Carousel for flexible product
A carousel for the storage of flexible product, and a method of loading flexible product thereon, wherein said carousel comprises an open drum mounted to rotate around a vertical axis, an elevatable floor, preferably internal to said drum and lifting means for lifting and lowering said elevatable floor. Said lifting means possibly being located between a base of said carousel and said elevatable floor. Said carousel may be of the type designed for location under deck on a marine pipelaying vessel, said flexible product being flexible conduit for the transport of hydrocarbons.
1. A carousel for mounting in a marine pipelaying ship for the storage of flexible pipeline for subsea transport of hydrocarbons, wherein said carousel comprises:
an open drum mounted to rotate around a vertical axis, an elevatable floor and a lifting mechanism for lifting and lowering said elevatable floor, said carousel being under deck on said marine pipelaying ship; and
a controller for controlling said lifting mechanism, said controller being operable to lower the floor of the carousel as pipeline is loaded thereto from above in such a way as to maintain a pipeline entry angle within predetermined limits.
2. A carousel as claimed in claim 1 operable to be used in a horizontal configuration, the carousel further comprising a base, an outer cylindrical wall and a central hub.
3. A carousel as claimed in claim 2 wherein said elevatable floor is a floor other than said base and said lifting mechanism is located between said base and said elevatable floor.
4. A carousel as claimed in claim 1 wherein said lifting mechanism comprises airbags, such that the level of the floor is dependent on the pressure inside said airbags.
5. A carousel as claimed in claim 1 wherein said controller is further operable to maintain the pipeline entry angle substantially constant.
6. A method of loading flexible pipeline for subsea transport of hydrocarbons onto a horizontal carousel mounted in a marine pipelaying ship, said method comprising:
raising a floor of the carousel to a predetermined position;
lowering the flexible pipeline onto said floor, from above, while said carousel is turning; and
maintaining a pipeline entry angle within predetermined limits, by lowering the floor of the carousel as the pipeline is loaded thereon.
7. A method as claimed in claim 6 wherein said predetermined position is the floor's uppermost position.
8. A method as claimed in claim 6 wherein said floor is lowered stepwise during loading.
9. A method as claimed in claim 6 wherein said floor is lowered substantially continuously during loading.
10. A method as claimed in claim 6 wherein said pipeline entry angle is kept substantially constant during loading.
11. A method as claimed in claim 6 , wherein said carousel is designed for location under deck on the marine pipelaying vessel.
12. A marine pipelaying ship comprising a carousel for the storage of flexible pipeline for subsea transport of hydrocarbons, said carousel being under deck on said marine pipelaying ship, wherein said carousel comprises an open drum mounted to rotate around a vertical axis, an elevatable floor internal to said drum and a lifting mechanism for lifting and lowering said elevatable floor, said lifting mechanism being located between a base of said carousel and said elevatable floor.
13. A marine pipelaying ship as claimed in claim 12 wherein said lifting mechanism comprises airbags, the level of the floor being dependent on the pressure inside said airbags.
14. A marine pipelaying ship as claimed in claim 12 wherein the carousel comprises a controller for controlling said lifting mechanism, said controller being operable to lower the floor of the carousel as product is loaded thereto in such a way as to maintain a pipeline entry angle substantially constant.