HEAT-INSULATED JOINT OF PRE-INSULATED PIPELINES, METHOD FOR ITS MANUFACTURE, AND PIPELINE REPAIR METHOD Russian patent published in 2002 - IPC

FIELD: construction engineering; pipeline repairing. SUBSTANCE: method is used for insulating non-split butt joints of pre- insulated polymeric sheath covered pipelines in polymeric shell for heat networks, water conduits, and oil pipelines. Method involves preparation of shrinkable sleeve made of polymeric pipe section and not being treated by corona discharge. Inner bore of sleeve is mechanically enlarged in diameter. Sleeve may be made of radiation treated section of polymeric pipe. Sleeve is installed on joint and pulled onto one of pipeline ends above sheath. Applicators are installed over perimeter of sheath ends. Sleeve is arranged so that it encloses applicators and then it is shrank. Glands and lock plates are installed. Joint is subjected to pressure test and filled with heat insulating material (polyurethane foam). EFFECT: improved reliability and service life of joint. 32 cl, 8 dwg