Linear Compensators are typical cylinder or gravity-based systems with multiple sheaves for wire or rope position and/or tension control. AXTech has over the years developed a comprehensive in-house library for compensator design and software, varying from shock absorbers and active heave compensators to umbilical tensioning systems.
By utilizing active and passive power sources such as hydraulic power units and nitrogen volumes, the design can accommodate for the different needs of the system. In some cases, even weights and gravity may provide a good solution for tension control.
AXTech compensator design and control system are all developed in-house by our experienced and skilled engineering teams in close cooperation with carefully selected hydraulic sub-suppliers
Our systems can be provided as free-standing inline systems based or fully integrated in structures such as a tower or a-frame. Capacity is according to client specification, but more than 1000t and 20m stroke has been delivered to different projects.
Active Heave Compensators (AHC) are designed for the safe landing to, and lift from the seabed during high seas, reducing the vertical movement to a minimum in sea conditions of up to and above Hs 5. The AHCs can also be used as one-impact shock absorbers simply by turning a switch in the control system.
Passive Heave Compensators (PHC) provides a simple and useful tensioning system, protecting the equipment from sudden impact and limiting the dynamic forces in the system. The accuracy is not the same as for the AHC, but in many applications sufficient and often considered a more robust system for long time operation than active systems.
AXTech Shock Absorbers are usually passive systems based on the same principle as the AHC, i.e. a hydraulic cylinder working against an accumulator and several gas tanks. In some cases, more accuracy may be needed, and active cylinders and/or HPUs may be introduced in parallel with the passive system.
Line Tension units are primarily used to prevent slack lines. An example may be keeping a subsea mining machines umbilical taught to ensure it is not entangled with the machine. The tension accuracy may not be high, but systems like this may work for years without stop, and maintenance and minimum effect on the umbilical or rope is very important.
All systems can be delivered with HPUs, Nitrogen Intensifiers and other relevant equipment.