GB1366521A - Device for cutting holes in walls of pipelines or pressure vessels - Google Patents

Abstract

1366521 Cutting holes in pressure apparatus SPETSIALNOE KONSTRUKTORSKOE BJURO-MOSSTROI 1 Oct 1971 45785/71 Heading B3C A device for cutting holes in the walls of pressure pipe-lines or vessels 12 comprises a chamber 4 adapted to be mounted in pressuretight manner to the wall of the pipe-line or vessel, as shown by means of housing 5 welded to vessel 12. The chamber is provided with a fluid outlet, e.g. bleeder valve 6 and a spindle 1 having cutting means, drill 2 and cutter 3, is supported for rotation and axial sliding movement in the chamber. The spindle is slidable with respect to two coaxial gear-wheels 15, 16 and rotates with the first wheel 15. A common transmission shaft 21 carries a worm-wheel 28, driven by worm 27 connected to a drive motor and third and fourth gear-wheels 17, 18 which are in mesh with the first and second gearwheels 15, 16 respectively and rotatable with the worm-wheel 28. The gear ratios of the first and third 15, 17 and second and fourth wheels 16, 18 are different so that on rotation of wormwheel 28 there will be slow relative rotation of the wheels 15, 16 which are connected respectively to spindle 1 and to a nut member 24 which runs on a screw-member 25 detachably keyed to shaft 1 so that the relative movement of the wheels 15, 16 feeds the spindle axially. The nut member 24 is detachably coupled to wheel 16 by means of, for example, a carrier member 26 with bayonet type slots which engage projections on member 24 (see Fig. 2). In use where a branch pipe 11 is to be connected to vessel 12, housing 5 is welded to the vessel and chamber 4 mounted on top. Spindle 1, not provided at this stage with screw mechanism 24-26, is raised to the upper portion of chamber 4 and stuffing box seal 7 is tightened. Spindle 1 is lowered and the mechanism 24-26 added. The hole is cut, drive disconnected and mechanism 24-26 removed. Spindle 1 is raised by the released pressure and a flap valve 9 is closed by means of cable 10. Pressure in chamber 4 is released by valve 6.