The invention relates to a four-flight screw element for a multishaft screw machine with screw shafts rotating in the same direction and at the same speed. The two screw elements according to the invention, which are located opposite each other directly adjacent on two directly adjacent screw shafts, practically clean each other in pairs. The invention also relates to the use of the screw element according to the invention in a multishaft screw machine and to a multishaft screw machine which is equipped with a pair of screw elements according to the invention, as well as to a method for the extrusion of plastic or viscoelastic masses using the screw element according to the invention.

An extruder system for processing washed polymer particles, at least comprising an MRS extruder, which has: a housing having an inner housing cavity, the housing cavity extending at least between an inlet opening and an outlet opening and comprising at least one degassing zone; and an extruder screw, which can be rotated in the housing cavity and which has at least one helical extruder screw flight. The extruder screw is divided into: an inlet screw section, into which the inlet opening leads; a multi-screw section, in which a plurality of satellite screws rotate together with a main screw and additionally rotate about their own axis, the diameter of the multi-screw section being larger than the screw diameter of the inlet screw; a transition cone, which is formed between the inlet screw section and the multi-screw section; and an outlet screw section, which has a smaller diameter than the multi-screw section.

An extruder system for processing washed polymer particles, at least comprising an MRS extruder, which has: a housing having an inner housing cavity, the housing cavity extending at least between an inlet opening and an outlet opening and comprising at least one degassing zone; and an extruder screw, which can be rotated in the housing cavity and which has at least one helical extruder screw flight. The extruder screw is divided into: an inlet screw section, into which the inlet opening leads; a multi-screw section, in which a plurality of satellite screws rotate together with a main screw and additionally rotate about their own axis, the diameter of the multi-screw section being larger than the screw diameter of the inlet screw; a transition cone, which is formed between the inlet screw section and the multi-screw section; and an outlet screw section, which has a smaller diameter than the multi-screw section.