The ship unloader is a special machine that can lift and unload the bulk material from the cabin to the shore. According to different conveying machinery and reclaimer, there are many types of ship unloader, such as screw ship unloader, chain bucket ship unloader, grab ship unloader and so on. Using ship unloader can improve unloading efficiency, reduce dust pollution and protect the environment.

Chain bucket ship unloader is suitable for unloading bulk materials such as limestone, coal, phosphate, ore and raw sugar. The density and granularity of these materials are more suitable for the chain bucket excavation and transportation. Chain bucket ship unloader has high unloading efficiency, little pollution to the environment and low energy consumption

Grab ship unloader is a kind of bridge crane that grabs materials from the cabin and disloads them to the hopper of the plane by using the grab driven by the moving trolley. It belongs to the bulk batch type (or periodic) ship unloader. It is composed of metal structure, four reel mechanism, amplitude mechanism, vehicle running mechanism, grab and hopper feeding system, water spray dust system, mobile cab and other components. It is a common ship unloading equipment, suitable for unloading all kinds of bulk materials 2.

The main differences between chain bucket ship unloader and grab ship unloader are as follows:
Chain bucket ship unloader is a continuous bulk ship unloader which uses chain bucket to dig materials from the hold of sea ships and unload them to the dock through the on-board conveyor system, while grab ship unloader is a batch bulk ship unloader which uses grab bucket to grab materials from the hold of sea ships and unload them to the dock through the boom or conveyor arm.
The unloading efficiency of the chain bucket ship unloader is higher than that of the grab ship unloader, because the chain bucket can continuously excavate and transport materials, while the grab needs to take off and open and close frequently.
The environmental pollution of the chain bucket ship unloader is less than that of the grab ship unloader, because the material conveying path of the chain bucket ship unloader is basically closed, and the dust is not easy to escape, while the material of the grab ship unloader is easy to produce dust and splash when moving in the air.
The installed capacity of chain bucket ship unloader is smaller than that of grab ship unloader, because chain bucket requires smaller driving force, while grab requires larger lifting gravity and opening and closing force.

Chain bucket ship unloader is a kind of continuous ship unloader developed rapidly in the last ten years. At present, this type of product is being developed and produced in Germany, Japan and China. The chain bucket ship unloader developed in our country has two forms: one is single arm type and the other is double arm type. Chain bucket ship unloader is used in the following terminals:

Dalian Port: 1500 tons/hour single arm chain bucket ship unloader was used.
Xiamen Port: 2000 tons/hour double arm chain bucket ship unloader was used.
Port of Dongguan: 1000 tons/hour single arm chain bucket ship unloader was used.