Single nip presses and the benefits of innovative press fabric designs

摘要

Many new graphic paper machine installations have included a single nip press configuration as the press section. This technology affords a minimal structure of rolls, showers and vacuum boxes, however, offers challenges to press section water removal. The single nip press generally achieves press solids of approximately 50% at speeds of over 1200 mpm. Conventional press sections typically consist of two to four press fabrics in three or four press nips. Historically, deficiencies in one press fabric can many times be compensated for by increased performance in another press. The single nip configuration requires two press fabrics which go through a single nip. With the single nip press the Pickup and Bottom press fabrics are required to do all the dewatering. The goal of this paper is to review the performance requirements of single nip presses and discuss how the utilization of innovative press fabric materials has helped to improve machine output and expand the operational window of this type of machine configuration.