Some compressor failures have been attributed to “lock-up” of the stator vanes. The vane roots are designed to rock slightly at their roots when moved with your hand. Rust and debris can inhibit this movement. An immobile vane changes the stress profile on the vane which can cause cracking and potential failure. Mechanics should check for proper movement at each inspection.
Removing locked-up stator vanes has been a challenge for service providers. The OEM has come up with material upgrades to address the corrosion problems in these areas. The compressor upgrades are designed to reduce the potential for compressor failures and lock-up of the stator vanes. Some providers use destructive methods to cut out the vanes, potentially damaging the compressor casing. The OEM recommends the use of their (expensive) special tooling to reduce and hopefully prevent casing damage. An alternate method that TGM®has used very successfully is a process of heating and quenching. Heating the locked-up stator vane segments with a torch and quickly quenching the vane with cold water will typically free the vane segment for removal without damaging the casing. The process of heating and quenching (applied by an experienced team) can save time and money while reducing and hopefully eliminating damage to the compressor casing. TGM® can provide its expertise in removing stubborn stator vane segments and, if needed, quickly replace damaged stator vanes to get the customer back on line as soon as possible.
TGM®‘s experienced combustion turbine Technical Directors and crews often delight customers by providing innovative methods that can efficiently and permanently solve issues and get the customer back on line to make power. Early detection of shim migration and stator vane problems can be performed by TGM®through borescope inspections and eddy current NDE.
TGM®‘s comprehensive borescope diagnostics can provide recommendations and solutions to address many other compressor issues. Contact Us to find out how we can help.