Abstract: In order to control and optimize, without stopping production, bowing in the outer wall of a calender roll in which bowing is produced by the action of pressure on an incompressible liquid enclosed in the roll, the invention proposes that, based on error signals generated from continuous thickness measurements and from at least one other quality characteristic, the temperature of the liquid is controlled and the nip modified to correct for deviations from the correct thickness.

Abstract: A rotatably supported roll (1), which is adapted to form a nip with a second roll, so as to advance therebetween a web of material. The load in the nip between the rolls can be controlled by an adjustable camber. To this end, an interior hollow space (13) is provided in the roll (1), which is filled with an incompressible pressure medium, and put under a controlled pressure, so as to cause the roll jacket (10/12) to bulge radially outwardly. This bulging can be significantly supported and influenced by a predetermined progression of the wall thickness of the jacket (10/12) in the axial direction of the roll.