Method of throttle-valving control for the co-extrusion of plastic materials
AssigneeKortec, Inc.
InventorPaul Swenson
Life of this patent
Estimating the term…
Abstract
A multiple-plastic stream co-extruder, as for injection-molding cavities, in which the extruder is internally provided therewithin and therealong with a restrictor or throttle pin, rod or element that forces combined plastic material streams, formed with an interior core stream encased in outer and inner stream layers, into corresponding concentric annular flow stream layers that are ultimately split transversely in opposite directions into a cavity gated to the extruder, and with the core stream at a region of zero gradient in the transverse flow velocity profile within the extruder and cavity.
Claims13
A method of co-extruding multiple plastic material outer and interior flowing streams as for injecting through a gate region into a mold cavity to produce a molded product, that comprises, flowing the plastic materials from stream sources along a longitudinally extending hollow extruder;
- receiving the outer and interior streams from the extruder and combining the streams of such flowing plastic materials with at least one inner stream that is to serve as an interior core of a resulting molded plastic product within outer and interior streams of plastic material to serve as covering plastic material layers;
- restricting the combined streams within and along the longitudinally extending tubular extruder to force the combined streams to flow along concentric annular flow paths within and along the longitudinally extending extruder to the cavity gate region, with the annular core stream encased by interior and outer annular covering plastic material stream layers;
- and, at the gate region, splitting the concentric annular streams along opposite transverse directions to inject into corresponding opposite transverse sections of the cavity.
Dependencies are inferred from the claim text.