Abstract: The present invention relates to a system and a method of extracting liquid from a humid mass by compressing same. The system comprises a conduit of linear, circular or other shape through which the humid mass is displaced. The conduit is of rectangular cross-section, which cross-section can be constant or variable. Further, the conduit has perforated side walls along at least a liquid extraction working section of the conduit. The system further comprises elements which cause an axial pressure at the interior of the humid mass as well as a mechanism to displace at least one of the perforated side walls to convey the humid mass along the working section of the conduit in such a way as to generate between the interior surface of the perforated side walls and the humid mass a dynamic friction force which defines a pressure zone which is less than the axial pressure created by the pressure creating elements.