US1587249A - Method of and apparatus for burning oil - Google Patents

Description

June l 19H26.

F, c. STARR METHOD OF AND APPARATUS FORv BURNING OIL Filed oct. 25. 1922 v lHlll lll l e:

/a TTORNEY Patented June 1,' 1926.

UNiTEDsrAjres PATENT 1 oFFicEf.

FLETCHER COLEMAN `STARRa oP PHILADELPHIA, PENNSYLVANIA, AssI'GNoR To i RrNGsLnY L. MARTIN, or MoNTcLAIR, NEW JERSEY.

METHOI) or AND APPARATUs PoR BURNING on..

-Alpiie'aaon aiea'october 23, 1922. 'serial' No. 596,275.

lThis invention relatesto -a method.v and apparatus especially intended or 'adapted for burningoil and 'other liquid orsemiliquid `fuel, and aims to providea method and apparatus of greater flexibility and siii-'- ciency than the methods and apparatus heretofore used. rThe invention comprises' a '.method wherein'the'oil'or other liquid fuel is atom- "ized by means ofv 'steam or air or other suitable gaseous i medium under pressure and dischargedin. the form of a hollow cone,

.and the invention includes also apparatus for practicing the method.

Before my invention, oil has been burned efciently inboiler furnaces and other fur-4 naces in two ways, that is, by the use of mechanical atomizers by which the oil is discharged in theforin of a hollow cone to which air is supplied from a register or adjustable airinlet means surrounding the atomizer,'and `by the use ofsteam or air atomizers b y which the atomized oil `1s discharged with the steam or air in solid sprays of variousl forms. The' use of steam atomizers for spraying the oil has important advanta es over the use of mechanical. n-the other hand, the spray? apparatus. i ing of the oil in the form of a hollow cone from a mechanical atomizer set in an air register has certain advantages over the use of solid sprays.

The method andapparatus. of the present invention combines advantages of both me'- chanical atomization and steam or air atomization by spraying the fuel in the form of a hollow cone from a steam or air atomizer set in an air register or inlet pas-A sage through'which air for supporting combustion is'admitted to the outer side of the spray cone. In burning Aoil in this way there is secured also certain additional advantages which are not obtained with either of the old methods.. The oil burning capacity 'of the burner apparatus under an available draft is greatly increased because of the greater permeability of the spray which permits the air to penetratethe cone wall and mix with the 'fuel more readily, and because of the greater voluine and sustained velocity' of the spray which tends to increase the air iiow. Also the spray cone retains itsr shape or angular width, and the same fineness. of atomization may be maintained, through a very wide capacity range, thus panyin'g 4drawings illustrating an oil burninsuring `proper air mixture ina given size i burner opening in' the furnace wall throughout a wide rangeiof capacity.

A full understandingof theinvention can ',best be given by a detailed description of an apparatus of approved form made in accordance with the invention, andthe operation thereof, and such a description will now be given in connection with the accomthe form of a hollow conefiniaccordance with the invention;

, Fig 2 is a View of the frontend of. the atomizer shown in Fig. 1; i

Fig. '3 isa sectional view of', an cil burning apparatus comprising an atomizing device suchas shown in Figs. 1 and 2 set in an air register mounted in a burner opening in a furnace Wall; and

Fig. 4 is 'a front view of an yorifice plate having a modified forni of orifice.

Fig. 5 illustrates another'form of orifice.I Y

Referring to the drawings, the atomizing device comprises a body 10 formed with an opening orbore extendinginward from its front end in which is fitted aremovable plug 11 formed with a throat or passage'12 opening from its rear end and an enlarged chamber 13 in its -forward portion, the throat 12 opening into the chamber 13 and the chamber 13 opening through the' front end of the lug.k The rear portion of the plug 11is ot reduced diameter' so as to provide an annular chamber 14 within the body 10. The body 10 is also formed with a central opening-orchamber 15, the forward wall of which is formed by the rearend of the plug 11'and from which the passage or throat 12 opens. From the chamber 15 a bore or opening extends to the rear end of the body 10, the inner end of which bore is of reduced diameterand threaded to receive .a nozzle 16, andthe outer end of which is fuel is,v supplied-to the'chamber 15. from a n P 'supply pipe 21. 1 Steam or air or other gaseous ,medium under pressure is. supplied through a supply pipe 22 to an inlet passage 23formed in the body 10 and 'which communicates through a port 24 with the chamber 18 and also communicates with the` passage 14. A cap or-plate 25 held against the front end of the body by means of a ring nut 26 forms the front wall of the mixingchamber 13 and is provided in the apparatus shown withv a Aplurality of discharge orifices 30.

The liquid fuel, which may be fuel oil or crude. oil or .other suitable oil or tar or other suitable liquid or semi-liquid fuel, is supplied to the inlet passage 20" under pressure sufficient-to maintain a supply of the fuel liquid in the chamber 15. The nozzle 16 and throat or passage 12are arranged in axial alignment, and the rear or entrance end ofthe throat is somewhat flared and the nozzle is set to extend into the chamber 15 andsuita'bly close to the flared entrance end, or entrance cone, of the throat, so that the jet of steam or other gaseous medium discharged from the nozzle into the throat will act to induce flow of the fuel liquid from the chamber 15 into the throat and to drive the same thrdugh the throat into the chamber 13. The fuel liquid thus driven through 4the throat 12 by the jet of steam or other gaseous medium is thereby broken up or partially atomized and mixed with the atomizing medium.

Leading from the annular passage 14 are a plurality of small passages or ports 35 vfor discharging jets of the steam or other gaseous atomizing medium into the chamber 13 for further atomizing the fuel liquid and maintaining the fluid in the chamber 13 in motion and the finely divided, or atomized, fuel liquid in suspension in' the gaseous medium. These ports 35 are most desirably arranged to deliver the atomizing medium in a direction more or less tangential to the stream of atomizing medium flowing from the throat 12 so as to impart a whirling motion to the body of atomizing medium in the chamber 13 with its atomized fuel in suspension therein; and the discharge ends of these ports are most desirablv locatedlat the end of the passage'12 so that the jets issuing therefrom will be directed into the chamber 13. and will strike the stream of atomizing medium and partially atomized fuel as it flows from the passage 12 into the chamber 13. The vatomizing medium withy the atomized fuel carried therebyT is discharged through the discharge orifices 30.

lt will be noticed that as shown in Fig. 1 the rear wall of the chamber 13 extends outwardly at right angles from the wall of` the passage 12. Having the rear wall of the chamber'extend away from the end of the passage at approximately a right angle seems to have an effect in securing albetter j atomization at this point. l

ln the operation of the atomizer, a body of the gaseous atomizing medium under pressure is maintained in the chamber 13 with the finely divided, or atomized, fuel in suspension therein, gaseous mixture from this body constantly being discharged /through the discharge orifice or orifices, and the body being constantly renewed by the stream from the throat12 and jets from the ports 35 in the form of atomizer shown. By suitable arrangement of the discharge orifice or orifices, the spray discharged from the chamber 13 may be given practically any desired form. Not only may solid sprays of various forms be produced, but a spray in the form of a hollow, and hollow cone y sprays of other forms having relatively thin walls, may also be produced.

A hollow cone spray may lbe .produced by providing the chamber 13 with athin front wall such as the cap 25 shown in Figs. 1 and 2, of outwardly bulging form and pro,- vided with an annular or circularly arranged series of discharge orifices 30 arranged concentric with the axis or center line of the burner. The gaseous medium with the atomized fuel will. be discharged through -.these orifices in a'series of outwardly directed separate jets which as they expand merge together and form a hollow conical spray. The angular width of the spray cone'will depend upon the arrangement of f the orifices, and the thickness of the cone wall will depend upon the size of the orifices. In the device shown, in which the orifices 30 are formed i'n` a thin cap plate, the direction of the individual jets and the Y angular width of the spray cone will be determined. by the angle to the burner axis of the part of the inner wall of the cap plate in which the orifices are located, since the direction of the pressure of the fluid at the orifice will determine the direction of the jet. The invention is, however, of course not limited to the use of a vthin orifice plate having av curvature which determines the jet direction, as the orifice may be otherwise formed to give the-desired angular direction to the spray.

rl`he series of orifices 30 arranged as shown may be considered as an annular orifice divided into a plurality of separate discharge openings for the purpose of producing a plurality of circularly arrangedseparate( but closely spaced jets which at a short distance beyond the orifice plate unite to form a closed or Vcircumferentially continuous spray cone wall. The use of a series of closely spaced separate openings has certain advantages, but the invention is, of course` not limited to the use of such a divided orifice, and an orifice formed of one or more slots might, of course, be employed. Fig.

4 shows, for example, an orifice plate having an annular orifice formed by three slots 30. f. l y 4 Combustion air is most desirably supplied to the hollowl cone spray, by setting the spray nozzle or atomizer in an air register,

or air inlet opening, for supplying a flow' of air againstthe outside ofl the cone in the saine manner as is the practice with mechanical atomizers producing hollow cone sprays. An arrangement 1s illustrated 1n Fig. 3 which shows an atomizer A ofthe construction shown byvFigs. l and 2 set inthe center. oflan air register B mounted on a furnace.

Wall 40 with the atomizer in position to discharge its spray cone centrally through a burner opening in the wall. The burner` opening is provided with a tire-brick ring' 41 of suitable form,.-and the4 lsize of the burner opening through the rin-g 41 and the position of the atomizer'is such that the spray cone will substantially till the 'opening without having the sprayed fuel strike against the wall of the opening, or surface of the ring 41. Theair register or means for admitting air 'around the atomizer under the suction of the furnace draft, or, as it might be, under forced draft, may be of any suitable construction. An'air register o'f known form is sho-wn constructed to provide a main annular air inlet 42 and a series of inlet openings 43 immediately about and extending in close to the atomizer. An ad.` justable plate 44 having openings .cor-responding to the air inlet openings 43`may be provided for adjusting'theeifective size of the openings 43; and adjustably. pivoted .shutters 45 may be provided for controlling the amount of air entering through the main air inlet passage42, and for givlng the enter' ing air a revolving or spiral movement. The

annular air inlet passage 42 is advantageous-y4 -ly shaped as shown to direct the air inward ly in a converging'streamagainst the spray cone, and the irebrick ring 41 is desirably y. curved toprovide a wall extending as a continuatio'n of the outer wall of -the vair register latomizing fuel by means o inward toward thepath of thespray cone, and then outwardly, thereby providing a burner opening inpassing through which the spray cone will exert a greater flow inducing action on the air than would be the case if the wall of the burner opening were not so formed. The invention is not,v however, limited to any particular form of burner opening.

The method of burnin gascous medium under pressure anddischarging the mixture. of fuel and gaseous medium in the form of a hollow cone and' directing combustion supporting air against the outside of the cone, and apparatus comprising means for atomizing liquid fuel b-y'a gaseous medium underA pressure and dischargingthe mixture in a liquid fuel by hollow cone spray set in an air register or than a steam atomizer set in an' air register and'discharging ahollow'cone spray. Com- 8 vair inlet means for supplying air to the outimv parative tests haveshown that in so burning an equivalent amount of oil a steam atomizer burnerrequires only about -one-half to onetliird of the draft required by al mechanical atoinizing burner. This greater capacity of the 'hollow cone spray steam atomizing burner is probably due to the greater diifusion of the oil in the-spray andgreater permeability of thesteani and atomized oil spray as compared tothe spray from a me chanical atomizer; and 4also to the greater volume and higher sustained velocity of the steam atomized spray resulting in stronger iiow4 inducing action on the entering air.

The wall of the s ray cone is also ermeable to the air consi erably closer to t e discharge oriiice than is the case with a inechanically atomized hollow cone spray. This is so even if the spray is discharged from an orifice in the form of a'continuous or uninterrupted slot, and whenthe spray is discharged froin an oriceformed by a series of closely spaced separate openings, as shown 1n Fig. 2, the open spaces between the separate jets close Ato the oriiice plate afford opportunity for ready entrance of air striking the spray at this point.

The burner construction of the present invention willalso operate etliciently through a much greater capacity-range than a burner discharging a mechanically atomized hollow cone spray. This greater flexibility is due not only tothe characteristics?` of steam or air atomization which give a greater iieXiy bility in discharging the fuel i-n a solid spray, but also to the fact that the hollow spray cone retains the saine angular width at all rates of oil consumption within the limits of the burner and furnace. The 4angular width of the cone of a hollow cone spray Jfrom a Steam or air. atomiz'er is, as stated,'

fixed by the form and arrangement of the discharge orifices, and does not depend, as 4 is the case with the mechanical atomizer, on the velocit)v of rotation and resulting centrifugal force. As in discharging the fuel in a solid spray from a steam or air atomizcr, so also iii discharging the fuel iii-a hol-.v

low cone spray, the same fineness of atomization may be secured at all rates of oil consumption within the range of the apparatus.

It may be noted that when steam is employed as the atomizing medium,- or if other atomizing medium employed is preheated to 'a sufficient degree, the oil is more or less vaporized before being discharged from the atomizer. s

vA further very important advantage of the present invention i's that it is not limited to the production of a hollow spray which is annular in cross-section, since by using discharge orifices of suitable shapes outwardly spreading hollow sprays of vari- I ous forms in cross-section may be produced.

of an outwardly spreading thin walled hol-` low spray, the fuel being in a finely divided condition 1n suspension 1n the gaseous medium, and causing airto flow against the outer side 'of the spray .wall and to enter the same. f i

2. The method of burning liquid fuel, which comprises discharging a mixture of the fuel and a gaseous medium in the form' of' a thin walled hollow conical spray, the fuel being in a finely divided condition in suspension in the gaseous medium, and causing air to flow against the outer side of the conical spray wall. and to enter the same.

3. The method of burning liquid-fuel, which comprises atomizing the fuel liquid by means of gaseous medium under pressure and discharging the gaseous medium with the atomized. fuel in suspension'therein in the form of an outwardly spreading thin .walled hollow spray through a burner opening of such size and form that the saray passes closely adjacent to the wall o .the

burner opening, and thereby inducing a flow of air into the burner opening andv against the spray wall to enter the same and mingle with the atomized fuel. Y

4. The method of burning liquid` fuel, which comprises maintaining under pressure a body of gaseous medium having finely divided fuel in. suspension therein, discharging the mixture of gaseous medium and fuel in a multiplicity of circularly arranged outwardly directed jets which combine to form aspray in the form of a thin walled hollow cone, and directing air against the outer side of said jets and sbrav cone.

mamas 5. Apparatus for burning liquid fuel, comprising means for discharging a mixture of the fuel and a gaseous, medium in the form of an outwardly spreading thinwalled hollow spray, the fuel being in a finely divided condition in suspension in the gaseous medium, and means for causing air to flow against the outer side of the. spray wall.

6. Apparatus for burning liquid fuel, comprising means for maintaining a body of gaseous medium under pressure with the fuel in a finely divided condition in suspension therein, meansproviding a discharge orifice through which the mixture of gaseous medium and fuel is discharged in the form of an outwardly spreading thin walled hollow spray, and means for causing air to fiow against the outer side of the spray.

' 7. Apparatus for burning liquid fuel, comprising means for maintaining a body of gaseous medium under pressure with the fuel in a fil' ily divided condition in suspensionv therein, means providing an orifice through which the mixture of gaseous medium and fuel is discharged in the form of a thin walled hollow cone, and means for causing air to fiow lagainst the outer side of the spray cone.

8.. Apparatus for burning liquid fuel, which comprises means for maintaining a body of gaseous medium under pressure withthe fuel in a finely divided condition in suspension therein, means providing a discharge orifice formed by a series of separate closely spaced circularly arranged openings for discharging the mixture of gaseous mecausing air to flow against the outer side of the Spray cone.

9. Apparatus for vburning liquid fuel, comprising an air register mounted on a furnace wall having a burner opening therein extending from the air register; and an atomizing device set in the air register comprisinga chamber having a discharge orifice opening from the front thereof, and means for supplying to and maintaining within the chamber a body of gaseous medium under pressure with the fuel in a finely divided condition in suspension therein, the discharge orifice being formed to discharge the mixture of gaseous medium and fuel from thechamber in the form of an outwardly spreading thinvwalled hollow spray which passes closely adjacent to the wall of the burner opening and is of cross-sectional form corresponding to the shape of the burner opening.

lntestimony whereof l have hereunto set my hand.

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