Abstract: A ribbed construction assembled from sheet metal bands for improved heat transfer, suitably built into the pipes of heat exchangers forms the arrangement of the invention. The ribbed construction assembled from toothed metal bands ensures the improved heat transfer primarily by slowing down the velocity of the medium flowing in the center of the pipe; furthermore it improves the temperature distribution of the flowing medium by means of metallic contact and mixing. Although the ribs are easily movable in the pipe, a significant portion of the tooth-ends is in loose contact with the inner pipe wall, which likewise improves the heat transfer.