US1980132A

US1980132A - Liquid fuel burner

Info

Publication number: US1980132A
Application number: US645916A
Authority: US
Inventors: Fletcher James
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1932-12-06
Filing date: 1932-12-06
Publication date: 1934-11-06
Anticipated expiration: 1951-11-06

Description

Nov. 6, 1934;

J. FLETCHER LIQUID FUEL BURNER Filed Dec. 6. 19.32

annllnllllm INVENTOR B elf-:mes lflecher- ATroRNEY Patented Nov. 6, 1934 UNITED "STATES LIQUID FUEL BURNER.

James Fletcher, Akron, Ohio, assigner to The Babcock & Wilcox Company, Newark, N. J., a corporation of New Jersey Application December 6. 1932, Serial No. 645,916 19 Claims. (Cl. 299-140) My present invention relates to the construction and operation of liquid fuel burners, and particularly to liquid fuel burners in which the liquid fuel is atomized by a high pressure atomiz- 5 ing fluid. My improved fuel burner is especially adapted for burning low grade fuels, such as the heavy residual oils, tar, pitch, and acid sludge found in modern petroleum refineries. With such fuels, the problem of maintaining the burner in I0 an operative condition is more complex than Wi-th higher grade liquid fuels, due to the increased tendency of the burner passagesto be clogged by carbon and Waste deposits.

The general object of my invention is 'the provision of a liquid fuel burner capable of eifeetively atomizing liquid fuel and maintaining desirable flame conditions over a wide range of fuel capacities. More particularly, the object `of my invention is the provision of a' liquid fuel burner capable of efficiently atomizing and burning low 'grade fuels of the character described over a wide range of fuel capacities. A further object is the provision of a liquid fuel burner in which low grade liquid fuels can be burned with a minimum of Waste and carbon deposits in the fuel passages.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific yobjects attained by its use, reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described preferred embodiments of my invention. A

Of the drawing:

Fig. l is a sectional elevation of one embodiment of my invention, -certain parts being omitted or broken away for purposes of clarity;

' Fig. 2 is. an end view of the fuel burner illustrated in Fig. 1;

Fig.v 3 is a front view on an enlarged scale of the sprayer plate shown in Fig. l;

Fig. 4 is a sectionon the line 4-4 -of Fig. 3;

Fig. 5 is a sectional elevation on an enlarged threaded, as indicated at l1, for supporting a 'Ihe liquid fuel burner unit illustrated in Figs.

suitable impeller (not shown) which directs a flow of combustion-supporting. air relative -to the discharge end of the burner, the impeller being advantageously positioned and the burner mounted substantially as shown in the prior Patent No.

1,602,180 to T. B. Stillman, granted Oct. 5, 1926. 'I'he fuel burner proper is slidably mounted in the casing 10,. and consists of a barrel 12 extending axially within the casing 10 and spaced therefrom by longitudinally spaced centering'collars 65 13 and 14. The rear end of the barrel 12 extends beyond the rear end of the collar 14 and is threaded into a body member 15, formed with a passagev 16 therein connected to a suitable source of atomizing fluid, as hereinafter described, While' va- 70 rious atomizng fluids may be used to advantage, steam is the most economical, and that term is generically used hereinafter to include any suitable atomizing fluid. Withinand extending axially beyond the ends of the barrel `l2 is a. pipe 75 17 serving as Athe liquid fuel conduit of the burner. Ihe rear end of the pipe 17 extends across the passage 16 and is connected with a separate passage 18 in the body member, the passage 18 being connected to a suitable source of liquid fuel, 80 as hereinafter described. .f

The forward or discharge end of the burner is formed by a discharge head including a sprayer head 20 having its forward portion closely fitting around the slightly reduced forward end of the pipe 17 and a rear portion abutting and threaded on the forward end of the barrel 12. The forward end of the. sprayer head has an annular recess 21 connected to the annular steam supply passage surrounding the fuel pipe 17 by a series of parallel 90 passages 22 symmetrically arranged about the axis of the sprayer head. As illustrated in Fig.

1 the forward end of the sprayer head is coextensive with the forward end of the pipe 1'1.

The discharge head also includes a sprayer plate 25 through which the steam is brought into atomizing relation with the liquid fuel. As shown in Figs. 1, 3 and 4, the sprayer plate has an annular recess 26 formed in its forward face in alignment with the recess 21 of the sprayer head and 100 connected thereto bya series of symmetrically spaced ports or passages 27 arranged parallel to the axis of the sprayer plate. The central portion of the forward face of the sprayer plate is also counterbored to form a mixing chamber 28. The supply of liquid is delivered to the mixing chamber from the pipe 1'1 through a series of ports or passages 29 extending parallel to the axis of the sprayer plate and -having their centers symmetrically spaced on the circumference of the mixing chamber. The number of ports 27 provided is advantageously greater than the number of ports 29 to insure an adequate supply of steam to the recess 26 and a minimum steam pressure drop through the burner. The steam lchamber or recess 26 is connected to the mixing chamber 28 by a series of steam discharge slots or nozzles 30 formed in the substantially annular wall 31 between the two chambers. Each discharge slot is arranged to extend radially from the periphery of a corresponding port `29 to the recess 26, opening thereto adjacent the point of entrance o f a corresponding port 27. The slots 30 are all similarly angularly arranged relative to the circumference of the mixing` chamber 28, the center line of each extending within but adjacent to the circumference of the mixing chamber. When so proportioned and the centers of the ports-27 at twice the distance of the ports 29 from the center of the mixing chamber, the angle A between the radii from the center of the mixing chamber through the centers of each port 29 and the corresponding port 27, will be approximately 26". The slots 30 are preferably of rectangular cross-section with a width about half the diameter of the ports 29 and with tl .r bottoms in the same plane as the bottoms of the recess 26 and mixing chamber 28.

The discharge head also includes a nozzle member 32 of substantially the same diameter as the sprayer plate 25, and having a plane rear surface abutting the forward side of the sprayer plate and defining the forward side of the steam chamber 26 and discharge slots 30. The machining operations required are thus mainly confined to the sprayer plate. As shown in Figs. 1 and 5, the nozzle has an axial discharge passage divided into a rear portion 33 aligned with the periphery and forming a 'continuation of the mixing charnber 28 and a forward conical portion 34diverging from the forward end ofthe rear portion 33. I have found that the best flame conditions for a wide range of fuel capacities is obtained with a sprayer plate of the character described in conjunction with a nozzle of the character described having an included angle B of approximately 55. The circumferential inner forward portion of the nozzle 321s cut away to provide a seat for va cap member 35 which fits around the nozzle and sprayer plate and holds them in their intendedl positions relative to the sprayer head 20 and pipe 17. The rear end of the cap member 35 is internally threaded at 36 for engagement with the externally threaded forward portion of the sprayer head. When acid sludge is used as the fuel, the burner parts normally contacted thereby are preferably made of suitable acid-resistant alloys.

steam and liquid fuel supply connections to the.

body member 15 are advantageously flexible and readily detachable from the body member. As shown in Figs. l and 2, the rear end of the casing 10 is externally threaded for engagement by an adjustable collar 40 having pairs of wings 41 on opposite sides thereof carrying pivot pins 42 for upper and

lower clamp arms

43 and 44, respectively. The portions of the body memberv 15 at the rear ends of the passages 16 and 18 are beveled as indicated in Fig. 1 to receive thel rounded ends of ball joint nipples 45 carried in the

clamp arms

43 and 44. The nipples 45 are threaded at their other end to provide a connection to exible steam and liquid

fuel supply lines

46 and 47, respectively. I'he free end of the clamp arm 44 carries a pivot pin 48 onwhich a clamp bolt 49 is mounted. The upper end of the clamp bolt is adapted to be received in the forked free end of the clamp arm 43 and is ordinarily held in that position by a washer 50 and clamp nut 51.

With the supply connections in their operating position, as shown in Fig. l, inspection and/or cleaning of the burner parts is easily .effected after the supplies of steam and liquid fuel have been cut off, by loosening the clamp nut 5l and swinging the clamp bolt out of engagement with the clamp arm 43. The

clamp arms

43 and 44 may then be swung out of position carrying therewith the nipples 45. The burner parts within the casing l0 may then be withdrawn without disturbing the position of the latter.

In operation with a fuel burner constructed as described, the liquid fuel, preferably preheated to decrease its viscosity and under a lvariable pressure, is delivered from the supply connection 47 through the passage 18 and the pipe 17 to the ports 29, the end of the'pipe 17 being chamfered to render the full area of the fuel ports effective. The straight fuel passages and avoidance of pockets therein will minimize the pressure drop and the deposit of material in' the fuel passages. Steam, preferably at a pressure from 70 to 100 lbs. per sq. in. higher than the liquid fuel pressure, is delivered from the supply connection 46 through the passage 16 and barrel 12 to the ports 22 and annular recess 21 from which the steam. is distributed to the steam ports 27 and annular chamber 26. The use of the annular port connecting recesses 2l and 26 insures an adequate supply of steam and substantially uniform distribution thereof to all of the steam discharge slots 30, with only a relatively low steam pressure drop through the burner.' The liquid fuel during its passage tothe point of atomization is thus surrounded by the atomizing fluid. This is particularly advantageous with low grade fuels as the discharge head of the burner is normally exposed to the radiant heat of the furnace and the high temperatures to which the discharge head would normally be heated tend to cause cracking of the liquidfuel and carbon deposits in the passages 29. By the present arrangement, the burner parts between the furnace and the passages 29 are continuously cooled by the steam and carbon deposits therein minimized.

The described arrangement of the steam discharge slots and fuel ports relative to the mixing chamber 28 has been found to be particularly effective in attainingthe desired flame conditions. As the jet of fuel issues from each port 29, it is immediately. swept up by the corresponding high velocity blast of steam cutting directly across the end of the fuel port. The force of the expanding steam effects a complete atomzation of the issuing fuel. The several streams of the fuel and steam mixture entering the mixing chamber 28 at circumferentially spaced points have`a whirling movement in the same direction about the periphery of the mixing chamber, insuring an intimate mixture of all of the fuel and steam particles. The whirlingmass f steam and fuel particles passes out through the nozzle with practically no pressure drop therein in a conical spray having a spray angle normally less than 90".

I have found that with a single sprayer plate and nozzle constructed and arranged as described,

excellent atomization of 5 Baume oil could be forming an unrestricted continuation obtained for all capacities from 500 to 3500 lbs. of oil per hour, the flame 'at all c'apacities being short, bright and\sparkless. 'I'he changes in capacity wereeffected by varying the steam and liquid fuel pressures, the pressure differential between the steam and fuel being maintained within the rangev noted heretofore. With a lesser pressure differential, sparking ,tends to occur, indi-y cating incomplete atomiza'tion, and with a greater differential, theame tends to be blown away t from the burner tip. No smoky or cloudy condi,-

tion in the ame was observed, indicating that the fuel was not being blanketed by the steam and thus kept from. freely combining with `the combustion supporting air.

Substantially the same results were obtained with the modified form of sprayer plate illustrated in Fig; 6. That construction is identical with the sprayer plate construction heretofore described, except that the steam discharge slotsA in Fig'. 6 have a 'if'v taper towards their discharge ends to somewhat reduce the steam pressure drop throughthe slots. v.

.While in accordance with the provisions of the statutes I have illustrated and` described herein the best forms of my. invention now known to me, those skilled in the art will understand that changes may be made in the form of the liquid fuel burner ,disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may some-- times be used to advantage without a corresponding use .of other features. l

1. A steam atomizing liquid fuel -burner com- .prising a liquid fuel conduit, a discharge head at the discharge end of said conduit and including a circular mixing chamber, a series 'of ports connecting said liquid fuel conduit and said mixing chamber and having their -centers symmetrically spaced on the circumference of said mixing chamber, a series' of steam discharge slots terminating adjacent the bottom of -said mixing chamber, each of said slots terminating adjacent 'to the periphery of one of said ports and arranged to provide a steam discharge across said port into said mixing chamber, and a discharge passage of said mixing chamber.

2. A. steam atomizing liquid fuel burner comprising a liquidfuel conduit, a discharge head at the'discharge end of said conduit and including a circular mixing chamber. a series of vports connecting said liquid fuel conduit and said mixing ch'amber and having their centers symmetrically spaced on the circumference of said mixing chamber, a series of steam "discharge slots, each 'of said slots terminating adjacent to the periphery of one of said ports and angularly arranged relative to the circumference of said mixing chamber sufficiently 'to provide .a discharge' across said port and within and adjacent to the circumference of lsaid mixing chamber, .and a discharge passage forming an unrestricted continuation of said mixing chamber.

3'. A steam atomizing liquid fuel burner comprising an axial liquid fuel supply conduit, a concentric steam supply conduit, a discharge head at the discharge end of said conduits and in-.

cluding a circular mixingchamber centrally .thereofja series of ports connecting said liquid fuel conduit and mixing chamber and having their lcenters symmetrically spacedon the circumference of said mixing chamber, a'series of steam discharge slots connected to said steam prising a liquid fuel l.supply conduit extending axialy of said burner', asteam supply conduit conduit, each of said slots terminating adjacent the periphery of one ofsaid ports and angularlyy arranged relative to the circumference of said mixing chamber sufficiently to provide adischarge across said port and within afnd adjacent to the circumference of said mixing chamber, and an axial haring discharge passage forming an unrestricted continuation of said mixing chamber` 4. A steam atomizing liquid fuel lburner comprising a liquid fuel supply conduit extending axially of said burner, a steam supply conduit, a separable sprayer plate at the discharge end of said conduits and having a central circular 90 mixing chamber, a series of ports connecting said liquid fuel conduit and said mixing chamber-and symmetrically spaced about the circumference of said mixing chamber, a series of-.steam discharge slots in the forwardl face of said sprayer p ate, each of said slots terminating adjacent to the periphery of one of said ports and arranged to provide a steam discharge across said port intov said mixing chamber, and a nozzle contacting ence of said mixing chamber, a series of steam discharge slots in the forward face of said sprayer plate, each of said slots terminating adjacent to the periphery ofcne of said ports and angularly arranged relative to the circumference of said 1 mixing chamber sufliciently to provide a steam discharge across said port and within and. adjacent to the-circumference of said mixing chamber,` and a nozzle contacting with the forward face of said sprayer plate and having an axial 1 discharge passage forming an unrestricted continuation of said mixing chamber.

6. A steam atomizing liquid fuel burner corn--l surrounding said liquid fuel conduit, a sprayer plate at the discharge end of said conduits and having an outer'series' of ports'opening into said steam conduit, a central circular mixing chamber, an inner series .of ports 'connecting said liquid fuel conduit and. said mixing chamber and hav-- ing' their vcenters symmetrically spaced on the circumference of said mixing chamber, a lseries of steam discharge slots extending between said inner and outer series of ports, .eachof said' slots 1 extending from the periphery of one of said inner ports to lan outer -port angularly spaced- 4therefrom 'suihciently to provide '.a steam discharge across said inner port and within and adjacent' tothe circumference of said mixing chamber, and a nozzle contacting with the forward face of saidsprayer plate and having an axial discharge passage forming an unrestricted conl tinuation of said mixing chamber.

7. A steam atomizing liquid fuel burner com- 1 -prising a liquid-fuel supply conduit extending axially of sald'burner, a steam supply conduit surrounding said liquid fuel conduit, a sprayer platel *at ,the discharge end of said conduits and having an outer series of ports opening into 1 cent to vthe circumference of said-mixing chamber, and a nozzle contacting with the forward face of said sprayer plate and having an axial discharge passage with a rear portion forming an unrestricted continuation of said mixing chamber and a forward flaring portion.

8. A steam atomizing liquid fuel burner comprising a liquid fuel supply conduit extendingA axially of said burner. a steam supply conduit surrounding said liquid fuel conduit, a sprayer head mounted on-the inner end of said steam conduit and having a series of ports opening into said steam conduit. a sprayer. plate at the inner end of said sprayer head and having an outer series of ports'receiving steam from said sprayer.

head ports, a, central circular mixing chamber, an inner series of ports connecting said liquid fuel conduit and said mixing chamber and having their centers symmetrically spaced on the circumference of said mixing chamber, a series of steam discharge slots in the forward face of said sprayer plate and extending between said inner and outer series of ports. each of said slots extending from the periphery of one of said inprising a -ing a central ner ports to an outer -port angularly spaced therefrom sufficiently to provide a' steam discharge across said inner port and within and adjacent to the circumference of said mixing chamber, a nozzle contacting with the forward face of said sprayer plate and, having'an axial discharge passage with a rear portion -forming an unrestricted continuation of said mixing chamber and a forward haring portion, and a ,cap member removably mounted on said sprayer head and holding said sprayer plate and nozzle in position.

9. A sprayer plate for liquid fuel burners havcircular mixing chamber formed therein. a series of ports symmetricallyrspaced about the circumference of said chamber, and a plurality of4 discharge slots formed therein, each f of said slots extending substantially transversely tooneof said ports to provide a discharge dlrectly across said port. i

`10. A sprayer plate Vfor liquid hiel burners corneounterbored portion forming a central circular mixing chamber in one face thereof, ai series of ports symmetrically spacedabout the circumference of said chamber, andI a plurality of dischargeslots formed therein,- each of said slots extending'- from the periphery' of. one -of sa'id ports and arranged to provide a discharge therefrom across said port and within .the circumference of said mixing chamber.

11. A sprayer plate for liquid fuel burners comprising avcounterbored portion forming a centrai circular mixing chamber in one face thereof. a series of ports having their centers symmetrically spaced on' the circumference yof said chamber. and a plurality of discharge slots formed in the mixing chamber face, each of said slots extending from the periphery of one of said ports and angularly arranged relative to the circumference of said chamber sufficiently to provide -said annular recess, each of a discharge therefrom across said port within and adjacent to the circumference of said mixing chamber.

12. A sprayer plate for liquid fuel burners comprising a counterbored portion forming a central circular mixing chamber in one face thereof, an inner series of ports having their centers symmetrically spaced on the circumference of said chamber, an outer series of ports concentric with said inner series, and a plurality of discharge slots formed in the mixing chamber face of said plate and extending between said inner and outer series'of ports, cach of said slots extending from the periphery of one of said innerports to one of said outer ports.

13. A sprayer plate for liquid fuel burners comprising a counterbored portion forming a centrai-'circular mixing chamber in one face thereof, an inner series of ports having their centers symmetrically spaced on the circumference of said chamber,- an outer series of ports concentric with said inner series, and a plurality of discharge slots formed in the mixing chamber face of said plate and extending between said inner and outer series of ports, each of said slots extending from the periphery of -one of said inner ports -to an outer port angularly spaced therefrom sufficiently to provide a discharge therefrom across said inner port and within and adjacent to the circumference of said mixing chamber.

14. A sprayer plate for liquid fuel burners comprising a counterbored portion forming a central circular mixing chamber in one face thereof, a series' of ports having their centers symmetrically spaced'on the circumference of nu saidchamber, an annular recess formed on said l face and surrounding said series' of ports, and a plurality of discharge slots formed in said face and extending between said series of ports and from the periphery oi' one of said inner ports`to-4 sai'd recess and angularly arranged relative to said circumference sufficiently to-provide a discharge therefrom across said port and within and said slots extending adjacent to the circumference 'of said mixing 120 chamber.

15. A sprayer plate for liquid fuel burners comprising a counterbored portion forming a central circular mixing chamber in fone facethereof, an inner series of ports having their centers symmetrically spaced on the circumference of said chamber, an outer series of ports concentric with said inner series. and a plurality of discharge slots of inwardly decreasing cross-sectional area ber face of said plate and extending between said inner and outer series of ports, each of 'said slots extending from the periphery'of one of said,

innerports to an outer port angularly spaced therefrom sufliciently to provide a discharge therefromacross said inner port and within and adjacent to the circumference of "said mixing chamber. p

16." A steam atomizing liquid fuel burner comprising a discharge head having a discharge opening and a mixing chamber of substantially circular discharge opening. a' series of liquid fuel ports opening through the bottom of said mixing chamber at points symmetrically spaced relative and adjacent to the circumferential wall of said mixing chamber, a series of discharge slots symmetrically arranged relative to said mixing chamber and having their dischargeends openformed in the mixing chamcross-section communicating with said' las ing thereto in 'substantially the plane of said 15g fuel under pressure to said liquid fuel ports,

mixing chamber bottom, each slot being arranged substantially tangential to said mixing chamber and terminating adjacent to and directed across the discharge end of a correspondy 5 ing fuel port, means for supplying a liquid fuel under pressure to said liquid fuel ports, and means for supplying steam ata substantially higher pressure than said liquid fuel to said discharge slots.

1'1. A steam atomizing liquid fuel burner comcharge opening and a central mixing chamber of substantially circular cross-section communicating with and symmetrically arranged relative to said discharge opening, a series 4of liquid fuel ports opening through the bottom of said mixing chamber at points symmetrically spaced relative and adjacent to the circumferential wall of said mixing chamber, a series of discharge slots symmetrically arranged relative to the circumference of said mixing chamber and having theirdischarge ends opening through the circumferential wall of said mixing chamber with the bottoms of said slots arranged in substantially the plane of said mixing chamber bottom, each slot being arranged substantially tangential to said mixing chamber and terminating adjacent to and directed across the discharge ends of a corresponding fuel port, means for supplying a liquid and means forA supplying steam at VaA substantially higher pressure than said liquid fuel to said discharge slots. I a

' ing chamber ywith 18. A sprayer plate for liquid fuel burners having formed therein a central chamber of substantially circular cross-section, a series of liquid fuel ports opening through the bottom of said chamber at points adjacent to the circumferential wall of said chamber, and a series of discharge slots arranged about the circumfer each slot being arranged to said chamber and mixing chamber face and symmetrically arranged about the circumference of said mixing chamber and having their discharge ends opening through the circumferential wall of said mixthe bottoms of saidslots ar, ranged in substantially the plane of said mixing chamber bottom, each slot being arranged substantially tangential to said mixing chamber and terminating adjacent to and directed across the discharge end of a corresponding fuel port.

i JAMES FLETCHER.

CERTIFICATE 0F CORRECTION.

Paget: No. 1, 98o, 132.

` November 6, l1934;l

JAMES FLETCHER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as'fol'low's:

line 47, strike out the word "inner-3';

Page 2, first column,

and in lhe same line, after "forward" l tions therein that the same may conform to th I e record f Signed and sealed this 19th day of March, A. D. N35-the case m the Patent Ofhce.

(Seal) h i LeslieFrazer Acting .Commissioner of Patents.

in substantially the plane' fuel under pressure to said liquid fuel ports,