Extrusion machine

a machine for processing thermoplastic material comprising a casing including two generally opposing surfaces which at least in part define an enclosed working chamber, means for heating and controlling the temperature of the two surfaces of the working chamber, a gravity fed hopper for introducing said material through an inlet into the working chamber and an outlet for leading processed material away from the working chamber, a rotor mounted for rotation within the casing and having a root and a plurality of blades extending outward form said root and disposed between the said surfaces of the working chamber with adjacent blades separated by an open space defined by thrust faces of adjacent blades and portions of the two surfaces of the working chamber, each blade extending from the region of the inlet to the region of the outlet and each blade including generally oppositely directed first and second surfaces with the first blade surface closely confronting one of said surfaces of the working chamber to form a first region of shear and with the second blade surface closely confronting the other said surface of the working chamber to form a second region of shear, the blades being so shaped to transport material from the inlet to the outlet by the angle of the blades and the forces arising from the difference between the surface area of the thrust faces of the blades and the relatively larger area of the generally opposed surfaces of the working chamber and serving, in use, to produce multiple shearing action and mixing action and improved heat transfer in the material contained in the spaces during transport action and processing thereof from the inlet to the outlet.