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Involute Screw Elements

New ZSK extruder screw elements for higher throughputs

To significantly increase throughput rates of our first-class ZSK extruder series, we have developed special involute screw elements with a new and patented* cross section design.

These screw elements are ideal for highly-filled recipes (70-85% CaCO3, TiO2, mainly based on PP/PE and 20-50% talc for automotive grades) for which the dispersion rating and the incorporation of the filler represents a limitation. Besides higher throughput rates, these involute screw elements ensure higher loading of filler, better dispersion and homogenization, lower energy consumption (SEI in kWh/kg) and a significant increase in profitability.

Comprehensive tests at our test lab in Stuttgart, Germany, showed a remarkable throughput increase depending on the recipe. For example, when processing PP and 70% CaCO3 on a twin screw extruder ZSK 58 Mc18 the new screw elements achieved a significant throughput increase from 550 kg/h to 900 kg/h. Similar results have been reached when processing PE with 80% CaCO3 on a ZSK 92 Mc18. In this case thoughput was increased from 2.200 kg/h to 3.000 kg/h.

*Patent: EP 2 483 051 B1