Compressed-Gas Cartridge for Fire Protection Purposes

The present invention relates to a compressed-gas cartridge for fire protection purposes with a thermal triggering mechanism, preferably for the opening of smoke exhaust devices.

In order to open smoke exhaust flaps, skylights, or the like, preferably in roofs of large halls or auditoriums, devices have been known wherein a piston is pneumatically displaced within a servo cylinder, the piston rod of which is directly effective on the flap, door, window, or the like to be opened. The compressed air for actuating the piston is stored in a pressure bottle which is opened in case of emergency mechanically or pyrotechnically. It is also possible to connect these devices with smoke- or temperature-sensitive sensors and to trigger the opening operation automatically. Thus, small glass vessels or glass ampoules are used, which are filled with alcohol or a similar fluid and burst by expansion of the fluid when a predetermined temperature of, for example, 60.degree., 70.degree., or 80.degree. C. has been exceeded. These are, for example, so-called "ESTI" cartridges. The bursting of the vessels then causes the closing of an electric circuit via an electric switch, and this circuit, in turn, effects the opening of the pressure bottle valve. These automatically actuatable devices, however, are relatively expensive due to the electric circuit, electrically activated valve, the energy supply, etc. Also, the flawless functioning of the electrical parts of the mechanism cannot be readily checked at intervals, since the circuit is interrupted by the interposed glass ampoules.

The present invention has as an object the avoiding of the aforementioned disadvantages and the fashioning of a compressed-gas cartridge for fire protection purposes so that it is of a maximally simple construction, requires a minimum effort in assembly and operation, and furthermore is maximally insensitive to disturbances caused by the surroundings.

In accordance with the invention, there is provided a compressed-gas cartridge for fire protection purposes with a thermal triggering mechanism wherein the compressed-gas cartridge can basically be constructed as a compressed-gas bottle, filled, for example, with compressed air. The opening of this bottle is caused directly by a striker pin which penetrates, for example, a sealing diaphragm of a metal. Preferably, however, the compressed-gas cartridge is fashioned as a compressed-gas generator wherein the compressed gas is produced only in the case of emergency, so that the compressed-gas cartridge is initially, i.e. in the rest condition, not under pressure, and leakage losses during the rest condition are avoided. Such a compressed-gas generator has been described, for example, in DOS (German Unexamined Laid-Open Application) No. 1,771,644, wherein a solid propellant is ignited when required by means of a primer element mechanically triggered by the striker pin, thus producing the compressed gas. The form-fitting engagement of one end of the locking element in the striker pin during the rest condition can be accomplished, for example, by providing that the pin-shaped locking element extends into a transverse bore of the striker pin. Preferably, the striker pin, however, is equipped for this purpose with an annular groove into which the locking element extends with one end thereof, so that the striker pin rests under the bias of the tensioned spring against the locking element with the groove flank facing away from this spring. The locking element is guided in a housing so that it can flawlessly absorb the transverse force exerted thereon by the striker pin during this operation. In general, the locking element is arranged with its longitudinal axis perpendicularly to that of the striker pin, but it can also be disposed at an angle with respect to the striker pin deviating from 90.degree.. In such case, the displacement path of the locking element must, however, always be dismensioned so that it releases the striker pin during its lateral movement away from the latter, i.e. so that it comes out of engagement with the striker pin.

The locking element, in the rest condition, is supported at the abutment by way of the blocking element which is constructed as a temperature-sensitive sensor. For this purpose, the blocking element can be formed, for example, as a rod-shaped element of defined dimensions, made of a metal and/or a corresponding metal alloy which melts when a predetermined temperature has been reached, for example Wood's alloy. The temperature-dependent triggering of the compressed-gas cartridge of the present invention is then accomplished by the fact that the blocking element is partially or completely melted when the limit temperature has been exceeded, thereby changing its shape under the spring force of the locking element in such a way, or is thereby removed from its blocking position so that the locking element can move away laterally from the striker pin under the force of the biased spring associated with the locking element, such that the striker pin is released.

The compressed-gas cartridge of the present invention with the integrated thermal sensor represents a compact structural element which is of a simple structure, is insensitive, and is automatically operable, i.e. requires no additional accessories to effect, for example, the opening of smoke exhaust devices, the activation of extinguishing mechanisms, or the triggering of other temperature dependent operations.

In order to be able to also obtain, by means of the compressed-gas cartridge of the invention, an intended triggering at ambient temperatures below the predetermined limit temperatures, a further embodiment of the invention provides that the abutment of the blocking element is not constructed as a fixed member, but rather moveable as a piston displaceable under the pressure action of an electrically actuatable primer. This piston, during its displacement, likewise changes the shape of the blocking member and/or, for example, destroys this blocking member and thereby removes it out of the blocking position, so that the locking element can laterally move away from the striker pin to such an extent that the striker pin is released. This provides the possibility, for example, to intentionally trigger during a fire in the lower floors of a high rise the smoke exhaust devices located in the upper floors or in the roof, completely independently of the temperature ambient at those locations, by means of an electrical remote control arrangement. This additional selective electrical triggering can be attained with little expenditure and is advantageously combined with the thermal sensor in one component of small size. For the triggering operation, only a comparatively small amount of electrical energy is required, inasmuch as only the electrical primer element needs to be actuated, rather than an electric valve or the like of the compressed-gas cartridge. Additionally, the functional readiness of the electric triggering system can be controlled without difficulties, since there are no contacts in the circuit which are closed only by the actual triggering step. Checking can be executed in a simple manner by determining the electric resistance of the circuit, wherein the amperage of the measuring or closed-circuit current is to be selected to be so low that the electric primer elements are not initiated with certainty.

In order that the piston, in the rest condition, can serve as a solid abutment for the blocking element, it is possible to maintain the piston within the housing by way of radial shear pins or the like which are severed only after triggering of the primer element. However, it is more advantageous to provide the piston with an annular shoulder at its outer surface by means of which the piston is supported on a corresponding counter surface of the housing in the direction toward the primer charge.

A particularly favorable construction of the blocking element is accordance with the present invention is that of a glass ampoule or vessel filled with a fluid which destroys the ampoule when a predetermined temperature is exceeded. These conventional glass ampoules commercially obtainable, for example, under the name of "ESTI" cartridge, can be manufactured at low expense and react relatively quickly also in cases where the limit temperature is exceeded only by a small amount. In this connection, the constructional design of the housing receiving such ampoules must be such that the glass slivers produced during the triggering thereof do not unduly impede the lateral displacement of the locking element.

The compressed-gas cartridge of the present invention is intended particularly for the opening of smoke exhaust devices. An advantageous connection of the servo cylinders known for this purpose with the piston and piston rod, effective directly on the skylight, flap, or the like to be opened is provided in that the compressed-gas cartridge is disposed in the axial extension of the servo cylinder and is in communication with the piston chamber thereof via a reducing bore.

These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

FIG. 1 illustrates the compressed-gas cartridge with the triggering device in accordance with the present invention in a longitudinal sectional view; and

FIG. 2 illustrates the attachment of a compressed-gas cartridge system of the present invention to a skylight.

Referring now to the drawings, there is shown in FIG. 1, a compressed-gas cartridge 2, in an elevational view, inserted in a cylindrical metal cartridge case 1 of, for example, steel, brass, or aluminum, with the pyrotechnical mixture of this cartridge being ignited by a percussion-sensitive primer element 3. The cartridge is provided with a free forward volume area 4, amounting preferably to 20-50% of the cartridge volume which is disposed at the front of the compressed-gas cartridge. This volume area 4 is in communication via a reducing bore 5 with a servo cylinder 6 made, for example, of steel, and/or with the space underneath a piston 7 having a piston rod 8, both, for example, being made of aluminum. By selecting the inside cross section of the reducing bore 5, the piston speed during extension can be regulated such that the narrower the bore cross section, the lower the speed. The cartridge case 1 is arranged in the axial extension of the servo cylinder 6 and connected in a gastight manner with the latter, for example, via a threaded connection 9. The piston 7 can optionally be furthermore provided with at least one annular sealing element, now shown, contacting the inner wall of the servo cylinder 6.

At the rear end, the cartridge case 1 is connected to a striker pin housing 10, preferably by way of a screw thread 11, wherein a retaining disk 12 with a central opening 13 is clamped between the two components. The disk 12 retains, on the one hand, the primer element 3 in the recess of the compressed-gas cartridge 2 and, on the other hand, limits the axial path of the striker pin 14, shown in an elevational view. The striker pin housing 10 of preferably metal, e.g. steel, brass, or aluminum, furthermore seals the compressed-gas cartridge 2 toward the rear by means of the retaining disk 12. The striker pin 14 is guided within the cylindrical striker pin housing 10 in a recess 15 extending in the longitudinal direction of the housing. A tensioned spring 18 is disposed between a flange 16 of the striker pin and an annular shoulder 17 of the recess 15. At the rear end, the striker pin 14 has an annular groove 19 form-fittingly engaged by one end 20 of a locking element 21, shown in an elevational view. The striker pin 14 contacts, in this arrangement, the end 20 of the locking element 21 with the groove flank 22 facing away from the spring 18. During transport and assembly, the striker pin 14 is additionally retained by means of a safety locking pin 23 arranged at right angles thereto. After the installation at the smoke exhaust device or the like has been accomplished, the locking pin 23 is pulled out laterally by hand, so that the striker pin 14 is only held by the locking element 21.

The locking element 21 is disposed to be longitudinally displaced in a sensor housing 24 of, for example, steel, brass, or aluminum, which is laterally inserted, preferably threadedly inserted, in the striker pin housing 10. The longitudinal axis of the striker pin 14 and of the locking element 21 are disposed perpendicularly to each other. The other end 25 of the locking element 21 is thickened in the manner of a piston and presses under the force of the bias spring 26 against a blocking element 27 which, in turn, is in contact with the abutment 28. The abutment 28 is constructed as a moveable piston displaceable toward the locking element 21 and has an annular shoulder 29 on its outer surface. By means of the shoulder 29, the abutment 28 rests on a counter surface of the sensor housing 24 toward the side facing away from the blocking element 17. On the side of the abutment 28 facing away from the blocking element 27, a primer charge 30 is provided together with an electric primer, for example a conventional primer pellet with an incandescent wire. Ignition energy is fed to the primer charge 30 two electric leads 31. The sensor housing 24 is preferably transversely subdivided and connected by means of the screw connection 32 in the zone of the counter surface for the shoulder 29 of the abutment 28.

The blocking element 27 is constructed as an "ESTI" cartridge, extending with its neck-shaped extension 33 into a corresponding blind-hole-type recess 34 of the abutment 28. After the limit temperature for which the ESTI cartridge has been designed is exceeded, the glass ampoule is destroyed by the expansion of the fluid present therein. The glass fragments can fall out to a more or less complete extent through the lateral apertures 35 of the sensor housing 24 so that the locking element 21 can be shifted under the force of the spring 26 unimpeded in the direction toward the abutment 28, thus releasing the striker pin 14 which latter jumps toward the primer element 3 under the force of the spring 18 and, by the triggering of the primer element 3, effects the ignition of the pyrotechnical mixture of the compressed-gas cartridge.

The glass ampoule can also be selectively destroyed at temperatures below the predetermined limit temperature in an electrical manner in that primer element associated with the primer charge 30 is electrically triggered via leads 31 to cause the primer charge 30 to generate an amount of compressed gas sufficient to accelerate the abutment 28 toward the locking element 21 and thereby intentionally destroy the glass ampoule 27. The electrical primer element is preferably fashioned to be a conventional bridge primer with an internal resistance of preferably 1 to 2 ohms, actuatable by an electric current of about 0.8 ampheres and igniting, in turn, the conventional primer charge 30 producing a small amount of compressed gas, this primer charge being disposed behind the primer element. However, it is also possible to use, for example, one of the known gap or layer primer devices.

It is possible by the arrangement of the present invention, to obtain when used in a fire protection situation, an automatic triggering at a correspondingly elevated temperature, as well as to intentionally ignite, for example via smoke alarm mechanisms or manually controlled, compressed-gas cartridges which have not as yet been ignited. The electric triggering feature has the advantage that, by a so-called closed-circuit monitoring operation with a measuring current of, for instance, 10 milliamperes, the readiness of the electric parts of the system can be controlled.

FIG. 2 illustrates the connection of the compressed-gas unit 36 of the present invention having the laterally arranged sensor housing 24 with leads 31 with the servo cylinder for opening a skylight. As shown the unit 36 is disposed in the axial extension of the servo cylinder 6 having piston 7 and piston rod 8 directly effective on the skylight 38 so as to provide for opening movement about the bearing 37. The servo cylinder 6 is pivoted about the bearing 39 in the opening operation in response to activation of the compressed-gas generating unit with the position of the servo cylinder and the skylight 38 at the end of the opening operation being indicated in dashed lines. The edge of the roof bounding the skylight 38 is indicated generally by reference numeral 40. In this manner smoke exhaust openings are produced.

While we have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art, and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of appended claims.