Measurement of Normal and Shear Forces during Refining Using a Piezoelectric Force Sensor

摘要

The normal and shear forces acting on pulp floes and wood chips have been measured over a 5 mm section of an individual bar in the stationary plate of a laboratory single-disc refiner, using a novel piezoelectric force sensor. The results of this preliminary study indicate that the forces on pulp floes at 20% consistency are qualitatively similar to those at low consistency, measured in a previous study. There is a large peak in both the normal and shear forces occurring over the initial part of an impact that decreases greatly over the final portion of the impact. For wood chips, it was observed that impacts would last for several bar crossings and occur periodically with each rotation of the refiner. This is in accordance with earlier high-speed photographic observations of the flow of chips in refiner mechanical pulp refiners.