Distributed Buoyancy Modules

A distributed buoyancy module is a two-piece construction that is designed to attach to an umbilical or riser to reduce the submerged weight during installation.
The two modules are defined as follows;
1. Split buoyancy module
2. Axial Restraint Friction Clamp

Assemblies are produced in various sizes and lengths to suit the project specific uplift requirement.

The buoyancy module is produced as a split design in two identical halves. Each half incorporates internal cavities to enable it to be installed around the Axial Restraint Friction Clamp. The buoyancy modules are cast in an enclosed mould from polyurethane MDI foam with a density of 300kgs/m3. A 5mm thick outer reinforced polyurethane skin is sprayed onto the buoyancy to offer topside protection during installation and to ensure subsea visibility. The buoyancy elements are held in place using field proven subsea tensioning straps

The Axial Restraint Friction Clamps are a three-piece clamp manufactured from polyurethane 80 shore D. This is a high strength polymer, which provides excellent mechanical properties for long tern subsea applications.

All three-clamp sections are fitted with soft polyurethane liners. This increases the co-efficient of friction whilst providing a soft interface against the riser / umbilical and flexibility in that it can accommodate ovality and out of roundness tolerances. The retaining pins, and all fasteners are all manufactured from super-duplex UNS32760 to provide long-term corrosion resistance. The machining of the clamps is performed in house by CNC machines to provide the optimum machine finish and tolerances.

Specification:
• cable diameters: 50mm to 400mm
• uplift force: project specific
• materials: MDI foam and polyurethane

Features:
• easy installation
• field proven strapping system