Patent ID: 6488094
Filing Date: 2002-12-03
Classification: E21B

Abstract:
Apparatus for shutting off upward flow from a conduit supported by a rotary table, said conduit having a threaded joint at its upper end, comprising:a support unit with one or more cylinders extendable and retractable therefrom, said unit having an upper end and a base end; a telescoping stanchion having an upper end and a base end; an oblong plate having a first end attached to the upper end of the support unit and a second end attached to the upper end of the stanchion; a swivel mounted on the upper end of the support unit; a clamping assembly attached to the swivel unit; a safety valve having an open position and a closed position, the safety valve having a threaded lower end for engagement with the threaded joint, the safety valve being vertically disposed within the clamping assembly, said assembly preventing vertical movement of the safety valve within the clamping assembly, while allowing the safety valve to rotate about its longitudinal axis; a carriage assembly attached to the base of the support unit, said carriage assembly resting on a track which directs the linear, horizontal movement of the apparatus toward and away from the conduit; a bar attached to the support unit, said bar having a yoke for resting against the conduit so that, based on previously-made measurements, the longitudinal axis of the safety valve will then be aligned with the longitudinal axis of the conduit for threading the end of the safety valve into the threaded joint; drive means for vertical movement of the clamping assembly.