High pressure tapping apparatus.

摘要

The apparatus comprises an elongated tapping machine body having a device on the lower end for attachment to a pipeline that is to be tapped and a feed screw positioned longitudinally inside the tapping machine body that rotates about its longitudinal axis. It has a boring bar connected to the feed screw for axial movement relative to the boring bar upon relative rotation of the feed screw and boring bar, the boring bar having device for attachment to a cutter for rotation by the boring bar and for movement by the boring bar into and out of engagement with a pipeline. It has a device for rotating the feed screw and a device for rotating the boring bar to tap a pipeline when moved into engagement with it by the relative rotation of the feed screw and the boring bar. It also has a device for sensing pipeline pressure and a control member to control hydraulic fluid pressure inside the tapping machine body based upon the pipeline pressure to at least in part balance the forces applied to the boring bar.