You can use the WDDG to determine the WVTR (of up to 10 g/m2 d) for your specimen.
The sample is put between the top and bottom part of the permeation cell. A constant water-vapour pressure (RH) is adjusted in the upper part of the permeation cell using saturated saline or defined sulphuric acid solutions. The carrier gas (nitrogen 5.0) is pre-dried inside the WDDG. Then the carrier gas is fed into the bottom part of the permeation cell. The flow of carrier gas absorbs the water vapour that permeats through the sample and transmits it to the Keidel electrolytic cell. There the amount of water vapour is quantitatively recorded. The electronic system registers the current and displays the WVTR directly in the corresponding unit (grams of water as per square meter and day) using a 7 segment display.
The test duration depends on the WVTR of the inserted specimen. At the beginning of the test the displayed value continuously increases. You can track this increase of the WVTR with a plotter. As soon as the procedure has reached the final value (no further increase), you can stop the test.
You can adjust the sample temperature within the range of -25°C and 60°C using an external