Method and apparatus for determining the gas diffusion rate through membrane filters to test the permeability of membrane filters from the inflow side

摘要

In this method, the inflow side of the moistened membrane filter is first exposed to a first test-gas pressure in a first sealed system and then the pressure change is measured per unit of time. The first system is then brought to a second test-gas pressure, the total pressure change in the first system is determined over a predetermined measurement time and, finally, in addition to the pressure change brought about by the passage of gas through the membrane filter, an additional pressure change is brought about in the first system during said measurement time by releasing a predetermined amount of gas from the first system.