Apparatus for movement along an underground passage and method using same

摘要

An apparatus adapted for movement through a passage formed in the ground includes an elongate element and means for positioning a shroud around at least part of the elongate element for engagement against the periphery of the passage to provide a space through which the elongate element can move. The shroud is of flexible construction and is arranged to be progressively installed in position as the elongate element moves along the passage. The apparatus is adapted for introducing an inflation fluid into the region between the shroud and the elongate element in order to inflate the shroud and maintain it in engagement against the periphery of the passage.