Peter Claessens, manager customer support & supply chain, said: “The FLNG vessel plays a crucial role in the high-profile offshore venture our customer was supporting. Any issue with the ship’s stability could disrupt the entire project, creating not only safety concerns, but a considerable loss of time and money for all involved.”
Eaton needed to supply a bespoke solution for the unusual mooring system compensating for the motion of waves, where the XL cylinders were in an atypical horizontal orientation.
Additionally, Eaton’s solution needed to withstand brutal conditions. Explains Claessens: “The challenge wasn’t only continuous exposure to saltwater and sea spray, but to sand blowing over from the Sahara desert in high winds. With project operations expected to run for up to three decades, Eaton’s solution not only had to perform, it had to be incredibly resilient.”
Design and manufacturing work took place at Eaton’s Eindhoven facility in the Netherlands, which boasts a team of dedicated project and application engineers, skilled assembly technicians and machining operators, as well as a state-of-the-art test facility.
“Our engineers collaborated closely with the customer for many weeks to develop a bespoke solution and, as always, we strived to make working together as quick and easy as possible,” states Claessens.
For instance, Eatonite laser cladding, Eaton’s proprietary cylinder rod coating, is said to offer superior corrosion resistance in saltwater operations following 10 years of proven use in the field with no reported failures.
“Eatonite is a very dense coating that allows no access to the base material, which is the usual cause of corrosion and coating failures,” said Alpesh Shah, global product manager - cylinders. “That’s a critical issue to avoid because corrosion doesn’t just impair cylinder performance; hydraulic fluid can also leak into the sea creating environmental problems.”
To create the coating, a laser beam spot impinges the piston rod surface, producing a shallow molten pool. Following the injection of Eatonite powder, the pool solidifies as the piston rod cools, leaving cascading weld beads. The rod is then turned and polished to the final surface parameters. The coating can be repaired in the field, as well.
Eaton also integrated a stroke measurement system, further enhancing the performance and safety factor of the mooring tensioners. The system enables the customer to know the position of the piston in the cylinder and accumulator at any moment. This capability also allows the early identification of any accumulator leaks, making it possible to deal with issues promptly. Without such a system, the first sign of a problem would be performance loss, or even sudden failure.
With just a 10-month lead-time, Eaton’s Eindhoven facility designed and delivered 12 mooring tensioner XL cylinders in carbon steel with built-in accumulators. Featuring a 600 mm diameter and 4,500 mm stroke length, these hefty hydraulic cylinders have a design pressure of 230 bar (3335 psi). Each one is also equipped with high-grade stainless-steel piping and manifold blocks.
Eaton now stands ready to provide the customer with long-term support for repairs, spares, servicing and upgrades as required in the future.