DIE PREVENTOR Russian patent published in 2011 - IPC E21B33/06 

FIELD: oil and gas production.

SUBSTANCE: die preventor consists of case with covers having two rods secured in each cover, and with pass channels and cavities wherein there are installed dies with sealing elements. Pair of knives is arranged on the dies, while the knives installed in the case are made in form of a ring. Upper knives of both dies are set off to a side of the pass channel of the case at a distance equal to half of external diametre of packed pipes. The die preventor is equipped with mechanisms of die fixation. Each mechanism consists of a shaft-gear positioned in the case of the case and rotating around its axis, of two arresters with thread on internal surface of each; this thread engages thread made on external surface of each of rods of a hydro-drive and connected with tooth coupling to the shaft-gear; also, the mechanism consists of two-half-bushings and an elastic member, made in form of a ring, arranged on each of rods.

EFFECT: disclosed die-preventor facilitates all three kinds of operation for sealing wellhead due to implemented system of rods and hydro-cylinder, also it decreases required working pressure in system of hydraulic drive for cut of drilling tool.

5 dwg