Patent ID: 7374676

Claim:
High rate depth filtration apparatus for removing suspended solids from liquids, said apparatus comprising: a) a filter housing having an axial flow direction therethrough for liquid; b) a first perforated panel fixedly secured in said housing transverse to said flow direction; c) a second perforated panel movably secured in said housing transverse to said flow direction and spaced from said first perforated panel; d) an influent liquid conduit located adjacent said fixed first panel, said influent conduit connected to a source of liquid having suspended solids therein; e) an effluent liquid conduit located adjacent said movable second panel thereby establishing said axial flow direction through said housing from said influent conduit to said effluent conduit; f) substantially spherical and compressible filtration media of individual, fibrous lumps of bundled, crimped fibers located between said first and second panels; and g) a piston for moving said second perforated panel toward and away from said fixed first panel to define: i) a fixed filter bed of said media compressed between said panels during filtration, said filter bed having a porosity gradient across the bed proceeding progressively from more porous to less porous in said axial flow direction; and ii) a cleaning chamber between said panels during washing wherein said second panel is moved away from said first panel to provide said media in an uncompressed condition for washing in said axial flow direction.