Screw type extruder with flow chambers externally and internally of screw

Abstract From the Canadian patent

A screw type polymeric material extruder with an elongated body having a cylindrical bore with a hollow screw in the bore the screw having external and internal threads. A cylindrical body is within the internal threads, and the screw with the wall of the bore and with the cylindrical body forms respectively, an, external material flow chamber and an internal material flow chamber. The cylindrical body can have channels for heating fluid and for additives or dyes. The screw can have openings for feeding one material to a single extrusion head with one mouth by way of both chambers, or the chambers can be supplied with the same or different materials which are fed by way of the chambers to …