US1773418A

US1773418A - Liquid-fuel torch

Info

Publication number: US1773418A
Application number: US352691A
Authority: US
Inventors: Thomas C Wilson; Roy J Petty
Original assignee: Liquid Fuel Cutting & Welding
Current assignee: Liquid Fuel Cutting & Welding; Liquid Fuel Cutting & Welding Torch Corp
Priority date: 1929-04-05
Filing date: 1929-04-05
Publication date: 1930-08-19
Anticipated expiration: 1947-08-19
Also published as: DE551676C; FR682650A

Description

Aug. 19, 1930. 1'. c. WILSON ET AL 1,773,418

LIQUID FUEL TORCH Filed April 5. 1929 2 sheets-sheet 1 llllllllllllll wir unulgln ATTORNEYS ug. 19, 1930. Tl c;l w|| s0N ET AL Y 1,773,418

LIQUID FUEL TORCH Filed April 5.71929 2 Sheets-Sheet 2 Y A A 1111111111. 1111 r11. n n L Patented fitug. 12, 5.23

THOMAS Cl WILSGN, OF BROOKLYN, A`ND ROY J. PETTY, 0F NEW YORK, N'. Y., ASSIGN ORS T0 LIQUID FUEL CUTTING- & TELDNG TORCH CORPORATION, OF-NEW YORK,

1v. Y., a coaroaarrou or New YORK 'LIQUID-FUEL TORCH Application illedApril 5, 1929. Serial No. 352,691.

This invention relates to torches of the type in which a combustible mixture of fuel 'and oxygen is burned with the generation of high temperature. More specifically, the present invention is concerned with a torch in which liquid fuel, such as gasoline, is employed, the liquid being vaporized in the torch and a mixture of the vapor and oxygen produced` and burned at the usual tip. The -new torch is primarily adapted for cutting purposes and an embodiment of the invention for that use will be illustrated and described, though it is to be understood that the principles of the invention may likewise be employed in torches for welding and other-heating puroses. y p While numerous attempts have been made in the past to construct torches in which a vaporized liquid is used as the combustible` these torches Ihave not proved satisfactory. Their failure in operation 'may be due to various causes, but the primary reason for their lack`v of success is undoubtedly due to improper vaporization of the liquid and mixture of the vapor with the oxygen. Also in such torches,

some eii'ort' has been made to-preheat the oxygen before it mingles with the vapor, but this result, which'is highly important to successful operation, has not been achieved.

The torch of the present invention has lbeen constructed to overcome the defects of prior torches of this typeand in it the liquid fuel is subjected to a high vaporizing temperature and is directed through thezone of Vaporizing heat under such conditions that practically complc're xvaporization isaccomplished with the result that no fuel in liquid form enters the chamber where mixture with the oxygen is brought about. The oxygen is also conducted to the mining chamber in such manner that it takes up a substantial quantity of heat in the vaporizing Zone and thus when it is mingled with the vapor, there'is produced a combustible mixture at high tem perature which i's led at once to the burner tip for consumption. The mixing of the vapor .extending between the blocks.

5 The new torch includes many novel features of construction which will be best understood from consideration of the accompanying drawings7 in which Y F ig. 1 is a longitudinal section ofa cutting torch embodying the present invention;

Fig. 2 is a view of the torch in side 4elevation with parts cut away;

Figs. 3, 4, 5, 6, 7, 8, 9, 'and 10 'are sectional-views on the lines 3-.3, 44-4, 5 5,

includes a block 21 at its rear end, a second block 22 at its front end and a metal shell 23 Extending through the block 21 are

passages

24, 25, the inner walls ofthe passages at the outer'end of the block 21 being threaded. Mounted in the threaded end of the passage 24 is a nipple 26 which can be connected to a line leading to a suitable supply of oxygen, while threaded in the end of the passage 25 is a gate valve 27 for controlling the iiow of liquid fuel, such as gasoline, from a suitable container maintained under pressure. A strainer 28 is inserted in the opening at the end of passage 25 and held in place by the valve 27. p

A pipe 29 extends from the block 21 to the. block 22, this pipe being in communication with the passage 24. Formed in the block 21 is a cross passage 30 communicating with the passage 24, this cross passage leading te a pipe 31. Flow through the cross passage is controlled by a needle valve 32, the stem of which is threaded into a bushing 33 mounted in the block 21. Packing 33 surrounding the stem of the valve and held in place by a suit able nut makes the valve gas-tight.

A pipe 31 seated in the block 21 passes through a suitable opening `inthe block 22, this pipe carrying a sleeve 34 on its upper end soy arrangement being such that by turning the collar 38 the pipe 35 may be moved endwise, the

gland

34, 36, 37 permitting such movement While preventing the escape of gas. Oxygen flowing into passage 24 enters the pipe 31 through the side passage 30 under control of the needle valve 32 and flows through the pipe 31 to the pipe 35. Oxygen ilowing linto the passage 24 also enters the tube 29 leading to the head 22.

-The block 22 is provided With a transverse passage 40 in communication with the pipe 29, this passage leading to a chamber 41 in the block in which is mounted a valve 42. This valve is forced against a seat at one end of the chamber by a spring 43 held in place by a nut 44, the valve having a stem 45 which extends through passage 46 in the block 22 and out through the wall of the block, a nut 47 and packing 48 preventing escape of gas around the stem. The passage 46 communicates through a transverse passage 49 with a tube 50. The valve 45 is operated by a linger piece 51 pivotally mounted on aV pin 52 carried in vaportion of the block 22, the depression of the finger` piece unseating the valve and permitting flow from pipe 29 to `pipe 50. The pipe 50 extends through the block 39 and through a similar block 53 to the burner head 54 Where the end of the pipe 50 is in comlmurication with a passage 55 in the burner Liquid fuel liowing through the valve 27 passes through passage 25 and into pipe 56 which is enclosed Within a pipe 56 of larger diameter which acts as a re-inforcement for the small pipe 56. The pipe 56 has a closure plate at each end between which plates pipe 56 is welded in position, the plates then being drilled for the openings of pipe 56. The pipes extend from block 21 through

blocks

22 and 39 to block 53, Where pipe 56 vconnects With passage 57. Mounted in block 53 is a tube 58 extending therefrom to burner head 54 where the end of the tube is mounted on a boss 59. Within the tube 58 is an inner tube 60 in the surface of which is cuta spiral groove 61, this groove connecting at its lower end with passage 57 in block 53, so that liquid fuel flowing through the pipe 56 passes through the passage 57 and into the spiral passage defined lv the groove 461 and the inner wall of the tub 58. The spiral groove 61 is cut in the Wall .if the inner tube 60 in such manner that there are substantial lands 62 between adjacent convolutions, these lands lying in contact with the inner wall of the tube 58. At the upper end of the inner tube 60 the spiral groove leads to a circumferential channel 63, and openings 64 drilled through the bottom of the channel lead to the interior of the tube 60.

The oxygen pipe 35 extends through the inner tube 60 and fits the inner Wall of the tube snugly, although it is free to be moved lengthwise by the adjusting collar 38. The

.oxygen tube atits free end is tapered, as indicatedat 65, to a line orifice and the tapered end of the oxygen tube enters a chamber 66 in the boss 59. The end Wall of the chamber 676 is so formed that the end of the oxygen tube may be seated against it and the end of the tube and its seat in the chamber cooperate to provide a means for controlling the flow of the combustible to the burner head, since the combustible must pass through the chamber 66 between the tapered end of the tube and the Wall of the chamber on its Way to the burner head through the passage 67. Oxygen passing out ot the nozzle end of the tube 35 also flows into the passage 67 to the burner head, the shape of the parts being such that the flow of oxygen into passage 67 induces with it combustible entering the chamber through openings 64 in the inner tube 60.

The burner head 54 is provided with an expansion chamber 68 to which the passage 67 leads and threaded into the rear wall 'of the expansion chamber is a tube 69, the passage through the center ot the tube communicating With the passage 55 for oxygen used for cutting purposes. The tube 69 projects out through athreaded boss 70 at one end of the burner head on which boss is mounted a burner tip 71, the outer end of the tube 69 being channeled as indicated at 72 (Fig. 5). These channels cooperate with the inner surface of the burner tip 71 to provide a plurality of orifices for the combustible mixture. Thel tube 69 has a squared portion 73 which vlies outside of the burner chamber, this the combustible mixture from the mixing chamber 68. The tip is so positioned that the flame issuing from it strikes against thci outer Wall of the tube 58.

Vhen the torch is in operation, oxygen flows through the passage 24 and thence through a transverse passage 3() and through the needle valve 32 to the tube 31, passage 30 and through the needle valve 32 to the tube 31, passing from this tube to the tube Liquid fuel, such as gasoline, is admitted through the valve 27 and flows through the tube 56 and thence through the spiral passage passage, the flow of liquid fuel is to some extent restricted and as the fuel flows around and around through the spiral passage it is brought repeatedly under the flame issuing from the tip 76. This flame results from the combustionof gasoline vapor and oxygen and is, therefore,`at a high temperature, and the repeated passage of the liquid lthrough the hottest part of the vaporizing Zone insures that all of the liquid will be vaporized. The vapor continues through the spiral passage to the circumferential channel 63 and then through openings 64 into the chamber 66 in the boss 59. Oxygen flowing through the pipe 35 issues from the nozzle end 65 and passes through the chamber 66 and into passage'67 where some mixing of the oxygen and fuel vapor occurs. The mixture flows then into the annular chamber 68 in the burner head where expansion takes place, resulting in a thorough intermingling of the vapor and oxygen.

-This mixture flows out of the burner head and into the burner tip issuing from the channels 72 to be consumed in the ordinary way. Oxygen for cutting flows through the tube 29 4and the-nce into the tube 50 under the control of valve 42. The oxygen enters the passage 55 in the head and then flows through the tube 69 to issue through the central opening 77 at the tip.

' It willl be seen that in this torch complete vaporization of the liquid fuel is assured hyreason of the use of the spiral passage which causes all of the liquid to be subjected to the hottest part of'the vaporizing flame a number oftirnes in its flow to the burner head. The use of a passagevof this type prevents a direct flow of the liquid past the Vaporizing flame, particularly when the torch is operated in a position in which the burner head is below the handle.

In numerous prior torches, -With which we are familiar, the liquid is conducted through a straight annular passage to the burner head, this passage being defined between an outer tube and. an inner tube for oxygen. Frequently asbestos or like material is placed in this passage. The presence of the asbestos is highly objectionable because it quickly becomes clogged` up and in addition carbonization is likely to occur within its pores'. Also, since the preheating or vaporizing flame bears against one side of the tube, only that portion of the liquid which flows against the surface where the flame is playing is highly heated. Liquid which flows through a part of the passage out of contact with the preheating flame is not raised to the same degree of heat and as a consequence, the liquid may be only partially vaporized at the time it enters the burner head.

In the present torch, the inner tube 60 is in direct contact with the inner wall of the outer tube 58 and heat taken up from the preheating flame is taken up by the inner tube and passes back through the metal to the tube 35 which fits the interior of tube 58 snugly. The heat is thus conducted from the flame to the oxygen Valong a path of metal and it raises the temperature of the oxygen flowing through tube 35 to a high degree. In prior torches with which we are familiar, the preheating of the oxygen has not been successfully accomplished because there is no metal path along which the heat may flow from the preheating flame to the oxygen. On the contrary, in those torches where the liquid flows through the annular passage surrounding the oxygen tube, the only heat which is transferred to the oxygen must be conducted through the liquid itself or through its vapor. The presence of asbestos in the annular passages1in these prior vtorches also serves no useful purpose in the transfer of heat, because of the low conductivity of this substance. In such torches, therefore, the oxygen is not raisedto a high temperature, because it is .effectively shielded from the pre l heating flame either by the liquid fuel or by the asbestos through which the liquid fuel is flowing.

Instead of conducting the liquid fuel through the vaporizing zone along a spiral path, other methods may be employed, such, for example, as that shown in Fig. l2. In the construction there illustrated, the tube 58 sur-` rounds a tube 78 in the outer wall of which is cut a channel' 9 which extends from the block 58 nearly to the circumferential channel 68 atv the forward end of tube 78. The passage 79 then turns back upon itself to conduct fuel rearwardly through the channel 80 which communicates with another channel 8l which conducts the fuel forwardly to the circumferential groove 63 whence it passes through openings Gil-into the chamber 66. The tube 78 is so positioned that the channels 7 9, 80, and 8l extend directly through the Zone where the .flame from the tip 76 is playing upon the outer surface of the tube 58. The walls of the passages defined by the inner surface of the tube 58 and the channels in the tube 78 form a hot plate over which the liquid fuelflows to be rapidly vaporized. In the. construction shown in Fig. l2, heat is trans` ferred from the preheating flame through tube 58, tube 78 and oxygen tube 35 to the oxygen, a metal path thus being provided by the heat transfer.

Instead of employing an inner tube, such as those designated 60 and 78, a coiled tube 8l, such as that shown in Fig. 13, `rnay be employed. This coiled tube is mounted at one end vin the block 53 and at the other in a boss 82 extending from the burner head 54.

cumferential channel 84 through which are formed openings 85 leading to a chamber 66. The convolutions of the tube 81 lie closely in contact with the outer wall of the tube 35 and also Contact with the inner` wall of the tube 58 so that in this construction also, heat from the preheating iiame is conducted by ly between the tube 35 and tube 66.

The torch is preferably made of brass, the parts being secured together by brazing or the like. For example, the tube 56 is brazedf at one end in the block 21 and at the other end in the block 53. Similarly tube 50 is brazed at one end in the burner head .54, and at the other in the block 22. This construction is used throughout the torch whenever appropriate.- Packing glands are also used wherever required as, for example, a gland nut 86 is'threaded into a suitable opening 1n the end of the inner tube 60 and bearsI against packing 87 wwhich prevents leakage backwardlv between the tube 35 and tube 66.

Among the important features of the new torch are the several control devices. It will be seen that the flow of oxygen to the cutting jet is controlled by the valve 42 and the supply of oxygen for combustion is con# trolled by the needle valve 32, this needle valve making it `possible to obtain a line degree of control of the oxygen supply for heating purposes. The fuel consumed 1n the new torch is under control both as a liquid and as a vapor. The fuel in liquid form passes through the gate valve 27 before it enters the torch and this valve may bev adjusted to provide a rough control. The fine control of the fuel supply is provided by the valve formed by the tapered end of the oxygen tube 35 and its seat in chamber 66. This valve controls the fuel in vapor form and by moving' the tube.35 endwise by means of the. adjustment collar .38, an exact regulation is obtained.

4The oxygen tube 35 is moved by, regulating means ,disposed outside of the passage for the fuel vapor, and the vapor which enters the chamber 66 Hows into the passage 67 around the outside of the nozzle end of tube.

35, without restriction except that provided by the parts constituting the valve. It is important that there should be no threaded mounting for the oxygen tube near the burner head because at this point the parts are subjected to great heat and where a threaded Yneath the vaporizing flame under such conlditions'that perfect vaporization is obtained. In torches in which the liquid passes through ti gases in the envelope bustible mixture` is supplied to the preheating or vaporizing tip, variations in pressure are likely to cause the dame from this tip to be extinguished, Aand whenever this occurs operations must be discontinued and the preheating iiame reignited. In the present torch, variation in pressure in the burner head is eliminated so that the preheating iame continues to burn practically indefinitely unless extinguished by drafts or the like. In order to overcome this difficulty, an igniter in the form of an asbestos cord 88 or the like is mounted in a suitable clamp 89 on the tube 58 near the burner head, the clamp lying out ofl the zone of vaporizing temperature. The cord extends beneath the tip in such manner that it is maintained at high heat by the preheating flame and should the flame be extinguished, the cord will cause it to ignite again immediately.

Since the successful operation of the torch ldepends on proper vaporization of the liquid fuel and the preheater dame mu;t continue burning at the `roper rate throughout the use of the torch, 1t is important that'the preheater ti 76 be constructed to provide a flame ,oft e required size and that this flame should be protected against the wind. In the present torch, the tip is constructed to accomplish these results. This tip may take different forms, three of which are shown in Figs. 14, 15, andl. As illustrated, the tip includes'a stem 90 provided with threads 91 by which it can be mounted in the opening in the boss 75, the stem having a shoulder 92 with fiat sides by which the tip can be engaged by a toolfor insertion Aor removal.

In the tip as shown at Fig. 14, the stem is bored to provide a passage 93 lengthwise of the stem. This passage terminates close to the rear end and at this end is a fine openin 94.. The passage 93 extends to a point beyon the shoulder 92 and within the end 95 of the tip, the passage increases in diameter, as indicated at 96. The portion 96 extends partv way through the end 95 and leads to another portion 97 of still greater diameter.- With this arrangement, the combustible mixture which flows through the passage 74 enter the tip through the fine opening 94 througl which the gas passes under `considerable pres sure. In the passage 93 the gas` expands and at the end of the passage 93 the llame begins.

The hot burning gases` then expand in the

portions

96 and 97 and the length of these portions is such that under normal operation, the cone of the dame does not-project beyond the end ofthe while the burning suchv parts of the l menare hollow end of the tip as are not filled by the cone, the envelope spreading out beyond the end of the tip to impinge upon the Surface of the tube 58. l

In Fig. 15 a'slightly modified construction is illustrated, in which the stein 90 has a passage 98 through it, this passage being connected to the open end 99 of the tip through a passage 100 of line diameter. The open end 99 of the tip is enlarged in diameter in three stages designated 101, 102 and 103 respectively. With this arrangement, the cone of the flame appears to begin at the point where the stage 101 is connected with the stage 102, the cone lying `Wholly within the chamber at the end of the tip, so as to be protected by the tip Walls.

In Fig. 1 6, the stem 90 has a line opening 94 at its rear end and leading forward from this opening is a passage 104 of somewhat increased diameter.` This passage opens into a chamber 105, the cross-sectional area of which gradually increases as the extreme end of the tip is approached. This construction is quite similar to that shown in Fig. 15 except that the chamber increases in diameter gradually instead of by steps. In any of the tips illustrated, the gas flowing from the burner head flows through an orifice of small diameter beyond which the gas is'allowed to expand. In each tip the cone of the preheater llame is protected to a substantial extent, the cone projecting .either to only a slight extent or not at all beyond the end of the tip, While the envelope around the cone fills the space at the end of the tip. Tips of the construction illustrated have been found in practice to be highly efficient and to give excellent results due to the fact that the tip can be extinguished only with great diculty.

By reason of the metal path for the conduction of heat from the preheating zone directly to the oxygen flowing through the tube 35, both ingredients of the combustible mixture delivered to the burner head enter the expansion chamber in this head at a high temperature which is conducive to most efiicient conditions of combustion at the end of the burnerl tip 71.

The tube 56 has a relatively fine bore, the crosssectional area of which is substantially the same as the cross-sectional area of the groove 61 in the tube 60 at the end of the tube remote from the burner head. The groove 61 preferably is formed so as to have an increasing cross-sectional area as the burner head is approached, thus providing space for the expansion of the vaporized fuel. The crosssectional area of the groove and of tube 56 is so fine that it has been found in practice that back-fires in the groove and tube are practically impossible. Since the tube 56 is of small diameter it is encased within the outer tube 56 which 4serves asa stiifenmg een- directing a flame against a Wall of said passage, and a metallic path for conducting heat from said flame to oxygen in the pipe.

2. In a liquid fuel burning torch, the combination of a preheater tip receiving a combustible mixture, an oxygen pipe, a passage lying outside the pipe, the flame from' the tip impinging upon a wall of the passage, and a pathway of heat-conducting material arranged to receive heat from said ame and conduct it to the oxygen. 3; In a liquid fuel burning torch, the combination of a preheater tip supplied with a combustible mixture, an oxygen pipe, a burner head with which 'the tip communicates and to which thelpipe leads, and means for conducting fuel to the head, said means being arranged to lead all of said fuel through the zone of temperature developed by a flame from said tip.

4. lIn a' liquid fuel burning torch, the conrbination of a preheater tip providing a vaporizing flame, a mixing chamber, an oxygen pipe leading thereto, and means for conducting Vfuel to said chamber, said means causing all the fuel to pass through the zone of temperature developed by said iameron its yyay to said chamber.

5. In a liquid fuel burning torch, the combination of a preheater burner providing a vaporizing flame, a mixing chamber connected to said burner, an oxygen pipe leading to said chamber, and means for conducting fuel to said chamber through the zone of temperature developed by said flame, said means conductin all the fuel through said zone `along a single tortuous path.

6'. In a liquid fuel burning torch, the combination of a preheater burner providinga vaporizingwflame, a mixing chamber connected to said burner, an oxygen pipe leading to said chamber, and means for conducting fuel to said chamber through the zone of temperature developed by said flame, said means including a metallic heat-conducting pathway explosed at one end to said fiame and conducting eat to oxyg'en in said pipe.

7 In a liquid fuel burning torch, the commounting permitting endwise movement of the tube toward and away from its seat.

9. In a liquid fuel burning torch, the combination'of a burner head, a passage leading thereto, the Wall of the passage forming a valve seat, an oxygen pipe having a tapered end adapted to cooperate with the seat to form a valve, a preheater burner in communication with said head, al passage for fuel communieating through said valve With said first passage,'\the fiame from said burner playing on a Wall of the fuel passage, and a mounting for the `pipe at a distance from its tapered end, this mounting affording a means ,lfor adjusting the opening of said valve.

' 10. 'In a liquid fuel burning torch, the c0m. bination of a burner head, a mixing chamber therein, a second chamber spaced from the first and connected thereto, the Wall of the second chamber being formed to'provide a valve seat,'an oxygen pipe movable endwise and having an end lying Within'the second chamber, said end cooperating with said seat to form a valve, a passage for fuel leading to said second chamber, the fioW thereof' from the second chamber being controlled by said valve, and means engaging the tube at a distance from said end for moving the tube end- Wise to open and close the valve. A

11. Ina liquid fuel burning torch, the combination of a burner head, a mixing chamber therein, a second chamber spaced from the first and connected thereto, the Wall of the second chamber being formed to provide a -valve seat, an oxygen pipe movable endwise and having an end lying within the second chamber, said end cooperating with said seat to form a valve, a passage for fuel leading to said second chamber, the flow thereof from the second chamber being controlled by said valve, threads carried by the tube at a distance from said end, and a block having a threaded wall engaging said threads, rotation of said tube causing endwise movement thereof to open and close the valve.

12. In a liquid fuel burning torch, the combination of a burner head, a tube leading thereto, an inner tube within said first tube, saidv inner'tube having a channel formed in its outer surface which channel is closed by the inner Wall of the first tube, a passage in the burner head connecting with one end of the channel, a mixing -chamber to which the pasclosed by the inner `Wallof the first tube, a

passage in the burner head connecting with one end of thechannel, a mixing chamber to which the passage leads, a vaporizer burner communicating With saidmixing chamber and directing a flame against said first tube adjacent said channel, means for conducting liquid fuel to' said channel to be vaporized therein by said fiame, and a tube Withinsaid .inner tube for conducting oxygen to said mixing chamber for mixture therein With the vaporized fuel. i

14. In a liquid fuel burning torch, the combination of a burner head, a tube leading thereto, an inner tube Within said first tube, said inner tube having a spiral circumfereniial channel formed in its outer surface which channel is closed by the inner Wall of the first tube, a passage in the burner head connecting with one end of the channel, a mixing chamber to which the passage leads, a vaporizer burner communicating with said mixing chamber and directing a flame against said first tube adjacent said channel, means for conducting liquid fuel to said channel to be vaporized therein by said flame, and a tube Within said inner tube for conducting oxygen to said mixing chamber for mixture therein With the vap'orized fuel.

15. In a liquid fuel burning torch, the combination of a tube, a second tube Within the first and having a channel in its outer surface which channel is closed bythe inner wall of the first tube to forma passage, a pipe extending through said second tube, a burner head to which said first tube is con- .'nected, said head having a chamber into which the end of said' pipe projects and said for fuel' against one wallof which thefiame from said burner impinges, said passage leading ail of said fuel through the hottest part 0f pendent of said oxygen passage for transferthe zone of temperature developed by said flame, and means for mixing oxy en with the fuel vaporized by said flame amid supplying said burner with a part of the mixture.

17. i In a liquid fuel burningtorch, the combination of a passage for liquid fuel, a passage for oxygen adjacent thereto, a burner for directing a flame against the `Wall of the fuel passage to vaporize fuel flowing therethrough, and heatconductive means indering heat from said flame to saidoxygen.

duit for oxygen forraising the oxygen to substantially the same tem erature, means for mixing the vaporized fuel and heated.l

oxygen, and means for supplying said mixture to said vaporizingmeans.

In testimonywhereof We aiiix ourA signa- 18. In a liquid fuel burning torch, the combination of a passage for liquidvfuel, a passage for oxygen adjacent thereto, a burner for directing a flame against the vWall of the fuel passage to vaporize fuel flowing therethrough, means for A mixing the IVaporized fuel and oxygen, and heat conductive means independent of said oxygen passage for raising the temperature of the oxygen approximately to the temperature of the vaporized fuel prior to the mixing thereof.

, 19.. In a liquid fuel burning torch, the combination of a passage for liquid fuel, a passage for oxygen, means for vaporizing the liquid fuel, means receiving the vaporized fuel and oxygen and mixing them, and heat conductive means independent of said passage for oxygen for raising the temperature of the oxygen substantially to that of the vaporized fuel before the two are mixed.

20. In a liquid fuelxburning torch, the combination of a conduitV for liquid fuel, a conduit for oxygen, means for vaporizing the liquid fuel, heat conductive means independent of said conduit for oxygen for raising the temperature of the oxytgen substantially to that of the vaporized uel, and means for mixing the 4vaporized fuel with the oxygen.

21. In a liquid fuel burning torch, the combination of a conduit for liquid fuel, a conduit for oxygen Within said fuel conduit, burner means for vaporizing the liquid fuel, heat conductive means independent of said conduit for oxygen for raising the temperature of the oxygen substantially to that of the vaporized fuel, means for mixing the vaporiz'edv fuel with the oxygen, and means for supplying the mixture to said burner means.

22. In a liquid fuel burning torch, the combination of a conduit for liquid fuel, a conduit foi` oxygen Within said fuel conduit,

means for vaporizing the liquid fuel, heat conductive means independent of said conduit for oxygen foi` raising the'temperature of the oxygen to a temperature substantially the same as that of the vaporized fuel, and means for mixing the vaporized fuel and heated oxygen in regulated amounts.

23. In a liquid fuel burning torch, the com# bination of a conduit for liquid fuel, a conduit for oxygen-Within said fuel ronduit, means for vaporizing the li uidpfuel and heat conductive means iudepen ent of said con- CERTIFICATE OF CORRECTION.

Patent No. 1.773,418. Granted August 19, 1930, to

THOMAS C. WILSON ET AL. I

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, lines 126` to ,128,

strike out the words and comma "passage 30 and through the needle'valve 32 to the tube 31, page 4, line 8, strike out the syllable and words "ly between the tube`35 and tube 66" and insert instead metal from the flame to the oxygen; and

vthat the said Letters Patent should be read with these corrections therein that the same may conform4 to the record ot' the ease in the ,Patent Office.

Signed and sealed this 7th day of October, A. AD. 1930.

M. vJ., Moore, (Seal) y Acting Commissioner of Patents.