19-27: A New Technology for Ultra Low Noise and High Efficient Axial Fan for

In the industrial plants, the regulations concerning the noise emission are prescribing more and more stringent requirements. In the large cooling systems like cooling towers and air-cooled steam condensers, to comply with these regulations, the use of the so called ultra-low noise fans is mandatory. But these fans actually available on the market, despite their optimal acoustic properties, have some negative aspects in terms of efficiency, weight, and size, that determine a huge impact on the cost of the whole unit. This paper describes an innovative technology solving all the negative aspects that the last generation of the ultra-low noise fans could not solve completely.