Bulk material conveying for a pneumatic dredger

摘要

A pneumatic dredger bulk conveyor of the type wherein a conveyor line is formed by a first circular outer tube and a first inner tube telescopically slidable therein and a pressure line is formed by a second outer tube fixed to the first outer tube and a second inner tube telescopically slidable in the second outer tube in coordinated movement with the first inner tube, the improvement which comprises an upper circular guide member formed at the upper end of the first inner tube and closely spaced from the first outer tube defining a first circular interspace therewith, the first inner tube having below the upper guide member a polygonal profile forming a second interspace with the first outer tube having a greater cross sectional area than the first interspace and constituted by a plurality of first segmented passages of greater width than the first interspace and each of which is bounded by an arc of the first outer tube and a plane of the polygonal profile.