a twin-shaft press used in treating the surfaces of paper and cardboard (sizing, coloring, finishing with polymers or mineral substances).
The sizing press is used in the production of writing paper, paper used for printing and various industrial purposes, and paper used for paper bags and packaging. The press is generally installed in the drying section of the paper machine. Sizing presses are classified, according to shaft arrangement, as vertical, horizontal, or inclined. Usually one of the shafts is covered with a hard rubber and the other with soft rubber. The pressure between shafts is 1–3 meganewtons per sq m (10–30 kilograms-force per sq cm). The shafts are pressed together by a hydraulic or pneumatic mechanism.