OPTICAL GAS-CONCENTRATION DETECTING METHOD AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an optical gas concn. detecting method and an apparatus therefor capable of detecting not only a component having an infrared absorption spectrum but also a component having no infrared absorption spectrum. SOLUTION: A part of laser beam having a specific wavelength is passed through a gas atmosphere to be measured and other part thereof is not passed through the gas atmosphere to be set to reference beam and the respective beams are received and the concn. of gas absorbing laser beam having the specific wavelength is detected from the difference between the beam transmitted through the gas atmosphere and the reference beam and a part of the beam transmitted through the gas atmosphere is passed through a waveguide sensor 9 changed in its beam transmission characteristics by the adsorption of specific gas and the concn. of the specific gas is detected from a ratio of the beam transmitted through the waveguide sensor and the beam transmitted through the gas atmosphere.