US2688363A

US2688363A - Pilot burner and detector electrode control for furnaces

Info

Publication number: US2688363A
Application number: US186189A
Authority: US
Inventors: Taricco Lawrence
Original assignee: LEE B METTLER Co
Current assignee: LEE B METTLER Co
Priority date: 1950-09-22
Filing date: 1950-09-22
Publication date: 1954-09-07
Anticipated expiration: 1971-09-07

Description

Sept. 7, 1954 1.. TARICCO 2,688,363

PILOT BURNER AND DETECTOR ELECTRODE CONTROL FOR FURNACES Filed Sept. 22, 1950 2 Sheets-Sheet 1 "m j gwhmn ii: 9

l I I l l I I INVENTOR. ZflWRf/VCE 7772/64'0,

L. TARICCO PILOT BURNER AND DETECTOR ELECTRODE CONTROL FOR FURNACES Filed Sept. 22, 1950 2 Sheets-Sheet 2 INVENTOR. ZHW/QE/VCE Me/cco,

Patented Sept. 7, 1954 UNITED STATES TENT OFFICE PILOT BURNER AND DETECTOR ELECTRODE CONTROL FOR FURNACES Application September 22, 1950, Serial No. 186,189

3 Claims.

My invention relates to pilot burner and control means for, furnaces, and included in the objects of my invention are:

First, to provide a pilot burner and a control means which incorporates a flame sensitive control adapted to form a part of an electric circuit capable of effecting complete shutoff of the main burner and pilot burner in the event of failure of the pilot burner, whether the main burner is in operation or not, so as to avoid accumulation of unburned gases, and also incorporates a spark ignitor capable of manual or automatic operation to re-ignite the pilot burner in the event of such failure.

Second, to provide a means of this class which is capable of fitting within a tubular shell of small diameter so as to be installed as a unit within the limited space available in conventional furnace burner assemblies.

With'the above and other objects in view, as may appear hereinafter, reference is made to the accompanying drawings in which:

Figure 1 is a partial sectional, partial elevational view of a furnace and burner assembly showing my control means in position.

Figure 2 is an end view of the main burner assembly showing a position of the pilot valve.

Figure 3 is a partial elevational, partial longitudinal sectional view of my pilot burner and control means.

Figure 4 is an enlarged fragmentary longitudinal sectional view thereof taken through. i l of Figure 3.

Figure 5, Figure 6 and Figure 7 are transverse sectional views taken through 5-5, 6-B and 7-? of Figure 3.

Figure 8 is a fragmentary partial sectional, partial elevational view taken in the region of the pilot burner jet.

My pilot burner and control means may be adapted for use with a wide range of furnace burners. For purposes of illustration, however,

one type of burner is shown. A conventional furnace A is provided with a burner opening in which is fitted a burner unit 13 having a bank of burner orifices connected by a suitable manifold C with a fuel supply D controlled by a main valve and regulator E. Air is supplied to the burner through a duct F. If forced draft is employed, the duct connects with the discharged end of a blower G.

With reference particularly to Figures 3-8, my pilot burner and control means includes a pilot burner block I in the form of a cylinder having a slot 2 in one side. The slot is intersected by an offset axially directed port 3. Fitted in the block in alignment with the port 3 and extending across the slot 2 is a pilot burner nozzle or jet 4 which is screw threaded into the block and communicates with a supply pipe 3 also screw threaded into the block.

The pilot burner block s'lideably supports one end of the sleeve 6 which is axially movable to control the effective area of the slot. The sleeve 6 forms a covering or shell for the supply pipe and extends rearwardly from the pilot burner block. The rear end of the sleeve is slideable on an end block a to which the supply pipe 5 is connected. A fuel passage leads through the end block 7 and means are provided for connection to a supply line 9.

Fitted on the forward or right hand end of the pilot burner block I, as viewed in the drawings, is a burner shell or tube it. Open at its extremity fitted in the open end of the shell It, and protruding therefrom is an axially extending centered plate H which is electrically groruided to the shell. Adjacent the root or inner end of the plate l l, the sleeve 6 is provided with air ports i2. Disposed adjacent one side of the plate ii and protruding from the shell it is a detector electrode 53, the detector electrode being disposed parallel to the plate H. Within the shell it, the electrode I 3 is covered by an insulator sleeve M which in turn fits within a guard tube i5 extending through an aperture provided in the pilot burner block i. The inner end of the detector electrode it is joined by a suitable connector means it to a cable ll which extends through an appropriate opening in the base block or the end block l.

Mounted at the opposite side of the plate II from the detector electrode [3 is a spark electrode It preferably disposed within the shell ID. The spark. electrode is supported within a high tension insulating sleeve is which extends through an accommodation opening within the pilot burner block i. The inner end of the sleeve 59 is provided with a socket which receives a connector Ell joined to the inner end of the electrode E9. The connector 28 forms one end of a high tension cable 2! which likewise passes through the end block 1.

The cables ll and 2| extend to control boxes 22 containing conventional circuit components, that is, the detector electrode is electrically connected to an amplifier, the output of which is capable of controlling the main valve or the main burner and pilot burner assemblage. As the amplifier and the control circuit is conventional, it is not shown. The high tension cable is conneeted to a high tension transformer, not shown, which, in turn, may be controlled in a conventional manner by a manually or automatically operated switch. Operation of my pilot burner and the control means is as follows:

It will be observed that the sleeve 6 and shell H] are relatively small in diameter and coaxial so that the extended end of the shell H) may be inserted through the conventional pilot burner aperture provided in the main burner unit B. Gases issuing from the nozzle 1; mix the primary air entering through the slot 2 and flow outwardly through the extended end of the shell 10. The air and gas mixture is ignited by the sparking electrode [3 when the transformer with which it is connected is operated. The spark passes between the electrode 18 and the plate II. The resulting flame surrounds the plate I l and the detector electrode 13 so that the ionized gases present in the flame form a partial conduetor between the electrode 13 and the plate H. The variation in conductivity between the condition in which the pilot burner is in operation and the condition in which the flame is extinguished is utilized in a conventional electronic circuit and, if necessary, amplified for control of the main burner valve.

It will be observed that all of the means necessary for ignition, operation and control of the pilot burner are arranged in a particularly compact construction so that little, if any alteration in a conventional furnace burner need be made to accommodate the pilot burner and associated parts.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. In a pilot burner for use with a furnace burner and control means therefor including an instrumentality sensitive to the conductivity of a flame, the combination of: a pilot burner tube adapted to be disposed with one end adjacent said furnace burner; a pilot burner nozzle and air supply means intermediate the ends of said tube adapted to deliver a fuel-air mixture to the end thereof adjacent said furnace burner to produce a flame issuing from said tube; a grounded metal vane dividing the discharge end of said tube into semicircular openings and continuing therefrom in the path of a flame issuing therefrom to divide said path in a longitudinally extending diametrical plane; a detector electrode also extending from said tube at one lateral side of said vane in substantial parallelism therewith and electrically associated with said instrumentality to effect operation of said burner in response to the presence or absence of said pilot flame; and a sparking electrode at the flame end of said tube on the opposite lateral side of said grounded metal vane from said detector electrode, and adapted for connection to a high voltage source to eifect ignition of fuel issuing from said tube, said grounded metal vane tending to prevent gases ionized by said sparking electrode from passing around said vane to said detector electrode.

2. In a pilot burner for use with a furnace burner and control means therefor including an instrumentality sensitive to the conductivity of a flame, the combination of a pilot burner nozzle block; a pilot burner tube adapted to extend therefrom to a position in proximity to said furnace burner; a sleeve similar in diameter to said burner tube extending in the opposite direction from said block; a pilot burner fuel nozzle in said block, said block and sleeve forming an air control means for said jet and cooperating therewith to supply a fuel-air mixture to the extended end of said pilot burner tube; a grounded metal vane disposed diametrically in said tube and projecting longitudinally therefrom whereby the exposed pilot flame issuing from said tube is diametrically divided by said vane; a detector electrode also extending from said tube at one side of said vane substantially parallel thereto and electrically associated with said instrumentality to effect operation of said furnace burner in response to the presence or absence of said pilot flame; and a sparking electrode at the flame end of said tube on the opposite side of said grounded member from said detector electrode, and adapted for connection to a high voltage source to effect ignition of fuel issuing from said tube.

3. In a pilot burner for use with a furnace burner and control means therefor including an instrumentality sensitive to the conductivity of a flame, the combination of: a pilot burner tube adapted to be disposed with one end adjacent said furnace burner; a gas supply nozzle mounted within said tube and air supply means adjacent said nozzle to produce a flame at the end of said pilot burner tube adjacent said furnace burner; an axially directed grounded partition member dividing the discharge end of said tube diametrically to form therewith complementary semicircular discharge openings, said partition member projecting from said tube into and longitudinally dividing the path of a flame issuing therefrom; a detector electrode also extending axially from said tube in proximity to said partition member in one divided half of said flame path and electrically associated with said instrumentality to effect operation of said burner control means; and a sparking electrode extending axially through said pilot burner tube at the flame end of said tube on the opposite side of said grounded member from said detector electrode and thereby disposed in the other divided half of said flame path, and adapted for connection to a high voltage source to effect ignition of fuel issuing from said tube.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,304,200 Plein et a1 Dec. 8, 1942 2,396,146 Atwater Mar. 5, 1946 2,402,763 Longini June 25, 1946 2,430,688 Schickler Nov. 11, 1947