Underwater suction dredger - has compensation pipe delivering water to zone near suction pipe mouth

摘要

The dredger is for the recovery of material such as sand and gravel from underwater, and has alongside the suction pipe (10) a compensation pipe (13). When working, the latter connects the water above the sand etc with a point (15) in the sand near the lower open end of the suction pipe, thus supplying water to this point to help loosen the spoil. More than one compensation pipe can be fitted, or there can be two concentric cylindrical components of different diameters, the inner one acting as the suction pipe and the outer one as the compensation pipe.