US2936834A - Fire extinguishing method and compositions - Google Patents

Description

May 17, 1960 P. L. GoMoRY FIRE'EXTINGUISHING METHOD AND coMPosI'rIoNs Filed May 2, 1958 llllllllllllll'llll `ll'nited States Patent E FIRE EXTINGUISHIN G METHOD AND COMPOSITIONS Paul L. Gomory, Broadmoor, Bethesda, Md., assignor to Phillips Petroleum Company, 'a corporation of Delaware Application May 2, 1958, Serial No. 732,522

Claims. (Cl. 169-1) This invention relates to tire fighting methods and compositions. f In one aspect Vit relates to a method" for extinguishing `the flames `from a burning liquid. In vanother aspect it relates to a novel composition for use in extinguishing re from the surface of a burning liquid. In another aspect it relates to a composition comprising conventional re extinguishing foam containing a floatable, solid material.

Y Conventional foam-type fire extinguishing compositions have been used for many years and are well known in the nrt. For example, premixed powders comprising an acidic salt and a carbonate salt are mixed with water to produce Va gas which, along with water, provides a foam for co'oling andY smothering the iire. Such salts frequently ,fused include sodium hydrogen sulfate or aluminum sulfate and soda ash, which mixtures, when wetted with water, produce CO2 as a noncombustible gas. The CO2 is the noncombustion supporting material while the aquei ous portion of the foam cools the heated sur-face which is being vaporized from the flame heat. Foam stabilizing agents such as saponin, soap, glue, etc., have beenv used vin addition to produce a stable gas-liquid foam.

v According to my invention, to the above-mentioned conventional ingredients of lire extinguishing compositions I add a oatable solidmaterial which I nd ass'ists greatly in providing a seal between the surface of vvthe hot liquid and the atmosphere. Such solid material assists markedly in cooling thelsurface to reduce 'the Vv'olatilization of the inammable liquid.

An object of this invention is to provide an improved 4foam-type extinguishing composition.

Another object of this invention 'is to provide a foamypere extinguishing composition which is more effective than those now in common use. p l

Another object of my invention is to provide an effec- .'tive lire extinguishing composition which is relatively n- Aexpensive and simple to use and which requires little or ino additional equipment` over that already installed for i fusing conventional compositions.

Still another object of my invention is to provide a composition which is adapted Yto cool the heated liquid vsurface more rapidly than conventional compositions, and fa method for its use.

Still other objects and advantages will be realized upon v"reading the yfollowing description which, taken with the 'attached drawing, formsv a part of this specification.

ln the drawing,

Figure 1 illustrates in diagrammatic form an assembly ofy apparatussuitable for carrying out the method of this invention.'

,. Figure 2 is,y a sectional view taken on the line 2*-2 of 'ajkiinely divided, floatable, noncombustible, solid material ast ich'as popped volcanic ash. My invention, furthermore, lncludes a composition of a conventional foam producing 'composition and a finely divided, iloatable, noncombustible material. My invention also includes av method for eliminating or reducing vaporization in case cfa tire of volatile constituents from the surface of an inflammable liquid which comprises oating a mixture of an aqueous iire extinguishing foam and iinely divided,oatable, noncombustible solid on said surface, a suitable solid in one instance being a popped volcanic ash.

The terms noncombustible and noninammable as applied to the finely divided, floatable material employed as an ingredient of the herein disclosed iire extinguishing composition are used interchangeably and are considered herein to have mutually similar meanings. These terms as used in this specification and claims are understood to limit the solids only to those which are noncombustible or noninammable under -the conditions of use as disclosed and claimed herein. w i

My novel c-omposition for producing foam containing a carried solid, which solid is iloatable on the surface of a materials alone or over the use of solids alone include better coverage of the aming surface due to the iioat ing, wet solid, and foam forming a complete blanket on the surface of the liquid with the foam sealing the voids between the solid particles. Solids having a high heat absorptive capacity are preferably selected to assist the water of -the yfoam in absorbing heat from and thereby cooling the surface of the flaming liquid. f

Furthermore, the incorporation of such lioatabIe, solid material as popped volcanic ash, when incorporated into the dry acidic salt-carbonate salt mixture, `assists in preventing caking of the powder in storage.

In addition to assisting in cooling the surface of a tiaming liquid, the herein disclosed solid materials serve to reduce the heat transfer ability of the 'foam froml theV flaming vapor to the surface of the liquid.v The preferred materials are resistant to heat trans-fer, partially inherently due to their compositon and partially due to their form; therefore, they act effectively as thermal insulators to retard the ow of heat. j

Since the Hoa-table, solid materials disclosed herein are more or less inert chemically, the use of foam stabilizing materials is, in some cases, unnecessary. The desirability of a stabilizing material can be determined readily by routine test by one skilled in the art in the possession of this disclosure. Y

The main requirements ofthe solid materials which are used according to my invention are that the materials must be nonintlammable, must be iioata'ble or be capable of being converted-into a floatable -form and of being reduced to small size, and, of course, they should b e relatively inexpensive. Naturally occurring diatomaceous earth, if oatable, serves well for this purpose.

- In the drawing, reference numeral 8 identifies apipe in which water ows, from a source not shown, to my apparatus for use in producing a re extinguishing foam. A mixture of solid foam producing chemicals and, .for example, popped volcanic ash, are provided in a container 9. The water is passed through an inspirator 9a, which inspirator draws the solid materials from `container`9. The water and the solid chemicals react to form the foam The advantages of my novelV combination of materials over the conventional foam forming and this foam is passed on through an inspirator a which adds a foam stabilizer, if necessary, `from a container 10. Foam containing the stabilizer is then passed on through a line 11a, apipe 22 to one or more tanks, as tank 23, or to other containers which contain flaming liquid. Pipes 17, 18, 19 and 20 represent pipes for passage of this foam to other tanks. Each of these other tanks is, if desired, provided with the same type of foam dispersing apparatus as is tank 23. In tank 23, a manifold pipe 26 communicates by way of a check valve 23a with pipe 21 for passage of foam into the tank. Sprays 25 are strategically placed in the inner and upper portion of the tank for proper distribution of the foam. Figure V2, which is a sectional view taken on the line 2-2 of Figure 1, illustrates a suitable positioning of spray nozzles for ejecting foam into the surface of a liquid 24.

In case of a rire all that is necessary is to pump water through pipe S and this water, on passing through inspirator 9a, contacts foam producing chemicals; and the mixture, which will be dissolving foam producing chemicals and foam and oatable, solid materials of this invention, is passed on through inspirator 10a for addition of a foam stabilizer. The entire foam is then passed on through manifold pipe 22 to one or more tanks into which it is desired to spray the foam. Check valve 23a is provided to prevent backow of iluid when the re lighting system is not in use and also to prevent back'ow of fluid in case of an explosion within the tank 23.

in some instances it is desirable to add the solid oatabie material, as an aqueous slurry to the foam prior to its introduction into the tank. In this case a pipe 11 conducts foam with or without a fom stabilizer, under the inliuence of a pump 13 into a tank 14 which contains an aqueous slurry or suspension of such a solid, floatable material as popped volcanic ash. A motor driven stirrer assembly 27 is provided for maintaining the slurry in a fluid condition so that the slurry is transferrable in pipes. Foam which passes through pipe i2 into tank 14 forces slurry through a pipe 14a into a inspirator 16 for mixing with foam prior to passage on through manifold pipe 22 to one or more tanks. In some instances it is not necessary to use the inspirating action of inspirator 16, particularly' when suiicient pressure is provided by pump 13. In this case aqueous foam from pump 13 with the valve in pipe 11 closed, is pumped through pipe 12 into tank 14 and foam and slurry leave the tank through a pipe 15 or pipe 15a to manifold pipe 22. However, ordinarily, only a small fraction of the main stream of foam is by-passed through pipe 12, with the valve in pipe 11 being only partially closed, into tank 14 and the main portion of the stream passes on through inspirator 1.6 with the valve in pipe 14a being closed. If desired, the valve in pipe 14a can be opened somewhat so as to remove slurry from tank 14 by the inspirating action of .inspirator 16 in addition to passage of slurry through pipe 15 Vor pipe 15a from the tank. The pipe 15a is provided for passage of slurry from the bottom of tank to manifold 22.

The following speciiic examples illustrate dry mixtures of foam producing compositions suitable for use according to my invention. ln Example l the composition comprises l20 pounds of sodium hydrogen sulfate, 160` pounds of sodium carbonate and 40 pounds of popped volcanic` ash. In Example 2, to 120 pounds of sodium hydrogen sulfate and 166 pounds of sodium carbonate are added 50 pounds of popped volcanic ash and l pound of saponin as a foam stabilizer.

To each of the above compositons is added water at the rate of about l galion per pound of mixed salts to produce about l cubic foot of foam.

The popped volcanic ash, or other oatable, solid material, is added in a ratio from about l/s pound to about 'bi pound per pound of mixed salts. While these limits are preferred, in some instances less than ls pound, and

in other instances more than 1/2 pound, of floatable, solid material is added to the foam producing materials.

I do not intend to be limited to the above illustrative compositions. Other suitable acidic salts and carbonate salts which are known in the art can very Well be used in place of those illustrated herein. The salts, however, are mixed in dry powder form, obviously in molar ratios. The quantity of foam stabilizing material, if used, depends on the compound or compounds used, and amounts to be added are well known in the art since the stabilizers mentioned hereinabove are all well known. Usually from about 0,01 up to 1.0 weight percent, based on the dry weight of the total salt, of such stabilizers, is suflicient, However, depending on the source of water used to produce the foam and on the particular foam forming material, amounts of stabilizers outside of the abovementioned range are sometimes used.

I do not intend to be limited to the use of a dry mixture foam producing material. Liquid foam formers can also be used, such as an aqueous solution of sodium carbonate and an aqueous solution of a liquid acidic material which, when combined, produce foam. Either or both of these solutions may contain the 'lloatable, solid materials of my invention or the solid materials can be added to the foam after it has been produced by combining the two liquids.

A method of converting volcanic ash to cellular particles, or the so called popped volcanic ash, is described in U.S. Patent 2,637,702 of May 5, 1953.

The solid material as used herein should be relatively small in size, for example, such as that which passes a l-millimeter sieve. However, when employing such materials as popped volcanic ash or diatomaceous earth, these materials must not be so small as not to include buoyant pore space because one of the main points of the invention is that the solid material must be floatable upon the liquid for effective fire extinguishing. Hollow glass, metal or noncombustible resin balls are sometimes larger in outside diameter than the above mentioned 1 millimeter size. rifhey must, however, bs sufficiently small as to be handled easily by an inspirator, to flow with foam in pipes, to be sprayed through a suitable spray nozzle, etc., without appreciable breakage or deformation.

As will be evident to those skilled in the art, various modifications of this invention can be made, or followed, in the light of this foregoing disclosure and discussion, without departing from the spirit or scope thereof. While certain embodiments of the invention have been described for illustrative purposes, the invention obviously is not limited thereto.

I claim:

1. A method for reducing contact between the surface of a body of a vaporizable liquid and the surrounding atmosphere comprising the steps of forming a mixture of a tire extinguishing foam and a finely divided, non-combustible solid material, said mixture being oatable on said liquid, and applying said mixture to said surface.

2. A method for eliminating vaporization of a vaporizable constituent from the surface of a body of liquid comprising the steps of forming a mixture of an aqueous lire extinguishing foam and a finely divided, noncombustible solid material, said foam and said material being oatable on said liquid, and floating said mixture on said surface.

3. A method for eliminating combustion conditions on the surface of a body of vaporizable liquid comprising spreading a layer of `a composition comprising a lire extinguishing foam and a finely divided, floatable, non-combustible solid material, said composition being tloatable on said liquid.

4. A composition suitable for reducing contact between the surface of `a body of vaporizable liquid and the surrounding atrnosphere, said composition consisting es- `sentially or a lire extinguishing foam and a finely divided,

non-combustible solid material, said composition being oatable on said liquid. i

V5. The method ofvclaim l wherein said material is popped volcanic ash.

6. The method of claim 1 wherein said material is 5 I popped volcanic ash.

References Cited in the iile of this patent` UNITED t STATES .PATENTS Ellery et al. Nov. 21, 1922 Boyd ,----July k1, 1930 Urquhart et al Apr. 23,y 1940 Guthrie Aug. 27,"1940 Fahey et al. Jan.1 30, 1945 Hammell May 18, 1948 Teichmann et al. Apr; 30, 1957 FOREIGN PATENTS Great Britain 7.-.. Dec. 4, 193 f y

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