Drainage During Roll Forming - Model Validation Using Pilot Papermachine Data, 2000 Engineering Conference Proceedings

Vaughn J. Wildfong, Jay A. Shands, Douglas W. Bousfield, Joseph M. Genco--The geometry and corresponding drainage over a forming roll on a papermachine twin wire gap former is examined. A twin wire gap former consists of a constant pressure-forming element, in this case a roll, followed by a variable pressure bladed section. In the current work, an analytical solution is presented to a phenomenological model describing the constant pressure forming process. The model output consists of filtrate volume drained over the roll. To test the validity of the model, a series of pilot papermachine trials were performed with furnishes typical of newsprint and free-sheet fine paper. Headbox samples were taken and tested in a drainage device to determine the drainage resistance coefficients required in the model. The drainage occurring over the former was the criteria used for determining model accuracy. The output from the drainage model matches the volumetric flow rate measured on the pilot machine data within 15%.