Classification of mechanical dredgers

Mechanical (dry) dredgers mainly use various excavating machinery to excavate, vertically lift, and horizontally transport underwater sediment to achieve the purpose of dredging. including the following:

1. Grab dredger

Grab dredgers are generally used for projects with small earthworks or parts of the earthworks in large projects. Port basins, bends in waterways, and parts that cannot be dug by trailing suction dredgers can be removed by grab dredgers. Obstacles in the construction area can be removed by grab dredgers, which can be carried out accurately and safely by grab dredgers. Grab dredger boats are suitable for excavation in deep-water areas and are also suitable for sand and gravel mining.

2. Bucket (backhoe) type dredger

A bucket (backhoe) dredger is suitable for excavation of hard soil, such as the removal of rocks and boulders, underwater dams, and old revetment facilities. The main equipment of the bucket (backhoe) dredger is an excavator composed of a heavy bucket, a diesel engine, and a hydraulic system. The backhoe is mounted on a punt or on a jack-up. The excavated soil is transported on barges.

3. Chain bucket dredger

The chain bucket dredger consists of barges with mud wells and six mooring systems. The mud bucket is installed on the continuous bucket chain. Driven by the rotation of the upper guide wheel at the upper end of the bucket bridge, the bucket chain runs continuously. The upper end of the bucket bridge is supported on the elevated deck, and the lower end is placed in the water. Make it rise and fall. When dredging, the soil excavated by the mud bucket and loaded into the mud bucket is transported to the top of the bucket bridge by the mud bucket. When the mud bucket rotates with the rotation of the guide wheel, the dredged soil is poured into the mud well and transported through the mud chute to the mud barge tied to the side of the dredger. When dredging, use the side anchor cable of the dredger to control the dredger to move back and forth laterally between the trenches. Use the bow anchor cable and stern anchor cable of the dredger to control the longitudinal movement of the dredger.

Bucket dredgers are ideal for digging clay and other sticky materials, as well as gravel and other coarse particles. It can be used for laying pipelines, digging trenches for cables, etc. It is suitable for dredging of inland waterways and harbor basins. The number of equipped mud barges and the capacity of mud barges are related to the productivity of dredgers, the distance of unloading mud, and the speed of tugboats (or self-propelled mud barges). Since 1965, due to the emergence of new dredging machinery, the number of chain bucket dredgers has gradually decreased, and now only a small number of chain bucket dredgers are used in special construction.