Steven W Fleck: Rechargeable filter assembly. MCF Systems, Pettis & McDonald, May 14, 1991: US05015375 (30 worldwide citation)

A rechargeable filter assembly for removal of contaminants from liquids of all types, particularly dry cleaning solvents comprising three nested and spaced apart concentric perforated metal cylinders defining an inner cavity and an outer cavity held in spatial relationship by a base plate and remova ...