Measurement of the Nanoparticles Distribution in Flat and Pleated Filters During Clogging

Abstract

It is currently admitted that for each filtration process using pleated filters, at least three steps can be distinguished: depth and surface filtration, which are common to flat filters, and surface reduction. This step is caused by inefficient filling of the pleat due to the filter geometry. For combustion aerosol, it has been proved that this third step strongly depends on the filtration velocity resulting in an increase of the resistance when air flow decreases. This observation leads one to think that Brownian diffusion, higher for low velocities, could influence the clogging dynamic of a pleated filter.In this article, a protocol derived from the dust cake preparation method published by Schmidt is developed. The aim of this study is to measure the aerosol penetration inside a filter media as well as in a pleat using a scanning electronic microscope and energy dispersive X-ray spectroscopy elementary detection. This method has also been extended to the study of pleated filters to measure the particle distribution inside the pleat. Filters were loaded with nanoparticles in order to evaluate the specificity of the diffusional regime on the clogging of pleated HEPA filters. For pleated filters, two filtration velocities were investigated: 2.5 and 0.2 cm/s.

Association of fibrous filters for aerosol filtration in predominant Brownian diffusion conditions

“…For more details on the filter preparation and properties measurement, readers may refer to Bourrous and al. [14].…”

Simulations of filter media performances from microtomography-based computational domain. Experimental and analytical comparison

“…The thickness of the media was determined by Scanning Electron Microscopy (SEM) visualization. A fixation method followed by sanding and polishing steps were performed in the same way as that used by Bourrous et al [23] for the samples. 27 measurements performed on 6 images provide the averaged thickness value: Z exp ¼ 1185 AE 91 lm.…”

Electrospinning polyethylene terephthalate/SiO2 nanofiber composite needle felt for enhanced filtration performance

“…The formation of the filter cake was characterized by a rapid acceleration in pressure drop, due to a small pressure drop increase in the early stages of the filter life . The clogging point has been defined by many authors as the intersection of the tangent straight to the deep surface filtration (Figure ). Therefore, PET/SiO 2 NNF entered surface filtration earlier than PPS NF.…”