Changes in the performances of filter media during clogging and cleaning cycles

The performance of two filter media used in industrial air cleaning were st udied both in the initial state (new filter) and after a number of collecti on and pulse pressure cleaning cycles, The main difference between them is that one has anti-clogging properties and the other does not. The test aero sol is composed of alumina particles with a median volumetric diameter of 2 .6 mum (MMAD=4.8 mum) generated at a concentration of 700 mg m(-3). Filtrat ion took plate at a velocity of 2 cm s(-1). Two parameters, namely pressure drop and efficiency, were monitored according to the collection and cleani ng cycles, The comparison of the filtration efficiency of the two media and that of the corresponding industrial dust separator at the end of the cycl es showed a close agreement. The separation efficiency calculated with a ne w medium (corresponding to initial switch-on of the installation) was low a nd increased very quickly during the cycles. Finally, a phenomenological mo del was developed to represent the increase in pressure drop of a filter me dium after cleaning and was found to be in close agreement with the experim ental values, (C) 2001 British Occupational Hygiene Society. Published by E lsevier Science Ltd. All rights reserved.