US2840095A - Burner control system - Google Patents

Description

J. H. THORNBERY 2,840,095

BURNER CONTROL SYSTEM June 24,1958

2 Sheets-Sheet 1 Original Filed Sept. 3, 1947 June 24, 1958 J. H. lHORNBERY 2,840,095

BURNER CONTROL SYSTEM Original Filed Sept. 3, 1947 2 Sheets-Sheet 2 United States PatentO 2,840,095 BURNER CONTROL SYSTEM John H. Thornbery, Whitefish Bay, Wis., .assignor to Baso Inc., Milwaukee, Wis., a corporation of Wisconsin Continuation of application Serial No. 771,900, September 3, 1947. This application October 23, 1953, Serial No. 388,039

Claims. (31. 137 66 While the particular system which I shall describe.

hereinafter in connection with the'drawings is a thermoelectric safety shut-ofi system for use in conjunction with sectional furnaces and similarmultiple burner installations, it is to be understood that the invention is not limited to such use but maybe employed for all similar purposes as suitable. or desired.

In systems of the class described, it is desirable to have means for shutting off the supply of gas to,one ormore of the burner sections for certain periods of time- It is also desirable to keep the pilots ignited so that, when needed, the burner sections may be returned to operation quickly and without going through the process of reigniting the pilots. It is further desirable to have safety shut-off means operable in case of pilot failure.

Heretofore it hasfrequently been the practice to provide safety shut-off means for only the supply of fuel for the burner and to waste the small amount of pilot gas. This practice has, however, been found to be hazardous, particularly with the increased use of liquid petroleum gases, since the high heat content and other properties of liquid petroleum gases more readily cause an explosive gas-air mixture. It is therefore desirable to provide not only a shut-01f for the burner, but also a shut-off for the pilot gas. It is further desirable to provide these various functions with the least amount of apparatus and material, and to arrange the devices in a practical manner for easy accessfor operation and repair.

One of the main objects of the present invention is to provide improved thermoelectric safety shut-01f means which is operable to shut offnot only the supply of fuel for the main burner, but also the supply of fuel forthe pilot when the pilot is extinguished. 1

Another object of the invention is to provide a thermoelectric safety shut-off which functions in the manner described and with the advantages set forth, and which is also adapted for shutting off the supply of gas to one or more burner sections for certain periods of time while keeping the pilots ignited so that, when needed, the burner sections may be returned to operation quickly and without going through the process ofreigniting the pilots.

Another object of the invention is to provide an improved thermoelectric safety shut-off of the character described having various features of novelty and advantages, andwhich is particularly characterized by its simplicity in construction, its economy in manufacture, and its eflectiveness'in use; also by its ,abilityrto provide the various functions with the least amount of apparatus, and

by the practical manner in which the devices are arranged for easy access for operation and repair.

Another object is to provide an electromagnetic device, a source of low power for energizing the device, an electric circuit of low resistance including the source and the device and comprising concentric leads, and a head for the device having lead connection means opening to the exterior of the device when the head is assembled thereto and wherein the head has connections interior of the device between the lead connection means for continuance of the circuit to and through the electromagnetic device. Another object is to provide apparatus wherein there are at least two electromagnetic devices each comprising an electromagnet and an armature, a single thermoelectric means for energizing the electromagnets sufficiently to hold the annatures in attracted position and a'low resistance circuit including the thermoelectric means and the electromagnetic devices comprising concentric leads. Further objects and advantages of the invention will be apparent from the following detailed description, taken in connection with the accompanying drawings, in which:

Figure 1 is a more or less schematic view of a burner control system embodying the present invention;

Figure 2 is an elevational viewof the thermoelectric safety shut-off for the pilot, looking from the left in Figure 1; V

Figure 3 is a longitudinal axial section through the pilot shut-off, taken on the line 33 of Figure 2;

Figure 4 is a detail sectional view showing the magnet coil connected between the connectors of the device shown in Figures'2 and 3; and V a Figure 5 is a wiring diagram of the system. Referring first to Figures 1, 2, and 3, the burner shown at 10 in Figure 1 is any suitable or preferred main burner, for example, one of'the main burner sections of a sectional main burner or one of the main burners of a multiple main burner installation, or any other main burner, for example, for an oven, room or space heater,

, gas burner, the fuel supply pipe is preferably connected to the main burner through a suitable air and gas admixture chamber, and fuel delivery nozzle (not shown), as well understood in the art.

Figure 1 shows a pilot burner 14 in juxtaposition to the main burner 10. The pilot burner 14 is adapted to provide a pilot light 15 for lighting the main burner 10. A fuel supply pipe 16, connected, for example, to pipe 11 anterior of the connection to the main burner through control device 12 and thermoelectric shut-off valve 13, supplies gaseous fuel to the pilot burner 14 through a thermoelectric pilot shut-off valve 17.

The thermoelectric safety shut-off valve 13 is, in general, of the type shown and described in more detail in my copending application Serial No. 738,455, filed March 31, 1947, which has matured into United States Patent No. 2,503,459, issued April 11, 1950, or of any other suitable or preferred type. It comprises a valve body 18 having an inlet 19 and an outlet 20. Contiguous sections of pipe 21 connected to pipe 11 through control device 12 are connected to inlet 19 and outlet 20, and one of these pipe sections 21 lead to the main burner 10 for supplying fuel thereto. A port or passage 22 provides for communication between inlet 19 and outlet Ztlhand a safety shut-off valve, shown in dotted lines at 23, is adapted to seat upon a valve seat at one end of port 22 to shut off the flow of fuel for the main burner.

Patented June 24, 1958 An electromagnet having a magnet frame, as shown at 24 in Figure 1, and a coil, as shown at 25 in Figure 5, is adapted for holding armature 26 connected to valve 23 in attracted position and, thereby, valve 25open when the thermoelectric generator 27-such as a thermocouple or thermopile-is heated by the pilot flame. When the pilot burner 14 is extinguished, the electroinagnet ceases to hold valve 23 open, and this valve moves to closed position, for example, under the action of a spring 28 to shut off the supply of fuel to main burner 10.

A reset button 29 is adapted to be pressed inwardly to move valve 23 to open position with accompanyingmovement of armature 26 to attracted position and to hold the armature in attracted position. until the pilot burner is ignited and heats the thermoelectric generator 27 to energize the electromagnetsufiiciently to retain armature 2 6. attracted and valve 23 open. Flow interrupter means 30, for example, in the form of a resilient bellows as disclosed in my above identified application, or of any other suitable form, shuts off the flow of fuel to the main burner during the resetting operation and until valve 23 is held in open position and button 29 is released and returns to its outwardly projecting position'with accompanying operation of the flow interrupter means to open position. I

Although the form. of the thermoelectric generator 27 may vary widely within the scope of the present inven' tion, the thermoelectric generatorselected' for illustration is shown as a thermocouple which, with the leads therefor, may be similar to the thermocouple and leads more fully disclosed in Oscar J. Leins Patent No. 2,126,564, patentedAugust 9, 1938. Thethermocoupl'e 27 may be supported, for example, by a bracket 31 on pilot burner 14 whichumay be provided with lugs 32 for mounting same in appropriate position,

For the purpose of the present description, suffice it to state that the particular thermocouple 27 selected for illustration comprises an outer tubular thermocouple element, shown at 33 in Figures 1 and 5, and an inner thermocouple element 34, as shown in Figure 5. The inner thermocouple element is joined at one end to the outer thermocouple element to form the thermojunction 35 which is I placed in position to be heated by the pilot flame. An inner lead conductor 36 is joined to the inner thermocouple element to form an internal thermojunction, and an outertubular lead conductor 37 surrounds the inner lead conductor and is connected to the outer thermocouple element, for example, through a sleeve 38 to form a third thermojunction. The inner lead conductor 36 is insulated from the outer lead'conductor 37, for example, by a wrapping of insulation 39 on the inner lead conductor.

The thermoelectric safety shut-off valve 17 for the pilot burner 14 comprises a valve body 40 having an inlet 41 and outlet 42 as shown in Figure 3. Contiguous sections of pipe 16 leading from pipe 11 to pilot burner 14 are connected to inlet 41and outlet 42. A port or passage 43 provides for communication between inlet 41 and outlet 42, and a pilot shut-off valve 44 is adapted to' seat upon a valve seat at one end of passage 43 to shut off the flow of fuel to the pilot burner.

At the opposite end of valve body 40 is a connection head 45 for the thermoelectric generator. This connection head 45 has an annular flange 46 clamped to the adjacent end of valve body 40, preferably with a gasket therebetween, by a union nut 47. Connector pins or terminal tip members 48 aremounted in the:inner end of connection head 45'and are insulated therefrom by insulation 49. Coil 50, wound'around the legs of mag net frame 51, has one'end connected at 52 in circuit with one of pins 48, which pin is connected in circuit with the other pin 48 by an insulated Wire 53. The other end of coil 50 is connected to connection head 45 through the attachment at 54 of the base of magnet frame 51 thereto.

A stem 55 is connected at one end to pilot shut-off valve 44. Stem 55 extends for reciprocatory movement through an opening in the inner end of a magnet and armature housing 56. Armature 57 is mounted upon the end of stem 55 disposed in housing 56. Housing 56 fits telescopically in valve body 40. The outer end of housing 56 is peened, for example, at 58 into an annular groove in the inner end of connection head 45. A valve spring seating member 59 abuts the inner end of housing 56, and packing 60 is preferably interposed therebetween. Valve spring 61 'is in the form of a coiled compression spring interposed between pilot shut-off valve 44 and seating member 59..

. "For resettingva'lve 44 to open position and armature 57 to attracted position, reset stem 62 is mounted for reciprocatory movement axially of valve 44. The inner end of stem 62 isheaded and has a suitable washer 63 secured'thereto which cooperates with an annular rib 64 on valve body to seal the valve body against leakage along the reset stem when the stem is in its outwardly projected position as shown in Figure 3. The outer end of reset stem 62 has a reset button 66 which is guided in the valve body 40. A coiled spring 67 is interposed between reset button 66' and packing 68, and returns button 66 to its outwardly projected position when released, and also maintains the packing in sealing relation to the opening throughwhichstem 62 extends.

For providing quick detachableconnection between either pin 48 and the adjacent ends of lead conductors 36 and 37, the end of the inner lead conductor 36 has a connector cone 70 which seats, for example, in a recess in the outer end of pin .48 and is adapted to be detachably clamped in contact therewith by a connector sleeve 71 which screws into either threaded opening 72. Sleeve 71 is insulated from connector cone 70 at 73, and, when screwed into place, sleeve 71 completes the circuit from I outer lead conductor 37 to the connection head of the valve body 40. I v V a v A second concentric lead conductor 36, 37', similar to the lead conductor 36, 37, is detachably connected to the connection head 45 by a sleeve 71' which screws into the other opening 72, clamping the connector cone on its inner end in contact with the otherpin 48 and completing the circuit from the outerlead conductor 37 to the connection head 45 of the valve body 40. The quick detachable connection head 71 is similar to the quick detachable connection at 71, and therefore the description of same will not be repeated in detail.

The opposite end of the inner lead conductor 36' has a connector cone 75 which is adapted to be moved by a manual release nut or finger piece 76 into and out of contact-with a connector pin 77 at the shut-off device 13 in the manner described in my previously identified copending application, or in any other suitable manner. One end of coil 25 at device 13 is connected in circuit with pin 77, and the other end of coil 25 is connected, for example, in circuit with the outer lead conductor 37' through terminal bushing 78 at valve body 18. The manual release nut or finger piece 76 screws inwardly on bushing 78 to move connector cone 75 into contact with pin 77, andloutwardly on bushing 78 to move connector cone 75 out of contact with pin 77;

Thevalve body 40 has a flat part 80 at which there are threaded openings 81 by means of which an angular mounting bracket 82 may be attached to the body by screws 83 or the like.

The bracket 82 may be mounted, for example, upon a part 84 in proximity to the furnace, and part 84 may have an opening 85 for access to reset button 66.

The circuit for the system illustrated in Figures 1 through 3 is shown in Figure 5, ground connections being shown at 88, 89 and connector at 531' "The magnet coils 25 and 50 of valves 13 and 17 are thus connected in parallelwith each other within the thermoelectric circuit.

The operation of the apparatus is, in general, as follows:

When the pilot .burner 14 is ignited, the heat thereof on the thermojunction 35 of thermoelectric generator 33 produces 'a thermoelectric current in coil 50, and assuming that the manual release contacts are closed at 75, 77, a thermoelectric current is also produced in coil 25. The thermoelectric current produces magnetic fields of sufficient strength so that When armatures 57 and 26 are placed in contact with the pole ends of the magnet frames 51 and 24 by pushing the reset buttons 66 and 29 inwardly, the magnetic attraction holds the armatures in attracted position and the shut-off valves 44 and 23 in open position as long as the pilot is ignited. The gas or other fuel enters the shut-off valves 17 and 13 through the inlets thereof, and flows out through the outlets to the pilot and to the main burner.

At any time during operation, the valve 23 may be closed by screwing the manual release 76 in a direction to screw contact 75 out of contact withcontact 77, which disables the thermoelectric circuit for the magnet coil 25 while maintaining the circuit for the coil 50. This shut-off of the valve 23, with the accompanying shutoff of fuel for the main burner 10, does not, however, shut ofl? the pilot valve 14, since magnet coils 25 and 50 are in parallel. As a result, the 'pilot burner may continue ignited so that, upon need, the main burner may be returned to operation quickly and without going through the process of reigniting the pilot by the simple expedient of closing contacts at 75, 77 and resetting armature 26 to attracted position and valve 23 to open position by depressing reset button 29. The shutoff valve 13, with its manual control of contacts 75, 77 may thus replace and eliminate the usual gas cock or other shut-off means.

In the event that the pilot burner 4 is extinguished or fails otherwise, the holding action of the electromagnets ceases to be sulficient to hold armatures 26 and 57 in attracted position. As a result, both valves 23 and 44 move to closed position, for example, under the action of springs 28 and 61 to shut off the supply of fuel both to the main burner and to the pilot burner. This provides 100% shut-off of gas.

The apparatus is reset by depressing button 66, igniting pilot 14, closing contacts at 75, 77, and depressing button 29.

In Figure 4 the magnet coil 50, which corresponds with the coil 50 of Figure 3, is connected between the connectors 48 for series connection of the system. Where series connection is desired Figure 4 provides the mechanism for such connection.

The embodiments of the invention shown in the drawings are for illustrative purposes only, and it is to be expressly understood that the'drawings and the accompanying specification are not to be construed as a definition of the limits or scope of the invention, reference being had to the appended claims for that purpose.

I claim:

1. In combination, electrically operated control means, a housing enclosing said control means, a terminal connector on said housing having a pair of contact heads connected to said control means, a plurality of threaded openings in said terminal connector having their axes in alignment with said contact heads and at least one of said openings being aligned with one contact head for connecting one side of said control means to one side of a power source through concentric leads and at least one other of said openings being in alignment with said other contact head for connecting the other side of said control means to the other side of said power source through concentric leads.

2. In combination, electrically operated control means, a housing for said control means formed with an open- 6 ing, a terminal connector closing said housing opening and having means affording a connection with said housing at the margin of said opening, said terminal connector comprising a pair of contact heads connected to said control means, a plurality of threaded openings in said terminal connector adapted to mate with concentric leads, said openings having their axes in alignment with said contact heads, and at least one of said openings being aligned with one contact head for connecting one side of said control means to one side of a power source and at least one other of said openings being in alignment with said other contact head for connecting the other side of said control means to the other side of said power source.

3. In combination, a control body formed with an opening, electrically operated control means within said control body, a housing for said control means, a terminal connector fixed to said housing and having means affording connection between said terminal connector and said control body at the margin of said opening to close said opening, said terminal connector comprising a pair of contact heads connected to said control means, and a plurality of threaded openings in said terminal connector in alignment with said contact'heads, at least one of said openings being aligned withone contact head for connecting one side of said control means to one side of a power source and at least one other of said openings being in alignment with said other contact head for connecting the other side of said control means to the other side of said power source through concentric leads.

4. The combination with a pair of low resistance electromagnetic devices each having electrically operated control means simultaneously energizable from a single thermo-couple and connected in circuit therewith by low resistance electrical leads, of a terminal connector fixed to one of said electromagnetic devices having a pair of contact heads connected to said control means and a plurality of threaded openings in said terminal connector in alignment with said contact heads, at least one of said openings being aligned with one contact head for connecting one side of said one electromagnetic device to one side of said thermoelectric generator by low resistance leads and at least one other of said openings being in alignment with said other contact head for connecting the other side of said one electromagnetic device to the other side of said thermocouple through the other of said electromagnetic devices.

5. In combination, electrically operated control means, a housing for said control means, a terminal connector on said housing carrying said control means and having a pair of contact heads in circuit with said control means, a plurality of threaded openings in said terminal connector having their axes in alignment with said con-tact heads and at least one of said openings being aligned without: contact head for connecting one side of said control means to one side of a power source and at least one other of said openings being in alignment with said other contact head for connecting the other side of said control means to the other side of said power source.

References Cited in the file of this patent UNITED STATES PATENTS 2,323,628 Smith July 6, 1943 2,414,236 McCarty Ian. 14, 1947 2,562,289 Ashcraft July 31, 1951 2,566,372 Ray Sept. 4, 1951 2,765,029 Wolff Oct. 2, 1956 FOREIGN PATENTS 7 226,895 Great Britain Jan. 6, 1925

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