| 摘要 |
<p>Air operated dredging apparatus comprising a submerged pumping unit adapted to be dragged along an underwater bed which unit includes at least two pumping chambers periodically filled with loose material in admixture with water entering the chamber through a duct connecting a dredging shovel to the chamber, and emptied by feeding compressed air into the said chamber. A check valve is provided on the duct upstream of the entrance to the chamber whereby escape of air through the duct and the shovel is avoided.</p> |
