Improvement of thermal and mechanical dewatering of paper in a hot press nip simulator

A laboratory-scale apparatus has been developed to investigate the thermal and mechanical dewatering of paper in the press nip of a high speed paper machine. The apparatus is basically a hammer-and-anvil-type dynamic press simulator modified to also simulate hot nip conditions. Using this device, dewatering experiments have performed on household paper tissue over a wide range of press conditions. The influence of different underlays, maximum pressure and temperature on mechanical dewatering by compression, capillary transfer between porous compressible materials, thermal drying and rewetting of the sheet are discussed.