Fixed equipment reliability is paramount in the power generation and petrochemical industries where heat exchangers are used to heat and cool various fluids across a wide spectrum of environments.
The tubes in heat exchangers made of materials including austenitic stainless steel and Inconel are plagued by circumferential cracking in the vicinity of the tube sheet, with these cracks regularly being induced by the localized stress created during the tube-to-tube sheet rolling process.
Conventional, single-coil eddy current testing (ECT) is not able to reliably detect cracks. Circumferential cracking is very difficult to detect and characterize with standard eddy current bobbin probes, currently the norm in the industry to inspect tubes.
We at ITCL inspect non-ferromagnetic heat exchanger tubing using Eddy Current Array (ECA), utilising advanced analysis software for graphical display (C-scan), record keeping, and reporting.
The DefHi™ tubing probe leverages Eddy Current Array (ECA) technology to accurately detect, size, and characterize circumferential cracking defects, differentiating them from other unwanted signals, such as those from the tube sheet and roll transition.
ECA technology uses several individual coils, grouped together into one probe. The coils are excited in sequence to eliminate interference from mutual inductance (something referred to as multiplexing).
In doing this, coils work together to completely sweep the interior surface of each tube.
Further benefits of ECA include:
Eddy current array technology greatly improves the speed and quality of results in this challenging application.
Contact a member of the ITCL team on 0151 356 7118 for more information.