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Method and apparatus for fuel ignition system including complete cycling of flame relay prior to trial for ignition
Method and apparatus for fuel ignition system including complete cycling of flame relay prior to trial for ignition
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机译:用于燃料点火系统的方法和设备,包括在点火试验之前完成火焰继电器的循环
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摘要
When a call for heat is established, a flame relay is actuated for a predetermined time by means of a cycling timer. Upon this initial actuation, the flame relay inhibits a checking relay and initializes a trial-for- ignition (or simply "ignition") timer. After the cycling timer times out and the flame relay has been completely cycled, which established operativeness of the flame relay and flame sensing circuitry, the checking relay is enabled and actuated for the ignition period. The checking relay then actuates the pilot valve and a spark generator to start a pilot flame. If a flame is sensed, before the ignition timer times out, the flame relay actuates the main valve and establishes a holding current for the ignition timer so that the checking relay continues to be energized. If a flame is not sensed during the trial period, the ignition timer disables the checking relay, thereby de- energizing the pilot valve before the main valve is opened. If there is a fault in the flame relay or flame sensing circuitry, the checking relay is inhibited from operating. Both timers are preferably electronic timing circuits using capacitors in such a manner that circuit faults do not cause system malfunction. In an alternative embodiment, separate flame sensing circuits control the operation of the flame relay and the ignition timer.
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