US 3227201 A
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Description (OCR text may contain errors)
L. Z. POKORN Y Jan. 4, 1966 GAS BURNER 2 Sheets-Sheet 1.
Filed Oct. 17, 1963 INVENTOR. POKORN Y ZZZZZZ:
A TTORNE V Jan. 4, 1966 L. z. POKORNY 3,227,201
GAS BURNER Filed Oct. 17, 1963 2 Sheets-Sheet 2 INVENTOR LASZLO z. POKORNV A TTORNEV United States Patent 3,227,201 GAS BURNER Laszlo Z. Pokorny, Rochester, N.Y., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Oct. 17, 1963, Ser. No. 316,967
2 Claims. (Cl. 158-7) This invention pertains to gas burners, and particularly to a high efliciency radiant burner designed for use with a pressurized combustible mixture of gaseous fuel and air.
Heretofore, burners have been designed for use in a combustible chamber wherein the combustible mixture is supplied at a pressure greater than the pressure within the combustion chamber. The present invention relates to a pressurized radiating refractory shell which is heated to incandescence, and wherein the fuel mixture is burned externally thereof.
Accordingly, among my objects are the provision of a pressurized radiant gas burner; the further provision of a pressurized radiant gas burner having means for obtaining directional heating effects; and the still further provision of a pressurized radiant gas burner having a refractory shell which is heated to incandescence during burner operation.
The aforementioned and other objects are accomplished in the present invention by utilizing a refractory shell having a tapered configuration of increasing cross-sectional area in a direction extending away from the burner supply nozzle, and wherein the refractory shell has a perforated surface through which the flue gases flow.
Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearly shown and wherein similar reference numerals depict similar parts throughout the several views.
In the drawings:
FIGURE 1 is a fragmentary longitudinal sectional view of the preferred burner embodiment constructed according to the present invention.
FIGURE Z is an enlarged sectional view taken along line 22 of FIGURE 1.
FIGURES 3, 4, 5 and 6 are, respectively, sectional views similar to FIGURE 2 of modified refractory shell constructions.
Referring to FIGURE 1, in the preferred embodiment the pressurized radiant gas burner of this invention is shown in combination with a cylindrical metal combustion chamber 10 having external extended surfaces in the form of fins 12. The interior of the combustion chamber communicates with a flue gas heater 16, which in turn, connects with a plurality of extended surface heat exchangers, as indicated in phantom by numeral 18. The opposite end of the combustion chamber 10 has a refractory insulation shield and a pair of metal brackets 22 and 24 attached thereto for supporting the radiant gas burner.
The gaseous combustible mixture, composed of a suitable premixed gaseous fuel and sufiicient air to effect complete combustion, is supplied under superatmospheric pressure through a pipe 26 supported by the brackets 22 and 24, the juncture between the pipe 26 and the bracket 22 being made gas tight by a refractory seal assembly 28. The end of the pipe 26 has a screen 30 extending thereacross to prevent backflash. A burner nozzle 34 is supported between the bracket 22 and the refractory shell 20, the burner nozzle being of the general type disclosed and claimed in my copending application Serial No. 316,968, filed of even date herewith. Accordingly,
the nozzle 34 has an integral outwardly flared, frustoconical edge 36 which defines an annular chamber'38, conical in section with the lip 40 of the nozzle. The
lip 40 is shown having two circumferential rows of openings 42 spaced inwardly of the edge thereof communicating with the annular chamber 38. Conventional spark type ignition electrodes 44 extend into the nozzle 34 for initially igniting the combustible mixture.
According to the present invention, a shell 46 of suitable refractory material, either refractory ceramic or metal, which can be heated to a high degree of incandescence, is mounted within the combustion shell 10. The shell 46 is formed with an integral elongate solid or hollow conical deflector, or flame spreader, 48 the apex of which is located inwardly of the edge of the nozzle 34. The shell 46 is supported by a rod 50 attached to a pair of spaced brackets 52 within the inlet pipe 26, and is also supported adjacent its inner end by the combustion shell. More particularly, the inner end of the refractory shell 46 has an enlarged rim 54 which is keyed at 545m the shell and has gas tight engagement therewith.
The refractory shell 46, as seen in FIGURE 1, is tapered from its outer end to its inner end, or in other words, is of increasing cross-sectional area from the nozzle 34 towards the header 16. In the preferred embodiment the refractory shell 46 is of circular cross-section and has a distributed set of perforations, or holes 58. The holes 58 are of uniform size, but the number of holes increases in proportion to the increase in the cross-sectional area of the shell 46. In other words, the distributed holes 58 define progressively increasing open areas from the closed end to the open end of the shell 46. Moreover, as seen in FIGURE 2, the holes 58 are distributed only throughout a portion of the circumference, or periphery, of the shell to obtain a directional heating effect which will be pointed out more particularly hereinafter.
In general, the premixed gaseous fuel and air mixture which is supplied under pressure to the pipe 26 is initially ignited by electrodes 44 and due to the low pressure zone created between the edge of the lip 40 of the nozzle and the conical deflector portion 48 of the shell, a flame retention ring is formed within the annular conical chamber 46 which serves to ignite the main stream of the combustible mixture. The combustible mixture thus burns externally of the refractory shell 46 within the combustion chamber 10 thus heating the shell 46 to a high degree of incandescence. The flame sweeps across the entire external surface of the refractory shell, and since the only exit for the flue gases is through the distributed openings in the shell, the entire shell is heated to incandescence. The directional heating effect is obtained by the oblique edge of the nozzle lip 40 such that the major portion of the combustible mixture is directed towards the lower zone of the combustion shell, and, in addition, by reason of the fact that as shown in FIGURE 2 the upper sector of the shell 46 is solid. This is of particular value in heat exchanger units wherein the air flow across the heat exchanger is transverse to the axis thereof, and thus the upper surface of the combustion shell must not be overheated.
As alluded to hereinbefore, substantially all of the combustible mixture is burned externally of the shell 46 and since the rim 54 of the shell has gas tight engagement with the combustion shell 10, all of the flue gases must flow through the perforated shell into the interior thereof at all times to the flue gas header 16. Moreover, while in the illustrated embodiment the pressurized burner is shown mounted horizontally, the burner is readily adapted for vertical installation, either upward or downward.
With reference to FIGURES 3 through 6, the refractory shell can have various distributed port arrangements and can be of different cross-sectional configurations. Thus, in FIGURE 3 the truncated cone shell 46 is shown having distributed openings 58 from its closed end to its open end extending throughout a portion of its periphery. In FIGURE 4 a shell 60 of substantially square truncated pyramid configuration may have distributed openings 58 on two or three adjacent sides. In FIGURE 5 a shell 62 of hexagonal cross-section may have distributed openings 58 on two to five adjacent sides, and in FIGURE 6 a polygonal shell 64 having five straight sides may have distributed openings 58 on two to four adjacent sides. In all embodiments shown in FIGURES 3 through 6 the directional heating effect will be obtained by virtue of the distributed holes being located throughout only a portion of the periphery of the refractory shell.
While the embodiments of the invention as herein disclosed constitutes preferred forms, it is to be understood that other forms might be adopted.
What is claimed is as follows:
1. A radiant burner for use with a pressurized gaseous combustible mixture including, a combustion chamber, a burner nozzle extending into said combustion chamber, an elongate, tapered, perforate refractory shell having a closed end and an open end and being of increasing crosssectional area from the closed end to its open end, the open end of said shell being remote from said nozzle and having a rim portion in gas tight engagement with said combustion shell, said refractory shell having a conical flame deflector on its closed end with its apex extending into said nozzle, said nozzle having a lip with an edge spaced from said conical flame deflector and an outwardly flared frusto conical edge spaced from said lip and defining an annular chamber of conical section thcrebetween, said lip having a plurality of holes therethrough communicating with said annular chamber, and means for initially igniting the combustible mixture flowing through said nozzle such that after initial ignition the combustible mixture in said annular chamber will constitute an ignition ring for the combustible mixture, whereby said combustible mixture will burn externally of said shell within said combustion chamber throughout the length of said shell so as to heat the shell to incandescence and the flue gases will flow through the perforate shell into the interior thereof.
2. The radiant burner set forth in claim 1 wherein said nozzle is substantially cylindrical, wherein the edge of said lip is oblique to the axis of said nozzle, and wherein the refractory shell is imperforate throughout a segment of its periphery throughout its length so as to produce a directional heating effect and preclude overheating of predesignated surfaces of the combustion chamber.
References Cited by the Examiner UNITED STATES PATENTS 807,244 12/ 1905 Clamond 15899 1,752,000 3/1930 Horne. 2,255,298 9/1941 Reichelm 1581l6 2,348,901 5/1944 Handley 158113 X FOREIGN PATENTS 557,304 5/1937 Belgium. 906,254 12/1945 France.
FREDERICK L. MATTESON, IR., Primary Examiner.