Patent ID: 8215477
Filing Date: 2012-07-10
Classification: B30B,B65G

Abstract:
1. An archimedes screw ( 1 ) for use rotating internally of a containing structure, the archimedes screw being located within the containing structure and comprising a shaft ( 2 ) and a helix ( 3 ), the helix ( 3 ) being coupled to the shaft ( 2 ), the shaft ( 2 ) comprising a central pin, wherein the archimedes screw ( 1 ) further comprises a plurality of sections which are threaded coaxially and solidly in rotation on the central pin, each of which plurality of sections exhibits different constructional and functional characteristics from others of the plurality of sections, wherein at least one of the sections ( 4 b ) located immediately upstream of a final section ( 4 a ) of the archimedes screw is made completely of metal, wherein at least some of the sections comprise a metal central sleeve ( 5 ) which couples with the shaft, which metal central sleeve ( 5 ) is sunk in a plastic material so that a portion of the helix ( 3 ) of the section is made of the plastic material in which the metal central sleeve ( 5 ) is sunk, wherein at least one of the first sections of the archimedes screw, located in proximity of a most upstream part of the archimedes screw, comprises a first portion of helix made of a softer plastic material than a plastic material with which a portion of helix of another section is made of, which first portion of helix is conformed such that, during a rotation of the screw, the first portion comes into contact with an internal wall of the containing structure.