Apparatus and method for treating a material web

Apparatus for treating a material web, comprising:

• at least one nip through which the material web is guided and which is formed between a roll and a cover of a shoe roll, the roll being heatable to at least 120° C., the roll and the cover of a shoe roll having the same direction of movement as the material web;
• a box which bounds a space through which the material web is guided being arranged after the nip in the direction of movement of the material web, at least one wall of the box being heated to at least 100° C.;
• said at least one wall being arranged above the web in a direction of the force of gravity;
• the box being at least partly thermally insulated with respect to its surroundings;
• a blowing device which conveys fresh air into the space;
• a sensor connected to the blowing device for determining the relative humidity in the space;
• a first seal for sealing off the box with respect to the roll, said first seal bearing on one of, the roll or the cover of a shoe roll;
• a second seal for sealing off the box with respect to the cover of a shoe roll, said second seal bearing on one of, the roll or the cover of a shoe roll;
• and
• a support for supporting, in the region of the second seal, the cover of a shoe roll, so that the cover of a shoe roll in the region of the second seal has a defined position in relation to the second seal.

Method for treating a material web, comprising:

• guiding the material web through a nip formed between a first revolving, heated surface and a second revolving surface;
• heating the first surface to at least 120° C.;
• and
• guiding the material web, after leaving the nip, through a space which is partly bounded by the heated surface and in which a steam atmosphere is produced with the aid of the material web.

Method for treating a material web, comprising:

• guiding the material web through a nip formed between a first revolving, heated surface and a second revolving surface;
• heating the first surface to at least 120° C.;
• the guiding of the material web, after leaving the nip, being through a space which is partly bounded by the heated surface and in which a steam atmosphere is produced with the aid of the material web;
• blowing fresh air into the space;
• determining the relative humidity in the space;
• limiting the relative humidity to at most 99% by blowing in fresh air;
• heating at least one boundary wall of the space;
• sealing off the box with respect to the first revolving, heated surface, by way of a first seal, and with respect to the second revolving surface, by way of a second seal;
• and
• supporting the second revolving surface, so that, the second revolving surface in the region of the second seal has a defined position in relation to the second seal.