What is Chain bucket continuous ship unloader?

Chain bucket continuous ship unloader is a type of loose material continuous ship unloading machinery that uses a chain bucket to excavate materials from the sea side cabin and unload them onto the dock through an onboard conveyor system.

Chain bucket continuous ship unloader is a type of continuous ship unloading equipment that has rapidly developed in the past decade. Currently, Germany, Japan, and China are all developing and producing this type of product.

There are currently two forms of chain bucket unloaders developed in China. One is the suspension chain type, which is suitable for deck barges.The chain bucket of the suspended chain bucket unloader does not have a rigid support in the material retrieval section and is suspended. The hopper that falls on the deck for operation can float up and down with the deck when the ship is bumpy, so the hopper can work closely against the deck and has the ability to clear the warehouse.

Another type is an L-shaped chain bucket ship unloader, where the chain bucket excavates and lifts the material to the top. The material is unloaded onto the boom belt conveyor through a spiral funnel unloader and transported to the rear. The L-shaped feeding head can rotate, and the boom can pitch and rotate. Through automatic control, it is possible to ensure that the material retrieval head moves along a certain route.

According to the materials unloaded, it can be mainly divided into two types: ore unloading and coal unloading. There are also specially designed models that can balance ore unloading and coal unloading. Usually, the rated unloading capacity of coal unloaders with chain bucket continuous unloaders is between 1200t/h and 2500t/h, while the rated unloading capacity of ore unloaders is between 2000t/h and 4500t/h.

The characteristics of chain bucket continuous ship unloaders

Compared with traditional grab ship unloaders, its main advantages are:

High unloading efficiency: Traditional bulk cargo handling systems have achieved continuous operation of all handling machinery except for the unloading machine. The application of chain bucket continuous unloaders has made up for the weak links in bulk cargo handling systems.

In terms of control, the chain bucket continuous ship unloader can be operated semi-automatically to further improve the efficiency of unloading and simplify the operation of the driver. The average efficiency of single ship unloading with chain bucket continuous unloaders can reach over 70% of the rated capacity, while grab bucket unloaders are usually only 55-60%.

Low environmental pollution: The environmental characteristics of chain bucket continuous ship unloaders are mainly reflected in their control of dust.

During the operation of the chain bucket machine, the head excavation part is always inside the cabin. During excavation, a sprinkler system can be equipped to effectively control the dust generated during the excavation process.The entire transportation process of materials is carried out in a sealed space, and a sprinkler system is installed at each transfer point to effectively suppress dust overflow. Because, except for the reclaimer head, the material conveying path is basically closed, making it difficult for dust to escape. There is no frequent braking operation at work, so the noise is not significant.

Low energy consumption: Compared to traditional bulk cargo handling systems, chain bucket continuous unloaders work continuously without acceleration or deceleration during the operation process, and the vertical lifting section mainly focuses on material work (balancing the weight of the lifting part of the chain bucket), with relatively small power of each mechanism.

Therefore, compared to traditional unloading equipment with the same capacity, the overall installed capacity of the chain bucket continuous unloading machine is relatively small. The power consumption is about 70% of that of the bridge type grab ship unloader; Moreover, the use of clearance machines is minimal, and the fuel consumption is about 50% of that of bridge type grab ship unloaders.

Low quality: Its quality is generally smaller than that of grab ship unloaders with the same extension distance and productivity (especially crane trolley type grab ship unloaders).

The working legs are lowered to reduce the construction cost of the dock. The tail of the chain bucket continuous ship unloader is equipped with a counterweight structure to maintain the stability of the entire machine during operation.Due to the effect of counterweights, the center of gravity of the entire ship unloader (compared to the bridge grab ship unloader) is relatively small under various working conditions, which brings the advantage of lower working leg pressure (the higher the unloading efficiency, the more obvious this feature is).According to the statistical data of existing models, the working leg pressure of chain bucket continuous ship unloaders is about 10% to 20% lower than that of bridge grab ship unloaders of the same specifications.

Reducing the working leg pressure of the ship unloader makes dock construction more economical, which can directly reduce the construction cost of the dock. The reduced consumption of materials, energy, and labor in dock construction is also a protection of the environment. Therefore, from the perspective of overall environmental protection, the application of chain bucket continuous ship unloaders has the characteristic of comprehensive environmental protection.

Types of cargo suitable for chain bucket continuous ship unloaders

Chain bucket unloaders can be used to unload materials such as limestone, coal, phosphate, ore sand, and raw sugar. Currently, the maximum unloading productivity in China has exceeded 4500t/h, and the maximum ship type for unloading is a 300000 ton seagoing vessel.

The chain bucket capacity of the chain bucket continuous ship unloader is relatively small, the structure of the reclaiming device is complex, and it is prone to blockage, making it unsuitable for unloading viscous materials. It is sensitive to oversized and irregular block materials, and the particle size of the unloaded materials is generally below 300mm.

The structure of a chain bucket continuous ship unloader

The chain bucket ship unloader mainly consists of the following parts: chain bucket material retrieval lifting mechanism, bucket elevator rotation mechanism, material retrieval mechanism, boom rotation mechanism, boom pitch mechanism, walking mechanism, belt conveyor system, and gantry structure.

Chain bucket unloaders are usually divided into two categories based on the structural characteristics of their material retrieval and lifting parts. One type is achieved by the same mechanism for material retrieval and lifting, while the other type is achieved by their respective mechanisms for material retrieval and lifting.

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