METHOD AND APPARATUS FOR CLEANING AND COATING PIPELINE WALLS

摘要

A pipeline pig adapted to be propelled through a pipeline by a pressure gradient. The pig includes an elongated flexible body having a front end and a rear end. Helically oriented flights circumscribe the body from the front end to a point near the rear end. The body of the pig contains a central aperture extending from the front end to the rear end. At the rear end of the pig an opening is defined communicating with the central aperture and allowing fluid under pressure to enter the aperture. In a preferred embodiment of the pig, an annular ring is spaced between the helically oriented flights and the rear end on the body. The construction of the pipeline pig is such that during its utilization its flights, annular ring and rear end sealingly engage the inner wall of the pipeline. A method for distributing fluid along the interior wall of a pipeline, wherein a quantity of fluid is placed at a locus in the pipeline and exposed at one side to a force acting in an axial and rotational direction. This force will cause at least a portion of the fluid to enter a helical path adjacent the pipeline which will force the material to be coated on the inner wall of the pipeline. As the fluid is coated on the pipeline wall it is exposed to an axial wiping force which smooths out the fluid coated onto the inner wall of the pipeline by removing the excess material.