US2683484A - Portable blowtorch and the like - Google Patents

Description

LuA. FALLIGANTI PORTABLE 'BLOWTORCH AND, THE LIKE Filed Oct. 50, i950 July 1 3, 1954 4 Shee'ts-Sheet 1 aflbrneyy J y 1954 L. A. FALLIGANT v PORTABLE BLOWTORCH AND'THE LIKE I 4 Sheets-Sheet 2 Filed Oct. 30. 1950 L. A. FALLIGANT PORTABLE BLOWIZOR'CH AND THE LIKE July 13; 19 54 4 Sheets-Sheet v4 Filed Oct. 50, 1950 ALMA JINVENTOR. 01115 fi/fijdnl Patented July 13, 1954 UNITED STATES PATENT OFFICE PORTABLE BLOWTORCH AND THE LIKE Louis A. Falligant, Madison, Wis., assignor to Prepo Corporation, Edgerton, Wis., a corporation of Delaware Application October 30, 1950, Serial No. 192,915

13 Claims. 1

This invention relates to small portable torches and the like utilizing self-pressurizing inflammable liquid fuels in replaceable expendable cartridges.

The invention primarily applies to a blowtorch construction utilizing such fuel cartridges, al-

fuel to vaporize unevenly, i. e., the lower fraction or butane content having the lower boiling point though several features of the invention are ap- 5.;

tends to evaporate first leaving the pentanes of higher boiling point and which will not supply adequate starting gases at normal room temperatures.

The present invention centers around a combined construction with such a fuel cartridge whereby the gaseous fuel supplied to the burner is always of substantially the same composition. This has a very substantial advantage in maintaining constant burner efficiency without repractical to throw away the cylinder when 5 operations by avoiding explosive mixtures of fuel and air within the container. The cartridge contains a low pressure fuel which enables the use of lightweight thin-walled inexpensive containers of sufiicient capacity for satisfactory blow torch operations. Such a fuel cartridge has been described and claimed in copending application Serial No. 46,917, filed by the present inventor on August 30, 1948, now abandoned in favor of application Serial No. 324,890, filed on December 9, 1952, as a continuation-in-part of said earlier application.

' The fuel employed in the cartridge is a hydrocarbon blend of butane and pentane in liquid form blended together in such a manner as to be substantially free from undue separation of from 38 to 85 F., under atmospheric pressure conditions, the amount or proportion of vaporization of the constituents varying with a change in temperature within the range so that 38 F.'is .the initial boiling point for the blend and 85 F. is the final or end boiling point for the blend.

Such a fuel raises certain problems in burn- .ing when in containers of reasonable capacity Jifor blow torch use due to the tendency of the quiring an operators frequent adjustment of airfuel ratios to assure eflicient operation. Less expensive burners can be employed without provision for air variation and the desired burner temperature is always present. Since the fuel is always of constant value the problems encountered of varying fuel quality as in gasoline torches are avoided.

In carrying out the invention the liquid fuel is Withdrawn in liquid state from the fuel cartridge and the vaporization zone is maintained in the passage leading to the burner whereby all fractions of the fuel are vaporized simultaneously and the gas is then passed to the burner where it first encounters air entering through fixed air ports to provide a substantially constant fuel-air ratio designed for the most efficient combustion of the specified fuel.

The manual manipulation of the torch by grasping of the fuel container by the operator remains important in cold Weather to assure a proper pressure within the container for the discharge of liquid fuel therefrom. For stoves and other burners the fact that the cartridge may be grasped by the hand and generally warmed prior to its assembly in the stove tends to provide the desired initial pressure.

Additional problems of providing adequate gaseous fuel at the burner for starting without the heat priming usually accompanying the gasoline torches have been solved by the present invention by employing valve means that initially limits the flow of liquid fuel to the torch for starting with a blue flame and thereafter opens wide to full torch on position.

The invention avoids dangers arising from. the use of excessive fuel pressures since the pressure head within the fuel cartridge or container is maintained nearly constant.

Where quick action and substantial heat is required, the invention employs a regenerative type of burner in which the fuel passage is heated by the burner on its way to the fuel orifice or port in the burner. Other means of utilizing burner heat for fuel vaporization are provided 3 by a special passage construction to give greater heat input to the fuel in the vaporization zone.

The accompanying drawings illustrate the invention as applied to a blow torch structure and which constitutes the best mode presently contemplated for carrying out the invention.

In the drawings:

Figure l is a perspective view of the torch in substantially side elevation;

Fig. 2 is a similar view showing the several assembly parts exploded in non-assembly;

Fig. 3 is an enlarged detail view of the bottom clamp and torch support showing its operation;

Fig. e is an enlarged detail view showing the cartridge holder in vertical central section and with the cartridge and valve assembly in elevation and partly in section;

Fig. 5 is an enlarged fragmentary central section through the upper end of the cartridge showing the closure construction;

Fig. 6 is a top plan view of the cartridge of Fig. 4;

Fig. '7 is an enlarged detail central section through the valve assembly;

Fig. 8 is an enlarged detail central section through a modified form of valve assembly;

Fig, 9 is an enlarged detail central section through the burner assembly;

Fig. 10 is an enlarged detail central section through a modified form of burner assembly;

11 is an enlarged view partly in section of the lower end of the burner tube showing the filter construction; and

' i-ig. i2 is an enlarged partial View of the throttle valve of Fig. 7.

The torch comprises, in general, a cartridge holder or shroud assembly I adapted to have a fuel cartridge 2 assembled therewith, a valve assembly 3 and a burner assembly 4.

The cartridge holder or shroud assembly I comprises a circular base 5 hinged at one side to a vertical strap 8 extending rigidly down- The above fuel has a vapor pressure not exceeding 38.6 pounds per square inch, absolute, at a temperature of 100 F., and the fuel is classified for transportation and handling purposes as an inflammable liquid, and not as a liquified petroleum gas. The blend and composition may vary so long'as the self-pressurizing characteristics of the fuel do not take it into the ranges of liquifled petroleum gas classifications by safety and regulatory bodies and thereby subject the torch and the fuel cartridges to laws and regulations that prohibit the practical use of the same. By staying within the inflammable liquid class, and keeping the cartridges within a certain size .it is possible to provide a practical torch.

The distillation range for the fuel is from about 38 F. where approximately no distillation takes place to about 85 F. where 100% distillation is reached. Intermediate temperatures provide different percentages of distillation or evaporation according to the temperature.

The fuel is known as a self-pressurizing low pressure inflammable liquid, and its pressure range follows a curve from zero pressure at 38 F. to about twenty-five pounds per square inch at 100 F., about sixty-five pounds per square inch at 150 F., about one hundred thirty-five pounds per square inch at 200 F., and one hundred seventy pounds per square inch at 220 F. At this pressure the safety closure of the container is designed to blow off and release the contents.

The fuel is loaded as a liquid into the can at temperatures below 38 F. to avoid any pressure problem in loading and any tendency for leaking fuel gas. The loading is done with automatic equipment wherein a top metal cap I2 is applied over the open top of the can I I.

wardly from an upper circular shroud I secured to the valve body 3, and a second vertical strap '8 hinged at its upper end to the shroud I on the side opposite strap 6 and having an inwardly extending spring clamp end 9 adapted to lock t se 5 against the bottom of a cartridge 2,

The vertical straps 6 and 8 generally follow the side contour of the cartridge 2 and leave the major portion of the cartridge exposed for grasping by the hand in manipulating the torch.

The clamp 9 is connected to strap 8 by a reverse bend in the strap and which snaps the strap tightly in place when assembled with base 5 and with a cartridge 2 in place.

The base 5 has a recess I0 in one side disposed to receive the clamp 9 when the latter is man- 'ually closed beneath the base and cartridge.

The holder I is quick to operate in securing a cartridge in place and in releasing the cartridge.

The cartridge 2 comprises a metal can I! designed to withstand a fuel pressure as high as about three hundred pounds per square inch, which provides a high factor of safety for all normal operating conditions.

The fuel in cartridge 2 is preferably a blended butane-pentane fuel of approximately the following composition:

Per cent by weight Normal butane 52.3 Isobutane 2.2 Isopentane 43.5 Normal pentane l 2.0

Cap W has a curved metal rim I3 adapted to fit over the rolled rim I4 of the can II and to be sealed therewith by a cap gasket I5 disposed and compressed therebetween.

The cap I2 has a body extending downwardly within can H with its side walls crimped outwardly at It beneath the rolled rim I4 to hold the cap in place.

Cap I2 also has a central opening with an upstanding neck fiange I'I into which a grommet is of neoprene or the like is compressed and secured.

Grommet I8 has an enlarged inner end into which the upper flanged end of a dip tube I9 is secured, and an enlarged upper outer end with a circular central recess 20 extending downwardly from the top and connected to the upper end of the dip tube I9 by a slit 2I axially of the grommet. Slit 2| is normally closed by the compression of the central portion of the grommet in flange II.

The grommet I8 is of a freeze-resistant neoprene or other suitable resilient sealing material which will heat soften at approximately 200 F. and blow out of cap I2, thereby constituting a safety release for can II. The fuel employed is such as to release relatively quietly at this temperature and the corresponding pressures and without explosive effect, whereas if it were permitted to rise to three hundred pounds per square inch gauge pressure the can I I might explode violently. Such considerations are desirable where a cartridge 2 of fuel might accidently be disposed in a fire. Since the cartridge never contains a combustible or explosive mixture of fuel and air there is substantially no danger when the cartridge bursts or the cap I2 blows out, and should a leak occur at room'temperature the vaporization would be so slow in the open atmosphere as to present very little danger.

The material of grommet [8 should be of high resilience and toughness and preferably low in sulphur content to prevent any tendency of the grommet to tear at the upper edge of flange H.

For the purpose of bleeding liquid fuel from the can a dip tube I9 extends to the bottom of can i I and has its inner end open at one corner of the can so that it can be kept in the liquid fuel to nearly the last drop of liquid in the can.

The cartridge 2 is adapted to be filled to approximately three-quarters of its volume with liquid fuel and to retain the fuel under pressures corresponding to temperatures encountered in storage, transportation and handling. Only in the event of emergencies apart from normal usage, such as an external fire heating the cartridge to above 200 R, will it release its contents.

The valve assembly 3, which is adapted to be assembled with a fuel cartridge 2, comprises a metal body 22 having a downwardly extending circular flange or skirt 23 adapted to receive the outer head of grommet I8 and to seal thereagainst, an upwardly extending circular flange 24 threaded on the outside and adapted'to be coupled to the burner 4, and a laterally extending circular flange 25 threaded internally and externally and adapted to receive the stem 26 of a manual valve 21.

The body 22 carries the bleeder device '28 centrally of skirt 23 and adapted to enter downwardly through grommet l8 into dip tube 9 for the release of fuel to the valve 21 and from thence to the burner 4.

The bleeder device 23 consists of a hollow tube open at the top end and closed at the bottom end except for a small side inlet port 29 near the bottom end. The tube 28 is carried vertically in a plug 36 fitting tightly upwardly inside skirt 23 and is of sufficient downward length to enter axially through grommet I8 separating the material thereof at slit 2| and to dispose inlet port 29 within the upper end of dip tube l9.

The plug 30 has a oircurnferentially grooved tapered shank 3i extending downwardly about the hollow tube 28' and adapted to enter recess 20 in the top of grommet l8 and to seal against the head of the grommet by expanding the same outwardly into pressure engagement with skirt 23.

The shroud l is secured upon lower skirt 23 between a shoulder 32 of the body 22 and a nut 33 threaded upon the skirt so that the cartridge '2 is securely held in sealed relation to the valve body.

The valve assembly 3 is sealed to cartridge 2 at three points: (1) where tube 28 passes through slit 2| in the region of cap flange i1, (2) where skirt 23 confines against the outer circumference of the outer head of grommet l8, and (3) where tapered shank 3| enters the top of grommet l8 and seals thereagainst.

Once a fuel cartridge 2 has been assembled with the valve assembly 3 and clamp 9 sprung home beneath the cartridge and base 5, the seals are maintained against fuel leakage for the operative life of the fuel in the cartridge. In the event it becomes desirable to remove a cartridge 2 from valve assembly 3 prior to the exhaustion of fuel from can H, this may be done and slit 2! in grommet bud 18 will normally close and seal itself against fluid escape from the can.

For this purpose it is desirable .to employa grommet material that will not set too quickly after opening thereof and that will retain its resilience over a reasonable period of time. Ordinarily, except-under emergency conditions, it is inadvisable to remove a cartridge prior to exhaustion of its fuel, if the assembly has resulted in a setting of the grommet material suflicient to prevent closing of slit 2i upon removal of tube 23 therefrom.

The upper end of tube 28 leads to a recess 34 above plug 30 and from thence to a passage 35 extending upwardly to a transverse passage 35 axially aligned with valve stem 26. A frustoconical shoulder 31 in passage 36 receives a conical pointed inner end 38 of valve stem 26 to effect closure of passage 36, thereby constituting the valve shutoff of fuel for the torch.

'"The valve stem 26 is threaded into the flange 25 and is sealed at its outer end by a packing washer 2'5 abutting the end of flange 25, and a packing nut til threaded upon the flange and compressing the packing 38 against stem '26.

The innerend-portion of stem 28 is of smaller diameter than the threaded outer end portion and carries a throttling valve washer M disposed on the stembetween a retainer ring 52 and a stiff coil spring 43, the latter having its outer end engaging a shoulder 64 on the stem 25.

The washer d! has a skirt 35 extending inwardly and adapted to abut a flat shoulder 25 in the valve body 22 surrounding the valve 2? to provide' a throttling valve 41 which is normally closed byspring 43. j When valve stemZt is threaded outwardly initially to open valve 2?, spring 43 retains valve 4"! closed except for normal tolerance abutment conditions which providesfor about a thousandth of an' inch crevice at various locations around the circumference whereby liquid fuel passing through valve 2? is confined and released at such rate as to gasify as it passes valve t? for initial lighting of the torch.

The gas passes from around valve 47 to a vertical passage 28 in valve body 22 and from thence to the spaceisurrounded by coupling flange 22.

The washer il' should be sealed against stem 26.. by means of a seal washer 49 and retainer washer 5t therefor disposed between throttle washer ti and the inner end of spring 43.

In operation, after the torch is initially lighted the valve stem 26 may be threaded outwardly of valve'body 22 by manual knob 51 on the outer .end of the stem, to open both valves 2"! and 4'! wide. Liquid fuel will then pass upwardly to the burner assembly 5 and will be vaporized into a gaseous fuel before it reaches the burner 52 by heat passing downwardly along the burner tube 53.

The burner assembly d comprises the burner 52 which is shown as a blowtorch burner, a fuel supply riser tube 53 carrying the burner at its upper end, and a coupling nut 53 at the lower end of tube 53 threaded upon upper flange 24 of valve body 22.

A tapered ferrule 55 surrounds riser tube 53 adjacent its lower end and seals against the inside of flange 24 when nut 56 is threaded home upon the flange.

The riser tube 53 is bent at a convenient angle at its upper end for determination of the direction of burner 52 and its flame in use.

A riser insert 56 extends upwardly centrally in tube 53 to reduce the cross section of the opening in the, tube and compel the fuel to pass in contact with the walls ofthe tube to thereby absorb 7 heat and gasify in its passage upwardly to burner 52.

A cotton filter and screen 51 supports insert 56 and is in turn supported in the lower end of riser tube 53 by a retaining ring 58.

The screen and its filter tends to effect a gasification of the liquid fuel at this point when valves 2'! and 4! have been opened and provided there is sufiicient heat input to accomplish the same. In long periods of operation of. the torch the gasification point tends to occur ator close to the filter screen 51.

The burner 52 may comprise various types of torch or burner heads, that shown in Fig. 9 being a usual type of torch construction for blowtorches. In the illustration, Fig. 9, burner 52 comprises a cylindrical body threaded upon. the outer end of riser tube 53 and having an orifice insert 58 at the end of tube 53 to direct a very fine axial stream of fuel into the burner from the u tube.

A burner head 59 is threaded upon the outer end of the body 52 and has the usual baflle, pilot and flame outlet structures which need not be described herein. Primary air is admitted at the discharge point or orifice 58 by means of a plurality of lateral openings 60 extending radially through the burner 52 to the mixing chamber therein.

The burner 52 illustrated in Fig. is of the gas generating type wherein the liquid fuel from riser E3 is forced through small radial holes 6| in the upper end of tube 53' by reason of a plug 62 closing the end of the tube. The fuel passing through holes iii follows the circumferential groove 63 in the outer surface of tube 53. to generating tube ts which passes on the outside of the burner upwardly along the burner body 65 to a shoulder in the head B6 of the burner, thence around. the burner in a groove 61 between the burner head and body 65 and in close metal to metal heat conductive contact therewith, and thence back down the outside of the burner body to a hollow jet head 68 in the base of the burner where the fuel is jetted axially through an orifice into the burner body. The burner body 65 is cylindrical and is conically enlarged at the head or discharge end thereof. Primary air is admitted at the discharge point of the orifice in jet head 68 by means of a plurality of lateral openings 59 extending radially through the burner body 65.

Various ty 385 of burner assemblies 4 may be employed depending upon the service desired, and a torch will be sold with several different types of burners for selection in service and each of which is designed to burn the specified blended fuel efficiently without air adjustment.

The portable torch is adapted for instant lightingby reason of the throttle valve 41 operative upon initial opening of the shutoff valve 21 to pass only a limited amount of gaseous fuel to the burner. After about sixty seconds of burning there is sufficient heat in the burner to permit manual opening of throttle valve. 41 passing liquid fuel to the riser tube 53 where it is gasified upon its way to the burner.

This dual valve operation may be attained by the use of the dual valve of Fig. '7 or the valve illustrated in Fig. 8 wherein the spring 43 acts against the washer l i on the floating valve stem 38'. The movement of valve stem 26' provides dual valve operation first as a shut-off valve and thereafter as a throttle valve when stem 38 is spring-pressed against valve seat 31. However, the illustrated construction of- Fig. 7 has been 8 found the most satisfactory since it provides a Wide lag between initial opening of valve 21 and final opening of throttle valve il. Various valve constructions may be employed to provide the dual valve function described.

ihe mass of the valve body 22 provides sufficient residual heat capacity to effect gasification of the small amount of liquid fuel discharging past valve 41 during initial lighting of the burner.

The liquid fuel employed is one which tends to vaporize as it leaks through small ports of the order of one or two thousandths of an inch in cross section due both to the residual heat present in the metal body of the valve and the drop in pressure on the fuel. Consequently, it is possible to provide an initial lighting gasification by means of throttle valve ii, and to control subsequent gasification by the filter and screen By having the dip tube is extend to the bottom of can ll, the pressure is kept more constant since the gas at the top of can it is retained entrapped to supply the desired pressure upon the liquid fuel. Where the gas in the top of can II is supplied directly to the burner, as where no dip tube i9 is employed, it is necessary to supply more heat to the walls of can I l to effect a boiling of the liquid fuel therein and thereby replenish the gas.

Furthermore, use of the gas at the top of can I l is apt to result in initially utilizing the lighter hydrocarbon content of the blended fuel, making the B. t. 11. output of the burner vary over the life of a cartridge of fuel. In the present construction the blended liquid is forced upwardly of dip tube l9 and to the burner, making a uniform fuel content throughout substantially the entire life of the fuel in a cartridge. The more constant pressure and fuel consistency eliminates the necessity of adjusting the air supply at the torch head during operation.

The torch is normally operated with valves 21 and 41 wide open. Should the gas pressure be lower than desirable, as when the room temperature is below normal, the hand of the operator on the exposed can M will serve to increase the pressure by supplying heat to the can. Should the pressure be higher than desired the operator should remove as much of his hand as possible from direct contact with can i 5.

While the construction is illustrated as blow torch, it will be understood that equivalent application of the invention may be made to stoves and other types of burners. For this purpose wherever the term torch or blowtorch is used herein it is intended to include any equivalent burner where otherwise applicable.

The exact construction employed may vary and the invention may have various embodiments within the scope of the accompanying claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.

I claim:

1. A portable blowtorch or the like, comprising a container of low pressure inflammable blended petroleum hydrocarbon liquid fuel composition having self-pressurizing characteristics at temperatures above about 38 said container being exposed for manual grasping with the hand of the operator to provide an initial pressure therein regardless of the surrounding temperature to feed liquid fuel therefrom, a valve head assembled with said container, a dip tube connecting with the valve head and extending into the liquid fuel of the container to bleed liquid fuel there from and retain within the container the initial gas pressure without substantial diminution by withdrawal of the liquid fuel therefrom, and a torch burner head connected to said valve head and having a fuel passage and port therein adapted to transmit gaseous fuel to a burner flame at rates capable of providing maximum burner operation, said valve head comprising a body having a passage providing communication from said dip tube to said burner head and a valve seat encircling said passage, a valve member movable selectively within said body to positions opening and closing the passage therein and having an abutment fixed thereon to move therewith, said valve member including a relatively movable throttling element carried thereby, and spring means between said throttling element and said valve member to bias said throttling element against said valve seat, said throttling element and valve seat having irregular mating surfaces providing at normal spring pressures thereon a plurality of minute crevices restricting the passage of fuel between the same to allow only the passage of gaseous fuel through the valve head when said valve member is initially released from closed position, said valve member and throttling valve element controlling the passage of said valve head in series relationship, and said abutment being disposed upon movement with said valve member to engage said throttle valve element and effect movement of the latter away from said valve seat to open the passage of said valve head for full burner operation and provide for unrestricted passage of liquid fuel toward said burner port after initial starting of the burner and during normal operation thereof whereby the heat supplied from the burner to the metal surrounding the fuel passage approaching the port effects gasification of the fuel at rates adapted for maximum burner operations.

2. The blowtorch of claim 1 in which the fuel container is a replaceable cartridge having a top closure adapted to be opened by the valve head when assembled therewith, and the dip tube is secured to the top of the container to provide for bleeding of the liquid fuel through the opening effected by the valve head.

3. The blowtorch of claim 1 in which the fuel container is a replaceable cartridge having a top closure comprising at least in part a resilient grommet carrying the dip tube and having a neck confined under pressure with a normally closed axial split therethrough for receiving a fuel bleeding device of the valve head.

4. The blowtorch of claim 1 in which the fuel container is a replaceable cartridge having a top closure comprising at least in part a resilient grommet carrying the dip tube and having a neck confined under pressure with a normally closed axial portion for receiving a fuel bleeding device of the valve head, and said grommet having an upper head for sealing with the valve head, the upper head having a central recess in its top for receiving a tapered shoulder on the bleeding de vice and the outer circumference of the upper head being adapted to be confined in a recess in the valve head.

5. The blowtorch of claim 1 in which the fuel container is a replaceable cartridge having a top closure comprising at least in part a resilient grommet carrying the dip tube and having a neck confined under pressure with a normally closed axial slit therethrough for receiving a fuel bleeding device of the valve head, said grommet being of a heat softening rubber-like material serving as a safety valve for the cartridge whereby pressure and temperatures above normal will effect a discharge of the grommet from the cartridge.

6. The blowtorch of claim 1 in which the fuel container constitutes a replaceable cartridge and the valve head is carried by a shroud for securing the container and valve head in assembled relation, the shroud comprising upper and lower clamping members adapted to receive and confine v the ends of the cartridge, the upper member carrying the valve head and the lower member constituting a base adapted to support the cartridge on end with the torch upright, a strap rigidly secured to one of said members and hingedly secured to the other of said members to determine the space therebetween when the members are disposed in clamping position upon a cartridge,

and a strap hingedly secured to the upper member and having a bent spring end adapted to pass beneath said lower member and to interlock therewith to secure the same clamped against the cartridge.

7. A portable blowtorch and the like comprising a lightweight thin-walled disposable container adapted to be grasped by the hand ofthe operator to provide initial heat thereto, a low pressure inflammable blended petroleum hydrocarbon liquid fuel in said container and having an initial atmospheric pressure vaporization point for the most volatile constituent of the blend substantially below normal room temperature and a final atmospheric pressure vaporization point for the least volatile constituent of the blend substantially above normal room temperature, said fuel blend being substantially free from undue separation by stratification and being capable of developing a gage pressure of the order of twenty-five pounds per square inch at F., said separate fuel constituents requiring different air ratios for efficient burning thereof, a valve head removably assembled with the top of said container, conduit means to conduct liquid fuel to said valve head from near the bottom of the container whereby the blended liquid fuel is delivered to the valve head under the substantially constant pressure of gas above the liquid in the container at normal operating temperatures, valve means in said valve head, a burner having fixed air inlet means to effect efficient burning of the blended gaseous fuel, and means connecting said burner to said valve head and adapted to supply fuel to the burner, said means and said valve head being adapted to supply heat to the liquid fuel as it passes therethrough to gasify the same at the rate of consumption therefore determined by the capacity of said burner and the opening of the valve in said valve head, whereby operation of the burner effects continued progressive gasification of all fractions of the liquid fuel in its approach to the burner and whereby substantially all of the blended liquid fuel in the 'container may be burned efficiently by said burner without adjustment of the air supply thereto.

8. The construction of claim 7 in which the means to conduct fuel to the valve head from near the bottom of the container comprises a clip tube in the container, a puncturable member sealing the upper end of the dip tube, and a bleeder tube carried by the valve head and adapt ed to pierce said member and to enter the upper end of said dip tube to receive fuel therefrom when said valve head is assembled with the container.

9. The construction of claim 7 in which the most volatile major constituent of the fuel is a heat capacity, and a movable valve means there in to control the flow of fuel through said passage, said valve means cooperating with said valve seat and being adjustable to limit the passage of liquid fuel during starting of the burner wherein the residual heat of the valve body vaporizes the small amount of liquid fuel passing the valve means and thereafter being adjustable to provide an open passage for the flow of fuel to the burner during continued operation of the torch and in which the back pressure of the gas in the zone of vaporization confines and restricts the flow of liquid fuel to that necessary for supplying the burner with gaseous fuel.

11. The construction of claim 7 in which the fuel is substantially of the following composition:

Per cent Normal butane 53 Isobutane 2 Isopentane 43 Normal pentane 2 12. The construction of claim 7 in which the means connecting the burner to the valve head comprises a riser tube containing a screen filter, and ariser insert reducing the passage in the tube and increasing heat transfer to the fuel rising in the tube whereby the vaporization of the fuel is assured prior to its reaching the burner.

13. The construction of claim 7 in which said burner comprises a burner body, fuel conduit means in heat conductive relation to said body, means connecting said conduit means to receive fuel from said specified means connecting the burner to the valve head, and orifice means discharging gaseous fuel from said fuel conduit means into said burner body.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 991,725 Kennedy May 9, 1911 1,063,334 Donnelly June 3, 1913 1,721,844 Anderson July 23, 1929 1,895,032 Fisher Jan. 24, 1933 2,167,866 Bennett Aug. 1, 1939 2,305,286 Ward -1 Dec. 15, 1942 2,328,863 Threm Sept. '7, 19 13 2,354,925 Mills et a1 Aug. 1, 1944 2,465,643 Gross Mar. 29, 1919 2x182179 1 Peterson Sept. 27, 1949 2,483,661 Neas Oct. 4, 1949 2,553,486 Thomas May 15, 1951 2,571,435 Flamm Oct. 16, 1951

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