Steampath and process of retrofitting a nozzle thereof

Abstract

A process for replacing a multi-piece steampath in a nozzle box (12) where, initially, the steampath (22) is secured between upper (24) and lower (26) ring components by means of axially accessible, arcuate welds (36, 38) includes the steps of: a) axially machining the arcuate welds (36, 38) so as to permit removal of the steampath (22) in a direction axially away from the nozzle box; b) further machining a forward portion of the lower ring component to provide a substantially vertical weld surface; and c) securing a one-piece steampath (222) in place by an axially accessible upper weld (236) and a radially accessible lower weld (238). A nozzle box (212) for a steam turbine includes a torus portion 218 and a bridge ring portion (220), the bridge ring portion including radially inner and outer bridge rings (226, 224) connected by a plurality of bridge elements (234); a one-piece steampath (222) secured between the radially inner and outer bridge rings (226,224), the steampath (222) having integral upper and lower bands (232, 230) connected by integral steampath partitions (234), the steampath being secured to the upper ring (224) by an axially accessible weld (236) and to the lower bridge ring (226) by a radially accessible weld (238).

Dependencies are inferred from the claim text.