Optical smoke detector system - uses light beam with screen and lens system operating in air sampling chamber to measure optical density

摘要

An optical smoke detector comprises an internal sample chamber in which air carrying combustion products such as smoke is permitted to enter. A source of light generates a beam which is directed into the chamber to diffuse through the air sample. The sample chamber is provided with a screen on which the light beam permeating the gas sample is imaged. An output lens is arranged to transmit same of the light coacting with the screen and a detector of light furnishes warning signals under combustible condition.