IL103834A

IL103834A - Method for fire extinguishing

Info

Publication number: IL103834A
Application number: IL10383492A
Authority: IL
Original assignee: Weiss Nissim
Priority date: 1992-11-22
Filing date: 1992-11-22
Publication date: 1996-08-04
Also published as: IL103834A0; DE4308688A1

Description

"AN IMPROVED METHOD FOR FIRE EXTINGUISHING" The present invention relates to a method for fire extinguishing operation. More particularly, the invention relates to. a simple and unexpensive method for an efficient fire extinguishing operation.

BACKGROUND OF THE I NVENT I ON A pail of water, the simplest and most primitive fire extinguisher means is effective, if available during the first few minutes. For fire occurring in ordinary combustible, materials, such as paper, wood, etc., one of the methods used is the so called soda-acid type, which^ contains a chemical reagent in a water solution. The operation of the extinguisher involves a chemical reaction which provides the force to expel the water solution; this operation is based on the water which cools the burning material and extinguishes the fire.

One type of equipment used in. a fire extinguishing system comprises a large tank filled with a solution of sodium bicarbonate dissolved in water and contains a bottle of sulfuric acid. Upon mixing the acid with the soda solution, carbon dioxide gas will result and through a hose connected to a pump, the aqueous solution is spread onto the fire area. This type of equipment is robust and does require large amounts of water which are not always available at-site, where the fire burst upon. The reason for the large amounts of water is due to the fact that a significant amount thereof evaporates due to the heat which prevails near the fire and thus is actually wasted. In case of fires which involve inflammable liquids, the principle of extinguishing is based on a blanketing effect, wherein foam is spread over the burning area and extinguishes the fire by avoiding the oxygen presence. In these days, the foams are used as fire extinguishers, not only for fires of inflammable liquids but also for other purposes due to their efficiency. The foams are spread onto the fire area from a big tank where large amounts of water in the order of 400 l/min together with about 20 l/min of a surfactant agent are introduced. However, there are several disadvantages to these foams: - They decompose at a relatively low temperature, which sometimes is even below that prevailing near the" fire.

- Generally, the foam has a very low stability.

- The fire extinguishing operation requires relatively large amounts of water and chemical reagents, which are not always available at-site.

- The fire extinguishing operation is not complete, Since after the foam decomposition, fire may start again.

- The foam has a high fluidity, being saturated with water, thus causing damages to the. surrounding.

The above brief review of the known prior art, indicates the long felt need for a .more efficient method for obtaining a quick fire extinguishing.

It is an object of the present invention to provide a simple method for fire extinguishing operation. It is anothe object of the present invention to provide a simple and efficient method for fire extinguishing opera-tion which does not require large amounts of water. It is a further object of the present invention to provide an improved method for fire extinguishing which enables to get a blanketing for a prolonged period of time, on the area on which the fire may reach. It is yet another object of the present invention to provide a simple method for fire extinguishing operation which may be used even by non-professional persons.

BRIEF DESCRIPTION OF THE INVENTION The invention consists in a method for an efficient fire extinguishing operation which comprises the use of a paste which is substantially water-free produced in-situ from an aqueous solution containing a surface active agent, in the presence of flue gases going out from the exhaust of a motor said paste being spread onto the fire area. Preferably, a stabilizer such as protein-containing substances may be added. Due to the heat evolved from the flue gases, the aqueous solution which contains the surface active agent, starts to evaporate being transformed into a paste. The paste is stable for at least 60 minutes and even for several hours, depending on the mixing efficiency of the flue gases with the aqueous solution, and shrinks onto the fire area- without producing water which may cause damage to the surroundings.

The method is characterized by a number of significant ad antages such as : - the fire extinguishing operation is very quick; - it requires very small amounts of reagent and water; - it is capable to provide a stable blanketing of a thick layer on the area where fire occurs even when it has a vertical shape; - the paste is not harmful to the surrounding.

DETAILED DESCRIPTION OF THE INVENTION The paste is formed from an aqueous solution containing a surface active agent at a concentration of 1 to 10% by volume and preferably 2% to 5%. In principle, any surface active agent selected from those known on the market, may be utilized. Preferred surface active agents are: ether sulfates, glycols and alcohols having more then 12 carbon atoms .

Optionally, a stabilizer such as protein-containing substances, may be added. The paste produced has a specific gra ity in .the range of between '50 g/1 to 200 g/l.

One of t e important characteristic of the paste, i:> the fact that it will remain on the ap lied surface more than 60 minutes, so that it will ensure that the fire is completely extinguished. Moreover, the paste during its formation will absorb carbon dioxide from the exhaust gases, , which is known by its beneficial effect on the fire extinguishing operation.

The paste produced according to the invention has the following main characteristics:. - is not toxic to human beings or animals; - is stable for a few hours; - is very efficient in the extinguishing operation, being capable to extinguish a basin of fuel within 5 to 10 seconds, compared with 30 to 60 seconds when a common foam was utilized; - it is capable to adhere on an inclined or even on a vertical surface; - it can be spread on a great distance; - the paste covers completely the fire region and does avoid its starting again.

The efficiency of the fire extinguishing operation is illustrated from a typical case where a fire was extinguished, using a. paste with a stability of 12 hours, obtained from a motor vehicle of 6 1 capacity, the aqueous solution consisting only of 40 1/min water and 1 i/min of a surface active agent spread through a hose of 2.5 inches.

A preferred scheme of the apparatus using the method, according to the present invention is schematically presented in Figure 1, wherein: (1) is a vessel containing water, or sea-water and a surface active agent, optionally also a stabilizer, to produce an ordinary foam; (2) represents a valve which regulates the entrance of the solution from the vessel; (3) represents a number of holes through which the solution with the surface active agent is dispersed and is passed through a' c annel (A); (4) represents the pipe to be connected to the exhaust of a motor; (5) represents a quick joint which conects the channel (A), with the pipe from the exhaust of a motor; (6) represents a valve for eliberating any excess o gases from the system; (7) represents a spray nozzle through which the solution -j is dispersed into the channel ' ( A) ; (8) and (8a), represent, networks to keep the rings or balls (9), their purpose being to assist the final ' formation of an homogeneous paste; ( 10 ) represents a quick joint which connects the channel (A) to the pipe (11) for spraying the paste on the f i re region ; ( ) a number of baffles, located in the channel (A) which impart a constriction. Instead af such baffles, one may utilize vanes placed with inverted curvatures one . . against the other. The baffles or vanes will enable a quick transformation of the solution, into a paste.

In principle the paste may be spread to. any distance, depending on the driving force of the gases from the exhaust of the motor. When a common motor vehicle was used, the paste could reach a distance of between 35 to 40 meters. Of course, a motor vehicle with a higher volume wijil provide more exhaust gases and therefore could produce more paste which would be spread at a large di stance .

\ In contrast to foams which due to their liquidity flow on a vertical area where the fire has to be extinguished, the paste obtained according to the present invention, adheres on such surface in the form" of an effective thick layer which extinguishes completely the fire and avoids its burst again. In this manner, the operator who deals with the fire extinguishing operation has to apply the paste only one time, being free to operate in any other places. This feature has in particular a significant importance for professional fire-men.

Using the method according to the present invention, it is possible to isolate the fire area, thus avoiding its spreading, by a number of paths made with the paste onto the fire area, at several distances.

The fire extinguishing . method was tested in several places and it was found that it requires only 1/10 to 1/20 of the amount of water and reagent used in the conventional method for the same fire area.

The method is applicable either by professional fire-rnen working with their container, or may be succesfully used by any one with a motor vehicle, considering that the driving force of the mixture which produces the paste, is resulting from the exhaust of the vehicle. The flue gases going out from the exhaust,, have also a particular advan- tage due to their carbon dioxide content, which is known by itself to have an extinguishing property, so that the resulted paste will become saturated with this gas. Moreover the fact that the flue gases are substantially oxygen-free, is an additional advantage for a fire extinguishing operation.

In case of a fire which occurs on a great surface, it is possible to use several motors, the flue gases from the respective exhausts being inter-connected.

It should be understood that the scheme presented in the attached Figure 1, is given only for a better understanding of the- invention , and many changes in said scheme as illustrated above may be inserted without being outside the scope of the invention. Thus, instead of using only one vessel ... with- the water and surface- active agent, it is possible that the. surface active agent will be fed separately from a small vessel through a metering pump to the tube conveying the water into the channe,' (A) wherein the paste is generated. Also, the use of the balls or rings (9) is only optional and in many- cases, may be omitted, in which case the networks will not be required.

Claims

103 ,834/3 C L A I M S :-

1. A method for efficiently extinguishing a fire which comprises: - producing a paste; and - spreading said paste onto the fire area, said paste being substantially water-free and produced in-situ from an aqueous solution containing a surface active agent and substantially oxygen-free flue gases from the exhaust of a motor, said motor being a motor from a motor vehicle and wherein said paste has a specific gravity in the range of 50 g/1 to 200 g/1.

2. The method according to Claim 1, wherein the paste is comprised of a surface active agent, exhaust from a motor and substantially no water. 3. The method according to Claims 1 or 2, wherein said surface active agent is present at a concentration of between 1% to 10% by volume. 103,834/3

3. The method according to Claims 1 or 2, wherein said surface active agent is selected from the group consisting of ether sulfates, glycols and high alcohols possessing more than 12 carbon atoms.

4. The method according to Claims 1 to 3, wherein a stabilizer is also incorporated with the surface active agent .

5. The method according to Claim 4, wherein said stabilizer is selected from protein-containing substances.

6. The method according to Claim 1, wherein said paste is saturated with carbon dioxide present in the flue gases .

7. The method according to Claim 6, wherein said paste is stable for at least 60 minutes.

8. The method according to Claims 1 to 7, wherein the paste is spread at a distance of above 35 meters. 103,834/3

9. . The method according to Claims 1 to 8, wherein the fire area is isolated by a number of pathways, made on certain distances with the paste produced according to Claims 1 to 9.

10. A method for efficiently extinguishing a fire, substantially as described in the specification and in any one of Claims 1 to 9. For the Applicant, Simon Lavie Patent Attorney