A semiconductor vacuum plug-in valve and sealing method thereof

Abstract

The present invention discloses a semiconductor vacuum gate valve, wherein the valve stem comprises an outer valve stem and an inner valve stem, the outer valve stem being sleeved on the outer side of the inner valve stem and being movably and hermetically connected to the valve body; the inner valve stem and the outer valve stem are both connected to a driving device; the inner cavity of the valve body is located on the outer side of the valve stem and is provided with a bellows assembly, one side of the bellows assembly being connected to the valve body and the other side being connected to a connecting plate on the outer valve stem; the valve core assembly comprises a valve plate and a valve core frame, the valve plate not being in contact with the bottom of the inner cavity of the valve body; a movement cavity is provided in the valve core frame, and openings are provided on both sides of the movement cavity; a connecting rod is fixedly connected to one side of the valve plate, the connecting rod is movably and hermetically connected to the opening, and one side of the connecting rod passes through the opening and is located in the movement cavity, and a disc spring is provided on the side of the connecting rod located in the movement cavity; one side of the inner valve stem is located inside the movement cavity; a clamping plate is also provided in the movement cavity, one side of the clamping plate being connected to the connecting rod and the other side being connected to the inner valve stem. This design can prevent the gate valve from contaminating wafers.

Description

Technical Field

[0001] The invention belongs to the technical field of gate valves, and in particular relates to a semiconductor vacuum gate valve. Background Art

[0002] A vacuum gate valve uses an actuator to raise and lower the valve core assembly (consisting of a drive frame, push rod, and sealing plate) to open and close the valve. When the valve is closed, the sealing plate moves to the sealing position and stops, while the drive frame continues to move. The push rod connected between the sealing plate and the drive frame pushes the sealing plate away from the drive body and presses against the sealing surface of the valve body. When the push rod is horizontal, the pressing force reaches maximum, and the valve is fully closed. When the valve is opened, the drive frame moves away from the sealing area, and the push rod forces the sealing plate backward. After disengaging from the valve body sealing surface, it moves with the drive body until the valve is fully opened. Vacuum gate valves offer high flow capacity, compact structure, small size, light weight, and thinness. They are widely used in high-tech fields such as electronics, chemical engineering, metallurgy, nuclear industry, aviation, aerospace, materials, biomedicine, atomic energy, and space exploration.

[0003] In semiconductor production in the electronics field, the generation of fine particles must be strictly prevented throughout the wafer transportation process. The main components involved in the wafer transportation process are the transfer system, vacuum valves, and the planetary motion disk below the wafer. The transfer system robot is located below the wafer, so even if contaminated particles are generated, they are unlikely to fall directly on the wafer. The wafers in the wafer cassette that transports the wafers need to pass directly through the vacuum valve when moving to the processing equipment station with a vacuum environment. If fine particles are generated by friction or collision during the movement of the vacuum valve, or if the vacuum valve itself has particles attached to the valve surface above the wafer, the particles are likely to fall directly on the surface of the wafer as it passes through the valve, resulting in a decrease in the yield rate.

[0004] Patent application number CN202122325756.1 discloses a semiconductor vacuum gate valve comprising a valve body, a cover plate, a support frame, a drive mechanism, a valve stem, and a valve plate. The side wall of the valve body is provided with a valve opening, and the cover plate seal is located on the top opening of the valve body in the non-passage direction. The support frame is connected to the upper portion of the cover plate, and the drive mechanism is connected to the support frame. The cover plate is provided with a through hole, one end of the valve stem is connected to the output end of the drive mechanism, and the other end of the valve stem extends through the through hole in the cover plate into the inner cavity of the valve body. The valve plate is used to seal the valve opening. A bellows sleeved around the outer circumference of the valve stem is sealed between the valve stem and the cover plate. A gate valve with this structure cannot effectively ensure the cleanliness of a vacuum environment. Summary of the Invention

[0005] The present invention aims to provide a semiconductor vacuum gate valve to address the problem mentioned in the background art that particles generated during the movement of existing vacuum gate valves are easily dropped onto wafers. A semiconductor vacuum gate valve sealing method is also disclosed.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A semiconductor vacuum gate valve comprises a valve body, a valve stem and a valve core assembly, wherein the valve body is provided with an air inlet and an air outlet, the valve stem is used to push the valve core assembly to block the air inlet and the air outlet, the valve stem comprises an outer valve stem and an inner valve stem, the outer valve stem is sleeved on the outer side of the inner valve stem and is movably and sealingly connected to the valve body; the inner valve stem and the outer valve stem are both connected to a driving device;

[0008] The inner cavity of the valve body is located outside the valve stem and is provided with a bellows assembly. One side of the bellows assembly is connected to the valve body and the other side is connected to the connecting plate on the outer valve stem. The valve core assembly includes a valve plate and a valve core frame. The valve plate does not contact the bottom of the inner cavity of the valve body. The valve core frame is fixedly connected to the connecting plate on the outer valve stem. A movement cavity is provided in the valve core frame, and openings are provided on both sides of the movement cavity.

[0009] A connecting rod is fixedly connected to one side of the valve plate, the connecting rod is movably sealed with the opening, and one side of the connecting rod passes through the opening and is located in the motion chamber, and a disc spring is provided on the side of the connecting rod located in the motion chamber; one side of the inner valve stem is located inside the motion chamber; a clamping plate is also provided in the motion chamber, one side of the clamping plate is connected to the connecting rod, and the other side is connected to the inner valve stem.

[0010] Furthermore, a return cavity is provided in the outer valve stem, and a spring is provided in the return cavity. One side of the spring is connected to the bottom of the return cavity, and the other side is connected to the inner valve stem.

[0011] Furthermore, the driving device adopts a cylinder, and a large piston and a small piston are arranged in the cylinder, wherein the large piston is connected to the outer valve stem, and the small piston is connected to the inner valve stem.

[0012] Furthermore, a first sealing groove is provided on one side of the valve plate, and a sealing ring is provided in the first sealing groove.

[0013] Furthermore, a guide cylinder is provided on the outer side of the valve core frame at the opening position.

[0014] Furthermore, a second sealing groove is provided inside the outer valve stem near the bottom, and a sealing ring is provided in the second sealing groove.

[0015] Furthermore, a clamping groove with a right-angled triangle cross-section is provided near the bottom of the inner valve stem, and one side of the clamping plate is clamped in the clamping groove.

[0016] A semiconductor vacuum plug-in valve sealing method, including a primary sealing method, a secondary sealing method and a tertiary sealing method;

[0017] Primary sealing method: The bellows group in the valve body is fixedly sealed with the top of the valve body, and the bottom of the bellows group is fixedly sealed with the connecting plate on the outer valve stem. The top of the valve body, the bellows group and the connecting plate form a primary sealing space, wherein the position where the outer valve stem and the valve body move relative to each other is located in the primary sealing space, and the position where the outer valve stem and the inner valve stem move relative to each other is also located in the primary sealing space;

[0018] Secondary sealing method: The movement space inside the valve core frame forms a second sealing space, and the valve plate is connected to the card plate through a connecting rod, and the inner valve stem and the valve plate are connected to the card plate through a connecting rod. The inner valve stem and the card plate are movably connected, and the movement of the inner valve stem can push the card plate closer to or away from the connecting rod; the second sealing space is used to wrap the connection between the inner valve stem and the card plate, and at the same time wrap the connection between the card plate and the connecting rod;

[0019] Three-level sealing method: when the outer valve stem drives the valve core frame to move toward the bottom of the valve body, it moves until the bellows group extends to the limit length, and the inner valve stem moves downward. The inner valve stem moves downward to squeeze the card plate, causing the card plate to rotate. The rotated card plate squeezes the connecting rod, and the connecting rod drives the valve plate to seal the air inlet or outlet; after the valve plate blocks the air inlet or outlet, there is a gap between the bottom of the valve plate and the bottom of the valve body, and there is a gap between the bottom of the valve core frame and the bottom inside the valve body.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention utilizes an inner valve stem and an outer valve stem to jointly propel the valve plate and seal the air inlet or outlet. To prevent particles generated by friction between the valve stem and the valve body from contaminating wafers, a bellows assembly and a valve core holder are designed. The bellows assembly and valve core holder can accommodate particles, effectively preventing particles generated by friction between components within the valve body from affecting wafer production.

[0022] To achieve step-by-step control of the outer and inner valve stems, a large piston and a small piston are provided. A spring is placed between the outer and inner valve stems, providing a certain initial force to ensure that the inner valve stem initially moves with the outer valve stem. The large piston then pushes the outer and inner valve stems to move together, and finally the small piston pushes the inner valve stem to move, thus achieving step-by-step movement and facilitating the installation of the valve plate at the bottom of the valve stem.

[0023] The inner valve stem and the outer valve stem are driven upward by the driving device. In the initial stage, under the action of the spring force of the disc spring, the disc spring drives the connecting rod to reset, thereby separating the valve plate from the air inlet and the air outlet, and then the inner valve stem and the outer valve stem move upward together.

[0024] During the entire process of closing or opening the valve, the valve disc will not rub against the inner wall of the valve body. The valve disc is designed not to contact the bottom of the valve body to prevent friction between the valve disc and the valve body.

[0025] The design of the valve core frame forms a sealed space between the inner valve stem, the clamping plate and the connecting rod. Particles generated by friction between the inner valve stem and the outer valve stem or by squeezing the clamping plate will fall into this sealed space.

[0026] The bellows assembly wraps the outer valve stem to form a sealed space, and particles generated by friction of the outer valve stem will fall into this sealed space. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 for Figure 1 A local enlarged schematic diagram of point A;

[0029] Figure 3 for Figure 1 A partial enlarged schematic diagram of point B.

[0030] Markings in the figure: 1-valve body, 2-air inlet, 3-valve plate, 4-inner valve stem, 5-outer valve stem, 6-bellows group, 7-connecting plate, 8-sealing ring, 9-air outlet, 10-connecting rod, 11-valve core frame, 12-movement chamber, 14-clamping plate, 15-guide cylinder, 16-disc spring, 17-sealing ring, 18-return chamber, 19-spring, 20-large piston, 21-cylinder, 22-small piston. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example

[0032] A semiconductor vacuum gate valve includes a valve body 1, a valve stem, and a valve core assembly. The valve body 1 is provided with an air inlet 2 and an air outlet 9. The valve stem is used to push the valve core assembly to block the air inlet 2 and the air outlet 9. The valve stem includes an outer valve stem 5 and an inner valve stem 4. The outer valve stem 5 is sleeved on the outside of the inner valve stem 4 and is movably and sealingly connected to the valve body 1. The inner valve stem 4 and the outer valve stem 5 are both connected to a driving device.

[0033] The inner cavity of the valve body 1 is located outside the valve stem and is provided with a bellows assembly 6. One side of the bellows assembly 6 is connected to the valve body 1 and the other side is connected to the connecting plate 7 on the outer valve stem 5. The valve core assembly includes a valve plate 3 and a valve core frame 11. The valve plate 3 does not contact the bottom of the inner cavity of the valve body 1. The valve core frame 11 is fixedly connected to the connecting plate 7 on the outer valve stem 5. A movement chamber 12 is provided in the valve core frame 11, and openings are provided on both sides of the movement chamber 12.

[0034] A connecting rod 10 is fixed to one side of the valve plate 3, and the connecting rod 10 is movably sealed and connected to the opening. One side of the connecting rod 10 passes through the opening and is located in the motion chamber 12. A disc spring 16 is provided on the side of the connecting rod 10 located in the motion chamber 12; one side of the inner valve stem 4 is located inside the motion chamber 12; a clamping plate 14 is also provided in the motion chamber 12, and one side of the clamping plate 14 is connected to the connecting rod 10, and the other side is connected to the inner valve stem 4.

[0035] In actual use, when the valve needs to be closed, the driving device pushes the inner valve stem 4 and the outer valve stem 5 downward. Since the inner valve stem 4 squeezes the retaining plate 14 when it moves downward, the retaining plate 14 pushes the connecting rod 10 after being squeezed. The connecting rod 10 is preloaded by the disc spring 16. In the initial stage, the inner valve stem 4 does not move relative to the outer valve stem 5, and the inner valve stem 4 and the outer valve stem 5 move downward at the same time. When the outer valve stem 5 moves to the elongation limit of the bellows assembly 6, the outer valve stem 5 is stuck. The driving device continues to push the inner valve stem 4, and the inner valve stem 4 begins to move downward and squeezes the retaining plate 14. The retaining plate 14 pushes the connecting rod 10. After overcoming the preload of the disc spring 16, the connecting rod 10 moves outward. The connecting rod 10 drives the valve plate 3 to move outward to seal the air inlet 2 and the air outlet 9.

[0036] When the valve needs to be opened, the drive mechanism drives the inner valve stem 4 and outer valve stem 5 upward. Initially, the spring force 19 of the disc spring 16 causes the connecting rod 10 to reset, separating the valve plate 3 from the air inlet 2 and the air outlet 9. Subsequently, the inner valve stem 4 and outer valve stem 5 move upward together. This design prevents friction between the valve plate 3 and the inner wall of the valve body 1 during the entire process of closing or opening the valve. The valve plate 3 is designed to avoid contact with the bottom of the valve body 1, also to prevent friction between the valve plate 3 and the valve body 1. The design of the valve core frame 11 creates a sealed space between the inner valve stem 4, the retaining plate 14, and the connecting rod 10. Particles generated by friction between the inner valve stem 4 and the outer valve stem 5, or by compression of the retaining plate 14, fall into this sealed space. The bellows assembly 6 encloses the outer valve stem 5, creating a sealed space into which particles generated by friction with the outer valve stem 5 fall. The above-mentioned various designs can effectively prevent particles generated during the mechanical movement of the gate valve from contaminating the wafer.

[0037] The present invention provides an inner valve stem 4 and an outer valve stem 5, which work together to push the valve plate 3 to move and seal the air inlet 2 or the air outlet 9. To prevent particles generated by friction between the valve stem and the valve body 1 from contaminating the wafer, a bellows assembly 6 and a valve core frame 11 are designed. The bellows assembly 6 and the valve core frame 11 can accommodate particles, thereby effectively preventing particles generated by friction between components on the valve body from affecting wafer production.

[0038] In a preferred embodiment, a return cavity 18 is provided within the outer valve stem 5, and a spring 19 is disposed within the return cavity 18. One side of the spring 19 is connected to the bottom of the return cavity 18, and the other side is connected to the inner valve stem 4. The spring 19 can exert a certain preload force on the inner valve stem 4, thereby preventing the inner valve stem 4 from moving downward during the initial descent phase and rebounding during the initial ascent phase, thereby effectively preventing friction between the valve plate 3 and the valve body 1.

[0039] In a preferred embodiment, the driving device adopts a cylinder 21, in which a large piston 20 and a small piston 22 are disposed. The large piston 20 is connected to the outer valve stem 5, and the small piston 22 is connected to the inner valve stem 4. The design of the large piston 20 and the small piston 22 enables the inner valve stem 4 and the outer valve stem 5 to be driven by a cylinder 21. High-pressure gas is introduced into the cylinder 21. In the initial stage, the gas will push the large piston 20 and the outer valve stem 5 to move. After the outer valve stem 5 and the large piston 20 have completed their movement, the high-pressure gas will drive the small piston 22 and the inner valve stem 4 to move.

[0040] In a preferred embodiment, a first sealing groove is provided on one side of the valve plate 3, and a sealing ring 8 is provided in the first sealing groove. The sealing ring 8 is a rubber sealing ring 8. The provision of the sealing ring 8 can improve the sealing performance of the valve plate 3, thereby effectively blocking the air inlet 2 and the air outlet 9.

[0041] In a preferred embodiment, a guide cylinder 15 is provided on the outer side of the valve core frame 11 at the opening position. The design of the guide cylinder 15 can facilitate the movement of the connecting rod 10, so that the connecting rod 10 moves more smoothly.

[0042] In a preferred embodiment, a second sealing groove is provided near the bottom of the outer valve stem 5, and a sealing ring 17 is provided in the second sealing groove. The sealing ring 17 is a rubber sealing ring 17, and the design of the sealing ring 17 can improve the sealing performance between the inner valve stem 4 and the outer valve stem 5.

[0043] In a preferred embodiment, a slot with a right-angled triangle cross-section is provided near the bottom of the inner valve stem 4, and one side of the card plate 14 is clamped in the slot. When the connecting rod 10 is not pushed, the card plate 14 fits in with the right-angled side of the slot. When the connecting rod 10 is pushed, that is, the inner valve stem 4 squeezes the card plate 14, at this time the card plate 14 fits in with the oblique side of the slot. This design limits the position of the card plate 14, ensuring the stability of the movement of the card plate 14. A semiconductor vacuum plug-in valve sealing method, including a primary sealing method, a secondary sealing method, and a tertiary sealing method;

[0044] Primary sealing method: The bellows assembly 6 in the valve body 1 is fixedly sealed and connected to the top of the valve body 1. The bottom of the bellows assembly 6 is fixedly sealed and connected to the connecting plate 7 on the outer valve stem 5. The top of the valve body 1, the bellows assembly 6 and the connecting plate 7 form a primary sealing space. The position where the outer valve stem 5 and the valve body 1 move relative to each other is located in the primary sealing space, and the position where the outer valve stem 5 and the inner valve stem 4 move relative to each other is also located in the primary sealing space.

[0045] During the initial stage of valve closing or the latter half of valve opening, friction occurs between the outer valve stem 5 and the valve body 1. This friction can easily form fine particles. Since the inner cavity of the valve body 1 is connected to the system at the valve opening, these particles can easily enter the system and contaminate the wafers. This method utilizes the bellows assembly 6, which can contain the particles and effectively prevent them from leaking into the inner cavity of the valve body 1.

[0046] Secondary sealing method: The movement chamber 12 inside the valve core frame 11 forms a second sealed space, and the valve plate 3 is connected to the clamping plate 14 through the connecting rod 10, and the inner valve stem 4 and the valve plate 3 are connected to the clamping plate 14 through the connecting rod 10. The inner valve stem 4 and the clamping plate 14 are movably connected, and the movement of the inner valve stem 4 can push the clamping plate 14 closer to or away from the connecting rod 10; the second sealed space is used to wrap the connection between the inner valve stem 4 and the clamping plate 14, and at the same time wrap the connection between the clamping plate 14 and the connecting rod 10;

[0047] The secondary sealing method can collect particles generated after the inner valve stem 4 contacts the clamping plate 14 through the second sealed space and ensure that the particles are stored in the second sealed space, that is, in the valve core frame 11 .

[0048] Three-level sealing method: when the outer valve stem 5 drives the valve core frame 11 to move toward the bottom of the valve body 1, it moves until the bellows group 6 extends to the limit length, and the inner valve stem 4 moves downward. The inner valve stem 4 moves downward to squeeze the card plate 14, causing the card plate 14 to rotate. The rotated card plate 14 squeezes the connecting rod 10, and the connecting rod 10 drives the valve plate 3 to seal the air inlet 2 or the air outlet 9; after the valve plate 3 blocks the air inlet 2 or the air outlet 9, there is a gap between the bottom of the valve plate 3 and the bottom of the valve body 1, and there is a gap between the bottom of the valve core frame 11 and the bottom inside the valve body 1.

[0049] In order to prevent the valve stem from rubbing against the valve body 1 when pushing the valve plate 3 to open outward, an outer valve stem 5 and an inner valve stem 4 are designed, wherein the connecting rod 10 on the valve plate 3 is movably connected to the valve core frame 11 at the bottom of the outer valve stem 5. The movement of the valve plate 3 can be controlled by pushing the inner valve stem 4. Therefore, the design of the outer valve stem 5 and the inner valve stem 4 will prevent the valve plate 3 from rubbing against the valve body 1 in the process of blocking the air inlet 2 and the air outlet 9, thereby effectively reducing the generation of particles in the valve body 1, thereby effectively ensuring the cleanliness of the wafers in the system.

[0050] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0052] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A semiconductor vacuum plug-in valve, comprising a valve body (1), a valve stem and a valve core assembly, wherein the valve body (1) is provided with an air inlet (2) and an air outlet (9), and the valve stem is used to push the valve core assembly to block the air inlet (2) and the air outlet (9), and is characterized in that: The valve stem comprises an outer valve stem (5) and an inner valve stem (4), wherein the outer valve stem (5) is sleeved on the outer side of the inner valve stem (4) and is movably and hermetically connected to the valve body (1); the inner valve stem (4) and the outer valve stem (5) are both connected to a driving device; a return cavity (18) is provided in the outer valve stem (5), a spring (19) is provided in the return cavity (18), one side of the spring (19) is connected to the bottom of the return cavity (18), and the other side is connected to the inner valve stem (4); The inner cavity of the valve body (1) is located on the outer side of the valve stem and is provided with a bellows group (6). One side of the bellows group (6) is connected to the valve body (1) and the other side is connected to the connecting plate (7) on the outer valve stem (5). The bellows group (6) wraps the outer valve stem (5) to form a sealed space; the valve core assembly includes a valve plate (3) and a valve core frame (11), and the valve plate (3) does not contact the bottom of the inner cavity of the valve body (1); the valve core frame (11) is fixedly connected to the connecting plate (7) on the outer valve stem (5), and a movement cavity (12) is provided in the valve core frame (11), and openings are provided on both sides of the movement cavity (12); the valve core frame (11) forms a sealed space between the inner valve stem (4), the clamping plate (14) and the connecting rod (10); A connecting rod (10) is fixedly connected to one side of the valve plate (3), the connecting rod (10) is movably sealedly connected to the opening, and one side of the connecting rod (10) passes through the opening and is located in the movement chamber (12), and a disc spring (16) is provided on the side of the connecting rod (10) located in the movement chamber (12); one side of the inner valve stem (4) is located inside the movement chamber (12); a clamping plate (14) is also provided in the movement chamber (12), one side of the clamping plate (14) is connected to the connecting rod (10), and the other side is connected to the inner valve stem (4); a clamping groove with a right triangle cross section is provided near the bottom of the inner valve stem (4), and one side of the clamping plate (14) is clamped in the clamping groove.

2. The semiconductor vacuum gate valve according to claim 1, characterized in that: The driving device adopts a cylinder (21), and a large piston (20) and a small piston (22) are arranged in the cylinder (21), wherein the large piston (20) is connected to the outer valve stem (5), and the small piston (22) is connected to the inner valve stem (4).

3. The semiconductor vacuum gate valve according to claim 1, characterized in that: A first sealing groove is provided on one side of the valve plate (3), and a sealing ring (8) is provided in the first sealing groove.

4. The semiconductor vacuum gate valve according to claim 1, characterized in that: A guide cylinder (15) is provided on the outer side of the valve core frame (11) at the opening position.

5. The semiconductor vacuum gate valve according to claim 1, characterized in that: A second sealing groove is provided at a position near the bottom of the inner portion of the outer valve stem (5), and a sealing ring (17) is provided in the second sealing groove.

6. A method for sealing a semiconductor vacuum gate valve, using the semiconductor vacuum gate valve according to any one of claims 1 to 5, characterized in that: Including primary sealing method, secondary sealing method and tertiary sealing method; Primary sealing method: the bellows group (6) in the valve body (1) is fixedly sealed and connected to the top of the valve body (1), the bottom of the bellows group (6) is fixedly sealed and connected to the connecting plate (7) on the outer valve stem (5), the top of the valve body (1), the bellows group (6) and the connecting plate (7) constitute a primary sealing space, wherein the position where the outer valve stem (5) and the valve body (1) move relative to each other is located in the primary sealing space and the position where the outer valve stem (5) and the inner valve stem (4) move relative to each other is located in the primary sealing space; Secondary sealing method: the movement chamber (12) inside the valve core frame (11) forms a second sealing space, and the valve plate (3) is connected to the card plate (14) through the connecting rod (10), the inner valve stem (4) and the valve plate (3) are connected to the card plate (14) through the connecting rod (10), the inner valve stem (4) and the card plate (14) are movably connected, and the movement of the inner valve stem (4) can push the card plate (14) closer to or away from the connecting rod (10); the second sealing space is used to wrap up the connection between the inner valve stem (4) and the card plate (14), and at the same time wrap up the connection between the card plate (14) and the connecting rod (10); Three-stage sealing method: when the outer valve stem (5) drives the valve core frame (11) to move toward the bottom of the valve body (1), it moves until the bellows group (6) is extended to the maximum length, and the inner valve stem (4) moves downward. The inner valve stem (4) moves downward to squeeze the card plate (14), causing the card plate (14) to rotate. The rotated card plate (14) squeezes the connecting rod (10), and the connecting rod (10) drives the valve plate (3) to seal the air inlet (2) or the air outlet (9); after the valve plate (3) blocks the air inlet (2) or the air outlet (9), there is a gap between the bottom of the valve plate (3) and the bottom of the valve body (1), and there is a gap between the bottom of the valve core frame (11) and the bottom inside the valve body (1).

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