US2577451A

US2577451A - Apparatus for the production of air foam and air foam fire-extinguishing installations

Info

Publication number: US2577451A
Authority: US
Inventors: Clemens Gunter; Westenfelder Egidius
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1949-02-24
Filing date: 1950-09-23
Publication date: 1951-12-04
Anticipated expiration: 1968-12-04

Description

Dec. 4, 1951 G. CLEMENS ET AL APPARATUS FOR THE PRODUCTION OF AIR FOAM AND AIR FOAM FIRE-EXTINGUISHING INSTALLATIONS 2 SHEETS-SHEET 1 Filed Sept. 25, 1950 W. WW t o o r W a Q t s a ee LC WY 0&7 Z twfiw Q... 5 umg q E H w m 3 1951 G. CLEMENS ET AL 2,577,451

APPARATUS FOR THE PRODUCTION OF AIR FOAM AND AIR FOAM FIRE-EXTINGUISHING INSTALLATIONS Filed Sept. 23, 1950 2 SHEETSSHEET 2 Patented Dec. 4, 1951 ABPARAEUSiFQErTHE PRDDUCIIONJ? FOAM AND AIR,- FOAM FlltEzExTlNGlllsfl- INGPINSTALLATIONS Gilnt'er- Clemens, Hamburg-Nienstedten,-= and E'gidiusir. Westenfelder, Germany;.='.assignors:to StanGandgOiLDeYelQm-J ment. Com-pan Elizabeth; Nit-J n Application September 23, 1950;"Seria1' No.- -18Ii,402 In Germany l ebruary zig -1949* In: stationary airrfoamafire?extinguishin installations -for.--- storage: tanks {for r inflammable liquids; the ,airnfoamahas; tmzbe introduced at the-:upper-edge of: the-..tanh. 1. Heretofore,--there-: fore; air-foam? producers;simiianrinaform-"to: air; jet pumps whichz-arewfedrwith .gthez mixture of" water and .foamvproducing agent vbyn-meansi ofhorizonaland:- vertical -liquid 1 pipe-.1ines,-: have been: mounted externally -in, the vioinity -of the upper edge of the tank.v lnithislknowmarrangea ment, however, there is a danger that-,thecairfoam producer will be-damaged in: the event "of an-explosiom of. the --tank.'-, for.- example if; the-too oi, the... tank 1 is .sblown off;- Furthermore this. method 10f Q mounting. makesr-suprvision, ofjrthe. air-.foam producer. ,very. .diffloult.

Theunderlyin problemwithwhichihe. 111356111. tion. is concerned is .to. pr.ovide... anairfoam..p11o.-- ducing apparatussimilar .in.form. to, an air jet) pump,,in which the air foam is.conveyed .under. its own pressurepover a,considerab1e distance and/or'a considerable height, and whichioonsequently may be -mounted on the ground or inthe vicinity-thereof In accordance with recent requirements the air foam has to have a ratioof water to air of from 1:5 to -1':-'10;*and in addition-possess' adequate stability; which isobtained, for example, by a good water retaining "power.- This problem-cannot be solved withthe air-foamproducers known---heretofore.-- If "an attempt ismade to convey air-foamoven-considerable-distances with the-known-apparatus; aback-pressure is set up, the-=efiect of 'which' -is that thefoam flows backwards out ofthe-air inlet openings of'the-air-jet'pump. In contradistinction to the existing prejudice -that the problem of" producing and conveying air-foam over--- con-- siderable distances by --means- -01 air -jet' pumps is insoluble; the present invention isb'ased on the observation that the problem can -be-- solved if-- the air' jet pump is f special design" 'and dimensions; In the knownair etpumpsemployed heretofore,- which: in general" operated fwith -fine atomisation of th'8*--1lqtlidl1?j8li, the"g1 -eat'er .--part": ofthe -*kinetic energy inherentiin the? llquid'jet;

foam mixing, so. that;, after. leavinggthe; foamv producer-,;- the 1 actua1'; f'oam ...j et, possesses; only a, small amount of ,kineticiener Y-r For :thiSJGaSQR such f0.am..-1z rmiuoi'ng,am aratus is.notradapted.- to. overcome. acQnsiderabIe -.back..pressure-in the supp1y .pipe-line. It is.therefore necessary tot. design, .ands-dimensionathe =foain:prodno71.ngg. an paratus so that the least possible energy 'SZJQSZT mthe. suctionx--sanctimixinegworkziofzitheieta.and so rran edrraimiBin-pumps:M 6; s ured o-con Hamburg -Fuhlsbutt'el,

2 consequently sufficient; amounts:- of J energy vare, available ,:f.or;;rconveying-;;the foam.

Iii-is; an obj ectof; the ;invention,-.- tom-provide :an. apparatus, for; the productionyof air-.foam which ismonveyed under itSisOWl'i pressure-over; a'-con-.

siderable distance andlomaszconsiderable height, comprising :a .pluralitw, of open; air .jet pumps connectedin parallel which. are fed from a com-, 1 mon foantirliql id.pipeeline, andgopen into-"a .com-; mon foam pipeeline the; j QtxIlOZZlQSi rand-mixing; tubes; of the air :jet pumps: being; designed .;and;

dimensioned :in. suchi-a'rmanner that a;jet of good.

coherencei'and.havingdittleatendencxrto scatter.- issues: from he: j t ;'nozz 1e,:-.said;.jet: *beinepnarrowlm nolos d sbib'i' mixingrtuber. pre ra ly of; cylindrical shape; whereby-t iti-is maintained overs;

azconsiderable lenethiwi hou premature sbre k:-- in p;-

When:this condition is.=sat-isfie.d, the energylost through} air suction and. foam-production work z-is reduced .to-a minimum.- 1. It: is clear that inorder-tmcarrythe. principle i of: the invention into effectgthetcrossesection of the mixing'tubemust; be in; at certain-ratio to the crossesectionq of. the jetnozzle. The :ratio of: the cross-sections;-

should beon1y;s1ightly greater than the ratio of.- water; to. air;- that is-z-tosay, asastated above, from .-.1 2.5. L to 1 10.

A.--further-objeot -oi--: the invention; is, to. provide astationary; air-foam extinguishing installation for storage tanks z-containing-inflammable 1- 1iquids,=. which: is; fed, by an; air-foamv producing apparatus of thegkindusetzforth. above, the air. foam producin wapparatus.being arranged an or close to the. aground; and 1. preferably outside the.- protection rwall, ;and .bei ng ;;connected bymeans;-

of; a.,f.0am -.a scension: pipe.;to ithezfoam inlet, into the.- tank-1 A form of the inventiomis.illustratedsbyytheg accompanying draw-ingsimwhich:

Fig.5 1gshows.=aafoamsproducingg apparatusgaccording to i. thevinvention, in leyatiom.

Fig 2i. shows ga foam. producer, according. to

Fig.1; 1 tinalongitudinah;section:,;in: the direction; ll'e lriinr-Fiei 8-5011; a flar er iscalet Figs 3 ashowss a section: ,-inthe-.- i1iection=: 11-1- 1 Fig. 4 shows an air jet pump with internal;

air supplygon aglargermscale;

Figure =5. showsdiagrammaticaliy the -;arrangemention a;foamieiitinguishinguinstallation :on .a

necting pieces 9 on the nozzle plate I of a liquid distributor 8. The liquid distributor widens conically in the direction of flow and is provided with fittings for reducing the resistance to flow, for example in the form of a cone I or streamlined body mounted in the centre of the nozzle plate I with its apex pointing against the direction of flow. The supply of water mixed with foaming agent may be connected to the flange II of the liquid distributor 8. In this case, the flange I I may be connected directly or indirectly by means of hose-pipes to a mixing piece, not shown, which in its turn has connections for the water and foaming agent pipe-lines. The flange II, however, may also be connected to the water supply, while the foaming agent enters through an inlet [2 and is distributed in a-man-v ner not shown. The connecting piece I3 is for the connection of a pressure gauge.

The air jet pumps I to 6 consist of a liquid nozzle M, which is cylindrical in its forward part. The cylindrical part of the nozzle has a cylindrical core l5, thus providing a nozzle exit of annular cross-section. This results in a low scatter effect of the liquid jet which emerges with a large surface.

As shown in Fig. 4,'the core I of the liquid nozzle I4 may be replaced by a tube I6, through which enters the air supplied from inside to the liquid jet issuing from the annular space H of the nozzle, so that intimate contact takes place between the hollow cylindrical liquid jet and the air aspirated from the outside and inside. Secured to the nozzle plate I is a tube l8 or similar suitable connecting means, carrying at its other free end a plate l9 having six boreholes in which are mounted the mixing tubes 20, carrying the air nozzles 2| projecting beyond the edge of the nozzles l4. It is essential that a separate mixing tube should be provided for each jet pump, and that the mixing tubes should run substantially parallel or converge at a slight inclination to the central axis. At their other ends, opposite to the air nozzles 2|, the mixing tubes 20 are fixed in a plate forming the bottom of a foam chamber 22, which gradually tapers to the prescribed connection width of the foam pipe-lines or pouring pipes to be connected to the flange 24. As indicated in Fig. 2, a ring 22 may also be used instead of a plate, in which case the plate I9 forms the bottom of the foam chamber. A connecting piece 25 is provided for the connection of a pressure gauge.

' Conveniently, the mixing tubes 20 are sur rounded by a conical casing 26 with line contact. This casing 26 imparts protection and adequate strength to the apparatus. Preferably, the casing 26 is constructed so that it forms at the same time the foam chamber 23.

The operative reliability of the foam producing tubes according to the invention is substantially greater than that of the known tubes, since rebounding and reversal of flow do not occur. In addition, considerable resistances in the conveying pipe-line are overcome, such as occur 'for example with inadequate'liquid pressure in consequence of the formation of excessively heavy foam.

Whereas in the known foam producers, a foam of high conveying pressure has been possible only with the use of pumps, and the extinguishing of a mineral oil tank of large diameter by means of air-foam has. heretofore been practically impossible, it is possibleby the present invention for such tanks to be rendered safe by foam-producing tubes operating without portable pumps. In addition, the foam-producing capacity, that is to say, the effective quantity of foam produced per foam-producing tube in unit time, is substantially greater than in all the systems known heretofore. In consequence of the high foam-producing capacity, the good quality of the foam and the high foam pressure, large tanks filled with mineral oil may be provided with air-foam fire-extinguishing installations and fires may thus be extinguished, since it is possible to provide the foam-producing tubes in a stationary or mobile manner on the ground and it is not necessary to mount the foam-producing tubes on the upper edge of the tank as heretofore. This affords the advantage that, for example, adequate protection may be provided for very large storage installations with a few mobile foam-producing tubes.

As follows from Fig. 5, in using the foam-producing tubes of the invention, it is'merely necessary to provide the tanks with an extinguishing pipe network 21 with rising pipes 28, which lead to the upper part of the tank 29. The connecting points 30 for the foam-producing tubes may be provided in a readily accessible manner close to the ground and outside the protection wall 3|. This arrangement permits of the connection of portable foam-producing tubes at the necessary connecting points in each case.

We claim:

' 1. Apparatus for the production of air-foam, comprising an elongated foam delivery chamber having a discharge end and an inlet end, a foam mixing tube extended into said chamber toward the discharge end thereof, terminating in longitudinally spaced relation thereto, injector means for introducing foam forming liquid into said tube as an annular stream of such liquid, means for admitting air into said tube as a flowing stream in intimate surface contact with said annular stream of liquid, and conduit means for supplying foam forming liquid to said injector means.

2. Apparatus according to claim 1, in which said injector means comprises a jet nozzle member having a discharge end and a coaxial core element interiorly of said end, said element in radially spaced relation to said nozzle forming an annular discharge passageway.

3. An apparatus according to claim 2, in which said core element is a solid cylindrical element.

4. An apparatus according to claim 2, in which said core element is a hollow tubular pipe element opening at one end through the nozzle discharge end, the other end of said element opening outwardly through a side wall of said nozzle.

5. Apparatus for the production of air foam, comprising a foam chamber, having inlet and outlet ends respectively, a plurality of foam mixing tubes, each having an inlet end and a discharge end, extended into said chamber through the chamber inlet and disposed axiallythereof in circularly spaced relationone to another,--ex-- tending in the direction of the chamber outlet,

withthe discharge ends terminating interiorly of the chamber in substantially equidistant spaced relationv to the outlet end thereof and the inlet ends opening outwardly therefrom, and conduit means for injecting foam-forming liquids into the inlet end of each foam-mixing tube as a jetted annular stream of such liquids and so as to inspirate air through said mixing tube inlet ends. I I 6; An apparatus-according to claim 5, in which said foam-forming chamber comprises an elongated casing member having a foam outlet end and a closure member for the opposite end of said casing and chamber, said member providing support means for the mixing tubes extended into said chamber.

7. An apparatus according to claim 5, in which said axially disposed mixing tubes extend in substantially parallel relation to each other and to the principal axis of said chamber through the outlet thereof.

8. An apparatus according to claim 5, in which said axially disposed mixing tubes extend longitudinally of said chamber in converging substantially uniformly angular relation to the principal axis of said chamber through the outlet thereof.

9. An apparatus according to claim 5, in which said conduit means for injecting foam-forming liquids into the inlet end of each foam mixing tube, comprises a conduit distributor element having an inlet portion, and an outlet end portion extended toward and terminating in spaced relation to the inlet ends of said mixing tubes, and a plurality of jet nozzle elements for discharge of said liquids, each having an inlet end communicating with said distributor element and a discharge end extended into the inlet end of a mixing tube in radially spaced relation to said tube.

10. An apparatus according to claim 9, in which said distributor element comprises a hollow, frusto-conical member having an inlet at the apex end thereof and an open base end portion. a closure plate for said base end portion, and a plurality of tubular conduit members supported by and opening through said closure, each of said members adapted to receive and communicate with a jet nozzle element for discharge of foam-forming liquids therethrough.

11. An apparatus according to claim 9, in which said distributor element comprises a conduit member flared outwardly in the direction of said mixing tube inlets providing a chambered portion in said member.

12. An apparatus according to claim '10 including a flow deflector internally of said distributor element and comprising a conical member secured to said closure plate by its base end and concentrically therewith, the apex end of said member extending in the direction of the inlet to said distributor element.

13. Apparatus for the production of air-foam which comprises the combination of a casing defining a foam chamber, said casing having opposite inlet and outlet portions, a closure for the inlet end portion of said casing, said closure provided with a plurality of radially disposed, circumferentially spaced passageways opening therethrough into said casing, a plurality of foam-mixing tubes extended through said passageways into the casing and chamber, said tubes each having an inlet end opening exteriorly of the casing and discharge end opening into the casing and chamber, said tubes supported within said casing in spaced relation to one another circumferentially of the chamber, and arranged therein with the axis of each tube in substantially equidistant radial relation to the axis of said casing, and means for supplying foam-forming liquids and air to said mixing tubes, comprising conduit means for conveying said liquid, a liquid distributor member communicating with said conduit means at one end and flared outwardly therefrom toward the inlet end of said casing, a plurality of jet nozzle elements opening from said distributor member and extending therefrom into the inlet ends of said mixing tubes in coaxial radially spaced relation thereto, and a concentric core element internally of each jet nozzle providing for the discharge of an annular liquid stream therefrom.

GUN'I'ER. CLEMENS.

EGIDIUS WESTENFELDER.

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

UNITED STATES PATENTS Number Name Date 1,629,027 Erwin May 17, 1927 2,073,204 Friedrich Mar. 9, 1937 2,164,153 Friedrich June 27, 1939 2,423,618 Ratzer July 18, 1947