Patent ID: 7510219
Filing Date: 2009-03-31
Classification: E21B,F16L

Abstract:
1. A self sealing pressure responsive coupling device for joining two oil field tubular elements having male threaded ends terminating in end faces, the coupling device comprising: a coupling sleeve having female threaded end sections for matingly receiving the male threaded ends of the tubular elements and having an interior longitudinal span between the threaded female end sections, the interior longitudinal span including a central interior seating region of a first inner diameter, said female threaded end sections including a pair of spaced clearance regions of a second inner diameter greater than said first inner diameter; and a fulcrum ring having spaced fulcrum ring longitudinal ends, each having a longitudinal end span length and a central length between the spaced fulcrum ring longitudinal ends and corresponding to the interior longitudinal span of the coupling sleeve, the fulcrum ring central length being less than each of said longitudinal span end lengths and having a radial outer surface engaging the central interior seating region of the coupling sleeve, end faces of the fulcrum ring being engaged by the end faces of the two tubular elements inserted in the coupling sleeve, internal pressures within the fulcrum ring and the tubular elements acting to bend the longitudinal ends of the fulcrum ring radially outwardly into the clearance regions of the coupling sleeve, the radial bending of the fulcrum ring longitudinal ends increasing a metal-to-metal contact force between the end faces of the fulcrum ring and the end faces of the two tubular elements.