Development of Test Method for Evaluating Filtration Performance of A Filter Element

Filtration process has wide range of applications in the industry, commerce and domestic
life. It has been rightly said that the heart of any filter is the filter medium. Hence, it is
important that filter medium has the combination ofproperties to ensure the effectiveness
of filtration process. Two crucial methods to predict efficiency of a filter medium are by
addressing its porosity (the ratio of void volume to bulk volume) and permeability (the
ease ofotherwise with which thatfluidflows through the medium).
Currently, filters produced by a local company are sent to overseas for performance
testing. However, due to cost and equipments availability, it is proposed to develop the
test procedure locally. The project's objectives are mainly to study the characteristics and
develop physical and quantitative test methods for the porosity and permeability
measurements of fibrous filter media rated 10, 28 and 50 micron supplied by the local
company.
Two methods are applied to evaluate the samples in this project. First method is by
imaging using Scanning Electron Microscope (SEM). From the images, observation is
done to evaluate the samples' structures and porosity calculations are done using
ArcView GIS 3.2 Software. The second part is by performing gas flow test to calculate
permeability, average permeability coefficient, flow average pore diameter, fiber
diameter, specific pore diameter and viscous-term coefficient. Then, these values are
compared with the filter media sizes.
From the study, it can be concluded that
• Fibrous filter media internals are consists of large number of fiber layers, each
sparsely populated and distributed throughout the length, width and thickness.
• Porosity values are independent of the filter sizes for fibrous filter media as the
pores in fibrous filter media are randomly oriented.
• Permeability values increase as filter media sizes increases which show that the
ease for fluid flow increases as the sizes of open pores increases.