| 摘要 |
PURPOSE:To attempt to perform fail safety of electronic parts to improve safety and reliability of the controller by varying the reference signal of a flame current at a desired frequency by reference signal varying means and energizing a fuel supply device when a flame detecting signal exists. CONSTITUTION:The controller comprises a flame current detection means, reference signal generating means 28, comparison means 27 concurrently used as flame current limiting means 32 using a J-FET36, reference signal varying means 29 for varying the reference signal at a desired frequency, AC coupling means 30 controlled by the output of comparison means 30 and a fuel supplying device 31. When the impedance Rf of a flame 11 becomes smaller than a predetermined Rfs, the oscillation frequency f0 of a multivibrator transmits a signal to a transformer 51 through the ON-OFF operation of the J-FET36, and the fail safety of electronic parts is positively performed and an electromagnetic valve 10 is energized by the output of the transformer 51, and hence the safety and reliability of the control device can be improved. |
