FIELD OF THE INVENTION

[0001] This invention relates to a fire extinguishing system and associated mobile appliance or vehicle.

BACKGROUND OF THE INVENTION

[0002] Vehicle based fire fighting equipment generally includes a water tank, a hose and a nozzle for spraying water from the tank. The vehicle generally has an on-board generator to power a pump that is used to pressurize the water for increased range.

OBJECT OF THE INVENTION

[0003] The invention seeks to provide an alternative fire extinguishing system and a mobile appliance or vehicle.

SUMMARY OF THE INVENTION

[0004] In accordance with the invention, there is provided a fire extinguishing system for a mobile appliance including:

a tank for fire retardant;

a gas storage for storing high pressure gas to be used as propellant for the water; and

a nozzle coupled to the water tank and gas storage for ejecting one or both of the fire retardant from the tank and compressed gas from the storage; wherein the gas storage is connected to an exhaust system of the mobile apparatus, to scavenge exhaust gases into the gas storage.

[0005] Preferably, the system includes a diversion valve to divert exhaust gas from an exhaust outlet to the gas storage. Preferably, the gas storage is in the form of one or more high pressure storage tanks.

[0006] Preferably, the system includes a compressor unit between the diversion valve and the gas storage to pressurize the gas for high pressure storage.

[0007] Preferably, the system includes a pump unit for pressurizing fire retardant from the tank for delivery to the nozzle.

[0008] Preferably, the tank is a water tank and the fire retardant is water.

[0009] Preferably, the system includes a water collection pipe, connected between the compressor and the tank to allow excess water generated in the compressor to be drained into the tank.

[0010] Preferably, the system includes a power generating unit for providing power for the compressor and water pump and for generating the exhaust gas for the compressed gas storage. Preferably, the power generating unit is a diesel power unit.

[0011] In another aspect, there is provided a mobile appliance, including a power generating unit, in the form of a motor or generator, and a fire extinguishing system, as described above, coupled to an exhaust system of the mobile appliance such that exhaust from the power generation unit selectively feeds into the compressed gas storage.

[0012] Preferably, the mobile appliance is a vehicle. [0013] Preferably, the nozzle is connected to a hose for fighting external fires. Alternatively, the nozzle is mounted in the vehicle, such as in a cabin or engine bay, for extinguishing on-board fires.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention is more fully described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of a fire extinguishing system; and

Figure 2 is a diagrammatic view of a vehicle fitted with the system.

ft

DETAILED DESCRIPTION OF THE DRAWINGS

[0015] Referring firstly to Figure 1, a fire extinguishing system 1 is shown as including a water tank 2, gas storage 3 for storing high pressure gas, and a nozzle 4 for ejecting a jet of water and compressed gas.

[0016] The gas storage 3 is in the form of two high pressure storage tanks 5, although more or less tanks could be used, as required. The gas storage 3 is connected to an exhaust system 6 of a diesel power unit 7 via a diversion valve 8 that diverts exhaust gases from an exhaust outlet 9, when needed.

[0017] A compressor unit 10 is positioned between the diversion valve 8 and the gas storage 3 to pressurize the exhaust gas and then deliver the gas into the high pressure tanks 5 through a pipe 11 and multidirectional valve 12.

[0018] A water collection pipe 13 is coupled between the compressor unit 10 and the water tank 2 to allow any excess water from the compressor 10 to drain into the tank 2. The water tank 2 also has a water filler 14 which can be used to top up the water level in the tank 2.

[0019] The system 1 also includes a water pump 15 for pressurizing the water for delivery to the nozzle 4. The nozzle 4 also receives an input line 16 from the gas storage 3. The nozzle can eject either the water or the gas individually but is preferably configured to mix the water and gas so that the gas acts as a propellant but also assists in atomizing the water to maximize the wetness factor of the water being jetted from the nozzle.

[0020] This means much less water needs to be used so the system 1 is very water economical while the pressurized gas/water mix also gives greater range and directional efficiency to the operator. Also, the fire extinguishing efficiency is further enhanced by mixing exhaust gas with the water as the gas is generally inert and contains a large component of C0 ₂ , which itself acts as a fire retardant.. The type and construction of nozzle suitable for mixing the pressurized gas and water would be apparent to a skilled addressee, without any further explanation being required here.

[0021] The extinguishing system can be pre-charged with pressurized gas such as by running the power generation unit before any fire fighting is required. When the extinguishing system needs to be used, the diesel power unit 7 can be operated to generate power to drive the water pump 15 and the multidirectional valve 12 can be opened at the same time so that the nozzle 4 is provided with both high pressure gas and water. During operation, the gas may become depleted so the diversion valve 8 can be opened when needed to divert exhaust gas to the compressor unit 10 and into the gas storage 4 so that a continuous source of not only propellant but additional fire retardant is available.

[0022] Although the power unit 7 has been described as a diesel power unit, any other form of power generating unit can be used, such as a conventional petrol powered motor or generator.

[0023] Turning now to Figure 2, .a mobile appliance 19 is shown, in the form of a vehicle 20 with the system 1 installed, where like parts are denoted with like reference numerals. The power generation unit in this case is the vehicle motor 21 that is connected to an exhaust system 6 that has an exhaust outlet 9 above a cabin 22 of the vehicle 20. The diversion valve 8 is positioned beneath the cabin 22 and the water tank 2 and gas storage 4 are mounted immediately behind the cabin 22, with the compressor unit 10 and water pump 15,

[0024] A nozzle 23 is mounted in engine bay 24 and another may be mounted in the cabin 22 for extinguishing on-board fires. The nozzles 23 are connected to the high pressure gas storage 4 but, if appropriate, may be isolated from the water tank 2 as, for example, the gas alone may be sufficient to extinguish a fire in the confined space of the engine bay 24 and cabin 22. In these regions, the fire may, in any event, be an electrical fire so water should not be used as fire retardant.

[0025] As mentioned above, the system 1 is suitable to allow switching between gas only delivery, water only delivery or the combined gas and water delivery.

[0026] Another nozzle 25 is designed for combined gas and water delivery for fighting external fires. The nozzle is illustrated as being attached to a hose 26 but the nozzle may instead be turret mounted to the vehicle (not shown) and operated from within the cabin 22.

[0027] As may be appreciated from the above, the invention makes use of a propellant in the form of exhaust gas high in C02, which is both readily available and inert to assist in fire extinguishing. The compressed gas can also be readily replenished, as needed. Accordingly, the invention provides a considerable advance on conventional fire extinguishing systems that simply use pressurized water.

[0028] It should also be appreciated the invention has been described principally by reference to use of water as a fire retardant, however, any other form of fire retardant such as foam or the like can instead be used, as required. [0029] The invention has been described by way of non-limiting example only and many modifications and variations may be made without departing from the spirit and scope of the invention.