Method and apparatus for determining the concentration of a gas or gases in a gas mixture by sensing the coloration undergone by reagent test paper, or the like, in response to exposure to such gas or gases

摘要

The concentration of gas is determined by monitoring the coloration of a reagent test paper, or the like, whose color changes progressively or otherwise in response to continued exposure to such gas. The concentration is determined by determining the length of time which the reagent test paper must be exposed to the gas for the coloration of the test paper to reach a preselected threshold value.