Pressure-balanced composite sealing ball valve

Abstract

This invention discloses a pressure-balanced composite sealing ball valve, comprising a valve body, a valve stem, a valve core, and a composite sealing structure. The valve body has a fluid channel and a first mounting hole, which communicates with the fluid channel. At least a portion of the valve stem is connected to the interior of the first mounting hole, and the valve stem can be driven to rotate. The valve core is disposed inside the valve body and is movably fitted with the valve stem. The valve stem has a balance hole, and the valve core has a guide hole, which communicates with the guide hole. The composite sealing structure is fitted around the outer circumference of the valve stem and is sealed to the inner wall of the first mounting hole. When the fluid channel is open, fluid enters the first mounting hole, contacts and forces the composite sealing structure to deform axially on the valve stem. This ball valve employs a composite sealing structure, ensuring a good seal between the valve stem and valve body even under high pressure, high-frequency operation, or the penetration of small molecule media. Simultaneously, the balance hole on the valve stem reduces the operating torque of the valve stem.

Description

Technical Field

[0001] This invention relates to the field of fluid control technology, and in particular to a pressure-balanced composite sealing ball valve. Background Technology

[0002] As a key actuator in fluid control systems, ball valves are widely used in industries such as petroleum, natural gas, hydrogen refueling stations, and chemicals. Their sealing performance and structural reliability are directly related to production safety. Especially under high pressure, high frequency opening and closing conditions and when conveying small molecule gases (such as hydrogen and helium), traditional ball valves face core challenges such as sealing failure, insufficient lifespan, excessive operating torque, and low-pressure leakage during long-term operation.

[0003] Traditional ball valves often use O-rings for dynamic stem sealing. Under high pressure, high frequency operation, or the penetration of small molecule media, the O-rings are prone to wear and aging, significantly shortening their lifespan. This seriously affects the performance of the ball valve and severely impacts production safety. Furthermore, under high pressure conditions, the medium pressure forces the valve stem to move towards the packing, causing the valve stem gasket to be excessively compressed unexpectedly. This premature contact between the valve stem and the gasket results in the medium pressure acting on the entire valve stem, significantly increasing the axial force on the valve stem. This increased axial force is directly converted into friction between the valve stem and the packing, drastically increasing the operating torque required to open and close the valve core (i.e., to twist the valve stem). It also accelerates the wear of the valve stem and packing, affecting the long-term sealing stability and lifespan of the ball valve. Summary of the Invention

[0004] This invention provides a pressure-balanced composite sealing ball valve. This ball valve employs a composite sealing structure, achieving both static and dynamic sealing of the valve stem. This ensures a good seal between the valve stem and valve body even under high pressure, high-frequency operation, or the penetration of small molecule media, thereby guaranteeing production safety. Simultaneously, by incorporating a balance hole on the valve stem, this ball valve reduces the medium pressure on the valve stem, thereby reducing the valve stem operating torque and extending the service life of the valve stem gasket, thus improving the sealing stability and service life of the ball valve.

[0005] This invention provides a pressure-balanced composite sealing ball valve, comprising a valve body, a valve stem, a valve core, and a composite sealing structure;

[0006] The valve body is provided with a fluid channel and a first mounting hole, the first mounting hole is connected to the fluid channel, and the fluid channel is used to transport fluid.

[0007] At least a portion of the valve stem is connected to the interior of the first mounting hole, and the valve stem can be driven to rotate;

[0008] The valve core is disposed inside the valve body and is movably engaged with the valve stem. The valve stem is provided with a balance hole, and the valve core is provided with a flow guide hole. The balance hole and the flow guide hole are connected. The valve core can rotate with the valve stem to connect with the fluid channel, so that the flow guide hole is connected with the fluid channel, or to cut off the fluid channel.

[0009] The composite sealing structure is sleeved on the outer periphery of the valve stem and is sealed to the inner wall of the first mounting hole;

[0010] When the fluid channel is opened, the fluid passes through the guide hole and the balance hole successively and enters the first mounting hole, contacting and forcing the composite sealing structure to deform axially on the valve stem, thereby strengthening the seal between the composite sealing structure and the valve stem, and between the composite sealing structure and the inner wall of the first mounting hole.

[0011] In some embodiments, the composite sealing structure includes a plurality of first seals stacked in layers, each of the plurality of first seals being annular, and each of the first seals having a first deformation groove at its tail. The head of one of the first seals is embedded in the first deformation groove at the tail of an adjacent first seal, and the plurality of first seals are mounted on the outer periphery of the valve stem with the first deformation groove at their tails facing the valve core.

[0012] In some embodiments, the head length of the first seal closer to the valve core is longer than the head length of the first seal farther from the valve core;

[0013] The depth of the first deformation groove of the first seal member closer to the valve core is deeper than the depth of the first deformation groove of the first seal member farther from the valve core;

[0014] Furthermore, the head length of the first seal closest to the valve core is less than the depth of its first deformation groove.

[0015] In some embodiments, the head of each of the first seals is formed with a first abutting slope and a second abutting slope, the first abutting slope and the second abutting slope respectively abutting with two wall portions of the first deformation groove of the adjacent first seal, and the included angle between the first abutting slope and the second abutting slope of any one of the first seals is greater than the included angle between the two wall portions of the first deformation groove of the adjacent first seal.

[0016] In some embodiments, the composite sealing structure further includes an elastic preload member, which is also annular and is embedded in a first deformation groove of the first seal closest to the valve core. The elastic preload member is used to force the first seal to open so that the first seal seals against the inner wall of the first mounting hole when fluid pressure is removed in the first mounting hole.

[0017] In some embodiments, the elastic preload has a central connecting portion, a first serrated portion, and a second serrated portion. The central connecting portion is annular, the first serrated portion is connected to the inner side of the central connecting portion, and the second serrated portion is connected to the outer side of the central connecting portion. The central connecting portion is connected to the bottom of the first deformation groove of the corresponding first seal, and the first serrated portion and the second serrated portion are far apart from each other in the direction toward the valve core, so as to force the two walls of the corresponding first deformation groove to open.

[0018] In some embodiments, the first sawtooth portion has a plurality of spaced-apart first sawtooths, and the second sawtooth portion has a plurality of spaced-apart second sawtooths, wherein the first sawtooths and the second sawtooths are staggered in the radial direction of the valve stem, or one first sawtooth and one second sawtooth are opposite to each other in the radial direction of the valve stem.

[0019] In some embodiments, the composite sealing structure further includes a second sealing element, the second sealing element being annular, and a second deformation groove being provided at the tail end of the second sealing element. The second sealing element is disposed between two adjacent first sealing elements, and the head of the second sealing element is embedded in the first deformation groove of the adjacent first sealing element, and the head of the adjacent first sealing element is connected to the second deformation groove of the second sealing element.

[0020] The second seal is capable of deforming under fluid pressure, and the toughness of the second seal is stronger than that of the first seal.

[0021] In some embodiments, the composite sealing structure further includes a sealing base, on which a third deformation groove is provided. The sealing base is fitted around the outer periphery of the valve stem, and the head of the first sealing element furthest from the valve core is embedded in the third deformation groove.

[0022] A first step is formed in the first mounting hole, and the side of the sealing base opposite to the third deformation groove abuts against the first step.

[0023] In some embodiments, the valve stem is further provided with a diversion hole, which penetrates the valve stem radially. The balance hole is located in the middle of the valve stem and communicates with the diversion hole. When the fluid passage is opened, the fluid passes through the guide hole and the balance hole, enters the diversion hole for diversion, and flows into the composite sealing structure from the gap between the outer wall of the valve stem and the inner wall of the first mounting hole.

[0024] In some embodiments, the valve stem has a sealing mating part, a convex part and a mating part connected sequentially, and a third step is formed in the first mounting hole;

[0025] The docking part is in movable cooperation with the valve core;

[0026] A second step is formed between the convex portion and the mating portion, a first washer is fitted at the second step, and the third step receives the first washer.

[0027] The diversion hole is formed in the convex portion, and the diversion hole is offset relative to the third step;

[0028] The composite sealing structure is fitted around the outer periphery of the sealing mating part and is sealed to the inner wall of the first mounting hole.

[0029] In some embodiments, a flow guide cone is formed on the side of the third step facing the valve stem, and the flow guide cone is located on the side of the flow divider hole away from the valve core.

[0030] In some embodiments, the ratio of the inner diameter of the balancing hole to the maximum outer diameter of the mating portion is 1:(8-12).

[0031] In some embodiments, the ball valve further includes two gland assemblies, which are respectively disposed at both ends of the fluid passage;

[0032] Each of the aforementioned gland assemblies includes a gland, a valve seat, a retaining ring, and a third seal;

[0033] The valve seat abuts against the side of the valve core;

[0034] The retaining ring is fastened to the outer periphery of the valve seat;

[0035] The end of the gland has an abutment portion and a sleeve portion, the sleeve portion is formed in the middle of the abutment portion, and a step is formed between the two to allow the sleeve portion to extend into the interior of the valve seat, and the abutment portion to abut against the outer periphery of the valve seat and the retaining ring;

[0036] The third sealing element is fitted around the outer periphery of the gland and is sealed to the fluid channel.

[0037] In some embodiments, both the valve seat and the abutment portion are annular, the valve seat is provided with a circumferentially extending sealing groove, and the abutment portion is provided with a circumferentially extending sealing protrusion. The sealing protrusion is embedded in the sealing groove to seal the valve seat and the abutment portion.

[0038] In some embodiments, the ball valve further includes a plug assembly, and the valve body is provided with a second mounting hole. The second mounting hole communicates with the fluid channel, and the second mounting hole and the first mounting hole are located on opposite sides of the fluid channel in the radial direction. The plug assembly is connected to the second mounting hole to support the valve core and block the second mounting hole.

[0039] As can be seen from the above technical solutions, the present invention has the following advantages:

[0040] The valve body has a fluid channel and a first mounting hole, which communicate with the fluid channel. At least a portion of the valve stem is connected to the interior of the first mounting hole, and the valve stem can be driven to rotate. The valve core is located inside the valve body and is movablely fitted with the valve stem. The valve stem has a balance hole, and the valve core has a guide hole, which communicates with the guide hole. The valve core can rotate with the valve stem to connect with the fluid channel, allowing the guide hole to connect with the fluid channel. At this time, the ball valve is connected to the production pipeline, and the fluid in the production pipeline can be transported through the fluid channel of the ball valve. When the valve core is driven to rotate to cut off the fluid channel, the ball valve can cut off the production pipeline, thereby cutting off the fluid transport. A composite sealing structure is fitted around the outer circumference of the valve stem and is sealed to the inner wall of the first mounting hole. When the fluid channel is open, the fluid passes through the guide hole and the balance hole successively and enters the first mounting hole. The valve stem can be simultaneously subjected to... The medium pressure transmitted from the valve core and the medium pressure transmitted from the first mounting hole are balanced, resulting in a smaller axial force on the valve stem. This reduces the frictional force resisted when driving the valve stem to rotate, thus requiring less operating torque when opening or closing the valve core. This allows for easier rotation of the valve stem and reduces wear between the valve stem and its gasket, extending the service life of the valve stem gasket. Simultaneously, fluid entering the first mounting hole contacts and forces the composite sealing structure to deform axially on the valve stem, strengthening the seal between the composite sealing structure and the valve stem, as well as between the composite sealing structure and the inner wall of the first mounting hole. This ensures a good seal between the valve stem and valve body under high pressure. Furthermore, the composite sealing structure ensures a good seal between the valve stem and valve body even during high-frequency valve stem rotation or when small molecule media permeate the valve. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in this invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0042] Figure 1 This is an internal cross-sectional view of a pressure-balanced composite sealing ball valve in the open state according to an embodiment of this application;

[0043] Figure 2 yes Figure 1 The diagram shows an internal cross-sectional view of the ball valve when it is in the closed position.

[0044] Figure 3 yes Figure 1 Enlarged view of region A in the middle;

[0045] Figure 4 yes Figure 1 Enlarged view of region B in the middle;

[0046] Figure 5 yes Figure 4 Enlarged view of region C in the middle;

[0047] Figure 6 yes Figure 1 The diagram shows a structural schematic of the composite sealing structure of the ball valve.

[0048] Figure 7 yes Figure 6 An internal cross-sectional view of the composite sealing structure shown;

[0049] Figure 8 yes Figure 6 An exploded view of the components of the composite sealing structure shown;

[0050] Figure 9 yes Figure 8 The diagram shows a structural schematic of the elastic preload component of the composite sealing structure.

[0051] The meanings of the reference numerals in the attached figures are as follows:

[0052] 1. Valve body; 11. Fluid passage; 12. First mounting hole; 121. First step; 122. Third step; 122a. Guide cone surface; 13. Second mounting hole; 2. Valve stem; 21. Sealing mating part; 22. Protruding part; 221. Diverting hole; 23. Connecting part; 231. Balance hole; 24. Second step; 25. First washer; 3. Valve core; 31. Guide hole; 32. Through hole; 33. Bearing; 4. Composite sealing structure; 41. First sealing element; 411. First deformation groove; 412. Head; 412a. First abutting slope; 412b. 42. Abutting slope; 421. Elastic pre-tightening element; 422. Central connecting part; 422. First serrated part; 422a. First serrated tooth; 423. Second serrated part; 423a. Second serrated tooth; 43. Second sealing element; 431. Second deformation groove; 44. Sealing base; 441. Third deformation groove; 45. Main sealing element; 46. Secondary sealing element; 5. Gland assembly; 51. Gland; 511. Abutting part; 511a. Sealing protrusion; 512. Sleeve part; 52. Valve seat; 521. Sealing groove; 53. Protective ring; 54. Third sealing element; 6. Plug assembly; 7. Operating lever. Detailed Implementation

[0053] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0054] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0055] 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 can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] like Figures 1-4As shown, this embodiment of the invention provides a pressure-balanced composite sealing ball valve, including a valve body 1, a valve stem 2, a valve core 3, and a composite sealing structure 4. The valve body 1 is provided with a fluid channel 11 and a first mounting hole 12, the first mounting hole 12 being connected to the fluid channel 11, and the fluid channel 11 being used to transport fluid. At least a portion of the valve stem 2 is connected to the interior of the first mounting hole 12, and the valve stem 2 can be driven to rotate. The valve core 3 is disposed inside the valve body 1 and is movably fitted with the valve stem 2. The valve stem 2 is provided with a balance hole 231, and the valve core 3 is provided with a guide hole 31, the balance hole 231 being connected to the guide hole 31. The valve core 3 can rotate with the valve stem 2 to connect with the fluid channel 11, so that the guide hole 31 is connected to the fluid channel 11, or to cut off the fluid channel 11. The composite sealing structure 4 is sleeved on the outer periphery of the valve stem 2 and is sealed to the inner wall of the first mounting hole 12.

[0057] When the fluid channel 11 is opened, the fluid passes through the guide hole 31 and the balance hole 231 and enters the first mounting hole 12, contacting and forcing the composite sealing structure 4 to deform in the axial direction of the valve stem 2, so as to strengthen the seal between the composite sealing structure 4 and the valve stem 2, and between the composite sealing structure 4 and the inner wall of the first mounting hole 12.

[0058] Based on the above technical solution, at least a portion of the valve stem 2 is connected to the interior of the first mounting hole 12. The valve stem 2 can be driven to rotate, and the valve core 3 can rotate with the valve stem 2 to communicate with the fluid channel 11, so that the guide hole 31 is connected to the fluid channel 11. At this time, the ball valve is connected to the production pipeline, and the fluid in the production pipeline can be transported through the fluid channel 11 of the ball valve. When the valve core 3 is driven to rotate to cut off the fluid channel 11, the ball valve can cut off the production pipeline and thus cut off the fluid transport. The composite sealing structure 4 is sleeved on the outer periphery of the valve stem 2 and is sealed to the inner wall of the first mounting hole 12. When the fluid channel 11 is opened, the fluid enters the first mounting hole 12 through the guide hole 31 and the balance hole 231. The valve stem 2 can simultaneously receive the medium pressure transmitted from the valve core 3 and the medium pressure transmitted from the first mounting hole 12. The medium pressures at these two locations are mutually... The balance ensures a smaller axial force on the valve stem 2, resulting in less friction when driving the valve stem 2 to rotate. This reduces the operating torque applied to the valve stem 2 when opening or closing the valve core 3, allowing operators to easily rotate the valve stem 2 and simultaneously reducing wear between the valve stem 2 and its gasket, thus extending the service life of the valve stem 2 gasket. Simultaneously, fluid entering the first mounting hole 12 contacts and forces the composite sealing structure 4 to deform axially on the valve stem 2, strengthening the seal between the composite sealing structure 4 and the valve stem 2, and between the composite sealing structure 4 and the inner wall of the first mounting hole 12. This achieves a good seal between the valve stem 2 and the valve body 1 under high pressure. Furthermore, the composite sealing structure 4 ensures a good seal between the valve stem 2 and the valve body 1 even when the valve stem 2 is rotated at high frequency or when small molecule media permeate, thereby guaranteeing production safety.

[0059] Therefore, this ball valve adopts a composite sealing structure 4, which can achieve both static and dynamic sealing of the valve stem 2. This ensures a good seal between the valve stem 2 and the valve body 1 under high pressure, high frequency operation, or the penetration of small molecule media, thereby guaranteeing production safety. At the same time, by setting a balance hole 231 on the valve stem 2, this ball valve can reduce the medium pressure on the valve stem 2, reduce the operating torque of the valve stem 2, and extend the service life of the valve stem 2 gasket, thereby improving the sealing stability and service life of the ball valve.

[0060] The valve core 3 has a through hole 32 inside. One end of the valve stem 2 that extends out of the first mounting hole 12 is connected to an operating rod 7. The operator can twist the operating rod 7 to drive the valve stem 2 to rotate, thereby driving the valve core 3 to rotate. When the through hole 32 inside the valve core 3 is connected to the fluid channel 11, the fluid channel 11 is open. When the through hole 32 inside the valve core 3 is not connected to the fluid channel 11, the fluid channel 11 is cut off.

[0061] This ball valve can be used in production pipelines that transport high and low pressure media. When the ball valve is connected to the production pipeline—the fluid channel 11 is connected to the production pipeline—when the pressure in the production pipeline is low, the pre-tightening force provided by the composite sealing structure 4 can achieve the sealing of the valve stem 2 and the valve body 1. The pre-tightening force here is formed when the valve stem 2 and the valve body 1 jointly squeeze the composite sealing structure 4 at the beginning of assembly. When the pressure in the production pipeline is high, the fluid can enter the first mounting hole 12. The high-pressure fluid will contact and force the composite sealing structure 4 to deform, thereby enhancing its sealing between the valve stem 2 and the inner wall of the first mounting hole 12, i.e., the valve body 1, to avoid leakage of fluid from the sealing position between the valve stem 2 and the valve body 1 due to the increase in fluid pressure.

[0062] Thus, this ball valve can adapt to both high and low pressure media, and can achieve reliable sealing under all operating conditions from low pressure to high pressure, so as to ensure production safety.

[0063] Specifically, such as Figures 6-9 As shown, the composite sealing structure 4 includes multiple first sealing elements 41 stacked in layers. Each of the multiple first sealing elements 41 is annular and can be fitted onto the outer periphery of the valve stem 2. Each of the first sealing elements 41 has a first deformation groove 411 at its tail. The head 412 of one first sealing element 41 is embedded in the first deformation groove 411 at the tail of the adjacent first sealing element 41. All of the multiple first sealing elements 41 are installed on the outer periphery of the valve stem 2 with their tail first deformation grooves 411 facing the valve core 3.

[0064] When the valve core 3 is driven to rotate to open the fluid passage 11, the medium enters the first mounting hole 12 through the fluid passage 11, the guide hole 31, and the balance hole 231. At this time, the fluid will first contact and enter the first deformation groove 411 on the first seal 41. The first deformation groove 411 closest to the valve core 3 is the first one to contact. As a result, the fluid will force the two walls of the first deformation groove 411 to deform, causing the two walls of the first deformation groove 411 to unfold. The inner wall will form a stronger abutment with the valve stem 2, thereby strengthening the seal between the inner and outer walls. A stronger abutment is formed between the wall portion and the inner wall of the first mounting hole 12, thereby strengthening the seal between the wall portion and the inner wall of the first mounting hole 12, i.e., the valve body 1. Furthermore, the greater the fluid pressure, the greater the extent to which the two walls of the first deformation groove 411 expand, and the stronger the sealing effect between the groove and the valve stem 2 and the valve body 1. Under the pressure of the fluid, the first deformation grooves 411 of the multiple first sealing elements 41 expand to different degrees. The multiple first sealing elements 41 work together to seal layer by layer, ensuring a good seal between the valve stem 2 and the inner wall of the first mounting hole 12, i.e., the valve body 1, to strictly ensure production safety.

[0065] Multiple first seals 41 are stacked in layers, with the head 412 of one first seal 41 embedded in the first deformation groove 411 at the tail of the adjacent first seal 41. In this way, under the action of fluid pressure, these multiple first seals 41 will be connected more tightly, and a relatively strong stress will be formed between them to resist the fluid pressure. This avoids that individual first seals 41 will be severely damaged under the impact of fluid pressure when the valve core 3 is opened or closed for a long time, thus affecting the overall sealing effect of the composite sealing structure 4.

[0066] Under normal circumstances, when the valve core 3 is driven to rotate to open the fluid passage 11, the fluid will quickly enter the first mounting hole 12 from the guide hole 31 on the valve core 3 and the balance hole 231 in the docking part 23 of the valve stem 2, and contact the composite sealing structure 4. At this time, the first seal 41 that is closer to the valve core 3 is subjected to a stronger impact, and the first seal 41 that is closest to the valve core 3 is subjected to the strongest impact. During the long-term operation of turning the valve stem 2 to open and close this ball valve, these first seals 41 will be subjected to the impact of the fluid again and again. In order to avoid excessive wear of these first seals 41 under the impact of the fluid, the shape of the first seals 41 needs to be redesigned.

[0067] The head 412 of the first seal 41 refers to the portion from the bottom wall of the first deformation groove 411 to the other end face of the first seal 41.

[0068] In some embodiments, the length of the head 412 of the first seal 41 near the valve core 3 is longer than the length of the head 412 of the first seal 41 away from the valve core 3, the depth of the first deformation groove 411 of the first seal 41 near the valve core 3 is deeper than the depth of the first deformation groove 411 of the first seal 41 away from the valve core 3, the length of the head 412 of the first seal 41 closest to the valve core 3 is less than the depth of its first deformation groove 411, and the thickness of each wall portion of the first deformation groove 411 of the first seal 41 near the valve core 3 is greater than or equal to the thickness of the wall portion of the first deformation groove 411 of the first seal 41 away from the valve core 3. Thus, the first seal 41 near the valve core 3 is stronger and more resistant to fluid pressure shocks than the first seal 41 away from the valve core 3.

[0069] Based on this, the head 412 of each first seal 41 is formed with a first abutting slope 412a and a second abutting slope 412b. The first abutting slope 412a and the second abutting slope 412b respectively abut against the two walls of the first deformation groove 411 of the adjacent first seal 41. Furthermore, the included angle between the first abutting slope 412a and the second abutting slope 412b of any first seal 41 is greater than the included angle between the two walls of the first deformation groove 411 of the adjacent first seal 41. Under the impact of fluid pressure, the first abutting slope 412a and the second abutting slope 412b at the head 412 of a first seal 41 are in contact with the wall surface of the first deformation groove 411 at the tail of the adjacent first seal 41, and a strong stress is formed between them, so that they do not easily separate, thereby ensuring the structural strength between them, thus effectively resisting fluid pressure and preventing excessive wear.

[0070] As a preferred embodiment, the angle between the first abutting slope 412a and the second abutting slope 412b of any one of the first sealing elements 41 is 80° to 120°. When the medium pressure acts on the composite sealing structure 4, the angle between the first abutting slope 412a and the second abutting slope 412b of the head 412 of the first sealing element 41 determines the uniformity of its deformation direction and mechanical properties. Each first sealing element 41 transmits pressure according to the same geometric rules (axial compression and radial expansion), ensuring that the force transmission path in the multi-layer composite sealing structure 4 is consistent and predictable.

[0071] The included angle between the first abutting inclined surface 412a and the second abutting inclined surface 412b of any one of the first sealing elements 41 is greater than the included angle between the two walls of the first deformation groove 411 of the adjacent first sealing element 41 by 10° to 15°. Due to the 10° to 15° angle difference, the two adjacent first sealing elements 41 will initially form a clear line contact at the head or tail. This line contact area is extremely small, and under the same preload, it can generate extremely high local contact stress, making it very easy to be compressed and sealed. Thus, a reliable initial seal can be achieved under extremely low pressure. Furthermore, when the pressure of the fluid medium is high, the medium pressure pushes the first seal. The first seal 41 deforms and expands backward (axially away from the valve core 3) and outward (radially towards the valve stem 2). During the deformation process, the wall of the first deformation groove 411 of the first seal 41 will gradually achieve a more complete and tighter fit with the first abutting inclined surface 412a / second abutting inclined surface 412b of the adjacent first seal 41. This deformation process is adaptive. The greater the pressure, the larger and tighter the fitting area. This is equivalent to reserving space and directional guidance for the high-pressure deformation of the first seal 41, so that its sealing force increases smoothly and stably with the increase of pressure, avoiding stress mutation and excessive wear caused by fluid impact.

[0072] The composite sealing structure 4 of this ball valve is suitable for sealing under low-pressure conditions and can also prevent the penetration and leakage of small molecule media such as hydrogen molecules.

[0073] The composite sealing structure 4 also includes an elastic pre-tightening element 42, which is also annular. The elastic pre-tightening element 42 is embedded in the first deformation groove 411 of the first sealing element 41 closest to the valve core 3. The elastic pre-tightening element 42 is used to force the first sealing element 41 to open so that when the fluid pressure is removed in the first mounting hole 12, or when the ball valve is connected to a low-pressure production pipeline, the first sealing element 41 seals with the inner wall of the first mounting hole 12, thereby preventing fluid medium leakage and achieving a seal between the valve stem 2 and the valve body 1 under low-pressure conditions.

[0074] When the medium pressure is too high, the elastic preload 42 can also deform like the first seal 41, and the elastic preload 42 and the first seal 41 assembled therewith can deform together, and the two unfold to the same degree, thereby ensuring the seal between the valve stem 2 and the valve body 1 under high pressure.

[0075] In some embodiments, the elastic pretensioner 42 has a central connecting portion 421, a first serrated portion 422, and a second serrated portion 423. The central connecting portion 421 is annular, the first serrated portion 422 is connected to the inner side of the central connecting portion 421, and the second serrated portion 423 is connected to the outer side of the central connecting portion 421. The central connecting portion 421 is connected to the bottom of the first deformation groove 411 of the corresponding first seal 41, and the first serrated portion 422 and the second serrated portion 423 are far apart from each other in the direction toward the valve core 3, so as to force the two walls of the corresponding first deformation groove 411 to open.

[0076] The first sawtooth portion 422 has a plurality of spaced first sawtooths 422a, and the second sawtooth portion 423 has a plurality of spaced second sawtooths 423a. The first sawtooths 422a and the second sawtooths 423a are staggered in the radial direction of the valve stem 2, or one first sawtooth 422a and one second sawtooth 423a are opposite to each other in the radial direction of the valve stem 2.

[0077] The shape of the elastic preload 42 is designed in two ways: first, so that when the composite sealing structure 4 is assembled on the valve stem 2, the elastic preload 42 can abut the two walls of the first deformation groove 411 of the first sealing element 41 to which it is assembled abut against the valve stem 2 and the valve body 1 respectively, ensuring a seal between the valve stem 2 and the valve body 1 under low-pressure conditions; second, so that under the pressure of the medium, the elastic preload 42 can produce a similar deformation to the first sealing element 41 to which it is assembled, with the same degree of expansion and the same direction of deformation, and so that each subsequent first sealing element 41 follows the same geometric rules (compression in the axial direction and radial direction of the valve stem 2). The upward expansion is used to transmit pressure, ensuring that the force is transmitted along a consistent path in the composite sealing structure 4. This allows the sealing force of the composite sealing structure 4 to increase smoothly and stably with the increase of pressure, achieving adaptive sealing under high-pressure conditions. In addition, the shape of the elastic preload 42 is designed in this way, giving it good fatigue resistance and tightness in connection with the first deformation groove 411 of the first sealing element 41. It only needs to be installed in the first deformation groove 411 of the first sealing element 41 in an embedded form. Under high pressure, it can automatically adhere to the first deformation groove 411 without the need for additional processes to make the two fit together.

[0078] In some embodiments, the composite sealing structure 4 further includes a second sealing element 43, which is annular and has a second deformation groove 431 at its tail. The second sealing element 43 is disposed between two adjacent first sealing elements 41, and the head of the second sealing element 43 is embedded in the first deformation groove 411 of the adjacent first sealing element 41. The head 412 of the adjacent first sealing element 41 is connected to the second deformation groove 431 of the second sealing element 43. The second sealing element 43 is deformable under the drive of fluid pressure, and the toughness of the second sealing element 43 is stronger than that of the first sealing element 41.

[0079] The shape of the second seal 43 is similar to that of the adjacent first seal 41, and it is also stacked between two adjacent first seals 41.

[0080] The composite sealing structure 4 includes multiple first sealing elements 41. The closest first sealing element 41 can be used as the main sealing element 45, and the remaining first sealing elements 41 can be used as secondary sealing elements 46. The elastic pre-tightening element 42 is assembled in the first deformation groove 411 of the main sealing element 45, and the second sealing element 43 is disposed between two adjacent secondary sealing elements 46.

[0081] The main seal 45 provides the main sealing function.

[0082] The secondary seal 46 provides support, cushioning, and impermeability to prevent leakage of small molecule media.

[0083] The second seal 43 provides cushioning and protection to the main seal located in front of it (the side closer to the valve core 3), and provides "pressure equalization" and "isolation" to the main seal located behind it (the side farther from the valve core 3).

[0084] When the high-pressure medium pushes the main seal 45 to deform backward, the second seal 43, which is in direct contact with it, undergoes elastic deformation due to its good toughness, absorbing part of the impact energy. This avoids the excessively rigid support body causing local "hardening" on the main seal 45, preventing the main seal 45 from accelerating wear or undergoing cold flow (plastic deformation) due to stress concentration, thereby protecting the integrity and long-term sealing performance of the main seal 45. Furthermore, the second seal 43 redistributes the uneven pressure from the front through its own deformation, transforming it into a more uniform load that is transmitted to the secondary seal 46 behind. This protects the rear components from point impacts, ensuring that the entire composite sealing structure 4 can move backward and compact as a whole under high pressure, rather than collapsing locally. At the same time, the second seal 43 also isolates the fretting friction that may occur due to the difference in thermal expansion coefficients between the front and rear materials.

[0085] In addition, the second seal 43 is made of RPTFE and other materials. RPTFE is a type of reinforced polytetrafluoroethylene, which has good sealing properties and better creep resistance. When placed in the middle, it serves as an auxiliary sealing barrier. Due to the higher mechanical strength brought by the reinforcing fibers, it can effectively resist the tendency of high-pressure media to "squeeze" it into the sealing gap, thus improving the stability of the entire composite sealing structure 4 under high pressure. The toughness of the second seal 43 is stronger than that of the secondary seal 46. Through the gradient design of material mechanical properties, the composite sealing structure 4 achieves the effect of "flexibility with rigidity and rigidity combined", enabling the composite sealing structure 4 to work stably and for a long service life under all high and low pressure conditions.

[0086] Under the impact of medium pressure, the composite sealing structure 4 tends to move away from the valve core 3. At this time, the composite sealing structure 4 needs to form an abutment with the wall of the first mounting hole 12 to limit the displacement of the composite sealing structure 4 in the axial direction of the valve stem 2. If the composite sealing structure 4 and the valve stem 2 form an abutment in the axial direction, the pressure of the high-pressure medium will act on the valve stem 2 through the composite sealing structure 4, which will also cause the valve stem 2 to be subjected to a strong axial force, making the operating torque of the valve stem 2 larger. This will not only make it difficult to turn the valve stem 2, but will also cause the valve stem 2 gasket to wear excessively.

[0087] Specifically, the composite sealing structure 4 also includes a sealing base 44, on which a third deformation groove 441 is provided. The sealing base 44 is fitted around the outer periphery of the valve stem 2, and the head 412 of the first sealing member 41 furthest from the valve core 3 is embedded in the third deformation groove 441. A first step 121 is formed in the first mounting hole 12, and the side of the sealing base 44 away from the third deformation groove 441 abuts against the first step 121.

[0088] The sealing base 44 is assembled in the same way as the multiple first seals 41 and second seals 43. This allows the fluid pressure to be transmitted to the sealing base 44 through the multiple first seals 41 and second seals 43 without generating a component force deviating from the axial direction, thus preventing the valve stem 2 from being difficult to rotate. The first step 121 can restrict the axial displacement of the sealing base 44, thereby allowing the first seals 41 and second seals 43 to undergo axial compression and radial expansion to seal the valve stem 2 and the valve body 1.

[0089] As a preferred option, the first seal 41 is made of reinforced PTFE material (i.e., reinforced polytetrafluoroethylene), the elastic preload 42 is made of stainless steel, and the sealing base 44 is made of PEEK material (polyether ether ketone).

[0090] The elastic preload 42 provides initial sealing force, pressure adaptation, and wear compensation.

[0091] The main seal 45 in the first seal 41 provides the main sealing function, has excellent corrosion resistance and self-lubricating properties, and can reduce the contact friction between it and the valve stem 2 and the valve body 1.

[0092] The foreground secondary seal 46 and the second seal 43 provide coordinated support and cushioning to ensure the morphological stability of the main seal 45.

[0093] The rearward-positioned sub-seal 46 and seal base 44 provide rigid support and an ultimate impermeability barrier.

[0094] When the system pressure is low or in the initial state, the sealing effect of the composite sealing structure 4 mainly relies on the pre-tightening force of the elastic pre-tightening element 42. The elastic tension of the elastic pre-tightening element 42 will radially expand the first sealing element 41 (main sealing element 45) so that it fits tightly against the sealing surface to form an initial seal. At this time, the secondary sealing element 46 and the second sealing element 43 work together to provide lateral support for the main sealing element 45, ensuring that its sealing effect is stable and will not fail under low pressure.

[0095] When the system pressure increases, the medium pressure penetrates deep into the composite sealing structure 4 and acts on the back of the main seal 45. At this time, the thrust generated by the medium pressure and the elastic force of the elastic pre-tightening member 42 form a combined force, which further strengthens the fit between the wall of the first deformation groove 411 of the main seal 45 and the sealing surface, forming a self-reinforcing effect of "the higher the medium pressure, the tighter the seal". At the same time, the secondary seal 46 and the sealing base 44 at the rear can effectively buffer the high pressure impact and provide the ultimate resistance for the entire sealing system to prevent medium leakage.

[0096] like Figures 3-5 As shown, a balance hole 231 is provided on the valve stem 2, which can guide the high-pressure medium on one side of the valve stem 2 to the other side, thereby establishing a dynamic pressure balance zone on the upper and lower or both sides of the valve stem 2. This design ensures that even under high pressure, the axial force of the medium acting on the valve stem 2 can be largely canceled out, reducing the friction between the valve stem 2 and the packing, making the valve operation easier and more flexible, and avoiding abnormal wear of the valve stem 2 and the first gasket 25 under high pressure. This significantly extends the service life of the valve stem 2 and the first gasket 25, and improves the reliability of the valve under long-term high-frequency operation. At the same time, the optimized stress state ensures that the valve stem 2 seal always works within a controllable design range, avoiding seal failure or structural damage caused by excessive stress, ensuring sealing stability throughout the entire life cycle. Furthermore, the integrated bottom valve stem 2 combined with the balance hole 231 design fundamentally eliminates the risk of the valve stem 2 flying out, thus substantially improving the safety performance of this ball valve.

[0097] When the fluid channel 11 is opened, the fluid enters the balance hole 231 through the guide hole 31. At this time, the fluid pressure is relatively strong. In order to reduce the fluid velocity and pressure, a diversion hole 221 is also provided on the valve stem 2. The diversion hole 221 penetrates the valve stem 2 in the radial direction. The balance hole 231 is located in the middle of the valve stem 2 and communicates with the diversion hole 221. When the fluid channel 11 is opened, the fluid enters the diversion hole 221 through the guide hole 31 and the balance hole 231 and is diverted. At this time, the fluid flow... The flow rate is slowed down, the fluid pressure decreases, and the fluid flows out from the diversion hole 221. Instead, it flows into the contact composite sealing structure 4 through the gap between the outer wall of the valve stem 2 and the inner wall of the first mounting hole 12. Because the gap between the outer wall of the valve stem 2 and the inner wall of the first mounting hole 12 is small, the flow rate of the fluid is greatly slowed down, and the fluid pressure is significantly reduced. This prevents the fluid from causing excessive impact on the composite sealing structure 4 when it comes into contact with it, thus avoiding excessive wear and tear on the composite sealing structure 4.

[0098] The valve stem 2 has a sealing mating part 21, a convex part 22, and a docking part 23 connected sequentially. A third step 122 is formed in the first mounting hole 12. The docking part 23 is movablely mated with the valve core 3. When opening or closing the valve core 3, the operator can twist the valve stem 2 via the operating lever 7, so that the docking part 23 of the valve stem 2 drives the valve core 3 to rotate, so that the through hole 32 on the valve core 3 is connected to the fluid channel 11, thereby opening the fluid channel 11. Specifically, the specific way in which the docking part 23 is movablely mated with the valve core 3 can adopt existing known docking methods, which will not be described in detail here.

[0099] A second step 24 is formed between the convex part 22 and the mating part 23. A first washer 25 is fitted onto the second step 24. A third step 122 receives the first washer 25. By setting the third step 122 in the first mounting hole 12, the axial displacement of the valve stem 2 can be restricted. In conjunction with the first washer 25, the valve stem 2 can rotate circumferentially to open or close the valve core 3.

[0100] A diversion hole 221 is provided in the convex part 22. The diversion hole 221 is offset from the third step 122. The distance between the area of ​​the non-diversion hole 221 on the convex part 22 and the step surface of the third step 122 is extremely short. The gap between them is extremely small, so as to effectively slow down the flow rate of the fluid at this point and reduce the impact of the fluid on the composite sealing structure 4 when it comes into contact with it.

[0101] The composite sealing structure 4 is fitted around the outer periphery of the sealing mating part 21 and is sealed to the inner wall of the first mounting hole 12.

[0102] In some embodiments, a flow guide cone 122a is formed on the side of the third step 122 facing the valve stem 2. The flow guide cone 122a is located on the side of the diversion hole 221 away from the valve core 3. At the moment when the fluid channel 11 is opened or cut off, there is an extremely high local pressure difference between the valve core 3 and the valve stem 2. When the fluid comes out from the diversion hole 221, it will directly contact the flow guide cone 122a. The flow guide cone 122a can guide the fluid to transition smoothly, significantly reducing the impact pressure and "adsorption effect" of the fluid on the valve stem 2. When the ball valve is quickly closed under high pressure differential conditions, the flow guide cone 122a can guide the fluid to gradually decelerate, avoiding the fluid kinetic energy from being instantly converted into pressure shock waves, thereby protecting the valve stem 2 from vibration.

[0103] In some embodiments, the ratio of the inner diameter of the balance hole 231 to the maximum outer diameter of the mating portion 23 is 1:(8-12). This ratio range ensures that the balance hole 231 has sufficient flow cross-sectional area, effectively guiding the pressure at the mating portion 23 of the valve stem 2 to the low-pressure side, significantly reducing the net axial force on the valve stem 2. This not only greatly reduces the friction between the valve stem 2 and the first washer 25, reducing the valve opening and closing torque, but also improves the action response sensitivity of the valve stem 2, avoiding the "jamming" phenomenon under high pressure differential conditions. Furthermore, compared to an excessively large balance hole 231, this ratio range constrains the upper limit of the diameter of the balance hole 231, ensuring... The section modulus of the valve stem 2 body is optimized so that the deflection deformation of the valve stem 2 can be controlled within a low range when subjected to torque and lateral load. This effectively suppresses the mechanical vibration and uneven wear of the sealing surface of the valve under high-speed fluid, and improves the operational stability under high-pressure conditions. In addition, the size of the balance hole 231 corresponding to this ratio range forms a moderate flow resistance characteristic, which avoids the problems of excessive throttling effect and pressure balance lag caused by too small a hole diameter, and avoids the problems of too low medium flow rate and sediment blockage of the flow channel caused by too large a hole diameter. This optimization makes the balance hole 231 have self-cleaning flow field characteristics when the valve is in operation with trace impurities.

[0104] This ball valve also includes two gland assemblies 5, which are correspondingly disposed at both ends of the fluid channel 11. Each gland assembly 5 includes a gland 51, a valve seat 52, a retaining ring 53, and a third sealing element 54. The valve seat 52 abuts against the side of the valve core 3 to support the valve core 3. The two valve seats 52 work together to restrict the position of the valve core 3 and prevent the valve core 3 from shifting under the impact of the fluid. The retaining ring 53 is tightened around the outer periphery of the valve seat 52 to support and protect the valve seat 52, preventing deformation of the valve seat 52, which would cause the valve core 3 to shift, resulting in local high pressure in the fluid channel 11 and affecting the structural stability and sealing effect of components such as the valve stem 2. The gland 51 is internally perforated and screwed onto the end of the fluid channel 11. The gland 51 can be axially adjusted relative to the fluid channel 11. The connection end of the production pipeline can be connected to the gland. The ball valve is connected to the production pipeline via a 51 connection. When the fluid channel 11 is opened, the production pipeline is also opened, allowing fluid to be transmitted. The end of the gland 51 has an abutment portion 511 and a sleeve portion 512. The sleeve portion 512 is formed in the middle of the abutment portion 511, and a step is formed between the two to allow the sleeve portion 512 to extend into the interior of the valve seat 52, and the abutment portion 511 to abut against the outer periphery of the valve seat 52 and the retaining ring 53. Thus, a relatively stable structure is formed between the gland 51, the valve seat 52, and the retaining ring 53 to ensure that the valve seat 52 can stably support the valve core 3. At the same time, these three will not be misaligned under the impact of the fluid. The third seal 54 is fitted around the outer periphery of the gland 51 and is sealed to the fluid channel 11. The third seal 54 can prevent fluid from leaking from the gap between the gland 51 and the fluid channel 11.

[0105] The third sealing element 54 can be an O-ring or other similar component.

[0106] Both the valve seat 52 and the abutment portion 511 are annular. The valve seat 52 is provided with a circumferentially extending sealing groove 521, and the abutment portion 511 is provided with a circumferentially extending sealing protrusion 511a. The sealing protrusion 511a is embedded in the sealing groove 521 to seal the valve seat 52 and the abutment portion 511.

[0107] When the system pressure is low, the mechanical pre-tightening force applied by the gland 51 causes the sealing protrusion 511a at its end to generate sufficient initial contact stress with the sealing groove 521 of the valve seat 52, ensuring the immediate effectiveness of the low-pressure seal.

[0108] When the system pressure increases, the medium pressure enters a specific chamber on the back of the valve seat 52. This pressure acts on the effective pressure-bearing area of ​​the valve seat 52, generating an additional axial thrust proportional to the medium pressure. This thrust is converted into a radial clamping force through the spherical surface, driving the valve seat 52 to press more tightly against the valve core 3, forming a self-reinforcing effect of "the higher the pressure, the tighter the seal," which greatly improves the sealing reliability of the valve under high-pressure conditions. Furthermore, the sealing protrusion 511a at the end of the gland 51 and the sealing groove 521 of the valve seat 52 achieve radial self-tightening. Under high pressure, the medium pressure further strengthens the fit between the gland 51 and the valve seat 52, thereby achieving a good seal. In addition, the valve seat 52, the retaining ring 53, and the gland 51 adopt a modular integrated design, which effectively reduces the connection interface, reduces the risk of leakage, and improves assembly and maintenance efficiency.

[0109] In some embodiments, the ball valve further includes a plug assembly 6, and the valve body 1 is also provided with a second mounting hole 13. The second mounting hole 13 communicates with the fluid channel 11, and the second mounting hole 13 and the first mounting hole 12 are respectively located on opposite sides of the fluid channel 11 in the radial direction. The plug assembly 6 is connected in the second mounting hole 13 to support the valve core 3 and block the second mounting hole 13.

[0110] Bearings 33 are provided in both the first mounting hole 12 and the second mounting hole 13. Both ends of the valve core 3 are connected to the inside of the bearings 33, thus ensuring that the valve core 3 can be driven to rotate smoothly.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A pressure balanced, composite seated ball valve characterized by, The valve body, the valve stem, the valve core and the composite sealing structure are included. The valve body is provided with a fluid passage and a first mounting hole, the first mounting hole is communicated with the fluid passage, and the fluid passage is used for conveying fluid. At least part of the valve stem is connected to the inside of the first mounting hole, and the valve stem can be driven to rotate. The valve core is arranged in the inside of the valve body and is movably connected with the valve stem, the valve stem is provided with a balance hole, the valve core is provided with a flow guide hole, the balance hole is communicated with the flow guide hole, wherein the valve core can rotate with the valve stem to open or cut off the fluid passage. The composite sealing structure is sleeved on the outer periphery of the valve stem and is sealingly connected with the inner side wall of the first mounting hole. When the fluid passage is opened, the fluid enters the first mounting hole through the flow guide hole and the balance hole in sequence, contacts and forces the composite sealing structure to deform in the axial direction of the valve stem, so as to respectively strengthen the sealing between the composite sealing structure and the valve stem and the sealing between the composite sealing structure and the inner side wall of the first mounting hole.

2. The pressure balanced, composite seated ball valve of claim 1, wherein, The composite sealing structure includes a plurality of first sealing members stacked one by one, each of the first sealing members is annular, and the tail of each of the first sealing members is provided with a first deformation groove, wherein the head of one of the first sealing members is embedded in the first deformation groove of the tail of the first sealing member adjacent thereto, and each of the first sealing members is installed on the outer periphery of the valve stem with the first deformation groove of the tail thereof facing the valve core.

3. The pressure balanced, multi-seal, globe valve of claim 2, wherein, The length of the head of the first sealing member close to the valve core is longer than the length of the head of the first sealing member away from the valve core. The depth of the first deformation groove of the first sealing member close to the valve core is deeper than the depth of the first deformation groove of the first sealing member away from the valve core. The length of the head of the first sealing member closest to the valve core is less than the depth of the first deformation groove thereof.

4. The pressure balanced, multi-seal, globe valve of claim 2, wherein, The head of each of the first sealing members is formed with a first abutting inclined surface and a second abutting inclined surface, the first abutting inclined surface and the second abutting inclined surface are respectively abutted with two wall portions of the first deformation groove of the first sealing member adjacent thereto, and the included angle between the first abutting inclined surface and the second abutting inclined surface of any one of the first sealing members is greater than the included angle between the two wall portions of the first deformation groove of the first sealing member adjacent thereto.

5. The pressure balanced, composite seated ball valve according to any one of claims 2-4, characterized in that, The composite sealing structure further includes an elastic pre-tightening member, the elastic pre-tightening member is also annular, the elastic pre-tightening member is embedded in the first deformation groove of the first sealing member closest to the valve core, and the elastic pre-tightening member is used to force the first sealing member to open, so that the first sealing member is sealed with the inner side wall of the first mounting hole when the fluid pressure in the first mounting hole is removed.

6. The pressure balanced, multi-seal, globe valve of claim 5, wherein, The elastic pre-tightening member has a middle connecting portion, a first sawtooth portion and a second sawtooth portion, the middle connecting portion is annular, the first sawtooth portion is connected to the inner side of the middle connecting portion, and the second sawtooth portion is connected to the outer side of the middle connecting portion, wherein the middle connecting portion is connected to the bottom of the first deformation groove of the corresponding first sealing member, and the first sawtooth portion and the second sawtooth portion are away from each other in the direction towards the valve core, so as to force the two wall portions of the corresponding first deformation groove to be opened.

7. The pressure balanced, multi-seal, globe valve of claim 6, wherein, The first sawtooth portion has a plurality of first sawteeth arranged at intervals, and the second sawtooth portion has a plurality of second sawteeth arranged at intervals, wherein the first sawteeth and the second sawteeth are staggered in the radial direction of the valve rod, or one first sawtooth and one second sawtooth are opposite in the radial direction of the valve rod.

8. The pressure balanced, multi-seal, globe valve of claim 5, wherein, The composite sealing structure further comprises a second sealing member, the second sealing member is annular, the tail portion of the second sealing member is also provided with a second deformation groove, the second sealing member is arranged between two adjacent first sealing members, and the head portion of the second sealing member is embedded in the first deformation groove of the first sealing member adjacent thereto, and the second deformation groove of the second sealing member accesses the head portion of the first sealing member adjacent thereto. Wherein the second sealing member can be deformed under the driving of fluid pressure, and the toughness of the second sealing member is stronger than that of the first sealing member.

9. The pressure balanced, multi-seal, globe valve of claim 5, wherein, The composite sealing structure further comprises a sealing base, the sealing base is provided with a third deformation groove, the sealing base is sleeved on the outer periphery of the valve rod, and the head portion of the first sealing member farthest from the valve core is embedded in the third deformation groove. A first step is formed in the first mounting hole, and the side of the sealing base away from the third deformation groove abuts against the first step.

10. The pressure balanced, multi-seal, globe valve of claim 1, wherein, The valve rod is further provided with a shunt hole, the shunt hole penetrates the valve rod in the radial direction of the valve rod, the balance hole is arranged in the middle portion of the valve rod and communicates with the shunt hole, wherein when the fluid channel is conducted, the fluid enters the shunt hole through the flow guide hole and the balance hole, and flows into the composite sealing structure from the gap between the outer side wall of the valve rod and the inner side wall of the first mounting hole.

11. The pressure balanced, composite seated ball valve of claim 10, wherein, The valve rod has a sealing fitting portion, a convex portion and a butt joint portion connected in sequence, and a third step is formed in the first mounting hole. The butt joint portion movably cooperates with the valve core. A second step is formed between the convex portion and the butt joint portion, a first gasket is sleeved on the second step, and the third step receives the first gasket. The shunt hole is arranged in the convex portion and is staggered relative to the third step. The composite sealing structure is sleeved on the outer periphery of the sealing fitting portion and is sealingly connected with the inner side wall of the first mounting hole.

12. The pressure balanced, composite seated ball valve of claim 11, wherein, A flow guide conical surface is formed on the side of the third step facing the valve rod, and the flow guide conical surface is located on the side of the shunt hole away from the valve core.

13. The pressure balanced, multi-seal, globe valve of claim 11, wherein, The ratio of the inner diameter of the balance hole to the maximum outer diameter of the butt joint portion is 1: (8-12).

14. The pressure balanced, multi-seal, globe valve of claim 1, wherein, The ball valve also includes two gland assemblies, which are respectively disposed at both ends of the fluid channel; Each of the aforementioned gland assemblies includes a gland, a valve seat, a retaining ring, and a third seal; The valve seat abuts against the side of the valve core; The retaining ring is fastened to the outer periphery of the valve seat; The end of the gland has an abutment portion and a sleeve portion, the sleeve portion is formed in the middle of the abutment portion, and a step is formed between the two to allow the sleeve portion to extend into the interior of the valve seat, and the abutment portion to abut against the outer periphery of the valve seat and the retaining ring; The third sealing element is fitted around the outer periphery of the gland and is sealed to the fluid channel.

15. The pressure balanced, multi-port seal ball valve of claim 14, wherein, Both the valve seat and the abutment portion are annular. The valve seat is provided with a circumferentially extending sealing groove, and the abutment portion is provided with a circumferentially extending sealing protrusion. The sealing protrusion is embedded in the sealing groove to seal the valve seat and the abutment portion.

16. The pressure balanced, multi-seal, globe valve of claim 1, wherein, The ball valve also includes a plug assembly, and the valve body is provided with a second mounting hole. The second mounting hole communicates with the fluid channel, and the second mounting hole and the first mounting hole are located on opposite sides of the fluid channel in the radial direction. The plug assembly is connected in the second mounting hole to support the valve core and block the second mounting hole.

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