Abstract: A filter system for filtering cleaning solvents includes a first filter unit having mechanical filters such as paper or the like, through which the fluid is first pumped, and a second filter unit having adsorption chemicals, such as clays and charcoal, through which at least a portion of the fluid from the outlet of the first filter unit is passed and the outlet of the second filter unit is in communication with the inlet to the first filter unit for recirculating the fluid therefrom back through the first filter to filter and deposit carbon and clay particles from the second unit on the surface of the first filter unit thereby providing a multi-pass filter system.

Abstract: A consumer rebuildable filter cartridge for mounting in a fluid filter chamber in a fluid flow path includes inner and outer perforated tubular members mounted coaxially on a fixed end cap to form an annular chamber. A filter element of pleated sheet filter material is formed in a tubular construction and fitted into the annular space defined between the inner and outer tubular members and is sealed at each end by suitable resilient seal washers, compressed between the fixed end cap and a movable end cap. The inner and outer tubular members forms support structure for supporting the tubular paper filter element and permits the removal and replacement of such filter elements.