Modulated Fan Blade Spacing for Altering Fan Noise
Publication Date: 2005-Mar-17
Publishing Venue
The IP.com Prior Art Database
Abstract
Disclosed is a method that modulates the spacing of the blades on a fan to reduce or change the characteristics of fan noise. Benefits include effecting the noise output without impacting the cost of the fan.
Modulated Fan Blade Spacing for Altering Fan Noise
Disclosed is a method that modulates the spacing of the blades on a fan to reduce or change the characteristics of fan noise. Benefits include effecting the noise output without impacting the cost of the fan.
Background
There is a need to reduce the excessive noise and unpleasant pitches that are produced by the fans used to cool a system. Current fans use spacing between the fans blades equal to 360° divided by the number of blades (see Figure 1). The following are currently used to reduce fan noise and pitch:
§ Modifying the impeller shape
§ Modifying the fan spoke shape
§ Modifying the surface that interfaces with the fan (i.e. the heat sink interface shape)
§ Modifying the specifications to allow more noise
§ Using variable speed fans
General Description
The disclosed method varies the spacing of blades on a fan in order to alter or reduce fan noise and pitch (see Figure 2). This approach is based on a NASA program that reduced helicopter noise by modulating blade spacing.
Advantages
The disclosed method reduces the amount of fan noise, and/or changes the pitch of the fan to a more pleasant tone, without impacting the cost of the fan.
Fig. 1
Fig. 2
Disclosed anonymously