| 摘要 |
Dredging apparatus comprises a modular, submersible, vertically positionable crater sink mechanism operable to form a crater in a bed of material beneath a body of water. The crater sink mechanism comprises an elongated tubular housing closed at its upper end and having a dredged material intake opening at its lower end. An auger mounted in the material intake opening is rotatable by a reversible hydraulic drive motor and is axially positionable by a linear hydraulic motor. The inner end of the auger cooperates with the closed end of the tubular housing to define a mixing chamber. A clear water inlet port and a mixture outlet port on opposite sides of the tubular housing each communicate with the mixing chamber. The auger is rotatable in one direction to dig into and ingest material (fluidized by ambient water) through the material intake opening and transport it into the mixing chamber. A pump is connected to either one or both of the ports to effect flow of clear water (from the body of water) through the clear water inlet port into the mixing chamber wherein it mixes with ingested dredged material and to effect expulsion of the mixture from the mixing chamber through the mixture outlet port. Fluid pressure in the mixing chamber relative to that of the ambient water is determined by pump location and/or by the shape of the mixing chamber and its port. Fluid pressure is such as to prevent pressure-induced induction or expulsion of dredged material through the material intake opening. A jet nozzle near the material intake opening supplies clear water to further fluidize ingested material. Clear water is also supplied to clean anti-friction bearings supporting the auger. A control unit including a sensor causes momentary reverse rotation of the auger to expel ingested foreign matter which interferes with normal auger operation.
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