NOVELTY - The raw material feeder for a biogas plant, comprises an internal container (2) with a base plate and side panels connected with the base plate in a sealing manner, and a conveyer present in the interior of the container. The container is liquid-tightly sealed, is made of corrosion resistant plastic, and is present in a metal frame (1), which supports the static load of the container filled with the raw material. One of the side panels of the container is open. The metal frame comprises flexible elements in two spatial directions. The element provides a quasi-elasticity of the metal frame.    USE - Raw material feeder for a biogas plant, where the raw materials are liquid manure, sewage sludge, fats and plants such as silo corn.    ADVANTAGE - The feeder has improved corrosion resistance and stability thus enabling to feed high-weight raw material into the biogas plant.    DETAILED DESCRIPTION - The raw material feeder for a biogas plant, comprises an internal container (2) with a base plate and side panels connected with the base plate in a sealing manner, and a conveyer present in the interior of the container. The container is liquid-tightly sealed, is made of corrosion resistant plastic, and is present in a metal frame (1), which supports the static load of the container filled with the raw material. One of the side panels of the container is open. The metal frame comprises flexible elements in two spatial directions. The element provides a quasi-elasticity of the metal frame to the extent, to which the frame expands or shrinks itself due to change in external temperatures of the plastic container. The metal frame is constructed with side and base struts (7, 8) in a basket-like manner. The base struts have more load-carrying capacity than the side struts. The flexible elements at the base struts are mounted on corners (10), by which the displacement of the internal dimensions of the metal frame is adjustable. The internal container has an actuator. The quasi-elasticity of the metal frame is reached so that the actuator is engaged in an appropriate device of the metal frame.    DESCRIPTION OF DRAWING(S) - The diagram shows struts of a raw material feeder.    Metal frame (1)    Internal container (2)    Side and base struts (7, 8)    Posts (9)    Corners. (10)