EP0894200A1

EP0894200A1 - Pneumatic cylinder, in particular for actuating fume extraction valves in fume and heat extraction plants

Info

Publication number: EP0894200A1
Application number: EP97921772A
Authority: EP
Inventors: Andreas Grasl
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-04-29
Filing date: 1997-04-25
Publication date: 1999-02-03
Anticipated expiration: 2017-04-25
Also published as: PL183929B1; EP0894200B1; JP4026855B2; DE59707600D1; JP2001511233A; ATE219820T1; WO1997041357A1; SI9720033A; CZ296160B6; PL329729A1; CZ345498A3; DE19617058A1

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

Compressed air cylinders, in particular for actuating smoke flaps in smoke and heat exhaust systems

The invention relates to a compressed air cylinder, in particular for actuating smoke flaps in smoke and heat extraction systems according to the preamble of claim 1.

Compressed air containers with a piston which can be acted on from both sides and have at least one working surface, which can be displaced by compressed air in a cylinder with at least one working chamber, are used, for example, in smoke and heat exhaust ventilation systems (abbreviated: RWA systems) in order to prevent fire automatically or remotely open the smoke and heat exhaust flaps by applying compressed air to a cylinder chamber or a cylinder chamber so that smoke can be drawn off, which would otherwise make rescue difficult or impossible, and thus create a central access for the rescue. In addition, the formation of accumulation heat is to be prevented by opening the heat and smoke exhaust flaps. The printing cylinders used must meet high safety requirements. In this context, it is also known to provide compressed air cylinders with end position locks, which, inter alia, are intended to ensure extensive security against break-ins. A particularly advantageous end position lock, which is also suitable for locking an intermediate position of a piston rod of the compressed air cylinder, is characterized in that an additional locking rod is provided coaxially to the piston rod and displaceable relative to it up to a stop on the piston rod. which delimits a partial stroke of the piston rod and, in this partial stroke position, projects into an outer locking cylinder arranged on a locking piston (EP 0 363 575 B1). An additional locking piston is displaceable in the locking cylinder, which surrounds balls with a sleeve-like section in the partial stroke position, which engage in an annular groove in the additional locking rod and are otherwise radially movable. The radially outward moving Balls are released when the sleeve-like section has moved axially away. The additional locking piston is connected to the next adjacent cylinder chamber via a pressure-controlled reversing valve when a predetermined pressure is exceeded. This locking of an intermediate position is combined with locking elements of the end position locks designed as balls, which are held in grooves of the piston rod via spring-loaded locking pistons.

One of the above-mentioned safety requirements of the compressed air cylinders used is that, in the event of a fire, they open the smoke flaps coupled to them practically fail-safe and hold them in the open position, for which purpose one of the end position locks mentioned can be used. To ensure that the smoke flap can be opened reliably even in the event of a fire, the pressure-carrying medium is fed via fire-protected lines in the case of pressure-operated RWA cylinders. However, the use and installation of fire-protected cables represents a considerable additional effort.

Another known possibility of fire-protected design of an SHEV system constructed with an SHE cylinder is that the SHE cylinder is equipped with a gas pressure spring. However, apart from the effort required for this, this gas pressure spring may not yet be reliable enough.

Furthermore, it is known to connect the RWA cylinder to a mechanical spring which stores so much spring energy that a smoke flap can be pivoted into its open position together with the moving parts of the RWA cylinder in the event of a fire. As a result of this additional spring, however, the RWA cylinder equipped with it is voluminous, particularly bulky in length.

The object of the present invention is therefore to provide a compressed air cylinder which is as compact as possible and which is initially called type as RWA cylinder to create, which manages without additional auxiliary energy (type) and without additional external, especially fire-proof lines, and which is easy to install, especially in RWA systems.

This object is achieved by the formation of a compressed air cylinder of the type mentioned at the outset with the features specified in the characterizing part of claim 1.

This compressed air cylinder does not require any additional type of auxiliary energy, since it is only controlled by the compressible pressure medium available for its normal operation, ie in particular compressed air. When this compressed air cylinder is actuated normally, in particular to close a smoke flap, closed air is automatically compressed in the storage chamber of the compressed air cylinder, which thus forms an air spring in connection with the piston. To open a smoke flap, in particular in the event of a fire, only the pressure prevailing on the working side of the piston needs to be reduced by venting the working chamber in order to move the piston under the action of the compressed air in the storage chamber in such a way that the smoke flap opens ¬ net. This mode of operation therefore presupposes that the storage chamber, which adjoins the compression side of the piston facing away from the working surface, is sufficiently pre-filled with air before the piston compresses the compressible air in the storage chamber sufficiently when pressure is exerted on its working surface can. The pressure built up in the storage chamber depends on the ratio of the working surface of the piston to its compression surface, the working surface being in particular smaller, and on the stroke of the piston or its displacement volume when it moves from a first to a second end position. This function presupposes that at least in the case of constant ambient conditions (temperature), in particular during the subsequent stroke movements, as little air loss as possible occurs in the storage chamber. In the case in which the compressed air cylinder is used in an RWA system, in which the flue gas flap extends beyond a predetermined opening angle, usually 90 °, under the influence of its gravity into a larger opening angle of, for example, 140 ° pivots and thereby inevitably entrains the piston rod of the compressed air cylinder via the usual mechanical connecting elements, air is sucked into the feeder chambers, whereby a preceding loss of pressure medium can be at least partially compensated for. A suitable constructive measure to specifically use this suction effect in the latter specific SHEV systems with a large opening angle is specified in claim 11.

Accordingly, the pressure medium refill device, in particular for the above-mentioned special SHEV systems, has a simple design in that it is designed as a pressure medium suction device in the form of a vacuum valve, preferably in a cylinder base or a cylinder wall, via which the cylinder space separated from the working chamber with the Outside atmosphere communicates. Via this vacuum valve, the filling of the storage chamber can be specifically maintained by sucking in air from the outside atmosphere, using the normal function of the compressed air cylinder. With this design of the compressed air cylinder, a compact design can also be achieved.

Alternatively, as a pressure refill device, the working chamber and the cylinder space divided by it can be connected via a flow path in which a mechanically automatically controlled differential pressure limiter is arranged. In this case, in a position of the piston of maximum compression of the compressed air contained in the storage chamber, which is preferably predetermined by a stop, the path to the working chamber is opened when the pressure difference between the working chamber and the storage chamber exceeds a value preset on the differential pressure limiter. there partial pressure equalization occurs, with which the pressure medium lost due to possible leakage is automatically replenished in the storage chamber.

In particular, this variant of the pressure refilling device is advantageously compact in the piston according to claim 8: a first valve spool and a check valve as differential pressure limiter are arranged in the piston in the piston such that a flow path in the piston between the working chamber and the partitioned by him can be opened. For this purpose, the first valve slide can be actuated by a tappet arranged in the cylinder space that forms the storage chamber. The flow path in the piston is opened when the piston strikes the first valve slide, in particular its tappet, against the stop or a corresponding solid surface and a pressure difference between the working chamber and the cylinder space exceeds a value preset on the check valve.

A preferred variant of the compressed air cylinder has the features that the check valve is designed as a second valve spool and that the second valve spool and the first valve spool with a plunger projecting therefrom are mounted coaxially one behind the other in a common bore in the piston, in one end of which an insert is inserted and that the first valve spool and the second valve spool are pressed outwards against sealing surfaces by a pressure spring arranged between them. This variant can be produced with only a few parts in a way that is favorable to manufacture, in particular with regard to the design of the piston with only one bore for both valve spools.

Particularly good seals with maximum storage capacity can be achieved by using the first valve spool and the second valve spool as molded rubber parts with side are formed ring-shaped sealing bead.

The function of the first valve slide arranged in the piston presupposes that a stop or a corresponding fixed surface limits the piston movement. This stop or the surface is arranged in the cylinder space separated from the working chamber, this cylinder space either completely forming the storage chamber, see claim 2, or can form part of this storage chamber, see claim 3.

In the former case according to claim 2, in which the storage chamber is completely formed by an essentially closed cylinder space, which is divided in the cylinder from the working chamber by the piston, it is an extremely uncomplicated construction of relatively narrow diameter .

In the embodiment according to claim 3, in which a partial storage chamber communicates with the cylinder space, which at most forms part of the storage chamber, via a flow path, the partial storage chamber can be designed largely freely. The partial storage chamber is advantageously an annular chamber which is arranged around the cylinder. This results in a relatively short construction of the cylinder, which, however, has a relatively large outer circumference. It can also be advantageous to constructively separate the partial storage chamber from the cylinder or the cylinder unit as an external storage chamber.

According to claim 5, the displaceability of the piston is generally limited by a stop in the cylinder chambers, which is separated from the working space and forms a storage chamber or a part thereof. In this case, the stop can also be arranged outside the cylinder space and, for example, engage a piston rod. By the stop, the final pressure in the storage chamber is compressed by the compressible pressure medium, here air or compressed air. The final pressure is chosen so high that the force-stroke curve of the compressed air cylinder is always above the load curve which is determined by the actuation of the smoke vent flap.

Furthermore, according to claim 12, the cylinder chamber separated from the working chamber is preferably connected to the outside atmosphere via an overpressure relief valve preferably arranged in a cylinder bottom or a cylinder wall.

10 This ensures that, even when the ambient temperature rises, the final pressure in the storage chamber does not exceed a predetermined value in order to ensure normal functioning of the compressed air cylinder and overstressing the heat exhaust flap and the connections connected to it

15 elements to avoid.

As mentioned, the compressed air cylinder can advantageously be equipped with an end position locking device which engages the piston rod, through which the piston at least

20 can be locked in one end position when the working chamber is vented in order to keep the smoke flap open. In a development according to claim 14, a locking of the piston rod on both sides is provided.

25

In claim 15 it is emphasized that the memory chamber is prefilled with air, which can also be branched off from the compressed air for actuating the compressed air cylinder.

Six variants of the air cylinder according to the invention with

30 inventive features are described below with reference to a drawing with thirteen figures, in which each variant is shown in a longitudinal section. Show it:

1 shows a first variant with a pressure medium suction

35. device and a pressure relief valve in an open position with a piston rod related smoke flap, not shown; 2 shows the first variant in a position which corresponds to a closed position of the smoke flap;

3 shows a second variant with pressure medium refilling device and pressure relief valve in a position which corresponds to an open position of the smoke extraction flap (not shown);

10

4 shows the second variant in a position which corresponds to the closed position of the smoke flap;

15

5 shows a third variant similar to the second variant, but with a partial storage chamber, which is arranged as an annular chamber around the cylinder, in a position assigned to the open position of the smoke flap (not shown);

6 shows the third variant according to FIG. 5, but in a position which is assigned to the closed position of the smoke vent flap;

25

Fig. 7 shows a fourth variant similar to the first variant supplemented with a thermal valve and any three / two-way valve and one

End position locking in an open position of the smoke extraction flap, not shown, connected to a piston rod;

8 shows a cross section through the fourth variant according to FIG. 7;

35. . . . . .

9 shows the fourth variant in a position which corresponds to a closed position of the smoke flap. speaks, but without thermal valve and other three / two-way valve;

10 shows a fifth variant in a position that corresponds to a closed position of the smoke extraction flap, with a thermal valve and an end position lock of a smoke extraction flap, not shown;

11 shows a detail of the fifth variant, namely the piston in a position according to FIG. 10;

FIG. 12 shows the detail according to FIG. Li, but in an intermediate position between the positions, which corresponds to a closed or open position of the smoke flap, and

13 shows a sixth variant similar to the fifth variant according to FIG. 10, but with a separate compressed air reservoir.

In FIG. 1, a compressed air cylinder is generally designated 1, which has a piston 2 with a piston rod 3 that can be acted upon on both sides. The piston 2 separates a working chamber 4 from a cylinder chamber 5, which is designed as a storage chamber storing air or compressed air as a compressible pressure medium. A stop 8 is mounted centrally on a cylinder base 9 in the cylinder chamber 5.

A vacuum valve 10 is embedded in the cylinder bottom, specifically in a flow channel 11 connecting the cylinder chamber 5 with an external atmosphere (not specified). The vacuum valve comprises in particular a spring-loaded ball which is pressed inwards to the cylinder chamber by the external atmospheric pressure is and opens the flow channel 11 when the pressure in the cylinder space falls below the external pressure in the position of the piston shown in Fig. 1 by a predetermined value. In this case, air is replenished into the cylinder space under atmospheric pressure. The overpressure limiting valve 12, likewise recessed in the cylinder base, is constructed similarly to the described vacuum valve 10, but in reverse is oriented in a flow channel 13, so that it opens it to the outside atmosphere when the piston 2 is shown in FIG. 2 Position and in this case there is an overpressure in the cylinder space 5 which exceeds a value preset on the overpressure limiting valve 12.

The basic function of the shown in FIGS. 1 and 2

The 10th compressed air cylinder 1 is as follows, it again being assumed that the piston rod 3 is connected to a pivotable smoke flap in an RWA system via connecting elements (not shown):

15

In order to move the trigger flap open in the position of the piston 2 and the piston rod 3 according to FIG. 1 into a closed position, the working chamber 4 is supplied with compressed air via a connection bore 14 and a flow channel 15 by means not shown, in particular controlled valves provided.

The compressed air acts on the piston via a working surface 6, which is shifted to the right in FIG. 1, since in the starting position shown there is a low pressure in the cylinder space 5 as a largely closed storage chamber. When moving the piston towards the

25 cylinder space 5, the air pre-filled in it is compressed by the compression surface 7 of the piston, which thus moves towards the cylinder bottom 9. This creates a lower overpressure in the cylinder space 5 than the pressure of the compressed air in the working chamber 4, corresponding to the ratio of the

30 work surface 6 to the compression surface 7 and the piston displacement volume, which displaces the piston 2 in the cylinder space 5 when it moves from the end position shown in FIG. 1 to the end position shown in FIG. 2 under the action of the pressure of the compressed air in the working chamber 4 is moved.

35th _W hen the pressure of the thus compressed air in the cylinder space a predetermined value particularly in späterer- Erhö¬ _h _d ung he ambient temperature exceeds the pressure relief valve opens Über¬ 12th

In the end position shown in FIG. 2, the piston 5 is thus biased under the pressure of the compressible air in the cylinder space 5 as a storage space.

If the smoke flap, not shown, for example

10 is to be opened in the event of a fire, it is not necessary for the compressed air cylinder to be supplied with additional energy, rather it is sufficient to vent the work space through a valve arrangement (not shown) which is connected to the connection bore 5 and which can be, for example, a solenoid valve or

15 three / two-way valves. In this case, the pressure in the working chamber 4 is practically equal to the pressure of the outside atmosphere, so that under the pressure of the air biased in the cylinder space 5, the piston 2 returns from the end position shown in FIG. 2 to the position shown in FIG 1 end position shown forward

20 can move and the smoke flap can open. If a predetermined opening angle of, for example, 90 ° is exceeded when the smoke flaps roll over, the flap automatically drops into its open end position of, for example, 140 ° and pulls the piston rod 3 with the piston 2 along with it,

25 whereby the pressure in the cylinder space 5 can drop below the pressure of the outside atmosphere, but which means that the cylinder space 5 would no longer be sufficiently pre-filled for the next compression phase when the smoke flap is closed. In order to avoid this, the vacuum valve 10 opens as described until

30 the desired degree of filling has been reached.

The second variant shown in FIGS. 3 and 4 differs from the first variant discussed in that instead of the vacuum valve 10 in the cylinder bottom there is a pressure

35. middle refill device is arranged in the piston 16. Incidentally, bear in all variants of the air cylinder matching elements have the same reference numerals. In particular, the pressure medium refill device in the piston 16 essentially consists of a first valve slide 17 with a plunger 19 protruding from a compression surface 18 of the piston and a spring-loaded and thus presettable check valve 20. The first valve slide and the check valve are arranged in bores which are not designated , which form a flow path from the working chamber 4 via the pre-adjustable check valve 20 and the valve slide 17 to the cylinder chamber 5.

In the area of its cylinder base 21, the second variant is also designed differently than the first variant, in which, in the second variant, a stop 22 in the form of a hollow cylinder is formed in one piece with the cylinder base 21, in such a way that the plunger 19 of the first Valve spool 17 can encounter an end face 23 of the stop.

The pressure relief valve 12 is here arranged centrally to the longitudinal axis 24 of the compressed air cylinder, indicated by a dash-dotted line, the flow channel 13 of the pressure relief valve 12 reaching into the interior of the stop 22. With this construction, a secure contact of the compression surface 18 of the piston 16 with the end face 23 of the stop is achieved without the piston tilting and the plunger 19 being actuated at the same time.

In the position of the piston 16 shown in FIG. 3, which is assigned to an open position of the smoke flap which is connected to the piston rod 3, the flow path via the presettable check valve 20 and the first valve slide 17 is closed because the spring-loaded valve first valve slide seals the cylinder chamber 5 with respect to the flow path. If, for example, three / two-way valves are used to apply compressed air to the working chamber 5, the piston 16 again moves to the right in the direction of the valve under compression of the air pre-filled in the cylinder chamber 5. impact 23, corresponding to the initial pressure prevailing in the cylinder space 5 and the area ratio between the compression surface 18 and the unspecified working surface of the piston 16, namely until the compression surface 18 of the piston 16 abuts the end face 23 of the stop 22, at the same time the plunger 19 is pushed inward against the spring loading of the first valve spool 17 into the piston 16 and the valve spool 17 opens the flow path in the piston to the cylinder space 5. If the final pressure prevailing in the cylinder space 5 (equal to the compression pressure) in the stop position of the piston 16 at the stop 22 is still too low by a differential pressure which is set on that on the presettable check valve 20, the check valve opens until the differential pressure between the working chamber 4 and the cylinder chamber 5 reaches the preset value. The same initial conditions for a movement of the piston from the end position shown in FIG. 4 to the end position shown in FIG. 3 are therefore always present. This movement of the piston to open the smoke flap also takes place here when the working chamber 4 is vented via the connection bore 14 and the three / two-way valves, not shown. To achieve this final pressure in the position according to FIG. 4 of the piston 16 in the cylinder space 5, it is not necessary for the compressed air cylinder to be connected to a flap which flaps the piston rod 3 into a further open position pulls, which corresponds to the fully open position, rather the compressed air cylinder according to FIGS. 3 and 4 can be used without this restriction and nevertheless ensures a predetermined final pressure in the cylinder space 5.

The function of the pressure relief valve, which guarantees the final pressure even in the event of temperature changes, in particular temperature increases in the environment, is the same as in the first variant according to FIGS. 1 and 2. The third variant shown in FIGS. 5 and 6 differs from the second variant discussed above in that the storage chamber, in which the pre-filled air is compressed by the piston 16, is not completely formed by a cylinder space 25. but that in addition a partial storage chamber is arranged as an annular chamber 26 around the cylinder 24. The annular chamber 26 is connected to the cylinder space 25 via at least one bore 27 in a cylinder wall 28. The storage volume is thus larger than the storage volume by the volume of the annular chamber 26

10 of the cylinder space 5 in the second variant according to FIGS. 3 and 4, the same volumes of the cylinder spaces 25 and 5 are assumed. In other words, if the same total storage volume is to be achieved, the compressed air cylinder 24 can be short

15 are built as the compressed air cylinder 1 in FIGS. 3 and 4.

The functions of the third variant shown in FIGS. 5 and 6 are otherwise, the position in FIG. 5 corresponding to the position in FIG. 3 and the position

20 tion in Fig. 6 the position in Fig. 4 of the second variant, the same as discussed above.

The fourth variant of the compressed air cylinder 29 shown in FIGS. 7 to 9 corresponds primarily in the area of the

25 cylinder chamber 5 of the first variant with the stop 8 in the cylinder chamber and the closing cylinder bottom 9, in which a vacuum valve 10 with a flow channel 11 and a pressure relief valve 12 with a flow channel 13 are arranged. In this respect, with regard to the functional

30 the first variant.

According to the present fourth variant, a piston 30 is connected to a piston rod 32 which protrudes from a working surface 31 of the piston. The work surface 31 is limited again

35. around a working chamber 33, which on the other hand is defined by a cylinder head 34. The cylinder head 34 here receives in its front outer area a generally designated 35 end position lock, which is suitable for the piston rod 32 in the position shown in FIG. 7, the open position of a smoke extraction flap connected to the piston rod 32 (not shown) ) corresponds to lock. For this purpose, the end position locking comprises a locking piston 36, the springs in the spring chamber 37 in the drawing to the right in the direction of balls 42 as locking elements.

10 The locking piston 36 delimits a locking pressure chamber 38 in the interior of the cylinder head, which is in a pressure-conducting connection with the working chamber via a through bore 39 (not shown in FIG. 9). The bolt pressure chamber and the working chamber can be opened via further holes 40 - which are shown in

15 9 are also not shown - are supplied via valves with the pressure medium under working pressure or are vented. Here too, the pressure medium is preferably compressed air.

20 On an inner end face, the locking piston 36 further has a sleeve-like section 41, which is suitable for covering the balls 42 when the balls are in an annular groove 43 in the piston rod, see FIG. 7, or to release them, so that the Balls by moving the piston

25 rod 32 can be pressed out of the annular groove 43 and moved radially outward into the bolt pressure chamber 38, see FIG. 9.

Specifically, when the bolt pressure chamber in FIG. 7 is vented, which also means that the working chamber 33 is vented and the

30 piston is pushed to the left into the position opening the smoke flap, the annular groove 43 assumes a position under the sleeve-shaped section 41 of the locking piston pushed to the right in this operating case, as a result of which the balls 42 are retained in the annular groove 43 and the

35. Lock the piston rod 32. In the operating case according to FIG. 9, in which compressed air has flowed into the bolt pressure chamber 38 and the working chamber 33 under working pressure, on the other hand the locking piston is pushed to the left against the spring force and the balls 42 can retract radially outwards and the release the annular groove 43, whereby the piston rod 42 is no longer locked and can be taken to the right by the piston, which corresponds to the closed position of the smoke flap.

Variant 4 is controlled by a three / two-way thermostatic valve 44, which automatically ventilates the bolt pressure chamber 38 and the working chamber 33 when heated above a predetermined limit value. The thermal valve can be connected to a further three / two-way valve 45, which can be of any size, e.g. can be operated manually or magnetically (as a solenoid valve). This three / two-way valve is connected to a compressed air source.

8 shows a section through the thermal valve 44 of conventional construction, which therefore does not need to be described in detail. This thermal valve is, as also indicated in FIG. 7, connected to further bores 40 which lead to the locking pressure chamber 38.

The preferred fifth variant of the compressed air cylinder 45 shown in FIGS. 10 to 12 corresponds in its left end section with an end position lock 46 and a thermal valve 47 to the fourth variant according to FIG. 7 and in the area of the piston 48 partially to the second variant According to FIG. 4, essentially different from the second variant, a second valve slide 50, which forms the check valve 50, and a first valve slide 51 are arranged in a single bore 49 in the axial direction of the piston 48. Both valve slides 50, 51 are designed in the form of a molded rubber part with an annular sealing bead 52 and 53 on the end face thereof. The sealing bead 52, 53 seals well in connection with a flat surface, where he comes to the plant.

The second valve spool 50 replaces the ball of the pre-adjustable check valve 20 in FIGS. 3 and 4. The sealing bead 53 of the second valve spool 50 seals under spring force a pressure spring, not shown in the drawing, which is attached to a collar 58 or 59 supports the first or second valve slide 51 or 50, against an annular flat end face 54 of an insert 55 with a passage

10 bore 56 from which leads to a working chamber 57.

The first valve slide 51 is actuated by a plunger 63 when the plunger abuts a stop 64 on a cylinder bottom 65.

15

The cylinder base 65 has an overpressure limiting valve 66 which is connected via a bore 57 to a cylinder space 68 which is essentially separate from the working chamber 57. For its function, reference can again be made to the first variant.

20th

The end position lock 46 and the thermo valve 47, which is connected to a bolt pressure chamber 70 via a bore, were used in conjunction with the equivalent components

25 elements of the fourth variant discussed. 10 and 11, representations of the balls 42 in FIGS. 7 and 9, which cooperate with a sleeve-shaped section 41, are missing. If the bolt pressure chamber 70 and the working chamber 57 are pressurized with compressed air under working pressure via a three-way valve to which the thermo valve 47 is connected, the

30 piston rod 71 unlocked, and the piston 48 is pressed, as shown in Fig. 10, the stop 64. As a result, the first valve slide 51 actuated via the tappet 63 opens, and a flow path becomes via the first valve slide 51 and the second valve acting as a differential pressure limiter

35. slide 50 in the piston 48 between the working chamber 57 and the cylinder chamber 68 opened until a differential pressure between the working chamber 57 and the cylinder chamber 68 reaches a value preset on the second valve slide 50.

When the working chamber 57 and the locking pressure chamber 70 are vented, the piston 48 is pushed to the left by the pressure prevailing in the cylinder space 68 to open the smoke extraction flap connected to the piston rod 71, the second and the first valve slide 50, 51 sealing, see FIG 12. Otherwise, the second valve slide 50 has the same function as the adjustable check valve 20 of the second variant.

The sixth variant of the compressed air cylinder 72 shown in FIG. 13 differs from the fifth variant essentially in that an external storage chamber 73 is provided which is connected to the cylinder base 75 via a line 74. In it it is connected via bores 76, 77 to a cylinder chamber 78, the volume of which in the position of the piston 48 shown is reduced to practically zero, because the piston 48 is pressed with a working surface onto a corresponding end face of the cylinder base 75 and one of the latter outstanding stop is missing. The entire volume delimited by the cylinder 48 in the cylinder 72 is thus available as the working chamber 79, while the external storage chamber 73 can be accommodated spatially separate from the compressed air cylinder 72. The working stroke of the piston 48 and the piston rod 89 are maximized.

Claims

1 claims:

Compressed air cylinder, in particular for actuating smoke flaps in smoke and heat exhaust systems, with a piston (2, 16, 30, 48) which can be acted on from both sides and has at least one working surface (6, 31) which is in a cylinder (1, 24, 29, 45, 72) with at least one working chamber (4, 33, 57, 79) is displaceable by compressed air, and with an energy store with adjusting means,

10 which, controlled by a control device, open or keep the smoke flap open, so that an air or compressed air as a compressible pressure medium storage chamber is used as the energy store

15 is provided, which is connected to a compression surface (7, 18) of the piston (2, 16, 30, 48) on its side facing away from the working surface (6, 31) in a pressure-medium-conducting connection, and that the control device connects to the working chamber (4, 33, 57, 79) in a pressure-conducting connection

20 The venting valve is actuated.

2. Compressed air cylinder according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the storage chamber is completely formed by a substantially closed cylinder space (5), the

25 in the cylinder (1, 29, 45) from the working chamber (4, 33) by the piston (2, 16, 32, 48) is divided.

3. Air cylinder according to claim 1, d a d u r c h g e k e n n z e i c h n e t,

30 that the storage chamber is at most partially formed by the cylinder space (25) which is divided in the cylinder (24, 72) from the working chamber (4) by the piston (16, 48), and that with this cylinder space (25) a partial storage chamber via a flow path (bore 27)

35. communicates.

.. compressed air cylinder according to claim 3, characterized in that as a partial storage chamber, an annular chamber (26) around the

Cylinder (24) is arranged.

i. Compressed air cylinder according to one of claims 1 - 4, so that a stop (8, 22, 64) is provided which limits the displaceability of the piston into the cylinder space (5, 25, 68) which is divided off from the working chamber.

Compressed air cylinder according to claim 5, d a d u r c h g e k e n n z e i c h n e t that the stop (8, 22, 64) on that of the working chamber

(4) divided cylinder space (5, 25, 68) is arranged.

Compressed air cylinder according to one of claims 1-6, characterized in that the working chamber (4, 57) and the cylinder space (5, 25, 68) divided by it are connected via a flow path in which a mechanically automatically controlled differential pressure limiter is arranged.

Compressed air cylinder according to claims 6 and 7, characterized in that in the piston (16, 48) a first valve slide (17, 51) which can be actuated by the stop in the cylinder space and a check valve (20) are arranged as a differential pressure limiter such that a Flow path in the piston (16, 48) between the cylinder chamber and the working chamber is opened when the valve slide abuts the stop and a differential pressure between the working chamber and the cylinder chamber reaches a value preset on the check valve.

Compressed air cylinder according to claim 8, characterized in that the check valve is designed as a second valve slide (50) and that the second valve slide (50) and the first valve slide (51) with a plunger (63) projecting therefrom coaxially one behind the other in a common bore (49) in the piston (48) are mounted, in one end of which an insert (55) is inserted, and that the first valve slide (51) and the second valve slide (50) are pressed outwards against sealing surfaces (54) by a compression spring arranged between them.

10. Compressed air cylinder according to claim 9, so that the first valve spool (51) and the second valve spool (50) are formed as molded rubber parts with ring-shaped sealing beads (52, 53) on their outer end face.

11. Compressed air cylinder, which is in particular connected to a smoke flap in such a way that when it is opened, the piston of the compressed air cylinder is moved in the direction of the working chamber through the smoke flap over a structurally predetermined opening angle, according to one of claims 1 - 7, characterized in that the pressure medium refilling device is designed as a pressure medium suction device in the form of a pressure relief valve (10), preferably in a cylinder base (9) or a cylinder wall, via which the cylinder chamber (5), which is separated from the working chamber (4), with the Au ¬ external atmosphere is related.

12. Compressed air cylinder according to one of the preceding claims, characterized in that the cylinder chamber (5, 25, 68, 78) divided off from the working chamber (4) via a preferably arranged in a cylinder bottom (9, 65, 75) or a cylinder wall Overpressure limiting valve (12, 66) is connected to the outside atmosphere.

13. Compressed air cylinder according to one of the preceding claims, characterized in that a piston rod (32, 64, 80) with at least one end position lock (35) can be locked in the position moved out by the pressure in the storage chamber when the working chamber (33, 57, 79) is vented .

14. Compressed air cylinder according to claim 13, characterized by a bilateral end position locking of the piston rod.

15. Compressed air cylinder according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the storage chamber is pre-filled with air.