Poretech Instrument Inc. products

In order to detect extremely low gas transmission rates through a sample, it is necessary to abandon direct flow measurement because flow meters are not very accurate. Diffusion Permeameters determine the low gas flow rates indirectly by measuring time rate of change of pressure on the outlet side. The sample was loaded in the sample chamber which divides in two chambers. One chamber is on the inlet side of the sample and the other is on the outlet side of the chamber. The exact volume of outlet chamber is determined. The chambers on both sides of the sample are evacuated. Then a quantity of test gas is introduced to the chamber on the inlet side of the sample, its pressure is kept almost constant, and the pressure is monitored on both sides of the sample. The two pressures are recorded as functions of time. The data are used to compute transmission rate. In order to obtain the utmost accuracy, the system is maintained at a constant temperature.

The test methods cover the determination of water vapor transmission (WVT) of materials through paper, plastic films, PTFE membrane and other sheet materials. Test dishes filled with distilled water in a controlled dry atmosphere, a constant humidity difference is generated between two sides of the test specimen, the water vapor permeates through the specimen and into the dry side, water vapor transmission rate and other parameters can be obtained by measuring the weight changes of the test dish in different time.

AOPT-301 is based on the coulometric sensor method and is available for the OTR testing of flexible films, sheeting and packages. It can test 3 specimens in one operation with independent results.

The Darcy’s Law Gas Permeability Analyzer is a computer-based automatic test machine that can be used to analyze the performance of a porous media, such as membrane, non-woven, ceramic, fabric…