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The collection and cleaning cycles of the filter media used in industrial air cleaning were analysed experimentally. Examination of the simultaneous pressure drop and filtration efficiency changes established that the efficiency of filters increases sharply during the collection phase only to fall back during cleaning. The amplitude of this reduction of efficiency is attained as the cycles progress. In contrast, the residual pressure drop rises. Our study has shown that treating the surface with thermobonding or covering the surface with a fine layer of submicronic fibres promotes detachment of the dust cake and prevents particle penetration inside the initial porous media. [Copyright &y& Elsevier]

The filter media used in industrial air cleaning, if they are regenerable, are subjected to clogging and cleaning cycles. Their performance is closely linked to these two operating phases. A model of the phenomena based on the assumption of patchy cleaning is presented. The aim of the study was to determine the pattern of a parameter representative of cleaning, namely the cleaned fraction, from experimental values of the residual pressure drop of a filter medium subjected to given filtration conditions. This characterisation then allows the pressure drop pattern of the filter medium over a number of cycles to be determined. A comparison was made with the experimental results obtained on a laboratory test rig. Close agreement was observed, which confirms the hypothesis of patchy cleaning in this approach to describe the filtration and cleaning phenomena of a filter medium. [Copyright &y& Elsevier]

The performance of two filter media used in industrial air cleaning were studied both in the initial state (new filter) and after a number of collection and pulse pressure cleaning cycles. The main difference between them is that one has anti-clogging properties and the other does not. The test aerosol is composed of alumina particles with a median volumetric diameter of 2.6 mm (MMAD=4.8 μm) generated at a concentration of 700 mg m-3. Filtration took place at a velocity of 2 cm s-1. Two parameters, namely pressure drop and efficiency, were monitored according to the collection and cleaning cycles. The comparison of the filtration efficiency of the two media and that of the corresponding industrial dust separator at the end of the cycles showed a close agreement. The separation efficiency calculated with a new medium (corresponding to initial switch-on of the installation) was low and increased very quickly during the cycles. Finally, a phenomenological model was developed to represent the increase in pressure drop of a filter medium after cleaning and was found to be in close agreement with the experimental values. [ABSTRACT FROM AUTHOR]