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2026

Working principle of a sand-dredging vessel

Chain‑bucket dredgers rely on four‑wheel or five‑wheel buckets to cut and break up the riverbed, then extract river sand via the bucket chain.

Chain‑bucket dredgers cut and break the riverbed using four‑ or five‑bucket wheels, then extract river sand via chain buckets. They collect underwater sand and gravel with bucket or chain buckets, separate the material through screening, and convey the finished sand to a designated area via conveyor belts, while impurities are discharged through a separate channel.
The typical structure of a bucket‑type dredger comprises a bucket chain made up of buckets and chain links, which is looped around the upper and lower guide wheels on the bucket bridge. The upper guide wheel is connected to the drive system, while the lower guide wheel is suspended by a winch via cables to control the excavation depth. During operation, driven by the upper guide wheel, the bucket chain continuously performs cutting, loading, and lifting underwater. After passing over the upper guide wheel on the bucket bridge, the buckets discharge their load under gravity into a belt conveyor, which then transports the material to a transport vessel or discharges it onto the shore.
The upgraded sand–gravel mixture must be screened to remove impurities, with screening methods including self‑vibrating and drum‑type systems. Some dredgers are equipped with magnetic separation systems; the magnetic field strength of these separators typically ranges from 3,800 to 4,500 gauss, enabling the adsorption and removal of iron‑bearing materials. The tailings discharge system removes the screened tailings from the operation area, employing gravity‑flow, belt‑conveyor, or pump‑based methods.

The process flow of a gold dredger

The centrifugal principle of gold‑selecting centrifuges

The process flow of a gold dredger

The centrifugal principle of gold‑selecting centrifuges