There are a number of key factors that ensures the SuraFlow-GutterGuard system is effective in keeping debris of gutters while allowing the water to flow in.
There are two basic principles that make SuraFlow-GutterGuard so effective. The first is that it is a solid cover over the gutter through which nothing can penetrate. The second is the use of the Coanda Effect, first discovered by Romanian aerodynamicist Henri-Marie Coanda (1885-1972) in 1930 to ensure that the water is drained away by the gutter beneath.
The anodized surface of SuraFlow-GutterGuard system has very low oil/wax content and is slightly porous. This helps reduce surface tension of the water which under normal circumstances would bead, but with the SuraFlow-GutterGuard system, the water forms into a micron thick layer which adheres to the contour of the bend, flowing over the surface into the gutter below.
Larger objects such a leaves needles that are likely to have been washed down from the roof are unable to remain in suspension as the water travels around the bend, because of the thinness of the layer of water, and as such are expelled from the surface onto the floor below.
Performance
Water handling capacity is measured in litres per millimetre per metre width. In the UK it is generally accepted that existing gutter systems will handle a maximum rainfall of 75mm/hour. The SuraFlow-GutterGuard system has been tested and proved to handle 40 litres/min/m, which on a 10m roof length equates to 40mm/min (2400mm/hour), or 32 times the accepted maximum rainfall for mainland UK.