolt can drive the cam washer to move to compress the butterfly spring, thereby adjusting the sealing preload of the valve core assembly.

[0009] Preferably, the cam bolt includes a cam portion and a threaded portion, the cam portion being drivenly connected to the cam washer, and the threaded portion being drivenly engaged with the valve seat sleeve assembly.

[0010] Preferably, the lengths of the cam portion and the threaded portion are greater than the outer diameter of the cam washer, so as to apply a uniform force to the cam washer.

[0011] Preferably, the valve seat sleeve assembly includes a valve seat sleeve body and a first valve seat. The valve seat sleeve body has a cavity for mounting the ball inside. The first valve seat is disposed inside the valve seat sleeve body. The first valve seat is in sealing contact with the ball. There is a first gap between the valve seat sleeve body and the first mating surface.

[0012] Preferably, two threaded grooves are symmetrically arranged on the valve seat sleeve body, the threaded grooves extending from the top of the valve seat sleeve body to the bottom of the valve seat sleeve body, and the threaded grooves are in drive engagement with the threaded portion of the cam bolt.

[0013] Preferably, the valve seat support assembly includes a valve seat support body, a second valve seat, and a sealing gasket; the valve seat support body is inserted into the cavity opened inside the valve seat sleeve body to form the cavity for mounting the ball; the second valve seat is provided on one side of the valve seat support body, and the second valve seat is in sealing contact with the ball; the sealing gasket is provided on the side away from the second valve seat, and the sealing gasket is in sealing contact with the second mating surface.

[0014] Preferably, the lower end of the valve stem is provided with a shoulder, and the shoulder is rotatably connected to the valve cover via a thrust bearing; a first channel is formed along the axial direction of the valve stem at the center of the valve stem, and a second channel is formed along the radial direction of the valve stem; a second gap exists between the outer circumferential surface of the valve stem and the valve cover; one end of the second channel communicates with the first channel, and the other end of the second channel communicates with the second gap; a third gap exists at the end of the valve stem connected to the ball; the first channel communicates with the medium channel at the upstream end of the valve body via the third gap, the cavity formed between the valve body and the valve cover, and the first gap.

[0015] Preferably, a valve stem sealing assembly is provided between the valve stem and the valve cover. The valve stem sealing assembly includes a first combined packing, a packing spacer ring, a second combined packing, a first gasket, a packing gasket ring, a second gasket, a second lip seal ring, and a retaining ring arranged in sequence. The retaining ring abuts against the boss of the valve cover. A packing pressure ring, a packing gland, and an elastic block are arranged in sequence at the upper end of the first combined packing. The elastic force of the elastic block can automatically compensate for the sealing preload of the valve stem sealing assembly.

[0016] Preferably, a first antistatic component is provided radially along the shoulder of the valve stem, and a second antistatic component is provided radially along the end of the valve stem where it is connected to the ball; the first antistatic component and the second antistatic component are spaced 90° apart in the circumferential direction.

[0017] Compared with the prior art, the high-pressure cryogenic ball valve provided by the present invention has the following beneficial technical effects:

[0018] 1. In this invention, the valve body is integrally formed, and the internal valve cavity has a first mating surface and a second mating surface perpendicular to the axis of the medium channel. One side of the valve core assembly is operably in contact with the first mating surface, and the other side is in sealing contact with the second mating surface. In the above configuration, by changing the conventional internal and external shaft hole seals to a planar seal, and by using an adjusting component to provide initial sealing preload and automatically compensate for wear of the valve core assembly, the problem of decreased sealing performance caused by uneven and irregular deformation between the valve body and the valve seat support assembly, and between the ball and the valve seat sleeve assembly and the valve seat support assembly, caused by factors such as austenitic phase transformation of metal materials and valve cold shrinkage deformation at ultra-low temperatures, is solved, thereby improving the sealing performance of the ball valve in the closed state.

[0019] Meanwhile, when disassembling and assembling this ball valve, simply remove the valve cover and take the valve core assembly out of the valve body from directly above, or install the valve core assembly inside the valve body. The installation and disassembly are simple. At the same time, the sealing preload of the valve core assembly can be adjusted by operating the adjustment component during disassembly and assembly, which facilitates online disassembly, assembly and maintenance of the ball valve and improves the service life of the ball valve.

[0020] 2. In this invention, the cam bolt includes a cam portion and a threaded portion. The cam portion abuts against the cam washer, and the threaded portion engages with the threaded groove on the sleeve body, allowing for simple and convenient adjustment of the initial sealing preload of the valve core assembly. During long-term use of the ball valve, if the first and / or second valve seats wear, the butterfly spring automatically compensates for the wear, ensuring good sealing performance. When further wear of the first and / or second valve seats prevents the butterfly spring from providing further sealing preload, simply remove the valve cover and locking plate, then rotate the cam bolt to move the cam washer and compress the butterfly spring. The butterfly spring then provides the necessary preload for sealing the valve core assembly again, improving the convenience of online disassembly and maintenance of the ball valve while also extending its service life.

[0021] Secondly, by setting the length of the cam part and the threaded part to be greater than the outer diameter of the cam washer, the cam part can apply a uniform force to the cam washer from top to bottom, so that the disc spring can provide a stable sealing preload.

[0022] Furthermore, setting the arc length of the thread groove cross-section to be greater than the arc length of the threaded section cross-section ensures a stable transmission connection between the cam bolt and the sleeve body, prevents the cam bolt from falling out of the thread groove, and improves the reliability of the ball valve during use.

[0023] The locking plate prevents unnecessary rotation of the cam bolt during use, thereby locking the cam bolt in the predetermined position of the sleeve body. This ensures stable contact between the cam bolt and the cam washer, allowing the disc spring to provide a stable sealing preload and improving the reliability of the ball valve during use.

[0024] 3. When a medium is present in the cavity formed between the valve body and the valve cover, the medium pressure will push the valve stem upward. The shoulder of the valve stem pushes the thrust bearing upward, and the thrust bearing contacts the valve cover, creating a sealed space in the second gap. When the gaseous medium in the second gap liquefies due to temperature changes and then vaporizes again from the liquid medium, the pressure in the second gap increases significantly. In this invention, by providing a first channel and a second channel within the valve stem, the gaseous medium in the second gap is guided through the first channel and the third gap to the cavity formed between the valve body and the valve cover, or further guided through the first gap to the medium channel at the upstream end of the valve body, thereby preventing overpressure in the second gap and ensuring the safety of the ball valve.

[0025] 4. In this invention, the valve stem seal employs a multi-layer sealing design. The first layer of sealing uses a lip seal ring, capable of withstanding ultra-low temperatures. The second layer of sealing uses two sets of combined packing arranged sequentially, and utilizes elastic blocks to automatically compensate for the sealing preload of the valve stem sealing assembly. When the combined packing wears down, it can automatically compensate. This ensures that the valve stem maintains good sealing performance even under ultra-low temperatures and alternating ambient temperatures for extended periods. Since LNG is a flammable and explosive medium, the ball valve must be designed with a corresponding fire-resistant structure to prevent external leakage in the event of a fire. In this invention, the multi-layer sealing structure between the valve cover and valve body, and between the valve stem and valve cover, meets the requirement of safe, leak-free operation in the event of a fire.

[0026] 5. During the rotation of the ball valve, friction between the ball and the plastic valve seat, and friction between the valve stem and the packing, bearings, etc., generate static electricity. Accumulated static electricity may generate sparks, which could ignite the medium and cause a safety accident. In this invention, a static electricity guiding structure is designed between the ball and the valve stem, and between the valve stem and the valve cover, to conduct the generated static electricity to the ground, preventing static electricity accumulation and improving the safety of the ball valve. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the high-pressure cryogenic ball valve of the present invention;

[0028] Figure 2 This is a partial schematic diagram of the valve body of the present invention;

[0029] Figure 3 This is a partial schematic diagram of the valve stem sealing assembly of the present invention;

[0030] Figure 4 This is a schematic diagram of the valve core assembly of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of the valve seat support body of the present invention;

[0032] Figure 6 This is a cross-sectional view of the valve seat sleeve body of the present invention;

[0033] Figure 7 This is a top view of the valve seat sleeve body of the present invention;

[0034] Figure 8 This is a schematic diagram of the cam bolt of the present invention;

[0035] Figure 9 This is a schematic diagram of the locking plate of the present invention.

[0036] The meanings of the symbols marked in the figure are as follows:

[0037] 1. Valve body; 2. Valve stem; 3. Valve core assembly; 4. Valve cover; 5. Handle; 6. Valve stem sealing assembly; 7. Drip tray;

[0038] 11. First mating surface; 12. Second mating surface; 13. Third mating surface;

[0039] 21. First channel; 22. Second channel; 23. Second gap; 24. First antistatic component; 25. Second antistatic component; 26. Third gap; 27. First lip seal; 28. Metal ring gasket; 29. ​​Shoulder;

[0040] 31. Ball; 32. Valve seat sleeve assembly; 33. Valve seat support assembly; 34. Cam bolt; 35. Cam washer; 36. Disc spring; 37. Locking plate; 38. First clearance;

[0041] 321. Sleeve body; 322. First column; 323. Second column; 324. Chamber; 325. Through hole; 326. First fluid passage; 327. First mounting groove; 328. First valve seat; 329. Threaded groove;

[0042] 331. Protrusion; 332. Support body; 333. Second mounting groove; 334. Third mounting groove; 335. Second fluid passage; 336. Sealing gasket; 337. Second valve seat;

[0043] 341. Cam portion; 342. Threaded portion; 371. Locking hole;

[0044] 51. Packing ring; 52. Packing gland; 53. Elastic block;

[0045] 61. Packing spacer ring; 62. First packing combination; 63. Second packing combination; 64. Second lip seal ring; 65. Packing gasket ring; 66. First gasket; 67. Second gasket; 68. Retaining ring. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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.

[0047] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the embodiments of the present invention can be combined with each other.

[0049] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0051] See appendix Figure 1 - Appendix Figure 9 As shown, this invention provides a high-pressure cryogenic ball valve, comprising an integrally formed valve body 1 and a valve cover 4 mounted on the upper end of the valve body 1. The valve body 1 has a medium channel and a valve cavity respectively, which are interconnected. A valve core assembly 3 is installed in the valve cavity. A valve stem 2 is installed inside the valve cover 4. One end of the valve stem 2 is driveably connected to the valve core assembly 3, and the other end of the valve stem 2 is driveably connected to a handle 5. A valve stem sealing assembly 6 is provided between the valve stem 2 and the valve cover 4, and a drip tray 7 is provided on the outer circumferential surface of the valve cover 4.

[0052] The valve cavity is provided with a first mating surface 11 and a second mating surface 12 that are perpendicular to the axis of the medium channel, and a third mating surface 13 that is perpendicular to the first mating surface 11 or the second mating surface 12.

[0053] The valve core assembly 3 includes a ball 31, a valve seat sleeve assembly 32, a valve seat support assembly 33, and an adjusting assembly. The valve seat sleeve assembly 32 and the valve seat support assembly 33 cooperate to form a cavity, in which the ball 31 is disposed. The bottom of the valve seat sleeve assembly 32 contacts and is positioned in contact with the third mating surface 13. An adjusting assembly is disposed on the left side of the valve seat sleeve assembly 32, which is operably in contact with the first mating surface 11. The sealing preload of the valve core assembly 3 is adjusted by operating the adjusting assembly. The right side of the valve seat sleeve assembly 32 is in sealing contact with the ball 31, the left side of the valve seat support assembly 33 is in sealing contact with the ball 31, and the right side of the valve seat support assembly 33 is in sealing contact with the second mating surface 12.

[0054] Preferably, the adjusting assembly includes a cam bolt 34, a cam washer 35, and a butterfly spring 36. The butterfly spring 36 and the cam washer 35 are sequentially sleeved on the outer periphery of the valve seat sleeve assembly 32. One end of the butterfly spring 36 contacts the first mating surface 11, and the other end contacts the cam washer 35. The cam bolt 34 is driven to engage with the valve seat sleeve assembly 32 and is driven to connect with the cam washer 35. Rotating the cam bolt 34 can drive the cam washer 35 to move to compress the butterfly spring 36, thereby adjusting the sealing preload of the valve core assembly 3. This provides an initial sealing preload for the valve core assembly 3 and automatically compensates for the wear of the valve core assembly 3 during use, ensuring the sealing performance of the ball valve in the closed state.

[0055] In the above embodiment, the valve body is integrally formed, and the internal valve cavity has a first mating surface and a second mating surface perpendicular to the axis of the medium channel. One side of the valve core assembly is operably in contact with the first mating surface, and the other side is in sealing contact with the second mating surface. In the above configuration, by changing the conventional internal and external shaft hole seals to a planar seal, and by using an adjusting component to provide initial sealing preload and automatically compensate for the wear of the valve core assembly, the problem of decreased sealing performance caused by uneven and irregular deformation between the valve body and the valve seat support assembly, and between the ball and the valve seat sleeve assembly and the valve seat support assembly, caused by factors such as the austenitic phase transformation of the metal material and the cold shrinkage deformation of the valve at ultra-low temperatures, is solved, thereby improving the sealing performance of the ball valve in the closed state.

[0056] Meanwhile, when disassembling and assembling this ball valve, simply remove the valve cover and take the valve core assembly out of the valve body from directly above, or install the valve core assembly inside the valve body. The installation and disassembly are simple. At the same time, the sealing preload of the valve core assembly can be adjusted by operating the adjustment component during disassembly and assembly, which facilitates online disassembly, assembly and maintenance of the ball valve and improves the service life of the ball valve.

[0057] Preferably, the adjusting assembly further includes a locking plate 37, which cooperates with the cam bolt 34 to lock the cam bolt 34 at a predetermined position in the valve seat sleeve assembly 32.

[0058] Preferably, the cam bolt 34 includes a cam portion 341 and a threaded portion 342. The cam portion 341 can be drivenly connected to the cam washer 35 or directly abut against it, and the threaded portion 342 is drivenly engaged with the valve seat sleeve assembly 32. The lengths of the cam portion 341 and the threaded portion 342 are greater than the outer diameter of the cam washer 35, so as to apply a uniform force to the cam washer 35.

[0059] Preferably, the valve seat sleeve assembly 32 includes a valve seat sleeve body and a first valve seat 328. The valve seat sleeve body includes a sleeve body 321 and a first column 322 and a second column 323 extending along one side of the sleeve body 321. The diameter of the second column 323 is smaller than the diameter of the first column 322. A cam washer 35 is fitted onto the outer circumferential surface of the first column 322, and a disc spring 36 is fitted onto the outer circumferential surface of the second column 323. When the valve core assembly 3 is installed inside the valve body 1, a first gap 38 exists between the end face of the second column 323 and the first mating surface 11.

[0060] Preferably, a first fluid channel 326 is provided at the second column 323 along the axial direction of the second column 323; a through hole 325 is provided at the sleeve body 321 along the axial direction perpendicular to the second column 323, the diameter of the through hole 325 being larger than the diameter of the valve stem 2; a chamber 324 for installing the ball 31 is provided inside the sleeve body 321, and both the first fluid channel 326 and the through hole 325 are connected to the chamber 324.

[0061] Preferably, an annular first mounting groove 327 is provided inside the sleeve body 321, and a first valve seat 328 is provided in the first mounting groove 327. The first valve seat 328 is in sealing contact with the ball 31, wherein the first valve seat 328 is made of PCTFE plastic.

[0062] Preferably, two threaded grooves 329 are provided on the sleeve body 321 along the axial direction perpendicular to the second column 323. The threaded grooves 329 extend from the top of the sleeve body 321 to the bottom of the sleeve body 321. The two threaded grooves 329 are symmetrically arranged about the axial direction of the second column 323. The threaded grooves 329 are in transmission engagement with the threaded portion 342 of the cam bolt 34. The arc length of the cross-section of the threaded groove 329 is greater than the arc length of the cross-section of the threaded portion 342 to ensure a stable transmission connection between the cam bolt 34 and the sleeve body 321.

[0063] Preferably, the locking plate 37 is symmetrically provided with locking holes 371 that are adapted to the cam bolts 34. The locking holes 371 can prevent the cam bolts 34 from rotating, thereby locking the cam bolts 34 in a predetermined position on the sleeve body 321. In use, the cam bolts 34 are first rotated to the predetermined position on the sleeve body 321, and then the locking holes 371 on the locking plate 37 are respectively fitted onto the ends of the two cam bolts 34. The locking holes 371 are used to prevent the cam bolts 34 from rotating further, thereby locking the cam bolts 34 in the predetermined position on the sleeve body 321.

[0064] Preferably, the valve seat support assembly 33 includes a valve seat support body, a second valve seat 337 and a sealing gasket 336. The valve seat support body includes a support body 332 and a protrusion 331 extending along one side of the support body 332. The protrusion 331 is inserted into a cavity 324 opened inside the sleeve body 321 to form a cavity for mounting the ball 31.

[0065] Preferably, an annular second mounting groove 333 is further formed inside the valve seat support body, and a second valve seat 337 is disposed in the second mounting groove 333. The second valve seat 337 is in sealing contact with the ball 31, and the second valve seat 337 is made of PCTFE plastic. An annular third mounting groove 334 is formed on the side away from the second mounting groove 333, and a sealing gasket 336 is disposed in the third mounting groove 334. The sealing gasket 336 is in sealing contact with the second mating surface 12.

[0066] Preferably, a second fluid channel 335 is provided inside the valve seat support body, wherein the first fluid channel 326, the second fluid channel 335, the medium channel provided inside the valve body 1 and the medium channel provided inside the ball 31 can communicate with each other.

[0067] In the above embodiment, the cam bolt includes a cam portion and a threaded portion. The cam portion abuts against the cam washer, and the threaded portion engages with the threaded groove on the sleeve body, allowing for simple and convenient adjustment of the initial sealing preload of the valve core assembly. During long-term use of the ball valve, if the first and / or second valve seats wear, the butterfly spring automatically compensates for the wear, ensuring good sealing performance. When further wear of the first and / or second valve seats prevents the butterfly spring from providing further sealing preload, simply remove the valve cover and locking plate, then rotate the cam bolt to move the cam washer and compress the butterfly spring. The butterfly spring then provides the necessary preload for sealing the valve core assembly again, improving the convenience of online disassembly and maintenance of the ball valve while also extending its service life.

[0068] Secondly, by setting the length of the cam part and the threaded part to be greater than the outer diameter of the cam washer, the cam part can apply a uniform force to the cam washer from top to bottom, so that the disc spring can provide a stable sealing preload.

[0069] Furthermore, setting the arc length of the thread groove cross-section to be greater than the arc length of the threaded section cross-section ensures a stable transmission connection between the cam bolt and the sleeve body, prevents the cam bolt from falling out of the thread groove, and improves the reliability of the ball valve during use.

[0070] The locking plate prevents unnecessary rotation of the cam bolt during use, thereby locking the cam bolt in the predetermined position of the sleeve body. This ensures stable contact between the cam bolt and the cam washer, allowing the disc spring to provide a stable sealing preload and improving the reliability of the ball valve during use.

[0071] Preferably, the lower end of the valve stem 2 is provided with a shoulder 29, and the shoulder 29 is rotatably connected to the valve cover 4 via a thrust bearing. A first channel 21 is formed along the axial direction of the valve stem 2 at its center, and a second channel 22 is formed along the radial direction of the valve stem 2. A second gap 23 is provided between the outer circumferential surface of the valve stem 2 and the valve cover 4. One end of the second channel 22 communicates with the first channel 21, and the other end of the second channel 22 communicates with the second gap 23. The end of the valve stem 2 connected to the ball 31 has a third gap 26. The first channel 21 communicates with the medium channel at the upstream end of the valve body 1 via the third gap 26, the cavity formed between the valve body 1 and the valve cover 4, and the first gap 38.

[0072] When a medium is present in the cavity formed between the valve body and the valve cover, the medium pressure pushes the valve stem upward. The shoulder of the valve stem pushes the thrust bearing upward, and the thrust bearing contacts the valve cover, creating a sealed space in the second gap. When the gaseous medium in the second gap liquefies due to temperature changes and then vaporizes again, the pressure in the second gap increases significantly. In the above embodiment, by providing a first channel and a second channel within the valve stem, the gaseous medium in the second gap is guided through the first channel and the third gap to the cavity formed between the valve body and the valve cover, or further guided through the first gap to the medium channel at the upstream end of the valve body, thereby preventing overpressure in the second gap and ensuring the safety of the ball valve.

[0073] Preferably, a first lip seal 27 and a metal ring gasket 28 are sequentially arranged between the valve body 1 and the valve cover 4. The first lip seal 27 is located on the inner side to form a primary seal, and the metal ring gasket 28 is located on the outer side to form a secondary seal.

[0074] Preferably, the valve stem sealing assembly 6 includes a first combined packing 62, a packing spacer 61, a second combined packing 63, a first gasket 66, a packing gasket ring 65, a second gasket 67, a second lip seal ring 64, and a retaining ring 68 arranged in sequence. The retaining ring 68 abuts against the boss of the valve cover 4. The upper end of the first combined packing 62 is provided with a packing pressure ring 51, a packing pressure cap 52, and an elastic block 53 in sequence. The elastic force provided by the elastic block 53 can automatically compensate for the sealing preload of the valve stem sealing assembly 6.

[0075] The valve stem seal employs a multi-layer sealing design. The first layer uses a lip seal ring capable of withstanding ultra-low temperatures. The second layer uses two sets of sequentially arranged packing, with an elastic block automatically compensating for the sealing preload of the valve stem sealing assembly. This automatic compensation ensures good sealing performance of the valve stem under ultra-low and alternating ambient temperatures for extended periods. Since LNG is a flammable and explosive medium, the ball valve must be designed with a corresponding fire-resistant structure to prevent external leakage in the event of a fire. In the above embodiment, the multi-layer sealing structure between the valve cover and valve body, and between the valve stem and valve cover, meets the requirement of safe, leak-free operation in the event of a fire.

[0076] Preferably, a first antistatic component 24 is provided radially along the valve stem 2 at the shoulder 29 of the valve stem 2, and a second antistatic component 25 is provided radially along the valve stem 2 at the end of the valve stem 2 that is connected to the ball 31; the first antistatic component 24 and the second antistatic component 25 are spaced 90° apart in the circumferential direction.

[0077] During the rotation of the ball valve, friction between the ball and the plastic valve seat, and friction between the valve stem and the packing, bearings, etc., generates static electricity. Accumulated static electricity may produce sparks, potentially igniting the medium and causing a safety accident. In the above embodiment, a static electricity guiding structure is designed between the ball and the valve stem, and between the valve stem and the valve cover, to conduct the generated static electricity to the ground, preventing static electricity accumulation and improving the safety of the ball valve.

[0078] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A high-pressure cryogenic ball valve, characterized in that: The valve includes an integrally formed valve body and a valve cover installed on the upper end of the valve body. The valve body has a medium channel and a valve cavity respectively. The medium channel and the valve cavity are interconnected. A valve core assembly is installed in the valve cavity. A valve stem is installed inside the valve cover. One end of the valve stem is drivenly connected to the valve core assembly. The valve cavity is provided with a first mating surface and a second mating surface perpendicular to the axis of the medium channel, and a third mating surface perpendicular to the first mating surface or the second mating surface. The valve core assembly includes a ball, a valve seat sleeve assembly, a valve seat support assembly, and an adjusting assembly. The valve seat sleeve assembly and the valve seat support assembly cooperate to form a cavity, and the ball is disposed in the cavity. The bottom of the valve seat sleeve assembly is in contact with and positioned against the third mating surface. The adjusting assembly is disposed on the left side of the valve seat sleeve assembly and is operably in contact with the first mating surface. The right side of the valve seat sleeve assembly is in sealing contact with the ball. The left side of the valve seat support assembly is in sealing contact with the ball, and the right side of the valve seat support assembly is in sealing contact with the second mating surface. The adjusting assembly includes a cam bolt, a cam washer, and a butterfly spring. The butterfly spring and the cam washer are sequentially sleeved on the outer periphery of the valve seat sleeve assembly. One end of the butterfly spring contacts the first mating surface, and the other end contacts the cam washer. The cam bolt is driven to engage with the valve seat sleeve assembly and is driven to connect with the cam washer. Rotating the cam bolt can drive the cam washer to move to compress the butterfly spring, thereby adjusting the sealing preload of the valve core assembly. The cam bolt includes a cam portion and a threaded portion. The cam portion is drivenly connected to the cam washer, and the threaded portion is drivenly engaged with the valve seat sleeve assembly. The lengths of the cam portion and the threaded portion are greater than the outer diameter of the cam washer, so as to apply a uniform force to the cam washer.

2. The high-pressure cryogenic ball valve as described in claim 1, characterized in that: The valve seat sleeve assembly includes a valve seat sleeve body and a first valve seat. The valve seat sleeve body has a cavity for mounting the ball. The first valve seat is disposed inside the valve seat sleeve body and is in sealing contact with the ball. There is a first gap between the valve seat sleeve body and the first mating surface.

3. The high-pressure cryogenic ball valve as described in claim 2, characterized in that: Two threaded grooves are symmetrically arranged on the valve seat sleeve body. The threaded grooves extend from the top of the valve seat sleeve body to the bottom of the valve seat sleeve body. The threaded grooves are in drive engagement with the threaded portion of the cam bolt.

4. The high-pressure cryogenic ball valve as described in claim 3, characterized in that: The valve seat support assembly includes a valve seat support body, a second valve seat, and a sealing gasket; the valve seat support body is inserted into the cavity opened inside the valve seat sleeve body to form the cavity for mounting the ball; the second valve seat is provided on one side of the valve seat support body, and the second valve seat is in sealing contact with the ball; the sealing gasket is provided on the side away from the second valve seat, and the sealing gasket is in sealing contact with the second mating surface.

5. The high-pressure cryogenic ball valve as described in claim 4, characterized in that: The lower end of the valve stem is provided with a shoulder, which is rotatably connected to the valve cover via a thrust bearing. A first channel is formed along the axial direction of the valve stem at the center of the valve stem, and a second channel is formed along the radial direction of the valve stem. A second gap exists between the outer circumferential surface of the valve stem and the valve cover. One end of the second channel communicates with the first channel, and the other end of the second channel communicates with the second gap. The end of the valve stem connected to the ball has a third gap. The first channel communicates with the medium channel at the upstream end of the valve body via the third gap, the cavity formed between the valve body and the valve cover, and the first gap.

6. The high-pressure cryogenic ball valve as described in claim 5, characterized in that: A valve stem sealing assembly is provided between the valve stem and the valve cover. The valve stem sealing assembly includes a first combined packing, a packing spacer ring, a second combined packing, a first gasket, a packing gasket ring, a second gasket, a second lip seal ring, and a retaining ring arranged in sequence. The retaining ring abuts against the boss of the valve cover. A packing pressure ring, a packing gland, and an elastic block are arranged in sequence at the upper end of the first combined packing. The elastic force of the elastic block can automatically compensate for the sealing preload of the valve stem sealing assembly.

7. The high-pressure cryogenic ball valve as described in claim 6, characterized in that: At the shoulder of the valve stem, a first antistatic component is provided radially along the valve stem; at the end of the valve stem where it is connected to the ball, a second antistatic component is provided radially along the valve stem; the first antistatic component and the second antistatic component are spaced 90° apart in the circumferential direction.

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