GB1074382A - - Google Patents

Abstract

1,074,382. Burner control systems. HONEYWELL Inc. June 11, 1964 [June 12, 1963], No. 24324/64. Heading F4T. A fuel burner control system has a programme timer to give a purging time prior to ignition, a main burner ignition period, and a running period and is also provided with a manual switch which can only operate during the purging period to stop the timer to enable adjustments to be made to the burner system. When the START switch 27 is closed, current flows through the normally closed timer contacts T2 and contacts 2R1 through the heater 32ofthesafetyswitch,thelowerpart 30of the relay 1R, the contacts 34, 39 back to the other supply line 23. Energization of relay 1R closes contacts 1R3 to complete the circuit through contacts T9, manual switch 41 to start the timer motor and to energize the relay 3R to close contacts 3R1 which complete the circuit to the fan 13 and provide purging. The closing of contacts 1R1 by the relay 1R provides a holding circuit for this relay through the STOP switch when the START button is released. After a given time interval the timer contacts T5 are closed and the completion of a circuit through the STOP switch, previously closed contacts 1R2, closed contacts T8 energizes the ignition transformer 17 and pilot fuel valve 15 to light pilot burner 12. If a flame is established the sensor 26 operates the flame detector 20 to energize the relay 4R, thus closing the contacts 4R1 to energize the secondary flame relay 2R, thereby opening contacts 2R1 to disconnect the heater 32 in the safety switch, and closing contacts 2R3 to shunt contacts T8 and closing contacts 2R4 to open the main burner fuel valve 14. After a suitable interval timer opens contacts T5 to switch-off pilot ignition and valve. Should a pilot flame not be established the main burner will not be operated and the current through the heater 32 in the safety switch will cause the lower end of the bimetal 33 to release the pivoted switch arm 36 to open contacts 34, 39, and shut-off the pilot burner ignition system and complete the circuit through contacts 38, 35 to the alarm.