UPRIGHT VACUUM WITH REDUCED NOISE
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.