Patent GB-1048167-A (GB)
Title: Double burner oven system and method
IPC: F24C3/12
Filed: 1965-07-21
Abstract: 1,048,167. Valves. ROBERTSHAW CONTROLS CO. July 21, 1965 [July 22, 1964], No. 31068/65. Heading F2V. [Also in Division F4] A control apparatus for a bake burner 12 and a broil burner 13 of an oven 10 comprises a selector valve 19 adapted to supply gas to either the bake or the broil burner and a first automatic flame failure valve 16 which supplies gas to the selector valve 19 or to the bake burner 12 only, Fig. 9 (not shown), when a flame is sensed at a controller pilot burner 41 supplied with gas through an adjustable thermostatic valve 46. The supply of gas from the selector valve 19 to the broil burner 13 is also controlled by a second automatic flame-failure valve 67 which opens when a flame is sensed at a second controller pilot burner 87 supplied with gas by the selector valve 19 when the latter is set to supply the broil burner 13. When the selector valve 19 is turned to supply the broil burner the second automatic valve 67 is in closed position and the gas pressure across the valve causes a diaphragm 110 carrying a contact 111 to bridge contacts 103, 105 thus energizing an ignition transformer 99 and an ignition coil 97. The second controller pilot burner 87 therefore ignites and consequently the second automatic valve 67 opens. The diaphragm 110 then breaks the ignition circuit. The first automatic valve 16, Fig. 2 (not shown), comprises a valve member 33 biased to closed position by a snap-spring 34 and opened by a lever arrangement 36 actuated by an expansible element 35 connected by a conduit 40 to a temperature-sensing bulb 39 heated by the controller pilot burner 41. Gas is supplied at all tmes by an outlet 42 of the valve 16 to a standby pilot burner 44 which ignites the controller pilot burner. The adjustable thermostat valve 46 supplying the controller pilot 41, comprises a valve member 53, Fig. 3 (not shown), urged to closed position by a spring 54 and adapted to be opened by a lever 57 fulcrumed on an axially movable shaft 58, moved by rotating a control knob 59. The control knob determines an off position, a desired temperature range position or a broil position. The lever 57 is actuated by an expansible element 63 connected to a temperature-sensing bulb 65 disposed in the oven 10. The second automatic flame-failure valve 67, Fig. 4 (not shown), comprises a valve member 73 urged to closed position by a spring 74 and adapted to be opened by a first lever 75 having an end 77 engaging an end 78 of a second lever 76, the other end of which engages the valve member 73. The first lever 75 is actuated by an expansible element 82 connected to a temperature-sensing bulb 85 heated by the second controller pilot burner 87. A second valve member 91 urged to open position by a spring 92 is also actuated by the levers 75, 76 and opens and closes with the other valve member 73 to control the supply of gas to a second standby pilot burner 95 which is not supplied through the selector valve 19 so that if the selector valve is operated to cut-off the broil burner and then quickly returned to the supply position, the second standby pilot burner 95 will ignite the broil burner and the second controller pilot burner 87. The selector valve 19 comprises a rotatable plug valve 18, Figs. 5, 6, 7, 8 (not shown), rotatable in a housing 21. The housing has two ports 22, 23 connected to the bake burner and the automatic flame failure valve 67 and two further ports connected by conduits 27, 27<SP>1</SP>, Fig. 8 (not shown), to the second controller pilot burner 87 and to the gas supply manifold 14. The plug 18 has a central gas-inlet port leading to a radial bore 29; a slot 30 on the plug connects the two conduits 27, 27<SP>1</SP> when the radial bore 29 is aligned with the port 23. In the modification of Fig. 9 (not shown), the supply of gas to the selector valve 119 is controlled by a thermostatic valve 129 actuated by an expansible element 136 connected to a bulb 138 sensing the temperature of the oven.