High pressure tapping apparatus

摘要

An apparatus for tapping an opening into an existing pipeline that is under internal pressure including an elongated tapping machine body having means on one end for attachment to a pipeline, a boring bar having a rotatable feed screw therein by which the boring bar is axially positioned, and a pressure responsive valve actuated by differential pressure between the interior of a pipeline and the interior of the tapping machine body to control hydraulic pressure inside the tapping machine body to thereby counterbalance the hydraulic force applied to the boring bar.