1. A blower assembly comprising:
- a housing having a pair of side walls and an outer wall connecting the side walls, the outer wall having a cutoff portion and an outlet portion;
an outlet of the housing defined at least in part by an outlet end of the outlet portion and the cutoff portion;
a scroll portion of the outer wall connecting the cutoff portion and the outlet portion; and
the outlet portion flaring outwardly away from the cutoff portion as the outlet portion extends from the scroll portion to the outlet end of the outlet portion.
In accordance with one aspect of the current disclosure, a blower assembly is provided that includes a housing having a pair of side walls and an outer wall connecting the side walls. The outer wall has a cutoff portion and an outlet portion. The housing includes an outlet defined at least in part by an outlet end of the outlet portion and the cutoff portion. The outer wall includes a scroll portion connecting the cutoff portion and the outlet portion. The outlet portion flares outwardly away from the cutoff portion as the outlet portion extends from the scroll portion to the outlet end of the outlet portion.
- 1. A blower assembly comprising:
a housing having a pair of side walls and an outer wall connecting the side walls, the outer wall having a cutoff portion and an outlet portion; an outlet of the housing defined at least in part by an outlet end of the outlet portion and the cutoff portion; a scroll portion of the outer wall connecting the cutoff portion and the outlet portion; and the outlet portion flaring outwardly away from the cutoff portion as the outlet portion extends from the scroll portion to the outlet end of the outlet portion.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 11. A blower assembly comprising:
a fan; a motor connected to the fan; a housing having a pair of side walls and an outer wall assembly connecting the side walls; a primary wall of the outer wall assembly including a scroll portion and an outlet portion; a cutoff of the outer wall assembly; an outlet of the housing defined at least in part by the outlet portion of the primary wall and the cutoff; and an adjustable connection between the cutoff and the primary wall that permits the cutoff to be shifted toward the outlet portion to decrease the size of the housing outlet and away from the outlet portion to increase the size of the housing outlet.
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
This application claims the benefit of U.S. Provisional Application No. 62/857,061, filed Jun. 4, 2019, and U.S. Provisional Application No. 62/750,814, filed Oct. 25, 2018, which are hereby incorporated herein by reference in their entireties.
This disclosure relates to blowers and, more specifically, to blowers for air handler units.
Air handler units include forced air furnaces such as furnaces used in homes. Forced air furnaces utilize a blower that blows air across one or more heat exchangers of the furnace to heat the air. The heated air is then directed out of an outlet of the furnace and into ductwork of the associated building.
Some conventional blowers have a housing, a single or double inlet wheel fan within the housing, and a motor for driving the fan. The fan has forward inclined blades that draw air into a center of the fan in a direction parallel to an axis of rotation of the fan as the fan rotates. The fan blades direct the air radially outward against a scroll-shaped outer wall of the housing. The scroll-shaped outer wall extends from a cutoff of the blower housing to a redirecting wall extending perpendicular to a radius of the scroll-shaped outer wall. The fan pushes the air along the scroll-shaped wall until the air reaches the redirecting wall. The redirecting wall redirects airflow from a generally circumferential direction along the scroll-shaped wall to a tangential direction. This redirection is used in conventional blower to direct the air flow outward from an outlet of the blower in a direction normal to a heat exchanger of the furnace.
With reference to
With reference to
The blower 14 includes an adjustable cutoff 70 having a cutoff 72 and a slide connection 74 that permits the cutoff 72 to be adjusted in directions 78A, 78B. The blower 14 may have a cutoff angle β in the range of approximately 15 degrees to approximately 35 degrees, such as twenty-five degrees, as shown in
Further, the adjustable cutoff 70 includes lateral supports 77 for resisting deflection of the cutoff 72 in direction 79 as shown in
The fan 32 may be a fan as disclosed in U.S. Pat. No. 8,881,396, which is incorporated herein by reference. In one embodiment, the fan 32 includes end rings 80 and a solid central hub 82 as shown in
With reference to
With reference to
In the equation, RH is the radius of the outer wall 46, including the scroll portion 100, of the blower housing 30, e.g. 103, 107, 102, 109, 105, 113, 117, 106, 119, 108, RW is the radius of the wheel for that housing, and K is the trigonometric sine of the scroll development angle desired (also referred to as the scroll expansion angle or diffuser angle). The scroll development angle may be in the range of approximately 4 degrees to approximately 12 degrees, such as approximately 7.5 degrees to approximately 9.5 degrees, such as approximately 7.5 degrees. L is the angle, in radians, to the point being considered, and L ranges from zero to 2π radians. With reference to
The outer wall 46 further includes an outlet portion 112 that extends from the scroll portion end 110 to the second end 92. The outlet portion 112 has a non-scroll shape. In the embodiment shown in
The dimensions and shape of the blower housing 30 are selected according to the following considerations. For a given air handler, the flange 94 is adapted to fit within the air handler and the scroll portion 100 is configured according to the Archimedean equation approximation provided above based on the wheel fan radius. The outer wall 46 is configured so that the outlet portion 112 extends inward from the flange 94 at the largest angle 114 permitted by the interior of the air handler, such as up to 15 degrees. The larger the angle 114, the fewer eddies are formed in the airflow by converting rotational air velocity to planar velocity as well as converting velocity pressure to static pressure, which reduces turbulence in the airflow and increases efficiency, both static and sound efficiency. This also provides better airflow through the heat exchanger leading to more efficient system. The curvature of the scroll portion 100 provides smooth air flow from the cutoff 72 to the outlet portion 112. In one embodiment, the outlet portion 112 is substantially planar. The term substantially planar is intended to encompass a planar wall section as well as a planar wall section with some deviation from planar, such as vertical deviations having a height of 10% or less of the length of the outlet portion 112 in the direction of airflow. In other embodiments, the outlet portion 112 may have one or more curvatures (e.g. concave and/or convex) and/or one or more upstanding structures such as fins to direct airflow, depending on the shape and orientation of the heat exchanger in the air handler or furnace.
The blower housing 30 also has a vertical axis 120 that extends perpendicular to both the axes 116, 118. The intersection of the axes 118, 120 is located at the rotational axis 104 of the fan 32. In one embodiment, the outlet portion 112 extends away from the scroll portion end 110 to the second end 92 at an angle 115 relative to the axis 120 that is greater than 90 degrees.
The angle 114 creates a transition volume 130 within the blower housing 30 that would not exist if the outer wall 46 extended horizontally (as viewed in
With reference to
The first and second ends 90, 92 of the outer wall 46 define therebetween the outer wall opening 146 having a distance 148 thereacross that is generally fixed. The distance 148 may be in the range of 12 inches to approximately 15 inches, such as 13.67 inches. The cutoff 72 has an outer wall portion 147 (see
Where C is the housing width in inches, W is the wheel width in inches, and D is the wheel diameter in inches, for forward curved wheels.
While there have been illustrated and described particular embodiments of the present invention, those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept. For example, the blower 30 may be used in other applications such as a fan coil unit. As another example, the angle 114 may be larger than 15 degrees for some applications.