GB2128084A

GB2128084A - Fire extinguisher

Info

Publication number: GB2128084A
Application number: GB08228195A
Authority: GB
Inventors: Alec Moses Messulam; John Barry Ellis
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-10-02
Filing date: 1982-10-02
Publication date: 1984-04-26

Abstract

The invention relates to a fire extinguisher which comprises a pressurised container such as a aerosol canister filled with a fire extinguishing gas such as BCF gas and connected to a length of plastics tubing which is designed to act as a flame sensor. The pipe burns or softens when exposed to a flame and automatically releases the fire extinguishing gas in the direction of the source of the flame. The fire extinguisher is particularly designed for use in engine compartments for example in a motor vehicle or in a boat.

Description

SPECIFICATION Fire extinguisher The present relates to a fire extinguisher and is particularly intended for the use in a motor vehicle.

The danger of a fire in a motor vehicle has long been recognised but hitherto no satisfactory solution has been put forward for reliably extinguishing such a fire without serious hazard to the occupants of the vehicle.

In the case of racing cars, complicated extinguishing systems with several sensors positioned around the vehicle have been proposed but such systems, because of the their cost, are ruled out for normal application in a family vehicle.

Small aerosol cans for operation by the driver of the vehicle in the event of a fire have also been marketed but these are unsatisfactory for a variety of reasons. In particular on opening the bonnet of a vehicle, a through draft is created which tends to deflect the stream of gas aimed at the fire away from the flames and there is also a danger on opening the bonnet to the person attempting to fight the fire.

It is therefore cleariy desirable to attempt extinguish the fire without raising the bonnet and to this end, the present invention seeks to provide an automatic fire extinguisher which is sufficiently inexpensive to be installed in family cars.

In accordance with the present invention, there is provided a fire extinguisher which comprises a pressurised container containing a fire extinguishing gas connected to a length of pressure and/or temperature sensitive tubing designed to open the container automatically, to release the gas in the event of a fire.

Fires beneath a bonnet tend to occur either adjacent the wiring harness or the engine manifolds.

Thus, when a fire first starts there are locations within an engine compartment which are unlikely to be exposed to direct flames and the invention enables the pressurised container to be located in such a safe place far removed from the immediate source of heat while placing the tubing which acts as a flame sensor in direct proximity to where a fire is likely to commence.

The temperature and/or pressure sensitive tubing may comprise a metal tube incorporating a soldered joint made with low melting point solder so as to open automatically when the temperature rises above the solder melting point. More conveniently and more cheaply, the tubing may simply comprise a length of plastics hose which either softens and bursts or burns and bursts when exposed to a flame.

The latter solution is particularly elegant in that it enables a conventional aerosol canister of BCF gas to be employed as the pressurised container and such a conventional aerosol canister may be converted into an automatically operable fire extinguisher by the mere addition of a length of plastics tubing with a sealed end connected to the canister in a manner to open the normally provided release valve.

It will be appreciated that several plastics material are currently available on the market which are both unaffected by common extinguishants and propellants such as BCF gas and which can withstand the normal pressures in a fire extinguisher when at the usual ambient temperature in the compartment of a vehicle. Such plastics will however soften immediately on exposure to flames and in a practical experiment it was found that the fire extinguisher could be made to respond to the flame of a match before the match was fully expended.

Consequently, the plastics tubing represents an extremely sensitive means of detecting flames which can be manufactured inexpensively.

The platics tubing may comprise nylon, polyurethane etc., the composition being selected to release the gas rapidly in the event of exposure to flames, while effectively maintaining the container sealed at normal temperatures experienced in the engine compartment of a motor vehicle.

A further advantage of the use of plastics tubing as the heat sensor is that the sensing area is not localised as would be in systems employing quartzite bulbs or electronic heat sensors. Instead, the plastics tubing may be spread over all areas likely to be the first exposed to a flame and the tubing would be sensitive to flames over its entire length.

Most conveniently, the plastics tubing is layed in the engine compartment to run parallel to the wiring harness and in a part of its path, the tubing should overlie the inlet and exhaust manifolds. The installation of such a fire extinguishing system is readily within the capability of the average car owner.

Installation is simplified since same means as provided for retaining the wiring harness can be used to retain the plastics tubing. Alternatively, straps may be provided with tubing to secure it to the harness or the windscreen washer tubes normally provided under a bonnet.

Though the invention is capable of being realised as a modification of existing manually operable fire extinguishers, it is not necessary that there should be a manually operable release valve on the pressurised container and instead one may employ a conventional container as now employed for example for butane gas, in which the connection of the plastics tubing may be achieved by puncturing a rubber seal on the canister.

If it is further possible to arrange for the fire extinguisher to be operable other than automatically, by incorporating a manually releasable valve at the end of the tubing. In such a case it would be advisable to have releasable fasteners securing the tubing in position in the engine compartment.

Though the invention is primarily concerned with a fire extinguisher for an engine compartment of a motor vehicle, it will of course be evident that the invention has equal applications in boats and indeed in any enclosed space where there is risk of fire. By virtue of the fact that the fire is in an enclosed place the BCF gas once released is trapped and as a result a smaller quantity of gas is required to put out the flames efficiently. This mitigates problem experienced with car fire extinguishers in the past namely that the quantity of gas would run out before all the flames had been properly extinguished.

Claims

CLAIMS (Filed on 14 Mar 83)

1. Afire extinguisher comprising a pressurised container containing a fire extinguishing gas connected to a length of pressure and/or sensitive tubing designed to open the container automatically and to release the gas in the event of a fire.

2. Afire extinguisher as claimed in Claim 1, wherein the tubing comprises a length of plastics hose which softens or burns when exposed to a flame thereby rupturing to cause the release of the fire extinguishing gas.

3. Afire extinguisher as claimed in Claim 2, wherein the container is a pressurised container incorporating a manually operable release valve and the plastics tubing is releasably connected to the container by means of a connection which automatically opens the release valve.

4. Afire extinguisher as claimed in Claim 3, wherein a manually releasable valve is arranged at the end of the tubing remote from the canister.