US2940515A - Thermostatically controlled liquid fuel burner - Google Patents

Description

June 14, 1960 Filed R. H. HUNTER ETAL THERMOSTATICALLY CONTROLLED LIQUID Dec. 3l, 1954 FUEL BURNER 2 Sheets-Sheet 1 4 'da' 1% 'x I N VEN TORS ROBERT H HUNTEI?- ABE u. HANJE s By HABE/S VV-SM/TH ATTOENEYS June 14, 1960 R. H. HUNTER Erm.

THERMOSTTICALLY CONTROLLED LIQUID FUEL BURNER 2 Sheets-Sheet 2 Filed Dec. 31, 1954 5 WNMS M www A my r E 1 N w s .d w

\ \\\\\\\ll1 if Patented June 14, 1960 THERMOSTATICALLY CONTROLLED LIQUID FUEL BURNER Robert H. IIunter, Gates Mills, Abe-J. Hanja, Cleveland, and Harris W. Smith, Parma, Ohio. (all of 1550 E. 17th St., Cleveland, Ohio) Fued nec. 31, 1954, ser. No. 419,014 20 claims. (cl. 15s- 33) This invention relates to liquid fuel burning devices, more particularly to torches of the type that project the fuel into a combustion supporting atmosphere from a nozzle, although the principles embodied in the invention have application in other types of fuel burners.

In the operation of burners that utilize pressurized fuel supply systems, the fuelis, in one arrangement, conditioned for burning by vaporization in a heated generator or in passing through a heat retaining fuel ejection member. Representative of this type of fuel burner is the conventional blow torch used by plumbers and steam tters. One of the objections to vaporization of the fuel in a generator or by heating of the member from which it is projected is the necessity of using a special fuel that is completely vaporized by the heat in order to avoid leaving a residue in the passages of the member in .'hich itis heated. Thus, it is impossible to use the common internal combustion engine fuels in conventional heat vaporizing torches, since such fuels customarily contain gums, resins, and additives such as tetraethyl lead that are deposited in the fuel vaporizing passages. Such deposits eventually render the burner inoperative, as does deposited carbon.

In another arrangement for burning liquid fuels containing non-vaporizable gums, resins or additives, the fuel is mixed under pressure with a small quantity of air so that the fuel-air mixture can be projected into a combustion supporting atmosphere and will maintain combustion, the small quantity of pre-mixed air being adequate to initiate combustion of the projected mixture in continuous fashion. A representative fuel burning torch of this pre-mixed air type is shown in co-pending application for patent, Serial 'Number 457,803, led September 23, 1954, on Instant Flame Torch.

In the torch of the patent application referred to, the fuel is contained in a sealed metal tank or vessel. A charge of air under pressure is developed by a manually operated pump carried by the tank, the air being charged into the space above the fuel in the tank or vessel. Air thus held under pressure is led into a mixing chamber in a metal block that surmounts and is carried by the tank. Fuel is led into the same mixing chamber by -a conduit that extends downwardly through the air and fuel to the bottom of the tank. One of the objections to the fuel-air mixture torch is the depletion of the Vair charge in the top of the tank, necessitating intermittent manual pumping or other replenishment, in order to keep the torch in operation.

It is, therefore, one of the principal objectives of the present invention to overcome the diiculties heretofore experienced with both the fuel vaporizing torch in which the vaporization is effected by heat and the fuel-air mixture torch in which a quantity of air is mixed with the liquid fuel before projecting the fuel into the combustion supporting atmosphere. More particularly, it is sought 'to provide a pressurized fuel burner in which many be burned without objectionable types of liquid fuel can additives by reason depositing out of gums, resins or fuel v can be varied by the voperator to suit of the vapor-ization of the fuel and in which instant ignition is obtained by use of a fuel- 'r mixture that can readily be changed to pure fuel projection after a brief initial starting period without extinguishment of the flame, thereby avoiding objectionable depletion of the air charge in the pressurized fuel container. In accomplishment of this objective, the invention provides for heating of the pressurized fuel under thermostatic control as :the fuel travels -to the projection orifice, the heating under pressure being regulated so as to accomplish partial, but not complete, vaporization of the fuel, `thereby keeping gums, resins and fuel additives in the unvaporized liquid portion of the fuel that is carried along and projected through the nozzle orifice. The heat vaporized fraction of the fuel projected from the orifice into a combustion supporting atmosphere maintains combustion. The non-volatilized fraction of the fuel carrying gums, resins, additives and any other contaminants that would be deposited out if the vaporizable fuel were cornpletely vapor-ized, is burned in suspension in the atmosphere after leaving the nozzle orifice, and carbon deposition is eliminated.

After a short initial warm-up period, immediately following -the instant'ignition of the fuel-air mixture projected from the nozzle orifice, the supply of pressurized air to the internal mixing chamber can be stopped, the burner continuing in operation with fuel only being projected from the nozzle orifice, this projected fuel comprising a helter-skelter mixture of the volatilized or vaporized fraction and the non-vaporized (liquid) fraction referred to.

Another object is to provide a fuel burner in which the control of rthe fuel heating is accomplished by a thermostatic element, preferably-but not necessarily-under the direct inlluence of the heated fuel moving to the discharge nozzle orice. More particularly, it is sought to provide a thermostatic fuel heating control wherein one or more bi-metallic strips arranged to control the heating of the fuel are in direct heat exchanging relation to fuel llowing from a heating zone to the discharge nozzle orifice. As a specialized version of this aspect of the invention, the fuel heating one is provided by a member supported in the path of the burner llame, such member being formed [to provide a fuel passage that constitutes part of the fuel conduit leading from a fuel source, such as the bottom of the pressurized container, to the fuel discharge orifice in the nozzle. A suitable thermal responsive element, such as the bi-metallic strip or strips referred to is disposed in or adjacent that portion of the path of the fuel located between the heating zone member and the discharge nozzle. The thermostatic element is so arranged as to shift the position of the heating zone member in the burner ame in response to temperature variations of the fuel owing to the discharge nozzle. In this manner, the temperature of the fuel is maintained within a suitable temperature range which will effect partial, but not complete, vaporization of the fuel, all in accordance with the inventions objectives.

Another object is to provide a thermostatically controlled burner incorporating an adjustment for varying the heating control so that the temperature or temperature range of the fuel projected from the oriiice of the nozzle different fuels, different burning requirements, or different environment situations.

Another objective Vis to provide a burner of the fuel vaporizing type in which the fuel is traveled over a. path of relatively small cross-sectional area during heating and, after heating, the transfer of heat to or from the heated fuel, as by contact with heat absorbing surfaces, is minimized so that the projection temperature of the fuel is held close to the temperature to which it is heated 3 in the heating zone. Pre-determined or pre-set fuel heating temperatures are thus Vmaintained duringprotracted periods of torch operation, even thoughthe heavy sectioned metal components of the torch may vary in temperature over relatively wide ranges. -Acco'rding to this aspect oflthe invention, and as a specialized objective, the` discharge nozzle inwhich is `formed the fuel projection orifice is carried by a metal element of low heat conductivity which, although rigidly secured to achigh v fuel; cond-uihwhich conducts the partially vaporized fuel 'tothe projection orifice, the metal element which'carries the discharge nozzle is insulatingly shielded from surrounding heat conductive members by an annular insulat- 'ingair space. Y Y Y s Y s Another objective is concerned with the fuel heating vcomponent of a vapori'zing pressurized torchV and contemplates an arrangement in which the fuel is heated Ain a member mounted for yielding movement into and out'ofthe path of the torch llame, the mounting having `a high degree of flexibility so that movement of the heating -member `is readilyaccomplished as by means ofone or more bi-metallic strips with a high degree of sensitiv- :ity and accuracy in thermal response. In a specialized version of this aspect of the invention, the conduit for -the fuel Vtakes Athe form of 'a'helical corrugated thinwalled metal Ytube of the bellows type. The use of such a'tube in that portion of the fuel path extending from thefheating zonemember to the discharge nozzle permits "placement of a suitable thermostatic element, such as theV VYbi-rnetallic,strip or strips referred to, within the VcentralV passage of such `flexible bellows tube, blocking such pas- YVsage. Byrsuitable connections at theends of the corrugated bellows tube, the heated fuel is introduced Vinto th'e spiral passageY defined by thehelical corrugations of '1 the tube at one end of ther latter,V andows spirally about fthe bi-metalrorother thermostatic element along the {entire length of the latter. Thus, thethermostatic ele-Y ,rnentis, in elfect, wholly immersed in the heated fuel and completely subject to the temperature Vof the latter, so that accurate thermal response is obtain.

Y Another objective is concerned with the mountingof Y 4 Y scription is made in connection with the accompanying drawings forming a part of the specification.

In the drawings:

Fig. l is a fragmentary side elevational view, partly in section and with parts broken Vaway 'and removed, showing a-pressurized fuel .burning torch embodying kthe principle'sV 'of the Vpresent invention,v and incorporating a thermostatically controlled fuel heater, the fuel containingtank beingY largely omitted in this view;` ,v

Fig. |2 is a vertical sectional detail through the. mixing: block of the fuel burning torch of Fig. l, this view being enlarged with respecttoy that ligure to show the tubular inlet and outlet leads of the fuelheater and the fuel discharge nozzle and related parts; Y Y

Fig. 3 s a horizontal sectional detail through the mixing block of the fuel burningtorch of Fig.V 1, this view beingrtaken"substantiallypon the: line 3--3 VofFig. 1 and enlargedwithirespectto thatiigure; .Y f 1 41?ig.141 iwal-fragmentary detaiL-.partly in section, `and `'with lparts emovedsliowing'thefuel heating element of the torch, this view being taken substantially along a line indicated'at Hof-Pig; 'lf r Fig. V5 is Vajforeshortened fragmentarysectional` detail of fthe return. run of thelfuelheater comprising `a exi- -ble .corrugated metal conduit,k l.thisY viewA being.: enlargedl to `show the bi-metallic thermostaticwcontrol element and vthe kend connections for such flexibleconduit and being .takensubstantiallyA along thelne indicated at 5-5 of Fig.. 6 isV atransverse sectional detail through the ilexibler'conduit comprisingthe Yretuinruu of the heater, this view being.v taken substantially along zthe line indicated .Fig.i"7 f :is a transverse sectional detail A"taken vthrough the axis-tof the rotatable adjusting .member that varies the position and heating characteristicsof` the fuel heating element, the location ofA this `section being indicated at 7---7Y of Fig. 4-and being enlarged with respect to that iigure and also with respect to the other figures `in which the fadjustme'nt means is shown; e

5 :"Fig'. 8 is a fragmentary sectional detail showing the plug through which the pressurizediair is metered into vthe mixing chamber and the needle Vvalve by which the pressurized air supplyis shut off aftertheinitial Wa'rrn-up Y period; showing a fragmentary section of the mixing `block vandair'supply orifice, this .line 8Y-8of Fig. `3;`andy 'section y being taken .at

Fig. 9.is`V a fragmentaryfffront endelevational view of Y 'rthe torch,' takenl substantially' alongy the line 9j-9-.of

the Yfuel vaporizing heating component Vof a torch so to be readilyiaccessible for serviceand repair and yet vadequately-protected. from damage. The invention contemplates, in furtheranceof this objective, the placement ofthe fuel heater andithe associated fuelconductors and thermal responsive means outside,Y preferably below,-the

' f burning ltube of the torch, with the'heating zone member that moves into and out of theY flame path disposed at the prevent interference itheiame path. l .i .Y .l O ther objects and advantages pertain to certain novel with itsimovements' into and outof fieatures of construction and combinations and arrange- Yments of parts calculated to obtain a 'generally improved fuel burner-of the pressurized fuel burningtype, simple Vinidesign and construction, relativelyinexpensive to man- Y v.nfacture and readily serviced and repaired`in`the field,

' as become apparent from the following detailed i description of a suitable, embodiment Vrepresenting the best known mode ofY practicing the invention. This de- Fig. 1 and `enlarged with ,respect'to that-figure. Y

..'l'he'thermostatically'controlled fuel supplying and heat- .ing system` of the'present inventionf is usefulr'in many "applications in'fuel burning devices requiringran arrangement for pre-heating'the fuelV beforeV it is burned. v e One` of the nostuseful applications of lthe invention is `in concraft, and other fuels containingnon-volatilizable gums,

resins; additives or similaringredients.4 Sincethe pressurized fueLand air Ycan `be supplied to the mixing block and .chamber in various ways, such-as yfrom independent storage tanks or from the storage tank of avehicle and anairpump', the fuel and air source is indicatedgenerallytrat 1: and'here takes the `forni of a Vpressurized or vhe'metically sealed-tank andrelated parts described in `more detail in the referenced application. This tank may e be drawnor fabricated Vof steel or other suitable sheet metal and,` in itstop wall 2, isiittedrwith apump 3 by g meansjofwhich atmospheric air sfforced under pressure 'finto the-interior of thertank to provide the `desired pressures'l The pump is'Y removable .from its ,retaining ring Vor fer-rule in; rthe tank top'lto provide, a', filling :opening 'Il through which 'the fuel is'ntroduced into tank container l1 through the top wall 2. Air and fuel are led into mixing block 7 of the torch structure through a tubular coupling block 5 which is welded or`otherwise secured to the top wall 2 of Vthe tank over 'an opening therein, and a hollow plug 8 secured to the bottom face of the mixing block 7. The plug 8 is-externally threaded and screwed into the internally threaded upper end of the tank mounting block 5.

Mixing block The mixing block 7, of cast brass or bronze, is shown to be of rectangular or square section throughout the major portion of its length, having a reduced forward stub end 9 threaded externally to receive the internally threaded base end 1t) of a circular sectioned elongated burning tube 11.

The other, or rear, end ofthe block 7 is formed with an integral axial extension 14 of circular section, which has an axial bore 15 that guides stem 16 of the main control valve. This valve is turned by a thumb-wheel 17 which is fastened on the stem 16, the stem having a reduced diameter inner end 18 threaded'into a reduced diameter axial continuation of the bore 15. The tip of the valve stem 16 is formed with a reduced diameter cylindrical portion 19 that terminates in a conical tip 2t) which engages a mating seat 21 (Fig. 3) and thus serving to seal mixing chamber 22 from a reduced diameter passage 23 which is laligned axially with the valve stem and continuous with the mixing chamber. An O- ring 25 is received in an annular groove in the peripheral surface of valve stem 16 and engages the walls of the cylindrical bore 15 to seal the valve stem bore and prevent the loss of pressurized fuel and air out of the valve stem opening. Y

The mixing block 7 is formed with a transverse threaded bore 26 that receives and at its ends is sealed by fuel and -air metering plugs 27 and `28 respectively. The axis `of the bore 26 intersects the axis of the valve stem bore, the transverse bore being located immediately adjacent the conical valve seat 21 so that the central part portion 46 leads the air from the annular chamber 45 into 4an axial bore 48 of the plug 28. Like fuel chamber 36,y chamber 45 is sealed from mixing chamber 22 by the threadal engagement of air plug 28 with the axial bore 26.

- Air control The air metering plug 28 incorporates valve means Vfor regulating the supply of pressurized air to the mixing chamber 22. The valve here takes the form of a stem 50 turned -as by a thumbwheel 51 fastened on its outer end. The stem includes a thread portionSZ engaged in an internallyv threadedreduced portion of the bore 4S. The inner-end of the stem 56 is further reduced in diameter and terminates in a conical tip 53 that engages a frusto-conrical seat 54 to seal the plug passage 48 from a reduced axial 'orifice passage 49 thatopens into the mixing rchamber 22.

The radial metering passage 47 is exaggerated in size, being in practice of the order of about .03 to about .04 inch in diameter. The axial passages 39 and 49 in the fuel and air metering plugs may be about .031 inch in v diameter, the figures given for the various passages being representative of a suitable arrangement for a torch having a capacity of about 25,000' B.t.u. per hour, using a commercial Ygasoline type fuel.

The outer end of the axial bore through the air metering plug 2S is counter-bored to receive, as by a sliding t, the cylindrical portion of the stem 5@ to which the thumb-wheel 51 is xed. A deformable sealing gasket 56 embraces the stern and is compressed between the outer end face of an externally threaded guide extension 57 on the plug 2S and the bottom of a cap 58 that threadof the transverse bore between confronting inner end faces 29 and 30 of the metering plugs 27 and 28 deiines the mixing chamber 22 for the pressurized fuel Vand air. Fuel is led into Vthe mixing chamber 22 yfrom the bottom of the pressurized tank 1 through a supply tube 32 which may be of metal press-fitted or brazed into a socket 33 that opens through the bottom of the block into the interior of the tubular attaching plug 8. Abore 34 continuous with the tube socket 33 leads into the transverse threaded bore 26 at a point -removed from the mixing chamber 22. The opening of the bore 34 into the transverse threaded bore 26 is indicated at 35 Y(Fig. 3) andcommunicates with an annular chamber 36 surrounding a reduced portion 37 of the Ifuel metering plug 27, the threadal engagement of the fuel plug 27 with the axial bore 26 servesto seal the annular chamber from the mixing chamber 22. From the annular chamber 36, the fuel is led through a radial metering passage 38 in the reduced portion of the plug 27 into a central axial passage 39 of the plug. The radial metering passage 3S is exaggerated in size for clarity, it being in practice about .011 inch to about .02 inch in diameter. The axial passage 39 is closed at its outer end and at its inner end is formed with an opening located to direct fuel into the mixing chamber and against the reduced por-tion 19, or an adjacent frustoconical portion 40 of the valve stem 16.

Air under pressure from the tank or container 1 is led into the transverse threaded bore 26 at the end of the latter remote from the fuel inlet opening 35. The air enters the mixing block 7 through a drilled hole or bore 42, the lower end of which opens into the interior of the threaded plug 8 andthe upper end of which has an opening 44 that communicates with an annular chamber 45 surrounding reduced portion 4 6 of the air metering plug 28. A radial passage 47 (Fig. 8) in the reduced plug edly engages such guide extension.

Each of the metering plugs 27 and 28 is formed with an external'hex, or other non-circular portion, to receive a wrench for tightening the plug into the threaded tran..- verse bore or passage 26, the hex portions of the plugs providing circular radial shoulders that seat against the opposite side faces of the burner block 7 to seal the ends of the transverse bore 26. If desired, suit-able gaskets (not shown) may be disposed between the burner block and the hex portions of the plugs to insure iiui'dtight seals.

Fuel circuit and nozzle The fuel forced into the axial passage 23 of the burner block 7 from the mixing chamber 22 when the needle valve `cone 20 is backed away from the seat 21 is passed through a thermostatioally controlled heating device or element with which the present invention is particularly concerned. Atransverse bore 59, closed at its inner end, intersects closed axial passage 23, and provides a passage- Way to the receiving end of -a conduit 60, which is press tted or brazed into the counter-bored outer end of the bore 59. The tube 6G, which may take the `form of a standard soft copper tube of a nominal 1A; inch outside diameter, leads into the forwardly extending run of the fuel heating device or element indicated generally at 'I. The return run of the heating device terminates in another tubular metal conduit 61, which may also comprise a standard soft metal copper tube of nominal 1/8 inch outside diameter. This return conduit 61 carries the heated fuel to a nozzle support 62 mounted in an axial chamber 63 Aformed in the forward end of the burner block 7, the chamber 63 opening axially into the interior of the burning tube 11 at the base end of the latter.

To minimize conduction of heat to and from the fuel moving to nozzle 64, which is screwed into the bored and internally threaded outer end of the support 62, the support is formed of metal having relatively low heat conductivity, such as commercial stainless steel. T o further reduce the heat transfer between fuel moving to .the nozzle through the support `62, the support is mounted cantilever fashion in the chamber 63 by attaching t-hebase endonIyotthe support to the bottomof the recessthis" 'attachmentbeing eiected as by threading, Vpress fitting, 'or brazing. "In the arrangement shown, the burner'block 7 is formed with an axial socket that matingly receives'the 'i' Vend of the support 62so as 'tolocate the parts in assem bly: The Vsupport 62 maybe of crculargcross section, and mounted so its external surface is A,concentrito theinternal cylindrical surface of the reces s 63 vin the provision oan annular4 insulating airspace 65 Ythatcompletely surrounds thesupport. Y Y

v The` nozzle 64 includes a hex orother-Vrien-circ'ular` section' portion, intermediate its ends, to receive a wrench Y or.V other turning tool in screwing thegredueed. threaded n v. end 66 of the nozzle'into internally threaded'gounter- V4bore.,67 in the outer.A end ofg the supPOlL i axial bore 68 through the nozzle 64 opens through a relatively short axial extension ,69 havingdiameter about Yequal to length formed ontthefaceof the nozzle, the outlet ofthebore 678 ,constituting `the discharge orifice through which the ;,fuel;is Yprojected*'axiallyintothe interior ofgtheburning tube 'lLftThe return'v tube y61 ,fromf'the heaterexttends Vinto;the neem-63 of theburner body 7 through 'a lateral opening70 with surrounding insulating clearance andl isLV press tted, brazed or soldered into'A-azlateralsoclret71 fbored'in the supportf62." :The innerr endfofrjthisgsorcket intersects or otherwise communicates with an Yaxial bore or passage 72`tlxat is continuous withrthe nozzle; receiving counterbore 67. Y Fuel forced under pressure from the container 1 and rnixedywithirV in the chamber 22Vthus travels :first toV :and from* the heating device T and then Vinto the nozzle support 62, vfrom which' it isV projected into the interior of the burning tube 11 through thernozzle orice With- Yin Vthe tube V11, the mixture of Yfuel and air can be IignitedY '35 instantly without any initial primingjor wanning, this being one Vof the characteristics of the instant ame torch turned circular ange 77 which denes circularrrdischarge opening 78 at the extreme,Y forward'end of the burning tube. Y

' VFuel heating system t The heating deviceror means by which Yfuel .receivedY through thertubre 60 isheated and then returned tothe .structure .of theburner block 7 through the tube'AV A61 com- ,t

ipnises a suitable heater and asuitablethermostatic ele- Y n ment for regulating the fuel heating to maintain thettemperature of fuel owingrtorthe nozzlertrhrough the return Y tube 6,71l Within predetermined temperature Ylimits and'iu .a predetermined stateor condition. The heating may be accomplished lelectrically or in any othersuitable man- Y. ner, the device .of the present invention utilizing the heat v of the torch arne. The'heaterithus may comprise a helicalcoil80 of-4a metal -having high heat conductivitysuch as, lfor example, Vstandard vcopper tubing ofrapproximately t l/s inch nominal outside diameter.V This coil is mounted' Viuthe path of flame issuing from thedischarge outlet n 78 of theburning tube 11, the ,coil having -itsaxisapproximately parallel t the axis of the burning tube but dissV placed downwardly from such axis; To/irnproveY the heating action, a number of sheet metal vaues 81=are se'- 'cured, as by soldering or brazing, Yeach to an upper portion of one of the turns of the `helix Y80, these vanes being VYangled toward the source ofthe ame so as to deflect the flame toward and'against the tubing constituting the coil.

The two ends ofthe coil 80 are suitably connected, one

through'a heating zone member comprising the coil 80.`

BysuitableqgositioninfgiV ofV the coil 80V thefame path Y Vtheheiatingof the fuel passing through such'coilcan be regulated as desired tonobtainjnoptimumbllg :temper- 4a'fur ef',a11d optimum vapofiliationof Ythe'rfuel.,k Itis pro- 6 posed Vtosuhieet agthermal niotor,` such as abi-metallic strip or strips', to the inuence oiliquidtfuelfretrning to the burner blockassembly andthe .nozzle 64,?so'that such thermal motor, in response to 'temper'ature variations l of the returning fuel, Valters the position of the heater 10 coil`80 in Vaccordance with af predetermined pattern.

VVSincejtheV energy available tor effect movements of the fheatingcoil S0 -i'sdesirably held to a minimum, inrorder that-.the control canv have high sensitivity and fastinitial f action;I while; Yyetbeing.-simple, compact, inexpensive and light-Weight, the supply and return conduitsor tubes 60 Y`and 6L-are connected togeudsg84 andrSS of the'h'eater :tubel 80by ,exibleggthin-.walled nbellowstype metal tubes :82;:gand 83V respec'ztively.,V Eachfof thebellows tubes'SZ :and 83 is..corrugated'cpperthmuslwf tsflllgti; being formed with a continuous helical groove dening ja continuous helical ridge or crest.-,The ends'ofthebellofws tubes are receivedY telescopically within tubular socke'te'nd YVfittings `81 `aud Vare secured inplae as by. soldering or brazing'to provide.huid-tight; joiiitsY v'lfhis.attachment of the flexible bellows tubesgto, and between thejends of the copper tubes 60, 84,"and 61, 85.isV shown' in FigliV for the tube V83, it 'being understood thata similar arrangement is usedV for'the tube 82. Each titting 8.7 is in the shape of a Y; Y caporithimble, thelargejfopen end'of w l:|i ;hrreceivesV the 3DY iiexible tubing. YV-t'lh'e closed end of lthe iitting'is formed VVwith'V aV socket into which is securedrtheiend-of the apf imprime. supper;Y tubs?k or. Conduit, the fitting having a through opening placing the interior ofl one tube Vin cmmunication with ytl1e in terior,of the other.Y

'i jhermal moto'r Extending through the' passage within they con- Y -Y duit 83 yandv into the endV ttings STS a tll'erln'll'motor` comprising Ia' series of elongated bi-metal strips indicated V40 at 91,{92,p93, and 94.v V4These.strips'ma'y be ofthe type ,-sold by H; A. vWilson Company, Newark, Newflersey, under trademarlfMoi-ilex, each havingra thicknessof the order AVof 'about .015 finch.' The severalbifmetal strips are `disposed flatwise againstfoneanotherand Atheirle'dges aretrmmedto providelin theaggregatera substantially circular crosssection which substantially Viills'the clear Y Ainter-naipassage ofthe bellow'sptubing 83. I. By thusvlling j the center spacefin the flexible tubing, fuelentering the thermal ,motor tcornponent fof the heating. deviceY through the dischargetubeSS ofthe heater-,5 thisbeing theright- :hand end/rofrFigy5, iscau'sed tofflow'- over 'path of relatively/small 1cro'ssfsect-ional area.v By reason of the restriction in area of thebellows tube passage, the vflowing i fuel tends to follow the'helicalpathde'inedby, internal groovesgor 4channels 9S of theiiexible tubigl. The fuel thusy ows cicumferentiallyabout thebi-metallic f motor comprising the strips 9h94, as .welles longitudinally thereof, so 'thatY elective ftran'sferjof heat.v takes place between fuel and vthebi-rnetal,isti-ips. t yThus isl assured the thermal response ofthe `bi-metal.motor-,as anaccurate i indication of the temperature of the fuel discharged from the heater coil 80. A Y v `The movements of Vthe thermal motorv comprisingthe .fbi-metal `elements 91-94 occui'tin 'aplane which i1 Figs. 55 l, 2, and 5, parallels the plane ofthe drawings'and in 7Figs. 3V, 4,76, y'I ,aud-Sl is normal to theV plane of the drawfings. So thatrthe forcesY applied to the cantileyer heater structure by` the bi-metal motor strips arejconned to the verticalV plane Vmentionedfthe bi-metalstrips 917-94 are held against turning orrotation within the flexible tube 83v asrrby a presstt, or by suitable interloclisV (not shown) with theY end fittingsV 87. While the thermal Vrnet'ori is -illustratedaszan assembly of `a plurality fofrat bi-metal strips disposed tlatwise against onelanothenfit isjteasible, of course, toemploy a" fewer number cibi-'mtal 'stips Ythan shown, or other thermal responsive'means to eiect the movement of the heater 80 into fand out of the path of the torch flame. in the arrangement shown, it is desirable to secure the several lai-metal strips 91-'94 together as Iby brazing at one end, so they are readily inserted into and held within the tube as a unit.

It is one of the characteristics ofthe instant llame torch referred to that the fuel-air mixture leaving the chamber 22 is conducted wholly through passages of relatively small cross sectional area. `Apparently an undesirable separation of fuel takes place if the fuel-air mixture is passed through chambers or passages of large cross-sectional area. In the present torch, employing a circuitous path for the fuel between the mixing chamber 22 and the nozzle 64, precautions are taken to avoid the use offpassages of large cross sectional area. The -bimetal motor or strips 91-94 reduce the effective cross sectional area of the return run tube 83, as previously described, `and the interior of the ernble bellows-type forward run tube 32 is filled in a like manner with -a suitable material 96 (Fig. 7) such as braided wire, steel wool, or the like, to reduce its effective cross sectional area and to provide capillary passages for carrying the fuel-air mixture.

Although the fuel heater is shown as a specialized structure comprising a 1/2 inch diameter 5turn helical coil of copper tubing, it is apparent that other heaters can he employed. The flexible helical bellows- type tubes 82 and 83 may, for example, be parts of -a single U-shaped piece of such tubing, the bend of the U bing extended upwardly, so as to project into the path of the 'torch llame in substitution for, and replacement of, the helical coil 80.

In order that the fbi-metallic thermal motor comprising the strips 91-94 be responsive primarily to the temperature of the heated liquid fuel returning `to the mixing block 7 from the heater coil 80, the return run of the fuel conduit is insulated as by a spiral wrapping 97 of a suitable material, such as asbestos fabric or tape. The forward run of the fuel conduit comprising the flexible tube 82 is also covered by a wrapping of insulating material 98, which also may be asbestos fabric or tape. Thus the heating of the fuel is largely restricted to the heating zone member or coil 80 which is movable into and-out of the ame by the action of the thermal motor 91-94, even when the burner has become quite hot from long runs, and heat loss in return run S3 is limited when `the burner is in a cold condition, as when rstput in operation.

`As a further heat barrier to protect the fuel heater against radiant heat from the forward end of the burning tube 11 Iand as a stop to prevent contact of the uid conduits 32 and 83 with the burning tube, there is provided -a metal shield 100 interposed between the outer surface of the burning tube and the supply and return runs of the fuel heating structure or element, Although the shield 100 of stainless steel may extend the entire length of the fuel burning tube 11, it is satisfactory if it be restricted to the forward portion, say labout 1/a the length of the fuel burning tube, since it is such forward portion of the burning tube that becomes heated to the highest temperatures .duringoperation of the torch. rIhe shield 100 is concenric to the burning 4tube and has a circumferential extent suflicient to protect the fuel tubes v82 and 83 against the radiant energy from the sides as well as the bottom of the burn-ing tube. In the arrangement shown, the shield covers about 1/5 of the burning tube circumference. A pair of rspaced rivets 101 extend through the shield 100 and through the wall of the burning tube, suitable spacersA or washers being interposed'between the shield and the burning tube surface to hold the shield away from the surface of the burning tube in the provision of an insulating airspace and to permit the circulation ofl air therebetween,

l) Adjustment of thermostatc control At their rear ends, the supply and return runs of the fuel heater conduits are held cantilever fashion by a con1 bined supporting and adjusting structure, depending from the mixer block 7. This holding structure comprises a circular sectioned turning or yoke 102 of brass 'or similar metal screwed on a lfixed stud 109. The yoke includes a small diameter central portion -103 received between the fuel tubes 82 and 83. These tubes are engaged between an upwardly directed annular radial surface 104 and a downwardly directed annular radial surface 10S on the turning or yoke l102. Surfaces 104 and 105 and portion 103 Ythus define an annular relief or channel which receives the fuel tubes to cause them to move as the turning yoke 102 is rotated and caused to move axially along the stud 109 with Awhich it is threadedly engaged.

The stud 109 is screwed onto a threaded bore provided in the bottom of the mixer block 7. A lock nut 111 on the stud 109 may be tightened against the underside of the mixer block 7 to retain the stud in a preselected position. The adjusting yoke 102 is thus -heId firmly by the mixer block while being adjustable Vertically. This rotation is effected manually and the turning may be formed at its lower end with a relatively large diameter wheel portion having, say, a knurled periphery. Since the lruns or tubes of the fuel heating device are confined between the flat surfaces 104 and'105 of the adjusting yoke, the raising or lowering of the yoke has the 'effect of raising or lowering the forward heater coil 80 and thus Vvarying the position of the latter relative to the burning tube Ydischarge opening 78 through which the torch llame is projected. Raising the adjusting yoke and the fuel heating unit) has the effect of increasing the temperature to which the fuel is heated, whereas lowering the yoke (and the fuel heating unit) has the effect of lowering the fuel temperature. This adjustment is especially convenient in a hand-torch of the character illustrated, `which, by reason of its portability, will be used in various locations where fuel characteristics will vary and where the ambient atmosphere in which the torch is used will differ widely in temperature. For normal operation in a temperate zone, using commercial gasolene as a fuel, the adjustment is eected so as to maintain a temperature of from about 280 F. to about 340 F. when the fuel is supplied under a pressure of from about 25 pounds to about 60 pounds per square inch gauge. More desirably. the temperature is held in the neighborhood'of about 310 F. at a pressure of about 40 pounds per vsquare inch gauge, this mode of operation producing partial, but not complete, vaporization of the fuel so that, while'the flame is maintained, thereis no objectionable deposit of gums, resins, or additives within the narrow'passages of the heating element, nozzle support or nozzle. In the torch mentioned, operating under the conditions referred to, the diameter of the ori/- lice in the nozzle 64 is about .016 inch diameter.

i `Shroud chamber portion .116' to accommodate the tubes 82and `33 of the fuel heating element. The shroud' is generally larger than and spaced outwardly from the burning tube, providing a clearance 117 between the outer surface of the burning tube and the inside surface of the shroud, this space being approximately 1A: inch in radial dimension in the hand torchillustrated. The sheet metal tube =against the opposite sides' of the burning tube in the provision' of attaching tabs 119-that are secured to Vthe tube Sides Vby screws `120. Theforward'portion ofthe shroud thus-supported cantilever lfashion bythe screws 120, theqshroud having a forward edge 122 defminga front 'openingthatY lies in.a"verticalY plane beyond or ahead Beneath the burning tube, the edges of the sheet metal comprising the shroud tube Vare secured together as byy a lapped joint indicated at'1 21.V The side portions ofthe shroud .are formed'with Yintegral anges'bentftoward one another-across the front of the fuelfheating element and secured together ,inVV a lapped joint124, theseflange portionsproviding a frontal wall-125 Yonthe shroudf` The bottom wall of the shroud-'is spaced sufficiently below the bottom of the burning tube: to permit full v'ertical` YVmove-ment of thefuel heating elementtubes A82. and-.83 which may be deilected as to the broken line position of I iig. l bythe-thermal motor in withdrawing the heater f. coil 80 fromthepath of the torch flame, or substantially s o. ,Thus, the shroud 115 .may be of non-uniformfsec- -tionj along `its,lengthandqthechamber portion 1116 that accommodates the tubes 82 kand 83 of the Vfuel heater may be -relatively shallowat its rear end and relatively deep at'theforward end immediately below.Y the heater -780, where the greatest deflection or amplitude-of moveement of the fuel heater occurs. f Q

f Circulation ofeair throughthe shroud 115 is induced by pressure reduction at the forward end of the burning tube resulting from the Vblast of the torch ame and, desired, supplemental openings may be provided inV the shroud, such as opening 126 in the bottom of the shroud immediately rbelow the heaterV coil 80. Thus, air may be drawn into the shroud chamber through the bottom opening 126, as Wellwas through bottom rear lopening 127 through iwhichextend the tubes 82 and 83 and arcuate openingl28 into clearance space V117. Y

'7"1 ""Operiztorth'; A the operation of the thei'niosta'ticallyy controlled `burneroescribed, the tank or container 1 is first chargedv f, with the desired liquid fuel, such as standard gasolene,4

` kerosene, jet engine fuel, ory the like,A and then air is pumped into the tank over the space above/the fuel. This proyidesfthedesired pressurized air chargepthat serves notV Vonly to forcepthe liquid fuel into and tlu'rough` the fuel 3 heating systemL and out the nozzle 64, but^al so (suppliesV` x Acombustionv 'duringVY theA warm-upf period. With the needlevalve`53 backed off its seat to'admit pressurized air from the containe zor tank to the mixing chamber l 22 .under the proportioning conditions provided by they i fueland airfmetering. passages 38 and 47 Virrtheplugs 27 and V28 respectively, ythe main control valvev ZQ-is backed voff-.the seat21, deiining the loutlet opening from the mixing chamber to admit the fuel-air mixture intolthe mixing mblock ypassageZl through which thel mixturerflows into.

,'the intersectingrpassage 59 andthence into the supply tube 'of the fuel heatingdeyice or element. The fuel v advances from the supply tube t50 Y through the;forward Q ,run 82 into theinlettubedof ythe heater SIL From the heater, the fuel enters V,the return 'run .8 3. through ther heater discharge tube-85,; andifrom Vthe'returnjrun `83' thefuel is'led into the nozzle .support passagej. through Y ,the. retrn.conduit 61. Eromrthereturn conduit Vtil, the .;fuel isV conducted pthrough thepassage 72V into the bored j area 67, thencethroughthe passage V68 ,irt thef'nozzle'i and projected from the end outlet' opening of the passage 68, which constitutes the projection orice, into the combustion chamber defined by the burner tube 11;

' VThe fuel-air mixture thus projected from the passage '68 into thecombustion chamber is in a condition which permits immediate combustion and immediate torch use. Itis ignited by inserting a match or .the like through one uof the large holes 75 in the burning tube or through the opening 78 in the end of the` burning tube. Fuel passing Vthrough the heating coil 80, located directly in the path of the ame, when the system is cold, immediately begins to heat and vaporize. YAs the fuel is thus vaporized in the heating coil 80 at yan increasing rate, the mixture being projected from the orificeV 68 progressivelyincreases in fuel vapor content. As the percentage ofY fuel vapor increases, the quantity of air required to be prefmixed'with the fuel progressively decreases, and the operator may adjust thumb-screw 51 to gradually close the needle valve inner conetip 53 againstv the seat 54 of the air control Ivalve. When therate of vaporization'has reached the dc- .sired operational level, the` air'control valve 53 may be completely closed and the burner will continue in operation as a fuel-vapor burner. A few strokes of the pump 3 recharges the tank with air to replace that 'consumed during the short wann-up period. As the temperature .of the fuel leaving the heatingcoil 80 approaches 'the desiredrange, and, consequently, the point of maximum desired vaporization, the bi-metallic motor elements 91-94 become heated and cause exible conduit 83 to bend and move the heating coil 80 downwardly away from the axis or center of the torch flame generated in the combustion chamber. As the elements 91-94 cool, the coil 80 will, on Vthe other hand, move toward the torch llame axis, thus holding fuel temperatures within preselected limits.

YWhile the principles of thepresent invention have been described in conjunction with a portable torch, the in- Vvention maybe Vapplied to pressure stovesV designed Ato burn liquid hydrocarbon fuels 'bearing Vnon-vaporizable additives or elements and to other types Ofbumcrs for projection-combustion of fuels of this type, A liquid'fuel burner has thus been described which is capable of producing instantaneous heat andof producing heat from a burner of the fuel-vapor type without air being pre-mixed with the fuel once the burner has reacheda predetermined level of operation. A control' elementi has also been provided which, through adjusting means and. a thermal motor, permits partial, but not complete, vaporization of liquid fuel, so that standard hydrcarbon'liquid fuels can be employed without objectionable deposits ,of gums, resins,.or other non-volatiliza`r leY fractions or additives being deposited out or left behind in the relatively narrow passages of the fuel vaporizing system.

In accordance with Vthe patent statutes, the principles of the Vpresent invention may be V'utilized'in various ways, numerous modifications fand alterations Y. being contemplated, substitution of fparts and changes in 'construction being resorted to as desired, it being understood that the embodiment shown in the drawings'and described above tainer for holding Va supplyof fuel and a charge of air under pressure, a metal block formed to define a mixing chamber, means dening separate passages throughwhich fuel and air are conducted under pressure from the 'supply container to the mixing. chamber, a combu'stiontube,

-anozzle havingaanoriiice throughl which fuel is projected into Ythe combustion tube, means locatedgexteriorly Vof the combustion tube defining affuel passagefrom the Vmixing'chan'iber to the'nozzle a'rui'including` aliest exaccueils 13 changing element, means supporting the heat exchange element in heat exchange relation to the torch ame resulting from ignition of projected fuel, and thermal responsive means in direct heat exchange relation to and subject to the temperature of fuel in a portion of the fuel 'passage between the heat exchange element and the nozzle' arranged automatically to vary the heat exchange relation to control the heating of fuel traveling through the :fuel passage in obtaining a substantially constant condition in the projected fuel.

2. In a liquid fuel burner of the type comprising means defining a mixing chamber into which fuel and air are projected under pressure to form a pressurized combustible mixture, valve means governing the projection of air into the chamber to vary the fuel-air ratio of the mixture, lmeans defining a jet orifice through whichthe pressurized mixture is released, means defining a combustion cham- `ber to receive the mixture released from the orifice and having a discharge through which flame and combustion products are projected, means defining a passage from the g chamber to the jet orifice, said passage including a 'portion defined by a tube of high heat conductivity metal, 'means supporting said tube portion in the Vpath of hot combustion products projected from the combustion chamber discharge, and means responsive to the temperature of the mixture having operative connection with the tube portion supporting means to alter the position of such tube portion relative to the projected hot combustion products, whereby automatically to maintain the condition ofthe released mixture within predetermined limits.

` 3. In a liquid fuel burning structure of the type comprising a body member formedwith an internal chamber to which liquid fuel is supplied under pressure and a hollow nozzle mounted on the body member and having an Voutlet orice through which the fuel is discharged under pressure to burn as a torch ame upon ignition, conduit means for conducting fuel under pressure from the chamber of the body member to the nozzle, said conduit means including a heater to condition fuel owing to the nozzle, -the' heater being exposed to the heat developed in a torch llame from the nozzle, and thermostatic means immersed in and in direct heat exchange relation to heated fuel 'flowing to the nozzle from the heater, said thermostatic means automatically varying the exposure of the heater in response to changes in the temperature of the fuel flowing to the nozzle to maintain a predetermined condition in fuel discharged.

4. 'In a liquid fuel burning structure of the type comv'prising a body member formed with an internal chamber to which liquid fuel is supplied under pressure and a hollow nozzle mounted on the body member'and having an outlet orifice through which the fuel is discharged under "pressure to burn as a torch flame upon ignition, avheating element located outside the body member, conduit means connecting the heating element to the chamber of the body member and to the nozzle for serial ow of fuel under pressure from the body member chamber to the heating element and from the latter to the nozzle, the heating element being arranged so as to be heated by the heat developed in a torch flame from the nozzle to condition fuel flowing to the nozzle and supported for movement relative to the nozzle and such a torch llame, and thermostatic means operatively connected to the heater and disposed in heat exchange relation to heated fuel "owing from the heater to the nozzle, said thermostatic means being adapted to effect such movement of the heater in accordance With temperature changes of such heated fuel in governing the heating of the heating element in response to the temperature of the fuel moving to the A"to which liquid fuel is supplied under pressure and a hollow nozzle mounted on the body member and having an outlet orifice through which the fuel is discharged under pressure to burn as a torch llame upon ignition, conduit means for conducting fuel under pressure from the chamber of the body member to the nozzle, said conduit means including a plurality of flexible sections and a heater section substantially wholly supported by the flexible sections in the noimal path of a torch ame from the nozzle to absorb part of the sensible heat of such llame and thereby heat and partially vaporize the fuel being conducted to the nozzle, and adjustable supporting means forv the flerdble sections of the conduit means whereby to alter the position of the heater section relative to such torch flame to vary the ratio of llame heat absorbed by the heater section of the conduit means to the total heat of the torch ame.

6. In a liquid fuel burning structure of the type comprising a body member formed With an internal chamber to which liquid yfuel is supplied under pressureV and a hollow nozzle mounted ou the body member and having an outlet orifice through which the fuel is discharged under pressure to burn as a torch flame upon ignition, conduit means for conducting fuel under pressure from the chamber of the body member to the nozzle, said conduit means including a heater section and exible support sectio-ns, at least one of the support sections being fast to the body member, the heater section being substantiallyvwholly supponted by the support sections in the normal path of a torch flame from the nozzle to absorb part of the sensible heat of such flame and thereby heat and partially vaporize the fuel being conducted to the nozzle, and means having connection `with the conduit means and responsive to the -temperature of heated and partially vaporized fuel acting automatically to alter the position of the heater section relative to such torch flame whereby to vary the ratio of ame heat absorbed by the heater section of the conduit means yto the total heat of the torch flame.

7. In a liquid fuel burning structure of the type coinprising a body member formed with an internal chamber to Awhich liquid fuel is supplied under pressure and a hollow nozzle mounted on the body member and having an outlet orifice through which the fuel is discharged under pressure to burn as a torch flame upon ignition, conduit means-for conducting fuel under pressure from the chamber of the body member to the nozzle, said conduit means including a heater section and exible support sections, at least one of the support sections being vfast to the body member, the heater section being substantially wholly supported by the support sections in the normal path a torch flame from the nozzle to absorb part of the sensible heat of such flame and thereby heat and partially vaporize the fuel beingy conducted to the nozzle, and a thermostatic element located in direct heat exchanging' relation to heated and partially vaporized fuel in one of .the flexible support sections, said thermostatic element being responsive to an increase in temperature of such fuel ito'act automatically to shift the conduit means to alter the position of the heater section lrelative Ito such torch dame whereby to vary the ratio of dame heat absorbed by the heater section of the conduit means to the total heat of the torch llame.

8. In a liquid fuel burning structure of the type comprising a body member lformed with an internal chamber to which liquid fuel is supplied under pressure and a hollow nozzle mounted on the body member and having an outlet orifice through which the fuel is discharged under pressure to burn as a torch llame upon ignition, conduit means for conducting fuel under pressure from the chamber of the body member to the nozzle, said conduit means including a heater section and exible support sections, at least one of Ithe support sections being fast to the body member, the heater section being substantially wholly supported by the support sections in the normal path of a torch flame from the nozzle to absorb part of the sensible `heat of such flame and thereby heatV and partially vaporize the fuel being conducted to the nozzle, means having connection with the conduit rugated tubel constraining l`the fuel the'spiral groove. Y Y v 10. Ina liquid fuelburning structure ofthe type comcorrugaticns whereby toconstrain jl cumferentially Vin the spiral groove.V

Y whereby to vary the ratio of ame heat absorbed by the heater section of the conduit means to the total heat of the Vtorch arne, and means connected between the con- I duit means and the body member and actuatable manuv ally for'shifting the heater section relative to such torch ame to. adjust the relation betweenthe heater section and'the torch ame. e i 9. In a liquid fuel burning structure of the type comprising a body member formed with an internal cham- .be'r torwhich Yliquid fuel is supplied under pressure and a hollownozzle'mounted on the body member and hav- Ying an outlet orifice through which the fuel is discharged chamber'of thelbody member` tothe nozzle, said con- 'qduitneans including a heater V'section disposed in the/path voa torchlame fromthe nozzlegand a ilexible section tion to restrict the thermostatic element to temperature -eects` resultingffrom fuel in the .one exiblesupport section. l Y `f` 'i Y 1 V12. A liquidfuelburnercomprisinga supportingstruc- Y"ture, a nozzle carried by the supporting structure-'means supplying fuel to the nozzle under pressure to project the fuelg-fromthe-no-zzle as a spray for ,burninginthe form of ajtorch ame; the Ifuel supplying means including 'aconduit throu'ghiwhichlthe fuel travels Von its `way` to the nozzle, said conduit having a heater-section locatedin a position that is offset laterally relative to the nozzle "Vsoas 'to be" subject to a portion of thevheart4 of the torch flame Itoheat the traveling fuel, and means disposed Y, under pressure to burn as a torch llame upon ignition, conduit means4 for Vconducting fuel under pressure from the connectedf'betweenthe body member-and theheatersec-s tion to permit shifting of the heater section into and Vout V'ofthe torch flame, the flexible section comprising a crorrugated'tub'e having a continuous spiral internal groove,

"and an element extending through the center-'of the corto new circurnferentially` prising a body member formed with an internal chamber ft iwhich liquid fuel is supplied'runder pressure andra 'hollow nozzle mounted on the body member and having s outlet oricc through which the fuel isV discharged n under pressure to burn as a torch ame upon ignition, Y conduit means fornconducting fuel under -pressure from theA chamber of the body member to the nozzle, vsaid conduitmeans including a heater section disposed in the pathiof a torch flame from the nozzle and a flexible sectiofn connected between Ithe body member and the heater sectionto permit shifting Vof theV heater section -into and 'out ofthe torch name, the exible section comprising a corrugated tube having a continuous spiral internal groove, a bimetallic strip extending through the center of the corrugatedY tube indirect heat exchanging relation vto l-fu'elY flowing therethrough,isaid strip beingY characterized by bending Vin one direction during an increase and inY another directionrduring a decrease in'its temperature thereby to eiect corresponding bending of the'corrugated tube and said shifting ofthe heater section, and said strip being in, contact with therinternal surfaces ofthe tube the fuelnto ow cirsupport sections, .at least one of the support sections being fast tolthebody member, the heater section being substantially Wholly supported by the support, sections in the normal path of' a torchv ame from the nozzle to absorb part of the sensible heat of such ame and thereby Y VY heat and partially vaporize the fuel being conducted to i Vthe nozzle, a thermostatc element located in direct heat exchanging relation toheated'and partially v aporized 1 fuel inone Yof the flexible support sections, said thermostatic element being responsive to an increase in temperature of such fuel to act automatically to shift the cond ,l duitgmeans 'to Ialter the position kof fthe heater` section l relative to such'torch kame wherebyV to vary'lthe ratioY Lof ame heatY absorbedY by Vthe heater section of the Y K conduit meansrrto the total heat of Vthe torch a'meyand Y insulation embracing said one @exi-ble support se "in direct heat exchange relation to'and responsiveto the Ytemperature ofthev fuel traveling in the v'conduit between the heater section and the nozzle automatically varying `the'@heating oflfth 'heater sectionY by -thegtorc'hilame in 'p-ccordance with' temperature' changes Vin suchlast mentioned travelling`A fuel to maintain the lfuell supplied to the nozzle atV a substantially constant-predeterminedltemfper'at'ure.-fv a 1;' 'i 135A' l unitary readily portable ,liquid fuelV` burning structure' for vaporizable lilydrocarlionV fuels," saidy strucl ture comprising in combination .a tank adapted to contain 'asupplyv ofliquid fuel anda volume ofl compressed` air above thefueLa body,` member inountedfon` thetank v landformed with an internal chambennieans providing separate passageslfor conducting fuel and air under pres- 'su'rc from the interior of the tank to the chamber in said fbodymember, 'anoz'zle carried by theA chambered body member and formed ivith'anoutlctoriice .through 'whichl chamb'ered body member and connected; to` the 'outside VVsectionsY of theconduitlmeans to'support the latter with (the heater section positioned in -thei pathV of the torch ame, said last,` named meansbeing Vadjustable to shift the position ofthe heater section -relativevftolthe torch ame whereby to'vary the heat absorptionof fuel flowing through such heater sectioninj'regulating.theydegree of fuel vaporizationY tofprevent'- overheating 5 -oft-hel fuel and carbonization. f- =i af- 14. The method of-burning liquidzghydrocarbon'fuel having nonvaporizing constituents in la fueljburner of the the" fuel is' discharged'tofburn as agjtorchameflwhen ignited, whichV method `comprises` conducting the fuelgto the nozzlel under pressure substantially `continuously at substantially a constant *rateV ,and overl a' 1 predetermined Y path, discharging ltheifuelifroin,thenozzleprice igniting theldischargedr fuel to produceY 'afsteady torch flame, exposingrthe :fuel-in one portion of said path Atothe heat VVof the torch'ame to heat Yand effect partial vaporization oflthe fuelas it is conducted tothe nozzle, andcontinuously regulating the exposure .of `the fuelato the torch flameheat in response to thetemperaturerof the heated Yand partially vaporized fuelto Ymaintain ther-.temperature Vof thefuel ybeing discharged Vwithinipredetermincd e Y l5; Themethod Vof burning (liquid hydrocarbonrfuel havng-nonvaporizing constituents in a fuel burner of the type having 'a-nozzle formed with an porice through i, Vwhich the fuel isV dischargedto burn-as;I al torch flame when ignited, which Vmethodcomprisesecondllctinlg the fuel to the nozzle under pressure substantiallycontinu- YouslyV at substantially a constant'rate'and overl?, predeter- Vruined path,V dischargingfthefuel Yfro-inthe nonleuoriica 'igniting the discharged vfuel-'ltd produceia; steady; torch flame, exposing the fuelV in'one portion of saidzipath to `vaporization of the fuel as Vit is conductedto the lnozzle,

the heat of the torch ame to ,heat and eiectpartial exchanging relation to a heat responsive element in another portion of the fuel path, and continuously regulating the exposure of the fuel to the torch flame heat in accordance with the response of such element to maintain the temperature of the fuel being discharged Within predetermined 16. The method of burning liquid hydrocarbon fuel having nonvaporizing constituents in a fuel burner of the type having a nozzle formed with an orice through which the fuel is discharged to burn as a torch flame when ignited, which method comprises conducting the fuel to the nozzle under pressure substantially continuously at substantially a constant rate and over a predetermined path, discharging the fuel from the nozzle orice, igniting the discharged fuel to produce a steady torch flame, passing the fuel as it is conducted over one portion of the predetermined path in direct heat exchanging relation to the steady torch tiarne to absorb a fractional portion of the heat of such ame to heat and effect partial vaporization of the fuel, and continuously regulating the heat exchanging relation solely in response to the temperature of the fuel in another portion of such predetermined path to vary the ratio of the flame heat portion absorbed to the total ame heat, whereby to maintain the temperature of the fuel being discharged within predetermined limits.

17. A portable torch for vaporizing and burning liquid hydrocarbon fuel, said torch comprising a sealed container for holding a supply of fuel under pressure; a combustion tube; a nozzle having an orifice through which fuel is projected into the combustion tube; means defining a fuel passage from the container to the nozzle and including a heat exchange element adapted for fuel flow therethrough; means having connection with the container, with the fuel passage dening means and with the nozzle, supporting the heat exchange element in heat exchange relation to a torch llame resulting from ignition of fuel projected from the nozzle; and thermal responsive means directly subjected to the temperature of fuel in a portion of the fuel passage between the heat exchange element and the nozzle and operatively associated with the support means and the heat exchange element arranged automatically to vary said heat exchange relation in response to the temperature of the fuel in said last mentioned passage portion to control the heating of fuel travelling through the fuel passage in obtaining a substantially constant condition in the projected fuel.

18. ln a liquid fuel burner, a body member, a nozzle supported by the body member in xed relation, said noz- 21e being adapted to receive fuel under pressure and having an orifice through which fuel is discharged to burn as a torch flame upon ignition, a fuel vapor control element comprising conduit means adapted to conduct fuel under pressure from a fuel supply tank to the nozzle, said conduit means including a heat absorbing portion and a exible connecting portion, the heat absorbing portion being continuous with and supported by one end of the connecting portion and disposed in the ame path to heat and partially vaporize fuel owing therethrough to the nozzle, the other end of the connecting portion being held in fixed relation to the body member and connected to the nozzle to deliver fuel to the latter, and a thermal responsive element carried by the flexible connecting portion of the conduit means in heat exchange relation to fuel owing through the latter, said thermal element bending in response to changes in its temperature and being adapted to effect simultaneous bending of said exible connecting portion, whereby such bending of the connecting portion varies the position of the heat absorbing portion in and relative to the ame path automatically to adjust the heating of fuel iiowing through said heat absorbing portion in response to the temperature of fuel in the flexible connecting portion.

19. In the process of burning as a torch liquid hydrocarbon fuel having vaporizable and non-vaporizable constituents which comprises conducting the fuel under pressure along a predetermined path of relatively small cross sectional area having heat conducting walls to a projection orifice, continuously discharging the conducted fuel from the orifice into a combustion supporting atmosphere, igniting the discharged fuel to produce a steady torch ame, and heating by conduction through such walls and vaporizing the fuel in said path and by said flame before the fuel is discharged, the improvement which comprises automatically moving the conductive walls deiining the fuel path laterally relative to the direction of the torch ame and relatively into and out of such flame to vary the heating to vaporize a portion only and to prevent complete vaporization of the vaporizable constituents whereby the unvaporized vaporizable constituents constitute and until discharged are maintained as a liquid vehicle entraining the non-vaporizable constituents and preventing depositing of the latter as a residue along said path.

20. The improvement in the fuel burning process as defined in claim 19 wherein the varying of the heating is thermostatically effected.

References Cited in the file of this patent UNITED STATES PATENTS 595,994 Culver Dec. 21, 1897 752,137 White Feb. 16, 1904 780,752 Hill Jan. 24, 1905 813,494 Franklin Feb. 22, 1906 835,627 Loring Nov. 13, 1906 965,136 Gierth July 19, 1910 1,093,249 Bowling Apr. 14, 1914 1,138,165 Wirth May 4, 1915 1,216,115 Hauck Feb. 13, 1917 1,236,172 Holmgren Aug. 7, 1917 1,265,210 Kahn May 7, 1918 1,283,133 Flitcroft Oct. 29, 1918 1,402,747 Doble Jan. 10, 1922 1,546,038 Smith Iuly 14, 1925 1,612,883 Porteriield Jan. 4, 1927 1,861,877 Quill June 7, 1932 2,097,771 Nelson Nov. 2, 1937 2,111,239 Elze Mar. 15, 1938 2,204,294 Blanchard June 11, 1940 2,285,720 Joy June 9, 1942 2,294,421 Ray Sept. 1, 1942 2,299,749 Howard Oct. 27, 1942 2,355,693 Aldrich -n Aug. 15, 1944 2,362,259 Findley Nov. 7, 1944 2,456,864 Cole Dec. 21, 1948 2,463,830 Tullis Mar. 8, 1949 2,465,572 Bramming Mar. 29, 1949 2,467,450 Wollner Apr. 19, 1949 2,473,192 Blackwell .lune 14, 1949 2,580,113 Martiri Dec. 25, 1951 2,625,211 Hill Ian. 13, 1953 2,780,280 Allen Feb. 5, 1957 FOREIGN PATENTS 720,722 France Dec. 12, 1931 OTHER REFERENCES General Chemistry (Timm), published by McGraw- Hill, New York, 1950 (2nd ed.), page 350, last line, page 351 rst six lines and pages 352 to 354 relied on.

Images