Screw extrusion and mixing appts. - having cooperating grooved barrel and screw, for extrusion of thermoplastic or thermosetting materials

摘要

Extrusion and mixing appts. comprises a barrel with inlet and outlet ends and a rotating screw reciprocably located within the barrel. The internal surface of the barrel is grooved as is the surface of the screw. In a first section nearest the inlet end of the barrel the depth of the grooves in the barrel gradually increases whilst that of the grooves in the screw gradually decreases. In this way an increasing proportion of the working material is forced into the barrel grooves. In a second section the barrel grooves are abruptly decreased and that of the screw increased to cause the material to abruptly flow from the barrel to the screw grooves. The length of the second section is considerably shorter than the first. Homogeneous blending is obtd.