The C1 Wedge Connection™ is expected to be fully maintenance free. This is the result of the following factors:
1. Removal of potential sources for preload loss.
One of the main sources for preload loss in traditional bolted connections are settlements in the threads. In the C1 Wedge Connection™ this problem is not experienced for several reasons:
Where a traditional bolted L-flange requires one tenth of a rotation to reach full preload the preload in the C1 Wedge Connection™ is build up in roughly 4 full rotations of the bolt.
Meanwhile traditional bolted L-flanges are pretensioned up to 90% of yield whereas the C1 Wedge Connection™ typically is tightened up to 70% of yield of the bolt.
Thirdly the preloaded load path in a properly preloaded bolted L-flange results in a load fluctuation experienced by the bolt of roughly 20%. In the C1 Wedge Connection™ the preloaded load path experiences only 5-10% of the externally applied load.
Due to the inclination angle of the wedges the bolt that pulls the wedges together experiences less than 0.1% of the externally applied load.
2. Unsensitivity to preload loss
On top of the mitigation of preload loss the C1 Wedge Connection™ is also very unsensitive to preload loss. The fatigue critical detail in the connection is essentially the stress concentration around the holes in the connection which is not affected by the preload level. Since the stress fluctuations are occurring in base material the fatigue resistance is much higher than the fatigue resistance in bolted connections.
3. High quality installation possibility.
During installation the interface between both tubulars is visible. This allows for a direct confirmation that the flatness tolerances are met and that there is a direct and effective transfer of preload. The initial installation of the C1 Wedge Connection™ can be performed with just a few percent of preload. Inspection of the interface can be performed out of the critical time-path. After that, the connection is tightened for life.