Design equation for paper machine press sections

Water removal in the press section of paper board, and pulp machines has an important influence on machine efficiency and cost. A press section design equation, based on the decreasing permeability model of wet pressing, is d escribed. It is used to predict the effects of changes in operation, equipm ent and furnish on water removal in a press nip. The equation accounts for operating parameters such as nip load, machine speed, basis weight and web temperature. The two furnish-dependent coefficients can be determined by pr essing handsheets. Several examples from studies on commercial and pilot ma chines are used to illustrate the method and demonstrate its accuracy.