| 摘要 |
The umbilical has at least one longitudinal internal element for carrying fluids, electrical power or signals, or loads and a sheath 3. The sheath is formed by extrusion. So as to achieve a particular weight to length ratio for the umbilical (or specific gravity or weight to diameter ratio) the sheath is made of a polymer composite comprising a high density filler, the polymer composite having a density in the range 3 to 11 g/cm3. The polymer of the composite may comprise HDPE, PE, PP, PU, PA or PBT. The high density filler is preferably metal-based, the preferred metals being chromium, nickel, copper, copper oxide, steel, iron, iron oxide, barium sulphate, tungsten, molybdenum, and has a density of more than 4g/cm3. The umbilical is said to be more seabed stable with a typical specific gravity in the range 1.5 to 3, i.e. the umbilical is 1-5 to 3 times heavier than the displaced water. |
