Drive unit for pipeline pig comprises clamps which can slide along cable and are mounted on bellows attached to it, so that unit can be moved along pipe by unequal expansion of bellows

摘要

The drive unit for a pipeline pig comprises clamps (3) which can slide along a cable (2) and are mounted on a bellows (1) attached to it. The unit can be moved along the pipe (13) by unequal expansion of the bellows.