Fire extinguishers – Fluid systems – Gas-pressure discharge
Patent
1994-05-20
1997-05-27
Hoge, Gary C.
Fire extinguishers
Fluid systems
Gas-pressure discharge
169 71, 169 72, 169 74, A62C 1364
Patent
active
056323379
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to fire-fighting equipment, with a drive unit for extinguishing liquid.
To utilize at least one hydraulic accumulator, with a high initial charge pressure, as a drive unit for extinguishing liquid in fire-fighting equipment has been suggested in the international patent application PCT/FI92/00193, together with some preferable embodiments. A high initial charge pressure means in this context in general at least about 30 bar, but charge pressures of up to about 300 bar may well be considered.
Known hydraulic accumulators have a liquid space and a gas space separated from each other by a membrane. A relatively large portion of the volume of the hydraulic accumulator remains unutilized and, in addition, the penetration power of the liquid spray is reduced during a relatively long period when the hydraulic accumulator is being discharged at a reduced drive pressure.
The object of the invention is to provide a new fire-fighting equipment with an improved hydraulic accumulator enabling a more efficient fire-fighting.
The fire-fighting equipment according to the invention is mainly characterized in that the drive unit comprises at least one hydraulic accumulator, chargeable to a high initial drive pressure, and that the hydraulic accumulator is arranged to, at least at reduced drive pressure, deliver a mixture of liquid and gas.
The hydraulic accumulator can preferably be arranged to deliver liquid only at a high drive pressure and a mixture of liquid and gas at a reduced drive pressure.
In a preferred embodiment of the invention, the drive gas of the hydraulic accumulator is arranged to drive the accumulator liquid directly, without an intermediate membrane, the liquid being arranged to be driven out through a tube which starts at the bottom part of the liquid space of the accumulator and runs through the gas space of the accumulator to an outlet line.
The tube is provided with at least one aperture in its wall, at a desired distance from the outlet end of the tube at the upper end of the gas space, so that drive gas flows into the tube through said at least one aperture in the tube wall, when the liquid level in the hydraulic accumlator has sunk to said aperture, in order to boost the drive of extinguishing liquid.
In a preferred embodiment the tube is provided with a plurality of wall apertures at different levels, so that as the amount of liquid and the drive pressure of the hydraulic accumulator decrease the amount of drive gas mixed into the liquid increases.
The drive gas mixed into the extinguishing liquid results in a surprisingly good extinguishing effect for a surprisingly long time, i.e. it is possible to effectively utilize practically all of the liquid of a hydraulic accumulator in spite of a considerable pressure fall for the drive gas.
The foregoing preferred embodiment is, in addition, of a very simple structure and is thus very reliable.
A good automatic extinguisher is obtained with one single hydraulic accumulator. For e.g. automatic fire extinguishing installations with a need of greater capacity it is preferable to use a plurality of hydraulic accumulators in parallel. The hydraulic accumulators preferably have a common source of high pressure gas, e.g. a pressure bottle with nitrogen gas.
The nozzles included in the fire-fighting equipment are preferably made as presented in the international patent application PCT/FI92/00156, and the nozzles are preferably mounted in a spray head as presented in the international patent application PCT/FI92/00155, to produce a high pressure fog-like liquid spray with a good penetration power.
By a fog-like spray is meant a spray of small droplets having a diameter typically 30 to 100 microns and preferably set in a strong whirling motion. As earlier mentioned, by a high charge pressure is here in general meant from about 30 bar up to about 300 bar, as compared to an operating pressure of generally 2 to 10 bar in conventional sprinkler installations which produce a rain-like spray. It shall be noted, however, that the values gi
REFERENCES:
patent: 1263291 (1918-04-01), Schultz
patent: 2799466 (1957-07-01), Hickerson
patent: 2967570 (1961-01-01), Nurkiewicz
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