US2982347A - Fuel burning method and apparatus - Google Patents

Description

May 2, 196] Filed Jan. '7, 1957 gag J. H. KIDWELL ET AL FUEL BURNING METHOD AND APPARATUS FIG. 1

2 Sheets-Sheet 1 INVENTORS John H. Kidwell Gveor e MusaT .Marquand ATTORNEY May 2, 1961 Filed Jan. 7, 1957 J. H. KIDWELL ETAL FUEL BURNING METHOD AND APPARATUS ATTORNEY 2 Sheets-Sheet 2 INVENTORS John H. Kidwell George Musaf United States Patent P 2,982,347 FUEL BURNING METHOD AND APPARATUS John H. Kidwell and George Musat, Canton, Ohio, and Kenneth E. Marquand, Denver, Colo., assignors to The Babcock 8: Wilcox Company, New York, N.Y., a corporation of New Jersey Filed Jan. 7, 1957, Ser. No. 632,884

10 Claims. (Cl. 158-11) This invention relates to a fuel burning apparatus and method and more particularly to an improved fluid fuel burning method and apparatus forbnrning either a liquid or gaseous fuel, separately or in combination.

In relatively large gas and/or liquidfuel fired vapor generating units, it is customary to fire the same by a plurality of burners adaptable for burning either gas or liquid fuel, such as oil, separately or in combination depending on the amount and kind of fuel available. Heretofore, the standard type of burner in use on a large generating unit, whether fired by either oil or gas or in combination, had an individual maximum load capacity of approximately 70 to 90 million B.t.u.s per hour and required various adjustments of air register doors and distance piece to establish desired intermediate burner load conditions between the minimum and maximum burner capacities. These burners further utilized a vaned throat piece or other mechanical means to facilitate mixing of the air with fuel and an impeller means to retain the flame at the burner tip when oil was fired, the impeller being removable in the case of a multiple fuel burner when gas was burned. I

In recent years the trend has been toward larger vapor generating units. As the standard type of fuel burners had limited maximum load capacities due to the inherent construction characteristics thereof, the trend to larger vapor generating units necessitated a steady increase in the number of burners provided for each unit. In some instances, the number of burners on a single unit has reached as high as 32. Such a multiplicity of burners greatly complicated the construction of the boiler walls as well as the windbox. The excessive number of burners further increased the burner air distribution problem and the burner control problem especially when remote burner light-off and individual flame failure protection was required. Furthermore, the constant and periodic replacement of impeller means which constantly burned out further increased the maintenance and operating cost of the impeller type burners heretofore known.

An object of the present invention is to provide an improved fuel burner capable of having a substantiallygreater maximum load capacity so that the number of burners required for the larger present-day vapor generating'units can be kept to a minimum, thereby greatly reducing the difliculties and complexities of the furnace wall construction as well as the operation and control of the burners.

Another object of this invention is to provide animproved fuel burner whereby suflicient combustion air is directed to the central portion of a burner throat so that the performance characteristics of the burner are such that no impeller is necessary and which requires only a single setting of the air doors and distance piece throughout the entire operating range of the burner.

Still another object of the instant invention is to provide a novel method of burning a fluid fuel wherein the retention of the flame adjacent the tip of the burner is accomplished physically by means of a pressure differential within the combustion air stream instead of a mechanical means such as an impeller or the like. 7

Accordingly, the objects, features and advantages of the improved burner of the instant invention are accomplished by a gas and/ or liquid fuel burner having an air register means spatially disposed from a burner or throat opening located in a furnace wall by means of a conduit in which there is located along a longitudinal axis thereof a liquid fuel atomizer means. Disposed in spaced relationship within the conduit and about the atomizing means is an inner sleeve havingan inlet and outlet end, the inlet end thereof extending into the air register portion of the burner to divide the register air into an inner and outer air stream. In addition to dividing the air into a plurality of air streams, the sleeve positively directs a suflicient amount of turbulent air to the central throat portion of the burner. Means are provided in the air register portion for imparting relative velocities to the air streams wherein the inner air stream has imparted thereto a greater spinning or whirling tangential velocity than that of the outer air stream whereby a relatively lower pressure zone is created at the outlet or central portion of the burner tip. Consequently a highly turbulent air mass or stream is positively delivered to the central portion of the burner where it is most desired and thoroughly mixed with the fuel injected therein to promote combustion, the highly turbulent air stream creating the lower pressure zone at the center portion of the burner to establish a flame holding condition thereat.

According to this invention if gas is the intended fuel to be burned, either separately or in combination, a plurality of elongated gas spuds are provided wherein the tip portions thereof are circumferentially spaced adjacent the outlet end of the inner sleeve, the spuds having longitudinally spaced along the axis thereof a plurality of gas orifices in addition to'orifice openings in the tip thereof for directing gas into both the inner and outer air streams to facilitate the mixing of the gas with the air.

In accordance with this invention, the improved method of burning gas or oil either separately or in combination so as to substantially increase the maximum load capacity of a burner is accomplished by supplying combustion air to an air register means wherein it is divided intot'a plurality of air streams, namely an inner and outer air stream having relative velocities, imparting the inner air stream with a whirling velocity greater than that of the outer air stream so as to create a highly turbulent air mass and directing the highly turbulent mass of air to the central portion of an enlarged burner opening. Fuel is then ejected into the air stream adjacent the merging zone of the two air streams whereby the fuel is thoroughly mixed therewith without further aids of any mechanical means, the relative velocities of the air stream being further maintained so as to create relative pressure zones which further enhances mixing as the air streams merge adjacent the fuel injection portion of a burner, the relative velocities of said stream facilitating a flame holding or stabilizing condition of the burner tip.

While the burner of the instant invention may be utilized separately either asa gas burner or an oil burner, the concepts herein stated are equally well adapted for use in a combination gas and/or oil burner wherein the operations, and novel principles and method of mixing the combustion air with either of said fuels or combinations thereof remain substantially the same.

A feature of this invention resides .in the provision whereby the capacity of the instant burner is substantially doubled that of the standard type burner commonly used today, i.e., the improved burner having a maximum capacity of to 183 million B.t.u./hour.

Another feature of this invention resides in the provision whereby twO pieces of control equipment, namely Patented May 2, 191 V the register air door and impeller adjustments, are eliminated.

Still another feature of the invention resides in the provision whereby the air register is removed from the heat radiation effects of the furnace.

A further feature of this invention resides in the provision whereby a suflicient portion of the combustion air is positively directed to the central area of the burner throat to promote combustion thereat and thereby enabling the size of the burners to be efficiently increased.

Another feature of this invention resides in the provision whereby the smaller diameter of the inner sleeve or inner annulus results in an inner air stream having high rate of spinning or angular velocity relative to that of the outer air stream thereby creating a low pressure zone which acts as a pneumatic flame holder at the burner tip.

Still another feature of this invention resides in the provision whereby the burner conduit is substantially equal to the diameter of the burner throat thereby eliminating the requirement for an entrance cone and vanes, impellers or the like to induce a whirling or spinning velocity to an air mass.

Still another feature of the invention resides in the provision whereby the merger of the divided air mass at the burner tip produces an additional turbulence beneficial to promoting combustion.

Other features and advantages will be readily apparent when considered in view of the drawings and accompanying description in which:

Fig. l is an elevation view of the improved gas and oil burner having parts thereof broken away and shown in section.

Fig. 2 is a front end view of the instant burner.

Fig. 3 is an elevation view of a modified burner having parts shown in section.

Fig. 4 is a front end view of the modifier burner having parts thereof shown in section.

In order to meet the capacity and operational demands of a modern steam generating unit or the like whereby the same is desired to be fired by a minimum number of fuel burners and whereby reduce the complexity of the boiler wall construction as well as the operation and control of the burners, there is shown in the drawings in accordance with this invention, an improved burner construction capable of a maximum load capacity which is substantially twice that of the standard 27" circular burner commonly used at the present time. The defined maximum operating capacity of the instant burner is rated at between 145 to 183 million B.t.u.s per hour. while the instant burner construction is equally suitable for independently burning different types of fuel, it is herein illustrated and described for the purposes of description as a combination oil and gas burner which is adaptable for burning either oil or gas separately or in combination.

In the drawings, Figs. 1 and 2, reference numeral is directed to a water-cooled furnace front wall having a circular opening 11 in which the throat 12 of the burner is located. In accordance with this invention, the inner surface of the throat 12 diverges outwardly and toward the furnace side of the wall, the angle of divergement being at least 120 degrees. As it will be hereinafter explained, this wide angle throat reduces fuel impingement thereat and resulting difficulties therefrom at low loads and tends to produce a flow pattern of an orifice having a vena contracta effect which promotes recirculation of the gases and the unburned matter into the main body of the flame.

In the form of the invention illustrated by Figs. 1 and 2, there is spaced from the front wall 10 a casing 13 having an access opening 14 closed by an annular closure plate 15, the space between the front wall 10 and casing 13 forming a windbox or passageway in which combustion air is delivered from an air blower (not shown) to the burner. A circular closure 16 having a laterally extending collar 17 projects through the central opening of the closure plate 15 covering the windbox access opening 14.

As shown, the air register 18 is connected to collar 17 and comprises a pair of spaced annular members 19, 20 forming the end walls thereof. Circumferentially spaced and pivotally mounted between and adjacent the outer periphery of the end Walls 19, 26 of the air register are a plurality of register doors 21 which are adapted to be pivoted between open and closed positions and which in the open position enables the air register to be in communication with the interior portion of the windbox. If desired, the air doors 21 may be suitably geared, linked or otherwise connected together so as to be responsive to an operating means which may be either manually or automatically controlled to simultaneously operate the doors in response to the actuation of the operating means. In the illustrated form of the invention, the operating means comprises a manually operated means 22. Thus, it will be noted that in the event that it is necessary to shut down the burner, all the doors 21 may be simultaneously moved to closed position by operation of means 22 to cut off the air supply to the burner. It will be noted also that the air doors 21 in addition to admitting air into the the air register when in open position also imparts to the air entering thereinto a whirling, spinning or angular velocity.

According to this invention, the air register 13 is laterally spaced from the burner throat 12 by a burner tube or conduit 23, the latter being substantially equal in diameter to the throat opening and disposed adjacent thereto, thereby eliminating the need of an entrance cone. Consequently, it will be noted that the register 18 is set back in the windbox and remote from the radiation effect of the furnace.

Located centrally of the air register 18 and extending along the longitudinal axis of the burner conduit 23, there is disposed a suitable oil atomizing means 24 having its rear portion supported in the circular closure 16 and its forward end supported by a suitable bracket or spider 25.

According to this invention, there is spatially disposed within the burner conduit 23 and about the fuel atomizing means 24 an inner sleeve member or annulus 26 having an inlet end 26A, and an outlet end 26B. As shown in Figure 1, the inlet end 26A of the sleeve member 26 extends into the air register 18 and is flared outwardly or hell shaped to divide the register air into an inner air mass or stream and an outer air mass or stream. Bracket or struts 25A and 25B support the inner sleeve in spatial relationship within burner conduit 23.

In the form of the invention shown in Figs. 1 and 2, it is to be noted that the air entering the air register has imparted thereto an angular velocity through doors 21 which is retained in the divided air streams, although it has been discovered that the angular velocity of the outer air stream is substantially reduced adjacent the discharge end of the burner. Since the diameter of the inner annulus or sleeve member 26 is smaller than that of the burner conduit 23, the inner core of air or stream flowing through the sleeve has imparted thereto a relatively greater angular velocity than that of the outer air stream. As a result of the increased angular velocity of the inner core, the central portion or mass of air is rendered highly turbulent, the turbulent mass of air being directed by means of the sleeve to the center portion of the burner throat. Since a sufficient amount of turbulent air can be positively directed to the central portion of a burner in the manner described, the size of the burner may be efficiently increased. A burner having a throat opening with a 36 inch diameter proved successful. As a result of the diiferential of velocities established between the inner and outer air streams it will be noted that a lower pressure zone is created at the central portion of the burner. It has been discovered that the reduced pressure zone at the center of the burner,

1 together with the whirling effect of the inner air stream established a flame holding condition at the burner tip, thereby eliminating the need for an impeller.

In order that the burner of Figs. 1 and 2 may also operate on gas, a plurality of gas spuds 27 are circumferentially spaced around and adjacent to the discharge end 2612 of the inner sleeve member 26. As shown in Figs. 1, it has been discovered that the most effective arrangement of the gas spuds 27 is to have the tip portion 27A thereof project through the burner conduit 23 in the vicinity of the outlet end 26B of the inner sleeve as shown. In this manner, the spuds 27 do not interfere with the air flow through the burner.

In order to facilitate the removability or replacement of thegas spuds, it will be noted that the spuds com-.

prise an elongate tubular member 27B having an arcuate configuration of a suflicient radius so that the same can be readily inserted through an opening in the circular closure plate 15, the arcua-te configuration of the spud 27 being such that the same clearsthe register portion 18 of the burner as it is inserted through the, opening 28 in the burner conduit 26. In the form shown, twelve spuds 27 are equidistantly spaced around the discharge end 263 of the burner tube 26, the end portions thereof being connected to a gas ring manifold 29' adjacent the front wall of the burner and the manifold 29' being connected to a source of gas supply (not shown) by means of a supply pipe 29A.

In accordance with this invention, it will be noted that the tip 27A of each gas spud is provided with a plurality of spaced gas orifices 30' extending along the longitudinal:

axis thereof in addition to the plurality of gas orifice openings 31 located in the tip portion of the spud. The

1 gas orifices 30 extending along the longitudinal axis of the spudare positioned so as to direct a gas outwardly therefrom on both sides thereof in a direction substantially 90 transverse to that of air stream flow. With able a suflicient amount of turbulent air at the central portion of the burner so asto promote thorough mixing of thefuel'with the air necessary for proper combustion.

Further, it is to be noted that the relative velocitiesim- .jflp'arted to the airstream create relative pressure zones with it he'lower pressure zone formed at the center portion.

of the burner and functions as a pneumatic flame holder.

"The burner is alsoprovided'with an igniter means 32 and usual inspection door 33.

-The,burner 'is lighted by means of the igniter 32 V,

6 angled throat opening 51 located in a furnace wall 52 as 'hereinbefore described. A burner conduit 53 extends forwardly of the burner opening, having an oil atomizing means 54 being located along the central axis -'thereof. Axially and spatially disposed within the burner conduit 53 and about the atomizer means 54, there is provided an inner sleeve or annulus member 55 having an inlet end 55A extending beyond the inlet end 53A of the burner conduit 53. As shown in Figs. 3 and 4,

the inlet end 55A of the inner sleeve 55 is provided with a pair of spaced laterally extending flanges 55B, 55D having horizontally disposed th erebetween and circumferentially spaced thereabout a plurality of vanes 56.

' A' casing'member 57' spatially surrounds the burnerconduit 53, the casing 57 having a front wall 57A abutting the inlet end 55A of the inner sleeve. Thus an annular air chamber 58 is formed between the casing 57 and conduit 53 which isin communication with an air duct 59 connected to a header or source of combustion air (not shown),

As indicated by the arrows A, the combustion air enters the annular air chamber 58 and is directed to the forwardor air register portion 58A of thecasing wherein the mass of combustion air is divided into an outer air stream having generally an axial velocity and an inner air stream flowing through the inner sleeve, member, the latter stream having imparted thereto by the vanes 56 a highly turbulent angular and helical velocity.

Consequently as hereinbefore described, the relative velocities of the air stream creates a differential pressure zone within the burner to enhance the mixing of the air and fuel as well as to create a flame holding condition at the tip of the burner.

As shown in Fig. 3 damper means 60 are provided to-cut off the air supply to the'burners, the damper means 60 being optionally disposed at either in the-inlet air duct as shown or in the air chamber 58 adjacent the air register portion 58A as shown in the phantom line.-

With this arrangement, it will be noted that the necessity of a large windbox on a multiple burner generating unit can be eliminated and that with the modified burnor of Figs. 3 and 4 of a multiple'arrangement, each burner can be supplied through an individual inlet. This "arrangement permits individual adjustment of the burner control dampers to compensatefor unequal air distribution if such is necessary.

In the event that gasis to be fired, the modified burneris provided with-a plurality of gas spuds 61 circumferentially spaced about outlet end B of the inner sleeve 55 in the manner hereinbefore described, the gas spuds being connected to a-sui-table manifold 62. 'In all other respects, the operation and function of the modified burner is substantially the same as the'burner illustrated in Figs. 1 and 2.

The method herein employed by which the maximum .capacity of to 183 million B.t.u. is attainable by the burner construction herein shown and described com prise the steps of introducing a supply of combustionair the usual manner whether fired vongas or oil with the .air

doors wide open. With the burner in operation, the

firing rateflcan be varied overa '10 to 1 range from 1,090 to IlL OOG lbs. of oil without the requirement or any furthe'r adjustment of the door 21 or the distance .l piece of the fuel atomizing means The flamehas a short, snappy well-defined patterniwith excellent sta j'bility'andfcompleie"combustion is h'ad'over'ijthe entire; firing range within the' "standardlimitation of excess air. i Furthergthe wide angle, burner throat discharge results U ina'p'ositive flame-pattern in the main flamejbody ands "alisoin the outer "frontal zohe where'lthe fiame is recircuj "lated to the rootofthe initial combustion zone,

"ofth'e instantinvention are such that theiimpeller 'and inherentdisadvantages ther'edf are eliminated; Also into an air registry portion 58A of a burner and divid ing the same into a plurality of air streams namely aninner'a1rstream and' an outer air stream and imparting. to

the air streams arelativevelocity-. Accordingly, the in-- t ner air streamv has imparted theretopahighly 'turbulent 7' tangential velocity greater than that of the outer. air 7 stream the former being positively directed to the central portion of the burnerwhere itis needed most; This f v condition, 'it will-the noted," enhances 'thorough'mixing'ofj 1 "fthe air and fuel whichisinjected'into theair streams. I i

- For the foregoing, it will be'noted that the novel burn er; constructionland method-ofburning enables the size v I o f the burner: to be efiiciently-incr eased whereby maxi- 1 .mum capacity'the'reof is, greatly increased.. Runthe that i i operating charaeterietics ofthe' illustrated embodi-i the operation and'control of the improved burners of the instant invention are greatly simplified in that no adjustment of the air doors or distance piece is required throughout the entire operating range of the burner.

While the instant invention has been disclosed as to particular embodiments 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. For use with a furnace wall having a burner port therein, an improved gaseous fuel burner comprising an air register for receiving combustionair at superatrnospheric pressure, said air register having a central axis, an air inlet, and an axial annular air outlet, adapted to be concentrically disposed with respect to a burner port, a burner conduit having a longitudinal axis adapted to connect said annular air outlet with the burner port and to remotely position said air register from the radiation elfects of the furnace, said burner conduit having a discharge end portion adapted to be disposed immediately adjacent the port, an inner sleeve concentrically disposed within said conduit in spaced relationship therewith, said sleeve having an inlet end opening to said air register for dividing the air leaving said register into an inner air stream and an outer air stream, and said sleeve having an outlet end spaced along the longitudinal axis of said conduit inwardly of the discharge end of said burner conduit, means for imparting a turbulent velocity to each of said air streams whereby said streams create relative pressure zones within said conduit, and means positioned for injecting streams of gaseous fuel directly into and transversely of each of said air streams within said conduit adjacent theoutlet end of said sleeve so that the relative turbulence and velocity of said air streams coact to enable the gaseous fuel to be thoroughly mixed with said air to enhance combustion, and the relative pressure zones established adjacent the outlet end of said sleeve and the discharge end of said burner conduit creating a flame holding condition thereat.

2. For use with a furnace wall having a burner port therein, an improved gaseous fuel burner comprising an air register for receiving combustion air at superatmospheric pressure-said air register having a central axis, an air inlet, and an axial annular air outlet aadpted to be concentrically disposed with respect to a burner port, a burner conduit having a longitudinal axis adapted to connect said annular air outlet with the burner port and to remotely position said air register from the radiation effects of the furnace, said burner conduit having a discharge end portion adapted to be disposed immediately adjacent the port, said discharge end portion having a diameter adapted to be substantially equal to the diameter of the burner port, an inner sleeve concentrically disposed within said conduit in spaced relationship therewith, said sleeve having an inlet end extending into said air register to permit said sleeve to dividethe air in said register into an inner air stream and an outer air stream, and said sleeve having an outlet end spaced along the longitudinal axis of said conduit inwardly of the discharge end of said burner conduit, means for imparting a turbulent velocity to reach of said air streams'whereby said streams create relative pressure zones withitn said conduit and gas spuds having opposed, parallel, longitudinally extending wall portions, and a row of spaced orifices disposed in each of said wall portions, said spuds being positioned so that the gas streams discharging from said orifices are ejected directly into and transversely of each of 'said air streams within said conduit adjacentthe outlet end of said sleeve so that the relative turbulence and velocity of said air streams co-act to enable the gaseous fuel to be thoroughly mixed with said air to enhance combustion, and the relative pressure zones established adjacent the outlet end of said sleeve and the discharge end of said burner conduit creating a flame holding condition thereat.

3. The invention as defined in claim 2, wherein each of said spuds includes a tubular member readily detachable from said manifold, each of said members having a tip end, said tip end having an oblique face relative to an axial plane of said tubular member, said face having a plurality of discharge orifices therein, and said row of aligned spaced orifices positioned on opposite sides of said spuds being disposed adjacent the tip end.

4. For use with a furnace wall having a burner port therein, an improved impellerless gaseous fuel burner comprising an air register for receiving combustion air at superatmospheric pressure, said air register having a central axis, an air inlet, means for imparting a whirling motion to the air upon entering said air inlet, and an axial annular air outlet adapted to be concentrically disposed with respect to the burner port, a cylindrical burner conduit having a longitudinal axis adapted to connect said annular air outlet with the burner port and to v remotely position said air register from the radiation effects of the furnace, said burner conduit having a smooth inner surface and a discharge end portion adapted to be disposed immediately adjacent the port, said discharge end portion having a diameter adapted to be substantially equal to the diameter of the burner port, an inner sleeve having a smooth inner surface concentrically disposed within said conduit in spaced relationship therewith, said sleeve having an inlet end extending into said air register to divide the whirling air in said register into a whirling inner air stream and a whirling outer air stream, and said sleeve having an outlet end spaced along the longitudinal axis of said conduit inwardly of the discharge end of said burner conduit and the whirling motion imparted to each of said air streams creating a relative pressure zone within said conduit, and means positioned for injecting streams of gaseous fuel directly into and transversely of each of said air streams within said conduit adjacent the outlet end of said sleeve so that the relative whirling movement of said air streams co-act to enable the gaseous fuel to be thoroughly mixed with said air for enhancing combustion, and the relative pressure zones established adjacent the outlet end of said sleeve and the discharge end of said burner conduit creating a flame holding condition thereat.

5. For use with a furnace wall having a burner port therein, an improved impellerless gaseous fuel burner comprising an air register for receiving combustion air at superatmospheric pressure, said air register having a central axis, an air inlet, and an axial annular air outlet adapted to be concentrically disposed with respect to the burner port, a cylindrical burner conduit having a longitudinal axis adapted to connect said annular air outlet with the burner port and to remotely space said air register from the radiation efiects of the furnace, said burner conduit having a smooth inner surface and a discharge end portion adapted to be disposed immediately adjacent the port, said discharge end portion having a diameter adapted to be substantially equal to the diameter of the burner port, an inner sleeve having a smooth inner surface concentrically disposed within said conduit in spaced relationshisp therewith, said sleeve having an inlet end extending into said air register to divide the air in said register into an inner air stream and an outer air stream, and said'sleeve having an outlet end spaced along the longitudinal axis of said conduit inwardly of the discharge end of said burner conduit, adjustable" air register'doors to control the flow of air through said air register inlet, said air doors imparting a whirling movement to each in said conduit, and means positioned for injecting streams of gaseous fuel directly into and transversely of each of said air streams within said conduit adjacent the outlet end of said sleeve, said fuel injecting means including a gas manifold-spaced from the outer side of said air register, and a plurality of circumferentially spaced elongated tubular members detachably connected to said manifold, each of said members extending from said manifold to a point adjacent the outlet end of said inner sleeve, a tip connected to each of said members, said tips each having an oblique face relative to an axial plane thereof, said face having a plurality of discharge furnace having a furnace wall with a burner opening therein, a multiple fuel burner capable of a maximum load capacity of approximately 183 million B.t.us per hour comprising an air register for receiving the combustion air, said air register having a central axis and an annular outlet disposed about said axis, a cylindrical conduit having a longitudinal axis and a smooth inner surface connected to said annular outlet for remotely spacing said register from a burner port and the radiation effects of the furnace, said conduit having a discharge end portion adapted to be disposed immediately adjacent a burner port, said discharge end having a diameter adapted to be substantially equal to that of the port, an oil atomizing means located along the central axis of the burner, an inner cylindrical sleeve having an inlet end and an outlet end concentrically disposed within said conduit and about said atomizing means in spaced relationship therewith, said inlet end of the sleeve extending into the air register to divide the air in said register into an inner air stream and an outer air stream, and said outlet end 'of said sleeve being spaced along the longitudinal axis of said conduit inwardly of the discharge end thereof, a gas burner, said gas burner including a gas manifold, a plurality of individual gas spuds detachably connected to said manifold, said spuds having their tip ends terminating in a circle circumferentially spaced from the outlet end of said sleeve and within the. outer end of said conduit, said spuds having a plurality of orifices positioned to discharge streams of gaseous fuels directly into and transversely of each of'the said air streams, means imparting relative velocities to each of said air streams so that the division of combustion air by said sleeve facilitates thorough mixing of oil and/or gas with said air and creates a flame holding condition adjacent the discharge end of the burner conduit whether the said oil or gas is fired separately or in combination.

7. An improved gaseous fuel burner comprising an air register for receiving combustion air at superatmospheric pressure, said air register having a central axis, an air inlet, and an annular air outlet concentrically disposed with respectto said central axis, a burner conduit having a longitudinal axis coincidental with the central axis of said air register, said conduit being adapted for connecting said air register annular outlet with a burner port and for remotely positioning said air register from the radiation effects of a furnace, said burner conduit having a discharge end portion provided with a diameter adapted to be substantially equal to the burner port diameter and adapted to be disposed adjacent a burner port, an inner sleeve concentrically disposed within said conduit in spaced relationship therewith, said sleeve having an inlet end extending into said air register and an outlet end spaced inwardly of the discharge end of said burner conduit along the longitudinal axis thereof, whereby said inlet end of said sleeve divides the air in said air register into an outer air stream and an inner air stream so that the outer air stream is discharged from said air register through said annular outlet and said inner air stream is discharged from said register through said sleeve, means for imparting a turbulent velocity to each of said air streams for creating relative pressure zones adjacent the discharge end of said conduit, and means positioned for injecting streams of gaseous fuel directly into and transversely of each of said air streams within said conduit adjacent the outlet end of said sleeve so that the relative turbulence and velocity of said air streams co-act to enable the gaseous fuel to be thoroughly mixed with said air to enhance combustion, and the relative pressure zones established adjacent the respective ends of said,

rotating air into an inner and an outer rotating air stream having relative angular velocities to create a pair of relative pressure zones, positivelyv directing the inner rotating air stream toward the central portion of the burner, and injecting streams of gaseous fuel directly into and transversely of each of said rotating air streams whereby the rotating air streams provide for thorough mixing of the fuel and air to enhance combustion and the relative pressure zones created thereby establishing a flame holding condition at the burner.

'9. The invention asdefined in claim 1, wherein said means for imparting a turbulent velocity to' said air streams include means for imparting a linear velocity to said outer air stream, and vane means disposed within said air register immediately adjacent the inlet end of said sleeve to induce a whirling motion to the inner airr stream flowing through said sleeve.

10. The invention as defined in claim 9, wherein said vane means include a plurality of circumferentially spaced blades defining therebetween a plurality of circumferentially spaced substantially tangential air inlets opening to the inlet end of said inner sleeve.

References Cited inthe file of this patent UNITED STATES PATENTS 1,136,849 Tucker Apr. 20, 1915 1,687,390 Ritter Oct. 9, 1928 1,801,431 Irish Apr. 21, 1931 1,907,838 Leask May 9, 1933 1,966,524 Schenck Apr. 13, 1934 1,986,796 Florez Jan. 8, 1935 2,111,908 Andrews Mar. 22,1938 2,259,818 Henriksen ,Oct.21, 1941 2,274,818 Zink Mar. 3, 1942 2,359,049 Nagel Sept. 26, 1944 2,368,490 Patterson Ian. 30, 1945 2,439,609 Mittendorf Apr. 13, 1948 2,485,656 Raskin Oct. 25, 1949 2,515,843 Nuyl July 18, 1950 2,826,249

Poole Mar. 11, 1958

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