Frarendi Reminds the Gas Turbine Industry of the Importance of Proper Maintenance and Repair of EDM Cooling Holes in First Stage Nozzles
05 December 2007 11:12
With Fall maintenance schedules in full swing, Frarendi, a combustion service hardware innovator, reminds the land gas turbine industry about the importance of precision Electrical Discharge Machining (EDM) cooling holes in the proper maintenance and repair of first stage nozzles.
As the land-based gas turbine industry has evolved, repair and maintenance of key nozzle components have become highly complex processes built on precision engineering. One of the integral advances in technology is the addition of EDM cooling holes that allow gas turbines to run at higher temperatures with increased efficiency levels.
These holes are designed to cool the exterior surfaces, protecting the nozzle from high combustion heat while using a minimum amount of air to maintain efficiency.
"To the untrained eye, they just look like small holes," said Kevin Davis, president of Frarendi. "Gas rp/4/turbines require an extreme level of precision so the cooling holes have to be drilled to exact specifications, size and position. If they aren’t, you compromise the efficiency of the turbine and jeopardize the lifespan of the entire nozzle."
Frarendi's replacement coupons for eroded or damaged first-stage nozzles are made from the same FSX-414 metallurgical alloy and include the same precision EDM holes as the original parts. Each coupon is customized to fit a variety of trailing edge nozzle configurations for: Frame 3; Frame 5; Frame 6B; Frame 7B; Frame 7E; Frame 7F/7FA; and Frame 9E. They can also be customized with upgraded or modified cooling holes on both the trailing edge and the pressure side for special applications.
Nozzles become damaged and fail due to constant erosion from higher heat and other factors including: structural fatigue due to extended operating periods; using fuels with high levels of impurities; thermal forces and inadequate cooling; mechanical failures; hot corrosion; and damage caused by foreign objects. Repair shops worldwide have struggled to recreate these precision holes on eroded or damaged first stage nozzles. Frarendi's coupons, with pre-drilled EDM cooling holes, offer a much needed option.
For more information on this company:
Frarendi - Replacement Trailing Edge Coupons
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