Riser section for use in deep sea oil drilling has auxiliary conduit fixings that allow rotation relative to main pipe and perpendicular to its axis

摘要

A riser section comprises a main pipe (2) and one or more auxiliary conduits (3) parallel to the main pipe and connected to it by fixings (7, 8). The fixings allow lengthwise efforts to be transmitted from the auxiliary conduits to the main pipe and at least one allows a rotational movement by the conduit relative to the main pipe about an axis perpendicular to the axis (4) of the main pipe. At least one of the auxiliary pipe fixings is in the form of a ball joint with a fork fixed to the main pipe and fitted with bearings for coaxial shafts on the auxiliary conduit. The main pipe is made from steel reinforced by composition strips.