Abstract: A material web drier containing a device for controlling the gas flow of a drying medium as a function of the actual state of the wet material web which is to be dried, comprising nozzle casings or surfaces containing blow-out or discharge openings arranged in cooperating relationship with respect to the material web. The discharge openings are directed towards the material web and serve for blowing-out the drying medium onto the web. For the purpose of dosing the gas flow or stream effluxing at the nozzle casings or surfaces, there are provided opening and closing elements which free the discharge openings or partially or completely close the same, as desired, whereby it is possible to vary the impingement of the material web by the drying medium selectively at discrete locations or regions thereof, both in the lengthwise and transverse directions of such material web.

Abstract: The grooves of the drying cylinder are provided with turbulence producers in the form of U-shaped inserts, split rings, perforated strips or bands, and lattice-like wire strips in order to create turbulence in the otherwise laminar flow of condensate. This turbulence eliminates the heat insulating effect of the condensate. The turbulence producers are spaced from the base of a groove by at least 0.5 millimeters while the maximum spacing of the internal surface of the producers from the groove base is 10 millimeters.