High efficiency blower housing with unequal size inlet openings
An air handler blower assembly includes a blower housing containing a centrifugal fan and a motor mounted on the blower housing and connected to the fan. The blower housing has opposite first and second air inlet openings that are coaxial with the fan, and the first inlet opening is larger than the second inlet opening. The motor is mounted on the blower housing with the motor extending axially through the first inlet opening into the blower housing and into the interior of the fan. The positioning of the motor inside the blower housing and inside the fan reduces the overall axial dimension of the blower assembly. The larger first air inlet opening reduces the losses associated with placing the motor in the first air inlet opening while keeping the second air inlet opening at a smaller size than the first air inlet opening avoids creating buffeting noise and a power/efficiency loss from occurring.
1. An air handler blower assembly comprising:
a centrifugal fan having a plurality of blades and a center axis of rotation that defines mutually perpendicular axial and radial directions relative to the blower assembly, the fan having axially opposite first and second ends;
a motor having a motor casing, the motor being operatively connected to the fan for rotation of the fan relative to the motor casing in response to operation of the motor;
a blower housing containing the fan, the blower housing having an outer wall and first and second side walls at axially opposite sides of the outer wall, the outer wall extending around the fan, the first side wall having a first air inlet opening with a first diameter dimension, the second side wall having a second air inlet opening with a second diameter dimension, and the first diameter dimension being larger than the second diameter dimension, the first and second air inlet openings being sized such that during operation of the blower assembly, air flow rate through the first air inlet opening is substantially equal to air flow rate through the second air inlet opening, the first end of the fan being adjacent the first air inlet opening and the second end of the fan being adjacent the second air inlet opening, the plurality of blades surrounding and defining a cylindrical interior volume extending from the first end of the fan to the second end of the fan;
at least one support arm operatively securing the motor to the blower housing, the at least one support arm extending into the first air inlet opening such that at least a substantial portion of the at least one support arm is within the cylindrical interior volume of the fan.
2. The blower assembly of claim 1 , further comprising:
the first side wall having a circular first inner edge that surrounds the first air inlet opening, the first inner edge having a center axis that is coaxial with the fan center axis; and,
the second side wall having a circular second inner edge that surrounds the second air inlet opening, the second inner edge having a center axis that is coaxial with the fan center axis.
3. The blower assembly of claim 1 , wherein:
the fan has a brace intermediate the first and second ends of the fan, the brace being a circular plate with a center axis that is coaxial with the fan center axis.
4. The blower assembly of claim 1 , further comprising:
the outer wall having a scroll-shaped length with opposite first and second end edges and a width with opposite first and second side edges, the outer wall length spiraling around the fan as the outer wall length extends from the first end edge to the second end edge, the outer wall first and second end edges being positioned on opposite sides of an outlet opening of the blower housing;
the first side wall being connected to the outer wall first side edge and the second side wall being connected to the outer wall second side edge with the first and second side walls being positioned on opposite sides of the outlet opening.
5. The blower assembly of claim 1 , further comprising:
the motor having an axial length and most of the motor axial length being positioned inside the blower housing between the first and second side walls.