Extruders for processing polymer materials

Abstract

The invention relates to an extruder (1) for processing polymeric materials with at least two screws (3a, 3b, ...) rotatable in a common housing (2), with a feed area (A) for introducing the material to be processed into the extruder (1), and a further downstream extrusion area (C) for melting the material, wherein the housing (2) has at least one feed opening (4) formed in its outer wall in the feed area (A) for introducing the material to be processed into the gripping area of ​​the screws (3a, 3b, ...), wherein in the extrusion area (C) there is a largely constant narrow screw gap (7) between the outer diameters of the screws (3a, 3b, ...) and the inner wall (8) of the housing (2), wherein the housing (2) in the feed area (A) and the extrusion area (C) is a narrow screw gap (7) that is essentially constant up to the screw exit.in an area around the feed opening (4) a pocket (5) extending over a partial longitudinal section of the extruder (1) along the screws (3a, 3b, ...) has, wherein the pocket (5) has in its entire longitudinal course an enlarged screw gap (7') between the outer diameters of the screws (3a, 3b, ...) and the inner wall (8) of the housing (2), compared to the screw gap (7) in the extrusion area (C), wherein the feed opening (4) is formed laterally on the extruder (1) and opens only into the capture area of ​​one of the screws (3a, 3b, ...), wherein it is provided that the central longitudinal axis of the feed opening (4) intersects the central longitudinal axes (3a', 3b', ...) of the screws (3a, 3b, ...).