US2501850A - Control and ignition system for - Google Patents

Description

March 28, 1950 w. s. KUNZLER CONTROL AND IGNITION SYSTEM FOR FUEL BURNERS Filed Nov. 16, 1948 INVENTOR. WILLIAM 5. KUNZLER.

19 7" TOPNE 7.

Patented Mar. 28, 1950 CONTROL AND IGNITION SYSTEM FOR FUEL BURNERS William S. Kunzler, Greensburg, Pa., assignor to Robertshaw-Fulton Controls Company, Greenlburg, Pa., a corporation of Delaware Application November 16, 1948, Serial No. 60,327

Claims. 1

This invention relates to control devices and, more particularly, to automatic pilot and ignition controls for fuel burners.

Controls of the type indicated have utilized thermoelectric current generated in response to a pilot burner flame for maintaining the main fuel burner control in operating condition until the pilot flame becomes extinguished. In the operating condition, the main burner control is electrically energized from commercial sources to permit flow of fuel to the main burner. Such flow may be independently controlled by room thermostats, limit switches and other devices where required without interference 'with the functioning of the automatic pilot control.

An object of this invention is to condition the main burner control for energization upon successful completion of a resetting operation on the automatic pilot.

Another object of the invention is to combine the resetting and conditioning operations into a simple rectilinear movement of a push button.

Another object of the invention is to include an automatic igniting operation for the pilot burner with the resetting operation.

Another object of the invention is to completely shut off the flow of fuel to both the main and pilot burners when the automatic pilot control functions in the absence of a flame at the pilot burner.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawing wherein:

Fig. 1 is a schematic view of a fuel burning system showing the improved control device applied thereto and in the off position.

i Fig. 2 is a similar schematic view of the improved control device showing the parts in the starting position, and

Fig. 3 is a schematic view similar to Fig. 2 but showing the parts in the normal running position.

Referring more particularly to the drawing, the improved control device is shown in Fig. 1 in connection with a fuel burning system comprising a main burner l0 which is supplied with gaseous fuel by the main fuel pipe l2. The flow of fuel in the pipe I2 is under control of a solenoid gas valve l4 of any suitable type which opens upon energization of the solenoid and closes when the solenoid is effectively deenergized. Located in lighting proximity to the main burner III is a pilot burner l6 which is supplied with fuel through a conduit 18 connected to the main fuel pipe 12 ahead of the solenoid gas valve l4.

Interposed in the conduit I8 is a pilot control valve mechanism designated generally by the reference numeral 20. Any conventional pilot valve mechanism 20 may be employed and, in this embodiment, includes an angular body member 22 having an inlet opening 24 and an outlet opening 26. One end of the conduit I8 is connected to the inlet 24 and the opposite end of the conduit I8 is connected to the outlet opening 26. A passage 28 provides communication between the inlet opening 24 and the outlet opening 26 in the valve body 22 and passage of fuel therebetween is under control of a pilot valve member 30 which is biased toward a closed position relative to a valve seat 32 by means of a coil spring 34. Operation of the valve member 30 to open position relative to its seat 32 is effected by movement of a valve stem 36 which projects from the valve member 30 to the exterior of the valve body 22 for this purpose.

Thermoelectric means are employed for maintaining the valve member 30 in open position after the same has been moved to such position. In this embodiment, a thermocouple 38 is positioned on a bracket 40 carried by the pilot burner IE to respond to the flame thereof. The thermocouple leads are connected to a winding 42 of an electromagnetic means including a horseshoe magnet 44 and a movable armature 46 therefor which is positioned to cooperate with the pole faces thereof. Normally, the armature 46 is biased to 2. released position by an armature spring 48 and is adapted to be placed in an attracted position by resetting means now to be described.

The resetting means include an actuator member 50 which may be in the form of a push button projecting from the fuel burner installation in any convenient position for manual operation. Slidably mounted in the actuator member 50 is a reset member 52 in the form of a stem having a swivel connection 54 with an armature stem 55 projecting from the armature member 46. The reset member 52 carries a pair of spaced collars 58 positioned intemediate the connection 54 and the actuator member 50. Yieldable means in the form of a coil spring 60 is operative between the actuator member 50 and the adjacent collar 58 for biasing the actuator member 50 outwardly from the end of the reset member 52. Such movement of the actuator member 50 is limited by engagement of a shoulder 62 thereon with a stationary portion of the burner installation.

Electric igniting means in the form of a coil of resistance wire 64 is provided for the pilot 65, 58 are supported on a relatively stationary portion of the burner installation and suitably insulated therefrom.

The relatively movable contact means of the switch means 66, 68 are both carried on one lever of a pair, the other lever I2 being pivoted at one end 14 on a relatively stationary portion of the burner installation. The free end of the lever 12 is bifurcated for the reception of the portion of the reset member 52 extending between the collars 58 thereon. This lever 12 also carries, intermediate its ends, a pivot 15 for the lever 10 which is thereby pivoted intermediate the switch means 56, B8. The free end of the lever 10 is apertured for the reception of the reset member. 52 which is slidable therethrough. The apertured free end of the lever Ill is positioned on the reset member 52 intermediate the coil spring 60 and the underside of the actuator member 50. A projection 18 from the other lever 12 overlies the valve stem 36 for operating the same as shown schematically in Fig. 1 of the drawing.

The circuit connections for the solenoid gas valve l4 and the igniter means 64 will be described in connection with the description of the operation of the device which now proceeds. It may be noted that the electrical portion of the system is energized from a commercial source of current supply through a step-down transformer 80 and that a limit switch 82, room thermostat 84, and a limiting resistor 86 for the igniter 64 are provided in the system.

As previously indicated, the parts are shown in Fig. 1 of the drawing in the oil? position, e. g., the solenoid gas valve i4 is deenergized and the pilot valve is closed. In this position, the pair of levers 10, I2 occupy a position wherein the switch means 56, 68 are in open position and the armature means 46 is in released position relative to the pole faces of the magnet 44. A starting operation can be conducted by manual pressure applied to the actuator member to produce the condition illustrated in Fig. 2 of the drawing. In this starting position, the lever 12 is rotated on its pivot I4 due to engagement of the free end thereof with the collars 58 on the reset member 52. Such rotation of the lever 12 in a clockwise direction serves to move the pivot 16 of the lever 10 also in a clockwise direction while the actuator member 50 engages the free end of this lever 10 and assists in similar clockwise movement there- 01'. Upon completion of the starting operation, the armature means 46 is positioned against the pole faces of the magnet 44 and further movement of the reset member 52 is prevented.

The parts are now in the position shown in Fig.2 wherein it will be observed that the projection 18 on the lever 12 has depressed the valve stem 36 for opening the pilot valve member 30. Passage of fuel through the conduit l8 from the main fuel pipe l2 to the pilot burner 16 is thus permitted. As the switch means 66 are now in closed position, due to movement of the relatively movable contact means thereof into engagement with the related fixed contact means, a circuit for the igniting means 64 is established as follows:

former 80, wire 88, limiting resistor 88, igniting means 64, wire 90, switch means 66 and wire a:

to the right-hand end of the secondary of transv former 80.

Ignition of the pilot burner It should now occur and heating of the thermocouple 58 results. The actuator membe 50 is manually held in its depressed position for approximately 30 seconds until sufllcient current is generated by the thermocouple 38 in winding 32 to energize the electromagnetic' means sufllciently to retain the armature 4B in its attracted position. The actuator member 50 is then released and the parts assume the position shown in Fig. 3 of the drawing for the normal running condition of the burner installation.

Upon release of the actuator member 50 after the starting operation, the lever 10 is biased by the coil spring 60 to follow the movement of the actuator member 50, to its outwardly projected position. The reset member 52, however, is retained in its set position due to the armature member 46 being held in attracted position by the .18, however, serves to maintain the pilot valve from the left-hand end of the secondary of trans- 3D in open position due to retention of the lever 12 in its pivoted position. The switch means 66 has been moved to open position due to separation of the relatively movable contact means thereof from the fixed contact means and the circuit of the igniting means 64 is broken. Concomitantly therewith, the switch means 68 moves to its closed position due to engagement of the relatively movable contact means with the fixed contactmeans thereof by the counterclockwise movement of the lever 10. 1

A circuit for the solenoid gas valve I4 is now established as follows: left-hand end of the secondary of transformer 80, wire 88, wire 94, solenoid valve coil 96, wire 98, room thermostat 84, limit switch 82, wire I 00, switch means 68, wire l 02 and wire 92 to the right-hand end of the secondary of transformer 80. Assuming that the contacts of the room thermostat 84 and limit switch 82 are closed, then the solenoid gas valve I4 is energized for movement to open position to permit fuel to flow to the main burner l0. Such iuel is ignited by the flame at the pilot burner i6 and the system is in normal running condition.

It will be apparent that operation of either the room thermostat 84 or limit switch 82 to open position will serve to deenergize the solenoid 93 of the gas valve H to shut off flow of fuel to the main burner l0 without interference with the functioning of the automatic pilot control.

In theevent that the flame at the pilot burner i6 is extinguished, then the thermocouple 35 will cool and cease to generate current for energizing the magnet winding 42. Release of the armature means 46 then occurs with consequent movement of the reset member 52 from its reset position under bias of the armature spring 48. The lever 12 is thereby moved in a counterclockwise direction on its pivot 14 and carries the pivot 16 for the lever 10 also in a counterclockwise direction. The parts then assume the position shown in Fig. 1 of the drawings with the switch means 58 again in open position due to separation of the relatively movable contact means thereof from the fixed contact means. Thus, regardless of the closed position of the limit switch 82 and the room thermostat 84, the circuit for the solenoid 98 of the gas valve I4 is broken.

It will be observed that as long as thearmature 46 is not retained by the electromagnet M, then the switch means 68 cannot even momentarily be moved to closed position. That is, unless the pivot 16 for the lever is positioned as shown in Fig. 3 of the drawings, then the lever 10 cannot be moved counterclockwise sufficiently to cause closure of the switch means 68.

It will be understood that while a schematic form of the invention has been shown and described herein, many changes in the details of construction and arrangement of parts may be made within the scope of the appended claims without departing from the purview of th invention.

I claim:

1. A control device comprising switch means having relatively fixed and movable contacts actuable between open and closed positions, a re-. set member movable between reset and released positions, an actuator member cooperable with said reset member, electromagnetic means eiIective when energized for holding said reset member in said reset position after the same has been movedthereto bysaid actuator member, means for energizing said electromagnetic means, means for controlling the energizing operation of said energizing means including a movable member biased to a position for preventing said operation, a pair of levers operably associated with said reset and actuator members, one said lever being pivoted on the other and being adapted for actuating said movable contact means, said other lever being cooperable with said reset member for positioning said pivot, means operably associated with said other lever for movement to a controlling, position for overcoming the bias of said movable means during resetting movement of said actuator member and being maintained in said controlling position while said reset member is held in said reset position, and yieldable means operative upon reverse movement of said actuator member from resetting position when said reset member is held as aforesaid for causing said one lever to actuate said movable contact means to closed position.

2. A control device as claimed in claim 1 wherein a free end of said other lever is attached to said reset member for movement therewith for positioning said mvot, said yieldable means being effective for biasing a free end of said one lever toward said actuator member for movement therewith indepemlently of said reset member when the latter is held in said reset position.

3. A control device comprising switch means having two pairs of relatively fixed and movable contact means both actuable between open and closed position, a reset member movable between one lever to actuate one of said movable contact means to closed position, and yieldable means operative upon reverse movement of said actuator member from resetting position when said electromagnetic means is effective for causing said one lever to actuate said one contact means to open position and concomitantly actuate the other movable contact means to closed position.

4. A control device as claimed in claim 3 where-= in said one lever is pivoted intermediate said pairs of contact means for alternative closing thereof, a relatively stationary support upon which said other lever is pivoted at one end thereof and having the free end thereof attached to said reset member for movement therewith for positioning said pivot, said yieldable means being effective for biasing a free end of said one lever toward said actuator member for movement therewith independently of said reset member when the latter is held in said reset position.

5. A control device as claimed in claim 3 wherein means are provided for energizing said electromagnetic means, means for controlling the energizing operation of said energizing means includingamovable member biased to a position for preventing said operation, and means operably associated with,said other lever for movement to a.

controlling position for overcoming the bias of said movable means during resetting movement of said actuator member and being maintained in said controlling position while said reset member is held in said reset position.

WILLIAM S. KUNZLER.

REFERENCES CITED The following references are of record in the file of this patent:

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