High-shear turbulent flow filtration for chemical monitoring of pulp and paper process waters

In this study, we report the development and performance of a system for th e continuous withdrawal of a fluid sample not containing coarse fibres (>10 mu m) from a paper furnish slurry in order to obtain a sample for analytic al purposes. A consistent filtrate, containing colloidal material, was obta ined by preventing cake formation on the filter surface. This was accomplis hed by generating high shear forces at the filter surface while withdrawing very low sample volumes. The use of track-etched membrane filters was a ke y factor in the prevention of filter fouling. The filtration apparatus test ed performed continuously for over one week without filter fouling or damag e.