Detecting Technology for External Anticorrosive Coating Defects of Buried Pipelines

The external anticorrosive coating is the shelter for preventing buried steel pipelines from corrosive damage. Many pipelines face severe corrosive problems because of the performance decrease of the coating, especially during long-term services. This situation usually causes safety accidents. Periodic inspection to the coating is an important way to ensure running safety. Aimed at the detecting technology, the methods for locating the pipelines and the means of on-line defects detecting with no excavation for the coating were studied and introduced. The ways for direction detecting, depth measuring and location coordinates detecting were pointed out. The basic principles of data analysis were also outlined. The various influences coming from external environment factors to the detecting results were analyzed.