US3409383A - Flame forming burner construction - Google Patents

Description

9 T. s. VOORHEIS 3,409,383

FLAME FORMING BURNER CONSTRUCTION Filed May 9, 1967 INVENTOR- TEMPLE 8. VOORHEIS tmmsama W1 mm/Q A TTO RNEYS United States Patent 3,409,383 FLAME FORMING BURNER CONSTRUCTION Temple S. Voorheis, Palo Alto, Calif., assignor to Coen Company, Burlingame, Calif., a corporation of California Filed May 9, 1967, Ser. No. 637,123 2 Claims. (Cl. 431-474) ABSTRACT OF THE DISCLOSURE A combustion chamber wall defining a throat opening that is shaped in accordance with the flame shape desired, which in turn is dictated by the combustion chamber configuration. A fuel nozzle formed with plural fuel outlet openings so arranged and oriented to cooperate with the asymmetrical burner throat to form an asymmetricallyshaped flame in a combustion chamber.

The present invention provides an improved burner for forming a flame for firing large boilers in an extremely eflicient manner with a single burner. A burner according to the invention substantially fills the combustion chamber of the boiler with flame and the flame is shaped so as to avoid direct impingement onto the interior walls of the combustion chamber. These advantages are achieved without utilizing excessive air supply and without providing plural openings or fuel nozzles in the boiler furnace wall.

In the foregoing environment the invention provides a burner throat opening that is formed adjacent the lower portion of the boiler combustion chamber wall and midway between the lateral walls of the combustion chamher. The burner throat terminates at the interior of the combustion chamber in an opening that is symmetrical relative a vertical axis and asymmetrical relative a horizontal axis. The amount or degree of asymmetry is established so that the lower portion of the flame path created by the burner moves adjacent the floor of the combustion chamber and adjacent the opposite wall thereof, whereas the upper portion of the flame path moves upwardly in the furnace and adjacent the wall in which I the throat opening is formed.

In conjunction with the novel burner throat of the invention, a fuel injecting nozzle is provided. The nozzle has plural drilled openings that are sized and oriented relative the throat to produce the desired flame shape. "By combining appropriate orientation and size of the nozzle openings with the improved throat configuration, excellent efficiency is achieved because the fuel nozzle openings that direct atomized fuel toward the surface of the throat are so proportioned and are formed at such angle that direct impingement on the throat surface is avoided along any axis. Thus, buildup of carbon deposit on the throat is eliminated.

An object of the present invention is to provide a single burner for firing a combustion chamber, which burner provides a flame pattern having a predetermined shape that substantially fills the combustion chamber without permitting direct flame impingement on the combustion chamber wall opposite the burner throat.

Another object is to provide a burner of the type alluded to above which is particularly suitable in firing burners having a substantial height and width to depth ratio.

These and other objects will be more apparent after referring to the following specification and accompanying drawings in which;

In the drawings:

FIGURE 1 is a cross-sectional elevational view of a boiler combustion chamber employing the present inven- 1 tion and taken through the center of the burner throat;

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FIGURE 2 is a cross-sectional plan view taken through the center of the burner throat;

FIGURE 3 is a view of the burner throat as seen from the interior of the combustion chamber;

FIGURE 4 is an elevational view in cross-section of a fuel nozzle taken at greatly enlarged scale and along line 44 of FIGURE 5;

FIGURE 5 is an end view of the nozzle taken along line 55 of FIGURE 4; and

FIGURE 6 is a horizontal cross-sectional view taken along line 66 of FIGURE 5.

Referring more particularly to the drawings, reference numeral 12 indicates a fragment of the front wall of a boiler combustion chamber, which combustion chamber also has a rear wall 14 and a floor 16. Mounted adjacent or embedded within the walls 12 and 14 are water tubes (not shown), which in accordance with conventional boiler technology, communicate with a header for supplying water to the steam forming water tubes. The boiler wall 12 includes an outer face 18 and an inner face 20. A burner throat 22 is formed in wall 12 between the outer and inner faces.

Throat 22 at the outer face 18 defines a circular orifice indicated at 24. The throat, at inner wall face 20, defines an orifice of distorted oval form indicated at 26 in FIG- URE 3, the distortion being a somewhat flattened segment at the bottom (see reference numeral 28 in FIG. 1). Flattened segment 28 functions to avoid impingement of flame directly onto floor 16. The upper segment of orifice 26 is curved continuously upwardly as at 30 to permit the flame pattern to rise rapidly and adjacent to inner surface 20 of front wall 12. As can be seen at FIGURE 2, the throat is symmetrical with respect to a horizontal axis and the wall surfaces are flared out widely at 32 for permitting the flame to spread laterally of the burner opening so that the flame approaches the lateral combustion chamber walls.

Cooperating with the specially configured burner throat opening is a nozzle assembly that includes a nozzle cap 42 supported centrally of orifice 24 by a fuel supply pipe 44. Pipe 44, in accordance with conventional practice, supplies atomized fuel to nozzle cap 42. Referring to FIGS. 4 and 5, nozzle 42 includes a frustoconical wall 46 in which are provided, for example by drilling, a plurality of fuel passages which have sizes and orientations arranged in respect to the specific shape ofthe burner throat to form the flame as desired. More specifically, the nozzle cap has a pair of upper fluid passages 48a and 48b formed through wall 46 at an angle that corresponds with the shape of the throat at segment 30. Because portion 30' of the throat flares out at a-substantial angle, fuel passages 48a and 48b are drilled at a corresponding large angle with respect to the central axis of the nozzle structure. Formation of two holes 48a and 4811, rather than one hole of an area equal to the sum of areas of the two holes. assures delivery of a desired quantity of fuel at a sufficiently low kinetic energy level to avoid flame impingement on the wall of the combustion chamber.

Nozzle cap 42 is further provided with lateral fuel orifices 50 and 52 which are formed at an angle corresponding to the configuration of throat surface portion 32. Because surface portion 32 is flared out by a substantial amount, the angle at which passages 50 and 52 are formed is substantial. Accordingly, the lateral spread of the flame as indicated at 54 in FIG. 2 is substantial so that the flame is shaped to substantially fill the combustion chamber. Passages 50 and 52 are formed at a suflicient angle that the fuel issuing therefrom, even though it has substantial energy, does not impinge on the combustion chamber walls.

A trinity of lower fuel passages 56a, 56b and 56c is provided in nozzle cap 42. The lower passages are formed the burner throat. In order to reduce the momentum or kinetic energy of the fuel supplied in the lower sector of the furnace, thereby avoiding direct impingement of flame onto floor 16, the fuel is supplied through three passages 56a, 56b and 560 which have a total cross-sectional area sutficient to fire adequately the lower portion of the com.- bustion chamber but which have individual cross-sectional areas smaller than the remaining fuel passages.

The nozzle cap 42 depicted in the drawing is somewhat.

simplified for clarity. In actual practice better flame dis; tribution is provided by a cap having more fuel passages therein, such passagesbeing formed between those specifically shown and having angles intermediate the angles at which the passages on either side'of the passages in question are drilled;

It will be observed-from the specific boiler construction depicted in the drawing that the distance between front wall '12 and rear wall 14, i.e., the depth of the furnace, is short. Direct impingement of flame on wall 14 is avoided because each fue'l'passag'e' is drilled at-a substantial angle with respect to the central axis of 'the nozzle. The angle at which the individual fuel passage is formed depends on the desired fla'me shape which also dictates the configuration of the throat surfaceKT-hus, it can be seen that by proper selection 'of nozzle passage configura tion andthroat shape, the combustion chamber can be substantially totally filled with flame and direct impingemerit of any part of th'e'flameonto any part of the combustion chamber wall is avoided. Because the fuel injec tion pattern is substantially dictated by the configuration of the fuel passages in nozzle 42 and because'the air inflow pattern is determined by the shape of the throat opening, the desired uniform flame pattern is achieved by use of thepresent invention. a I

Thus,'it will be seen that the present invention provides an efficierit single burner system for efficiently firing boilers that have a large ratio of height and width to depth. The present invention afiords such burner in a low-cost, maintenance-free unit which can be installed in ,both existing and new boiler constructions.

Although one embodiment of the invention has been shown and described, it will be obvious that other adaptations and modifications can be made without departing from the true spirit and scopeof the invention.

What is claimed is:

1. In a boiler including a wall having an inner face and outer face, the combination comprising a throat opening formed in said wall and extending between said outer face and said inner face, said throat opening having a generally circular shape at said outerlwall face and diverging toward said inner wall face, said throat opening at said inner wall face being symmetrical with respect to a vertical axis and being asymmetrical relative a horizontal axis, 'said throat opening relative the ho'riz'ontal axis having a greater upward extent than a downward extent, a fluid conduit having a terminus approximately coextensive with the center of said circular throat opening at said outer wall face, a fuel nozzle mounted on the terminus for distributing atomized fuel from said conduit within the boiler, said nozzle including a cap having a convex surface toward the interior of said boiler, said convex surface defining a first fuel opening in the upper quadrant thereof and formed to direct atomized fuel into said boiler to the upper region thereof, said convex surface also defining second and third fuel openings in the side quadrants thereof for directing fuel to the central region of the boiler, said second and third fuel openings having a diameter equal to said first opening, fourth and fifth fuel openings in said convex cap surface in the lower quadrant thereof for directing fluid in a downward direction in said boiler, said fourth and fifth openings having a diameter smaller than said first opening so that fuel issuing from said fourth and fifth opening'has a shorter trajectory than fuel issuing-from said first, second, andthird fuel openings.

2. In a combustion chamber that includes a front wall having an inner face and an outer face and a side wall extending generally normal of said front wall, the combination which comprises a throat opening formed in said front wall and extending between said outer face and said inner face, said throat opening having a generally circular shape at said outer wall face and diverging smoothly toward said inner face at which an inner orifice is defined, said inner orifice having a flattened portion generally parallel to said sidewall, a single nozzle cap mounted centrally of the throat opening, and means for delivering fuel to the nozzle cap, said nozzle cap having a plurality of fuel passages therein which are positioned and oriented so as to distribute fuel in said combustion chamber, said plurality of fuel passage including at least one passage- 2,857,148 10/1958 Niemitz 15s 7x 3,285,315 11/1966 Voorheis 158-4 x FREDERICK L, MATTEVSON, 111., Primary Examiner. E. G. FAVORS, Assistant Examiner.

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