CHEMICAL MASS DRYING BOX WITH BLOWER BOXES

摘要

A cellulose pulp drying box for drying a web (18) of cellulose pulp comprises a lower blow box (26) for blowing gas upwards towards the web (18) via blow openings, for drying the pulp in accordance with the airborne web principle. The lower blow box (26) comprises a central zone (58) comprising blow openings (70, 72) forming a first type of perforation, and a first lateral zone (52) comprising blow openings (70, 80) forming a second type of perforation, the second type of perforation being different from the first type of perforation. The blow openings (72) of the central zone (58) forma first degree of perforation, and the blow openings (80) of the first lateral zone (52) form a second degree of perforation which is larger than the first degree of perforation. As alternative to or in combination therewith the first lateral zone (252; 352)comprises blow openings (70; 370) arranged to form an air cushion above the lateral zone (252; 352) to lift the web (18) adjacent to a lateral edge (82) thereof.