Gas analyzer

Abstract

A gas analyzer for measuring the concentration of a gaseous component in a test gas includes first and second separate cells adapted to alternately be filled with a test gas containing a gaseous component to be analyzed and a standard gas, light sources for directing rays of energy through the first and second cells and through the test gas and standard gas alternately contained therein, a detector positioned to receive the rays of energy after passage thereof through the first and second cells for detecting the concentration of the gaseous component within the test gas, and a changeover device connected to the first and second cells and adapted to be connected to sources of the test gas and the standard gas for alternately supplying the test gas and standard gas, at fixed intervals and in fixed amounts, into the first and second cells. The changeover device includes a single block having therein first and second inlets adapted to be connected to the source of test gas and the source of standard gas, respectively, first and second outlets respectively connected to the first and second cells, and a rotary valve rotatably movable between a first position respectively connecting the first and second inlets with the first and second outlets and a second position respectively connecting the first and second inlets with the second and first outlets.