Coanda Intake Half Screen

The PowerSpout Coanda intake screen removes rubbish, stones, leaves and aquatic life forms from the flow prior to entering the supply pipe (penstock). This is often a requirement of environmental protection agencies. A poor intake is normally the cause of most hydro turbine system problems. Poor intakes may allow small stones to enter the penstock that can cause serious damage to the Pelton rotor or cause the jets to suddenly block resulting in severe water hammer that can rupture pipe and fittings.

Our Coanda intake screen is not limited to small hydro schemes, it can also be used for domestic, farm, village and small town water supplies.

Our Coanda intake screens are designed to provide low maintenance screening solutions for water intakes without the need for any moving parts. The self-cleaning ability and high abstraction flow capacity is due to the shape of the screen and the arrangement of the wedge wires that make up the screen.

The Coanda screen uses the Coanda effect, which is the phenomena in which a jet flow attaches itself to a solid surface and remains attached, even when the surface curves away from the initial jet direction. The screen is built from wedge-shaped wires that have suitably angled faces to which the flow attaches.

Water is directed over the screen in a fast moving sheet, and the bars deflect it into a tank below whilst debris continues straight on and is washed off by the surplus flow.

Water and some fine silt particles (<1.5mm) pass through the screen, whilst larger silt and debris is excluded and deposited downstream. During times of low river flow the screen capacity may be greater than the available water. Under these conditions debris can build up on the lower parts of the screen. This will be washed off the next time the river flow rises above the screen capacity.

You can order your intake so that the pipe can attach on the left hand side (LHS), right hand side (RHS) or in the central location as shown below. The central option is possible but not advised, unless there is no space for a LHS or RHS fitting.

If possible you should avoid a sharp elbow connection to the intake casing. Once the pipe is connected to the intake it can be concreted over to help protect from floods. It is very unlikely you will ever need to separate the intake tank from the pipe again.

Each complete intake comes with:

• Black roto-molded LDPE casing
• Coanda screen 
• Outlet pipe fitting based on your selected size option
• Acceleration plate and securing tube
• Low entry-loss (bell-mouthed) internal fitting
• Vortex breaker plate (only on 1/2 screen version)
• Securing anchors so it can be concreted into position

Screen Specifications:

• Material: 304 stainless steel
• Screen gap: 1.5mm
• Wedge wire tilt angle: 5 degrees
• Wedge wire width: 2mm
• Wedge wire depth: 3mm
• Supporting bar: 3mm wide x 5mm deep at 20mm spacing
• Width x length: 380mm x 188mm 
• Effective width x length installed: 360mm x 168mm
• Screen angle relative to flow rate: 0 to 40 degrees (we recommend 25-35 degrees)
• Approved nominal flow: 8l/s
• Rated load: A person of 100kg can stand on the screen without damage.

For detailed dimensions of the whole assembled intake please refer to the product manual.

This product does require assembly.

We also offer a full screen intakes in both a cube configuration and in a rectangular configuration.

You can find the product manual here, and also our general intake guide here.

Refer to PowerSpout Document Index Links for a complete index of documents.