continuous rotary backflush and plastic rotary polymer CONTINUOUS ROTARY The vent and vacuum port will automatically purge air from the oncoming screen cavity to avoid air being passed into the melt flow. The pressure relief port will automatically purge material from the exiting screen cavity to ensure operator safety. The filter disc is enclosed between two body blocks and advanced in ultra-fine angular steps by the microprocessor control, allowing continuous rotary even at lowest speed, while maintaining a constant pressure drop.