A critical analysis of capillary flow porometry with regard to its application to non-woven fibrous filter media

H.E. Kolb*, R. Schmitt, A. Dittler, G. Kasper, Karlsruhe Institute of Technology (KIT), Germany

Capillary flow porometry is a well-established technique for measuring pore size distributions in polymer membranes and fibrous media within a useful range of typically about 1 to 50 µm. Its operating principle is based on saturating small samples of the media completely with a wetting liquid, and then progressively “blowing out” pores with air by increasing the differential pressure ∆p across the sample. From the attendant increase in volumetric flow rate (or flow velocity) through the sample one can then derive a !@#$%^&* pore size distribution. Being a flow-based method, capillary flow porometry is quite attractive to characterize porous media used for filtration; it is often preferable to purely geometric or tomographic techniques and also less !@#$%^&*. Porometers are thus available commercially, and ASTM F316 describes their use for “non-fibrous membranes”. Despite their wide-spread use for fibrous media, one is hard-pressed however to find a critical analysis in the scientific literature regarding their fundamental reliability.

Experimental results will be reported on commercial glass microfiber media, which were evaluated with 3 commercial porometers as well as an inhouse-designed device. Parameters such as the wetting liquid, the sample diameter, the scanning speed, and the sequence of operation were varied. The results will show...

Session: F2 - Filter Media - Quality Control and Pore Size Analysis II
Day: 13 March 2018
Time: 14:45 - 16:00 h

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