Pulsed Magnetic Flux Leakage (PMFL) System for Pipeline Inspection: Detection and characterisation of defects in ferromagnetic pipes

摘要

This paper presents the setup of a prototype pulsed magnetic flux leakage (PMFL) system for pipeline inspection with magnetic field sensor array/magnetic field camera, and shows the capabilities of PMFL method of non-destructive testing (NDT) in defect localisation and characterisation. In PMFL, a 1Hz pulsed magnetic field is applied to the pipe wall using an electromagnet. Magnetic field sensors and a data acquisition unit are used to measure and store the PMFL field at the surface of the pipe wall for processing. The results show that the PMFL method of NDT has the advantage over traditional MFL methods, with respect to accuracy in defect sizing and the capability to discriminate between external (surface/nearside) and internal (subsurface/far-side) defects.