| 摘要 |
<p>A machine for use underwater and therefor subject to ambient hydrostatic pressure for tapping a pressurized pipeline has an elongated tubular tapping machine body with a boring bar therein that receives a cutter at its lower end. A passageway in a lower end portion of the tapping machine body senses the internal pressure of a pipeline after the pipeline is penetrated by the cutter, the passageway being connected to a pressure equalizer having communication with the interior of the tapping machine body to thereby balance hydraulic forces applied to the boring bar during a tapping operation. The machine has a gear case affixed to the tapping machine body to actuate the boring bar, the tapping machine body being sealed from the gear case, and including a fluid isolating equalizer supported to the tapping machine body and having a first communication with the interior of the gear box and a second communication with ambient hydrostatic pressure to thereby at least substantially equalize pressure in the gear box with the ambient hydrostatic pressure.</p> |
