Hollow roller especially suitable for finishing fibrous web in papermaking industry, has cavity filled with large smooth and small particles, lubricated with graphite

摘要

The cavity (3) in the roller is at least part-filled, by solids alone. These are particles, especially with rounded surfaces. They are spheroidal or ellipsoidal. They are steel, especially steel balls. Packing density of the particles exceeds 4000 kg/m3. Their diameter is 1-4 mm. The cavity is completely filled with them. It also contains finely-dispersed solids with grain sizes preferably less than 1 mu m, which at least partially fill it. Their volume occupies less than 15% of that occupied by the large solids particles. The cavity also contains solid lubricating particles e.g. of graphite. This amounts to less than 10% of the volume of the large solids particles. The solid particles are coated with solid lubricant. Only some of the solid particles, preferably 10% to 60% of them, are coated with the lubricant. The weight of all solids together, is preferably at least 10% of the roller (1, 2) weight. A corresponding calender for smoothing a paper, card, tissue or other fibrous web, includes rollers, of which at least two are constructed as described.