US2988343A - Mechanical foam generator - Google Patents

Description

June 13, 1961 T. B. EDWARDS ETAL MECHANICAL FOAM GENERATOR Filed Aug. 11, 1958 KN NN vill u Ell I w wN in mv m .NRN

United States Patent F Theodoric B. Edwards, 531t1 Neptune Drive, Alexandria,

Va., and James E. Malcolm, 6209 N. 27th St., Arlington, Va.

Filed Aug. 11, 1958, Ser. No. 754,506 11 Claims. (Cl. 261-25) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to improvements in means for mechanical generation of foam for extinguishing tires.

A principal object of the invention is to provide means for producing a high quality foam by mechanically mixing air with a previously mixed solution of Water and foam liquid.

Another object of the invention is -to provide a device of simple design and compact construction with convenient means for adjusting the amount of the air to be mixed with Ithe premixed water and foam liquid solution.

Further objects and a more complete understanding of the invention may be obtained by referring to the following description and claims taken in conjunction with the accompanying drawings -which show an illustrative embodiment of the construction forming the basis of the invention and in which- -FIG. 1 is a central vertical sectional view of the devlce;

FIG. 2 is a top view showing one form of the adjustable sleeve which controls the admission of air;

FIG. 3 is a cross sectional view taken at 3 3 on FIG. l; and

FIG. 4 is a cross sectional view taken at 4-4 on FIG. 1.

Referring to FIG. 1, inlet pipe 1 gradually increases in diameter to form housing 7, and housing 7 then decreases in diameter to form nozzle 16. Connecting nozzle 16 to housing are -webs 17 (FIG. 3). Water turbine 8 is attached to shaft 12 and is mounted within housing 7 by means of support 9 having webs 10l aixed to housing 7. Shaft 12 passes through nozzle 16. Compressor 20 is attached to shaft 12 and is mounted within housing 19 by means of support Z3l having Webs 24 afxed to housing 19. Compressor has rotating blades 21 and stationary blades 22 which are affixed to housing 19.

Referring to FIGS. 2 and 4, sleeve 15 slides in telescopic fashion on housing .15'. When sleeve 15 abuts ange 26, opening 11 is completely closed. Sleeve 15 may be variably adjusted so that opening 11 is completely closed, partially open, or fully open. It is obvious that sealing gaskets may be used at ange 26 if an airtight seal is desired at this point. Due to the converging configuration of the nozzle 16 where it enters the mixing chamber 18, a varying volume of air may be admitted to the mixing chamber as the sleeve 15' is moved from the fully closed position to the fully open position. The movement of sleeve 15 is controlled by a swinging yoke lever and connecting rod arrangement in which handle 2 with side arms 3 move on fulcrum 6 and connecting rods 13 are pivoted to side arms 3 at 5 and to sleeve 15 at 14.

The apparatus operates as follows. Referring to FIG. 1, a premixed solution of water and foam liquid enters inlet pipe 1 under pressure from an external source and strikes water turbine 8 causing it to rotate shaft 12., which in turn causes rotating blades Z1 of compressor 20 to rotate correspondingly. After the solution passes water turbine 8, it emerges from nozzle 16 into chamber 18 in a jet action, drawing air into chamber 18` through opening 11. The amount of air entering through opening 11 is manually controlled through movement of sleeve 15' Patented `utne 13, 1961 ICC . 2 increasing or decreasing the size of opening 11. The air and solution in chamber 18 pass to compressor Z0. The air is beaten into the solution by blades 21 and 22, and the resulting foam is discharged from outlet pipe 25.

No detailed discussion of the variations in pressure and velocity heads at the expanded and constricted sections along the foam generator has been included since such phenomena are well known to those skilled in the art.

Although a preferred form of this invention has been described, the principles herein taught may be embodied in other forms of construction within the scope of this invention. For example, such forms may use as means for adjusting sleeve 15' a handle or gripping means ailxed directly to the sleeve, or the sleeve 15 may have a screwthread arrangement with housing 15 so that sleeve 15 may be adjusted with relation to housing 15 by rotational movement.

We claim:

1. Apparatus for producing' tire-extinguishing foam, comprising a foam-producing nozzle assembly including an injection section deiining a nozzle chamber and a mixing section in communication with the nozzle chamber and dening a foam-producing chamber, the nozzle chamber having an intake for receiving foam-forming liquid from a supply thereof and having a nozzle-discharge outlet extending into the foam-producing chamber and' adapted to deliver foam-forming liquid as a jet thereof into the foam-producing chamber, the nozzle discharge outlet of the nozzle chamber having an orifice entering. into and enclosed by an open intake end of the foamproducing chamber, the foam-producing chamber terminating in a foam-discharging nozzle and including a compressor zone progressively restricted towards and in advance of the foam-discharging nozzle, the open intake end of the foam-producing chamber defining an annular air intake opening for admitting air into the foam-producing; chamber responsively to a venturi effect and suction pro duced by the jet of foam-forming liquid injected into the foam-producing chamber from the nozzle-discharge outlet fromthe nozzle chamber, liquid-operated motor means including liquid-operated turbine propeller blades mounted axially horizontally in the nozzle chamber and amotor shaft rotatably connected to the turbine blades axially thereof and extending horizontally through the orilce of the nozzle-discharge outlet of the nozzle chamber and terminating in the restricted compressor zone of the foam-producing chamber adjacent to the foam-dis charging nozzle of the foam-producing chamber, means for rotatably mounting the motor shaft together with the turbine motor propeller blades, rotation of the baldes and shaft being effected by impingement of the foamforming liquid against the blades, compressor means mounted on the shaft in the compressor zone of the foam-producing chamber and rotatable with the shaft, the compressor means on the shaft being a plurality of spaced blades, a second series of spaced compressor blades iixedly mounted in the restricted compressor zone of the foam-producing chamber and extending therefrom intermediate the blades on the shaft and being complementary thereto, the rotatable blades and the fixed blades cooperatively impacting thefoam-forming liquid with air drawn in-to the foam-producing chamber through the open intake end thereof to produce tire-extinguishing foam which is projected from the foam-producing chamber through its foam-discharging nozzle, thereby obviating all application and use of any extraneous source of power to any portion of the apparatus except driving energy for the motor propeller blades derived from injection of foamfornn'ng liquid against the blades.

2. The apparatus dened by claim 1, further including adjustable control means mounted on the foam-producing chamber and coacting with the open intake end of the said chamber for electing a variable control of Volumes of air-passing through the intake end in-to the said chamber, and actuating means for the control means for adjustablyvarying the intake of air throughk the intake end of the foam-producing chamber.

3. The apparatus dened by claim 2 wherein the adjustable control means include a sleeve on the foam-producing chamber and telescopically slidable relativey thereto, a peripheral abutment flange on the nozzle chamber engageable by the sleeve when the latter is in its fullest forward position covering the intake end of the foamproducing chamber and operating means for the sleeve including a lever pivotally mounted on the nozzle chamber and actuating links connecting` the lever and the sleeve for enabling selective advancement and retraction of the sleeve with respect to the intake end of the foam-producing chamber.

4. The apparatus defined by claim 1 further characterized by the nozzle chamber being dened by a casing which enlarges from the intake to a zone of maximum internal diameterV and then decreases to the nozzle-discharge outlet, the turbine rotor blades being mounted in the chamber within the zone of maximum internal diameter thereof.

5. The apparatus dened by claim 1 in which the nozzle-discharge outlet for the nozzle chamber projecting into the foam-producing chamber through the open intake end thereof is restricted in diameter for producing by jet action of liquid issuing therefrom into the foamproducing chamber a venturi eifect in `the foam-producing chamber, thereby drawing by suction through the open intake end of the foam-producing` chamber, requisite amounts of atmospheric air for mixing with the liquid to produce the foam.

6. The apparatus dened by claim 1, further characterized by the compressor means in the foam-producing` chamber including a plurality of spaced compressor blades carried by the shaft of the liquid-actuated motor and extending intermediate the xed blades mounted in the restricted zone of the foam-producing chamber for raising the pressure of an intermixing the air and the liquid in the foam-producing chamber for producing the foam substantially immediately prior to its delivery from the foam-producing chamber.

7. The apparatus dened by claim l further characterized by liquid pressure in the nozzle chamber hecoming decreased to approximately atmospheric pressure responsively to actuation of the .propellerblades, the

energy of the liquid in lthe nozzle chamber being con- Y verted inthe enlarged portion of the nozzle chamber for actuating the propeller blades during passage of the liquid through the nozzle chamber, the open intake end of the foam-producing chamber admitting atmospheric air into engagement with liquid introduced into the foam-producing chamber from the nozzle chamber and passing through the foam-producing chamber, the compressor means in the compressor zone of the foam-producing chamber exerting a beating action on the liquid and the air in the compressor zone for increasing mixing of air and liquid to promote formation of the foam and, substantially immediately prior to discharge of the foam from the foam-producing chamber, increasing pressure of the foam to an amount substantially higher than what is possible by venturi action alone, thereby obtaining a correspondingly greater stream range for discharged foam.

8. Apparatus for producing fire-extinguishing foam, which comprises a foam-producing nozzle assembly including an injection section defining a nozzle chamber, an elongated aspirating and mixing chamber `defining a foamproducing chamber, and a liquid-operated motor for the nozzle chamber and the foam-producing chamber, the nozzle chamber having an intake for admission. of liquid foam-forming material into the chamber and a discharge nozzle `for discharging the foam-forming material into ett) liquid-operated motor comprising turbine blades mounted in the nozzle chamber adjacent to the liquid intake, a,

rotatably mounted motor shaft connected axially to the turbine blades and extending horizontally from thebladesA through the compressor zone in the foam-producing chamber, the. shaft having an end terminating in the foam-i producing chamber adjacent to the nozzle outlet thereof,

and compressor means in the yfoam-producing chamber including a plurality of ixedly-mounted spaced blades extendingV inwardly from the compressor zone of the foamproducing chamber and additional blades mounted on the shaft of the liquid-operated motor and rotatable therewith intermediate the fixedly-rnounted blades for converting liquid and air in the foam-producing chamber into an intimately mixed and finely-divided foamV for projection through the discharge nozzle.

9. Apparatus for producing nre-extinguishing foam, comprising an intake chamber for receiving foam-forming liquid, the intake chamber having an inlet for receiving foam-forming liquid and a nozzle outlet oppositely disposed with respect to the inlet, a foam-producing chamber having on open intake end into which the nozzle outlet of the intake chamber projects, the said openv intake end of the foam-producing chamber `defining an an in advance of but adjacent to the foam-discharge nozzle,l and a liquid-actuated motor including rotary actuatingv blades positioned in the intake chamber intermediate the inlet and nozzle outlet thereof, a horizontal rotary shaft attached axially to the blades and rotated resp'onsively to rotation ofthe blades under impact of liquid projected' into the intake chamber, means for rotatably mounting the shaft, the shafty extending through the nozzle outlet of the intake chamber and terminating in an end located in the internally converging portion of the foarnzproducing chamber, rotary compressor instrumentalities mountedV on the shaft adjacent to its end, and additional compressor instrumentalities lixedly mounted on the said internally converging portion of the foam-producingchamber and coacting with the rotary compressor instrumentalities` for effecting a compressive mixing of the air and liquid in the foam-producing chamber.

l0. Apparatus for producing lire-extinguishing foam comprising an intake chamber for receiving foam-producing liquid, the intake chamber having a tubular inlet for the liquid, a jet-producing discharge nozzle for the liquid,

the intake chamber having a configuration presenting a-v zone of maximum internal diameter intermediate the inlet and the discharge nozzle, a tubu-lar foam-producing cham:-

ber in. axial alignment with the discharge nozzle ofthe' intake chamber, the foam-producing chamber having an open inlet end receiving and enclosing the discharge noz-1.

zle of the intake chamber and defining an annular air in` take space enclosing the said nozzle, the foam-producing chamber having a discharge end opposite to the open inlet end and including a foam-discharge nozzle, a liquid motor including a plurality of impeller blades mounted in the intake chamber and in the zone of maximum internal diameter for rotation under impact of foam-producing liquid entering the intake chamber, a rotatably mounted shaft connected horizontally axially to the impeller blades and terminating in an end mounted adjacent to the discharge nozzle of the foam-producing chamber, theshaft being rotated by rotation of the impeller blades responsive to impact thereon of entering foam-producing liquid, the liquid being projected as a high velocity jet discharge stream through the discharge nozzle of the intake chamber for aspirating atmospheric air into the foam-producing chamber through the open inlet end thereof responsively to venturi action created by injection of the jet discharge of the liquid from the discharge nozzle of the intake chamber, a telescopically operative sleeve valve mounted on the `foam-producing chamber for controlling admission of air into the lfoam-producing chamber, operating lever and linkage means mounted on the intake chamber and connected to the sleeve valve for advancing and retracting the sleeve valve with respect to the open inlet end of the foam-producing chamber for controlling the air intake therethrough, and compressor means in the foam-producing chamber adjacent to the discharge nozzle thereof, the compressor means including a plurality of spaced, xedlymounted compressor blades extending inwardly yfrom the foamaproducing chamber and another plurality of spaced blades rotatably carried by the sha-ft and rotating therewith intermediate the Xedly-mounted blades for enhancing production of the foam for ejection thereof through the discharge nozzle for the foam-producing chamber.

11. The apparatus as defined by `claim 9, wherein the compressor means in the foam-producing chamber include a zone of regularly decreasing internal diameter in the chamber in advance of but adjacent to the discharge nozzle lfor the chamber, both pluralities of ixedlymounted blades and rotary blades being located within the zone of decreasing internal diameter for enhancing production of foam.

References Cited in the file of this patent UNITED STATES PATENTS 2,073,204 Friedrich Mar. 9, 1937 2,089,646 Friedrich Aug. 1G, 1937 2,503,250 Eckert Apr. 11, 1950 2,532,986 Bedford et al Dec. 5, 1950 2,774,583 Haftke Dec. 18, 1956 FOREIGN PATENTS 428,103 Great Britain May 7, 1935 518,837 Belgium Apr. 15, 1953 689,818 Great Britain Apr. 8, 1953

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