Patent ID: 7229593

Claim:
An apparatus for measuring an effective vapor diffusion coefficient of a test vapor diffusing through a porous test media, comprising: a test chamber comprising a hollow cylinder made of a gas impermeable material, for holding a sample of porous test media having a length=L, the chamber comprising an entrance and an exit; source means, fluidically connected to the entrance of the test chamber, for introducing test vapor into the test chamber; sensor means, fluidically connected to the exit of the test chamber, for measuring time-varying concentrations of test vapor after the test vapor has diffused the distance, L, through the sample of porous test media disposed inside the test chamber; and data processing means for recording measured time-varying concentrations of test vapor and for calculating an effective vapor diffusion coefficient of the test vapor diffusing through the porous test media; and further wherein said source means comprises a source chamber connected to the entrance of the test chamber for holding a source of a volatile substance, and further comprising a movable partition disposed in-between the source chamber and the entrance to the test chamber for controlling the flow of vapor from the source chamber into the test chamber.