Flow gas permeameter for determination of the transport parameters of gases and water vapours through flat polymeric membranes

The apparatus for determination of transport parameters, viz. permeability and diffusion coefficients of gases and water vapours through flat polymeric membranes, was constructed. A new construction of a permeation cell in the unit with an operating valve of sample gas makes possible to measure the time dependence of diffusion process more reliably and with higher accuracy. The sensitivity and rate of response of thermal conductivity detectors were also increased by the new arrangement of electronic circuits. The connection of apparatus with a computer increases the productivity and reliability of measurement and provides a fast evaluation of experimental data. The apparatus, based on the differential permeation method with the conductivity detection of the composition of gaseous mixture by thermistors, has been calibrated for CO2, O-2, N-2, and water vapours at 25 degrees C. The precision of determination of permeability coefficients is about 12 % in average; the values of diffusion coefficients can be determined with accuracy better than 10 %.