Combination visible light detector and ultraviolet detector coacting as a fire discrimination system

Claim 1

A combination visible light detector and ultraviolet detector coacting as a fire and explosion discrimination system for a preselected area under surveillance comprising a broad band solar cell detector permanently operative, an ultraviolet detector normally inoperative and becoming operative upon the receipt of a preselected high AC voltage, said broad band solar cell detector and said ultraviolet detector being physically and electrically positioned to simultaneously survey said preselected area, said broad band solar cell detector upon sensing visible light characteristic of flame and explosion emanating from said preselected area providing a first electrical signal, means to generate a gating signal upon receipt of said first electrical signal, a DC to AC converter arranged to be energized upon receipt of said gating signal to provide an AC output voltage thErefrom, said DC to AC converter also receiving a DC input voltage, means to generate said preselected high AC voltage for said ultraviolet detector upon said receipt of said AC output voltage, said ultraviolet detector upon becoming operative detecting the presence of any ultraviolet component in the sensed visible light characteristic of flame and explosion to provide a second electrical signal, and an alarm circuit becoming operative upon the receipt of said second electrical signal.