Dual channel multi-spectrum infrared optical fire and explosion

Abstract

A fire detection system including two optical sensing channels and signal processing circuitry that processes the two sensing channels' output signals and generates another output signal when the processed signals are indicative of a fire. The system automatically detects hydrocarbon and certain non-hydrocarbon fueled fires. The first sensing channel simultaneously senses IR radiation in two IR spectral regions having separate and distinct bandwidths and generates a first signal corresponding to incident IR radiation being sensed in at least one of these spectral regions. One bandwidth is selected so the first sensing channel is responsive to the IR radiation emitted by hydrocarbon and/or certain non-hydrocarbon fueled fires and the other bandwidth is selected so the first sensing channel is responsive to IR radiation emitted from hydrocarbon fueled fires. Both bandwidths are selected so the first sensing channel is essentially non-responsive to solar IR radiation. The second sensing channel simultaneously senses IR radiation in three IR spectral regions, defined by separate and distinct bandwidths, and generates a second signal corresponding to the incident IR radiation being sensed in at least one of the these spectral regions. Each second channel spectral region bandwidth is selected so the second sensing channel is responsive to IR radiation emitted by non-fire radiation sources but non-responsive to IR radiation in the first channel spectral regions.