US 3313490 A
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Description (OCR text may contain errors)
Apnl 11, 1967 R. s. LOVELAND 3,313,490 YIELDABLE SHEET METAL BURNER SPUD CONTAINING I A NON-DEFORMABLE ORIFICE MEMBER Filed Jan. 6,-1965 H INVENI'OR.
--- 20632 \SZ'ZOVMD United States Patent Ofifice Patented Apr. 11, 1967 3,313,490 YELDABLE SHEET METAL BURNER SPUD CONTAINING A NON-DEFORMABLE ORI- FICE MEMBER Roger S. Loveland, Torrance, Califi, assignor to Honeywell Inc., a corporation of Delaware Filed Jan. 6, 1965, Ser. No. 423,786 4 Claims. (Cl. 239-596) This invention relates to safety pilots and, more particularly to a pilot burner and flame sensing arrangement having a novel supporting bracket construction for assembling the parts thereof and a novel burner spud construction which produces an inexpensive safety pilot.
While safety pilots of the above-mentioned type are well known in the art, it has been the constant effort of the industry to produce more reliable and less expensive designs to meet competition in this highly developed art.
One of the objects of this invention is to provide a simple, sturdy and easy to manufacture assembly of a pilot burner and a flame sensing unit.
Another object is to provide a safety pilot which is of such simple construction and so readily assembled as to reduce the cost of manufacture thereof over prior art constructions.
A still further object of the invention is to provide an inexpensive burner spud construction which is less susceptible to the transfer of heat by conduction from the pilot burner head with which it is associated.
A still further object of the invention is to provide a pilot burner spud with an adjustably positioned and frictionally held orifice mem ber therein.
Another object of the invention is to provide a burner spud wherein an orifice member thereof may be selectively positioned therein to adapt the orifice member to be used in a plurality of burners.
Still further objects of the invention will become apparent upon reading the following detailed description of the invention in conjunction with the accompanying drawing wherein:
FIGURE 1 is an elevational view of a preferred embodiment of the safety pilot with portions of the pilot burner and supporting bracket broken away;
FIGURE 2 is an elevational view of the safety pilot shown in FIGURE 1, viewed from the righthand side of FIGURE 1;
FIGURE 3 is a cross-sectional view of the invention taken along line 3-3 of FIGURE 1;
FIGURE 4 is a plan view of a portion of the bracket before it has been assembled with another portion of the bracket and the associated pilot burner;
FIGURE 5 is an enlarged cross-sectional view of the burner spud; and
FIGURE 6 is a cross-sectional view of a modification of the burner spud.
Referring to FIGURE 1 of the drawing, the safety pilot consists of a mounting bracket, generally designated by the reference numeral 10, for supporting a flame sensing means 11 (thermocouple) and a pilot burner, generally designated by the reference numeral 12. The bracket consists of a mounting plate or arm 13 having apertures 14 through the vertically extending arm thereof and a horizontally extending arm or supporting plate 15 terminating in fingers 16 and 17. The supporting plate 18 has an aperture 19 therein, through which a support sleeve 20 for the flame sensing unit extends with an interference fit, and a second aperture 21, through which a tubular burner body 22 extends.
The burner body 22 has an enlarged diameter portion 23 at the lower end thereof providing an abutment shoulder 24 which bears against the under surface of the plate 18. An annular groove 25 in the body 22 is preferably spaced from the abutment shoulder 24 a distance slightly less than the thickness of the plate 18 and is slightly greater than the thickness of the plate 15 so that when the fingers 16 and 17 are positioned in the annular groove and crimped toward each other, the metal intermediate the ends of the fingers will cold flow to press down against the top surface of the plate 18 and upwardly against the upper side wall of the annular groove to draw the laterally extending plate-like arm 15 and plate 18 tightly together and firmly hold the burner body 22 in assembled relationship therewith. Preferably, the end of the plate 18 bears against the adjacent surface of the mounting plate or arm 13 to help prevent relative rotation between the plate 18 and plate 15 around the burner body. A primary air opening 22a is provided in a wall of the burner body below the mounting plate 18 for introducing air into the burner. A target type of burner head 26 is mounted in the upper end of the burner body 22 while the lower end of the burner body has a threaded bore 27 of larger diameter than bore 28, which is the inside diameter of the burner body.
A burner spud, generally designated by the reference numeral 29, is made of thin sheet metal and has a lower cylindrical portion 29a, which has an inside diameter slightly larger than the outside diameter of a supply pipe 30, an adjacent reduced diameter portion 2%, a second reduced diameter portion 29c and an upper and still further reduced portion 29d. Adjustably mounted in the reduced diameter portion 290, is a cup-shaped or flanged flat plate or disc orifice member 31 having an axially extending supporting wall which is axially slidealble in the portion 29c with a sufficient frictional fit as to cause it to remain in whatever position it is selectively placed and regardless of the gas pressure to which it is exposed. For the burner head illustrated in the drawing, the orifice member is positioned as shown in the drawing. For other types of .burner heads, the orifice member 31 is possibly located at a different position in the portion 290 although there are some cases where one of these orifice positions will satisfy more than one type of burner. Also, there are burners wherein it is necessary to eliminate the portion 29b to place the portion 290 adjacent the portion 29a, depending upon how far it is desired to have the orifice 31a of the orifice member located with respect to a lower end of the burner spud and the burner head. The portion 29d serves the function of confining the gas issuing from the orifice 31a and to aid in direct ing the gas into the burner head positioned above the spud. The lower end of the portion 29a is outwardly flared at 29s to provide a shoulder which bears against the beveled shoulder 27a provided between the inner end of the bore 27 and the bore 28 of the burner body. A compression fitting including a compression sleeve 32 connected through a flangible collar 33 to a clamping nut 34 surrounds the tube 30 and seals against the flange portion 29e and forces the flange 2912 into sealing engagement with the shoulder 27a.
The flame sensing member 11 may be a mercury filled bulb or a thermocouple or some other suitable means for receiving the flame of the pilot burner and is held in the supporting sleeve 20 by means of a clamping nut 35 in a conventional manner.
The modification of the burner spud down in FIGURE 6 is generally designated by the reference numeral 36 and consists of a sheet metal spud which is similar to the one in FIGURE 5 with the exception that the portion 2% has been eliminated and a portion in the form of a sleeve 37 has been placed over the portion 36d and soldered thereto at 38. Primary air openings or apertures 39 are formed in the wall of the sleeve 37 at a point slightly above the upper end of the portion $60!. This spud 36 is for use in 3 a burner having a somewhat different construction from the burner disclosed in FIGURES 1 and 2.
While the burner spud could be constructed by various means, the preferred construction thereof is to draw and punch sheet metal in the forms illustrated with the result that the walls of the spud are quite thin. Therefore, the wall of the portion 29c will yield rather than cause buckling of the cup-shaped orifice member 31 if the pressure on the orifice member is too great as it is adjustably positioned in the spud. This will prevent deformation of the material surrounding orifice 31a and, therefore, prevent misalignment of the orifice 31a as to cause malfunction thereof.
By inserting the burner body through the aperture 21 in the plate 18 and sliding the fingers 16 and 17 in the annular grooves on opposite sides of the burner body and then crimping the ends of the fingers towards each other, the expansion of the metal at areas 16a and 17a locks the bracket plates and the burner together. However, it would be possible to position the burner body 22 in the opening 21 by an interference fit and merely rely on the fingers 16 and 17 to secure the burner body 22 to the arm or plate 15.
Operation With the safety pilot above described mounted adjacent a main burner by means of mounting bolts (not shown) extending through the openings 14 and into a suitable support on the main burner, and the burner 22 connected to a source of gas supply to conduit 30 and the flame sensor 11 connected to a safety device controlling the flow of fuel through the conduit 30, the safety pilot is ready to be placed in operation. By turning on the gas supply, it will pass through the orifice 31a of the burner spud and be directed by the portion 29d into the burner head and inspirate primary air through the opening 22a for mixing on the surface of the target burner head 26. Ignition of the gas at the target burner will cause flames to flow onto the flame sensor 11 and outwardly and upwardly through the inverted channel-shaped wings of the pilot burner 26 toward the associated main burner or burners. Due to the thinness of the walls of the burner spud and the distance that heat would have to be conducted from the burner head down through the burner body, and through the spud to the orifice member, the orifice member remains relatively cool and therefore does not candle, thus providing a satisfactory flame at all times. It is thus seen that the details of construction of the above described invention produce an inexpensive safety pilot that is easy to assemble yet provides one that is reliable in operation.
Furthermore, providing a spud construction wherein there is a low rejection rate due to the manner in which it is made, the reduction in cost as a result thereof is of benefit to the public, in addition to the invention being a definite improvement over the prior art. As modifications may be made in the invention without departing from the spirit thereof, the scope of the invention should be determined from the appended claims.
1. The combination comprising: a pilot burner having a burner body with inner and outer walls and a burner head; a thin-wall, open-ended, sheet metal tubular spud having an inlet end and an outlet end and positioned in said burner body; and an orifice member having a supporting wall stronger than the wall of said spud which spud wall would yield during assembly before deformation of the supporting wall, and being selectively positionable and frictionally held in said tubular spud intermedite its ends, said tubular spud having a uniform diameter from the discharge end thereof to a point near said orifice member.
2. The combination defined in claim 1 wherein said tubular spud has two end and one central aligned and stepped diameter portions, with said orifice member adjustably positioned in said central portion, and said central portion being spaced from the inner wall of said burner body.
3. A pilot burner comprising a generally tubular body having first and second open ends, a thin-wall tubular spud positioned at the first end of said body for directing gas into said body, and a flat plate orifice member having a flange thereon positioned within said spud with the flange thereof supporting the orifice member so as to direct gas generally axially of said spud, the strength of the wall of said spud being such that it will yield during assembly, before said orifice member will be deformed, to prevent misalignment of the orifice therein.
4. A pilot burner as defined in claim 3 wherein said spud has at least three coaxially aligned and stepped openended portions and wherein said orifice member is adjustably positioned in the intermediate one of said stepped portions.
References Cited by the Examiner M. HENSON WOOD, JR., Primary Examiner.
VAN C. WILKS, Assistant Examiner.
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