| 摘要 |
<p>The invention is concerned with a method for the continuous drying of a paper or other porous web by passing the web by means of a drying felt or wire between two moving, airimpermeable surface elements having good heat conducting properties, which elements enclose the web along its whole width. The surface element contacting the web is heated and the surface element contacting the wire is cooled for evaporating water present in the web and condensing the evaporated water into the felt or wire. The temperature of the liquid used for cooling the surface element to be cooled is maintained above 100.degree.C and the pressure at least at such a level as to prevent the liquid from boiling. Thus, the drying of the web can be carried out at an elevated temperature and under an elevated pressure in a continuous process at production conditions for improving the web characteristics. Preferably the cooling liquid is maintained at different temperatures and/or under different pressures at separate steps of the cooling process. Thus, it is possible to adjust the drying conditions affecting the web characteristics. The invention also relates to a device for carrying out such a method, which device is provided with a cooling space divided into at least two separate cooling liquid compartments positioned one after the other in the direction of movement of the surface elements, the compartments containing cooling liquids having different temperatures and/or pressures, the temperature of at least one cooling liquid being above 100.degree.C.</p> |
