Development of MFL system for in-pipe robot for unpiggable natural gas pipelines

This paper introduces a MFL system developed by a research project, which has been being conducted by KOGAS and initiated in 2011, to develop ILI (In-Line Ispection) Robot named “PIBOT” for the inspection of 16” to 14” unpiggable natural gas pipelines. All elements and functions in the proposed MFL (Magnetic Flux Leakage) system were designed to minimize friction between magnetizer and pipe wall and maximize defect detectability. To enhance driving performance and the ability of obstacle-negotiation, shunting system that can control direction of magnetic flux was developed. The performance of proposed MFL system was verified in the UPSF (Unpiggable Pipeline Simulation Facility) constructed to undertake several kinds of performance test about defect detectability, driving efficient and pressure resistance ability.