Kaasun pitoisuuden mittalaitteisto ja menetelmä

This publication discloses an apparatus and method for measuring a gas content. The apparatus includes a light transmitter ( 1 ), by means of which coherent light can be sent to the measurement object ( 3 ), a receiver ( 2 ), by means of which light that has passed through the measurement object ( 3 ) can be detected, and optical means ( 4, 5, 6 ), by means of which the light intensity of the light transmitter ( 1 ) can be aimed at the receiver ( 2 ). According to the invention, the optical means include a lens element ( 4 ), the optical axis of which is arranged essentially obliquely relative to the longitudinal axis of the measurement object ( 3 ), so that the angles of the normals of the optical boundaries relative to the measuring signal are set obliquely. The lens element ( 4 ) is both a refracting and a reflecting element, and separates the measurement object ( 3 ) from the means ( 1, 2, 5 ).