coanda screens - elgin equipment group
DESCRIPTION
Elgin Equipment Group's Coanda Screens are Tough, Proven Solutions for a variety of applications including small hydro, micro hydro, and low head sites.TRANSCRIPT
EEG WaterCoanda Screens
Coanda ScreensCoanda Screens• Inclined screens that use overflowing water to stay clean• Tough screens with very low maintenance• Clean water falls through; fish & debris pass over
Coanda Screens
Coanda screens are tilted profile wire bar screens. The shape of the screens allows the screens to remain clean with little or no mechanical cleaning. The operation is enhanced by the Coanda Effect as the screens catch only the bottom layer of water. The tilted profile wires of the Coanda Screen slice off thin layers of water, allowing debris and fish to pass safely over the screen as water falls through the screen.
Coanda Screens Value Proposition
Simplify the intake with Coanda Intake design
Cost Item Typical Savings
Desilting structure Cap-Ex 10%
Desilting structure excess flow 5%
Coanda operating cost 5%
Eliminate the Desander
Coanda Screen Performance Testing
Key Results:• Defined adjustments for full
scale• Determined impact of flow in
excess of design• Determine impact of high
debris
US Bureau of Reclamation Testing
Key Results:• Developed
governing equation
• Determined impact of various parametersCSU
Testing:• Tested one
meter of screen for flow, cavitation, and debris
Debris laden water over a 2mm screen
Debris over the toe
Fine debris through the
screen
Overflow Debris Testing
Design Guidance: Coanda Screens
Head
at
Zero Bypass Case
Bypass Flow
Gross Head for Intake
Θ
Design Guidance: Coanda Screens
3 Decisions:• Accelerator Size and
Shape• Screen Slot Width• Design Loading
Design Guidance: Coanda Screens
3 Decisions:• Accelerator Size and
Shape• Screen Slot Width• Design Loading
Finer
Safety
Factor
Coanda Screens: Debris Passage
Fixed frame rib designed for extreme condition
Replaceable Screen Panel. Design case considerations below
Cost of stainless steel to
withstand extreme
design case
Cost of mobilization, material, and
supply for more
frequent repairs
3 Decisions:• Accelerator Size and
Shape• Screen Slot Width• Design Loading
Coanda Screens: Debris Passage
The boulders and logs pictured here passed over the screen without reducing flow or damaging the screen.