New Concept for 100% Measurement of Paper Basis Weight, 1998 Process & Product Quality Conference Proceedings

A high priority for the United States pulp and paper industry is to improve product quality and lower manufacturing costs. To this end, the industry has embarked on a technology program to upgrade current on-line inspection ethods for web products. With financial support from the US Department of Energy (USDOE) Agenda 2020 – Industries of the Future Program, the American Forest and Paper Association has initiated a project for demonstration of new paper basis weight measurement concepts compatible with the goal of 100% inspection. Current single-point scanning basis weight gauges utilized on paper machines periodically traverse the web in the cross direction resulting in a very sparse sampling of the total web area. A new concept under investigation at the USDOE’s Pacific Northwest National Laboratory (PNNL) seeks to replace the scanning sensor head with a distributed array of point sensors capable of sampling all points in the cross direction simultaneously. This new method replaces the traditional point beta source and ionization chamber with a distributed line source accompanied by discrete, stationary scintillation detectors. This paper summarizes the new measurement concept and reviews the status of the multi-year technical effort.