Blow box for use in a plant for drying a material web

摘要

PCT No. PCT/SE96/01277 Sec. 371 Date Jun. 18, 1998 Sec. 102(e) Date Jun. 18, 1998 PCT Filed Oct. 9, 1996 PCT Pub. No. WO97/16594 PCT Pub. Date May 9, 1997A blowbox for use in a plant for drying a material web includes an essentially horizontal box wall having formed therein circular orifices and eyelid perforations each of which includes a slit extending in parallel with the center line of the upper box wall. A depression is formed m the upper box wall adjacent one side of the slit. The eyelid perforations are arranged in two rows and parallel with the center line and together they form a zigzag pattern about the center line that intersects the depressions of the eyelid perforations in both rows. The orifices are disposed in a first and second pair of rows with both rows in each pair positioned on either side of and spaced equally from the center line. The upper box wall has a shallow continuous arcuate shape across its entire width.