METHOD OF APPLICATION OF POLYMER PROTECTIVE COAT ON INSULATED SURFACES OF WELDED JOINTS OF STEEL PIPE LINES PROVIDED WITH POLYMER COATS UNDER FIELD CONDITIONS Russian patent published in 1999 - IPC

FIELD: erection of pipe lines. SUBSTANCE: method includes preliminary heating of surface to be insulated, application and forming of thermoplastic adhesive layer followed by application and molding of at least one polymer protective coat. Simultaneously with preheating of surface to be insulated, adjoining polymer coat made at Manufacturing plant is subjected to heating. For preheating the surface to be insulated, use is made of gas infra-red burners evenly distributed over entire surface; adjoining polymer coat made at Manufacturing plant is heated by means of exhaust gases of these burners. Prior to application of polymer protective coat on thermoplastic adhesive layer, intermediate layer made from material possessing high adhesive properties relative to material of thermoplastic adhesive layer and relative to material of polymer protective layer is applied and molded. Molding each of above-mentioned layers is effected through holding its material at stable moulding temperature during entire molding period till its complete cross-linking. Sevilene is used as powder-like adhesive material and thermal and light-stabilized polymer is used as polymer material. Layers are applied by flame spraying. EFFECT: enhanced reliability of corrosion protection of welded joints in pipe line. 18 cl, 4 dwg