| 摘要 |
PURPOSE:To detect an oxygen shortage state very sensitively by using a current which flows by the existence of a flame between electrodes (a flame current) as an input signal and from the decrease of this flame current. CONSTITUTION:An alternate voltage is applied to a burner body, and if a flame exists between combustion state detecting electrodes, a flame current flows to an input end 8. An input signal from the input end 8 first passes a current setting circuit 1 and is amplified to a voltage signal by an amplifying circuit 2. Then the signal amplified to the voltage signal by the amplifying circuit 2 is branched on one side, this signal value is attenuated by a specified percentage, then passed through an analog-digital conversion circuit 4 and stored in a memory circuit 5. On the other side, this signal value is not changed, and passing through an analog-digital conversion circuit 3, inputted to a comparison circuit 6. And the comparison circuit 6 compares an input signal value during combustion with the stored value in the memory circuit 5, and if the two signal values coincide with each other, an oxygen shortage signal is outputted from an output end 9. |
