GB2359487A

GB2359487A - Fire extinguishing or security device

Info

Publication number: GB2359487A
Application number: GB0004458A
Authority: GB
Inventors: Phillip Raymond Michael Denne
Original assignee: TOMMOROWS DESIGN Co Ltd
Current assignee: TOMMOROWS DESIGN Co Ltd
Priority date: 2000-02-26
Filing date: 2000-02-26
Publication date: 2001-08-29
Also published as: EP1259297A1; KR20030025906A; AU3392101A; IL151470A0; GB0004458D0; IL151470A; WO2001062344A1; JP2003525668A

Abstract

The device comprises a vessel having a plurality of sealed orifices disposed over its surface and actuable means for generating pressure in the vessel to cause a fluid therein to break the seals on the orifices and be expelled from the vessel in an atomised form. The orifices may be sealed by individual plugs or by a continuous membrane deposited on the vessel inner or outer surface. Pressure may be generated using a cartridge containing a gas generating material. Utility is in fire extinguishing or the vessel can contain a dye as the fluid to mark an intruder.

Description

1 2359487 1 FIRE EXTINGUISHING APPARATUS is the The present invention

relates to f ire extinguishers of the type.in which a volume of extinguishant is contained in a sealed vessel from which it is released when required.

In existing f ire extinguishant is contained in order of 10 extinguishers is leaks from the extinguishers of the above type, the ejected by means of an inert gas which the vessel at considerable pressure of bar. A disadvantage of known such that, inevitably, the pressurising gas vessel and regular inspection and maintenance is required to ensure that the fire extinguishers will be effective when required. Another feature of such extinguishers is that they have a single nozzle, with or without a surrounding horn, so that.the extinguishant issues as a directed jet. In some circumstances this is satisfactory, for example if a fire has a well defined seat or origin, but there are circumstances where a more disperse mist or fog of extinguishant would be more effective both to cool an extended region of fire below the ignition point of the material concerned and to exclude oxygen from the fire zone. Conventional self-contained fire extinguishers do not provide this facility.

A fire extinguisher is known in which a fire 2 extinguishing liquid is contained in asealed vessel which has a chemically activated gas-generating cartridge at one end and an atomising nozzle at the other end of the vessel. The atomising nozzle is sealed by a membrane between it and the body of the vessel. The membrane is ruptured when the gas generating cartridge is activated in response to the detection of a fire. The extinguishing liquid is then ejected through the nozzle in the form of a mist or fog. Such a device can be used in the manner of a conventional hand operated fire extinguisher, or it can be incorporated into the structure of a building together with other such extinguishers to provide an overall region of coverage in the manner of a conventional sprinkler system, although each extinguishers in fact operates independently The present invention thus seeks to provide an improved self-contained fire extinguisher or security devi.ce which is not subject to the loss over time of pressure in a propellant for a liquid medium contained in the extinguisher and which is capable, when activated, of expelling this medium in the form of a substantially uniformly distributed mist or fog.

According. to the present invention there is provided apparatus capable of acting as a fire extingui sher and/or a security device comprising a vessel having a plurality of sealed orifices disposed over its surface and means 3 for generating in the vessel in response to an actuator impulse a pressure sufficient to cause a fluid contained in the vessel to overcome the orifice seals and to be expelled through the orifices in an atomised state.

The preferred form of the vessel is spherical, but other pressureresistant shapes can be used, for example, the vessel can be in the form of a cylinder with domed ends, or it can be hemispherical. The latter shape has the advantage that the vessel can be mounted directly upon a ceiling or wall of a building. On the other hand a spherical or cylindrical vessel has the advantage that it can be rolled towards a fire.

The orifices in the vessel can be sealed by a continuos membrane deposited on either the inner or the outer surface of the vessel, by individual membrane over each orifice, or by an expellable plug in each of the orifices.

The means for generating pressure within the vessel may comprise a cartridge containing a gas-generating material or materials, and means for initiating a gas-producing reaction on the material or materials. Alternatively, the pressure and gas can be contained in an hermetically sealed cartridge a portion of the envelope of which is ruptured to allow the pressurising gas to pass into the vessel.

4 In order to. prevent the rupturing of the vessel it is important that the pressurising gas either is produced in the form of a controlled burn rather than explosively, or is introduced into the vessel in a controlled manner. Preferably the pressuring gas is introduced initially into an enclosure in the vessel which forms a dead space in which any initial shock waves can be dissipated before the pressuring gas acts upon the liquid within the vessel. Preferably the material forming the enclosure is capable of expanding like a balloon to fill the vessel, so squeezing the liquid out and preventing the preferable venting of the pressurising gas through the orifices in the vessel nearest to the point in which the pressurising gas is produced.

In the case where the pressurising gas is produced by means of a chemical reaction the reaction may be produced by an electrically induced ignition of a suitable material, or if more than one reactant is involved, by the rupture of a membrane separating the reactants. The gas generating means may be such as to respond directly to a fire detection signal, the heat of a fire, or by the manual operation of a trigger device. Alternatively, a group of fire extinguishers can be connected into an extended system with centralised, or local, c ontrol.

As in the earlier fire extinguisher discussed hereinbefore the liquid in the vessel may contain a dye to indicate.that an extinguisher has been discharged.

The addition of the dye also facilitates the use of the extinguisher in a second role as a security device.

The invention will now be described by way of example with reference to the attached drawing which is a schematic cross-sectional view of an embodiment of the invention.

Referring to the drawing, a self-contained fire extinguisher consists of a spherical vessel 1 which contains an extinguishant liquid usually water 2. The spherical vessel 1 has an array of atomising orifices 3 distributed regularly over its surface. The orifices 3 are sealed by a membrane 4 which covers the outside of the vessel 1. At the top of the vessel 1, as drawn in the figure, there is inserted a gas-generating cartridge 5. The cartridge 5 contains a material 6 which on combustion produces a relatively large volume of gas, sufficient to produce a pressure within the vessel 1 of some 10 bar. The combustion of the material 6 is ignited electrically by a circuit, shown diagrammatically as a filament 7. The combustion-igniting circuit 7 is operated by a sensor 8. The gas-generating cartridge 5 has an orifice 9 which communicates with an enclosure 10 within the vessel 1. The purpose of the enclosure 10 is 6 to control the pressure rise within the vessel 1 so as to prevent the. rupture of the vessel 1 by a shock wave generated upon the operation of the gas-generating cartridge 5 and to allow the chemical reaction to start smoothly. The enclosure 10 may be made of an elastic material which expands to pressurise the extinguishing liquid 2 and cause it to rupture the membrane 4 at each of the orifices 3 in the wall of the vessel 1. The containment of the pressurising gas by the elastic enclosure 8 prevents the pressurising gas from venting preferably through the orifices 3 nearest to the gas generating cartridge 5.

The vessel 1 has an internal volume between 2 and 5 litres, the size being chosen according to the anticipated use of a given extinguisher. The vessel 1 may be made of metal or of a plastics material having suitable tensile properties, such as, glass -reinforced polyester or the material known as ABS. Another possible plastics material is the group known as polycarbonate.

The material 6 in the gas-generating cartridge 5 can be such as is used in model solid rocket engines.

Alternatively, a two-component system can be used with the two components initially separated by a membrane, which is ruptured by the operation of a thermally activated plunger, a manually operated plunger or 7 trigger. If so desired, the membrane 4 may be deposited on the inner surface of the vessel 1, where it is less likely to be subjected to abrasion. Alternatively, the membrane 4 can be replaced by plugs inserted into each of the orifices 3, by means of a painting or dripping process.

The water in the vessel 1 may contain additives such as anti-freeze, antibacterial agents, or a dye, which both provides a visual indication that a given extinguisher has been used, and facilitates the use of the invention in a security role, the water fog serving to confuse an intruder and the dye to mark the intruder.

The vessel 1 can be cylindrical in form with domed ends. This configuration retains the feature that the extinguisher, unlike existing self-contained fire extinguishers can be rolled into a fire from its periphery. on the other hand, if a number of extinguishers are formed into a static, distributed system, with either individual fire sensors or a centralised control, then an hemispherical form can be adopted for the vessel 1. with the closing plane surface providing a means of mounting the extinguisher on a wall or ceiling surface of a building.

If the vessel 1 is made of a plastics material there will be a tendency for the drops produced as the water is Cz 8 forced through the orifices 3 to become charged tribologically which will aid the dispersal of the droplets into a fog. This effect can be increased by arranging for a capacitor circuit associated with the gas- generating cartridge 5 and connected with the vessel 1 to be discharged across the vessel 1 at the same time the gasgenerating cartridge, is activated, thereby to charge it.

9

Claims

1. Apparatus capable of acting as a fire extinguisher and/or a security device, comprising a vessel having a plurality of sealed orifices disposed over its surface and means for generating in the vessel in response to an actuator impulse a pressure sufficient to cause a fluid contained in the vessel to overcome the orifice seals and to be expelled through the orifices in an atomised state.

4

2. Apparatus according to Claim 1, wherein the orifices are sealed by a continuous membrane deposited on either the inner or outer surface of the vessel.

3. Apparatus according to Claim 1, wherein the orifices are sealed by individual plugs.

4. Apparatus according to any of Claims 1 to 3, wherein there is included a cartridge containing a material which is capable of generating sufficient gas to produce the required pressure to overcome the orifice seals and there is included an inner enclosure in which the pressurising gas is admitted initially so as to reduce the risk of the operation of the gas-generating means failing to start or producing a shock wave sufficient to rupture the vessel.

5. Apparatus according to any preceding claim, wherein the gas is produced by the burning of a solid material.

6. Apparatus according to any of Claims 1 to 4, wherein the gas is produced by a reaction of two components which are initially separated and which are brought together in response to the actuating impulse.

7. Apparatus according to any preceding claim, wherein the actuating impulse is an electrical signal generated in response to the detection of a thermal source.

0

8. Apparatus according to any of Claims 1 to 6, where the actuating impulse is produced by the manual operation of a trigger or plunger.

is

9. Apparatus according to any preceding claim, wherein the vessel is made of a plastics material.

10. Apparatus according to Claim 9, wherein the plastics material is a fibre reinforced polyester material.

11. Apparatus according to any of Claims 1 to 8, wherein the vessel is made of drawn, stamped or formed metal.

12. Apparatus according to any preceding claim, wherein 25 the vessel is spherical.

13. Apparatus according to any of Claims 1 to 11, wherein the vessel is in the form of a cylinder with 11 domed ends.

14. Apparatus capable of operating as a fire extinguisher or a security device, substantially as hereinbefore described and with reference to the accompanying drawings