GB1118372A - Improvements in cooking ovens - Google Patents

Abstract

1,118,372. Gas cooking ovens; controlling burners. R. & A. MAIN Ltd. 7 April, 1966, No. 15692/66. Headings F4T and F4W. The temperature of a cooking oven, heated by a gas burner 1, is controlled by a thermostat 18 which keeps the temperature in the range 150-550‹ F. for cooking and in the range 750- 950‹ F. for heat-cleaning of the oven walls. Waste gases pass through an opening 19 and duct 20 into a secondary duct 22 lined with refractory material 23 and heated to incandescence by a burner 25 disposed in an opening 24. The incandescent refractory 23 oxidizes the waste gases which then pass, through an opening 26, into an outlet duct 27, downstream of a Venturi constriction, so that cold air supplied by a fan 29 extracts and cools the cleaned gases. Gas supplied to burners 1 and 25 is regulated by a governor 44 and by mercury valves 37 and 38 actuated by pilot lights 33 and 34 acting on heat sensitive elements 35 and 35 respectively, glow coils 39 and 40 being used to ignite the pilot lights. The control system is such that either burner 1 alone, or burners 1 and 25 operate simultaneously, these conditions being achieved by using the appropriate setting on the oven control clock 45 and thermostat 18, the latter determining which glow coils and solenoid valves 31 and 32 are energized, these valves regulating the gass supply to the pilot lights. A heat-sensitive switch 42 closes at a pre-set temperature thus locking the oven door by causing a solenoid-operated bolt 43 to be shot.