The role of porosity in filtration part 3: Variable‐pressure—variable‐rate filtration

Virtually all filtration literature has been concerned with constant rate or constant pressure with greater emphasis on the latter. In contrast to these types of operations, industrial filtrations involving centrifugal pumps are accomplished under variable‐pressure—variable‐rate conditions. In spite of its importance virtually no work has been reported in connection with variable‐rate—variable‐pressure filtration. Formulas developed for constant pressure and constant‐rate filtration are not in general applicable to operations effected by centrifugal pumps. Methods solving variable‐pressure—variable‐rate filtration problems are presented. A method of determining average filtration resistance as a function of compressive pressure under variable‐pressure—variable‐rate conditions is discussed, and formulas for determining point filtration resistance from data for average resistances are presented.