Valve stem composite seal structure and bolted gate valve with same

Abstract

The present application belongs to the technical field of gate valves, and particularly relates to a valve rod composite sealing structure and a bolt-connected gate valve with the same, which comprises a valve rod, a containing cavity is arranged between the valve rod and the upper end of a valve cover, a packing seal assembly and a pneumatic seal assembly are arranged in the containing cavity, the pneumatic seal assembly is tightly pressed on the upper end of the packing seal assembly, the upper end of the valve cover is connected with a spring gland through a screw rod assembly, a spring one is arranged between the spring gland and the pneumatic seal assembly, the packing seal assembly is located at the lower end of the pneumatic seal assembly and serves as a first reseal, when the packing seal assembly fails, the pneumatic seal assembly serves as a second reseal, further provides a sealing condition, prevents the fluid in the valve from leaking out, the packing seal assembly and the pneumatic seal assembly are constructed into a double composite sealing structure, the risk of fluid leakage in the valve is reduced, the packing seal assembly and the pneumatic seal assembly are tightly pressed in the containing cavity through the spring one, the packing seal assembly is tightly contacted with the valve rod, and the sealing performance of the valve rod is improved.

Description

Technical Field

[0001] This invention belongs to the field of gate valve technology, and particularly relates to a valve stem composite sealing structure and a bolted gate valve having the same. Background Technology

[0002] Existing gate valves only have a single packing or sealing ring between the valve cover and the valve stem, which generally results in poor sealing performance. If the packing or sealing ring fails, the fluid inside the valve body is at risk of leakage. For example, Chinese patent application number CN202111000661.0 discloses a soft-seal rising stem gate valve. The valve body is connected to the valve cover, and the valve cover is connected to the bracket. A valve plate is provided in the middle cavity of the valve body. The valve plate is wedge-shaped and consists of a main plate, sub-plates located on both sides of the main plate, and a linkage mechanism. The main plate and sub-plate are slidably engaged through the linkage mechanism. The main plate is wedge-shaped, and the slider is locked in the limiting groove and dovetail groove on both sides of the main plate. The slider has a U-shaped groove. Limiting platforms are provided on both sides of the lower end of the valve body. Two guide platforms are provided in the middle cavity of the valve body. The U-shaped grooves on the sliders located on both sides of the main plate are slidably engaged with the two guide platforms. The sub-plate consists of an inner plate and an outer plate. The outer plate has a V-shaped groove, and rubber is vulcanized on the V-shaped groove. One end of the valve shaft is connected to the main plate, and the valve shaft passes through the valve cover and the bracket in sequence. The other end of the valve shaft is connected to the handwheel. However, the disadvantage of this technical solution is that only a sealing ring is provided between the valve stem and the valve cover. The sealing effect is generally poor. If the packing or the sealing ring fails, there is a risk of fluid leakage. Summary of the Invention

[0003] The purpose of this invention is to provide a valve stem composite sealing structure and a bolted gate valve having the same, in order to solve the problems in the prior art. The specific technical solution is as follows: The valve stem composite sealing structure includes a valve stem, a receiving cavity between the valve stem and the upper end of the valve cover, a packing seal assembly and a pneumatic seal assembly inside the receiving cavity, the pneumatic seal assembly being tightly pressed against the upper end of the packing seal assembly, the upper end of the valve cover being connected to a spring cover via a screw assembly, and a spring being provided between the spring cover and the pneumatic seal assembly.

[0004] Furthermore, the packing sealing assembly includes sealing packing, a packing pad is provided between the sealing packing and the bottom of the receiving cavity, the pneumatic sealing assembly is pressed tightly against the upper end of the sealing packing, and both the packing pad and the sealing packing are slidably connected to the valve stem.

[0005] Furthermore, the pneumatic sealing assembly includes a packing gland, which is pressed tightly against the upper end of the sealing packing. The packing gland has an annular groove inside, and an annular air bladder is provided in the annular groove. Four air storage cylinders are fixedly fixed circumferentially at equal intervals on the upper end of the packing gland. The four air storage cylinders are respectively fixedly connected to the annular air bladder through four sealing rings. An annular pressure plate is slidably connected in the receiving cavity. The annular pressure plate is pressed tightly against the upper ends of the four pressure columns. A spring is provided between the annular pressure plate and the spring gland.

[0006] Furthermore, the four air storage cylinders are slidably connected to the four pressure columns respectively, and each of the four air storage cylinders and the four pressure columns is provided with a sealing ring. Each of the four air storage cylinders and the four pressure columns is provided with a sealing chamber. The four sealing chambers are respectively connected to the annular airbag through four connecting pipes. After the annular airbag is inflated, it expands and wraps around the outer wall of the valve stem.

[0007] Furthermore, the screw assembly includes two fully threaded studs, the lower ends of which are rotatably connected to two side lugs respectively. Both side lugs are fixed to the outside of the valve cover, the upper ends of which pass through the spring cover, and the upper ends of which are threadedly connected to two hexagonal nuts respectively. The lower ends of the two hexagonal nuts abut against the spring cover.

[0008] A bolted gate valve with a valve stem composite sealing structure includes a valve body, a valve cover fixed to the upper end of the valve body, and a valve stem composite sealing structure as described above provided inside the valve cover. The valve cover is connected to a handwheel assembly via two brackets.

[0009] Furthermore, the handwheel assembly includes a handwheel, a handwheel fixing plate fixed to the lower end of the handwheel, a hexagonal socket provided in the handwheel fixing plate, a valve stem threadedly connected to a rotating shaft, the middle part of the rotating shaft inserted into the hexagonal socket, the lower end of the rotating shaft rotating within a rotating shaft support frame via a bearing, a fixing nut threadedly connected to the upper end of the rotating shaft, the lower end of the fixing nut abutting against the upper end of the handwheel fixing plate, the rotating shaft support frame being fixedly connected to the valve cover via two brackets, a bearing cap pressed against the upper end of the bearing, the bearing cap being inserted into the upper end of the rotating shaft support frame, and a locking screw threadedly connected to the side of the rotating shaft support frame, the front end of the locking screw being inserted into the bearing cap.

[0010] Furthermore, both sides of the valve body and valve cover are provided with sliding grooves. Two inclined valve seats are fixed inside the valve body. Both valve seats are provided with annular grooves. A gate assembly is fixed at the lower end of the valve stem. Both ends of the gate assembly slide in the sliding grooves. After the gate assembly descends to the preset position, the two sides of the gate assembly abut against the two valve seats respectively. The two sealing airbags provided in the gate assembly are inflated and expanded respectively, and squeezed into the two annular grooves respectively.

[0011] Furthermore, the gate assembly includes a pressure block, which is fixed to the lower end of the valve stem. The pressure block is slidably connected to the upper end of the center plate. Springs are provided at both ends of the pressure block and between the pressure block and the center plate. An air storage chamber is provided between the middle of the pressure block and the center plate. A sealing ring is provided at the slidable connection between the middle of the pressure block and the center plate. The center plate is slidably connected to the slide groove through a side support frame. The air storage chamber is connected to one end of two connecting hoses through two connecting holes. The other ends of the two connecting hoses are connected to two sealing airbags through two airbag brackets. The two sealing airbags are fixed to the outside of the two gates. The two gates abut against the two valve seats.

[0012] Furthermore, T-shaped frames are fixed on both sides of the central plate, and protruding plates are fixed at both ends of the upper end of the T-shaped frames. Protruding plates are fixed on the inner sides of the two gates. T-shaped grooves are provided on the protruding plates. The T-shaped frames slide in the T-shaped grooves. A spring is provided between the protruding plate at the upper end of the T-shaped frame and the upper end of the protruding plate. The protruding plate on one gate is fixedly connected to the connecting cylinder, and the protruding plate on the other gate is fixedly connected to the insert rod. The insert rod is inserted into the connecting cylinder, and the connecting cylinder slides in the through hole provided in the central plate.

[0013] The advantages of this invention are: The packing seal assembly is located at the lower end of the pneumatic seal assembly, providing the first layer of sealing. When the packing seal assembly fails, the pneumatic seal assembly provides the second layer of sealing, further ensuring a tight seal and preventing fluid leakage from the valve. The packing seal assembly and the pneumatic seal assembly form a double composite sealing structure, reducing the risk of fluid leakage from the valve. A spring presses the packing seal assembly and the pneumatic seal assembly tightly into the receiving cavity, ensuring close contact between the packing seal assembly and the valve stem, thus increasing the sealing performance of the valve stem. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the valve stem composite sealing structure of the present invention; Figure 2 This is a schematic diagram of the bolted gate valve structure with a valve stem composite sealing structure according to the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the bolted gate valve structure with a valve stem composite sealing structure according to the present invention. Figure 2 ; Figure 4 for Figure 3 Enlarged view of a portion of point A in the middle; Figure 5 for Figure 3 Enlarged view of a section at point B in the middle; Figure 6 This is a schematic diagram of the bolted gate valve structure with a valve stem composite sealing structure according to the present invention. Figure 3 ; Figure 7 for Figure 6 Enlarged view of a section at point C; Figure 8 This is a schematic diagram of the gate assembly structure of the present invention. Figure 1 ; Figure 9 This is a schematic diagram of the gate assembly structure of the present invention. Figure 2 ; Figure 10 This is a schematic diagram of the gate assembly structure of the present invention. Figure 3 ; Figure 11 This is a schematic diagram of the valve body structure of the present invention; Explanation of markings in the diagram: 1. Valve stem; 2. Valve cover; 3. Packing gasket; 4. Sealing packing; 5. Side lug; 6. Fully threaded stud; 7. Hex nut; 8. Spring gland; 9. Spring 1; 10. Annular pressure plate; 11. Pressure column; 12. Sealing ring 1; 13. Air reservoir; 14. Connecting pipe; 15. Packing gland; 16. Annular air bladder; 17. Valve body; 18. Handwheel; 19. Handwheel fixing plate; 20. Rotary shaft; 21. Fixing nut; 22. Bearing gland; 23. Bearing; 24. Rotary shaft support frame; 25. Bracket 2 5; Slide groove 26; Valve seat 27; Annular groove 28; Locking screw 29; Gate assembly; Pressure block 30; Center plate 31; Spring II 32; Sealing ring II 33; Air storage chamber 34; Side support frame 35; Protruding plate 36; T-shaped frame 37; Spring III 38; Connecting hole 39; Gate 40; Protruding plate 41; T-shaped groove 42; Connecting hose 43; Sealing airbag 44; Airbag bracket 45; Through hole 46; Connecting cylinder 47; Insert rod 48. Detailed Implementation

[0015] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] Example 1: As Figures 1-11 As shown, the valve stem composite sealing structure includes a valve stem 1, a receiving cavity is provided between the valve stem 1 and the upper end of the valve cover 2, a packing seal assembly and a pneumatic seal assembly are provided in the receiving cavity, the pneumatic seal assembly is pressed tightly against the upper end of the packing seal assembly, the upper end of the valve cover 2 is connected to the spring cover 8 through a screw assembly, and a spring 9 is provided between the spring cover 8 and the pneumatic seal assembly. The working principle of the above technical solution is as follows: The packing seal assembly is located at the lower end of the pneumatic seal assembly, which plays the role of the first seal. When the packing seal assembly fails, the pneumatic seal assembly plays the role of the second seal, further providing sealing conditions and preventing fluid leakage from the valve. The packing seal assembly and the pneumatic seal assembly form a double composite sealing structure, which reduces the risk of fluid leakage from the valve. The packing seal assembly and the pneumatic seal assembly are pressed tightly in the receiving cavity by the spring 9, so that the packing seal assembly is in close contact with the valve stem 1, thereby increasing the sealing performance of the valve stem 1.

[0018] Example 2: Figures 1-11 As shown, the packing seal assembly includes a sealing packing 4, a packing pad 3 is provided between the sealing packing 4 and the bottom of the receiving cavity, the pneumatic seal assembly is pressed tightly on the upper end of the sealing packing 4, and both the packing pad 3 and the sealing packing 4 are slidably connected to the valve stem 1. The working principle of the above technical solution is as follows: The sealing packing 4 is clamped between the packing pad 3 and the pneumatic sealing assembly, which can keep the sealing packing 4 in a tight state, ensure that the sealing packing 4 is in close contact with the valve stem 1, prevent the fluid inside the valve from leaking out from between the sealing packing 4 and the valve stem 1, and increase the sealing performance of the valve stem 1.

[0019] Example 3: Figures 1-11 As shown, the pneumatic sealing assembly includes a packing gland 15, which is pressed tightly against the upper end of the sealing packing 4. The packing gland 15 has an annular groove, and an annular air bladder 16 is provided in the annular groove. Four air storage cylinders 13 are fixedly fixed circumferentially at the upper end of the packing gland 15. The four air storage cylinders 13 are respectively fixedly connected to the annular air bladder 16 through four sealing rings 12. An annular pressure plate 10 is slidably connected in the receiving cavity. The annular pressure plate 10 is pressed tightly against the upper end of four pressure columns 11. A spring 9 is provided between the annular pressure plate 10 and the spring gland 8. Four air storage cylinders 13 are slidably connected to four pressure columns 11 respectively. Each of the four air storage cylinders 13 and the four pressure columns 11 is provided with a sealing ring 12. Each of the four air storage cylinders 13 and the four pressure columns 11 is provided with a sealing chamber. Each of the four sealing chambers is connected to an annular air bag 16 through four connecting pipes 14. After the annular air bag 16 is inflated, it expands and wraps around the outer wall of the valve stem 1. The working principle of the above technical solution is as follows: Under the elastic force of spring 9, downward pressure is formed on the annular pressure plate 10 and the four pressure columns 11. The four pressure columns 11 slide into the four air storage cylinders 13 respectively, driving the gas in the four sealed chambers to be inflated into the annular air bag 16 through the four connecting pipes 14. The annular air bag 16 is inflated and expands and wraps around the outer wall of the valve stem 1. A seal is formed between the annular air bag 16 and the valve stem 1, preventing the fluid inside the valve from leaking out. The sealing ring 12 increases the airtightness of the sealed chamber. Under the action of spring 9, the gas in the sealed chamber can be replenished into the annular air bag 16 through the connecting pipes 14, ensuring that the annular air bag 16 is always in an inflated state and that the annular air bag 16 is wrapped around the outer wall of the valve stem 1, maintaining its good sealing performance. The four pressure columns 11 exert downward pressure on the four air storage cylinders 13 respectively. The four air storage cylinders 13 are pressed tightly on the packing gland 15. The packing gland 15 exerts downward extrusion force on the sealing packing 4, which can keep the sealing packing 4 in a tight state, ensure that the sealing packing 4 is in close contact with the valve stem 1, prevent the fluid inside the valve from leaking out from between the sealing packing 4 and the valve stem 1, and increase the sealing performance of the valve stem 1. With just spring 9, both the annular airbag 16 and the sealing packing 4 can be in close contact with the valve stem 1, achieving a double composite seal, increasing the sealing performance of the valve stem 1, and reducing the risk of fluid leakage from the valve stem 1.

[0020] Example 4: Figures 1-11 As shown, the screw assembly includes two fully threaded studs 6, the lower ends of the two fully threaded studs 6 are rotatably connected to two side lugs 5 respectively, the two side lugs 5 are fixed on the outside of the valve cover 2, the upper ends of the two side lugs 5 pass through the spring cover 8, the upper ends of the two side lugs 5 are threadedly connected to two hexagonal nuts 7 respectively, and the lower ends of the two hexagonal nuts 7 abut against the spring cover 8. The working principle of the above technical solution is as follows: the spring cover 8 is pressed tightly against the spring 9. Under the elastic force of the spring 9, the annular airbag 16 is kept in an expanded state and the sealing packing 4 is kept in a tight state, which increases the sealing performance of the valve stem 1. When the sealing performance of the valve stem 1 decreases after a period of use, the two hexagonal nuts 7 can be rotated. The two hexagonal nuts 7 squeeze the spring cover 8 down, which causes the spring 9 to be compressed. The elastic force of the spring 9 increases, which makes the annular airbag 16 expand more fully, increasing the tightness between the annular airbag 16 and the valve stem 1. At the same time, it increases the tightness between the sealing packing 4 and the valve stem 1, further increasing the sealing performance of the valve stem 1, thereby extending the service life of the valve stem 1. Turn the two hexagonal nuts 7 in opposite directions to separate the hexagonal nuts 7 from the fully threaded studs 6. The spring cover 8 can then be removed, and the spring 9 can be taken out. This allows the packing seal assembly and the pneumatic seal assembly in the receiving cavity to be removed for maintenance or replacement, which is convenient and quick. In addition, it can avoid the situation where the entire gate valve needs to be replaced due to partial damage to the gate valve.

[0021] Example 5: A bolted gate valve with a valve stem composite sealing structure, including a valve body 17, a valve cover 2 fixed to the upper end of the valve body 17, the valve cover 2 having the valve stem composite sealing structure described in any of the above, and the valve cover 2 being connected to a handwheel assembly via two brackets 25; The handwheel assembly includes a handwheel 18, a handwheel fixing plate 19 fixed at the lower end of the handwheel 18, a hexagonal socket in the handwheel fixing plate 19, a valve stem 1 threadedly connected to a rotating shaft 20, the middle part of the rotating shaft 20 inserted into the hexagonal socket, the lower end of the rotating shaft 20 rotating within a rotating shaft support frame 24 via a bearing 23, a fixing nut 21 threadedly connected to the upper end of the rotating shaft 20, the lower end of the fixing nut 21 abutting against the upper end of the handwheel fixing plate 19, the rotating shaft support frame 24 fixedly connected to the valve cover 2 via two brackets 25, a bearing cap 22 pressed against the upper end of the bearing 23, the bearing cap 22 inserted into the upper end of the rotating shaft support frame 24, a locking screw 29 threadedly connected to the side of the rotating shaft support frame 24, the front end of the locking screw 29 inserted into the bearing cap 22; The working principle of the above technical solution is as follows: Rotating the handwheel 18 drives the handwheel fixing plate 19 to rotate, which in turn drives the rotating shaft 20 to rotate. The rotating shaft 20 rotates within the rotating shaft support frame 24 through the bearing 23. The bearing 23 can reduce the friction between the rotating shaft 20 and the rotating shaft support frame 24, making the handwheel 18 easier to rotate. Since the rotating shaft 20 is threadedly connected to the valve stem 1, the rotation of the rotating shaft 20 drives the valve stem 1 to rise or fall, which in turn drives the gate assembly to rise or fall, thereby achieving the purpose of opening and closing the valve. The fixing nut 21 can be rotated off, the handwheel 18 and the handwheel fixing plate 19 can be moved up as a whole and removed from the rotating shaft 20. The locking screw 29 can be removed, and the bearing cover 22 can be removed from the rotating shaft support frame 24. The rotating shaft 20 and the bearing 23 can then be removed for maintenance or replacement, which is convenient and quick. In addition, it can avoid the situation of replacing the entire gate valve due to partial damage to the gate valve.

[0022] Example 6: Figures 1-11 As shown, both sides of the valve body 17 and the valve cover 2 are provided with sliding grooves 26. Two inclined valve seats 27 are fixed inside the valve body 17. Both valve seats 27 are provided with annular grooves 28. A gate assembly is fixed at the lower end of the valve stem 1. The two ends of the gate assembly slide in the sliding grooves 26. After the gate assembly descends to the preset position, the two sides of the gate assembly abut against the two valve seats 27 respectively. The two sealing airbags 44 provided inside the gate assembly are inflated and expanded respectively, and squeezed into the two annular grooves 28 respectively. The working principle of the above technical solution is as follows: Rotating the handwheel 18 drives the handwheel fixing plate 19 to rotate, which in turn drives the rotating shaft 20 to rotate. The rotating shaft 20 rotates within the rotating shaft support frame 24 via the bearing 23. The bearing 23 can reduce the friction between the rotating shaft 20 and the rotating shaft support frame 24, making it easier for the handwheel 18 to rotate. Since the rotating shaft 20 is threadedly connected to the valve stem 1, the rotation of the rotating shaft 20 drives the valve stem 1 to rise or fall, which in turn drives the gate assembly to rise or fall. The two ends of the gate assembly slide within the slide groove 26, ensuring the stability of the gate assembly during the rising or falling process. When the gate assembly falls to close the valve, after the gate assembly falls to the preset position, the two sides of the gate assembly abut against the two valve seats 27 respectively. The two sealing airbags 44 set inside the gate assembly are inflated and expanded, and squeezed into the two annular grooves 28 respectively, further increasing the sealing performance of the gate valve. When the gate assembly needs to rise to open the valve, the two sealing airbags 44 inside the gate assembly are deflated by air extraction. The two sealing airbags 44 separate from the two annular grooves 28 respectively. The gate assembly rises and separates from the two valve seats 27 until the gate assembly rises to the preset height, thus achieving the purpose of opening the valve.

[0023] Example 7: Figures 1-11 As shown, the gate assembly includes a pressure block 30, which is fixed to the lower end of the valve stem 1. The pressure block 30 is slidably connected to the upper end of the center plate 31. Springs 32 are provided between both ends of the pressure block 30 and the center plate 31. An air storage chamber 34 is provided between the middle of the pressure block 30 and the center plate 31. A sealing ring 33 is provided at the slidable connection between the middle of the pressure block 30 and the center plate 31. The center plate 31 is slidably connected to the slide groove 26 through a side support frame 35. The air storage chamber 34 is connected to one end of two connecting hoses 43 through two connecting holes 39. The other end of the two connecting hoses 43 is connected to two sealing airbags 44 through two airbag brackets 45. The two sealing airbags 44 are fixed to the outside of the two gates 40. The two gates 40 abut against the two valve seats 27. Both sides of the central plate 31 are fixed with T-shaped frames 37, and both ends of the upper end of the T-shaped frames 37 are fixed with protruding plates 36. The inner sides of the two gate plates 40 are fixed with protruding plates 41. The protruding plates 41 are provided with T-shaped grooves 42. The T-shaped frames 37 slide in the T-shaped grooves 42. A spring 38 is provided between the upper end of the protruding plate 36 and the upper end of the protruding plate 41 at the upper end of the T-shaped frame 37. The protruding plate 41 on one gate plate 40 is fixedly connected to the connecting cylinder 47, and the protruding plate 41 on the other gate plate 40 is fixedly connected to the insert rod 48. The insert rod 48 is inserted into the connecting cylinder 47. The connecting cylinder 47 slides in the through hole 46 provided in the central plate 31. The elastic force of the second spring 32 is greater than the elastic force of the third spring 38. The working principle of the above technical solution is as follows: When the valve needs to be closed, turn the handwheel 18, which drives the handwheel fixing plate 19 to rotate, which drives the rotating shaft 20 to rotate, causing the valve stem 1 to descend, which in turn drives the pressure block 30 and the center plate 31 to descend, causing the two gates 40 to follow the center plate 31 to descend. After the two gates 40 touch the bottom, they can no longer descend. The pressure block 30 and the center plate 31 continue to descend, and the T-shaped brackets 37 on both sides of the center plate 31 slide in the two T-shaped grooves 42 respectively, squeezing the two gates 40 to move to both ends. The two gates 40 then abut against the two valve seats 27 respectively. At this time, the two gates 40... When neither the 0 nor the center plate 31 can continue to descend, the valve stem 1 drives the pressure block 30 to continue descending. The pressure block 30 slides between the center plate 31 and the pressure block 30. The spring 32 between the pressure block 30 and the center plate 31 is compressed, and the space in the gas storage chamber 34 is compressed. The gas in the gas storage chamber 34 is squeezed into the two sealing airbags 44 through the two connecting hoses 43. The two sealing airbags 44 are inflated and squeezed into the two annular grooves 28, which increases the sealing between the valve seat 27 and the gate plate 40 and prevents the fluid in the valve body 17 from flowing freely when the gate valve is closed. After the two gates 40 touch the bottom, they separate and rest against the two valve seats 27 respectively to prevent wear between the gates 40 and the valve seats 27 and increase the service life of the gate valve. After the two gates 40 move into place, the two sealing airbags 44 are inflated to increase the sealing between the valve seats 27 and the gates 40. The above effect can be achieved simply by turning the handwheel 18 to drive the valve stem 1 down. The operation is simple and convenient. When the valve needs to be opened, turn the handwheel 18 in the opposite direction, causing the handwheel fixing plate 19 to rotate in the opposite direction, which in turn causes the rotating shaft 20 to rotate in the opposite direction, causing the valve stem 1 to rise, which in turn causes the pressure block 30 to rise. The elastic force of the second spring 32 is released, and the space of the air storage chamber 34 increases. The gas in the two sealing airbags 44 flows back into the air storage chamber 34 through the two connecting hoses 43. Both sealing airbags 44 are evacuated and deflated. The two sealing airbags 44 detach from the two annular grooves 28 respectively. The pressure block 30 continues to rise, causing the center plate 31 to rise, and the spring... When the spring force of spring 38 is released, the T-shaped frame 37 slides with the T-shaped groove 42, causing the two gate plates 40 to move together. The two gate plates 40 separate from the two valve seats 27 respectively. The valve stem 1 continues to rise, causing the pressure block 30 and the center plate 31 to rise, and causing the two gate plates 40 to rise to the preset height. By simply turning the handwheel 18, the valve stem 1 can be raised, and the sealing airbag 44 can be deflated. After the two gate plates 40 move together, they separate from each other and rise, achieving the purpose of opening the valve. The linkage is strong and the operation is simple and convenient. Sealing ring 2.33 serves a sealing function; When the center plate 31 descends, causing the two gates 40 to separate, the insert rod 48 slides outward into the connecting cylinder 47, and the connecting cylinder 47 slides upward into the through hole 46. When the center plate 31 rises, causing the two gates 40 to move together, the insert rod 48 slides inward into the connecting cylinder 47, and the connecting cylinder 47 slides downward into the through hole 46. The connecting cylinder 47 and the insert rod 48 can ensure that when the two gates 40 slide between the center plate 31 and the center plate, the two gates 40 can move synchronously, ensuring the stability of the overall movement of the gate assembly.

[0024] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A valve stem composite sealing structure, characterized in that, Includes valve stem (1), a receiving cavity is provided between the valve stem (1) and the upper end of the valve cover (2), a packing seal assembly and a pneumatic seal assembly are provided in the receiving cavity, the pneumatic seal assembly is pressed tightly against the upper end of the packing seal assembly, the upper end of the valve cover (2) is connected to the spring cover (8) through a screw assembly, and a spring (9) is provided between the spring cover (8) and the pneumatic seal assembly. The packing sealing assembly includes a sealing packing (4), a packing pad (3) is provided between the sealing packing (4) and the bottom of the receiving cavity, and the pneumatic sealing assembly is pressed tightly against the upper end of the sealing packing (4). The packing pad (3) and the sealing packing (4) are both slidably connected to the valve stem (1). The pneumatic sealing assembly includes a packing gland (15), which is pressed tightly against the upper end of the sealing packing (4). The packing gland (15) has an annular groove, and an annular airbag (16) is provided in the annular groove. Four air storage cylinders (13) are fixedly fixed at equal intervals around the upper end of the packing gland (15). The four air storage cylinders (13) are respectively fixedly connected to the annular airbag (16) through four sealing rings (12). An annular pressure plate (10) is slidably connected in the cavity. The annular pressure plate (10) is pressed tightly against the upper end of the four pressure columns (11). A spring (9) is provided between the annular pressure plate (10) and the spring gland (8). Four air storage cylinders (13) are slidably connected to four pressure columns (11) respectively. Each of the four air storage cylinders (13) and the four pressure columns (11) is provided with a sealing ring (12). Each of the four air storage cylinders (13) and the four pressure columns (11) is provided with a sealing chamber. Each of the four sealing chambers is connected to the annular air bag (16) through four connecting pipes (14). After the annular air bag (16) is inflated, it expands and wraps around the outer wall of the valve stem (1).

2. The valve stem composite sealing structure according to claim 1, characterized in that, The screw assembly includes two fully threaded studs (6), the lower ends of which are rotatably connected to two side lugs (5), both side lugs (5) are fixed on the outside of the valve cover (2), the upper ends of both side lugs (5) pass through the spring cover (8), the upper ends of both side lugs (5) are threadedly connected to two hexagonal nuts (7), and the lower ends of both hexagonal nuts (7) abut against the spring cover (8).

3. A bolted gate valve with a stem composite sealing structure, characterized in that, It includes a valve body (17), a valve cover (2) is fixed at the upper end of the valve body (17), the valve cover (2) is provided with the valve stem composite sealing structure as described in any one of claims 1-2, and the valve cover (2) is connected to the handwheel assembly through two brackets (25).

4. The bolted gate valve with a stem composite sealing structure according to claim 3, characterized in that, The handwheel assembly includes a handwheel (18), a handwheel fixing plate (19) fixed at the lower end of the handwheel (18), a hexagonal socket in the handwheel fixing plate (19), a valve stem (1) threadedly connected to a rotating shaft (20), the middle part of the rotating shaft (20) inserted into the hexagonal socket, the lower end of the rotating shaft (20) rotating in the rotating shaft support frame (24) via a bearing (23), a fixing nut (21) threadedly connected to the upper end of the rotating shaft (20), the lower end of the fixing nut (21) abutting against the upper end of the handwheel fixing plate (19), the rotating shaft support frame (24) fixedly connected to the valve cover (2) via two brackets (25), a bearing cover (22) pressed against the upper end of the bearing (23), the bearing cover (22) inserted into the upper end of the rotating shaft support frame (24), a locking screw (29) threadedly connected to the side of the rotating shaft support frame (24), the front end of the locking screw (29) inserted into the bearing cover (22).

5. The bolted gate valve with a valve stem composite sealing structure according to claim 4, characterized in that, Both sides of the valve body (17) and valve cover (2) are provided with sliding grooves (26). Two inclined valve seats (27) are fixed inside the valve body (17). Both valve seats (27) are provided with annular grooves (28). A gate assembly is fixed at the lower end of the valve stem (1). The two ends of the gate assembly slide in the sliding grooves (26). After the gate assembly descends to the preset position, the two sides of the gate assembly abut against the two valve seats (27) respectively. The two sealing airbags (44) provided inside the gate assembly are inflated and expanded respectively, and squeezed into the two annular grooves (28) respectively.

6. The bolted gate valve with a valve stem composite sealing structure according to claim 5, characterized in that, The gate assembly includes a pressure block (30), which is fixed to the lower end of the valve stem (1). The pressure block (30) is slidably connected to the upper end of the center plate (31). Springs (32) are provided between both ends of the pressure block (30) and the center plate (31). An air storage chamber (34) is provided between the middle part of the pressure block (30) and the center plate (31). A sealing ring (33) is provided at the sliding connection between the middle part of the pressure block (30) and the center plate (31). The center plate (31) is slidably connected to the slide groove (26) through the side support frame (35). The air storage chamber (34) is connected to one end of two connecting hoses (43) through two connecting holes (39). The other end of the two connecting hoses (43) is connected to two sealing airbags (44) through two airbag brackets (45). The two sealing airbags (44) are fixed to the outside of the two gates (40). The two gates (40) abut against the two valve seats (27).

7. The bolted gate valve with a valve stem composite sealing structure according to claim 6, characterized in that, T-shaped frames (37) are fixed on both sides of the center plate (31). A convex plate (36) is fixed at both ends of the upper end of the T-shaped frame (37). A convex plate (41) is fixed on the inner side of the two gate plates (40). A T-shaped groove (42) is provided on the convex plate (41). The T-shaped frame (37) slides in the T-shaped groove (42). A spring (38) is provided between the convex plate (36) at the upper end of the T-shaped frame (37) and the upper end of the convex plate (41). The convex plate (41) on one gate plate (40) is fixedly connected to the connecting cylinder (47). The convex plate (41) on the other gate plate (40) is fixedly connected to the insert rod (48). The insert rod (48) is inserted into the connecting cylinder (47). The connecting cylinder (47) slides in the through hole (46) provided in the center plate (31).

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