Why choose guided wave ultrasonic testing?
LRUT (Long range ultrasonic testing) or sometimes called as GWT (guided wave testing) is becoming commonplace today for pipeline inspection. This technology is used as excellent NDT for the screening tool. Guided wave ultrasonic inspection offer many advantages such as High productivity (kms per day), access required only at discrete locations, carried out with pipe on-line ( not require shutdown) and 100% coverage except for flanges, tees and other large features. This LRUT/GWT technology come as a solution for pipeline inspection problem like restricted access, many lines not suitable for in-line inspection (ILI / pigging inspection), regular UT and RT techniques are typically not cost-effective or typical UT and RT coverage 0.1%. After conduct LRUT/GWT screening and found some anomaly or “indication”, the inspector will dig the anomaly with other NDT tools such as UT scanning or UT Flaw detector.
How guided wave ultrasonic testing work?
The tools create Symmetric waves that transmitted along the pipe. The waves propagate along, not through, a pipeline. The wave is reflected from changes in the cross-section in a pipeline. The amplitude of the reflection depends on the total change in the pipe wall cross-section. The percentage cross-section loss is given by the reflection amplitude, but it could be equally distributed around the circumference (e.g. a shallow wall loss) or concentrated in a narrow portion of the pipe (e.g. a critical deep defect).
Standard UT uses high frequency and short wavelength. Standard UT sensitive to small defects at high frequencies and use as point measurement. Guided waves ultrasonic testing use low frequency and long wavelength. GWT / LRUT sensitive to “small” defects even at low frequencies and used as rapid screening.
Guided wave ultrasonic testing development and its customer
- 1990 D Alleyne/P Cawley Imperial College
- 1995 Industrial sponsored project: 1st Wavemaker prototype
- 1999 Guided Ultrasonics formed: Wavemaker SE16
- 2005 Wavemaker G3 with dynamic frequency
- 2007 Enhanced focussing rings and software
Companies which have bought Wavemaker or included it in their procedures include BP, Shell, PetroChina, Gazprom, Chevron, Petrobras, EON, Pemex, Conoco Phillips, Beijing Gas, Oxidental, Dow Chemicals etc. For more information about the product of Guided waves ultrasonic testing, please visit https://www.guided-ultrasonics.com/home/catalogue/.