Patent ID: 8783939

Claim:
An extruder comprising: a housing having an inner wall, and at least two axially parallel shafts, the shafts being driven in a common direction and provided with at least two flight conveying elements, the at least two flight conveying elements intermeshing in a cross-section perpendicular to the shafts so as to strip each other at an axial distance (Ax) with a small clearance over an entire circumference, the at least two axially parallel shafts being in the housing at a distance (a) between a comb of at least one further flight and the inner wall of the housing, and wherein each conveying element has at least two conveying sections rotated through an angle, wherein each conveying section has an axial length (Ls) corresponding to at most ½ times an outer diameter (Da) of the conveying element; wherein the distance (a) is greater than a clearance distance (a′) of a flight stripping the inner wall of the housing; wherein the flight stripping the inner wall of the housing has a flight depth (b) that is greater than a flight depth (c) associated with the at least one further flight; and wherein one conveying section is offset relative to the next conveying section by an angle of no greater than 360° /number of flights.