SUXlMXRY
A new procedure for measuring the hydrodynamic permeability of fine pore capillary systems is described. The main advantages of this procedure as compared with the methods described in the literature are as follows:
The appropriate design of the membrane holder excludes damage of the membrane at the clamped edges and the filtering area is constant and well defined even after repeated clampings.
The measurement of volume flow through the membrane is refined so that small volume displacements can be accurately measured. Therefore our method permits the use of small pressures, thus avoiding the need for a membrane support which may, through covering part of the filtering area, lead to errors. Hence pressure deformation and damage to the membrane are eliminated as well. Further, with this method, small discontinuities in volume flow through the membrane can be recognized and measured.
REQU1REMWl-S FOR THE DESIGN OF THE MEASURING APPARATUS
The pressure dependence and the clogging effect have been previously described by us and other authors (26-35), but no practical conclusionsas regards Desalination, 6 (1%9) 203-214