US 3597141 A
Description (OCR text may contain errors)
United States Patent  Inventors Aribert Fracke Erlangen; Eduard Weber, Nurnberg, both of, Germany [21 Appl. No. 847,642  Filed Aug. 5, 1969  Patented Aug.3. 1971  Assignee Siemens Aktiengasellschait Berlin, Germany  Priority Aug. 7, 1968 [33) Germany  P1751839.7
 BURNER DEVICE FOR FLUIDIC FUELS 10 Claims, 4 Drawing Figs.
 U.S. Cl 431/173, 110/28 F, 431/351, 431/353  Int. Cl. F23c 5/18  Field oISearch 431/9, 158, 353,173, 351, 352; 110/28  References Cited UNITED STATES PATENTS 1,918,397 7/1933 Jezler 110/28 X 2,039,890 5/1936 Coster r. 1 10/104 2,800,093 7/1957 Burg 431/173 X 3,074,470 l/l963 De Piolenc et al 431/158 Primary Examiner- Edward G. Favors AtmmeysCurt M. Avery, Arthur E. Wilfond, Herbert L.
Lerner and Daniel]. Tick ABSTRACT: A burner device for gaseous, liquid or pulverulent fuel comprises a tubular burner structure of a rotationally symmetrical, for example conical or parabolic shape, which tapers from the burner outlet opening toward the much smaller fuel inlet opening. Nozzles for supplying combustion air communicate with the interior of the tapering burner structure in substantially tangential directions respectively and in a plurality of respective planes which extend transversely to the burner axis and are axially spaced from each other. Preferably a cylindrical combustion chamber structure is coaxially joined with the tubular burner structure at the outlet opening of the latter and is provided with additional combustion-air supply nozzles which are directed tangentially toward the interior of the combustion chamber. Roughness structures are preferably mounted on the interior wall of the tapering burner structure and may be adjustable as to the height up to which they protrude into the interior of the burner.
BURNER DEVICE FOR FLUIDIC FUELS Our invention relates to burner devices for fluidic, i.e. gaseous, liquid or pulverulent fuels, and more particularly to burner devices having an axial fuel supply inlet and an axial gas outlet located opposite the fuel inlet.
There are known burner devices with combustion chambers operating on the cyclone principle and having means for supplying the fuel through the combustion chamber jacket in axial or tangential directions; and it is also known to supply the combustion air tangentially into generally cylindrical combustion chambers. With such cyclone-type devices, however, a complete combustion of the fuel substances is not always secured. This deficiency is due to the fact that the gas flow along the inner wall surface of the burner in the downward direction toward the bottom may result in the formation of suspended rings of fuel substance near the bottom of the combustion chamber and that the fuel substance held floating in such rings becomes combusted to an only poor degree, thus impairing the combustion performance.
It is an object of our invention to devise a burner device that secures a complete combustion of the fluid or fluidized fuel substances; and it is another object of the invention to design the burner device in such a manner as to permit controlling or regulating the combustion performance within wide limits.
According to the invention, we give the burner structure in a burner device generally of the type mentioned above, a circularly symmetrical, namely an approximately conical or substantially parabolic shape which tapers from the relatively wide outlet opening of the tubular structure toward the narrow coaxial fuel inlet end, this tapering burner structure being provided with nozzles for supplying combustion air, which nozzles have respective injecting directions substantially tangential to the burner interior wall surface in mutually spaced planes transverse to the burner axis.
By virtue of the conical or parabolic shape of the tubular burner, the objectionable formation ofa fuel ring in the vicinity of the bottom or fuel inlet region is avoided since the tapering design causes the combustion air to travel along the inner wall surface of the tubular burner from the interior in an outward direction. Furthermore, a stoichiometric combustion and a good controllability of the energy throughput and of the flame character is attained in such a manner that by varying the supply of combustion air, a performance at any desired point over the entire ranges between radiating and nonradiating flame can be obtained.
According to another feature of the invention, a cylindrical combustion chamber is preferably joined with the outlet end of the conical or tapering burner, and the cylindrical chamber is provided with additional nozzles for the supply of combustion air, these additional nozzles having an injecting direction tangential to the chamber and preferably inclined toward the main flow direction of the tubular burner. This af fords considerably shortening the effective length of the burner.
According to still another feature of the invention, the interior wall of the burner may be provided with roughness structures between the combustion-air nozzles. This secures a combustion with a smaller share ofradiation in the flame.
The invention will be further described with reference to embodiments illustrated by way of example on the accompanying drawing, in which:
FIG. I shows schematically a lateral view onto a burner device according to the invention having a conically tapering burner portion;
FIG. 2 shows schematically a cross section through the same burner along the line lI-II in FIG. 1;
FIG. 3 is a sectional view of part of a burner having an approximately parabolic shape, and also shows diagrammatically the course of the gas flow in the burner;
FIG. 4 shows partly in section a detail of the burner device according to FIGS. 1 and 2.
The conical burner 1 (FIGS. 1, 2) or the parabolic burner 1' (FIG. 3) of the illustrated devices is provided with an axial fuel inlet duct 2 adjoining the narrowest end of the tubular tapering shape. Several rows of nozzles 3 to 6 are arranged in tangential relation to the burner-tube jacket in respective planes perpendicular to the axis of the burner device, four such planes being shown for example. Two or more such nozzles may be provided in each of the respective planes, although only two such nozzles are illustrated in each plane. The conically tapering burner l proper is joined with a cylindrical combustion chamber structure 7. This chamber structure has the same diameter as the outlet opening of the tapering burner l and is provided with further nozzles 8 for combustion air. The nozzles 8 extend substantially in tangential directions with respect to the cylindrical combustion chamber 7 and are inclined toward the fuel inlet and consequently toward the main flow direction of the burner device.
As schematically exemplified by the drawing, the total cross-sectional area of the fuel inlet in a device according to the invention is preferably of a lower decimal order of magnitude than'the cross-sectional area of the outlet opening and of the adjacent combustion chamber 7. For example, the ratio of these two areas in the illustrated example is between 25 and 30. That is, the diameter of the fuel inlet end is less than onefifth of the outlet diameter.
Bulge-shaped roughness structures 9 are mounted on the interior wall of the burner 1 between the orifices of the respective nozzle rows. The roughness structures are shown to have a straight shape, although they may be curved or be given the shape of a spiral. The nozzle orifices preferably are flush with the inner wall surfaces of the tubular burner l and the combustion chamber 7 so that the roughness structures 9 constitute substantially the only obstacles in the flow path of the gases.
FIG. 3 illustrates diagrammatically the course of the com bustion gases inside the tapering burner structure 1 which in this case is approximately parabolical, although the same phenomena occur in a straight cylindrical taper. It is surprising that in such a device, contrary to the known cylindrical cyclone-type combustion chambers, the airflow in the region near the wall does not pass from above downwardly and thence along the innermost, axial region upwardly to the gas outlet. On the contrary, as shown in FIG. 3, the travel course of the combustion gases is just the reverse. As a consequence, the combustion gases travel in the region close to the inner surface from the fuel inlet 2 in an outwarddirection. Due to a recirculation at the end of the burner, which recirculation can be controlled by the above-mentioned roughness means, the air then partially flows toward the axis of the burner and thence inwardly in the direction toward the fuel supply inlet 2.
Of the illustrated air nozzles 4, 5 and 6, the uppermost nozzle 4, according to FIG. 3, is closed. This has the effect that the core 10 of the flame is displaced downwardly in the direction toward the fuel inlet 2. In addition, the nozzles can be supplied with controlled, respectively different quantities of air, and the roughness structures 9 can be displaced to respectively different positions with the combined effect of thereby controlling the recirculation of air so as to attain a good flame stability. By varying the supply of fuel to the fuel injection nozzles in inlet 2, a narrower or wider fuel cone can be adjusted as is indicated, for example, by the lines 11 and 12 in FIG. 3. By proper adjustment, the fuel is directed into the flame core 10.
Due to the tangential injection of the combustion air, a good mixing of air and fuel is secured. Since, further, the distribution of the nozzles over the entire axial length of the burner structure 1 or 1' results in continuously subjecting the jacket surface of the burner to fresh air, the tapering jacket structure remains relatively cool: Combustion occurs with a stable flame essentially in proximity to the combustion chamber wall. Furthermore, by varying the supply of air through the individual nozzles, a predominantly radiating or nonradiating flame can be obtained, as may be desired.
The above-mentioned roughness means on the inner wall surface of the burner structure and the resulting control effect upon the recirculation of the combustion air, also permit reducing the share of radiation in the flame. By providing for variable adjustment of the roughness structures, namely by setting them to protrude more or less deeply into the burner space, the device can be operated with a substantially radiating or nonradiating flame, depending upon the protruding height of the roughness structures.
An embodiment of a roughness structure 9 adjustable in the just-mentioned manner is shown in FIG. 4 with reference to the device according to FIGS. 1 and 2. The roughness structure 9 has a bulging shape and is mounted on a traverse bar 13 whose respective ends are seated on bolts 14 securely fastened to the sheet metal jacket of the conical burner 1. Helical pressure springs 15 and screw nuts 16 permit setting the roughness structure 9 so as to more or less protrude through an opening into the interior of the burner I.
To those skilled in the art it will be obvious, upon a study of this disclosure, that our invention permits of various modifications and may be given embodiments other than particularly illustrated and described herein, without departing from the essential features set forth in the claims annexed hereto.
1. A burner device for gaseous, liquid or pulverulent fuel comprising a tubular burner structure having a gas outlet opening and a fuel inlet opening at coaxially opposite ends, said fuel inlet opening having a smaller diameter than said outlet opening and defining a path coaxial to said tubular burner structure for supplying a nonturbulent flow of fuel to said tubular burner structure, said tubular structure having a rotationally symmetrical shape tapering from said outlet opening toward said inlet opening, and a plurality of nozzles supplying combustion air communicating with the interior of said taper ing burner structure in substantially tangential directions respectively and disposed in a plurality of respective planes which extend perpendicularly to the burner axis and are axially spaced from each other, said nozzles being throttleable individually as well as in groups.
2. In a burner device according to claim 1, said tubular said tubular burner structure at said outlet opening and having an inner diameter substantially equal to that of said outlet opening.
5. In a burner device according to claim 4, said diameter of said outlet opening being more than five times the diameter of said fuel inlet.
6. In a burner device according to claim 4, said chamber structure having further substantially tangential nozzles for supply of additional combustion air.
7. In a burner device according to claim 6, said further nozzles being directed at an inclination toward the fuel inflow direction of said fuel inlet.
8. In a burner device according to claim 1, said nozzles having their respective nozzle orifices located substantially at the interior surface of said tapering tubular burner so as to leave the interior of said burner substantially unobstructed.
9. A burner device for gaseous, liquid or pulvcrulent fuel comprising a tubular burner structure having a gas outlet opening and a fuel inlet opening at coaxially opposite ends, said fuel inlet opening having a smaller diameter than said outlet opening, said tubular structure having a rotationally symmetrical shape tapering from said outlet opening toward said inlet opening and nozzle means for supplying combustion air communicating with the interior of said tapering burner structure in substantially tangential directions respectively and in a plurality of respective planes which extend transversely to the burner axis and are axially spaced from each other, said tubular burner structure com rising roughness structures located on its interior surface etween said nozzle orifices and protruding into the interior of said tubular burner structure.
10. A burner device for gaseous, liquid or pulverulent fuel comprising a tubular burner structure having a gas outlet opening and a fuel inlet opening at coaxially opposite ends, said fuel inlet opening having a smaller diameter than said outlet opening, said tubular structure having a rotationally symmetrical shape tapering from said outlet opening toward said inlet opening and nozzle means for supplying combustion air communicating with the interior of said tapering burner structure in substantially tangential directions respectively and in a plurality of respective planes which extend transversely to the I burner axis and are axially spaced from each other, said tubu-