Hydropower / Coanda Screens
The Hydropower / Coanda Screens, also known as the overflow sieve (or weir) screen and diversion screen, were developed to accommodate the need for a remotely located intake screen in mountain streams supplying water to a mini hydro scheme. The system was required to be virtually maintenance free from screen fouling by water borne debris and capable of delivering sufficient particle free water to drive the turbine efficiently without damage.
This concept has found its way into water supply schemes for villages and towns, mainly for smaller applications. The patented concept and design minimises debris impingement by maintaining enough water flow over the screen surface to sweep any solids off the end of the screen. As long as the upstream pool surface is 110 mm (4.3 in.) above the sieve or weir crest, adequate flow will occur. If the pool surface exceeds 110 mm (4.3 in.), the excess water will pass over the screen and on downstream. If the head over the weir crest falls below 110 mm (4.3 in.), debris will begin to accumulate on the screen surface. This accumulation will not adversely affect through-screen capacity but will hinder waste by-pass. The screen structure is of quite durable construction and will allow small tree limbs and stones to pass through without getting damaged. Compared to open-channel intakes or passive intakes, Coanda screens have a smaller capacity due to a high portion of overflow water.
Phone (USA): +1 631 839 1297