US2500428A - Fire extinguishing method and apparatus - Google Patents

Description

March 14, 1950 D. MYERS 2,500,428

FIRE EXTINGUISHING METHOD AND APPARATUS Filed Feb. .28, 1945 4 Sheets-Sheet l March 14, 1950 L. D. MYERS 2,500,428

' FIRE sx'rmcuxsnme METHOD AND APPARATUS Filed Feb. 28, 1945 v 4 sneets siheet 2 March 14, 1950 L. D. MYERS 2,500,428

FIRE EXTINGUISHING METHOD AND APPARATUS Filed Feb. 28, 1945 4 Sheets-Sheet 3 March 14, 1950 D. MYERS FIRE EXTINGUISHING METHOD AND APPARATUS 4 Sheets-Sheet 4 Filed Feb. 28, 1945 Patented Mar. 14, 1950 FIRE EXTINGUISHING METHOD AND APPARATUS Leonard D. Myers, Washington, D. C., as si gno to Cardox Corporation, Chicago, 111., a corporation of Illinois Application February 28, 1945, Serial No. 580,181

8 Claims, (Cl. 169-11) This invention relates to new and useful improvements in methods of and apparatus for discharging fire extinguishing mediums and for extinguishing fires.

The copending application, Serial No. 551,869, filed by Charles A. Getz, on August 30, 1944, amongother things, discloses and broadly claims a methodof and apparatus for discharging carbon dioxide and foam, either individually or in combination, to effect the extinguishment ofcertain classes of fires. For example, class B fires can be extinguished more quickly and effectively with an initial, brief application of carbon dioxide and foam and a final, prolonged application of foam by itself than with either carbon dioxide or foam when used alone, or with any other known extinguishing mediums when used alone or in any desired combination.

The aforesaid application specifically discloses mechanicalair foam as one of the foams that is used with carbondioxide to eifect the EX? tinguishment of fires. Mechanical air foam is produced by flowing under pressure a mixture of water and a foam stabilizing agent in such a manner that air from the, surrounding atmosphere will be drawn into the flowing mixture and entrapped in the stable bubbles of the resultant foam;

' As all foams are broken down by flame or intense heat, it will be appreciated that when mechanical. air foam is applied directl to flame or to intensely heated surfaces in a fire zone, before the water portion of the foam has had an opportunity *to cool down these surfaces, the mechanicalair foam .hubbles will be broken down andthe airentrapped therein willbe liberated, with the result that combustionsupporting oxygen is delivere'd to the fire. This is one of the principal differences. between mechanical air foam andchemical foam; i. e., thebubbles of chemical foaniare filled. with carbon dioxide vapor which is liberated when the bubbles are broken down and has a smothering efiect: which aidsin extinguishing afire.

Attempts have been made in the. pasttoprm duce mechanical foam which will not release oxygen to the fire by substituting an inert gas for the air that isdrawnintothe fiowin mixture of water tabil zin ag nt. These-prior a tempts ,have not proved satisfactory, or commer- .cially,practical,for the following reasons:

l very tq-t e ,fiowins mixture. g I e 2. Foam-bubbles formed with compressed inert gas .entrapped therein were found to be less stable or durable thanfoam bubbles containing air at atmospheric pressure because the internal pressure exerted by the compressed inert gas caused thebubbles to break down more readily.

3. Although it is entirely satisfactory to use air, instead of inert gas, after a fire isv subdued to the point where there no longer remains sufficient flame or intense heat to break down to a substantial extent the foam bubble formation, thereby effecting a reduction in the amount of inert gas required, this saving could not be realized in connection with these pr-iorattempts without the addition of a suitable switching valve in thesupply pipe for the inert gas.

Because of the above noted objections, the manufacturers of mechanical foam producing equipment of today provide for the use of air as the bubble entrapped medium, and depend ona prolonged, high rate ,of discharge for eventually effecting the desired extinguishment.

It is the primaryobject of this invention to provide a method of and apparatus for producing a fire extinguishing discharge whichccnsists of carbon dioxide and mechanical foam with the bubbles of the foam having entrapped therein carbon dioxide that is obtained from the carbon dioxide portion of the discharge.

A further primary object of the invention is to provide a method of and an apparatus forproducing a fire extinguishing discharge which consists ofcarbon dioxide that has its snow and vapor components separated and mechanical air foam with the foam bubblesha'ving entrapped therein carbon dioxide vapor that is obtained from the separated vapor component of the carbon dioxide discharge.

A still furtherimportant. object of the invention is the provision of a method of and apparatus for extinguishing a fire by applying thereto a combined discharge of carbon dioxide and mechanical foam, with the bubbles of the foam having entrapped therein carbon dioxide obtained from the-carbon dioxide portion of the discharge, untilthe flame and temperature conditions in the fire zone are such that the foam bubbles will not be materially affected thereby, and then applying to the fire a discharge of mechanical air foam alone, with the bubblesof the foam having entrapped .therein-air obtained from the surrounding atmosphere.

Another objectof the invention is to provide a fire extinguishing method and I apparatus for; producing a discharge of carbondioxide and mechanical foam, with the snow and vapor components of the carbon dioxide separated and arranged so that the vapor component shields the snow component from the surrounding atmosphere and with the mechanical foam being formed from water, a stabilizing agent, and vapor obtained from the shielding vapor component of the carbon dioxide portion of the discharge.

Still another object of the invention is to provide fire extinguishing apparatus which is operable to effect discharge of carbon dioxide alone, mechanical air foam alone, or a combination of carbon dioxide and mechanical foam which has carbon dioxide vapor entrapped in the foam bubbles.

A further object of the invention is to provide apparatus for producing a fire extinguishing discharge that consists of a dense carbon dioxide snow core, a carbon dioxide vapor envelope surrounding and shielding the snow core, and one or more streams of mechanical foam, having carbon dioxide vapor obtained from the aforesaid vapor envelope entrapped in its bubbles, arranged adjacent the margin of the carbon dioxide vapor envelope.

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 specification and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a front elevational View of one form of fire extinguishing apparatus embodying this invention,

Figure 2 is a central vertical sectional view taken on line 22 of Fig. 1,

Figure 3 is a front elevational view of a modifled form of fire extinguishing apparatus embodying this invention,

Figure 4 is a top plan view of the apparatus shown in Fig. 3,

Figure 5 is a vertical sectional view taken on line 5-5 of Fig. 3, and

Figure 6 is a horizontal sectional view taken on line 6-6 of Fig. 5.

In the drawings, wherein for the purpose of iilustration are shown the preferred embodiments of this invention, and first particularly referring to Figs. 1 and 2, the reference character A designates in its entirety the carbon dioxide discharge portion while the reference character 13 designates each one of the two foam generating and discharging portions of the complete fire extinguishing apparatus embodying this invention.

The carbon dioxide discharge portion A of this apparatus will be described first.

The carbon dioxide discharge portion or nozzle A is supplied with liquid carbon dioxide by means of the pipe line lil which may extend to any suitable source of supply, such as a bank of high pressure cylinders or an insulated and automatically refrigerated storage tank. It is preferred, however, to obtain the liquid carbon dioxide from the insulated and refrigerated tank so that the liquid carbon dioxide can be delivered to the discharge nozzle A at a predetermined, constant subatinospheric temperature, and its corresponding low vapor pressure because of the higher percentage of snow yield that would be obtained.

Any suitable control valve, not shown, should be provided in the pipe line ill for starting and stopping the flow of liquid carbon dioxide through the latter. The pipe line ID may be of a rigid character if the apparatus of Figs. 1 and 2 is employed as a part of a fixed fire extinguishing system, or if the apparatus is associated with mobile fire fighting units of the type disclosed in the Eric Geertz patent, No. 2,352,379, issued June 2'7, 1944. This pipe line Ill, also, may take the form of a flexible hose line if desired. If a flexible hose line is employed, several feet of the pipe line ill located immediately adjacent the discharge nozzle A will take the form of a more rigid handle or playpipe to facilitate manual handling of the apparatus.

The carbon dioxide discharge nozzle A is of the type disclosed and broadly claimed in the patent to I-Iilding V. Williamson, No. 2,357,039, issued August 29, 1944. The liquid carbon dioxide supply pipe line 80 is suitably threadedly connected to the stem or shank H of the nozzle A. This stem or shank II is provided with a bore I2 for delivering the liquid carbon dioxide to the interior of the body portion of the nozzle. The outer or forward end it of this bore communicates with the interior of a deflector element and cooperates with this element to form a flow path 5 or the liquid carbon dioxide. The stem or shank i i has formed on its outer end a radially extending flange l4 formed with a circular series of orifices 15 through which the liquid carbon dioxide is released to permit sudden expansion so that its pressure will drop below pounds per square inch, absolute, which will cause a certain percentage of the liquid to flash to snow while the remainder of the liquid is vaporized. This annular flange i4 is provided with a circular series of threaded openings [6, for a purpose to e explained at a later point. Exteriorly, the stem or shank l l is provided with a rearwardly curved or flared surface ll that terminates in a shoulder it.

The deflector element referred to above is identified by the reference character [9 in Figs. 1 and 2. This deflector element is secured to the flange M by means of the series of screws 20 that are threaded into the holes I6 of the flange M. The deflector is partially hollowed out so as to control the direction of flow of the liquid carbon dioxide to the discharge orifices l5. For that reason, the interior of the deflector is provided with a conically shaped projection 2! that is axially aligned with the bore [2 of the shank or stem II. The interior of the deflector element 19, radially outwardly of the spreading projection 2|, is provided with the curved surfaces 22 that function to change the direction of flow of the liquid carbon dioxide so that it will be directed rearwardly through the discharge orifices IS. The inner or rear portion of the deflector element [9 is boiled or curved outwardly at 23 to form an internal curved surface 24 that lies opposite to and cooperates with the curved exterior surface I! of the stem or shank ll. Fig. 2 clearly shows that these two cooperating surfaces l1 and 24 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 flashing of whatever liquid may remain as a part of the flowing material. The outer portion of the deflector element [9 is illustrated in Figs. 1 and 2 as being formed with radial ribs 25 which form the valleys 26 that are partially longitudinally curved so as to deflect forwardly or axially agtoogaaa 5v any-*of the discharged medium that "comes in contact with the same;

"The-defi'ectorelement l9, and the cooperating portion I! of the stem or shank ll, areenclosed within a chambered body or casing which is formed by-the inner portion 21 and the outer portion 28. The inner portion 210i the body or casing is dish-shaped and is centrally cut away-"at 29 to permit the inner portionof the stem or' shank II to passtherethroughso that the"shoulder"*l8 will act as a seator an abutment 'for"this inner portion 2'! of'thebody or casing; Any suitable means may be provided for "securing :the body or casing portion 21 to the shoulder" portion 18, such-asby-weldingor-by the use of suitable screws or both: The outer portion 28 "of "the 'bodycr casing-is of cylindrical shape'and-has'its inner edge portion overlapping or itelescopically"associated with the outer marginal'edge portion of"the inner-body'part 21 to provide-a lapped joint '30. Rivets, welding, or the like; may be employed" for rendering this joint'permanent. Figs. land 2 clearly show that the body'or casing; of'the carbon dioxide disch'argenozzle 'cooperateswith the stem or shank H to provide a closed rear wall while leaving the front ofthe: apparatus entirelyopen. The body or casingadditionally cooperates with the stem or shank II and the deflector element I9 to form an annular chamber for receiving the circular series of flow controlling and directing unitsi3'l;

These units 3| are equally spaced around and extendradially of the stem or shank I! and the deflector element l9. Each one .of these units include a semi-circular-or semi-cylindrical band 32 which is flanged at both of its longitudinal edges 33; see Fig. 2. The inner transverse edge 34 of each one of these bands 32 is suitably anchored in close prox'im'ityto or "in contact with theperiphery of the flaredporti'on' or surface I! of the stem or'shank" l l. The outer edge 35 of each one of these. bands 32 terminatesin the plane "of the outer face of the body or casing portion 28-and the outer edges-of the deflector element" ribs 25.

The opposite sides of each-one of these-flow controlling and directing units 3l areformedby wall members 36 which lie inside of the edge flanges 3-3 and are suitably; secured thereto. Figs; 1' and 2 show the opposite side walls of "eachadjacent'pair of units'3l as being formed by'a'single piece ofsheet material with the center or intermediate portion of each one of these side 'wallforming pieces designated by thereference character .31. These center or intermediate portions 31 function to bridge-the gaps or spaces between the inner edges or sides of adjacentiunits' 3|.

.Fig; 2 "clearly disclosesrtheaside walls 36 of'the several units 3|: as having apertures 33 formed (therein. These apertures are located in the 'outer'orfront halves of the side walls 36; i. e., relatively closeto'the'outer edges 35 of the bands .32., Each flow controlling and deflecting unit 3.!v has mounted within the same a plow-shaped deflecting and separating element '39. These elements' are' of V- or wedge-shape'in section with :mountingiflanges 43 formed on'the sides thereof for securing; such as bywelding, the .elements 3.3 intheir proper placeswithin theunits 3 I. Fig.2 'discloses' these deflecting and separating elements 39 as beingarranged with respect tothe side wall openingsor aperturesr38 so that :the

llateralnslopingpssurfaces: 4 Loiiieachrcelement 39 will split or spread any material iflowing through the interior of a unit 31 so that this material will be deflected through the cooperating side wall openings or apertures 38. These elements the inner surfaces of the outer end portions of their associated bands 32. In other Words, a space or gap is left between the inner surface of the band 32 of eachone of the units 3i and the outer edge 42 of its associated deflecting and separating element 39 through which the extinguishing medium may flow to the outer edge 35 of the band 32.

The mode of operation of thiscarbon dioxide discharge nozzle is explained in detail in the aforesaid I-Iilding'V. Williamson patent and for that reason its mode of operation will be only generally set forth herein. Liquid carbon dioxide, of any desired pressure and temperature, will be delivered to the bore of the shank or stem l I and'will flowas a liquid to the discharge oriflees 55. As the liquidcarbon dioxide leaves these orifices, 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 flowing surfaces H and 2d, therefore, takes the form of a mixture of snow and vapor. Depending upon the temperature of the liquid carbon dioxide that is delivered to this discharge nozzle, a certain percentage of the same-will flash into snow as a result of the sew-cooling action that is produced. In other words, the entire discharge from the peripheral mouth, formed by the outer edges of the surfaces H and 2 will consist of a mixture of snow and vapor.

This snow and vapor mixture, as it leaves the aforesaid-peripheral mouth, will be flowing in a truly radial direction. Some portions of the mixture will pass directly into the various flow controlling and directing units 3!. The remainder of the mixture will be split and deflected laterally in opposite directions by the axially extending portions 3'! of the side wall forming pieces 36. These deflected portions of the mixture. therefore, will be directed into theseveralunits 3i. The curved bands 32 of the flow controlling and directing units 3! will deflect the flowing mixture from its straight line, radial path'and convert this straight line flow into a curvilinear flow or motion. As the carbon dioxide snow of the mixture is many times "more dense than the carbon dioxide vapor, and as the velocity of both of these components is the same, the snow'ofiers' more resistance to the deflecting force exerted by the obstructing, curved bands 32 with the result that the snow will. move to the outer side of. each one of these curvilinear flow'paths for the material. The snow, 'in seeking this outer portion of each flow path, will'crowd or force the vapor inwardly away from the inner surfaces of the various bands 32. The difference in density of the snow, as compared'to the vapor, therefore, effects asegregation of these two components.

The snow is segregated at or close to the outer side or each one of the curvilinear flow paths while the vaporis segregated on the inner'side of each path.

As the segregated snow and vapor reach the outer side of each one'of'the flow controlling and The inwardly positioned, segregated vapor, however, strikes the sloping surfaces 41 of the various elements 39 and is directed laterally through the side wall apertures 38 into the portions of the body or casing which lie between adjacent units 3!. The segregated and separated snow passes radially outwardly beyond the edges 35 of the several bands 32 and is directed into the valleys 26 of the deflector element [9. The curved inner surfaces of these valleys deflect the snow so that it will flow, or will be discharged, to the atmosphere in an axial direction with respect to the entire carbon dioxide discharge nozzle. This discharge of all of the separated snow from all of the units 3! causes the snow to be assembled into a compact, dense core. The separated vapor will leave the spaces between the adjacent units 3! and will flow in an axial direction relative to the discharge nozzle. The vapor is in this way discharged radially outwardly of the dense snow core. Because the areas of discharge for the vapor are spaced from each other by distances that equal the width of the fiow controlling and directing units 3i, the vapor discharges will be separated from each other immediately adjacent the front face of the carbon dioxide discharge nozzle. However, the various vapor discharges will blend together a short distance in advance of the nozzle and will form a surrounding or enclosing vapor envelope for the compact, dense snow which forms the core of the composite discharge of carbon dioxide.

From this description of the mode of operation of the discharge nozzle for the carbon dioxide, it will be appreciated that there is provided a discharge stream which is of substantially circular or cylindrical shape in transverse section. In Fig. 2 of the drawings, the dotted lines D are intended to represent the peripheral margin of the compact, dense snow core. All of the carbon dioxide that is discharged radially outwardly of these lines D, therefore, will be the separated carbOn dioxide vapor that forms the snow shielding envelope.

The foam generating and discharging portions B of the fire extinguishing apparatus disclosed in Figs. 1 and 2 now will be described in detail.

It will be noted from the two figures of the drawings that the two foam generating or discharge portions, or guns, B are located on diametrically opposite sides of the carbon dioxide discharge nozzle A and that these foam guns are structurally or operatively associated with a substantial portion of the periphery of the carbon dioxide nozzle. It will be appreciated that the size of the various elements that constitute each one of these foam guns will determine to a considerable extent the volume or quantity of foam that is generated and discharged. Therefore, if a greater total volume of foam is desired for certain extinguishment work, three or more foam guns B can be provided and distributed or spaced equal distances from each other around the periphery of the carbon dioxide discharge nozzle A. Additionally, if a lesser amount of foam is desired, one of the two foam guns B, illustrated in Figs. 1 and 2, can be dispensed with.

Each one of these foam guns is illustrated as having a pipe line 45 which is employed for supplying a suitable mixture of water and any desired, commercial foam stabilizing agent. This mixture, also, can include a suitable anti-freeze material or chemical when the fire extinguishing apparatus is used under ambient temperature conditions that would cause the water to freeze.

The water and stabilizing agent mixture can be supplied from any suitable source and is intended to flow through the pipe lines 45 under any desired pressure. It will be noted that these pipe lines are intended to extend longitudinally of and to be grouped with or attached to the carbon dioxide supply pipe line I0. Additionally, these foam mixture pipe lines 45 curve around or radially and axially of the periphery of the carbon dioxide discharge nozzle A. These pipe lines 45, therefore, will be flexible or rigid depending upon the character of the pipe line It and the use to which the fire extinguishing apparatus is applied; i. e., incorporated in a fixed fire extinguishing system or used as a discharge device for a hose line.

Each one of the pipe lines 45 extends to and is suitably connected with a coupling or discharge manifold 46. This coupling or manifold is hollowed out and is provided with a suitable number of orifice tips 41 mounted in its front wall 48 and adapted to discharge the water and stabilizing agent mixture or solution from the coupling or manifold. A suitable strainer element 49 is mounted in the element 46 and functions to separate out foreign matter and solid particles that might clog the tips 41.

Suitably attached to the discharge end of the coupling or discharge manifold 46 is a hollow member 50 that functions to provide a foam generating chamber 5| and a pick-up spout 52. This pick-up spout portion 52 of the member 50 is illustrated in Figs. 1 and 2 as extending to the annular space formed within the outer portion 28 of the body or casing and the peripheries of the associated flow controlling and directing units 3|. That is to say, the outer halves of these units 3| curve radially inwardly away from the body or casing portion 28 to provide space for the inlet throat 53 of the pick-up spout 52.

Fig. 1 shows this inlet throat 53 of each pickup spout 52 as being aligned with three of the carbon dioxide vapor discharge spaces that are left between the flow controlling and directing units 3!. Therefore, when carbon dioxide vapor is being discharged by the carbon dioxide nozzle A, some of this vapor will enter each one of the two pick-up spouts 52 and this vapor will be delivered to the foam generating chambers 5|.

The bringing together of the carbon dioxide vapor and the mixture or solution of water and foam stabilizing agent in the chambers 5i causes foam to be produced. This foam has the carbon dioxide Vapor entrapped in its bubbles. The foam generated in each chamber 5| is discharged through the associated foam delivering and directing tube 54.

These delivering and directing tubes 54 are illustrated in Figs. 1 and 2 as having their axes arranged in parallelism with the axis of the carbon dioxide discharge nozzle A. It will be appreciated, however, that these foam tubes 54 may be positioned so that their axes will form either acute or obtuse angles with respect to the axis of the carbon dioxide discharge nozzle A. If the axes of the foam directing tubes 54 are arranged at acute angles with respect/to the axis of the carbon dioxide discharge nozzle A, the resultant foam streams will be directed into the carbon dioxide stream for being blended with or entrained by the carbon dioxide. If the axes of the foam directing tubes 54 form obtuse angles with respect to the axis of the carbon dioxide discharge nozzle A, the foam streams will be caused to diverge or spread out relative to the a combined .dischargeof carbon dioxide and foam by openin all ofsaid. valves. If it is desired to: discharge only" carbon dioxide, the control valves-for thersupply pi-pe'lines 45 will be closed. If zrit .is desired towdischarge only. foam, the corn trol valves for. the: ipe lines 45 will-be opened and the control valve for the :carbon dioxide supply'line- ID will be closed; As'no carbon dioxide vapor will be dischargedlbyrthe nozzle A under this lastmentioned operating condition; the pick- 11p'Sp011tSf52 will not receive. any'carbon dioxide vapor. However, the aspirating; action produced by the discharge of I water and a .foam r stabilizing agent from the orifice tips. through the gen cratingchamber 5land: into thealigned'foam delivering" and directing tube, 54 willcause air from the surrounding atmosphere-to be drawn into. each pick-up. spout 52 through its inlet throat 53;. This atmospheric air Willi be delivered to, the foam generating chambers 5land will be entrappedinthe bubbles of the foam produced in these chambers.

Figs. Sto 6. inclusivev disclose amodified form of, fire fighting apparatus which. is dsignedfor producing acombined discharge. of carbon dioxideand foam or discharges-of carbon dioxide by itselfand dischargesof fOambyitself. The difference between the discharges producedb'y the apparatus of Figsv 3 to 6 inclusive and the apparatus .of' Figs. 1 and- 2 relates primarily to the cross sectional shape" of." the discharge streams; With the apparatusof Figs. 1 and21 thecarbon dioxide stream and the". foamstreams are each'of circular" cross section: With 5. the" apparatus of Figs. 3to"6"inclusive', the single carbon dioxide stream and each one of the several foam streams is of elongated shape'in cross section; or'with each stream having a I majorand a' minor cross sectional dimension. Thetype of discharge provided by the apparatus of Figs. 3*to 6 inclusive is best suited'for extinguishing ground fires or for applying the extinguishing medium over a large surface area ofa pool or 'confinedbodyof-fiam' .m'able fluid. Due 'to'the large surface coverage provided by the apparatus of Figs. 3 to 6 inc1usive; this apparatus'can be installed in a fixed positionwith' respect -to'thehazard or it"can be mounted onthe front" ofaflmobile fire fighting unit;

rangement'of-the'foam: guns H 1 with respect to T the. =carbon :dioxide nozzle-G: A's-illustrated; .two of.;the foam guns are associated withthe-upper longitudinal imarginof .1 the. carbon 'dioxidesnoze zle while two additionall foam guns 2: are? assor ciatedziwith thedowerrlon'gitudinal marginm" thecarbon diOXidB IIOZZIGw Each one of these longitudinally aligned pairs of foam guns extends throughouta-major portion of the lengthof the carbon dioxide (nozzle. It will be appreciated that the combined length of each aligned pair of foam guns "may be increased or decreased as desired to vary the volume of foam that is generated with reference to the volumeof carbon dioxide that is discharged by the nozzle G.- Additionally, either the upper or the lower pair of foam guns may be dispensed with if only one pair of foam guns is required, or will produce a sufficient quantity of .foam for a given type of hazard. Under certain operating conditions, it may be necessary-to employ only one ofthese foam guns H in combination with the carbon dioxide discharge nozzle G. When only one foam gun-is employed-it, preferably, will be centrally located with" respect to-the length of the carbon dioxide nozzle G and it may be associated with either the top or the bottom longitudinal margin of the carbon dioxide nozzle.

The-carbon dioxidenozzle portion of this fire extinguishing apparatus is best illustrated in Figsiii to 5 inclusive and the detail structural features will be describedin'connection with these figures.

This carbon dioxidetnozzle G is-of the same general construction as: that disclosed. in the Hilding. V. Williamson Patent No. 2,357,040, issued August 29, 1944. This nozzle includes a supplypipe line 55*which is employedfor deliver-- ing liquid carbon dioxide to' the nozzle. This pipeline may receive it's'liquid carbon dioxide from'either a bank or high pressure cylinders, or from a'single insulatedand automaticallyrefrigerated storage tank in the same manner as has been described in connection with the carbon dioxide nozzle A of Figs. 1 and 2'. The forward end of the pipe line 5511s connected to the right angularly arranged branches 56and 51. These branches extend in opposite directions and are suitably connected to the intermediate portions of" discharge pipes 58 and 59 respectively. The

pipes 58 and 59 are illustrated in Figs. 3 and 5 a's'being arranged in parallelism with respect to each other. These discharge pipesare suitably closed at their opposite outer ends and each pipe is" provided with a longitudinallyarranged series of discharge apertures or orifices 66. Fig. 5di scloses these orifices or apertures as facin in a generally rearward direction, rather than a forward direction, and'it is to be understood a that the apertures or orifices may be spacedat any. desired or suitable distance from each other.

Each one of these apertured discharge pipes 5-8 and 59. isfarranged within a merging and segregating chamber 6!. These chambers are arranged in parallelism with each other and each one. is provided with a curved rear Wall 62 that is joinedtothe side, parallel walls 53. Each oneof these chambers 61 is entirelyopen at itsfront, orat the portion opposite its-curved rear wall w, and: both endsof these chambers 75 to the *outer surfaces 'of the curved inner-walls 11 B2 of the chambers for further interconnecting these two chambers.

By inspecting Fig. 5, it will be seen that the longitudinal series of discharge orifices or apertures 60 of each discharge pipe 58 or 59 point or face in the general direction of the zone or region where its associated rear, curved chamber wall 62 merges with the outer side chamber wall 63. The importance of this direction of discharge will be apparent as the description, proceeds.

The mode of operation of this carbon dioxide discharge nozzle now will be described. Liquid carbon dioxide of any desired temperature, and corresponding vapor pressure, will flow under its own vapor pressure through the pipe line 55 and the branch lines 56 and 51 to the parallel discharge pipes 58 and 59 respectively. The liquid carbon dioxide in these discharge pipes will be released to the interiors of the chambers 5| through the constricted orifices or apertures 60. Due to the sudden drop in pressure which occurs as a result of releasing the liquid carbon dioxide in this manner, the liquid is converted to a mixture of snow particles and vapor. Each aperture or orifice 60 will provide a separate jet or stream of this carbon dioxide mixture. These jets or streams will partake of straight-line motion until their paths are obstructed by the inner surfaces of the chamber walls. The curved formation of each chamber rear wall 62 will cause the flowing mixtures of carbon dioxide snow and vapor to be deflected so that the said normal straight-line motion will be converted to a curvilinear motion. In addition to partaking of this curvilinear motion, the snow and vapor mixtures of the several streams or jets released into each one of the chambers 6| will be permitted to spread longitudinally of their chamber with the result that the several jets of mixture will merge to form a continuous mass equal in length to each chamber 6|.

The curved surfaces of the rear chamber walls 62 will function to change the direction of motion of the released carbon dioxide snow and vapor. Because the carbon snow of the mixture is many times more dense than the carbon dioxide vapor, and because the velocity of both of these components is the same, the snow offers more resistance to the deflecting force provided by the rear, curved chamber walls. The snow, therefore, will force its way to the outer side of the curvilinear path of flow of the material with the result that it will displace the vapor or force it to seek a path of flow away from the interior surface of the chamber walls. The difference in density of the snow, as compared to the vapor, therefore, brings about a segregation of these two components; i. e., the show will form a flowing layer in contact with the inner wall surface of each chamber while the vapor forms a superimposed layer that is spaced from the surface of the chamber wall.

The desired segregation of the snow and vapor is accomplished by the time the discharge reaches the open front of each one of the chambers BI. The snow layer for each chamber will be arranged adjacent the inner side wall 63 while the vapor layer will be arranged outwardly of the snow layer, or adjacent the discharge pipe 58 or 59. The final carbon dioxide discharge stream, therefore, will be formed by the segregated discharges from the two parallel chambers. The snow layers from the two chambers will lie adjacent to each other and immediately will merge. The vapor layers of the two discharges will be located out- 12 wardly of, or above and below, the merged snow layers and will sandwich the snow therebetween. It will be appreciated, therefore, that the final carbon dioxide discharge will consist of a core that is formed by the two merged snow layers with the vapor layers shielding the snow core from the surrounding atmosphere. This final discharge stream will have a width which corresponds with the length of each chamber while the depth or thickness of the final stream will be approximately equal to the distance between the adjacent sides of the discharge pipes 58 and 59.

Each one of the foam generating and dischar ing guns H of the apparatus shown in Figs. 3 to 6 inclusive will function in the same manner as the foam guns B of the apparatus shown in Figs. 1 and 2. Therefore, the description of the foam guns H will be presented as briefly as possible and will serve the purpose of only specifically describing the differences in structural design.

Each one of these foam generating and discharging guns is provided with a supply pipe line 5! that delivers a mixture of water and a foam stabilizing agent to the coupling or discharge manifold 68. This coupling or manifold of each gun is of elongated formation in longitudinal section. It is hollowed out, or chambered, so as to uniformly deliver the mixture of water and stabilizer to the longitudinally aligned series of orifice jets 59. These jets function to deliver the mixture into the foam generating chamber ll) of each gun. A suitable strainer H is provided at the entrance or inlet for each coupling or discharge manifold 68 to separate out solid particles of foreign matter that might clog up the jets 69.

The foam generating chambers 10 of the two guns H are formed in the members ll Which are so shaped as to provide pick-up spouts l2. These pick-up spouts are provided with inlet throats 13 that are arranged to receive carbon dioxide vapor from their respective segregating chambers 6|.

This picked-up carbon dioxide vapor is delivered to the foam generating chamber ll] of each member H and is so mixed with the water and foam stabilizing agent solution that the resultant foam has the carbon dioxide vapor entrapped in its bubbles. This generated foam is discharged to the delivering and directing tubes 14. By inspecting the several figures, it will be seen that these tubes 14 are of elongated shape in transverse section or are provided with major and minor cross sectional dimensions.

As was noted in connection with the fire eX- tinguishing apparatus of Figs. 1 and 2, the foam guns H of the apparatus shown in Figs. 3 to 6 inclusive will function to produce ordinary mechanical air foam when the carbon dioxide nozzle G is not operating. That is to say, the pickup spouts 12 will have air from the surrounding atmosphere drawn therein by the aspirating action produced by the discharges of water and a foam stabilizing agent delivered by the orifice tips 69.

1 It is to be understood that I do not desire to be limited to the exact order of method steps as they have been disclosed, for variations and modifications of the same, which fall within the scope of the accompanying claims, are contemplated. It further is to be understood that the particular types of apparatus herein shown and described are tobe taken as preferred examples of the invention, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. A method of discharging a fire extinguishing medium, comprising effecting sudden release of liquid carbon dioxide to lower its temperature sufficiently to form a discharge stream of snow and vapor, separately generating foam by mixing carbon dioxide diverted from the aforesaid discharge stream with a mixture of water and a foam stabilizing agent flowing under pressure, and projecting the generated foam as a stream 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 a'fire.

2. A method of discharging a fire extinguishing medium, comprising effecting sudden release of liquid carbon dioxide to lower its temperature sufiiciently to form a mixture of snow and vapor, separating the snow and vapor components from each otherand forming them into a composite discharge stream, separately generating foam by mixing carbon dioxide vapor diverted from the aforesaid composite discharge stream with a mixture of Water and a foam stabilizing agent flowing under pressure, and projecting the generated foam as a stream 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 a fire.

3. A method of discharging a fire extinguishing medium, comprising effecting sudden release of liquid carbon dioxide to lower its temperature sufficiently to form a mixture of snow and vapor, separating the snow and vapor components from each other and forming them into a composite discharge stream with the vapor shielding the snow from the surrounding atmosphere, separately generating foam by mixing carbon dioxide vapor diverted from the vapor shielding portion of the aforesaid composite stream with a mixture of water and a foam stabilizing agent flowing under pressure, and projecting the generated foam as a stream 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 a fire.

4. A method of discharging a fire extinguishing medium, comprising discharging carbon dioxide snow and vapor into the atmosphere in the form of a stream, completely generating foam at a location removed from the stream of carbon dioxide by mixing water, a foam stabilizing agent and carbon dioxide diverted from the aforesaid stream to said foam generating location, and projecting the generated foam as a stream paralleling and flowing in the same direction as the carbon dioxide stream.

5. Fire extinguishing apparatus, comprising means for producing and discharging a stream of carbon dioxide snow and vapor, a foam generating chamber, means for delivering to said chamber a mixture of Water and a foam stabilizing agent, means for delivering to said chamber carbon dioxide withdrawn from the carbon dioxide stream, and means for discharging and directing the generated foam from said chamber as a stream flowing in the same general direction as the carbon dioxide stream.

6. Fire extinguishing apparatus, comprising means for producing and discharging a stream of carbon dioxide snow and Vapor, a foam generating chamber closely adjacent the aforesaid means, means for delivering to said chamber a mixture of Water and a foam stabilizing agent, means for delivering carbon dioxide vapor to said chamber for entrapment in the bubbles of the foam, and means for discharging the generated foam from said chamber as a stream flowing in the same general direction as the carbon dioxide stream.

7. Fire extinguishing apparatus, comprising means for producing and discharging a stream of carbon dioxide snow and Vapor, means for diverting carbon dioxide vapor from said stream, and means for producing and discharging in close proximity to the carbon dioxide stream a foam stream having entrapped in its bubbles the carbon dioxide vapor diverted from the carbon dioxide stream.

8. A method of extinguishing a fire, comprising the steps of first applying to the fire area a combined discharge of carbon dioxide and a foam which is completely generated, at a location removed from the discharged carbon dioxide, by mixing a foam stabilizing agent and carbon dioxide diverted from the aforesaid discharge, and, after the fire has been subdued sufliciently to permit the foam bubbles to remain intact, then applying to the fire area a discharge of foam having air from the surrounding atmosphere entrapped in its bubbles.

. LEONARD D. MYERS.

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

UNITED STATES PATENTS Number Name Date 2,352,399 Myers June 27, 1944 2,387,935 Myers Oct. 30, 1945 2,387,963 Williamson Oct. 30, 1945 2,414,683 Williamson Jan. 21, 1947 FOREIGN PATENTS Number Country Date 658,328 Germany Mar. 10, 1938

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