US1996336A - Burner for liquid fuel - Google Patents

Description

April 2, 1935. H. JUNKERS 1,996,336

BURNER FOR LIQUID FUEL Filed Jan. 2,A 1932 www Patented Apr. 2,A 1935I UNITEDIfsgTArES Lacasse l QWn'URNER roRILIQUn'FEL Hugo Junkers, Dessau, Germany, assignor to firm: Junkers & Co., G.v m. b.fH., Dessau,` Germany mmm mm2 193.2, Serial No. 584,478

zcl'aims. (ci. 15s-117)' My invention relates -.to burners for liquid fuel and more particularly `toburners having a rotary atomizer from-'the upper edge of which the fuel is projected by centrifugal action into flow- 5 ing air so that avsuitable mixture of air and fuel is obtained.I n V Burners of this type as designed'rheretofore present the following drawbacks:

have been suggested, increase considerably the Ep'ow'er input of the burner. It has been suggested to eliminate stufng boxes by supplying the fuel through the hollow shaft of the motor by which the atomizer is rotated, but this expedient` increases thev initial vcost of the motor. Secondly,

the operation of burners as designed heretofore. is so difficult as to render them almost unsuity ablevfor household purposes.

Itis an object of my invention to eliminate Athese drawbacks. l

" To this end I provide a tubular extension on theatomizer which projects below the level of` the liquid in the fuel reservoir so that the fuel is fed to the atomizer, preferably to a circular edge, by centrifugal action and Without any Ameans for conveying it.

I further provide means, such as a Marotte flask, for maintaining the .fuel in thereservoir substantially at the same level, and by this means, .in combination with the centrifugal feeding means, dispense with extra means or conveying the fuel, including a supply pipe. The tubular tension the fuel rises along the'inner wall at a denite and not excessive rate only if the at- 50 provided in the mixingtube for admitting secondary airto the :mixing tubebeyond the at.- omization zone. r

I further providea motor for imparting rotation to the atomizer, normally an electricmotor,y 55 having a vertical shaft and arranged below the extension of the atomizer may be cylindrical or' tapered. In a cylindrical or slightly tapered ex'- spider.

I furtherv so design the reservoir that a stufng v box is dispensed with and so the loss ofv power it Firstly, `it is difficult to supply the` fuel tothe 10 atomi-zer.` Stuffing boxes or flexible shafts which involvesis eliminated. Instead of astuiing box I provide Aa tube surrounding the shaft and ex- 10 tending beyond the liquid levelin the reservoir at its upper end while its lower end is insertedin the bottom of the reservoir.

Y I further provide a fan or other suitable im- 4pellers for effecting a flow of air past the atom- 15 izer which is preferably arranged on the motor shaft below the bottom of the reservoir. n

I further provide, at some distance from the circular edge from which the fuel is projected by the atomizer, a. shellthe inside diameter cof 20 which preferably increases towardvthe outlet end 'of the burner and' means, such as holes in the web connecting the shell 'to the atomizer, may be provided for admitting air to the interior of the shell. The object of '.the shell is to atomize any 25 vto the mixing tube in a state of extremely fine 30 subdivision. y

Preferably' the burner including the atomizer, the motor and otherparts, is'combined into a vself-contained unit adapted to be connected to the element,v for instance, a liquid heater, which is operated by the burner.

, In order to prevent leakage of unconsumed Y fuelinvatomized nor liquid condition, or products of combustion from the burner, into the atmosphere the means for attaching the self-contained burner to the element heated are arranged in 1 the path of the air moving toward the burner at the suction side of the means, for instance a fan, for effecting the flow of air. Any substances `,which leak from the combustion chamber are intercepted by the flowing air, returned tothe burner and discharged into the flue of the eleend.y ofthe burner. -Air-inlet openings may be .ment to be heate In the drawing affixed to this specification and forming part thereof burners embodying my inventlon are illustrated diagrammatically by way of example. Y

In the drawing f Fig. 1 is an smal section of a self-,contained sa tapered and extends upwardly from the outer,

burner attached to the lower end of an element to be heated, and

Fig. 2 is an axial section of a somewhat simplied burner which may also be designed as a self-contained unit.

Referring now. to the drawing, 2 is the furnace element to be heated, here shown as a flue or combustion chamber surrounded by a water space, and I is an annular extension at the lower end of the furnace element to which the casing of the burner is attached.

Referring now to Fig. l, 36 is an annulus which is secured to the extension of the element 2 by any suitable means, not shown, and 4 Kis the frame of the self-contained burner unit which is secured to the annulus 36 by a flange 31 at its upper end, and screws 3. The frame 4 is a substantially cylindrical member. 44 is a bottom plate at the lower end ofthe frame 4, 45 are screws by which the bottom plate is attached to the frame, and'46 is a flange on vthe casing of a motor |2 which is inserted in a hole on the centre of bottom plate 44. 5 is a fuel tank at one side of the frame, 6 is a container for a supply of fuel from which the fuel is discharged uniformly, for instance, a Mariette flask, and 66 is a check valve at the lower end of the flask which opens automatically by its stem striking a projection 61 on the bottom of the tank 5 when the container 6 is placed in position, lugs 68 being provided for supporting the container at the upper end of the tank 5.

6 is a central fuel reservoir in the frame 4, 1 is a pipe connecting its side wall to the tank 5, and 26 is a pipe connected to the wallA II at the side of the reservoir which is opposite the pipe 1, for a purpose which will be described. 9 is the bottom of the reservoir 8, and I0 is a tube which extends upwardly from the bottom 9 to a point above the liquid level in the reservoir. I3 is the shaft of the motor I2` which is arranged centrally within the tube I0 so that the tube replaces a stuillng box, and I5 is asplder connecting the upper end of shaft I3 to the atomizer I4. The atomizer I4 comprises a tubular extension 40 the lower end of which is below the liquid level in the reservoir 6 and just above the bottom 9, a circular edge |6, a. web I8 which merges into the tubular extension 40 just below the edge I6 and has holes I9, and a shell I1 which is preferably edge of the web I8. ls a. ange on the outer wall of the tubular extension 40.- 4

20 is a baille here shown as a perforated tube which is arranged co-axially in the reservoir 8 intermediate its side wall II and thevtubular' extension 40 of the atomizer. Batlle 20 is shown perforated throughout its length but maybe perforated in its lower portion only, its object being to exert a braking or damping action on the liquid in the reservoir as the liquid must not be entrained by, and rotate with, the extension 40.

The fuel is raised from the reservoir 8 by centrifugal action in the chamber between'the tubular extension 40 of the atomizer and the"tube I0 but, as mentioned, only if the atomizer rotates at normal speed. It is known that when a hollow cylinder which is partly filled with liquid, is rotated about a vertical axis, the liquid will rise and form a hollow body of parabolic section. The section is-determined bythe speed at which the hollow cylinder rotates and intersects the wall of the cylinder at a level which is a function of the speed. By suitably determining the speed .substantially cylindrical.

at which the tubular extension 40 rotates, the liquid is raised beyond the upper edge of the extension where it is atomized under centrifugal action. The extension 40 may be cylindrical as shown or more or less tapered but normally is Any fuel which might creep up on the outside of the extension 40. is stopped by the flange 35.

Arranged below the bottom 9 of the reservoir and secured on the shaft I3 of the motor I2 is a fan impeller 2| which rotates inside the frame 4, and draws in air through an inlet 41 at the upper end of a cowl 28 surrounding the frame 4, and through openings 48 in the frame. It is not necessary to provide the fan 2| if the natural or articial draught in the element 2 is strong enough for drawing combustion air into the burner. The air ows past the pipes or passages 1 and 26 and is distributed to the space surrounding the shell I1 of the rotary atomizer I4 and to the space within the shell, as indicated by the arrows in Fig. 1.

23 is a non-rotary mixing tube which surrounds the shell I1 at some distance and is supported on the upper face of the frame 4 by a flange 49. Preferably the mixing tube 23 is tapered in conformity with the shell I1, i. e., with its inside diameter increasing toward its upper or outlet end. The mixing tube, in addition to its principal function of effecting an intimate mixture of the veils of fuel projected from the edge I6 and from the upper edge of the shell I1 with the air which breaks through the veils, also confines the issuing jet of mixture so that it flows in the proper direction and is not hurled against the flue of the element 2 by centrifugal action. Any non-atomized particles which strike the wall of the mixing tube 23, flow down the wall and are returned to the fuel reservoir 8 through a circular slot 24 formed between the lower end of the mixing tube 23 and an annulus 50 projecting upwardly from the frame 4, and thence through passages 25. In this manner the non-atomized fuel is not entrained by the mixture, to the deterioration of combustion, but returned to the reservoir.

The air inlet 41 at the upper end of the cowl 28 is so lpositioned with respect to the point Where the self-contained burner is connected to the element 2 that the air which is drawn into the burner throflgh the inlet 41, flows past the connection and any fuel, gas or other leakage from the combustion chamber is entrained by the air and returned to the flue 2.

Referring to Fig. 2, the general arrangement of the burner is similar to that described with reference to Fig. 1 but the burner is simplified. The atomizer I4 is here replaced by a plain dish I4', with the edge 6 at its perimeter, and without the shell I1. The tubular extension 40 with the flange 35, the baille 20, the tube I0 surrounding the motor shaft I3, and its spider I5, are provided substantially as in Fig. 1, but slightly modified. The mixing tube 23 has an annular flange 5| at its lower end forming a trough from which a pipe 24' extends to a pipe 25' extending vertically from the supply pipe 1. The pipe 26 is dispensed with, and the reservoir 8 is replaced by a bowl 8', with a tapered side wall II'.

The frame 4 in Fig. l is replaced by a suction pipe 34 which is open at its lower end and in which the motor I2 is arranged. The major portion of the air delivered by the fan 2|, or drawn into the burner by the natural or artificial draught in the flue of the element 2, flows through 1,oss,sse

' the annular passagebetween the wall I I' of the reservoir I' and the inner edge of the flange Il, but a smaller portion is by-passed as secondary air through a tapered passage 3|, between 23 and an extension 3i of the suction pipe $4 which is secured to the outer wall of the mixing tube 23 at its upper end, and openings 32 in themixing tube above the atomization zone. The cowl 2l is here replaced by a pipe I2 which is attached at its upper end to the extension l at the bottom of the element 2 by screws 3 and an annular member 5l, and connected to slots I3 in the pipe 34 at its lower end. By these means any leakage from the combustion chamber is returned to the reservoir but in order to prevent interference with the upward draught in the flue, an annular extension Il is arranged which projects inwardly from the water jacket of the element 2 and is in contact with the outer wall of the extension 3l. It will be understood that the connection at I isheld permanently under reduced pressure by these means and escape of gas or other undesirable matter into the' atmosphere is absolutely prevented.

I wish it to be understood that I do not desire to be-limlted to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:-

1. In combination with a furnace to be heated, oil burning apparatus comprising a frame which is adapted to be connected to, and to make a tight fit on said furnace, and is in open communication with the combustion chamber of said furnace, a central annular Vfuel reservoir in said frame whose upper end is also in open communication with said combustion chamber, a fuelsupply tank at one side of said frame, means in said fuel-supply tankfor maintaining the fuel level therein, a pi`pe connecting said reservoir and said tank, and supporting said tank on said frame, a motor in said frame, a shaft extending from said motor upwardly through said reservoir,

,an atomizer munted on said shaft above said reservoir, a tube extending downwardly from said atomizer and into said reservoir,A and a fan on said shaft below said reservoir.

2. In combination with a furnace to be heated, oil burning apparatus comprising a frame which is adapted to be connected to, and to make a tight flt on said furnace, and is in open communication with the combustion chamber of said furnace, a central annular fuel reservoir in said frame whose upper end is also in open communication with said combustion chamber, a fuelsupply tank at one side of said frame, means in said fuel-supply tank for maintaining the fuel level therein, a pipe connecting said reservoir and said tank and supporting said tank on said frame, a motor in said frame, a shaft extending from said motor upwardly through said reservoir, an atomizer mounted on said shaft above said reservoir, a tube extending downwardly from said atomizer and into said reservoir, a ran on said shaft below said reservoir, and a collector for vunconsun'ied fuel arranged at the top of said frame and connected to said pipe.

HUGO JUNKERS.

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