FUNDAMENTALS OF PARTICLE SEPARATION AND AIR FILTERS

All techniques developed so far to separate particles from their liquid or gas dispersion systems are classified into three categories; (1) techniques which utilizes force field only, (2) those which use both force field and separation media (collection bodies), and (3) those which have separation media without any force field. The basic principles of these techniques are discussed in conjunction with the development of new types of particle separator. Fibrous air filters are classified into the second category. The optimal filter structure is discussed by studying the influence of fiber diameter, fiber orientation, binder content on a Filter Figure of Merit. Membrane filters are now widely used as an inline filter for pressurized gases. In order to develop prediction method of these membrane filters, the membrane filters are classified into five groups according to the internal structure, and the collection performance are evaluated in terms of the Filter Figure of Merit. Then, the prediction methods of collection efficiencies of membrane filters in each group are discussed.