Stirling Cycle Engine Analysis

Extruder, especially a vertically arranged extruder, and a system useful for recovery of scrap plastic film. An extruder feeder section comprising an initial portion of the extruder barrel has rotation retarding formation, preferably axially extending grooves, and forced feed fluid cooling. A vented section between first and second conveying sections of the extruder barrel has a relieved area including a guiding surface to cause plastic to gradually reconverge to the confines of the main barrel surface. A screw shank extending beyond the extruder outlet has a multi-piece seal which is anchored from rotation with the shaft.