There are two types of subway shield machines: earth pressure balance shield machine and mud-water balance shield machine. Among them, the earth pressure balance shield machine does not need to separate the mud and water. Its essence is to excavate the soil, and the mud and water balance shield machine needs to separate the mud and water.
The principle of the mud-water balance shield machine is to stir the relatively moist soil at the front end of the shield into mud, and then pump out the mud to form a tunnel. The extracted mud needs to be separated from mud and water for environmental protection, and the water in it needs to be reused.
The mud-water separation needs to use a mud-water separator. The mud-water separator is divided into three layers, and sieves out the stone clods of different particle sizes, and then performs pressure filtration to realize the separation of soil and water. In this way, the pollution caused by the direct discharge of muddy water is avoided, and the reuse of water is also realized, and the separated soil can also meet the standard of safe discharge, so that the waste residue can be properly treated. Compared with the earth pressure shield machine, the structure of the mud-water balance shield machine is more complicated, and the mud-water separator also occupies a large area, so it is relatively less used, but in the wetter strata, such as Shanghai and other coastal areas, generally only can use the mud water Balance shield machine.
According to whether the excavation surface is closed, the shield machine can be divided into two types: closed type and open type. According to the principle of balancing the earth pressure and water pressure of the excavation surface, the closed shield machine can be divided into: earth pressure type and mud water type. According to the excavation method, the open shield machine is divided into: hand excavation, semi-mechanical excavation, and mechanical excavation.
In the shield machine, the mud-water separation treatment is required for the mud-water balance shield machine. The mud-water balance shield machine uses mud-water to resist the water pressure and earth pressure of the excavation surface to maintain the stability of the excavation surface, control the deformation of the excavation surface and the settlement of the foundation; form a weakly permeable mud film on the excavation surface to maintain the water pressure Effective on the excavation face. The effect of the mud-water separation is achieved by the mud-water treatment system related to the shield machine.
The mud pumped by the mud pipeline during the tunneling of the mud-water shield machine is transported to the mud-water separation station for separation:
Through the primary screening, most of the solid stones and mud blocks are separated;
After the first-stage separation, most of the clods above 3mm are separated, and the separated mud flows into the slurry collection tank, and then is pumped to the second-stage cyclone by the mud pump for separation;
The accuracy of the secondary separation is 70~74μm. After the secondary separation, the mud is pumped to the tertiary flow device again for separation ;
The separation accuracy of the three-stage cyclone is 20-25 μm. After the three-stage separation, the mud flows back to the pulping tank, and after pulping, it is transported to the knife excavation by the mud pump for placement.
After the waste slurry is filtered and separated by a filter press as required, the slurry particles larger than 5 μm in the slurry are basically separated, and then the sedimentation can meet the discharge requirements.
KOSUN HDD Mud Recovery System is developed, designed and produced by our company to meet the requirements of trenchless technology at home and abroad. It is used to purify the mud returned from the ground during the horizontal directional crossing process. The large particle size drill cuttings are separated by solid phase control equipment such as shale shaker and mud cleaner, and the required mud material is added by the mud mixing device, and the mixing and circulation are uniform to meet the performance requirements of reuse. The mud pump is pumped into the horizontal directional drilling system is recycled repeatedly. KOSUN HDD Mud Recovery System can significantly improve the efficiency of mud treatment, reduce the mud cost of horizontal directional drilling, and greatly improve the drilling speed.
Advantages of KOSUN HDD Mud Recovery System
Based on the technical experience of KOSUN in the solids control industry for more than 30 years, combined with in-depth market research, the designed mud recovery system has a reasonable structure, good processing technology and a wide range of applications.
The multi-functional integrated design can meet the functions of mud cleaning, recycling and reuse, mud configuration and storage, and at the same time greatly reduce the overall size of the tank system to meet the site and space requirements of horizontal directional drilling.
The electrical system is explosion-proof, dust-proof and rain-proof to ensure construction safety and quality.
The tank body is simple and compact in structure, light in weight, and the corridor and guardrail can be folded or disassembled for easy transportation and installation.
KOSUN Machinery has obtained API and ISO certification of American Petroleum Institute, EU CE certification, Russian export certification, and ISO14001 and ISO18001 certification of environmental safety system, which can meet the export standards of all countries in the world.
Linear Dewatering Shale Shaker – Construction Mud Solid-liquid Separation Equipment Linear Dewatering Shale Shaker is specially designed to separate larger and coarser solid particles. The construction mud enters the shale shaker through the feeding funnel, and separates large-diameter solids such as large stones. The screen on this shale shaker has a longer lifespan than traditional woven screens.
Double-layer mud Shale Shaker After being screened by the Linear Dewatering Shale Shaker, the liquid phase enters the Double-layer mud Shale Shaker again. The Double-layer mud Shale Shaker is a two-stage separation. It first enters the bottom layer of the Double-layer mud Shale Shaker. The mesh number of the bottom layer is smaller, and the coarse particles are further screened. The mesh number of the upper screen is higher, and the liquid phase passing through the bottom screen enters the upper screen again, and the effect is better.
Mud cleaner The liquid phase screened by the Double-layer mud Shale Shaker is pumped to the mud cleaner. The mud cleaner consists of two 10-inch desander cyclones and 12 4-inch desander cyclones plus a shale shaker. The liquid phase first passes through the desander cyclone, and then enters the desliming cyclone. After separation by the mud cleaner, the material conditions for entering the centrifuge are reached.
Decanter centrifuge The separation capacity of the decanter centrifuge is more refined. In order to ensure a good use effect, the requirements for the materials entering the centrifuge are relatively strict, so the front coarse screen, fine screen and cleaner are processed. The centrifuge can separate solid particles above 2-5um. After the centrifuge treatment, it meets the customer’s requirements.
Flocculation dosing system The flocculation dosing system is the icing on the cake. When the level required by the customer is higher, the flocculation dosing system can make the centrifuge more effective.
If you have any inquiries about equipment needs or solutions in this regard, you are welcome to call us.