Gas tightly sealed joint in oil field tubular goods

摘要

A pin member with conical thread is threaded into a box or sleeve member having matching conical threading with abutment of the end of the box or sleeve against a shoulder on the pin member; that shoulder is continued into a groove in the pin member receiving a conically distorted polytetrafluoroethylene ring sealingly cooperating with a frustoconical surface of the box or sleeve member near its abutment end. The ring has been placed into the groove after having been heated to a temperature above the crystalline/amorphous transition temperature but below the liquification and decomposition temperatures.