COANDA SCREENS

Coanda screens are a great fit for remote locations – there are no moving parts and the gravity drop of the water keeps the screens clean. Although the end product is quite simple and requires very little maintenance, the design of these systems is far from simple. 

Elgin’s team of engineers has simplified this design process by establishing standard profiles, micro hydro packages, and some simple spillway designs to guide your team.

COANDA SCREEN FEATURES

APPROACH PLATE

The faster the water, the better the screen performs.  This approach plate accelerates the water to the screen surface using the Coanda effect.  An approach plate with a high incline and deep drop gives you the best result.  But higher inclines also have a higher chance of jumping the screen during high flow events, and deep drops on the Coanda screen are not optimal for overall site head loss (power generation or pressure flow).  Our team has balanced these variables in our standard Coanda screen profiles.

SCREEN WIRE

After water is accelerated over the approach plate, the bottom layer is “cut” by the screen wire to provide clean water to the collection chamber under the screen. This cutting action is what makes Coanda screens such an efficient use of space compared to a conventional intake that uses suction or head pressure. The slot opening and the tilt of the wedge wire drive out the size of the cut of water. There is a balancing act on how much water you are pulling vs. the self-cleaning properties, and our engineering team has tackled this problem for most sites in our standard Coanda screen profiles. Each site is unique, so our team is also ready to provide a custom solution when needed to achieve optimal efficiency.

COANDA SITE LAYOUT

Most Coanda screens can be found in run-of-river intake structures, which are small dams that have little to no water storage. While these sites are attractive for their minimal environmental impact, they also expose the intake system to heavy debris potential.

Debris loading can come in the form of large debris impacts from logs, boulders and other items that are mobilized by large flood events, as well as the slow, persistent wear from sand. To prevent damage from large debris, Elgin has heavy duty screen media options and protection bars to prevent direct impacts to the screen wire.

COANDA BOXES

Micro hydro clients are a unique breed – industrious, innovative, and frugal! After seeing countless videos of off-grid enthusiasts struggle with their intakes, Elgin decided to introduce our proven Coanda screen technology to the masses. 

Our Coanda boxes take the guesswork out of your intake. When power generation becomes essential to your homestead, you need an intake that can provide reliable water without the fuss of a conventional suction intake. Your turbine is also the backbone of your off-grid living, so the fine filtration and reliable water supply from Elgin’s Coanda box will avoid the clogging, wear, and sporadic shutdowns that plague many micro hydro systems.

COANDA BOX FEATURES

RUGGED SIMPLICITY

Although the fine filtration and reliable self-cleaning lend itself to very minimal maintenance, we make the inside of the box accessible to allow for periodic inspection and cleaning. Simply remove bolts on the downstream face and lift off the screen element.    

Mounting tabs make anchoring to the dam a breeze. Sized to accept most lag bolt and concrete anchors, you’ll have your system installed in no time.

The integrated sump and outlet pipe avoid construction time and cost at your site. After fastening the box in position, simply connect your rubber coupling and enjoy a reliable supply of clean water!

Elgin also offers large custom Coanda boxes that can be built around nearly any profile. Popular with clients that have a challenging construction site, these boxes can supplied in modular sections and anchored in a variety of ways. If you have a remote site with limited equipment access, contact our team for a custom solution.

Check out the videos below for installation tips and user reviews from some of our clients.