Method and a press for compressing material having two opposed transfer elements exacting a greater pressing force on the material during a forward motion than the pressing force exerted during a return motion

A method for pressing a material, comprising the steps of:

• feeding the material into a gap formed between two pressing surfaces, in which gap the cross section of the material flow is tapered in the forward transfer direction of the material;
• compacting and pressing the material between the pressing surfaces formed by parallel, beam-shaped transfer elements;
• reciprocatingly moving the transfer elements in the direction of the material flow such that the mutually opposed transfer elements of both pressing surfaces are moved in a mutually synchronized manner in the same direction, the transfer elements being moved in two alternating groups so that every second opposed pair of the transfer elements in turn perform a forward transfer motion, while the interleaved second pair perform a return motion, such that during the forward transfer motion the pressing force exerted by the transfer elements on the material is greater than the positive pressing force exerted during the return motion of the transfer elements;
• cyclically compacting and pressing the material between the transfer elements such that the transfer elements performing the forward transfer motion move the material toward the pressing surface of the opposed transfer elements so that void spaces and liquid are expelled from the material;
• and
• exerting a force to form the material into the gap between the transfer elements by compliant support elements, the material in the gap acting as a compacted plug which prevents the escape flow of liquid from the non-pressed portion of the material to the pressed portion of the material and expands the gap between the lower ends of the transfer elements in accordance with the volume and compressibility properties of the fed material.