Manual crawler for internal scanning of large diameter pipes with eddy current array

MacKay, Philippe; Eddyfi; Canada

MacKay, P.; Eddyfi; Canada
Raude, A.; Eddyfi; Canada

ID: ECNDT-0119-2018
Session: Eddy Current-Techniques 2
Room: H2
Date: 2018-06-14
Time: 14:10 - 14:30

Internal surface inspection of large diameter stainless steel pipes, such as chemical loop reactors or pipeline cladding, can be a very complicated task due to the enclosed space and large surface to inspect. Smaller diameters can be inspected with oversized Eddy Current Testing (ECT) tubing probes and provide adequate results. While large diameters can be addressed by human operators performing traditional NDT methods from the inside, a certain range – typically between 200 and 600mm in diameter – remains challenging. Also, traditional methods such as penetrant testing (PT) and magnetic particle testing (MT) tend to be very operator-dependent, time-consuming, provide no data retention or imaging capabilities and require extensive surface preparation.
Eddy Current Array (ECA) probes have a long history of proven efficiency and reliability for surface breaking defects. Surface ECA probes can cover large areas in a very short time, and require minimal surface preparation. The main challenge when deploying ECA probes is to make sure the probe contact is adequate throughout the scan.
This paper describes the application of a flexible ECA probe mounted on a manual pipe crawler which can be easily adjusted to address a wide range of diameters. The result is a lightweight probe and crawler system which is easy do deploy, offers state-of-the-art data visualisation and archiving, and can cover large pipe ID in a very short time. One version of the system was designed with a 200 mm coverage designed to fit in 350 mm (14 inches) to 560 mm (22 inches) diameter pipes. A 6.7 m (22 foot) long pipe with a diameter of 500 mm (20 inches) was inspected in 8 passes in less than 30 minutes, while this part could not be inspected on site before.