Multi-cylinder dryer for a paper machine with supported draw of web

Abstract

A multi-cylinder dryer for a paper machine having several drying groups situated one after the other, in which drying cylinders are situated one above the other in stacks, preferably in vertical stacks. In subsequent groups, a web is passed from one drying cylinder onto a next drying cylinder by way of a single-wire draw, so that the drying cylinders in the single-wire draw groups are situated outside the loops of their respective drying a wires. The web is passed as a supported draw from one single-wire group to a subsequent single-wire group by using at least two transfer-suction rolls. A first one of the transfer-suction rolls is situated inside a loop of a drying wire of the preceding single-wire draw group. The second or final transfer-suction roll is situated proximate to the first suction roll and inside a loop of a drying wire of the latter or subsequent single-wire draw group, proximate to a first drying cylinder in this subsequent group. Transfer of the web from one wire group to the next wire group takes place with support by a drying wire substantially all the time. At that location, the web is subjected to a difference in pressure that maintains the web in contact with a drying wire, generally a negative pressure being effective from the drying-wire side.