The continuous screen changer is used to filter impurities out of the plastic production stream after the polymer has been melted.  Continuous screen changers are beneficial in the production stream as they allow the process to continue without interruption.  When the screen needs to be changed, either due to size change or cleaning, the production line does not need to stop.  Of the three types of continuous screen changers – continuous belt, rotary disc and dual bolt- dual bolt is the most prevalent.  The dual bolt allow the plastic to flow to one of two chambers. When the screen needs to be changed it diverts the flow of material to the other chamber.  Kreyenborg is a manufacturer of continuous screen changers found on the market today.