US2502143A - Fire-extinguishing method - Google Patents

Description

March 28, 1950 c. A. GETz 2,502,143

FIRE EXTINGU-ISHING METHOD Filed Aug. so, 1944 10 sheets-sheet 1 March 28, 1950 c. A. GETz 2,502,143

, FIRE EXTINGUISHING METHOD Filed Aug. 50, 1944 10 Sheets-Sheet 2 azflesl 'ez March 28, 1950 Filed Aug. 50, 1944 c. A. GE-rz 2,502,143

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I FIRE EXTINGUISHING METHOD Filed Aug. 50, 1944 v10 Sheets-Sheet 6 March 28, 1950 c. A. GETz 2,502,143

FIRE EXTINGUISHING METHGD Filed Aug. 30, 1944 10 Sheets-Sheet '7 Jgd March 2.8, 1950 c. A. GETz 2,502,143

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M. Emu w Patented Mar. 28, 1950 FIRE-EXTINGUISHING METHOD Charles A. Getz, Glen Ellyn, lll., assigner, by' mesne assignments, to Cardox Corporation, Chicago, Ill., a corporation '0f Illinois Application August 3), 1944, Serial `No. 551,869

' 26 anims. (C1. 16e- 11) This invention relates to new and useful improvements in methods for extinguishing res. This application is. va continuation-in-.par.i'l of my ycopending application Ser. No. 502,175, led Septomber 13, 1943, now abandoned.

Patent No. 2,352,399, issued to Leonard D. Myers on June 27, 1944, broadly covers the development of combining pre-formed water fog with carbon dioxide snow and vapor to provide an extinguishing medium discharge that possesses very marked improvements in carrying range and penetrating capacity, as Well as ability to more quickly extinguish res and cool the material being consumed, .as well as associated heat absorbing masses, to a temperature below that at which the combustible materials will rekindle or reash.

The specific apparatus that is disclosed in the above identiiied patent produces a combined discharge stream of carbon dioxide and water fog. The carbon dioxide of the discharge consists. of snow and vapor components which are separated or .segregated to provide a snow core and a vapor enclosing or encircling envelope. The water fog is completely formed or generatedv before it is combined with the carbon dioxide. The water fog generating device is so constructed and arranged that the. angle of' projection of the .fog causes complete entrainment of all of the Water droplets in 'the carbon dioxide. The combining of the carbon .dioxide and water fogmay be .such

that the water droplets are entrained by both the snow core and the vapor envelope, or so that all of the water droplets are entrained by the vapor envelope. Because of this complete entrainmentv of the water fog by the carbon dioxide, the amount of water fog that is delivered. to the scene of the lire is `limited tothe entrainment capacity of the components of the carbon dioxide discharge to which the water droplets are delivered. That is to say, a greater volume of water fog can be delivered to the nre zone when the water droplets are entrained .by both the snow and the vapor of the carbon vdioxide discharge than when water droplets are only entra-ined by the vapor.

It has been determinedthat the combined carbon dioxide and water fog discharge .of the aforesaid patent lis only slightly more effective for .extinguishing Class A res-res involvingv ordinary combustible materials, suchv as paper,

wood, etc.when water fog vis entrained by both 'the `snow and the vapor `than when water ,fog is Lonlytentrained bythe vapor, notwithstanding the facltthatjtwce the volume of water fog maybe 55 delivered to the scene of `the re when both tne snow and the vapor are employed as carriers. This peculiarity was assumed to be due to thefact that Class A res 'are most effectively extinguished by a medium which 'both quenches and cools; that all of the water droplets that are entrained by the carbon dioxide snow are converted to water ice ,particles and for. that reason aii'ord very little immediate quenching action; and that substantially all `of the quenching action of the entire discharge is accomplished by the water droplets that are entrained by the carbon dioxide vapor which converts only a portion of the droplets to water ice.

It was discovered that the high velocity of the carbon dioxide discharge lproduces suilcient suction or aspirating Vaction to create an air current or iiow adiacent the periphery of and in the same direction asv the carbon dioxide stream and that this fluid moving force or reaction could be relied upon rto carryto the re zone Water .fog or water fog foam that is projected in a certain relation with respect to the periphery of the carbon dioxide stream.` This discovery led to the clevelopment of the structural arrangement. of the extinguisher discharge `apparatus shown in the drawings of the present application, wherein the vgenerated Water fog or vwater fog foam `is projected vin such a manner that approximately one-.half of it is actually er1-trained by the vapor envelope of the carbon dioxide discharge while. the remainder is carried along to the `'lre zone by the aspirating action of the carbon dioxide stream.

Class B fires-fires involving flammable liquids, grease's, etcare most effectively extinguished'by amedium which cools and smothers.

Carbon dioxide is an excellent extinguishing agent for this class of fires, including uids of both high and low volatility,r because of its high cooling capacity and its 4ability to form a smotherin-g and fuel diluting'blanket over the surface of the liquid. The single'weakness of carbon dioxide for extinguishing iires of this classis that the carbon dioxide -bianket -dissipates rather rapidly and consequently fails to lprovide 'a relatively parma* nent protective blanket over thesurface of the flammable liquid. ,`The provision of such a permanent blanket is very important and highly desirable when the hazard involved includes spilled gasoline,or thelike, because the relatively Vpermanent blanket provides Aprotection against reignition caused by accidentally ..created sparks, or the like.

Foam extinguishers are effective. for Class B fires because of their extremely effective .and

permanent smothering characteristics. However, they are rather slow in their action, due to the necessity of gradually building up the blanket formation over the surface of the involved body oi liquid. Their use is generally limited to the treatment of horizontal surfaces.

Water fog of the low-velocity variety depends primarily on cooling and diluting for its fire extinguishing action. Its range of application is limited because the Water droplets are very small and necessarily have a low discharge velocity. Water fog is of distinct value in ghting res involving the less volatile flammable fluids, such as fuel oil, but it has very definite limitations with reference to its use on the highly volatile liquids. For instance, burning gasoline flowing over a pavement can rarely be extinguished by water fog, although gasoline fires in open tanks, having a substantial amount of free-board, can some times be extinguished by directing the fog against the free-board if the latter is hot enough to convert the fog to steam.

Class C iires--fires involving electrical equipment-require a non-conducting extinguishing agent. Carbon dioxide undoubtedly is the best all-round extinguisher for this class of fires because of its non-damaging characteristics. However, electrical equipment that involves a substantial amount of insulation material that can smolder can only be extinguished with carbon dioxide by a prolonged application of the same.

Low-velocity water fog can be employed on electrical equipment res because the ne droplets oier an enormous resistance to the flow of electricity and the quenching action of the Water is very effective in extinguishing smoldering insulating material. However, complete extinguishment of electrical equipment fires by means of water in any form causes substantial property damage.

The use of foam on Class C i-lres is never recommended unless no other, more suitable extinguishing agent is available because of the high property damage that results and because foam is highly conductive of electricity.

From the aboveanalysis of the different classes of res and the effectiveness, or lack oi effectiveness, of carbon dioxide, water fog, and foam as extinguishing agents therefor, it will be seen that no one of these agents is an all purpose extinguisher. It is because of that fact that city re departments and the fire fighting organizations of large manufacturing plants, or the like, must be provided with diierent pieces of equipment for handling the different types of extinguishing agents that are required to combat all of the classes of res such departments and organizations may be called upon to handle.

The primary object lof the invention is the provision of methods of eiecting quick and cornplete extinguishment of different classes of fires and of preventing reashes by combined and/or separate applications of carbon dioxide and water fog foam, mechanical foam, chemical foam, or mechanical-chemical foam.

Another specic object of the invention is to provide methods of effecting the extinguishment of res by means of a discharge stream consisting of a core of carbon dioxide snow, an encircling layer or envelope made. up of a mixture of carbon dioxide vapor and pre-formed water fog foam, and an external layer or envelope of water fog foam.

A further object of the invention is to provide a method of effecting extinguishment by :first attacking the fire with a combined discharge of carbon dioxide and pre-formed Water fog foam to quickly dispose of the ame and partially cool down the burnt material and associated heat absorbing masses, and by nally applying to the surfaces of the burnt material and heat absorbing masses a cooling and smothering blanket formed of Water fog foam to prevent reflash.

A still further obj ect of the invention is to provide methods which are capable of effecting the extinguishment of diierent classes of iires as a result of the direct application of carbon dioxide and foam separately, or as a combination of carbon dioxide and foam.

Another object of the invention is to provide a method of effecting extinguishment by iirst attacking a fire with a combined discharge of carbon dioxide and foam; the foam being either of the water fog, mechanical, chemical, or mechanical-chemical type; to quickly dispose of the ame, cool down the burnt material and associated heat absorbing masses, and build up a thin smothering blanket of foam, and by nally completing the building up of a heavy smothering blanket of foam to prevent reash.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specication and in which like numerals are employed to designate like parts throughout the same,

Figure l is a diagrammatic View of the fire extinguishing apparatus embodying this invention,

Figure 2 is a front elevational view of the discharge apparatus for the iire extinguishing agents that are made available by the apparatus of Fig. 1,

Figure 3 is a sectional view taken on line 3-3 of Fig. 2,

Figure 4 is a diagrammatic view of the discharge apparatus of Figs. 2 and 3 and illustrates the projection angles, etc., of the carbon dioxide and the water fog or water fog foam discharges,

Figure 5 provides a diagram of the discharge pattern taken on line a-a of Fig. 4,

Figure 6 is an elevational View of a water carbonating tank which may be substituted for the water tank of Fig. 1,

Figure 7 is a similar View to Fig. l but illustrates apparatus for producing chemical foam for use with the carbon dioxide,

Figure 8 is a similar View to Figs. l and 7 but illustrates slightly diiierent apparatus for producing chemical foam for use with the carbon dioxide,

Figure 9 is a front elevational view oi the discharge apparatus for the i-lre extinguishing agents that are made available by the apparatus of Figs. 6, '7 and 8,

Figure 10 is a sectional view taken on line IU-IU of Fig. 9, Y

Figure 1l is a front elevational view of the discharge apparatus for the re extinguishing agents that are made available by the apparatus of Figs. l, 6, 7 and 8, and

Figure 12 is a sectional View taken on line |2-I2 of Fig. 11.

In the drawings, wherein for the purpose of illustration are shown the preferred embodiments of this invention, and rst particularly referring to Fig. l, the reference character 6 designates in its entirety the insulated storage tank for liquid carbon dioxide. This liquid, preferably; is main- A.5 tained at a `desiredesubatmospheric temperature, and its correspondingfloW-vapor pressuraiby the rcoolingcoil 'I -lwhichfs included as apartmf a vmechanical `refrigerating cycle. :Although vthe .liquidfcarbon diox-ide'used for .carrying-out this :invention is imorefeftlcient and-effective Wheniit iisuat apreselected low temperatura-and itscor- `:responding low vapor pressureitisto be under- .stoodlthat `.the inventioncontem-plates the uselof high pressure .liquid carbony dioxide .stored .in '.a .bank of ,pressure cylinders.

Liquid carbon ^dioxide is -Withdrawn yfrom .the insulated storagetank 6 through the pipe line a8 ...thateextends-to Vthe carbon dioxide dischargeipor- :tion -9 Y of the Y discharge .apparatus l:or nozzle.

control valve I is illustrated as being lprovided Adnt-this `^carbon f dioxide pipe line .8 adjacent .the storage tank's. This valye.isremployed;for con- .trolling the flow of liquid carbon .dioxide (from @the tank to ythe nozzle portion 9. 7The valve .I9 .may be :either manually or rautomatically `opereatedg-as desired. z'I-he2pipe line 8 may be A.of A.a .rigid-.character if .thea'pparatus of Fig. .1.is.em- Lployedwas a xed reextinguishing system or .if .thefentire apparatus is associatedwith'mobile fire :lighting apparatus of the typekdisclosed .in `the .EricfGeer.tz patent, -No..-2,352,3'79, issued .June..27, 12119.44. `EIhispipe line.8,.also,.may take `the :form of a flexible hose line if desired. Ii a exible. hose '.-line .is 4employed, afsecond :control .valve should :be;.provided. in Vclose proximity to 5 the .carbon .dicxidedischarge Lportion `:9 -zof the nozzle, 4in .ac- .cordance With-.the disclosures of .the patent ,to eHilding N. -.Williamson, for Jlire extinguishing discharge apparatus, No. 2,354,631, -issued July 'i2-5, .194.4.

`.The i. discharge vnozzle or aapparatus, designated Linits entirety by the reference character I I .also iincludes a lwater -fog .and Vwaterog `foamgenferating nozzle portion A4I2 which is associated with :the fperiphery of the carbon dioxide v-disicharge inozzle Iportion `9. .A pipe .line lf3, -fwhich .may either :be -rigid Yor flexible, depending upon -zthe character ofthe carbondioxide .pipe..1iner8, eis suitably Tattached y at .its outer .end to .the genl.er-ating nozzle portion I2 and .extendsrsalon'g a suitable part of'the pipeline E8 :to -beattached @thereto 4Icy/clamps, bands,.or :the `like .M. If .the ,,pipe-1ine.8 takes the :form y.of Wra sflexible `.hose fline and .is provided *with a .valve adjacent uthe disfchargeinozzle IfI ,-the;pipe .line 43, alsopshould be xexibleand .it should be provided with .a flow control 4Valve adjacent .the .discharge nozzle yI I. -The Water pipe line -I.3 eisaintendedtobefused .ras a premixingchamber .for water :and a fnam fstabilizing .chemical 4`and .=is connected vto the Lbranch..lines #5a anddb fortthatfpurpose. .The .ibranch line -I5aisconnected to the waterxsupply pipe I6 that is in turn connected nto the water .storage ytank.l1. `A,-suitableeontrol.yalvesl is .located in the .water supply `l.pipe I6 Iand -is employed for controlling .and regulating the `.rate'of fflowof water. Theibranch .line I5b isconnected .to the `supply tank .I9 .fior thefoam :stabilizing fzchemical. Y Although the vwater y.can be yWtihdrawn Afrom @the tank r:Hand propelledtothegenerating nozv.zle .portion .or v.ring .L2 vby:mea1'1s`of.a `suitable electric motor or i gasoline Yengine .driven pump, Pnot. shown,..it. ispreferred .insofar as thisinvention isconcernedto .expel the `Waterfront the storage f tank by incansofcar.hon .dioxide .vapor .pressure -obtainedfrfom:the insulated carbon dioxide stor- .sageitanke I'Fhis vaporpressure is -tobtainedfby nthe :pipe -line that .extends ifrom r.the vapor yspaceftof .the .carbon dioxide storagextank 16 tto' .theetopaof .the watery-storage tank rt'I. fha-suit- A.able .'flow controlling and pressure regulating Avalve 20a iis provided in `the 4fp-ipe line '20. Although a 'vapor `pressure `of lapproximately 90 ypounds -per square inch can `be z employed `fort .ex-

pelling :the Waterffrom Ithe .-tankll, it-has been .determined .that foggingofthe water-'bythe generating ring -IZ is more efficient whenpressures from ,125 `-pounds to approximately "20G pounds, ,per. square inch, are employed.

The tfoam stabilizing chemical supply Vtank `I.9 is provided with aremovablecap I`9a, for closing .an opening `through-umich -the chemical risin- Ltroduced and va second lcap IzSb `for closing an Iopening through which-the tankfmay be drained .and flushed out. A ,branch-line 12 I :receives IWa- .ter'from the vsupifzlyppe I6 andidelivers ittothe .top of fthe chemical supply tank:l9. Thiswater enters the tank and` forces thefoam stabilizing `chemical out of the tankthroughits-bottom con- 1nectionzyvtihthe branchline |519. A .valvefZZis connected in thebranch line Ib for'regulating therate at which the` chemical .isdischarged from vtank I9. .In this way, `tlie;amount of chemical Aflowing through branch .line I5?) into 'the pipe -line 23 as `compared to the amount of Water now-- ing through branch vline [5a into `thepipe line I3 can be regulatedand controlled to obtain the desired proportions. Valve 2'3 Eis :connected in r-branch line .12! topermit .thechemical tank i9 '.tobe completely cut oifrolm pipe lines I3 andelx forfilling andcleaning purposes.

.The foam stabilizingchemical placedxin tank .I9 can `be .any of the Well 'known stabilizing lagents, such .as an aqueousi solution .of saponin, secondary extract of licorice, leguminous extra-ct, extractfoftanbark, or the like. When l.the apparatus .is :subjected to :freezing temperatures, ta Q suitable 'anti-freeze solution, .such as calcium lchloride, is ladded. This foam stabilizer can `be 'mixed with `water during the ow of the latter through thexpipejlineLISand-no foaming will occur'until the mixture isldischarged. If desired, the 'foam :stabilizer-'can bei premixed'with-,thewww .terintank I' andthe chemical supply tank I9, lwith its piping, dispensed with.

Because of my desire .to be/able .togenerate seither v`Water'og or Water :fog foam vsit-selected intervalsvby means .of thev generating; nozzle `ring IL/Iman controldeli-very of the foaming chem- .icaltozthe'waterxilowpipe line i3 by means of val-vies z2f21'and v23.

.The construction of the-'dischargeapparatus or 1.55 :nozzle I-'Zzs best disclosed'linligs. Zand 3 and .Will -he described lin detail kin connection `with rthesefgures.

v.The carbon dioxide :discharge vportion fS rdf .the-.complete nozzleis of the type disclosedand (iO rbroaclly claimed in thegpatentto I-Iilding-VJWiln lliamson, .N0. 2,351,089, issued August 29, "1944.

.Thelliquid carbon dioxidesupply pipe line-T8 :suitably A'threadedly connected `to the :stem `or shank24 ofthe .carbon dioxide nozzle portion *.05 :9. This stem'or-shank'ill is provided vWith-a kbore25=for deliveringlthe liquid carbonfdioxide :toxtherinterior of thebodyfportion of thenozzle.

The :outer or-forward end 2610i this bore communicates lwith Lthe interior l of "a 'deflector ele- J0 4ment and wcooperates 'fWt-h thisv elementJ tcform aflow path forithediquidicarbonfdioxide. The

:stem orshank 24 'has formed von its outer end .a zradially texten-ding 'iange r=2l 'which `is :formed :with faxcircular: :series oirorices Zilthroug'hfwhich ..75 :thesliquid carbon` dioxide is ,frei-eased ":to mpermit 77 sudden expansion so that its pressure will drop below '75 pounds per square inch, absolute, which will cause a certain percentage of the liquid to ash to snow while the remainder of the liquid 'is vaporized. This annular flange 2l' is further 'provided with a circular series of threaded openings 26, for a purpose to lbe explained at a later point. Exteriorly, the stem or shank 24 is provided with a rearwardly curved or flared surface 30 that terminates in a shoulder 3l.

The deflector element referred to above is identied by the reference character 32 in Figs. 2 and 3. This defiector element is secured to the fiange 2l by means of the series of screws 33 that are threaded into the holes 29 of the flange 2. The deector is partially hollowed out so as to control the direction of flow of the liquid carbon dioxide to the discharge orifices 28. For this purpose, the interior of the deflector is provided with a conically shaped projection 34 that is axially aligned with the bore 25 of the shank or stem 24. The interior of the defiector element 32, radially outwardly of the spreading projection 34, is provided with the curved surfaces 35 that function to change the direction of ow of the liquid carbon dioxide so that it will be directed rearwardly through the discharge orices 28. The inner or rear portion of the defiector element 32 is belled or curved outwardly at 35 to form an internal curved surface 31 that lies opposite to and cooperates with the curved exterior' surface 30 of the stem or shank 24. Fig. 3 clearly shows that these two cooperating surfaces 3l] and 31 diverge with respect to each other in any radial section to form an annular passageway that gradually increases in depth or thickness. This increase functions to permit further expansion of the released carbon dioxide so that the pressure of the same will drop still further and will provide for ashing of whatever liquid may remain as a part of the flowing material. The outer portion of the deflector element 32 is illustrated in Figs. 2 and 3 as being formed with radial ribs 38 which form the valleys 39 having curved inner surfaces 40 Which will function to deflect forwardly or axially any of the discharged medium that comes in contact with the same.

The defiector element 32 and the cooperating portion of the stem or shank 24 are enclosed within a chambered body or casing which is formed by the inner portion 4l and the outer portion 42. The inner portion 4l of the body or casing is dish shaped and is centrally cut away at 43 to permit the inner portion of the stem or shank 24 to pass therethrough so that the shoulder 3| of the said stem or shank will act as a seat or an abutment for this inner portion 4I of the body or casing. Any suitable means may be provided for securing the body or casing portion 4l to the shoulder portion 3l, such as by welding or by theuse of suitable screws or bolts. The outer portion 42 of the body or casing is of cylindrical shape and has its inner edge portion overlapped or telescopically associated with the outer marginal edge portion of the inner body part 4I to provide a lapped joint 44. Welding, or the like, may be employed for rendering this joint permanent. Figs. 2 and 3 clearly show that the body or casing of the carbon dioxide discharge nozzle portion cooperates with the stem or shank 24 to provide a, closed rear Wall while leaving the front of the apparatus entirely open. The body or casing additionally cooperates with the stem or shank 24 and the deflector element 32 to form an annular and vapor.

8 chamber for receiving the circular series of flow controlling and directing units 45.

yThese units 45 are equally spaced around and extend radially of the stem or shank 24 and the deflector element 32. Each one of these units includes a semi-circular or semi-cylindrical band 46 which is flanged at both of its longitudinal edges 41, see Fig. 3. The inner transverse edge 48 of each one of these bands 46 is suitably anchored either in close proximity to or in contact with the periphery of the ilared portion or surface 30 of the stem or shank 24. The outer edge 49 of each one of these bands 46 terminates in the plane of the outer face of the body or casing portion 42 and the outer edges of the defiector element ribs 38.

The opposite sides of each one of these flow controlling and directing units 45 are formed by wall members 50 which lie inside of the edge flanges 41 and are suitably secured thereto. These Figs. 2 and 3 show the opposite side walls of each adjacent pair of units 45 as being formed by a single piece of sheet material with the center or intermediate portion of each one of these side Wall forming pieces designated by the reference character 5|. These center or intermediate portions 5I function to bridge the gaps or spaces left between the inner edges or sides of adjacent units 45.

Fig. 3 clearly discloses the side walls 5D of the several units 45 as having apertures 52 formed therein. These apertures are formed in the outer or vfront halves of the side walls 56; i. e., relatively close tothe outer edges 49 of the bands 46. Each flow controlling and deflecting unit 45 has mounted within the same a plow-shaped deecting and separating element 53. These elements are of V or wedge shape in section with securing anges 54 formed on the sides thereof for securing, such as by welding, the elements 53 in their proper places within the units 45. Fig. 3 discloses these deecting and separating elements 53 as being arranged with respect to the side wall openings or apertures 52 so that the lateral sloping surfaces 55 of each element will split or spread any material iiowing through the interior of a unit 45 so that this material will be deflected through the cooperating side Wall openings or apertures 52. These elements 53 are shown in Fig. 3 as being arranged so that their outer transverse edges 56 are spaced from the inner surfaces of the outer end portions of their associated bands 46. In other words, a space or gap is left between the inner surface of the hand 46 of each one of the units 45 and the outer edge 56 of its associated deflecting and separating element 53 through which the extinguishing medium may flow to the outer edge 49 of the band 46.

The mode of operation of the carbon dioxide discharge nozzle porion described above is expained in detail in the aforesaid Hilding C. Williamson patent and for that reason its mode of operation will be more generally set forth herein. Liquid carbon dioxide, at any desired pressure and temperature, will be delivered to the bore of the shank or stem 24 and will ow as a liquid to the discharge orifices 28. As the liquid carbon dioxide leaves these orices, it expands suddenly and its pressure drops to such an extent that the liquid flashes and vaporizes. The carbon dioxide that enters the space formed between the outwardly iiared surfaces 3D and 31, therefore, takes the form of a mixture of snow Depending upon the temperature of the liquid rcarbon dioxide :that is delivered `to this discharge apparatus, va :certainpercentage lof the same willash intosnow as 'a result of the self-'ccoling'action that is produced. In other words, the entire discharge from the peripheral mouth, formed -by the outer* edges ofthe surfaces 30 and 3'1, will consist of a mixture of snow and'vapor.,

This snow andvapor mixture, as` it leaves Ithe aforesaid peripheral mouth, will be flowing in a `truly-radial direction. Some portions of the mixture will pass directly into the various flow con "trolling and directing units 45. .The remainder ofthe mixture will besplit and deflected laterally in opposite directions by the axially extending rportion of; theside Wall formingpieces '50. These deflected portions ofthe mixture, therefore, will be directed into the several units 4,5.

`The outer lcurved bands '46 ,of the ilow controlling and directing lunits 45 will deilect the flowing mixture from its. straight line, radial path and-convertthe straight line flow ofthe vsame into a curvilinear'iiow or motion. vAs the carbon dioxide snow of the mixture isy many Vtimes more. dense than the carbon dioxide vapor, and as the velocity of both of these components is the same, -'the snow oifersmore resistance to the deiiecting force exerted by the obstructing, curved bands 46 with ,the result that the snow will be moved tothe outer side o f each one of the curvilinear ilow paths-for the material, The snow, in seeking this Vouter portion oi each flow path, will crowd or force'the vvapor inwardly away from the inner surfaces ofthe various bands 4.6. The difference indensity of the snow, as compared to the vapor, therefore, effects a. segregation of these two components. The snow is segregated at or close tothe outer side of each one of the curvilinear paths while the. vapor is segregated onthe inner'sideof each path.

Asy the segregated snow and-vapor reach the outer side of each'one `of the flow. controlling anddirectingunits 45, the'snow passes through the gap or space left between "the inner surface of its band 4'5 andthe cuter edgeo itsflow splitting and separating element 5-3. The inwardly positioned, segregated vaporfhowever, strikes the sloping surfaces "55 of the various elements 53 'and is directed laterally lthrough the side wall apertures 52 into the portions of the body or casingwhich liebetween adjacent units 45. The segregated and separated snow passes radially outwardly beyond the edges 49 of the several Ibands 45 and is `directed into the Valleys 39 ofthe delector element 32. The curved inner surfaces 4G of these valleys deflect the snow so that it will iiow, or'will be discharged, to the atmosphere in an axial direction'with respect'to the entire carbon dioxide discharging apparatus. This discharge of all of the separated'snow from all of the units 45 causes the-samel to be assembled `into a compact, dense vcore for the entire vcarbon dioxide discharge. The separated `vapor will leave the-spaces between the adjacent units 4.5 .and will flow in an axial' direction relative to .the discharge apparatus. The vapor is in this .way disclfiarged outwardly of the 'dense `snow core. Because the areas of discharge for the vapor are spacedLdis-tances equal to the width of the flow controlling andy directing units '45,

`the vapor discharges will be separated lfrom each y other immediately adjacentthelfront face of" the apparatus. However', the vapor discharges will blend together ashort distance inadvance ci the apparatus, and'wil'lV form-i a. surrounding or= enclosv units 45.

l0 `ing vaporenvelope for the compact, dense snow vwhich forms thel core of the composite discharge. From 'this description of the mode of -opera- 'tionfof the'discharge apparatus for the carbon dioxide, itwillbe appreciated that there is :Oro-` -vided a discharge stream which is of` substantially circular shapein transverse section. In Fig. l3` ofthe drawings, the dotted lines A and -B are intended 4*to represent the peripheral marginof this compositestream on the section of this-iigure. The dotted lines C and D are intended to illustrate the peripheral margin of the compact, Adense snow core. Therefore, the inner and outer marginsfof the vapor envelope are represented by theI dotted lines A-C and B-D.

"The wateriog and water fog foam generating portion #|12 oi theentire discharge nozzle or apparatus consists of the hollow water ring 51 'that surrounds the outer edge portion-of the body creasing part'i42. -Anysuitable means maybe employed fior properly attaching this water ring to .the body creasing and a band of any -suitableheatinsul-ating material of any proper thickness may be-provided at 58 to insulate the water in'theiinterioroi the ring from the low temperature of therbody or casingpart 42. -Waterby itself or mixed withthe foam stabilizing chemical is supplied to the interior ofthe ring bythe pipe line i3"through the suitableconnection. The ring I5'! is'provided witha iront wallSll that iseforrned with v.the two annular, angularly arranged portions iil' .andiiz :Each one of these iront; Wall'porticnsczis` provided with an annular series of apertures l'whichmay be of .any-size. or diameter desired.. The apertures lfory the lfront ywall portionv 6l' are designated by the reference character 63 whileztherapertures,for the wall'portion Glare designated by the reference characterfd. yEach-one'o'f the apertures-53 is arranged in thessameradial plane as anaperture .64:so that =the :axes .of the several apertures 1(i3 are angular-ly arranged with respect :to the axes of the apertures: 64. These y axes'. `are designated'by the referencefcharacters E and -E respectively. By inspectingfFig. 2, it will be seen-that thefasso' elated-.pairs of aperturest andMare radially aligned withA the carbon dioxide vapor discharging spaces that .are located -between adjacent carbon Idioxide flow `controlling and directing Asa-solid stream of water or water :mixed with a foam stabilizer will befdischargedthrough each one of these apertures 6.3:'andf'4', thestreams foreach associatedyradially aligned pair of apertures, .will impinge against: each other with `the resul-t that Ithe water orfwa'ter and roam stabilizer mixture- ".ot both streams will line/broken up intoaiog or a-fog foam which is` formedof very ne waterdroplets or foam bubbles ioi uniform size.. This water iogor water Vfog foam will iill to a substantially yuniform Ydensity-all portions of the space ,lying between theangularly arranged axeslines E and .F outwardly of the Ypoint or zone of impingement of the two streams.

Lety us now consider the diagrammatic disclosures of'Figs. '4 and 5 in connection with the disclosure of' Fig. 3*.V Figs. 4 and 5 have applied thereto the reference characters A andB which designatethe louter limits ofl the carbon dioxide discharge stream, and, of course, the outer limits ofthe carbondioxide vapor envelope. The reference/characters C" and D are appli-ed to Figs. 4 and iso-designate the outerl'imits ofthe carbon .dioxide snow core and the inner limits of the :associated fog generating apertures 63 and 64.

Fig. discloses the dotted lines of Figs. 3 and 4 translated into circles to illustrate the type of pattern provided by the discharges of carbon -dioxide and water fog or water fog foam atY the transverse plane that is represented by the line a--a of Fig. 4.

If We consider that the carbon dioxide is being .discharged all by itself, the margins of the carbon dioxide stream will be represented by the circle A-B of Fig. 5. The circle C--D of this iigure represents the outer margin of the snow .core and the inner margin of the vapor envelope. If we now consider that the generating nozzle portion l2 is discharging all by itself; i. e., without any carbon dioxide discharge taking place, the outer ring F of Fig. 5 designates the outer projection margin of the Water fog or water fog foam pattern on plane a-a. The center dot E of Fig. 5 indicates where the inner projected margins` of the water fog or water fog foam discharges intersect. These inner margins are represented by the dotted lines E of Fig. 4.

Let us now consider that we have a composite discharge of carbon dioxide and water fog or water fog foam. It has been determined that .the high velocity of discharge of the carbon dioxide vapor, which occurs between the lines or circles A-C and B-D, deiiects and entrains the portion of the water fog or water fog foam discharge that overlaps or coincides with the carbon dioxide discharge with the result that the water fog or water fog foam does not penetrate the carbon dioxide stream beyond the inner margin C-D of the carbon dioxide vapor. The deected line G, therefore, is employed to designate the new inner margin of the water fog or Awater fog foam. y

In the introductory portion of this specication, it has been stated that the aspirating action of the carbon dioxide discharge stream will function to carry with the stream, in a zone surrounding and encircling the carbon dioxide stream, the ne droplets of the water fog or the fine bubbles of the water fog foam that are properly associated with the periphery of the carbon dioxide stream. This aspirating action produced by the carbon dioxide stream, therefore, causes the outer margin F-F of the water fog or water fog foam discharge to be drawn in to parallelism with the outer margin A-B of the carbon dioxide stream. This defiection of the outer margin of the water fog or water fog foam discharge is represented by the lines H. These lines are curved in Fig. 4 axially of the composite discharge and take the form of aV circle in Fig. 5. The water fog or water fog yfoam lying between the circles VH--I-I and A-B of the pattern disclosure of Fig. 5 will be carried along the scene or zone of the re by the aspirating action of' the carbon dioxide stream. Of course, this inward deflection of the water fog or water fog foam discharge is accompanied by entrainment of some of the fog or fog foam by the carbon dioxide vapor portion of the composite discharge. Such peripheral entrainment by the carbon dioxide discharge stream is a normal, inherent function and it will be noted that if water fog or water fog foam were not being generated, the carbon dioxide stream would en train air at its periphery.

It is believed that persons familiar with the art of producing and using foams for extinguishing lires will fully understand what is meant by the term water fog foam as applied to the type of foam that is produced by the apparatus so far described. Nevertheless the following explanation will be given so that no misunderstanding will be possible. Y

There are two Well recognized types of fire extinguishing foams; i. e., mechanical air foam and chemical foam. Mechanical air foam is produced by discharging under pressure a mixture of water and a foam stabilizing agent in such a manner that air, or some other gas, will be mixed therewith and the air will be entrapped in the stable bubbles of the resultant foam. Chemical foam is produced by the reaction of two chemicals, stored either in dry or solution form, Water and a stabilizing agent. The reaction produces a mass of carbon dioxide bubbles which are toughened, or rendered long-lasting by the stabilizing agent. Y

Heretofore, mechanical air foam has been discharged as a solid stream of air foam bubbles ready for application onto fire because the water, the stabilizing agent and the air, or other gas, are mixed and the foam produced upstream of the zone of discharge, or the discharge orice. The water fog foam referred to above is of the mechanical air foam type but is produced in an unconventional manner. A mixture of water and a stabilizing agent is brought to a zone of discharge and released under pressure to the atmosphere as two, or more, impinging streams. The impingement breaks up the mixture into a fog and air is entrained or entrapped in each water particle to produce the water fog foam.

Tank l1 of the apparatus disclosed in Fig. l has been described as containing water which is expelled by means of carbon dioxide vapor which is delivered thereto by the pipe line 20. If the carbon dioxide vapor is delivered to this tank I'l at the time the water is to be discharged through the pipe I6, the carbon dioxide vapor merely functions as the expelling or propelling medium for the Water. If the carbon dioxide vapor is delivered to the water tank I1 a considerable time in advance of the discharge of the water from this tank so that the water will be maintained under carbon dioxide vapor pressure for,.a substantial length of time, the water will be carbonated. If the apparatus of Fig. l is mounted on a vehicle that is moved some distanice from a fire station to the scene of a fire and the carbon dioxide vapor is delivered to the water tank Il prior to making the run to the fire, the agitation produced by the travel of the vehicle will assist in bringing about carbonation of the water in tank I1.

It has been determined that by employing carbonated water, either with a suitable stabilizing agent mixed therewith in the tank l1 or with a stabilizing agent added thereto so as to become mixed therewith while flowing through the pipe line I3, a new type of foam is produced. This new foam can best be described as a chem ical-mechanical air foam because the bubbles of the foam have entrapped therein both carbon dioxide vapor and air. That is to say, the carbon dioxide vapor comes out of solution when the carbonated water and foam stabilizer mixture is formed and this released carbon dioxide vapor with the air that is entrained at the time of imseam . r13 pingement -Aae -entrapped in the "water particles of theV fog. y 4

'Figure 6 discloses a water tank structure IIa which may be4 substituted for the'watertank Il of the apparatus disclosed in Fig. l when it is desired to use carbonated water u-nderall conditions'of operation of this apparatus. This tank I'la is supplied with carbon dioxide vapor fromthe carbon dioxide storage tank ll'fthrbugh thef'pipeline 2D and lthe control valveZo. In this arrangement, however, the `pipe line `2f9 extends inwardly ofthe tank Ila to'a point adjacentA its bottom so that the'lcarbn dioxide vapor'w'ill be required to bubble up through the waterstored in` this tank. Thebubbling of the f'arbon dioxide vapor through `the water will assist' i'n effecting carbonation of the latter. Additional *means to effect complete v`carbonation Yof the water byagitating the same is provided' and takesy the form of the stirring or agitating blades G5 'which aremounted on the s-l'iatt that extends through one end wallof the tank I'Iar for .being driven by the electric motor, or other prime mover. s1.. A n y y i It will be appreciated that this tank I'Ia can be employed in the apparatus of Fig. l, in place bf-the-ill'ustratedtank I'I, either when the apparatus of Fig. 1 is employed withY the foam stabiliingchemical supply tank I9 operating'as a result of` having valves .22" and l2,3 open or' when the foam stabilizer is premixed with the water inthe tank Ila and the chemical supply tank I9 `is rendered inoperative by closing valves 22 and 23.

Fig. "I' illustrates apparatus that is designed for generating chemical foam that is to be discharged with or independently of the carbon dioxide discharge. This apparatus includes the insulated storage tank `I5 for liquid-carbon dioxide which, preferably, isl maintained at a desired `subatmos'pheric temperature,'and its corresponding low vapor pressure, by thefcooling coil l thatfis included as apart of a'y mechanical refrigerating cycle.

-`Ijiquid carbon dioxide is withdrawn from the acter of the carbon dioxide pipe line 8, is suitably attached at itsouter end to the fog discharge ring I2a` and extends along a suitable portion of the pipe line 8 to be attached thereto by clamps, bands, or the like, I4a. If the pipe lines Ill and `If3a are exible for manual manipulation-suit elble'con'trol valves, not shown, yshouldy be inter- Control valvesiII and 'I2 varegprovi'ded' inthe braincljlesl of ktliiemanifold pipe 88 "for controlling and propO/r'toning'the delivery of fthebhmcal Chemical tank 69 provides a suitablesource of supply or bicarbonate of soda and a foamv stabilizingffagent dissolved in water. Tank "I'provides asuitablesource off-supply of aluminum sulphate dissolveldi'n water. Thereaction ofthese two chemicals is wellknown in the art. The proper mixture-'of' these two chemicals, withthe stabilizingagent; will be vconducted to the foam discharge ring I2'a by the pipe line I3a. The manner -i-n which this foam discharge ring I2a functions to deliver a'plu'rality of -solid streams of the carbon dioxide bubble type ofv` foam will be explained at a later point.

The two chemicalsolutions stored` in thetanks 59 andl are expelled by carbon dioxide vapor whichfis delivered by the pipeline 29 from the carb'cnfdioxi'de storage tank 6. 'This pipe line -20 is providedwith the same ilow controlling-Tand pressureg regulating valve2la referred to in connectionwith'the disclosure of Fig. 1. The delivery end of this pipe line 20 is formed into two branch lines "I3 an'dl4 which are illustratedas extending into the tanks 69 and'l to points located near"the"bott`oms thereof. When these branch lines T3=fand T4 are 'arranged in the manner illustrated, the'carbon idioxidevapor discharged into the tanks 69 and 'IIJ will be caused tofbubble up through the chemical solution stored in'these tanks. Theagitation of the solutions resulting from this upward movementy of the carbon'dioxide Vapor will help to carbonate the water of the two solutions. To further aid in carbonating this water, stirring blades 'I5 and'l are lo cated'in the tanks-69y and'lll respectively and are mounted on Shafts 'I1 .and 'I8 which 4extend throughthe tops'of 'the tanks tof be driven by e'lectric'motors, or vother prime movers, 'I9 and 80 respectively. l

Thisuse of carbonated water in preparing'the chemical solutions stored in the ltanks 69 and 1t `has been found to produce a chemical foam which is` richer in'carb'on dioxide gas; i. e'.,`-vlib erates more' of vsuch gas, than chemical foam that is produced from solutions'prepa'red with uncarbonated water.

Fig. '8 'discloses nre extinguishing apparatus which'- diners' from the disclosure of Figjl `only by the means' for producngthe chemical foam. The apparatus of Fig. 8 operates with aI stored supply of dry foam producing chemical, or chemicals, as distinguished from a supply oftwo' foam producingsolutions. For that reason, the salme reference characters will be -applied kto the correspendingl structural elements of Fig. Sand these 'elements will not lbe specifically referred lto.

' yInthis apparatus'ofFig. 8, the foam delivery pipe line" I3a,*has connected thereto a suitable storage hopprl-BI which functions to deliver at theV desired 'rate thedry powder chemical or ehemicals for producing the. foam. The hopper type of foam generating apparatus lis well known `rin the art and for that reason no attempt has been made to villustrate in detail the aspi'rating mechanism, etc., by-'ineans of'which the drypowder isldeliv'ered to Aand is mixedv with the flowing stream of water. Conventional hoppertypefoa'm generators are' of two-different styles. One'style uses a single foam producing powdered dry chem- 'ica'lwliich contains" all'of the necessary ingredients to initiate the chemical reaction for producing thel desired foam. The other style'uses two separate powdere'ddry chemicals which produce V'solutions at the generator, these `solutions acoja-14s subsequently being brought together, usually at the discharge outlet, so as to mix at that point to produce foam.

The illustration provided by Fig. 8 is of the single powder hopper type. It is to be understood, however, that a two-powder type of hopper may be substituted without changing the principle or function of the apparatus as awhole.

The dry powder chemical or chemicals used in this type of foam generating system are well known in the art and need not be specifically identified.

Suitable controls 82 are merely diagrammatically illustrated and function in a conventional manner to determine the rate of feed of the foam producing powder or powders to the water stream flowing through the pipe line |3a.

The water required to produce the foaming solution, when mixed with the powder, or powders, supplied by hopper 8|, is stored in the water tank 83. The water in this tank is expelled by carbon dioxide vapor pressure and the vapor pipe line 2U, with its control valve 20a., is illustrated for this purpose. Fig. 8, however, illustrates the pipe line 20 as extending to a point adjacent the bottom of tank 83 so that the liberated vapor will bubble up through the water to assist in carbonating the same. Agitation of this water to increase the degree and rate of carbonation is obtained by the stirring blades 84 mounted on the drive shaft 85 which extends outwardly of the tank 83 to be driven by the electric motor, or other prime mover, 86.

The combined carbon dioxide and foam discharge nozzle or apparatus disclosed in Figs. 9 and 10 is primarily intended for use in connection with the apparatus illustrated in Figs. 7 and 8. This discharge apparatus of Figs. 9 and 10, however, can be incorporated in or used with the apparatus of Fig. 1 when the water for the foam is carbonated in accordance with the disclosure of Fig. 6.

The carbon dioxide discharge portion of the nozzle assembly shown in Figs. 9 and 1,0 is the same as the carbon dioxide nozzle portion 9 vdisi, closed and described in detail in connection with Figs. 2 and 3. For that reason, the same reference characters will be applied to identical structural elements and no further description of this carbon dioxide discharge nozzle portion will be given at this time.

The foam discharging ring 12a is supplied with the desired foam producing solution by the pipe line |3a. This ring |211 is of hollow construction and merely includes a desired number of openings or orifices 81 through which solid streams of the chemical foam are discharged. These streams are arranged in parallelism with the axis of the carbon dioxide discharge nozzle portion 9 in the showing provided by Figs. 9 and 10. It will be understood, however, that the foam streams may be discharged at any desired angle with respect to the axis of the carbon dioxide discharge.

The discharge apparatus of Figs. 11 and 12 can be used to effect independent discharges, or a combined discharge, of carbon dioxide and mechanical air foam when substituted for the discharge apparatus of the system illustratedin Fig. 1.

Because the carbon dioxide discharge nozzle portion of the apparatus shown in Figs. l1 and 12 is the same as the nozzle portion 9 of Figs. 2 and 3, the same reference characters will be applied to like structural elements and the specic'description of these elements will not be repeated.

The water and foam stabilizer mixture provided by the system of Fig. 1 will be delivered to the discharge ring 88 by means of the pipe line I3. This mixture is discharged under the desired pressure through the series of openings or apertures 89. These discharged streams ow through the air gap 90 and are delivered to the foam discharge tubes 9|. While passing through the air gaps 90, air is entrained and mixes with the water and foam stabilizer in the tubes 9| so that solid streams of mechanical air foam will be discharged from the outer ends of the tubes 9|. This broad idea of entraining air in a mixture of water and a stabilizing agent to produce mechanical air foam is well known in the art and for that reason a more detailed description will `not be provided.

The disclosure of Figs. 11 and 12 illustrates the mixture discharge openings or apertures 89 and the foam generating and delivering tubes 9| as being arranged with respect to the axis of the carbon dioxide discharge nozzle portion 9 so that the solid foam streams will be discharged in parallelism with the carbon dioxide discharge. It will be understood, however, that the apertures 89 and tubes 9| may be so arranged that the solid foam streams willbe discharged at any desired angles with respect to the carbon dioxide stream.

Let us now consider the methods of extinguishing the various classes of fires that can be performed by the apparatusembodying this invention.

Class "A fires-Etznguished by cooling and quenching One of the best methods of extinguishing this class of fires has been determined to consist of rst attacking the re with a combined discharge of carbon dioxide and water fog to knock down or extinguish the iiame and partially cool the burning material and associated masses of heat absorbing materials or objects, and then follow up with a discharge of the water fog all by itself.

By so directing the initial discharge of carbon .dioxide and water fog that the carbon dioxide portion of the composite stream will strike the heart or combustion'zone of the re, the encircling discharge of free water fog will start cooling down the associated heat absorbing masses because of its wetting action. If the re zone is so large that its combustion zone will take up the entire discharge of the carbon dioxide and water fog, the heat of the re will convert the free Water fog to steam and this conversion will help to cool the burning material. After the name has been destroyed and the discharge of carbon dioxidev has ben stopped, the water fog discharge willv cover a considerably larger area, although its range has been reduced substantially because it cannot rely on the high Velocity carbon dioxide discharge as a carrier. The water fog discharge will be employed to thoroughly wet down the surfaces of the burnt material and the associated heat absorbing masses with the result that all glowing embers will be extinguished.

Of course, the initial attack on the fire may be performed with only a carbon dioxide discharge and the water fog discharge not be employed until the final stages of the extinguishment, or until after the name has disappeared. This method, however, is not as desirable because the combined carbon dioxide and water fog discharge possesses a higher total heat ab 17 sorbing valuev thandoes the` carbon dioxide when discharged by itself. Consequently, more carbon dioxide must be employed in carrying out this second method and, of course, carbon dioxide is more expensive .than water.

Because allof the above referred to foams are composed largely of water which has a pronounced coolngand wetting effect that is very eifective in the. extinguishment .of glowing ernbers, any one of the described foam discharges may be substituted for the water fog discharges in effecting extinguishment of Class A. It will be obvious, however, that the foam producing chemicals will be wasted unless the hazard is of suchv a size or character that the building up of a foam blanket to .prevent reiiash or rekindling is deemed necessary.

Class B fires-Requiring cooling and smother'ing `It has been determined that the best method of extinguishing this. classof res is by initially attacking the same 'with a combined discharge of carbon dioxide andfoarn. This composite discharge is continued .until `the iiame has disappearedand the associated heat absorbing masses have been cooled to a. temperature. below that at whichthe combustibleyapors rising from the surface of the: flammablek liquid willreignite. On extendediires `which Aarezlarger than the area covered bythe discharge stream when the discharge apparatus isheldstationary, it is necessary to begin the attack on onesideand sweep the discharge slowlytover vthe'surface of the burning material so astolsweepthe lire from one side to the other. During this action the combined discharge stream of carbon dioxide and foam is manipulated soas `to form `and maintain a continuous curtainbetween .the re and the flammable material which is no longer burning. A composite discharge will quickly extinguish the flame in the area whichit covers and will also leave behind onthe surface of the ammable fluid a thin film of foam `containing particles of carbon dioxidesnow. Thissurface lm will prevent any sudden reflash which Iwould ordinarily occur if .the operator allows the discharge stream to Waver for an instantso that a complete curtain is not maintainedbetween the re and the material that is not burning. Therefore, with this type of composite dischargethe operator will: have nodificulty in :extinguishing relatively large res which might otherwisebe impossible to control. After the i'nal portion has been extinguished, the foam is discharged by itself for the purpose of increasing the thickness of thefoarn blanket. If any of the flammable fluid has spilled over and remains on the surface of the surrounding ground, or the like, the final foam discharge is employed for blanketing down this free fluid. The foam yblanket that is thus formed on the surface of Ithe flammable iiuid that still remains in its original confining tank, pool, or the like, and on the surface fof the iiammable fluid that is lying on the surrounding territory, prevents reignition by accidentally created sparks, or the like. This blanketing'ofall of the freeammable fluid is avery important method-step in handling airplane crash res because such 'lires are almost always accompanied by spilling of a substantialquantity of lhigh octane aviation gasoline. This free gasolineis very readily reignited because all that'is'required is `Vfora lspark to be struck or createdby a wrecking tool: or the heel of a person engaged in rescue or`salvage work.

i8 Class "C fires- Requiring cooling and frequently quenching Fires involving electrical equipment can oftentimes be completely extinguished by the use of carbon dioxide all by itself. However, if a substantial amount of combustible insulating material is involved, glowing or smoldering portions of this material can best be quickly extinguished by quenching. Therefore, this class of fires can best be handled by rst attacking the re with a discharge of carbon dioxideby itself and this discharge is continued until the flame has been destroyed and the associated masses of metal that constitute theframework, casing, or the like, of the electrical equipment is thoroughly cooled. The Yglowing embers of smoldering insulating material can then be quickly extinguished by a very short discharge of water fog. This method of extinguishment results in the saving of a substantial amount of carbon dioxide and the final wetting down step can be accomplished with such a small volume of water that it effects very little if any permanent damage to the equipment.

1t is to be understood that I do not desire to be limited to the exact sequence of method steps described above nor to the speciiic form of the apparatus that has been disclosed as the method steps and apparatus that have been shown and described are to be taken as preferred examples only, and that various changes in the method steps and in the shape, size, and arrangement of structural parts may be resorted to without departing from the spirit of the invention or the scopeof the subjoined claims.

Having thus described the invention, I claim:

1. A method of extinguishing a re, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating foam, projecting the foam in an associated relation with respect to the carbon dioxide stream, and attacking the re with a combined discharge of the carbon dioxide and foam to extinguish the flame and form a cooling and smothering foam blanket on the involved material.

2. A method of extinguishing a fire, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating foam by the impingement of streams of a mixture of water and a foam stabilizing material, so associating the generated foam with the carbon dioxide stream that the carbon dioxide and foam will be simultaneously applied,.and-attacking the iire with a combined discharge of the carbon dioxide and foam to extinguish the flamev and form a cooling and smothering foam blanket on the involved material.

3. A methodof extinguishing a fire, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquidto produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating foam, projecting the foam insuch a relation to the carbon dioxide stream that aportion of the foam will be entrained by the `carbon dioxide stream for delivery to the point of application while the remainder of the foam will be carried to the point of application as an encircling envelope by the i9 aspirating action of the carbon dioxide stream, and attacking the ire With a combined discharge of the carbon dioxide and foam to extinguish the flame and form a cooling and smothering foam blanket on the involved material.

4. A method of extinguishing a fire, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating foam at one or more points in close proximity to the periphery of the formed carbon dioxide stream, projecting the foam in such an associated relation with respect to the carbon dioxide stream that the carbon dioxide and foam will be simultaneously applied to the same general area of the re, and attacking the fire With a combined discharge of the carbon dioxide and foam to extinguish the flame and form a cooling and smothering foam blanket on the involved material.

5. A method of extinguishing a rire, comprising effecting sudden release of liquid carbon dioxide to lower its pressure sufficiently to form na mixture of snow and vapor, eiecting separation of the snow and vapor from each other, forming the separated snow and vapor into a composite discharge stream, separately generating foam, so projecting the foam that it will be carried to the point of application by the carbon dioxide stream, and attacking the nre with a combined discharge of the carbon dioxide and foam to extinguish the flame and form a cooling and smothering foam blanket on the involved material.

6. A method of extinguishing a fire, comprising eiecting sudden release of liquid carbon dioxide to lower its pressure suciently to form a mixture of snow and vapor, effecting separation of the snow and vapor from each other, forming the separated snow and vapor into a composite stream in which the vapor surrounds the snow, separately generating foam, so projecting the foam that it Will carry to the point of applica.- tion of the carbon dioxide in closely associated relation with the surrounding vapor `portion of the carbon dioxide stream, and attacking the iire With a combined discharge of the carbon dioxide and foam to extinguish the ame and form a cooling and smothering foam blanket on the involved material.

7. A method of extinguishing a lire, comprising the steps of first attacking the re with a combined discharge o'f carbon dioxide and foam to quickly extinguish the flame, partially cool down the combustible material and associated heat absorbing masses, and form a thin cooling and smothering foam blanket on said material V*and masses; and then continuing the discharge of the foam by itself to increase the depth of the foam blanket until it is suiiicient to prevent reflash.

8. A method of extinguishing a re, comprising the steps of rst attacking the fire with a combined discharge of carbon dioxide and mechanical air foam to quickly extinguish the flame, partially cool down the combustible material and associated heat absorbing masses, and form a thin cooling and smothering foam blanket on said material and masses; and then continuing the discharge of the foam by itself to increase the depth of the foam blanket until it is sufcient to prevent reflash.

9. A method of extinguishing a fire, comprisf' l all Gil ing the steps of first attacking the fire with a combined discharge of carbon dioxide and chemical foam to quickly extinguish the flame, partially cool down the combustible material and associated heat absorbing masses, and form a thin cooling and smothering foam blanket on said material and masses; and then continuing the discharge of the foam by itself to increase the depth of the foam blanket until it is suicient to prevent rehash.

10. A method of extinguishing a re, comprising the steps of rst attacking the fire with a discharge of carbon dioxide to quickly extinguish the name and partially cool down the combustible material and the associated heat absorbing masses, and While the combustible material and associated heat absorbing masses are still partially cooled applying to their surfaces a cooling and smothering blanket of foam to prevent reignition or reflash.

11. In the method for extinguishing a ire involving flammable liquid conned in a tank, or the like, and spilled over a surrounding area, the improvement which comprises first attacking the nre with a combined discharge of carbon dioxide and foam to quickly extinguish the flame, to lower the temperature of the liquid and the associated'tank and other adjacent heat absorbing masses to a value below the reignition temperature of the liquid vapors, and to leave a foam deposit on the surfaces of the confined and spilled liquid; and then delivering to the surfaces of the conned and spilled liquid additional foam to build up a foam deposit on said surfaces that will prevent reflash.

12. A method of extinguishing a fire, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating Water fog foam, so associating the generated Water fog foam with the carbon dioxide stream that the water fog foam will be carried to the point of 1 application by the carbon dioxide stream, and

attacking the fire With a combined discharge of the carbon dioxide and water fog foam to extinguish the flame and form a cooling and smothering foam blanket on the involved material.

13. A method of extinguishing a fire, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid toproduce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating Water fog foam, projecting the water fog foam in such a relation to the carbon dioxide stream that a portion of the water fog foam will be entrained by the carbon dioxide stream for delivery to the point of application While the remainder of the water fog foam will be carried to the point of application as an encircling envelope by the aspirating action of the carbon dioxide stream, and attacking the re with a combined discharge of the carbon dioxide and Water fog foam to extinguish the flame and form a cooling and smothering foam blanket on the involved material.

14. A method of extinguishing a fire, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating

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