ABSTRACT
The dynamic method of generating gas and vapor mixtures requires the uninterrupted blending of the component parts for some specified period of time. This technique enjoys many advantages over static methods and is especially useful in producing reactive gas mixtures. If the mixture is prone to decomposition or chemical reaction, the undesirable reaction products can be swept away and continually replaced by the relative pure and unreacted test gas mixture. Large volumes of concentrations from 50% down to the parts per billion range can be controlled and altered easily with convenient, compact equipment. Wall adsorption, a problem with most static systems, usually becomes negligible, since an equilibrium is established after operating for a long enough time period. However, these general advantages are sometimes offset by the cost and complexity of many dynamic methods, especially those required for producing parts per million and parts per billion mixtures from pure starting materials.
