| 摘要 |
In a procedure for washing cellulose in a drum a continuous web is conducted through a plurality of mutually separated washing zones and in the procedure the pure washing liquid is introduced at the washing step which is last in the direction of travel of the web. This liquid displaces suspension fluid contained in the web and the latter is urged with the aid of a drained fluid pipe system to a washing step located upstream in the web's direction of travel and the displaced suspension fluid repeats the displacement washing process performed by the pure washing liquid in the last washing step. This procedure is repeated until each washing step has received a flow of washing liquid. To utilize the concentration raising capacity of the washing procedure and apparatus, before discharging the pulp, part of the drained fluid pipe system is emptied and the drained fluid therefrom obtained is returned to an earlier washing step. |
