| 摘要 |
MINERAL INSULATED CABLE MANUFACTURE In a method of manufacturing mineral insulated cable in which the metal tube from which the sheath is to be formed is formed from an advancing metal strip which is folded into tubular form and whose edges are continuously welded together, any defects in the weld are identified and located by continuously introducing ultrasonic vibrations into the welded region. These vibrations either interact with a defect in the welded region to produce an echo or undergo a change in signal strength arising from transmission past a defect. The advancing tube is continuously monitored to detect any echo or change in signal strength caused by a defect and, in response to any such identification, the advancing tube is automatically marked to indicate the location of the defect.
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