A pyrometer mount for a closed-circuit thermal medium cooled gas turbine

摘要

A steam-cooled second-stage nozzle segment has (10) an outer band (18) and an outer cover (22) defining a plenum (24) therebetween for receiving cooling steam for flow through the nozzles to the inner band and cover therefor and return flow through the nozzles. To measure the temperature of the buckets (15) of the stage forwardly of the nozzle stage, a pyrometer boss (46) is electron beam-welded (43) in an opening through the outer band (18) and TIG-welded (51) to the outer cover plate (22). By machining a hole through the boss and seating a linearly extending tube (58) in the boss, a line of sight between a pyrometer (P) mounted on the turbine frame and the buckets is provided whereby the temperature of the buckets can be ascertained. The welding of the boss to the outer band and outer cover enables steam flow through the plenum without leakage, while providing a line of sight through the outer cover and outer band to measure bucket temperature. <IMAGE>