Filtration system with helical filter cartridge

A filtration system for separating solid particles from liquid comprising a vessel having an inlet for unfiltered liquid and an outlet for filtered liquid, a partition within said vessel separating said inlet from said outlet, a filter cartridge supported at one end within an opening in said partition and adjacent the inlet, said cartridge comprising a cylindrical housing for supporting the cartridge in the opening in said partition, said housing having a partition having openings extending axially therethrough, a flexible ribbon in the form of a helix having a plurality of helical coils extending around the longitudinal axis of the helix, each of said coils having a plurality of radial grooves in at least one face of the ribbon, said grooves being of predetermined size corresponding to the smallest particle size to be trapped by the cartridge and prevented from entering the interior of the helix, a bottom plate for engaging the bottom end of said helix, said helical coils being sandwiched between the bottom of said housing and said bottom plate, a central rod extending along the longitudinal axis of said helix and having a top end attached to the housing partition and a bottom end extending through said bottom plate, a coil spring on the bottom end of said rod, and means on said bottom end of said rod for cooperation with said spring in applying a force to said helix in the axial direction to maintain the helical coils in closed position.