A LOW-COST GAS MIXER

A low cost gas mixer for permanent gases and volatile agents is described. The apparatus uses the simple principle that if known volumes of gases are mixed at the same pressure and temperature, then a mixture of known composition results. The apparatus is shown to have an accuracy of better than ± 0.08% vol/vol for gases and volatile agents in two and three part mixtures. For permanent gases the mixer could be used accurately over the concentration range 1-99% vol/vol. For volatile agents the mixer was suitable for mixing concentrations in the low percentage ranges (< 5% vol/vol). Gas mixtures, including volatile agents, could be stored in the mixer for approximately 2 h without changes in concentration outside this limit of accuracy. © 1990.