US2579293A - Pilot for vaporizing burners - Google Patents

Description

J. L. BREESE PILOT FOR VAPORIZING BURNERS Dec. 1s, 1951 Filed Aug. 29, 1947 OIL LEVEL um. m

Patented Dec. 18, v1195i yJames L. Breese, Santa Fe, N. Mex., assignor to Breesre Burners, Inc., Santa Fe, N. Mex., a'co'rporation of Delaware imputation August 129, meufs-ferial No. 771,203

Y2 Claims. 1

-My invention relates to an improvement in liquid fuel burners and hasfor one purpose to .provide an improved mechanism for maintaining a minimum or loW turned-down re.

Another purpose is to Aprovide an improved pilot piece or housing for vliquid fuel burners.

Another purpose is 'to provide an improved method of low-fire or pilot combustion.

AAnother purpose is to provide improved means for burning and `for hy-droxylating liquid fuel in a -pot type burner when the burner lis supplied with liquid fuel at 'a minimum vor pilot rate.

:Another purpose is to provide an improved securing means for removably securing a pilot housingin position in a'burner.

Another purpose is to provide a pilot ystructure adapted to operate, and 'to maintain a pilot flame, at a 'rate or rates of `fuel flow substantially less than the operating rates 'of .pilot :structures heretofore available.

Other purposes will appear from time to Ytime in the course of the specification and claims.

I illustrate the invention more or less diagram-V matically in the accompanying drawings where- Fig. l is a vertical section;

Fig. 2 is an enlarged vertical section;

Fig. 3 is a horizontal section, on 'the line '3-3 of 'the Fig. 2; and

Fig. 4 is a section taken on the line 'll- "4 of Fig. 2.

Referring to the drawings, I generally 'indicates `an outer housing having a `plurality Kof feet 2 between which are air :inflow spaces 3. :The housing is partly closed by a Yhorizontal 4partition 4 centrally apertured as at 5. 5 is an angle ring which receives the upper outwardly extending flange 8of a burner pot l. 9 indicates an upper portionof the housing I, which Vserves as a cornbustion chamber, or a heat radiating member. Any suitable draft means, vnot'hereinsho'wmin'ay be provided for disposing of the heated 'gases 'and by-products of combustion. :One-end of the "pot is Vpartially closed by a centrally aperturedfflame ring I0. The pot vis Vlshown as having a l'sligl'itly concave bottom 'or c'los'ed'end 'I'I and agexrerally cylindrical side wall lI2 provided with a plurality of primary air inlet apertures I3, circumferentially spaced aboutthe -wall I2 fand located at various distances above the pot bottom. A lio;- uid fuel is supplied to the pot along the pipe "I6, megane of now -bing cri-troiieuhyfany suitable control 'means 'generally indicated as 'Ij'l. "I illus-v ary apertures 25.

trolling vthe-iiow of hiel along the pipe It. Howiever, Sit will be understood that anysuitable lcontrol lmeans, manual or automatic, may be provided for varying the rate of flow of vliquid fuel along the pipe I6 or for maintaining a 'uniform rate of now, when a uniform rate `is desired.

It will be understood that in pot type burners of 'the lpresent type, a liquid hydrocarbon is vaporized by the heat of combustion taking place in or labove the pot. The liquid hydrocarbon is admitted to `the interior .of the pot fand -is initially partially "vaporized by the heat of combustion taking place in the pot. As the liquid hydrocarbon is vaporized in the `pot it Yrises and is -surrounded by va film of secondary air. The radiant heat from the ensuing complete combustion supplies the remainder of the additional heat necessary to vaporize all of the liquid hydrocarbon. rIl'lere is a differentiation in action between the s'o-called primary air and the so-called secondary air admitted to the interior of the pot. fV/"ith reference to the present structure, the air enteringthrough primary apertures I3, Ahas a different action than the airentering through the second- All Of the oxygen in the air entering through the yprimary apertures I3 is fully consumed in the process of hydroxylation. I provide any suitable secondary kair inlet apertures such as are shown at 25. stood that secondary air is vadmitted through the apertures l25, to form with primary mixture a hal mixture which is burned at or beyond or above the top `or open end of the pot.

I locate a pilot member or piece 'which rests upon the bottom I I of the pot and which should snugly abut against a lower part of the lpot side wall. It is shown as surrounding the space 'to which liquid lfuel uis delivered by the duct or ypipe I6. The pilot piece which I indicate generally as 36 'is Sshown as having two inwardly converging side Walls 3! with top flanges `32. The lower edges'ofthe side walls 3l snugly engage the upper surface of the pot bottom I I. The side walls have flanges 33 at theirouter ends which engage the inner surface of the pot side wall. The Vpilot'side walls 3| are connected by an inner end wall 34 which has an outlet 35 connecting the interior of thepilot piece With the interior of the rest of thepot. In the structure herein shown I illustrate a sheet metal pilot piece. derstood that it may be cast or otherwise suitably formed. In the particular structure herein illustrat'ed I show' an intermediate plate 3B `the outer edges offwhich overlie 'and conform to the ilange4 3'2.l 'Positioned above th'eplate 36 is an upwardly It will be undex-,

It will be un.

domed or offset cover plate 3'1 which, with the plate 36, forms a plenum chamber. The function of this chamber is to supply air to the liquid fuel vaporized within the pilot piece 30. I provide an air inlet duct 38 the outer end of which extends as at 39 through an appropriately formed aperture in the pot side Wall I2. 40 is a nut adjustable on the screw threaded end 39 of the duct 38. 4I is a bracket on the duct 38, located within the pot. It carries a suitablethrust member, such as the screw 42, which may be employed adjustably to direct a controlled or predetermined thrust against the inner face of the pot side wall I2. By using the structure above described, and by properly adjusting the nut 46 and the screw 42, the pilot piece may be held firmly in the position in which it is shown in Figures 1 and 2, with a substantial elimination of leakage about the edges of the pilot side walls 3 I. Y

Air from the space between the housing I and the pot I2, fiows through the duct 38 and into the plenum chamber 37. The air is admitted t0 the space about the pot through the aperture 5. If desired a booster motor and fan may be positioned in the aperture, or other means may be employed for maintaining a suitable air pressure about the pot.

Air from the plenum chamber flows downwardly into the space within the pilot piece 30,

through aV plurality of primary air inlets 45.

These are shown as arranged in a series of rows, Ibut their particular size and arrangement may be varied. They provide primary air for the initial hydroxylation of the liquid hydrocarbon fuel which flows through the pipe I6 into the interior of the pilot piece 30. The final or secondary air supply is shown as provided by a single row of secondary air inlets 46 positioned adjacent the outlet 35. It will be noted that I show secondary air inlets which are both larger and more closely spaced than the primary air inlets and which direct a substantial concentration of secondary air adjacent the point of escape of the mixture from the interior of the pilot housing 39. Thus the liquid fuel ows across the bottom of the pilot housing, in a very thin stream, and, at minimum rates of combustion, almost drop by drop. I may find it advantageous to delay the flow of the liquid fuel by providing a somewhat flattened area, shown at 50 in the bottom of the pot and located just beneath and inwardly of the point of Ydelivery of the liquid' fuel from the pipe IIS.

It will be understood that whereas I have described and shown a practical and operative device, nevertheless many changes may be made in size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to the specific showing herein. For example I may employ or omit the flattened pot bottom surface 56. I may substantially change the size and arrangement and shape of the apertures 45 and 46. And I may use sheet metal or other suitable metal for forming the pilot piece herein shown.

The use and operation of the invention are as follows:

I provide a pilot piece which receives its liquid fuel from the normal fuel inlet of a pot type burner. I avoid the use of a pool or dam or depression by employing the bottom of ,the pot itamazes Y self as a trough or fiowing surface over which the fuel iiows. Under some circumstances it is advantageous to move the oil by gravity as rapidly as possible from the inlet pipe to the center of the burner. In that event I omit the flattened position 5B. Under other circumstances it may be desirable somewhat to slow down the flow of the fuel. In that event I may employ the nattened surface 50. I find it advantageous to prevent any damming or pool formation which would cause a clogging with asphalt or hard carbon. I find that in the ordinary burner bottom, where the slant of the pot is less than one-eighth inch to the foot, the oil spread is unsatisfactory. I therefore generally use the small trough surface or depression 50 immediately along the center of the plate 36. By using it the oil is rapidly moved down through the center in a thin stream. By the time it reaches the secondary air holes 46, it has been completely vaporized and hydroxylated. And under no circumstances do I permit the formation of a pool of liquid fuel.

In hydroxylating the pilot fuel I find it important to delay the formation of a defined flame in the pilot zone, which could result in coking the liquid hydrocarbon, with a resultant deposit of carbon and ultimate stoppage of the oil flow. I so arrange and proportion the apertures 45 as to provide air in insucient amounts to produce a flame. Y The llame does not begin until the fuel or mixture has reached the zone of admission of secondary air, at whichtime all liquid hydrocarbon on pilot fire has been completely vaporized and hydroxylated.

To summarize the action of my pilot structure,

I move a thin layer of liquid fuel at a substantial rate of flow, through a zone in which it receives primary air in a relatively scant quantity, insufficient for flame formation. The fuel is Vaporized in response to combustion at, near, or beyond the inner end of the pilot piece 30. Flame does not begin u ntil the Yprimary mixture receives the secondary air. I thus employ, in effect, a gravital feed or flow of fuel, along the relatively narrow trough 50, by which the liquid moves with substantial rapidity until vaporized. One advantage of the structure is that it can be supplied with liquid fuel with a relatively low head of liquid.

I claim:

1. In a pilot housing for pot type liquid fuel burners, inwardly converging side walls having end portions formed and adapted to engage the inner surface of a burner pot side wall, bottom edge portions adapted to engage and conform to the burner bottom, and an inner end wall uniting the inner ends of said side walls, and'having a flame outlet, a plenum chamber overlying and closing the space between said pilot side walls and an air inlet duct extending from said plenum chamber upwardly and adapted to extend outwardly through the side wall of the pot, and

members on said air inlet duct adapted to thrust said pilot housing downwardly against the potu bottom and outwardly against the pot side wall, said members including a pot wall engaging abutment adapted to be placed exterior to the pot and an offset abutment on said air inlet duct, adapted to engage the inner face of the pot side wall.

2. The structure of claim 1 characterized in that the pot wall engaging abutment and the olfset abutment on the air inlet duct are mounted forV adjustment along the air inlet duct whereby,

when they are tightened, the pilot vhousing is.

thrust downwardly and outwardly against the potwall.

JAMES L. BREESE.

REFERENCES CITED .Number Name Date Valjean Aug. 16, 1927 Breese, J1' Feb. 19, 1929 Number 6 Name Date Jenson June 20, 1939 Breese Aug. 8, 1944 Lvar Feb. 20, 1945 Lvar Jan. 15, 1946 Miller et al Aug. 31, 1948 Greer, Jr. Nov. 2, 1948 Huston Jan. 25, 1949 Huston et a1 Jan. 25, 1949 Stempel et al. Apr. 5, 1949 Cargle et a1 Jan. 9, 1951

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