Fire extinguishers – Fluid systems – Gas-pressure discharge
Patent
1998-04-03
1999-12-07
Weldon, Kevin
Fire extinguishers
Fluid systems
Gas-pressure discharge
169 16, 169 71, 239342, 239344, 239372, A62C 1362, A62C 3500, B05B 730
Patent
active
059966998
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an installation for fighting fire, including a hydraulic accumulator which includes at least one pressure container with a space for extinguishing liquid and a space for propellant gas, a rising tube, in the pressure container, provided with a side opening and, at the lower part of the pressure container, with a feed opening for feeding extinguishing liquid into the rising tube and further to at least one nozzle.
2. The Prior Art
Such installations are known from, for example, WO 94/08659. The principal of operation is that only liquid in a mist-like, penetrating form is initially sprayed from the nozzle, after which gas is mixed into the liquid through said the openings. A reduction of the pressure in the pressure container generally produces a spray with a larger drop size out of the nozzle. Owing to the feeding of gas, the drop size of the extinguishing medium discharged from the nozzle can be reduced. These known installations largely function very well; however, in some applications, it would be desirable to be able to reduce the size of the drops discharged from the nozzle even more, after the initial spraying with a great penetration, than what has been possible with the known hydraulic accumulators and nozzles. The mixing of a large amount of gas into a small amount of liquid has been relatively difficult to achieve in practice. An enlarging of the side openings in the rising tube has not produced the desired result, but by reducing the diameter of the rising tube, it has been possible to improve the intermixing of gas somewhat. However, a reduction of the diameter of the rising tube increases the pressure losses as the flow resistance of the liquid in the rising tube increases, and sufficient liquid cannot be obtained from the pressure container upon emptying the container. By being able to produce very small droplets, the amount of extinguishing liquid that is used could be minimized and, simultaneously, if water was used as the extinguishing liquid, the water damages would be minimal. This has not always been possible to achieve to such a degree as one would have wished.
SUMMARY OF THE INVENTION
The present invention relates to a new installation for fighting fire by means of which a very finely divided mist, when a pressure accumulator is used, can be easily produced at the final stage of the extinguishing, after the extinguishing with a mist-like liquid spray with a great penetrating ability and a relatively large drop size has initially been started. The installation can, if desired, easily be realized by mixing gas into the extinguishing liquid already when the emptying of the pressure container is started.
To produce such an extinguishing medium with a very finely divided mist with extremely small droplets, the invention is characterized in that the rising tube of the pressure container has a throttle in an area below the side opening.
By arranging the throttle below the lowermost side opening, gas can flow efficiently in through all the side openings, when the liquid level has sunk below the lowermost side opening. If the throttle was located above the lowermost side opening, only liquid could flow in through the lowermost side opening at the end of the emptying of the pressure container.
By arranging side openings at at least three different height levels in the rising tube, good results are achieved for many applications. In some cases, it would be possible to arrange side openings only at two different height levels or only one side opening.
Preferably, the pressure container is filled with water or a water-based liquid, whereby a gas source which is filled with nitrogen and which has a pressure in the range of about 60 to 200 bar is coupled to the pressure container. By using nitrogen, an extinguishing medium with very small droplets is obtained when nitrogen and water are intermixed. The extinguishing medium weighs slightly more than air, wherefore it will sink to the lower part of a room in whi
REFERENCES:
patent: 281942 (1883-07-01), Sutton
patent: 3870069 (1975-03-01), Etter
patent: 5676210 (1997-10-01), Sundholm
Derwent Abstract No. 91-49577/07, week 9107, abstract of SU 1570736 entitled, "Foam Jet Fire Extinguisher . . . on Float" Jan. 9, 1988 to E Mine Rescue Res.
Derwent Abstract No. 89-315041/43, week 8943, Abstract of SU 1740307 entitled "Powder-Type Fire Extinguisher . . . Agitates Powder" of Mar. 8, 1987 to M.E. Azovskov.
International Publication No. WO 94/08659 to G. Sundholm entitled, "Method and Installation for Fighting Fire" dated Apr. 28, 1994.
Evans Robin O.
Weldon Kevin
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