US2829708A - Gaseous fuel burner for curved combustion chambers - Google Patents

Description

April 1958 N. 5. CAMPBELL ET AL 2,829,708

GASEOUS FUEL. BURNER FOR CURVED COMBUSTION CHAMBERS Filed Dec. 27, 1955 I INVENTOR (Kari-[e5 J. Fezb/zeldsrfer Md 4 cum D5622 BY ATTORNEY United States Patent GASEOUS FUEL BURNER FOR CURVED COMBUSTION CHAMBERS Ned G. Campbell and Charles A. Reichelderfer, Columbus, Ohio, assignors to Norman Products Company, Columbus, Ohio, a corporation of Ohio Application December 27, 1955, Serial No. 555,462

3 Claims. (Cl. 158-7) This invention relates to fuel burners and, more particularly, to burners of the type utilizing admixed air and a hydrocarbon gas as fuel, and whereby such fuel when projected from the burner is utilized for active combustion in confined, ring-like, heat-transferring chambers of ceiling mounted, circular, unit heaters.

Examples of prior circular unit heaters are found in Patent No. 2,519,496, granted August 22, 1950 to E. A. Norman, Jr. and Patent No. 2,697,428, granted December 21, 1954 to E. A. Norman, Jr., et al. One of the problems encountered in the operation of these heaters has been the difficulty presented in avoiding localized overheating of the walls of fuel combustion chambers or zones of heat-exchanging apparatus, and consequently a lack of temperature uniformity in the overall operation of such apparatus. Localized exchanger wall overheating is primarily attributable to direct burner flame impingement on such walls and, also, to the failure of such exchangers to provide equalized burner gas flow, particularly in constructions in which the burner gases flow takes place in multiple or parallel streams through a plurality of passages and is apt to be channeled or largely confined in one or more of such passages with proportionately diminished flow in others.

' Accordingly, it is a primary object of the present invention to provide an improved gaseous fuel burner for use in association with a heat-exchanger embodying a combustion chamber formed by arcuate inner and outer walls, and wherein the burner proper is formed with one or more orifice-containing segmental walls for the projection of jetted gaseous fuel streams into the combustion chamber present between said inner and outer walls in producing high temperature active fuel combustion on the part thereof, the segmental wall of the burner and the arrangement of the orifices therein serving to cause the jetted streams to converge toward a theoretical focal line spaced a maximum linear distance from the burner wall as the physical limits of the combustion chamber will permit, such focused projection of the combustible mixture precluding undue or premature flame impingement on the walls of the combustion chamber and the avoidance of localized overheating and early deterioration thereof.

The burner disclosed in this application comprises an improvement over the burner disclosed in copending application Serial No. 374,544 filed August 17, 1953.

For a further understanding of the invention, reference may be had to the following description and the accompanying drawing, wherein certain preferred embodiments of the burner forming the present invention are illustrated and wherein:

Fig. 1 is a horizontal sectional view taken through a ring-like combustion chamber of a heat exchanger of a unit heater and disclosing a burner, formed in accordance with the present invention, mounted therein;

Fig. 2 is an enlarged vertical transverse sectional view taken substantially on the plane indicated by the line 2-2 of Fig. 1;

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Fig. 3 is a detail perspective view of the burner when removed from the combustion chamber of a heat exchanger and disclosing its dual, segmental, orificed walls;

Fig. 4 is a similar view disclosing a modified form of the burner in which but a single orifice-containing wall is utilized.

Referring more particularly to the drawings, the numeral 5 designates the ring-like combustion and burner gas circulating chamber of a heat exchanger, such as that shown in the copending application of ourselves and Edward A. Norman, Jr., Serial No. 555,514, filed Dec. 27, 1955, entitled Forced-Draft Unit Heater Having Outside Combustion Air Source, and employed in room heaters adapted for overhead installation. As shown, the chamber is defined by inner and outer, transversely spaced, relatively concentric side walls 6 and 7, respectively, and substantially flat, horizontally disposed, top and bottom walls 8 and 9, there being an outlet 10 formed in the top wall 8 at one side of the heat-exchanger, for the discharge of burner gases from the combustion chamber, the outlet leading to a suitable point of discharge for such gases, preferably one disposed exteriorly of a building in which the apparatus is positioned for use.

Mounted in the combustion chamber, on the opposite side thereof with respectto the outlet 10, is a hydrocarbon gas buruer 11. In the form illustrated, the burner 11 is formed to include an internal mixing chamber 12 which is in open communication with a fuel-supply pipe 13. Hydrocarbon fuel gas admixed with pr1mary combustion air is admitted into the burner chamber 12 by way of pipe 13 and issues from the burner in the form of relatively convergent jets or streams through orifices 14 fonned in a pair of spaced, oppositely facing, arcuate or segmental walls 15. The axes of the orifices of each wall 14 are disposed to converge at a vertical line X coincident to the inner surface of the outer wall 7 of the combustion chamber. The burner chamber is further defined by flat, horizontally extending top and bottom walls 16 and 17, respectively, and by a peripherally depending supporting flange 18 which is adapted to be positioned on the bottom 9 of the burner chamber.

In the operation of the burner mechanism disclosed, a primary air and fuel mixture is admitted into the chamber 12 of the burner casing under pressures providing for the positive advance of the mixture so introduced from said chamber and passage thereof through the ports or orifices 14 of the curved walls 15 of the burner casing. Due to the use of the curved walls 15 and the arrangement of the axes of the orifices 14 therein, jets of the primary air and fuel mixture are projected outwardly into the combustion chamber 5 of the heat exchanger in tapering or focused streams toward the focal lines X. The primary air and fuel mixture comprising said jets is then admixed with secondary volumes of air entering the chamber 5 through an opening 19 therein and through which the pipe 13 passes. The two oppositely directed individually converging streams Y of gas and air are projected into the combustion chamber 5 from the opposite faces 15 of the burner in a manner causing each stream to travel tangentially of the inner wall 6 and thereby miss direct contact with said inner annular wall of the chamber 5, said streams avoiding direct impingement of the outer wall 7 until reaching the focal lines X. In this manner, when the fuel-air mixture is ignited at the burner, by means of an appropriate pilot burner, not shown, the flame propagation patterns follow generally the path of the fuel-air mixture streams Y, but, of course, the flame patterns will be relatively wider than the theoretical streams Y, due to expansion of gases upon combustion, and each flame pattern will generally terminate in an apex short of the theoretical focal lines X, due to complete combustion of the fuel-air mixture prior to its arrival at such focal lines. The arrangement provides for efiicient fuel combustion and avoidance of injury and deterioration of combustion chamber walls through concentrated flame contact therewith,

In Fig. 4 the burner 11a is modified for use in a segmental, type of combustion chamber, rather'than the full ring type of Fig. 1. Therefore, the burner 11a is merely provided with a single orificed wall 15a in lieu of the dual walls 15, above defined.

Various other modifications will be apparent to those skilled in the art and, therefore, the constructions illustrated and described in detail herein are to be considered as examples and not in a limiting sense, except as the context of the following claims imposes the same.

We claim: 1

1. The combination with a heat-exchanger having a horizontally extending annular combustion chamber defined by relatively concentrically disposed. inner and outer circular side Walls joined by top and bottom walls of a gaseous fuel burner positioned directly in said chamber between said walls, said burner embodying a casing formed with an internal primary air and fuel mixture-receiving chamber defined on the sides thereof by a pair of arcuate side walls having concave outer surfaces facing toward opposite sides of said combustion chamber, said arcuate walls being formed with a multiplicity of relatively closely spaced orifices for the discharge of a primary air and fuel mixture from the chamber of 'said burner and into the opposite sides of said heat-exchanger combustion chamber, the axes of the orifices of each of said arcuate side walls being focused toward a common vertical center line along the outer side wall of said combustion chamber and being arranged to project relatively convergent streams of primary air and fuel mixture generally tangentially of and beyond the periphery of the inner wall of said combustion chamber.

2. The combination with a heat-exchanger having a horizontally extending annular combustion chamber defined by relatively concentrically disposed inner and outer circularly curved side walls joined by top and bottom walls of a gaseous fuel burner positioned directly in said chamber between said walls, said burner embodying a casing formed with an internal primary air and fuel mixture-receiving chamber defined on at least one side thereof by an arcuate side wall having a concave outer surface facing toward one side of said combustion chamber, said arcuate wall being formed with a multiplicity of relatively closely spaced orifices for the discharge of a primary air and fuel mixture from the chamber of said burner into a side of said heat-exchanger combustion chamber, the axes of the orifices of said arcuate side wall being focused toward a common vertical center line along the outer curved side wall of said combustion chamber and being arranged to project a tapering stream of primary air and fuel mixture generally tangentially of and beyond the periphery of the inner wall of said combustion chamber.

3. The combination with a heat exchanger having a horizontally extending combustion chamber defined by relatively concentrically disposed inner and outer arcuate side walls joined by top and bottom walls of a gaseous fuel burner positioned within said combustion chamber between the side walls thereof and formed with an internal fuel-air mixture-receiving chamber, said burner having on each side thereof an inwardly concave wallforming structure providing a plurality of relatively spaced openings disposed in free communication with the fuel-air mixture-receiving chamber of said burner and through which a fuel-air mixture received in the chamber of said burner may pass outwardly to each side of said burner into the combustion chamber of said heat exchanger, the central axes of the openings provided by each of the wall-forming structures of said burner being focused toward a vertical focal line along the outer side wall of said combustion chamber at a point thereon substantially remote from said burner and being arranged to project relatively convergent streams of fuel-air mixture generally tangentially of and beyond an adjacent peripheral portion of the inner wall of said combustion chamber.

References Cited in the file of this patent UNITED STATES PATENTS 824,972 Borne July 3, 1906 948,133 Coyle Feb. 1, 1910 2,311,994 Parker Feb. 23, 1943 2,435,638 Shorter Feb. 10, 1948 2,486,018 Furkert Oct. 25,1949

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