US Patent 6880195 Pipe cleaning device

A vehicle (210) for travel though a fluid-filled pipe (12) is disclosed, capable of using power derived from the fluid flow to drive the vehicle (210). Certain embodiments have drive means capable of variable pitch in order to adjust the speed and direction of the vehicle in the pipe. Certain embodiments have drive means comprising a helical arm that can vary in pitch and diameter to accommodate different sizes of pipe and/or different rates of travel along the pipe.