| 摘要 |
A hot-tapping unit for drilling holes into pressurised pipe work / valves, the unit having a balanced drill rod 9 contained within a high pressure lubricator 17. Preferably, the equal balanced pressure within the unit is provided by a lubricator 17 and a closed loop system 1, 7, 10, 13. Self-energising seals may be provided on a seal adaptor flange 1, which helps contain the drill rod. Preferably, the back end of the milling / drill rod is enclosed within the pressure lubricating section 17. The hot-tapping unit preferably comprises a collet chuck 2 to grip the drill rod, the chuck being mounted on a translating carriage 5 slidable on guide rods 3. Sliding of the carriage is preferably by piston 14, while an air motor 6 preferably drives the drill. The length of the drill rod may be extendable, preferably by connecting additional lengths of drill rod (and lubricators). Neutralising the pressure differential prevents the drill rod from being pushed back. |
