EP0984170A2 - Fluid pressure cylinder, switch valve and pressure actuated work unit - Google Patents

Abstract

Pneumatic cylinder assembly has a direction change valve (V) and a system of bleed valves (24a, 24b) (27a, 27b) to pass pressure to the working zones of the cylinder (A) in a smaller valve structure. The pneumatic cylinder assembly, to convert pneumatic pressure into mechanical energy, has a let-off opening fitted with a valve (13a,13b) controlled by the pressure of the working medium at the feed opening. A direction change valve (V), and especially in a rocker valve structure, has at least one entry and one outlet for the working medium and a let-off channel between the valve unit and at least one outlet. The channel has an outlet and bleed control valve which is controlled electrically or by the pressure. The unit, which is operated by the pneumatic system, has a pneumatic working cylinder (A) with bleed valves (27a,27b), a direction change valve (V) and bleed control valves (24a,24b), and a pressure line (29a,29b) to each working zone of the cylinder (A).

Description

The invention relates to a pressure cylinder with a through Cylinder tube, at least one of the end pieces and a piston defined Work space, at least one supply opening for working medium to this Work space and a drain opening for the working medium from this work space, a valve, in particular for controlling such a pressure medium cylinder, with at least one input and at least one output for one Working medium and at least one control connection, or a switch valve, especially for controlling a double-acting pressure medium cylinder, with at least one connection and at least two outputs for a working medium as well as at least one control connection, as well as a work unit, comprising at least one pressure source for the working medium, at least one at most double-acting pressure medium cylinder, at least one valve for controllable supply of the working cylinder with working medium and at least a line for the working medium from the valve to the working cylinder.

For converting pneumatic energy into mechanical, for example Several functions are required by different performance Components, elements or component groups of the pneumatic work units here be performed. So the right of way signal is in a ventilation signal the corresponding working area of the working cylinder and, if necessary, a To convert ventilation signal of the counter chamber, or these signals are too link. In conventional constructions this is done by the valve accomplished that also for the diversion of the network compressed air to the appropriate Workspace, the opening of the counter chamber for cylinder ventilation and the Exhausts the exhaust air into the atmosphere. The line of both the network compressed air to the cylinder, which is purely the conversion of air pressure into mechanical Power over the cylinder piston, as well as the exhaust air from the cylinder into the atmosphere is carried through pneumatic lines. In doing so So far, the pneumatic cylinders have been ventilated via the same line and also vented, although these two processes required different cross sections. The used to control double-acting pneumatic cylinders So far, valves had to function both because of the deflection of the Pressure medium in the respective cylinder chamber as well as the ventilation control the respective counter chamber have very large sizes - while a lot Space in the end pieces of the pneumatic cylinder remained unused. Poses similarly the situation with hydraulic units.

The object of the present invention is therefore elements for a pressure-operated work unit and such an improved To create work unit itself, at least with a smaller size of the valve is reached, the existing space, especially in the cylinder better exploited and the performance of the individual elements better and can be coordinated more efficiently.

This goal becomes the first with a working cylinder at the beginning mentioned type according to the invention achieved in that the drain opening on Cylinder is provided with a valve through the at the feed opening applied pressure of the working medium is controllable. This creates a component group for a function of the pressure medium operated, for example pneumatic Working unit from the valve into the working cylinder, preferably in one of its end pieces, relocated where there is enough space anyway for the corresponding Built-in is available without leading to larger dimensions. The Valve itself, on the other hand, can be omitted for the exhaust or ventilation control necessary components can be reduced.

An even better use of space is advantageous Embodiment given in that the supply opening and the discharge opening directly connected to each other via a passage for the working medium stand and the valve is installed in this passage.

The optimal use of space in the working cylinder is possible if from the supply opening for the working medium parallel to the passage to the drain opening a supply channel to the work area runs out.

To meet the different requirements for ventilation The supply and discharge of the working medium is advantageous provided that the feed channel has a smaller cross section than that Passage to the drain opening. Now the ventilation or supply of the Working medium in a simple manner and without additional construction work the cheap small and the ventilation of the working cylinder or the Discharge of the working medium with the optimal large cross section.

Pneumatic systems can be advantageous and structurally very simple also the requirements of noise protection or hydraulic systems Flow phenomena are taken into account when the drain opening Throttle element and / or silencer is connected downstream.

According to an advantageous embodiment of the invention, the valve formed by a freely movable sealing element covering the passage, that at least partially covers the feed channel. So that is easier and the function of the ventilation control mentioned above is very reliable depending on the ventilation or the outflow of the working medium depending on the pressurization of the working area of the cylinder realizable.

The design of the working cylinder according to the invention is particularly advantageous, if it is designed as a double-acting cylinder, preferably at least functionally the same on both sides and on each Page is constructed in accordance with at least one of the preceding paragraphs because then the benefits mentioned are carried twice, for each side come.

The valve described at the outset, which is particularly suitable for actuation of a pneumatic working cylinder according to the invention is intended, according to a further feature of the invention characterized by a drain channel for the working medium, starting from a position between the locking element of the valve and the at least one output, wherein in this drain channel outlet or switchable by the pressure at the control connection Vent control valve is provided. This channel can be in the valve housing itself or one of the elements present in the valve and does not lead to an increase in its dimensions. The valve must therefore only be so large that the absolutely necessary connections and Controls are housed so that by this function optimization the smallest possible size is achieved.

For a double-acting cylinder is advantageously a Switch valve provided as described in the introduction, characterized by each at least one drain channel from a position between the valve element and each output, with in each drain channel at least one by the Control connection applied pressure switchable outlet or vent control valve is provided. This gives the same benefits as mentioned earlier for achieved an arrangement in which the network air connection bwz. Connection of the source for the print medium alternately to one of the two working chambers of the Working cylinder must be connected. The same applies in principle to a electrically switchable outlet or vent control valve.

According to a particularly advantageous embodiment, a Rocker valve designed with a switch valve through which on the control connection applied pressure switchable between two switch positions Rocker sealing element provided that the outlet or vent control valve via at least one device for transmitting the at the control connection applied pressure is in operative connection with the control room. This is at this valve construction with the smallest damaged spaces and even for large ones Mouth cross sections fast switching times and exact sealing immediate, safe and rapid ventilation control or control of the Ensure that the pressure medium flows out of the working cylinder. Because of the small rotary movements of the rocker sufficient for switching can do this Valve according to the invention can be built very small and flat and can have layers, both when assembling and if necessary Repair allows a very simple execution of the work. With the design of the switch valve according to the invention is a smaller size accessible as even with two rocker valves for a 5/2-way function.

It is advantageously provided that as a device for transmission of pressure a flexible part of the wall of the control room Membrane is provided, which is preferably on the valve stem Actual sealing element acts that blocks or releases the drain channel. This is a structurally simple and very space-saving manner particularly good switchability of the exhaust or vent control valve guaranteed.

Of course, with optimal use of the existing Space and for both sides, for which control is necessary, the The advantages mentioned above can be doubled if the switch valve is on has at least functionally the same structure on both sides.

A pneumatic work unit according to the invention comprises at least one Pressure source for the working medium, at least one pneumatic working cylinder, at least one valve for the controllable supply of the working cylinder with working medium and at least one line for the working medium from Valve to the working cylinder, and is for the function-optimized design of the individual elements, the better use of space and component reduction or. Reduction and better performance tuning of the elements characterized in that only one line per working space of the cylinder provided for the working medium to the cylinder and the lines over at least a controllable outlet or vent valve can be vented or relieved are that the working cylinder according to at least one of the above paragraphs trained and its drain opening is kept clear.

The best possible and structurally simplest combination of loading and Venting function or supply and discharge of the working medium can be achieved for example, provided that at the control port of the exhaust or vent valve the control pressure of the valve is present.

Preferably and with additional achievement of the advantages mentioned there the work unit is characterized by a valve arrangement a drain channel for the working medium, starting from a position between the blocking element of the valve and the at least one output, wherein in this drain channel is switchable by the pressure applied to the control connection Exhaust or vent control valve is provided.

The pneumatic work unit with the at least one double-acting, pneumatic cylinder is according to an advantageous embodiment characterized in that per working space of the cylinder only ever a line for the working medium to the cylinder provided that the working cylinder according to at least one of the paragraphs based on it and that a Switch valve arrangement according to at least one of the above, placed thereon Paragraphs is provided.

According to a further feature of the invention is in or on the working cylinder a control logic arrangement is provided, the connections for communication, preferably a fieldbus, electrical control and supply and for that Has working medium. This is a further increase in the compactness of the Unit of work possible with still increased versatility.

Of course, according to a further feature of the invention Valve for controlling one or both working areas of the working cylinder directly attached to it or integrated into it, preferably in one of the two end pieces of this cylinder.

Likewise, the or each vent control valve can advantageously attached to the working cylinder and / or the switch valve or in this be structurally integrated. In both cases, the result is as far as possible Simplification in assembly and arrangement at the installation site. Furthermore can thus lines between these combined components and in In case of structural integration also connection and sealing points omitted, which on the one hand, the arrangement of the overall system is essential simplified and its functional reliability - due to the lower risk of Leakages - can be increased significantly. The options just mentioned are also in the design of the switch valve in rocker valve design advantageously applicable.

In the following description, some exemplary embodiments of pneumatic variants with reference to the accompanying drawings are explained, but these examples are in no way a limitation to the general inventive idea set out in the claims are values.

Fig. 1 shows a longitudinal section through an inventive Working cylinder, Fig. 2 is a partial cross-sectional view of a switch valve according to the invention with integrated ventilation control valves, Fig. 3 shows a possible embodiment of the integrated in the switch valve Vent control valves, Figures 4 and 5 are schematic circuit diagrams of pneumatic working units according to the invention, Fig. 6 sets Switch valve in rocker valve design together with the associated bleed control valves and Fig. 7 is a switch valve in rocker valve design with integrated vent control valves.

The pneumatic working cylinder A shown in Fig. 1, preferably actuated with compressed air as the working medium, consists of a cylinder tube 1, the ends of which are closed by a base 2 and a cover 3. In A piston is displaceable by this working cylinder A through the working medium 4 out, which via a piston rod 5, which is sealed by the cover 3 is passed, the mechanical force on the element to be driven transmits. Of course, the invention is based on in the same way rodless cylinders and working media other than compressed air applicable, for example also on hydraulic working media.

Between the bottom 2 and piston 4 is, for the double-acting shown Working cylinder A, a first working space 6 defined and between the Cover 3 and the piston 4, a second working space 7, depending on the exposure with the working medium and the vent in the direction of movement of the piston 4 located work space a vented counter chamber represents the current working space under pressure. The compressed air is the work spaces via connections 8a, 8b, which into the feed openings 9a, 9b are used, supplied, with them through the supply channels 10a, 10b relatively small cross-section reaches the work rooms 6, 7. Parallel to These feed channels 10a, 10b each have one of the feed openings 9a, 9b Passage 11a, 11b out, leading to two discharge openings 12a, 12b for the air the work rooms 6, 7 leads. There are none at these drain openings 12a, 12b Lines connected, but they lead directly or preferably over a silencer or a speed control throttle and one subsequent silencers (both indicated) in the atmosphere.

The mouth of the passage 11a, 11b lying in the feed opening 9a, 9b forms a valve seat for a located in the feed opening 9a, 9b preferably flat valve element 13a, 13b that completely this mouth covered and advantageously also the mouth of the parallel Feed channels 10a, 10b to work space 6 and 7, at least partially covered. If, for example, in the work space 6 via the assigned, in compressed air is supplied to the drawing 8a on the right thereby pressing the right valve element 13a onto its seat and sealing the Passage 11a to the right drain opening 12a. The compressed air arrives on Valve element 13a past into the feed channel 10a and further into the work area 6. This causes the piston 4 to move to the left and the Piston rod 5 extends. If at the same time the left connection causes is depressurized via a vent control valve, this piston movement can in the working chamber 7 which now represents the counter chamber, the left valve element 13b lift off its valve seat, whereby the passage 11b is released and the air from the counter chamber into the atmosphere through the exhaust port 12b can flow out.

Conversely, as soon as the right port 8a is depressurized and the left Connection 8b is supplied with compressed air, the situation is reversed and the left valve element 13b seals the passage 11b so that the compressed air is safely directed only into the work room 7. On the opposite side presses back the forced air from the now counter chamber 6 the valve element 13a high, as soon as the connection 8a is depressurized and the air can over the passage 11a and the drain opening 12a escape. For liquid working media other valve designs may be useful and necessary, but what nothing changes in the principle and mode of operation.

With such a working cylinder A with integrated pressure relief or. Venting can be done with valve V, for example in the version of Fig. 2, the vent valve arrangement avoided and the size accordingly be made smaller. In the housing 14 of the valve V is the real thing Valve element 15 slidably mounted, which valve element 15 in itself known way a compressed air connection 16 alternately with the two Working connections 17a and 17b connects which working connections 17a, 17b via pressure lines and the connections 8a and 8b on the working cylinder A thereof Supply working rooms 6 and 7 with compressed air. The valve element 15 acted upon by a control pressure, which via the control connections 18th is initiated.

To now in a simple way the vent control function for the pressure lines to the connections 8a and 8b on the working cylinder into the valve can integrate, according to one embodiment of the valve, a drain channel 19 be provided from a position between the corresponding output 17a, 17b of the valve V and the actual valve element 15 to a drain opening 19a leads into the atmosphere. This drain channel 19 is through a Valve element 20 closed as long as the associated outlet with the compressed air source connected is. As soon as the control signal to switch the direction of movement comes in Fig. 3 by loading the space 21 with the Control pressure, the valve element 20 of its valve piston 20 Lifted the seat and gives the connection from the drain channel 19 through the drain opening 19a released into the atmosphere. The pressure line is then depressurized and in the working cylinder A, the valve element 13a, 13b by the from the previously lifted with compressed air and the corresponding Ventilated work area.

Of course, the ventilation function just described can also by separate vent control valves 24, as shown in FIG Fig. 4 is shown, the working air lines by solid lines and the control air lines are symbolized by dashed lines. At The pneumatic working unit shown here is the compressed air source 25 connected to the working cylinder A via a switch valve V. The working cylinder A has two vent valves 27a and 27b, for example as in FIG 1, integrated.

The control air lines 28a, 28b lead both to the switch valve V and also to the two vent control valves 24a, 24b, the drain lines in block or release the compressed air lines 29a and 29b to the working cylinder A. If, for example, the right control air line 28a with the control pressure is applied, the switch valve V gives the compressed air connection to right working space 6 of working cylinder A free. At the same time, since the Pilot pressure in parallel to this also on the right ventilation control valve 24a is placed in a position in which the connection of the left compressed air line 29b released to the atmosphere and this line is therefore depressurized. The vent valve 27b is thus also released and the left work space 7 can be vented to the atmosphere. The left bleed control valve 24b is in because there is no pilot pressure the closed position.

Instead of two vent control valves 24a and 24b, as in FIG. 5 shown, a single vent control valve 30 may also be provided, whose two inputs each with one of the two pressure lines 29a and 29b are connected and its exit leads into the atmosphere. The bleed control valve 30 is, for example, a conventional 3/2-way valve, as well like the switch valve V. If the left control line 28b with the control pressure is acted upon, the compressed air from the compressed air source 25 passes through the Pressure line 29b to the left work space 7. At the same time the vent control valve due to the control pressure applied here in parallel Positioned in which the right pressure line 29a via the bleed control valve 30 vented into the atmosphere and thus depressurized. In order to the right ventilation valve 27a in the working cylinder A is relieved and the Air can escape from the right-hand work space 6, which is therefore a vented counter chamber is to escape into the atmosphere via this valve 27a.

An advantageous embodiment for the switch valve is in FIG. 6 shown. In this embodiment, a rocker valve is used as a switch valve W provided. An essentially rigid, movable about an axis of rotation Seesaw 31 from e.g. Metal is stored in a valve housing 32. The seesaw 31 is for example between two elastomer sealing elements 33 - for higher ones Preferably press reinforced - embedded and and the axis of rotation D swiveling. The housing 32 has at least one supply connection Connection to the compressed air source 25 and two working connections on, of which the pressure lines 29a, 29b go out to the working cylinder A. If over the control line 28a applies a pilot pressure of a magnitude to the the right part of the rocker 31 exerts a force which is greater than that by exerted the supply pressure at P on the right leg of rocker 1 Force, the rocker 31 together with the elastomer sealing elements 33 in the 6 shown position in which the rocker 31 moves the right valve seat closes and the compressed air source 25 via the left working connection via the pressure line 29b with a working space of the working cylinder A connects. The other work connection is closed. Because the control line 28a also acts on the ventilation control valve 24a with the control pressure, this opens the connection from the right pressure line 29a to the atmosphere and thus depressurises this line, which also causes the right vent valve Open 27a in working cylinder A and the corresponding working space in can vent the atmosphere.

Particularly small and to achieve a pneumatic work unit with as few components as possible is the embodiment of the rocker switch valve W of Fig. 6 or 7 advantageous. In the housing 32 is a Insert E with two bleed control valves installed. The control rooms 34a, 34b for the actuation of the rocker 31 are each with a flexible Membrane 35 sealed opening, through which membranes 35 the pressure prevailing in the control chamber 34a, 34b for actuating the sealing elements 36a, 36b of the ventilation control valves is transferred to them, preferably via the valve stems 37a, 37b. From the work ports too The discharge lines 38a, 38b lead past the rocker to the pressure lines 29a, 29b 31 to the vent control valves and further to drain openings in the The atmosphere. In the position shown of the rocker switch valve W with Actuation of the left control chamber 34b with the control pressure would Control pressure also via the membrane 35b and the valve stem 37b the valve element Lift 36b of the left bleed control valve from its valve seat and release the drain channel 38b. The left working connection is in this Position against the compressed air source 25 completed, but is on the Drain channel 38b vented into the atmosphere and thus depressurized. The Right working connection of the pressure line 29a is with the compressed air source 25 in connection and supplies one of the working spaces of the working cylinder Compressed air. The right vent control valve holds the drain passage 38a closed.

Of course, some or all of the elements mentioned can fluid-operated work unit combined in a single component be, which is as far as possible a simplification in assembly and Arrange at the installation location. For example, the valve for Control one of the two work rooms or also for double-acting A possible switch valve to control both workrooms directly attached to the working cylinder or integrated into it, preferably in one of the two end pieces of this cylinder. That too or each bleed control valve can be attached to the working cylinder in the same way and / or the switch valve is attached or even integrated into it his. This eliminates lines between these combined Components and in the case of structural integration also connecting and Sealing points, with which the arrangement of the overall system is essential simplified and its functional reliability - due to the lower risk of Leakages - can be increased significantly. The options just mentioned are also in the design of the switch valve in rocker valve design advantageously applicable.

An expansion of the application possibilities and an increase in the number of possible work processes can be achieved with a very compact arrangement be a control logic arrangement in or on the working cylinder A. is integrated. This can be flanged to the working cylinder or a preferably one of its end pieces can be integrated. From the central Control units go connecting lines to this control logic arrangement in the or on the working cylinder, that of communication, electrical control, serve the energy supply and the supply with the working medium. As A fieldbus is preferably provided for the communication system. The Control logic arrangement can also be control signals or position signals, for example End position or position sensors in or on the working cylinder or from evaluate these actuated elements and take appropriate actions to trigger them control the control valves or these signals and actions via the Report back communication lines to the control unit.

Claims (20)

Pressure medium cylinder with at least one working space (6, 7) defined by the cylinder tube (1), at least one of the end pieces (2, 3) and a piston (4), at least one supply opening (9a, 9b) for working medium to this working space ( 6, 7) and a drain opening (12a, 12b) for the working medium from this work space, characterized in that the drain opening (12a, 12b) on the cylinder (A) with a valve (13a, 13b; 27a, 27b ) is provided, which can be controlled by the pressure of the working medium applied to the feed opening (9a, 9b). Cylinder according to claim 1, characterized in that the feed opening (9a, 9b) and the drain opening (12a, 12b) directly via a passage (11a, 11b) for the working medium in connection with each other and the valve (13a, 13b) is installed in this passage. Cylinder according to claim 2, characterized in that from the feed opening (9a, 9b) for the working medium parallel to the passage (11a, 11b) a supply channel (10a, 10b) to the work space for the drain opening (12a, 12b) (6, 7) goes out. Cylinder according to claim 3, characterized in that the feed channel (10a, 10b) a smaller cross section than the passage (11a, 11b) Has drain opening (12a, 12b). Cylinder according to at least one of the preceding claims, characterized characterized in that the drain opening (12a, 12b) is a throttle element and / or muffler is connected downstream. Cylinder according to at least one of claims 3 to 5, characterized in that that the valve is moved by a freely movable passage (11a, 11b) covering sealing element (13a, 13b) is formed, which preferably at least partly also covers the feed channel (10a, 10b). Cylinder according to at least one of the preceding claims, characterized characterized that it is designed as a double-acting cylinder, preferably at least functionally the same on both sides each side built according to at least one of the preceding claims. Valve, in particular for controlling a pressure medium cylinder according to at least one of the preceding claims, with at least one Input (16) and at least one output (17a, 17b) for a working medium and at least one control connection (18), characterized by a drain channel (19, 19a) for the working medium, starting from one Position between the blocking element (15) of the valve (V) and the at least an outlet (17a, 17b), one in the outlet channel through the Switchable outlet or pressure at the control connection (18) Vent control valve (20, 22) is provided. Valve, in particular for controlling a pressure medium cylinder according to at least one of claims 1 to 7, with at least one input (16) and at least one outlet (17a, 17b) for a working medium as well at least one control connection (18), characterized by a drain channel (19, 19a) for the working medium, starting from one position between the blocking element (15) of the valve (V) and the at least one Output (17a, 17b), an electrically switchable in this drain channel Exhaust or vent control valve (20, 22) is provided. Switch valve, especially for controlling a double-acting Pressure cylinder according to at least one of claims 1 to 7, with at least one connection (16) and at least two outputs (17a, 17b) for a pressure medium and at least one control connection (18) by at least one drain channel (19, 19a) of one Position between the valve element (15) and each outlet (17a, 17b), wherein in each drain channel (19, 19a) at least one each by the Control connection (18) applied pressure switchable outlet or vent control valve (20, 22) is provided. Switch valve according to claim 10, wherein the switch valve as a rocker valve with a pressure between the pressure at the control connection two switch positions switchable rocker sealing element (31, 33) and at least one control space delimited by the rocker sealing element (34a, 34b), characterized in that the outlet or Vent control valve (36a, 36b) via at least one device (35a, 35b; 37a, 37b) for the transmission of the applied at the control connection Pressure is in operative connection with the control chamber (34a, 34b). Switch valve according to claim 11, characterized in that as a device to transmit the pressure one, part of the wall of the Control space (34a, 34b) forming flexible membrane (35a, 35b) is provided which is preferably via a valve stem (37a, 37b) to the actual Sealing element (36a, 36b) acts on the drain channel (38a, 38b) locks or releases. Switch valve according to at least one of claims 10 to 12, characterized by a structure that is at least functionally the same on both sides. Pressure medium-operated work unit, comprising at least one pressure source (25), at least one pressure medium cylinder (A), at least one valve (V) for the controllable supply of the working cylinder with working medium and at least one line (29a, 29b) for the working medium from the valve to the working cylinder, characterized in that per working space (6, 7) of the cylinder (A) only one line (29a, 29b) for the working medium provided for the cylinder and the lines via at least one controllable outlet or vent valve (24a, 24b; 30) can be relieved or can be vented that the working cylinder (A) according to at least one of claims 1 to 7 and its drain opening (12a, 12b) is kept free. Working unit according to claim 14, characterized in that at the control connection of the outlet or vent valve (24a, 24b; 30) the control pressure of the valve (V). Working unit according to claim 14, characterized by a valve arrangement according to claim 8 or 9. Pressure medium-operated work unit, comprising at least one pressure source (25), at least one double-acting pressure medium cylinder (A), at least one valve (V) for the controllable supply of the pressure medium cylinder with working medium and at least one line (29a, 29b) for the Working medium from the valve to the working cylinder, characterized by that only one line per working space (6, 7) of the cylinder (A) (29a, 29b) for the working medium to the cylinder provided that the Working cylinder (A) formed according to at least one of claims 1 to 7 and that a switch valve arrangement (V, W) according to at least one of claims 10 to 13 is provided. Pressurized unit according to one of claims 14 to 17, characterized in that a control logic arrangement in or on the working cylinder (A) is provided, the connections for communication, preferably a fieldbus, electrical control and supply and for has the working medium. Pressure-operated work unit according to one of claims 14 to 18, characterized in that the valve (V, W) for controlling one or both working areas of the working cylinder (A) directly attached to it or is integrated therein, preferably in one of the two end pieces (2, 3) of this cylinder (A). Pressurized unit according to one of claims 14 to 19, characterized in that the or each vent control valve (20, 22; 24a, 24b; 30; 36a, 36b) to the working cylinder (A) and or or that Switch valve (V, W) is attached or is structurally integrated in it.

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