Patent ID: 7635217

Claim:
An extruder assembly comprising: an elongated barrel having an inlet and a spaced, restricted orifice die outlet; a mid-barrel valve assembly located along the length of said barrel and including structure for selective restriction of material flow through the valve assembly; and at least one elongated, axially flighted screw assembly within said barrel and operable to move material from said inlet, through said barrel and valve assembly and out said die outlet, said screw assembly including a disrupting/homogenizing screw section upstream of said valve assembly operable to create a full choke of material, said disrupting/homogenizing screw section including a plurality of lighted screw parts presenting outermost flighting surfaces defining corresponding screw part diameters, with at least one of said screw parts having a right-hand pitch, and at least another of said screw parts having a left-hand pitch, each of said screw parts having a length less than a full pitch and less than the corresponding screw part diameter.