Fire extinguishers – Processes – Of extinguishing fire
Patent
1992-11-02
1998-02-03
Mitchell, David M.
Fire extinguishers
Processes
Of extinguishing fire
169 9, 169 62, A62C 3500
Patent
active
057134170
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method and apparatus for fire fighting, especially in engine rooms of ships and the like.
In spite of big amounts of water, prior art sprinkler installations have proved to be ineffective for extinguishing fires in engine rooms.
Prior art foam-extinguisher installations have also proved to be ineffective, because the foam cannot press down on the fire sufficiently. Instead, the foam is destroyed by flue gases generated at the beginning of the fire.
The object of the invention is to provide a new method and apparatus for effectively extinguishing fires that are difficult to extinguish as in engine rooms of ships and the like.
The invention is mainly characterized in that extinguishing liquid is sprayed via spray heads producing concentrated fog sprays with a strong penetrating power from a high initial operating pressure in order at least to press down a fire. Thereafter, the operating pressure is reduced so that a spread out fog-like liquid spray is provided for effective heat absorption.
Fire fighting apparatus described, e.g., in the Finnish Patent Applications 911028, 912434, 913059, 914704, 914823 and 915078 can operate at a high pressure to produce fog sprays of extinguishing liquid, e.g., water that effectively press down a fire in an engine room of a ship, for instance, with a small amount of water, e.g. 10 liters water for a fire of 10 MW. Such a small amount of water is not, however, capable of cooling down a Diesel engine, boiler or another so-called risky part in which a fire usually breaks out sufficiently that no risk of reignition remains. Moreover, the high pressure water is needed during a short time of, e.g., 10 seconds. An electric drive for this would lead to a disproportionate increase in load.
According to a preferred embodiment of the invention, accumulated energy is utilized in the form of pressure bottles, so-called hydraulic accumulators, in which nitrogen or air is suitably used as compression gas. As water put into such accumulators, the gas is compressed, whereby water and pressure energy are accumulated. The charging pressure of the hydraulic accumulators is preferably about 250 to 300 bar and the amount of accumulated water, about 200 l.
After the fire has been either extinguished or at least pressed down by concentrated fog sprays penetrating the accumulation of hot air and hot flue gases above the fire, general cooling becomes needed. For this, the concentrated fog sprays waste of restricted amount of water available. A more evenly spread out fog-like liquid spray would improve the capability of absorbing heat.
For this, preferably, the flow resistance of the individual nozzles of the spray heads is adjusted in such a way that a spread out fog-like spray formation occurs when the pressure of the hydraulic accumulators has fallen to, e.g., about 110 bar during discharge, whereby the initial counterpressure of the accumulators can be about 70 bar. In addition to saving water, the spread out fog-like spray formation is also gentle to electric installations that may be at the site.
After the hydraulic accumulators have been emptied, which usually takes about 1 minute, the accumulators are recharged. During charging, liquid can be sprayed through the spray heads with the feed line pressure of, e.g., 5 to 10 bar. If only cooling remains necessary for the prevention of reignition, the recharge of the accumulators can be interrupted at a pressure of, e.g., about 110 bar. Then the accumulators can be emptied again for producing another cooling spread out fog-like spray formation. Foam can also be applied in combination with such fog-like liquid spraying for the prevention of reignition, as will be described in greater detail later on.
In a preferred embodiment of the invention, each spray head comprises a housing, an inlet into the housing for liquid, a central channel in the housing from the inlet to a centrally positioned nozzle, and branchings extending from the central channel, the branchings leading to nozzles directed preferably obliquely to t
REFERENCES:
patent: 2537009 (1951-01-01), Allen et al.
patent: 3684019 (1972-08-01), Emmons et al.
patent: 3889756 (1975-06-01), Dunn
LandOfFree
Method and equipment for fire fighting does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and equipment for fire fighting, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and equipment for fire fighting will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-655253