US2614622A - Electric ignition and automatic pilot for gaseous fuel burners - Google Patents

Description

Oct. 21, 1952 s. e. ESKIN 2,614,622

ELECTRIC IGNITION AND AUTOMATIC PILOT FOR GASEOUS FUEL BURNERS Filed May 4, 1948 I N V EN TOR. Jame/4 G. ESKIN. M-

TORNE K Patented Oct. 21, 1952 ELECTRIC IGNITIO PILOT FOR GASEO N AND AUTOMATIC US FUEL BURNERS Samuel George Eskin, Los Angeles, Calif., assignor to Robertshaw-Fulton'q Controls Company, 'Youngwood, Pa., a corporation of Delaware Application May 4, 1948,.Serial No; 24,936

"This invention relates to control andignition systems for fuel burners and, more particularly,

to combined thermoelectric pilot contrpl and electric ignition apparatus for domestic gas ranges.

[It has long been recognized that electric ignitionand control systems are desirable for gas range ovens provided such apparatus can be "manufactured and sold without too great expense. Electric ignition permits realization of the so-call'ed fcold oven and'is not as dependent upon uniform quality of gas as are'most flash tube systems. Automatic pilot controls have in 4 large part depended upon relatively expensive time delay and other electrically operated devices which have retarded acceptance for use .on domestic ranges due to initial cost and upkeep expense; r

' An object of this invention is to combine'electric ignition and automatic pilot control in a relatively inexpensive andsinipl'e" arrangement applicableto domestic gas ranges.

Another'object of the invention is to utilize electric energy from a commercial source for oven ignition purposes only and to discontinue consumption of such energy during normal operation of the' oven.

- Another object of the invention is to-eliminate special time delay mechanisms and electrically operated valves. I

Another-object of the invention is to facilitate servicing of the apparatus when installed on a range and permit ready access to the component parts. I

Other objects and advantages will become apparent from the following'description taken in connection with the accompanying drawing which is a schematic view of an oven burner installation having the control and ignition systern applied thereto.

Referring more particularly to the drawing, an oven at shown in broken lines in the drawing is provided with a main burner l2 and a pilot burner l4 located in lighting proximitythereto. The flow of fuel is conducted to the'main burner l2 by a main fuel pipe it under control ofthe usual'co'mbined oven thermostat and gas shutoff cock l8 to which a conduit 20 for supplying fuel to the pilot burner I4 is connected. As is customaryin such control devices, the manual rotation of "the shut-off cock [8 to closed 'position will shut off flow of fuel in both the-main fuel pipe l'B and the conduit 20, but operation of the combined thermostat when satisfied will serve to shut off fuel in the main fuel pipe 16 1- Claim. (01. 158128) partition 30.

*ber 34. j

only. As such devices are well known, further description is deemed unnecessary.

Interposed in the main fuel pipe 16 between the shut-off cock 3 and the main burner I2 is the automatic pilot control .device 22 previously mentioned. The device 22 comprises a hollow casing 24 having an inlet 26 and an outlet 28 to which opposite ends of the main fuel'pipe l6 are connected respectively. A partition 30' extending across the interior of the casing 24 serves to separate theinlet 26 from the outlet 28 so that flow of fuel therebetween is permitted only by way of an axial opening 32 formed in the The flow offuel through the opening 32 is under control of acontrol means shown as a valve member 34 which is adapted tobe seated on the side of the partition 30 adjacent the inlet 26-.- The valve member 34 is provided with'a "stem 36 which extends through an apertured partition 38 and carries an armature'member'40 on its projecting end. A'coil spring 4! *is operative between the valve member 34 and' -the apertured partition 38 for biasing the valve member I 34 1 toward its seat on the 1 partition 30 to establish-the closed position of the valve mem- -The armature member 40 forms part. of an electromagnetic means and is adaptedfor move- 'ment between attracted and released positions relative to the pole faces of a horseshoemagnet 42 according to the energization or deenergization respectively of a winding 44 associated with the magnet 42. Due to the provision of the coil spring 4|, the armature member 40 is "biased to its released position and resetting means tof'be describedhereinafter are employed "to placeit in the attracted position. Thewinding 44 is ener'gi'zed'by themoelectric current-generated by a thermocouple 46 which iselectrically connected to the winding 44 and is-located to be "heated by a flame atthe pilotburner 4. It 'will be understood that the energy so generated is insufiicient to attract the armature'40 from its released position but is sufficient to retain it' in the attracted position upon completion or-the resetting operation.

' The reset means comprise a re'set' stem' 48 which extends exteriorly of the casing 24 at the end opposite the magnet 42. The-*innerend of the reset stem 48 extends axially through the opening 32 and terminates adjacent the valve member 34." Aclosure disc 50 is carried-on-the "reset stem 48 forseating upon-the underside of the partition 3|] to interrupt the flow of fuel through the opening 32 when the valve member 34 is disengaged from its seat during the resetting operation. It will be understood that where the pilot burner I4 is dispensed with and the thermocouple 46 made responsive to the flame from the main burner l2, that the closure disc 58 could be omitted. It will further be understood that the casing 24 and associated parts are shown in schematic form herein and suitable provision would be made in commercial struc tures for leakage prevention and other necessary requirements not forming part of the essential arrangement herein disclosed.

The ignition system of this invention com-1 prises an igniter 52 in the form of a coil of wire of suitable electrical resistivity which is positioned to ignite the fuel issuing from the pilot,

burner I4 when the wire is brought to igniting temperature. The igniter is adapted to be ener-e gized for such purpose from a suitable source of electric energy such as the domestic current supply. To this end, a transformer 54 is provided in this embodiment and has its primary coil connected at one end to a line wire 55 and the opposite end connected to a line wire 58. One terminal of the secondary coil of the transformer 54 is connected by a wire 60 to one terminal of the, igniter 52 while the other terminal of the secondary of transformer 54 is connected by a wire 62 to the opposite terminal of the igniter 52. Since the igniter 52 need only be energized during the resetting operation, suitable switching means are employed in the described series circuit to maintain the circuit normally open. To this end, the reset stem 48 is provided with an enlarged head 64 positioned exteriorly of the casing 24. A coil spring 66 is operative between the enlarged head 64 and the underside of the casing 24 to retain the reset stem 48 in an outwardly projected position with the closure disc 50 spaced from the partition 30. A single pole switching device is incorporated in the enlarged head 64 by the provision of arecess 63 .therein within which a pair of resilient switch arms are positioned with their oppositely curved ends H in spaced relation. The opposite ends of the resilient switch arms 10 are connected to opposite ends of the wire 60 in series circuit rran men A momentary-contact push-button i2 is reciprocable relative to the enlarged head 54 into engagement with the curved ends 'H- ofthe resilient switch arms, 10 for closing the igniter circuit. The push button 72 projects through a partition 14 extending across the recess 68 and providing a, bearing for the button 12. A collar 16 carried by the push button 12 is engaged on one side by a flange 18 formed on the enlarged head 64. Such engagement prevents ejection of the push button 72 from the enlarged head 64 under bias of a coil spring 80 which is operative between the opposite side of the collar 16 and the underside of the partition 74. The projecting end of the push button 12 beyond the flange 18 is adapted to be engaged by the operator for axial movement of the push button 12 relative to the reset stem 48. It will be understood that suitable provision for insulation, terminal connections and other common electrical requirements will be provided in the commercial form of switch.

In the operation of the device described, the parts may be assumed to be in the position shown inthedrawingwith the shut-off cock. I8 occupying an off position to prevent flowof fuel to the main burner I2 and the pilot burner 14. R0- tation of the shut-01f cock [8 to an open position will simultaneously set the temperature at which the oven thermostat combined therewith will operate. Fuel is thus permitted to flow through the conduit 20 to the pilot burner 14.

Manual. operation of the reset stem 48 is then conducted by pressure applied to the enlarged head 64 and simultaneously to the push button Such operation serves to close the circuit to the igniter 52 by engagement of the push button 12 with the resilient switch arms 70. Moreover, the axial movement of the reset stem 48 serves to disengage the valve member 34 from the partition and also to seat the armature member against the pole faces of the magnet 42. However, due to the simultaneous seating of the closure disc 56 on the partition 30, the flow of fuel in the pipe Hi to the main burner I2 is interrupted during this resetting operation.

The igniter52 quickly reaches igniting temperature and serves to ignite the fuel flowing from the pilot burner 14. The thermocouple 46 becomes heated by the flame atthe pilot burner 14, thus energizing the winding 44 sufficiently to retain the armature 40 in its attracted position. The push button 12 and the reset stem 43 are returned to their outwardly projected positions upon release of manual pressure thereon, whereupon the igniter 52 is deenergized and the closure disc 58 no longer prevents flow of fuel to the main burner l2. Since the valve member 34 is now retained in open position due to the operation of the electro-magnetic means, the passage of fuel between the inlet 26 and outlet 28 is now established and such fuel flowing from the main burner I2 is ignited by the flame at the pilot burner l4. The apparatus is now in normal running condition with the main burner [2 under control of the oven thermostat incorporated with the shut-off cock l8.

Should the flame at the pilot burner M become extinguished, then the thermocouple 46 will cool serving to deenergize the winding 44 and release the armature member 40 for movement under bias ofv the coil spring 4|. Since the armature 40 and the valve member 34 are connected by the valve stem 36' for joint operation, the valve member' 34 is caused to become closed to shut off flow of fuel to the main burner 12.

It will be apparent that the single push operation described for ignition and resetting purposes can be varied at the will of the operator. For example, the system may be operated in such manner that only the pilot burner I4 is ignited and no resetting operation occurs until a later time. In this method of operation the shut-01f cock isopened to a set temperature for the oven [0 and the push button 12 is pushed in and held for about three seconds. The enlarged head 64 remains unoperated at, this time so that the safety valve member 34 remains seated and no fuel flows to the main burner. The igniter 52 being energized the fuel at the pilot burner-l4 is ignited and the thermocouple becomes heated. The oven burner to can be supplied with fuel at any time after the thermocouple, 46 is heated in the discretion of the operator by merely operating the enlarged head 84. This member may immediately be released and the main burner ID will ignite instantaneously.

- Since the apparatus described is provided with r the closure disc 50 which is operated by movement of the reset stem 48, the igniter 52 can immediately be ,reenergized after a period of 7 burner operation. 'In such restarting operation the thermocouple 46 remains heated and the valve member 34 is held in the open position due to continued energization of winding 44. Accordingly, the shut-off cock is rotated to open position and the reset stem 48 is manually operated as previously described. No fuel can flow to the main burner l2 at this time due to the seating of the closure disc 50 but the fuel flowing from 'modified form, the relatively fixed contact means,

comparable to the switch arms 10, could be carried by the casing 24 for engagement by relatively movable contact means, comparable to the push button 72, and carried on the enlarged head 64 but not movable relative thereto. In such event, the operation of the reset stem 43 would also serve to energize the igniter '52 with a single push motion.

These and other changes may be made in the details of construction and arrangement of parts within the scope of the appended claim and the invention is not limited to the precise embodiment shown and described herein.

I claim:

In a control and ignition system for fuel burning apparatus having main and pilot burners and a source of electric energy, the combination of an electric igniter for the pilot burner connected to be energized from the source, a casing having a fuel inlet and an outlet to the main burner, a valve member reciprocable in said casing for controlling the flow of fuel between said inlet and outlet, thermoelectric means responsive to a flame at the pilot burner, electromagnetic means having a coil member and an armature member con- '6 a nected to the thermoelectric means for energization thereby sufficiently to hold said armature in attracted position relative tosaid coil member but insufficiently to cause movement of said armature member from a released position, means operable between said casing and Valve member for biasing the latter to closed position, connecting means between said armature and valve membars for joint movement therebetween, a reset stem extending exteriorly of said casing and being axially movable by manual operation relative to said casing from an initial position into operative position for overcoming said bias and resetting said armature member in said attracted position and said valve member in an open position, means carried by said reset stem for interrupting the flow of fuel between said inlet and outlet during the resetting operation, a normally open switch controlling energization of said igniter and having an operating portion'carried by said reset stem for movement independently thereof to closed position when said armature member is moved to said attracted position, means for biasing said reset stem to said initial position upon cessation of said manual operation, and means for biasing said switch to open position for deenergizing said igniter upon completion of said resetting operation.

SAMUEL GEORGE ESKIN.

REFERENCES CITED 7 The following references are of record in the file of this patent:

UNITED STATES PATENTS

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