Abstract This invention provides a method of and apparatus for the deep bed filtration of a liquid containing fine particles (generally on the order of less than 0.005 inches) to obtain an effluent of exceptional clarity. It has been discovered that filtration to this degree of clarity requires a compacted filter medium bed and that this bed compactness must be preserved during rejuevenation of the bed to avoid the dispersal of previously removed dirt particles throughout the filter medium. In this invention, the rejuevenation of the bed is carried out by the flow of liquid through the bed in the same direction as the direction of filtration, but at a flow rate at least twice the flow rate during filtration, while maintaining the configuration and compactness of the bed during both filtration and rejuevenation.
A method as defined in claim 1, wherein the filter media consists essentially of alumina of a size ranging from about 100 to about 300 mesh.
Claim 2
Dependent Claim
27 words
A method as defined in claim 1, wherein the filter media is an organic polymeric material of a size ranging from about 40 to about 80 mesh.
Claim 3
Dependent Claim
70 words
A method as defined in claim 1, wherein the body of filter media is confined in a tank with one end face of the body spaced from an end wall of the tank, and during the performance of both steps (1) and (2) fluid under pressure is injected into the space between the tank end wall and the body end face to maintain said body in a constant, compacted state.
Claim 4
Dependent Claim
29 words
A method as defined in claim 4, wherein the fluid under pressure is liquid during the performance of step (1) and a gas during the performance of step (2).
Claim 5
Dependent Claim
41 words
A method as defined in claim 1, wherein the inlet opening is connected to a source of cleaning fluid during the performance of step (2) and the outlet opening communicates with a wash waste receptacle during the performance of step (2).