US2931430A - Combination oil and gas burner - Google Patents

Description

Apnl 5, 1960 D. M. MARSHALL 2,931,430

COMBUSTION OIL AND GAS BURNER Filed Feb. 21. 1957 INVENTOR.

David M. Marshall ATTORNEY CoMBINATIoN OIL AND GAS BURNER David M. Marshall, Paclranaek Lake, N.J., assignor to The Babcocli & Wilcox Company, New Yerir, N311, a corporation of New Jersey Application February 21, 1957, Serial No. 641,654 10 Claims. at. 158-11) This invention relates to a fuel burner and more particularly to an improved center-fired gas burner having a novel multiple nozzle or spud arrangement, the instant invention constituting an improvement of a burner arrangement described in a copending application Ser. No. 309,255,-filed September 12, 1952, now Patent 2,826,249.

in order to provide for overall fuel economy in firing .a furnace or combustion chamber of a steam boiler or the like, the combustion chamber or furnace is generally provided with a compact firing arrangement comprising .a fuel burner capable of burning alternate fuels such as gas, oil or pulverized coal which may be fired separately and/or in combination depending upon the amount and availability of the particular kind of fuel. I

Heretofore, in a high pressure center-fired gas burner an annular gas header or ring formed with a plurality of gas ports was utilized in conjunction with an oil burner or pulverized coal burner, the as ring or header circumferentially embracing or otherwise being integrally formed or connected to the burner tube or nozzle of an oil and/or coal burner. However, experience has shown that'seve'ral distinct disadvantages have been encountered in the use of a gas burner so arranged. Due to the high temperatures involved, high temperature stresses are set up in the lher'etofor'e known center-fired gas burner fuel ring which eventually provide the cause for failure of the gas burner and/or its connection to the gas supply which extends .into the vicinity of the high temperature zones. To overcome this troublesome e lfect, it has been necessary to utilize an expensive expansion joint to prevent cracking of the gas burner and/or its supply connections due to the difierential v ex ansion.

Another disadvantage in a gas burner of this type was that the embracing or integrally formed gas ring burner .and associated alternate fuel burner parts constituted a relatively bulky, heavy and unwieldy piece of equipment, thereby rendering it difiicult to permit immediate repair or replacement of the same for cleaning or the like, the weight and bulk thereof becoming particularly aggravated :as the size of the burner is increased.

An object of the instant invention is to provide an improved, center-fired, gas burner which is free from the expansion difiiculties heretofore inherent in center-fired gas burners and which is compact and light in weight and the parts of which are readily rendered replaceable or removable with a minimum of effort whereby the entire burner need not be completely withdrawn from the .furnace port. I I 7 Another object of this invention is to provide an improved gas burner capable of achieving greater flame stability over an increased load range.

More specifically the instant invention burner arrange- :ment comprises an endless or annular gas manifold .removed from the heat of the furnace and arranged 'to be disposed in a spaced parallel plane of. a burner throat extending into a burner port of a furnace wall, the manifold being connected to a source of gas supply under aren't Zfidlflfifi Patented Apr. 5, 1960 rib 2 pressure. Spaced about the gas manifold and connected thereto by readily releasable coupling means are a plurality of individually removable elongated gas spuds which are substantially equal in length and which are extended toward the burner throat, the gas spuds being arranged so as to have their free discharge ends converging toward the central axis of the burner and terminate in a plane substantially parallel to the entrance 'opening of the burner throat.

According to this invention, there is supported adjacent the entrance opening of the burner throat in a plane substantially parallel thereto an impeller means provided with a plurality of apertures for receiving the discharge ends of the gas spuds, the converging discharge ends of the respective spuds extendin'g'therethrough in the direction of the burner throat and terminate in a plane surface having a diameter smaller than that of the impeller.

' The discharge end or nozzle tip of each conduit is provided according to this invention with a face portion having a plurality of gas ports or gas orifices, the face being obliquely disposed relative to an axial plane of the conduit. Accordingly, each conduit is positioned relative to one another so that the face portion thereof discharges gas outwardly therefrom in a stream which diverges outwardly toward the peripheral marginal portion of the burner throat to form a conical spread for admix- 'ture with the air and for combustion of the discharged gaseous fuel in the presence of combustion air delivered to the burner port by the usual air register means.

A feature of the instant invention resides in the provision whereby instant burners may be utilized solely as a gas burner and/or may be utilized in a multiple fuel burner arrangement whereby a fuel other than gas may be {fired as an alternate in combination therewith.

Another feature of this invention resides in the provision 'of 'acente'r-fir'ed gas burner that is compact, light in weight, having a plurality of gas spuds which are individu'ally and readily removable without necessitating complete removal 'of its associated or alternate fuel burning means when utilized in combination therewith.

Still another feature of this invention resides in the provision that the improved gas burner is relatively simple in construction, economical, easily maintained, and positive in operation.

Other features and advantages will be readily apparent when considered in view of the'drawings and specification 'in which: I, 1

Fig.1 is 'a sectiion'al side viewer the improved humor of the instant inventibn, with the detail of the gas burner nozzle shown enlarged; and

Fig. 2 is a furnace end view of the burner.

While the burner of the instant invention may be utilized as a gas burner only, it will be noted that the novel gas burner arrangement herein described is readily in combination with a fluid fuel burning means.

Referring to the drawings, the burner combination 10 is illustrated with. the instant gas burning means 11 novelly arrange in combination with a liquid fuel atomizing 'means12 which may be, for example, of the type shown in US. Patent 2,260,062. Accordingly, the liquid fuel atomizing means 12 is mounted centrally of a circular type burner ll havinga burner throat 13 0 adapted to extend into a port 1'4 formed in a Wall portion 15 of a furnace of a steam generating unit or the like. The burner throat 13 is formed of asuitable refractory material and includes a cylindrical relatively short entrance section 13a which is continuous with a diverging conduit section 1312 leading into the interior of the furnace.- Spaced from the furnace wall 15and extending substantially parallel thereto is an outer casing 16 in which the space formed .therebetween constitutes an air plenum 17 for the flow of combustion airfrom a forced draft fan (not. shown) to the burner port.

An, air entrance means in the form. of a truncated cone 18 is supported. immediately adjacent to the exterior side of the port 14 to direct air into the port. In the illustrated arrangement, the directing cone .18 converges toward the entrance ,of the port the cone-being supported to a structural frame ;worl-', extendin between the furnace wall 15 andthe casing 16. .The combustion air is directedto the clone 18 from. an air register19 having an inner wall 120. and an outer wall ;21, inner wall 20 being connected to. the entrance cone;18. Itwill be noted that between the walls 20 and 21, the. air

. 27 embracing the'burner means 11 and 12 which extend therethrough. The outerends of the two fuel dispersing means 11 and .12. extendthroughthesmall circular cover 28 closing the central opening inthe annular cover plate 25, the circular cover28 forming i an outer closure for the casingor housing 27.

The circular cover 28 supports a central. sleeve member 29 through which there extends a distance. piece 30 forming part of the fuel oil atomizer 12. If desired, the

along the central axial of the burner 10. At the outer end of the distance piece there is connected thereto a liquid fuel supply assembly 31 which connects the fuel ,pipe or oil burner barrel 32 disposed centrally of the distance piece 30 with a source of fuel and oil (not shown).

VOn the inner end of the barrel 32,. there is provided a fuel atomizing head 33which is spaced a short distance from the burner port, the atomizing head 33 .being preferably of the type producing a conical spray of atomized .fgosneso in a plane parallelto andspaced 4 7 source of gas supply under pressure. Spatially disposed and substantially equidistantly spaced about a peripheral portion of the gas manifold, there are provided a plural ity of nipples in communication with the interior of the manifold 39. Connected to the other end of each nipple 40 there is a bend 41 to which an elongated gas conduit or spud 42 is 'releasably connected. As shown the plurality of elongated gas spuds 42 are equi-distantly spaced about the manifold 39 and concentrically disposed about the longitudinal axis of the burner, the spuds 42 extending through spacedopenings 43 in the circular cover 28 and inwardly through the casing 27 toward the burner port 14. To achieve the center-fire gas burner effect, the forward or discharge end 42a of the elongated gas spuds 42 in the illustrated embodiment are coverged toward the central axis of the burner combination 10, the discharge ends 42a terminating from the plane of the burnerport.

According to this invention, the impeller cone 34 is provided witha plurality of equi-distantly spaced apertures 44 spacedinwardly of the base marginal portion for receiving the discharge ends 42a of the gas spuds. It will be noted that the apertures 44 have a. diameter slightly larger than that ofv the gas spuds for loosely receiving the discharge endswhich are projected, beyond the base portions of the impeller and terminate in a spud portion 34a ,of the impeller cone. 30

by the air flowingthrough .andaroundthefimpeller cone 34 produce. a condition. which tends to stabilize a gas flame whengasis fired. If desired, suitable. brackets 45 may be. provided tosupport thegas spuds 42intermedi- .distance piece 30 may be rendered axially, adjustable ate the endsthereoftothe distance piece 30.

With this arrangement, lit willbenoted'. that thegas sup ply. manifold '39. supplying the gas spuds .42 with gas is disposed so. as to be removedfroin the .radiant heat gas conduits 42which extend through theenlarged apertures 44. of the impeller 34 adjacent the-burner port where the .highestQtemperature, occurs, the-individual gas spuds 1 2 are free separately to expand without imposing excessiverstrains on the remainderof the assembly. Sincethe ..spuds 42 and. their discharge tip portions.4212 are the oil having the axis of the conical. spray; co-axial with the entrance cone 18and burner port 14. r

Attached to the inner end of the distancepiece 30 and externally surrounding the atomizer head 33 is an air deflector or. impeller means inthe shape of a truncated cone 34 having the base34o thereofextending outwardly toward the furnace chamber, the impeller cone being concentrically disposed about the longitudinal axis of the burner means 10. The conical surface of the impeller means is provided with a series of equally spaced air openings 35 and corresponding air deflector plates or vanes 36 associated therewith for imparting a whirling motion to the air directed through theimpeller to the central portion of the burnerport. .If.1desired,:an observation port (not shown). may. bepmvided in the. circular cover 28. A1SO'.3.H igniting means 37 is provided. ...Interm,ediate the;ends ofthedistance piece 30 .andimore closelyadjacent the forward end of the'oil burner 12,

The improvedgas burner arrangement 11: of' the instant invention includes an endless orannular gas manifold 39' disposed in a plane substantially parallel to the burner port'14 and spaced therefrom, the manifold 39 being disposed immediately adjacent'the cover'plate 28 'on' theouter side thereof. Means (not shown) are suit- ".ably arranged to connect the manifold to a suitable only portions of the gas .burner arrangement subjected to conditions producing strains and/or corrosive deterioration, they can be readily and simply. removed indeendently of each other by simply breaking the readily releaseable connectionprovided :for .thatpurpose, in the eventthat inspectiomreplacement or repair of the spud elementis required. I r 2 According to this; invention, discharge end 42 a of the elongated gas' spuds'42 isprovided with a. face-portion 45 disposed in a plane oblique relative to thatof an axial plane of the spud. 'The face portion 45 of each conduit is further. provided with a plurality ofaperturesor orifice openings 46 through whichgaslis discharged. .As shown in Figs. land 2, itfwill benoted that the. face portions 45 of eachgas spud are positioned relative to .each other sothatthegas discharged therefrom isdirected outwardly therefromin a conicaldiverging strearn' flowing toward the marginal portion of the burner throat. While the gas spuds 42 maybe provided with anjntegrally formed discharge tip,or nozzle, in 'the illustrated embodiment the gas spud includes a separable tip. or discharge nozzle 42a which maybe. suitably, connected to the barrel portiori4 2b of thegas'sphd'fl by any suitable means such as threaded members. T'However, willbe noted that in eithercase; theelongated gas spuds 42 are formed without interruptions along the length thereof so as to be free of any interfering projections-'which'would tend toobstruct or hinder theremovability -of==thespud from the burner arrangement. If desired a supporting sleeve 47 may be provided for receiving the gas spuds 42.

It has been discovered that with the gas burner arrangement herein described, the instant gas burner can be successfully operated separately or in combination with an alternate fuel burner over a range of gas pressures ranging from .1 inch of mercury to 25 p.s.i., whereby the geometrical arrangement of the burner is such that effective flame stabilization is achieved throughout the entire pressure range. As a result of the effective flame stabilization produced by the instant gas burner arrangement throughout the wide gas pressure range, the operating range or capacity between minimum and maximum peak loadsof a steam generator, boiler or the like adapted to be fired by the instant burner can be greatly increased over that which was heretofore possible.

From the foregoing, it will be noted that the instant burner is relatively simple in construction, light in weight, easily maintained, economical and operatable throughout a relatively wide gas pressure range. Furthermore, the gas burner arrangement is such that eflective mixing of the gas and air is achieved so that sufficient flame stabilization is had throughout the entire operative gas pressure range of the burner, whereby the effective flame stabilizing conditions established throughout the gas pressure range enable the range between minimum and maximum boiler capacities fired by the instant burner to be greatly increased. It is to be further noted that the arrangement of the spuds going through the impeller provides not only a shield from the air flow which helps to get the lower load conditions, but also permits a small amount of air to mix around the spuds to permit early ignition which makes for a more stable burner over its entire range.

While the instant invention has been disclosed with reference to a particular embodiment thereof, it is to be appreciated that the invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.

What is claimed is:

1. An improved gas burner comprising an air register means through which combustion air flows, said register means having an inlet and an outlet end, a vaned air deflector supported therein adjacent said outlet end, and a plurality of gas conduits for conducting fuel gas under pressure, extending through said register and terminating adjacent said outlet end, said conduits having their discharge ends extended through said vaned air deflector whereby the discharge ends thereof are arranged within the periphery of said deflector so as to be shielded from the direct blast of air flowing through said register means, said conduit discharge ends having a plurality of orifices, the orifices of said conduits being disposed to direct streams of gas in a diverging outwardly directed path with respect to the longitudinal axis of the burner.

2. An improved gas burner comprising an air register means through which combustion air flows, said register means having an inlet and an outlet end, a vaned air deflector concentrically disposed therein adjacent said outlet end, and a plurality of gas conduits for conducting fuel gas under pressure, extending through said register and terminating adjacent said outlet end, said conduits having their discharge ends extending longitudinally about the central axis of said burner, the discharge ends of said conduits being extended through said air deflector whereby the discharge ends thereof are concentrically arranged about said axis Within the periphery of said deflector so that said discharge ends of said conduits are shielded from the direct blast of air flowing through said register means and orifices in said discharge ends for ejecting streams of gas in a radially outward direction therefrom relative to the longitudinal axis of said burner.

3. An improved gas burner comprising an air register means through which combustion air flows, said register means having an inlet and an outletend, a vaned air deflector concentrically disposed therein adjacent said outlet end, a manifold means adapted to be connected to a source of fuel gas supply, and a plurality of individually readily removable gas conduits detachably connected to said manifold for conducting fuel gas under pressure, extending through said register and terminating adjacent said outlet end, said conduits having their discharge end extending toward the central axis of said, burner, the discharge ends of said conduits being projected through said air deflector whereby said discharge ends are concentrically arranged about saidaxis within the periphery of said deflector so that said discharge ends of said conduits are shielded from the direct blast of air flowing through said register means, said conduit discharge ends having a plurality of orifices, the orifices of said conduits being disposed to direct streams of gas in a diverging outwardly directed path with respect to the longitudinal axis of the burner.

4. An improved gas burner comprising an air register means through which combustion air flows, said register means having an inlet and an outlet end, a vaned air deflector concentrically disposed therein adjacent said outlet end, and a plurality of gas conduits for conducting fuel gas under pressure, extending through said register and terminating adjacent said outlet end, each conduit including a gas discharge tip portion comprising a face provided with a plurality of orifice openings disposed in a plane oblique to the axial plane of said conduits, said conduits being arranged to extend longitudinally of said burner, the discharge tip portion of said conduits being extended through said air deflector whereby said discharge tip portions are concentrically arranged about said axis within the periphery of said deflector so that said gas discharge tip portions are shielded from the direct blast of air flowing through said register means, the face of each conduit being disposed so that the streams of gas passing through the orifice openings therein flow in a radially outward direction toward the periphery of said outlet end of the register means.

5. An improved gas burner having greater flame stability over a greater load range comprising a burner throat adapted to extend through a burner port in a furnace wall, a gas manifold spaced from said burner throat and adapted to receive fuel from a source of gas supply, an air register means having an inlet and outlet end disposed between said manifold and burner throat for admitting combustion air into said burner throat, means for imparting a swirling movement to said air whereby the major portion of said air tends to form a swirling band of air hugging the peripheral portion of said burner throat, a vaned air deflector spatially disposed within said register adjacent the outlet end thereof, and a plurality of elongated gas nozzles spatially connected about said manifold, said gas nozzles being extended through said register and arranged to extend toward the burner throat so that said nozzles extend through said air deflector so as to be shielded from said combustion air and said nozzles having a plurality of orifices discharging gas streams at the center portion of the burner throat in a radially outward direction toward said band of swirling combustion air.

6. An improved gas burner having greater flame stability over a greater load range comprising a burner throat adapted to extend into a burner port in a furnace wall, an endless gas manifold spaced from said burner throat adapted to receive fuel from a suitable source of gas supply, an air register means disposed between said manifold and burner throat, said register means being axially aligned with said throat for admitting combustion air thereto, means for imparting a swirling movement to said air whereby the major portion of said air tends to form a swirling band of air hugging the peripheral portion of said burner throat, a vaned air deflector spatially disposed adjacent the outlet end of said register and a plurality of manifold, said gas conduits extending longitudinally of said burner toward said burner throat, a nozzlemeans connected to the extended end of each conduit, each of A said nozzle means having a face provided with'a plurality of orifice openings projected through said air deflector to shield the same from the combustion air, saidface being disposed in a plane oblique to an axial plane of its respective conduit whereby gas streams discharged therefrom adjacent the center portion of the burner throat are positively directed radially outward into the major flow of combustion air hugging the peripheral portion of said burner throat to promote thorough mixing of the gas and air.

7. An improved multi-fuel burner comprising an air register through which combustion air flows, said register having an air inlet opening and an axial outlet end means, means for burning an alternate fuel extending through said air register along the central longitudinal axis of said register, a vaned impeller supported by said alternate fuel burning means adjacent said outlet opening, said impeller being concentrically disposed within said register, and a plurality of elongated gas conduits for conducting fuel gas under pressure, extending through said air register, said gas conduits having their discharge end extending toward the central axis of said burner, the extended ends of said conduits being projected through said impeller so that the discharge cndsthereof project therebeyond and concentrically arranged'about said axis within the periphery of said impeller whereby said discharge ends of said gas conduits are shielded from said blast of air flowing through said register, said discharge ends each having a plurality of orifices arranged to eject streams of gas ha radially outward direction toward the periphery of the axial outlet of said air register.

8. An improved combination oil and/or gas burner comprising an airregister through which combustion air 'flows, said register having an air inlet opening and an axial outlet end, an oil atomizing means extending through said air register along the central longitudinal axis'of said register, a vaned impeller supported by said atomizing means adjacent said outlet end, said impeller being concentrically disposed within said register, and a plurality of elongated gas conduits for conducting fuel gas under pressure, extending through said air register, said gas conduits having their discharge end extending through said register, the extending ends of said conduits being projected through said impeller so that the discharge ends thereof extend therebeyond and are concentrically arranged about said axis Within the periphery of said impeller whereby said discharge ends of said gas conduits are shielded from the direct blast of air flowing through said register, each of said discharge ends having a plurality of orifices discharging streams of gas in a radially outward direction to form a diverging conical spray.

9. An improved gas burner comprising an air register means through which combustion 'air flows, said register 'means having an inlet and an outlet end, a vaned air deflector supported therein adjacent said outlet end, and

a plurality of gas conduits extending through said register means and terminating adjacent saidoutlet end, said conduits having their gas discharge ends extended through said air deflector whereby the discharge ends thereof are arranged within the periphery of said'deflector so as to be shielded from the direct blast of air flowing through said register means, and said discharge end of each conduit having orifice means disposed to eject streams of 'gas radially outward with respect to the longitudinal axis of said burner toward the periphery of said axial outlet end of said register means and into the air stream flowing around said air deflector.

"10. An improved combination oil and/or gas burner comprising a circular burner throat adapted to extend into a burner port of a furnace, an air register means having an air inlet opening and an outlet for admitting combustion air to said burner throat, means for imparting a swirling movement to said air whereby the major portion of said air forms a swirling band of air hugging the peripheral portions of said burner throat, an oil atomizing means extending through said air register along the central longitudinal axis of said register, an impeller supported by said atomizing means adjacent said outlet opening, said impeller being concentrically disposed within said register, an endless gas manifold adapted to connect to a source of gas supply, and a plurality of elongated readily removable gas conduits spatially connected about said manifold and extending through said air register, said gas conduits converging toward the central axis' of said burner, a nozzle means connected to the converging end of each conduit, said nozzle means including a face portion disposed in a plane oblique to the axis of the conduit, said face portion having a plurality of discharge orifice openings, the converging end of said conduits being extended through said impeller so that the nozzle means extend therebeyond and concentricaly arranged about said axis within the periphery of said impeller, said nozzle face portions being disposed-to discharge streams of gas outwardly toward the periphery of said circular burner throat and into said swirling band of air.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Dec. 30, 1940

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