High Vacuum Dewatering of Brown Paper Grades, 1995 Papermakers Conference Proceedings

John A. Neun, P.E. AES Engineered Systems The performance of high vacuum dewatering elements can be predicted by a model developed from pilot studies (previously published). The model uses machine speed, vacuum level, incoming sheet solids content, and flat box configuration to determine water removed from the sheet. Field data has been used to test the work, and it was found that dewatering depends to a large extent on furnish type and basis weight. Accordingly, further pilot tests were performed to expand the ranges of furnish and weight. To supplement the original data from virgin kraft, old corrugated container stock was used to make a range of light and medium weight sheets. Results show furnish and basis weight affect both the ultimate achievable dryness and the rate of water removal for a given vacuum. With this further resolution of dewatering knowledge, vacuum levels and box geometries can be used to optimize sheet dryness, wire drag, and vacuum use.