Patent ID: 6942376

Claim:
An extruder for producing a thermoplastic material having a first and second portion, namely: (a) an axially extending barrel; (b) first and second screw conveyers co-axially disposed within said barrel, said second screw conveyer co-axially disposed within said first screw conveyer with relative rotatable movement between said first and second screw conveyers so as to define a first passage for conveying thermoplastic material from an input to a melt zone and then an output and define a second passage from said melt zone to said output; (c) a connecting passage for communication between said first and second passages whereby a first portion of said thermoplastic melt is conveyed through said first passage to said output and another portion of said thermoplastic melt is conveyed through said connecting passage to said second passage; (d) said second screw conveyor including an aperture for communication of said another portion of said thermo plastic melt from said second passage to said output; (e) means for merging said first and second portions together.