| 摘要 |
PURPOSE:To detect only either fire selectively by paying attention only to the light emission wavelength of a chemical species that fires feature and monitoring a change in the lapse of time in light emission intensity or a light emission intensity value of each wavelength, etc. CONSTITUTION:A light beam sampled by a fire flame sampling head 6 is inputted to an interference filter 7 through an optical fiber 13. The interference filter 7 transmits only a light beam required for selective fire detection. Then, a filtered light beam is guided to a photodetector 8 through the optical fiber 13 and converted into an electric signal 14, which is monitored by a time-wise judging circuit 11 with time through an amplifier 9 and an integration circuit 10 and the compared with a set value. For example, the integral value of the light emission intensity of 3,880Angstrom generated by the secondary fire occurrence after an ignition time t0 is comapred with a set value and a fire detection signal is generated at time t1 when the integral value exceeds the set value. Then the electric signal 14 is transmitted to a fire occurrence judging circuit 12 to judge whether a fire occurs or not. |
