WELLHEAD SEALING HEAD Russian patent published in 1996 - IPC

FIELD: gas and oil producing industry, wellheads equipment for overhaul carrying out without well killing in particular. SUBSTANCE: wellhead sealing head has body with mounted in it flexible sealing member with supporting bush and piston ring, that forms working chamber of sealing member return in initial state. Sealing member is mounted with capability of forced axial tension and rotation. As a result of sealing member tension value of contact pressure is decreasing between it and surface of running-in pipe and value of their contact area is decreasing. It decreases wear of sealing member and so increases its service life. Having maintained definite balance of working mediums pressures in working chamber and chamber of return, optimal mode of sealing head operation is set for wide range of pipes running in well. During running-in pipes string rotation sealing member is rotating together with running-in pipes using thrust bearing formed by balls located in circumference grooves of ring-type shoulder of body, lower bush and nut, that are correspondingly connected with sealing member. EFFECT: decreased wear of sealing member, increased service life of wellhead sealing head. 1 dwg