GB1493580A - Gas-burning appliances - Google Patents

Abstract

1493580 Burner controls UNITED GAS INDUSTRIES Ltd 17 Dec 1974 [22 Dec 1973 9 Feb 1974] 59687/73 and 6008/74 Heading F4T A control for a gas burning heating appliance (fire &c.), of the kind having a fan 11 for supplying combustion air, and a pilot burner for igniting a main burner, the control providing a stand by condition in which the air fan runs at a reduced speed and the pilot burner, but not the main burner, is operating. In operation, a control knob Fig. 2 is moved toward the "PUSH FOR PILOT" position, whereupon switch S5, Fig. 1, closes so as to supply current to a speed reducer 18 to drive the combustion fan at 25-30% of its full speed. The knob is pushed down to close switches S1, S2, pilot fuel valve 13 is opened, ignition circuit 24 is made, and the pilot burner is ignited. A flame detector 37 supplies a signal through an amplifying circuit 35 to activate a silicon-controlled rectifier 34 and a neon light 36. The knob is now released to thus open switches S1, S2, which cuts off circuit 24, but rectifier 34 maintains a circuit for valve 13 for so long as a flame is detected. This is the "stand-by" position when heat is required, the knob is turned to "FULL ON" position so that switch S3 is closed, which causes the main fuel valve 14 to open, provided a thermostat switch 30 and a time-controlled switch 31 are closed. A relay 32 is operated to close a switch 19, so that speed reducer 18 is bypassed and fan 11 runs at full speed, and simultaneously a switch 21 is closed so as to start a convection fan 12. The main burner is lit by the pilot, but if either of the switches 30, 31, is opened, valve 14 closes, relay 32 allows switch 19 to open and fan 11 returns to the slow running condition, and when switch 21 opens fan 12 stops. Switch 21 may be a thermostat or like heat sensitive means, and reducer 18 may be a resistor or a diode or a combination of these. In a modification Fig. 3, pilot burner 41 is ignited to heat a temperature sensitive circuit phial 45 which sends a signal to ignition circuit 24 inhibiting it from producing further sparks. Switch SW3 is operated to open the main gas valve 14, whereupon a relay 46 is energized to cause switch SW2 to short circuit speed reducer 18 and combustion air fan 11 runs at full speed. Gas line 40 supplies gas in series to pilot valve 13, main valve 14 and pilot and main burner 41, 42.