Patent attributes
This invention is a method and apparatus for making a pressure-containing threaded tubular connection, suitable for remotely operated connection and separation, utilizing electrical heating to reduce the amount of make up torque required to produce reliable preloading of the connection. One aspect of the present invention comprises: 1) a first hub with male threads on its exterior and having a sealing face and axial flow passage, b) a second hub having an axial flow passage and carrying an annular seal which can be mated with the sealing face of the first hub and mounting a rotatable nut having female threads on its interior and integral nut heating means. After stabbing and initial make-up of the connection, the nut is heated and thereby expanded in a controlled manner and the connection retightened. Following cooling, the structural connection is fully preloaded and the annular seal fully compressed so that it seals. Reversing the procedure permits disconnection.
