MAAG’s CSC-R large scale screen changer with curved screens is designed for the use of one-way filter screens which do not require cleaning after the simple and safe screen change. The screen bearing pistons belong to MAAG’s modular filter system and its patented design use 75% of the piston surface as active filtration area. Also this filter execution can be installed for vertical or horizontal melt flow directly at the reactor discharge melt pump or pelletizer booster melt pump to avoid additional piping for reduction of melt residence time.