Mixer heads for polyolefin extruders.

摘要

An apparatus for the mixing of linear polyolefin materials having high viscosity in a single-screw extruder employing a mixing head (22) having a plurality of alternate longitudinal mixing channels (30) and wiping barriers (34), characterized by longitudinal radially-stepped regions on the opened bevelled leading edge portions of the outer surfaces of said wiping barriers (3A) to act as hydrodynamic wedges to the passage of polyolefin material passing between said surfaces and the inner walls of the extruder barrel; and both said radially-stepped, opened bevelled, leading edge portions of the outer surfaces of said wiping barriers (34) and the outer circumferential surfaces of full diameter of said mixer head (22), supporting an outer coating of gall-resistant material.