SHOE PRESSES AND SLEEVES FOR NEWSPRINT-CONCEPTS AND INITIAL OPERATING EXPERIENCE

摘要

Shoe presses offer a number of advantages to papermakers. The wide nip increases the press dwell time and allows higher lineforces (4500 - 5700 PLI) without increasing the maximum nip pressure. Therefore, press impulse, the quotient of line force and web speed, can be increased significantly. This is important for high basis weight sheets (linerboard) as well as high speed grades (newsprint). High speed newsprint machines with conventional presses have reduced press impulse to the point that it has become one of the prime limitations for producing high solid contents. The press impulse of a modern shoe press at a speed of 1700 m/min compared to a conventional 4-roll-press followed by a straight through press with 700 m/min is equivalent.