Speed control system for a pipeline inspection vehicle

摘要

A pipeline inspection system in which a vehicle, which has sensors to detect flaws in the pipeline, is moveable within the pipeline by a fluid flowing in the pipeline, and wherein a speed control for the vehicle is provided by a braking device which imposes a continuous axial drag on the pipeline wall. This continuous axial drag is adjustable between upper and lower limits such that the summation of the variable drag characteristics of the pipeline and the imposed drag remains approximately constant and the vehicle will move at a speed substantially equal to the average flow velocity of the fluid in the pipeline.