GB601739A - Improvements in or relating to safety control and ignition systems for gaseous fuel burners - Google Patents

Abstract

601,739. Gas burners. ELLIS, L. S. E. (Robertshaw Thermostat Co.). Oct. 5. 1945, No. 25998. [Classes 75(i) and 75(iii)] f Also in Group XXIX] In a safety control system for a main gas burner 10 and pilot burner 44 the closing of a main switch 78 completes the circuit through an initially closed switch 84 to the primary coil 64 of a transformer 60 and thereby energises a pilot burner igniting coil 69 and operates electromagnetically a plunger 62 to raise the stem 31 of a valve 16 against the resistance of springs 26, 34. In the raised position a member 50 on the stem prevents gas from passing to the burner 10 but gas can pass through a conduit 46 from the valve opening 20 to the pilot burner 44. In addition a collar 41 on the stem raises an armature 38 into contact with the pole faces of an electromagnet 36 and completes at contacts 94, 96 a circuit to a heating coil 88 around a bimetallic operator 86 for the contacts 80, 82 of the switch 84. If the pilot burner has been ignited a thermocouple 52 adjacent its flame supplies current to the electromagnet 36 to hold the armature in position with the contacts 94, 96 closed before the operator 86 separates the contacts 80, 82. When this separation occurs the transformer circuit is broken and the stem 31 drops until a collar 40 spaced above the collar 41 engages the armature 38 in which position gas passes to the main burner 10. If flame failure occurs the armature 38 drops and the valve 16 closes, recycling occurring after the operator 86 has cooled. The main switch 78 may be manually or thermostatically operated either independently or in conjunction with a main gas valve 14.