Abstract: A process and apparatus for controlling the surface temperature of a drying cylinder of a paper machine, in which air may be admixed with the steam introduced into the drying cylinder to adjust the partial steam pressure. The mixture ratio of air and steam is controlled as a function of the measured temperature of the mixture discharging from the drying cylinder. Also, pressure measurements are made of the pressure in the infeed and discharge lines of the cylinder, and valves control this dependent on the measurements. The valves are controlled to provide all steam to the cylinder above a predetermined minimum pressure in the cylinder below 1 bar and to provide a mix of air and steam below the predetermined minimum pressure. Arrangements for controlling one cylinder at a time, several cylinders together for supply of both steam and air, or several cylinders for controlling respective separate supplies of air and with one supply of steam are disclosed.

Abstract: The end portions of a rotary shell forming part of a calendar roll can be heated or cooled by a suitable (gaseous or hydraulic) fluid which is admitted into axially parallel first channels of the shell. Such channels can extend from end face to end face of the shell or only in the region of one end face each. The first channels receive the fluid from second channels which extend radially inwardly to the internal surface of the shell, and spent fluid is admitted into third channels which extend from the respective first channels to the internal surface of the shell. The first channels accommodate axially adjustable throttles which are used to regulate the rate of fluid flow in the shell and to thus regulate the temperature of the respective end portions of the shell.

Abstract: In a ski being equipped with metal edges, the tread (2) has, as seen in a cross section, a horizontally extending central area (2') and at both sides thereof lateral areas (4) extending in upward direction and being rigidly connected with the ski. The width of the central area (2'), extending, as seen in a cross section, in a horizontal plane, of the tread (2) is greater than the total width of the chamferred and upwardly extending areas (4) and the tangent lines applied to the lateral areas (4), extending at least over the width of the steel edges, and normally extending relative to the longitudinal direction of the ski include one with the other an obtuse angle of 170.degree. to 179.degree., preferably 174.degree. to 178.degree., having its apex located below the tread (2) in the vertical longitudinal center plane (6) of the ski. The width of an upwardly extending lateral area (4) of the tread (2) is smaller than 10 mm. This width can approximately correspond to the width of a steel edge.