Ultralow-temperature ball valve

Abstract

The ultralow-temperature ball valve comprises a valve seat, a valve element mechanism located in the valve seat and a valve rod connected with the valve element mechanism. The valve seat comprises a containing cavity, a first groove and a third groove, wherein the first groove and the third groove are communicated with the containing cavity. The bottom faces of the first groove and the third groove are conical faces inclining in the direction away from the containing cavity from the periphery to the middle. The valve element mechanism comprises a ball core located in the containing cavity and two sealing assemblies located in the first groove and the third groove and matched with the ball core for sealing, and each sealing assembly comprises a sealing base, a first sealing piece installed on the side, facing the ball core, of the sealing base and a lantern ring arranged on the outer side of the sealing base in a sleeving mode. The side, facing the bottom face of the adjacent first groove or third groove, of the lantern ring inclines in the direction away from the containing cavity from the periphery to the middle, and the inclination angle is the same as the bottom face of the adjacent first groove or third groove. And plate-shaped annular reeds are arranged between the bottom surface of the first groove and the lantern ring and between the bottom surface of the third groove and the lantern ring.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ball valves, in particular to an ultra-low temperature ball valve. BACKGROUND

[0002] The ultra-low temperature ball valve is used in fluid transmission pipeline for transmitting fluid below-150℃, and the valve needs to withstand extremely cold temperature, so the sealing safety performance of the valve is required to be extremely high. The existing sealing technology is mainly divided into two categories, which are full metal hard sealing and non-metal soft sealing. Non-metal soft sealing uses PCTFE, PTFE and other materials as sealing elements, but these non-metal sealing elements will also shrink obviously and cause poor elasticity and sealing failure during long-term use in an ultra-low temperature environment, so the existing design sets a spring to apply force to the non-metal sealing element, so that the non-metal sealing element can be effectively attached to the ball core to form a seal.

[0003] However, the scheme has the following defects: the spring needs to be provided with a relatively long accommodation space in the length direction to effectively apply the elastic force for a long time, resulting in the need to increase the design size of the ball valve. SUMMARY

[0004] In order to realize long-term effective use of the ultra-low temperature ball valve with small size, the present application provides an ultra-low temperature ball valve.

[0005] The ultra-low temperature ball valve provided by the present application adopts the following technical scheme: An ultra-low temperature ball valve, comprising a valve seat, a valve core mechanism located in the valve seat, and a valve stem connected to the valve core mechanism; The valve seat comprises an accommodation cavity, a first groove and a third groove in communication with the accommodation cavity, and the bottom surfaces of the first groove and the third groove are tapered surfaces inclined from the periphery to the middle to the direction away from the accommodation cavity, and the taper angle is 10-30 degrees; The valve core mechanism comprises a ball core located in the accommodation cavity, two groups of sealing assemblies located in the first groove and the third groove and cooperating with the ball core to seal, the sealing assembly comprises a sealing base, a first sealing element installed on the side of the sealing base facing the ball core, a sleeve ring sleeved on the outer side of the sealing base, and a second sealing element located between the sealing base and the sleeve ring, the sleeve ring is inclined from the periphery to the middle to the direction away from the accommodation cavity on the side facing the bottom surface of the adjacent first groove or third groove, and the inclination angle is the same as that of the bottom surface of the adjacent first groove or third groove, and a plate-shaped annular spring sheet is arranged between the first groove bottom surface and the sleeve ring and between the third groove bottom surface and the sleeve ring.

[0006] By adopting the technical scheme, the reed is arranged between the bottom surface of the first groove and the collar and between the bottom surface of the third groove and the collar, and the side of the bottom surface of the first groove, the bottom surface of the third groove and the collar facing the reed is a small-angle inclined surface. Therefore, when the valve core mechanism is installed in the valve seat, a force can be applied to make the reed slightly deform to the state of the same inclination angle as the side of the bottom surface of the first groove, the bottom surface of the third groove and the collar facing the reed. At this time, the deformed reed stores potential energy, the force is applied to the collar to make the second sealing element between the collar and the sealing base deform to form a sealing surface with the inner side wall of the valve seat, and the first sealing element is pressed to form a sealing surface with the ball core. And because the reed is a plate-shaped ring, it will not change the direction of the protrusion after excessive deformation like a butterfly spring, so as to shorten the effective elasticity.

[0007] Preferably, the inclination angle of the bottom surface of the first groove and the third groove is 15 degrees.

[0008] Preferably, the sealing base comprises a cylindrical barrel, a mounting seat formed at one end of the barrel facing the ball core, an arc-shaped guide surface formed at the side of the mounting seat facing the ball core, the arc-shaped guide surface being inclined from the periphery to the middle to the end away from the ball core, an annular mounting groove being formed on the arc-shaped guide surface around the barrel, and the first sealing element being embedded in the mounting groove.

[0009] By adopting the technical scheme, the arc-shaped guide surface is used to avoid the ball core, and the distance between the arc-shaped guide surface and the ball core is close at each position. When the first sealing element is arranged to cooperate with the ball core to seal, the deformable space of the fitting surface in each direction is also close, so that a more reliable sealing surface is formed.

[0010] Preferably, the first sealing element is annular, and an arc-shaped fitting surface is formed at the side of the first sealing element facing the ball core to fit the surface of the ball core.

[0011] By adopting the technical scheme, the arc-shaped fitting surface is used to cooperate with the ball core to form a large-area effective sealing surface, so that the sealing is more reliable.

[0012] Preferably, an arc-shaped extrusion surface is formed at the side of the mounting seat away from the ball core, an annular extension surface parallel to the surface of the barrel is formed at the end of the arc-shaped extrusion surface close to the barrel, and a transition surface perpendicular to the surface of the barrel is formed at the end of the annular extension surface away from the arc-shaped extrusion surface. The inner side wall of the collar and the outer side wall of the barrel are fitted, an annular avoiding groove is formed at the side of the collar facing the mounting seat, the width of the avoiding groove is equal to the width of the transition surface, and when the collar abuts against the second sealing element, a space is left between the bottom surface of the avoiding groove and the transition surface.

[0013] By adopting the above technical solution, when the first sealing element abuts against the ball core, the sealing base can no longer move towards the ball core, and at this time there is a gap between the bottom surface of the clearance groove and the transition surface. Therefore, the force applied by the spring will also drive the collar to move relative to the sealing base, so that the second sealing element located between the two arches towards the inner wall of the valve seat under the action of the arc extrusion surface to form a sealing surface.

[0014] Preferably, the second seal is annular and located between the mounting seat and the collar. The inner wall of the second seal is in contact with the annular extension surface, the outer wall of the second seal is in contact with the inner wall of the valve seat, and the other two sides of the second seal abut against the arc-shaped extrusion surface and the end face of the collar, respectively.

[0015] By adopting the above technical solution, the sidewall of the second seal is in contact with the annular extension surface, the inner sidewall of the valve seat, the arc-shaped extrusion surface and the end face of the collar, respectively. Therefore, it will be extruded and deformed with the four surfaces when subjected to force, forming an effective sealing surface.

[0016] Preferably, the outer diameter of the spring is equal to the inner diameter of the first groove and the third groove, and the inner diameter of the spring is equal to the inner diameter of the cylinder.

[0017] By adopting the above technical solution, the outer diameter of the spring is set to be equal to the inner diameter of the first and third grooves, and the inner diameter of the spring is equal to the inner diameter of the cylinder. This effectively utilizes the small radial space, allowing the spring to exert a greater restoring force. Furthermore, since the spring is plate-shaped, the space formed between the bottom surface of the first and third grooves and the collar is an oblique space. Therefore, the spring will not have an interference fit with other components during deformation.

[0018] Preferably, the valve seat has a left flow channel and a right flow channel. The bottom surface of the first groove is formed with a second groove with a diameter smaller than that of the first groove. The bottom surface of the second groove is connected to the left flow channel, and the diameter of the second groove is larger than that of the left flow channel. Two first annular grooves are formed on the inner sidewall of the second groove. The bottom surface of the third groove is formed with a fourth groove with a diameter smaller than that of the third groove. The bottom surface of the fourth groove is connected to the right flow channel, and the diameter of the fourth groove is larger than that of the right flow channel. Two second annular grooves are formed on the inner sidewall of the fourth groove. An annular third sealing element is installed in both the first annular groove and the second annular groove.

[0019] By adopting the above technical solution, a third sealing element is set in the first annular groove and the second annular groove to form a sealing surface, so that even if the second sealing element fails, an effective sealing state can still be maintained.

[0020] Preferably, the valve seat includes a left valve body, a right valve cover, and a stuffing box installed above the left valve body. A first sealing ring is provided between the left valve body and the stuffing box to form a sealing surface by compression. A sealing groove is formed on the side of the left valve body facing the right valve cover, and a second sealing ring is embedded in the sealing groove. A sealing protrusion corresponding to the sealing groove is formed on the side of the right valve cover facing the left valve body.

[0021] By adopting the above technical solution, when the left valve body and the right valve cover are connected, the sealing protrusion and the second sealing ring are squeezed to form a sealing surface.

[0022] Preferably, the spring is a plate-shaped annular ring. The outer ring of the spring facing the bottom surface of the adjacent first and third grooves has a first annular slit, and the inner ring of the spring facing the collar has a second annular slit. The depth of the first annular slit is half the thickness of the spring, and the angle of the first annular slit is equal to the inclination angle of the bottom surface of the first and third grooves. The depth of the second annular slit is half the thickness of the spring, and the angle of the second annular slit is equal to the inclination angle of the collar facing away from the mounting base.

[0023] By adopting the above technical solution, the shape of the reed is not limited to a double-sided flat plate. Even with protrusions or grooves on both sides of the reed, the purpose of this application can still be achieved. Furthermore, in the preferred embodiment described above, the first annular cut and the second annular cut on the reed have angles equal to the inclination angles of the bottom surfaces of the first and second grooves. This allows the reed to abut against the bottom surface of the first or third groove through the first annular cut and against the collar through the second annular cut during reset, resulting in surface contact and the application of force, thus reducing the influence of line contact deformation on the elastic force.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. The reed is positioned between the bottom surface of the first groove and the collar, and between the bottom surface of the third groove and the collar. Since the bottom surfaces of the first and third grooves, and the side of the collar facing the reed are all inclined at a small angle, when the valve core mechanism is installed in the valve seat, a force can be applied to deform the reed slightly to the same angle as the bottom surfaces of the first and third grooves and the side of the collar facing the reed. At this time, the reed stores potential energy after deformation, and applies a force to the collar, causing the second sealing element between the collar and the sealing base to deform, forming a sealing surface with the inner wall of the valve seat. At the same time, the first sealing element is pressed against the ball core to form a sealing surface.

[0025] 2. When the first seal comes into contact with the ball core, the sealing base can no longer move toward the ball core. At this time, there is a gap between the bottom surface of the clearance groove and the transition surface. Therefore, the force applied by the spring will also drive the collar to move relative to the sealing base, so that the second seal located between the two arches toward the inner wall of the valve seat under the action of the arc-shaped extrusion surface to form a sealing surface.

[0026] 3. The outer diameter of the spring is set to be equal to the inner diameter of the first and third grooves, and the inner diameter of the spring is equal to the inner diameter of the cylinder. This effectively utilizes the small radial space, allowing the spring to exert its maximum restoring force. Furthermore, since the spring is plate-shaped, the space formed between the bottom surfaces of the first and third grooves and the collar is an oblique space. Therefore, the spring will not experience an interference fit with other components during deformation. Attached Figure Description

[0027] Figure 1 This is a structural schematic diagram of Embodiment 1; Figure 2 This is a cross-sectional schematic diagram of Embodiment 1; Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 4 This is an enlarged view of the sealing assembly. Figure 5 This is an enlarged view of the reed portion in Embodiment 2; Figure 6 This is an enlarged view of the reed portion in Embodiment 3.

[0028] Explanation of reference numerals in the attached drawings: 1. Valve seat; 2. Valve core mechanism; 3. Valve stem; 4. Left valve body; 5. Right valve cover; 6. Stuffing gland; 7. First sealing ring; 8. Receiving cavity; 9. First groove; 10. Second groove; 11. Left flow channel; 12. First annular groove; 13. Sealing groove; 14. Second sealing ring; 15. Third groove; 16. Fourth groove; 17. Second annular groove; 18. Sealing protrusion; 19. Ball core; 20. Sealing assembly; 21. Sealing base 21. Seat; 22. First seal; 23. Collar; 24. Second seal; 25. Cylinder; 26. Mounting seat; 27. Arc-shaped guide surface; 28. Mounting groove; 29. ​​Arc-shaped mating surface; 30. Arc-shaped extrusion surface; 31. Annular extension surface; 32. Transition surface; 33. Clearance groove; 34. Spring; 35. First annular cut; 36. Second annular cut; 37. First annular protrusion; 38. Second annular protrusion; 39. Right flow channel; 40. Third seal. Detailed Implementation

[0029] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0030] This application discloses an ultra-low temperature ball valve. The terms "upper", "lower", "left" and "right" used in the embodiments are schematic representations of the relative directions of the positional relationship, and are not restrictions on the positional relationship.

[0031] Example 1: like Figure 1 and Figure 2As shown, the cryogenic ball valve includes a valve seat 1, a valve core mechanism 2 located within the valve seat 1, and a valve stem 3 connected to the valve core mechanism 2.

[0032] like Figure 1 and Figure 2 As shown, the valve seat 1 includes a left valve body 4, a right valve cover 5, and a stuffing box 6 installed above the left valve body 4. A first sealing ring 7 is provided between the left valve body 4 and the stuffing box 6 to form a sealing surface. A receiving cavity 8 is formed on the side of the left valve body 4 facing the right valve cover 5. A first groove 9 with a diameter smaller than the receiving cavity 8 is formed on the bottom surface of the receiving cavity 8. A second groove 10 with a diameter smaller than the first groove 9 is formed on the bottom surface of the first groove 9. The bottom surface of the second groove 10 is connected to the left flow channel 11 of the left valve body 4, and the diameter of the second groove 10 is larger than the diameter of the left flow channel 11. The bottom surface of the receiving cavity 8 is rounded to the side wall. The bottom surface of the first groove 9 is a conical surface that slopes from the periphery towards the center towards the left flow channel 11, with an inclination angle of 10-30 degrees, preferably 15 degrees in this embodiment. Two first annular grooves 12 are formed on the inner side wall of the second groove 10. The left valve body 4 has a sealing groove 13 formed around the receiving cavity 8 on the side facing the right valve cover 5, and a second sealing ring 14 is embedded in the sealing groove 13.

[0033] like Figure 2 and Figure 3 As shown, a third groove 15 is formed on the side of the right valve cover 5 facing the left valve body 4. A fourth groove 16 with a smaller diameter than the third groove 15 is formed on the bottom surface of the third groove 15. The bottom surface of the fourth groove 16 is connected to the right flow channel 39 of the right valve cover 5, and the diameter of the fourth groove 16 is larger than the diameter of the right flow channel 39. The bottom surface of the third groove 15 slopes from the periphery towards the center towards the right flow channel 39, forming a conical surface, and the slope angle is equal to the slope angle of the bottom surface of the first groove 9. Two second annular grooves 17 are formed on the inner wall of the fourth groove 16. A sealing protrusion 18 is formed around the third groove 15 on the side of the right valve cover 5 facing the left valve body 4. The sealing protrusion 18 is directly opposite the sealing groove 13. When the right valve cover 5 and the left valve body 4 are tightly connected by fasteners, the sealing protrusion 18 abuts against the second sealing ring 14 to form a sealing surface.

[0034] like Figures 2 to 4As shown, the valve core mechanism 2 includes a ball core 19 and sealing assemblies 20 located on the left and right sides of the ball core 19, which cooperate with and seal against the ball core 19. The sealing assembly 20 includes a sealing base 21, a first sealing element 22 installed on the side of the sealing base 21 facing the ball core 19, a collar 23 sleeved on the outside of the sealing base 21, and a second sealing element 24 located between the sealing base 21 and the collar 23. The sealing base 21 includes a cylindrical body 25 and a mounting seat 26 formed on the end of the cylindrical body 25 facing the ball core 19. An arc-shaped guide surface 27 is formed on the side of the mounting seat 26 facing the ball core 19, and the arc-shaped guide surface 27 slopes from the periphery towards the center and away from the ball core 19. An annular mounting groove 28 surrounds the cylindrical body 25 on the arc-shaped guide surface 27, and the first sealing element 22 is embedded in the mounting groove 28. The first seal 22 is annular, and the side of the first seal 22 facing the ball core 19 has an arc-shaped contact surface 29 that fits against the surface of the ball core 19. The mounting base 26 has an arc-shaped extrusion surface 30, an annular extension surface 31 located at the end of the arc-shaped extrusion surface 30 near the cylinder 25 and parallel to the surface of the cylinder 25, and a transition surface 32 located at the end of the annular extension surface 31 away from the arc-shaped extrusion surface 30 and perpendicular to the surface of the cylinder 25.

[0035] The inner wall of the collar 23 fits against the outer wall of the cylinder 25. An annular clearance groove 33 is formed on the side of the collar 23 facing the mounting base 26. The width of the clearance groove 33 is equal to the width of the transition surface 32, and a gap exists between the bottom surface of the clearance groove 33 and the transition surface 32 when the collar 23 abuts against the second seal 24. The second seal 24 is annular and located between the mounting base 26 and the collar 23. The inner wall of the second seal 24 fits against the annular extension surface 31, and the outer wall of the second seal 24 fits against the inner wall of the valve seat 1. The other two sides of the second seal 24 abut against the arc-shaped extrusion surface 30 and the end face of the collar 23, respectively. The side of the collar 23 facing away from the mounting base 26 slopes from all sides towards the center, away from the mounting base 26, and the angle of inclination is equal to the angle of inclination of the bottom surface of the first groove 9. A spring sheet 34 is provided between the bottom surface of the first groove 9 and the collar 23, and between the bottom surface of the third groove 15 and the collar 23. The spring sheet 34 is a flat annular metal spring sheet, and the outer diameter of the spring sheet 34 is equal to the inner diameter of the first groove 9 and the third groove 15, and the inner diameter of the spring sheet 34 is equal to the inner diameter of the cylinder 25. An annular third sealing element 40 is installed in both the first annular groove 12 and the second annular groove 17, which fits against the outer wall of the cylinder 25 to form a sealing surface.

[0036] Specific usage process: During installation, the valve core mechanism 2 is installed in the receiving cavity 8. At this time, the spring 34 is in a state of compression deformation. The spring 34 applies a force to the collar 23, causing the sealing base 21 to move towards the ball core 19, so that the first sealing element 22 is tightly attached to the ball core 19 to form a sealing surface. When the first sealing element 22 abuts against the ball core 19, the sealing base 21 can no longer move towards the ball core 19. Therefore, the force applied by the spring 34 will also drive the collar 23 to move relative to the sealing base 21, so that the second sealing element 24 located between the two arches towards the inner wall of the valve seat 1 under the force of the arc-shaped extrusion surface 30 to form a sealing surface.

[0037] Example 2: like Figure 5 As shown, the difference between this embodiment and Embodiment 1 is only that the spring 34 is a plate-shaped annular shape. The outer ring of the spring 34 facing the bottom surface of the adjacent first groove 9 and third groove 15 has a first annular cut 35, and the inner ring of the spring 34 facing the collar 23 has a second annular cut 36. The depth of the first annular cut 35 is half the thickness of the spring 34, and the angle of the first annular cut 35 is equal to the inclination angle of the bottom surface of the first groove 9 and third groove 15. The depth of the second annular cut 36 is also half the thickness of the spring 34, and the angle of the second annular cut 36 is equal to the inclination angle of the collar 23 facing away from the mounting base 26.

[0038] Example 3: like Figure 6As shown, the difference between this embodiment and Embodiment 1 is only that the spring 34 is a plate-shaped annular shape. The outer ring of the spring 34 facing the bottom surface of the adjacent first groove 9 and third groove 15 has a first annular protrusion 37 formed therein, and the inner ring of the spring 34 facing the collar 23 has a second annular protrusion 38 formed therein. The first annular protrusion 37, facing the bottom surface of the adjacent first groove 9 or third groove 15, slopes from all sides towards the center and away from the mounting base 26, and the angle of inclination is equal to the angle of inclination of the bottom surface of the first groove 9 and third groove 15. The side of the first annular protrusion 37 near the inner ring of the spring 34 transitions smoothly with the surface of the spring 34 through an arc surface. The transition arc surface between the first annular protrusion 37 and the surface of the spring 34 includes an outer convex section adjacent to the first annular protrusion 37 and an inner concave section formed on the spring 34, wherein the inner concave section extends from the side of the outer ring of the spring 34 near the first annular protrusion 37 to the side near the inner ring of the spring 34. From a cross-sectional perspective, the radius of curvature of the convex section is greater than the difference between the inner and outer radii of the spring 34, while the radius of curvature of the concave section is greater than the outer diameter of the spring 34. The location with the greatest concave depth in the concave section is the middle of the spring 34. The second annular protrusion 38, facing the collar 23, slopes from all sides towards the center and away from the mounting base 26, and the angle of inclination is equal to the angle of inclination of the collar 23 facing away from the mounting base 26. The side of the second annular protrusion 38 near the inner ring of the spring 34 transitions smoothly with the surface of the spring 34 through an arc surface. The radius of curvature of the transition arc surface of the second annular protrusion 38 is greater than the difference between the inner and outer radii of the spring 34, and the second annular protrusion 38 does not form a concave section on the surface of the spring 34.

[0039] During installation, as the spring 34 deforms under stress, the central part of the spring 34, corresponding to the position with the greatest depth of the concave section, undergoes the greatest deformation, while the deformation decreases as it approaches the sides of the concave section. After deformation, the spring 34 transitions to a state where its transition arc surface abuts against the bottom surface of the collar 23, the first groove 9, or the third groove 15, applying force to the collar 23. This process continues until, during use, the inclined surfaces of the first annular protrusion 37 and the second annular protrusion 38 abut against the bottom surface of the collar 23, the first groove 9, or the third groove 15.

[0040] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A cryogenic ball valve, comprising a valve seat (1), a valve core mechanism (2) located within the valve seat (1), and a valve stem (3) connected to the valve core mechanism (2); characterized in that, The valve seat (1) includes a receiving cavity (8), a first groove (9) and a third groove (15) connected to the receiving cavity (8). The bottom surfaces of the first groove (9) and the third groove (15) are conical surfaces that are inclined from the periphery to the center and away from the receiving cavity (8), with an inclination angle of 10-30 degrees. The valve core mechanism (2) includes a ball core (19) located in the receiving cavity (8), and two sets of sealing components (20) located in the first groove (9) and the third groove (15) that cooperate with and seal the ball core (19). The sealing components (20) include a sealing base (21), a first sealing element (22) installed on the side of the sealing base (21) facing the ball core (19), a collar (23) sleeved on the outside of the sealing base (21), and a second sealing element (24) located between the sealing base (21) and the collar (23). The collar (23) is inclined from all sides towards the center and away from the receiving cavity (8) on the side facing the bottom surface of the adjacent first groove (9) or third groove (15), and the inclination angle is the same as the bottom surface of the adjacent first groove (9) and third groove (15). Plate-shaped annular springs (34) are provided between the bottom surface of the first groove (9) and the collar (23) and between the bottom surface of the third groove (15) and the collar (23).

2. The cryogenic ball valve according to claim 1, characterized in that, The bottom surface inclination angle of the first groove (9) and the third groove (15) is 15 degrees.

3. The cryogenic ball valve according to claim 1, characterized in that, The sealing base (21) includes a cylindrical body (25) and a mounting seat (26) formed on the end of the cylindrical body (25) facing the ball core (19). The mounting seat (26) has an arc-shaped guide surface (27) formed on the side facing the ball core (19). The arc-shaped guide surface (27) is inclined from the periphery to the center and away from the ball core (19). The arc-shaped guide surface (27) has an annular mounting groove (28) around the cylindrical body (25). The first sealing element (22) is embedded in the mounting groove (28).

4. The cryogenic ball valve according to claim 3, characterized in that, The first seal (22) is annular, and the side of the first seal (22) facing the ball core (19) is formed with an arc-shaped contact surface (29) that fits with the surface of the ball core (19).

5. The cryogenic ball valve according to claim 3 or 4, characterized in that, The mounting base (26) has an arc-shaped extrusion surface (30) formed on the side facing away from the ball core (19), an annular extension surface (31) located at the end of the arc-shaped extrusion surface (30) near the cylinder (25) and parallel to the surface of the cylinder (25), and a transition surface (32) located at the end of the annular extension surface (31) away from the arc-shaped extrusion surface (30) and perpendicular to the surface of the cylinder (25). The inner wall of the collar (23) fits against the outer wall of the cylinder (25). The side of the collar (23) facing the mounting base (26) has an annular clearance groove (33) formed. The width of the clearance groove (33) is equal to the width of the transition surface (32). When the collar (23) abuts against the second seal (24), there is a gap between the bottom surface of the clearance groove (33) and the transition surface (32).

6. The cryogenic ball valve according to claim 5, characterized in that, The second seal (24) is annular and located between the mounting base (26) and the collar (23). The inner wall of the second seal (24) is in contact with the annular extension surface (31), and the outer wall of the second seal (24) is in contact with the inner wall of the valve seat (1). The other two sides of the second seal (24) are in contact with the arc-shaped extrusion surface (30) and the end face of the collar (23), respectively.

7. The cryogenic ball valve according to claim 3, characterized in that, The outer diameter of the spring (34) is equal to the inner diameter of the first groove (9) and the third groove (15), and the inner diameter of the spring (34) is equal to the inner diameter of the cylinder (25).

8. The cryogenic ball valve according to claim 1, characterized in that, The valve seat (1) is provided with a left flow channel (11) and a right flow channel (39). The bottom surface of the first groove is formed with a second groove (10) with a diameter smaller than that of the first groove (9). The bottom surface of the second groove (10) is connected to the left flow channel (11), and the diameter of the second groove (10) is larger than that of the left flow channel (11). Two first annular grooves (12) are formed on the inner wall of the second groove (10). The bottom surface of the third groove (15) is formed with a fourth groove (16) with a diameter smaller than that of the third groove (15). The bottom surface of the fourth groove (16) is connected to the right flow channel (39), and the diameter of the fourth groove (16) is larger than that of the right flow channel (39). Two second annular grooves (17) are formed on the inner wall of the fourth groove (16). Annular third seals (40) are installed in both the first annular groove (12) and the second annular groove (17).

9. The cryogenic ball valve according to claim 1, characterized in that, The valve seat (1) includes a left valve body (4), a right valve cover (5) and a stuffing box (6) installed above the left valve body (4). A first sealing ring (7) is provided between the left valve body (4) and the stuffing box (6) to form a sealing surface by compression. A sealing groove (13) is formed on the side of the left valve body (4) facing the right valve cover (5). A second sealing ring (14) is embedded in the sealing groove (13). A sealing protrusion (18) corresponding to the sealing groove (13) is formed on the side of the right valve cover (5) facing the left valve body (4).

10. The cryogenic ball valve according to claim 1, characterized in that, The spring (34) is a plate-shaped ring. The outer ring of the spring (34) facing the bottom surface of the adjacent first groove (9) and third groove (15) has a first annular cut (35). The inner ring of the spring (34) facing the collar (23) has a second annular cut (36). The depth of the first annular cut (35) is half the thickness of the spring (34). The angle of the first annular cut (35) is equal to the inclination angle of the bottom surface of the first groove (9) and third groove (15). The depth of the second annular cut (36) is half the thickness of the spring (34). The angle of the second annular cut (36) is equal to the inclination angle of the collar (23) facing away from the mounting base (26).

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