In the dredging of lakes, geothermal, drilling, piling, tunneling and other operations, how do we separate the sand and water we pumped?
The separation of sand and water usually takes the following methods:
1. Natural sedimentation.
Because sand and water have a large density difference. By putting still for a long time, the sand in the water can be naturally settled and the upper layer of water can be pumped out to achieve the separation effect of sand and water. However, this method is relatively inefficient, and the separated sand still contains most of the water. If you require a high efficiency and a low moisture content of the sand, this method should not be used.
2. Filtration separation
Allow sand and water to pass through the filter or filter cloth quickly, and the sand is successfully intercepted on the other side of the filter to achieve separation of sand and water.
The equipment commonly used in this method includes a vacuum filter and frame filter press. The efficiency is high, but the filter cloth needs to be replaced frequently, and the cost of consumables is high. Moreover, the separation effect often depends on the particle size of the sand particles. When the sand particle size is too small, it is not easy to separate, usually it will block the filter holes, reduce the working efficiency of the equipment, and at the same time, the filter needs to be replaced regularly which resulting in large labor costs, and the working environment is also dirty. This method is not suitable for projects with large sand particle size distribution and large variations.
3. Centrifugal separation
Centrifugal separation is the use of high-speed rotating equipment that produces powerful centrifugal forces that tend to be thousands of times larger than their own weight.
By the action of centrifugal force, the sand and water are quickly separated and then discharged through a specific outlet to achieve the purpose of sand and water separation. The equipment commonly used in this method is: horizontal spiral discharge sedimentation centrifuge (referred to as: decanter centrifuge).
The use of decanter centrifuge for solid-liquid separation is highly efficient and can be operated continuously for 24 hours, with automatic feeding and automatic unloading. he separated sand has low water content and clear water, which can meet most project requirements.
At present, most centrifuges fabricated by manufacturers equipped with full-automatic control system, thus saving a lot of manpower. It is widely used in field wastewater, piling wastewater, lake dredging, tunnel engineering and other fields.