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

摘要

The finished ring consists of an inner ring (2), outer ring (3) and, spaced at intervals between them, aerofoil section vanes (4) which direct steam onto the turbine blades at the desired angle. To produce the ring a ring (5) having a U-section lying on its side with the opening (7) in the steam flow path is first cut out of plate. 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. The vanes may be a press fit in the holes or secured by adhesive. ADVANTAGE - Rings of higher strength and quality can be produced more simply in shorter throughput time and at lower production cost.