| 摘要 |
PURPOSE:To enable stable control of combustion even at the time of switching a set voltage in response to a flame detection signal by set voltage switching means in a combustion controller of a proportional combustion system by employing a semiconductor switching element instead of a relay contact as the switching means. CONSTITUTION:Transistors Q1, Q2 are controlled only when they receive flame detection signals F, F' which are generated by flame detectors (not shown), and when an ignition operation is performed, both the transistors become ON. At this time a power source voltage is applied through resistors R6, R7 via the first setting circuit as the first set voltage to an amplifier 1, and the output signal of a level adapted for the ignition operation is produced from an output terminal 2. On the other hand, when the flame signals F, F' are inputted and the transistors Q1, Q2 become OFF, the second set voltage set via a variable resistor VR1 is applied instead of the set voltage to the input terminal of the amplifier 1, and the output signal of the level adapted for the ordinary combustion is produced from an output terminal 2. |
