Introduction to Double Column Backflush Screen Changer The hydraulic screen changer can be installed on any new or existing extruder, melt pump, reactor, or other extrusion production line. It can be used to filter any type of polymer, rubber, or ceramic melt. The dual column backwash screen changer is a type of screen changer. The active backwash screen changer is generally composed of the screen changer body, plunger, metal filter screen, porous plate, filter support, backwash body, backwash p