SELF-ADJUSTING CASING-HEAD STUFFING BOX Russian patent published in 2000 - IPC

FIELD: sealing of wellhead of oil wells operated with sucker-rod pumps. SUBSTANCE: self-adjusting casing-head stuffing box includes braden-head with spherical support, crossing having axial hole, upper axial spherical recess and shoulder with male thread. Crossing bottom has branch pipe with thread for tubing pipes, spherical support having hole with tuning thread. Tee joint is connected with braden-head by spherical support and with crossing by two spherical joints secured by cap nuts and locknuts and having sealing parts and antifriction rings. Tee joint has branch pipe at its top. Branch pipe has axial spherical recess and bead with male thread. Tee joint has branch pipe at its bottom with thread for tubing and discharge hole. Threaded parts are rotated by bushings, and braden-head and crossing by hexahedrons. Crossing with support and braden-head may be inclined in spherical joint round their centers that allows braden-head to be left-adjusted with respect to polished rod in its radial displacements and inclinations within inner diameter of well upper tubing pipe. EFFECT: increased operating reliability of upper part of well pipe string, reduced wear of sealing members and guide bushings of braden-head, upper coupling of pipe string and internal surface of tubing upper part. 3 cl, 1 dwg