GB2458674A

GB2458674A - Fire extinguishing device

Info

Publication number: GB2458674A
Application number: GB0805557A
Authority: GB
Inventors: David William Fuller
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-27
Filing date: 2008-03-27
Publication date: 2009-09-30
Also published as: GB0805557D0

Abstract

A fire extinguishing device comprises a bag 10 of flexible material filled with powder 20 and connected to a source of compressed air 32 whereby the bag can be burst to disperse the powder. Preferably the bag 10 has a mouth 26 fitted to an enclosure 30 in which a tank 32 of compressed air is mounted. The enclosure has a dish-shaped member 12 which is in communication with the interior of the bag and which is provided with apertures 18. The dish-shaped member is covered by an air-pervious fabric cover (14) at its side facing the interior of the bag in order to prevent clogging of the apertures. The extinguisher may be activated remotely using radio transmission. The powder may be polytetrafluoroethylene and the bag constructed from a thermoplastic elastomer.

Description

FIRE EXTINGUISHING DEVICE

The present invention concerns a portable dry powder fire extinguishing device.

It is known that fires can be extinguished effectively by blanketing combustible material in a layer of dry powder, thus preventing direct access to oxygen. A portable dry powder fire extinguisher using compressed air to disperse the powder was proposed as long ago as 1970 in GB1 1939892 and more recently a device using an explosive charge to disperse the powder has been proposed in CN1935295. Dry powder systems for extinguishing fire have also been proposed for incorporation into roofs or panelling of flammable liquid storage tanks and other structures, for example as described in US 2007/0119605 and US 2008/0017392.

An object of the present invention is to provide a portable dry powder fire extinguisher which is more effective and also safer to use than any previously proposed.

According to the invention a fire extinguishing device comprises a bag of flexible material filled with powder and connected to a source of compressed air whereby the bag can be burst to disperse the powder.

Therefore, at its simplest, a practical version of the device of the invention may comprise a dust-filled bag which is connected by an elongate hose to a compressed air canister and then placed in a room in which there is a fire, the canister remaining outside the room. Outlet means of the air canister can then be opened to expand and explode the bag sending the dust in all directions to blanket flames and adjacent combustible material.

For practical reasons, a hose connection to an external compressed air source is not particularly convenient. Therefore, in preferred practical embodiments of the invention the bag has a mouth fitted to an enclosure in which a tank of compressed air is mounted, the enclosure having a region which is in communication with the interior of the bag and which is provided with apertures. Conveniently, the air tank is opened by a timed mechanism or by remote control using a radio transmitter.

The invention will be described further, by way of example, by reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view showing the component parts of an exemplary device in accordance with the invention; Figure 2 shows the device of figure 1 when assembled; and Figure 3 shows the same device as it bursts open in use.

As illustrated, a preferred embodiment of the fire extinguishing device of the invention comprises a membrane of elastic material formed as a bag 10 which is filled with powder and closed off by being mounted onto a base unit 30. As shown, the bag 10 is spheroidal and similar in shape to a ball with an enlarged mouth 26. However, in other embodiments other shapes would be possible, e. g. hemispherical.

Any suitable elastomeric material may be used for the membrane of the bag 10. It may be a natural or synthetic rubber of appropriate thickness and elasticity. It may be a thermoplastic elastomer. Two specific materials identified as being suitable are a thermoplastic polyester elastomer sold by Du Pont under the registered trade mark HYTREL TPC-ET, and an elastomer/thermoplastic resin composite available from Du Pont under the name "engineering thermoplastic vulcanizate" (ETPV). These are resistent to tearing, abrasion and various types of corrosion so as to produce a robust product, as well as having required flexibility. They are also reasonably fireproof in that they will withstand high temperature for a sufficient period of time for the present purpose.

Any suitable dry powder may be used, as already known for fire quenching purposes. A specific suitable powder is polytetrafluoroethylene (PTFE) commercially available under the trade name TEFLON. Obviously any powder used must be non-flammable and non-corrosive.

The base unit 30 comprises a substantially rigid perforated dish-shaped member 12, an air-pervious cover 14 and a closure member 16. The dish-shaped member 12 may be of metal or plastics or ceramics material. The air-pervious cover 14, which is suitably a fabric, such as a non-woven textile fabric, overlies the exterior of the dish 12.

Once the bag 10 is filled with powder 20 to a sufficient content, the mouth 26 of the bag is sealed to the edge 15 of the dish-shaped member 12. The cover 14 lies between the dish 12 and the powder 20 to prevent the powder 20 clogging the apertures 18 in the dish 12, which are distributed throughout the entire area of the dish 12.

The closure member 16 then closes off the open side of the dish 12 remote from the powder-filled bag/ball 10 to provide an enclosure in which a tank 32 of compressed air can be mounted. The closure member 16 may be attached to the dish 12 by bolts or other fasteners, e.g. clips or catches, or by adhesive. Clips and/or specific recessed areas may be provided on the inner face of the closure member for reception of the aforesaid tank 32 of compressed air, also for a battery 34, and for a radio receiver device 38, both of which in use are connected electrically to an outlet mechanism of the air tank 32.

As shown, the air tank 32 has a perforated outlet duct 22 so that when the outlet mechanism is triggered air emerges rapidly over a relatively larger area than provided by a single outlet aperture. This also reduces the risk of any malfunction owing to a blocking of the outlet.

In use, the device is placed in a room where a fire needs to be extinguished, typically resting on the base of the unit 30, as shown. After a suitable interval of time, the air tank outlet mechanism is triggered by remote control using a radio transmitter 40 at a remote location to signal the receiver 38. Air rushes out of the tank 32, expanding and bursting the membrane of the bag 10 and throwing powder in all directions.

Later, the base unit 30 may be retrieved and reused with a new bag/ball 10 and a further quantity of powder 20.

The foregoing is illustrative and not limitative of the scope of the invention and details of construction and materials may vary in other embodiments. In particular, a timer device could be mounted in the enclosure of the dish 12 instead of or in addition to the radio receiver 38 so that the opening of the air tank 32 could alternatively be triggered by a timer-controlled mechanism. If a timer is used, the timer would need to be set by access from the outer surface of the closure member 16, for example via opening 36, before the device is deposited.

Claims

CLAIMS1. A fire extinguishing device comprising a bag of flexible material filled with powder and connected to a source of compressed air whereby the bag can be burst to disperse the powder.
2. A device as claimed in claim 1 wherein the bag has a mouth fitted to an enclosure in which a tank of compressed air is mounted, the enclosure having a region which is in communication with the interior of the bag and which is provided with apertures.
3. A device as claimed in claim 2 wherein the enclosure comprises a perforated dish-shaped member in communication with the interior of the bag and a closure member.
4. A device as claimed in claim 2 wherein at least the region of the enclosure which is provided with apertures and is in communication with the interior of the bag is covered by an air-pervious fabric at its side facing the interior of the bag.
5. A device as claimed in claim 4 in which the pervious fabric is a woven or non-
6. A device as claimed in any of claims 2 to 5 wherein the enclosure also includes a battery and a timer associated with outlet means of the tank to release the compressed air.
7. A device as claimed in any of claims 2 to 5 wherein the enclosure also includes a radio receiver associated with outlet means of the tank to release the compressed air upon receipt of a signal from a radio transmitter at a remote location.
8. A device as claimed in any preceding claim in which the powder is polytetrafluoroethylene.
9. A device as claimed in any preceding claim in which the elastic material of the bag is a thermoplastic elastomer.
10. A fire extinguishing device substantially as hereinbef ore described with reference to and as illustrated by the accompanying drawings.