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US 4,249,877 AGranted
High-speed direct-drive extruder
OwnerJames F. Macheninventor
Life of this patent
Estimating the term…
Abstract
An extruder for thermoplastics having a directly motor-driven high-speed feed screw which mechanically force-feeds raw plastic pellets, pushing them forward under high pressure into a heat-transfer zone for melting, and finally through a static mixer, to deliver a pressurized homogeneous melt to an extrusion die. Melt pressurization results entirely from the mechanical force-feeding action of the screw rather than through the viscous shear action found in conventional screw extruders.
Claims10
A plastic extruder of the type described comprising:
- a cool bore;
- a raw material inlet for said bore;
- a non-plasticating feed screw in said cool bore;
- said screw rotatable in said cool bore such that the maximum screw RPM times the square root of the screw diameter in inches equals at least 500;
- the length to diameter ratio of said screw being less than 16 to 1;
- said cool bore communicating with a heated-wall melting chamber;
- means in said melting chamber for conducting heat from said heated walls into a variety of portions of the material flow stream through said melting chamber;
- mixing means also in said melting chamber downstream from said heat conducting means;
- and, an extrudate outlet for said melting chamber.
6 more elements
Dependencies are inferred from the claim text.