More good news for Allen Gears Services personnel - and for their reputation in the aftermarket sector - is the recent delivery of a major reverse-engineering programme in the shape of a new rotor set for a formerly troublesome gearbox on a Statoil offshore production platform.
The Heidrun platform, operated by StatoilHydro ASA, is situated in the Norwegian Sea. It has design production capacity of 220,000 barrels oil / day and 5 million Sm3 gas / day. The production began in 1995.
On board the platform are 3 x RB211 gas turbine driven generators, each containing a speed reducing GEC parallel shaft gearbox. The generators provide the complete power requirements for the platform.
One of the non-Allen gearboxes on board the platform, suffered from particularly high vibration and the operator decided to call in Allen Gears Services to fix the problem.
Allen Gears went to site, and after in-depth technical analysis and troubleshooting, it was discovered that the gearwheel had moved both axially and circumferentially on its shaft. The parts were returned to Allen Gears where more investigation took place and the gearwheel assembly was deemed not fit for further operation.
New parts were manufactured using reverse engineering, the new design included a review of the gearwheel shaft interference and modification of the quill shaft / hub assembly, whilst implementing the use of AG standard materials within the new design, but keeping the interface detail and space envelope as per the original.
One unit is now back in action, and key replacement components for the remaining two are being manufactured at Pershore.
"We had to ensure we designed and built the replacement components to match the precise tooth profile of the gearbox," says Francis Moss. "The first unit is now back in service and running smoothly. It's an excellent example of how thoroughly we can solve the sort of technical problems that faced this operator."