RU2264242C2 - Fire-extinguishing method and device - Google Patents

Abstract

FIELD: fire-fighting, particularly to extinguish fires involving solid combustible substances and materials.

SUBSTANCE: method involves supplying fire-extinguishing composition to fire site, wherein fire-extinguishing composition is formed by mixing two solutions at burning material surface. One solution is aqueous solution of alkali silicate, another one is gelatinization coagulant and catalyst, for instance aqueous solution of bivalent or polyvalent metal salt. Gelatinization solution is made as aqueous solution of alkali silicate, for instance sodium water glass silicate or potassium water glass silicate including silicate in amount of 3.5-25.0% and silica modulus of 1.0-3.6. Gelatinization coagulant and catalyst solution is taken as aqueous solution of bivalent or polyvalent metal salt, for instance aluminum, iron (+3); titanium (+3 or +4), magnesium (+2), calcium (+2), with weight salt content of 4.5-47.9%. The obtained solutions are delivered to fire site as dispersed jets and are directed in the same point of burning material surface. When fire-extinguishing composition falls on surface to be protected or on burning surface reaction occurs between components of above solutions. The reaction continues for 1 sec. and results in solid gel layer forming. The gel layer may be stick to vertical and inclined surfaces, including ceilings.

EFFECT: reduced consumption of fire-extinguishing substance, reduced damage caused by fire-extinguishing, prevention of lower building story flooding.

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Description

The invention relates to fire fighting and can be used to extinguish fires of solid combustible substances and materials.

A known method of extinguishing fires [1], which consists in the fact that a fire extinguishing composition is supplied to the burning area, which contains two components: granular mineral fiber and from 3 to 5 weight percent liquid glass. Both components are fed simultaneously with an air stream. When mixing the components of the composition at the exit of a special device, a coating forms on the burning surface, which has fire extinguishing and heat insulating properties. The thickness of the coating depends on the time of supply of the components.

The disadvantages of this method are the high viscosity of the liquid component of the extinguishing agent, complicating the process of its supply to the fire, as well as the difficulty of removing residues of the extinguishing agent after the fire.

Closest to the method that is claimed is a fire extinguishing method [2], which involves pre-mixing equal volumes of urea-formaldehyde resin and a 25% aqueous solution of crystalline hydrate salt Al ₂ (SO ₄ ) ₃ · 18H ₂ O for the time required for gelation of the mixture , subsequent mixing of the obtained gel with water in a volume ratio (1.0-1.5): 1.0 and feeding the prepared extinguishing composition to the fire with the formation of solid foam on a burning surface.

The disadvantages of this method are the high cost of the extinguishing agent, due to the need to constantly ensure its stay on a burning surface. The latter leads to the fact that when extinguishing fires in buildings with high floors, the lower floors are flooded.

The basis of the invention is the task of reducing the cost of the extinguishing agent by retaining it on the surfaces, reducing losses from fire extinguishing by eliminating the possibility of flooding the lower floors of buildings and structures.

The problem is solved by supplying a fire extinguishing substance to the fire, which is additionally formed by mixing two solutions on the combustion surface, one of which is performed in the form of an aqueous solution of alkali metal silicate, and the second - in the form of a coagulator and gelation catalyst, for example, in the form of an aqueous solution of salts divalent or polyvalent metals.

Composition for extinguishing a fire, additionally made in the ratio of components: gelling agent solution - alkali metal silicate, for example, liquid sodium or potassium glass with a silicate module from 1.0 to 3.6, mass content of silicate from 3.5 to 25.0 percent, water - everything else; a solution of a coagulator and gelation catalyst — a salt of a divalent or multivalent metal, for example aluminum, iron (+3); titanium (+3 or +4), magnesium (+2), calcium (+2) with a mass salt content of 4.5 to 47.0 percent, water - everything else.

The method that is proposed is implemented as follows. Pre-prepared aqueous solutions of the coagulator and gelation catalyst. The prepared solutions are separately supplied to the fire in the form of sprayed jets, directing them to one area of the burning surface.

When contacted on burning or burning surfaces between the components of solutions, an interaction occurs that lasts up to 1 s leads to the formation of a layer of solid gel, which eliminates the possibility of filling the lower floors of buildings and structures (in the prototype, the time of formation of a layer of solid foam is 20-30 s) . The gel is able to be fixed on vertical and inclined surfaces, including ceilings. The gel contains more than 90 percent water. Prior to the complete evaporation of chemically unbound water, the temperature on the treated surfaces does not exceed 100 ° (in the prototype, the formation of a foam layer on surfaces that are protected from the heat of the fire does not occur). After evaporation of free water, heat will be absorbed due to desorption of water from silica gel and decomposition of metal hydroxides. At the same time and after the completion of these processes, melting and decomposition of crystalline hydrates of metal salts and the formation of a protective film will occur (in the prototype, after evaporation of water, the fire extinguishing agent component may ignite).

The result that can be obtained by carrying out the invention is to reduce the loss of extinguishing agent due to its retention on the surfaces, reducing losses from the implementation of fire extinguishing by eliminating the possibility of flooding the lower floors of buildings and structures.

Sources of information

1. Pat. 882404 USSR, MKI A 62 C 1/16. The method of extinguishing combustible materials / Ency Yauros (Finland); "A. Alstrem Osakeichtie" (Finland). - No. 2641852 / 29-12; declared 08/01/78; publ. 11/15/81. Bull. Number 42. - 2 p.

2. A.S. 1659014 USSR, MKI A 62 C 5/033; 39/00. Fire extinguishing method / V.K.Kostenko, K.M. Demenkova. I.A. Shamardina (USSR). - No. 4632400/12; declared 12/02/88; publ. 06/30/91. Bull. Number 24. - 3 p. - prototype.

Claims (2)

1. The method of extinguishing a fire, consisting in the fact that a fire extinguishing agent is supplied to the fire, characterized in that the extinguishing agent is formed by mixing two solutions on a burning surface, one of which is in the form of an aqueous solution of alkali metal silicate, and the second is in the form a coagulator and a gelation catalyst, for example in the form of an aqueous solution of salts of divalent or multivalent metals. 2. The composition for extinguishing a fire by the method according to claim 1, characterized in that the gelling agent solution is made in the ratio of components: alkali metal silicate, for example liquid sodium or potassium glass with a silicate module from 1.0 to 3.6, with a silicate mass content of 3.5 to 25.0%, water - everything else, and the second solution is made in the ratio of components: a salt of a divalent or multivalent metal, for example aluminum, iron (+3), titanium (+3 or +4), magnesium (+2 ), calcium (+2) with a mass salt content of 4.5 to 47.0%, water - everything else.