Mine local ventilation flexible ducting - coaxial lengths pulled out starting from outer most length ends located

摘要

Local mine ventilation flexible ducting extends by means of a number of coaxially stored lengths connected to each other at the ends to permit their being drawn out to form ducting of the desired length. It is always the outermost length (9) which is drawn off those inside (7, 3), the outward ends (6) of these inside lengths being anchored until the length immediately above them has been fully removed. The ducting is preferably made by folding back the outer layers progressively, with reinforcement (20) provided on the outward end (6) of each of the layers lying inside an outer length (9). The reinforcement should take the form of strips (20) located in pockets (21) which are open in the pull-out or drawing-off sense.