Butterfly valve

Abstract

The invention provides a butterfly valve which comprises a valve body which is installed between the air inlet end and the air outlet end of a ventilation pipeline and comprises a main ventilation opening, and the side wall of the main ventilation opening is shrunk towards one end of the main ventilation opening in an inclined mode. The main valve plate is connected with a transmission main shaft through a first rotating arm which is eccentrically arranged, the main valve plate is arranged in the main air vent through the transmission main shaft, and the main valve plate is divided into a long part and a short part by the first rotating arm; the first driving part is connected with the transmission main shaft and is used for rotating in a preset first direction according to a valve opening instruction, so that the short part of the main valve plate is driven by the transmission main shaft and the first rotating arm to rotate towards the contracted end of the main air vent in an off-axis manner; and the long part of the main valve plate is driven to rotate towards the other end opposite to the main air vent in an off-axis manner, so that the main air vent is opened.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to a butterfly valve. Background Art

[0002] In semiconductor manufacturing processes, a throttle valve (TV) is usually required to control the flow rate and pressure of the inflowing gas at different levels.

[0003] In existing TV, the valve plate is usually coaxial with the valve body, and the main axis is located in the center of the valve body. The coaxial structure of the valve plate and the valve body easily causes friction between the side wall of the vent and the positive axis symmetrical rotating valve plate at the valve closing position, which has an adverse effect on the sealing performance and service life of the butterfly valve.

[0004] In order to overcome the above-mentioned defects of the prior art, there is an urgent need in the art for a butterfly valve for reducing the friction between the side wall of the vertical vent and the axially symmetrical rotating valve plate at the valve closing position, thereby improving the sealing performance and service life of the butterfly valve. Summary of the invention

[0005] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or decisive elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0006] In order to overcome the above-mentioned defects in the prior art, the present invention provides a butterfly valve for reducing the friction between the side wall of the vertical vent and the axially symmetrical rotating valve plate at the valve closing position, thereby improving the sealing performance and service life of the butterfly valve.

[0007] Specifically, the butterfly valve provided according to the first aspect of the present invention includes: a valve body, installed between the air inlet end and the air outlet end of the ventilation pipeline, and including a main air vent, wherein the side wall of the main air vent is inclined and contracted toward one end of the main air vent; a main valve plate, connected to a transmission main shaft via an eccentrically arranged first swing arm, and arranged in the main air vent via the transmission main shaft, wherein the main valve plate is divided into a long part and a short part by the first swing arm; and a first driving part, connected to the transmission main shaft, for rotating in a preset first direction according to a valve opening instruction, so as to drive the short part of the main valve plate to rotate off-axis toward one end that contracts the main air vent via the transmission main shaft and the first swing arm, and drive the long part of the main valve plate to rotate off-axis toward the other end opposite to the main air vent, so as to open the main air vent.

[0008] Furthermore, in some embodiments of the present invention, the first drive unit also rotates in an opposite second direction according to a valve closing instruction, so as to drive the long part of the main valve plate to rotate off-axis at one end that contracts toward the main air vent via the transmission main shaft and the first swing arm, and drive the short part of the valve plate to rotate toward the other end opposite to the main air vent to close the main air vent.

[0009] Furthermore, in some embodiments of the present invention, the direction of the contact point between the transmission main shaft and the farthest end of the long portion of the main valve plate and the main air vent is perpendicular to the inclined and contracted side wall of the main air vent, so that the farthest end of the long portion of the main valve plate just contacts the inclined and contracted side wall of the main air vent when the main valve plate rotates off-axis to its closed position.

[0010] Furthermore, in some embodiments of the present invention, the length ratio of the short part to the long part of the main valve plate is 0.5-0.7 to prevent the short part of the main valve plate from rubbing against the side wall of the main vent when the end contracting toward the main vent rotates off-axis.

[0011] Furthermore, in some embodiments of the present invention, the main valve plate is annular, and its central area includes a secondary air vent, the transmission main shaft is a hollow structure, and a transmission secondary shaft is provided inside it, and the butterfly valve also includes: a secondary valve plate, which is connected to the transmission secondary shaft via a second swing arm and is arranged in the secondary air vent via the transmission secondary shaft; and a second driving unit, which is connected to the transmission secondary shaft and is used to drive the secondary valve plate to rotate off-axis via the transmission secondary shaft and the second swing arm to open or close the secondary air vent.

[0012] Further, in some embodiments of the present invention, in response to a first valve opening instruction indicating a large flow rate, the first drive unit and the second drive unit operate synchronously, and drive the main valve plate and the secondary valve plate to rotate off-axis in the first direction synchronously via the transmission main shaft and the transmission secondary shaft to open the main air vent. In response to a second valve opening instruction indicating a small flow rate, the first drive unit drives the main valve plate to rotate off-axis in the second direction via the transmission main shaft to close the main air vent, and the second drive unit drives the secondary valve plate to rotate off-axis in the first direction via the transmission secondary shaft to open the secondary air vent. In response to the valve closing instruction, the first drive unit and the second drive unit operate synchronously, and drive the main valve plate and the secondary valve plate to rotate off-axis in the second direction synchronously via the transmission main shaft and the transmission secondary shaft to close the main air vent and the secondary air vent.

[0013] Furthermore, in some embodiments of the present invention, in response to a first adjustment instruction indicating a large flow rate regulation, the first drive unit and the second drive unit first operate synchronously to drive the main valve plate and the auxiliary valve plate to rotate off-axis synchronously to coarsely adjust the gas flow rate, and the second drive unit then operates alone to drive the auxiliary valve plate to rotate off-axis to fine-tune the gas flow rate. In response to a second adjustment instruction indicating a small flow rate regulation, the first drive unit locks the rotation angle of the main valve plate, and the second drive unit operates alone to drive the auxiliary valve plate to rotate off-axis to fine-tune the gas flow rate.

[0014] Furthermore, in some embodiments of the present invention, the side wall of the secondary air vent is inclined and contracted toward one end of the secondary air vent, the second swing arm is eccentrically connected to the secondary valve plate, and divides the secondary valve plate into a long part and a short part, and the direction of the contact point between the transmission secondary shaft and the farthest end of the long part of the secondary valve plate and the secondary air vent is perpendicular to the inclined and contracted side wall of the secondary vent, so that the farthest end of the long part of the secondary valve plate just contacts the inclined and contracted side wall of the secondary air vent when the secondary valve plate rotates off-axis to its closed position.

[0015] Furthermore, in some embodiments of the present invention, a sealing ring is provided at the contact position between the main valve plate and the side wall of the main air vent, and / or the contact position between the auxiliary valve plate and the inner wall of the auxiliary air vent is in the shape of an inclined and expanded slope toward the inclined and contracted end of the auxiliary air vent, so that when the auxiliary valve plate rotates off-axis to its closed position, it just fits into the inclined and contracted side wall of the auxiliary air vent.

[0016] Further, in some embodiments of the present invention, the butterfly valve is arranged between a vacuum environment and an atmospheric environment, the main air vent and the auxiliary air vent are both inclined and contracted toward one end of the vacuum environment, and / or the first drive unit is connected to the transmission main shaft via a first reduction mechanism and a first transmission gear box, the second drive unit is connected to the transmission secondary shaft via a second reduction mechanism and a second transmission gear box, the transmission secondary shaft is connected to the inner wall of the hollow structure of the transmission main shaft via multiple sets of bearings, and / or the diameter of the auxiliary valve plate is 1 / 3 to 1 / 2 of the diameter of the main valve plate, so as to perform gas flow control in a working range lower than the main valve plate through the auxiliary valve plate, and perform gas flow control in a working range higher than the auxiliary valve plate through the main valve plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0018] Figure 1A 3D structural schematic diagram of a butterfly valve provided according to some embodiments of the present invention is shown.

[0019] Figure 2 A schematic cross-sectional structure diagram of a butterfly valve provided according to some embodiments of the present invention is shown.

[0020] Figure 3 A schematic structural diagram of a transmission mechanism of a butterfly valve provided according to some embodiments of the present invention is shown.

[0021] Figure 4 A schematic diagram showing the angle of a main valve plate provided according to some embodiments of the present invention is shown.

[0022] Figure 5 A schematic diagram showing the angle of a main valve plate provided according to some embodiments of the present invention is shown.

[0023] Figure 6 A 3D structural schematic diagram of an open main valve plate provided according to some embodiments of the present invention is shown.

[0024] Figure 7 A schematic cross-sectional structure diagram of an open main valve plate provided according to some embodiments of the present invention is shown.

[0025] Figure 8 A 3D structural schematic diagram of an open auxiliary valve plate provided according to some embodiments of the present invention is shown.

[0026] Fig. 9 A schematic cross-sectional structure diagram of an open auxiliary valve plate provided according to some embodiments of the present invention is shown.

[0027] Reference numerals:

[0028] 10 Valve body

[0029] 20 Main valve plate

[0030] 21 First spiral arm

[0031] 22. First drive unit

[0032] 23. Transmission spindle

[0033] 30 Auxiliary valve plate

[0034] 31 Second spiral arm

[0035] 32 Second drive unit

[0036] 33 Transmission countershaft

[0037] 40 Sealing ring DETAILED DESCRIPTION

[0038] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0041] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0042] As mentioned above, in the semiconductor manufacturing process, a throttle valve (TV) is usually required to control the flow rate and pressure of the inflowing gas at different levels.

[0043] In the existing throttle valve, the valve plate is usually coaxial with the valve body, and the main shaft is arranged in the center of the valve body. The coaxial device structure of the valve plate and the valve body easily causes friction between the side wall of the vent and the positive axis symmetrical rotating valve plate at the valve closing position, which has an adverse effect on the sealing performance and service life of the butterfly valve.

[0044] In addition, the existing throttle valve usually has only a single valve plate, which can only control a single pressure curve. Therefore, when the control pressure is small and the intake flow is large, or the pressure is large and the intake flow is small, it is easier for the TV to operate in an extreme working range with an opening less than 10 degrees or greater than 50 degrees, affecting the control effect of the throttle valve.

[0045] In order to overcome the above-mentioned defects of the prior art, the present invention provides a butterfly valve for reducing the friction between the side wall of the vertical vent and the axially symmetrical rotating valve plate at the valve closing position, thereby improving the sealing and service life of the butterfly valve and preventing the butterfly valve from operating in an extreme working range.

[0046] Please refer to Figure 1 to Figure 5 , Figure 1 A 3D structural schematic diagram of a butterfly valve provided according to some embodiments of the present invention is shown. Figure 2 A schematic cross-sectional structure diagram of a butterfly valve provided according to some embodiments of the present invention is shown. Figure 3 A schematic structural diagram of a transmission mechanism of a butterfly valve provided according to some embodiments of the present invention is shown. Figure 4 A schematic diagram showing the angle of a main valve plate provided according to some embodiments of the present invention is shown. Figure 5 A schematic diagram showing the angle of a main valve plate provided according to some embodiments of the present invention is shown.

[0047] like Figure 1 to Figure 3 As shown, the butterfly valve includes a valve body 10 , a main valve plate 20 and a first driving part 22 .

[0048] The valve body 10 is installed between the air inlet and the air outlet of the ventilation pipeline and comprises a main air vent, wherein the side wall of the main air vent is inclined and contracted toward one end of the main air vent.

[0049] The main valve plate 20 is connected to a transmission main shaft via an eccentrically arranged first rotary arm 21 and is arranged in the main vent via the transmission main shaft. Here, the main valve plate 20 is divided into a long part and a short part by the first rotary arm 21.

[0050] The first drive unit 22 is connected to the transmission main shaft. Here, the first drive unit 22 can be connected via a speed reducer and a transmission gear box to improve control accuracy and stability. It is used to rotate in a preset first direction (for example, counterclockwise in the figure) according to a valve opening instruction, so as to drive the short part of the main valve plate 20 to rotate off-axis at one end that contracts toward the main air vent via the transmission main shaft and the first swing arm 21, and drive the long part of the main valve plate 20 to rotate off-axis at the other end opposite to the main air vent to open the main air vent. Correspondingly, the first drive unit 22 also rotates in the opposite second direction (for example, clockwise in the figure) according to a valve closing instruction, so as to drive the long part of the main valve plate 20 to rotate off-axis at one end that contracts toward the main air vent via the transmission main shaft and the first swing arm 21, and drive the short part of the valve plate to rotate at the other end opposite to the main air vent to close the main air vent.

[0051] like Figure 4 As shown, the direction of the contact point between the transmission main shaft and the farthest end of the long part of the main valve plate 20 and the main air vent can be perpendicular to the inclined and contracted side wall of the main air vent, so that the farthest end of the long part of the main valve plate 20 just contacts the inclined and contracted side wall of the main air vent when the main valve plate 20 rotates off-axis to its closed position.

[0052] Furthermore, the length ratio of the short portion to the long portion of the main valve plate 20 may be 0.5-0.7 to prevent the short portion of the main valve plate 20 from rubbing against the side wall of the main vent when the end thereof shrinking toward the main vent rotates off-axis.

[0053] Here, the verticality does not mean that the direction of the contact point between the farthest end of the long part of the main valve plate 20 and the main vent must maintain an angle of 90° with the inclined and contracted side wall of the main vent, but should be broadly understood as a roughly vertical angle range of 85° to 95° to improve the controllability of the device. By setting the main vent to be inclined and contracted toward one end, the main valve plate 20 is divided into a long part and a short part. When the valve is opened, the short part of the main valve plate 20 is driven to rotate off-axis toward the end contracted by the main vent, and the long part of the main valve plate 20 is driven to rotate off-axis toward the other end opposite to the main vent. The present invention can make the main valve plate in the closed position no longer perpendicular to the side wall of the main vent, thereby providing an open valve opening path for the long part of the main valve plate 20, and avoiding the friction between the main valve plate 20 and the contracted end of the main vent through the off-axis rotating short part, so as to avoid the generation of particles during its operation to contaminate the process chamber and improve the sealing and service life of the butterfly valve.

[0054] In some embodiments, the main valve plate 20 may be annular, and its central area includes a secondary vent, and the transmission main shaft is a hollow structure, and a transmission secondary shaft is provided inside it. A bearing support is provided between the transmission main shaft and the transmission secondary shaft. Here, the butterfly valve also includes a secondary valve plate 30 and a second drive unit 32. The secondary valve plate 30 is connected to the transmission secondary shaft via the second swing arm 31, and is arranged in the secondary vent via the transmission secondary shaft. The second drive unit 32 is connected to the transmission secondary shaft, and is used to drive the secondary valve plate 30 to rotate off-axis via the transmission secondary shaft and the second swing arm 31 to open or close the secondary vent, thereby connecting through the reducer and the transmission gear box to improve the control accuracy and stability.

[0055] like Figure 5 As shown, the side wall of the auxiliary vent is inclined and contracted toward one end of the auxiliary vent, and the second swing arm 31 is eccentrically connected to the auxiliary valve plate 30, and divides the auxiliary valve plate 30 into a long part and a short part. The direction of the contact point between the transmission secondary shaft and the farthest end of the long part of the auxiliary valve plate 30 and the auxiliary vent is perpendicular to the inclined and contracted side wall of the auxiliary vent, so that the farthest end of the long part of the auxiliary valve plate 30 just contacts the inclined and contracted side wall of the auxiliary vent when the auxiliary valve plate 30 rotates off-axis to its closed position.

[0056] Here, the verticality does not mean that the direction of the contact point between the farthest end of the long part of the transmission main shaft and the main air vent must maintain an angle of 90° with the inclined and contracted side wall of the main air vent, but should be broadly understood as a roughly vertical angle range of 85° to 95° to improve the controllability of the device. In this way, when the auxiliary valve plate 30 is rotated off-axis to its closed position, the farthest end of the long part of the auxiliary valve plate 30 is divided into a long part and a short part by setting the auxiliary air vent to be inclined and contracted toward one end thereof. When the valve is opened, the short part of the auxiliary valve plate 30 is driven to rotate off-axis toward the end at which the auxiliary air vent contracts, and the long part of the auxiliary valve plate 30 is driven to rotate off-axis toward the other end opposite to the auxiliary air vent. The present invention can make the auxiliary valve plate 30 in the closed position no longer perpendicular to the side wall of the auxiliary air vent, thereby providing an open valve opening path for the long part of the auxiliary valve plate 30, and avoiding friction between the auxiliary valve plate 30 and the contracted end of the auxiliary air vent by the off-axis rotating short part, so as to avoid the generation of particles that contaminate the process chamber during its operation.

[0057] In some embodiments, the butterfly valve is arranged between a vacuum environment and an atmospheric environment, and the main vent and the auxiliary vent are both inclined and contracted toward one end of the vacuum environment, thereby limiting the erroneous rotation of the long part of the valve plate toward the vacuum end through the mechanical structure, and preventing gas leakage caused by the failure of the rotary motor lock. The first drive unit 22 is connected to the transmission main shaft via the first reduction mechanism and the first transmission gear box, and the second drive unit 32 is connected to the transmission secondary shaft via the second reduction mechanism and the second transmission gear box, and the transmission secondary shaft is connected to the inner wall of the hollow structure of the transmission main shaft via multiple sets of bearings.

[0058] In some embodiments, the diameter of the auxiliary valve plate 30 is 1 / 3 to 1 / 2 of the diameter of the main valve plate 20, so that the gas flow rate control in the working range lower than the main valve plate 20 is performed through the auxiliary valve plate 30, and the gas flow rate control in the working range higher than the auxiliary valve plate 30 is performed through the main valve plate 20. Here, the working range is generally 2% to 60% opening, preferably 10% to 50% opening.

[0059] In some embodiments, a sealing ring is provided at the contact position between the main valve plate 20 and the side wall of the main air vent, and / or the contact position between the auxiliary valve plate 30 and the inner wall of the auxiliary air vent is in the shape of an inclined and expanded slope at the end that is inclined and contracted toward the auxiliary air vent, so that when the auxiliary valve plate 30 rotates off-axis to its closed position, it just fits the inclined and contracted side wall of the auxiliary air vent.

[0060] The working principle of the above-mentioned butterfly valve will be described below in combination with some embodiments of the butterfly valve control method. Those skilled in the art will understand that these embodiments of the butterfly valve control method are only some non-restrictive implementation methods provided by the present invention, which are intended to clearly demonstrate the main concept of the present invention and provide some specific solutions that are convenient for the public to implement, rather than to limit all functions or all working modes of the butterfly valve. Similarly, the device structure of the butterfly valve is also only some non-restrictive implementation methods provided by the present invention, and does not constitute a limitation on the execution subject or execution order of each step in these butterfly valve control methods.

[0061] In some embodiments, the main valve plate 20 and the sub-valve plate 30 of the butterfly valve can be opened separately to adjust the flow rate of the main vent.

[0062] Please refer to Figure 6-7 , Figure 6 A 3D structural schematic diagram of an open main valve plate provided according to some embodiments of the present invention is shown. Figure 7 A schematic cross-sectional structure diagram of an open main valve plate provided according to some embodiments of the present invention is shown.

[0063] like Figure 6-7 As shown, the butterfly valve can respond to a first valve opening instruction indicating a large flow rate (for example: 6000-50000 sccm, 1-15 Torr), and the first drive unit 22 and the second drive unit 32 operate synchronously, driving the main valve plate 20 and the sub-valve plate 30 to rotate synchronously in the first direction off-axis via the transmission main shaft and the transmission sub-shaft to open the main air port.

[0064] Please refer to Figure 8-Figure 9 , Figure 8 A 3D structural schematic diagram of an open auxiliary valve plate provided according to some embodiments of the present invention is shown. Fig. 9 A schematic cross-sectional structure diagram of an open auxiliary valve plate provided according to some embodiments of the present invention is shown.

[0065] like Figure 8-Figure 9 As shown, the butterfly valve can respond to a second valve opening instruction indicating a small flow rate (for example: 1000-20000 sccm, 1-15 Torr), the first drive unit 22 drives the main valve plate 20 to rotate off-axis in the second direction via the transmission main shaft to close the main air vent, and the second drive unit 32 drives the secondary valve plate 30 to rotate off-axis in the first direction via the transmission secondary shaft to open the secondary air vent.

[0066] Furthermore, the butterfly valve can respond to a valve closing instruction, and the first drive unit 22 and the second drive unit 32 can operate synchronously, driving the main valve plate 20 and the auxiliary valve plate 30 to rotate off-axis in the second direction synchronously via the transmission main shaft and the transmission auxiliary shaft to close the main air vent and the auxiliary air vent.

[0067] In addition, the main valve plate 20 and the auxiliary valve plate 30 of the butterfly valve can also be opened in coordination to adjust the flow rate of the main vent hole.

[0068] Specifically, the butterfly valve can respond to the first adjustment instruction indicating large flow adjustment. The first drive unit 22 and the second drive unit 32 first operate synchronously to drive the main valve plate 20 and the auxiliary valve plate 30 to rotate off-axis synchronously to coarsely adjust the gas flow. The second drive unit 32 then operates alone to drive the auxiliary valve plate 30 to rotate off-axis to fine-tune the gas flow.

[0069] Furthermore, the butterfly valve can respond to a second adjustment instruction indicating a small flow adjustment, the first drive unit 22 locks the rotation angle of the main valve plate 20, and the second drive unit 32 operates alone to drive the auxiliary valve plate 30 to rotate off-axis to fine-tune the gas flow.

[0070] In summary, the butterfly valve provided by the present invention can be used to reduce the friction between the side wall of the vertical vent and the axially symmetrical rotating valve plate at the closed valve position, thereby improving the sealing and service life of the butterfly valve and preventing the butterfly valve from operating in an extreme working range.

[0071] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0072] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A butterfly valve, characterized in that: include: The valve body is installed between the air inlet and the air outlet of the ventilation pipeline and includes a main air vent, wherein the side wall of the main air vent is inclined and contracted toward one end of the main air vent; a main valve plate connected to a transmission main shaft via an eccentrically arranged first swing arm and arranged in the main vent via the transmission main shaft, wherein the main valve plate is divided into a long portion and a short portion by the first swing arm; and The first driving unit is connected to the transmission main shaft and is used to rotate in a preset first direction according to a valve opening instruction, so as to drive the short part of the main valve plate to rotate off-axis toward the end contracted by the main air vent via the transmission main shaft and the first swing arm, and drive the long part of the main valve plate to rotate off-axis toward the other end opposite to the main air vent to open the main air vent.

2. The butterfly valve according to claim 1, characterized in that: The first driving part also rotates in an opposite second direction according to a valve closing instruction, so as to drive the long part of the main valve plate to rotate off-axis at one end contracted toward the main air vent via the transmission main shaft and the first swing arm, and drive the short part of the valve plate to rotate toward the other end opposite to the main air vent, so as to close the main air vent.

3. The butterfly valve according to claim 2, characterized in that: The direction of the contact point between the transmission main shaft and the farthest end of the long portion of the main valve plate and the main air vent is perpendicular to the inclined and contracted side wall of the main air vent, so that the farthest end of the long portion of the main valve plate just contacts the inclined and contracted side wall of the main air vent when the main valve plate rotates off-axis to its closed position.

4. The butterfly valve according to claim 1, characterized in that: The length ratio of the short part to the long part of the main valve plate is 0.5-0.7, so as to prevent the short part of the main valve plate from rubbing against the side wall of the main vent when the end thereof shrinking toward the main vent rotates off-axis.

5. The butterfly valve according to claim 1, characterized in that: The main valve plate is annular, and its central area includes a secondary vent. The transmission main shaft is a hollow structure, and a transmission secondary shaft is provided inside. The butterfly valve also includes: an auxiliary valve plate connected to the secondary transmission shaft via a second swing arm and disposed in the auxiliary vent via the secondary transmission shaft; and The second driving part is connected to the transmission secondary shaft and is used to drive the secondary valve plate to rotate off-axis via the transmission secondary shaft and the second swing arm to open or close the secondary air vent.

6. The butterfly valve according to claim 5, characterized in that: In response to a first valve opening instruction indicating a large flow rate, the first driving unit and the second driving unit operate synchronously, and drive the main valve plate and the auxiliary valve plate to rotate synchronously in the first direction off-axis via the transmission main shaft and the transmission auxiliary shaft to open the main vent. In response to a second valve opening instruction indicating a small flow rate, the first driving unit drives the main valve plate to rotate off-axis in the second direction via the transmission main shaft to close the main air vent, and the second driving unit drives the auxiliary valve plate to rotate off-axis in the first direction via the transmission secondary shaft to open the auxiliary air vent. In response to the valve closing instruction, the first drive unit and the second drive unit operate synchronously, driving the main valve plate and the auxiliary valve plate to rotate off-axis in the second direction synchronously via the transmission main shaft and the transmission auxiliary shaft to close the main air vent and the auxiliary air vent.

7. The butterfly valve according to claim 6, characterized in that: In response to the first adjustment instruction indicating large flow adjustment, the first drive unit and the second drive unit first operate synchronously to drive the main valve plate and the auxiliary valve plate to rotate off-axis synchronously to roughly adjust the gas flow, and then the second drive unit operates independently to drive the auxiliary valve plate to rotate off-axis to fine-tune the gas flow. In response to the second adjustment instruction indicating small flow adjustment, the first drive unit locks the rotation angle of the main valve plate, and the second drive unit operates alone to drive the auxiliary valve plate to rotate off-axis to fine-tune the gas flow.

8. The butterfly valve according to claim 6, characterized in that: The side wall of the secondary vent is inclined and contracted toward one end of the secondary vent, and the second rotary arm is eccentrically connected to the secondary valve plate and divides the secondary valve plate into a long part and a short part. The direction of the contact point between the transmission secondary shaft and the farthest end of the long portion of the auxiliary valve plate and the auxiliary air vent is perpendicular to the inclined and contracted side wall of the auxiliary air vent, so that the farthest end of the long portion of the auxiliary valve plate just contacts the inclined and contracted side wall of the auxiliary air vent when the auxiliary valve plate rotates off-axis to its closed position.

9. The butterfly valve according to claim 5, characterized in that: A sealing ring is provided at the contact position between the main valve plate and the side wall of the main vent, and / or The contact position between the auxiliary valve plate and the inner side wall of the auxiliary air vent is in the shape of an inclined slope that expands toward the inclined contracted end of the auxiliary air vent, so that when the auxiliary valve plate rotates off-axis to its closed position, it just fits the inclined contracted side wall of the auxiliary air vent.

10. The butterfly valve according to claim 5, characterized in that: The butterfly valve is arranged between a vacuum environment and an atmospheric environment, the main vent and the auxiliary vent are both inclined and contracted toward one end of the vacuum environment, and / or The first driving part is connected to the transmission main shaft via a first reduction mechanism and a first transmission gear box, the second driving part is connected to the transmission secondary shaft via a second reduction mechanism and a second transmission gear box, and the transmission secondary shaft is connected to the inner wall of the hollow structure of the transmission main shaft via multiple sets of bearings, and / or The diameter of the auxiliary valve plate is 1 / 3 to 1 / 2 of the diameter of the main valve plate, so that the gas flow rate control below the working range of the main valve plate can be performed through the auxiliary valve plate, and the gas flow rate control above the working range of the auxiliary valve plate can be performed through the main valve plate.

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