To meet the growing requirements of micro-tunneling projects worldwide, Brighway developed the slurry separation system, so called BWSP or Brightway slurry separation plant system, are specially designed for micro-tunneling separation with slurry mud conveyance in various ground condition, which is an important factor of every successful micro-tunneling operation.
Depending on the tunneling diameter, the excavation rate, the viscosity slurry rate, and geological conditions, Brightway offers efficient separation solutions.
In below introduction, we illustrate the operation of Brightway BWSP system, suitable for the wide range of geological conditions from very coarse to ultra fine.
The basic BWSP250 system is consisted of primary screen separation and secondary vacuum assisted cyclones for fine solids removal down to 60 microns/ 20 microns. The equipment are mounted on the 20′ standard container that operates as the storage tank. The tank is divided into 2 compartments. The slurry is pumped from the TBM / PIPE JACKING MACHINE to BWSP primary linear shaker, utilizing the High G force to allow the efficient conveyance of solids in the minimal foot print.
The high-G shaker is addressed with 3 wire woven stainless steel panels given the total screen area of 2.5 m². The screen separate the coarse material from the fluids and convey to the disposal. The screened slurry flow into the 1st compartment of the storage tank.
From here, the slurry fluids is pumped to the secondary vacuum assisted hydra-cyclones for secondary separation down to 60 microns. The fluids inside the body of the cyclones creates the centrifugal force.
The conical section increase the force and causes the large particles to settle. Solids accumulates at the bottom,when the weight of he solids exceeds the elastic force of the cyclone underflow, the solids dumps. Clean fluids and smaller particles are caught as the spiral and exit the vortex finder into the overflow pipe. Rather than small diameter, high pressure cyclones, the BWSP system utilizes the large diameter low pressure hydra-cyclones, the vacuum assisted cyclones separate the solids at low pressure, minimizing the share of effect that creates finer solids in the slurry which is more difficult to remove. The cyclone operates continuously without plug in.
The solids underflow exits to the high G force linear motion shaker screen for dewatering.
This dewatering screen deck utilizes the ultra fine wire woven stainless steel screen technology, dewaters and removes he ultra fine solids. The lighter material that smaller than 60 micro exits through the fluids overflow and discharged to the 2nd compartment of the storage tank.
Now BWSP system removes the most of solids bigger than 60 microns.
For geography conditions mainly with coarse and sandy materials, the above solution is capable to keep the slurry for operation. As the geography charges for finer silts and clays, further separation is required.
With the additional BWLW365G decanter centrifuge and BWVC vertical clarifier, it is possible to clean the slurry to 2 microns and maintain a close slurry circuit. In this case, the slurry containing the particles smaller than 60 microns is pumped from the 2nd compartment of the storage tank to the BWVC clarifier.
Prior to the slurry entering into the clarifier, the polymer flocculant is introduced by the means of BWFU flocculant unit. The treated slurry enters the charmber of the clarifier and flocked solids sinks to the conical bottom, and the clearer water rises up to overflow to return to the clean water storage tank. The flocked ultra fine solids accumulated and is pumped to the decanter centrifuge for dewatering.
The sludge enters the centrifuge though the feed tube. The BWLW365G decanter centrifuge is specially designed for the BWSP system. The centrifuge creates the high G force to increase the speed of the solids settling. and separate the sludge into the liquid and the solids phase.
The solids phase is mechanically extracted with the internal scroll and disposed. The liquid phase is discharged to the clean water storage tank from where it is finally transfered to the return tank.
The use of BWSP separation system ensures the operation of the TBM/ Micro-tunneling or pipe jacking and reduces both the environment impact and the disposal cost. The modular design provides flexibility in the limited work space for the large range of geography conditions and performance rate.
The use of combination of high G force shaker and conjunction of fine screen technology and consequently large open screen makes the BWSP solution as the efficient plan for the micro-tunneling industry.