Jig for drilling hole in pipe under pressure - has adaptor clamped permanently on pipe and is formed with bore closed by valve after piercing hole

摘要

The adapter is clamped permanently around the pipe and enables a hole to be drilled whilst the pipe (4) is under pressure. A gasket (5) seals the face (2) contacting the pipe and, at the opposite end of the adapter, is a gland seal (3) tightened by a screw down cap (13, 14). A central bore (8) passing through this seal and the adapter is sued for inserting a standard drill, the shank contacting the gland seal. After piercing the hole, the drill is partially withdrawn and a valve (12) is closed. This has a stem (10) passing through the adaptor perpendicular to the bore and turned (11) by a key.