A magnetic fluid sealed high vacuum valve and method of use

Abstract

The application discloses a kind of magnetic fluid sealed high vacuum valves, including valve body assembly, the valve body assembly includes valve body, valve cover, valve rod and valve plate, magnetic fluid sealing device is integrated on the valve cover, the magnetic fluid sealing device includes transmission shaft and the magnetic fluid component being arranged on transmission shaft, the transmission shaft is connected with the valve rod screw thread transmission connection passing through valve cover, the valve rod is provided with the anti-rotation limit sliding structure for the rotation movement of transmission shaft is converted into the linear motion of valve rod.It also discloses the use method of the magnetic fluid sealed high vacuum valve.The magnetic fluid sealed high vacuum valve, magnetic fluid sealing device is integrated on the valve cover, realizes the rotation dynamic sealing of the stroke of transmission shaft not being limited, sets up anti-rotation limit sliding mechanism on the valve rod, can the rotation movement of transmission shaft be converted into the linear motion of valve rod, to realize the integrated design of valve, simple structure, small, small, good sealing performance.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically to a magnetohydrodynamic sealed vacuum valve used in ultra-high vacuum and high vacuum equipment, and its method of use. Background Technology

[0002] A vacuum is a gaseous state in a given space where the pressure is below one atmosphere. In this environment, sound cannot be transmitted because there is no medium. In vacuum technology, a vacuum is defined relative to the atmosphere. When a portion of the matter inside a specific space is expelled, causing its pressure to be lower than that of a standard atmosphere, we generally refer to this space as a vacuum or a vacuum state.

[0003] Vacuum valves play a crucial role in vacuum acquisition and application, changing airflow direction, regulating gas flow rate, and cutting off or connecting vacuum pipelines. They are an indispensable vacuum component, ensuring the normal operation of products under vacuum conditions.

[0004] Currently, vacuum valves used in the ultra-high vacuum and high vacuum fields in China typically employ O-rings for sliding or rotary sealing to ensure the required vacuum level. Alternatively, bellows can be used instead of O-rings for sliding sealing, allowing the O-rings to function only as static seals, while the bellows seal can generally meet the requirements of ultra-high vacuum and high vacuum operating environments.

[0005] However, sealing methods using U-shaped or welded metal bellows always suffer from problems such as short lifespan, short stroke, and difficulty in maintenance due to their materials and manufacturing processes.

[0006] Therefore, magnetohydrodynamic (MHD) sealing technology emerged. MHD sealing devices can be used in rotary sealing mechanisms, providing excellent sealing performance. They can also transform the dynamic seal of an O-ring into a static seal combining an O-ring and a MHD seal, significantly extending the seal's lifespan. However, MHD seals are generally used on rotating shafts; if applied to lifting devices, the issue of relative rotation needs to be addressed.

[0007] Products using magnetohydrodynamic sealing devices have complex structures and require a large space for installation. Summary of the Invention

[0008] The purpose of this invention is to solve the problems of existing vacuum valves, such as short stroke, difficult maintenance, and short lifespan when using bellows sealing, and complex, large, and inconvenient structure and use when using magnetic fluid sealing. The invention provides a magnetic fluid sealed high vacuum valve and its usage method that can achieve magnetic fluid sealing, unlimited stroke, convenient maintenance, small size, small footprint, simple structure and high vacuum sealing.

[0009] The technical solution adopted by the present invention to achieve its first inventive objective is: a magnetohydrodynamic (MHD) sealed high vacuum valve, comprising a valve body assembly, wherein the valve body assembly includes a valve body, a valve cover, a valve stem, and a valve plate, and a MHD sealing device is integrated on the valve cover, wherein the MHD sealing device includes a drive shaft and a MHD sealing assembly disposed on the drive shaft, the drive shaft passes through the valve cover and is threadedly connected to the valve stem, and the valve stem is provided with an anti-rotation limiting sliding mechanism for converting the rotational motion of the drive shaft into the linear motion of the valve stem. This magnetohydrodynamic (MHD) high-vacuum valve integrates the MHD sealing device onto the valve cover. The drive shaft passes through the valve cover and is directly threaded to the valve stem. The MHD sealing assembly is mounted on the drive shaft to achieve a rotational dynamic seal between the drive shaft and the valve cover. The drive shaft's stroke is unrestricted and can be operated as needed. To enable opening or sealing operations between the valve plate and the valve body, an anti-self-limiting sliding mechanism is installed on the valve stem, which converts the rotational motion of the drive shaft into the linear motion of the valve stem. This achieves an integrated design for the valve, resulting in a simple structure, small size, minimal footprint, and excellent sealing performance, meeting the design requirements for high vacuum.

[0010] Preferably, the magnetohydrodynamic (MHD) sealing assembly includes an annular permanent magnet, pole shoes, and a magnetohydrodynamic fluid. The inner wall of the pole shoes, which mates with the drive shaft, is provided with pole teeth. A magnetohydrodynamic filling area is formed between the pole teeth and the drive shaft, and the magnetohydrodynamic fluid fills this area to form a magnetohydrodynamic seal. The MHD sealing assembly preferably uses an annular permanent magnet, pole shoes, and a magnetohydrodynamic fluid. This MHD sealing assembly achieves a seal, meets the requirements for high-vacuum sealing, and has a simple structure, enabling integrated design.

[0011] Preferably, the drive shaft is provided with a magnetohydrodynamic (MHD) sealing device mounting ring. The mounting ring has an inner flow channel and a micro-hole connecting to the inner flow channel. The inner flow channel and the micro-hole are filled with magnetohydrodynamic fluid, forming a dynamic MHD sealing zone with the magnetohydrodynamic fluid filling area. To achieve higher vacuum requirements, another preferred solution is to have an inner flow channel and a micro-hole on the mounting ring of the drive shaft. The inner flow channel and the micro-hole are also filled with magnetohydrodynamic fluid, forming an integrated structure with the magnetohydrodynamic fluid in the filling area. This creates an effective magnetohydrodynamic sealing structure on the mounting ring, providing good sealing performance and suitable for sealing designs requiring high vacuum levels.

[0012] Preferably, the anti-rotation limiting sliding mechanism includes multiple anti-rotation limiting sliding grooves axially formed on the outer circumference of the valve stem and a limiting component integrated on the valve cover. The anti-rotation limiting sliding mechanism mainly prevents the valve stem from rotating by forming multiple anti-rotation sliding grooves on the outer circumference of the valve stem and integrating the limiting component on the valve cover. The limiting component cooperates with the anti-rotation sliding grooves to convert the rotational motion of the drive shaft into linear up-and-down sliding motion, thereby realizing the opening and closing operation of the valve plate.

[0013] Preferably, the limiting assembly includes a limiting sleeve and a limiting screw disposed on the limiting sleeve. The limiting sleeve is disposed inside the valve body and below the valve cover. The limiting screw is disposed radially on the limiting sleeve and passes through the inner wall of the limiting sleeve, slidably connecting with the anti-rotation limiting sliding groove on the valve stem. By providing a limiting sleeve inside the valve cover, the limiting screw can be fixed, and the drive shaft can be internally protected. The cooperation between the limiting screw and the anti-rotation limiting sliding groove effectively prevents the valve stem from rotating and allows for adjustment of the sliding fit.

[0014] Preferably, the end of the drive shaft connected to the valve stem is provided with a drive thread, and an internal thread is provided inside the valve stem corresponding to the drive thread; a connecting plate is provided on the drive shaft to seal with the valve cover, and a sealing groove is provided on the connecting plate, with a drive seal element provided inside the sealing groove. The drive shaft drives the valve stem to move up and down through the engagement of the drive thread and the internal thread. The connecting plate on the drive shaft, with its sealing groove and drive seal element, is provided to achieve a static seal between the drive shaft and the valve cover.

[0015] Preferably, the valve body has an internal sealing surface, and the valve plate has a sealing element that forms a static seal with the sealing surface. The internal sealing surface of the valve body, in conjunction with the sealing element on the valve plate, enables the closure and connection between the pipelines on both sides of the valve, allowing the valve body to form a vacuum chamber or be opened, thus meeting the design requirements for high vacuum.

[0016] Preferably, a magnetic sealing surface is provided on the plate surface where the valve plate mates with the sealing surface, and a strong magnetic adsorption component is provided on the outside of the valve body where the sealing surface is located. A magnetic seal is formed between the strong magnetic adsorption component and the magnetic sealing surface, and a double sealing structure is formed between the magnetic seal and the static seal of the sealing component.

[0017] Preferably, a valve body seal is provided at the connection between the valve cover and the valve body to achieve a static seal between them. The valve body seal includes a sealing base and a negative pressure groove integrally formed on the sealing base. To achieve a high vacuum valve design, a valve body seal is provided at the connection between the valve cover and the valve body. This valve body seal employs a negative pressure structure, consisting of a sealing base with a negative pressure groove. During use, the sealing base is positioned inside the sealing groove, and the negative pressure groove forms a negative pressure seal with the sealing point during the connection between the valve cover and the valve body, thus ensuring the sealing performance at the connection.

[0018] The technical solution adopted by this invention to achieve its second objective is: a method of using a magnetohydrodynamic sealed high vacuum valve, comprising the following steps: Step 1: Close the valve to form a vacuum cavity: Drive the transmission shaft clockwise manually or electrically. The transmission thread at the lower end of the transmission shaft rotates and moves relative to the valve stem. Due to the anti-rotation limiting structure formed between the limit screw and the anti-rotation limiting sliding groove on the valve stem, the valve stem is limited and slides downward along the axial direction. The valve stem drives the valve plate connected to it to move closer to the sealing surface inside the valve body. The sealing element on the valve plate cooperates with the sealing surface, or the static seal between the sealing element on the valve plate and the sealing surface and the magnetic seal formed by the magnetic sealing surface on the valve plate and the strong magnetic adsorption element form a double sealing structure between the valve plate and the sealing surface. The valve is closed, the pipes at both ends are isolated, and a vacuum cavity is formed inside the valve body. Step 2: Open the valve to connect the pipelines on both sides of the valve: Drive the transmission shaft counterclockwise by manual or electric means. The transmission shaft drives the valve stem to slide upward along the axis. The valve stem drives the valve plate connected to it to move away from the sealing surface. At this time, the sealing element and the sealing surface, and the magnetic sealing surface and the strong magnetic adsorption element are separated from the seal, the valve opens, and the pipelines at both ends are connected.

[0019] This method of use is simple to operate, the stroke of the moving shaft is unrestricted, a magnetohydrodynamic seal is formed between the drive shaft and the valve cover, the rotation and dynamic sealing performance of the drive shaft are good, and the valve stem drives the valve plate to move up and down, thereby forming a vacuum cavity inside the valve body to block the pipelines on both sides, or to open and connect the pipelines on both sides, which can meet the requirements for use under high vacuum conditions.

[0020] The beneficial effects of this invention are as follows: This magnetohydrodynamic sealing high vacuum valve integrates the magnetohydrodynamic sealing device on the valve cover, realizing a rotational dynamic seal between the drive shaft and the valve cover. The stroke of the drive shaft is unrestricted and can be transmitted as needed. An anti-self-limiting sliding mechanism is set on the valve stem, which can convert the rotational motion of the drive shaft into the linear motion of the valve stem. This achieves the overall integrated design of the valve, which has a simple structure, small size, small footprint, and good sealing performance, and can meet the design requirements of high vacuum. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the magnetohydrodynamic sealing high vacuum valve of the present invention; Figure 2 This is a schematic diagram of a structure of the magnetohydrodynamic sealing high vacuum valve of the present invention; Figure 3 yes Figure 1 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the structure of the magnetohydrodynamic sealing high vacuum valve of the present invention after the valve body is removed; Figure 5 This is a schematic diagram of one structure of the drive shaft in this invention; Figure 6 This is a schematic diagram of the transmission shaft from another angle in this invention; Figure 7 This is a schematic diagram of one structure of the valve stem in this invention; Figure 8 This is a schematic diagram of the open state structure of the magnetohydrodynamic sealing high vacuum valve of the present invention; Figure 9 This is a schematic diagram of a magnetic fluid sealing high vacuum valve in Embodiment 2 of the present invention; Figure 10 is a structural schematic diagram of a magnetohydrodynamic sealing high vacuum valve in Embodiment 3 of the present invention; In the diagram: 1. Valve body assembly; 2. Magnetohydrodynamic sealing device; 3. Valve body; 31. Sealing surface; 32. Valve body connecting flange; 4. Valve cover; 5. Valve stem; 51. Internal thread; 52. Anti-rotation limiting sliding groove; 6. Valve plate; 61. Dovetail sealing groove; 7. Seal; 8. Drive shaft; 81. Valve stem connecting end; 82. Drive end; 83. Drive thread; 84. Connecting plate; 85. Sealing groove; 86. Drive seal; 87. 9. Connecting part; 10. Annular permanent magnet; 11. Pole shoe; 12. Pole tooth; 13. Magnetorheological fluid filling area; 14. Magnetorheological fluid; 15. Limiting sleeve; 16. Limiting screw; 17. Mounting ring; 18. Micro-hole; 19. Inner flow channel; 20. Valve plate baffle; 21. Strong magnetic adsorption component; 22. Magnetic sealing surface; 23. Valve body static seal; 24. Sealing base; 25. Negative pressure groove; 26. Handwheel; 27. Locking nut. Detailed Implementation

[0022] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0023] Example 1: exist Figure 1 , Figure 2In the illustrated embodiment, a magnetohydrodynamic (MHD) sealed high-vacuum valve includes a valve body assembly 1. The valve body assembly 1 includes a valve body 3, a valve cover 4, a valve stem 5 disposed inside the valve body 3, and a valve plate 6. A MHD sealing device 2 is integrated on the valve cover 4. The MHD sealing device 2 includes a drive shaft 8 and a MHD sealing assembly disposed on the drive shaft 8. The drive shaft 8 passes through the valve cover 4 and is threadedly connected to the valve stem 5. The valve stem 5 is provided with an anti-rotation limiting sliding mechanism for converting the rotational motion of the drive shaft 8 into the linear motion of the valve stem 5.

[0024] The valve cover is sealed on the valve body, and the valve stem and valve plate are connected and disposed inside the valve body to realize the closing and opening of the valve.

[0025] The valve body 3 is primarily made of 304 stainless steel, with mirror-polished inner and outer surfaces achieving a surface roughness of ≤0.8μm to ensure low adhesion of particles and air molecules. The valve body 3 contains a sealing surface 31, which cooperates with the valve plate 6 to open or close the valve.

[0026] The valve body 3 is provided with a valve body connecting flange 32, which is used to connect with equipment or pipeline components. The valve body connecting flange 32 can be a CF flange, an ISO-F flange, or a flange with an added loose flange to become a bolted connection, adapting to various connection methods.

[0027] The valve cover 4 is installed on the valve body 3 to achieve valve body sealing and also for the installation of the magnetohydrodynamic sealing device. A valve body static seal 20 is provided between the valve cover 4 and the valve body 3 to create a vacuum inside the valve body, thus forming a sealed vacuum space inside the valve cavity. Figure 3 As shown, the valve body static seal 20 includes a sealing base 21 and a negative pressure groove 22 integrally disposed on the sealing base 21.

[0028] like Figure 4 As shown, the valve plate 6 is connected to the valve stem 5 via a valve plate baffle 17 and is secured with hexagonal socket screws. A dovetail sealing groove 61 is provided on the lower surface of the valve plate 6, and a sealing element 7, which is an O-ring, is installed inside the dovetail sealing groove 61. The valve plate 6 and the sealing surface 31 of the valve body 3 are sealed by a static seal using an O-ring, which serves to connect and close the vacuum pipes on both sides of the valve, ensuring the cleanliness and reliability of the sealed space.

[0029] The magnetic fluid sealing device 2 includes a drive shaft 8 and a magnetic fluid sealing assembly. The magnetic fluid sealing assembly includes an annular permanent magnet 9, a pole shoe 10, and magnetic fluid 11. The pole shoe 10 has pole teeth 101 facing inwards towards the drive shaft 8, forming a magnetic fluid filling area 102 between the pole teeth 101 and the drive shaft 8. The magnetic fluid 11 fills the magnetic fluid filling area 102 to form a magnetic fluid seal. A magnetic circuit is formed between the annular permanent magnet 9, the pole shoe 10, and the drive shaft 8. Under the action of the magnetic field generated by the magnet, the magnetic fluid 11 placed between the drive shaft 8 and the gap between the pole teeth at the top of the pole shoe 10 is concentrated, forming an "O" ring that blocks the gap and achieves a seal. To secure the magnetic fluid sealing assembly, a locking nut 24 can be installed on the outside of the magnetic fluid sealing assembly.

[0030] The drive shaft 8 passes through the valve cover 4 and is connected to the valve stem 5. The valve plate 6 is located at the lower end of the valve stem 5 and moves up and down by the valve stem 5, thereby realizing the opening and closing of the valve.

[0031] like Figure 7 As shown, an internal thread 51 for connecting to the drive shaft 8 is provided inside the valve stem 5, and multiple anti-rotation limiting sliding grooves 52 are provided axially on the outer circumference of the valve stem 5. The anti-rotation limiting sliding mechanism includes multiple anti-rotation limiting sliding grooves 51 provided axially on the outer circumference of the valve stem 5 and a limiting component integrated on the valve cover 4.

[0032] like Figure 6 As shown, the drive shaft 8 includes a valve stem connecting end 81 and a drive end 82. The valve stem connecting end 81 is provided with a drive thread 83 on its outside. The valve stem connecting end 81 passes through the valve cover 4 and extends into the valve body 3 to connect with the valve stem internal thread 51 to form a threaded engagement. When the drive shaft 8 rotates, the valve stem 5 will move upward or downward, thereby driving the valve plate 6 to move to achieve separation from or formation of a seal with the sealing surface inside the valve body 3.

[0033] like Figure 5 As shown, the drive shaft 8 is also provided with a connecting plate 84, the connecting plate 84 is provided with a sealing groove 85, and the sealing groove 85 is provided with a transmission seal 86.

[0034] A limiting component for limiting the valve stem is also provided on the valve cover 4. The limiting component includes a limiting sleeve 12 and a limiting screw 13 provided on the limiting sleeve 12. The limiting sleeve 12 is connected to the lower part of the valve cover 4 and is located inside the valve body 3. The limiting screw 13 is radially located at the lower end of the limiting sleeve 12. In this embodiment, there are two limiting screws. The two limiting screws are radially located from the lower end of the limiting sleeve and extend out of the inner wall of the limiting sleeve. They cooperate with the anti-rotation limiting sliding groove 52 on the valve stem 5 to form a sliding limiting structure, which is used to prevent the valve stem 5 from rotating when the drive shaft rotates. Since the valve stem 5 is threadedly connected to the drive shaft 8, when the drive shaft 8 rotates, the valve stem 5 will move upward or downward. The movement of the valve stem 5 drives the valve plate 6 to form a sealing or unsealing state between the sealing surface 31 inside the valve body 3, so that the valve can play the role of connecting or disconnecting the pipelines on both sides.

[0035] like Figure 8 As shown, a connecting part 87 is provided at the outer end of the drive shaft 8. The connecting part 87 can be connected to a manual handwheel 23 or an electric rotating device. The drive shaft is rotated by the handwheel 23 or the electric rotating device to realize the opening and closing of the valve.

[0036] This magnetohydrodynamic high-vacuum valve, when the valve needs to be closed, rotates the drive shaft clockwise. Since the lower end of the drive shaft is provided with a drive thread that is connected to the valve stem thread, the drive thread at the lower end of the drive shaft also rotates when the drive shaft rotates. At this time, due to the limiting structure formed between the limit screw and the anti-rotation limiting sliding groove on the valve stem, the valve stem is limited and cannot rotate, but can only slide downward along the axis. The valve stem drives the valve plate connected to it to approach the sealing surface inside the valve body until the valve is closed, cutting off the pipelines at both ends, and the valve plate and the sealing surface form a seal.

[0037] like Figure 8 As shown, when the valve needs to be in the open state, when the drive shaft is rotated counterclockwise, the drive thread at the lower end of the drive shaft also rotates. Due to the limiting structure formed between the limit screw and the anti-rotation limiting sliding groove on the valve stem, the valve stem is limited and cannot rotate. It can only slide upward along the axis. The valve stem drives the valve plate connected to it to move away from the sealing surface inside the valve body until the valve is fully opened, connecting the pipes at both ends, and the valve plate is separated from the sealing surface.

[0038] Example 2: exist Figure 9In the illustrated embodiment, a magnetohydrodynamic (MHD) sealed high-vacuum valve has a technical solution that is basically the same as that in Embodiment 1, except that: a magnetohydrodynamic sealing device mounting ring 14 is provided at one end of the drive shaft 8 extending outside the valve cover 4, and the magnetohydrodynamic sealing device is mounted on the mounting ring 14. Since a vacuum space is formed inside the valve body 3 after the valve plate 6 is closed during use, to achieve a good seal for the magnetohydrodynamic sealing device 2, several micro-holes 15 and an inner flow channel 16 connecting the micro-holes 15 are provided in the mounting ring 14. The inner flow channel 16 and the micro-holes 15 are filled with magnetohydrodynamic (MHD) fluid 11, forming a dynamic magnetohydrodynamic (MHD) sealing zone with the magnetohydrodynamic (MHD) filling area 102. In use, the magnetohydrodynamic (MHD) fluid 11 fills the magnetohydrodynamic (MHD) filling area 102 between the pole shoe 10 and the drive shaft 5. The magnetohydrodynamic (MHD) fluid 11 enters the inner flow channel 16 through the micro-holes 15, forming a dynamic magnetohydrodynamic (MHD) sealing zone between the inner flow channel 16, the micro-holes 15, and the magnetohydrodynamic (MHD) filling area 102. This forms an effective dynamic seal and rotary seal, ensuring the sealing performance of the valve body cavity under high vacuum conditions.

[0039] Example 3: exist Figure 10 In the illustrated embodiment, a magnetohydrodynamic (MHD) sealed high-vacuum valve has a technical solution that is basically the same as that of Embodiment 1, except that: to achieve the design requirement of high vacuum, a strong magnetic adsorption element 18 is provided on the outside of the valve body 3, corresponding to the valve plate 6. A magnetic sealing surface 19 is provided on the valve plate 6, and a magnetic sealing structure is formed between the magnetic sealing surface 19 and the strong magnetic adsorption element 18. This creates a double-sealing structure between the valve plate 6 and the valve body sealing surface 31, achieving a high-vacuum seal for the pipelines on both sides of the valve. The MHD sealing device and the magnetic sealing structure work together to achieve a high-vacuum seal for the valve.

[0040] The magnetohydrodynamic (MHD) sealed high-vacuum valve described in the above embodiments achieves the high-vacuum design requirements of the valve by incorporating a MHD sealing device, ensuring the cleanliness and reliability of the sealing space inside the valve body. The transmission stroke is unrestricted and can be designed and used as needed. The valve stem's rotation is limited by a limiting component, and the transmission shaft drives the valve stem's movement, achieving sealing or opening between the valve plate and the internal sealing surface of the valve body. This ensures effective sealing while improving the valve's lifespan. Furthermore, the valve body remains unchanged even when opened outwards, meeting standardized and universal design requirements. The use of the MHD sealing device achieves effective sliding and rotary sealing, ensuring the cleanliness of the sealing cavity and avoiding the wear of O-ring dynamic seals, the accumulation of dirt on the sealing ring surface affecting sealing performance, and problems such as low service life, short stroke, and difficult maintenance associated with bellows seals.

[0041] This magnetohydrodynamic (MHD) high-vacuum valve utilizes a MHD sealing device to achieve a rotary dynamic seal, avoiding the slippage and rotational sealing issues associated with O-ring seals, thus ensuring the cleanliness and reliability of the sealing environment. It avoids the problems of short stroke and low lifespan associated with metal bellows seals, enabling this type of ultra-high vacuum valve to achieve a lifespan of millions of cycles or even higher. To simplify the overall valve structure and address the issues of large size and footprint, the MHD sealing device is integrated into the valve cover. A threaded structure at the lower end of the drive shaft, in conjunction with the internal thread on the valve stem, converts the rotational motion of the drive shaft into the vertical motion of the valve stem. Furthermore, to prevent relative rotation between the drive shaft and the valve stem, an anti-rotation limiting sliding groove is added to the outside of the valve stem, enabling vertical movement of the valve stem and thus facilitating valve opening and closing. This makes operation more convenient and simpler, and broadens the range of applications.

[0042] The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of protection of this invention should not be considered as limited to the specific forms stated in the embodiments. The scope of protection of this invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A magnetohydrodynamic (MHD) sealed high vacuum valve, comprising a valve body assembly (1), wherein the valve body assembly (1) comprises a valve body (3), a valve cover (4), a valve stem (5), and a valve plate (6), characterized in that: A magnetic fluid sealing device (2) is integrated on the valve cover (4). The magnetic fluid sealing device (2) includes a drive shaft (8) and a magnetic fluid sealing assembly disposed on the drive shaft (8). The drive shaft (8) passes through the valve cover (4) and is threadedly connected to the valve stem (5). The valve stem (5) is provided with an anti-rotation limiting sliding mechanism for converting the rotational motion of the drive shaft (8) into the linear motion of the valve stem (5). The anti-rotation limiting sliding mechanism includes multiple anti-rotation limiting sliding grooves (52) provided on the outer circumference of the valve stem (5) along the axial direction and a limiting component integrated on the valve cover (4); The limiting assembly includes a limiting sleeve (12) and a limiting screw (13) disposed on the limiting sleeve (12). The limiting sleeve (12) is disposed inside the valve body (3) and below the valve cover (4). The limiting screw (13) is disposed on the limiting sleeve (12) radially and passes through the inner wall of the limiting sleeve (12) and is slidably connected to the anti-rotation limiting sliding groove (52) on the valve stem (5).

2. The magnetohydrodynamic sealed high vacuum valve according to claim 1, characterized in that: The magnetic fluid sealing assembly includes an annular permanent magnet (9), a pole shoe (10), and a magnetic fluid (11). The inner wall of the pole shoe (10) that mates with the drive shaft (8) is provided with pole teeth (101). A magnetic fluid filling area (102) is formed between the pole teeth (101) and the drive shaft (8). The magnetic fluid (11) fills the magnetic fluid filling area (102) to form a magnetic fluid seal.

3. The magnetohydrodynamic sealed high vacuum valve according to claim 2, characterized in that: The drive shaft (8) is provided with a magnetic fluid sealing device mounting ring (14), and the mounting ring (14) is provided with an inner flow channel (16) and a micro hole (15) connecting the inner flow channel. The inner flow channel (16) and the micro hole (15) are filled with magnetic fluid (11), forming a dynamic magnetic fluid sealing area with the magnetic fluid filling area (102).

4. The magnetohydrodynamic sealed high vacuum valve according to any one of claims 1 to 3, characterized in that: The drive shaft (8) is provided with a drive thread (83) at one end connected to the valve stem (5), and an internal thread (51) is provided inside the valve stem (5) corresponding to the drive thread (83); a connecting plate (84) is provided on the drive shaft (8) to seal with the valve cover (4), a sealing groove (85) is provided on the connecting plate (84), and a drive sealing element (86) is provided inside the sealing groove (85).

5. The magnetohydrodynamic sealed high vacuum valve according to any one of claims 1 to 3, characterized in that: The valve body (3) has a sealing surface (31) inside, and the valve plate (6) has a sealing element (7) that forms a static seal with the sealing surface (31).

6. The magnetohydrodynamic sealed high vacuum valve according to claim 5, characterized in that: A magnetic sealing surface (19) is provided on the plate surface that mates with the sealing surface (31) of the valve plate (6). A strong magnetic adsorption component (18) is provided on the outside of the valve body (3) where the sealing surface (31) is located. A magnetic seal is formed between the strong magnetic adsorption component (18) and the magnetic sealing surface (19). A double sealing structure is formed between the magnetic seal and the static seal of the sealing component.

7. The magnetohydrodynamic sealed high vacuum valve according to any one of claims 1 to 3, characterized in that: The valve cover (4) and valve body (3) are provided with a valve body static seal (20) for achieving static sealing between the valve cover and the valve body. The valve body static seal (20) includes a sealing base (21) and a negative pressure groove (22) integrally provided on the sealing base (21).

8. A method of using the magnetohydrodynamic sealed high vacuum valve according to any one of claims 1 to 7, characterized in that... Includes the following steps: Step 1: Close the valve to form a vacuum cavity: Drive the transmission shaft clockwise manually or electrically. The transmission thread at the lower end of the transmission shaft rotates and moves relative to the valve stem. Due to the anti-rotation limiting structure formed between the limit screw and the anti-rotation limiting sliding groove on the valve stem, the valve stem is limited and slides downward along the axial direction. The valve stem drives the valve plate connected to it to move closer to the sealing surface inside the valve body. The sealing element on the valve plate cooperates with the sealing surface, or the static seal between the sealing element on the valve plate and the sealing surface and the magnetic seal formed by the magnetic sealing surface on the valve plate and the strong magnetic adsorption element form a double sealing structure between the valve plate and the sealing surface. The valve is closed, the pipes at both ends are isolated, and a vacuum cavity is formed inside the valve body. Step 2: Open the valve to connect the pipelines on both sides of the valve: Drive the transmission shaft counterclockwise by manual or electric means. The transmission shaft drives the valve stem to slide upward along the axis. The valve stem drives the valve plate connected to it to move away from the sealing surface. At this time, the sealing element and the sealing surface, and the magnetic sealing surface and the strong magnetic adsorption element are separated from the seal, the valve opens, and the pipelines at both ends are connected.

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