| 摘要 |
<p>An apparatus for stabbing and threading a safety valve into a well pipe to prevent upward flow comprises a tubular canister (65) rotatably mounted on a carriage assembly (55) that is slidably mounted on an upstanding frame. The lower end of the frame has a swivel mounting to a bracket that is attached to the side of an elevator-type clamp (12) means by which the apparatus is clamped onto the upper end portion of the pipe. An alignment mechanism (110) moves the frame from a first position wherein the canister is not aligned with the pipe to a second position wherein the canister and pipe are aligned and the safety valve can be stabbed and threaded into the pipe. A variable drive mechanism (180) is operated to cause the canister, and the valve located therein, to be rotated and simultaneously lowered toward the pipe. The drive mechanism may be adjusted to facilitate threading of the valve into a variety of drill pipe thread designs. An improved clamp assembly allows adjustment in its size so as to accommodate drill pipe of various diameters.</p> |
