ABSTRACT
The main functions of a press fabric are water removal from the sheet, sheet support and transportation, providing uniform pressure distribution, and imparting proper surface finish to the sheet. The fabric should provide proper protection for the sheet to resist crushing, shadow marking and groove marking. The basis weight of the sheet and its drainage characteristics are critical factors in determining the mechanism for water removal. Major symptoms of problems in flow-controlled nips are crushing and hydraulic flow mark. Water removal is aided by: soft roll covers, large diameter press rolls, double felting, and high sheet temperatures. An understanding of the fundamentals of transversal flow pressing is necessary to optimize press and press fabric design. The batt-on-mesh felt was developed and felt-making took another step forward to the benefit of the papermaking industry. The needling process can be engineered to affect the density, surface properties and permeability of the press fabric.
