Patent ID: 6672753
Filing Date: 2004-01-06
Classification: B29B,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 longitudinal axis with a feed section, a barrier melting section and a metering section disposed sequentially downstream along said screw axis, a reorientation section is disposed between the barrier melting section and the metering section; said screw including a main helical flight having a push side and a trailing side, said main flight forming a feed channel at said inlet of said screw; a barrier flight disposed in said barrier melting section intermediate said main flight, said main flight having a constant pitch in the barrier melting section, said barrier flight and said main flight dividing said barrier melting section into a melt channel and a solids channel extending helically side by side, said barrier flight having helical threads with a diameter less than the diameter of helical threads of said main flight, so that melt material flows over said barrier flight and into said melt channel, whereby solid material conveyed along said barrier melting section is positioned adjacent said trailing side and whereas melt material conveyed along said barrier melting section is positioned adjacent said push side; said barrier flight discontinuing at a terminal end of said barrier melting section; said main helical flight passing into the reorientation section makes a rotation of at least 540Â° about said screw axis at a pitch less than the pitch of the main flight in the barrier melting section, said melt channel and said solids channel in said barrier melting section merging into a substantially uniform reorientation channel in said reorientation section thereby forcing solid plastic material conveyed along said reorientation section toward said push side of the main flight; and a secondary flight disposed in said metering section intermediate said main flight, and said main flight continuing into said metering section from the reorientation section, whereby solid material conveyed along said metering section is positioned primarily adjacent said push side of the main flight and whereas melt material conveyed along said metering section is positioned primarily adjacent said trailing side of the main flight.