| 摘要 |
PURPOSE:To eliminate false operation by generating a flame detection signal at the time when the brightness distribution of a flame is detected by two sets of photoreceiving elements and further when the difference between output signals of each group of photoreceiving elements exceeds a fixed level. CONSTITUTION:A tubelike casing 2 is fitted with a lens 1, while inside the casing 2 is housed a detection unit 4 supported by a print plate 3. The detection unit 4 consists of an integrated circuit having a photoreceiving part 5 in the front thereof and is arranged so that the photoreceiving part 5 corresponds to the surface whereon the flame is imaged by the lens 1, while the output signal of the detection signal 4 is taken outside by a cable 6. Between the terminals A and B of the photoreceiving part 5 is provided a variable resistance VR for adjusting balance, and the current signal generated at the terminal 11 is converted into a voltage signal by the action of the resistance R1, unnecessary low-frequency components are removed therefrom by a highpass filter 12, and then the signal enters an amplifier 13 and further is supplied to a switching circuit 14. The detection signal comes out from the switching circuit 14 to the terminal 15 only when the output signal level of the amplifier 13 exceeds a set value. |
