CASING-HEAD STUFFING BOX ASSEMBLY Russian patent published in 2006 - IPC E21B33/03 

FIELD: oil production industry, particularly operation equipment included in wellhead assembly and means to prevent oil spills between rod and seal.

SUBSTANCE: casing-head stuffing box assembly comprises main body, upper stuffing box body having lid, lower stuffing box body and adjusting unit arranged in cavity. The cavity is defined by main body, lower stuffing box body and coupling nut. The adjusting unit comprises stepped annular piston, as well as lower stiffening box body and stepped annular piston cooperating one with another so that the body and the piston may perform mutual rotation. Inner and outer cylindrical surfaces of lower stiffening box body and stepped annular piston have equal eccentricities. Inner cavities between spaced main body, stepped annular piston and coupling nut are filled with liquid. Lid of upper stuffing box has cavity to be filled with lubricant before stiffening box operation and during operation thereof.

EFFECT: increased operational reliability of casing-head stuffing box.

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