Non-rotating buoyancy modules for sub-sea conduits

A protective buoyancy module assembly for attachment to a sub-sea conduit to reduce the conduit's effective weight in deep-water applications, the buoyancy module assembly comprising:

• a buoyant tubular sleeve adapted for positioning around a rotatable sub-sea conduit, the sleeve made from a non-porous, substantially rigid molded polymeric resinous matrix forming a generally cylindrical body of the tubular sleeve adapted to encompass the outer surface of the sub-sea conduit;
• a dispersion of finely divided elements having a closed structure with a hollow interior and a density less than water embedded in and dispersed throughout the cross section of the resinous matrix to increase its buoyancy;
• and a non-porous abrasion-resistant resinous outer coating formed as a thin jacket bonded to and encapsulating the surface of the tubular sleeve, the sleeve having an inside diameter adapted to encompass the conduit in a non-rotating configuration;
• and
• at least one stop collar assembly adapted for attachment to the conduit adjacent the sleeve for positioning the sleeve along the conduit, the stop collar assembly comprising an inner collar adapted for rigid attachment to an outside diameter of the conduit, the inner collar having an outside diameter less than the outside diameter of the sleeve, and an outer collar formed as a shell encompassing the outside diameter of the inner collar, the outer shell adapted for attachment to the inner collar, the outer shell having a maximum outside diameter less than the outside diameter of the sleeve, the inner collar positioned in a recessed interior region of the outer shell that allows relative rotation between the inner collar and the outer shell during use.