PIPE STRING COUPLING Russian patent published in 2006 - IPC E21B17/05 

FIELD: oil production industry, particularly protection means for tubing string, casing pipe and sucker rod, namely adapted to decrease resilient deformations in weak sections of submersed centrifugal pump to be lowered in deviated well.

SUBSTANCE: coupling comprises body, fixed half-coupling and sliding half-coupling, which is movable relative the body and has spherical outer surface. The fixed half-coupling has spherical inner surface and is screwed into the body. Lower body part is provided with inner spherical surface mating lower part of spherical outer sliding half-coupling surface. Spherical surface of sliding half-coupling is provided with grooves for sealing means receiving and through orifices adapted to connect the grooves with inner surface of sliding half-coupling. Adjusting screws to be inserted in blind smooth orifices formed in sliding half-coupling are arranged in the body. The blind orifice diameters provide sliding half-coupling displacement in azimuth plane without interference in its angular movement relative transversal axis. Annular space between the body and spherical surfaces of half-couplings is filled with graphite grease. Upper part of sliding half-coupling is provided with flat face.

EFFECT: increased operational efficiency of downhole pumping equipment, reduced bending stresses in tubing string, coupling and casing pipe sections arranged in intervals of well deviation increase, improved dynamic pumping equipment characteristics, service life and prevention of fatigue corrosion along with simplified coupling structure.

1 dwg