Introducing screw for biogas plants

A screw conveyor for introducing organic matter into a biogas digester that is under internal gas pressure, said screw conveyor comprising:

• a screw pipe extending in a longitudinal direction and having an inlet opening for organic matter in the region of a first screw pipe end, and an outlet opening for the organic matter in the region of a second screw pipe end, and an inner wall,
• a conveying screw (i) extending in the longitudinal direction, (ii) arranged inside the screw pipe, and (iii) which is made to rotate by a screw conveyor drive, for conveying the organic matter in a conveying direction, and spaced from the inner wall so as to form a passage cross-section, and
• a digester connector for connecting the outlet opening directly to the biogas digester,
• wherein the screw pipe comprises a plug section in a region between the inlet opening and the outlet opening for compacting the organic matter in order to reduce any passage of gas through the screw conveyor, and
• wherein the plug section has an expansion region in which the passage cross-section increases in the conveying direction, and a contraction region disposed downstream from the expansion region, in which the passage cross-section decreases in the conveying direction.