scope:

This Technical Information Paper provides guidelines for design of paper machine headbox approach piping between the machine chest discharge and the headbox. The approach system has a significant influence on uniformity of the final sheet of paper. The goal of this TIP was to compile information on current approach piping guidelines from machine builders, other equipment suppliers, design engineers, and paper company representatives. The purpose is to provide design guidelines that paper companies can use to minimize machine direction, cross direction, and diagonal and basis weight variation on paper machines. The guidelines were developed for paper machines operating conventional headboxes. Changes may be required for application on machines operating at low (<0.2%) or high (>2.0%) headbox consistency.