Low temperature seal compensated ball valve

Abstract

The application discloses a low-temperature sealing compensation type ball valve and relates to the technical field of low-temperature ball valves, so that an operator can rotate a hand wheel of an executing mechanism, thereby rotating a valve core, and switching the ball valve, the valve core is sealed by multiple sealing mechanisms, leakage caused by sealing failure is avoided, when the temperature drops to low temperature, a compensation block of the multiple sealing mechanisms pushes the valve seat to move towards the valve core, thereby compensating for insufficient sealing force caused by low-temperature cold contraction deformation of the valve core and the valve seat, and the balance block of the multiple sealing mechanisms adjusts the sealing force on the upper and lower sides of the valve seat, thereby avoiding the wear of the lower sealing element being greater than that of the upper sealing element, avoiding adhesion failure caused by wear deformation, and further ensuring the effective sealing performance of the sealing ring on the valve core during long-term use.

Description

Technical Field

[0001] This invention relates to the field of cryogenic ball valve technology, specifically a cryogenic sealing compensation ball valve. Background Technology

[0002] Cryogenic ball valves are a type of valve specifically designed for low-temperature operating conditions. Their operating temperature range is generally from -40℃ to -196℃. Due to the low operating temperature of cryogenic ball valves, components inside the ball valve, such as the valve seat, valve core, and compensating spring, will undergo uneven shrinkage and deformation due to cold. This leads to an increase in the gap between the valve seat and the valve core, a decrease in the elasticity of the compensating spring, and a reduction in the sealing force of the valve seat on the valve core. Consequently, the valve cannot effectively seal the valve core, resulting in leakage at low temperatures.

[0003] Furthermore, cryogenic ball valves are typically used for liquid media. When the media flows inside the valve cavity, it is subject to gravity, causing the media to naturally accumulate downwards. This results in the impact force of the media on the lower side of the ball valve being much greater than that on the upper side. Consequently, during long-term use, the lower side of the sealing ring wears much more than the upper side, causing the sealing ring to fail to fit the valve core properly and thus failing to effectively seal the valve core. This can easily lead to leakage during valve operation. Summary of the Invention

[0004] The purpose of this invention is to solve the problem in the prior art that the sealing force of the sealing ring is insufficient or the fit fails due to uneven wear caused by low temperature deformation and long-term use, thus failing to form an effective seal for the valve core. Therefore, a low temperature sealing compensation ball valve is proposed.

[0005] To address the above problems, the present invention provides the following technical solution:

[0006] A cryogenic sealing compensation ball valve includes an actuator, a valve body, a valve core inside the valve body, a multi-seal mechanism between the valve body and the valve core, a rotating mechanism on the valve core, a packing seal mechanism between the valve body and the rotating mechanism, and the rotating mechanism is connected to the actuator.

[0007] The multi-seal mechanism includes a valve seat, a compensation block, two balance blocks, and a sealing ring. The valve seat provides sealing force to the sealing ring, the compensation block is used to compensate for the sealing force of the valve seat, and the compensation block balances the sealing force on the upper and lower sides of the valve seat through the two balance blocks.

[0008] The valve seat axis is parallel to the direction of medium flow, the sealing ring seals the valve core, and the side of the valve seat closest to the rotating mechanism is the upper side.

[0009] The ball valve is opened and closed by rotating the valve core and the actuator at both ends of the rotating mechanism. The valve core is rotated by the operator's handwheel, which in turn rotates the actuator. The valve core is sealed by a sealing ring and a multi-seal mechanism to prevent leakage due to seal failure. A compensation block pushes the valve seat towards the valve core when the temperature drops to a low level, compensating for insufficient sealing force caused by low-temperature contraction and deformation of the valve core and seat. Two balance blocks adjust the sealing force on the upper and lower sides of the valve seat according to the impact force of the medium on the valve seat. The valve seat axis is parallel to the medium flow direction, with the side of the valve seat closer to the rotating mechanism being the upper side. This prevents the lower seal from wearing more material than the upper seal, thus avoiding sealing failure due to wear and deformation, and ensuring the valve core's sealing performance.

[0010] Furthermore, the multi-sealing mechanism also includes an adjusting plate, with two connecting rods on one side of the adjusting plate;

[0011] The balance weight has an arc-shaped groove;

[0012] The valve body is provided with two sliding grooves, which are connected to each other;

[0013] One end of the connecting rod has a protrusion, which is hemispherical;

[0014] The two balance blocks are slidably connected to the two sliding grooves respectively, and the protrusion is slidably connected to the arc-shaped groove.

[0015] An adjusting plate is installed at the bent end of the compensation block, allowing the compensation block and the adjusting plate to abut against each other. Connecting rods are installed on the upper and lower sides of the adjusting plate, with one end fixed to the adjusting plate and the other end having a hemispherical protrusion that abuts against the arc-shaped groove of the balance block. This allows one end of the connecting rod to slide on the arc-shaped groove. The valve body has two connected sliding grooves at the upper and lower ends of the flow channel. The two balance blocks and the two sliding grooves are slidably connected. When the medium causes a greater impact on the lower side of the valve seat than on the upper side, or when the sealing force is unevenly distributed due to cold contraction and deformation on the upper and lower sides, one balance block slides into the sliding groove, thereby pushing the hydraulic medium in the sliding groove and causing the other balance block to slide out of the sliding groove. This balances the pressure of the two balance blocks and causes the adjusting plate to tilt slightly, thereby balancing the sealing force on the upper and lower sides of the valve seat. This prevents the lower seal from wearing much more than the upper seal, which could lead to sealing failure due to poor fit.

[0016] Furthermore, the multi-sealing mechanism also includes a compensating spring, with an annular plate on one side of the compensating block and the compensating spring located between the annular plate and the valve seat;

[0017] The valve seat has a groove;

[0018] The compensation block has an outer layer and an inner layer, and the coefficient of thermal expansion of the outer layer material is smaller than that of the inner layer material.

[0019] The end of the compensation block away from the valve core is curved, the sealing ring is located in the groove, and the adjusting plate and the compensation block abut against each other.

[0020] By setting a compensating spring between the annular plate and the valve seat, the compensating spring is initially in a compressed state. The elastic force released by the compensating spring ensures that the sealing ring in the valve seat groove is always tightly attached to the valve core. By setting the sealing ring to an elastic material, the sealing gap is automatically compensated, thus forming the first and second layers of seal. A compensating block is fixed on the other side of the annular plate. The compensating block has an annular structure and is divided into an outer layer and an inner layer. The coefficient of thermal expansion of the outer layer material is less than that of the inner layer material. When the valve is closed, both the outer and inner layers bend outward in the initial state. When the valve is opened, the low-temperature medium flows through, and the temperature drops. As the temperature drops, the bending of the compensating block decreases, causing the outer and inner layers to gradually straighten. This causes the compensating block to push the valve seat towards the valve core, increasing the sealing force of the valve seat and forming the third layer of seal, thus forming a multi-layer seal.

[0021] Furthermore, the compensation block has several slots and an arc-shaped surface;

[0022] The curved surface and the adjusting plate abut against each other.

[0023] By setting several slots at the free end of the compensation block, cracking caused by stress concentration when the compensation block deforms due to temperature drop is avoided. By setting an arc-shaped surface at the end where the compensation block and the adjusting plate abut, the compensation block can slide smoothly when it deforms, thereby pushing the annular plate and avoiding jamming.

[0024] Furthermore, the valve core has a hollow groove inside and a flow channel on the valve core;

[0025] The upper cross-section of the flow channel is circular, and the lower cross-section of the flow channel is elliptical.

[0026] By setting a hollow groove inside the valve core, the valve core is formed into a hollow ball structure, which reduces the impact of low temperature deformation on the valve core. By setting a flow channel, the medium flows through the flow channel when the valve is working. By setting the flow channel to have a circular arc shape on the upper side and an elliptical arc shape on the lower side of the cross-section, the distribution of the medium when the medium flows through the valve core is adjusted, reducing the impact force of the medium on the lower side of the valve core.

[0027] Furthermore, the valve body is provided with several guide grooves, which are distributed in a ring and have inclined surfaces.

[0028] The angle of several inclined planes gradually decreases as they approach the rotating mechanism.

[0029] By setting an annular ring on the side of the valve body near the medium inlet, and setting several guide grooves along the flow channel on the annular ring, and setting inclined surfaces in the guide grooves towards the valve core, the angle of the inclined surfaces gradually increases from top to bottom, so that the medium near the inner wall of the flow channel generates a force that flows towards the middle. By gradually increasing the angle of several inclined surfaces from top to bottom, the medium on the lower side is subjected to a greater force, thereby reducing the impact force on the inner wall of the valve body when the medium flows through, and thus reducing the impact force on the valve seat, and reducing the uneven wear of the lower and upper sealing rings.

[0030] Furthermore, the rotating mechanism includes a lower valve stem, an upper valve stem is provided above the lower valve stem, and a preload spring is provided between the lower valve stem and the upper valve stem.

[0031] The valve stem is divided into a lower valve stem and an upper valve stem, which can slide vertically between the upper and lower valve stems. A preload spring is installed between them. The preload spring is initially in a compressed state, so that the lower valve stem is always in contact with the valve core.

[0032] Furthermore, a conical block is provided below the lower valve stem;

[0033] The valve core is provided with a tapered groove;

[0034] The conical block and the conical groove fit together.

[0035] By setting a conical block at the bottom of the lower valve stem and a corresponding conical groove on the valve core, when the valve core undergoes cold shrinkage deformation, the preload spring can press the conical block into the conical groove, ensuring that there is no loosening between the lower valve stem and the valve core, thereby ensuring the control accuracy of the valve stem over the valve core.

[0036] Furthermore, the packing sealing mechanism includes a packing gland, a packing assembly below the packing gland, and a sealing ring below the packing assembly.

[0037] The valve stem is sealed by installing a packing gland between the valve stem and the valve body, and then installing a packing assembly and a sealing ring below the packing gland.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] 1. By setting a double-layered compensation block, it deforms in a specific direction when the temperature drops, thereby pushing the valve seat to move and enhancing the sealing force. Combined with the compensation spring and elastic sealing ring, a multi-layer sealing structure is formed to avoid sealing failure caused by low-temperature deformation.

[0040] 2. By setting a balance block, the pressure on the upper and lower sealing rings is balanced. In conjunction with the guide groove, the impact force on the valve seat when the medium flows through is reduced, thereby reducing uneven wear that could cause the sealing ring to fail to fit the valve core and resulting in sealing failure, thus improving the service life of the ball valve. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0042] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0043] Figure 3 yes Figure 2 A magnified view of part A;

[0044] Figure 4 This is a schematic diagram of the structure of the multiple sealing mechanism of the present invention;

[0045] Figure 5 This is a schematic diagram of the structure of the compensation block of the present invention;

[0046] Figure 6 yes Figure 2 A magnified view of part B;

[0047] Figure 7 yes Figure 2 A magnified view of a portion of C;

[0048] Figure 8 yes Figure 2 A magnified view of a portion of the image.

[0049] In the diagram: 1. Actuator; 2. Valve body; 21. Sliding groove; 22. Guide groove; 23. Inclined surface; 3. Valve core; 31. Empty groove; 32. Flow channel; 33. Conical groove; 4. Multiple sealing mechanism; 41. Valve seat; 411. Groove; 42. Compensating block; 421. Outer layer; 422. Inner layer; 423. Slot; 424. Arc surface; 43. Balance block; 431. Arc groove; 44. Compensating spring; 45. Annular plate; 46. Adjusting plate; 47. Connecting rod; 471. Protrusion; 48. Sealing ring; 5. Rotating mechanism; 51. Lower valve stem; 52. Upper valve stem; 53. Preload spring; 54. Conical block; 6. Packing sealing mechanism; 61. Packing gland; 62. Packing assembly; 63. Sealing ring. Detailed Implementation

[0050] The embodiments of the present invention will now be further described in conjunction with the accompanying drawings and examples.

[0051] Example: Figures 1-3 As shown, the present invention provides a technical solution: a low-temperature sealing compensation ball valve. The ball valve includes an actuator 1, a valve body 2, a valve core 3 inside the valve body 2, a multi-seal mechanism 4 between the valve body 2 and the valve core 3, a rotating mechanism 5 on the valve core 3, a packing seal mechanism 6 between the valve body 2 and the rotating mechanism 5, and the rotating mechanism 5 is connected to the actuator 1.

[0052] The multi-sealing mechanism 4 includes a valve seat 41, a compensation block 42, two balance blocks 43 and a sealing ring 48. The valve seat 41 provides sealing force to the sealing ring 48. The compensation block 42 is used to compensate for the sealing force of the valve seat 41. The compensation block 42 balances the sealing force on the upper and lower sides of the valve seat 41 through the two balance blocks 43.

[0053] The axis of valve seat 41 is parallel to the direction of medium flow, and the sealing ring 48 seals the valve core 3. The side of valve seat 41 closest to the rotating mechanism 5 is the upper side.

[0054] The rotating mechanism 5 is connected to the valve core 3 and the actuator 1 at both ends, allowing the operator to rotate the handwheel of the actuator 1 to rotate the valve core 3, thereby opening and closing the ball valve. The valve core 3 is sealed by the sealing ring 48, and the valve core 3 is sealed multiple times by the multiple sealing mechanism 4 to prevent leakage caused by seal failure. By setting a compensation block 42, when the temperature drops to a low temperature, the compensation block 42 pushes the valve seat 41 towards the valve core 3, thereby compensating for insufficient sealing force caused by low temperature shrinkage and deformation of the valve core 3 and valve seat 41. By setting two balance blocks 43, the sealing force on the upper and lower sides of the valve seat 41 is adjusted according to the impact force of the medium on the valve seat 41. The axis of the valve seat 41 is parallel to the direction of medium flow, and the side of the valve seat 41 closer to the rotating mechanism 5 is the upper side, thereby avoiding greater wear on the lower sealing element than on the upper sealing element, thus avoiding fit failure caused by wear and deformation, and ensuring the sealing performance of the valve core 3.

[0055] like Figure 4 As shown, the multi-sealing mechanism 4 also includes an adjusting plate 46, and two connecting rods 47 are provided on one side of the adjusting plate 46;

[0056] The balance block 43 is provided with an arc-shaped groove 431;

[0057] The valve body 2 is provided with two sliding grooves 21, and the two sliding grooves 21 are connected.

[0058] One end of the connecting rod 47 is provided with a protrusion 471, which is hemispherical;

[0059] The two balance blocks 43 are slidably connected to the two sliding grooves 21 respectively, and the protrusion 471 is slidably connected to the arc groove 431.

[0060] An adjusting plate 46 is provided at the bent end of the compensation block 42, allowing the compensation block 42 and the adjusting plate 46 to abut against each other. Connecting rods 47 are provided on the upper and lower sides of the adjusting plate 46, with one end of the connecting rod 47 fixed to the adjusting plate 46 and the other end provided with a hemispherical protrusion 471, allowing the protrusion 471 to abut against the arc groove 431 of the balance block 43. This allows one end of the connecting rod 47 to slide on the arc groove 431. Two connected sliding grooves 21 are provided at the upper and lower ends of the flow channel in the valve body 2, and the two balance blocks 43 are slidably connected to the two sliding grooves 21. When the medium causes a greater impact on the lower side of the valve seat 41 than on the upper side of the valve seat 41, or when the sealing force is unevenly distributed due to cold shrinkage deformation on both sides, one balance block 43 slides into the sliding groove 21, thereby pushing the hydraulic medium in the sliding groove 21 and causing the other balance block 43 to slide out of the sliding groove 21, so that the pressure of the two balance blocks 43 is balanced, thereby pushing the adjusting plate 46 to tilt slightly, thereby balancing the sealing force on both sides of the valve seat 41, and avoiding the sealing failure caused by the lower seal being worn much more than the upper seal.

[0061] like Figure 3 and Figure 4 As shown, the multi-sealing mechanism 4 also includes a compensation spring 44. An annular plate 45 is provided on one side of the compensation block 42, and the compensation spring 44 is located between the annular plate 45 and the valve seat 41.

[0062] The valve seat 41 is provided with a groove 411;

[0063] The compensation block 42 is provided with an outer layer 421 and an inner layer 422. The coefficient of thermal expansion of the outer layer 421 is smaller than that of the inner layer 422.

[0064] The end of the compensation block 42 away from the valve core 3 is bent, the sealing ring 48 is located in the groove 411, and the adjusting plate 46 and the compensation block 42 abut against each other.

[0065] A compensating spring 44 is provided between the annular plate 45 and the valve seat 41. The compensating spring 44 is initially in a compressed state. Through the elastic force released by the compensating spring 44, the sealing ring 48 in the groove 411 of the valve seat 41 is always tightly attached to the valve core 3. By making the sealing ring 48 an elastic material, the sealing gap is automatically compensated, thereby forming the first and second layers of sealing. A compensating block 42 is fixedly installed on the other side of the annular plate 45. The compensating block 42 has an annular structure and is divided into an outer layer 421 and an inner layer 422. The coefficient of thermal expansion of the outer layer 421 is less than that of the inner layer 422. When the valve is closed, both the outer layer 421 and the inner layer 422 bend outward in the initial state. When the valve is opened, the low-temperature medium flows through and the temperature drops, which reduces the bending of the compensation block 42 as the temperature drops. This causes the outer layer 421 and the inner layer 422 to gradually straighten, which in turn causes the compensation block 42 to push the valve seat 41 towards the valve core 3, increasing the sealing force of the valve seat 41 and thus forming a third layer of seal, and finally forming a multi-layer seal.

[0066] like Figure 5 As shown, the compensation block 42 has several slots 423 and an arc-shaped surface 424.

[0067] The curved surface 424 and the adjusting plate 46 abut against each other.

[0068] By setting several slots 423 at the free end of the compensation block 42, cracking caused by stress concentration when the compensation block 42 deforms due to temperature drop is avoided. By setting an arc-shaped surface 424 at the end where the compensation block 42 and the adjusting plate 46 abut, the compensation block 42 can slide smoothly when it deforms, thereby pushing the annular plate 45 and avoiding jamming.

[0069] like Figure 2 As shown, the valve core 3 has a hollow groove 31 inside and a flow channel 32 on the valve core 3;

[0070] The upper cross-section of the flow channel 32 is arc-shaped, and the lower cross-section of the flow channel 32 is elliptical.

[0071] By setting a hollow groove 31 inside the valve core 3, the valve core 3 is formed into a hollow ball structure, which reduces the impact of low temperature deformation on the valve core 3. By setting a flow channel 32, the medium flows through the flow channel 32 when the valve is working. By setting the flow channel 32 to have a circular arc on the upper side and an elliptical arc on the lower side of the cross section, the distribution of the medium when the medium flows through the valve core 3 is adjusted, reducing the impact force of the medium on the lower side of the valve core 3.

[0072] like Figure 6 As shown, the valve body 2 is provided with a number of guide grooves 22, which are distributed in a ring, and the guide grooves 22 are provided with inclined surfaces 23.

[0073] Several inclined planes 23 approach the rotating mechanism 5 at angles that gradually decrease.

[0074] By setting an annular ring on the side of the valve body 2 near the medium inlet, and setting several guide grooves 22 along the flow channel on the annular ring, and setting inclined surfaces 23 inclined towards the valve core 3 in the guide grooves 22, the angle of the inclined surfaces 23 gradually increases from top to bottom, so that the medium near the inner wall of the flow channel generates a force to flow towards the middle. By gradually increasing the angle of the several inclined surfaces 23 from top to bottom, the medium on the lower side is subjected to a greater force, thereby reducing the impact force on the inner wall of the valve body 2 when the medium flows through, and thus reducing the impact force on the valve seat 41, and reducing the uneven wear of the lower sealing ring 48 and the upper sealing ring 48.

[0075] like Figure 2 As shown, the rotating mechanism 5 includes a lower valve rod 51, an upper valve rod 52 is provided above the lower valve rod 51, and a preload spring 53 is provided between the lower valve rod 51 and the upper valve rod 52.

[0076] The valve stem is divided into a lower valve stem 51 and an upper valve stem 52. The upper valve stem 52 and the lower valve stem 51 can slide vertically between each other, and a preload spring 53 is set between them. The preload spring 53 is initially in a compressed state, so that the lower valve stem 51 always abuts against the valve core 3.

[0077] like Figure 7 As shown, a conical block 54 is provided below the lower valve stem 51;

[0078] The valve core 3 is provided with a tapered groove 33;

[0079] The conical block 54 and the conical groove 33 are fitted together.

[0080] By setting a conical block 54 at the bottom of the lower valve stem 51 and a corresponding conical groove 33 on the valve core 3, when it undergoes cold shrinkage deformation, the preload spring 53 can press the conical block 54 into the conical groove 33, ensuring that there will be no loosening between the lower valve stem 51 and the valve core 3, thereby ensuring the control accuracy of the valve stem on the valve core 3.

[0081] like Figure 8 As shown, the packing sealing mechanism 6 includes a packing gland 61, a packing assembly 62 is provided below the packing gland 61, and a sealing ring 63 is provided below the packing assembly 62.

[0082] The valve stem is sealed by setting a packing gland 61 between the valve stem and the valve body 2, and then setting a packing assembly 62 and a sealing ring 63 in sequence below the packing gland 61.

[0083] The working principle of this invention is as follows: The operator rotates the handwheel, causing the valve stem to rotate the valve core 3, thereby opening the ball valve. Low-temperature medium enters from the inlet, passing through the guide groove 22, generating a force flowing towards the center, thus reducing the impact force on the ball valve. The valve seat 41, subjected to the impact force of the medium, causes the two balance blocks 43 to slide in opposite directions within their corresponding sliding grooves 21, thereby balancing the pressure of the two balance blocks 43 and causing the adjusting plate 46 to tilt slightly, thus balancing the sealing force on the upper and lower sides of the valve seat 41. As the medium flows through, the temperature decreases, causing the originally outwardly bent outer layer 421 and inner layer 422 to gradually straighten. This causes the compensation block 42 to push the valve seat 41 towards the valve core 3, increasing the sealing force of the sealing ring 48 on the valve seat 41 against the valve core 3, thus compensating for the pressure difference. The valve core 3 and valve seat 41, due to low-temperature shrinkage deformation, have insufficient sealing force. At the same time, the elastic sealing ring 48 and the compensating spring 44 release their elastic force, ensuring that the sealing ring 48 is always tightly attached to the valve core 3, maintaining a sealed state and forming a multi-layer seal to enhance the sealing effect. The hollow valve core 3 structure reduces the shrinkage deformation. The flow channel 32, which is arc-shaped on the upper side and elliptical arc-shaped on the lower side, adjusts the medium distribution when the medium flows through the valve core 3, reducing the impact force of the medium on the lower side of the valve core 3. The pre-tightening spring 53 releases its elastic force, ensuring that the conical block 54 of the lower valve stem 51 always abuts against the conical groove 33, preventing loosening at the connection due to shrinkage deformation. By setting the packing gland 61, packing group 62 and sealing ring 63 in sequence, the gap between the valve stem and valve body 2 is sealed.

[0084] The above description is merely a preferred embodiment of the present invention. Any modifications and / or equivalent substitutions and / or improvements made within the scope of the technical solutions claimed in the claims of this application should be included within the protection scope of the present invention. The protection scope of this application is determined by the technical solutions in the claims and their equivalents, and is not limited by the specific description in the specification.

Claims

1. A cryogenic sealing compensation ball valve, the ball valve comprising an actuator (1), characterized in that: The ball valve includes a valve body (2), a valve core (3) is provided inside the valve body (2), a multi-seal mechanism (4) is provided between the valve body (2) and the valve core (3), a rotating mechanism (5) is provided on the valve core (3), a packing seal mechanism (6) is provided between the valve body (2) and the rotating mechanism (5), and the rotating mechanism (5) is connected to the actuator (1). The multi-sealing mechanism (4) includes a valve seat (41), a compensation block (42), two balance blocks (43), a compensation spring (44), an adjusting plate (46), and a sealing ring (48). The valve seat (41) provides sealing force for the sealing ring (48). The compensation block (42) is used to compensate for the sealing force of the valve seat (41). The compensation block (42) balances the sealing force on the upper and lower sides of the valve seat (41) through the two balance blocks (43). The adjusting plate (46) has two connecting rods (47) on one side. The compensation block (42) has an annular plate (45) on one side. The compensation spring (44) is located between the annular plate (45) and the valve seat (41). The balance block (43) is provided with an arc-shaped groove (431). The valve body (2) is provided with two sliding grooves (21), and the two sliding grooves (21) are connected. One end of the connecting rod (47) is provided with a protrusion (471), and the protrusion (471) is hemispherical; The valve seat (41) has an axis parallel to the direction of medium flow, the sealing ring (48) seals the valve core (3), the valve seat (41) is on the upper side near the rotating mechanism (5), the two balance blocks (43) are slidably connected to the two sliding grooves (21) respectively, the protrusion (471) is slidably connected to the arc groove (431), and the compensation block (42) is curved at the end away from the valve core (3); By setting an adjusting plate (46) at the bent end of the compensation block (42), the compensation block (42) and the adjusting plate (46) abut against each other. By setting connecting rods (47) on the upper and lower sides of the adjusting plate (46), one end of the connecting rod (47) is fixed to the adjusting plate (46), and the other end is provided with a hemispherical protrusion (471), so that the protrusion (471) abuts against the arc groove (431) of the balance block (43), thereby allowing one end of the connecting rod (47) to slide on the arc groove (431). Two connected sliding grooves (21) are provided at the upper and lower ends of the flow channel through the valve body (2). Two balance blocks (43) and two sliding grooves (21) are slidably connected. When the medium causes a greater impact on the lower side of the valve seat (41) than on the upper side of the valve seat (41), or when the sealing force is unevenly distributed due to cold shrinkage deformation on the upper and lower sides, one balance block (43) slides into the sliding groove (21), thereby pushing the hydraulic medium in the sliding groove (21) and causing the other balance block (43) to slide out of the sliding groove (21), thereby pushing the adjusting plate (46) to tilt slightly, thereby balancing the sealing force on the upper and lower sides of the valve seat (41) and preventing the lower seal from wearing much more than the upper seal.

2. The cryogenic sealing compensation ball valve according to claim 1, characterized in that: The valve seat (41) is provided with a groove (411). The compensation block (42) is provided with an outer layer (421) and an inner layer (422), wherein the coefficient of thermal expansion of the outer layer (421) is smaller than that of the inner layer (422); The sealing ring (48) is located in the groove (411), and the adjusting plate (46) and the compensation block (42) abut against each other.

3. A cryogenic sealing compensation ball valve according to claim 2, characterized in that: The compensation block (42) has a plurality of slots (423) and an arc-shaped surface (424). The arc-shaped surface (424) and the adjusting plate (46) abut against each other.

4. A cryogenic sealing compensation ball valve according to claim 1, characterized in that: The valve core (3) has a hollow groove (31) inside and a flow channel (32) on the valve core (3). The upper cross-section of the flow channel (32) is arc-shaped, and the lower cross-section of the flow channel (32) is elliptical.

5. A cryogenic sealing compensation ball valve according to claim 1, characterized in that: The valve body (2) is provided with a plurality of guide grooves (22), which are arranged in a ring and have inclined surfaces (23) on them. The angle of several of the inclined planes (23) approaching the rotating mechanism (5) gradually decreases.

6. A cryogenic sealing compensation ball valve according to claim 1, characterized in that: The rotating mechanism (5) includes a lower valve rod (51), an upper valve rod (52) is provided above the lower valve rod (51), and a preload spring (53) is provided between the lower valve rod (51) and the upper valve rod (52).

7. A cryogenic sealing compensation ball valve according to claim 6, characterized in that: A conical block (54) is provided below the lower valve stem (51); The valve core (3) is provided with a tapered groove (33); The conical block (54) and the conical groove (33) are fitted together.

8. A cryogenic sealing compensation ball valve according to claim 1, characterized in that: The packing sealing mechanism (6) includes a packing gland (61), a packing assembly (62) is provided below the packing gland (61), and a sealing ring (63) is provided below the packing assembly (62).

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