Cooling fan for car radiator - with fan noise reduced by lining cowl with porous plastics

摘要

The coiling fan for a car radiator is surrounded by a cowl attached to the radiator. To allow for relative movement between engine and radiator the clearance between the tips of the fan blades and the cowl is relatively large. To reduce noise, the inside of the cowel (14) is lined with a porous plastic material (15) which absorbs the noise generated by the eddies (22) generated by the tips of the blades (19). This lining reduces the level of the fan noise by 5dB to 8dB. The porous lining is provided with a layer of plastic film to prevent the ingress of dirt.