Pressure Screen Capacity-Current Findings on the Role of Wire Width and Height

Abstract

The influence of wire geometry on screen plate capacity and accept quality was studied. Ten screen plate geometries differing in slot and wire width, profile height, wire height and accept-side rounding were tested with water and thermomechanical pulp using laboratory equipment. The hydraulic resistance of the screen plates was measured in terms of the pressure drop in the forward and reverse directions and the capacity of the same designs was studied by measuring accept consistency and accept fiber length. The capacity of the screen plate increased with increasing slot width, decreasing wire height or increasing profile height, and also with increasing wire width, despite the decrease in open area. Accept quality was determined in terms of pulp pas-sage, and an increase in capacity was found to reduce separation selectivity. The hydraulic resistances in both the forward and reverse directions proved likewise meaningful for screen plate capacity.