Color indicator composition for gaseous carbon dioxide, used with gas purification system for purifying bottled gas for operating equipment or calibration in analytical laboratory, contains metal hydroxide and pH-indicator dye

摘要

Color indicator composition (I) for gaseous carbon dioxide (CO2) contains a metal hydroxide (II) and a pH-indicator dye (III). Independent claims are also included for the following: (1) Gas purification system for CO2 containing (I). (2) Indicator system for showing CO2 in a gas, comprising indicator cartridge(s) with (I). (3) Gas purification process using the gas purification system. (4) Method of identifying exhaustion of the capacity of a CO2 gas purification or absorption composition in a purification cartridge in gas purification by placing an indicator unit with (I) in series or parallel to the purification cartridge in a separate, partly or completely transparent housing. (5) Use of barium hydroxide, colored with bromothymol blue, as color indicator system for CO2.