Upright vacuum with reduced noise

Abstract

According to various embodiments, a method of reducing noise generated by a vacuum is described. The method comprises providing a vacuum comprising a motor including a motor shaft adapted to operate at a rotational speed of n; attaching a centripetal fan with t number of blades attached to the motor shaft; enclosing the fan between the motor and a motor housing end bracket disposed about the shaft, the motor housing end bracket defining an air input opposite an air output; wherein the variables of speed n and the number of blades t are selected so that a blade pass frequency (BPF) of the centripetal fan is greater than about 5000 Hertz, and the BPF is calculated as BPF=n*t/60. A vacuum implementing the method is also described.

1 . A method of reducing noise generated by a vacuum, the method comprising:
 providing a vacuum comprising a motor including a motor shaft adapted to operate at a rotational speed of n;   attaching a centripetal fan with t number of blades attached to the motor shaft;   enclosing the fan between the motor and a motor housing end bracket disposed about the shaft, the motor housing end bracket defining an air input opposite an air output;   wherein the variables of speed n and the number of blades t are selected so that a blade pass frequency (BPF) of the centripetal fan is greater than about 5000 Hertz, and the BPF is calculated as BPF=n*t/60.   
     
     
         2 . The method of  claim 1 , wherein the speed n is greater than 10,000 RPM. 
     
     
         3 . The method of  claim 1 , wherein the total area of the centripetal fan blade area generates greater than about 20 cubic feet per minute of airflow between the air input and the air output. 
     
     
         4 . The method of  claim 1 , wherein the centripetal fan has 30 or more blades. 
     
     
         5 . The method of  claim 1 , wherein the BPF is greater than about 6000 Hertz. 
     
     
         6 . The method of  claim 1 , wherein the BPF is greater than about 9000 Hertz. 
     
     
         7 . The method of  claim 1 , wherein the BPF is outside a human ear's irritation noise range. 
     
     
         9 . The method of  claim 1 , wherein the motor selectively operates at about 13000 RPM and about 18000 RPM. 
     
     
         10 . The method of  claim 1 , wherein the blades of the centripetal fan have a slight backward curve relative to a rotational direction of the fan. 
     
     
         11 . The method of  claim 1 , further comprising cooling components disposed in the vacuum base with the airflow exiting the air output. 
     
     
         12 . The method of  claim 1 , further comprising disposing an air exhaust in a vacuum base in the same plane as an air intake. 
     
     
         13 . The method of  claim 11 , further comprising determining the temperature of the motor; and shutting off the motor when the temperature exceeds a predetermined temperature. 
     
     
         14 . A vacuum comprising:
 a motor including a motor shaft to operate at a rotational speed of n;   a motor housing end bracket disposed about the shaft, the motor housing end bracket defining an air input opposite an air output; and   a centripetal fan with t number of blades attached to the motor shaft and enclosed between the motor and the motor housing end bracket;   wherein the variables of speed n and the number of blades t are selected so that a blade pass frequency (BPF) of the centripetal fan is greater than about 5000 Hertz, and the BPF is calculated as BPF=n*t/60.   
     
     
         15 . The vacuum of  claim 14 , wherein the speed n is greater than 10,000 RPM. 
     
     
         16 . The vacuum of  claim 14 , wherein the total area of the centripetal fan blade area generates greater than about 20 cubic feet per minute of airflow between the air input and the air output. 
     
     
         17 . The vacuum of  claim 14 , wherein the centripetal fan has 30 or more blades. 
     
     
         18 . The vacuum of  claim 14 , wherein the BPF is greater than about 6000 Hertz. 
     
     
         19 . The vacuum of  claim 14 , wherein the BPF is greater than about 9000 Hertz. 
     
     
         20 . The vacuum of  claim 14 , wherein the motor selectively operates at about 13000 RPM and about 18000 RPM. 
     
     
         21 . The vacuum of  claim 14 , wherein the blades of the centripetal fan have a slight backward curve relative to a rotational direction of the fan. 
     
     
         22 . The vacuum of  claim 14 , further comprising:
 an air exhaust disposed in a vacuum base; and   an air intake in the vacuum base in the same plane the an air exhaust.