US 3078916 A
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Description (OCR text may contain errors)
Feb. 26, 1963 R. s. LOVELAND 3,078,916
GAS-FUELED PILOT BURNER Filed Dec. 4, 195a INVENTOR.
ROGER S. LOVELAND A TTOR/VE) nite tates 3,078,916 GAS-FUELEI) PILOT BURNER Roger S. Loveland, Torrance, Calif., assignorto Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Filed Dec. 4, 1958, Ser. No. 778,105 3 Claims. (Cl. 158-113) This invention relates to thermoelectric generators and, more particularly, it relates to an improved non-aerated target type of pilot burner of the type adapted to heat a thermocouple unit and also to ignite a main burner with which it is associated.
Generators of this type, wherein a portion of the flame from the burner is for main burner ignition, require that the thermocouple unit be uniformly heated over a fairly wide range of gas pressures so as to enable the controls energized by the unit to function properly. It is also a requirement of this type of generator that should the gas pressure become sufliciently low as to not assure lgllltion of the main burner by the pilot burner the heating of the thermocouple unit must drop off sufliciently so as to cause safety shut down of the gas flowing to the main burner at one of the controls energized by the unit. The heating controls industry has been constantly striving to perfect or improve generators of this type.
It is one of the objects of this invention to provide a less expensive thermocouple generator which will meet the requirements mentioned above.
Another object of the invention is to provide a target type of pilot burner, for use in a thermoelectric generator, which produces a flame pattern that will heat a thermocouple unit uniformly over the usual range of operating pressures in gas supply lines and which will cause quick shut down of the gas flowing to a burner upon the occurrence of below normal gass pressures.
Another object of the invention is to provide a burner target of such a configuration that a flame developed on the target will be split into two separate flames directed generally tangential to the two sides of a thermocouple unit positioned to be heated thereby.
A still further object of the invention is to provide an improved orifice construction for a burner by providing means to direct gas transversely into the orifice through which gas flows to create a turbulent gas stream as it issues from the orifice to aid in the picking up of the necessary air to provide a proper combustible mixture.
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 the invention showing the burner in cross section;
FIGURE 2 is an end view of the generator;
FIGURE 3 is a plan view or" the generator;
FIGURE 4 is a bottom view of the orifice member in the burner spud;
FIGURE 5 is a vertical sectional view of the orifice member taken along the line 55 of FIGURE 4; and
FIGURE 6 is a fragmentary sectional view taken along line 66 of FIGURE 5.
The invention consists of a bracket 11 having a pair of holes 12 at one end thereof and a pair of holes 13 intermediate the ends thereof for selective use in mounting the bracket adjacent a main burner (not shown) for ignition thereof by the pilot burner. The bracket also has a transversely extending arm 14 with spaced holes 15 and 16 therein for selectively receiving a burner body 17 or mounting sleeve 18 for a thermocouple unit. The burner body 17 and sleeve 18 are suitably secured in the holes of the bracket, as by welding them thereto, as indicated at 19 and 20.
As the details of the flame sensing unit, the thermocouple unit or thermopile 21 form no part of this invention, it will suflice to state that it is held in the mounting sleeve 18 by means of an externally threaded ring nut 22 hearing against an annular flange on the unit (not shown) and holding the annular flange against the annular shoulder (not shown) on the inner wall of the sleeve 18. An armored cable 23 extends from the lower end of the thermocouple unit and contains a pair of leads (not shown) for connecting the thermocouple unit to other controls of a heating system.
The burner body 17 has a bore 24 in the upper portion thereof and an internally threaded and large diameter bore 25 in the lower end thereof. A burner spud 26 has an externally threaded portion 27 that is screw threaded into the bore 25 and an internally threaded portion 28 into which a ring nut 29 is screw threaded.
A pilot burner supply tube 30 extends through the ring nut 29 and through a conical clamping and sealing sleeve 31 which snugly fits around the tube 30 and is clamped thereto by the ring nut 29 being screwed against the sleeve 31 and forcing it into a stepped bore 32 between the bore 28 and a smaller diameter bore 33 intermediate the ends of the spud 26. A smaller diameter portion 26a of the spud 26 surrounds the upper end of the bore 33 and extends upwardly into the bore 24 of the burner body 17 in spaced relationship with respect to the bore 24 and to a point below the upper end of the burner body. The bore 33 terminates at its upper end at a reduced diameter bore 34 which, in turn, terminates at the lower end of a bore 35 which extends to the top of the spud 26.
A burner target, generally designated by the reference numeral 36, is formed out of sheet metal to give the appearance of a slit sleeve portion 37 that fits in the upper end of the burner body and extends for a short distance downwardly over the upper end of the portion 26a of the spud. The portion 37 spreads out at its upper end as it joins with an intermediate flat portion 38 that is inclined at a slight angle to the longitudinal axis of the sleeve portion 37. The portion 33 joins at its upper end with a generally channel shaped portion 39' that intersects the longitudinal axis of the bores 33, 34 and 35 and which is fairly close to being perpendicular to that axis.
The portion 39 has a flat target surface 39a and two outwardly and upwardly diverging side walls or skirt portions 39b and 390. Upwardly struck portions 40a and 40b are formed in the target portion 39, where the surface 39a joins the skirt portions 3% and 39c, to provide beveled grooves in the outer end of the flat surface 39a to help divide and direct a flame from the surface 39a into two upwardly and outwardly diverging flames. Also helping to divide the flame is a generally V-shaped notch 41 formed in the outer central part of the portion 39. This notch also serves to permit the flame to rise at a point further away from the thermopile when the gas pressure becomes sufliciently low and cannot produce a flame that would ignite the main burner.
A still further improvement in the pilot burner of this invention over the prior art lies in the generally cup-shaped orifice member 42, the details of which can best be seen in FIGURES 4, 5 and 6 of the drawing. The cup has a centrally disposed aperture or orifice 43 therein with a plurality of upwardly struck radial grooves 44 therein which extend from the aperture or orifice 43 to points about midway between the orifice and the side walls of the cup. It will be noticed that as gas flows into the open end of the cup 42, gas will flow straight through the orifice 42 and will also flow along the grooves 44 sub 3 stantially at right angles to the axis of the orifice 43 and into the orifice 43 to create a turbulent action in the gas as it issues from the upper end of the orifice. This turbulent action aids in the entrainment of air to form a combustible mixture which burns at the target Where it is further mixed. The orifice members closed end may also be conical in shape, with the wall surrounding the orifice 43 included upwardly and inwardly up to 25 from the horizontal, as viewed in FIGURE of the drawing, and be satisfactory. It should he noted that this Orifice construction is extremely simple and easy to manufacture as compared to prior art arrangements to accomplish a similar function.
Operation When the above described thermoelectric generator is installed in a heating system and gas is applied through tube 30 to the burner 17 and ignited at the target 36, air will be entrained at the throat of the target member 36 due to the turbulent stream of gas issuing from the orifice member 42 and will provide a flame on the target member that is divided into two basic flames that impinge on the two sides of the thermopile and flow over a main burner positioned on either or both sides of the thermopile.
Should the gas pressure becomes exceedingly low, the divided flames will pull back and rise vertically through the V-shaped notch 41 and cause very little heating of the thermopile. This will cause a quick drop in output of the thermopile which will result in the safety shut-off of the gas to the main burner at least and to the pilot burner too, if the safety valve is of the 100% shut-off type.
By having the divided flames directed generally tangential to the thermopile, there will be more uniform heating of the thermopile over a wide range of gas pressures. This is due to the fact that at the higher pressures a larger part of each of the flames will be thrown further away from the thermopile than at the lower pressures where the flames come closer together and finally ending up in one flame through the V-shaped notch at a pressure too low to ignite the main burner or burners.
It is deemed to be obvious that the functioning of this generator provides superior and all of the desired operating characteristics of devices of this type and without having to incorporate expensive designs and parts that have heretofore been used in prior art arrangements.
As it is also obvious that modifications may be made in the above described embodiment of my invention, without departing from the spirit thereof, it is to be understood that the scope of the invention is to be determined from the appended claims.
I claim as my invention:
1. A non-aerated pilot burner for use in a thermoelectric generator having a support and a longitudinally extending flame sensing unit mounted on said support and comprising -a burner body adapted to be mounted on said support in a vertical position, said burner having a spud therein, said burner also having a target above said burner body with a flat central portion intersecting and inclined to the axis of said spud and terminating in upwardly struck grooves at the sides thereof and positioned to receive burning gas from said spud and to direct a flame onto and past said unit for heating said unit and igniting a main burner, said flat central portion having a notch therein which gradually decreases in width as it extends inwardly from the outer end thereof, said spud having a coaxial orifice member therein, and grooves extending transversely from said aperture along the inner surface of said member for directing gas into said aperture at substantially a right angle to the axial flow of gas into said aperture.
2. A non-aerated pilot burner comprising a vertically extending tubular burner body having a spud with an orifice therein and a target positioned over said body so as to cause gas issuing from said orifice to impinge and burn on said target, said target having a pair of downwardly extending side walls and a substantially flat portion between said side walls for directing a first flame portion axially from said target, said target also having an upwardly extending groove in the under side of said substantially flat portion thereof along each side wall to help direct additional portions of the flame from the end of said target along opposite sides of said first flame portion in the same general direction, said substantially flat portion having a notch in its outer end to permit the flame issuing therefrom to rise therethrough at low gas pressures.
3. A pilot burner comprising a vertically extending burner body having a spud with an orifice coaxially positioned therein and a flame target positioned above said body so as to cause gas issuing from said orifice to impinge and burn on said target, said target having a pair of downwardly extending side walls for confining a flame therebetween, said target also having a substantially flat portion between said side walls for directing a first flame portion axially from the end of the target, said target also having an upwardly extending groove in the under side of said substantially flat portion along a side wall to help direct another portion of the flame from said target along a side of said first flame portion in the same general direction, said substantially flat portion having a notch in its outer end through which the flame issuing therefrom will rise when the gas pressure to the burner drops below a predetermined low level.
References Cited in the file of this patent UNITED STATES PATENTS 884,309 Biggler Apr. 7, 1908 1,229,030 Cecil June 5, 1917 1,340,226 Igou May 18, 1920 1,691,607 Kerr Nov. 13, 1928 2,524,622 Caparone Oct. 3, 1950 2,665,946 Broughton Jan. 12, 1954 2,799,330 Donges et al. July 16, 1957 2,817,696 Beck Dec. 24, 1957 2,859,263 Glickman Nov. 4, 1958 2,933,132 Beck Apr. 19, 1960 FOREIGN PATENTS 453,458 France Apr. 4, 1913 470,743 Canada Jan. 9, 1951