US2273515A - Fire-extinguishing liquid - Google Patents

Description

Patented Feb. 17, 19 42 Karl Dachlauer, Hofheim in'f'launus, Germany, assignor, by me sne assignments, to General Aniline & Film Corporation, New York,. N. Yr, a

. corporation of Delaware No Drawing. Application October 14,1939, se-

' rial No. 299,511.

I 3Claims.

The present invention relates to a fire-extinguishing" liquid.

It isknown touse chlorinated or brominated aliphatic hydrocarbons for fire extinguishing purposes: In practice carbon tetrachloride, methyl bromide and ethylene bromide are chiefly used. Carbontetrachloride, the most usual fireextinguishing agent, however, has often proved to be insufiicient for extinguishin a fire of read ily combustible substances such as benzene. The methyl bromide. is said to have a somewhat improved fire-extinguishing action, but owing to its low boiling. point 4.5 C.) it cannot readily be used alone. The main drawback of the methyl bromide, however, is its extraordinary poisonousness. According to another proposal methyl bromide is used together with brominated hydrocarbons of higher boiling point such as ethylene bromide (boiling point 131 C.). A certain improvement as to the use is attained thereby, but the poisonousness of the brominated hydrocarbons, especiallyof the methyl bromide, is not suificiently diminished thereby.

Now I have found that liquid fire-extinguishing agents which contain at least one halogen derivative of aliphatic hydrocarbons of low molecular weight having the general formula cHrplmBln wherein m, nand a: are at least one, and m+n+x is equal to 4. Y

have a considerably better fire-extinguishing action than the agents consisting of compounds which contain in the molecule only bromine or chlorine alone. The new products are also superior to perhalogenated derivatives of the hydrocarbons, namely compounds of the character of paraffine in which all the hydrogen atoms are substituted by halogen atoms of one single kind or of different kinds. A further essential advantage ofthe new compounds for use as fireextinguishing agents according to the present invention is that, in comparison with the substances hitherto used as fire-extinguishing agents,

especially the brominatedhydrocarbons, they are considerably less poisonous, even when coming In Germany September 23, 1938 These compounds may be used per se or. in admixture with'each other or alsotogether with other known liquid fire-extinguishing agents 7 .The comparative experiments described be ow prove the improved, fire-extinguishing effect of hydrocarbons containing chlorine and bromine simultaneously: y

(1) Several iron troughs of equal capacity and shape are filled with 10 liters of light benzine each and set on fire. After a burning for 2 minutes it is tried to extinguish the fire by spraying thereon different liquids, the fire-extinguish ingeffect of which is to beexamined and compared; out of a hand fire-extinguisher of the kind generally applied for carbon tetrachloride: Such a hand fire-extinguisher consists of apressure vessel wherein an ascending tube is inserted from above which nearly'extends to the bottom of the vessel. The pressure vessel is partly filled with the extinguishing liquid and thereabove with compressed air which is fed by means of a pump or from a container. The ascending tube is connected with a spraying nozzle, a valve being intercalated. On opening this valve the fire-extinguishing liquid is pressed out of the nozzle by the action of the compressed air and-is sprayed onto the burning matter. The hand fire-extinguishers used are allof the same type and are filled each with 1 liter of liquid. The following liquids are used: methylene chloride, chloroform; carbon tetrachloride, methyl bromide, chloro-' bromomethane, ethylene bromide, 1-ch1oro-l.2- dibromoethane,- symmetrical dichlorodibromoethane and the mixture of equal parts of methyl J bromide and ethylene bromide.

With the exception of chlorobromomethane, l-chloro-1.2-dibromoethane and dichlorodibromoethane it is not possible with any of the said liquids, even not with the mixture of methyl bromide and ethylene bromide, to approximately stop the fire in the troughs filled with light benzine, though the entire content of the hand fireextinguisher has been consumed. In the case of chlorobromomethane, however, half of the content and in the case of chlorodibromoethane and of dichlorodibromoethane /3 of the content are sufiicient for completely suffocating the fire in a. trough.

(2) A sheet iron tank (length: 45 cm.,breadth: 45 cm., height: 15 cm.) is placed in the center of a chamber of incombustible material (length: 2 m., breadth: 2 m'., height: 2 m.) which is open from above and, for the purpose of a good admission of air to the burning matter, is mounted on feet. For each extinguishing experiment 4 .by the action or, the compressed air, is under a pressure of 8 atmospheres ab'ove atmospheric pressure. 48 to 51 seconds. are necessary for completely vacating the hand fire-extinguisher.

With carbon tetrachloride (CCii, boiling at 76.5" C.), dichlorodifluoromethane(CClzFz, boiling at 29 C.), trichlorofluoromethane(CCiaF, boiling at +24 C.), trifluorotrichloroethane- (CFzCLCFClz, boiling at' +47 C), or difluorotrichloroethane(CFaCLCHClz. boiling at +75 C.).

1 it is not possible in any case to extinguish the me though the entire content of the fire-extinguisher has been consumed;

Y With trichlorobromomethane (CClaBr, boiling at 104 C.) the flre is extinguished only after about 35 to 40 seconds.

With a mixture of about 80 per cent of chlorobromom'ethane and about 20 per cent of dichlorobromomethane (boiling at 70 C. to 90 C.) the fire is extinguished in the course of about I to 10 seconds, the consumption of extinguishing liquid being about 200 cc. to 250 cc.

As shown by these experiments, the extinguishing liquids according to the present invention are also superior to perhalogenated derivatives 0! the hydrocarbons, even to such containing each chlorine and bromine.

I claim: 1. The process of arresting a flame which comprises directing into the atmosphere in the neiBhborhood of the flame a ch1oro-, bromoderivative of methane of the general formula CHxClmBI'n wherein m, n and z are at least one, and m-i-n-i-z is equal to 4.

2. The process of arresting a flame which cornpr'ises directing into the atmosphere in :the

neighborhood of the flame chlorobromomethane- 3. The process of arresting a flame which comprises directing into the atmosphere in the neighborhood of the flame dichlorobromomethane.

KARL DACHLAUER.