vacuum valve

Abstract

To provide a vacuum valve which can be surely operated and has higher energy efficiency.SOLUTION: The vacuum valve includes: a valve housing defining a passage connecting a first opening and a second opening of the valve housing; a valve body and a complementary seat disposed in the passage, the valve body and the complementary seat comprising a sealing member. The valve body being movable in a linear axial direction along an open position and a closed position. The valve body comprises: a valve body and a complementary seat cooperating with the seat in a closed position to hermetically close the first opening; and an electromechanical actuation unit for actuation of the valve body, the actuation unit comprising: a mechanical conversion unit comprising an electric motor, an input drivingly connected with the electric motor and an output drivingly connected with the valve body, wherein the mechanical conversion unit comprises an electromechanical actuation unit for converting a rotational output of the electric motor into a linear movement of the output to move the valve body in an axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vacuum valve for a medium vacuum, high vacuum or ultra-high vacuum system. A further aspect of the present invention relates to a method of operating a vacuum valve.

Background Art

[0002] Medium vacuum, high vacuum, ultra-high vacuum systems are used in many technical fields, industries or scientific applications. In particular, such a vacuum in the range of 100 to 10 -9 Pa sets very high requirements for the design of components used in such systems. In particular, the valves of such systems need to meet high standards as they must reliably prevent gas leakage when in the closed state.

[0003] Conventional vacuum valves are based on pneumatic or solenoid actuators. Such valves are generally reliable, but a significant amount of energy is required to operate the valve or hold it in the open or closed position. However, energy efficiency is becoming an increasingly important issue in view of environmental and cost considerations.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, an object of the present invention is to provide a vacuum valve that can be reliably operated and is more energy-efficient.

Means for Solving the Problems

[0005] According to a first aspect of the present invention, there is provided a vacuum valve for a medium vacuum, high vacuum or ultra-high vacuum system, the vacuum valve comprising a valve housing defining a passage connecting a first opening and a second opening of the valve housing, A valve body and a complementary seat arranged in the passage, wherein at least one of the valve body and the complementary seat is provided with a sealing member, the valve body is movable in a linear axis direction along an open position and a closed position, and the valve body cooperates with the seat in the closed position to airtightly close the first opening, the valve body and the complementary seat An electromechanical actuation unit for operating the valve body, wherein the actuation unit comprises a motor, an input unit driven by the motor, and an output unit driven by the valve body, wherein the mechanical conversion unit converts the rotational output of the motor into linear motion of the output unit to move the valve body in the axial direction, and It is equipped with.

[0006] Such electromechanical actuation units can be made very compact and efficiently convert input electrical energy into the operating motion of the valve body. Since the energy consumption of the vacuum valve according to the present invention is relatively low, it is not necessarily required to supply power via the power grid for its operation. It may operate from a battery or capacitor power source, or it may be equipped with a solar panel.

[0007] The electric motor may be, for example, an in-runner or out-runner type brushed motor or a brushless motor (such as a stepping motor). The motor alternatives offer flexibility in identifying the best solution based on overall characteristics.

[0008] Furthermore, the electromechanical actuation unit allows the valve body to be in any intermediate position, not just the open or closed position. For example, proper control of the motor provided by an internal or external control unit can further influence the dynamics of the valve body's movement during opening and closing.

[0009] At least one of the valve body and the seat may be provided with multiple sealing members.

[0010] According to one embodiment of the present invention, the mechanical conversion unit comprises a feed screw that cooperates with a nut element. Such a conversion unit is inexpensive and can be easily resized (scaled) to meet actual requirements.

[0011] For example, the output section may include a nut element. In this case, the nut element moves axially by the rotation of a lead screw, which is directly or indirectly provided by an electric motor. However, it is also conceivable to provide an axially movable screw and hold the nut element in a fixed position in the axial direction.

[0012] According to one embodiment, at least one first elastic element, such as a spring, is provided, which is supported by the valve housing and acts on the valve body so that a force is applied to the valve body, propelling it to the closed position in the axial direction. This force is a biasing force that supports the closing motion of the valve body. This means that less torque is provided by the motor to generate the desired closing force during the closing motion of the valve body. As a result, the dimensions of the motor can be reduced and at least one of the energy required to operate the valve is reduced.

[0013] According to one embodiment, the valve body is movable axially relative to the output. In other words, the valve body is not fixedly attached to the output to allow for compensation of at least one of the thermal effects and minor inaccuracies of the operation of the electromechanical actuation unit, particularly the electric motor.

[0014] The electromechanical actuation mechanism may include at least one second elastic element, such as a spring, which is supported by the output and acts on the valve body such that a force is exerted on the valve body that propels it axially away from the output. This biasing force helps to provide the above compensation.

[0015] The output unit and the valve body may be coupled by a coupling unit that restricts the relative axial movement between the output unit and the valve body. The coupling unit may be provided to ensure that the valve body moves together with the output unit when the maximum allowable spatial separation of these components is reached, particularly when the vacuum valve is open.

[0016] In embodiments comprising both a first and a second elastic element, the first elastic element may have higher elasticity than the second elastic element in order to obtain the desired valve characteristics.

[0017] According to one embodiment, the output section is rotatably fixed and held in place by a guide device. The guide device may include projections cooperating with axially extending guide slots or grooves. Alternative guide concepts, such as guide rails and / or guides based on the outer (non-rotationally symmetric) shape of the output section, may also be employed.

[0018] According to one embodiment, the electric motor and the input unit are drivably coupled via at least one reduction drive unit. Such a reduction drive unit allows for optimization of thrust and actuator linear velocity. This may include, for example, gears, belts, and / or pulley wheels. However, a direct drive unit may be used in which the output member of the motor is directly coupled to the input unit of the mechanical conversion unit.

[0019] According to one embodiment, the electromechanical actuation unit comprises at least one locking device and / or locking function for locking the output or valve body to a desired axial position. The locking function may be provided by a mechanical conversion unit or, if present, by a reduction drive unit. For example, the mechanical conversion unit and / or reduction drive unit may have self-locking properties, for example, for a particular design of its mechanical components. However, multiple locking devices or functions may also be provided to obtain design alternatives for improving packaging, cycle life, and energy efficiency. Locking methods include mechanical, electrical, and electromechanical concepts. An electric motor may be used as a locking device and then function as an electric locking device. An electric clamp break is an example of an electromechanical locking device.

[0020] The concept of self-locking is associated with many specific advantages, including reduced average power consumption over time, reduced motor wear, and improvements to the valve's conversion unit and associated control unit (electronics). In particular, the motor can be put into standby mode or completely shut down if the electromechanical actuation unit is in a self-locking state. In this case, specific holding breaks or active control of the motor are also eliminated. A further advantage is that the valve remains in its current state during a power outage, for example, in the open, closed, or intermediate position of the valve body.

[0021] According to one embodiment, a position sensor is provided for detecting the position of at least one of the output unit and the valve body. Such a sensor enables closed-loop control so that the data provided by the sensor can be used to control the electric motor. The sensor may be an encoder, and an optical sensor, a Hall effect-based sensor, or any other suitable sensor.

[0022] By controlling the motor accordingly based on information regarding the position of at least one of the output unit and valve body, the dynamics of the electromechanical actuation unit can be determined and adapted as needed. Furthermore, by positioning the valve body at a desired intermediate position, it is easy to control the gas flow dynamics within the vacuum system, influencing, suppressing, or enhancing the pressure-time profile, pressure spikes, gas velocity, generation and movement of flow-induced debris, and pump inlet pressure.

[0023] Furthermore, open-loop control of the motor can also be provided. For example, the operating unit includes a stepping motor equipped with a step counter. The data provided by the counter is an indicator of the actual position or state of the output unit.

[0024] According to a second aspect of the present invention, a vacuum valve for a medium vacuum, high vacuum, or ultra-high vacuum system is provided, the vacuum valve for a medium vacuum system, high vacuum system, or ultra-high vacuum system, wherein the vacuum valve is A valve housing that defines a passage connecting the first opening and the second opening of the valve housing, A valve body and complementary seat disposed in the passage, wherein the valve body and the complementary seat include a sealing member, the valve body is linearly movable between an open position and a closed position, and here the valve body cooperates with the seat in the closed position to close the passage of the vacuum housing, the valve body and the complementary seat, An actuating unit for actuating the valve body, In a cross-section perpendicular to the first opening, a sealing member having at least any one of having a non-circular shape, being hollow, having a PTFE material or coating portion, and having a fluoroelastomer material or coating portion Comprising. At least any one of the hollow material holding this sealing member, the coated material, and the fluoroelastomer material may have a circular shape.

[0025] The use of such a sealing member (a "low-force seal") that performs at least one of compression with a relatively low force and providing appropriate sealing characteristics when a relatively low force is acting helps to reduce the energy required to operate the valve. The concept according to the second aspect of the present invention can be combined with the vacuum valve according to the first aspect of the present invention, and vice versa.

[0026] According to one embodiment, first and second sealing members are provided, where the first sealing member is fixed to the valve body and the second sealing member is fixed to the housing. The first and second sealing members may be arranged to contact each other when the valve is closed. In this embodiment, when the valve body moves to the closed position, both sealing members compress each other. The compression between the seals provides a more reliable seal with a predetermined compression force in most cases than the compression from the seal to the metal. Or, in other words, the force required to obtain proper sealing of the valve is relatively low.

[0027] The first and second sealing members may be fixed to the corresponding parts by vulcanization. The sealing member may be a PTFE and / or fluoroelastomer material, and may also be a coating portion on the valve body and / or the seat.

[0028] A vacuum valve according to at least one of the first and second embodiments of the present invention may include an operating unit equipped with an energy storage unit for supplying electrical energy to an electric motor. As the concept of the present invention leads to a valve with reduced energy consumption, a suitable energy storage unit (e.g., a battery pack) allows the electric motor to operate for a considerable period of time without the need to connect to a power grid. If there is no wired connection to the control unit provided for at least one of motor control and valve state monitoring (e.g., a wireless data connection may be envisioned), the valve operation may be entirely cordless.

[0029] According to a third aspect of the present invention, a method for operating a vacuum valve is provided, particularly in accordance with the above-described embodiment, wherein the vacuum valve is A valve housing that defines a passage connecting the first opening and the second opening of the valve housing, A valve body and a complementary seat arranged in the passage, wherein the valve body and complementary seat are provided with a sealing member, the valve body is movable in a linear axis direction along an open position and a closed position, and the valve body cooperates with the seat in the closed position to airtightly close the first opening, An electromechanical actuation unit for operating the valve body, wherein the actuation unit comprises a motor, an input unit driven by the motor, and an output unit driven by the valve body, wherein the mechanical conversion unit converts the rotational output of the motor into linear motion of the output unit to move the valve body in the axial direction, and In a method for operating the vacuum valve comprising, The electric motor is operated during the movement of the valve body to the closed position such that the speed of the valve body decreases at least on one side before and during contact between the valve body and the seat.

[0030] In particular, if the sealing member is provided on the valve body, the velocity decreases before the sealing member contacts the seat. If the sealing member is provided on the seat, the velocity of the valve body may decrease before it contacts the sealing member. If sealing members are provided on both the seat and the valve body, the velocity of the valve body may decrease before the sealing members collide with each other.

[0031] To put it simply, reducing the valve's velocity provides a "soft landing" of the valve onto its complementary seat. A slower approach of the valve reduces stress on the sealing element and minimizes wear induction. Furthermore, selecting an appropriate velocity profile minimizes vibration during valve closure. This also reduces the generation and transport of fine debris particles within the valve, which can cause serious problems when introduced into vacuum systems.

[0032] According to one embodiment of this method, the motor is operated such that the movement of the valve body from the open position to the closed position takes longer than the movement of the valve body from the closed position to the open position. In particular, the motor is operated such that the compression of the sealing member during the movement of the valve body to the closed position takes longer than the depressurization of the sealing member during the movement of the valve body out of the closed position.

[0033] When a valve is opened, the problems of vibration and stress occurring in the sealing member, seat, and valve body are not very significant. Therefore, it is possible to open the valve faster than closing it, thereby demonstrating the valve's dynamic characteristics. This is especially true for reducing pressure in the sealing member.

[0034] According to one embodiment of this method, the motor operates in the closed position of the valve body so that the force acting on the sealing member does not fall below a predetermined threshold. This measure ensures that the valve is reliably closed. The force acting on the sealing member may be determined based on data provided by at least one of force, strain, or temperature sensors. In particular, data provided by appropriately placed force or strain sensors can be used to directly determine the force acting on the sealing member. For example, indirect determination of the force is also possible by estimating the force based on the temperature of at least one of the valve housing, seat, actuating unit, and valve body. According to the embodiment, the force acting on the sealing member is determined based on the operating variables of the motor. Such indirect determination of the force may be based on measured motor current or voltage data. For example, since current is essentially proportional to the force acting on the sealing member, the current required for motor rotation at a particular angle (e.g., an angle less than 5°) can be used to estimate the force acting on the sealing member.

[0035] Other sensors that can be optionally provided to monitor the state of the vacuum valve may be sources of data for determining or estimating the forces described above. The threshold may be a fixed value or may be determined based on the operating variables of at least one of the valve and vacuum systems. [Brief explanation of the drawing]

[0036] [Figure 1] Figure 1 shows a cross-sectional view of a first embodiment of the vacuum valve. [Figure 2] Figure 2 shows a perspective view of a cross-section of the first embodiment. [Figure 3] Figure 3 shows a perspective view of the first embodiment. [Figure 4] Figure 4 schematically shows a second embodiment of the vacuum valve. [Figure 5] Figure 5 shows a schematic top view of the second embodiment. [Figure 6] Figure 6 schematically shows a third embodiment of the vacuum valve. [Figure 7] Figure 7 shows a schematic top view of the third embodiment. [Figure 8]Figure 8 shows a flowchart visualizing an approach to optimizing the design of a vacuum valve. [Figure 9] Figure 9 shows a first embodiment of a method for operating a vacuum valve. [Figure 10] Figure 10 shows a second embodiment of the method for operating a vacuum valve. [Figure 11] Figure 11 shows a first embodiment of the low-force sealing member. [Figure 12] Figure 12 shows a second embodiment of the low-force sealing member in uncompressed and compressed conditions. [Figure 13] Figure 13 shows one embodiment of the coupling unit. [Figure 14] Figure 14 shows a third embodiment of a low-force seal arrangement in an uncompressed state. [Figure 15] Figure 15 shows a perspective view of a fourth embodiment of the vacuum valve. [Figure 16] Figure 16 shows a magnified portion of Figure 15. [Figure 17] Figure 17 shows a cross-sectional view of the fourth embodiment. [Figure 18] Figure 18 shows a magnified portion of Figure 17. [Modes for carrying out the invention]

[0037] Figures 1, 2, and 3 show a vacuum valve 10 with a housing 12. The housing 12 includes a bottom member 14 that defines a first chamber 16 having a first opening 18 and a second opening 20. Both openings 18 and 20 are connected to flange sections 22a and 22b, which allow the vacuum valve 10 to be integrated into medium, high, or ultra-high vacuum systems. The upper side of the chamber 16 is covered by a wall element 24, which abuts against a wall portion 26 of a guide device 28. The wall portion 26, together with a cover element 30, forms a second chamber 32. In other words, the multi-part housing 12 defines two chambers 16 and 32. These house the valve body (poppet 50) for sealing the opening 18 and the main components necessary for its operation, respectively, as will be described below. The chamber 16 essentially functions as a passage between the openings 18 and 20.

[0038] The second chamber 32 houses an electric motor 34, which is driven via a reduction drive unit 36 ​​having a lead screw 38. The reduction drive unit 36 ​​may include, for example, spur gears, worm gears, and / or planetary gears. The lead screw 38 cooperates with the nut 40, so that when the electric motor 34 is operated and rotates the lead screw 38, the projection 42 of the nut 40 engages with the axial slot 44 of the guide device 28, preventing the nut 40 from rotating, so that the nut 40 moves axially (axially AM).

[0039] The nut 40 is fixedly connected to the sleeve portion 46. The sleeve portion 46 is supported by the inner shoulder portion of the sleeve portion 46 and includes a first spring element 47 that acts on the tip element 48 which next contacts the poppet 50 equipped with a seal 52. The seal 52 may be, for example, a conventional O-ring or a low-force seal as described above and further described later.

[0040] The second spring element 54 is supported by an axial projection 56 of a guide device 28 that protrudes into the first chamber 16 through an opening in the wall element 24. The second spring element 54 acts on the poppet 50, pushing it downward toward the opening 18. The second spring element 54 radially surrounds the lower part of the sleeve 46 and is surrounded on the other hand by a bellows 58 that separates the second spring element from the interior of the first chamber 16.

[0041] When valve 10 is closed, the electric motor 34 starts and drives the lead screw 38. The rotation of the lead screw 38 causes the nut 40 to move axially downward, thereby pushing the sleeve 46 downward. This movement is transmitted via the first spring element 47 and the tip element 48 on the poppet 50, which are not fixedly connected to the sleeve 46. This movement is supported by a pre-compressed second spring element 54. Thus, the force provided by the spring element 54 acts in parallel with the thrust applied to the poppet 50 by the lead screw mechanism 38, 40, which converts the rotation of the lead screw 38 into axial translation of parts 40, 46, 47, 48, and 50. Thus, the second spring element 54 reduces the torque required to create the axial translation, and the energy consumption of the electric motor 34 is reduced. A further advantage is that the electric motor 34 can be made relatively small, especially if the reduction drive unit 36 ​​is appropriately selected.

[0042] When the seal 52 contacts the seat 60 surrounding the opening 18, compression begins, initiating the process of sealing the opening 18. At a given point, the compression of the seal 52 stagnates, and the poppet 50 stops moving axially. The poppet 50 is now in the closed position. Since there is a gap between the poppet 50 and the sleeve portion 46, there is no problem even if the electric motor 34 is operated for a short time. This will only cause a reduction in the gap and further compression of the first spring element 47.

[0043] If open-loop control of the electric motor 34 (e.g., a stepping motor) is provided, small inaccuracies in motor control can be compensated for by the gap. Of course, position sensors may be provided to monitor the position of any of the components 40, 46, 47, and 50 so that closed-loop control of the electric motor 34 can be provided.

[0044] If the feed screw mechanisms 38, 40 and / or the reduction drive unit 36 ​​have a self-locking design, no energy is required to hold the poppet 50 in the closed position. The spring elements 47, 54 push the poppet 50 against the seat 60. In this situation, the above gap also compensates for the difference in thermal expansion and / or stress relief of the components of the valve 10.

[0045] To open the valve 10, the lead screw 38 is rotated in the opposite direction by appropriate control of the electric motor 34, thereby inducing the sleeve portion 46, fixed to the nut 40, to move upward. Initially, the poppet 50 is still being pushed downward by the spring elements 47, 54. However, as the sleeve portion 46 retracts, the gap between the sleeve portion 46 and the poppet 50 widens, and the force provided by the first spring element 47 acting on the poppet 50 decreases. The coupling mechanism detailed below couples the poppet 50 to the sleeve portion 46 when the maximum gap is achieved. The poppet 50 then moves upward together with the sleeve portion 46 against the force applied by the spring element 54. It can move until it reaches the end position that defines the "fully open" state. However, any desired intermediate position between the closed position and the fully open position can be assumed by the poppet 50.

[0046] Figure 4 schematically shows a second embodiment of the vacuum valve 10. The electric motor 34 is positioned coaxially with a reduction drive unit 36, which is sequentially coupled via a belt 62 and pulleys 64 and 66 by a lead screw 38. The lead screw 38 cooperates with a nut 40 fixedly connected to a rod 68 that conveys a poppet 50 with a seal 52. Axial guidance is provided in this embodiment by a guide element 70 protruding through a guide opening 72 of the nut 40. For example, the guide element 70 functions as a guide rail. Details regarding the chamber 16 have been omitted for clarity.

[0047] In this configuration, the poppet stroke S is parallel to the axial movement AM of the nut 40 during the operation of the valve 10. However, both stroke S and axial movement AM are axial movements.

[0048] Figure 5 is a top view showing that the rotation axis RA1 of the pulley 64 (and motor 34), the rotation axis RA2 of the pulley 66 and lead screw 38, and the axial projection of the rod 68 are essentially arranged on the diagonal D of the cover 30. This arrangement is simple and compact.

[0049] An alternative compact arrangement is shown in Figures 6 and 7. The lead screw 38 is held by a bearing support 74, which includes a bearing 76. This is driven by an electric motor 34 connected to a reduction drive unit 36, which drives an output gear 78 that meshes with an input gear 80 fixed to the lead screw 38. The lead screw 38 cooperates with a nut 40 that is axially movable but rotationally fixed. The nut 40 is connected to the poppet 50 by a rod 68. In this embodiment, the stroke S, the input gear 80, and the axial movement AM and rotation axis RA2 of the lead screw 38 are arranged coaxially.

[0050] Figure 8 shows a flowchart to visualize an exemplary approach to optimizing the design of a vacuum valve according to the present invention and adapting it to market requirements. Key objectives, in addition to energy efficiency, include optimized flow conductance, optimized operating motion and dynamics, compact size, low impact speed during valve closure, temperature stability, reliable self-locking characteristics, and repeatable duty cycle. Non-performance related issues such as packaging, cost, and manufacturability may also be considered during valve optimization.

[0051] The leftmost flow requires the desired flow conductance through the valve as input A1. Appropriate variables, such as the diameter and stroke of the poppet or seal, are selected (A2), leading to the actual flow conductance (A3). These variables are editable to change A3.

[0052] The next flow on the right requires input of the desired sealing material (B1). Then, variables relating to further properties of the seal, such as its diameter, cross-section, and elasticity, are selected in step B2, and variables describing how it is retained (e.g., the shape of the groove in which the seal is placed, which affects the response due to relative thermal expansion) are selected. This information leads to further insights into at least one of the expected actual compressive force and the actual compressive force exerted by the seal (B3). Depending on this information, the above variables may be edited. This allows for optimization of the properties of the first spring element 47 (B4).

[0053] The next flow on the right requires, as input, a desired operating profile for the linear motion and thrust of the poppet 50, a desired torque and rotational speed, and a desired self-locking force (C1). Relevant variables are, for example, the diameter of the lead screw and / or the characteristic friction between the lead screw and the nut (C2). This leads, among other things, to the actual linear motion and the thrust response of the driving torque and rotational speed of the relevant parts. Further insights into the actual compressive force and the actual self-locking force are obtained (C3). This allows for the optimization of the characteristics of the second spring element 54 (C4).

[0054] The rightmost flow contains constraints (D1) on the desired motor type, such as brushed motor (D2), stepper motor (D3), inrunner (D4), or outrunner (D5). Relevant variables include, for example, motor torque, the provided rotational speed, and variables related to the duty cycle or its definition (D6). This leads to the actual required or expected value of the "power-in" (D7). The appropriate motor selection can be optimized based on these relevant variables.

[0055] In D8, it is necessary to determine whether a reduction drive or equivalent is required or desirable. The variables relevant here are the actual torque and rotational speed provided to the valve operation, and the reduction ratio (D9) that leads to the expected actual self-locking force (D10).

[0056] It should be emphasized that the optimization flow described above is illustrative only. Additional and / or modified optimization approaches may be employed. The order in which the optimization flow is executed may be freely chosen.

[0057] Figure 9 shows an exemplary duty cycle of a pre-fed vacuum valve according to the present invention in a position (P) vs. time (t) diagram. At time t=0, the valve poppet 50 is in the fully open position (position P1). When the electric motor 34 is activated, the poppet 50 is accelerated and moves relatively quickly toward the seat 60. The speed of the poppet 50 decreases aggressively even before the seal 52 begins to compress. This reflects the fact that the slope of the dashed moving curve becomes smaller before the contact seal 52 of the seat 60 (seal contact SC, position P2). During the compression of the seal 52, the speed of the poppet 50 decreases further until it reaches zero at the closed position (position P3, time t1). The seal 52 is compressed by the amount indicated by SR (compression range). The valve is appropriately controlled so that metal-to-metal contact (MMC) between the poppet 50 and the seat 60 is avoided. The approach outlined above results in a "soft landing" of the poppet 50 while the valve is closed.

[0058] If one or more components of the electromechanical actuation unit, such as the lead screw mechanisms 38, 40 and the reduction drive unit 36, have self-locking properties, then holding the poppet 50 in the closed position does not require the supply of electrical energy to the electric motor 34.

[0059] The opening of the vacuum valve begins at time t2 (P4). As already noted, the problem of generating vibration and / or stress in at least one of the seal member 52, seat 60, and valve body 50 is not significantly more pronounced when opening the valve than when closing it. Therefore, the poppet 50 can be accelerated rapidly. As a result, the depressurization of the seal 52 occurs much faster than its compression.

[0060] In the embodiment shown, the poppet 50 has already reached its maximum speed when the seal 52 is no longer in contact with the seat 60 (position P5). It moves further away from the seat 60 until it reaches the fully open position again (P3 at t6).

[0061] From the above description, it can be concluded that the duty cycle of the valve according to the present invention may be asymmetric with respect to opening and closing. In the above example, closing the valve (from 0 to t1) takes longer than opening the valve (from t2 to t3). This concept can be easily implemented by an electromechanical actuation unit for the vacuum valve according to the present invention, which allows for very precise control of the position and dynamics of the valve body and poppet. It is also possible to design at least one of the appropriate position-time profile and thrust profile for each application.

[0062] Figure 10 shows the effect occurring when the valve is closed in a force (F) versus time (t) graph. The horizontal dashed line indicates the minimum thrust force (Fmin) that should be applied to the seal 52 to ensure a proper seal. This value is lower than the compressive force F1 obtained after the valve is properly closed or closed. Differences in thermal expansion of the valve components can lead to a reduction in thrust or compressive force (see ΔT). If this effect is detected, the motor 34 can be activated, for example, by monitoring the position of the poppet 50 or other components of the actuating unit using appropriate sensors, to compensate for the effect with an appropriate response (see actuator response AR) and maintain the force within the desired seal compressive range SR1. Stress relaxation of the mechanical components involved can be another source of reduction in the force applied to the seal 52 (see StR).

[0063] Reducing the energy consumption of vacuum valves can also be achieved, regardless of the nature of the operating unit, by using so-called "low-force seals," that is, seals that can be properly compressed by applying a relatively small force, and / or seals that already have low-force sealing properties.

[0064] At least one of a seal comprising PTFE material or a coated portion, and a seal comprising fluoroelastomer material or a coated portion, are examples of such low-force seals. The desired properties can also be obtained by selecting a non-circular shape away from the circular cross-section of the seal. For example, a rhomboid seal 52 (located in groove 82 and not compressed), as depicted on the left side of Figure 12, deforms to a greater extent than a conventional O-ring of comparable dimensions when a given force is applied (Figure 12, right side). This effect is enhanced when the seal 52 is at least partially hollow (see Figure 11). A suitable hollow seal or a seal with a softer core may also have a shape different from the rhomboid geometric shape shown in Figure 11.

[0065] An exemplary embodiment of the mechanism connecting the poppet 52 and the sleeve portion 46 is shown in Figure 13. When the valve is open, the poppet 50 is pushed away from the sleeve portion 46 by a spring-biased tip element 48, resulting in a gap 84 between the parts. In this state, the projections of the fingers 86 of the sleeve portion 46 engage with the upper end of the groove 88 of the poppet 50 that holds it in this position. When the valve is closed, the poppet 50 is moved toward the sleeve portion 46 to compensate for, for example, slight inaccuracies in motor control and / or effects resulting from progressive seal compression and / or thermal effects (as shown in Figure 13).

[0066] While the valve is open, the sleeve portion 46 moves upward, but the poppet 50 remains pressed against the seat 60 by the spring elements 47, 54. The poppet 50 is actively lifted from the seat 60 only when the projection of the finger 86 engages with the upper end of the groove 86.

[0067] It should be easy to imagine the existence of numerous alternative mechanisms that can provide equivalent or equivalent types of coupling.

[0068] Figure 14 shows a further embodiment of a low-force seal, comprising seals 52a and 52b positioned on a poppet 50 and a seat 60, respectively, in an uncompressed state. While the valve is closed, seals 52a and 52b are in contact with each other and are gradually compressed. As already mentioned above, a lower force may be required to obtain a proper seal of such a valve than is required in conventional arrangements.

[0069] Figures 15 to 18 show a small vacuum valve 10 having an axially movable feed screw 38a that cooperates with an axially fixed nut 40a. The nut 40a is rotationally driven by an electric motor 34a positioned between the axial walls 90a and 90b.

[0070] The starting of the electric motor 34a causes the nut 40a to rotate. This then results in axial movement of the lead screw 38a, which is fixed to the shaft wall 90a and whose rotation is hindered by a projection 42a that engages with the axial groove 44a of the lead screw 38a. A functionally equivalent mechanism can be considered.

[0071] Valve 10 can be operated in the same manner as the valve in the embodiments described above. Furthermore, it should be noted that individual features described in relation to one embodiment may be implemented in other embodiments as needed. This is especially true of the functionality provided by the spring elements 47 and 54 described in relation to the embodiments shown in Figures 1 and 2. Next, embodiments from another perspective of the present invention will be listed. (1) A vacuum valve for medium vacuum, high vacuum, and ultra-high vacuum systems, wherein the vacuum valve is A valve housing that defines a passage connecting the first opening and the second opening of the valve housing, A valve body and a complementary seat arranged in the passage, wherein the valve body and complementary seat are provided with a sealing member, the valve body is movable in a linear axis direction along an open position and a closed position, and the valve body cooperates with the seat in the closed position to airtightly close the first opening, An electromechanical actuation unit for operating the valve body, wherein the actuation unit comprises an electric motor, an input unit driven by the electric motor, and a mechanical conversion unit having an output unit driven by the valve body, wherein the mechanical conversion unit converts the rotational output of the electric motor into linear motion of the output unit to move the valve body in the axial direction, and A vacuum valve equipped with a vacuum valve. (2) The mechanical conversion unit comprises a feed screw cooperating with a nut element, as described in (1) above, for the vacuum valve. (3) The output section is the vacuum valve described in (3) above, comprising the nut element. (4) A vacuum valve according to any one of (1) to (3) above, wherein at least one first elastic element is provided, which is supported by the valve housing and acts to push the valve body to a closed position in the axial direction when a force is applied to the valve body. (5) The valve body is movable in a linear axial direction relative to the output section, and is a vacuum valve according to any one of (1) to (4) above. (6) The vacuum valve according to (5) above, wherein the electromechanical operating mechanism is supported by the output section and comprises at least one second elastic element acting on the valve body such that a force is exerted on the valve body that propels it axially away from the output section. (7) The vacuum valve according to (5) above, wherein the output unit and the valve body are connected by a coupling unit that restricts the relative axial movement between the output unit and the valve body. (8) The vacuum valve described in (4) and (6) above, wherein the first elastic element has higher elasticity than the second elastic element. (9) The output section is a vacuum valve according to any one of (1) to (8) above, which is rotatably fixed and held by a guide device. (10) The vacuum valve according to (9) above, wherein the guide device comprises projections extending in the axial direction that cooperate with guide slots or grooves. (11) The vacuum valve according to any one of (1) to (10) above, wherein the electric motor and the input unit are driven-coupled via at least one reduction drive unit. (12) The vacuum valve according to any one of (1) to (11) above, wherein the electromechanical operating unit comprises at least one locking device and at least one locking function to lock the output unit or the valve body in a desired axial position. (13) The aforementioned mechanical conversion unit is a vacuum valve as described in (12) above, having self-locking properties. (14) A vacuum valve according to any one of (1) to (13) above, wherein a position sensor is provided to detect the position of at least one of the output unit and the valve body. (15) A vacuum valve for a medium vacuum system, a high vacuum system, or an ultra-high vacuum system, wherein the vacuum valve is A valve housing that defines a passage connecting the first opening and the second opening of the valve housing, A valve body and a complementary seat disposed in the passage, the valve body and complementary seat comprising a sealing member, the valve body being linearly movable between an open position and a closed position, wherein the valve body cooperates with the seat in the closed position to close the passage of the vacuum housing, the valve body and Complementary positions, An operating unit for operating the valve body, A sealing member having at least one of the following characteristics in a cross section perpendicular to the first opening: having a non-circular shape, being hollow, having a PTFE material or coated portion, or having a fluoroelastomer material or coated portion. The vacuum valve comprising the above. (16) The operating unit comprises an energy storage unit that supplies electrical energy to the electric motor. The vacuum valve according to any one of claims 1 to 15. (17) A method for operating a vacuum valve, wherein the vacuum valve is A valve housing that defines a passage connecting the first opening and the second opening of the valve housing, A valve body and a complementary seat arranged in the passage, wherein the valve body and complementary seat are provided with a sealing member, the valve body is movable in a linear axis direction along an open position and a closed position, and the valve body cooperates with the seat in the closed position to airtightly close the first opening, An electromechanical actuation unit for operating the valve body, wherein the actuation unit comprises a motor, an input unit driven by the motor, and an output unit driven by the valve body, wherein the mechanical conversion unit converts the rotational output of the motor into linear motion of the output unit to move the valve body in the axial direction, and In a method for operating the vacuum valve comprising, A method for operating a vacuum valve, wherein the electric motor is operated during the movement of the valve body to the closed position such that the speed of the valve body decreases at least on one side before and during contact between the valve body and the seat. (18) The method according to (17) above, wherein the electric motor is operated such that the movement of the valve body from the open position to the closed position takes longer than the movement of the valve body from the closed position to the open position. (19) The method according to (17) or (18) above, wherein the electric motor is operated such that the compression of the sealing member when the valve body moves to the closed position takes longer than the depressurization of the sealing member while the valve body is moving from the closed position. (20) The method according to any one of (17) to (19) above, wherein the electric motor is operated in the closed position of the valve body such that the force acting on the sealing member does not fall below a predetermined threshold. (21) The method according to (20) above, wherein the force acting on the sealing member is determined based on data provided by at least one of a force, strain, or temperature sensor. (22) The method according to (21) above, wherein the force acting on the sealing member is determined based on the operating variables of the electric motor. [Explanation of Symbols]

[0072] 10 Vacuum valve 12 cabinets 14 Bottom 16 Room 1 18. First opening 20. Second opening 22a, 22b Flange section 24 Wall elements 26 Wall section 28 Guidance device 32 Room 2 36 Reduction drive unit 38, 38a Lead screw 40, 40a nuts 42, 42a protrusion 44, 44a Axial slots or grooves 46 Sleeves 47 First spring element 48 Advanced Elements 50 Poppet 52, 52a, 52b Sealing part 54 Second spring element 56 Axial protrusion 58 Bellows 60 seats 62 belts 64, 66 Pulley 68 Rod part 70 Guidance Elements 72 Guide opening 74 Bearing support 76 Bearings 78 Output Gear 80 Input Gear 82 Groove 84 gaps 86 fingers 88 Groove 90a, 90b axis wall AM axis movement S Stroke RA1, RA2 Rotation axis D Diagonal P position t time SC seal contact SR, SR1 compression range MMC metal-to-metal contact StR stress relaxation F force

Claims

1. A method for operating a vacuum valve, wherein the vacuum valve is A valve housing that defines a passage connecting the first opening and the second opening of the valve housing, A valve body and a complementary seat arranged in the passage, wherein the valve body and complementary seat are equipped with a sealing member, the valve body is movable in a linear axial direction along an open position and a closed position, and the valve body cooperates with the seat in the closed position to airtightly close the first opening, An electromechanical actuation unit for operating the valve body, the electromechanical actuation unit comprises a motor, an input unit driven by the motor, and an output unit driven by the valve body, the mechanical conversion unit converts the rotational output of the motor into linear motion of the output unit to move the valve body in the axial direction, and the electromechanical actuation unit and In a method for operating the vacuum valve comprising, The electric motor is operated during the movement of the valve body to the closed position such that the speed of the valve body decreases at least on one side before and during contact between the valve body and the seat. The electric motor is operated such that the force acting on the sealing member does not fall below a predetermined threshold, and the valve body is operated in the closed position. A method for operating a vacuum valve, characterized in that the force acting on the sealing member is determined based on one of the operating variables of the electric motor.

2. The method according to claim 1, wherein the electric motor is operated such that the movement of the valve body from the open position to the closed position takes longer than the movement of the valve body from the closed position to the open position.

3. The method according to claim 1, wherein the electric motor is operated such that the compression of the sealing member when the valve body moves to the closed position takes longer than the depressurization of the sealing member while the valve body is moving from the closed position.

4. The method according to claim 1, wherein the force acting on the sealing member is determined based on data provided by at least one of a force, strain, or temperature sensor.

5. The aforementioned mechanical conversion unit includes a feed screw that cooperates with a nut element, The method according to claim 1, wherein the output unit comprises the nut element.

6. The method according to claim 1, wherein at least one first elastic element is provided, which is supported by the valve housing and acts to propel the valve body to the closed position in the axial direction when a force is applied to the valve body.

7. The method according to claim 1, wherein the valve body is movable in the linear axial direction relative to the output unit.

8. The method according to claim 7, wherein the electromechanical actuation unit is supported by the output unit and comprises at least one second elastic element that acts on the valve body such that a force is exerted on the valve body to propel the valve body in the axial direction away from the output unit.

9. The method according to claim 7, wherein the output unit and the valve body are connected by a coupling unit that restricts the relative movement of the output unit and the valve body in the axial direction.

10. The output unit is fixed in place by a guide device so as not to rotate. The method according to claim 6 or 8, wherein the guide device comprises a projection that cooperates with a guide slot or groove extending in the axial direction.

11. The electromechanical operating unit includes at least one of a locking device and a locking function to lock the output unit or the valve body in a desired axial position. The aforementioned mechanical conversion unit has self-locking properties. The method according to claim 1.

12. The sealing member comprises at least one of the following characteristics in a cross-section perpendicular to the first opening: having a non-circular shape, being hollow, having a PTFE material or coated portion, or having a fluoroelastomer material or coated portion. The method according to claim 1.

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