US2393477A - Extinguishing agent - Google Patents

Description

EXTWGUISG AGENT William R. Orman, Los eles, Califi, assignor to Northrup Aircraft, Inc Hawthorne, calm, a corporation of California No Drawing. Application October 6, 1941, Serial No. 413,819

4 Claims.

My'invention relates to extinguishing agents of the powder type and more particularly to an extinguishing agent which is ideally adapted to immediately smother fires of intense combustion, such as, for example, magnesium fires.

Among the objects of my invention are: To provide a true extinguishing agent which is ideally adapted for extinguishing magnesium fires; to provide a powdered extinguishing agent that is non-abrasive, and therefore suitable for use in extinguishing intense fires around machine tools; to provide an extinguishing agent that will not burn in the intense heat of a magnesium fire, which will prevent the combustion from spreading and which will at the same time cause immediate retardation of the heat of combustion. and to provide an inexpensive, highly effective and easily applied extinguishing agent for use on-intense fires.

Other objects of my invention will be apparent or will be specifically pointed out in the descriptlon forming a part of this specification, but I do not limit myself to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims.

Numerous cases are on record where machinery has been damaged beyond repair due to the warpins thereof from the intense heat of burnin w esium for example, which burns at 2030 F. The use of improper extinguishing agents has often increased the ill-eflects of such fires, inasmuch as many materials which are available for extinguishing ordinary fires entirely unsuitable for the purpose of extinguishing burning metals.

For example, liquid extinguishing agents, such as for example, water, carbon dioxide, and carbon dioxide foam, all release oxygen under the reducing efiect of the magnesium, and either aid the metal combustion to burn furiously, or cause explosions, when applied to fires such as burning magnesium. Carbon tetrachloride on application to an intense fire likewise releases chlorine, causing an explosive reaction with the burning magnesium Transformer oil with a flash point of i800 for example, will extinguish metal combustion if enough is applied, but will ignite in process and therefor necessitates another extinguishing agent to quench the burning oil.

Dry agents have been also used, such as for eple, cast iron shavings, which will extinguish magnesium fires only fairly well, and only providing that the shavings are completely free from cast iron powder, fine grlndings, etc. Cement will hold combustion irom spreading, but

application of such materials.

warp and otherwise damage machinery even will not extinguish the fire. Sand will hold the combustion from spreading, but will not extinguish the fire. All of these dry materials, however, are abrasive, and therefore are not practical for use in extinguishing or controlling magnesium fires around machinery.

Graphite slag and graphite itself has been recommended for use on a magnesium fire. Such materials will hold the combustion from spreading, but will not extinguish the fire. Sulphur will prevent combustion during the melting and pouring processes of magnesium, but itself will burn furiously upon application to burning filings, powder or lathe turnings from magnesium stock. Sodium bicarbonate will burn furiously on application to a magnesium fire.

I have found however, that of all the dry materials, talc, herein defined as hydrous silicate of magnesia, an insulating mineral, can best be depended upon as an agent for holding the combustion from spreading, even though it does not extinguish combustion. Talc also is practical for use in extinguishing magnesium fires around machinery, in that it is not an abrasive and will not damage the machinery. I therefore prefer to utilize talc as a base or carrier of my true extinguishing agent, for the purpose of preventing the combustion from spreading.

However, none of the materials which can be used to prevent spread of combustion in any manner solve the problem of proper fire control, as the intense heat of combustion persists after This heat will Per cent Nitrogen 15.8 Oxygen 22.5 Hydrogen '7 Sulphur .8 Carbon 53 Phosphorus .8

I have found that during combustion, casein protein gives off the following:

(a) Hydrogenwhich results in the production of water.

(b) Carbon-which results in the production of carbon dioxide.

Nitrogen-which results in the production of nitrogen gas.

This combination of end products immediately acts to extinguish the fire.

Both the tale and the casein are preferably used in powdered form and I have found that a preferred ratio of ingredients for properly controlling intense fires may be as follows:

3 parts powdered talc (400 mesh) 1 part casein powder by weight The above mixture, when applied for example, to magnesium combustion will immediately smother the fire. In practice, I have. found that large amounts of magnesium piled around lathe beds, in chucks and on the floor under exact working conditions, will, when ignited be extinguished immediatel upon application of the talc-casein mixture. As a test of the almost instantaneous action of my extinguishing agent, an experiment was made wherein magnesium shavings were piled upon a recently lacquered surface. combustion was in progress, the talc-casein powder was applied thereto. It was thereafter found that the lacquer had not been damaged due to the quick extinguishing, and the almost immediate retardation of the heat of combustion.

. I have therefore found that the combustion of the tale and the casein not only prevents the spread of combustion but actually stops the combustion with immediate retardation of heat.

I prefer to apply the talc-casein material through a shakertype can, holding for example, about two pounds of the mixed powders. I also prefer to add magnesium carbonate as a drying This pile was ignited and when full agent, and by using about 10% of this chemical, I have found that no caking of the extinguishing agent takes place even under moist climatic conditions. Freev expulsion of the powder from the can takes place without difllculty even after the cans have been standing for long periods of time.

I wish however, to have it distinctly understood that I do not wish to be limited to my choice of talc as the material which is used for the prevention of spreading of the combustion.

Other non-abrasive materials known to prevent the spreading of combustion are deemed to be fully equivalent. It is the action of the protein powder which provides the immediate retarding on the magnesium combustion, with the tale base acting as an inert diluent having the property I, of preventing spread of combustion.

. Furthermore, other proteins such as that of soy beans for example, are deemed fully equivalent to the casein. The main virtues of. tale and casein per se is that they are inexpensive and easy to obtain on the open market.

I claim:

1. The method of extinguishing a fire of'in tense heat which comprises aplying mixed talc and casein to said fire.

2. The method of extinguishing a fire of intense heat which comprises applying to said fire a non-abrasive powder capable of preventing spread of combustion, mixed with apowdered' protein selected from the group consisting of casein and soy beans.

3. A fire extinguishing agent consisting ofapaj proximately three parts powdered talc part casein powder by weight.

4. A fire extinguishing agent consisting of approximately three parts powdered tale to one part casein powder by weight with approximately 10% magnesium carbonate as a drying asent.

to one WILLIAM BIORMAN.