A multi-elastic seal compensation high-pressure ultra-low temperature ball valve

Abstract

A high-pressure, ultra-low-temperature ball valve with multiple elastic seals and compensation aims to address the issues of seal failure caused by valve shrinkage deformation under the dual effects of ultra-low temperatures and high pressures, as well as insufficient valve seat elastic compensation capacity. The hollow ball design significantly reduces the uneven shrinkage deformation of the ball under the dual effects of ultra-low temperatures and high pressures, improving sealing performance. This also addresses the issue of valve stem leakage under the dual effects of ultra-low temperatures and high pressures, thereby improving the reliability of the high-pressure, ultra-low-temperature ball valve. The valve body cavity houses a hollow ball, flanked by a dual-piston, multi-elastic seal compensation structure with four-fold elastic compensation. A valve cover is positioned above the valve body. The two are bolted together and equipped with a valve body seal compensation disc spring. End seals are located on the contact surfaces. The valve stem extends through a through hole in the valve cover. Its lower end is flexibly connected to the hollow ball structure. Bearings are located at the upper and lower axes of the hollow ball structure to reduce valve operating torque. The valve stem is also equipped with a multiple packing seal structure to ensure a reliable seal around the packing.

Description

Technical Field

[0001] The invention belongs to the technical field of valves, and in particular relates to a multi-elastic seal compensation high-pressure ultra-low temperature ball valve structure. Background Art

[0002] Ultra-cryogenic ball valves account for over 60% of liquid hydrogen receiving station systems. Low-pressure liquid hydrogen ball valves in liquid hydrogen receiving station unloading systems will result in excessively long unloading times and significantly reduced unloading efficiency. High-pressure liquid hydrogen unloading will become inevitable, and sealing issues at high pressure and ultra-low temperatures are currently a technical bottleneck for cryogenic ball valves.

[0003] Existing cryogenic ball valves typically utilize a soft seal seat and a solid ball structure. Under the combined effects of ultra-low temperatures and high pressures, the valve shrinks unevenly, and insufficient seat compensation can easily lead to seal failure and subsequent leakage, seriously impacting the safe and reliable operation of the system. Furthermore, existing cryogenic valve packings typically utilize rectangular or V-shaped packings, commonly found in room-temperature packings. However, these packings struggle to maintain reliable sealing under the cyclical loads of temperature and pressure under liquid hydrogen high-pressure and ultra-low temperature conditions. Unreliable packing structures can lead to media leakage, impacting system stability and posing safety risks and economic losses. Summary of the Invention

[0004] The first purpose of the present invention is to provide a multi-elastic sealing compensation structure to solve the problem of sealing failure caused by valve shrinkage deformation under the dual effects of ultra-low temperature and high pressure and the problem of insufficient elastic compensation capacity of the valve seat.

[0005] The second purpose of the present invention is to provide a hollow ball structure for a high-pressure ultra-low temperature ball valve. The hollow ball design greatly reduces the unevenness of the cold shrinkage deformation of the ball under the dual effects of ultra-low temperature and high pressure, thereby improving the sealing performance.

[0006] The third object of the present invention is to provide a packing multiple sealing structure to solve the problem of valve stem leakage under the dual effects of ultra-low temperature and high pressure, and to improve the reliability of the high-pressure and ultra-low temperature ball valve.

[0007] The present invention is a multi-elastic seal compensation high-pressure ultra-low temperature ball valve, comprising a valve body 1, a valve cover 2, a hollow ball 3, a multi-elastic seal compensation structure 4, an end face sealing ring 5, a valve body seal compensation disc spring 6, a valve stem 7, and a packing multiple sealing structure 8. The valve body 1 is a top-mounted valve body, and the lower end of the valve cover 2 is connected to the upper end of the valve body 1 by bolts; the multi-elastic seal compensation structures 4 are respectively installed on both sides of the inside of the valve body 1, and the hollow ball 3 is between the left and right multi-elastic seal compensation structures 4. The lower end of the valve stem 7 passes through the valve hole of the valve cover 2 and is connected to the upper part of the hollow ball 3; the packing multiple sealing structure 8 is installed on the upper part of the valve cover and the valve stem 7, and the two are connected by bolts.

[0008] Compared with the existing technology, the present invention has the following advantages: the hollow ball structure effectively reduces the unevenness of structural shrinkage deformation, thereby improving sealing performance; at the same time, the hollow ball structure reduces the ball structure mass, which facilitates the lightweighting of ultra-low temperature and high-pressure ball valves. The elastic seal compensation high-pressure ultra-low temperature ball valve achieves four-fold sealing compensation for valve shrinkage deformation under the dual effects of ultra-low temperature and high pressure, improving the sealing performance of high-pressure ultra-low temperature valves and enhancing the safety and reliability of the valves. The packing multi-seal structure provides a four-fold stem packing seal, reliably solving the problem of leakage at the stem packing of ultra-low temperature valves, improving the stem packing sealing performance and the smoothness of the stem operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the overall structure of the present invention, Figure 2 This is a schematic diagram of a multi-elastic seal compensation structure. Figure 3 This is a half-section diagram of the double elastic groove metal valve seat structure. Figure 4 This is a schematic diagram of the double-piston effect seal control of the multi-elastic seal compensation structure. Figure 5 This is a half-section diagram of the hollow sphere structure. Figure 6 Schematic diagram of the packing multiple sealing structure. The reference numerals and corresponding names are: 1. Valve body, 2. Valve cover, 3. Hollow ball structure, 31. Hollow ball upper shaft, 32. Hollow ball lower shaft, 33. Hollow ball flow channel, 34. Hollow ball spherical surface, 4. Multi-elastic sealing compensation structure, 41. Soft sealing ring, 42. Double elastic groove metal valve seat, 421. Thin edge at the bottom of the valve seat groove, 422. Valve seat elastic groove 1, 423. Valve seat elastic groove 2, 424. Valve seat stepped section 1, 425. Valve seat step 426. Valve seat groove, 43. Valve seat elastic compensation disc spring, 44, bellows seal, 5, end step 2, face seal ring, 6, valve body seal compensation disc spring, 7, valve stem, 8, packing multiple sealing structure, 81, valve stem shaft seal plug, 82, valve stem guide sleeve, 83, combined graphite packing, 84, packing spacer, 85, packing gland, 86, O-ring, 87, packing gland, 88, spring washer, 89, packing compensation disc spring, A1, medium transverse contact area 1, A2: medium transverse contact area 2, A3: medium transverse contact area 3, A4: medium transverse contact area 4. Implementation Method

[0010] like Figure 1As shown, the present invention is a multi-elastic seal compensation high-pressure ultra-low temperature ball valve, including a valve body 1, a valve cover 2, a hollow ball 3, a multi-elastic seal compensation structure 4, an end face sealing ring 5, a valve body seal compensation disc spring 6, a valve stem 7, and a packing multiple sealing structure 8. The valve body 1 is a top-mounted valve body, and the lower end of the valve cover 2 is connected to the upper end of the valve body 1 by bolts; the multi-elastic seal compensation structures 4 are respectively installed on both sides of the inside of the valve body 1, and the hollow ball 3 is between the left and right multi-elastic seal compensation structures 4. The lower end of the valve stem 7 passes through the valve hole of the valve cover 2 and is connected to the upper part of the hollow ball 3; the packing multiple sealing structure 8 is installed on the upper part of the valve cover and the valve stem 7, and the two are connected by bolts.

[0011] like Figure 1 、 Figure 2 、 Figure 3 As shown, the elastic sealing compensation structure 4 includes a soft sealing ring 41, a double elastic groove metal valve seat 42, a valve seat elastic compensation disc spring 43 and a bellows seal 44; the soft sealing ring 41 is installed in the groove at the front end of the double elastic groove metal valve seat 42, and the soft sealing ring 41 is fixed by the thin edge 421 at the bottom of the groove, and the soft sealing ring provides sealing compensation during the first low-temperature shrinkage; the front end of the double elastic groove metal valve seat 42 is an elastic groove structure, including a valve seat elastic groove 1 422 and a valve seat elastic groove 2 423, and the valve seat elastic groove provides sealing compensation during the second and third low-temperature shrinkage; the rear end of the double elastic groove metal valve seat 42 is a stepped structure, including a valve seat stepped section 1 424 and a valve seat stepped section 2 425; the valve seat elastic compensation disc spring 43 is arranged on the valve seat stepped section 2 425, and the outer diameter end of the valve seat elastic compensation disc spring 43 is aligned with the valve seat elastic groove 2 423 is in line contact, and the inner diameter end of the valve seat elastic compensation disc spring 43 is in line contact with the valve body 1. The valve seat elastic compensation disc spring provides the fourth level of sealing compensation during low-temperature shrinkage; one end of the bellows seal 44 is fixedly connected to the double elastic groove metal valve seat 42, and the other end of the bellows seal 44 abuts against the valve body 1 to achieve reliable sealing.

[0012] like Figure 1 、 Figure 4 As shown, the elastic sealing compensation structure 4 satisfies A1<A2, A3<A4, and has a double-piston sealing effect.

[0013] like Figure 2 、 Figure 5 As shown, the wall thickness of the hollow ball 3 is uniform; the upper shaft 31 and the lower shaft 32 of the hollow ball are provided with bearings; the spherical surface 34 of the hollow ball and the soft sealing ring 41 are surface contact sealed.

[0014] like Figure 1 As shown, a valve body sealing compensation disc spring 6 is provided at the connection between the valve body 1 and the valve cover 2, and an end face sealing ring 5 is provided at the connection between the lower end of the valve cover and the valve body.

[0015] like Figure 6 As shown, the packing multiple sealing structure 8 includes a valve stem shaft seal plug 81, a valve stem guide sleeve 82, a combined graphite packing 83, a packing spacer 84, a packing gland 85, an O-ring 86, a packing gland 87, a spring washer 88, and a packing compensation disc spring 89.

[0016] The following examples further illustrate the technical content of the present invention. Figures 1 to 6 As shown, the multi-elastic seal compensation high-pressure ultra-low temperature ball valve provided by an embodiment of the present invention includes a valve body 1, a valve cover 2, a hollow ball structure 3, a multi-elastic seal compensation structure 4, an end face sealing ring 5, a valve body seal compensation disc spring 6, a valve stem 7, and a packing multiple sealing structure 8.

[0017] In this embodiment of the present invention, the multi-elastic seal compensation structure 4 comprises a soft seal ring 41, a metal valve seat with two elastic grooves 42, a valve seat elastic compensation disc spring 43, and a bellows seal 44. The valve seat elastic compensation disc spring 43 generates the first level of elasticity, the second and third levels of elasticity are generated by the elastic groove structures 422 and 423 in the metal valve seat with two elastic grooves, and the fourth level of elasticity is generated by the soft seal ring 41.

[0018] It should be noted that the initial preload force generated by the valve seat elastic compensation disc spring 43 is ultimately loaded onto the sealing surface, generating sufficient initial preload sealing pressure ratio. When the low-temperature medium flows into the valve, the valve shrinks to a large extent due to temperature changes. The multi-elastic sealing compensation structure 4 provides the valve with multiple protections for deformation compensation, ensuring the sealing reliability of the ball valve under liquid hydrogen high-pressure and ultra-low temperature conditions.

[0019] It should be noted that the soft sealing ring 41 in the high-pressure ultra-low temperature ball valve can be made of PCTFE or a material with better performance at low temperatures.

[0020] like Figure 3 、 Figure 4 As shown, A1 represents the lateral contact area between the valve cavity medium and the upper portion of the valve seat groove 426; A2 represents the lateral contact area between the valve cavity medium and the upper portion of the valve seat stepped section 2 425; A3 represents the lateral contact area between the valve body flow path medium and the lower portion of the valve seat groove 426; and A4 represents the lateral contact area between the valve body flow path medium and the lower portion of the valve seat stepped section 1 424. The multi-elastic seal compensation structure 4 exhibits a dual-piston effect. By controlling the size relationship between the contact surfaces of the dual-elastic groove metal valve seat 42 and the medium, ensuring that A1 < A2 and A3 < A4, the dual-elastic groove metal valve seat 42 can securely hold the hollow ball structure 3, regardless of the pressure differential across the valve, ensuring a complete seal between the soft seal ring 41 and the hollow ball structure 3.

[0021] The multi-elastic sealing compensation structure 4 is provided with a bellows seal 44 between the valve body 1 and the double elastic groove metal valve seat 42. When the pressure of the liquid hydrogen medium enters the inner layer or outer layer of the bellows, the pressure pushes it to stretch and then pushes the double elastic groove metal valve seat 42 to press the hollow ball structure 3, which is conducive to reliable sealing between the soft sealing ring 41 and the hollow ball structure 3.

[0022] It should be noted that one end of the bellows seal 44 is fixedly connected to the double elastic groove metal valve seat 42 , and the other end of the bellows seal 44 abuts against the valve body 1 , thereby achieving sealing between the valve body 1 and the multi-elastic sealing compensation structure 4 .

[0023] The hollow ball 3 has a uniform wall thickness, a more reasonable structure, and a higher strength. The unevenness of the structural cold shrinkage deformation under the dual effects of ultra-low temperature and high pressure is greatly reduced. In addition, the hollow ball 3 is light in weight, consumes less materials, and reduces costs.

[0024] It should be noted that the diameter of the hollow ball flow channel 33 is equal to the diameter of the inlet and outlet ports of the valve body 1, ensuring that the ball valve has good flow capacity and pigging maintenance performance.

[0025] It should be noted that the hollow ball upper shaft 31 and the hollow ball lower shaft 32 can be provided with bearings with a small friction coefficient, which greatly reduces the operating torque of the valve.

[0026] The valve body 1 is a top-mounted valve body, which is convenient for maintenance and reduces the influence of pipeline load under temperature and pressure alternating load, and the sealing performance is more reliable; the valve body 1 and the valve cover 2 are connected by bolts and a valve body sealing compensation disc spring 6 is provided, and an end face sealing ring 5 is provided at the connection between the lower end of the valve cover 2 and the valve body 1 to ensure reliable sealing of the valve body.

[0027] It should be noted that the end face sealing ring 5 is PTFE+Inconel or a PTFE seal having better performance under high pressure and ultra-low temperature.

[0028] The multi-elastic sealing compensation structures 4 are respectively installed on both sides of the valve body 1, and the hollow ball structure 3 is between the left and right multi-elastic sealing compensation structures 4. The hollow ball surface 34 and the soft sealing ring 41 are in surface contact sealing, and the valve seat seal is reliable.

[0029] The packing multiple sealing structure 8 is installed on the upper part of the valve cover 2 and the valve stem 7, and the two are connected by bolts. The packing compensation disc spring 89 provides packing load compensation.

[0030] The packing multiple sealing structure 8 has a stem shaft seal with a flood plug 81 to create the first packing seal, two sets of combined graphite packing 83 to create the second and third seals, and an O-ring 86 to create the fourth seal. The stem guide sleeve 82 is used to position the stem to prevent the stem from deflecting and affecting the seal.

Claims

1. A multi-elastic seal compensation high-pressure ultra-low temperature ball valve, comprising a valve body (1), a valve cover (2), a hollow ball (3), a multi-elastic seal compensation structure (4), an end face sealing ring (5), a valve body seal compensation disc spring (6), a valve stem (7), and a packing multi-seal structure (8), characterized in that: The valve body (1) is a top-mounted valve body, and the lower end of the valve cover (2) is connected to the upper end of the valve body (1) by bolts; the multi-elastic sealing compensation structure (4) is respectively installed on both sides of the interior of the valve body (1), and the hollow ball (3) is between the left and right multi-elastic sealing compensation structures (4); the lower end of the valve stem (7) passes through the valve hole of the valve cover (2) and is connected to the upper part of the hollow ball (3); The packing multiple sealing structure (8) is installed on the valve cover and the upper part of the valve stem (7), and the two are connected by bolts; The multi-elastic sealing compensation structure (4) includes a soft sealing ring (41), a double elastic groove metal valve seat (42), a valve seat elastic compensation disc spring (43) and a bellows seal (44); the soft sealing ring (41) is installed in the valve seat groove (426) at the front end of the double elastic groove metal valve seat (42), and the soft sealing ring (41) is fixed by buckling the thin edge (421) at the lower part of the valve seat groove, and the soft sealing ring provides the first level of sealing compensation during low temperature shrinkage; the front end of the double elastic groove metal valve seat (42) is an elastic groove structure, including a valve seat elastic groove 1 (422) and a valve seat elastic groove 2 (423), and the valve seat elastic groove 1 (422) and the valve seat elastic groove 2 (423) provide the second and third levels of low temperature respectively. Sealing compensation during temperature shrinkage; the rear end of the double elastic groove metal valve seat (42) is a stepped structure, including a valve seat stepped section 1 (424) and a valve seat stepped section 2 (425); the valve seat elastic compensation disc spring (43) is arranged on the valve seat stepped section 1 (424), the outer diameter end of the valve seat elastic compensation disc spring (43) is in line contact with the valve seat elastic groove 2 (423), and the inner diameter end of the valve seat elastic compensation disc spring (43) is in line contact with the valve body (1), and the valve seat elastic compensation disc spring provides the fourth level of sealing compensation during low temperature shrinkage; one end of the bellows seal (44) is fixedly connected to the double elastic groove metal valve seat (42), and the other end of the bellows seal (44) is in contact with the valve body (1) to achieve reliable sealing; The multi-elastic sealing compensation structure (4) satisfies A1<A2, A3<A4, and has a double piston sealing effect, A1 is the lateral contact area between the valve cavity medium and the upper part of the valve seat groove (426), A2 is the lateral contact area between the valve cavity medium and the upper part of the valve seat step section 2 (425), A3 is the lateral contact area between the valve body flow channel medium and the lower part of the valve seat groove (426), and A4 is the lateral contact area between the valve body flow channel medium and the lower part of the valve seat step section 1 (424).

2. The multi-elastic seal compensation high-pressure cryogenic ball valve according to claim 1, characterized in that: The hollow ball (3) has a uniform wall thickness; the upper shaft (31) and the lower shaft (32) of the hollow ball are provided with bearings; and a surface contact seal is formed between the spherical surface (34) of the hollow ball and the soft sealing ring (41).

3. The multi-elastic seal compensation high-pressure cryogenic ball valve according to claim 1, characterized in that: A valve body sealing compensation disc spring (6) is provided at the connection between the valve body (1) and the valve cover (2), and an end face sealing ring (5) is provided at the connection between the lower end of the valve cover and the valve body.

4. The multi-elastic seal compensation high-pressure cryogenic ball valve according to claim 1, characterized in that: The packing multiple sealing structure (8) includes a valve stem shaft seal plug (81), a valve stem guide sleeve (82), a combined graphite packing (83), a packing spacer (84), a packing gland (85), an O-ring (86), a packing gland (87), a spring washer (88), and a packing compensation disc spring (89).

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