METHOD OF PERMANENT SLEEVE JOINTING OF PIPES PROVIDED WITH INTERNAL THERMOPLASTIC COATING Russian patent published in 2001 - IPC

FIELD: petroleum and gas producing industry; housing and municipal services. SUBSTANCE: method may be used for building and repair of pipelines transporting chemically-corrosive liquids and gases. Circular groove is made in middle part of insert external surface. Ring of thermoplastic material to be welded with internal thermoplastic coating of pipes is formed on said groove. Contacting surfaces of thermoplastic-material ring, insert, and internal thermoplastic coating of pipes are sealed additionally by squeezing in radial direction during sleeve jointing of pipes. In addition, bead is made in middle part of external surface of ring manufactured of thermoplastic material. External diameter of bead is larger than internal diameter of pipes provided with internal thermoplastic coating. Contacting surfaces of thermoplastic-material ring, insert and internal thermoplastic coating of pipes are jointed to one another by welding or gluing. EFFECT: enhanced reliability of anticorrosive protection. 3 cl, 2 dwg