SPHERICAL CIRCULAR ROTARY PREVENTER Russian patent published in 2014 - IPC E21B33/06 

FIELD: oil and gas industry.

SUBSTANCE: spherical circular rotary preventer contains a case with the central feedthrough hole and a circular bore where a piston and a base plate are placed between the piston and case. In a wall of the circular bore there are hydraulic channels for interaction of its cavities with a hydraulic drive. At the case there is a cover with a radial stopper in it and a flange with the central feedthrough hole installed hermetically in its central threaded opening. A rotatable hollow shell is placed at rolling contact bearings. The upper bearing with the central feedthrough hole is connected hermetically to the upper part of the shell cavity; it contains a spherical groove. Under the upper bearing there is a lower bearing with the central feedthrough hole, which is installed hermetically at the piston butt end and is rotatable at rolling contact bearings and sleeve bearings; it interacts hermetically with the lower part of the shell. A sealing element is placed between the upper and lower bearings and interacts by its upper part with the spherical groove in the upper bearing and by its lower part to the butt end of the lower bearing.

EFFECT: increase in total life between overhauls, improvement in reliability and safety of operation as well as reduction of operation costs.

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