Controlled buoyancy underwater riser system - has the primary riser surrounded by a jacket foaming buoyancy chambers

摘要

A pressure fluid supply is connected to the buoyancy chambers via valve which controls the amount of water displaced from the chamber by the pressure fluid. Advantageously, the valve means for each chamber also includes remotely controlled means by which the amount of buoyancy provided by the chamber can be varied at will, e.g. from a positive buoyancy to a buoyancy less than the operating weight of the portion of the riser system with which that chamber is associated. Pref. the lengths of jacket pipe are interconnected into a continuous structural unit by connectors each having a female connectors secured to the upper end of the lower length of jacket pipe and a male member secured to the lower end of the upper length of jacket pipe, the female member having an annular bulk-head which closes the space between the jacket and primary riser pipe and on which the valve means is mounted.