Abstract: An extracting apparatus comprising at least one screw conveyor divided into cells, in which to form the solidmaterial supply compartment, the drum is extended beyond the conveyor last winding without substantial diameter differential by a circumferential perforated casing which is pervious to the liquid and which extends up to a terminal diametral wall provided with a central supply opening for the solid materials; said supply compartment comprises as many liquid-pervious axial elements for raising the solid materials as there are cell series in the drum; to each one of said axial raising elements is associated a slanting channel for conveying the solid materials from the supply compartment to the last cell in each cell series.