US3002551A - Mixer for air and liquid fuel torch - Google Patents

Description

Oct. 3, 1961 R. H. HUNTER ETAL 3,002,551

MIXER RoR AIR AND LIQUID FUEL TORCH 2 Sheets-Sheet 1 Filed July 9, 1958 #n4-5 4@ Z 67 576 2 [60 6, 245 w' m 4 I J I I 65 I i JNVENTORS Paber'l' HHun-ler Abe J. Hanje mi Oct. 3, 1961 R. H. HUNTER ETAL 3,002,551

, MIXER FOR AIR AND LIQUID FUEL TORCH Filed July 9, 1958 2 Sheets-Sheet 2 INVENTORS Rober HHun'ef Abe J. Hanje W I nite States Patented Get. 3, 1961 Mills, Ohio, and Abe J. Hanje, Northfield, and Harris W. Smith, Bainbridge, Ohio; said Hanje and said Smith assignors to said Hunter Filed July 9, 1958, Ser. No. 747,411 23 Claims. (Cl. 1584-433) -Y This invention relates to a `liquid fuel-burning torch and, in particular, to such `a torch adapted for use'under low and variableV temperature conditions.

Where. it is necessary to use a fuel-burning torch under conditions of extreme cold, as in the military service in starting vehicles, airplanes, tanks, etc., climatic conditions often tends to interfere with the use and functioning of the torch. The effects of extremely low temperatures can be mitigated by mixing primary air with the fuel before projecting it from the nozzle as described and claimed in the copending application for U.S. Patent, .Serial No. 457,803, tiled September 23, 1954, now Patent No. 2,940,- 674, by Robert H. Hunter and Abe I. Hanje for Instant F-lame Torch, and by a generating system in which the fuel is preheated under thermostatic control before it is projected from the burner nozzle as described and claimed in copending application for U.S. Patent, Serial No. 479,- 074, filed December 31, 1954, now Patent No. 2,940,- 515, by Robert H. Hunter, Abe J. Hanje and Harris W. Smith for Thermostatically Controlled Liquid Fuel Burner. There is, however, another factor which figures in the operation of the torch; under the conditions mentioned, the operators-hands are usually protected by gloves which interfere with his ability to manipulate the controls. f v

With this in mind, the present invention consists in and has for its principal object the provision of a generally improved fue1burning` torch of the kindV described in the patent applications referred to; specifically, ya torch in which the controls are so designed, constructed and located that their manipulation is a relatively simple matter even though the hands ofthe operator may be protected by heavy gloves. To this end, the invention provides a fuel-burning torch making use of adjustably disposed metering plugs which, within reasonable limits, may be moved by the actuation of serrated wheels, hereafter referred to as star wheels. Preferably, these wheels are so located that they may, if desired, be moved simultaneously in the same direction by a single forward or rearward motion of one hand.

For the purposes of the present invention, it is not necessary once a suitable mixture adjustment has been accomplished, that the needle Vvalve which controls the ow of the mixture of -air andfuel be freely accessible to the operator as for adjustment on the spur of the moment. main or flow control valve is permanently positioned in the fluid passage that brings the air and fuel together and delivers the mixture to the nozzle. Accordingly, the invention contemplates, among other things, the use of means which serve the purpose of precluding access to the main valve while at the same time acting as an abutment whereby permissible movement of ythe star wheels is conned withinrpredetermined limits,

The invention further contemplates a generally improved generator system, especially a new type of nozzle support of relatively smallmass to minimize withdrawal of heat from the vaporized fuel. Under conditions of extreme cold, the metallic parts of a torch provided with a generating system, particularly if they are of massive construction, withdraw heat from the vaporized fuel to an objectionable degree. `The` loss of heat `in that part .of the system which actually delivers vfuel to the nozzle It is sufficient for practic-al purposes if such r can be serious in the sense that it interferes with the establishment and maintenance of the llame. With this in mind, the invention makes use of an insulated nozzle support of limited mass that tends to heat quickly and, notwithstanding unfavorable environmental conditions, to

retain heat derived from heated fuel on its way to the.

nozzle.

Other objects, advantages Iand features of the invention.y

will be apparent from thedescription which follows and from the accompanying drawings in which:

FIGURE 1 is a side elevation with parts broken away and parts in section of a fuel-burning torch of a kind to which the invention relates. f

FIGURE 2 is a fragmentary top plan of the control mechanism on an enlarged scale, seen as if substantially from line 2 2 of FIGURE l.

FIGURE 3 is a View, partly in section, showing an end elevation of the control mechanism seen as if substan tially from line 3-3 of FIGURE 2.

FIGURE 4 is an expanded view on a still larger scale showing the elements that go to make up one of the star wheel controls and the metering plug with which it is associated.

FIGURE 5 is a bottom plan view somewhat enlarged, of the control mechanism and generating apparatus shown in FIGURE l, the combustion tube shield being indicated in dotted lines.

FIGURE 6 is a section substantially on line 6 6 of FIGURE 3 with certain of the elements, not ordinarily in the vertical axial plane of the device, rotated into such vertical plane in order to show details.

FIGURES 7 and 8 are enlarged sections taken substantially on the lines 7 7 and 8-8, respectively, of FIGURE 6.

FIGURE 9 is a partial section with certain parts in elevation taken axially through the filter carrier appearing in FIGURE l at the bottom or intake end of the fuel supply line.

The fuel tank 1 is characterized by a horizontal crosssection of generally elliptical shape. At the lower end of annular side wall 2 is a concave bottom 3 of conventional construction. At the upper end of the side wall 2 the tank top has a flat horizontal portion 4 extending the full length of the short or minor axis of the ellipse. This top flat portion is flanked by declined plane portions 5, one of which is shown in FIGURE l. On this one of the declined portions 5 is a flat reinforcing annulus 6 within which is mounted a ller tube 7. In the latter is a pump assembly for placing super-atmospheric pressures on the contents of the tank. Rod 8, seen in FIGURE 1, forms part of the pump assembly.

Near one end of the flat top portion 4 is an upright circular flange 9 rigid with the top of the tank. A screw 11 which passes transversely through flange 9 from one side to the other and which extends diametrically across the tank top opening defined by the flange 9 is used to hold in place in such opening a primary or main filter mounting and fuel mixing control block 12 of brass or similar metal. Lower end 13 of the mixing or control block has a cylindrical configuration to permit it to fit snugly within the ilange 9. As shown in FIGURE 3 the cylindrical portion 13 has '-a circumferential groove 14 in which is located an O-ring seal 15. The latter seals against the cylindrically curved inside surface of the flange 9'and prevents the escape of fuel and/or air under pressure between flange 9 Aand circular portion 13.

The mixing or control block 12 is provided with parallel vertical bores 16, 27 indicated in FIGURE 3. At the lower end of the bore 16 is a depending fuel tube 17 which is fast in the block and reaches downward within tank 1 to a point not far above the bottom 3. At its bottom, fuel tube 17 carries a filter assembly 18, shown in detail in FIGURE 9. Filter assembly 18 incorporates a hollow carrier 19 in the closed upper end of which is engaged the threaded lower end of the fuel tube. Immediately below and continuous with the open end of the fuel tube 17 a 'chamber 20 of generally cylindrical shape is formed in the carrier 19. It extends downward to and opens through the bottom of the carrier.

The carrier is tapped as shown in FIGURE 9 to accommodate a hollow plug 21, the upper end 22 of which is threaded forV cooperation with the tapped portion of the carrier intermediate the ends of the chamber 20. The plug 21 has in its side walls a series of openings 23 which permit the entry of fuel into its interior. At its outer end the plug 21 has a base 24 provided with a circular shoulder on which rests a wire mesh strainer 25 that takes the form of a cylindrical sleeve. The assembly as a Whole is so arranged that the cylindrical strainer sleeve is engaged at its ends by the plug bas-e 24 and a circular shoulder adjacent the carrier threads, there being an annular clearance 26 surrounding the strainer and opening through the bottom of the carrier and about the plug 21 to admit the liquid fuel.

At the lower end of bore 27, which admits air to the mixing or control block from the tank, is a filter assembly 28 consisting of a hollow plug similar to plug 21 and a strainer similar to strainer 25. The upper end of the plug is threaded directly into the counterbored and tapped lower end of the air passage 27 in the cylindrical portion 13 of the mixing block 12. A manually operated pressure relief valve 29 of push-button construction permits the user of the torch to vent the tank and restore the pressure within the tank to atmospheric whenever it becomes desirable to do so.

Indicated in dotted lines in FIGURE 2 is a horizontal bore 31 in the block 12. This bore is formed at each of its opposite ends with primary and secondary counterbores in the provision of valve seats for two opposed needle valves 32 and chambers for the latter. Each valve is formed integrally with a cylindrical valve stem 33- that is provided with a peripheral groove in which is located a synthetic rubber O-ring seal 34 which engages the cylindrical wall of the counterbore. Valve stems 33 and seals 34 are accommodated within primary horizontal counterbores 35 of appropriate diameter. At their inner ends, the counterbores 35 communicate with the relatively small diameter bore 31, such communication being permitted or precluded by the needle valves 32. Between the outer ends of the counterbores 35 and the side faces of the mixing block 12 are tapped secondary counterbores adapted to receive threaded portions 36 of the valves.

At their inner ends the two coaxial primary counterbores 35 are at all times in communication, one with the upper end of the fuel bore 16 and the other with the air bore 27.

Tapped axial openings 37 in the outer ends of the threaded portions 36 of the valves are adapted to receive screws 38, see FIGURE 4. With the aid of non-rotational washers 39, screws 38 hold control wheels 42 fast to the metering plugs or valves, wheels 42 being provided to that end with suitable openings 41. The peripheries of wheels 42 are preferably serrated as shown in FIGURES l and 6; it is for this reason that they are referred to as star wheels. Serrated, they are more conveniently operated, individually or together, by a person wearing heavy gloves, who may run the palm of the glove of one hand over the periphery of one or the other or both of them to actuate the valves separately or in unision.

In order that the star wheels 42 may be rotated simultaneously in the same direction, the two metering plugs 36, and therefore the two tapped openingswhich receive them, are threaded oppositely. Thus if the star wheels are rotated counterclockwise as viewed in FIG. l, movement of both is limited by seating of the valves 32 against 4 the valve seats at the opposite ends of the horizontal bore 31.

To limit the movement of star wheels 42 when rotated in the opposite direction, or clockwise, which movement, if continued, would unscrew the metering plugs 36 from the mixing block 12, the star wheels 42 are provided with inwardly directed stops 43. These stops are formed on the ends of drive screws 44: see FIGURE 4. By virtue of these stops, star wheels 42 may be rotated in that direction which tends to unscrew metering plugs 36 only until the stops 43 come into contact with a sheet metal shield 45 mounted on mixing block 12 in the manner shown in FIGURE 6. The shield 45 is of L-shaped vertical cross section and comprises a short forwardly directed horizontal or top portion 46 that bears against the top of the mixing block and a longer downwardly directed vertical portion 47 that bears against the back face of the mixing block. Shield 45 should be wide enough so that its ends project laterally beyond side faces of the block for engagement by the starwheel stops 43: see FIGURES 2 and 3. The shield plate is held in place by a pair of screws 48, of which forward threaded end portions 49 project out the front face of the mixing block 12. The end portions 49 are not threaded into the mixing block 12 but are encompassed by openings 50 so as to be freely rotatable relative to the block in drawing up the combustion tube assembly.

Concealed by the shield 45 is a third metering plug 51 the head of which is received in a stepped bore 52 formed in the mixing block 12 in the manner indicated in FIG- URE 6 and intersecting the transverse bore 31. The metering plug 51 is provided with a peripheral groove and an 0-ring seal 53 and, forwardly of the latter, with a threaded portion 54 of reduced diameter which is received in a correspondingly tapped reduced portion of the bore 52. In open communication with the two branches of the transverse bore 31 is a central mixing chamber 55 into which projects a needle valve 56 on the forward end of the plug 51. By coaction with a seat surrounding the opening through which a coaxial exit bore or passage 57 communicates with the mixing chamber, the needle valve is adapted to regulate the flow of fuel. The bore 57 widens as shown at 58, FIGURE 6, and provides an outlet passage through which fuel or a mixture of fuel and air is discharged from the block 12. The metering plug 51 is permanently adjusted in the mixing block 12 in a position leaving an orifice of the desired size forwardly of needle valve 56. To discourage tampering, it is desirable that the metering plug not be -too easily accessible for adjustment; accordingly, the shield 45 is used as shown to cover the outer or rear end of the plug.

The screws 48 hold in place on mixing block 12 a combustion tube 60 provided with secondary air openings 61. A shroud or flame shield 62, seen in cross section in FIGURE l, is fastened to and about the combustion tube 60. Within the shield 62 and at the outlet end of the combustion tube is a tubular coil 63 to the ends of which are connected conduits 64 and 65. Together with coil 63 and related parts, conduits `64 and 65 comprise a generating system of the type shown and described in the above mentioned patent application, Serial Number 479,074, of Robert H. Hunter, Abe J. Hanje and Harris W. Smith. The fuel that is to be preheated in coil 63 reaches the coil by way of conduit 64 and leaves it by way of conduit 65, all as indicated by arrows in FIGURES l and 5. At its inner end, the combustion tube 60 is cut away as at 66 to accommodate the end of conduit 64: see FIGURE 5.

The conduit 64 is connected to and supported by a mounting block 67 of circular shape rwhich fits snugly within the rear orinner end of the combustion tube 60. The end of the conduit is received in a peripheral recess or opening 68 in the base 67: see FIGURE 7. Communicating with this recess or opening is a radial bore 69 in communication with an axial bore 70, best seen in FIGURE 6.1At the rear end of the bore 70 which opens through the rear face 73 of theblock 67 is a circular recess or counterbore in which is received an O-ring 71 of rubber that bears and seals against the mixing block 12. The latter has a planar coupling face 72 cooperating with the planar coupling face 73 of the mounting base 67; the coupling faces 72 land 73 appearin FIG- URE 6. 1

The circular mounting base 67 is held fastto .the mixing block 12 by means of the screws48. The threaded portions 49 of such screws areengaged in correspondingly tapped openings in the mounting base. The burner tube 60 is fastened to the mounting base 67 by drive screws 74, seen in FIGURES Sand 7. Inasmuch as the mounting base 67 is rigidly attached to the mounting block 12, the burner tube 60 likewise is held rigidly in place on the mounting block.

Forwardly of the mounting base 67 is a circular washer 75 of heat-insulating material such as asbestos vthat is adapted to stand up well at high temperatures. It is clamped in place between the mounting base 67 and an elongated secondary filter mounting block or nozzle base 76 of generally square or rectangular cross section. The filter block or nozzle base 76 is disposed transverse to the axis of the combustion tube with one of its flat sides against the vinsulating washer. It projects out of the combustion tube 60 through an opening 77, best seen in FIGURE 5, in the side wall of the tube. The filter block or nozzle base is held in position on the mounting base 67 by means of screws' 78 which are disposed in staggered relation to the screws 48: see FIGURE 7. These screws 48 are threaded into tapped openings in the mounting base 67, passing freely through suitably located aligned openings in the washer 75.

On the forward face of the lter block or nozzle base '76 is mounted a nozzle 80 which incorporates' althread'ed portion 81 that extends rearwardly and is screwed .into a threaded socket in the base member 76 as shown in FIG. 6. The aperture in the nozzle 80 communicates with .a chamber 82 to the rear of the threaded portion 81 and, through it, with a bore 83 that extends radially With respect to the combustion tube axis, through the nozzle base. It in turn is in communication with an elongated chamber 84 in that portion of nozzle base 76 which extends radially through the opening 77 and beyond the surface generated by the side wall of the combustion tube 60. A short forwardly extending bore 85 that runs laterally from the chamber 84 communicates with a shallow recess 86 into which the conduit 65 is brazed in place.

Located in chamber 84 between the longitudinally extending bore 83 and the outer end of the lter block or nozzle base 76 is a filter assembly 87. It includes a threaded plug 88 engaged in a tapped portion of the wall of the chamber 84. A washer 89 intervenes and seals between the outer end of the nozzle base 76 and the plug 88. A cylindrical strainer 90, formed of wire mesh, completes the filter assembly 87. The inner end of the strainer bears against a shoulder 91 near the inner end of the chamber 84, being held in place by the plug 88 and surrounded by an annular clearance space.

The filter block or nozzle base 76 is formed in the manner described for the express purpose of minimizing the mass of heat conducting metal to which heat can be lost from the mixture of fuel and air on its way from'the conduit 65 to the combustion tube 60. 'Ihis mixtureis one that has been preheated before entering the nozzle base 76. It first passes through the strainer 90 and then through the chamber 84, the longitudinal bore 83, and the chamber -82, finally entering the bossl portion 81 of the nozzle 80.- `It emerges through the aperture in the forward face of thev nozzle 80 as a fine spray, burning in the combustion tube 60 with the aid of secondary air inspired through the openings 61.

Another feature of novelty characterizing the invention resides in the use ofthe filter assembly 87 inthe filter block or nozzle base '76, where it screens out solid materials such as particles of carbon that are formed by thermal decomposition of the fuel in the coil 63. With filter assemblies 18 and 28 respectively screening out foreign particles from the fuel and air before they are brought together in mixing chamber 55, solids derived from the decomposition of the fuel represent the only other source of contaminants of nature such as to interfere with the flame. By using three filter assemblies in the manner described, it is relatively easy to maintain the flame without interruptions attributable to the presence of contaminants.

Thus the invention provides a fuel-burning torch which requires a minimum of attention from the user `other than occasional cleaning of the strainers in the filter assemblies. The metering plugs 36, coupled as they are to the star wheels 42, are readily movable in unison into and out of the positions in which the needle valves 32 permit or preclude the flow offluid into the mixing chamber. The precise positions of the needle valves can easily be determined by the positions of the single turn star wheels 42 which are so arranged as' to lend themselves to simultaneous operation ywith one hand, leaving the users other hand free `for other tasks.

It is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention. v

We claim:

1. In a liquid fuel torch, a tank for containing liquid fuel under pressure, a burner tube having an inner fuel receiving end and an outer flame discharging end, a mounting base at and within the inner end of the burner tube; a coupling face on one side of the mounting base; a nozzle base in the burner tube on the side of the mounting base opposite the coupling face, heat insulating means between the mounting and nozzle bases, a nozzle on the nozzle base; and means defining a passage system for conducting fuel under pressure from the tank to the nozzle, such passage system including communicating with one another, fluid flow passages in the mounting base, nozzle base and nozzle.

2. A torch as in claim l in which the nozzle base is secured to and solely suppor by the mounting base.

3. A torch as in claim l in which the burner tube is formed with a lateral opening and the nozzle base projects through said opening in the 4burner tube beyond the lateral limits of the burner tube.

4. A torch as in claim 3 in which a filter is mounted in the projecting portion of the nozzle base for facile removal and replacement, said filter being in communication With the fluid flow passage in the nozzle base.

5. A torch as in claim 4 in which the projecting portion of the nozzle base is formed with an opening and the filter is removable through such opening in the base, and a removable plug closing such base opening.

6. In combination with a torch, a tank adapted to receive and contain under pressure a body of fluid fuel, said tank having an opening, mounting means on the tank and defining a socket continuous with the tank opening, said socket having a cylindrical internal Wall, a fuel flow control block having a base portion receivable within the socket in assembling the block to the mounting means, the base portion having a cylindrical external wall complemental to and fitting snugly within the socket wall, one of said walls being formed with a circumferential groove, a resilient ring disposed in such groove and sealingly engaging the other of the cylindrical walls to prevent escape of pressurized fluid from the tank between the walls, the block being formed with a fuel chamber and with passage means extending through the base portion communicating the chamber with the interior of the tank, and fastening means extending diametrically through the mounting means and the base portion holding the block fixedly in place relative to the mounting means, said fastening means being located outwardly of the resilient ring and spaced laterally from the communicating passage means.

7. A torch combination as claimed in claim 6 in which the base portion of the control block is formed with au end face directed toward the interior of the tank, the communicating passage opens through said face and includes a threaded portion, an inlet fitting mating with the threaded portion of the passage for facile removal and replacement, and strainer means carried by the fitting and held captive between such fitting and said base portion of the block.

8. A torch combination as claimed in claim 7 in which the inlet fitting is formed with a shoulder, the strainer comprises a cylindrical sleeve, and the strainer is engaged at one end against the end face of the block and at the other end against the shoulder of the inlet fitting.

9. A torch combination as claimed in claim 6 in which the mounting means is formed with a shoulder surrounding the socket and the control block is formed with abutment means engaged against the shoulder locating the base portion in predetermined axial position relative to the mounting means.

l0. A torch combination as claimed in claim 6 in which the socket includes coaxial inner and outer portions of different cross sectional areas, the cylindrical wall defining the inner portion, and the outer portion being located outwardly of the resilient ring from the tank and larger than the inner portion, thereby constituting an entry facilitating assembly of the base portion of the block into the socket.

1l. A torch combination as claimed in claim 6 in which the communicating passage means includes separate fuel and air passages located on opposite sides of the fastening means.

112. In a liquid fuel torch of the type comprising a tank for containing the fuel, a nozzle through which the fuel is projected to burn in suspension, a combustion tube, means mounting the nozzle to project fuel into one end of the tube, and means defining a passage system for conducting fuel under pressure from the interior of the tank to the nozzle; said mounting means comprising in combination a filter block defining intersecting passages, said block being formed with a chamber at the passage intersection, said passage system comprising the chamber and intersecting passages, said block projecting laterally through the combustion tube, having one portion located inside such tube and another portion located outside such tube, the nozzle being mounted to the inside portion and the outside portion of said block being formed with a threaded passageway opening into said chamber, a closure plug screwed into the passageway and adapted for facile removal and replacement, and a screen disposed in the chamber for straining fuel fiowing therethrough, the screen being confined between the plug and the block and removable from the chamber through the opening upon removal of the plug.

13. In a torch as defined in claim 12 the mounting means including a control block fast to the tank and the passage system comprising passages in the control block communicating with the interior of the tank and with one of the intersecting passages, the nozzle, tube and filter block being mounted together as a burner unit for facile removal and replacement from and on the control block and the nozzle being disposed to project fuel along a path having its axis substantially normal to the axis of one of the intersecting passages.

14. In a torch as defined in claim l2 the mounting means including a control block fast to the tank and the passage system comprising passages in the control block communicating with the interior of the tank and with one of the intersecting passages, said fuel system including means adapted to heat fuel being conducted to the nozzle, and means within the combustion tube supporting the filter block on the control block in heat insulated relation to minimize cooling of the heated fuel in such filter block. I

y15. In -a torch as defined in claim l2 the mounting meansl including a control block fast to the tank and the passage system comprising passages in the control block communicating with the interior of the tank and with one of the intersecting passages, means securing the other end of the combustion tube to the control block, means securing the filter block to the combustion tube, the combustion tube having a lateral opening adjacent its other end, the filter block projecting through such lateral opening, and the filter block opening being outside the combustion tube.

16. In a liquid fuel torch of the type comprising a tank for containing the fuel, a nozzle through which the fuel is projected to burn in suspension, a combustion tube, means mounting the nozzle to project fuel into one end of the tube, and means defining a passage system for conducting fuel under pressure from the interior of the tank to the nozzle; said mounting means comprising a control block and a nozzle block, means securing the nozzle block to the control block in heat insulated relation, means securing the other end of the combustion tube to the control block, the combustion tube having a lateral opening adjacent such other end, the nozzle block having an end projecting through the lateral opening in the combustion tube, the nozzle being secured to the nozzle block, the passage system including a conduit connected at one end to receive pressurized fuel from the tank and at its other end being connected to the projecting end of the nozzle block, and the nozzle block being formed with a passage extending between said other end of the conduit and the nozzle.

17. In a liquid fuel torch of the type comprising a tank for containing the fuel, a nozzle through which the fuel is projected to burn in suspension, a combustion tube, means mounting the nozzle to project fuel into one end of the tube, and means'defining a passage system for conducting fuel und'er pressure from the interior of the tank to the nozzle; said mounting means comprising a control block, a base member fast to the control block and a nozzle b1ock,means securing the nozzle block to the base member in heat insulated relation, the other end of the combustion tube being received over both the nozzle block and the base member and secured to the latter, the combustion tube having a lateral opening adjacent such other end, the nozzle block having an end projecting through the lateral opening in the combustion tube, the nozzle being secured to the nozzle block, the passage system including a conduit connected at one end to receive pressurized fuel from the tank and at its other end being connected to the projecting end of the nozzle block, and the nozzle block being formed with a passage extending between said other end of the conduit and the nozzle.

18. In a torch of the type comprising a tank for containing liquid fuel and air under pressure, a nozzle through which a mixture of fuel and air is projected to burn in suspension, and means defining a passage system for conducting fuel and air under pressure from the interior of the tank to the nozzle; said passage system including a control block formed with separate fuel and air passages -and mounted rigidly on top of the tank, means communicating the fuel passage with the bottom and the air passage with the top, respectively, of the tank interior, valve means actuatable to control the flow of fuel through the fuel passage, valve means actuatable to control the flow of air through the air passage, the control block being formed with common passage means for receiving fuel and air from the fuel and air valve means and conducting such fuel and air to the nozzle, fuel and air control wheels, means mounting the fuel Wheel on one and the air wheel on the other side of the control lblock for rotation in parallel planes, the fuel control wheel being operatively connected to the fuel valve, the air control wheel being operatively connected to the ait valve, and the wheel peripheries projecting in said planes both horizontally beyond and vertically above the control block and being adapted for simultaneous engagement by one hand of an operator for simultaneous single hand adjustment of the fuel and air flow through the control block to increase the ow rate of both fuel and air upon rotation of the wheels in one direction and to decrease both flow rates upon rotation thereof in a reverse direction.

19. A filter assembly for the inlet of a liquid fuel torch comprising a hollow carrier open at one end, said carrier being formed with a cylindrically walled chamber continuous with said end opening and with an internally threaded portion remote from such opening, a hollow plug extending axially through the chamber and having a threaded end screwed into the threaded portion of the carrier, the plug having a body portion separated from the chamber wall by an annular clearance space, a tubular screen embracing and carried by the plug, stop means on the carrier and the plug engaging the screen and locating the latter in predetermined axial relation to the plug, and the plug being formed with openings communicating the interior of the plug with the clearance space.

20. In a liquid fuel torch of the type comprising a tank for containing liquid fuel, a control block and a burner tube; a mounting base Within and at the inner end of the burner tube; coupling faces on the control block and on the mounting base, said coupling faces mating with each other; a nozzle base in the burner tube on the side of the mounting base opposite the coupling face of the latter; a nozzle on the nozzle base; and means delining a passage system adapted to conduct fuel under pressure from the tank to the nozzle, such passage system including fluid passage means in the control block, mounting base, nozzle base, and nozzle, and conduit means located exteriorly of the burner tube connecting the passage means in the mounting base to the passage means in the nozzle base.

21. In a torch of the type comprising a tank for containing liquid fuel and air under pressure, a nozzle through which a mixture of fuel and air is projected toburn in suspension, and means defining a passage system for conducting fuel and yair under pressure from the interior of the tank to the nozzle; said passage system including a control block formed with separate fuel and air passages, means mounting the block rigidly on top of the tank, means communicating the fuel passage with the bottom and the air passage With the top, respectively, of the tank interior, valve means actuatable to control the flow of fuel through the fuel passage, valve means actuatable to control the flow of air through the air passage, the control block being formed with common passage means for receiving fuel and air from the fuel and air valve means and conducting such fuel and air to the nozzle, fuel and air control wheels, means mounting the fuel wheel on one and the air wheel on the other side of the control block for rotation in parallel planes, the fuel control wheel being operatively connected to the fuel valve, the air control wheel being operatively connected to the -air valve, the control block being formed with a bore communicating with the common passage means, a valve element mounted in said bore, the bore having an opening through which the valve element is removable and insertable, a plate, means securing the plate to the control block over and as a closure for the bore opening, the plate having portions projecting laterally beyond the sides of the block, the

wheels having stop means engageable with the projecting portions of the plate to limit rotative movements of the Wheels, and the plate being readily movable from the block for access to the bore opening and for disengagement of the stop means to permit rotative movements of the Wheels beyond said limit.

22. In a torch of the type comprising a tank for containing liquid fuel and air under pressure, a nozzle through which a mixture of fuel and air is projected to burn in suspension, and means defining a passage system for conducting fuel and air under pressure from the interior of the tank to the nozzle; said passage system including a control block formed with separate fuel and air passages, means mounting the block rigidly on top of the tank, means communicating the fuel passage with the bottom and the yair passage with the top, respectively, of the tank interior, valve means actuatable to control the ow of fuel through the fuel passage, valve means actuatable to control the flow of air through the air passage, the control block being formed with common passage means for receiving fuel and air from the fuel and air valve means and conducting such fuel and air to the nozzle, fuel and air control wheels, means mounting the fuel wheel on one and the air wheel on the other side of the control block for rotation in parallel planes, the fuel control wheel being operatively connected to the fuel valve, the air control wheel being operatively connected to the air valve, a mounting base on one side of the block, the nozzle being secured to rand supported by such base, a plate on the other side of the block, screw means extending through the plate and the block and having connection with the mounting base to hold the baseand the plate in predetermined relation to the block, the plate having portions projecting laterally beyond the block, the wheels having stop means engageable with the projecting portions of the plate to limit rotative movements of the wheels, and the screw means being readily removable for removal of the plate from the block for disengagement of the stop means to permit rotative movements of the wheels beyond said limit.

23. In a torch as defined in claim 18 the wheels having deeply serrated peripheries to facilitate actuation by the gloved hand of an operator, said Wheel peripheries lying in circles each having a diameter substantially equal to the axial spacing of the Wheels.

References Cited in the file of this patent UNITED STATES PATENTS 1,364,972 Andersone et al Ian. 11, 1921 1,456,718 Anderson May 29, 1923 1,498,808 Pagel June 24, 1924 1,507,927 Miller Sept. 9, 1924 1,705,368 Knavitz Mar. 12, 1929 2,463,124 Sims Mar. 1, 1949 2,605,821 Lindahl Aug. 5, 1952 2,772,898 Seedler Dec. 4, 1956 2,809,101 Mitchell Oct. 8, 1957 FOREIGN PATENTS v82,610 Sweden Feb. 19, 1935 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,002,551 October 3,. 1961I Robert H. Hunter et al.

It is hereby certified that error appears in the above numbered paf; ent requiring correction and that the said Letters Patent should read ae corrected below.

Column 6, line 44, for

I movable" read removable Signed and sealed this 20th dayi of August 1963.

(SEAL) Attest:

ERNEST W. SWIDER Commissioner of Patents

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