Roller for the thermal treatment of a web of material, and the use thereof

摘要

For treating a web of material, for example for smoothing a paper web, an externally heated tubular roller (1) is used. To reduce the heat flux between the outer surface and the inside of the shell (6), where there are heat-sensitive components (3), the roller shell is built up from a plurality of concentric radial zones (9, 10, 11), at least one of the zones, for example the middle zone (11), consisting of a heat-insulating material of low thermal conductivity. This heat-insulating zone (11) can, for example as a continuous layer, consist of ceramic, porcelain or heat-resistant plastic, or of individual pieces of such material with interposed air- or gas-filled chambers, or of continuous air- or gas-filled grooves or channels, where the latter can be filled by a porous material. <IMAGE>