GB2302849A - Fire safety system for vehicle fuel tanks - Google Patents

Abstract

The fuel tank has a system for fighting fires and/or neutralizing the fuel before a fire can start, in the event of an accident. The best example of this system is shown at figure 1 where a twin walled fuel tank 101, 102 has the space between the walls filled with a fire extinguishing/neutralizing substance. The inner of the two walls is weakened so that any impact upon the outer wall will cause a breech of the inner wall allowing stored fuels to be neutralized before an escape can take place from a breeched outer wall. The first substance to escape would always be the extinguisher/neutralizer since it buffers the stored fuels. Other examples show a system where extinguiushing/neutralizing substances are injected directly in to a single walled fuel tank to act on the fuel. This may be done using a multi-strand hose system (218, fig.2) connected to an extinguisher reservoir (204) via an impact-triggered valve (217), each hose having a series of holes (427, fig.4) along its length. Alternatively (fig.3), a perforated container (321) of extinguishant may be located in a casing (320) sealed to the wall (301) of the tank, the container being impelled into the tank by a spring (323) on impact.

Description

FUEL SAFETY SYSTEM.

An invention which relates to improving the system for storage and transmission of fuels in a combustion engined system or vehicle.

At present in a combustion engined system fuel is stored remotely from the engine in a tank. The fuel is then conducted by way of a pipe across to the engine. This is an established way of fuel storage and supply and has remained unchanged since its conception earlier this century.

A fuel cut off valve has been added to sane systems in recent years and will, in the event of a fire starting, prevent the further supply of fuel to feed the fire though it should be noted this is not its only function.

Should the system be subject to a large impact, for example a rrotor vehicle in colision with a second vehicle, then it is fairly common for the fuel tank and\or line to be ruptured allowing the escape of highly flamable fluids and explosive vapours. With the heat normally generated in such an impact a fire ball may well ensue and at the very least the whole vicinity of the scene would find itself saturated in a lethal combination of fuels and vapours ready to be ignited by a single spark or secondary fire.

In such an event the chances of any trapped person being retrieved from the wreckage has much to do with luck and many have died in such an awful way after having survived the initial impact.

This system seeks to greatly reduce the risks of fuel fed fires and the fireball that combustion engined systems are so vulnerable to.

It further seeks to neutralize any fuels or vapours that may escape from such a system and illustrate that it is doing so.

According to the invention there is provided in or around the fuel tank and or line, a fire extinguishing system activated either by heavy impact or manually in an emergency for flooding the fuel tank and or line with fuel combustion neutralizing and fire retarding chemicals either within the fuel tank or upon leakage and thus reducing the risks of serious fire and\or explosion.

One aspect of the invention relates to placing a second retention wall around the fuel tank and fuel line and filling the area between the original retention wall and second wall with fire retarding chemicals and combustion neutralizing substances supplied by a pressurised canister acting as a reservoir, this in effect turning the outer skin of fuel line and tank into a very large fire extinguisher and or fuel neutralizer.

The inner wall of the two could be made to be weaker so that in any sizable impact the weaker wall would be the first to rupture and allow all the fuel to be neutralized by the extinguisher, in such a way the inner wall could be of a plastics type material.

Should both walls be ruptured then because the extinguisher system is under pressure rather than fuel leaking out the neutralizing or fire retarding chemicals would still push into the fuel tank as well as pouring out externally and by the time any neutralized fuel did get to escape the scene will already have been well prepared with fire retarding and fuel neutralizing substances.

In a very severe impact where a total rupture of the fuel tank with explosive force were to take place the subsequent fire ball would be drowned out by the total explosion of the extinguisher itself possibly dwarfing the fuel loss (every thing could be drowned in foam).

A further cost effective system for low cost cars could be possible by using a single skinned tank with an impact sensitive valve system (similar to the system presently used on air bags) connected to a fire extinguisher . Upon a serious impact the nozzle would allow a network of tubes with holes present in the fuel tank to disperse a volume of fuel neutralizing and\or fire extinguishing fluids,powders,foams e.t.c into the stored fuel thus rendering it harmless.

A stored pressure canister within the fuel tank filled with fire retarding chemicals is also possible, The sprung firing of a torpedo like extinguisher through a special entry point into the fuel tank is also a possibility.

The invention will now further be described by way of example, with referenceto the accompanying drawings, in which figure 1 shows a cross sectional area of a fuel tank and supply line with some of my new features inset.

Item 101 is the outer wall of the fuel tank normally made of a pressed steel construction and fabricated together. Item 102 represents the inner wall of the fuel tank and is made from plastics or a thinner guage of steel than item 101, but the reverse is also possible, item 102 is held in position by item 103 which are spacers set at regular intervals so as to provide an all round cavity which could be equally spaced between the two tanks .Item 103 can also be used as a passage for the venting of a build up of gas and as a means for the insertion of fuel level monitors. Item 104 is the extinguisher reservoir bottle which is connected via item 115 to the cavity created between items 101 ,102 and is filled with foam or fire retarding chemicals under pressure.Item 106 represents the conventional fuel line sheathed by a secondary hose again placed so as to create a cavity that may be equally spaced. In to this cavity the fire solvents are again present and under pressure as supplied by item 104. Item 107 represents an automatic shut off valve activated either electronically or mechanically by impact to the vehicle or activation of the tank and which prevents the flow of neutralized fuel to the engine where it may clog a salvageable engine. Item 108 represents a standard or nonstandard male\female connector which will allow for easy removal and replacement of a spoilt fuel tank.Item 109 is the twin walled neck leading to the fuel tank from the filler cap this allows fuel to be conventionaly poured into the tank but incorporates a steel sheath to prevent damage being incurred by the more fragile inner tank when the fuel filler nozzle is inserted. Item 110 represents the standard filler cap which may or may not house the vent to dissipate the build up of gasses. Item 11 is a pressure assessment point where the pressure of the extinguishers contents can be checked during routine maintenance and if required topped up. Item 112 is a transducer which will notify the car's electrical system of extinguisher activation or a drop in pressure of the fire solvents and this could in turn lead to item 107 being activated. Items 113 and 114 represent a double adaptor which maintains the cavity either side of the fuel line and outer sheath so as to supply neutralizing and\or fire retarding chemicals to any breach of the fuel line 106, but is required to make manufacturing and installation easier. Item 116 is the fuel storage cavity which is the same as in any conventional tank.

An impact upon the outer skin of the fuel tank will cause a shattering of the rigid internal wall (102) allowing the contents stored in the cavity wall to implode in to the fuel cavity (116) neutralizing the fuels stored there, a further rupture in the tank wall (101) will cause foam and not petrol to escape since it is the foam\neutralizer that is under pressure. The same applies to the cavity created by items 105 and 106.

Upon impact shut off valve (107) is operated to ensure that the engine suffers no damage. Item 108 will, upon repair, easily disengage to allow installation of a new unit on salvageable cars.

It is for seen that with such safety features installed that an all plastic fuel tank is feasible in the near future.

It should be noted that a feature of this system is that it provides thermal insulation ito prevent diesel freezing as an added benefit FIG 2 Shows a more cost effective method of providing a safety fuel tank. Item 201 is the tank wall of pressed steel. Item 206 is the fuel line going to the car engine. Item 204 is the extinguisher reservoir.

Item 209 is the fuel filler neck. Item 215 is the supply to the tank interposed by item 217 which is an impact triggered valve system similar to that used on an air bag system. Item 214 is a standard coupling on the fuel line. Item 219 is the entry point for a multi stranded hose system item 218 which has numerous holes puncturing its length as at FIG 4 item 427.

Upon impact, the valve system at 217 is activated allowing the contents of extinguisher resevoir 204 to be released into the fuel tank and dissipated through the multi holed hose system as at FIG 4 item 427. This then neutralizes the fuel and extinguishes any fire that may have started and prevents a fire starting. It can be fitted with a fuel shut off valve at the end of fuel line (item 206).

FIG 3 shows a system where item 316 is the fuel cavity,301 the fuel tank wall,306 the fuel line, 314 the fuel line adaptor and 309 the fuel filler neck. Items 320 up to 326 show a torpedo type of fire extinguisher that is fired in to the fuel tank on or immediately after impact.

Item 320 is the outer casing of the extinguisher sealed up against the fuel wall (item 301) and with an internal opening in to the fuel tank itself. Item 321 is the torpedo structure which is fired in to the tank by a spring item 323 or some other means. Item 322 is a release mechanism which senses an impact and releases the mechanism item 324 by way of a pin item 326 being withdrawn from a hole in a shaft allowing the spring (item 323) to launch the torpedo (item 321) into the fuel tank. A series of holes 325 radially inserted around the torpedo become unsealed and allow a neutralizing and fire retarding substance to be injected into the fuel tank in a very short period of time thus stopping any fire from starting and only allowing neutralized fuel to escape from any rupture. It is further mentioned that sensor item 322 and latch mechanism items 326 and 324 may take any form as with torpedo driving mechanism item 323 which could use a gas strut, pnuematic piston ,hydraulic cylinder or any other suitable device that may come to the market in the future.

It is mentioned that it may be feasible to install a fuel fighting neutralizing device in to a modified fuel filler cal) or an interposing member or a device inserted in to the tank which may be used to retro fit existing vehicle types and may utilise any of the afore mentioned methods.

Claims (16)

AJAR;

1 Means provided in or around the fuel tank and or line of a fuel powered vehicle which means comprises, a fire extinguishing system activated either by heavy impact or manually in an emergency for flooding the fuel tank and or line with fuel combustion neutralizing and fire retarding chemicals either within the fuel tank or upon leakage and thus reducing the risks of serious fire and or explosion.

2 Means according to claim 1 in which a second retention wall is located around the fuel tank and the volume between the original retention wall and second wall contains fire retarding and fuel neutralizing chemicals supplied by a pressurised canister acting as a reservoir.

3 Means according to claim 2 in which the inner of the two walls between extinguishing chemicals and stored fuels in tank and pipe are of a deliberately weakened construction for permanent or resetable breech of inner walls.

4 jeans according to claim 1 in which the fuel line is automatically sealable upon activation of the extinguisher (activated mechanically by loss of pressure or electronically) to prevent damage to the engine by foreign substances.

5 Means according to claim 1 in which the fuel line has a quick release and reseal mechanism fitted for easily removing and cleaning of fuel line and tank.

6 Means according to claim 1 in which the fuel tank has a network of tubes with small holes inserted and connected to a shock activated (impact sensitive) valve interposed between a fire extinguisher/pressurised container reservoir.

7 Means according to claim 1 in which the extinguisher system is placed within the tank as against external fitment and where external nozzle is present for pressure testing and refilling.

8 Means according to claim 7 in which there is no double wall around the fuel tank and the extinguishing system fires directly in to the tank with or without a network of holed tubes (ref claim 6) and activated by an impact activated valve system

9 Means according to claim 8 in which the extinguisher/reservoir is fitted externally to the fuel tank.

10 Means according to claim 9 in which the extinguisher is fitted as a piston in to a sprung cylinder and is fired upon external impact in to the petrol tank to neutralize fuels and vapour stored there and to act as an extinguisher to any fires that may already have taken place in conjunction with all preceding claims.

11 Means according to all preceding claims in which the injection of pressurised fire extinguishing and fuel neutralizing agents are present in or around the fuel storage tank or line and are released on impact or manual emergency operation with the intended purpose of reducing the flamability or explosive content of the fuels stored either in a vehicle or a static power plant ie as in a generator or mobile compressor and may also be activated by electrical transducers sensing heat, impact, or a manual override of the system.

12 Means according to claim 11 in which the fuels to be protected are of a combustible nature either as a gas a liquid or a solid and where a secondary process of conversion by a catalyst may be required.

13 Means according to all preceding claims in which the fuels are diesel oil, gasoline, alcohol, propane gas and natural gas.

14 Means according to all preceding claims in which the activation of extinguisher is used by an alarm system for car immobilisation purposes.

15 Means according to all preceding claims in which the extinguisher is filled with powder, gas, foam,crystals, gels, fluids and any other type of extinguishing substances (under pressure or not), that may in future be derived or developed.

16 Means according to all preceding claims in which there is a system for retro fitting existing fuel tanks that may require a special extinguisher fuel cap , a body placed within the tank or an item interposed between tank and cap or any modification that may employ any of the previously disclosed information.