Takashi Bando

Drainage Mechanism on a Twin-Wire Former(Part 3) Dependence of the structural anisotropy of paper sheet on the pulsating drainage.

The structural anisotropy throughout the thickness of a paper sheet made on the blade-type Twin-Wire Former was analyzed for study of the effects of the pulsating drainage on the variation of the orientation ratio of fibers in the sheet.In contrast with the orientation ratio of fibers in both top and bottom surface layers, the orientation ratio of the middle layer was significantly affected by the change of the J/W ratio, the number of blades, and vertical or horizontal alignments of the blades in the forming zone.The orientation ratio of the middle layer of the sheet made on the Twin-Wire Former was interpreted in terms of the cumulative shear factor acting to the pulp slurry in the forming zone estimated from the theoretical analysis of the drainage model of the blade-type Twin-Wire forming.