GB798913A - Control device for gaseous fuel burning appliances - Google Patents

Abstract

798,913. Controlling burners. ROBERTSHAW-FULTON CONTROLS CO. May 7, 1956 [Aug. 8. 1955], No. 14080/56. Class 75(1) [Also in Group XXIX] A gas control device for a main and pilot burner comprises a casing 10, Fig. 1 with inlet 12 connected by passage 16 to outlet 14, a safety cut off valve 22 in the passage controlled by pilot flame failure device, and timing means 24 for actuating a timer valve 20 in the passage. A plug 30 is turned by its knob 92 to allow gas to flow via passage 36 and filter 40 to a closed pilot burner valve 192, Fig. 3. On depressing button 178, an electromagnet 152 and its housing 148 are moved downwards against spring 150 to make the magnet contact an armature 164 biased downward by spring 172 to hold the valve 22 closed, and a pin 204, Fig. 3 carried by the housing, moves on to a cam 210 on the armature stem whereby the pin opens the pilot 192. When the pilot burner lights, a thermo couple energizes the magnet which lifts the armature, on releasing the button, and allows spring 133 to open valve 22. Pin 204 remains on the cam 210 and keeps the pilot valve open. Should the pilot flame go out, the magnet releases the armature and closes valves 22, 192. A knob 100 is now depressed against leaf springs 136, 138 to move two diametrical fingers 108 out of slots 120 and on to two concentric helical cams 118 on a fixture 112 in the knob 92. The knob 100 and fingers are carried by a rod 90 which contact valve stems 74 and lifts valve 20 off its seat on the plug valve against spring 84. Knob 100 is now turned to move the fingers over the helical cams and wind up a clock movement 130 through spring 138 on rod 90 engaging spring 136 on a pinion 134. The plug 30 is now turned to full on position allowing gas to pass both timing and safety cut off valves to the burner. The clockwork returns the fingers along the cam until they re-enter their slots and close the valve 20 after a time interval determined by the rotation of knob 100. The relation between the strokes of the helical cams is such that a small torque is needed to move the fingers against friction of the cam and is independent of the axial thrust of rod 90.