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Advanced Thickening TechnologyThickener Optimization Package
A Better Process SolutionWesTech Engineering has taken the next step in advanc-ing thickener technology with our Thickener Optimization Package (TOP). The TOP thickener design approach adds innovative features to the thickener to provide a better process solution.
•Even feed distribution •Optimal feed slurry dilution •Minimized flocculent consumption •Enhanced thickening •Improved dewatering and underflow control
Challenge: Short-Circuiting and High Floc Consumption An uneven current in the settling zone of the thickener can upset the quiescent conditions required for optimal gravity settling. These currents will carry solids to the overflow as shown below. Symptoms of a feedwell with uneven feed distribution include:
•Clarity problems due to short-circuiting •High flocculent consumption •Torque spikes due to uneven coarse-fraction
deposits
WesTech’s EvenFlo Feedwell converts the rotational momentum of the feed stream into a concentric radial flow.
Computational Fluid Dynamics (CFD) analysis demonstrating an uneven feed distribution from a conventional feedwell.
Solution:EvenFlo™ FeedwellA properly designed feedwell should provide energy dissipation as well as even distribution of the feed into the thickener.
WesTech’s EvenFlo design consists of a two-part feedwell system. An inner chamber converts the feed energy into a concentric radial flow. The main feedwell chamber then evenly distributes the feed into the sedimentation zone of the thickener.Patent Pending
WesTech’s Thickener Optimization Package - TOP™
Short Circuiting
Solutions:Dewatering PicketsWesTech’s unique combination of inclined dewatering pickets with a dewatering chamber provides a better method of removing water from the compacted solids. This results in higher densities and allows for stable
thickener control.
Underflow ControlThe TOP Vortex Recirculation system is used when the underflow density is below specification. The underflow slurry is recirculated until the correct underflow density is reached. The recirculation loop is then adjusted and the slurry is fed forward at the correct density. When the density drops below specification, the system reverts to the recirculation loop.
Challenge:Ineffective DilutionThickeners often require dilution of the feed to improve settling rates and floc consumption. Dilution systems designed to educt clear water from a single location can cause uneven flow patterns in the quiescent settling zone of the thickener.
Dilution systems driven by density differential can be less effective when the density outside the feedwell increases. Neither system allows for operator adjust-ments of dilution flow rates.
Challenge:Underflow Density ControlAn improperly designed underflow system is subject to fluctuations in density. Underflow density control can be influenced by a combination of operational and
design parameters which include:
•Bed level control •Underflow system design •Flocculent dose
Solution:AirLift™ DilutionWesTech’s AirLift dilution system uses an airlift pump to draw clarified water evenly from the thickener surface into the feedwell.
An even draw from multiple points prevents flow distur-bances in the quiescent settling zone while ensuring proper dilution/feed mixing inside the feedwell. Dilution flow can be regulated with precision by operator adjust-ment of the airflow to the system. Patent Pending
Underflow Control System
Flux curve showing optimum dilution
EvenFlo™ Feedwell and AirLift Dilution
Flow distribution patterns can be analyzed using Computational Fluid Dynamics (CFD). WesTech uses CFD technology as a tool to optimize the feed distribution system design.
This option allows thickener operators to target a specific dilution flow rate with controlled precision without upsetting quiescent settling conditions. Optimized feedwell dilution can minimize chemical consumption while maximizing the solids settling rate.Patent Pending
TOP™ Ten Design Features
The feedwell is a core component for every thickener. Energy dissipation and even feed distribution from the EvenFlo feedwell help to minimize short-circuiting in the sedimentation zone.Patent Pending
1 EvenFlo™ Feedwell
10 CFD Analysis
2 AirLift™ Feedwell Dilution
WesTech’s approach to elevated tank design is unique. An algorithm has been developed to simultaneously analyze parameters such as beam size, beam quantity, leg size, and leg location. Designs are verified using structural analysis software.
Customized Tank Design9
Even distribution into the sedimentation zone
from an EvenFlo Feedwell.
Short-circuiting in the sedimentation zone due
to a poorly designed feedwell.
WesTech’s Vortex recirculation system stabilizes underflow density control. An intermittent recirculation loop is used when underflow density is below specification.
WesTech’s TOP thickener drive design
includes direct in-line high-efficiency
reducer and motor stacks, a durable
precision bearing, state-of-the-art torque
protection, rake lifting capability, and a
customized design for each application.
Low profile rake support structures cut through the compacted slurry. Blade extension posts elevate the support structures from the solids transport zone. This results in lower energy consumption and more avail-able torque for solids transport.
As settling solids begin to compact together, water becomes trapped in the interstitial spaces between the solids. In contrast to vertical pickets, inclined pickets provide a progressive cavity that allows for a continuous and unhindered pathway for water to escape from the compacted zone.
Each TOP control system package is customized to meet the specific needs for a given application. Designs can range from a reactive control logic, with a high level of operator interface to a proactive control logic, with complete automation and minimal operator interface.
7 Vortex Recirculation
6 Low Profile Raking System
The geometry of the TOP dewatering chamber provides additional solids residence time and a larger inventory for compacted solids. Inclined scrapers are used for further dewatering within the chamber.
8 Dewatering Chamber
4 TOP Control System3 Extreme Duty Drive
5 Inclined Dewatering Pickets
WesTech Thickeners Each WesTech thickener type can include any combination of the TOP™ Ten thickener features.
HiFlo™ High Rate ThickenerWesTech has a worldwide installation base with appli-cation experience across the spectrum for minerals and industrial high rate thickening applications.
WesTech’s HiFlo Thickener equipped with the TOP Ten features is an industry-leading, application-specific solution that will provide:
•Lower flocculent consumption •Consistent underflow density •Stable operation
AltaFlo™ Ultra High Rate ThickenerThe AltaFlo is a rakeless thickener that uses rapid dewatering in the hindered settling zone to achieve a very high settling rate. The AltaFlo typically operates at twice the settling rate of a high rate thickener. The geometry of the unit provides for a deep compaction bed, allowing the thickener to achieve relatively high densities. The AltaFlo has the following advantages:
•Smaller footprint •Lower cost alternative •No operational spares
Titan Traction™ ThickenerThe Titan Traction thickener is specifically designed for large flow rates and high tonnages where center drive units become uneconomical. The rake arm is driven by a tractor mounted on the rim of the thickener tank.
WesTech employs unrivaled state-of-the art technology to address the complexity of these super-sized thickeners. Designs are verified by integrating the results from Com-putational Fluids Analysis, Finite Element Analysis and Mechanical Event Simulation.
•Diameters exceeding 100 m •Flow rates exceeding 20,000 m3/hr •High torque capacity
WesTech offers a full range of thickening equipment to meet the requirements for any minerals or industrial appli-cation. The unique characteristics of each slurry dictate the process design parameters for our thickeners. The TOP Ten design features can be used in any combination with a WesTech thickener to offer a customized design with reliable performance.
Contact WesTech to find the right thickener for your processing needs.
HiDensity™ Paste ThickenerWesTech’s HiDensity thickener produces non-settling thickened tailings with lower viscosities and underflow concentrations than what is produced in the Deep Bed paste thickener. The HiDensity thickener offers the advan-tages of paste and thickened tailings for large tonnages.
Reduced viscosity associated with the underflow concen-tration of the HiDensity thickener results in lower pumping costs – an important factor for deposition areas far from the plant.
Deep Bed™ Paste Thickener
The WesTech Deep Bed Paste thickener produces non-settling and non-segregating underflow with the maximum rheology (density) possible. WesTech is a leader in paste technology with diverse application experience and a large installation base.
•Maximize water recovery •Enable surface stacking •Reduce tailings impoundment size •Improved CCD circuit product recovery •Reduce environmental impact
YIEL
D S
TRES
S
UNDERFLOW PERCENT SOLIDS
HiFlo™ High Rate
Titan Traction™
HiDensity™
AltaFlo™ Ultra High Rate
Deep Bed™ Paste
YIELD STRESS C
URV
E
Which Thickener is Right for Your Application?
© WesTech Engineering, Inc. 2011
WesTechProcess Equipment. Process Driven.
Represented by:
Call for Your Thickener Optimization Needs.North AmericaTel: 1 801 265 1000Fax: 1 801 265 [email protected] S. West Temple Salt Lake City, Utah 84115, USA
South AmericaTel: +55 11 3129 5226 Fax: +55 11 [email protected] da Consolação 1025 5o Andar, ConsolaçãoSão Paulo, SP01301-000, Brazil
ChinaTel: +86 236 541 6377 Fax: +86 236 540 9075 [email protected] 17-11, Wangfujing Building B Shapingba, Chongqing 400030, China
South AfricaTel: +27 11 794 5205Fax: +27 11 794 [email protected] 1, Bush Hill Oce ParkJan Frederick RoadRandpark Ridge, 2156Johannesburg, South Africa
Thickener Retrofits and UpgradesDo you need to upgrade your existing thickener? WesTech has the ability and experience in retrofitting thickeners of all types from other manufacturers. Upgrade your thickener with any combination of WesTech’s TOP™ Ten thickener features to get more out of your existing thickener.
Extreme Duty DrivesWesTech’s extreme duty drive units are proven workhorses in the minerals and industrial processing industries. Under the harshest operating conditions, WesTech’s drives perform with minimal operator attention and provide long-lasting service.
WesTech has upgraded many existing thickeners with our precision bearing drive units. With every drive retrofit, WesTech visits the site to inspect the existing equipment, record detailed measurements, and plan for any special installation requirements.
•Meets the demands of extreme environments •Robust design for longer drive life •Retrofits for drives from any manufacturer •Qualified field service for fast installations
Retrofits and Upgrades
