SI9720033A - Pneumatic cylinder, in particular for actuating fume extraction valves in fume and heat extraction plants - Google Patents

Abstract

A pneumatic cylinder for actuating fume extraction valves in fume and heat extraction plants has a piston (2) that may be actuated from both sides with at least one working surface and that can be made to slide by pressurised air in a cylinder (1) with at least one working chamber (4), as well as an energy accumulator with regulating means. The regulating means can be controlled by control means to open or keep open the fume extraction valves. In order to obtain a compact pneumatic cylinder for a fume and heat extraction plant which is easy to install, a storage chamber in which air or pressurised air is stored as compressible pressure medium is provided as energy accumulator. The storage chamber is in communication with a compression surface (7) of the piston (2), at its side opposite to the working surface (7), so that pressure medium may flow between the storage chamber and the compression surface (7). The controller actuates a venting valve in communication with the working chamber (4) so that pressurised air may flow between the venting valve and the working chamber (4).

Description

PNEUMATIC CYLINDER SPECIFICALLY FOR SMOKE DRAINING

SHUTTER IN SMOKE AND HEAT EXTRACTION PLANTS

The invention relates to a pneumatic pressure cylinder, especially for the operation of smoke exhaust flaps in smoke and heat extraction plants, as claimed in claim 1.

A pressure tank with a double acting piston with at least one work surface, which moves in the cylinder with at least one work chamber by means of compressed air, e.g. in smoke and heat extraction plants (abbreviated RWAs / in German: Rauch-und Waermeabzuganlagen /) in the event of heat by opening the smoke and thermal exhaust flaps automatically or remotely controlled by compressed air acting during the collection and cylinder working chamber, especially in cases where these solutions are difficult or disabled. This provides a central approach to addressing this issue. In addition, by opening the vent flaps of heat and smoke, avoid rising temperatures due to congestion. The built-in pneumatic cylinder must meet high safety requirements. With this in mind, it is also important that the pneumatic cylinder with its associated lever is capable of operating, inter alia, in the most difficult safety conditions. In addition, a special final locking is provided for blocking the pneumatic cylinder piston rod intermediate. It is characterized in that it is coaxial to the piston rod on its opposite side from the stroke limiter and, with respect to the piston rod, an additional locking rod is provided. This restricts the partial stroke of the piston rod and protrudes outward from the locking piston arranged in the locking cylinder (EP 0363575 BI). An additional locking piston is movable in the locking cylinder which, by means of a bush-shaped section and balls, consolidates the partial adjustment of the stroke via the annular groove in the additional locking rod, into which the balls are radially movable. The radially outward movable beads are released when the bush-shaped section is axially withdrawn. In the event of a preset pressure exceeding, the additional locking piston is connected via a pressure-controlled control valve to the next nearby cylinder space. This interlock of some intermediate setting consists of ball-locked end-locking elements which are fed into the groove on the piston rod via a pressure-relieved locking piston.

The above-mentioned safety requirements, which must be met by the built-in pneumatic cylinder, to open the smoke outlet flap and keep it in the open position even in the event of a fire, are reliably secured by the final locking mechanism for fixing the position of the connecting lever. In order to achieve reliable opening of the smoke outlet flaps even in the case of fire, the RWA devices operated by means of a pressure medium are operated via a fire line pipe connection. The use and installation of such a fire retardant pipe line entails additional costs.

Another well-known possibility of fireproofing the construction of RWA devices with pneumatic cylinders is such that a pneumatic cylinder equipped with a gas pressure spring is used.

This gas pressure spring is not sufficiently reliable with regard to its use for these purposes and in difficult circumstances.

In addition, it is possible for a pneumatic cylinder to be coupled to a mechanical spring having such a spring force in the case of smoke and heat extraction devices that, in the event of a fire, it can move the smoke exhaust flap together with the moving parts of the pneumatic cylinder to the open position. Due to this additional spring, the pneumatic cylinders of the smoke and heat extraction devices are uncomfortably long.

In the present invention, therefore, the basic task is to find such a compact pneumatic cylinder for use in RWA devices, which will be able to pass without additional auxiliary power and without additional external pipe lines and which can be grasped and easily integrated into RWA devices without additional auxiliary energy and without additional external special fire extinguishers of pipework.

This task is solved by the implementation of a pneumatic cylinder, the characteristics of which are presented in the characteristic part of the first patent claim.

This pneumatic cylinder goes without additional auxiliary energy, as it is powered only by the compressed pressure medium, which is in particular compressed air, for normal operation. In normal operation, this pneumatic cylinder especially compresses the air trapped in the sump chamber in order to close the smoke outlet flaps, where it forms a kind of air spring in connection with the piston. To open the smoke outlet flaps, especially in the event of fire, only the working pressure of the piston vent must be released and the piston will be displaced by the compressed air pressure in the collecting chamber so that the flue outlets open. This mode of operation assumes that the collecting chamber adjacent to the work surface opposite to the (compression) side of the piston is sufficiently pre-filled with air that the piston can then sufficiently compress the air in the collecting chamber due to pressure on its work surface. The pressure generated in the collecting chamber depends on the ratio of the piston working surface to its compression surface, the working surface being particularly smaller, and on the stroke of the piston or its displacement volume as it moves from one extreme position to another. In this operation, it is certainly assumed that under unchanged ambient conditions (temperature), especially during successive piston strokes, there is no possibility of loss of air in the sump chamber.

In the case where a pneumatic cylinder is installed in the RWA devices which assumes an angle of opening of the smoke outlet flaps, which is generally 90 degrees, due to gravity, the gearbox is larger than the openings, e.g. up to 140 degrees, the piston rod of the pneumatic cylinder is automatically pulled along with the usual connecting elements. In this way, air is sucked into the collecting chamber, partially balancing the previous loss of pressure medium. An exemplary design measure by which this suction effect is specifically used in the recently discussed high angle opening RWA devices is given in claim 11.

Therefore, in particular for said specific RWA devices, the pressure medium addition device is structurally simple in that it is used as a pressure medium device to use a pressure valve built primarily into the bottom of the cylinder or into the cylinder wall. Through it, the space of the cylinder, which is separated from the work chamber, connects with the outside atmosphere. Through this pressure valve, the intake manifold can be filled by the suction of air from the outside atmosphere, under normal use of the pneumatic cylinder. In addition, the compact design of the pneumatic cylinder has been achieved.

Alternatively, as a device for adding pressure medium according to claim 7, the working chamber and from it a separate cylinder space may be connected to a flow path into which a mechanically automatically controlled pressure differential limiter is arranged. In this case, the end position of the piston shall be determined, in particular by the limiter, and the compression of the compressed air contained in the sump chamber shall be maximized. The air path towards the working chamber opens when the pressure differential between the working chamber and the collecting chamber exceeds a preset value on the pressure differential limiter. This results in a partial pressure offset, which automatically complements the loss of pressure medium in the collecting chamber.

In detail, this variant of the pressure medium addition device is preferably compactly arranged in the piston according to claim 8. Here, a first slide valve and a non-return valve as a pressure differential limiter are arranged in the piston to open the flow path in the piston between the working chamber and separated by a separate cylinder space. Here, the first slide valve operates by means of a handpiece arranged in the sump chamber of the cylinder space. The flow path in the piston opens when the piston with the first slide valve or. especially with its piston, it fits against the limiting or corresponding solid surface and the pressure differential between the working chamber and the cylinder space exceeds the preset value on the check valve.

A feature of the preferred embodiment of a pneumatic cylinder is that it has a non-return check valve as a second slide valve and a second slide valve, as well as a first slide valve with its projecting shaft coaxially co-inserted one after the other into a common bore in the piston. At one end, a cartridge is inserted and a pressure spring distributed between the first and second sliding valves presses the two inwards towards the sealing surfaces. This variant is especially recommended with regard to the design of pistons with only one bore for both sliding valves with few components, which is advantageous for production.

Particularly good sealing is achieved if the first and second slide valves are designed as rubber moldings with specially shaped sealing beads on their outer front faces.

The function of the first slide valve arranged in the piston assumes that the movement of the piston is limited by a stop or a correspondingly solid contact surface. This restraint or contact surface is arranged in a cylinder space separate from the work chamber, wherein the cylinder space forms either a complete collecting chamber according to claim 2, or the collecting chamber represents only one part of the cylinder space according to claim 3.

In the first example of claim 2, wherein the collecting chamber consists essentially entirely of a closed cylinder space separated by a piston in the cylinder from the working chamber, this is a simple, exterior cylinder of a relatively narrow diameter.

In the design according to claim 3, a partial collecting chamber is connected to the flow chamber by a cylinder space which in any case forms a collecting chamber in one part. This partial collection chamber is largely freely built. It is advantageous if the partial collecting chamber is a kind of annular chamber arranged around the cylinder. From here, we get a relatively short cylinder design, but it has a correspondingly larger outer circumference. It may also be advantageous to separate the partial collecting chamber, as an external collecting chamber, from the cylinder and the single cylinder, respectively.

According to claim 5, the piston movement separating the work space from the collection chamber or from a specific part thereof is generally limited by a stop in the cylinder chamber. In this case, the stop may be located outside the cylinder space and the piston rod grip. By means of a limiter, the final pressure in the sump chamber is compressed by compressing the compressible pressure medium, in this case air or compressed air. The final pressure is chosen in such a way that the power curve of the piston of the pneumatic cylinder lies above the load curve determined by the action of the smoke outlet flap.

Furthermore, as claimed in claim 12, it is preferable to connect the working chamber, separated from the cylinder compartment, to the outside atmosphere via a pressure limiting valve located mainly in the bottom of the cylinder or in the cylinder wall. This ensures that, even when the ambient temperature rises, the final pressure in the sump chamber does not exceed the prescribed values, ensures the normal functioning of the pneumatic cylinder, and prevents the overflow of the heat exhaust flap and associated connecting elements.

As mentioned in claim 13, the pneumatic cylinder can be advantageously provided with a piston rod end lock, which allows the piston to be locked at least in the final position in the vented work chamber, thus keeping the smoke outlet open lie down. Further, according to claim 14, a double end locking of the piston rod is provided.

Claim 15 claims that the collecting chamber is pre-filled with air extracted from compressed air for the operation of the pneumatic cylinder.

The six variants of the pneumatic cylinder according to the invention with the features of the invention are further described by means of drawings with thirteen figures, in which each variant is shown in longitudinal section. Pictures show:

FIG. 1 first variant, with device for additional suction of the pressure medium and open pressure limiting valve with connection to a piston rod with a non-displayed smoke outlet;

51.2. The first variant in a position corresponding to the closed position of the smoke exhaust flap;

51.3. The second variant, with a device for additional filling of the pressure medium and a pressure relief valve, in the open position next to the smoke exhaust flap not shown;

51.4. A second variant in a position corresponding to the closed position of the smoke exhaust flap;

51.5. A third variant similar to the second variant but with a partial collecting chamber, which is designed as a ring chamber around the cylinder, in the open position of the associated smoke outlet flap;

51.6 is a third variant of FIG. 5, but in the closed position of the non-displayed smoke exhaust flap;

51.7 fourth variant, similar to the first variant but supplemented by a thermo-valve as well as an arbitrary three / two-way valve and by means of a final locking in the open position with a piston rod coupled non-displayed smoke outlet flaps;

51.8 is a cross-sectional view of the fourth embodiment according to FIG. 7;

51.9 fourth variant in the closed position position of the non-displayed smoke outlet flap, but excluding the thermo-valve and the other three / two-way valve;

FIG. 10 fifth variant in the closed position of the smoke outlet flap, with a thermal valve and finally locking of the non-displayed smoke outlet flap;

FIG. 11 is a detail in the fifth embodiment, namely the piston in position according to FIG. 10;

FIG. 12 is a detail according to FIG. 11, but in an intermediate position corresponding to the intermediate position between the closed and open position of the smoke vent not shown, and

FIG. 13 is a sixth embodiment similar to the fifth embodiment of FIG. 10, but with a special separate pressure air tank.

In FIG. 1 is generally referred to as 1 a pneumatic cylinder having a double acting piston 2 with a piston rod 3. The piston 2 separates the working chamber 4 from the chamber of the cylinder 5 in such a way that the air or compressed air, as a compressible pressure medium, forms a storage chamber.

In the cylinder chamber 5, a stop 8 is mounted centrally in the bottom of the cylinder 9.

A pressure valve 10 is inserted into the bottom of the cylinder in an unmarked flow channel 11 that connects the space of the cylinder 5 to the outside atmosphere. The pressure valve comprises in detail a spring-pressed ball pressed inward by the outside atmospheric pressure towards the cylinder space, thus opening the flow channel 11 when the pressure in the cylinder space at the piston position shown in FIG. 1 does not reach the external pressure. In this case, the cylinder space is filled with atmospheric pressure.

A pressure relief valve 12 is also inserted into the bottom of the cylinder, similar to the described pressure valve 10, but inversely directed in the flow channel 13, so that it opens towards the atmosphere when the piston is in the position shown in FIG. 2 and in the cylinder space 5, an excess pressure exceeding the value of the preset overpressure in the pressure relief valve 12.

The basic function of Fig. 1 and Fig. 2 of the presented pressure cylinder, again having in mind that the piston rod 3 is connected to the movable smoke exhaust flap by means of non-illustrated connecting elements, in the case of devices for smoke or smoke extraction. of heat, is the following:

As the open smoke outlet flap moves to the closed position at the position of the piston 2 and the piston rod 3 of FIG. 1, the working chamber 4 is supplied with compressed air through a through passage 15 through a flow channel 15, not shown by the control valve. The air pressure is exerted over the working surface of 6 pistons by moving it according to FIG. 1 so that, at the starting position shown, there is a small pressure in the space of the cylinder 5, which acts as a largely closed collecting chamber. When the piston is moved in the direction of the cylinder space 5, the pre-filled air is compressed over the compression surface 7 of the piston as it moves towards the bottom of the cylinder 9. This results in a small overpressure in the cylinder space 5, such as the pressure of the compressed air in the working chamber 4, corresponding to the ratio of the working surface 6 and the compression surface 7 and the displacement volume of the piston displaced by the piston 2 in the cylinder space 5 when it moves from one end position to FIG. 1 in the working chamber 4 in the second end position shown in FIG. When the compressed air pressure in the cylinder compartment exceeds the prescribed value, especially when the ambient temperature is raised later, the pressure relief valve 12 is opened.

In the end position shown in FIG. 2, therefore, the compressed air piston 2 forms in front of it a collecting chamber in the space of cylinder 5.

When the non-displayed smoke outlet flap needs to be opened, for example in the event of a fire, it is not necessary to supply additional energy to the pneumatic cylinder, moreover, it is sufficient to vent the working chamber via a connecting hole 14, a fitted non-displayed valve device, which may be e.g. solenoid valve or three / two way valve. In this case, then, the pressure in the working chamber 4 is practically equal to the pressure of the outside atmosphere, so that due to the pressure in the compressed air cylinder 5, the piston 2 in the end position shown in S1.2 is moved again to the other end position shown in FIG. thus opening the smoke hatch there. If the required opening angle is exceeded for the smoke exhaust flap not shown, e.g. 90 degrees, the hatch falls automatically into its final open position, e.g. 140 degrees and pull with it a piston rod 3 with a piston 2, thereby reducing the pressure in the cylinder space 5 under the pressure of the outside atmosphere, leaving the cylinder space 5 pre-filled enough for the next stage of compression when closing the smoke outlet flap. To avoid this, the described pressure valve 10 is opened to achieve the desired pre-fill rate.

The second variant shown in FIGS. 3 and FIG. 4 differs from the first variant described in that, instead of a pressure valve 10 at the bottom of the cylinder, there is a device for adding pressure medium arranged in the piston 16. In fact, there are coincident elements of the pneumatic cylinder in all described variants. similar characteristics. The details include a device for adding a pressure medium from a piston 16, in which the first slide valve 17 with a piston 19 protruding from the compression surface 18 of the piston and a spring and adjustable check valve are essential.

20. The first slide valve and non-return valve are arranged in unlabeled holes so that a flow path is created from the working chamber 4 via a preset check valve 20 and a slide valve 17 towards the cylinder space 5.

In the area of the bottom of the cylinder 21, the second variant is differently implemented in comparison with the first variant, since in the second variant, a support 22 is formed at the bottom of the cylinder 21 in the form of a piece of a hollow cylinder, such that the arm 19 of the first sliding valve 17 may not lie on the face 23 backrests 22.

The pressure limiting valve 12 is arranged here centrally along the dotted line marked along the longitudinal axis 24 of the pneumatic cylinder, extending the flow channel 13 of the pressure limiting valve 12 into the backrest 22. In this embodiment, the safety of the device is ensured by the compression surface 18 of the piston 16 reaches without stopping the front face 23 while simultaneously operating the handpiece 19.

In the position of the piston 16 shown in FIG. 3, corresponding to the open position of the non-displayed smoke outlet flap associated with the piston rod 3, the flow path is closed with a preset check valve 20 and the first slide valve 17 such that the spring first slide valve seals the flow path. For example, if operated by, for example, a three / two-way air-pressure valve on the working chamber 4, the piston 16 moves to the right in the direction of the abutment 23 and compresses pre-filled air in the cylinder space 5, corresponding to the initial pressure in the cylinder space 5, and of the ratio of the surfaces between the compression surface 18 and the unmarked piston work surface 16. The piston 16 moves to the right so that the compression surface 18 of the piston 16 rests on the front surface 23 of the abutment 22. At the same time, the handpiece 19 moves toward the spring pressure of the first slide valve 17 inside the piston 16 and the slide valve 17 opens the flow path through the piston into the cylinder space 5. If the final pressure is reached (equal comp. in the cylinder space 5 at the piston limit position 16 at the abutment 22 is still too low for some pressure differential with respect to that preset on the adjustable check valve 20, which opens until the pressure differential between the working chamber 4 and cylinder space 5 does not equate to the preset values. Such are the initial conditions for moving the piston from the position given in Fig.4 to the end position shown in Fig.3. This movement of the piston for opening the smoke outlet flap is also achieved here by venting the working chamber 4 via the connection bore 14 and the three / two-way valve not shown here. In order to achieve this final pressure in the position of the piston 16 in the cylinder space 5 according to Fig. 4, it is not necessary for the pneumatic cylinder to be connected to a non-shown flap, where the piston rod 3 is additionally pulled into a position corresponding to a completely open setting via a certain opening adjustment. Moreover, the pneumatic cylinder of Fig. 3 and Fig. 4 can be inflated without these restrictions and yet provide the required final pressure in the cylinder compartment 5.

The function of the pressure limiting valve, which guarantees the final pressure in the event of temperature changes, especially when the ambient temperature rises, is the same as in the first variant according to Figs. 1 and Fig.2.

In Fig. 5 and Fig. 6 the third variant presented differs from the second variant described above in that the collecting chamber in which the pre-filled air is compressed with the piston 16 is not entirely constructed only from the space of the cylinder 25, but also consists of an additional partial collecting chamber chamber, as a kind of ring chamber 26 arranged around a cylinder 24. There is a connection between the ring chamber 26 and the space of the cylinder 25 via at least one bore 27 in the cylinder wall 28. The collecting volume is here greater than the collecting volume for the volume of the ring chamber 26. of the cylinder space 5 in the second embodiment of FIG. 3 and S1.4 and represents cylinder space volumes 25 and 5. In other words, to achieve the same total cumulative volume, the pneumatic cylinder 24 may in this case be of a shorter design than the pneumatic cylinder 1 of FIGS. 3 and FIG.

In other respects, the functions in FIGS. 5 and FIG. 6 show the third variants as described above; the position in FIG. 5 corresponds to the position in FIG. 3 of the other variants; and the position in FIG. 6 corresponds to the position in FIG. 4 of the other variants.

In Figs. 7 to Fig. 9, the fourth variant of the pneumatic cylinder 29 responds primarily by measuring the space of the cylinder 5 in the first variant, with the stop 8 in the cylinder space, as well as after the completion of the bottom of the cylinder 9, in which the pressure valve 10 with the flow valve is arranged. channel 11, as well as a pressure relief valve 12 with a flow channel

13. In this respect, the functional description of the first variant can also be assumed in this case.

According to the present fourth embodiment, the piston 30 is connected to the piston rod 32 extending from the working surface 31. The working surface 31 restricts again the working chamber 33, which in turn is defined by the cylinder head 34.

The cylinder head 34 here has in its front outer region a generally 35 marked end lock which is suitable for locking the piston rod 32 in the position shown in FIG. 7 corresponding to the open position of the (not shown) smoke outlet flap associated with the piston rod 32. Here comprises a final locking of the locking piston 36 with a spring in the spring chamber 37, which slides on the balls 42 as locking elements for locking the piston rod 32. The locking piston 36 borders inside the cylinder head on the locking pressure space 38 which is (in FIG. 9 not shown) with a through hole 39 pressurized to the working chamber. The locking pressure chamber and the working chamber may be supplied via a further bore 40 (not shown in FIG. 9) and supplied with a pressure medium under working pressure, or vented. The pressure medium is also primarily compressed air.

On its inner face, the locking piston 36 further exhibits a section in the form of a sleeve 41, corresponding to the fact that it can cover the beads 42 when these are inserted into the annular groove 43 in the piston rod (Fig. 7) or allow the beads to move The piston rod 32 is extruded out of the annular groove and displaced radially apart into the locking pressure chamber 38 (see FIG. 9).

In detail, when the locking pressure chamber according to Fig. 7 is vented, thus also venting the working chamber 33 and the piston to the left, the smoke outlet flap is in the open position. When it engages the locking piston in the right-shifted working position, the annular groove 43 is in such a position in the sleeve section 41 that the beads 42 engage the annular groove 43 and lock the piston rod 32.

Under operating conditions of FIG. 9, where compressed air is pressurized to the pressure chamber 38 and the working chamber 33, the spring anti-lock piston is displaced to the left and the balls 42 can extend radially outwards and release the annular groove 43. In this way, the piston rod 42 is no longer locked and can be moved to the right with the piston, which corresponds to the closed position of the smoke outlet flap.

The control of the fourth variant is carried out by means of a three / two-way thermo-valve 44, which, when heated beyond the prescribed limit value, automatically vents the locking pressure chamber 38 and the working chamber 33. The thermo-valve may be further connected with an additional three / two-way valve, e.g. with manual or magnetic actuator (as solenoid valve). This three / two way valve is connected to the compressed air source.

Figure 8 shows a section through a thermo-valve 44 of the conventional embodiment, so that a detailed description is not required. This thermo-valve is connected as shown in FIG. 7 with a further bore 40. which leads to the locking pressure chamber 38.

In Figs. 10 to FIG. 12 shows the preferred heels of the pneumatic cylinder variant 45 corresponds, in this left end section, to the end latch 46 and the thermo-valve 47 in the fourth variant according to FIG. 7, and the piston area 48 is partially other variants in accordance with FIG. In general, the difference with the second variant here is a single bore 49 in the axial direction of the piston 48 and a second slide valve 50 constructed as a non-return valve 50, which further comprises the first slide valve

51. Both slide valves 50 and 51 are rubber shaped with ring shaped sealing beads 52 or. 53 on their fronts. The sealing beads 52 and 53 seal well on the flat surfaces on which they fit in the piston assembly.

The second slide valve 50 replaces the ball of the adjustable check valve 20 in FIGS. 3 and S1.4. The sealing bead 53 of the second slide valve 50 seals under the force of the spring in the figure of the unspecified pressure spring, which in roll 58 or 59 supports the second slide valve 51. or. 50, facing the annular plan face 54 of the insert 55 with a through hole 56 leading to the working chamber 57.

A handpiece 63 is actuated on the first slide valve 51 when it rests on a stop 64 in the bottom of the cylinder 65. An overpressure limiting valve 66 is mounted on the bottom of the cylinder 65, which, in connection with the working chamber 57 and substantially separate cylinder space 68 s thereof. 57. With this in mind, we can also here assume a functional description of operation as in the first variant.

A pressure limiting valve 66 is mounted on the bottom of the cylinder 65, which, in connection with the working chamber 57 and the substantially separate space of the cylinder 68, is through the bore 57. In this regard, the functional description of the first variant can also be assumed here.

The final locking 46 and the thermo-valve 47, which is connected via a bore to the locking pressure chamber 70, are described in connection with the same functioning components in the fourth embodiment. In FIG. 10 and FIG. 11 lacks the representation of the beads 42 of FIGS. 7 and FIG. 9, which work together with the bushing section 41. When the locking pressure chamber 70 and the working chamber 57 are closed by means of a three / two-way valve and a thermo-valve 47, the pressurized air pressure releases the piston rod 71 and pushes the piston 48 against the stop 64, as shown in FIG. 10. The first slide valve 51 to which the handpiece 63 operates is opened and the flow path between the work chamber 57 and the cylinder space 68 is established through the first slide valve 51 and through the second slide valve 50 which acts as a pressure differential limiter. The connection is made until a certain pressure differential is reached between the working chamber 57 and the space of the cylinder 68, which is preset on the second slide valve 50.

When the working chamber 57 and the locking chamber 70 are vented, the piston 48 moves due to the pressure in the cylinder space 68 towards the open position of the smoke outlet flap connected via the piston rod 71, with the second and first sliding valve 50, 51 sealed (see Fig. 12). In general, the second slide valve 50 has the same function as the adjustable check valve 20 for the second pneumatic cylinder variant.

Sixth, in FIG. 13 shows a variant of the pneumatic cylinder 72, which differs from the fifth variant in that it provides an external collecting chamber 73 which is connected to the bottom of the cylinder 75 by a conduit 74. It carries out a connection with the space of the cylinder 78 through the holes 76 and 77. The space of the cylinder 78 is reduced to practically zero at the shown position of the piston 48, as the piston 48 presses the working face of the bottom face of the cylinder 75 with the working surface, leaving the projecting restraint omitted. The total volume in cylinder 72 bounded by piston 48 is available here as a working chamber 79, since the outer collecting chamber 73 is spatially separated from the pneumatic cylinder 72. The working stroke of piston 48 and piston rod 80 is thus maximized.

Claims (15)

PATENT APPLICATIONS A pneumatic cylinder for actuating adjustable elements, in particular smoke exhaust flaps in smoke and heat extraction plants with double acting piston (2, 16, 30, 48) having at least one working surface (6, 31) in the cylinder (1, 24, 29, 45, 72) with at least one working chamber (4, 33, 57, 79) movable by compressed air, connected to a smoke outlet flap with a piston rod (3) and to an energy collector with an adjustable means by a control device , which by its first function acts on the work surface, the adjustable element, in particular the smoke outlet flap being driven or fixed, in particular retained in the open position, characterized in that it is provided as an energy collector by air or air. compressed air as a compressible pressure medium is filled with a collecting chamber, where the compression surface (7, 18) of the piston (2, 16, 30, 48) and its opposite work surface (6, 31) are connected to the leakage of the pressure medium and that the control device is inherently the second function is actuated by a vent valve connected to a pressure culvert by a working chamber (4, 33, 57, 79). Pneumatic cylinder according to claim 1, characterized in that the collecting chamber is entirely constructed essentially from the closed space of the cylinder (5), which is separated from the working chamber (4, 33) by the cylinder (1, 29, 45). with a piston (2, 16, 32, 48). Pneumatic cylinder according to claim 1, characterized in that the collecting chamber is in any case partly constructed from the space of the cylinder (25), which is separated from the working chamber (4) by the piston (16, 48) in the cylinder (24, 72), and that a working chamber with a flow connection (bore 27) is connected to this space of the cylinder (25). Pneumatic cylinder according to claim 3, characterized in that the partial collecting chamber, like the annular chamber (26), is arranged around the cylinder (24). A pneumatic cylinder according to claims 1 to 4, characterized in that it has a provided stop (8, 22 64) for restricting the movement of the piston in the cylinder space (5, 25, 68), which is separated from the working chamber. Pneumatic cylinder according to claim 5, characterized in that the stop (8, 22, 64) is arranged in the space of the cylinder (5, 25, 68) separated from the working chamber (4). Pneumatic cylinder according to claims 1 to 6, characterized in that the working chamber (4, 57) and the separate cylinder space (5, 25, 68) are connected via a flow connection in which a mechanically-automatically controlled pressure differential limiter is arranged . Pneumatic cylinder according to claims 6 and 7, characterized in that the first slide valve (17, 51), acting with a stop in the cylinder space and a non-return valve (20), is arranged in the piston (16, 48) as a stop. pressure differential to open the flow path in the piston (16, 48) between the cylinder space and the working chamber when the slide valve enters the stop and the pressure differential between the working chamber and the cylinder space reaches a preset value on the check valve. Pneumatic cylinder according to claim 8, characterized in that the non-return valve is designed as a second sliding valve (50) and that the second sliding valve (50) as well as the first sliding valve (51) are provided with a projecting arm (63) coaxially one after the other into one common bore (49) into which a insert (55) is inserted at one end and the first slide valve (51) and the second slide valve (50) are pressed out by means of a pressure spring arranged between them. against the sealing surface (54). Pneumatic cylinder according to claim 9, characterized in that the first slide valve (51) and the second slide valve (50) are made as a rubber mold with a ring-shaped sealing bead (52, 53) on their outer face. 11. A pneumatic cylinder, in particular so connected to the smoke outlet flap that, when opened through the design opening angle of the piston of the pneumatic cylinder, the smoke outlet flap is moved in the direction of the working chamber according to one of claims 1 to 7, characterized in that a device for supplementing the pressure medium, as a device for dosing a pressure medium in the form of an overpressure valve (10), preferably arranged in the bottom of the cylinder (9) or the cylinder wall, through which a separate space of the cylinder (5) is connected to the outside atmosphere from the working chamber (4). Pneumatic cylinder according to one of the preceding claims, characterized in that the cylinder space (5, 25, 68, 78) is separated from the working chamber (4) by a pressure limiting valve (12, 66), preferably arranged in the bottom of the cylinder (12). 9, 65, 75) or the cylinder wall connected to the outside atmosphere. Pneumatic cylinder according to one of the preceding claims, characterized in that the piston rod (32, 64, 80) is lockable by means of pressure in the sump chamber next to the vented working chamber (23, 57, 79) with at least one end latch (35). Pneumatic cylinder according to claim 13, characterized in that it has a double end piston rod lock. Pneumatic cylinder according to one of the preceding claims, characterized in that the collecting chamber is pre-filled with air.