The Performance of Needle Punched Felt Filters

Abstract

The present paper deals with the filtration performance of needle felt filters prepared from various kinds of materials. Single fiber collection efficiency was correlated experimentally with Reynolds number and the direct interception parameter, taking into account both volume fraction and needle punching density. Although the difference in the collection efficiency stemming from electrostatic charges on the fiber surface was observed, its dependence on the interception parameter showed the same tendency for all the materials.
It was verified that the drag coefficient of felt filters varied inversely with Reynolds number and depended strongly on the volume fraction. Also an empirical expression of the drag coefficient applicable was obtained in a wide range of the volume fraction.