US2426024A - Fire extinguisher - Google Patents

Description

19, 1 41. a. JONES Em 2,426,024

FIRE EXTINGUISHER Original Filed Jan. 30, 1943 igllli [7 7% Q J? J P swam Ms IQ. JONES d.-FL:RNDERS Patented Aug. 19, 1947 FERE EXTINGUISHER.

Elwyn i ones, Ardrossan,

and I John Flanders;

West Kiibride, Scotland, assignors. to Imperial Chemical Industries Limited, a corporation of Great Britain Continuation of application Serial No. 474;070,

January 30, 1943.

This application December 29, 1943, Serial No. 516,058: In Great Britain March 1942 1 maimr (Cl. 169-31) l l e z e; invention. relates to fire exnd which a fireextinguishng a vessel is forcibly ejected loned from acartridge cone vessel. The invention relates ly to proved or modified fire k; d and to the er m is application is a coninuation of our application Serial No. 9%,0'70, dated January 30, 1943.

Var 5 kinds of generating device have en Jloyed for the purpose of establishing a .ressure with n a fire extinguisher to re fire-eating Lug liquid from it With to produce and maintain for a ti. e a powerful jet of the liquid, directed from a safe distance for instance, acid containers assoun bicarbonate, or pressure vesssed carbon dioxide; havby the operator from finguisher.

gested to employ a caragra composition in ous combustion prodsurface of the fire intense heat procombustion of such compositions has e to certain disadvantages which this method of generating the regas pressure from achieving general adopus with such cartridges it would be heat insulating lining for or to construct it of heat resisting o provide heat insulation for parts handled by the operator. Morerial, and U which be over, l

so so great that instead of conburn progressively from its exposed to surface ins the deflagrating composition become so hot hat it undergoes spontaneous ig ticn throughout its unburned portion, whereby a violent and dangerous increase in pressure may take place within the extinguisher.

We have found that these disadvantages may be obviated and other advantages obtained by causing the combustion of a compact combustible gas generating composition capable of selfsustained combustion to take place under the surface of the fire extinguishing liquid after it has been ignited, whereby the heat generated by its combustion is effici ntly absorbed and dissipated by the liquid.

substantial portion of the Wall of the forcibly ejected by? internally developed gas pressure, aga's generating cartridge within said vessel containing-a compact composition capable of selfsustaine'd exothermic gas generating combustion, and ignition means to start its combustion, said cartridge being adapted to cause the further combustion thereof to take place under the surface of said fire extinguishing liquid, and the combustion gases to pass through said liquid. Preferably the'gas generating cartridge comprises a breech portion containing the: means of ignition, and an ejectable combustion chamber portion attached to the'breechportion and containing the compact composition, the ejectable portion being adapted to sink and remain. completely submerged under the fire extinguishing liquid when ejected; andalso to permit the combustion of the compact charge to continue" after-it has beenportion'has been'eject'ed into the liquid.

The means by'which the combustion of' the compact charge of gas-producing material is caused to continue-under the surface of the liquid while permitting the escape of the gases through the liquid to? the space above it; may advantageously consist in theprovision at the breech end of the combustion chamber'of a wall comprising vents' of suchnumber and size as to offer little resistance to the exit of the combustion gases but prevent the entry of the fire extinguishing liquid into the combustion chamber against the pressure of the emergent gases; and a space is preferably provided between the near end ofth'e charge and the vents. A sinker may advantageouslybeprovide'd'at the remote end of the chamber.

The compact self-sustained combustible gasproducing chargemay'advantageously consist of a pellet of the'nature-of blackpowder preferably of a slow burning type, or a modified blackpowder-like deflagrating composition, advantageously one in which the sulphur has been omitted or replaced by another combustible ingredient. Colloided smokeless powder compositions may also be employed, but other gas producing compositions capable of progressive combustion with or without fiame may be used, the precise nature of the compact gas-producing composition not being an essential feature of the invention. The burning surface of the compact gas-producing charge can be restricted by a closely fitting armour of non-conducting material applied to a portion of its surface. The compact charge may be of constant burning surface characteristics, or it may, if desired, be of a form providing a somewhat increasing burning surface, so long as it preserves its compact structure while burning, since the volume available for the 9X- pansion of the gases above the surface of the liquid continuously increases as the liquid is ejected, and smaller variation in the pressure as the water is ejected can thereby be obtained. These burning surface characteristics can conveniently be imposed by application of a nonconducting armour as aforesaid as is known.

Th fire extinguisher for use with a cartridge made in accordance with the present invention is provided with means for holding the breech portion of the cartridge with at least the ignition means above the level of the fire extinguishing liquid, and means co-operating with the ignition means therein to initiate the combustion when actuated by the operator. For instance the breech portion of the cartridge may include a percussion cap and a fuze leading therefrom through a gas venting aperture to the charge in the combustion chamber portion and the extinguisher body may be provided with a striker adapted to be impacted against the percussion cap. The fire extinguisher is also preferably pro vided with a filter to prevent solid particles from choking the liquid discharge tube, The body of the fire extinguisher may be made of sheet metal or other material of comparatively light construction since according to the invention no dangerous peak pressures are experienced.

The invention is further illustrated in the accompanying drawings of which Fig. 1 represents in vertical axial section the general arrangement of a fire extinguisher containing a cartridge made in accordance with the invention and Fig. 2 is an enlarged vertical axial section of one form of cartridge made according to the invention.

In Fig. 1, I is a fire extinguisher vessel, which may be made of sheet metal, synthetic resin or the like. 2 is a threaded neck and 3 is a threaded head. is a centrally perforated metal plate held between the shoulder 6 of the threaded neck 2 and a rubber washer 4 when the head 3 is screwed down on the neck 2. I is a striker head into which is threaded a striking pin 8 held by a cotter pin 9 against a gas sealing washer It by a spring H under compression. I2 is a metal wire filter protecting the internal portion 23 of the delivery pipe from being entered by any solid material from the cartridge. it represents the nozzle at the termination of the external portion of the delivery pipe, through which the fire extinguishing liquid I5 is projected.

In Figs. 1 and 2, I6 is the flanged metal base and I! the cardboard or metal cylindrical wall of the breech portion of the cartridge, which may be similar in construction to the blank cases employed for shotgun cartridges or very light cartridges. I8 is a base wad, I9 is a cap chamber, 20 is a, percussion cap, 2| a percussion cap composition, and 22 is an anvil. 23 is a fuze leading from the cap chamber L9 to the charge 21 in the ejecta-ble portion of the cartridge. The fuze 23 advantageously consists of a tube with a control filament of inflammable material such as a thread of guncotton, quickmatch, primed cambric or the like. 24 is the cylindrical wall of the ejectable charge holding and combustion chamber portion of the cartridge, which may be made of metal or other material resistant to the action of the fire extinguishing liquid. This ejectable portion is held in place in the breech portion in any conventional manner, such as by a frictional fit and even may be sealed conventionally with lacquer or the like, against ingress of liquid. Such a joint naturally is watertight but breakable under the pressure of gases developed by combustion of the charge within, 25 is a lead sinker attached by a watertight soldered joint 26 to form the remote end wall of this portion of the cartridge. The charge of gas-producing material capable of self-sustained combustion in this case consists of four superposed solid cylindrical pellets of a compressed blackpowder- like composition 21, 21, 27" and 21", each surrounded on its cylindrical surface by closely adhering layers 28, 28, 28", 28" of heat insulating material protecting the cy-- lindrical surfaces from becoming ignited, and thus making the pellets burn in an end to end direction, These insulating layers may advantageously consist of overlapping windings of insulating tape, and a continuance of this wrapping around the remote end of the pellet 21 is shown at 29. 3G is a terminal disc provided with a number of perforations through which the gases escape from the ejeotable portion of the cartridge when this has been submerged in liquid.

In certain cases it is possible to dispense with the wrapping with insulating material as, for instance, when the composition is compressed directly into a tube of poorly conducting material, in which case the tube may be proofed against the action of the fire extinguishing liquid or made of material capable of withstanding its action so as to serve as the material of the wall of the ejectable portion of the cartridge. In some cases it may be necessary to provide in addition to the fuze 23 a small amount of additional material facilitating the ignition of the gas producing composition charge, which, however, is not usually required when the latter is of a blackpowder-like nature.

The compact charge arranged as described in the above example is characterized by a constant burning surface, but it is often desirable to employ compact forms of increasing burning surface; for instance the pellets may be of successively increasing diameters; or of progressively increasing diameter individually. Longitudinally channeled forms may also be employed.

The progressive character of the gas evolution as the gas space increases owing to the forcing out of the fire extinguishing liquid and the small volume occupied by the cartridge in relation to the quantity of gas it evolves render it an advantage of the invention that a fire extinguisher of a given volume may be more nearly full or may be made of lighter construction possible with known fire extinguishers operated by internally supplied gas pressure, without increasing the risk of the extinguishers bursting.

We claim:

A fire extinguisher comprising in combination a vessel partly filled with a fire extinguishing liqthan is usually uid and having an outlet from which the liquid can lee forcibly ejected by internally developed gas pressure, a gas generating cartridge Within said Vessel containing a compact composition capable of self-sustained exothermic gas generating combustion and. an ignition means to start its combustion, said gas generating cartridge comprising a breech portion and a separably attached ejectable combustion chamber portion, said breech portion containing said ignition means, said combustion chamber portion containing a charge of said compact composition, a gas vent in the Wall of the said combustion chamher with a space intervening between the charge and the vent, and the shell of the said cartridge being water tight,

ELWYN JONES. JOHN FLANDERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,422,406 Bargar July 11, 1922 1,329,831 Evleth Feb. 3, 1920 883,679 Anderson Mar. 31, 1908

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