US1839527A - Hydrocarbon burner - Google Patents

Description

Jan. 5, 1932. A. H. BATES 1,839,527

HYDROCARBON BURNER Filed June 7, 1928 Patented Jan. 5, 1932 new new secretes rema ermieseae a eearaa Applicationfiled June 7', 1922;. Serial no; 283,483.

This inventionrelates to what are Qordie narily known as hydrocarbon burn'ers,,but more particularly stated has-reference to a device for intimately mixing fluid 'or p0W-: (lei-ed fuels and air to form acombustible mixture.

Hydrocarbon burners operating with the heavier oils, such as those lower than 20 degrees Baum, have been found to give trouble particularly because of the clogging of the relatively small supply orifice's It is,

therefore, an important object of myinvention to provide aburner having preferably only one large feed pipe without sharpvbends which will have very little tendency to .clog' and Which, at any rate, can be easily-cleanedi Another common objection to many, burners has been the need for elaborate air controls as well as a number of fuel feed adjustments;

, It is, therefore, another object of my invention to provide a construction necessitating only one airvalve and one fuel valve,rmak-- ing it much more economical to produce as well as simpler to manipulate.- Stillanotheh 1 objection to manyburnershas been the need for a high pressureair supply which involved higher operating costs and. intros duced various practical difiiculties.- lt is, therefore, still another object ofamy inven i tion to provide aburneradaptedtooperate' with air under lowpressure, this being-rendered feasible by virtue ofmultiestage atom-l ization provided forin'an especiallynovel and effective manner. 7 Y I The invention embodies various-important features in the carrying out of the foregoing objects, such, for example, aslthe novel form and arrangement of the fuel feed pipe whereby fuel is supplied at right angles to the air stream at the point 'of highest veloc ity; the novel form and arrangementofvene tui'is, consisting. in disposing the end of one venturi at or near the throat of the second, and so on, and also disposing the ends-of the venturis slightly-eccentric with respect to the throats, above the centers thereQf, 1 f u' e h pi ng up -1a y. fue dripp ng or seeping from: one venturi into an ther; th a e o tru t-ion an ar angement hich Pe mit of aaiadi ustment vl1three the turisnest of venturis and the casing to afie'ct the shapeor cross-section of the flame, and the novelorganization and arrangement of parts which-enables not only the probing of the fuel feed pipe from without the casing to quickly clean thesame in case it tends to clog, but also permits the removal from the casing of all vof the venturis With the feed pipe, the venturis being fixed to and adjustable With the latter. c I The invention is illustrated in the accompanying drawings, wherein,

. Eigure l-is a central vertical longitudinal sectir'm throughfan oil burner embodying my nvent on; Y

;-E ig. 2-is aisection taken on the line 22 of Fig; 1 looking in the direction of the arrows-rand i i I ,Eig. 3 is a longitudinal section'through a modified. or alternative. form of nested ven- I, Thesame reference numerals are applied to corresponding parts in the two views.-

Ti lie-burner,- illustrated is of a type especially designed for industrial usage, as, for example, in forging, or in connection with heat treating furnaces, for carbonizing,- and forgheating core and drying ovens, etc. .As stated-above, the burner is adapted for operation withoilsas' heavy as QO'degrees Baum, and lower, although, of course, no special limitation should be regarded as imposed on the use of the inventionby-reason of this statement, inasmuch as the invention is, as a matter of fact, not limited'to use With any particularkind of fuel. Furthermore, the? burner of the present invention with slight modification is adaptable for domestic heating purposes inasmuch as it will operate with such'light oils, as furnace oil and even lighter, oils. i

q The. burner, generallyjstated, comprises a casing aps ubstantially T,-shaped: as shown, having connection at 56 witha' conduit 7 arranged to be supplied with, air under a pressure as low as fourounces, the burner being adapted t op r t best wi h a ra ge cof pre ure b t ee f a d sixt en ounces; as limitation, hew rer, o lde reg rded as impo d e -the app c t o of h in ent on by reason of any reference to air pressures or, for that matter, fuel pressures. The cross-portion of the T-shaped casing 5 communicates at one end with the fuel supply pipe 8 through which oil or other fuel is delivered under a pressure of, say, from s1x to twenty pounds, and has the other end extended, as appears at 10, to discharge the combustible mixture of the intimately mixed fuel and air into the furnace. The boss 11 provided on the casing 5' is one point at which a bolt on a supporting bracket for the burner is arranged to have engagement with the easing to hold the same in a certain desired adjusted position. The air supplied to the burner is arranged to be regulated in any manner by any suitable Cir-preferred form of valve such, for example, as a butterfly valve 12 operated-by a suitable handle 13. The fuel supplied to the burner is in turn arranged to be regulated by the setting of a valve 14. The fuel is delivered into the casing 5 through a feed pipe 15 after passage through a screen 16. The latter is removable upon removal of the plug 17 and the removal of the latter also affords access to the pipel5 so that a wire or other form of probe may be inserted to clean out the pipe from end to end in case the same ever becomes dirty enough to require cleaning. From the description thus far it will be observedthat only one air valve'and one fuel valve are required. The cost of the accessoriesis', therefore, kept to a minimum,but, still more important, the matter of controllingthe operation of the burner is greatly simplified and its all-around performance is better. The ability to operate the burner with air under the low pressure mentioned and the fact that only one air valve isneeded may be attributed to the multi-stage atomization provided for in accordance with my invention, as will hereinafter appear; In multi-stage atomization the fuel is partially atomized in the first stage, isatomized still further in a second stage, and so on, with the result that atomization is bound to be complete by the time the mixture is discharged from the burner into the furnace; the condition of having the particles of fuel brought into contact with a large amount of air all at one time is avoided, and, instead, air is added in several stages to reatomize the fuel and thus thoroughly break it up into a' form in which it burns readily without much smoke and gives ofl maximum heat.

The fuel feed pipe 15 may or may not be provided in one continuous length extending from thevsupply pipe 8 through the plug 18 to thenested venturis 19 and 20. The latter are arranged to cooperate with the tapered end 21 of the casing to provide three stages of atomization, as will presently appear. Any'number of stages might, however,

e provided for by mcreasing' the number of venturis. Furthermore, while the venturis 19 and 20 are represented as being circular in cross-section, as shown in Fig. 2, it should be understood that they might be elliptical or'rectangular in cross-section without seriously affecting the operation. In fact, in certain furnaces it is desired to have the flame spread out in a sheet and in such cases the venturis will be made correspondingly broad either in an elliptical or rectangular form. The relationshipshereinafter referred to would not be affected thereby. The venturis 19 and 20 which, for convenience may be referred to as the primary and secondary venturis, respectively, are suitably held in a predetermined fixed relation to one another as by means of webs 22 formed in the casting thereof. The venturis may be arranged concentric with each other and with the casing end 10, although, as shown I prefer to have the centerof the primary venturi slightly above the center of the second venturi, and the center of the second slightly above the center of the third, and so forth, the end venturi having its center slightly above the I end of each venturi for a'purpose presently to appear. While the venturis are shown as having their longitudinal axes parallel with one another, it will be evident that the offset relation just described might be arrived at by inclination of the axis of one venturi with respect to the next in a manner believed to require no explanation. The primary venturi, it will be noted, ends at or near the throat of the secondary venturi; in other words, at the narrowest portion of the latter, lfzmore than two venturis were shown, it should be understood that the second venturi would terminate at or near the throat of the third venturi and that the third would terminate at or near the throat of the fourth, and so forth. The secondary venturi 20, which, in the present instance, is the endmost venturi, may. be provided with any suitable means for supporting the same in proper spaced "relation to the inside of the casing. Knobs 23 projecting substantially radially in circumferentially spaced relation from the venturi 20 have rounded ends slidably engaged within the discharge end 10 of the casing as shown. The knobs are illustrated as threadedly engaged in the walls of the venabovethe center for a similar purpose as in the case of the offsetting of the primary venturi relative to the secondary venturi. The outer "end of the secondary venturi is chamfered externally, as appears at 24, to conform approximately to the shape of the tapered end 21 of the casing. The fuelfeed pipe 15 has its inner end angled, as appears at 25, and extending through a hole 26 provided in the Wall of the, primary venturi extending at an acute angleto the longitudinal axis of the latter. The hole 26 is so located and the inner end of the feed pipe 15 projects sufficiently into the venturi that the fuel feed opening 27 is fully exposed forwardly in the air stream passing through the venturi and the drip edge 28 is practically at the center of the venturi at or near the'throat thereof. 7 V

In operation, assuming that air is being supplied to the casing 5 through the conduit 7' and oil or other fuel is being supplied to the feed pipe 15 through the supply pipe 8, the fuel enters the primary venturi at or near its throat where the air is at its highest velocity. Consequently, the fuel is positively broken up into finely divided particles, each of which is enveloped and entrained in the air passing through the venturi. It will be understood that the fuel is fed in very small amounts in proportion to the air and that, particularly in the case of oil, it forms in drops or globules at the edge 28, which, as stated before, is where the air attains its highest velocity in passing through the' primary venturi. Due

to the form and relation of the delivery end of the fuel f-eed pipe there is no back-pressure exerted on the fuel by the air stream as, for example, would be the case if the fuel feed pipe terminated flush with the inner wall of the venturi. The mixture of fuel and air emerging from the primary venturi, as a result of the first stage of atomization, is'enveloped by an air stream in the secondary venturi. Since the primary venturi terminates at or near the point of greatest restriction in the secondary venturi, it will be evident that the mixture of fuel and air leaving the primary venturi is acted upon by air at the highest velocity attainable in said venturi, thus further atomizing the fuel in what I prefer to designate a second stage of atomization. Furthermore, it will be evident that'any fuel draining from the primary venturi will drip into the secondary venturi crosswise of the second air stream at the throat, where, as just stated, the air attains the highest velocity through the secondary.

venturi. The particles of fuel are thereby positively broken up. Very little, if any, of the fuel is apt to be left in a solid form after two stages of atomization excepting perhaps when using heavy fuel and especially fuel which has not been preheated to facilitate atomization thereof. However, as-

stated above, if additional stages of atomization are desired, additional venturis may be provided. The offset relation of the primary venturi to the secondary venturi is of advantage in that there is ample exposure to the a r stream ofany drops or globules of fuel forming on the under side of the primary venturi at the forward end thereof. Likewise, after the second stage of atomization, any fuel forming on the forward end of the secondary venturi is struck by a third air stream passing about the secondary venturi and issuing from the casing through the opening 29. The offset relation of the end of the secondary venturi to the opening 29 likewise insures best exposure of the fuel to the air stream. The third air-stream, which, in this instance,is annular in form, like the second air stream, is converged toward a point at a certain distance in front of the opening 29 due to the deflecting action at the tapered portion 21.

The feed pipe 15 is adjustably received in a hole 30 provided in the plug 18 and the ad justment fore and aft of the nest of venturis whichresults when the pipe is moved in or out affects the shape or cross-section of the vol flame; that is to say, forward adjustment of e the venturis straightens and lengthens the flame whereasrearward adjustment thereof spreads the flame. The set screw 31 serves to hold the fuel feed pipe in any adjusted position. tatably adjustable with respect to the casing and is arranged to be locked in position by another set screw 32. It will be evident thatthe plug 18, may be removed with the fee-d pipe 15 and that the nest of venturis being mounted on the feed pipe may be removed from the casing at the same time, thus permitting inspection and cleaning of the burner whenever desired. Disassembling and reassembling the burner need not affect any of the adjustments. I

Referring to Fig. 3 showing a modified or alternative form of nested venturis it willbe observed that the venturis 19, 20 and 21 in this. instance, are castintegrally having the upper wall 33 common to the three venturis. In other words, the venturis are disposed eccentric with respect to one another, each above the center of the next. It will also be seen that each venturi terminates at or near the throat of the next venturi. Substantially the same operationis obtainable with these venturis as 'with the ones previously described insofar as multi-stage atomization is concerned and also as regards the atomization of particles of fuel draining from one venturi into the next; any collection of fuel onthe lower edge of the outlet end of any venturi is fully exposed to the action of the airstrea-m. In this' case, as in the other, it is obviously immaterial whether the venturis arecircular incrossssection or whether they are elliptical or rectangular in cross-section. It is believed the foregoing description conveys a clear understanding of my invention and of its various objects and advan- The plug 18 is slidably and ro-j tages. Whilereference has been made in the foregoing description to certain specific details of construction and arrangement it should be understood that the same are capable of modification. For that reason the appended claims have been drawn with a view to covering any changes comlng within the spirit and scope of the invention, consistent, of course, with the state of the'prior art.

I claim:

1. A device of the character described comprising, in combination, a casing having coinmunication with a source of air supply under pressure and having an outlet opening, a plurality of nested atomizer tubes of graduated sizes mounted in said casing behind the outlet opening, the smallest or primary tube being disposed rearmost with its outlet end in the intake end of the next tube, and so on, one tube being disposed with the center of its outlet end abovethe center of the intake end of the next tube, and means for supplying fuel to the intake end of the primary tube.

2. A device of the character described comprising, in combination, a casing having communication with a source of air supply under pressure and having an outlet opening, a plurality of nested atomizer tubes mounted in said casing behind the outlet opening with the smallest or prlmary tube'disposed rearmost, the outlet end otone tube being disposed within the intake end of the next, and so on, at least the foremost or largest tube being disposed with the center of its outlet end above the axis of the outlet end of the casing for the purpose contemplated, and means for supplying fuel to the intake end of the primary tube. a r

3. In a device of the character described, the combination with a casing arranged to communicate with asource of air supply under pressure and having an outlet opening, and a fuel feed pipe extending into said casing, of a plurality or Venturtshaped nested atomizer tubes of graduated sizes mounted in said casing behind the outlet opening with the smallest or primary tube disposed rearmost and having the fuel feed pipe communicating with the throat thereof, the said tubes icing cast integral with one another with the outlet end of one tube in the intake end of the next tube, and so on, the tubes being furt ier disposed so that one tube has the center of its outlet end above the center of" the intake end of the next tube, the setof tubes thereby constituting a unit for easy insertion and removal from the casing as well as for adjustment therein, and the predetermined desired relationship between each tube and the next larger'tube being also thereby permanently assured.

- In witness of the foregoing I affix my signature. 7

. ALBERT H. BATES.

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