Date of Award
Bachelor of Science
Paper Science and Engineering
It is of increasing importance to find improved methods of dewatering in the wet press section. New technology has allowed us to improve dewatering and final sheet properties with the press section. Presently, we are faced with a choice between two pressing configurations; the conventional roll press and the extended nip press. Both press configurations are discussed. The fundamental characteristics of paper which affect it's properties are density, fiber dimensions, fiber strength, fiber orientation, and fiber bonding. This thesis investigates the effect of the pressure pulse on the final sheet properties of bulk and strength of a kraft linerboard. Strength and bulk should both be optimized in the manufacture of linerboard. With the proper press configuration this may be accomplished. The KMW dynamic press simulator, it's operation, and it's use in this thesis is discussed. The procedure of the experiment is also outlined. The results of the experiment produced three significant conclusions: 1) Extended nip pressing gives higher dewatering rates than conventional nip pressing at comparable energy levels. 2) The longer nip dwell time and lower maximum pressure imparted by the extended nip press is more beneficial for higher bulk. 3) Conventional roll nip pressing imparts higher internal bond strength when crushing is not a factor. Also, this type of pressing gives higher bulk at specific strength levels in comparison to the extended nip pressings.
Johnson, Eric J., "The Comparison of Linear Nip Pressing vs. Extended Nip Pressing on the Bulk and Strength of Unbleached Kraft Linerboard" (1984). Paper Engineering Senior Theses. 204.