The present invention concerns a method and an apparatus for gravimetric metering of a powdery bulk material, said system comprising a storage container accommodating the bulk material, a feeding pipe for feeding bulk material from the storage container to a dosing container, a dosing discharge device for continuously discharging bulk material from the dosing container to a discharge pipe and on to a discharge line, wherein said dosing container is mounted on at least one weighing cell, and wherein the feeding pipe is provided with a first flexible tube member and the discharge pipe is provided with a second flexible tube member, and wherein the first flexible tube member comprises a first compensator and a second compensator with a tubular member there between.