scope:

This Technical Information Paper provides guidelines for design of a conventional paper machine headbox approach piping between the machine chest discharge and the headbox. This document recognizes that there are also multiple compact wet end system designs being marketed by several paper machine suppliers. These systems are unique to each supplier and are outside the scope of this document to define. 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 residual (or random) 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. As with many things in engineering, there can be more than one satisfactory way to engineer solutions. This document represents, in some cases, consolidation of multiple methods or design specifications.