A self-compensating seal structure for eccentric half ball valves and rotary ball valves

Abstract

This invention provides an internal piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves, including a valve seat, valve body, sealing assembly, ball crown, and valve core. The valve seat is connected to the valve body via the sealing assembly. The ball crown is installed to the valve core, and the upper and lower ends of the valve core are rotatably connected to the valve body via connecting shafts. Rotating the valve core causes the ball crown to contact and engage with the valve seat, thus opening and closing the valve. The sealing assembly is axially movable, thereby adjusting the sealing position of the valve seat. An O-ring is provided on one side of the valve seat for sealing with the ball crown. This invention solves the technical problems of existing piston-type valve sealing structures, such as single material, poor adaptability to operating conditions, high frictional torque, weak sealing stability, cumbersome disassembly and maintenance, and short service life, by providing a modular composite piston sealing structure.

Description

Technical Field

[0001] This invention belongs to the field of valves, and in particular relates to an inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves. Background Technology

[0002] Piston-type sealing structures are the core components of valve reciprocating sealing systems. Their sealing performance, frictional characteristics, and structural stability directly determine the valve's service life and adaptability to operating conditions. Existing piston-type sealing structures have the following drawbacks: First, the sealing materials are limited. Existing structures mostly use PTFE, rubber, or pure metal seals alone. Rubber is prone to wear and aging, PTFE is easily deformed under high pressure, and metal seals have high frictional resistance. A single material is difficult to adapt to complex impurities and variable pressure conditions, resulting in high equipment leakage rates and rapid seal failure.

[0003] Secondly, the structure has poor versatility. Traditional structures are mostly customized integrated designs without standardized modular structures, and the parts cannot be interchanged, resulting in poor compatibility with different valve models.

[0004] Third, the opening and closing resistance is high. Traditional valve seats are mostly fixed structures. When under pressure, the sealing specific pressure is too high, the frictional resistance of the piston reciprocating motion increases sharply, the opening and closing torque is high, and problems such as seal wear, valve body jamming and medium leakage are prone to occur.

[0005] Fourth, the operation and maintenance costs are high. The existing structure has low integration, is cumbersome to disassemble and assemble, and vulnerable parts cannot be replaced individually. Fault repair requires complete disassembly or replacement of the entire assembly, resulting in low maintenance efficiency and high costs.

[0006] PTFE, rubber, and metal each have the advantages of low friction, high elasticity, and high rigidity and wear resistance, respectively. However, existing technologies have not achieved integrated optimization design of the three materials and piston assembly system, which cannot form a synergistic sealing effect and lack a high-performance piston sealing structure that can adapt to harsh working conditions. Invention Content In view of this, the present invention aims to propose an inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves, to solve the technical problems of existing piston valve sealing structures, such as single material, poor adaptability to working conditions, large friction torque, weak sealing stability, cumbersome disassembly and maintenance, and short service life, and to provide a modular composite piston sealing structure.

[0007] To achieve the above objectives, the technical solution created by this invention is implemented as follows: An inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves includes a valve seat, valve body, sealing assembly, ball crown, and valve core; The valve seat is connected to the valve body via a sealing assembly; the ball crown is installed on the valve core, and the upper and lower ends of the valve core are rotatably connected to the valve body via a connecting shaft. Rotating the valve core causes the ball crown to contact and cooperate with the valve seat to realize the opening and closing of the valve. The sealing assembly is axially movable, thereby enabling adjustment of the valve seat sealing position; An O-ring is provided on one side of the valve seat to achieve a seal with the ball crown.

[0008] Furthermore, the valve body has a stepped boss in the inner ring, which is a first boss and a second boss from the outside to the inside; The first boss has a plurality of first adjustment holes evenly distributed radially, and the second boss has a plurality of second adjustment holes evenly distributed radially. The first adjustment hole is a threaded through hole with an adjustment set screw inside; the second adjustment hole is a smooth through hole, and the fixing screw passes through the second adjustment hole and is threadedly connected to the valve seat to achieve the fixation between the valve seat and the valve body.

[0009] Furthermore, the valve seat adjacent to the valve body also has a stepped structure corresponding to the inner ring of the valve body. The part of the valve seat corresponding to the first boss is the first step, and the part of the valve seat corresponding to the second boss is the second step. The second step has a screw hole on its side for threaded connection with a fixing screw; The first step has a mounting hole on its side, and a sealing assembly is provided in the piston area between the mounting hole and the first boss. The sealing assembly includes a spring, a piston ring, and a star-shaped sealing ring. The spring is disposed in the mounting hole, the piston ring is disposed in the piston area, and the piston ring has annular grooves on both its inner and outer sides for fitting the star-shaped sealing ring to achieve sealing of the piston ring. The adjusting set screw can act on the piston ring to adjust the position of the piston ring; The piston rings and the star-shaped seals form the first piston.

[0010] Furthermore, rotating the fixing screw can adjust the gap between the valve seat and the valve body, and the fixing screw is fitted into the second adjustment hole, thereby allowing the valve seat to move relative to the valve body. The movable valve seat forms a second piston.

[0011] Furthermore, the gap between the second step of the valve seat and the valve body, and the gap between the piston ring and the valve body, together form the first gap.

[0012] Furthermore, a second gap is formed between the circumferential surface of the valve seat and the circumferential surface of the stepped boss of the valve body.

[0013] Compared with the prior art, the inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves described in this invention has the following advantages: (1) The present invention provides an inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves, which has excellent sealing performance and strong adaptability to working conditions. It integrates the multiple advantages of rubber elastic compensation, PTFE low friction and wear resistance, and metal rigidity and pressure resistance to form a multi-stage redundant sealing system, which solves the sealing defects of single materials. It can be adapted to working conditions containing impurities and weakly corrosive media. The leakage rate is reduced by more than 90% compared with the traditional structure, and the service life is increased by 2 to 3 times.

[0014] (2) The inner piston type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves created by the present invention has low opening and closing resistance and low operating energy consumption; the flexible adaptive sealing structure effectively reduces the piston reciprocating friction resistance.

[0015] (3) The inner piston type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves created by the present invention has a stable structure, strong impact resistance, can withstand the impact of high pressure medium, and can operate continuously for a long time without sealing failure. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of an inner piston-type self-compensating sealing structure for an eccentric hemispherical valve and a rotary ball valve, as described in an embodiment of the present invention. Figure 2 An enlarged schematic diagram of the sealing assembly described in an embodiment of the present invention; Figure 3 A schematic diagram of the positive flow working state of an inner piston-type self-compensating sealing structure for an eccentric hemispherical valve and a rotary ball valve, as described in an embodiment of the present invention. Figure 4 This is a schematic diagram of the reverse flow working state of an inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves, as described in an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Valve seat; 11. O-ring; 12. First step; 13. Second step; 2. Valve body; 21. First boss; 22. Second boss; 23. First adjusting hole; 24. Second adjusting hole; 25. Adjusting screw; 26. Fixing screw; 3. Sealing assembly; 31. Spring; 32. Piston ring; 33. Star-shaped sealing ring; 4. Ball crown; 5. Valve core; 6. First gap; 7. Second gap. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] An inner piston-type self-compensating sealing structure for eccentric ball valves and rotary ball valves, such as Figure 1 Figure 2 As shown, it includes valve seat 1, valve body 2, sealing assembly 3, ball crown 4, and valve core 5; The valve seat 1 is connected to the valve body 2 through the sealing assembly 3; the ball crown 4 is installed on the valve core 5, and the upper and lower ends of the valve core 5 are rotatably connected to the valve body 2 through the connecting shaft. Rotating the valve core 5 causes the ball crown 4 to contact and cooperate with the valve seat 1 to realize the opening and closing of the valve. The sealing assembly 3 is axially movable, thereby adjusting the sealing position of the valve seat 1; An O-ring 11 is provided on one side of the valve seat 1 for sealing with the ball crown 4.

[0023] Preferably, the inner ring of the valve body 2 is provided with stepped bosses, which are the first boss 21 and the second boss 22 from the outside to the inside; The first boss 21 has a plurality of first adjustment holes 23 evenly distributed radially, and the second boss 22 has a plurality of second adjustment holes 24 evenly distributed radially. The first adjustment hole 23 is a threaded through hole with an adjustment set screw 25 inside; the second adjustment hole 24 is a smooth through hole, and the fixing screw 26 passes through the second adjustment hole 24 and is threadedly connected to the valve seat 1 to realize the fixation between the valve seat 1 and the valve body 2.

[0024] Preferably, the valve seat 1 and the valve body 2 are adjacent to each other and are also stepped structures corresponding to the inner ring of the valve body 2. The part of the valve seat 1 corresponding to the first boss 21 is the first step 12, and the part of the valve seat 1 corresponding to the second boss 22 is the second step 13. The second step 13 has a screw hole on its side for threaded connection with the fixing screw 26; The first step 12 has a mounting hole on its side, and a sealing assembly 3 is provided in the piston area between the mounting hole and the first boss 21; The sealing assembly 3 includes a spring 31, a piston ring 32, and a star-shaped sealing ring 33. The spring 31 is disposed in the mounting hole, the piston ring 32 is disposed in the piston area, and the piston ring 32 has annular grooves on both its inner and outer sides for fitting the star-shaped sealing ring 33, thereby achieving a seal on the piston ring 32. The adjusting set screw 25 can act on the piston ring 32 to adjust the position of the piston ring 32; Piston ring 32 and star-shaped seal ring 33 form the first piston.

[0025] Preferably, rotating the fixing screw 26 can adjust the gap between the valve seat 1 and the valve body 2, and the fixing screw 26 is sleeved in the second adjusting hole 24, thereby enabling the valve seat 1 to move relative to the valve body 2; The movable valve seat 1 forms the second piston.

[0026] When the valve core experiences radial movement under pressure, the resulting second piston moves along with it. This prevents the valve core from shifting and compressing the sealing surface, thus avoiding excessive sealing pressure. The piston moves synchronously with the valve core, maintaining normal sealing performance and significantly reducing the switching torque.

[0027] Preferably, the gap between the second step 13 of the valve seat 1 and the valve body 2, and the gap between the piston ring 32 and the valve body 2, form the first gap 6.

[0028] Preferably, a second gap 7 is formed between the circumferential surface of the valve seat 1 and the circumferential surface of the stepped boss of the valve body 2.

[0029] Both the first gap 6 and the second gap 7 have adjustable spacing.

[0030] Low-friction dynamic sealing: The star-shaped sealing ring relies on the elastic tension of the rubber matrix to adhere to the inner wall of the valve body 2, achieving a long-lasting dynamic seal; Example 1: As Figure 3 As shown; Positive pressure: A8: Upstream cavity of pressurized medium (a cavity with fine graduations on the left, providing positive medium pressure); A7: Valve core-valve seat main sealing contact cone surface; A6: Provides basic preload force through elastic preload formed by springs; A5: First piston (including star-shaped seal / piston ring, locking mechanism); Overall force logic under positive compression: Positive pressure refers to the introduction of high-pressure medium into the left A8 cavity, which pushes the valve core towards the right valve seat to achieve enhanced sealing. This is a pressure self-tightening seal. 1. Medium pressure: The high-pressure medium in chamber A8 acts on the pressure-bearing surface on the left side of the valve core, generating an axial force to the right (where the medium pressure is the effective pressure-bearing area of ​​the valve core), directly pressing the valve core against the main sealing cone surface, so that the valve core and the valve seat sealing surface fit tightly together. The higher the medium pressure, the greater the contact stress on the sealing surface, and the stronger the sealing effect (pressure-assisted sealing effect). 2. A7 is the effective surface force of the medium valve seat under pressure, and A6 is the effective surface force of the medium valve seat under pressure, which is directed to the left and partially cancels out A7; the medium enters through the first gap 6 and acts on A6; 3. When there is no medium pressure, the spring at A6 maintains the initial seal of the valve core; when under positive pressure, the valve core moves to the right and further compresses the spring, increasing the spring's reaction force and forming a force balance with the medium's liquid pressure, thus ensuring a tight seal.

[0031] The elastic structure of A6 will undergo elastic deformation as the valve core is pressed: on the one hand, it absorbs the impact load and buffers the impact of pressure fluctuations on the sealing surface of A7; on the other hand, it replenishes the sealing pressure through its own rebound, compensates for the sealing relaxation caused by temperature and wear, and maintains stable contact stress on the sealing surface.

[0032] Force balance and sealing reliability Low-pressure operation: A5 spring preload force dominates the seal, ensuring no leakage at low pressure; High pressure conditions: The medium pressure dominates the compression, and A6 provides elastic compensation to adapt to a wide range of pressure sealing requirements.

[0033] Under positive pressure on surface A6, the valve seat tends to move to the right, but when the valve core is pressurized on surface A7, it also tends to move to the right, thus creating a complementary movement effect. This achieves force balance and sealing reliability, preventing excessive sealing pressure due to movement and reducing the opening and closing force. Final conclusion: When the structure is under positive pressure, it relies on the combined action of self-tightening by the medium pressure and two-stage elastic pre-tightening compensation to achieve a reliable seal between the valve seat and valve core sealing surfaces as the medium pressure increases. A5 provides basic pre-tightening, A6 provides dynamic compensation, A7 achieves main seal fit, and A8 provides a pressure source.

[0034] Example 2: As Figure 4 As shown; 1. Functions and pressure conditions of each labeled component A1: Fixing screw; connects the upper valve seat structure to the valve body. When subjected to reverse pressure, the medium pressure A1 will be pressed against the valve seat. A1 is subjected to axial load, the thrust of the medium, and the sealing force of the valve seat. The bolts and set screws are used to adjust the amount of movement.

[0035] A2: First piston; provides radial sealing to the valve stem, valve core, and valve seat assembly to prevent media leakage; When subjected to reverse pressure, the valve seat tends to move upward, A2 will be further squeezed, the radial pressure will increase, and at the same time the medium pressure will transmit the compression of spring A3, resulting in axial compression load and increasing the sealing preload.

[0036] A3. Spring; under normal conditions, it provides preload to the valve seat to ensure that the valve core fits snugly against the valve seat.

[0037] When subjected to reverse pressure, the upward thrust of the medium will compress the A3 spring. The spring bears an additional axial compressive load, resulting in increased deformation and increased elastic force. When the medium thrust exceeds the spring preload, the valve seat tends to move.

[0038] A4: The sealing surface between the valve core and the valve seat; the core cross-section of the valve, where the valve core presses against the valve seat to achieve a seal.

[0039] Reverse pressure is the core of the operating condition change: the medium acts on the valve core surface from the A4 direction, giving the valve core an upward pushing force. The original sealing tightness is canceled out, and the sealing surface changes from being pressed to being stretched open in the opposite direction. The contact pressure of the sealing surface drops significantly, and internal leakage of the medium is very likely to occur. 2. Overall reverse compression force transmission path The upward movement of the medium pressure on surface A4, the force on surface A1, and the thrust on surface A2 are transmitted through compression of spring A3, radial movement of the valve seat, and the load is transferred to the valve seat sealing pair, forming a sealing force chain in the overall structure. The valve core and seat with a bidirectional sealing structure are selected to ensure sufficient sealing pressure in both directions.

[0040] All components are arranged coaxially along the piston's central axis, forming an integrated sealed motion unit. Assembly dimensions strictly adhere to mechanical assembly standards. The entire module can be completely extracted, and each standardized component can be individually disassembled and replaced without disassembling valve body 2 or replacing the entire assembly, simplifying the maintenance process.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves, characterized in that: Includes valve seat, valve body, sealing assembly, ball crown, and valve core; The valve seat is connected to the valve body via a sealing assembly; the ball crown is installed on the valve core, and the upper and lower ends of the valve core are rotatably connected to the valve body via a connecting shaft. Rotating the valve core causes the ball crown to contact and cooperate with the valve seat to realize the opening and closing of the valve. The sealing assembly is axially movable, thereby enabling adjustment of the valve seat sealing position; An O-ring is provided on one side of the valve seat to achieve a seal with the ball crown.

2. The inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves according to claim 1, characterized in that: The valve body has a stepped boss, which consists of a first boss and a second boss from the outside to the inside. The first boss has a plurality of first adjustment holes evenly distributed radially, and the second boss has a plurality of second adjustment holes evenly distributed radially. The first adjustment hole is a threaded through hole with an adjustment set screw inside; the second adjustment hole is a smooth through hole, and the fixing screw passes through the second adjustment hole and is threadedly connected to the valve seat to achieve the fixation between the valve seat and the valve body.

3. The inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves according to claim 2, characterized in that: The valve seat adjacent to the valve body also has a stepped structure corresponding to the inner ring of the valve body. The part of the valve seat corresponding to the first boss is the first step, and the part of the valve seat corresponding to the second boss is the second step. The second step has a screw hole on its side for threaded connection with a fixing screw; The first step has a mounting hole on its side, and a sealing assembly is provided in the piston area between the mounting hole and the first boss. The sealing assembly includes a spring, a piston ring, and a star-shaped sealing ring. The spring is disposed in the mounting hole, the piston ring is disposed in the piston area, and the piston ring has annular grooves on both its inner and outer sides for fitting the star-shaped sealing ring to achieve sealing of the piston ring. The adjusting set screw can act on the piston ring to adjust the position of the piston ring; The piston rings and the star-shaped seals form the first piston.

4. The inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves according to claim 3, characterized in that: Rotating the fixing screw can adjust the gap between the valve seat and the valve body, and the fixing screw is fitted into the second adjustment hole, thereby allowing the valve seat to move relative to the valve body; The movable valve seat forms a second piston.

5. The inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves according to claim 4, characterized in that: The gap between the second step of the valve seat and the valve body, and the gap between the piston ring and the valve body, together form the first gap.

6. The inner piston-type self-compensating sealing structure for eccentric hemispherical valves and rotary ball valves according to claim 4, characterized in that: A second gap is formed between the circumferential surface of the valve seat and the circumferential surface of the stepped boss of the valve body.

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