In this research, the development of a Non-Destructive Test (NDT) system by a Magnetic Flux Leakage(MFL) method is presented.
The detection of a crack or defect of a gas pipe is very important in management of a gas pipe. The sensing equipment, so called PIG, is commonly used to detect defects of the underground gas pipe. The system is consisted of magnetic yoke, Hall sensors and gas pipe.
in the system, the magnetic field produced in permanent magnet is guided to the gas pipe by brush and magnetic yoke. The Hall sensors detect the leakage flux in the region of defects such as crack, corrosion, wrinkle, buckle and so on.
The defect signals in a MFL type NDT system mainly depend on the change of the magnetic leakage flux in the region of a defect. So, the optimum system was designed to maximize the magnetic leakage flux in that region and the results are compared with experimental measurements.