ABSTRACT
The pumping mechanism generally determines the flow characteristics and serves as a basis for division into the following categories: constant-pressure filtration, constant-rate filtration, and variable-pressure, variable-rate filtration. Filtration is the operation separating a dispersed phase of solid particles from a fluid by means of a porous filter medium, which permits the passage of the fluid but retains the particles. The importance of filtration techniques has been emphasized by the increased need for environmental protection. Basic laws governing the flow of liquids through uniform, incompressible beds serve as a basis in developing formulas for more complex, non-uniform, compressible filter cakes formed on the filter medium during cake filtration. In the development of filtration theory, the porosity plays a fundamental role in its relation to flow rates, pressure, and other parameters involved in the differential equations of flow through compressible filter cake. Constant-pressure filtration has long been the favorite method for obtaining experimental data in the laboratory because of its simplicity.
