Members of KNV family are able to produce high pressure difference with relatively low air-delivery rate. Fans are excellent in serving technological processes, as parts of air-handling equipment, and in any area where high pressure difference production is required. Members of the family, with 0,008-0,72 m3/s air-transmission, are able to produce 630-12.000 Pa pressure difference in case of 1,2 kg/m3 clean atmospheric air. Temperature of the delivered medium could be max. 353 K - in clutched device, while in direct-driven device it could be 333 K, but in both cases the ambient air temperature must not exceed + 40 oC (313 K). Fan efficiency - subject to operating point - is between 50 - 54 %. Fans are manufactured with block pulley armed with section steel-sheets, and bearing-bracket, engine mounting strut welded to block pulley. The blade wheel is welded, aluminic-bladed.