Drying sieve for paper, tissue paper or cardboard is air-permeable at the center and air impermeable at the outer margins

摘要

A papermaking assembly has a drying sieve (1) with a center strip (6) and outer margins (4) that are covered by the fibre web (3). The outer margin (4) is air impermeable and the center strip is air permeable. The outer margins (4) are uncovered. The center strip (6) is flanked by transitional sections (5) that are less air permeable than the center strip. The transitional sections (5) and free outer margins (4) are of the same air permeability. The transitional zone allows for possible width shrink in the web. The outer margin (4) has a different weave to that of the center strip (6) and is closed by a bonding agent or welding.