US2167232A - Fire extinguishing foam apparatus - Google Patents

Description

July 25, 1939: F. L. BOYD 2,167,232,

\ FIRE EXTINGUISHING .FOAM APPARATUS Filed June 6,1936

M60 1 mellfifi" FISHER L. BQYD Patented July 25, 1939 PATENT OFFICE FIRE EXTINGUISHING FOAM APPARATUS Fisher L. Boyd, Haverford,'Pa.', assignor to National Foam System, Inc., Philadelphia, Pa., a corporation of Delaware Application June'6, 1936, Serial No. 83,887

1 Claim.

This invention relates generally to fire extinguishing systems and more particularly to improvements in apparatus for generating and delivering foam for the extinguishment of fires 5 which might occur in dip tanks, .drain boards, cleaning tanks and other such installations wherein volatile, inflammable liquids are employed.

In the production of foam for fire extinguishing purposes the use of reacting solutions of foam forming chemicals is well known in the art, the chemicals ordinarily employed being bicarbonate of soda and aluminum sulphate. When the separate solutions of these chemicals are combined there immediately results the production of a mass of bubbles of carbon dioxide gas which is non-supporting of combustion and which may be applied in the form of a smothering blanket to the fire to extinguish the same. In order to increase the surface tension of the gas bubbles so that the foam will have a more lasting and stable quality, a stabilizer is generally added to one or the other of the chemicals, this stabilizer being usually an extract of licorice root, oak bark or some, other such material known to .be usable for the purpose.

While the use of the above described foam has long been recognized in the art as a dependable extinguishing agent in inflammable liquid fires, 30.: its application to certain types of fires is frequently eifected with difiiculty and with considerable loss of valuable time. Particularly is this true in the case of those fire hazards, such as dip tanks and the like. where the area involved is 351comparatively small and the time element is of extreme importance, it being impracticable in such instances to employ any type of apparatus except such as renders the foam automatically available toextinguish the fire.

40 .It is accordingly among the objects ofthe present invention to provide anapparatus which operates automatically to generate and deliver fire extinguishing foam tothefire hazard area, the

apparatus being not only of exceedingly compact 45 design so as to require a minimum of floorspace,

but also of a construction so simple that it may be operated and serviced by the ordinary inexperienced individual. 7 V

' A further object is to insure not only the auto- 50 matic generation of the foam within the foam tank but also the automatic discharge at a uniform rate of all of the generated foam, and to that end the apparatus is devoid of moving parts interiorly of the foam tank which'require time.

55 =to operate, the two foam forming solutions, ac-

cording to, the present invention, being brought into reacting combination by the use of a charge of compressed carbon dioxide gas or other gaseous pressure medium. Carbon dioxide gas is preferably employed because it is itself non-supporting of combustion and so combines with the generated carbon-dioxide foam bubbles to increase the fire extinguishing capabilities of the foam blanket delivered from the apparatus.

Still another and important object of the in- 10 vention is to employ a compressed charge of carbon dioxide or other gas for instantly effecting the necessary reacting combination between the normally separated basic and acid foam forming solutions, the arrangement being such that the '16 foam generating apparatus may take the form of a stationary unit in which the only operating part is a plunger provided for piercing a sealing disc to release the gaseous pressure medium from the cartridgein which it is contained. 20'

Still other objects and advantages of the invention, such as those relating to details of con- 'struction' and economies effected thereby will be apparent hereinafter.

The invention consists in the combination, con- 25 ing' drawing, a preferred construction of the apparatus is shown, it being understood, of course, that this construction is only illustrative of the principles of the invention and may be varied or modified as conditions warrant without. affecting or changing the operating principles of the apparatus.

In the said accompanying drawing: I

Figure 1 is a vertical sectional View of the apparatus constructed in accordance with and embodying the principles of the present inven- 40 tion;

Figure 2 is an enlarged sectional view of the upper part of the apparatus showing more particularly the arrangement for effecting the release of the pressure medium from the cartridge within which it is contained and the association of this cartridge with the foam generating shank;

and I Figure 3 is a view showing the apparatus in elevation and connected to a foam distribution system.

Referring now to the drawing and more particularly to Figure 1 thereof it will be observed that the apparatus of the present invention generally comprises a main tank l0 having a removable top cover II. Preferably, the upper edge of the tank is provided with an out-turned flange I2 upon which the cover I I rests and to which it is secured in any suitable manner, as by bolts or other securing devices not shown. Suspended within the upper part of the tank II] is an auxiliary vessel I3, the latter being more or less snugly fitted within the tank I and of such depth as to provide a chamber or space It between the bottom wall I of the suspended vessel I3 and the bottom wall ISA of the tank It which is several times the capacity of the vessel I3. Preferably, the upper edge of the vessel I3 is also provided with an cut-turned flange I6 which is adapted to overlie the flange I2 of the tank II] when the vessel I3 is suspended within the main tank, the flanges I2 and I6 and the marginal edge of the tank cover II being so firmly secured together as to provide an hermetically sealed unit having separate compartments I l and I1.

Fixed to and forming part of the inner vessel I3 is a discharge tube 53, the longer branch I9 of which projects through the bottom wall I5 of the vessel I3 to a point adjacent the bottom of the main tank I9. Preferably, this branch I3 of the tube is welded or otherwise secured, as at 20, to the bottom wall I5 of the vessel I3. The shorter branch 2I of the tube terminates immediately above the bottom wall E5 of the vessel I3, while the bight of the tube is located well in the upper part of the vessel I3. The tank is provided in the side wall thereof at a point just below the bottom of the vessel I3 suspended therein with a discharge outlet 22 to which is adapted to be 7 connected a conduit 23 forming part of the foam distributing system. Preferably, the discharge outlet is protected by a screen 2 5 to prevent the passage into the foam distributing system of any foreign matter which might clog the conduits and so impede the free passage therethrough of the foam. The larger chamber M, which is that provided in the tank It between the bottom I6 thereof and the bottom wall of the suspended inner vessel I3 is adapted to be filled with a solution of bicarbonate of soda, designated B, to the level shown approximately in Figure l. The acid solution which is usually a solution of aluminum sulphate is received within the vessel I I, the level of this latter solution being approximately that shown in Figure 1 which is below the upper curve of the tube I8. The acid and basic solutions are thus normally maintained in separated relation and so long as this condition exists there is no generation of foam. Immediately, however, that the acid solution, designated A in Figure 1, is introduced into the basic solution B, a reaction occurs and foam is generated in the chamber I4, the pressure of this foam so generated being sufficient to cause it to be discharged through the discharge outlet 22 and by way of the conduit 23 into the foam distributing system.

The introduction of the acid solution into the basic solution so as to result in the generation of the desired foam is effected automatically and practically instantaneously by the means now to be described. Formed in the top cover I I of the foam tank is an interiorly threaded boss 24 which is adapted to threadedly receive a removable closure cap 25, the latter being provided with a centrally disposed exteriorly threaded boss 26. The closure cap 25 and its depending boss 26 are axially bored, as at 21, and projected throughthis bore is a spring-biased plunger 28, the lower extremity 29 of which is fashioned into the shape of a punch. An annular shoulder 39 formed on point M.

the plunger limits the upward movement of the latter through the bore 21 and also serves as a seal for preventing the escape of the gaseous pressure medium or of the acid solution upwardly through said bore.

Threadedly secured to the depending boss 26 is an axially bored plug 3I having an annular sealing disc seat 32 formed in its lower extremity. Secured in turn to this plug 3I, through the intervention of an intermediate body member 33, is a cartridge 34 adapted to contain a charge of compressed carbon dioxide gas or other such gaseous pressure medium. The intermediate body member 33 is also provided with an annular sealing disc seat 35 which coacts with the seat 32 in the plug 3I to clamp therebetween a sealing disc 36 of copper or other such readily ruptureable material. The intermediate body member is further provided with a restricted passage 31, while the plug 3| is provided in its upper portion with one or more radial apertures 38, from which it will appear that when the sealing disc 36 is ruptured the gaseous mediumcontained within the cartridge 34 is immediately discharged therefrom and passes upwardly through the restricted passage 37, the ruptured sealing disc 36 and the radial passage or passages 38 into the interior of the vessel I3.

The gaseous pressure medium which is thus discharged into the chamber ll of the suspended inner vessel I3 immediately forces the acid solu-. tion A through the tube I8 into the lower chamber I of the tank in which is contained the basic foam-forming solution B. The acid and basic solutions thus combine and react in the chamber I 3 to generate the fire extinguishing foam and as the latter is generated the pressure thereof is sufiicient to force the foam out of the chamber I4 by way of the discharge outlet 22 into the conduit 23 and thence through the foam distributing system, designated generally by the reference numeral 38 in Figure 3. Preferably, this foam dis tributing system comprises a series of branched conduits the terminal extremities of which are each equipped with nozzles 39 for discharging the foam over the area to be protected. The exact form of the nozzle may vary depending upon the type of hazard which it is desired to protect against, it being preferable to employ flared nozzles for dip tank protection, deflector nozzles for drain board protection, and so on.

In order to effect the operation of the plunger 28 for piercing or rupturing the sealing disc 36 of the gaseous pressure medium cartridge, it is necessary only to strike it a sharp blow either manually or by a mechanism of the type illustrated in the drawing and which includes a weight-operated lever M3 for depressing the plunger 28 in the event of an occurrence of a fire within the protected zone. As shown in Figure 1, this lever 49 is connected by means of a cable 4| to a weight 42. the latter being held in inoperative suspended. position by a second cable 43 connected to a fixed The cable 43 includes in its length a fusible link 45 from which it will appear that in the event of a fire of sufiicient intensity to melt the fusible link, the weight 12 will no longer be restrained against dropping by the cable 43 and in so dropping will cause the lever 40 to depress the plunger 28 in consequence of which the sealing disc 36 will be pierced to release the gaseous pressure medium from the cartridge 34. The pressure medium so released from the cartridge is suificient to effect the transference of all of the acid foam-forming solution A into the chamber containing the basic foam-forming solution with the result that foam is immediately generated and delivered to the fire zone.

From the foregoing it will be apparent that the foam generating unit of the present invention is of exceedingly simple and compact design, requires little if any attention, is fully automatic and positive in operation, includes no moving parts except the disc piercing plunger and is readily adapted for recharge by the simple expedient of removing the cover II to permit the replacement of the exhausted gaseous pressure medium cartridge and the replenishing of the consumed acid and basic foam-forming solutions. If desired, the tank Ill may be equipped with a wash-out plug 46 for cleaning purposes.

It will be understood, of course, that the unit may be operated automatically by means other than illustrated in the drawing and that the construction of the unit may be varied without departing from the principles of the invention as defined in the appended claim.

What is claimed as new and useful is:

In an apparatus for generating fire extinguishing foam, in combination, a stationary vertical tank adapted to contain a foam-forming solution, a removable vessel adapted to contain a second foam-forming solution, said vessel being disposed within said tank in such manner as to maintain the two solutions normally in vertically separated relation, means affording a normally sealed communicating passage between said solutions, said means including a tube extending to a point adjacent the bottom of said tank and having a reversely bent upper end communicating with the interior of said vessel and a normally sealed charge of compressed gas disposed interiorly of said vessel and adapted when opened to release the gas to thereby force the solution in said vessel under pressure through said communicating tube to the bottom of said tank for reacting combination with the solution in the tank to form foam. 20

FISHER L. BOYD.

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