WNX Series Slurry Treatment System for Shield Machines
The WNX-3000 slurry separation plant is made up of three WNX-1000 units. Each WNX-1000 consists of a coarse screening unit, a primary circulation unit and a secondary circulation unit, giving a combined slurry throughput of 3,000 m³/h. The modular design allows the system to be split or combined according to the specific requirements of a project, giving it broad engineering adaptability.
The WNX-3000 system comprises two main parts: the slurry separation system and the slurry conditioning system. Its primary function is to separate, stage by stage, the slurry discharged during tunnelling that contains sand, gravel and soil. The separated gravel and soil retain only a small amount of moisture and can be hauled away directly, while the slurry fraction, once conditioned, can be returned directly as feed for the tunnelling equipment, keeping the shield machine running normally.
How the WNX-3000 Works
When a slurry balance shield machine begins tunnelling, slurry discharged by the mud pump passes through the WNX-3000 separation plant and then into a settling tank for overflow settling. Spoil particles screened out by the dewatering screens in the primary and secondary circulation units can be hauled by truck to a designated spoil site after environmental testing. If the slurry density is too high, clean water is added to dilute it; if it is too low, a high-speed slurry mixer adjusts it, and once the density has been raised the slurry is pumped back to the shield machine.
Reliability
The slurry treatment system is critical to keeping a shield machine tunnelling, and it must be dependable throughout construction. The WNX-3000 is built from three WNX-1000 units running in parallel, so the probability of all three failing at once is very low. In addition, the slurry conditioning tank holds a substantial volume of slurry meeting the shield machine’s requirements, and overflow settling in the settling tank can also supply a large quantity of slurry fit for feeding. Even in the unlikely event that all three WNX-1000 units are out of service, the shield machine can still advance one to two rings normally, leaving ample time for repair — Winner undertakes to complete repairs within two hours. The WNX-3000 therefore keeps construction on schedule.
The modular design of the slurry system gives it a simple, well-proportioned structure, a small footprint, centralised spoil handling, straightforward operation, stable and reliable quality and a low failure rate. Processing capacity is specified with a generous margin, and the primary and secondary systems can be switched between series and parallel operation.
Where Reliability Comes From
- Reliability of the overall design — prompt handling of spoil slurry and tolerance of varying slurry quality.
- A generous capacity margin, including spare complete machines and spare parts.
- Reliability of the equipment itself in performance, quality and service life.
- Switching between equipment groups through the pipework and valve assemblies, so that each group backs up the others.