METHOD TO DETECT MICROCONCENTRATIONS OF FLAMMABLE AND TOXIC GASES Russian patent published in 2015 - IPC G01N21/3504 G08B21/14 G08B21/16 

FIELD: measurement equipment.

SUBSTANCE: method includes penetration of infrared radiation via controlled volume on working and reference wave lengths. Wave lengths are chosen so that radiation on the working wave length is absorbed, and on the reference wave length is not absorbed by gas. As sources of radiation they use two semiconductor radiators, which operate in pulse mode. Radiation from sources is focused in the plane of the radiation receiver. Radiators are equipped with interferential filters to narrow the radiation spectrum band. Durations of pulses of working and reference radiation are equal to each other. The radiator on the working wave length is started by clock pulses from the generator directly, and the reference radiator is started with a time delay. Signals received from the receiver of radiation arrive to two amplifiers. At the same time the amplifier for the reference wave length opens with a delay. Outlet signals of amplifiers are compared by a comparison system.

EFFECT: increased sensitivity.

2 cl, 6 dwg, 2 tbl