| 摘要 |
A pipe string in an oil well has a cable 2 slidingly attached along it. It may be necessary to break the pipe string. Apparatus is provided for controlling the position of a fracture in the cable, as it is desirable to break the cable at about the same point. The apparatus comprises a pocket 1 attached to the cable and having a passage through which the cable passes, and upper and lower nipples 5 and 6 attached to the cable in the pocket. The lower face 5' of the nipple 5 is skewed relative to the lower internal face 3' of the pocket and the facing faces (5'', 6') of the two nipples are skewed relative to each other, so bending and kinking the cable when tension is applied. The cable therefore breaks at the bend or kink. The pipe string includes a plurality of such apparatuses located at spaced points along its length.
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