US2757744A - Fire-fighting apparatus and method - Google Patents

Description

Aug; 7, 1955 J. G. MALONE FIRE-FIGHTING APPARATUS AND METHOD 2 Sheets-Sheet 1 Filed Feb. 10. 1954 INVENTOR JAMES G. MALONE ATT( )RNEY '7, 1956 J. G. MALONE 2,757,744

FIRE-FIGHTING APPARATUS AND METI-{OD Filed Feb. 10. 1954 2 Sheets-Sheet 2 m.& I

k n A INVENTOR JAMES s. MALONE BY $26M ATTORNEY FIRE-FIGHTING APPARATUS AND METHOD James G. Malone, Sharpsburg, Md.

Application February 10, 1954, Serial No. 409,547

12 Claims. (Cl. 169-4) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a method and apparatus for extinguishing fire in tanks containing an inflammable fluid, in which the fire extinguishing operation occurs automatically in response to an abnormal increase of temperature.

The prior art of interest discloses a fire preventing and extinguishing method and apparatus which comprises a pumping device connected with a tank to extract cold portions of the liquid from the bottom of the tank and to jet them through the surface of the liquid. Thus the surface of the liquid is mechanically cooled and the rate of its evaporation reduced.

A disadvantage of this method is that it necessitates the maintenance of a motive power to run the pump in case of fire. At the time of an aerial attack such a motive power, usually electricity, would be likely to fail due to destruction of the power supply. The power lines or the electric motor itself are susceptible to failure also by the heat of the fire.

The principal object of the invention is a fire-fighting apparatus in a tank storing flammable material utilizing the heat of the fire to be extinguished to provide the energy to actuate the release of a fire-fighting medium automatically without a conventional additional motive power.

Another object of the invention is the method and apparatus for extinguishing the fire of highly flammable liquid such as of gasoline or oil, stored in a tank, by utilizing the heat energy created by the fire to jet an additional non-burning portion of the stored liquid into the flame, in an amount suflicient to cause vaporization to a vapor mixture exceeding the point of flammability.

A further object of the invention is a method and apparatus for extinguishing the fire of flammable material in a storage tank by spraying a suflicient amount of a liquid such as oil or water into the burning area to cause its evaporation there so as to utilize the resulting conversion of sensible heat into latent heat and thus cool the burning area.

Another object of the invention is the method and apparatus for the purpose described, simultaneously creating an increase of vapor mixture in the burning area beyond the point of its flammability and a decrease of the burning temperature of the area, automatically by the heat of the fire, without a conventional additional motive power or material.

Other objects of the invention will become apparent by reference to the following specification and accompanying drawings.

Fig. 1 is a plan view of a tank with a portion of the cover broken oif to show the fire-fighting system of the present invention;

Fig. 2 is a vertical cross-section along the lines 2-2 of Fig. 1;

F nite States Patent Patented Aug. 7, 1956 Fig. 3 is a detail side elevation of an inlet valve of chamber 6 of Fig. 2;

Fig. 4 is the plan view of an alternative embodiment of the present invention with a portion of the cover broken oif;

Fig. 5 is a vertical cross-sectional view along the lines 5-5 of Fig. 4.

Referring to the drawings, reference numeral 1 identifies the container, 3 the flammable liquid within which is partially immersed a firefighting apparatus comprising a plurality of sections 4 radially distributed within the container and mounted on a common frame formed of two concentric circular fluid storage chambers 6 and 7. Between these chambers is a float 8 shown as a cylindrical container concentric to them and attached between them. The float may be charged with an inert gas and is sealed. The sections 4 may be interconnected by conduits or may function independently.

Each section 4 has a plurality of distribution chambers shown as segments 9 and 9 and connected by conduit lines 10 with the chambers 6 and 7. The function of the float is to keep the assembly of sections floating within the tank at a predetermined level.

While one float has been shown, a plurality of such floats may be preferable, particularly in a tank of a larger radius, requiring a plurality of distribution chambers. The storage chambers 6 and 7 are each provided with a plurality of heat transfer elements 11, with a plurality of intake ball-valves 12 near their bottoms and with a corresponding number of thermostatic vents 13 near their tops. The vents are normally open, closing only when the ambient temperature rises above normal condition. Every distribution chamber segment 9 and 9 is equipped with a plurality of spray nozzles 14. The float chamber or chambers have a suflicient buoyancy with respect to the liquid stored to support the fire extinguishing apparatus at a fixed level to allow the heat exchange cham bers to touch the surface of the stored liquid level 15, or to slightly protrude above it. The distribution- chamber nozzles 14 and 14 are mounted on the conduit line 10 protruding from the distribution chambers 9 and 9 upwards in the direction of the flame area. They may be spaced below the liquid surface 15 at a clearance predeterr mined by the viscosity and weight of the stored liquid,

and by the pressure at which the liquid would spray at the critical burning temperature, in order to produce an optimum agitating and atomizing effect with the surface of the stored liquid.

In operation the apparatus is installed in the tank and at least two portions of it floats below the surface of the liquid. The liquid enters through valves 12 into the chambers 6 and 7 simultaneously forcing out the air through vents 13 and through conduits l0, and into the distribution chambers 9 and 9', expelling the air through nozzles 14. The outbreak of a fire in the tank instantly will raise the ambient temperature several hundred degrees, transmitting the heat into the fire fighting apparatus by conduction through the heat transfer elements 11 into the storage chambers 6 and 7 thus raising the temperature of the liquid and creating pressure therein which forces the liquid through the conduit 10, distribution chambers 9 and 9, and discharge spray nozzles 14 into the flaming space.

The nozzles 14 may be spaced below the level 15 and thus the liquid spray will stir up additional surrounding liquid above the surface. The atomized liquid forced into the flaming space immediately will extract heat therefrom to vaporize, thus converting the sensible heat of the flaming area into latent heat. Consequently the ambient temperature in the flaming area will be reduced and the vapor mixture will be increased to a concentration with air which will become nonflammable, thus extinguishing the fire.

There is a definite relationship between the flammable vapor densities of the mixtures of the various flammable liquids and their ignition limits. Gasoline mixtures, for instance, in excess of 6% of air concentration will not explode under normal atmospheric conditions. Thus the combined vapor producing capacity of the fire-extinguishing sections 4 is predetermined by the temperature at which the particular stored liquid evaporates, by its ignition temperature and its heat value and also by the latent heat value of the fire combatting liquid and by the size of the tank.

Figures 4 and 5 represent a simpler embodiment of the invention, which, while based on the principles above disclosed, eliminates the floating arrangement of the apparatus. Same reference characters identify subject matter common to the previous figures. The sections 4 are assembled and mounted in the top of the tank 1 above the liquid level in the upper vapor space. The float is eliminated. The liquid may be admitted into the apparatus through a conventional filing means including an inlet valve 12' such as shown in Fig. 5, which may be inserted for instance in the liquid line 10. In such a situation the pressure valve 12 will then be omitted. The atomizing nozzles 14 are provided with check valves, opening at a predetermined temperature or pressure and are directed into the tanks vapor space to function instantaneously upon the occurrence of a fire.

Water, preferably, may be utilized as the fire fighting material in the apparatus and method of the invention. Attention is drawn to the fact that the water as a firequenching agent was not accepted by the prior art as a suitable medium for fighting fires of oil, gasoline or other materials of a specific gravity less than that of water, because water floats these lighter materials and spreads them, keeping them exposed to the fire.

The present invention makes it practicable to employ water, but not for its possible quenching function. It utilizes its relatively high latent heat value of approximately 970 B. t. u. per pound. Each pound of water atomized into the burning area absorbs therefrom 970 B. t. u. to vaporize and thus actually cools the flaming area instantly. The subsequent superheating of the steam extracts additional heat and increases its cooling effect. The presence of the steam prevents an ingress of additional air into the burning area.

Any other liquids. flammable or not, of high latent heat value are suitable as fire-extinguishing material in cooperation with the apparatuses herein described. For the purposes of this specification such liquids will hereinafter be described as fire-extinguishing liquids.

It is to be understood that the heat conductor 11 may be connected directly to only one chamber provided with atomizing nozzles 14, and which chamber may function simultaneously as a storage and a pressure chamber.

It should be understood, that the foregoing disclosure relates only to a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. In a flammable liquid storing tank a fire extinguishing apparatus comprising at least one pressure container filled with a fire-extinguishing liquid, at least one heat transfer element in the tank space above the surface of the stored liquid connected to transfer heat to said pressure container, and at least one atomizing nozzle connected to said pressure container, said atomizing nozzle being located below the surface of the stored liquid.

2. In a flammable liquid storing tank a fire extinguishing apparatus comprising at least one pressure container filled with a portion of the stored liquid separated from the bulk, at least one heat transfer element in the tank space above the surface of the stored liquid connected to transfer heat to said pressure container, and at least one atomizing nozzle directed toward the tank space above the surface of the bulk and connected to said pressure container.

3. In a flammable liquid storing tank a fire extinguishing apparatus comprising at least one pressure container filled with water, at least one heat transfer element in the tank space above the surface of the stored liquid connected to transfer heat to said pressure container, and at least one atomizing nozzle connected to said pressure container and directed above the surface of the stored liquid, said pressure container being situated below the surface of the flammable liquid.

4. In a flammable liquid storing tank a fire extinguishing apparatus comprising at least one unit including at least one heat conductor, at least one heat transfer chamber, at least one pressure storage chamber, at least one atomizing nozzle and conduit lines connecting said heat conductor, said heat transfer chamber, said pressure storage chamber and said atomizing nozzle, means to fill said unit with a fire extinguishing liquid, and means to suspend said filled unit within said tank to keep said heat conductor exposed to the potentially burning area in said tank and simultaneously to keep said heat transfer chamber, said pressure storage chamber, said atomizing nozzle and said conduit lines below the potentially burning surface of said liquid, said conduit interconnecting lines forcing the fire extinguishing liquid when subjected to pressure by the heat of a fire, to atomize through said nozzle into the burning area.

5. The method of extinguishing a fire of a flammable liquid in a tank comprising the steps of separately storing a fire extinguishing liquid within said tank, of transferring the heat of the fire to be extinguished to said fire extinguishing liquid to effect its storage under a pressure proportionally increasing with the heat of the flame, and to atomize said separated pressurized fire extinguishing liquid into the burning area.

6. The method of extinguishing a fire of a flammable liquid in a tank comprising the steps of separately storing a portion of said liquid within said tank, of conveying the heat of the fire to the said separated portion of said liquid to effect its expansion under pressure and to atomize said pressurized portion of said liquid into the flaming area.

7. The method of extinguishing a fire of a flammable liquid in a tank comprising the steps of separately storing a fire extinguishing liquid within said tank, of conveying the heat of the fire to the said separately stored liquid to effect its expansion under pressure and of atomizing said separately stored fire extinguishing liquid below the surface of said flammable liquid, whereby the temperature within the tank is reduced by the conversion of sensible heat into latent heat and whereby the vapor concentration of the flammable liquid is increased by the agitation of the surface of the flammable liquid by the atomizing of the separately stored fire extinguishing liquid.

8. In a storage tank for flammable liquid, a fire extinguishing apparatus comprising means for separately storing a portion of said flammable liquid and means associated with said separate storage means responsive to excessive heat within the tank for converting said separately stored portion of flammable liquid into vapor and discharging said vapor into said storage tank.

9. In a fire extinguishing system for a flammable liquid storage tank, means for separately storing a portion of the flammable liquid, and means operatively associated with said separate storage means responsive to excessive heat within the tank for atomizing the separately stored portion of the fuel into said flammable liquid storage tank.

10. In a flammable liquid storage tank a fire extinguishing apparatus comprising means for separately storing a portion of the flammable liquid, heat transfer means operatively associated with said separate storage means for transferring excessive heat within the tank thereto, and atomizing means connected to said separate storage means for atomizing the separately stored portion of the flammable liquid upon transfer of heat thereto by said heat transfer means.

11. The fire extinguishing apparatus of claim 10 in which the means for separately storing a portion of the flammable liquid and the means for atomizing the separately stored portion of flammable liquid are situated below the surface of said flammable liquid.

12. In a flammable liquid storage tank a fire extinguishing apparatus comprising a container filled with a fire extinguishing liquid, heat transfer means associated with said container for transferring excessive heat within the tank into said container, atomizing means connected to said chamber for atomizing said fire extinguishing liquid upon an increase in temperature Within the tank, said container and atomizing means being located below the surface of the flammable liquid.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. IN A FLAMMABLE LIQUID STORING TANK A FIRE EXTINGUISHING APPARATUS COMPRISING AT LEAST ONE PRESSURE CONTAINER FILLED WITH A FIRE-EXTINGUISHING LIQUID, AT LEAST ONE HEAT TRANSFER ELEMENT IN THE TANK SPACE ABOVE THE SURFACE OF THE STORED LIQUID CONNECTED TO TRANSFER HEAT TO SAID PRESSURE CONTAINER, AND AT LEAST ONE ATOMIZING NOZZLE CONNECTED TO SAID PRESSURE CONTAINER, SAID ATOMIZING NOZZLE BEING LOCATED BELOW THE SURFACE OF THE STORED LIQUID.

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