| 摘要 |
In the method and the device for testing the permeability of membrane filters, the moistened membrane filter is exposed to a predetermined test-gas pressure on the feed side in a first closed system and the pressure change in the closed system with time is measured. In the test methods hitherto known, the pressure at which the diffusion-gas stream became a combined diffusion- and conduction-gas stream through the membrane to be tested could be determined only inaccurately and with difficulty. The object of the invention is a more sensitive test method with which the permeability and, consequently, the pore size of a membrane filter can be determined solely from measurements on the feed side of the membrane filter. This is achieved by bringing a reference-pressure system to the test-gas pressure at the beginning of every measurement and by measuring the pressure change in the form of the pressure difference between the first system and the reference-pressure system.
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