Trailing suction hopper dredger (TSHD)

英文Trailing suction hopper dredger (TSHD)

中文 (征集中)

英文释义

The trailing suction hopper dredger is nonstationary dredger, which means that it is not anchored by wires or spud but it is dynamically positioned; the dredger uses its propulsion equipment to proceed over the track. It is a shipshaped vessel with hopper type cargo holds to store the slurry. At each side of the ship is a suction arm, which consists of a lower and a higher part, connected through cardanic joints. Trailing suction hopper dredgers are used for maintenance work (removal of deposits in approach channels) and dredging of trenches in softer soils. The dredger is powered by two Wärtsilä 6L32 engines, each of 2760kW MCR output at 750rpm. Each engine drives through reduction gearbox 2500mm diameter CP propeller running at 230 rpm in the nozzle. The maximum power available for propulsion is 2000kW per propeller. The single dredge pump is driven directly off the forward end of the starboard main engine through a clutch coupling, a long shaft and a two-stage variable-speed gearbox. An equivalent arrangement is employed for the twin jet pumps on the port side. TSHD has several special features, the main one being a drag arm which works as vacuum cleaner. Drag arm consists of a suction bend, lower and upper suction pipes connected via double cardan hinge and a draghead. The suction bend is mounted in a trunnion which forms part of the sliding piece; as the pipe goes outboard the sliding piece enters the guide on the hull and is lowered until the bend is in line with the suction inlet below the waterline. The suction pipe can be equipped with an integral submerged dredge pump. Submerged dredge pumps have become more and more popular with operators of larger trailing suction hopper dredges. Locating the dredge pump in the suction pipe positions is much closer to the seabed than a conventional dredge pump housed in the hull. The drag arm is hoisted outboard and lowered to dredging depth with the aid of gantries. When not in use, it is lifted above the main deck level and pulled inboard with the hydraulically powered gantries for storage

中文释义

(征集中)

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