US3730438A - Fuel burner nozzle - Google Patents

Abstract

In a pressure atomized oil burner having air louvers to swirl primary air, a long narrow flame is produced without reducing heat release by using a nozzle tip having cylindrical ducts drilled at a compound angle in the direction of the air swirl in addition to the main cone angle.

Description

llnited States Patent 1 Howe [ FUEL BURNER NOZZLE [75] Inventor: Frank C. Howe, Bakersfield, Calif.

[73] Assignee: Shell Oil Company, New York,

[22] Filed: June 3, 1971 [21] Appl.No.: 149,679

52 'u.s .cl..-...... ..239/490 51 Int.Cl. ..B05b 1/34 [58] FieldofSearch.. ..239/,490,567,596,

[ 56] I References Cited .1 UNITED STATES PATENTS 3,279,705 10/1966 Stiefel ..239/49O [4 1 May 1,1973

3,452,933 7/1969 Hakluytt ..239/567 X 1,408,521 3/1922 Lathrop ..239/490 2,462,704 2/1949 Zink ..239/596 X Primary ExaminerM. Henson Wood, Jr. Assislant Examiner-Reinhold W. Thieme Attorney-Theodore E. Bieber and-Harold L. Denkler [57] ABSTRACT In a pressure atomized oil burner having air louvers to swirl primary air, a long narrow flame is produced without reducing heat release by using a nozzle tip having cylindrical ducts drilled at a compound angle in the direction of the air swirl in addition to the main cone angle.

6 Claims, 3 Drawing Figures PATENTEDHAY H y 3.730.438

' F. C, Howe INVENTOR FUEL BURNER NOZZLE BACKGROUND OF THE INVENTION The present invention relates to a fuel nozzle tip. More particularly, the invention concerns itself with pressure atomized fuel oil burner nozzle tips for use in a narrow firebox.

It is common practice to atomize fuel used in fireboxes in order to effectively disperse the fuel into a fine mist for more efficient combustion. In one approach used to steam atomize fuel prior to burning, the primary and secondary jets are disposed concentric to and outward from a central fluid opening in the nozzle such that the primary steam jets are directed tangentially to and against the circumference of the fuel to be atomized flowing from the central opening. The secondary steam jets which are disposed concentric to and outward from the primary steam jets are utilized for more complete atomization of the fuel prior to combustion.

A second approach has used a mixing chamber with tangential slots which impart a whirling action to the fuel by discharging steam tangentially about the circumference of the fuel discharge passage.

Nozzles of the above mentioned design, while providing atomization of the'fuel, will not produce a narrow flame to avoid flame impingement of the tubes in a narrow firebox.

SUMMARY OF THE INVENTION Accordingly, this invention provides an advantageous approach whereby a long narrow flame is produced by an unique method of swirling the pressure atomized fuel prior to combustion for use in a narrow firebox without loss of heat release by the burner.

The above advantages have been attained in the present invention by the drilling of the cylindrical ducts at a compound angle in the direction of the air swirl in addition to the main cone angle. The main cone angle is an included angle defining an outwardly directed cone with its apex in the nozzle tip.

DESCRIPTION OF THE DRAWING The above noted and other advantages of the present invention will be understood from the following description taken with reference to the accompanying drawing. In describing the invention in detail, reference will be made to the drawing in which like reference'numerals designate like parts throughout corresponding views in which:

FIG. 1 is a view in side elevation of the device;

FIG. 2 is a centrallongitudinal section through a nozzle tip for practicing my invention; and

FIG. 3 is a view in front elevation of the device shown in FIGS. 1 and 2, showing the outlet side of the nozzle tip.

DESCRIPTION OF PREFERRED EMBODIMENT Referring more particularly to the drawing, 1 indicates the nozzle body in which an internal passageway 2 is formed such that it is symmetrical about longitudinal centerline 44 of nozzle body 1 and is closed on one end by a hemispherical chamber and is open at the opposite end for entry of pressure atomized fuel into nozzle body 1. An external truncated cone O ternal passageway 2 with external air swirl A, and

piercing the external truncated cone formed by external surface 5 are formed such that cylindrical ducts 3 are equally spaced along the circumference 6 on external surface 5 and projecting inwardly such that a plane extending along a longitudinal centerline of cylindrical ducts 3 would form a first acute angle of 28 to 32 at the intersection of longitudinal centerline 4-4 of nozzle body '1 forming the main cone angle. In addition to the main cone angle, an acute lead angle of 8 to 12 is used to position cylindrical ducts 3 such that a compound angle is formed in the direction of external air swirl A at the closed end of nozzle body 1.

OPERATION The operation of the above disclosed arrangement is as follows. As pressure atomized fuel enters the nozzle body at internal passageway 2 and passes through ducts 3 for combustion, a swirling action is imposed on the pressure atomized fuel by the compound angle formed by drilling of the ducts 3 at the main cone angle and lead angle simultaneously. For example, a main cone angle of approximately 30 degrees and lead angle of approximately 10 in combination with a nozzle body cone angle in the range of 45 has been found to produce a long narrow flame without reduction of heat release of the burner. The lead angle is drilled in the direction of the external air swirl A which can be either clockwise or counterclockwise, but in this case is counterclockwise. The main cone angle, lead angle, and nozzle body cone angle are important in order that a long narrow flame be produced during combustion of the pressure atomized fuel in a narrow firebox without reducing heat release and avoiding flame impingement of the tubes. Nozzle designs with reduced main cone angles and the same nozzle body cone angle but no lead angle were tested by heat release was substantially reduced even though a long narrow flame resulted.

I claim as my invention: 1. A nozzle for swirling pressure atomized fuel to produce a long narrow flame, comprising:

a nozzle body; an internal passageway in said nozzle body open at one end and closed by a hemispherical chamber at the other end, said passageway being symmetrical about the longitudinal centerline of said nozzle body; the nozzle body having an external surface at the closed end in the form of a truncated cone forming a nozzle body cone angle having its apex forward of said closed end and symmetrical about the longitudinal centerline of said nozzle body; and a plurality of cylindrical ducts in said nozzle body piercing the external conical surface and communicating with said hemispherical chamber, each of .which is positioned with a main cone angle and lead angle.

2. The nozzle of claim 1 wherein said nozzle body cone angle is an acute angle of 45 to 50 degrees. a 3. The nozzle of claim 1 wherein said main cone angle is an acute angle of 28 to 32.

5. The nozzle of claim 1 wherein said plurality of cylindrical ducts are equally spaced.

6. The nozzle of claim 1 wherein said lead angle is 4. The nozzle of claim 1 wherein said lead angle is an 5 positioned in the direction of external air Swirl acute angle of 8 to 12.

Claims (6)

1. A nozzle for swirling pressure atomized fuel to produce a long narrow flame, comprising: a nozzle body; an internal passageway in said nozzle body open at one end and closed by a hemispherical chamber at the other end, said passageway being symmetrical about the longitudinal centerline of said nozzle body; the nozzle body having an external surface at the closed end in the form of a truncated cone forming a nozzle body cone angle having its apex forward of said closed end and symmetrical about the longitudinal centerline of said nozzle body; and a plurality of cylindrical ducts in said nozzle body piercing the external conical surface and communicating with said hemispherical chamber, each of which is positioned with a main cone angle and lead angle.

2. The nozzle of claim 1 wherein said nozzle body cone angle is an acute angle of 45 to 50 degrees.

3. The nozzle of claim 1 wherein said main cone angle is an acute angle of 28* to 32* .

4. The nozzle of claim 1 wherein said lead angle is an acute angle of 8* to 12* .

5. The nozzle of claim 1 wherein said plurality of cylindrical ducts are equally spaced.

6. The nozzle of claim 1 wherein said lead angle is positioned in the direction of external air swirl.

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