Welding and other operations during J-lay pipelaying

Patent metadata

Field	Value
Publication number	US-10279412-B2
Application number	US-201113521727-A
Country	US
Kind code	B2
Filing date	Jan 10, 2011
Priority date	Jan 11, 2010
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

A turntable assembly for performing welding or other operations in a pivotably-mounted J-lay tower is disclosed. The assembly includes an annular turntable supported by a base frame to turn about a pipe string in use and a tilt-compensating mechanism acting on the base frame to level the turntable as the tower pivots in use. The tilt-compensating mechanism includes at least one support that is driveable up and down with respect to the tower. In the embodiment disclosed, the support is a carriage movable along an upright track that pivots with the tower.

First claim

The invention claimed is:

1. A turntable assembly for supporting personnel performing welding, inspection, coating and clamping operations on a pipe string in a pivotably-mounted J-lay tower of a pipelaying vessel, the assembly comprising:
an annular turntable supporting personnel within the J-lay tower and having an annular platform defining a central opening to receive the pipe string;
a base frame that supports the annular turntable to turn around the pipe string; and
a tilt-compensating mechanism for attachment to the tower, acting on the base frame to tilt the turntable relative to the tower to level the turntable as the tower pivots;
wherein the tilt-compensating mechanism comprises at least one carriage that movably attaches the tilt-compensating mechanism to the tower and that is driveable up and down with respect to the tower, the at least one carriage being movable along a track that is fixed to the tower and that pivots with the tower; and
wherein the base frame is pivotably connected to the at least one carriage by a member that is hinged with respect to the carriage about one pivot axis and that carries a pivot defining a second pivot axis so that the base frame is pivotable with respect to the at least one carriage about two mutually-orthogonal, generally horizontal pivot axes.

2. The turntable assembly of claim 1 , wherein the at least one carriage is driven in response to manual control or to signals from a control system that controls pivoting movement of the tower.

3. The turntable assembly of claim 1 , wherein the base frame is supported with respect to the tower entirely by one or more of the at least one carriage.

4. The turntable assembly of claim 1 wherein the at least one carriage comprises at least two carriages, wherein the turntable is levelled at least partially by differential elevation of the at least two carriages.

5. The turntable assembly of claim 1 , wherein the base frame pivots about one pivot axis in response to up-or-down movement of the at least one carriage and about the other pivot axis in response to an actuator acting between the base frame and the carriage.

6. The turntable assembly of claim 5 , wherein the actuator acts either in response to manual control or in response to signals from a control system that controls pivoting movement of the tower.

7. The turntable assembly of claim 1 , wherein the member is supported by a suspension frame that is fixed to the carriage.

8. The turntable assembly of claim 1 , further comprising a beam that is pivotably attached to the member at the pivot and that supports the base frame.

9. The turntable assembly of claim 1 comprising a floating joint between the base frame and the at least one carriage, the floating joint comprising at least one lateral support element that is laterally extensible and retractable with respect to the base frame.

10. The turntable assembly of claim 9 , wherein the lateral support element of the floating joint is received telescopically in a tubular member of the base frame.

11. The turntable assembly of claim 8 , comprising a floating joint between the base frame and the at least one carriage, the floating joint comprising at least one lateral support element that is laterally extensible and retractable with respect to the base frame, wherein the beam carries the lateral support element of the floating joint.

12. The turntable assembly of claim 1 , wherein turntable elevation is adjustable separately from tilt compensation by up-or-down movement of the at least one carriage.

13. The turntable assembly of claim 1 , wherein the turntable comprises a core about which cables or umbilicals are wound to provide services to welding apparatus acting on the pipe string.

14. A vessel having a pivotably-mounted J-lay tower, or a J-lay tower for such a vessel, comprising a turntable assembly for supporting personnel performing welding, inspection, coating and clamping operations on a pipe string in the J-lay tower, the assembly comprising:
an annular turntable supporting personnel within the J-lay tower and having an annular platform defining a central opening to receive the pipe string;
a base frame that supports the annular turntable to turn around the pipe string; and
a tilt-compensating mechanism for attachment to the tower, acting on the base frame to tilt the turntable relative to the tower to level the turntable as the tower pivots;
wherein the tilt-compensating mechanism comprises at least one carriage that movably attaches the tilt-compensating mechanism to the tower and that is driveable up and down with respect to the tower along an upright track that is fixed to the tower and that pivots with the tower; and
wherein the base frame is pivotably connected to the at least one carriage.

15. A method of levelling an annular turntable that supports personnel and turns around a pipe string when performing welding, inspection, coating, and clamping operations in a pivotably-mounted J-lay tower, the turntable supporting personnel being within the J-lay tower and having an annular platform defining a central opening to receive the pipe string, the method comprising supporting the turntable by one or more carriages that movably attach a tilt-compensating mechanism to the tower and driving the or each carriage up or down with respect to the tower along a track that is fixed to the tower and that pivots with the tower to tilt the turntable relative to the tower to provide compensation for the tilt of the tower.

16. A method of pipe-in-pipe welding involving the use of a turntable in a pivotably-mounted J-lay tower, the method comprising supporting the turntable by one or more supports and, when welding a joint to a pipeline end, driving the or each support up or down with respect to the tower to different weld elevations as required by the pipe-in-pipe arrangement and levelling the turntable according to the method of claim 15 .

Assignees

• Cruickshank John Duncan
• Subsea 7 Ltd

Inventors

• Cruickshank John Duncan

Classifications

• B63B35/03

  Pipe-laying vessels (laying pipes under water F16L1/12) · CPC title

• B23K37/0276

  for working on or in tubes (B23K37/0211 takes precedence) · CPC title

• F16L1/207

  Pipe handling apparatus · CPC title

• F16L1/235

  Apparatus for controlling the pipe during laying · CPC title

• F16L1/19 Primary

  the pipes being J-shaped · CPC title