LOADING FILTERS WITH MONODISPERSE AEROSOLS - MACROSCOPIC TREATMENT

A linear theory of the loading of particulate filters with monodispers e aerosols can be developed by analogy with that for deposition of ads orbed material within vapour filters. The theory predicts that the aer osol penetration decreases approximately exponentially with time, and that the deposit decreases with depth at a quantifiably more rapid rat e than exponential. The behaviour of the filter can be described in te rms of the layer efficiency and a further constant, the mass of deposi ted aerosol per unit volume of filter that results in a doubling of th e layer efficiency. Both parameters can be obtained from measurement o f the penetration of the aerosol as a function of time, and experiment s show that the same values give a reasonable fit to the observed spat ial deposition pattern. Discrepancies observed are probably due to the presence of higher-order terms than linear. Crown copyright (C) 1998 Published by Elsevier Science Ltd. All rights reserved.