Mechanical modification of softwood pulp fibers using a novel lightweight vertical bar plate

Abstract

Refiner plates made using sand casting have a draft angle, which results in a trapezoidal bar shape. These trapezoidal bar plates have a limited throughput compared to the vertical bar plates, and eventually the edges of the bars become dull, resulting in longer time to reach the target freeness and shorter service life. The new lightweight refiner plate with a bar insertion method into a plate base was developed by selecting an aluminium-based alloy as the plate base material and a stainless steel alloy with high wear resistance as the bar material. The lightweight plate with sharp bar edges was very effective in reducing refining energy by reaching the target freeness faster than the sand-cast bar plate. Finally, the lightweight sharp bar plate, which weighed only about half the weight of the cast bar plate, was expected to significantly contribute to easy replacement, improved paper quality, and larger throughput without excessive loss of fiber length. Application: By combining aluminum alloy and stainless steel alloy, a lightweight vertical bar plate suitable for softwood pulp was introduced. The lightweight vertical bar plate has a sharper bar edge, unlike the general cast plate, and it allows a large amount of material to pass, which is much more advantageous in terms of energy saving and production. In particular, even if the bar surface wears out during the continuous refining process, the sharpness of the bar edge is maintained and the life of the plate can be extended.