| 摘要 |
PURPOSE:To obtain a detecting system having a high noise-prevention performance, by eliminating the effect due to fluctuation of impressed voltage in such a manner that a flame electric- current detecting circuit computes the ratio of impressed voltage and flame electric current to output it to a judging element, whereas combustion conditions and insulation capacity being judged separately by respective values of electric current in said judging element. CONSTITUTION:A flame rod sensor 3 for detecting combustion conditions of flames, an electric power circuit 7 which applies AC power between electrodes 4 and 5 of said sensor 3, a flame electric-current detecting circuit 6 for detecting electric current passing through the sensor 3, and a judging element 20 which judges combustion conditions of flames by the output of the circuit 6, are provided. The circuit 6 comprises a standard voltage element 11 for producing output in proportion to the voltage impressed on the sensor 3 from the circuit 7, an electric-current measuring element 10 for delivering output in response to electric current passing through the sensor 3, and an operational element 12 which computes the ratio of these values of output to be delivered as output. Furthermore, the judging element 20 is composed of a plus electric-current judging element 22 for judging, synchronizing the circuit 7, the value of flame electric-current when voltage is impressed on the sensor 3 in plus direction and a minus electric-current judging element 23 for judging the value of flame electric current when voltage is impressed in negative direction. |
