Method and device for drying a fiber web

Abstract

A web drying apparatus, e.g., for a paper web, includes several heatable drying cylinders arranged in at least one row with at least one respective endless loop drying wire and preferably arranged in two rows of cylinders with two respective wires. A wire guide roll is between and offset from two of the adjacent cylinders in the one row. The one endless loop dryer wire carries the web thereon on a first part of the web loop path from the first cylinder to the wire guide roll. There the web separates from the wire and travels to a second cylinder in the second row. The wire wraps around the wire guide roll and returns on a second part of the web loop path to the next cylinder in the first row, without supporting a web. On the path between the first and third cylinders and around the wire guide roll, the wire defines a loop. An air guide box and a blower are arranged within the loop. The air guide box produces a vacuum at the first part of the wire loop path for drawing the web against the wire. An air channel extends between the air guide box and the blower. At least one drive nozzle outlets into the air channel. The air channel draws air out of the first part of the loop path to create the vacuum there. The blower directs a stream of air through the wire, at the second part of the wire loop path, and then to a pocket outside the second loop part. The drive nozzle and the blower are supplied by independently controlled flows of blown air.