Service pipe coupling within a gas turbine nozzle guide vane

摘要

vanes 20 are generally hollow with a passage 23 through which service pipes 24 extend. These service pipes 24 must be connected such that they can allow for thermal expansion and contraction but also anti rotation features are needed in order to prevent damage when a supply coupling is connected through a pipe end 25. This anti-rotation feature is generally provided between a top hat 26 and a pipe end 25 through flanges 30, 31. In order to allow reduced spacing between the top of the vane 20 and a casing the flanges 30, 31 are arranged to allow at least recessing of a first flange 30 into a passage opening profile 27 whereby those flanges 30 inter-engage with second flanges 31 at a surface interface 33 to prevent rotation.