The present invention relates to a device for dewatering material suspensions. It comprises two cylindric rotary rolls (1) where at least one of the rolls (1) is liquid permeable. The rolls (1) form between themselves a nip (2), through which the material is intended to pass downward from above while being dewatered at the same time. The invention has the object to solve the problems of pressed-out liquid (filtrate) re-wetting the material. For the liquid permeable roll (1) below the nip (2) at least one abduction surface (20) extending along the entire roll (1) is located along which surface at least parts of the filtrate are intended to run. The filtrate is led into a gill (17), which extends along the entire length of the roll (1) and comprises a liquid inlet (18) and a return flow protection (19).