Some techniques for investigating the unsteady‐state molecular flow of gas through a microporous medium

An experimental method has been developed which is capable of measuring the unsteady-state molecular flow of small volumes of gas from a micro-porous solid such as are encountered under thermal conditions unfavourable to adsorption. Two new computational procedures, which do not use the severe simplifying assumptions of existing methods, are described for evaluating diffusivities from unsteady-state diffusion data. They are applied to some experimental results on the diffusion rates of several gases from synthetic zeolites.