| 摘要 |
<p>Guide for a drill for breaking through the wall of a pipe incorporates a coaxial gland through which the body of the drill bit can pass and a decompression chamber with a radial vent controlled by a stop valve. Suitable for mounting branches on to pipes contg. liq. or gas under pressure while the pipe is drilled. The guide is mounted temporarily on a branch carrying a full bore stopcock and welded on to the main pipe before the guide is fitted; for aluminium or PVC pipes, the branch may be secured on to a saddle seal by a split collar clamped on to the pipe. The decompression chamber allows the swarf to be flushed clear before the bit is withdrawn and the valve on the branch closed. The bit may be driven by a manual crank, via a gear system, or by a pneumatic, hydraulic or electric motor.</p> |
