Patent ID: 9557210
Date: 2017-01-31
CPC Classifications: G01H

Claim:
1. A method for non-intrusive real time on-line detection of incipient crack of one or more blades in an operating steam or gas turbine for generating early warning of blade crack and its early replacement, the method comprising: A) placing sensor means non-intrusively on outer casing of said operating turbine to sense the blade vibration and generate blade vibration signals including raw vibration data amplitude versus time; B) obtaining real time turbine process parameter data from control panel of said operating turbine; C) acquiring said raw vibration data amplitude versus time and said turbine process parameter data in a data acquisition and analysis unit; D) transforming said raw vibration data amplitude versus time to frequency domain amplitude versus frequency spectrum including amplitude and frequency of blade passing frequency (BPF) in said data acquisition and analysis unit; E) carrying out correlation analysis in said data acquisition and analysis unit of the said amplitude versus frequency spectrum including amplitude and frequency of blade passing frequency (BPF) in relation to said turbine process parameter data for detection of presence of distinguishing features in pattern of vibrations of healthy blades and the ones with incipient cracks based on variation in said amplitude and frequency of BPF of said healthy blades and the ones with incipient cracks in any stage of different stages of turbine rotor by