US3694135A - Flame retention burner head - Google Patents

Abstract

A flame retention burner head in which the flame retention baffle carries an annular ring on its outer periphery which extends downstream sufficiently to elongate the stationary vortices formed thereby. The atomizing nozzle of the burner is arranged to inject the fuel particles into the vortices, and peripherally spaced louvres on the ring are arranged to direct streams of air inwardly into the flame at the downstream end of the elongated vortices.

Description

United States Patent Dancy et al.

[54] FLAME RETENTION BURNER HEAD [72] Inventors: Julian H. Dancy; John A. Morrison,

both of Richmond, Va.

[73] Assignee: Texaco lnc., New York, NY.

[22] Filed: July 20, 1970 21 Appl. No.: 56,599

52 05.0. ..43l/265,43l/l83,431/351 51 Int. Cl ..F23q 3/00 [58] FieldofSearch ..43l/265,35l,354,l83

[56] References Cited UNITED STATES PATENTS Logan et al ..43 l/265 [4 1 Sept. 26, 1972 3,406,002 10/1968 Martin ..431/265 Primary Examiner-Carroll B. Dority, Jr.

Attorney-Thomas H. W haley,-Carl G. Reis and L. H. Phelps [57] ABSTRACT A flame retention burner head in which the flame retention baffle carries an annular ring on its outer periphery which extends downstream sufficiently to elongate the stationary vortices formed thereby. The atomizing nozzle of the burner is arranged to inject the fuel particles into the vortices, and peripherally spaced louvres on the ring are arranged to direct streams of air inwardly into the flame at the downstream end of the elongated vortices.

3 Claims, 10 Drawing Figures PATENTED8EP26 I972 SHEET 1 [IF 2 FIG. 2'

FIG. 3-

PATENTED EP I972 3.694.135

SHEET 2 or 2 FIG.

FLAME RETENTION BURNER HEAD The present invention relates to a burner head for oil burners and particularly to an improved flame-retaining type of burner head adapted to effect improved combustion of fuel.

In the type of burner with which the present invention is concerned, oil under pressure passes thru an atomizing nozzle, a stream of air being forced against the oil particles or droplets to form an intimate, combustible mixture.

Such equipment desirably is designed to provide for the intermixture of the air and the oil particles in such a way that the combustion zone is maintained in the burner head instead of being blown out so that a selfsustaining and controlled combustion reaction takes place.

i Combustion is effected in a burner head comprising an elongated casing or tube which conducts a continuous stream of air blown therethru from the rear by a suitable air pump or blower. The conventional burner head or casing contains an atomizing nozzle carried on an internal axially extending oil supply pipe'which is supplied with oil under pressure. Ignition means, usually carried by the pipe, comprises suitable electrodes extending into the combustion area just beyond the atomizing nozzle in the combustion area.

The flame retention baffle is arranged transversely of the air stream, occupying a substantially annular sec tion coaxially of the burner tube just beyond the atomizing nozzle. A central aperture in the baffle admits andaccommodates the spray discharge cone from the nozzle. The outer periphery of the annular baffle being spaced a substantial distancefrom the inner wall of the tube allows for a large flow of air thereabout. Also the baffle is frusto conical in shape, its base being open and facing in a downstream direction. This, of course, tends to facilitate air flow without excessive upstream turbulence.

The present invention contemplates a flame retention baffle, comprising a transverse annular plate combined with a marginal annular ring which extends in an axial direction with respect to the burner tube, said ring making an obtuse angle with the transverse plate. As a result, the eddies set up by the transverse plate are elongated and retained more effectively and can be controllably supplied with air as will hereinafter be more fully described.

Referring now to the drawing wherein a preferred embodiment of the present invention is described in greater detail,

FIG. 1 represents a vertical, longitudinal section thru a burner head constructed in accordance with the present invention.

FIG. 2 is an elevational view of said burner head taken, as viewed from the right in FIG. 1.

FIGS. 3 to 6 are more or less diagrammatic fragmentary representations showing the action of the elements within the burner head upon air and fuel streams and upon flame conformation; FIGS. 3 to 5 being more or less fragmentary sectional elevations taken diametrically thru the head and FIG. 6 being the end or transverse view illustrating the transverse pattern of the flame, taken on the line 66 of FIG. 5.

FIGS. 7, 8, 9 and 10 show end and side elevations of two modified flame retention baffles constructed in accordance with the present invention.

In the drawings the burner head comprises a cylindrical tube 10 associated with conventional blower, oil pump, controls and supporting mechanism (not shown), which provide a substantial oil supply pipe 12, mounted centrally and axially of the tube 10 and bearing on the extremity thereof of an atomizing nozzle 14. Also extending into the tube and mounted on the pipe 12 by means of support 16 are ignition members 18 terminating in a pair of electrodes 20 which, in turn, extend just ahead of the atomizing nozzle in the path of the spray. A predetermined, substantial flow of air under pressure is passed thru the burner tube 10 in the direction of arrows 22, by a conventional blower, not disclosed, and out past the nozzle 14 and thru the outlet of the burner tube.-

The present invention specifically involves a flame retention head including a transverse plate 24 and an axially extending annular ring 26 in a frusto conical configuration in order to minimize undesired turbulence in the main air stream thru the burner tube. The term transverse" as used herein is intended to include some relatively moderate degree of frusto conical arrangement, for example, less than 45 with respect to the radius of the tube. The ring 26 extends at somewhat of an obtuse angle with respect to the transverse plate 24 (as measured in an axial-radial plane). Thus the term axially extending as used herein with respect to the ring 26 is meant approximately parallel to the axis of the tube and with a divergence therefrom less than 45 outwardly with respect thereof.

The flame retention baffle formed by the plate 24 and the ring 26 is shown coaxially of the burner tube 10, occupying an annular coaxial portion of the cross section thereof, the central portion being open to receive the spray from the atomizing nozzle 14 and the outer periphery being spaced substantially inwardly from tube 10 to pennit a substantial peripheral flow of air.

The peripheral stream of air is controlled by means of a choke plate 28 which adjusts the stream for purposes to be hereinafter described.

Thus control of the peripheral flow of air also enables inward flow direction of a portion of the air stream by means of louvers 30 and 32.

Entirely apart from the flame controlling the function of which is to be described later in greater detail, the present invention provides a practical and useful mechanical structure for mounting, erecting and supporting the entire flame retention head or assembly. This is accomplished by struts 34 mounted on or welded to collar 36 which embraces the spray nozzle 14 and may be fixed thereto by set screw 38 or any other equivalent means. Struts 34 extend axially into contact with the margin of the transverse plate 24 to which they are welded. From this point they extend radially outwardly as at 40 to support the choke plate 28.

Support of the choke plate is effected by machine screws 42 and spacing tubes or collars 44. The collars 44 thus space the choke plate 28 from the supporting struts 40 a predetermined distance and are held in place by the machine screw 42 and washer and nut 46. Optionally, the strut component itself may be threaded, eliminating the nut component 46. As a result, therefore, the entire internal assembly may be inserted from the rear of the burner tube in a conventional manner after appropriately adjusting the choke plate spacing from the various parts. A struck out tab 48 may be provided at the end of the tube as a limit stop for this insert.

Referring now more specifically to FIGS. 3 to 6, the first of these is intended to indicate typical vortex formation 52 on the downstream side of the conventional transverse flame retention ring 50.

FIG. 4 contrasts the effect of the annular ring 26 extending at an obtuse angle from the edge of the plate 24, for lengthening the vortices 52. In both figures, the spray pattern represented by the dotted lines 54 clears the central aperture in the plate 50 and intermingles with the air in the standing vortices to effect complete admixture.

With the foregoing theoretical explanation, reference is again made to the specific structure of the flame retention baffle constructed as illustrated more clearly in FIGS. 1, 2, 5 and 6.

Transverse plate 24 is slit and deformed'slightly as at 25 to provide air admission louvers which are herein referred to as air sheath louvers since their function is only to provide a sheath of air across the surface of the plate 24 to prevent direct flame impingement thereon. In other words, a layer of fresh, incoming air circles as a skin on the flame exposed downstream surface of plate 24 andmoves essentially parallel thereof, primarily to resist deposition of pyrolytic carbonaceous solid material from the-flame. These louvers, have therefore only a-relatively narrow gap and direct the air essentially parallel to the surface of the plate 24.

The standing vortices 52 of air internally of the baffle ring 26 are continually swept by the spray of particles from the atomizing nozzle which are entrainedtherein to form combustible mixture which continuously burns in front of the transverse plate 24. FIGS. 5 and 6 not only illustrate the effect of this action on the flame formation but show the supplemental effect of lateral air injection in the form of the plurality of peripheral jets. This is caused by jet air louvers 30, which in combination with the action of the choke plate 28, tend to divert the annularly spaced radial jets of air into the flame toward the downstream portion of each vortex. Thus in FIGS. 5 and 6 the arrows 56 indicate the spaced radial jets of air blown into the flame. The louvers 30, accordingly, are so directed as to eflect essentially jets of air impinging and piercing the flame. Alternate louvers such as 32 are provided with a relatively narrow aperture and so directed that inward air moves substantially parallel to the inner surface of the ring 26, and defined as sheath air louvers.

It is to be particularly observed that the foregoing functions of the device are dependent upon the proper maintenance of air pressures, whichwill be apparent to anyone skilled in the art, in view of the foregoing explanation. For example, the so-skilled operator would not impose air velocities so excessive as to shrink the vortices and weaken flame holding, nor would be impose such air pressures via the louvers 30 as to collapse the flame.

On the contrary, operating the present equipment so that the streams of jet air enter the downstream portions or sections of the standing vortices without destroying their effectiveness enables realization of certain improved and desirable results. Among these are a significant improvement in smoke-free performance, realization of a stable, short flame length,

improved efficiency of combustion, and, rapidly achieved, clean combustion. The flame retention feature of this burner head enables achieving a relatively quieter pulsation resistant flame and reduced sensitivity to variationsof flue draft as compared to non-flame retention burner heads. The lengthening of the standing vortices as achieved by annular ring 26 improves the resistance of the flame retention baffle 24 to flame blow-off. The general arrangement of the burner head provides additional convenience and simplicity of assembly, maintenance and adjustment of the equipment.

-It is to be noted that FIGS. 7 and 8 show in greater detail the air control baffle of FIGS. 1 and 2.

FIGS. 9 and 10 disclose a variation in baffle ring design wherein the sheath air louvers on the axially extending ring 26 are located, as at 60, slightly to the left or what might be said to be upstream of the jet air louvers 62. Again, the jet air louvers are shaped to direct a series of jets of air into the vortices in the downstream portion thereof while the sheath air louvers 60 direct a relatively small amount of air along the inner surface of ring or collar 26 to protect against flame impingement.

We claim:

1. In an oil burner having a burner tube with means for forcing air under pressure through said burner tube, a fuel atomizing nozzle, and a flame retention means coaxially and transversely arranged within said burner tube and comprising a right conical frustum having an open base positioned adjacent the outlet of said burner tube for creating standing vortices in the air stream, the

upstream end comprising a transverse plate and having a central orifice for the passage therethrough of atomized fuel from a spray head, said frustum being mounted in predetermined coaxial relationship and supported by a plurality of struts connected with said atomizing nozzle, said transverse plate being provided with a series of louvers constructed and arranged to conduct a relatively thin sheath of air annularly along the downstream surface of said transverse plate, said frustum being provided adjacent its open base with a plurality of annularly spaced louvers arranged to direct a series of jets of air into the flame at the downstream end of said vortices, and annularly along the downstream face of said frustum adjacent said open base.

2. In an oil burner as defined in claim I, a coaxial annular choke ring spaced downstream from said frustum, and said plurality of struts extending to and being connected to the upstream periphery of said frustum and having the portions radially outwardly extending therefrom, and combination spacer and fastener means'connecting said choke plate with said radially outwardly extending struts and supporting said choke ring in fixed space relationship thereto so that the assembly of said nozzle and frustum are supported coaxially within said burner tube so that it may be inserted and extracted as a unit.

3. In an oil burner as defined in claim 2, said struts being joined to said atomizing nozzle by releasable collar means.

Claims (3)

1. In an oil burner having a burner tube with means for forcing air under pressure through said burner tube, a fuel atomizing nozzle, and a flame retention means coaxially and transversely arranged within said burner tube and comprising a right conical frustum having an open base positioned adjacent the outlet of said burner tube for creating standing vortices in the air stream, the upstream end comprising a transverse plate and having a central orifice for the passage therethrough of atomized fuel from a spray head, said frustum being mounted in predetermined coaxial relationship and supported by a plurality of struts connected with said atomizing nozzle, said transverse plate being provided with a series of louvers constructed and arranged to conduct a relatively thin sheath of air annularly along the downstream surface of said transverse plate, said frustum being provided adjacent its open base with a plurality of annularly spaced louvers arranged to direct a series of jets of air into the flame at the downstream end of said vortices, and annularly along the downstream face of said frustum adjacent said open base.

2. In an oil burner as defined in claim 1, a coaxial annular choke ring spaced downstream from said frustum, and said plurality of struts extending to and being connected to the upstream periphery of said frustum and having the portions radially outwardly extending therefrom, and combination spacer and fastener means connecting said choke plate with said radially outwardly extending struts and supporting said choke ring in fixed space relationship thereto so that the assembly of said nozzle and frustum are supported coaxially within said burner tube so that it may be inserted and extracted as a unit.

3. In an oil burner as defined in claim 2, said struts being joined to said atomizing nozzle by releasable collar means.

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