| 摘要 |
<p>A pipeline servicing tool primarily for use as a compact valve removal tool, comprises a fixed crosshead (18) to be mounted on a pipeline end, such as a wellhead spool outlet (3), and a moving crosshead (19) which is axially slidable, the fixed crosshead accommodating an axially slidable and rotatable rod (16) and gripping means (50) for holding the rod, and the moving crosshead having drive means (23,24) for advancing and retracting it to enable rod extension pieces (17) to be fitted or removed, the fixed crosshead also having safety stops (58) movable into the line behind the rod or behind a rod extension to block the path of the rod if the gripping means failed. Preferably, the moving crosshead (19) cooperates with further safety means (60-72) to prevent operation of the gripping means except in predetermined, safe positions. The tool could be useful for operations other than plug insertion, such as milling a valve gate.</p> |
