Patent UA-65508-C2 (UA)
Title: Method for repair of polyethylene pipelines with use of thermo-resistor muffs
Inventor: DUBAS PETRO ANDRIIOVYCH
IPC: F16L47/00
Filed: 2003-12-26
Abstract: A method for repair of polyethylene pipelines with use of thermo-resistor muffs is implemented through termination of gas supply at the damaged section of the polyethylene pipeline, with provision of access to the defect section of the polyethylene pipeline, with cutting the defect section of the polyethylene pipeline, cleaning from dirt of the ends of not damaged sections of the polyethylene pipeline, with preparation of polyethylene insert with same diameter, implementation of preliminary activation of the working zone, installation of polyethylene insert to the place of the defect section of the polyethylene pipeline, provision of coaxiality of connection of the polyethylene pipeline and the polyethylene insert with the following tightening of the joint sites for the pair of the ends of the sections of polyethylene pipeline and polyethylene insert through welding polyethylene insert with butt joint. At that, the preliminary activation of the working zone is carried out as mechanical treatment and the following degreasing. To connect the polyethylene pipeline and the polyethylene insert, one uses the connection elements as thermo-resistor clutches or thermo-resistor parts in the cylindrical body of which one palaces the electro-conductive spiral; the ends of this one are provided by a pair of terminals placed in one of the walls of the body; at that one arranges through technological openings in the walls of the cylindrical body and normally to its long axis. After that one determines the limiting values of electric resistance of the thermo-resistor muffs of thermo-resistor parts depending on the inner diameter of the body of the thermo-resistor muff or thermo-resistor part. One installs to the pair of ends of the polyethylene pipeline with slide fit a pair of thermo-resistor muffs or thermo-resistor parts, with placement of the polyethylene insert at the place of the defect section of the polyethylene pipeline, with its installation at butt joint at the other ends of the thermo-resistor muffs or thermo-resistor parts, with provision of slide fit of the joints and, having closed with the bodies of the thermo-resistor muffs or thermo-resistor parts the placed of joint of the polyethylene pipeline and the polyethylene insert, one provides tight fit of the placed of joint of the polyethylene pipeline and the polyethylene insert with the inner surface of the thermo-resistor muffs or thermo-resistor parts. Tightening of the joint of the ends of the polyethylene pipeline and the polyethylene insert one performs through implementation of the process of thermo-resistor welding as joint melting of material of the inner surface of the pair of thermo-resistor muffs or thermo-resistor parts and the outer surfaces of the polyethylene pipeline and the polyethylene insert at both sides of the place of the joint, with application of constant voltage to the pair of terminals of the thermo-resistor muffs or thermo-resistor parts from a controlled electric power source; and after termination of application of constant voltage one controls the time of cooling of the welded joints; at that the parameters of the process of thermo-resistor welding and the time of cooling of welded joints are chosen depending on the type and the dimensions of thermo-resistor muffs or thermo-resistor parts and the electric resistance of those. This invention makes it possible to increase effectiveness of implementation of repair of polyethylene pipelines.