US2304294A - Fluid fuel burner - Google Patents

Description

. Dec. 8, 1942. E. 1.. W000 FLUID FUEL BURNER v Filed Feb. 20, 1939 2 Sheets-Shqet 1 VENTOR HWarZJ, 14 004 TORNE ya.

Patented Dec. 8, 1942 2,304,294 FLUID FUEL BURNER Edward L. Wood, Detroit,

Wood Industries, Ina,

ration of Michigan Application February 20, 1939, Serial No.

Mich, aslignor to Gar Detroit, Mich" a coriw- Claims. (01. 158-15) This invention relates tov fluid fuel burners and particularly to a new and novel type of oil burner.

Heretofore in the construction of oil burners it has been customary to blow the air into the combustion chamber by passing it along the outside of the fuel nozzle. That is to say, the fuel nozzle has usually been located within the air duct which supplies the air to the combustion chamber. With such a construction it; has been difflcult to secure a quiet and proper operation of the burner, particularly in furnaces of downdraft construction, for the reason that at the time of starting up the burner there is usually static pressure within the combustion chamber and at all times the pressure at the top of the combustion chamber is different from that at the bottom thereof where the name and gases pass out to the flue opening.

The result of this condition within the combustion chamber is that it requires a considerable amount of pressure to force the air into the combustion chamber in order to start the downdraft circulation. When a sufficient amount of air is thus forced into the combustion chamber past the fuel nozzle, the pressure and velocity is so great that the flame of the-burner is blown back into the combustion chamber a considerable distance and then will travel forward toward the burner, thereby causing a reverberating sound.

On the other hand, if a less amount of air pressure is used, proper movement of the gases in the combustion chamber is not started and, due to the insufficiency of the amount of air, the flame will tend to "hun for additional air and this condition will also cause a noise which is objectionable.

In the present construction, no air is passed in around the fuel nozzle but is admitted to the combustion chamber in advance of the fuel nozzle, and thereby will not in anywise affect the discharge of the fuel from the nozzle. ignition electrodes are also located closely adjacent the discharge end of the nozzle and these are positioned rearwardly of the point of entry of the air and, consequently, are also not in anywise affected by the amount of air pressure used in the furnace.

This improved burner is provided with two air chambers, in the first of which is maintained a predetermined static pressure of air. chamber the air is discharged through a series of ducts arranged at an angle to the axis of the burner into the second air chamber where the air pressure is less than the pressure in the first mentioned chamber and in which the air has a The From this the combustion swirling motion due to its entry from the angularly positioned ducts. From the air chamber having the lesser amount of pressure, 1. e. the second mentioned air chamber, .the air is discharged with swirling motion into the combustion chamber at a point in advance of the fuel nozzle and ignition electrodes. By providing such an arrangement, a sufflcient amount of air under pressure may be admitted to the combustion chamber to properly function in a downdraft furnace against the static pressure therein without in anywise disturbing or upsetting the fuel being discharged from the fuel nozzle and, as a result, the burner operates quietly and efflciently at all times and under all conditions, such as starting cold or starting hot, and will be entirely free of the characteristic or reverberating noise which is present in so many oil burners at the present time.

Therefore, the main objects of this invention are to provide an improved fluid fuel burner which, by the manner of introducing the air into chamber, will result in a quieter and more efficient combustion of the fuel; to provide an improved fluid fuel burner which is readily adjustable to accommodate itself to different requirements; to provide an improved fluid fuel burner in which the quantity of air entering the combustion chamber may be readily varied or ad- Justed to fit varying requirements; to provide an improved fluid fuel burner in which the air entering the combustion chamber is positively directed so as to create an improved flame body within the combustion chamber; and to provide an improved fluid fuel burner in which the operating mechanism is assembled as a unitary structure and such unitary structure is connected to the combustion chamber in such a manner that it may be readily removed for repair, replacement or inspection.

An illustrative embodiment of this invention is shown in the accompanying drawings, in which:

Fig. 1 is a view in side elevation of the improved bumer mounted in a furnace or the like.

Fig. 2 is a view in rear end elevation of the same.

Fig. 3 is a sectional view taken on the line 3-4 of Fig. 2, looking in the direction indicated by the arrows.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3, looking in the direction indicated by the arrows.

Fig. 5 is a view taken along the line 5-5 of Fig. 3, looking in the direction indicated by the arrows, and showing in elevation the air-control valve and the disposition of the air-directing vanes formed thereon.

Fig. 6 is a view of structure similar to that illustrated in Fig. 3, showing a modified form of my invention; and,

Fig. '7 is a sectional view of the structure illustrated in Fig. 6, taken on the line 1-! thereof.

In the construction shown in the drawings, a combustion chamber 40 of cup-shape and having a horizontally disposed axis, is formed of cast refractory material II with a horizontally extending, concentrically disposed, opening in the base thereof. A portion i2 of the opening adjacent the combustion chamber In is cylindrical in shape and the remainder thereof, as shown at I3, is frusto-conical in shape.

The exterior surface of the refractory material Ii within which the combustion chamber i is formed, is substantially cylindrical in shape and is surrounded by a sheet metal housing i4 to which a plurality of radially extending, equidistantly spaced lugs ii are welded, for mounting the burner in a furnace or the like.

The interior of the cylindrical housing I4, spaced inwardly from the rear end thereof, is provided with an annular partition plate It radially disposed, normal to the axis of the bumer, and which is secured in place by being tacked to the inner wall of the housing at a plurality of points by welding or the like. The housing I4 is also provided with two axially spaced rows of circumferentially extending slots I'l disposed in staggered relation, which retard the flow of heat from the forward end of the burner toward the rear end thereof.

The cylindrical and tapered portions of the combustion chamber opening i2l3 are protition wall I6 and which is provided with suitable openings therethrough for attaching bolts 2|.

The bolts 2| also support a plate 23 which is provided with a plurality of eq'ui-angularly spaced, radially disposed, rectangular shaped openings 28 therethrough, the number of which may be varied to suit varying conditions.

The plate 23 is provided with a plurality of rectangular shaped ducts 29 equal in number to the slots 28. The ducts 29 are welded to the plate 23 in registrywith the slots 28 and are disposed at an angle to the axis of the plate so as to cause air passing therethrough to have a swirling motion when discharged therefrom. The plate 23, when secured in position in conjunction with the lining l8, forms an annular air pressure chamber 30, and the angular disposition of the ducts 29 is such that the air is caused to swirl around the annular chamber.

The rear end of the housing i4 is provided with a disc-shaped closure head 3i which is secured in position by screws 32 that pass therethrough and thread into one leg of angle clips 33, the other leg of each of which is welded to 75 the interior surface of the housing l4 closely adjacent the. rear end thereof. The head 3| is axially spaced from the partition plates 23 so as to form an air pressure chamber 80.

The head 3| and the plate 23 are provided with concentrically disposed, axially aligned openings which receiveand siidably support a cylindrical, air valve generally designated 34. The valve 34 comprises an outer cylindrical shell 35 of sheet metal or the like and an inner tightly fitting sleeve 36 of less length than the sleeve 35. A disc-shaped plate or partition wall 31 fits within the rear end of the outer sleeve 35 and abuts against the rear end of the inner sleeve 36 and is held in position by a collar 38 which snugly fits within the rear end of the outer sleeve 35 I8 and and abuts against the partition disc '31, the collar 38 being welded in position.

The front end of the cylindrical valve :4 is positioned co-axially with respect to the combustion chamber opening l2-l3 and closely adjacent thereto for restricting or determining the amount of air passing from the air pressure chamber into the combustion chamber ill. Means are provided for securing the valve 34 in adjusted position and comprise a set screw 64 threaded through one leg of an angle clip 65, the

vided with a sheet metal lining of frusto-conical other leg of which is welded to the cover 3| closely adjacent to the valve 34, so that the inner end of the set screw eng es the outer surface of the valve.

The front end of the outer sleeve 35, adjacent the combustion chamber opening, is provided with a plurality of axially extending vanes 39, which are formed by slitting the metal of the outer sleeve axially inwardly from the end thereof and thencircumferentially for a short distance, the free edge thus formed being bent inwardly toward the axis of the cylindrical valve. The outer end of the inwardly bent portion of each vane is cut away at an angle of approximately 45 so as to provide an end on each vane angularly disposed with respect to the axis of the valve, as shown at 4|. The conformation of the vanes 39 and their angular ends 4| is such as to cause a particular type of swirling action ofthe air which creates a flame in the combustion chamber ID of saucer shape with an axially extending core and which is particularly efiicient. I

The disc 31 is provided with an axially extending concentrically positioned opening for receiving a fuel supply pipe 42, which is frictionally held in position by a pair of diametrically aligned clips 43 and 44, the outer end of each of which abuts against a shoulder formed by striking out the metal of the disc and the inner ends of which engage the outer surface of the fuel supply pipe 42, the clips being held by bolts 45.

The disc 3'! is also provided with two angularly spaced, eccentrically positioned openings for receiving insulated electrode tubes 46 and 41, from the inner ends of which project wires 48 and 49, respectively, in spaced relation, for the passage of an electric spark therebetween for the purpose of ignition. The inner end or nozzle 5| of the fuel supply pipe 42 is steadied in position and held co-axially with respect to the tubular valve 34 by a three-legged clip or spider 50 having equi-angularly spaced, radially projecting legs, the outer ends of which abut against the inner surface of the inner tube 36. The electrode tubes 46 and 41 are held rigidly in position with respect to the fuel nozzle 5! by means of a two piece bracket 52 having a sleeve portion .control valve 34.

which grips the supply pipe 42', and two outwardly projecting sleeve portions which grip the electrode tubes 48 and 41, so that the relative positions of the electrode ends 43 and 43-with respect to the fuel nozzle I will not be changed. 5

thereby.- The electrodes are, disposed out of the path of ejected air and the arc therebetween is not deflected from the fuel as often occurs in burners supplying a flow of air over the nozzle. The disposition of the electrodes in this manner permits a complete control of the air forwardof the burner nozzle without interference by electrodes, brackets and the like obstructions which produce eddy currents of air which disrupt control of the burning fuel.

As shown most clearly in Figs. 1 and 2 of the' drawings, an electric motor 53 is directly connected to a blower, generally designated 56, and to a fuel pump, generally designated 51, all three units being mounted upon a single base member 53. The blower 53 is provided with a discharge duct 59, which communicates with the air pressure chamber 60 and which constitutes the sole support for the operating unit, the duct 53 being secured to the housing i4 by screws or bolts 62. A transformer 63 for supplying'hightension current to the ignition electrodes 48 and 41, is mounted on the top side of the blower 54, but it is to be understood that this transformer may be mounted at any convenient place.-

In the operation of this burner. the air control valve 34 is adjusted axially to regulate the amount of air passing from the chamber 30 into the combustion chamber iii in accordance with the requirements of the particular burner instalv lation and fuel being used. Where oil is used as it) a fuel, the size of the discharge opening through the nozzle 5| determines the amount of fuel at a given pressure which is projected into the combustion chamber Ill, and the amount of air is when the air valve 34 has been adjusted axially for allowing the proper amount of air to pass into the combustion chamber ill, it is secured The axial disposition of the discharge nozzle with respect to the forward end of the air valve may be varied by loosening the bolts which relieve the pressure on the clips 43 and 44.

When the nozzle has been properly positioned with respect to the air valve, these bolts are retightened, thus securely. holding the nozzle in position.

The motor 55 drives the blower 56 and fuel pump 51 for supplying fuel to the discharge noz- 5o ale 5! and maintaining a static pressure of air within the annular air pressure chamber 60. Air from the pressure chamber 60 is discharged through the inclined, angularly disposed ducts 29 into the annular chamber 30 where the air the opening into the combustion chamber iii,

and in so doing, a portion thereof passes through and is directed by the vanes 39 to intensify its swirling action. The vanes 39, with their angled outer ends 4|, cause the air to efliciently atomize the liquid fuel being discharged from the being discharged from the nomle.

- within the sleeve. regulated in. accordance with the amount of fuel. 45

in adjusted position by tightening the set screw tion thereof of saucer shape and an axially dis-,

posed core, the combination of which is extremely efficient.

,By introducing the air into the combustion chamber in advance of the fuel nomle and not in contact therewith, a suflicient volume and pressure may be employed to overcome the static pressure within the combustion chamber, and initiat proper movement and draft in a down draft furnace, without interfering with the fuel rangement results in an extremely satisfactory, quiet and efficient burner. It will'be understood. of course, that it is equally well adapted for updraft furnaces, as well as the downdraft type.

In Figs. 6 and "I I have shown a further form which my invention may assume when the structure above described is to be used upon large types of heating plants. In this connection it was found that when adjusting the sleeve 38 relative to the nozzle II to provide sufl'icient air across the end of the nozzle to support combustion, that too large an opening occurred between the end of the sleeve and the sloping wall l8 which reduced the pressure of the air delivered tothe combustion chamber i0. Since I am interested at all times in retaining the pressure of air ahead of the nozzle sufflcient to overcome the static pressure within the combustion chamber and flue, .I find that by introducing air in a predetermined manner about the nozzle the opening between the end of the sleeve and the sloping wall 18 may be retained while maintaining a desirable pressure. In this arrangement the sleeve 36 is provided with airducts 68 disposed at an angle to the sleeve in the same direction as air is swirled into the passageway an about the outer surface of the sleeve end. A sleeve 69 is provided on the inner wall of the sleeve 33, adjustable by the U-shaped rod ii, for regulating the amount of air thus delivered Where possible, air is cut off from the sleeve 36 through the forward positioning of the sleeve 68 therewithin. Adjustment is preferably made through movement of the sleeve 36 relative to the sloping wall l3. However, when this opening becomes sufliciently 0 large to effect the pressure on the delivered air.

the operation of the sleeve 69 for introducing air 'within the sleeve 36 is then employed for providing the desired amount of air at the nozzle to produce the proper burning of the fuel. The

rotation of the air admitted within the sleeve 33 in the same direction as the air at the head of the nozzle produces the desired control of the flame. The desired pressure is thereby maintained within the combustion chamber which prevents the surging of the pressures within the chamber and furnace that occurred heretofore when such pressure was controlled solely by the draft from the flue.

As a result, when employing my burner I-provide a constant pressure within the combustion chamber, which prevents the surges (at the be ginning of the firing operation) which occurred heretofore when draft alone was depended upon to provide the air for combustion. 1n my arrangement, whether or not a draft is provided by the flue, suflicient air is always provided for complete combus ion of the fuel, and the surge and the accompanying flexing of the metal parts of the furnace which causes noise is thereby eliminated. The pressure in the chamber assures Such an ara constant fiow of swirling air forward of the nozzle which completely controls the resulting flame. The rotation shortens the flame and provides body thereto while producing a complete and uniform mixture of the air and sprayed fuel which is readily ignited by the spark and completely burns within the combustion chamber. The swirling of the air across and forward of the nozzle produces a solid central core which prevents the burning at the nozzle tip and the carbonizing and heating of the nozzle.

When the burner is shut down, the pressure in the chamber is suflicient to continue to provide swirling air across the nozzle after the fuel valve, controlling the supply to the nozzle, is shut oil. This continued supply of air assists in the burning of any remaining fuel passing from the'nozzle end. This retains the nozzle clean and the delivery passage therethrough fully open at all times. The complete uniform burning of the fuel during the shut down period also prevents the surging and pufiing of the flame which often occurred heretofore at the end of a burning cycle resulting in the accumulation of carbon on the nozzle and in the passage therethrough which eventually clogged the opening and produced inefficient operation and eventual shut down.

While the burner is herein illustrated as being a unit attached to a furnace, it is to be understood that the elements thereof may be entirely selfcontained to be attached to any type of furnace which is to be converted to a burner of liquid fuel.

Although but one specific embodiment of this invention has been herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted without departing from the spirit-of this invention, as defined by the following claims.

What is claimed is;

1. In an oil burner, an air chamber, a second air chamber having a wall converging toward an opening, a plate forming a common wall for said chambers, tubes inclined to said plate for con-: ducting air from said first chamber into said second chamber at an angle to the axis of said second chamber and onto the converging wall thereof, an oil delivery nozzle projecting into said second chamber, a shield around said nozzle to prevent the air from contacting therewith, means for supplying air under pressure to said first chamber, and vanes formed on the end of said shield for directing the air passing from the opening in said second chamber forwardly of the nozzle within said shield.

, v 2. In an oil burner, a chamber, means for de- ,livering air within said chamber where it accumulates to build up a pressure, a second chamber having a wall converging toward an opening, a plate separating said chambers, tubes inclined to said plate in said first chamber opening into said second chamber for directing air at an angle to the axis of said second chamber and onto said converging wall, a tubular element extending through said first chamber and spaced from air chamber having a wall converging toward an opening, a common partition for said chambers means for delivering air to said first air chamber to build up a pressure therein, tubes disposed at an angle to said partition through which they extend from said first air chamber into said second air chamber and through which air is delivered from the first said chamber onto the converging wall of said second air chamber with a swirling motion, a cylindrical air valve extending through said first air chamber into said second air chamber in axial alignment with said opening for controlling the fiow of air therethrough, an oil delivery nozzle disposed within said valve, and means for sealing the space between said valve and nozzle to prevent the fiow of air through the valve and about said nozzle.

, 4. In an oil burner, a cylindrical element having a partition to form an air chamber, a hollow frusto-conical element having its large end secured to said partition, angularly disposed tubular elements projecting through said partition and directed toward said frusto-conical element on which the'air delivered from said tubular elements is swirled, a cylindrical valve extending through said air chamber into said element in axial alignment therewith, a partition in said valve, an oil delivery conduit extending through said partition and cylindrical valve, means for supplying air under pressure to said chamber, and vanes on the end of said valve for further swirling the air passing therethrough.

5. In an oil burner, a first air chamber, a second air chamber having an opening, a plate separating said chambers, means for delivering air under pressure to said first air chamber, tubes in said first air chamber extending through said plate and inclined thereto for swirling the air delivered to said second air chamber, a tubular valve extending through said first air chamber into said second air chamber in axial alignment with said opening and controlling the flow of air therethrough, said valve being provided with openings in the part thereof in said first chamber, an oil delivery nozzle disposed within said valve out of the path of fiow of air, and an additional angularly disposed tubular member in said first air chamber projecting from each opening through the wall of said valve for swirling air delivered thereto in the same direction as the air delivered to said second air chamber.

EDWARD L. WOOD.

Images