US2344428A - Burner for fluid fuel - Google Patents

Description

March 14, 1944-.y v E TORREY 2,344,428

BURNER FOR FLUID FUEL Filed Sept. 30, 1940 2 Sheets-Sheet 1 i w vmq [NI/ENTOR Enh/ARD L. ToR/PEY A TT ORNE Y March 14, 1944.

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E. L. TORREY BURNER FOR FLUID FUEL I D /N VENTO/e E. L. TORRE-Y 9M? ATTORNEY Patented Mar. 14, 1944 UNITED STATES PATENT OFFICE BURNER FOR FLUID FUEL Edward L. Torrey, Oakland, Calif.

Application September 30, 1940, Serial No. 358,951

12 Claims.

The invention relates to a uid-fuel burner particularly designed for use in the heating of air and other fluids.

An object of the invention is to provide for an emcient production of heat from the combustion of the so-called low-grade fuel oils, and particularly mineral oils.

Another object is to provide a burner in which the complete gasification of all combustible fractions of a fuel oil is assured.

A further object is to provide a combined generator and burner having means operable to prevent the accumulation of free carbon thereupon.

Yet another object is to provide a fully and uniformly oxygenated gaseous mixture for feeding the re of the burner.

A still further object is to provide a burner which is operable in whole or in part with fuel gases generated externally thereto.

The inventionpossesses other objects and features of advantage, some of which, with the foregoing, will be set forth or be apparent in the following description of a typical embodiment thereof, and in the accompanying drawings, in which,

Figure 1 is a perspective view showing the burner of my invention in use as part of an airheating unit, portions of the structure being broken away.

Figures 2 and 3 are sections of the burner taken respectively at the lines 2-2 and 3-3 in Figure 5.

Figure 4 is a fragmentary perspective view of a scraper element of the burner.

Figure 5 is an enlarged vertical axial section through the burner assembly.

Figure 6 vis a side view of the fuel-vaporizing portion of the burner.

Figure 7 is a fragmentary View at the line I-'I in Figure 6.

Figure 8 is a horizontal plan View at the line 8 3 in Figure 6.

As particularly illustrated, a burner unit ernbodying the present features of the invention is disclosed as being operatively installed in an airheating furnace I2 which essentially comprises a casing I3 providing an air-heating space I4 surrounding a combustion chamber I5 comprising a member i5 having end walls I1 and a continuous side wall I8, and supported on legs 23 extending from its bottom. The burner II extends through and from the end Walls I1 in sealed relation thereto and is supported thereby. A flue pipe I9 Aextends from an upper point of `the casing I6 vissued on Nov.` 20, 1934, and provides a particularly efficient heat exchange from its interior and through its Walls to air in the space I4, through which space air is arranged to be circulated by convection in a usual and Well-known manner, the heated air escaping at one or more openings 2l provided at the top of the furnace casing. The air to be heated is admitted at a lower point of the casing i3, which casing may be provided with suitable baliles (not shown) for directing the incoming air against the combustion chamber walls I'l and I8 for its heating.

The burner unit II includes a tubular shell 22 which has its ends extended through flanged openings 23 at opposite ends of vthe furnace casing, the axis of the shell being horizontal. By particular reference to Figures 1 to 3, it will be seen that the shell 22 has a general air foil cross-section with its trailing edge uppermost in conformity with the disposal of the casing I6. At its lower side, the shell 22 is provided with an opening which extends longitudinally of the shell between points which lie inwardly of its points of sealed engagement with the ends I1 of the combustion chamber casing I5; the side edges or lips 24 of said shell opening lie in a horizontal plane below the widest part of the shell. It will be noted that the shell bore preferably tapers somewhat from its center in both horizontal and vertical section to compensate for the heating of the air which enters from both ends of the air tunnel provided by the shell 22. Also, the walls of the shell 22 are thickest centrally of the length of the shell.

An elongated pan member 26 depends from the shell 22 with its cavity below and opposite the bottom shell opening dei-ined by the lips 26, and has its ends notched to closely receive the tubular shell ends 25. Ears 21 extend horizontally from the shell 22, and the pan 26 is bolted to and beneath said ears; as shown, the pan 26 is formed with mutually coplanar side flanges 28 receiving bolts 29 which secure the pan to the shell, The pan 29 is arranged to function as a drip pan and priming cup with respect to the burner assembly, and the plane of its rim dened at the flanges 23 is disposed above the plane of the shell opening and is laterally spaced from the opposed shell walls. To facilitate combustion in the Vpan 26, the sides and bottom thereof may be lined with Ya metallic mesh overlaid with asbestos as isI indicated. Y

The gas-generating elements of the burner are supported by and between the tubular end portions 25 of the shell 22 and essentially. comprise an assembly of elongated pans aligned in a common vertical plane and from which unevaporated liquid fuel may descend gravitally until evaporated to provide gases for burning, it being recalled thatrnineral fuel .oils are made up of vfractions which evaporate at different temperatures. Essentially, the elements of the gasgenerating assembly comprise upper and lower members 3| and 32 respectively which cooperatively dene a cavity 33 in which a plurality of bubble trays are mounted; two trays 34 and 35 are shown. The members 3| and 32 comprise intermediate trough-like portions providing the upper and lower parts of the cavity 33, said portions extending inwardly and between the ends of the pan 25 and having stem extensions 36 and 31 respectively.

The stems 31 of the member 32 rest upon adjustment screws 38 which extend from the bottom of the sleeve ends 25 for use in levelling and vertically adjusting the tray assembly within the combustion chamber l5. The member 3| is xedly mounted upon spacing blocks 39 provided at the ends of the stems 31 of the member 32, and is fixed in place by means of tension bolts 4i) operative at and between the inner ends of the stems. Preferably, and as shown, the portions of the bolts 4|! nearest their heads are slidably engaged in longitudinal slots of corresponding stems and are threadedly engaged in the other stem. The spacing blocks 39 are preferably formed of a slightly compressible material such as asbestos, and are compressedly held in place between the stem extremities by the tightening of the bolts. The arrangement is designed to provide for relative longitudinal expansions of the members 3| and 32 without buckling or strain, such expansions arising from the high and possibly different temperatures to which they are subject during the functioning of the burner.

It will be particularly noted that the bottom and top edges of the members 3| and 32 respectively are spaced to cooperatively define slits 42 substantially in the plane of the bottom opening defined by the lips 24 of the shell 22, and through which gas escapes from the cavity 33 for its r combustion along the outer face of the shell. The members 3| and 32 are notched upwardly and downwardly from the plane of the slits 42 and solely at the ends of the cavity 33 to provide air inlets 4|; said notches 4| of the member 32 also function to limit the liquid capacity of the basin provided by the member.

The bubble trays 34 and 35 are similar, and are mounted in horizontal position within the members 3| and 32 respectively. The extremities of the tray 34 are secured to downwardly facing seats at the ends of the cavity of the member 3| by screw bolts 43, and bolts 43 also secure the extremities of the tray 35 to upwardly facing seats provided at the ends of the cavity of the member 32, said trays being spaced from the plane of the slits 42 at opposite sides thereof, A line of liquid overflow outlets 44 is provided in and along the tray bottoms and in bosses 45 which extend from the tray bottoms to planes slightly below those of the tray rims. The outlets 44 of the trays 34 and 35 are in mutually staggered relation whereby liquid overflowing from the tray 34 through an outlet 44 may not fall directly into an outlet of the underlying tray 35. The bottom of the member 32 receives and retains the overflow from the tray 35 up to a level determined by the bottoms of the vend notches 4| of the member.

Means are provided in the member 3| for admitting both fluid fuel and air to the cavity 33. Centrally thereof, and at its top, a fuel pipe 46 is connected to the member 3| for the drip discharge of liquid fuel upon the upper tray 34, said pipe extending through the shell 22 from one end thereof. The liquid fuel is delivered to the pipe by gravity from a suitable drip valve 41 of a supply pipe 48 and through an elbow 49 having a plate 50 at its end perforated around the valve nozzle which engages it. The pipe 46 is provided with a dam 5| within it and at its lower end whereby it may retain a small amount of liquid fuel to the dam level for overflow into an elbow 52 as the liquid is supplied through the valve 41; the present dam 5| is provided as an annular constriction at the discharge end of the pipe bore, and the constant retention of some liquid fuel in the pipe behind the dam provides for a preheating thereof before the fuel falls into the upper tray 34.

A circle of holes 53 is provided axially through the boss portion 54 of the member 3| which receives the down-turned discharge end of the elbow 52, and upright slots 55 extend longitudinally through the member 3| from the boss 54 to both ends of the cavity 33; the holes 53 and slots 55 provide passages for the ow of air from the shell 22 into the cavity 33. As will hereinafter be brought out, the operation of the present burner creates a suction in the pipe 45, and such suction is relieved in part by the induction of air through the air inlet openings at the top of the elbow 43, through the holes 53, through the slots 55, and through the notches 4| in the ends of the members 3| and 32 which cooperatively provide the gas-generating space 33.

Recalling that the underlying pan 25 is open along opposite sides of the shell 22, it will now be noted that a preliminary combustion of liquid fuel in said pan is arranged to heat up the described gas generating elements for the generation of gaseous fuel from the liquid therein. Accordingly, an initial charge of priming fuel is arranged to be placed in said pan through a pipe 53 entering one end or by an overflow of liquid fuel from the member 32. As indicated in yFigure 5, the pipe 56 extends through the front of the furnace casing I3 and the member i6 to its connection in the pan end, and its outer end is provided with an upturned funnel 51 from which it slopes slightly to its discharge end within the pan. The top of the funnel 51 is below the level of the pan rim whereby an overflow return of liquid is permitted for limiting the amount of the priming charge, priming liquid being supplied to the funnel 51 from a valved drip pipe 58. A constant flow of liquid fuel through the pipe 5E may be provided to supply a constantly lit pilot flame within the pan and at the inner end of the pipe 5B which may be provided with a jet nozzle.

When the priming liquid in the pan 2B is burning, the gas-generating elements are heated for the generation of gasied fuel and its discharge through the slits 42 for its combustion, it being noted that the combustion of the priming charge and generated gases induces a convection flow of air into and through the cavity 33 and from the slits with the gasied fuel whereby a zone of combustion is provided against the outside of the shell. In this manner, the combustion is arranged to take place upwardly along the sides of the shell 22, the supply of gaseous fuel being automatically generated and maintained after the priming charge has been consumed.

The present burner assembly is adapted for the efficient burning of gaseous fuel which has been generated outside of the burner, such gaseous fuel being supplied to and through the burner supply pipe 46. While pre-generated gaseous fuel Amight 4be supplied through ythe pipe 48, it is `preferred to independently supply any gaseous fuel at the elbow 49. Preferably, and as shown, a gas pipe' 59 is connected to the elbow 49 and terminates in a nozzzle El which is directed axially of the pipe 48 for discharging thereinto; in this manner, liquidand gaseous fuels may be introduced together into the burner in any desired proportion. It will be understood that the pres-l ent burner may be operated entirely with a pregenerated gas, in which case only the evaporation operation at the trays 34 and 35 is omitted in the operation of the burner which also acts as a gasair mixer; the arrangement is understood to provide for utilizing liquid and/or gaseous fuels as they are available and without requiring any changes or adjustments of the burner parts for any change-over.

Means are provided for preventing an undesirable accumulation of carbon or scales on the surfaces of the members 3| and 32 at and adjacent the slits 42. As shown, a rod 63 is reciprocably engaged between the members 3| and 32 in the plane of the tray outlets 44, and carries scraper assemblies 64 providing scraper blades for operation along certain surfaces of the members. The assemblies 64 are mounted at equally spaced points along the rod 63 and generally within the cavity 33, and the permitted Working strokes for said assemblies at least equals their .mutual spacing whereby to permit a complete scraping of the surfaces to be operated on. One end of the rod G3 extends from the burner assembly, and means are provided for effecting an operative reciprocation and control of the rod; as particularly illustrated, a knob 65 is fixed on the extending rod end for use in manually reciprocating the rod, it being understood that an intermittently operative mechanical means might be provided for the purpose.

Referring particularly to Figures 2 to 5 inclusive, it will be noted that the scraper assemblies 6d include arms 66 extending radially from hubs Eil Vfixed on the rod B3, and freely through the slits d2. Blades 68 extend upwardly from the arms 66 for engagement with and along the adjacent inner wall faces of the member 3|, and similar blades 69 depend from the arm for engaging with and along inner face portions of the member 32. Blades 'H depend from the outer ends of the arms 66 for operative engagement with and along the outer side faces of the member 32 below the slits 42, and it Will be understood that each arm portion between the inner and outer blades thereon'is arranged to function as a scraper blade in the slits. The various blades 68 and 63 and 1| may lightly and resiliently engage the surfaces which they are to clean, and the rod 63 is loosely engaged in and between the stem portions S and 31 of the members 3| and 32 I respectively whereby the necessary freedom is provided for lateral and rotary and axial movements of the scraper assembly. In this manner, full operative applications of the scraper unit may be effected by actuations of the rod 53 while vthe burner is in operation.

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the rod 63 is understood to be independent of its use as a mounting for the scraper assemblies 64. Since the vaporization of the liquid fuel is facilitated by increasing the exposure of its surfaces to heat, the splashing of the liquid fuel upon all surfaces of and within the cavity 33 is essential to a maximum efficiency of vaporization. Also, it will be understood that the number and arrangement of bubble trays within the cavity may be Varied to the same end, and that no limitation is to be implied as to the particularly disclosed arrangement.

Means are provided for insuring a thorough mixing of the gaseous discharge from the slits 42 with air received directly from the shell 22 and before the mixture reaches the combustion zone along the outside of the shell, it being noted that the intake of air through the openings 53 and 55 provided therefor at the top of the generator member 3l does not provide all of the oxygen needed to support the combustion of the gaseous fuel. As particularly shown, rod-like members l2 are mounted in the general plane of the slits 42 in the shell space between the assembly 3|32 and the bottom rims of the shell, the baffle rods 'l2 being shown as carried on suitable brackets I3 mounted on the member 3|.

In burning gaseous fuel emitted from the slits 42, a particular disposal of the slits with respect to the common plane of the shell lips 24 will be necessary for the best operation of the burner With a particular fuel, and the screws 33 which support the generator assembly are utilized for providing any adjustment which may be needed, this being accomplished without dismantling the generator and while the burner is in use. At normal burning conditions, the base of the fire is outwardly of and along the shell lips 24, yet the re base may extend to the outer sides of the slits 42 under low-fire conditions; in either event, the flow stream of the gaseous fuel mixture and combustion products is between said lips and creates a desirable turbulent flow of air through the shell bore to complete the necessary combustion-supporting air supply to the lire.

From the foregoing description taken in connection with the accompanying drawings, the advantages of the construction and operation of the present burner will be readily understood by those skilled in the art to which this invention .appertains While I have described the features and principles of operation of an assembly which I now consider to comprise a preferred embodiment of my invention, I desire to have it understood that the showing is primarily illustrative, and that such changes may be made, when desired, as fall within the scope of the following claims.

I claim:

l. A fluid fuel burner comprising a member arranged for its heating and providing an elongated cavity therein having its longitudinal axis horizontal and having air and fuel inlets and a side outlet for the discharge of the gaseous mixture resulting from the mixing vof the inlet air and fuel, said outlet comprising an horizontal slit, and an open-ended tubular shell enclosing said member longitudinally of said slit in spaced relation from the member and provided with a bottom opening having its upper edge disposed substantially in the same horizontal plane with the slit and arranged for the passage of the said gaseous mixture beneath said edge for its combustion along the outer shell surface.

2. A structure in accordance with claim 1 having means adjustable to vertically adjust the position of the member in the shell.

3. A structure in accordance with claim 1 whereof the shell is of air-foil form with its trailing edge extending upwardly.

4. In a liquid fuel burner, a down-draft vaporizer comprising a hollow member arranged for its heating by the combustion of vaporized fuel discharged therefrom and providing a horizontally elongated cavity therein having Aan air inlet slot along its top and a vapor outlet slot along its side and a fuel inlet, a scraper blade engaged in said vapor outlet slot, and a. means for actuating said scraper to clean the slot during the operation of the burner.

5. In a liquid fuel burner, a down-draft vaporizer comprising a hollow member arranged for its heating by the combustion of vaporized fuel discharged therefrom and providing a horizontally elongated cavity therein having an air inlet slot along its top and a vapor outlet slot along its side and a fuel inlet, and a means operable to clean the surfaces cf the member at and adjacent the vapor outlet slot While the burner is 1n use.

6. In a liquid fuel burner, a vaporizer comprising a member arranged for its heating and providing an elongated cavity therein having its longitudinal axis horizontal and provided with a side Vapor outlet and an air inlet and a liquidfuel inlet, said member comprising a pair of mutually opposed elements which extend from a horizontal plane through the vapor outlet and are unitarily secured together by means which permit their relative .expansions in directions parallel to said plane, means to continuously supply liquid fuel to and through lsaid fuel inlet, and means to utilize the fuel vapors issuing from the vapor outlet to supply a nre which is arranged for heating the member for the continued generation of fuel vapors therein.

7. In a liquid fuel burner, a down-draft vaporizer comprising a hollow member aranged for its heating by the combustion of vaporized fuel discharged therefrom and providing a horizontally elongated cavity therein having an air inlet slot along its top and a vapor outlet slot along its side and a fuel inlet, the side wall of the cavity providing an evaporation surface for wetting by the liquid fuel, and means Within Athe cavity QD- erative to distribute the received liquid fuel upon and along said evaporation surface adjacent said vapor outlet slot.

8. In a liquid fuel burner, a vaporizer comprising a hollow member arranged for its heating by the combustion of vaporized fuel discharged therefrom and providing a horizontally elongated cavity therein having an air inlet slot along its top and a vapor outlet slot along its side and a fuel inlet, the side wall of the cavity providing an evaporation surface for wetting by the liquid fuel, an evaporation vtray disposed inthe cavity longitudinally thereof and in spaced relation from the cavity vsides and arranged for the free overflow fall of liquid therefrom, and a Vdeflector means operative upon the liquid falling from the tray "to distribute the liquid upon the Acavity side Ywall above and below the vapor loutlet slot for its evaporation from said Wall.

9. In a liquid fuel burner, a vaporizer `comprising a hollow member :arranged for its heating by the combustion of vaporized fuel discharged therefrom and providing a horizontally elongated cavity therein having an air inlet at its top and a vapor outlet slot along its side and a fuel inlet, an evaporation tray disposed in the cavity longitudinally thereof and in spaced relation from the cavity sides to receive liquid fuel from -said fuel inlet and arranged for the free overflow :fall of liquid therefrom in `a line therealong, and a baille element disposed in the path of liquid falling from the tray to deflect liquid upon the cavity side wall adjacent the vapor outlet slot for evap-l oration from said wall.

10. A fluid fuel burner comprising a member arranged for its heating and providing an elongated cavity therein having its longitudinal axis horizontal and having air and fuel inlets and a side outlet for the discharge of the gaseous vmixture resulting from the mixing of the inlet air and fuel, said outlet comprising a horizontal slit, an open-ended tubular shell .enclosing said member longitudinally of said slit in spaced relation from the member .and provided with a bottom opening having its upper edge disposed substantially in the same horizontal plane with the slit and `arranged for the passage of the said gaseous mixture beneath said edge for its combustion along the outer shell surface, and a baille means `interposed Ain the path of discharge of the gaseous mixture from the outlet slit and inwardly of said shell edge for facilitating the mixing of 'air from within the shell with the gaseous mixture from the slit.

1,1. A fluid fuel burner comprising a member arranged for its 'heating and providing an elongated cavity therein having its longitudinal axis horizontal and having air and fuel inlets and a horizontal 4side outlet slit for the discharge of the gaseous `mixture resulting from the mixing of the inlet air and fuel, an open-ended tubular shell enclosing said member ,longitudinally of said slit in spaced relation .from the member and provided with a bottom `opening having its upper edge disposed substantially in the same horizontal plane Awith the slit and arranged for the passage of the said gaseous 'mixture beneath said edge for its combustion ,along the outer shell surface, and a pan member underlying the rst member and the shell and having its top edge disposed in a plane above the outlet slit of the first member.

12. In a, heater, a uid fuelburner comprising a member providing an elongated cavity therein having vits longitudinal axis horizontal and having air and fuel yinlets and .a horizontal side outlet slit for the'discharge of the gaseous mixture resulting from the mixing of the inlet air and fuel, an open-ended tubular shell enclosing said member longitudinally of said slit in spaced relation from the member and provided with a bottom opening vhaving its upper edge disposed substantially in the Asame horizontal plane with the slit and'arranged .for the passage of the said gaseous mixture beneath vsaid edge for its combustion along the outer shell surface, and a casing providing a combustion chamber and fittedly receiving the yshell through it and across its chamber to provide for the entry of airinto the chamber entirely-through the shelland Vprovided with a discharge outlet for the escape of combustion products therefrom.

EDWARD L. TORREY.

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