Abstract: A system for automatically detecting fires fueled by hydrocarbons and certain non-organics including hydrogen, hydrazine, magnesium, aluminum, potassium, ammonia and silane, which system has a low incidence of false alarms from incident radiation emitted by non-fire radiation sources such as the sun. The system includes a UV sensor assembly that both senses UV radiation in a predetermined spectral bandwidth and generates a first signal corresponding to the sensed radiation; an IR sensing assembly consisting of a single IR sensor that simultaneously senses IR radiation in two predetermined spectral bandwidths and generates a second signal corresponding to the IR radiation in at least one of the spectral regions; and a signal processor. The UV spectral bandwidth is such that the UV sensing assembly is responsive to UV radiation emitted by hydrocarbons and certain non-organics but non-responsive to solar UV radiation.

Abstract: An automatic fire detection system characterized by an extremely low incidence of false alarms utilizes two detection channels, one fed by an infrared (IR) detector and the other by an ultraviolet (UV) detector. Signal processing electronics in each channel produce a normalized output signal proportional to the power of incident IR and UV radiation within specific bandwidths. The system features a ratio detector that repeatedly forms a ratio of the normalized IR and UV inputs and compares the ratio to a known range of values for this ratio that are characteristic of a fire. A discriminator connected to the output of the ratio detector generates a fire alarm signal only if the majority of these ratio comparisons are fire-indicating. The system also includes a feedback loop in the IR processing channel that automatically adjusts the output of the channel to compensate for time-varying background IR radiation such as sunlight.

Abstract: An overtemperature detection cable for use with a fire alarm system, a fire extinguishing system or the like comprises a coaxial assembly of an inner spring wire conductor in a core of thermoplastic dielectric material within an electrically conductive outer sheath. In one embodiment, the spring wire is initially coiled in a three-dimensional helical configuration, is thereafter uncoiled to approximate a straight wire, and is then disposed within the outer sheath to reside in the thermoplastic dielectric core. In a second embodiment, a straight inner spring wire and its surrounding thermoplastic dielectric core reside within an outer sheath, and the assembled sheath, wire, and thermoplastic dielectric material are then bent or crimped to assume a two-dimensional sinusoidal configuration.