FORCES ON FIBERS IN LOW-CONSISTENCY REFINING - SHEAR FORCE

An expression has been derived to predict the force acting on an ideal floc undergoing shear between passing bars of a refiner. This was acc omplished by considering the forces imposed by the corner and the surf ace of the bar separately. The validity of the resulting expression wa s tested experimentally on a single-bar refiner using model nylon floc s. The measured shear force was found to increase to a peak over the f irst 2-3 mm of the bar, and then decrease to an essentially constant l evel over the remaining width of the bar. The experimental results wer e in good agreement with predicted values from the theoretical express ion.