US2859263A - Pilot generator - Google Patents

Description

Nov. 4, 1958 R. B. GLICKMAN PILOT GENERATOR Filed July 21 1955 [MAIN BURNER JNVENTOR. 26 RICHARD B. GLICKMAN ATTORNEY 2,859,263 PILOT GENERATOR Application July 21, 1955, Serial No. 523,567 6 Claims. (Cl. 136-4) This invention relates to safety pilots and thermo-electric generators of the type wherein a pilot burner is adapted to heat a temperature responsive control member or a thermopile or thermocouple and to provide a flame for igniting a main burner. More specifically, this invention is directed to an improvement in the target'construction of an impingement type of burner for use in such a safety pilot or thermoelectric generator. a The invention is somewhat similar to the pilot fgenerator-of a copending application of Raymond P. Flagg and Ralph T. Olson, Serial No. 478,592, filed December 30, 1954,. but is structurally and functionally diflerent.

ings 15 and 16 are adapted to receive a thermocouple 17 or some other suitable temperature responsive unit (such as fluid filled bulb) so as to be heated by the burner portion of the unit. A head 1711 on the thermocouple is adapted to be held against the upper wall of the bracket 11 by means of an externally threaded nut 18 threaded into the opening 16 and bearing against the head 17a. An external lead 19 and an internal lead 20 of the thermocouple, which is of conventional construction, are adapted tobe connected to a suitable control device (not shown) to cut off the flow of fuel to the burner in the event of extinguishment of the flame heating the thermocouple or other flame sensing unit.

An opening 21 near the other end of the bracket 11 has a tubular rivet 22 extending therethrough and through an opening 23 in a target member 24, to hold the target member on the bracket 11. A threaded opening 25, in axially alignment with the opening 21, has a burner spud 26 threaded therein.

V The target 24 has an upwardly and transversely inclined surface 25 of a plate 27 that crosses the longiwith respect to the heating of the temperature responsive unit or thermocouple unit generally associated therewith.

One of the objects of the invention is'to provide a thermoelectric generator wherein the thermoelectric unit will be heated by the burner only so long as the fuel pressure is above a certain predetermined amount.

Another object of the invention-is to provide a pilot burner which will divide a flame into one for heating a temperature responsive unit and one for ignitinga main burner and is so constructed that, at subnormal pressures, the flame for heating the temperature responsive; unit will be snuffed out.

Still another object of the invention is to provide a pilot burner assembly including a bracket formed of sheet metal and wherein a tubular member is adapted to confine and direct a fuel jet onto a target, which is held on the burner bracket by means of the tubular member.

Another object of the invention is to provide a relatively simple and inexpensive pilot burner assembly which is of durable construction, inexpensive, and which does not require primary air for maintaining a flame that has proper characteristics for heating a temperature responsive unit.

Still other 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 a vertical sectional view of the invention, with a thermocouple unit shown in the mounting bracket in side elevation;

Figure 2 is a plan view of the pilot burner with the thermocouple unit omitted; and

Figure 3 is an end view of the burner assembly minus the thermocouple unit.

As can best be seen in Figure l of the drawing, the pilot burner assembly consists of a bracket member 11 formed from a sheet of heavy gage metal and to which is welded a mounting plate 12. The plate 12 has holes 13 therein to receive bolts 14, for securing the body 11 to a main burner, as illustrated in Figure 2 of the drawing. The bracket body 11 has a small opening 15 therein near one end thereof with a larger threaded opening assembly '16 in axially alignment with the opening 15. The opentudinal axis of the opening 21 and rivet 22 so that a jet of fuel issuing from the spud 26 will pass through the tubular rivet 22 and impinge on the plate surface 25 and be deflected toward the thermocouple 17. Side walls 28 extend downwardly from the two edges of the plate 27 and serve to confine or retain the burning fuel within the limits of the plate 27 and to help direct the flame toward the thermocouple 17. Arms 28a extend downwardly from the side walls 28 to a point close to or inabutting relationship with'the portion of the bracket 24 that bears against the bodyll. These arms prevent any substantial accidental bending of the target plate 27. out of its proper position. The side walls 28 are out along the lines 29 and 30 and a portion 31 of the side Walls are bent inwardly so as to form a relatively narrow slot or opening between the inner ends of these portions and to provide relatively wide side openings in the side Walls so that the flame, after impinging on the inner, surface of the plate 27, will be divided into three flames.

The flames that issue through the side walls and which are directed laterally by means of the inclined walls 31, are for the purpose of igniting one or more main burners while the flame that passes through the slot formed by the inner ends of the portions 31 is adapted to heat the thermocouple 17 under normal variations in the fuel pressure. However, upon a drop in fuel pressure below that at which reliable ignition of the main burners would take place, the flame passing through the central slot will be snuffed out, due to the fact that it is easier for the flame to flow through the two side openings and also due to the fact that the wall portions 31 provide good heat dissipation and therefore produces a cooling effect to the central slot opening, which makes flame retention more diflicult, as is well known in the art.

With this arrangement, it is possible to provide substantially uniform heating of the temperature responsive unit over fairly wide ranges of pressure diiferential and to provide safety shut down of the gas when the pressure becomes sufficiently low as to possibly permit the main burners gas supply to come on without being ignited by the pilot flame.

While I have described the preferred embodiment of the invention above, it is to be understood that variations may be made in this design by those skilled in the art without departing from the spirit of the invention. Therefore, the scope of the invention should be deter mined solely from the appended claims.

I claim:

1. An impingement target for a pilot burner comprising a target portion including a plate and side walls upon which a jet of burning and unburned, fuel is adapted to impinge, an outerextension of the plate portion of said target portion, and a single downwardly and inwardly inclined side wall at each side of said extension, the inner inclined side walls forming a relatively narrow flame flow slot therebetween and two oppositely disposed -side openings which are relatively wide so that 'at normal fuel pressures a flame will 'pass through both of the openings and said passage while atlower than normal operat-;

ing pressures the flame will pass only through the sideopenings.

2. A pilot burner for heating 'athermocouple unit and for igniting a main burner comprising a bracket having two pairs of aligned holes therein, one pair arranged to receive a thermocouple unit and the other pair arranged to receive a burner spud in one of the aligned holes and an apertured fastening means in the other hole, a target member having a plate portion secured to the bracket'by said fastening means and arranged to -'direct a flame laterally across and at an angle to the longitudinal axis of said one pair of holes, said target plate portion having a pair of inwardly struck and downwardly extending side walls having their inner ends spaced a short distance apart for dividing the flameinto three flames at high pressures and into two flames at relatively low pressures.

3. An impingement target for a pilot burner comprising a target portion including a plate upon which a jet of burning and unburned fuel is adapted to impinge, an extension on the outer end of said plate, downwardly and inwardly inclined side walls supported by said extension, the inner ends of said side walls forming a relatively narrow flame flow opening therebetween and two oppositely disposed side openings which 'are relatively wide so that at normal fuel pressures a flame will pass through both of saidwide openings and said narrow opening while at below normal operating pressures the flame will pass only through the side openings.

4. A burner for heating a flame sensing unit and for igniting a main burner comprising a bracket having two pairs of aligned holes therein, one pair arranged to receive a flame sensing unit and the other pair arranged to receive a burner spud in one of the aligned holes and an apertured fastening means in the other hole, a target member secured-to the bracket by said fastening means and aring the flame into three flames at high pressures and into two flames at relatively low pressures.

5. An impingement target for a pilot burner comprising a body portion upon which a jet-of burning and unburned fuel is adapted to impinge, an extension on said body portion downwardly extending side walls on said extension, one of said side walls being inwardly inclined toward said other side wall, the inner end of the inwardly inclined side wall forming a relatively narrow flame flow passage with the other side wall and a side opening which is relatively wide so that at normal fuel pressures a flame will pass through the side opening and'said passage while at below normal operating pressures the flame will pass onlythrough'the side opening.

'6. A thermoelectric generator comprising a thermocouple unit, aburner for heating said thermocouple unit and 'forignitin'g a main burner, a bracket for supporting said thermocouple unit, a burner spud mounted on 'said bracket, ,a target member secured to the bracket and arrangedto direct a flame impinging thereon laterally across said thermocouple unit, said target member having References Cited in the file of this patent UNITED STATES PATENTS 1,424,739 Reeves Aug. '1, 1922 2,270,798 'Guenther Jan. 20, 1942 2,363,072 Mantz Nov. 21, 1944 2,605,296 Bodey July 29, 1952 2,610,984 Weber Sept. 16, 1952 2,670,394

West Feb. 23, 1954

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