WO2016206966A1

WO2016206966A1 - Control device for a pneumatic piston-cylinder unit for moving a closing element of a vacuum valve

Info

Publication number: WO2016206966A1
Application number: PCT/EP2016/062854
Authority: WO
Inventors: Florian Ehrne; Daniel Seitz
Original assignee: Vat Holding Ag
Priority date: 2015-06-22
Filing date: 2016-06-07
Publication date: 2016-12-29

Abstract

The invention relates to a control device for a pneumatic piston-cylinder unit (7, 7'), which piston-cylinder unit has a closing cylinder chamber (18) and an opening cylinder chamber (17) for moving a closing element (5, 6) of a vacuum valve between a position in which said closing element is lifted off a valve seat and a position in which said closing element is pressed against the valve seat. Said control device comprises a closing control line (20) for connecting to the closing cylinder chamber (18) and an opening control line (19) for connecting to the opening cylinder chamber (17) and a valve apparatus, which comprises a plurality of control valves (12-14; 28-32). In order to move the closing element (5, 6) from the position in which the closing element is lifted off of the valve seat into the position in which the closing element is pressed against the valve seat, compressed air at a closing working pressure can be admitted into the closing control line (20) and the opening control line (19) can be vented in a closing switching position of the valve apparatus. The control device also has a force-closing control line (21), in which a pressure booster (24) is arranged. In a force-closing switching position of the valve apparatus, compressed air at a force-closing working pressure, which force-closing working pressure is output by the pressure booster and is greater than the closing working pressure and the system pressure, can be admitted into the closing control line (20) via the force-closing control line (21) and the opening control line (19) is vented.

Description

Steueru ngsvorrichtung for a pneumatic piston-cylinder unit for adjusting a closure member of a Vakuumventi ls

The invention relates to a control device for a pneumatic piston-cylinder unit, which has a closing cylinder chamber and an opening cylinder chamber for adjusting a closure member of a vacuum valve between a position lifted from a valve seat and a position pressed against the valve seat, wherein the Control device which is connectable to a compressed air supply line under a system pressure, a closing control line for connection to the closing cylinder chamber and a

Opening control line for connection to the opening cylinder chamber and a plurality of control valves comprising valve means and wherein the

Adjusting the closure member from the pressed to the valve seat position in the lifted position from the valve seat in an opening switching position of the valve means the opening control line is under an opening working pressure compressed air is acted upon and the closing control line is vented and for adjusting the closure member of the position lifted from the valve seat into the position pressed against the valve seat in a closing switching position of the valve device, the closing control line can be acted upon by pressurized air under a closing working pressure and the opening control line is vented. Furthermore, the invention relates to a

A vacuum valve comprising a closure member, a pneumatic piston-cylinder unit having a closing cylinder space and an opening-cylinder space for adjusting the closure member between a position lifted from a valve seat position and a pressed-on the valve seat position, and a control device to a under a system pressure compressed compressed air supply line can be connected and the one connected to the closing cylinder chamber closing control line and connected to the opening cylinder chamber opening control line and a plurality of control valves

comprising comprehensive valve means, wherein for adjusting the closure member can be acted upon by the pressure applied to the valve seat position in the position lifted from the valve seat in an opening switching position of the valve means the opening cylinder chamber via the opening control line with under an opening working pressure compressed air and the closing cylinder chamber vented via the closing control line is and for adjusting the closure member of the lifted from the valve seat position in the pressed to the valve seat position in a closed switching position of the valve means of the closing cylinder chamber via the closing control line with under a closing working pressure compressed air is acted upon and the opening-cylinder chamber vented via the opening control line.

For adjusting closure members of vacuum valves to close and open a vacuum valve, are usually used as actuators pneumatic piston-cylinder units. These are by means of pneumatic

Control devices, which have control valves, driven to pressurize or vent the corresponding cylinder chambers of the piston-cylinder units with compressed air from a compressed air supply line. The use of different directional control valves, for example 3/2-way valves or 5/3-way valves as control valves is known. It is also known to arrange a pressure reducer (= a pressure reducing valve) in a closing control line, through which the closing cylinder space of a piston-cylinder unit is urged to press the closing member against the valve seat, to the closing force regardless of the present one System pressure in the compressed air supply line to limit to a desired value.

In this way controlled vacuum valves with pneumatic piston-cylinder units are known in different designs. With L-valves, the opening of the vacuum valve takes place from its closed

State in which the closure member is pressed against the valve seat, via an intermediate position in which the closure member is lifted from the valve seat, but the valve seat is opposite, in an open position in which the valve opening is fully released. The adjustment of the closure member of the Closed position in the intermediate position and from the intermediate position in the

Open position can be done by separate piston-cylinder units or by a common piston-cylinder unit using appropriate slotted guides. Examples of such L-valves are from the US

6,899,316 B2, US Pat. No. 6,431, 518 B 1, US Pat. No. 7,066,443 B2 and US Pat. No. 201 1/01 7501 1 A1. In other types of vacuum valves opening and closing of the valve takes place only by an axial displacement of a valve rod on which the

Closing member is arranged. For example, such vacuum valves with auseinanderspreizbaren closure members, with wedge-shaped closure members or with three-dimensional sealing surfaces and seals may be formed.

Examples of such vacuum valves are US 4,052,036 A, US 201 3/0277590 A1, US 6,367,770 B1 and G B 2 205 926 B.

Are known types of vacuum valves, in which only a small closing force is applied to close the vacuum valve of the pneumatic piston-cylinder unit. If there is no large pressure difference in the two chambers separated from the vacuum valve, for example if one of the chambers is evacuated and in the other of the chambers a process gas under a relatively low pressure is introduced for carrying out a vacuum process, then the seal between the closure member and the

Valve seat thus a low contact pressure. The stress on the seal and therefore the wear of the seal is thereby reduced. If there is a higher differential pressure between the two chambers, this acts in the sense of a contact pressure of the closure member to the sealing seat, whereby the sealing of the valve is ensured in the event of a higher differential pressure. Such, designed in the form of a wedge valve vacuum valve is shown for example in US 6,367,770 B1.

Also working in this way vacuum valves with two closure members are known, which are pressed in the closed state of the vacuum valve to valve seats surrounding the opposite valve openings of the vacuum valve. Such a vacuum valve with two closure members and opposite Valve openings are disclosed, for example, in US 201 5/01 36236 A1. When one of the two chambers separated by the valve is vented while the other chamber and the valve interior are under vacuum, the closing member closing the vented chamber can not withstand the differential pressure and venting the interior of the vacuum valve, thereby passing through the other closure member the resulting differential pressure is more strongly pressed against the valve seat. Such automatic ventilation of the valve interior and differential pressure of the other closure member is not desired in al len applications. It may also be desirable to increase the tightness of the vacuum valve in the case of sealing against a larger applied differential pressure.

It is further known from US Pat. No. 7,036,794 B2 that the contact force acting on the closure member depends on a determined value for the

Differential pressure between the two vacuum chambers, between which the

Vacuum valve is arranged to adjust. To adjust the closure member between its open and closed positions are in particular pneumatic

Piston-cylinder units shown. For adjusting the force exerted by a pneumatic piston-cylinder unit, a pressure regulating valve is called, from which the system pressure acting in a pneumatic supply line is reduced to a corresponding desired value. Such pneumatic pressure control valves, in particular known as servo valves, but are relatively expensive and have a high air consumption during operation. From US 8,141, 847 B2 is a setting of the closure member

applied pressing force depending on a user-entered parameters or depending on a configuration of the vacuum valve or an operating mode of the vacuum valve. In addition to electrically acting actuators for adjusting the closure member and pneumatic piston-cylinder units are shown. The contact pressure is in turn set by means of pressure control valves which set the pressures acting in the two cylinder chambers to values predetermined by a control unit. The object of the invention is to provide an advantageous control device for a pneumatic piston-cylinder unit of a vacuum valve or an advantageous vacuum valve with such a control device, through which a low-wear operation of a vacuum valve is made possible in a cost effective manner. According to the invention, this is achieved by a control device having the features of claim 1 or by a vacuum valve having the features of claim 9. The valve device of the control device according to the invention has, in addition to the opening switching position and closing switching position, a force-closing switching position. In this connected during operation of the control device to the closing cylinder chamber of the piston-cylinder unit closing control line is pressurized with compressed air, which is under a relation to the closing working pressure and the system pressure increased force closing working pressure. The under the Kraftschließ-working pressure standing compressed air is from a

Booster delivered, which is installed in a power closing control line.

According to the invention thus two different discrete closed states are provided for the vacuum valve. If a seal against a high

Differential pressure is desired, which may be in particular atmospheric pressure, the force-closing switching position of the valve device is used. Since in this case a provided by a pressure booster force closing working pressure is used, which is above the system pressure in the compressed air supply line, the vacuum valve can have as actuator a relatively small design piston-cylinder unit, which brings space and cost savings. The closing switching position can be used when the vacuum valve is to close against a contrast lower differential pressure and the tightness of the vacuum valve is sufficient in the closed state in this way. The closing working pressure with which the closing cylinder chamber of the

Piston-cylinder unit is acted upon, this can on the system pressure or, preferably, on a contrast lower, by a pressure reducer of Control device delivered, in particular constant preset value. In many applications of vacuum valves in vacuum systems, for example, when used between two process chambers or between a transfer chamber and a process chamber is in the closed state of the vacuum valve between the two chambers connected by the vacuum valve in normal operation, no greater differential pressure. For example, the vacuum valve is used to shield a process gas, which is used in one of the chambers for performing a vacuum process, with respect to the other chamber, wherein the pressure of the process gas is for example in the mBar range. Only when normal operation is interrupted, especially when service is required, one of the two chambers is flooded with atmospheric pressure and the vacuum valve must seal the other chamber from the flooded chamber against the atmospheric pressure acting in the flooded chamber. Pneumatic pressure booster, also as pressure booster or pressure booster

referred to, are known. For example, the output pressure on the

increases twice the value of the input pressure, whereby the input compressed air is alternately compressed by the pistons of two piston-cylinder units. After every piston stroke, a switchover takes place through valves of the pressure booster. Also, pressure booster with larger pressure increases, for example, 1: 3 are known.

The system pressure in the compressed air supply line, which is the input of the

Printer booster is supplied, for example, can be in the range of 5 bar to 8 bar.

The force-closing control line, in which the pressure booster is arranged, preferably opens into the closing control line, wherein in the closing control line upstream of the junction of the force-closing control line, a check valve is arranged to prevent the output from the pressure booster force closing working pressure, for example against one in the closing control line

built-in pressure reducer. In the force-closing control line, a check valve is advantageously arranged downstream of the pressure booster, which prevents a closing working pressure present in the closing control line from the outlet side of the pressure booster when the pressure booster is not supplied with compressed air on the input side.

In an advantageous embodiment of the invention, the valve device of the control device further comprises a shut-off switching position. I n this are in connected to a piston-cylinder unit of the vacuum valve

State of the control device, a first closed volume, which comprises the opening cylinder space and an adjoining portion of the opening control line, and a second closed volume formed, which comprises the closing cylinder chamber and an adjoining portion of the closing control line. In this shut-off switching position of the valve device can thus be determined the currently present position of the piston of the piston-cylinder unit (against the present in the first and second closed volume pressure). Preferably, the shut-off switching position is taken automatically when the control of the control valves of the

Valve device fails. It can thus be provided in the event of failure of the control of the control valves of the control device, a safety function against uncontrolled adjustment of the closure member of the vacuum valve. For example, the shut-off switching position can also be used to transport the vacuum valve.

Further advantages and details of the invention are explained below with reference to the accompanying drawings. In this show:

1 to 4 are schematic representations of an example of a vacuum valve which is operable with a control device according to the invention, wherein FIG. 1 shows the vacuum valve in oblique view and FIGS. 2 to 4 cross sections in the closed position, the intermediate position and the open position of the closure members of the vacuum valve show;

5 shows a schematic cross section through a modification of the vacuum valve of FIGS. 1 to 4;

6 to 9 schematic representations of a control device according to the invention in the opening switching position, closing switching position, force closing switching position and shut-off switching position of the valve device of the control device;

Fig. 10 is a schematic diagram of a modified control device according to the invention in the shut-off switching position.

A vacuum valve, in connection with the one invention

Control device can be used is shown by way of example in FIGS. 1 to 4 schematically. The vacuum valve has a valve housing 1 with arranged in opposite walls of the valve housing valve openings 2, 3, which lead into an interior 4 of the valve housing 1. In the interior 4 of the valve housing 1, first and second closure members 5, 6 are arranged, which are supported by a piston-cylinder unit 7. The piston-cylinder unit 7 is attached to a valve rod 8, which is led out by a linear feedthrough from the interior 4 of the valve housing 1. The valve rod 8 can by means of a piston-cylinder unit 9, which is arranged outside of the valve housing 1 and on the piston of which

Valve rod 8 is mounted to be moved in its longitudinal direction. The piston-cylinder unit 7 has, in an inner space of the cylinder, pistons 10, 11, on each of which one is sealed off from the interior of the cylinder

led out piston rod is attached. At the protruding from the interior of the cylinder ends of the piston rods, the first and second closure members 5, 6 are attached.

In the closed state of the vacuum valve, the closure members 5, 6 take their closed positions, in which they by means of the piston-cylinder unit 7 to the Valve openings 2, 3 surrounding sealing seats are pressed, see. Fig. 2. To open the vacuum valve, the closure members 5, 6 are lifted by means of the piston-cylinder unit 7 of the valve seats, see. Fig. 3. In these

These intermediate positions of the closure members 5, 6 are the valve seats opposite, so that they the valve openings 2, 3 in the axial direction of the

Cover valve openings 2, 3 still cover. Starting from these intermediate positions, the complete opening of the vacuum valve by means of the piston-cylinder unit 9 takes place by the closure members 5, 6 by an axial

Displacement of the valve rod 8 are adjusted to their open positions in which they completely open the valve openings 2, 3.

The pneumatic lines with which the piston-cylinder units 7, 9 acted upon with compressed air or are not shown in the schematic figures 1 to 4, as well as other parts of the control devices for controlling the piston-cylinder units 7, 9. The compressed air lines to the piston-cylinder unit 7 can conveniently pass through the valve rod 8, as is known. For this purpose, for example, pipe pieces extending parallel to the valve rod 8 and passing through the cylinder space of the cylinder of the piston-cylinder unit 9 can project into the axial direction of the valve rod 8, sealed with end portions.

The vacuum valve could also have a plurality of piston-cylinder units 7, which are connected to each other or integrated into a common, attached to the valve rod 8 support unit.

The first and second pistons 10, 1 1 are in the embodiment of Figs. 1 to 4 as mentioned in a common interior of the cylinder of the piston-cylinder unit 7 is arranged. Instead, separate internal spaces for the pistons 10, 1 1 could be provided, as shown in Fig. 5. In the embodiment of FIG. 5, two piston-cylinder units 7, 7 'are thus formed. Incidentally, the training as described above with reference to FIGS. 1 to 4. In connection with an embodiment of a vacuum valve according to FIG

Control device explained with reference to Figs. 6 to 9. The pneumatic control device has a pneumatic valve device which comprises the control valves 12, 13 and 14 and the auxiliary control valve 15. The positions of the control valves 12 and 14 can be shown in the

Embodiment be electrically adjusted, but not one

are shown shown electrical control. The position of

Control valve 1 3 can be pneumatically adjusted in the embodiment shown by the auxiliary control valve 1 5 by the auxiliary control valve 15, either the system pressure of the supply line 16 via an auxiliary control line 35 to a control input 27 of the control valve 1 3 is applied or the auxiliary control line 35th via the auxiliary control valve 1 5 is connected to the environment. The position of the auxiliary control valve 15 can be electrically adjusted and is controlled for this purpose by the electrical control, not shown. The auxiliary control valve 1 5 could also be omitted and the position of the control valve 13 could be adjusted electrically via a control by the electrical control. Other types of adjustment of the valves 12, 13 and 14 are also conceivable and possible in principle, e.g. in a mechanical way. In the figures, only the pneumatic

Components of the control device shown.

The control valves 12 and 14 and the auxiliary control valve 1 5 are connected to a compressed air supply line 16, which is under a system pressure, which is for example in the range of 5 bar to 8 bar.

The interiors of the piston-cylinder units 7, 7 'are divided by the pistons 10, 1 1 each into an opening cylinder chamber 17 and a closing cylinder chamber 18.

To the opening cylinder chamber 1 7, an opening control line 19 is connected, which leads from the control valve 12 to the respective opening cylinder chamber 17. from Control valve 12 is also followed by a closing control line 20. In a first portion of the closing control line 20, a pressure reducer 22 and a

Check valve 23 installed, the function will be explained below. This first portion of the closing control line 20 is to the control valve 1 third

connected, from which a second portion of the closing control line 20 emanates, which opens into the respective closing cylinder chamber 18 (after a branch of the last portion of the closing control line 20). It can thus also be said that the control valve 13 is installed in the closing control line 20. From the control valve 14 is a force-closing control line 21, in which a

Printer booster and a check valve 25 are installed, whose functions are explained below. Downstream of the check valve 25 opens the

Kraftschließ control line 21 in the closing control line 20, and at a point downstream of the check valve 23. The junction is located in the

Embodiment between the check valve 23 and the control valve 1 third

In the exemplary embodiment, a pressure monitor 26 is connected to the second section of the closing control line 20. Other components, like more

Pressure monitor, manometer, on vent lines of control valve

connected mufflers, etc. can be provided are in the

Function sketches for the sake of simplicity but omitted.

In the illustrated embodiment, the control valve 12 is designed as a 5/3-way valve, the control valve 1 3 as a 5/2-way valve, the control valve 14 as a 3/2-way valve and the auxiliary control valve 1 5 as a 3/2-way valve. However, the use of other valves to form a control device according to the invention is possible, as will be explained below with reference to an alternative embodiment. In Fig. 6, the opening switching position of the valve device is shown, in which the respective opening cylinder chamber 17 is acted upon with compressed air and the respective closing cylinder chamber 18 is vented. For this purpose, the opening control line 19 via the control valve 12 with compressed air from the supply line 16th

acted upon, the pressure applied to the opening cylinder chamber 1 7. The respective closing cylinder chamber 18 is vented by the opening into the closing cylinder chamber 18 portion of the closing control line 20 via the control valve 1 3 is connected to the environment. This position of the control valve 1 3 is occupied by the control input 27 is acted upon by the auxiliary control valve 15 to the system pressure of the supply line 18. The closing control line 20 and the force-closing control line 21 are by the control valves 12, 14 of the

Supply line 16 separated.

The thicker lines in the illustration of the relevant lines in the figures symbolize the higher pressure level.

When the first and second closure members 5, 6 are pressed against the respective valve seat and the valve means is placed in the opening switching position, the closure members 5, 6 are lifted from the valve seats.

In the closed switching position shown in Fig. 7, the respective opening cylinder chamber 17 is vented and the respective closing cylinder chamber 18 is pressurized with compressed air, which is under a closing working pressure. For venting the respective opening cylinder chamber 17, the opening control line 19 is separated by the control valve 12 from the system pressure in the supply line 16 and connected via the control valve 12 to the environment. To pressurize the respective closing cylinder chamber 18 with compressed air, the subsequent to the control valve 12 portion of the closing control line 20 is acted upon via the control valve 12 with the system pressure of the compressed air in the supply line 16. From the pressure reducer 22, the system pressure on one of the pressure reducer 22nd

set value, which may for example be in the range of 3 bar to 5 bar. As long as the system pressure is above this value, that of the

Pressure reducer 22 output pressure constant. About the check valve 23 and further via the control valve 1 3, which the two connected thereto sections of the closing control line 20 in this switching position of Valve device connects, this closing working pressure is applied to the respective closing cylinder chamber 18.

The passage position of the control valve 13 is taken when the auxiliary control line 35 is vented, which takes place by means of the auxiliary control valve 1 5.

The system pressure of the supply line 16 is shut off by the control valve 14 from the force-closing control line 21. When the closure members 5, 6 are lifted from the valve seats and the valve device is placed in the closed switching position, the

Closing members 5, 6 moved up to their respective valve seat and pressed against these. In the force-closing switching position of the valve device shown in FIG. 8, the opening cylinder chamber 17 of the respective piston-cylinder unit 7, 7 'is vented, via the opening control line 19 and the control valve 12, which the opening control line 19th connects to the ambient pressure. The respective closing cylinder chamber 18 is acted upon by compressed air, which is under a Kraftschließ- working pressure. For this purpose, the adjoining the control valve 14 portion of the force-closing control line 21 is acted upon by the control valve 14 with compressed air from the supply line 16, which is below the system pressure. This compressed air is supplied to the input of the pressure booster 24. On the output side of the pressure booster 24 connected portion of the force-closing control line 21 is then the corresponding higher force-closing working pressure. The under this

Compressed air force-closing working pressure can reach via the check valve 25 and the control valve 1 3 in the respective closing cylinder chamber 1 8. The pressure with which the respective closing cylinder chamber 18 is acted upon is thus higher than the system pressure and thus of course higher than the closing working pressure of the respective closing cylinder chamber 18 in the closed switching position of

Valve device is supplied. The even higher pressure at the output of the pressure booster 24 is symbolized in FIG. 8 by an even greater line width.

A pressurization of the output side of the pressure reducer 22 in the force-closing switching position of the valve device is prevented by the check valve 23.

If in the off the respective valve seat positions of the

Closure members 5, 6, the valve means is placed in the force-closing switching position, the closure members 5, 6 at their respective valve seat

moved up and pressed against the respective valve seat. The pressing force is higher than in the closing switching position of the valve device. If the

Closure members 5, 6 are pressed in the closed-switching position of the valve device with the lower pressing force to its respective valve seat and the valve device is moved into the force-closing switching position, the

Pressing force of the closure members 5, 6 increases according to their valve seats accordingly.

The force closing working pressure is preferably twice or more than twice as large, e.g. three times as large as that in the supply line

present system pressure.

The pressure reducer 22 and the pressure booster 24 are thus connected in parallel. The respective closing cylinder chamber 18 can through the valve means of

Control device either with the delivered by the pressure reducer 22 closing working pressure or with the output from the Druckerhoher 24

Kraftschließ-working pressure are applied.

When using the control device with the embodiment of the vacuum valve shown in FIGS. 1 to 4 eliminates the branching of the last portion of the closing control line 20 in the parallel, opening to the two separate closing cylinder chambers branches and the closing control line opens into the common Closing cylinder space, which lies between the two pistons 10, 1 1. On the opposite sides of the two pistons 10, 1 1 are the opening cylinder chambers, in which the parallel branches of the opening control line 19 lead to the end-side branching of the opening control line 19. In the opened state of the vacuum valve according to FIG. 5 or according to FIGS. 1 to 4, two vacuum chambers connected to the two valve openings 2, 3 are connected to one another. When these two vacuum chambers are to be separated, with only a slight differential pressure between the two

Vacuum chambers is present, for example, less than 100 mBar, so can be taken to close the vacuum valve, the closing switching position of the valve device of the control device. If, by contrast, a higher differential pressure exists between the two vacuum chambers, for example of 1 bar, and / or higher demands on the seal between the two chambers, the vacuum valve can be closed by assuming the force-closing switching position of the valve device. Both

Closure members 5, 6 are pressed with the increased contact pressure on the valve seat, both closure members 5, 6 can withstand the present differential pressure and the respective valve opening 2, 3 seal. By this double seal can be achieved in this case also a particularly high tightness of the vacuum valve and increased safety.

The interior 4 of the valve housing 1 can usually be pumped off, which is not shown in the drawings. In the shut-off switching position of the valve device illustrated in FIG. 9, a first closed volume is formed, which comprises the two opening cylinder chambers 17 and the opening control line 19. Am of the

Opening cylinder chambers 17 remote end, the opening control line 19 is completed by the control valve 12. Subsequently, a second

formed closed volume, which includes the closing cylinder chambers 18 and an adjoining portion of the closing control line 20, which from the closing cylinder chambers 18 via the control valve 13 to the Check valve 23 is sufficient. This second closed volume includes in

Further, a portion of the force-closing control line 21 from its confluence with the closing control line 20 to the check valve 25. These closed volumes counteract a movement of the respective piston 10, 1 1, a restoring force.

The piston-cylinder unit 9 of the vacuum valve is of its own

operated pneumatic control device, which is not shown separately and may be formed in a conventional manner. It may be, for example, a 5/3-way valve, wherein in the middle switching position, a first closed volume comprising the opening cylinder space located on one side of the piston and a second closed volume comprising the closing on the other side of the piston. Cylinder space is formed. In the two other switching positions, the closing cylinder space is pressurized on the one hand and vented the opening cylinder chamber and vented to the other of the closing cylinder chamber and the opening cylinder chamber pressurized.

The control device according to the invention can also be used with other types of vacuum valves, for example those in the

Description in connection with the known prior art types of vacuum valves.

In particular, by means of a control device according to the invention, only a single piston-cylinder unit can be actuated in order to open and close the vacuum valve by adjusting the same.

A modified embodiment of the control device according to the invention is shown in FIG. The differences to the previously described

Embodiment of the control device will be explained below. Apart from the differences described below, the training corresponds to that of the first embodiment and to the local Description regarding the corresponding components and possible modifications is made.

The control device comprises here as a valve device, the control valves 28 to 32, which are all formed as 2/2-way valves. That in each case there is an input and an output, wherein the output is disconnected from the input in the closed state of the control valve and is connected to the input in the open state of the control valve. To the compressed air supply line, the control valves 28, 30 and 32nd

connected. From the control valve 28, the opening control line 19 goes out, which opens into the opening cylinder chamber 1 7. From the opening control line 19 branches off a vent line 33, which can be shut off via the control valve 31 or connected to the environment.

From the control valve 30 is connected to the closing cylinder chamber 18 closing control line 20, in which as in the embodiment previously a

Pressure reducer 22 and a check valve 23 are installed. Downstream of the check valve 23 branches off from the closing control line 20 from the vent line 34, which can be shut off by the control valve 29 or connected to the environment. From the control valve 32, the force-closing control line 21 goes out, in which, as described above, a pressure booster 24 and a check valve 25 are installed. The force-closing control line 21 opens downstream of the check valve 25 in the closing control line 20th

To take the opening switching position, the control valves 28, 29 are opened and the control valves 30, 31 and 32 are closed.

To take the closed switching position, the control valves 28, 29 and 32 are closed and the control valves 30, 31 are opened. To take the force-closing switching position, the control valves 28 and 29 are closed and the control valves 31 and 32 are opened. The position of the control valve 30 is preferably closed for safety reasons, but may also be open.

In the shut-off switching position of the valve device all control valves 28 to 32 are closed.

The functions in the individual switching positions of the valve device are analogous as previously described with reference to the embodiment of FIGS. 6 to 9.

Instead of the vent lines 33, 34 with the control valves 29, 31 3 and 2-way valves in the opening control line 19 and the closing control line 20 may be installed at the points of the branches of the vent lines 33, 34. In one position of the 3/2-way valves, the input would be connected to the output and in the other position, the input would be shut off and the output connected to a vent port of the control valve.

Various further modifications of the embodiments of the control device shown, for example, with regard to the design and arrangement of the control valves are conceivable and possible, without departing from the scope of the invention. For example, it would also be conceivable and possible to connect the force-closing control line directly to a connection of the piston-cylinder unit 7, 7 'which opens into the closing cylinder space 18. In the force-closing switching position, the closing cylinder chamber would then be acted upon directly via the force-closing control line with the force-closing working pressure (and via the closing cylinder chamber 18, then the section of the closing control line 20 connected to the closing cylinder chamber 18 with the force closure Working pressure applied). The pressure reducer 22 could basically be omitted. Instead of, preferably self-closing trained, check valves 23, 25 and accordingly controlled shut-off valves could be present.

Legend

to the reference numbers:

Valve housing 19 opening control line

Valve opening 20 closing control line

Valve opening 25 21 Power closing control line

Interior 22 Pressure reducer first closure member 23 Check valve second closure member 24 Pressure booster

, 7 'piston-cylinder unit 25 check valve

Valve rod 30 26 Pressure switch

Piston-cylinder unit 27 Control input

0 first piston 28 control valve

1 second piston 29 control valve

2 control valve 30 control valve

3 control valve 35 31 control valve

4 control valve 32 control valve

5 Auxiliary control valve 33 Vent line6 Compressed air supply line 34 Vent line 7 Opening cylinder space 35 Auxiliary control line 8 Closing cylinder space

Claims

Control device for a pneumatic piston-cylinder unit (7, 7 '), which has a closing cylinder chamber (18) and an opening cylinder chamber (17) for adjusting a closure member (5, 6) of a vacuum valve between a lifted from a valve seat Position and a pressed against the valve seat position, wherein the control device, which is connectable to a compressed air supply line (16) under a system pressure, a closing control line (20) for connection to the closing cylinder chamber (18) and an opening -Steuerleitung (19) for connection to the opening cylinder chamber (17) and a plurality of control valves (1 2-14; 28-32) comprising valve means and wherein len to Verstel

Closing member (5, 6) from the pressed to the valve seat position in the position lifted from the valve seat position in an opening switching position of the valve means the opening control line (19) under an opening working pressure compressed air is acted upon and the closing control line (20 ) is vented and for adjusting the closure member (5, 6) from the position lifted from the valve seat in the pressed position on the valve seat in a closed switching position of the valve means the closing control line (20) under a closing working pressure compressed air is acted upon and the opening control line (19) is vented, characterized in that the control device further comprises a force-closing control line (21) in which a pressure booster (24) is arranged, whose input, the system pressure of the compressed air supply line (16) can be fed and one of which is opposite

System pressure increased pressure can be dispensed, wherein in a force-closing switching position of the valve means the closing control line (20) via the force-closing control line (21) with one of the Druckerhöher

against the closing working pressure and the system pressure increased, force closing working pressure standing compressed air can be acted upon and the opening control line (19) is vented.

2. Control device according to claim 1, characterized in that in a shut-off switching position of the valve means a first closed volume, which comprises the opening cylinder chamber (1 7) and at least one adjoining portion of the opening control line (19), and a second closed volume can be formed, which comprises the closing cylinder space (18) and at least one adjoining portion of the closing control line (20).

3. Control device according to claim 1 or 2, characterized in that in the closing control line (20) a pressure reducer (22) is arranged to reduce the closing working pressure against the system pressure.

4. Control device according to one of claims 1 to 3, characterized

characterized in that in the closing control line downstream of the

Pressure reducer (22) a check valve (23) for preventing a

Actuation of the pressure reducer (22) is arranged with the force closing working pressure in the power closing Schaitstellung the valve device.

5. Control device according to one of claims 1 to 4, characterized

characterized in that the opening working pressure corresponds to the system pressure.

6. Control device according to one of claims 1 to 5, characterized

characterized in that the force-closing control line (21) opens into the closing control line (20).

7. Control device according to one of claims 1 to 6, characterized

characterized in that in the force-closing control line (21) downstream of the pressure booster (24), a check valve for preventing a Pressurization of the pressure booster (24) is arranged in the closed switching position of the valve device.

Control device according to one of claims 1 to 7, characterized

characterized in that the pressure booster (24) increases the pressure supplied to its input to double or triple the value.

Includes vacuum valve

a closure member (5, 6),

a pneumatic piston-cylinder unit (7, 7 '), which has a closing cylinder space (18) and an opening cylinder space (1 7) for adjusting the closure member (5, 6) between a position lifted from a valve seat and one at having the valve seat pressed position, and a control device which is connectable to a compressed air supply line (16) under a system pressure and the one to the closing cylinder space (18) connected closing control line (20) and one to the opening cylinder space (17) connected to the opening control line (19) and a plurality of control valves (12-14; 28-32) comprising valve means, wherein for adjusting the closure member (5, 6) from the pressed against the valve seat position in the position lifted from the valve seat in an opening switching position of the valve device, the opening cylinder chamber (1 7) via the opening control line (19) with below an opening working pressure stand Nder compressed air can be acted upon and the closing cylinder chamber (17) via the closing control line (20) is vented and for adjusting the closure member (5, 6) of the lifted from the valve seat position in the pressed to the valve seat position in a closed switching position the valve device of the closing cylinder chamber (18) is acted upon by the closing control line (20) with pressurized air under a closing working pressure and the opening cylinder chamber (1 7) is vented via the opening control line (19), characterized in that the control device further comprises a force-closing control line (21) in which a booster (24) is arranged, the input of which System pressure of the compressed air supply line (16) can be fed and from which a relation to the system pressure increased pressure can be dispensed, wherein in a force-closing switching position of the valve means of the closing cylinder chamber (18) via the force-closing control line (21) with the closing Control line (20) communicates with pressurized compressed air which can be acted upon by pressurized air (24) and increased in force compared to the closing working pressure and the system pressure, and the opening cylinder space (17) is actuated via the opening control line (17). 19) is vented.

Vacuum valve according to claim 9, characterized in that the

Vacuum valve, a first and a second closure member (5, 6) and a piston-cylinder unit (7) with first and second pistons (10, 1 1) or first and second piston-cylinder units (7, 7 ') with first and second piston (10, 1 1), wherein the first closure member (5) on a piston (10) mounted on the first piston rod (10) and the second closure member (6) on a second piston (1 1) mounted second piston rod is held.