Butterfly valve for high vacuum system and control method

Abstract

The application belongs to the technical field of valves, and particularly relates to a butterfly valve for a high-vacuum system and a control method. The butterfly valve for the high-vacuum system comprises a valve body, a valve plate, a valve rod and a driving device. The inner side of the inlet of the flow-through hole of the valve body is a first conical annular surface, the inner side of the outlet is a second conical annular surface, the first conical annular surface is in the shape of a gradually increasing flared portion, the second conical annular surface is in the shape of a gradually narrowing flared portion, the middle part of the inner side of the flow-through hole of the valve body is an annular convex curved surface, and the first conical annular surface smoothly transitions to the second conical annular surface through the annular convex curved surface. The shape of the flow-through hole keeps the airflow stable during the opening process of the butterfly valve, keeps the airflow smooth when the valve plate is slightly opened, and keeps the airflow in the butterfly valve relatively linearly changed with the change of the opening degree of the valve plate. The control method of the butterfly valve for the high-vacuum system improves the intelligence degree of the butterfly valve during the working process, improves the self-regulating ability of the butterfly valve, and is beneficial to improving the stability of the fluid in the airflow system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of valves, and particularly relates to a butterfly valve for a high-vacuum system and a control method. BACKGROUND

[0002] The high-vacuum butterfly valve is used for opening or closing air flow in a vacuum pipeline, is suitable for high-vacuum pipelines of air and non-corrosive gas, and is a commonly used valve in the fields of biological engineering, food, pharmaceuticals, beverages, and chemical industry.

[0003] The butterfly valve includes a valve body and a valve plate, and the valve plate rotates around a valve shaft to achieve the purpose of opening and closing. The butterfly valve has two types of manual and electric according to the opening and closing mode. The manual high-vacuum butterfly valve has two types of handle operation and turbine operation, and the electric butterfly valve drives the valve plate of the high-vacuum butterfly valve to open and close through a motor. For example, the Chinese patent document with the publication number CN214146633U discloses a vacuum butterfly valve, which includes a valve body, the valve body includes a valve plate and a valve rod, the valve plate and the valve rod are connected, the valve rod can drive the valve plate to overturn, and the vacuum butterfly valve further includes a driving device, which can be a manual or electric device.

[0004] The current high-vacuum butterfly valve develops towards intelligence. For example, the Chinese patent document with the publication number CN216158314U discloses an intelligent butterfly valve based on the Internet of Things, which uses a controller, a valve closing device, and an auxiliary device. The controller can make the valve closing device work and close the butterfly valve, and the use is more intelligent. The Chinese patent document with the publication number CN214248322U discloses an internal visualization electric intelligent butterfly valve, which is provided with a control box connected with a line shell above. The internal visualization processing is performed, and the control box can be used to conveniently use the control keys to realize automation.

[0005] The current high-vacuum butterfly valve still has the following deficiencies: 1. The current butterfly valve has poor aerodynamic performance during opening, which is specifically shown in the following aspects: 1. the air flow stability is poor during opening, 2. the air flow is not smooth when the valve plate is opened by a small angle, and 3. the air flow in the butterfly valve cannot remain linearly changed with the change of the valve plate opening degree. 2. The intelligent control of the current butterfly valve is still in a low-end intelligent state. SUMMARY

[0006] The application aims to provide a butterfly valve for a high-vacuum system and a control method, and solve the technical problems of poor aerodynamic performance and low intelligent degree of the high-vacuum butterfly valve in the prior art.

[0007] To solve the above technical problems, the application adopts the following technical scheme:

[0008] The application provides a butterfly valve for a high vacuum system, which comprises a valve body, a valve plate, a valve rod and a driving device, the valve body is provided with a flow-through hole, the valve plate is matched with the flow-through hole, the valve rod is arranged in the valve body, the valve plate is arranged on the valve rod, the driving device is connected with the valve rod, the inlet inner side surface of the flow-through hole of the valve body is a first conical annular surface, the outlet inner side surface is a second conical annular surface, the first conical annular surface is in the shape of a gradually increasing flared portion, the second conical annular surface is in the shape of a gradually narrowing flared portion, the middle part of the inner side surface of the flow-through hole of the valve body is an annular convex arc surface, and the first conical annular surface is smoothly connected to the second conical annular surface through the annular convex arc surface.

[0009] Preferably, the valve plate is arranged on the inlet side of the flow-through hole of the valve body, and the valve plate is provided with a first conical outer peripheral surface matched with the first conical annular surface.

[0010] Preferably, the first conical outer peripheral surface is provided with a first annular groove, and the first annular groove is provided with a first sealing ring.

[0011] Preferably, the edge of the front side surface of the valve plate is sequentially connected to the first conical outer peripheral surface through a second conical outer peripheral surface, a third conical outer peripheral surface and a fourth conical outer peripheral surface, and the edge of the rear side surface of the valve plate is connected to the first conical outer peripheral surface through a fifth conical outer peripheral surface; the second conical outer peripheral surface, the third conical outer peripheral surface, the fourth conical outer peripheral surface and the first conical outer peripheral surface are in the shape of a gradually increasing flared portion from front to back, and the fifth conical outer peripheral surface is in the shape of a gradually narrowing flared portion from front to back; the second conical outer peripheral surface and the third conical outer peripheral surface, the third conical outer peripheral surface and the fourth conical outer peripheral surface, the fourth conical outer peripheral surface and the first conical outer peripheral surface, and the first conical outer peripheral surface and the fifth conical outer peripheral surface are all provided with an arc-shaped corner for smooth transition.

[0012] Preferably, the inclination of the first conical outer peripheral surface is 13-17°, the inclination of the second conical outer peripheral surface is 83-87°, the inclination of the third conical outer peripheral surface is 58-62°, the inclination of the fourth conical outer peripheral surface is 33-37°, and the inclination of the fifth conical outer peripheral surface is 53-57°.

[0013] Preferably, the inclination of the first conical annular surface is 13-17°, and the inclination of the second conical annular surface is 23-27°.

[0014] Preferably, the valve rod is provided with an assembly section penetrating through the valve body, the outer peripheral surface of the assembly section is provided with a plurality of second annular grooves, and the second annular grooves are provided with second sealing rings; the rear side of the assembly section is a connecting section, and a limiting convex flange is arranged between the assembly section and the connecting section.

[0015] Preferably, the driving device comprises an outer housing, a motor is arranged in the outer housing, an angular displacement encoder is arranged in the top cover of the outer housing, a transmission shaft is connected to the output shaft of the motor, and the angular displacement encoder is sleeved on the transmission shaft; the transmission shaft is connected to the valve rod; a control circuit board is arranged in the outer housing, and the motor and the angular displacement encoder are electrically connected to the control circuit board; a communication interface, a sensor interface, a power supply interface and a controller interface electrically connected to the control circuit board are arranged on the outer housing.

[0016] The application also provides a control method of the butterfly valve for a high vacuum system, the butterfly valve for a high vacuum system being the butterfly valve for a high vacuum system according to any one of the preceding aspects, the driving device of the butterfly valve for a high vacuum system comprising an outer housing, a motor arranged in the outer housing, an angular displacement encoder arranged in the top cover of the outer housing, a transmission shaft connected to the output shaft of the motor, and the angular displacement encoder being sleeved on the transmission shaft; the transmission shaft is connected to the valve rod; a control circuit board is arranged in the outer housing, and the motor and the angular displacement encoder are electrically connected to the control circuit board; a communication interface, a sensor interface, a power supply interface and a controller interface electrically connected to the control circuit board are arranged on the outer housing;

[0017] The control method is an ab learning method, wherein the parameter b reflects the flow characteristics of the process gas in the butterfly valve, and the parameter a reflects the proportional relationship between the flow characteristics and the size of the equipment chamber, and specifically comprises the following steps:

[0018] Automatic learning and self-adaptive stage: during the starting period of the system in which the butterfly valve for a high vacuum system is arranged, the valve plate of the butterfly valve is controlled to be at different opening degrees, the opening degree of the valve plate is detected by the angular displacement encoder, and the valve plate opening degree data is transmitted to the control circuit board; the pressure in the equipment chamber is detected by a pressure sensor, and the pressure data is transmitted to the control circuit board through the sensor interface, and the control circuit board records the valve plate opening degree, the pressure in the equipment chamber, the pressure change time and other data, and the values of a and b are obtained from the measured data, and then the size of the equipment chamber, the type of the process gas and the flow of the process gas are calculated;

[0019] The control circuit board is set with the instruction pressure of the equipment chamber, the optimal opening degree data of the valve plate is obtained based on the relationship between the opening degree of the valve plate and the pressure in the equipment chamber learned in the foregoing, the optimal opening degree data makes the equipment chamber be at the set specified pressure; then the control circuit board adjusts the valve plate to be at the optimal opening degree, and when the pressure in the equipment chamber is close to the instruction pressure, a convolution algorithm is applied to complete the fine adjustment of the opening degree change of the valve plate.

[0020] Preferably, the values of a and b are calculated according to the following formula, and the opening degree of the valve at the expected pressure is calculated and controlled:

[0021] p´=a×A×p+b

[0022] wherein,

[0023] 1) the values of the two parameters a and b are learned at the beginning and can also be learned during subsequent operation;

[0024] 2) A is the flow area of the valve, and A is calculated as follows:

[0025] Diam = max(0, 1.196x - 0.19); x is the valve rotation angle operating range 3-90°; Daim is the equivalent diameter of the valve bore, unit mm, in actual operation, the valve rotation is below 2.5° for the closed position, and above 67°, the flow area changes, the valve flow capacity remains unchanged;

[0026] A = pi / 4 x Diam^2 / 1e6, unit m^2;

[0027] 3) Learning process of a and b values:

[0028] 3.1) Let x = 0°; the valve full-closed detection chamber pressure rate p' is assigned to b according to the above formula, unit Pa / s;

[0029] 3.2) Let x = 20° (or the most likely stable angle according to experience, such as 18°), calculate A value at this time according to 2), and calculate a = -b / A / p after detecting the absolute value abs(p') <=1e-5, wherein p is the current chamber pressure measurement value, and multiple points can be measured; learning is completed;

[0030] 4) Calculate the valve opening under the expected pressure

[0031] Valve_Command = (-b / (a*P_expect) x 1e6 / pi x 4)^0.5 + 0.193) / 1.196 / 90 x pi / 2;

[0032] wherein P_expect is the chamber pressure command, and Valve_Command is the calculated basic valve angle.

[0033] 5) +pid fine tuning on the basis of Valve_Command angle

[0034] Valve_Command = Valve_Command + (pid*abs(P_expect-P_Feedback) <=1)

[0035] Wherein, pid is the output value after pid, P_Feedback is the chamber pressure measurement, when the absolute value of the difference between the expected pressure and the chamber pressure measurement is less than 1Pa, the pid adjustment is allowed.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] 1. The inlet inner side surface of the flow passage hole of the valve body of the butterfly valve for high vacuum system is a first conical annular surface, the outlet inner side surface is a second conical annular surface, the first conical annular surface is a flared shape gradually increasing, the second conical annular surface is a tapered shape gradually narrowing, the middle part of the inner side surface of the flow passage hole of the valve body is an annular convex arc surface, and the first conical annular surface smoothly transitions to the second conical annular surface through the annular convex arc surface. The shape of the flow passage hole makes the airflow stable during the opening process of the butterfly valve, and the airflow can be kept smooth when the valve plate is opened by a small angle, and the gas flow in the butterfly valve can be relatively kept linearly changed with the change of the opening degree of the valve plate.

[0038] 2. The control method of the butterfly valve for high vacuum system first senses the pressure change in the inner cavity of the butterfly valve, and then controls the opening degree of the valve plate according to the sensing result, thereby improving the intelligence degree in the working process of the butterfly valve, improving the self-regulating ability of the butterfly valve, and being beneficial to improving the stability of the fluid in the airflow system. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application together with the embodiments thereof, and explain the present application, but do not constitute a limitation of the present application. In the drawings:

[0040] Figure 1 It is a perspective structural schematic view of an embodiment of the butterfly valve for high vacuum system of the present application.

[0041] Figure 2 It is a bottom view of an embodiment of the butterfly valve for high vacuum system of the present application.

[0042] Figure 3 It is an A-A sectional view of Figure 2 .

[0043] Figure 4 It is a front view of the valve rod in an embodiment of the butterfly valve for high vacuum system of the present application.

[0044] Figure 5 It is an A part enlarged view of Figure 3 .

[0045] Figure 6 It is a sectional view of the valve body in an embodiment of the butterfly valve for high vacuum system of the present application.

[0046] Figure 7 It is a sectional view of the valve plate in an embodiment of the butterfly valve for high vacuum system of the present application.

[0047] Figure 8 Figure 2 is a sectional view of the valve plate of another embodiment of the butterfly valve for high vacuum system.

[0048] In the figure, each reference numeral represents: valve body 1, flow-through hole 11, bolt hole 12, shaft hole 13, through hole 14, first conical annular surface 15, second conical annular surface 16, valve plate 2, front side 21, rear side 22, second conical outer peripheral surface 23, third conical outer peripheral surface 24, first conical outer peripheral surface 25, first annular groove 26, first sealing ring 261, fourth conical outer peripheral surface 27, fifth conical outer peripheral surface 28, valve stem 3, valve plate mounting surface 31, positioning pin hole 311, screw hole 312, threaded pin 313, screw 314, second annular groove 32, second sealing ring 321, limiting outer flange 33, connecting section 34, assembly section 35, driving device 4, outer housing 41, communication interface 411, sensor interface 412, power supply interface 413, controller interface 414, motor 42, top cover 43, circular groove 431, protective cover 44, circular groove 441, angular displacement encoder 45, transmission shaft 46, control circuit board 47. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0050] In one embodiment, a butterfly valve for high vacuum system is provided, please refer to Figures 1 to 8 .

[0051] As shown in Figure 1 , Figure 2 and Figure 3 , the butterfly valve for high vacuum system comprises a valve body 1, a valve plate 2, a valve stem 3 and a driving device 4, wherein the valve body 1 is provided with a flow-through hole 11 in the middle, and a plurality of bolt holes 12 are provided on the valve body 1 in the circumferential direction, which are used to connect the valve body 11 to the flanges of pipes in the vacuum system, and the flow-through hole 11 is in communication with the pipes. The hole in the valve body 1 is provided with an eccentricity of 1-5 mm.

[0052] As shown in Figure 3 , the valve plate 2 matches the flow-through hole 11, so that the valve plate 2 can block the flow-through hole 11; the valve stem 3 is arranged in the valve body 1, the valve plate 2 is mounted on the valve stem 3, the driving device 4 is connected with the valve stem 3, and the driving device 4 can drive the valve stem 3 to rotate within a range of 90 degrees, so that when the valve stem 3 rotates, it drives the valve plate 2 to rotate in the valve body 1, thereby changing the opening degree of the flow-through hole 11.

[0053] As shown in Figure 4 , one side of the valve rod 3 is provided with a valve plate mounting surface 31, two screw holes 312 and two positioning pin holes 311 are arranged on the valve plate mounting surface 31, and corresponding screw holes and positioning pin holes are arranged on the inner side of the valve plate 2, combined Figure 3 , the valve plate 2 is positioned by the threaded pin 313 arranged in the positioning pin hole 311, and then the valve plate 2 is fixed by the two screws 314 arranged in the screw holes 312.

[0054] As shown in Figure 3 , an axle hole 13 is arranged at the top of the flow-through hole 11 in the valve body 1, a through hole 14 is arranged at the bottom of the flow-through hole 11 in the valve body 1, the top end of the valve rod 3 is installed in the axle hole 13 through a bearing, and the lower part of the valve rod 3 passes through the through hole 14, specifically, the lower part of the valve rod 3 is provided with an assembly section 35, which passes through the through hole 14 of the valve body 1, combined Figure 4 , three second annular grooves 32 are arranged on the outer circumferential surface of the assembly section 35, and a second sealing ring 321 is arranged in the second annular groove 32 to increase the sealing performance.

[0055] As shown in Figure 5 , the rear side of the assembly section 35 on the valve rod 3 is a connecting section 34, and a limiting outer flange 33 is arranged between the assembly section 35 and the connecting section 34, and the connecting section 34 is connected to the front end of the driving device 4.

[0056] The driving device 4 in the embodiment is an electric driving device, as shown in Figure 2 , the driving device 4 includes an outer housing 41, and a motor 42 is arranged in the outer housing 41, the motor 42 is a stepping motor or a servo motor, as shown in Figure 5 , the outer housing 41 is provided with a top cover 43, the top of the top cover 43 is provided with a protective cover 44, the four corners of the top cover 43 are connected to the outer housing 41 by screws, the top cover 43 is provided with a circular groove 431 corresponding to the protective cover 44, the protective cover 44 is conical, the lower edge of the protective cover 44 is arranged in the circular groove 431, and the protective cover 44 is also connected to the top cover 43 by screws.

[0057] As shown in Figure 5 , an angular displacement encoder 45 is arranged in the top cover 43 of the outer housing 41, the angular displacement encoder 45 is an absolute value encoder, which can measure the absolute value of the rotation angle of the valve rod 3, the output shaft of the motor 42 is connected with a transmission shaft 46, the transmission shaft 46 is a hollow shaft, the output shaft of the motor 42 is connected to the lower end of the transmission shaft 46 by a key, and the connecting section 34 at the bottom of the valve rod 3 is also connected to the upper end of the transmission shaft 46 by a key, so that the motor 42 can drive the valve rod 3.

[0058] As shown in Figure 5As shown, a circular groove 441 is provided on the top of the protective cover 44, and the limiting outer flange 33 between the assembly section 35 and the connecting section 34 is supported in the circular groove 441, so that the protective cover 44 supports the valve stem 3 in the axial direction.

[0059] like Figure 5 As shown, the angular displacement encoder 45 is mounted on the drive shaft 46, and the rotation of the drive shaft 46 can be accurately transmitted to the angular displacement encoder 45.

[0060] like Figure 3 As shown, a control circuit board 47 is provided in the outer casing 41. The motor 42 and the angular displacement encoder 45 are electrically connected to the control circuit board 47. The rotation angle measured by the angular displacement encoder 45 represents the opening degree of the valve plate 2. The control circuit board 47 can control the motor 42 to work, and the opening degree of the valve plate 2 measured by the angular displacement encoder 45 can be fed back to the control circuit board 47.

[0061] like Figure 2 As shown, the bottom surface of the outer casing 41 is provided with a communication interface 411, a sensor interface 412, a power interface 413, and a controller interface 414 electrically connected to the control circuit board 47. The control circuit board 47 transmits data to the outside world through the communication interface 411, for example, transmitting the opening information of the valve plate 2 to the host computer through the communication interface 411; the control circuit board 47 receives sensor measurement data through the sensor interface 412, for example, a sensor that can measure the pressure inside the valve body 1 can be set, and the measured pressure data is transmitted to the control circuit board 47 through the sensor interface 412; the power interface 413 supplies power to the control circuit board 47; the control circuit board 47 receives control signals from the host computer through the controller interface 414, for example, setting the opening size of the valve plate 2 through the control signals transmitted by the host computer.

[0062] like Figure 6 As shown, the inlet of the flow hole 11 of the valve body 1 ( Figure 6 (The direction of the middle arrow indicates the flow direction) The inner side is a first conical annular surface 15, and the inner side of the outlet is a second conical annular surface 16. The first conical annular surface 15 is a gradually increasing flared shape, and the second conical annular surface 16 is a gradually narrowing constricted shape. The middle part of the inner side of the flow hole 11 of the valve body 1 is an annular convex arc surface 17. The first conical annular surface 15 smoothly transitions to the second conical annular surface 16 through the annular convex arc surface 17. Designing the inner side of the flow hole 11 in this shape is beneficial for the smooth installation of the valve plate 2 and for improving the stability and smoothness of the gas flow field in the flow hole 11.

[0063] like Figure 8As shown, in one embodiment, the valve plate 2 is provided with a first conical outer peripheral surface 25 that matches the first conical annular surface 15. The first conical outer peripheral surface 25 of the valve plate 2 is not provided with an annular groove, that is, the contact surface between the valve plate 2 and the valve body 1 is not sealed by a sealing ring. This type of butterfly valve is a non-sealing butterfly valve. Non-sealing butterfly valves are allowed to have internal leakage and are mainly used as low-load butterfly valves in ventilation ducts and other fields.

[0064] And such Figure 7 As shown, in this embodiment, a first annular groove 26 is provided on the outer peripheral surface of the first cone, combined with... Figure 3 As shown, a first sealing ring 261 is provided in the first annular groove 26, such as Figure 3 As shown, in this embodiment, the valve plate 2 is disposed on the inlet side of the flow hole 11 of the valve body 1, and the contact surface between the valve plate 2 and the valve body 1 is sealed by the first sealing ring 261.

[0065] like Figure 7 As shown, the edge of the front side 21 of the valve plate 2 transitions sequentially to the first conical outer peripheral surface through the second conical outer peripheral surface 23, the third conical outer peripheral surface 24, and the fourth conical outer peripheral surface 27. Figure 7 The first conical outer peripheral surface is the plane where the groove of the first annular groove 26 is located. The edge of the rear side surface 22 of the valve plate 2 transitions to the first conical outer peripheral surface through the fifth conical outer peripheral surface 28. The second conical outer peripheral surface 23, the third conical outer peripheral surface 24, the fourth conical outer peripheral surface 27 and the first conical outer peripheral surface are flared openings that gradually increase from front to back, and the fifth conical outer peripheral surface 28 is a constricted opening that gradually narrows from front to back. Furthermore, there are smooth transition arc angles between the second conical outer peripheral surface 23 and the third conical outer peripheral surface 24, between the third conical outer peripheral surface 24 and the fourth conical outer peripheral surface 27, between the fourth conical outer peripheral surface 27 and the first conical outer peripheral surface, and between the first conical outer peripheral surface and the fifth conical outer peripheral surface 28.

[0066] like Figure 7 As shown, in this embodiment, the first conical outer peripheral surface ( Figure 7 The slope of the first conical outer peripheral surface (which is the plane where the groove of the first annular groove 26 is located) is 15°, the slope of the second conical outer peripheral surface 23 is 85°, the slope of the third conical outer peripheral surface 24 is 60°, the slope of the fourth conical outer peripheral surface 27 is 35°, and the slope of the fifth conical outer peripheral surface 28 is 55°. The slope of the first conical annular surface 15 inside the valve body 1 is 15°, which can have an error of 0.2°, and the slope of the second conical annular surface 16 is 25°.

[0067] The aforementioned special angle setting helps improve the aerodynamic performance of valve plate 2 at a small opening angle, ensuring the stability and smoothness of the gas flow.

[0068] In one embodiment, a control method of a butterfly valve for a high vacuum system is provided for controlling the butterfly valve for a high vacuum system in the above-mentioned embodiments. The control method is an ab learning method, in which parameter b reflects the flow characteristics of the process gas in the butterfly valve, and parameter a reflects the proportional relationship between the flow characteristics and the size of the equipment chamber. Specifically, the control method comprises the following steps:

[0069] (1) Automatic learning and self-adaptive phase: In the initial stage of the system in which the butterfly valve for a high vacuum system is located, the valve plate of the butterfly valve is controlled to be at different opening degrees, and the opening degree of the valve plate is detected by an angular displacement encoder. The valve plate opening degree data is transmitted to the control circuit board. The pressure in the equipment chamber is detected by a pressure sensor, and the pressure data is transmitted to the control circuit board through the sensor interface. The control circuit board records the valve plate opening degree, the pressure in the equipment chamber, the pressure change time, and other data. The values of ab are obtained from these measured data, and the size of the equipment chamber, the type of process gas, and the flow of process gas are calculated.

[0070] In this phase, under the drive of the driving device 4, the pressure in the equipment chamber is measured by the pressure sensor when the valve plate 2 is at a fixed opening degree, and the change of the pressure in this process is recorded to determine whether the pressure is stable. If not, the driving device 4 controls the valve plate 2 to change to another opening degree, and the pressure in the equipment chamber is continuously measured by the pressure sensor, and the change of the pressure in this process is recorded. In this way, the test is carried out until the valve plate 2 is at an opening degree and the pressure in the equipment chamber is in a stable state.

[0071] The types of process gas herein include, but are not limited to, N2, NH3, CH4, Ar, He, etc., or a mixed gas.

[0072] (2) The control circuit board is set with the instruction pressure of the equipment chamber. Based on the relationship between the opening degree of the valve plate and the pressure in the equipment chamber learned in the previous step, the control circuit board obtains the best opening degree data of the valve plate, which makes the equipment chamber at the set specified pressure. Then the control circuit board adjusts the valve plate to be at the best opening degree. When the pressure in the equipment chamber approaches the instruction pressure, a convolution algorithm is applied to complete the fine adjustment of the opening degree change of the valve plate. When fine adjustment is performed, the im2col function can be used.

[0073] The control method of the butterfly valve for a high vacuum system improves the intelligence level of the butterfly valve during operation, improves the self-adjusting ability of the butterfly valve, and is conducive to improving the stability of the fluid in the gas flow system.

[0074] The control method of the butterfly valve for a high vacuum system above is specifically used to calculate the values of a and b according to the following formula, and to calculate the valve opening degree under the expected pressure:

[0075] p´=a×A×p+b

[0076] wherein,

[0077] 1) the values of the two parameters a and b are learned at the beginning and can also be learned during subsequent operation;

[0078] p' is the measured rate of change of pressure;

[0079] 2) A is the flow area of the valve, and the value of A is calculated as follows:

[0080] Diam = max(0, 1.196x - 0.19); x is the valve rotation angle operating range 3-90°; Daim is the equivalent diameter of the valve bore, unit mm, in actual operation, the valve rotation is below 2.5° for the closed position, and above 67°, the flow area changes, and the valve flow capacity remains unchanged;

[0081] A = pi / 4 x Diam^2 / 1e6, unit m^2;

[0082] Here, pi is the value of π; 1e6 is 10 to the power of 6;

[0083] 3) Learning process of a and b values:

[0084] 3.1) Let x = 0°; detect the rate of change of chamber pressure p' when the valve is fully closed, and assign the rate of change of pressure p' to b according to the above formula, unit Pa / s;

[0085] 3.2) Let x = 20° (or the most likely stable angle according to experience, such as 18°), calculate the value of A at this time according to 2), and calculate a = -b / A / p when abs(p') <=1e-5, where p is the current chamber pressure measurement, and multiple points can be measured; learning is complete;

[0086] 4) Calculate the valve opening under the expected pressure

[0087] Valve_Command = (-b / (a*P_expect) x 1e6 / pi x 4)^0.5 + 0.193) / 1.196 / 90 x pi / 2;

[0088] where P_expect is the chamber pressure command, and Valve_Command is the calculated basic valve angle.

[0089] 5) +pid fine tuning on the basis of Valve_Command angle

[0090] Valve_Command = Valve_Command + (pid*abs(P_expect-P_Feedback) <=1)

[0091] wherein pid is the output value after pid, P_feedback is the chamber pressure measurement, and pid is allowed to adjust when the absolute value of the difference between the desired pressure and the chamber pressure measurement is less than 1 Pa.

[0092] The pid fine tuning here is to do differential adjustment under the control of the circuit board.

[0093] Special notes on the above calculation process:

[0094] (1) a, b are gas covering different molar mass, and have universality for different gas species;

[0095] (2) a, b contain the constant of the chamber volume;

[0096] (3) a is the valve-related coefficient, specifically, a covers the valve flow characteristic coefficient, and the valve flow characteristic coefficient given in the simulation is 0.03 (i.e. a = 0.03), and a is constant for different valve opening simulations, and the constant needs to be determined through experiments;

[0097] (4) When the process gas is stable, the pressure change in the chamber due to the evaporation of something will mainly affect the value of b. The value of b is the coefficient of the input process gas and the disturbance gas, and the mass flow of the disturbance gas cannot be known at present, and the learning is only the value of b under the stable mass flow of the process gas.

[0098] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A butterfly valve for a high vacuum system, comprising a valve body, a valve plate, a valve stem, and a drive device, wherein the valve body has a flow hole, the valve plate matches the flow hole, the valve stem is disposed in the valve body, the valve plate is mounted on the valve stem, and the drive device is connected to the valve stem, characterized in that: The inner side of the inlet of the flow-through hole of the valve body is a first conical annular surface, the inner side of the outlet is a second conical annular surface, the first conical annular surface is gradually enlarged flared, and the second conical annular surface is gradually narrowed. The valve plate is arranged at the inlet side of the flow-through hole of the valve body, and the valve plate is provided with a first conical outer peripheral surface matched with the first conical annular surface. The edge of the front side of the valve plate is sequentially transitioned to the first conical outer peripheral surface through a second conical outer peripheral surface, a third conical outer peripheral surface, and a fourth conical outer peripheral surface, and the edge of the rear side of the valve plate is transitioned to the first conical outer peripheral surface through a fifth conical outer peripheral surface; the second conical outer peripheral surface, the third conical outer peripheral surface, the fourth conical outer peripheral surface, and the first conical outer peripheral surface are gradually enlarged flared from front to back, and the fifth conical outer peripheral surface is gradually narrowed from front to back; and an arc-shaped corner for smooth transition is arranged between the second conical outer peripheral surface and the third conical outer peripheral surface, between the third conical outer peripheral surface and the fourth conical outer peripheral surface, between the fourth conical outer peripheral surface and the first conical outer peripheral surface, and between the first conical outer peripheral surface and the fifth conical outer peripheral surface. The inclination of the first conical outer peripheral surface is 13-17°, the inclination of the second conical outer peripheral surface is 83-87°, the inclination of the third conical outer peripheral surface is 58-62°, the inclination of the fourth conical outer peripheral surface is 33-37°, and the inclination of the fifth conical outer peripheral surface is 53-57°. The inclination of the first conical annular surface is 13-17°, and the inclination of the second conical annular surface is 23-27°.

2. The butterfly valve for high vacuum systems according to claim 1, characterized in that: A first annular groove is arranged on the first conical outer peripheral surface, and a first sealing ring is arranged in the first annular groove.

3. The butterfly valve for high vacuum systems according to claim 1, characterized in that: The valve rod is provided with an assembly section penetrating through the valve body, a plurality of second annular grooves are arranged on the outer peripheral surface of the assembly section, and a second sealing ring is arranged in each second annular groove; a connecting section is arranged on the valve rod at the rear side of the assembly section, and a limiting outer flange is arranged between the assembly section and the connecting section.

4. The butterfly valve for high vacuum systems according to claim 1, characterized in that: The driving device comprises an outer housing, a motor is arranged in the outer housing, an angular displacement encoder is arranged in the top cover of the outer housing, an output shaft of the motor is connected with a transmission shaft, and the angular displacement encoder is sleeved on the transmission shaft; the transmission shaft is connected to the valve rod; a control circuit board is arranged in the outer housing, and the motor and the angular displacement encoder are electrically connected to the control circuit board; a communication interface, a sensor interface, a power supply interface, and a controller interface electrically connected to the control circuit board are arranged on the outer housing.

Images