Load Limiting Bails
The TENSA Load Limiting Bails (LLB) work as an independent safety mechanism when the rig’s heave compensator fails. The LLB is normally fully retracted and will not affect the normal functionality of the compensator. It will automatically extend when its preload tension is exceeded.
The TENSA LLB evolved from our Dynamic Load Reducer product range. These use similar technology that has been proven from extensive offshore operational experience. A pair of LLB200-600 bails is rated for a SWL of 200t (ie SWL 100t per bail). During normal operation, the LLB is maintained fully retracted by pressurized nitrogen. The LLB starts extending only when the load is higher than 100t on a bail. By adjusting the precharge pressure the initial load at which the bail arm extends is adjustable.
The LLB load is limited to 125 tonnes. It will initially extend by 1.5m and the load will rise from 100t to 125t. It can be stroked further up to the full stroke of 6m but the load will remain constant at approximately125t. If the extended length is below 1.5m, the LLB will retract and remain at its initial load setting after the overload scenario has passed. When further extension is utilized a small amount of the internal nitrogen precharge is relieved and the preload will be slightly less.
The TENSA LLB200-600 has the following features:
- Automatically returns to retracted position once the overload condition has passed.
- No replacement parts are required once activation has occurred. (eg shear pins)
- No connecting hoses. Each bail arm is a standalone system.
- Robust and easy to handle. The unit can be laid directly on the deck in any orientation.
- Activation load can easily be adjusted by changing the initial pre-charge pressure
- Direct replacement of the existing rig conventional elevator links.
- Does not affect the normal operation of the existing compensator.
- Bail arm ends are replaceable and alternative end attachments can be provided (e.g. lifting padeyes)