| 摘要 |
A fuel supply and ignition control system for controlling the operation of pilot and main valves in an intermittent pilot type system. At the start of an ignition cycle, the pilot valve is operated to supply fuel to a pilot outlet for ignition by sparks generated by a spark generating circuit. When the pilot fuel is ignited, the pilot flame bridges the spark gap, and a flame sensing network, which is connected in circuit with the spark electrodes, generates a flame signal which is applied to an enabling circuit which responsively effects operation of the main valve. The enabling circuit includes a controllable switching device which in one embodiment, is maintained disabled in the absence of a flame signal and is enabled to cause a flame relay to operate and energize the main valve when a flame signal is provided. In another embodiment, the controllable switching device is enabled in the absence of a flame signal and causes an SCR device to conduct, providing a low impedance energizing path for the pilot valve operate winding and a shunt path around the main valve operate winding. When a flame bridges the spark gap, the flame signal disables the switching device so that the SCR device is rendered non-conducting, interrupting the shunt path around the main valve winding allowing the main valve to operate.
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