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United States Patent 4896969
Douris , ê et al. January 30, 1990

Method and apparatus for melting and conveying plasticated material

Dray January 30, 1990

Abstract

This invention relates to a method and apparatus for melting and conveying plasticated materials by independently developing an initial melt film which is necessary for proper conveying of the material. The apparatus includes a barrel having a cylindrical bore therethrough, a shaft rotatable in said bore which has a substantially circular cross-section, the shaft and bore defining a feed section, a metering section and a transition section between the feed and metering sections. The shaft is provided with a helical first channel means integral with the shaft for conveying said plasticated material in a downstream direction through the feed section, the transition section, and the metering section when the shaft is rotated. A helical second channel means for producing an initial melt film is provided integral with the shaft for subjecting the material in the second channel means to high initial shear rates to rapidly form a melted film of plasticated material in proximity to a point of commencement of the feed section. The second channel means terminates at a point of beginning of the transition section whereupon the first channel means has a step through the transition section which step disappears before a point of beginning of the metering section.