ABSTRACT
The literature of filtration is somewhat confused; the source of much of the confusion is the variety of ways investigators define and describe filtration efficiency. Chemical engineers refer to filtration as a separation process: particles are separated from a fluid or vice versa. Hence, the efficiency of a given separation process is called filtration efficiency. Many writers speak of the particle removal characteristics of a filter medium. Some, realizing that characteristics do not really say anything, speak simply of removal. Obviously, their eyes are on the fluid rather than on the solids. Other writers, perhaps with eyes on the solids, speak of fluid removal, or particle recovery. In gas filtration, writers refer to arrestance; the filter medium incarcerates the particles.
