An innovative approach towards defect detection and localization in gas pipelines using integrated in-line inspection methods

Abstract The current study presents a novel and high-sensitivity in-line inspection (ILI) method for gas pipelines. The proposed method is based on integrated ILI methods, optical sensor and bimorph sensor. The uniqueness of the proposed method lies in; (1) combining two advanced methods for more accurate and sensitive outcome, (2) real-time inspection of target pipeline, (3) specifically designed sensor array to estimate and locate defects in three dimensions and (4) low power consumption and economic viability. The theoretical framework for the relationship between the sensor outputs and the presence of defect as well as the design of the sensor housing module are also developed and presented. Laboratory tests are conducted on various types of defects to illustrate the robustness and sensitivity of the method. Additionally, the conventional magnetic flux leakage (MFL) method is adopted to verify the effectiveness of the proposed method. Furthermore, for the of real-world application purposes, a smart pipeline inspection gauge (smart PIG) with integrated different sensor arrays are developed for the field testing of gas pipeline networks. The two-dimensional (2-D) image produced by the sensor array is presented to visualize the inner surface of the pipeline and to enable accurate identification of a bolted pipe joints. A speed control system is also developed and designed to eliminate errors caused by speed spikes and to maintain the speed of the smart PIG within the desired range. An analysis of the chatter vibration signal of the smart PIG running in a gas pipeline network is presented. The current research work provides a solid base towards a step change from a pilot study to the real-time, real-world application of a novel inspection method for pipelines.