The Vertebrae Bend Restrictor (VBR) is designed to prevent damage to the cable it protects. It offsets the actionof applied loads which could kink or buckle the internal conduits of an umbilical, cable, flexible riser pipe or MUX line.
The characteristics of the VBR allow the umbilical to freely flex in any direction,limiting it at the Locking Bend Radius (LBR). At that point the segments of the VBR will lock on each other increasing the effective stiffness of the cable it protects to withstand specified loads applied to the device without violating the specified minimum bend radius (MBR). The VBR will accommodate lines 0.5inch (13 mm) to 16 inches (406 mm) in diameter and is made from either polyurethane or steel depending on the need.
VBR Spec Sheet VBR Inquiry Sheet
The Steel Vertebrae Bend Restrictor (SVBR) is designed to prevent damage to the umbilical control line that it supports at higher loads than its polyurethane counterpart. SVBR assemblies share the same characteristics as polyurethane VBR assemblies in that they protect the controlline to a customer specified Minimum Bending Radius (MBR). Due to the material properties of steel in comparison to polyurethane, SVBR assemblies do not exhibit a large differencebetween the Locking Bend Radius and the MBR under loading.
The SVBR Assemblies are comprised of male and female type segments that fit into each other. The male segment pair is locked inside the adjacent female segment pairs, thereby reducing the number of fasteners required to complete the assembly. SVBR assemblies are equipped with polyurethane stress wafers that work to evenly distribute the stress during loading.
(VBR Spec Sheet) (VBR Inquiry Sheet)
ABCO custom designs VBRs to customers’ specifications. Static and dynamic loads are specified by the customer or calculated by our engineers using catenary tension, angle from the umbilical termination assembly (UTA) at which the tension acts, and the required minimum bending radius. Depending on the required load and product line, the LBR is specified to be anywhere from 10-100% larger than the MBR to account for deflection under load. The urethane used provides excellent elasticity for repeatable loading and catastrophic failure prevention. ABCO has designed urethane VBRs for serviceup to 8000 feet of water depth.
