Fine mist filtration by wet filters—I. Liquid saturation and flow resistance of fibrous filters

Experimental and modelled efficiencies during the filtration of a liquid aerosol with a fibrous medium

“…However, contrary to the initial efficiency of a dry filter for which there are many models in the literature, few authors have modelled the efficiency of a wet filter. Almost all the models described in the literature are global; they consider that the accumulated liquid is evenly distributed inside the filter (Conder and Liew, 1989;Gougeon, 1994;Gougeon et al, 1996;Liew and Conder, 1985;Payet et al, 1992). This is not necessarily the case because the amount of liquid trapped in the filter decreases as one approach the bottom of the filter.…”

Clogging of fibre filters by submicron droplets. Phenomena and influence of operating conditions

“…This was explained by Davies (1973) as possibly being due to droplets of liquid aerosols with a wetting capacity approaching and dampening the ÿbres by capillary action, increasing their diameter and thus reducing both the ow resistance of the ÿlter and its e ciency. Liew and Conder (1985) contributed a number of additional details and showed that the reduction in e ciency is only true in di usional regime and in the case of low packing density ÿlters and large ÿbre diameter. In other cases, the e ciency increases during clogging due to the e ect of an increase in the inertia and interception mechanisms.…”

Measurement of oil entrainment rates and drop size spectra from coalescence filter media

“…Unfortunately large drop entrainment is a rare event that occurs at the rate of perhaps one drop per minute originating from anywhere on a large area of filter surface. This has to do with the way oil drains intermittently across the downstream face of a filter (Liew and Conder, 1985;Kampa et al, 2014) and requires the ability to monitor a large region of the filter surface. A third difficulty, affecting especially the detection of large drops, arises from the fact that the operating behavior-and therefore presumably also the entrainment behavior-of coalescence filters changes gradually over very long periods of time (Conder and Liew, 1989;Contal et al, 2004;Charvet et al, 2010;Kampa et al, 2015).…”