| 摘要 |
PURPOSE:To certainly detect a flame without generating erroneous operation due to noise, by discriminating a flame when the difference of the amplitude value of the plus change portion and that of the minus change portion in flickering change is within a range from a first threshold value to a second threshold value set so as to be higher than the first threshold value. CONSTITUTION:The light energy from a flame 1 is incident to a flickering change detection means 3 through an optical apparatus 2 and the detection means 3 outputs a detection signal to an AC amplifying circuit 6. The circuit 6 amplifies the flickering frequency from the flame 1 to outputs the same to an A/D converter circuit 7 which, in turn, applies A/D conversion to this equal to output the converted signal to a flame discrimination part 9 through an input/output interface 8. The flame discrimination part 9 decodes the detection signal from the detection means 3 and discriminates the flame when the ratio of the amplitude of the plus change portion and that of the minus change portion in flickering change is within a range from a first threshold value to a second threshold value set so as to be higher than the first threshold value. A signal is outputted to an alarm circuit 10 through the interface 8 to order alarm display. |
