US2932347A - Burner apparatus - Google Patents

Description

April 1960 I K. s. JAEGER 2,932,347

BURNER APPARATUS Filed April 24, 1956 3 Sheets-Sheet l a Flml- INVENTOR.

Y KURT S. JAEGER Fl E. B

ATToRue'v P 1960 K. s. JAEGER 2,932,347

BURNER APPARATUS Filed April 24, 1956 3 Sheets-Sheet 2 IN V ENTOR.

KURT S. JAEGER BY AT roiiuev 7 April 12, 1960 K. s. JAEGER BURNER APPARATUS Filed April 24, 1956 3 Sheets-Sheet 3 {NVENTOR BY KURT S.JAEGER 2,932,347 BURNER APPARATUS Kurt S. Jaeger, Tulsa, Okla, assignor, by jmesne assign ments, to Midland-Ross Corporation, Cleveland, Ohio, a corporation of Ohio Application April 24, l956,'Serial No. sso,s07

' 4 Claims. (c1. 158-11) This invention pertains to an improved fuel burner and more specifically to a burner capable of individually burning two fuels for use in boilers or the like.

I Dual fuel burners are well knowri in the art, particularly those burners separately firing both oil and gas. There are several important aspects connected with the operation of this type of burner: both fuels must be burned efliciently; flame stability must be attained; the

oil nozzles must be kept relatively cool to .prevent coking For further consideration of what is novel and the invention, refer to the following specification, claims, and,

accompanying drawing.

In the drawing:

Figure 1 is a partially sectional, elevation view of a burner embodying the invention,

Figure 2 is a partially sectional, front view of the burner of Figure 1,

Figure 3 is a cross-sectional detailed view of a portion of Figure 1, r

Figure 4 is a partially sectional, front view of the apparatus of Figure 3, s Figure 5 is a cross-sectional elevation view .showing the shape of the burner flame when burning gas,

Figure 6 is a front view of the gas flame pattern, .and Figure 7 is a detailed view of an alternate form of a portion of the apparatus of Figure 3.

Referring to the drawing, and more particularly to Figures 1 and 2, burner 11 comprises an outer casing 12,.a

blower' housing 13, a blower 14, a removable section 15 of housing 13, and a gas manifold 16. Section 15 permits oil lines 17, oil nozzles 18, pilot gas line 20, pilot burner 21, ignition electrodes' 22, flame electrode 23, and inner casing 24, forming an inner passage 43, to be 2,932,347 Patented Apr. 12, 1960 a single larger port were located in the center of the passage between adjacent vanes. The ports 28 are preferably formed by aluminum tubes, aflixed to. gas lines 30, that are cn'mped to form the two ports. Q'However, they may also be drilled in conventional spuds. The

- nozzles are supplied gas through gas lines 30 from manifold 16, to which gas is supplied by a pipe 31.

Referring more particularly to Figures 3 and 4, a mincated, conical wall 32 is positioned with respect to inner casing 24 so as to form an annular nozzle 33 therewith. This nozzle is arranged to direct a portion of the air in inner passage 43 toward ports 38. A longer, truncated.

conical wall 34 is attached to intermediate casing 25 to form chamber 35 defined by wall 34, intermediate casing 25, and an inwardly projecting wall 36, and has an outlet 37 adjacent the flame retention ring 40. Wall 34 con-' tains ports or holes 38 which admit a small portion of between the casings 12, 2 4, and 25. When only oil fuel is being burned, air passing through passageg 43 serves as primary air, air through passage 44 as secondary air,

and air through passage 45 as tertiary air. Also, when only gas fuel is being burned, air through passage 44- serves as primary air, air through passage 43 assecondary air, and air through passage 45 as tertiary air.

When operating with gas fuel, air from blower 14 and gas from nozzles 27 in passage 44 are spun by vanes 26 and pass outthe downstream end of this passage. Upon reaching the downstream end of inner casing 24, the airgas mixture is met by a diverging stream of secondary air from nozzle 33' and passage 43. This diverging stream, coupled with the whirling effect of vanes 26, tendsto force the mixture outwardly and maintain it in an annular path. -The center of this annular path being air from passage 43, burning is prevented here until the air-gas mixture mixes with this air at a substantial distance downstream from the burner end. The oil nozzles 18 are thereby maintained well away from the flame and stay relatively cool. This is essential to prevent the oil nozzles from coking and thus becoming plugged, which will occur if they become too hot. Furthermore, the fiame will not burn down in the head of the burner, a common fault that seriously shortens the life of such.

Toward the downstream end of intermediate casing 25,

i a small portion of the rich air-gas mixture in passage easily removed as a unit for'replacernent or repair. Ignii tion electrodes 22 and flame electrode 23 are encompassed in ceramic 19 which are, with oil lines 17 and pilot gas line 20, supported within casing 24'by harnesses 29. The inner casing 24 is axially aligned with outer casing 12, and an intermediate casing 25, which is axially aligned with the aforementioned casings, forms apassage' 44 between the intermediate casing 25 and the inner casing 24, and also a passage 45 between the intermediate casing 25 and the outer casing 12. In passage 44 are vanes 26 and gas nozzles 27. These nozzles actually contain two ports 28, each of which is adapted to emit gas on either side of the. corresponding vane 26 with which it is aligned. This affords a greater uniformity inEgas distribution than would otherwise be attained if 44 and additional air from nozzle 33 euterports 38 into chamber 35. Here they mix and flow at relatively low velocity past retaining ring 40 and at this point mix with more of the air emitted from nozzle 33. The new mixture then ignites readily from the pilot flame. of gas pilot 21 and forms the base of the burner flame on retaining ring 44 The flame, when gas is burned, tenaciously clings to this ring and produces a very stable quiet operation. Without such an arrangement the base of the flame will constantly fluctuate which produces a loud, disagreeable noise. Such a burner may be audible for a distance of several city blocks or if placed in a boiler room, it will render adjacent rooms uninhabitable. It is not certain that the aforementioned co-action between the air emitted from nozzle 33 and the mixture in chamber 35 is exactly correct. However, if the casing 24'is extended so that nozzle 33 is directed substantially 'downstream'of' ports 38, the burner will not properly function when gas is burned. 5';

The flame, upon emission from the burner, must not diverge too rapidly or blow-off will occur. Thus, the

teritary air from nozzle 41 may be directed inwardly in a converging manner to. counteract the spreading. tendency of the spinning fmixture from'passage 44 for a short dist ance downstream of ring 40, The air through the passages 44 and 45 must be apportioned so as to maintain the direction of the base portion of the. flame between a con verging angle of 10 and a diverging angle of 20 to the axis of the burner in order to prevent blow-off. The apportionment is also dependent on the angle of vanes 26. A flame whose base portion travels in a direction outside these limits will not be maintained on the ring 40 with noisy, unsteady burning resulting.

The tertiary air from passage 45 also serves to support additional combustion primarily in the area adjacent retaining ring 40. As the flame propagates further from ring 40, the secondary air from passage 43 serves as additional combustion air to support additional burning, the air supplied through passage 44 being insuificient to sustain complete combustion.

The gas flame has a shape as shown in Figures and 6 with a hollow center and the base at the retaining ring, as previously mentioned. It spreads in a conical manner, traveling in a spreading helical path shortly after leaving the burner, being prevented from immediately diverging due to the inward direction of air from nozzle 41. The representation of Figure 5 is used to show the concentration of the burning gases and does not indicate the spinning effect. This rapidly spreading flame, which is caused by the whirling of the air-gas mixture created by vanes 26, is especially advantageous for boiler applications where the burner is placed in a fire box represented by walls 61. The spreading flame causes heating of a large portion of the fire box adjacent the burner that is untouched by other burners with their long, narrow flame emission. Thus the usual result for fire box applications is to overheat the far end of the box while leaving the closer end relatively cool. The subject burner heats the box more uniformly and thereby affords more effective use of it.

In an alternate method, of construction as shown in Figure 7, a series of ports 51 are formed in intermediate casing 25 to afford an access from passage 45 to volume 35. Scoops 52 may be included to direct air from passage 45 into volume 35, the air mixing with the rich'air-gas mixture therein emitted through ports 38 from passage 44. The scoop may be formed by afiixing a metal ring to the outer surface of intermediate casing 25 at the downstream edges of ports 51 or may be formed by extending outwardly the metal that is displaced from the ports, this metal still forming an integral part of the casing at the downstream edges of them. With this apparatus, the wall 32 may be eliminated since the additional air required to form areadily combustible mixture in volume 35 is now suppliedrfrom passage 45.

When oil is used for firing, it is atomized by nozzles 18 and mixed with primary air in passage 43. The airoil mixture is ignited by gas pilot 21 which is used for the ignition of both gas and oil. The flame produced by this mixture is not maintained on the retaining ring as the gas flame is, but burns in a relatively steady flame about six inches away therefrom. There is no appreciable acoustic problem with the oil flame in spite of the fact it is not firmly retained by a ring or the like. This is due to the combustion characteristics of oil which produce an inherently relatively stable flame front as compared to that of gas.

The pilot burner 21 is ignited by conventional electric ignition electrodes 22 which are spaced slightly apart in front of pilot burner 21 and form an arc therebetween when current isapplied. Flame electrode 23 is connected with a commercially available electronic unit for shutting off the supply of fuel should. the pilot flame become extinguished.

The apparatus described herein is the best mode known to the inventor of carrying out the invention, the scope of which is limited only by the appended claims.

I claim:

1. A fuel burner comprising: an outer cylindrical casing; an inner cylindrical casing coaxial with said outer casing and forming a first passage; an intermediate cylindrical casing coaxial with said inner casing and forming a second passage between said intermediate casing and said inner casing, and a third passage between said intermediate casing and said outer casing; a plurality of gas nozzles equally spaced in said second passage; means for supplying gas to said nozzles; supply means for fursecond, and third passages; a flame retention ring located adjacent the downstream end of said outer casing for retaining thereon the base of the flame resulting from an ignited mixture of the gas and nishing air to said first,

, air; wall means forming an annular chamber with the inner surface of the downstream end of said intermediate casing and a plurality of ports in said wall means to admit gas and air from said second passage to said chamber, said chamber having an outlet adjacent said flame retention ring; and means for directing additional air toward said chamber for supply thereto.

2. A fuel burner for boilers and the like comprising an outer casing; an inner casing coaxial with said outer casing, located within said outer casing, and forming a first passage, the downstream end of said inner casing terminating substantially upstream of the downstream end of said outer casing; a first truncated, tapered wall coaxial with said inner casing, said wall being spaced from the downstream end of said inner casing to form a first nozzle "therewith; an intermediate casing located between said inner and said outer casings and coaxial there-' with, the downstream end of said intermediate casing terminating downstream of the downstream end of said inner casing, said intermediate casing forming second and third passages between said intermediate casing and said inner casing and between said intermediate casing and said outer casing respectively, said second passage having a cross-sectional area substantially larger than the crosssectional area of said third passage; a flame retention frame coaxial with said intermediate casing, being smaller than said intermediate casing, and including means and forming a second nozzle with said outer casing for directing air from said third passage in a convergent, downstream direction; a plurality of fuel nozzles spaced around said second passage; means for supplying fuel to said fuel nozzles; means for supplying air to the upstream ends of said first, second, and third passages; a second truncated wall attached to the inner surface of said intermediate casing and tapering in a downstream direction to form a chamber with said intermediate casing and said flame retention frame, the downstream end of said second wall terminating upstream of said flame retention frame, said second wall containing a plurality of ports through which a portion of the fuel and air in said second passage can flow into said chamber, said first nozzle being upstream of said ports and being directed toward said ports to direct air from said first passage toward said ports; and ignition means located in said first passage for igniting an air-fuel mixture, whereby the portion of the air and fuel entering said chamber will slow down and be ignited adjacent said flame retention frame and the air flowing through said first passage will push out the central portion of the flame front and maintain it substantially downstream of the end of said outer casing and said .flame retention frame.

3. A .burner according to claim 2 and a plurality of vines in said second passage downstream of said fuel nozzles for whirling the air-fuel mixture passing thereby.

4. A fuel burner for boilers and the like comprising an outer casing; an inner casing coaxial with said outer casing, located within said outer casing, and forming a first. passage; :a first truncated, tapered wall coaxial with 5 said inner casing, said wall being spaced from the downstream end of said inner casing to form a first nozzle therewith; an intermediate casing located between said inner and said outer casings and coaxial therewith, said intermediate casing forming second and third passages between said intermediate casing and said inner casing and between said intermediate casing and said outer casing respectively, said second passage having a cross sectional area substantially larger than. the cross-sectional area of said third passage; a flame retention frame near the end of said intermediate casing, and forming a Second nozzle with said outer casing; a plurality of gas nozzles spaced around said second passage; means for supplying gas to said gas nozzles; means for supplying air to the upstream ends of said first, second, and third passages; a second truncated wall attached to ,the inner surface of said intermediate casing and tapering in a downstream direction to form a chamber near said flame retention frame, said second Wall containing a plurality of ports through which a portion of the fuel and air in said second passage can flow into said chamber, said first nozzle being upstream of said ports and being directed toward said ports to direct air from said first passage toward said ports; at least one oil nozzle located cen trally of said first passage and wholly upstream of the downstream end thereof; and ignition means for igniting an air-fuel mixture, whereby the air flowing through said first passage will push out the central portion of the flame front established by the ignited fuel and maintain it substantially downstream of the end of said oil nozzle.

References Cited in the file of this patent UNITED STATES PATENTS 1,321,996 vDreifein Nov. 18, 1919 1,510,039 Canfield Sept. 30, 1924 1,599,412 Goldstone Sept. 14, 1926 1,754,603 Brown Apr. 15, 1930 1,875,394 Richford Sept. 6, 1932 1,925,183 Forster Sept. 5, 1933 2,333,531 Ferguson Nov. 2, 1943 2,368,490 Patterson Jan. 30, 1945 2,377,497 Hopkins June 5, 1945 2,497,321 Pattinson Feb. 14, 1950 2,591,626 Sloan Apr. 11, 1952 2,744,568 Johnson May 8, 1956 2,767,784 Dean Oct. 23, 1956 2,803,296 Young Aug. 20, 1957

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