US2980178A - Pilot burner - Google Patents

Description

April 18, 1961 A. H. SEARS PILOT BURNER Filed Nov. 28, 1958 YINVENTOR. QRTHUR H SEARS PILOT BURNER Arthur H. Sears, Chicago, 11]., assignor to Harper-Wyman Company, Chicago, 111., a corporation of Illinois Filed Nov. 28, 1958, Ser. No. 777,077 g e 2 Claims. (Cl. 158-115) The present invention relates to a pilot burner and has Patented Apr. 18, 1961.

of the main burner ports 20 are located above'the charging port 14 structure which communicates with the burner chamber 17 to which gas may be supplied under the control of a conventional valve, not shown. The charging port structure includes a small radially outwardly directed port 22 above which is located an upwardly opening slot 24 communicating with the port 22 and the for its primary purpose the provision of a new and improved pilot burner of the type commonly called a tiny pilot utilized to ignite gas supplied from the charging or lighter jet of an associated main burner.

A primary object of the invention is to provide the pilot burner with shielding to prevent overheating and; clogging of the tiny pilot, to protect it against extinction by gas discharged from the main burner which is to be lighted by the pilot burner or by extraneous air currents or boilovers or the like which mightotherwise fall upon it, and to make it easy to align the pilot burner relative to the main burner. r

A further object of the present invention isto provide a pilot of the'character aforesaid including a perforated baffle, such as a wire mesh screen, located between it and an associated main burner to be lighted and which screen acts as a barrier preventing extinction of the pilot burner flame by 'gas supplied from the associated main burner and which will, at the same time, permit the pilot burner effectively to ignite the gas whereby the main larger hollow portion 25. When'gas is supplied to the main burner, some of the gas is projected radially outwardly from the port 22 to the pilot burner and some of the gas flows upwardly through slot 24 toward the ports 20 so that the gas iszignited by the pilot burner and it in turn ignites the gas flowing from the main burner ports 20.

The pilot burner 10. of the present invention includes a small tube or needle 30 having a small opening for the discharge'of gas and which is commonly called a tiny pilot or micro pilotf' It is supplied with gas at all times to maintain a continuous pilot flame, thegas being supplied through a tube 32, a coupling nut 34 detachably coupling the .tube32 to a hollow externallyihreaded fitting 36 havingits upperend closed by an integral plate-like portion38 to whichis suitablysecured, as by peening, an aperturedshield supporting or mountingplate 40 and to which the pilot burner tube or needle 30 is also secured.

In order to prevent the minute opening of the tiny pilot 30- from becoming clogged or overheated as well as to prevent the pilot flame from being extinguished by a blast of gas fromthe main burner or by extraneous air currents or the like, the pilot is shielded by two different means. These means include, first, a perforated baffle suchas a wire mesh screen 42 disposed between the needle 30.and the charging port and, second, an overlying burner will be lighted. This screen also serves to maintain the pilot burner cooler and spreads gas supplied to it from the main burner sothat accurate location of the pilot burner is not required.

A further object of the present invention is to provide a pilot burner as described in the preceding paragraph with an overlying shield adapted to carry away products of combustion from the pilot whereby these products will not be likely to clog the charging port of the main burner from which gas is supplied to the pilot for lighting of the main burner.

Other objects and advantages of the invention will become apparent from the ensuing description of an illustrative embodiment of the invention, in the course of which reference is had to the accompanying drawings,

in which: 1

Fig. 1 is a fragmentary view illustrating the pilot burner of the present invention in combinationwwith a main burner, the latter being illustrated partially and in section o y; 7 r t Fig. 2 is an enlarged front elevational view of the pilot burner of the present invention, the view being taken along the line 2-2 of Fig. 1; and

Fig. 3 is a vertical sectional view taken along the line 33 of Fig. 2. I

Referring now to the drawing and first to Fig. 1, the pilot burner of the present invention is indicated as a .whole by the reference'character 10. It is shown in the shield in the form of a housing indicated as a whole by the reference character. 44; V,

The screen 42i-is located a short distance in. front of the needle 30 andrises a short distance above it but does not apart side walls 52 and 54. These are provided with horizontalfianges 56 at their front lower ends whereby the shield canbe secured to the mounting plate 40 by crimping the edge portions 58 of the latter over the flanges as best illustrated in Fig. 2. The screen 42 is secured to the plate 40 by crimping the forward portion 60 of the mounting plate 40 over a flanged foot portion 62 of the screen. a

The screen 42 extends substantially across the width of the shield 44 as shown in Fig. 2 and it is to be noted also that the screen, as shown in Fig; 3, is inclined at an angle of about 15 upwardly and toward the tube 30. Also it should be noted that the screen does not extend so as to be vertically above the tube 30 and there is substantial spacing between the screen and tube to permit difiusion of the gas blast before it reaches the tube.

The screen is inclined at an angle between about 11 to 18, but it'hassbeen found that best results are obtainable if the screen is inclined at'about a 15 angle, as illustrated. The described construction has been found to operate satisfactorily for ignition of the gas discharged from the charging port 22 and, at the same time, pref vents the pilotflame from being extinguished by the sudpilottube 30 cool, so that gas burned thereat is prevented port or lighter jet structure indicatedv as a whole by the reference character'l l. f e v Themain burner includes a burner base'16, a burner chamber 17, and an overlyingburner cap .18 having an annular series of main burner ports 20 discharging genfrom being cracked and forming'gummy residues which It is important that there be a space would clog. it.

' such as the space 48 above the screen and that the screen f also thatthe screen be inclined at an angle such as the 15 erally radially outwardly and somewhat upwardly; Some} extend a short distance above the top of the'tube 30 and angle an angle of inclination less than about 11 "enemas is used,"the "gas has a tendency to burn at the pilot burner side of the screen and the flame does not readily pass over the screen to ignite the gas at the outside of the screen, i.e., to ignite the gas at the charging port 22, 24. Also, if the screen extends too far above the pilot tube, for example .to the top 46 of the shield, the flame will burn only at the inside of the screen and not be. passed over it. The flame should have only its tip above the screen. It is preferable also that the pilot burner flame not impinge on the screen 42.. If desired, a somewhat greater angle of inclination than 15 could be used and the pilot tube 30 could be spaced a greater distance from it to avoid impingement of the flame upon the screen.

In order to conduct the products of combustion from the pilot burner flame away from the charging port area or region, the shield is provided with the side walls 52 and the top 46 is inclined somewhat upwardly and away from the charging port to provide a chimney or flue effect. To enhance this eflect, the top and side walls are extended rearwardly away from the pilot tube 30.

In operation, the pilot burner will be continuously supplied with a desired quantity of gas through the tube 32. This gas is discharged through the'tiny pilot needle 30 to provide a continuous pilot flame to the right of the -screen 42 so that at least the tip of the flame extends above the top of the screen. When gas is supplied to the main burner chamber 17, some of the gas is projected toward the screen through the port 22 and some is directed above the charging port structure 14 toward main burner ports 20 so that when this flow is ignited the gas issuing from the main burnerports is also ignited.

The screen 42 prevents the gas discharge from the port 22 from blowing out the pilot burner flame. Some of the gas flows over the top of the screen but this does not blow out the pilot burner flame. The. gas thus supplied to the pilot burner from the main burner is ignited and flashes back over the screen tothe main burner. The

screen serves to diffuse the gas passing through it to the pilot flame so that accurate alignment of pilot and charging port is not required and so that the pilot flame will "not be blown out and, after ignition, it serves to keep the charging port flame from directly impinging upon the pilot burner. V

The products of combustion resulting from the pilot burner flame are conducted away from the main burner by the shield 44 whichhas a flue effect resulting from the extended side walls and "top plate with its upward inclination.

The shield with its top plate 46 also prevents extraneous material such as boil-overs from extinguishing the pilot flame.

The screen is made of some suitable material, prefera-,

ably stainless steel. The screen should have a mesh between 30 and and a 40 mesh, i.e., 40 meshes per inch, has been found quite satisfactory. Perforated material other-than'screening can be used.

While the present invention has been'described with an illustrative embodiment thereof, these details are not intended to be limitative of the invention except insofar as set forth in the accompanying claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

'1. A pilot burner for a main burner having a port for discharge of gas to be ignited by the pilot'burne'r including in combination, a pilot burner extending to a predetermined height, and a screen type baflle disposed on one side of the pilot burner, said b'aflie being inclined upwardly and toward the pilot burner, and extending a short distance above the height of the pilot burner, a shield overlying the pilot burner and baffl'e structure, saidshield having side walls spaced from the pilot burner and said screen extending substantially, from one side wall to the other, said side walls extending some distance above the screen and from the screen some distance beyond the opposite side of the pilot burner, and a top wall interconnecting said side walls, said top wall being inclined upwardly and rearwardly from a position in front of the screen to a position on said opposite side of the pilot burner.

2. A pilot burner as claimed in claim 1 wherein said screen and overlying shield are secured to a mounting plateforming a part of the pilot burner. 7

References Cited in the file of this patent UNITED STATES PATENTS 1,994,860 Matson Mar. 19, 1935 4 FOREIGN PATENTS 483,780 Great Britain Apr. 26, 1938 440,680 Italy n--. Oct. 16, 1948

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