Steam turbine flow guide ring production method - commences with U=section ring which has vanes pressed into EDM produced flange holes and web bored out to create flow passage

摘要

The flow guide ring may form part of a nozzle or an interstage steam flow ring. The finished ring consists an inner ring (2), outer ring (3) and spaced at intervals between them, aerofoil section vanes (4) which direct steam onto the turbine rotor blades at the desired angle. In its initial form the ring or ring segment is cut out of plate and has a U-section (5) lying on its side with the opening (7) in the steam flow path. Profiled holes for securing the vanes (4) are produced in the flanges (52,53) by EDM using a wire electrode machine with automatic cycle control. ADVANTAGE - Ring of higher strength and quality can be produced more simply in shorter throughput time.