EXPANSION JOINT Russian patent published in 2001 - IPC

FIELD: expansion joints for compensation of extension of tubing strings - components of downhole equipment for steam injection into oil formation. SUBSTANCE: expansion joint is made in the form of telescopic device including external and internal pipes, gland unit with tightening threaded bushing. Installed in groove of guide bushing rigidly secured inside external pipe is key. Internal pipe external surface has groove for said key with such a length which ensures preset motion of expansion joint. Said joint allows transmission of torque from external pipe to internal pipe by means of sliding key in any point over entire length of expansion joint motion. End surface of threaded bushing of packing has projections, and surface of external pipe facing end of threaded bushing has hollows corresponding to projections of threaded bushing. It makes possible to tighten or to release sealing collars of gland unit. EFFECT: extended functional potentialities of expansion joint and its adequate sealing. 2 dwg