Noise-reduced vacuum appliance

Abstract

A vacuum appliance includes a motor having a rotatable shaft. An air flow generating member is connected to the shaft. The air flow generated by the rotating member generates noise having a frequency and corresponding wavelength. An air flow path receives air generated by the rotating member. The air flow path has first and second channels, the lengths of which define a predetermined difference therebetween to cancel the noise. In certain embodiments, the difference is corresponds to one-half wavelength.

1 . A vacuum appliance, comprising: 
 a motor having a rotatable shaft;    an air flow generating member connected to the shaft, the air flow generating member generating noise having a frequency and corresponding wavelength; and    an air flow path receiving air generated by the air flow generating member, the air flow path including first and second channels, each channel defining corresponding first and second lengths, the first and second lengths defining a predetermined difference therebetween to cancel the noise.    
   
   
       2 . The vacuum appliance of  claim 1 , wherein the predetermined difference between the first and second lengths corresponds to one-half wavelength.  
   
   
       3 . The vacuum appliance of  claim 1 , wherein the air flow generating member comprises a blower wheel.  
   
   
       4 . The vacuum appliance of  claim 1 , wherein the air flow generating member comprises a cooling fan.  
   
   
       5 . The vacuum appliance of  claim 1 , wherein the air flow generating member comprises a commutator of the motor.