Abstract: A treatment element to treat material in a multi-shaft worm machine has an outer contour with at least one outer contour portion, the associated evolute of which is a quantity of at least three points, each of the points lying outside the longitudinal axis and within the outer radius of the treatment element and two respective adjacent points having a spacing from one another, which is less than half the core radius. The treatment element ensures high flexibility during the adjustment of shear and/or extensional flows on the material to be treated.

Abstract: A treatment element to treat material in a multi-shaft worm machine has an outer contour with at least one outer contour portion, the associated evolute of which is a quantity of at least three points, each of the points lying outside the longitudinal axis and within the outer radius of the treatment element and two respective adjacent points having a spacing from one another, which is less than half the core radius. The treatment element ensures high flexibility during the adjustment of shear and/or extensional flows on the material to be treated.

Abstract: A treatment element to treat material in a multi-shaft worm machine has an outer contour with at least one outer contour portion, the associated evolute of which is a quantity of at least three points, each of the points lying outside the longitudinal axis and within the outer radius of the treatment element and two respective adjacent points having a spacing from one another, which is less than half the core radius. The treatment element ensures high flexibility during the adjustment of shear and/or extensional flows on the material to be treated.

Abstract: In a method of melting and homogenizing multimodal and bimodal polyolefins, use is made of a multiple-shaft first extruder (1) and a second extruder (2) which is disposed downstream thereof in the conveying direction (17). The second extruder (2) is also of multiple-shaft design. The outside diameter of the screw shafts (14, 15) of the first extruder (1) is smaller than the outside diameter of the second screw shafts (29, 30) of the second extruder (2). The first extruder (1) is driven at a higher rotational speed than the second extruder (2). The shear rate in the first extruder (1) is higher than in the second extruder (2).

Abstract: A twin screw extruder has a casing with a working direction, two partially intersecting casing bores, which are parallel to each other, two shafts, which are disposed in the casing bores and which are drivable to rotate in the same direction of rotation about an axis of rotation, the axes of rotation having a distance A from each other, and single-flight kneading disks, which are fixed on the shafts and have surface lines extending parallel to the respective axis of rotation. The kneading disks, in a cross-section perpendicular to the axis of rotation, have a crest, which is formed as a segment of a circle about the respective axis of rotation and which has a crest angle b and a radius RA, a bottom, which is formed as a segment of a circle about the respective axis of rotation and has a bottom angle g and a radius RI and two flanks, which join the crest and the bottom, RA>RI, A≈RA+RI and 0°≦b≦45° applying.

Abstract: A multi-shaft screw-type extruder having a casing with two parallel intersecting casing bores and two shafts drivably disposed in the casing bores. Screw elements intermeshing kneading disks are fixed on the shafts The widths of the respective crest portions of the kneading disks are smaller than the disk width and form mixing-and-scraping-studs on the periphery of the disks. The mixing-and-scraping-studs on each kneading disk are axially misaligned relative to each other such that their peripheral faying surfaces jointly cover the entire disk width.

Abstract: In a method of carrying out continuous preparation processes on tightly meshing extruders rotating in the same sense such as twin-screw and multi-shaft screw-type extruders, the extruder is operated at a screw speed of rotation of at least 800 rpm, accompanied with a simultaneous increase of the so-called "torque density" (M.sub.d /a.sup.3) of at least 11 Nm/cm.sup.3 and a volumetric ratio (Da/Di) of at least 1.5.