ULTRA-SHORT WAVELENGTH PHOTOELECTRIC SMOKE DETECTOR

摘要

A photoelectric smoke detector incorporates a short wavelength radiant energ y emitter (14). The emitter, an LED or laser diode, emits frequencies in a ran ge of 430 to 450 nanometers. The emitted frequencies can be further shortened b y directing them to impinge on a non-linear crystalline material (22). Radiant energy emitted from the material will have a wavelength on the order of sixt y percent that of incident radiant energy (14'). The short wavelength energy will be scattered by airborn particulate matter characteristic of relatively fast, flaming fires. The emitter, an LED or laser diode can include an 880 o r 940 nm wavelength coupled with shorter wavelength ranges (190-450 nm) with associated detection. It also has the capability of detecting slow burning smoldering-type fires. A control circuit and an audible output device provid e a local audible alarm of a detected fire.