Apparatus for pressing, dewatering or filtering

An apparatus for the treatment of sludges, fibrous material suspensions or cellulosic material suspensions by pressing and dewatering or filtering, comprising:

• two circulating filter belts, each belt having a side thereof facing the other belt, between which the material to be treated is made to pass;
• two circulating pressure belts for supporting the sides of the filter belts which face away from the material to be treated, the pressure belts and filter belts forming a belt package wherein the filter belts are disposed between the pressure belts with the material to be treated passing between the filter belts;
• means for circulating said pressure belts and filter belts in a moving direction,
• means for supporting the belt package, which includes enclosing walls forming a tunnel through which the belt package is disposed, said tunnel having an inlet end and an outlet end, and said belt package moving through the tunnel in said moving direction from the inlet end to the outlet end;
• a plurality of sealing members attached to the walls of the tunnel and extending completely around the belt package transverse to said moving direction of the belt package, said members providing a seal between the tunnel walls and the belt package;
• a source of fluid under pressure;
• and
• means for introducing fluid from said source into the tunnel between adjacent sealing members to form compression zones along the belt package whereby fluid pressure may be applied to said belt package to compress the material to be treated.