US2259500A

US2259500A - Fire extinguishing method

Info

Publication number: US2259500A
Application number: US291349A
Authority: US
Inventors: Norman J Thompson
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-08-22
Filing date: 1939-08-22
Publication date: 1941-10-21
Anticipated expiration: 1958-10-21

Description

Oct. 21, 1941. N. J. THOMPSON 4 2,259,500

FIRE EXTINGUISHING METHOD Filed Aug. 22, 1939 Patented bot. 21, 1941 UNITED. STATES PATENT oFFlc-s I nxrmzzrs l na mi'rnon I l 'Norman J. Thompson, Wellesley, Mass. Application Alll'lllt 22, 1939, Sell N0. 291,349

2 Claims. (01. 169-14) As is well known the most dii'ilcult flres to extinguish are those 'of flammable liquids such as acetone, lacquers or Japanning preparations, ether, gasoline, etc., particularly in the case of exposed liquids such as pools spilled on the floor or used in open pans or vats in contradistinction to unexposed liquid such as liquid stored in a closed tank, the extinction of the exposed flres being rendered more difllcult because of drafts of air, such as those induced by the flre and those resulting from open windows and the like, which increase the rate oi combustion.

Objects of the present invention are to provide a flre extinguishing method ,which is simple and inexpensive to practice, which is reliable and eco-.

nomical in use, which is quick and eifective in action, which can be practiced with permanent or portable apparatus over or near open vats without interfering with the normal use of the vats. which i is universally applicable to all flammable liquids,

which has little if any tendency to impair the quality of most flammable liquids, which permits a high proportion of salvage of unburned liquid.

' which has little if any tendency to' flood the premises, which can be controlled either automatically by heat responsive means or manually as by hand operated valves, which does not require expensive liquids or gases, which does not require bulky fluid containers and which is generally superior to methods heretofore used, particularly for use in extinguishing flres in exposed places.

According to .the present invention the flre is subjected to the direct action of a spray of dis crete particles of propellant fluid such as water or water vapor, the spray preferably diverging in the form of a cone from a small nozzle opening in a substantial area,-and a gaseous flre extinguisher is entrained in'ilie spray at or near-the apex-of thescone, While the gaseous fire extinguisher aspirator nozzle. Moreover the water particles 1 i help materially to extinguish the flre, not only by their cooling chest but also by a smothering effect as they flatten upon impingement with the surface of the flammable liquid and tend to form a fllm over the surface of the liquid. Whilethe spray of water particles may be formed with a jet of steam which condenses into water vapor as it emerges from the nozzle, of course the cooling effect is greater if the spray be produced with cold water. The gaseous extinguisher which is carried to the flre by the aspirating action of the water spray not only tends to displace the oxygen in the region of the flre but its presence in and around the spray tends to prevent the spray from carrying air to the fire.

For various reasons a mixture of water particles and gaseous extinguisher is superior to a spray of either water particles alone or gaseous extinguisher alone, particularly when the water particles are sprayed directly to the flre from a.

nozzle and the gaseous extinguisher is drawn into and around a spray of water particles by aspirating action. Such a mixture will extinguish difllcult flres of certain flammable liquids such as gasoline which a water spray alone will not extinguish, and less diiiicult fires of' flammable liquids are extinguished more quickly and at less expense. Even in those cases where water alone will extinguish the flre much more water is required, thereby resulting in more water damage. When using only gaseous extinguisher on exposed flres it is diflicult to blanket the flre with the gas because of drafts, and even in cases where 4 tinguisher requires high pressures, and therefore expensive high-pressure equipment; and even preferablyconsistsin' whole or in part of carbon dioxide it may comprise any aseous fluid, such as nitrogen, boiler flue gas. or internal combusexposed flres can be extinguished with gas alone a relatively excessive quantity of gas is required. The propulsion of a stream of gaseous exthen the range of the stream is too limited for satisfactory use except in closed buildings. In the case of iires in open vats of flammable liquids the gas nozzles wouldhave to be placed too close to thesurface of the liquid to permit fixed instalwith the molecules of gaseous extinguisher; consequently the mixture of water particles and gaseous extinguisher. will carryconsiderable distances without using excessive pressure in the lations of automatic equipment without seriously interfering with the normal use ofthe vats, particularly in cleansing and lacquering establishments.

For the purpose of illustration typical embodiments of the invention are shown in the accompanying drawing in which l Y Figs. 1 and 2am side and front elevations of one installation;

F133. 3 is a vertical central'section through a modifled aspirator;

Fig. 4 is a bottom plan view of the aspirator n shown in Fig. 3; and

Fig. 5 is a view similar to Fig. 3 showing another modification. The particular embodiment of the invention I shown in Figs."1 and 2 is illustrated in association with the vat It o! flammable liquid, such as a tank of cleansing fluid or a vat of lacquer for example. The apparatus comprises a casing I! which encloses a space It serving as a mixing chamber. The casing may be supported in any suitable -way as indicated at B. Extending downwardly through an opening in the top or the easing is a pipe il terminating in a nozzle IS within the chamber it, through which the propellant fluid, such as water or steam, may be supplied under pressure. Extending through the rear endof the casing 15 is a conduit l8 terminating in a nozzle 2| within the chamber |6, the conduit l8 leading to a cylinder 22 of liquifled carbon dioxide or other suitable source of gaseous extinguisher. Thelower end of the casing I5 is formed as a separate funnel-shaped part forming a flaring continuation of the upper portion of the casing. When using water as the propellant the nozzle 19 may be of any of the well-known types which break the water stream into a divergent spray of discrete particles, and when using steam the nozzle may be of any well-known type which pro- .While the spray of propellant should issue from the nozzle is with considerable force, the gaseous extinguisher may be supplied through the outlet 2! at a low velocity which is merely sufilcient to supply the extinguisher at the desired rate. The gaseous extinguisher is carried to thefire by the force of the propellant spray, the mixing chamher It being shaped to cause a substantial amount of the gaseous extinguisher to be entrained in the spray or propellant particles. The size and is preferably such that the divergent spray substantially fills the outlet of the casing.

stiletto In the modification shown in Figs. 3 and 4 the aspirator 25 comprises a conical mixing tor is very satisfactory when using-water as the propellant.

The modified aspirator35 shown in Fig. 5 comprises a cylindrical casing 86 enclosing the-upper portion of a mixing chamber 31 which also includes a Venturi type outlet portion 38. The propellant is supplied through conduit 39 to the nozzle lit, and the gaseous extinguisher is supplied through the conduit M to the nozzle 32. This form of the invention is especially suited to the use of steam as the propellant. I

In each of the' illustrated modifications the depending fiaring portion of the mixing chamber serves not only toimprove the aspirating action but it also tends to enhance the down-draft of gaseous extinguisher around the conical spray, thereby counteracting the usual tendency of a spray of fluid to feed the fire with air drawn-to ward the fire by the spray itself.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

l. The method of extinguishing fires which comprises propelling a spray of discrete fire ex tinguishing liquid particles from an orifice direct ly to the fire and with said spray aspirating to the fire a gaseous extinguisher between and around said particles.

2. The method of extinguishing fires which comprises propelling-a conical spray of discrete fire-extinguishing water particles from an orifice to the fire and in the apex portion of said conical shape of the outlet portion 20 ot the casing it spray aspirating a gaseous extinguisher between and around the water particles, whereby the fire is subjected concomitantly to the cooling action of the water and the smothering action of the gaseous extinguisher.

NORMAN J. THOMIPSON.