Fine mist filtration by wet filters—III: Sintered disc filters

Abstract

Sintered glass discs have been studied as collectors for dense mists of approx. 1 μm particles. The liquid saturation (holdup) attained when the rate of drainage equals the rate of collection agrees approximately with a literature correlation for thin beds of loose packing materials. Correlations are presented for the filter resistance caused by collected liquid. Plots of collection efficiency against flow velocity show a pronounced minimum. The behaviour of these plots under various operating conditions can be interpreted in terms of diffusion, impaction and direct interception as collection mechanisms. At superficial velocities over 50 cm s −1, sintered discs are capable of high efficiencies comparable with fibrous filters, but the pressure drop is typically 1.5–1.8 times greater. Both sintered discs and fibrous filters operate more efficiently wet than dry.