Side inlet for plastics extruder includes a wide section for housing a grooved bush to provide channel for temperature control fluid

摘要

An extruder barrel (5) is made up of connected sections with a liner to accommodate channels for a temperature control fluid. Entries (2) for feed or additive material are provided in the side between the section joints (6, 7). The entry ports have a widened section, which houses a bush with annular grooves to provide a passage for the temperature control fluid. Several grooves can be used and the total cross-sectional area is preferably not reduced by more than 10% from the flow area available for the temperature control fluid in the rest of the extruder. The grooves can be turned or milled, and the bush fixed with interlocking teeth produced by spark erosion. The side feed can come from a pump or a side extruder, e.g. a twin screw extruder.