3D printed bio-inspired sealing disc of pipeline inspection gauges (PIGs) in small diameter pipeline

Abstract

PIGs (pipeline inspection gauges) have been the main equipment for pigging, inner inspecting operations in oil and gas pipelines. Due to the insurmountable shortcomings of conventional sealing discs, it is impossible to actively control the PIG when it is running on the pipeline, which leads to no way when the PIG is stuck. In this study, a new type of bio-inspired sealing disc was designed in combination with the webbed foot structure of animals (e.g., bird, frog, duck), soft robot technology and the conventional sealing disc, adding a new way to the mechanical pigging method. And the 3D printing technology was used to print the sample of the bio-inspired sealing disc, taking into account the new direction of manufacturing the PIG. Then, effects of the interference (δ), clamping rate (ζ), webbed foot thickness (tw) and the number of webbed foot (N) of the bio-inspired sealing disc on the contact force and stress were studied using MSC Marc 2016 when the PIG was in pipe. The simulation results show that the contact force and stress on the bio-inspired sealing disc are not uniform, showing a great difference in the uniform contact force and stress on the conventional sealing disc. The effect of interference and clamping rate on the maximum contact force, stress on the bio-inspired sealing disc and the influence on the conventional sealing disc are basically the same, but the impact on the minimum stress and contact force is different. The thickness of the webbed foot has the greatest influence on the contact force, stress on the bio-inspired sealing disc, and the number of the foot has the least influence.