GB224313A - Improvements in or relating to drying or heating apparatus - Google Patents

Abstract

224,313. Schmidt, O. Aug. 20, 1923. No Patent granted (Sealing fee not paid). Rollers, hollow.-A roller for drying or heating apparatus, heated internally by steam, comprises a series of independently mounted electrical heating elements which generate the steam within the roller. The roller is provided with six metallic tubes c fixed tightly in holes in its ends, and each having screwed into it two silica tubes f containing heating coils g connected to brush terminals h making wiping contact with rings i, j, k. The rings i are connected to one supply main, and the rings j, k to the other. One terminal of each coil makes contact with a ring i, while at each end two of the other terminals make contact with a ring i and the other four with a ring k. Switches allow two, four, or six pairs of coils to be heated. The roller contains water through which the coils pass in turn; an inlet m, a drain cock o, and a safety valve are provided. The heating of the drying rollers in a paper making machine may be individually regulated. The rings j, k may be replaced by a single ring divided into insulated sectors any of which may be cut out of the circuit; or the temperature may be controlled by a rheostat. In a modification, the ends of the roller are integral with hollow trunnions rotating on a shaft, the middle portion of which is formed as a hollow drum carrying brackets which support the coils. In a further modification, a cylindrical wall of heat-insulating material confines the steam and water to the annular outer portion of the roller interior, and water may be supplied and stream discharged through a stationary hollow shaft provided with valves.