Patent ID: 6132075
Filing Date: 2000-10-17
Classification: B29C

Abstract:
A plasticating apparatus comprising:a barrel having an inlet and an outlet;a rotatable screw disposed within and cooperating with an inner wall of said barrel, said screw adapted for plasticating resinous material fed into said barrel through said inlet, said screw comprising:a feed section, a barrier section and a multi-channel wave metering section disposed sequentially downstream along said screw;said feed section including a main flight forming a feed channel at said inlet of said screw;a secondary flight originating in said barrier section branching from said main flight and disposed intermediate said main flight, said secondary flight and said main flight dividing said barrier section into a melt channel and a slush channel extending helically side by side, said secondary flight having helical threads with a diameter less than the diameter of helical threads of said main flight, whereby plastic material in said melt channel flows upstream over said secondary flight into said slush channel; andsaid secondary flight having a point of origin which provides a large initial clearance between said secondary flight and said inner wall of said barrel, said initial clearance adapted to allow solids to enter said slush channel from said solids channel, said initial clearance decreasing within one and one half turns about a longitudinal axis of said screw to a final barrier clearance, said final barrier clearance adapted to allow dispersed solid material to pass thereover.