Abstract: An apparatus is used for both repair of operating pipelines and protection of newly built pipelines and comprises a cleaning tool (1) which is caused to move in the interior of the pipeline (5) under the action of a flow of fluid containing a dissolved inhibitor. The cleaning tool comprises a hub (3) on which blades (4) are secured in two rows to engage the pipeline surface. The blades (4) are displaced with respect to one another so that the angle between two adjacent blades is from 10.degree. to 25.degree. to define apertures along the periphery of the cleaning tool through which jets of fluid can flow to remove a part of deposits and to impregnate the remaining layer with the inhibitor dissolved in the fluid as so to form a protective coating. A support member (11) carrying an impact-type alarm member is mounted on the cleaning tool (1) so as to facilitate location of the apparatus in the pipeline and to maintain the apparatus in a desired position.

Abstract: A method of removing deposits from the inside surface of a pipeline and applying a protective coating thereto includes cleaning the pipeline inside surface and treating this surface with a solution of corrosion inhibitor to form a coating on the pipeline inside surface followed by a subsequent treatment with a solution of corrosion inhibitor to maintain the strength of the coating thus applied. The method provides for cleaning of the inside surface by jets of liquid which produce a pressure differential between the core of deposits and their surface to separate the deposits from the pipeline walls, while simultaneously impregnating the remaining layer of deposits with a solution of corrosion-promoting agent and subsequently impregnating the layer with a solution of corrosion inhibitor to form a coating.