One of the exhibitors at the CTOTF trade show, First Independent Rotor Service of Texas (FIRST), will demonstrate a unique procedure to remove and replace GE-type compressor blades inside the first and last rows without unstacking the rotor. Procedure can be accomplished onsite with the rotor in the casing, or in a repair shop.
Recall that compressor rotor blades for GE gas turbines are installed individually via dovetail slots in the compressor wheels. They are held in place axially by spacers on adjacent sides of the blades and locked into position with aggressive staking on the forward and aft sides of the wheels.
Until recently, the only blades that could be removed with the rotor in place were those in the first and last rows of the compressor section. Damage to any airfoils in rows between the first and last conducive to imminent failure required unstacking of the rotor to remove/replace them. This is an expensive and time-consuming task, especially when only one or two blades are affected.
The procedure developed by FIRST and its partners removes the damaged blade and the adjacent positioning spacers. A new blade and spacers are installed and secured using FIRST’s patented locking feature. Total time to remove and install one blade and its spacers is about eight hours. The technique generally is not recommended today if more than a few blades must be replaced.