Patent GB-667033-A (GB)
Title: Improvements in control apparatus for fluid fuel-burning appliances
IPC: F23N5/10
Filed: 1949-06-23
Abstract: 667,033. Thermally-actuated valves. ROBERTSHAW-FULTON CONTROLS CO. June 23, 1949, No. 16765/49. Class 135 [Also in Group XI] Control apparatus for fluid fuel burning appliances having a main burner and one or more pilot burners comprises a main rotary shut-off valve 20 controlling the fuel supply to the burners and adapted to be operated by means, e.g. a rotary dial 34, requiring initial axial movement relative to the valve 20, the said axial movement actuating mechanical means to allow passage of fuel to the pilot burner or one of the pilot burners through a safety control valve 88 located remotely from the valve 20 and adapted to cut off the supply of fuel to the main burner 10 in the event of flame failure, the said mechanical means being caused to return to an inoperative position after a predetermined period by a device, e.g. a bimetallic element 182, responsive to the flame at the pilot burner 132. The stem 30 of the valve 20 has a collar 50 to which is secured a tube 40 biased outwardly by a spring 54 and having a flange 42 engaging in a slot 44 in the end of a tube 36 to which the dial 34 is secured, and, when the valve 20 is closed, in a slot 46 formed in an end member 32 of the valve housing. To open the valve 20 the dial 34 is pressed inwardly to release the flange 44 from the slot 46 and the stem 30 is turned clockwise to align openings 26, 28. Fuel may then pass from a manifold 14 through a pipe 29 and openings 28, 26 to an outlet 76, and past a valve member 64 to an outlet 72, the outlet 76 being connected by pipes 78, 138 with an auxiliary valve chamber 142 in the control device 88 and by pipe 78 to a pilot burner 74, and the outlet 72 being connected by a pipe 18 to the main valve chamber 94 in the control device 88. The valve member 64 is carried by a stem 61 rotatable through a pin and slot connection 62 by a shaft 60 secured to the valve stem 30, and is moved off its seat by a spring 86 on clockwise rotation of the stem 30 when an extension 68 of the stem 61 is screwed further into a cap nut 69 which is held against rotation but is allowed to move axially. The setting of the valve member 64 is controlled during operation of the main burner by an oven thermostat 84 associated with a diaphragm 80 engaging the cap nut 69. On the initial inward movement of the dial 34 a pin 204 actuates a member 200 slidably mounted in a bracket 194 to tilt a lever 192 pivoted on the bracket 194 and secured to a rod 186 which rotates pivoted members 172, 174 so that the bimetallic element 182 moves into alignment with the axis of the control valve 88. The latter is of a construction similar to that described in Specification 624,742, [Group XI], and is actuated by the movement of the bimetallic element 182 to allow fuel to pass to the pilot burners 130, 132, and a burner 160 for heating a thermocouple 158. The burners 130, 132, 160 are ignited from a constant burning pilot-flame 12 through flash tubes 162, 136, and the pilot flame 74 is ignited from the burner 160. Passage of fuel to the main burner 10 through the pipe 18 is prevented by a valve disc 106 until the latter is moved when the bimetallic element 182 has heated sufficiently to snap back into its original position. When this occurs the fuel supply to the pilot burners 132, 130, 160 is cut off, but the supply to the main burner 10 is permitted and is controlled by an electromagnet 122 energized by the thermocouple 158, heated by the pilot flame 74, which holds a second valve member 102 open unless flame failure occurs. The pilot burner 74 may, alternatively, be omitted, the thermocouple 158 then being heated by the main burner 10. Specification 625,696 also is referred to.