The Continuous Backflush Screen Changer performs much like the Continuous Screen Changer design. Polymer is divided into eight streams, all being filtered in the top and bottom piston. Unlike the CSC design, the backflush unit has two filtration cavities in each piston, allowing for twice the filtration of the comparable sized CSC design. The most unique aspect of the backflush CSC/BF is the capability of recycling or maximizing screen life while in the melt flow. When upstream pressure rises due to a high contaminant level, the PLC control automatically actuates each piston to its backflush position, allowing pressure to push contaminants off the dirty screenpack. Contaminants are purged out of ports in the bottom of the housing into a drip pan. Once the backflush sequence takes place, the recycled screens are returned to the home position until the sequence takes place again. The number of backflush sequences varies from process to process before a screen change is required; however increased screen life of 25 times or more is common.