Apparatus for Extruding and Cutting Thermoplastic Material into Pellets (Patent No: 554124)

Inventor: Halverson, Ernest N. (assignor)

Location: Edmonton

Comments: N/A

Description: Issued March 11, 1958

Ernest N. Halverson, Edmonton, Alberta, Canada, assignor to Canadian Industries Limited, Montreal, Quebec, Canada. Application August 4, 1956, Serial No. 712,434.
12 Claims.

1. An apparatus for forming pellets of thermoplastic material, said apparatus comprising an inverted hollow, substantially frustoconical die, said die being perforated by a plurality of extrusion orifices regularly spaced around its periphery; at least one cutter knife located within said die adjacent to the internal face thereof and adapted to rotate in a plane parallel to that of said internal die face in the locus of said extrusion orifices; means for supporting and rotating said cutter knife; means adapted to forward molten thermoplastic material to said extrusion orifices under sufficient pressure to extrude said molten thermoplastic material therethrough; means for maintaining and controlling the temperature of said thermoplastic material prior to extrusion; and means for forwarding a fluid to, and conducting said fluid through, the open internal core of said die in order at least partially to solidify said extruded thermoplastic material and to convey said extruded and cut thermoplastic material away from said die immediately after it has been cut.

2. An apparatus for forming pellets of thermoplastic material, said apparatus comprising a die, said die comprising an internal diepiece and an external diepiece both being hollow and substantially invertedly frustoconical in form and adapted to form, together with a layer of insulating material intermediate said diepieces, an integral unit, and said die being perforated by a plurality of extrusion orifices regularly spaced around its periphery; at least one cutter knife located within said die adjacent to the internal face thereof and adapted to rotate in a plane parallel to that of said internal .die face in the locus of said extrusion orifices; means for supporting and rotating said cutter knife; means adapted to forward molten thermoplastic material to said extrusion orifices under sufficient pressure to extrude said molten thermoplastic material therethrough; means for maintaining and controlling the temperature of said thermoplastic material prior to extrusion; and means for forwarding a fluid to, and conducting said fluid through, the open internal core of said die in order at least partially to solidify said extruded thermoplastic material and to convey said extruded and cut thermoplastic material away from said die immediately after it has been cut.

5. An apparatus according to claim 1 wherein said extrusion orifices are constricted immediately adjacent the internal die face such that they act as thin-walled orifices.

9. An apparatus according to claim 1 or 2 wherein said extrusion orifices contain bushings.