Abstract: A flame detector consisting of a first infrared radiation detector for detecting radiation from combustion of hydrocarbon and other carbon containing compounds in conjunction with a second infrared radiation detector for distinguishing radiation from other sources such as modulated sunlight, reflections, artificial as well as natural hot objects, illuminating light sources, and arc welders. The flame detector uses two electronic circuits following the first infrared detector such that a fire is sensed by either of the two circuits depending on its size, one circuit being optimized for flicker frequencies present in a large fire while the second circuit simultaneously checks for optical signals at flicker frequencies dominant in a smaller fire. The two electronic outputs along with the output of the second infrared detector are digitally processed and analyzed for spectral and temporal characteristics to distinguish the presence of a real fire from that of various false alarm sources.

Abstract: Apparatus for the optical detection of selected toxic gases, using the ultraviolet region of the electromagnetic spectrum, and the known absorption properties of the toxic gases in the ultraviolet region. An ultraviolet flashlamp source illuminates a straight, highly polished metal tube with numerous perforations to permit access for the gas to be detected. The ultraviolet light then enters an optical compartment comprising an optical beamsplitter and two ultraviolet detectors with wavelength selective narrowband filters attached. The filters are selected so that one overlaps the region of absorption by the gas while the second is in a region where there is no absorption by the gas. The electronic circuit following the ultraviolet detectors and the drivers for the flashlamp, are timed by a microprocessor that provides the means for the electronics and data processing to be synchronized with the flashlamp pulse.