A process for the formation of a sealing and corrosion protection film on the inner surface of the armature

摘要

1,153,524. Pipes. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 16 Jan., 1967 [17 Jan., 1966], No. 2145/67. Heading F2P. [Also in Divisions C4 and C5] A method for the internal treatment of gas pipe-lines, e.g. to prevent leakage at socketed joints, comprises mixing a treating agent with a liquefied gas and spraying the mixture through a nozzle into the lines by means of its own vapour pressure. Suitable treating agents are hydrocarbon oils, e.g. lubricating oils boiling above 300‹ C. (naphthenic oils being preferred), mixtures of distillation residues of mineral oils with aromatics, e.g. asphaltic bitumen with benzene, and aromatics alone, e.g. benzene or its homologues. Suitable liquefied gases include propane and butane, and halogenated hydrocarbons, e.g. methyl chloride. The treating agents, which are preferably soluble in the liquefied gas, may incorporate packing activators, revivers and preservers, surface-active agents, anti-corrosion agents, dust-binding or wetting agents, and coating agents, e.g. bitumens, paints and resins. The method is preferably carried out while gas is flowing in the line.