Abstract: Apparatus is disclosed for dewatering pulp suspensions including a pair of cylindrical rotatable liquid-premeable press rolls forming a nip therebetween, so that the material suspension can pass between the nip to be dewatered and to form a material web, a pair of doctor blades disposed below the nip, each associated with one of the press rolls for removing the material web therefrom, and a sealed casing enclosing at least the upper portion of the pair of press rolls, the sealed casing including an inlet for the material suspension, and the pair of doctor blades being coupled together so that they are movable relative to the nip in order to alter the distance between the pair of doctor blades and the nip when the size of the nip is adjusted.