US2010729A - Fire extinguishing composition - Google Patents

Description

I compositions which develop a blanket of, heavy Patented Aug. 6, 1935 Albert Langlois,

v N o Drawing.

6 Claims.

invention relates to fire extinguishing compositions and it comprises a powdered mix- ,ture of sodium bicarbonate, potassium bitartrate, bori'c acid and boraxto which I advantageously sitadd; pulverized rice and ultra-marine blue, the resulting mixture being one which-is adaptedto I be cast upon a fire such as, for example, burning .g-asolineoroil.

7 are a number of fireextinguishing com- -pounds in solid powdered form available, but

", these generally suffer from a number of disdvantages. In the flrst place, their action is I nota1ways immediate because they generally -consist of a. gas evolving-material such as bicarbonate or carbonate which does not decompose at very low temperatures. Therefore, some little timeoften elapsesbefore the fire extinguishing 4 compound begins to evolve carbon dioxide. Practically all of the present types of compositions .for this purpose contain sodium carbonate or bicarbonate. In the case of 'the bicarbonate, carbon dioxide is liberated fairly rapidly, but not immediately; sodium carbonate gives up its carbon dioxide content less readily. Very few of pounds are at all suitable for extinguishing oil the present-day solid fire extinguishing comand gasoline fires. Present-day practice in connection with this problem generally requires the use of an extinguishing compound in a liquid state, such for example as fire foam and other .foam upon the burning surface of the oil.

. p sodium bicarbonate alone.

I have now discovered that it is possible to M I create an enveloping air-excluding foam-like layer upon burning oil or gasoline from solid "extinguishing compositions. My invention makes use of the dual action of sodium bicarbonate and a tartrate whereby I am able to get an immediate evolution of carbon dioxide at temperatures much lower than the decomposition temperature of the At the same time I yalso provide in my composition an excess of 7 sodium bicarbonate so that after the reaction between the bicarbonate and the tartrate has exhausted the available tartrate, a further evolution of carbon dioxide from the surplus sodium ,bicarbonate takes place.

This means that immediately upon throwing Y my fire extinguishing compound upon the flames,

carbon dioxide is evolved by reaction between the bicarbonate and the tartrate. During the course of this preliminary evolution of carbon dioxide from this reaction, the sodium bicarbonate itself is being heated up to decomposition temperature Fall River, Mass.

Application February 2, 1934, Serial No. 709,534

whereupon it decomposes with theliberation of great quantities of non-combustible gas.

I also provide in my composition fiuxing agents, namely, borax. At the high temperature of the fire, the borax will act as a flux and combine;

with the solid decomposition product of the bicarbonate and the tartrate. The resulting molten mass is fluid and forms a film on the surface of the oil or gasoline. Since, at the same time, evolution of carbon dioxide is taking place from undeco-mposed sodium bicarbonate, the jminute bubbles of gas become disseminated through the molten borax whereby a fine foamlike, though very thin, layer forms on the surface of the burning oil. V

V I also include in my composition a relatively large quantity of boric acid. This helps in preventing any spontaneous reaction between the ,sodium bicarbonate and the tartrate while the ,fire extinguishing. compound is kept in packages prior to use. The acid also assists in the decomposition of the tartrate to tartaric acid at the time the composition is brought in contact with the flames. I also believe, although I have 'not been able to satisfy myself conclusively, that the boric acid displays considerable fluxing action as well. At least it melts at the temperature of the fire and tends to form a film-like coating over the burning surface, which coating becomes blown up or aerated with fine bubbles of carbon dioxide.

One mixture I have found very suitable for the purpose of the present invention is as follows:

Parts by weight Sodium bicarbonate 48 Potassium bitartrate 4 Boric acid 12 Borax 1% To this mixture I find it advantageous to add 6 parts by weight of pulverized rice and 1 part by weight of ultra-marine blue.

These proportions may vary within reasonable PA N FF E limits, but I prefer that the composition shall contain a major quantity of sodium bi-carbonate, that the potassium bitartrate shall be considerably less than the bicarbonate, and that the boric acid shall be less than the bicarbonate but considerably more than the bitartrate. A relatively small amount of borax is sufiicient since not very much of it is required to give an adequate fluxing action.

As pointed out above, when the composition is thrown upon the flames, the bicarbonate reacts with the tartrate according to therfollowing re action: I

NaHCO3 +KH (C4H406) KNatC-zHiOs) +H20+CO2 This reaction, as stated above, occurs atrelaa' the sodium potassium tartrate to liberate free tartaric acid which in turn decomposes to carbon dioxide and water; andthej'boric acid also combines with the sodium and potassium" oxides to give borates. These borates melt and form v a filmor layer on the burning oil; which layer contains very fine microscopic bubbles of carbon dioxide gas. r

, I find'it, advantageousjto incorporate pulverized rice as noted above. Thismaterial appears to act asfahygrosc'opic agent to prevent the if carbon 'dioxideand the foam formed therefrom; jUltra'i-marineiblue, noted above, gives added'fweight'or body to the powdered composijtion and makes it far more effective, especially when used on gasoline-fires; v o ,7 As stated abo'vej the proportions of ingredients 'canvary materiallyfrom those specificallyre- "cl te'd. j'lfhe sodium bicarbonatecan vary from to" parts, the tartratefrom 3' to 10 parts,

the boric acid from about 6 to 20 parts, and the borax from about "1' to 3 or 4 parts. However, it is desirable to' maintain fat all times a' greater;

As the sodium bi 2,010,725 I L I quantity of sodium bicarbonate, a somewhat" lesser quantity oi. boric' acid, and a still amount of'the potassium tartrate; v My composition is usedin the ordinary manner of using-powdered fire exti m i hing compositions. 'The powder is simply thrown upon the fiames','usually from a package or, cylindrical smaller metal container. 3 7 a r 7,

Having thus described what I 1. A fire extinguis ingctmsasmasampmmg a dry powdered mixture 01 sodium bicarbonate',

potassium bitartrate, boric acid and box-ax; the,

in its dry powdered condition.

'2, Arfire extinguishing composition comprising (a; dry powdered 'mixture containing a] major quantity of sodium bicarbonate, a somewhat lessmixture being adapted for casting upon'a fire; 1

enquarititybf boric acid, a somewhat lesser quan-v I f' 4 m n h ns'w w n dm 48 parts by weight'di' sodium bicarbonate, 12 parts tity of 'potassium bitartratmfind a mount '9 ct e tur i adapted! 'uponafire' in its'dry powdqred condition. 5 {powdered composition from becomingiumpy due to absorption of moisture. Moreover, it ialso iunctions to assist in the formation of the blanket by weight 91' boric a idy-4w m widow-01* Potassium mtarh-Mgtnemflz 1% weight of box-ax.

4.-A fire exting i h midfiurml a j ii-i clucu 'g pulverized r ce *and titre-Me 'blue'.'" r I "5, 3A nreextineuishing composition is in; claim.

including pulverized "rice and fi g a o my 6. -A fire extin uishing a; inclaim 3, including pulverized rice I ultra-marine blue t