Twin Screw Side Degassing

image Coperion (Stuttgart, Germany) has made a number of improvements to its ZS-EG side degassing units: The screw set has been optimised, the standard models of the ZS-EG are designed for an absolute vacuum of up to 50 mbar, lower degassing pressure upon request. Moreover the ZS-EG standard units are equipped with a variable speed screw drive.

Compared to an open vent dome the twin screw side degassing unit offers many advantages. It can be fitted at low cost to a combi barrel segment of the ZSK twin screw extruder. By replacing an atmospheric venting barrel with a combi barrel it can be retro-fitted in order to make full use of the performance of ZSK technology,delivers effective degassing, even with high air or moisture content of the bulk material, at acceptable residence times so that plant throughput can be raised by 10 to 15 %, improves compound quality and consistency since no material can fall back into the processing unit from the vent, lowers production costs through reduced cleaning and maintenance times as well as through lower wear, simplifies machine control through simple operation and reduces accident risks, particularly during start-up.
The ZS-EG has deep cut co-rotating twin screws that deliver its high venting capacity. Due to the direction of rotation they keep the product within the processing zone. The large free cross-section of the flow channel ensures low gas velocities. With quick release connections the ZS-EG is very user friendly and can be dismantled easily for cleaning and maintenance.
Typical applications for twin screw degassing units include for example the manufacture of glass reinforced or highly filled compounds, wood plastic compounds (WPC) or thermoplastic elastomers (TPE).