Apparatus for humidifying a web material

The apparatus (10) to wet a web material (12), especially of paper or cardboard, only covers the edges of the web (12) so that the edges alone are moistened. The edges of the web (12) are covered at both sides, for both sides of the web to be wetted by the U-shaped wetting units (14) round each web edge (16). The unit covers an edge strip of the web (12) which is 10-15 cm wide, in the same dimensions at both sides of the web. The two legs of the wetting unit U-profile can swing in relation to each other, to give an opening for the insertion of the web (12) and then close over the inserted web. At least one wetting unit (14) is a heated steamer, with a double mantle, and a take-off for condensation and a steam suction extraction. The wetting units (14) extend along the line (L) of web travel, and in a length to give the web a dwell time of at least 0.3 ms within the wetting units (14).