Function principle: a very small amount of compressed air escapes under high speed through a 0.5 mm narrow air gap over the entire width of the air curtain. The escaping air generates a so-called “Air Knife”, which due to the created vacuum on its sides, entrain large quantities of ambiant air. This amplifies the outgoing air many times over the supplied compressor air: 25 times air amplification for the air knives single flow and circular, and 50 times air amplification for the air knives double flow.