New Wet End Weight Measurement System Opens Papermaking Optimization Opportunities, 1998 Process Control, Electrical & Info. Conference Proceedings

Machine direction (MD) and cross direction (CD) control of basis weight has usually relied on measurements located at the dry end of the paper machine. As a result of this transport lag, efficiency of control is degraded. For multi-ply machines, it has not been possible to control the MD or CD weight of the individual plies. This paper reports on a new under-wire sensor that provides fast, continuous, full-width measurement of MD and CD weight at the wet end of the paper machine. This sensor system also provides monitoring of drainage rate and stock conductivity. It can be installed on multi-ply multi-former machines to monitor and control weight of individual plies. Integrated into a Distributed Control System, the new sensor technology can be effectively used in optimization of the papermaking process and final products. Use and interaction of wet end chemicals and other functional additives can be monitored, analyzed and proper action taken as necessary. The almost instantaneous measurement capability of the new sensor is a valuable addition to Total Machine Monitoring System technology. High frequency monitoring of machinery condition can be combined with process and product quality measurements for “cause and effect” analysis. It is predicted that the coming decade will see major strides in papermaking optimization via wet end measurements.