METHOD AND DEVICE FOR SMOKE RECORDING Russian patent published in 1999 - IPC

FIELD: fire alarm. SUBSTANCE: method involves shaping periodic bursts of light pulses emitted into optical chamber provided with light-absorbing walls, receiving reflected signals arriving at angle other than that of optical emission axis both during emission of light pulses and at intervals between light pulses of burst, comparing with threshold value and memorizing them, followed by shaping smoke recording signal on condition that entire burst of light pulses has been received. Device has clock generator, reset circuit, control and memory circuit, optical chamber, photodetector, emitter, comparison circuit, output switching circuit, and noise detection circuit incorporating flip-flop, as well as AND and NAND gates functioning to implement this method. EFFECT: improved noise immunity in fire detection; improved design of device reducing probability of false operation. 2 cl, 2 dwg