Turbine blade vibration detection apparatus

Claim 1

Vibration detection apparatus for detecting vibration of turbine blades in a turbine system having a plurality of adjacent turbine blade rows, rotatable about a central axis, comprising: (a) a plurality of radar sensors mounted on said turbine system; (b) each said radar sensor being operable to transmit a relatively narrow beam radar signal toward a predetermined blade row and to receive a reflected radar signal therefrom to derive an output radar signal indicative of relative blade movement toward and/or away from said radar sensor; (c) means coupled to said turbine system to provide an output reference signal for each X degrees of rotation of said blade rows about said central axis relative to a reference position, where X≦360°; (d) means responsive to said output reference signals for providing, for each blade row having one or more said radar sensors, a running count indicative of the number of turbine blades which have traversed said reference position; (e) first gating means for gating said running counts; (f) second gating means for gating said radar output signals; (g) signal processing means operable to provide enabling signals, at predetermined times, to said first and second gating means and being operably connected to receive said signals so gated; and (h) said signal processing means being further operable to analyze said gated radar output signals to provide an indication signal if said analyzed signal is out of predetermined limits.