Gas pipes buried underground might be damaged by aging. Therefore, inspection is needed for safety. We have been developing a pneumatically driven robot to insert from a meter gas cock without excavation and to observe the inside conditions by locomoting in service pipes. In this paper, the practical performance of the robot was moreover enhanced, with development of a highly durable thrust module and improvement of the robustness for the bending module. By using natural rubber tubes and bellows made of polyethylene terephthalate (PET), the trust module was capable of thrusting operation for more than 5,300 times. Also, we introduced a new sealing method to prevent the air leakage from the thrust module. Furthermore, we improved the robustness for the bending module by reinforcing the connection between components and adding a cover to smooth the surface. According to a retrieval experiment from a 7[m] service line with a meter gas cock, it was confirmed that the robot could be retrieved up to 11 times (9 of which are undamaged).
