METHOD OF ATTAINING UNIFORMITY IN PAPER WEBS ON A ROLL FORMER

摘要

A uniform paper web is made by directing a fiber stock jet onto a primary drainage area between convergent inner and outer belts, the inner wrapping a large part of a forming roll and at least the outer being porous and pressing an the inner. A narrow pulse-generating surface is located at an adjustable stationary point along the area, spaced adjacent to and across the width of the outer belt to momentarily interrupt free drainage and impose a pressure pulse on mobile fibers in syspension so that these become uniformly distributed before being locked in the web. The surface is pref. that of a bar and is curved in the belt travel direction.