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News from the Institute Branches – May 2018 

| South Wales Branch
Low-profile ultrasonic transducers: how low can you get?

Steve O'Brien reports


The South Wales Branch met for its March meeting at the Ty Crawshay Building at the Treforest Campus of the University of South Wales. Having arrived at the impressive university building we were greeted by our host, Dr Navartne, who took us to the lecture hall, where we joined approximately 40 students for the presentation.

This event was the University‘s ‘NDT Annual Lecture’, hosted By Dr Rukshan Navaratne, Lead Academic, School of Engineering, University of South Wales.

Once we were all comfortably seated, he introduced John Skidmore to the assembled audience and the presentation started. John began with an overview of the effectiveness or, perhaps more accurately, the limitations of the current methods for testing small bore ‘pipe-to-fitting’ welds, typically used in the petrochemical industry. He then moved on to a brief explanation of the access restrictions posed by the geometry and the difficulties encountered when using traditional in-service inspection methods. For example, radiography requires the pipes to be drained and large areas of the plant cordoned 
off.

Next, John gave us an overview of the LIMBOTOFD, a time-of-flight diffraction (TOFD) method ‘advanced inspection solution’ that uses a scanner and unique curved transducers, small enough to glide under bolt heads (hence ‘LIMBO’) to perform a more effective and reliable inspection.
The presentation continued with a comparison of radiographic testing (RT), phased array ultrasonic testing (PAUT) and TOFD on known defect samples to illustrate the effectiveness and limitations of each method. Finally, John took a few questions from Branch members and from some of the students, who were keen to get a better understanding of TOFD beyond what they had experienced in the classroom environment.

After the presentation, we moved next door where a practical demonstration of the system had been set up. This allowed both the Branch members and the students to have the chance to put the theory into practice – an opportunity that was enthusiastically accepted by both.

Many thanks to John for the very informative presentation and practical demonstration, and to Rukshan for hosting and providing an enjoyable and interesting visit.