Low-noise axial-inlet fan - has foam-lined inlet duct and three=dimensional network of random rods in eddy areas between impeller blades

摘要

The low-noise fan comprises a motor-driven impeller with axial inlet in a housing with at least one inlet duct whose wall consists of a sound-absorbent material, such as open-cell polyurethane foam. The flow passages between the impeller blades are provided with a three-dimentional network of randomly arranged rods at least in the areas where eddies are generated by detachment of the boundary flow and/or in the adjacent suction area. This network may be arranged adjacent the outer periphery of the impeller. The impeller may be of the capillary type having the flow path consisting of such networks, e.g. in a foam impeller formed as a polyurethane skeleton.