Tube protection - by alkaline porous layer covered by dense outer cladding

摘要

Powdered polyethylene and chrysotile asbestos at 10 : 1 is hot sintered on to the tube to give a layer with 35 vol. % of pores, and then covered by a dense cladding of pure polyethylene. Should a leak develop, the alkaline character of the intermediate layer protects the steel tube against corrosion, and the porous nature allows pressure testing at regular intervals along the pipeline.