Plasticating screw for an extruder or extrusion press, having a narrower land width in the transition region
AssigneeLindauer Dornier Gesellschaft mbH
InventorFriedrich Mueller
Life of this patent
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Abstract
A plasticating screw for an extruder or an extrusion press has a thread change, whereby the volume of the transporting cross-section does not change and thus a pressure increase in the region of the thread is avoided. To this end, in the region wherein a first and a second screw thread of the plasticating screw overlap, the thread width outside the overlapping region is equal to d and the thread width inside the overlapping region is equal to ½ d.
Claims7
A plasticating screw for an extruder or extrusion press having a high polymer melt through-put, wherein the plasticating screw comprises a screw shaft received and rotatably driven in a cylindrical barrel in order to transport the admitted plasticatable polymer to an extruder nozzle located at the other end, the polymer undergoing plastication and being transported and mixed by a screw channel formed by a first flight running helically along the screw shaft, and wherein in at least one region of the longitudinal extent of the plasticating screw at least a second flight running helically along the screw shaft overlaps the first flight, characterized in that the cross-sections of the at least two flights (4, 5) in the overlapping region are reduced to such an extent that their overall cross-section corresponds to the cross-section of the first flight (4) immediately before the overlapping region (7).
Dependencies are inferred from the claim text.