Study of Defects in the Petrochemical Storage Tank Floor using the Magnetic Flux Leakage (MFL) Technique

In this work, the magnetic flux leakage (MFL) technique has been used for analyzing the defects in the floor of a petrochemical storage tank. Tank floors are more vulnerable to many damages because of the stored materials. The chemical reaction that occurs between the stored substances and the floor causes the floor to corrode easily. Mostly, tank floors are made up of ferromagnetic materials and to inspect these floors the MFL technique is preferred. Here, a robotic MFL system is designed to interrogate the defects through flux leakage, because it improves the health and safety inspection in hazardous working environments. This system has two major units namely the power and the detection unit. The robot’s displacement is controlled by the power unit and the detection unit is responsible for the defect analysis. Two types of defects such as grooves and holes were introduced in the low carbon steel plate. The plate is electro magnetized and for every movement of the robot, the respective magnetic flux is sensed by the Hall sensor. The acquired data are plotted with the help of Arduino connecting to the computer. Thus, by analyzing the plotted waveform graph, the defects were detected due to the leakage of magnetic flux at the defect region with good signal-to-noise ratio. And error percentage was calculated within 10% for the measured signal.