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A cable entry or exit pipe is formed on a fluid transportation pipeline while in normal operation full of and transporting a fluid under a positive pressure, by a method which comprises the steps: (a) producing two semi-cylindrical shells, one of which carries an oblique branch pipe and has an apert

A cable entry or exit pipe is formed on a fluid transportation pipeline while in normal operation full of and transporting a fluid under a positive pressure, by a method which comprises the steps: (a) producing two semi-cylindrical shells, one of which carries an oblique branch pipe and has an aperture aligned with the bore of the branch pipe; (b) securing in a fluid tight manner around the pipeline the two shells so as to form a reinforcing collar carrying an oblique branch pipe lying at an acute angle suitable for the entry into and exit from the pipeline of a cable; (c) securing in a fluid tight manner to the free end of the branch pipe an isolating valve; (d) securing in a fluid tight manner to the free side of the isolating valve a fluid tight drilling apparatus equipped with a drilling bit; (e) opening the valve and introducing the drill bit through the opened valve into the branch pipe; (f) rotating and progressively advancing the drill bit into contact with and through the wall of the pipeline section; (g) withdrawing the drill bit and closing the valve; and (h) removing the drilling apparatus. Preferably, a liner inserted into the branch pipe between steps (g) and (h) serves as a cable guide.

대표청구항 ▼

A method of forming a cable entry or exit pipe on a fluid transportation pipeline while in normal operation full of and transporting a fluid under a positive pressure, which method comprises the following steps: (a) producing a branch pipe having an end thereof shaped to fit closely around a section

A method of forming a cable entry or exit pipe on a fluid transportation pipeline while in normal operation full of and transporting a fluid under a positive pressure, which method comprises the following steps: (a) producing a branch pipe having an end thereof shaped to fit closely around a section of the pipeline when disposed at a predetermined acute angle thereto, the branch pipe having a bore which is substantially less than that of the pipeline; (b) securing in a fluid tight manner said end of the branch pipe to the pipeline section thereby to provide an oblique branch pipe lying at an acute angle to the pipeline section, which angle is suitable for the entry into or exit from the pipeline of a cable or other line; (c) securing an isolating valve in a fluid tight manner to the free end of the oblique branch pipe; (d) securing a fluid tight drilling apparatus in a fluid tight manner to the free side of the isolating valve, which fluid tight drilling apparatus is equipped with a removable drill bit; (e) opening the valve and introducing the drill bit through the opened valve into the oblique branch pipe; (f) rotating and progressively advancing the drill bit into oblique contact with and through the wall of the pipeline section while simultaneously supporting and guiding the drill bit against transverse displacement thereof by the pipeline wall being drilled obliquely, thereby to form in the pipeline wall an aperture, which aperture has a jagged edge to the bore of the pipeline section; (g) withdrawing the drill bit and closing the valve; (h) producing a tubular branch pipe liner for lodgment in the oblique branch pipe to serve there as a cable guide tube covering said jagged edge of the aperture, the liner having one end shaped and smoothed so as to minimize damage to a cable being fed into or withdrawn from the pipeline through the liner; (i) replacing the drill bit by a driving tool carrying temporarily thereon said branch pipe liner; (j) opening the isolating valve and advancing the driving tool and branch pipe liner through the isolating valve into the oblique branch pipe thereby to engage the branch pipe liner in the branch pipe in a predetermined disposition in which said shaped one end just projects into the pipeline section, covers said jagged edge, and is properly oriented for the passage therethrough of a said cable; (k) securing the liner in the branch pipe in said disposition; (l) withstanding the driving tool through the isolating valve; (m) closing the isolating valve; and (n) removing the drilling apparatus from the isolating valve.