Restricting and mixing element for twin-screw extruders

摘要

The invention relates to a restricting and mixing element for twin-screw extruders for compounding plastics. The aim of the invention is to improve the quality of the extrudate. The object of the invention is to provide a restricting and mixing element which, in variable arrangement on the shank shafts between active conveying zones, makes it possible to adapt the mixing and homogenising process optimally to the processing tasks. The solution according to the invention provides for the frustoconical restricting and mixing elements to be arranged at different cone angles in a combination of element pairs with the same cone angle between active conveying zones of screw bushings, it being possible to set the size of the gap present between the circumferential surfaces of the elements in the engaging region of the shank shafts by means of exchangeable shims arranged on the shank shafts.