TOTALLY SUBMERGED PRESSURIZED PULP WASHER AND METHOD OF OPERATION THEREOF

摘要

A pulp mat is formed on a surface of a permeable rotating drum disposed in a pressurized liquid filled washing apparatus. Pressurized washing liquid is delivered under the force of gravity or a hydrostatic head from a wash liquid reservoir. The wash liquid reservoir includes both wash liquid and gas supplied from a filtrate reservoir. The gas/liquid interface in the wash liquid reservoir is hydraulically disposed above the top of the washer vat to thereby provide a hydrostatic head between the wash liquid reservoir and the washer vat. The interface is monitored and used to control the speed of the rotating drum. In the event the gas/liquid interface rises above a predetermined optimum value for the current operating speed of the drum, the speed of the drum is increased in order to avoid mat collapse and optimize washing efficiency. In the event the gas/liquid interface drops below a predetermined optimum level, the speed of the drum is reduced to increase washing efficiency.