The modern N- line tensioner design is used to ensure a pre-defined tension to the marine riser and to compensate any rig motions like heave, roll or pitch. The system consist of accumulator loaded, long stroke hydraulic cylinders, which are directly mounted between the drill rig structure on one side and the tension ring on the other side.
Because N- line tensioner cylinders are installed directly in the splash zone with partly submerged piston rods an excellent corrosion protection is necessary. The Ultraplate coating guarantees premium corrosion protection as well as high wear resistance for the continuously moving rods. Hunger DFE seal and guiding elements are used to provide long life properties. Other special features are an externally adjustable seal which can improve the reliability of the whole system, an absolute position measuring system, special ball joints allowing a tilt movement in any direction and the Nitrogen loaded accumulators with rupture disc and temperature safety valve.