Rheological design of screen changers

Rheological design of Screen Changers

To define the size of a screen changer we need to know the extruder output, polymer and grade, shear rate, expected contamination level and target pressure lost.

This data is fed into our latest computer modelling programme to indicate both the size of the screen changer but also the optimum flow channel dimensions.

It clearly shows that the biggest part of the calculated pressure loss is produced by the filter element in front of the breaker plate. The inlet geometry of the screen changer interface to downstream components has to be designed to minimise shear the melt.

For this, KREYENBORG offers adaptors taking into account the flow behaviour of the polymer to avoid high shear rates at the inlet into the screen changer.