Confirmation of hydrogen damage in boiler tubes by refracted shear waves
US5243862A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 1991 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Jun 4, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/048
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for distinguishing between hydrogen damage in the wall of a boiler tube, and surface damage on the inside surface of the tube, comprises a pair of transducers which are spaced on the outer surface of the tube and which apply a refracted shear ultrasonic wave through a chord of the tube with a beam angle that is calculated from the outside radius and wall thickness of the tube. The transducers are first applied to an undamaged tube and an instrument connected to the transducers is adjusted to 80% of full screen height. The same transducers are then, applied to a suspected boiler tube. Any attenuation of the initially high amplitude below 12 dB indicates hydrogen damage as opposed to inner surface damage which has been found to produce a far lower attenuation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.