RETROFIT FAN ASSEMBLY

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 63/716,960, filed Nov. 6, 2024, titled “RETROFIT FAN ASSEMBLY,” the disclosure of which is hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to fans used in air handling and air delivery equipment for heating, ventilation and air conditioning systems.

BACKGROUND

Centrifugal fans, including plenum fans and housed centrifugal fans, are commonly employed in Heating, Ventilation, and Air Conditioning (HVAC) systems. Plenum fans are tailored for use in plenum chambers or enclosed spaces within ductwork where air circulates, whereas housed centrifugal fans have a broader range of applications within various ventilation systems. Despite their specialized uses, both fan types commonly confront issues related to efficiency and noise generation.

Concerning static efficiency, centrifugal fans experience significant expansion losses at the fan outlet, which exceed the frictional losses caused by air resistance through friction and turbulence as air moves through the fan. These losses are exacerbated at higher air velocities, peaking at maximum velocity points. This leads to notable expansion losses as air transitions into the larger cross-sectional areas of the plenum, resulting in decreased air pressure and velocity, thereby impairing the fan's efficiency and overall performance. A static efficiency rating between 70-75% is typically considered acceptable for these fans.

Furthermore, noise generation remains a significant concern with centrifugal fans, where radial acceleration of air contributes to noise production, posing disruptive challenges in various settings. Despite ongoing efforts to improve these aspects, there is a continued demand for advancements in fan static efficiency and noise reduction in plenum fans and housed centrifugal fans.

SUMMARY

Embodiments of the present disclosure address the challenges associated with expansion losses and operational noise in fan systems by introducing a housing assembly that defines one or more physical features configured to improve airflow characteristics. Specifically, embodiments of the present concept can include a housing assembly equipped with an inlet panel, a housing baffle, a motor mounting plate, and one or more struts designed to optimize airflow within the assembly. The centrifugal fan, positioned within this assembly, can feature either an angled or curved wheel back that is complemented by a shaped panel on the motor mounting plate, specifically contoured to match this curvature, enhancing airflow efficiency and reducing turbulence.

Moreover, the housing baffle can be configured to partially encircle the outer perimeter of an inlet cone, which can be defined by the centrifugal fan extending from a central air inlet aperture to the outer perimeter, thus guiding airflow smoothly into the fan. The struts within the housing assembly can be configured with a primary and a secondary airflow surface set at precise angles to each other to further manage airflow direction and speed.

The struts can also be equipped with additional aerodynamic features such as stator blades that can extend orthogonally from the airflow surfaces, airfoil structures that can include optimized leading and trailing edges, and serrations along the trailing edges that can disrupt air patterns to reduce noise and improve flow efficiency. In some embodiments, lateral ribs can extend from the surfaces to reinforce the structure and modify the airflow, and the inclusion of planar surfaces at distinct angles introduces variability in airflow management, enabling for a customized airflow profile that can be tailored to specific operational needs.

A fan assembly can include a housing assembly comprising an inlet panel, a housing baffle, a motor mounting plate, and one or more struts; a centrifugal fan wheel positioned within the housing assembly, the centrifugal fan defining at least one of an angled or curved wheel back defining a first airflow surface; and a motor operably coupling the centrifugal fan to the housing assembly; wherein the motor mounting plate includes a panel defining a second airflow surface shaped to match the first airflow surface of the wheel back of the centrifugal fan.

In some examples, the centrifugal fan defines an inlet cone extending between a central air inlet aperture and an outer perimeter, and wherein the housing baffle includes a panel defining airflow surface configured at least partially surround the outer perimeter of the inlet cone.

In some examples, the one or more struts define a primary airflow surface and a secondary airflow surface angle relative to one another.

In some examples, the one or more struts include at least one stator blade extending orthogonally outward from at least one of a primary airflow surface or a secondary airflow surface of the one or more struts.

In some examples, the one or more struts include an airfoil structure including a leading edge and a trailing edge.

In some examples, the one or more struts include a plurality of serrations defined along a trailing edge.

In some examples, the one or more struts include a plurality of lateral ribs extending laterally outward from at least one of a primary airflow surface or a secondary airflow surface.

In some examples, the one or more struts define a first planar surface and a second planar surface with a transitional surface positioned therebetween, wherein the first planar surface and the second planar surface are positioned at distinct angles relative to one another.

A fan assembly can include a housing assembly comprising an inlet panel, a housing baffle, a motor mounting plate, and one or more struts; a centrifugal fan positioned within the housing assembly, the centrifugal fan defining an inlet cone extending between a central air inlet aperture and an outer perimeter; and a motor operably coupling the centrifugal fan to the housing assembly; wherein the housing baffle includes a panel defining airflow surface configured to at least partially surround the outer perimeter of the inlet cone.

In some examples, the centrifugal fan defines at least one of an angled or curved wheel back, and the motor mounting plate includes a shaped panel defining airflow surface shaped to match the angled or curved wheel back of the centrifugal fan.

In some examples, the one or more struts define a primary airflow surface and a secondary airflow surface angle relative to one another.

In some examples, the one or more struts include at least one stator blade extending orthogonally outward from at least one of a primary airflow surface or a secondary airflow surface of the one or more struts.

In some examples, the one or more struts include an airfoil structure including a leading edge and a trailing edge.

In some examples, the one or more struts include a plurality of serrations defined along a trailing edge.

In some examples, the one or more struts include a plurality of lateral ribs extending laterally outward from at least one of the primary airflow surface or the secondary airflow surface.

In some examples, the one or more struts define a first planar surface and a second planar surface with a transitional surface positioned therebetween, wherein the first planar surface and the second planar surface are positioned at distinct angles relative to one another.

A fan assembly can include a housing assembly comprising an inlet panel, a motor mounting plate having chamfered corners, and one or more struts operably coupled between the inlet panel and the chamfered corners of the motor mounting plate; a centrifugal fan positioned within the housing assembly; and a motor operably coupling the centrifugal fan to the housing assembly; wherein the one or more struts each define a primary airflow surface and a secondary airflow surface angled obliquely relative to one another.

In some examples, the one or more struts further include at least one stator blade extending orthogonally outward from at least one of the primary airflow surface or the secondary airflow surface of the one or more struts.

In some examples, the one or more struts further include an airfoil structure including a leading edge and a trailing edge.

In some examples, the one or more struts include a plurality of serrations defined along the trailing edge.

In some examples, the one or more struts include a plurality of lateral ribs extending laterally outward from at least one of the primary airflow surface or the secondary airflow surface.

In some examples, the one or more struts define a first planar surface and a second planar surface with a transitional surface positioned therebetween, wherein the first planar surface and the second planar surface are positioned at distinct angles relative to one another.

In some examples, the centrifugal fan defines at least one of an angled or curved wheel back, and the motor mounting plate includes a shaped panel defining airflow surface shaped to match the angled or curved wheel back of the centrifugal fan.

In some examples, the centrifugal fan defines an inlet cone extending between a central air inlet aperture and an outer perimeter, and wherein the housing assembly further includes a housing baffle defining airflow surface configured to at least partially surround the outer perimeter of the inlet cone.

A fan assembly can include a fan wheel including a plurality of fan blades extending between an inlet cone and a wheel back, the fan wheel extending along a longitudinal axis; an electric motor operably coupled to the wheel back; and a housing assembly supporting the electric motor and at least partially enclosing the fan wheel, the housing including: a plurality of struts extending from first and second ends in a lengthwise direction that is generally parallel to the longitudinal axis; a front wall structure supported by the plurality of struts proximate the first ends, the front wall structure defining a bell inlet extending to the inlet cone and defining a first outlet flow surface extending from a location proximate an outer perimeter of the inlet cone to the plurality of struts; and a rear wall structure supported by the plurality of struts proximate the second ends, the rear wall structure operably supporting the electric motor and defining a second outlet flow surface extending from a location proximate an outer perimeter of the wheel back to the plurality of struts, wherein the second outlet flow surface extends at an oblique angle to the first outlet flow surface; wherein the plurality of struts, the first outlet flow surface, and the second outlet flow surface define a plurality of air outlets extending from the fan blades.

In some examples, the first outlet flow surface is formed by a first panel defining a central opening through which the inlet cone extends.

In some examples, the central opening has a diameter that is less than a maximum outer diameter of the inlet cone.

In some examples, the first panel is located axially between axial first and second ends of the inlet cone.

In some examples, the first panel, the plurality of struts, and the bell inlet define an enclosed cavity.

In some examples, the plurality of struts, the first outlet flow surface, and the second outlet flow surface are formed from sheet metal.

In some examples, the second outlet flow surface has a contour shaped to match a contour of the wheel back.

In some examples, the wheel back contour has a curved or conical shape.

In some examples, the plurality of struts define a primary airflow surface and a secondary airflow surface angled relative to one another.

In some examples, the plurality of struts include at least one stator blade extending orthogonally outward from at least one of the primary airflow surface or the secondary airflow surface of the one or more struts.

In some examples, the plurality of struts include an airfoil structure including a leading edge and a trailing edge.

In some examples, the plurality of struts includes a plurality of serrations defined along the trailing edge.

In some examples, the plurality of struts includes a plurality of lateral ribs extending laterally outward from at least one of the primary airflow surface or the secondary airflow surface.

In some examples, the plurality of struts defines a first planar surface and a second planar surface with a transitional surface positioned therebetween, wherein the first planar surface and the second planar surface are positioned at distinct angles relative to one another.

A fan assembly can include a housing assembly comprising an inlet panel, a housing baffle, a motor mounting plate, and one or more struts; a centrifugal fan positioned within the housing assembly, the centrifugal fan defining an inlet cone extending between a central air inlet aperture and an outer perimeter; and a motor operably coupling the centrifugal fan to the housing assembly; wherein the housing baffle includes a panel defining an airflow surface configured to at least partially surround the outer perimeter of the inlet cone.

In some examples, the centrifugal fan defines at least one of an angled or curved wheel back, and the motor mounting plate includes a shaped panel defining airflow surface shaped to match the angled or curved wheel back of the centrifugal fan.

A fan assembly can include a housing assembly comprising an inlet panel, a motor mounting plate, and a plurality of struts extending between corners of the inlet panel and the motor mounting plate; a centrifugal fan positioned between the inlet panel and motor mounting plate; and a motor operably coupled to the centrifugal fan and supported by the motor mounting plate; wherein the plurality of struts includes one or more of: a leading edge and a trailing edge that extend at oblique angles to each other; an airfoil shape; a plurality of serrations defined along the trailing edge; a plurality of radially or laterally extending ribs; and a first planar surface and a second planar surface with a transitional surface positioned therebetween.

In some examples, the corners of one or both of the inlet panel and the motor mounting plate are chamfered.

In some examples, a baffle plate is located between the inlet panel and the motor mounting plate, the baffle plate being secured to the plurality of struts.

In some examples, each of the plurality of struts, the inlet panel, and the motor mounting plate are formed from sheet metal.

A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:

FIG. 1 is a perspective view depicting a fan assembly, in accordance with an embodiment of the disclosure.

FIG. 2 is an exploded, perspective view depicting the fan assembly of FIG. 1.

FIG. 3 is a profile view depicting a centrifugal fan, in accordance with an embodiment of the disclosure.

FIG. 4 is a first perspective, cross-sectional view depicting the centrifugal fan of FIG. 3.

FIG. 5 is a second perspective, cross-sectional view depicting the centrifugal fan of FIG. 3.

FIG. 6 is a first, partial cross-sectional view depicting the centrifugal fan of FIG. 3.

FIG. 7 is a second, partial cross-sectional view depicting the centrifugal fan of FIG. 3.

FIG. 8 is an exploded, perspective view depicting a centrifugal fan and motor, in accordance with an embodiment of the disclosure.

FIG. 9 is a perspective view depicting the assembled centrifugal fan and motor of FIG. 8.

FIG. 10 is a perspective view depicting an inlet panel, in accordance with an embodiment of the disclosure.

FIG. 11 is a first profile view depicting the inlet panel of FIG. 10.

FIG. 12 is a plan view depicting the inlet panel of FIG. 10.

FIG. 13 is a second profile view depicting the inlet panel of FIG. 10.

FIG. 14 is a perspective view depicting a housing baffle, in accordance with an embodiment of the disclosure.

FIG. 15 is a first profile view depicting the housing baffle of FIG. 14.

FIG. 16 is a plan view depicting the housing baffle of FIG. 14.

FIG. 17 is a second profile view depicting the housing baffle of FIG. 14.

FIG. 18 is a perspective view depicting a motor mounting plate, in accordance with an embodiment of the disclosure.

FIG. 19 is a first profile view depicting the motor mounting plate of FIG. 18.

FIG. 20 is a plan view depicting the motor mounting plate of FIG. 18.

FIG. 21 is a second profile view depicting the motor mounting plate of FIG. 18.

FIG. 22 is a perspective, cross-sectional view depicting a fan assembly, in accordance with an embodiment of the disclosure.

FIG. 22A is a profile, cross-sectional view depicting the fan assembly of FIG. 22.

FIG. 22B is a profile, cross-sectional view depicting the fan assembly of FIG. 22, illustrating a diffusion outlet control area.

FIG. 23 is a first profile view depicting a strut, in accordance with an embodiment of the disclosure.

FIG. 24 is a perspective view depicting the strut of FIG. 23.

FIG. 25 is an end view depicting the strut of FIG. 23.

FIG. 26 is a second profile view depicting the strut of FIG. 23.

FIG. 27 is a cross-sectional, plan view depicting a fan assembly, in accordance with an embodiment of the disclosure.

FIG. 28 is a partial, perspective, cross-sectional view depicting a strut of the fan assembly of FIG. 27.

FIG. 29 is a perspective view depicting a strut including one or more stators, in accordance with an embodiment of the disclosure.

FIG. 30 is a perspective view depicting the strut of FIG. 29.

FIG. 31 is an end view depicting the strut of FIG. 29.

FIG. 32 is a second profile view depicting the strut of FIG. 29.

FIG. 33 is a perspective view depicting a fan assembly including one or more struts like that depicted in FIGS. 29-30.

FIG. 34 is a perspective view depicting a strut defining an airfoil, in accordance with an embodiment of the disclosure.

FIG. 35 is a perspective view depicting the strut of FIG. 34.

FIG. 36 is an end view depicting the strut of FIG. 34.

FIG. 37 is a second profile view depicting the strut of FIG. 34.

FIG. 38 is a perspective view depicting a fan assembly including one or more struts like that depicted in FIGS. 34-37.

FIG. 39 is a perspective view depicting a strut defining serrations, in accordance with an embodiment of the disclosure.

FIG. 40 is a perspective view depicting the strut of FIG. 39.

FIG. 41 is an end view depicting the strut of FIG. 39.

FIG. 42 is a second profile view depicting the strut of FIG. 39.

FIG. 43 is a perspective view depicting a fan assembly including one or more struts like that depicted in FIGS. 39-42.

FIG. 44 is a perspective view depicting a strut defining one or more ribs, in accordance with an embodiment of the disclosure.

FIG. 45 is a perspective view depicting the strut of FIG. 44.

FIG. 46 is an end view depicting the strut of FIG. 44.

FIG. 47 is a second profile view depicting the strut of FIG. 44.

FIG. 48 is a perspective view depicting a fan assembly including one or more struts like that depicted in FIGS. 44-47.

FIG. 49 is a perspective view depicting a strut defining multiple planar surfaces mounted at distinct angles relative to one another, in accordance with an embodiment of the disclosure.

FIG. 50 is a perspective view depicting the strut of FIG. 49.

FIG. 51 is an end view depicting the strut of FIG. 49.

FIG. 52 is a second profile view depicting the strut of FIG. 49.

FIG. 53 is a perspective view depicting a fan assembly including one or more struts like that depicted in FIGS. 49-53.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Fan Assembly

Referring to FIGS. 1-2, a fan assembly 100 is depicted according to an embodiment of the disclosure. The fan assembly 100 can be configured to move air in building HVAC systems. As shown, the fan assembly 100 can include a centrifugal fan 102 housed within a housing assembly 104. The centrifugal fan 102 can comprise multiple blades which, upon rotation relative to the housing assembly 104, can facilitate airflow entering axially through a central opening at the front of the housing assembly 104 and exiting radially outward through one or more sidewall openings defined by the housing assembly 104. Alternative embodiments may incorporate different fan wheel configurations, such as mixed flow fan wheels. A compact, energy-efficient electric motor 106 can power rotation of the centrifugal fan 102.

Embodiments of the present disclosure incorporate a distinct three-dimensional design of the housing assembly 104, enhancing airflow efficiency through the fan assembly 100. In particular, the housing assembly 104 can include an inlet panel 108, a housing baffle 110, a motor mounting plate 112, and multiple struts 114A-D. With continued reference to FIG. one, the dimensions of the fan assembly 100 may be defined in this disclosure in terms of width (W) along a lateral x-axis, length (L) along a longitudinal y-axis, and height or depth (D) along a vertical z-axis, with these axes being orthogonal to one another and forming a three-dimensional coordinate system.

In certain applications, the fan assembly 100 may function independently, replacing traditional plenum or housed centrifugal fans. Alternatively, multiple fan assemblies 100 can be configured in an array to collectively manage large air volumes, which can replace a single large air mover in existing HVAC or cooling systems, offering advantages in noise reduction and a more compact, lighter design.

Centrifugal Fan

With additional reference to FIGS. 3-7, additional views of the centrifugal fan 102 are depicted in accordance with an embodiment of the disclosure. As depicted, the centrifugal fan 102 can include a wheel cone 116, a wheel back 118 and a plurality of blades 120.

The wheel cone 116 can include a first airflow surface 122, which can be in the form of a major surface representing one side of the wheel cone 116. In embodiments, the first airflow surface 122 can define the interior of a cone or bell structure. For example, in some embodiments, the first airflow surface 122 can generally have the shape of a curved funnel-shaped conical surface extending between a central air inlet aperture 117 and an air outlet or trailing edge positioned along an outer perimeter 121 of the wheel cone 116. The outer perimeter 121 can be defined by a diameter D1 (as depicted in FIG. 3).

The wheel back 118 can define a second airflow surface 124, which can be in the form of a major surface representing one side of the wheel back 118. In some embodiments, the second airflow surface 124 can be curved, dome-shaped, conical, or frusto-conical in shape, such that the second airflow surface 124 represents an outside of curve or cone shape, in which an axis of the second airflow surface 124 extends along the z-axis. For example, in some embodiments, the second airflow surface 124 can form an angle of between about 0° and about 60° with either of the x- or y-axes. In another embodiment, the second airflow surface 124 can have a curved or truncated dome-shaped profile. In such embodiments, the first airflow surface 122 and the second airflow surface 124 can serve to reduce the abrupt change in direction otherwise required of airflow entering into the centrifugal fan 102, thereby reducing turbulence tending to occur near a center 126 of the wheel back 118. In other embodiments, the second airflow surface can be substantially planar.

In some embodiments, the plurality of blades 120 can operably couple the wheel cone 116 to the wheel back 118, such that the wheel cone 116 is spaced apart from the wheel back 118. In embodiments, a corresponding plurality of air channels 128 can be defined between the plurality of blades 120 (as depicted in FIG. 5). For example, the first airflow surface 122, the second airflow surface 124, and a series of adjacent blades 120 can cooperate to define a plurality of air channels 128.

In embodiments, each of the blades 120 can include an inlet or leading edge 130 positioned in proximity to the central air inlet aperture 117, and an outlet or trailing edge 132 positioned in proximity to the outer perimeter 121. A first area 136 defined by each air channel 128 in proximity to the leading edge 130 can have a smaller cross-sectional area than a second area 138 defined by the air channels 128 in proximity to the outer perimeter 121.

Such a configuration allows for a gradual increase in cross-sectional area as the air channels 128 progress towards the outer edge of the blades. By reducing the cross-sectional area at the leading edge (e.g., first area 136) and gradually increasing it towards the outer perimeter (e.g., second area 138), the velocity of the air passing through the air channels 128 is gradually reduced, resulting in increased pressure and mitigating the efficiency losses typically associated with centrifugal fans. Modification of the cross-sectional areas in this manner serves to improve the overall efficiency and performance of the fan assembly 100, while also minimizing noise generation.

As depicted in FIGS. 6-7, each of the blades 120 can have a complex three dimensional shape, exhibiting a compound curve in both of a first plane parallel to the x- and y-axes (as depicted in FIG. 6), an in a second plane parallel to the x- and z-axes (as depicted in FIG. 7). Specifically, in some embodiments the trailing edge 132 of each blade 120 can be curved to increase the cross-sectional area of the second area 138 in proximity to the outer perimeter 121. In the example shown, the trailing edge 132 is provided with a concave asymmetric curved shape, which can generally serve to reduce expansion losses. In some embodiments, the asymmetrical trailing edge 132 curvature aids in the separation of flow at the wheel back 118 and the uniform distribution of pressure across the blade span (e.g., from the wheel cone 116 to the wheel back 118), resulting in a quieter, more energy efficient flow of air through the centrifugal fan 102.

Electric Motor

With additional reference to FIGS. 8-9, in some embodiments, wheel back 118 of the centrifugal fan 102 can define an interior region 140 for mounting of the electric motor 106. As depicted, the wheel back 118 can include a substantially planar central portion 142 positioned substantially orthogonal to the z-axis, surrounded by a frusto-conical, curved or dome-shaped profile outer portion to define the interior region 140. To facilitate connection of the electric motor 106 to the centrifugal fan 102, in some embodiments, the wheel back 118 can define a plurality of apertures arranged in a pattern (e.g., circular pattern, etc.), configured to receive a spacer block 144 and corresponding plurality of fasteners to secure the electric motor 106 to the centrifugal fan 102.

The electric motor 106 can include a stator assembly 146 and a rotor assembly 148, supported by a motor housing 150. When the electric motor 106 is energized, the stator assembly 146 causes the rotor assembly 148 to rotate. The rotor assembly 148, which is operably coupled to the wheel back 118, in turn causes the centrifugal fan 102 to rotate. In the example shown, the electric motor 106 is configured as an “axial flux motor,” which may also be referred to as an “axial gap motor” or “pancake motor.” With such a motor, the stator assembly 146 and the rotor assembly 148 are separated by an axially gap extending parallel to the axis of rotation, which results in a magnetic flux being generated substantially parallel to the axis of rotation.

Housing

The housing assembly 104 can include an inlet panel 108, a housing baffle 110, a motor mounting plate 112, and multiple struts 114A-D, the contours of which can be designed to improve airflow characteristics through the fan assembly 100, particularly enhancing air flow dynamics and efficiency as air disengages from the blades of the centrifugal fan 102.

Inlet Panel

The inlet panel 108 comprises sides 152A-D, which frame a contoured panel 154 defining an inlet cone 156 (e.g., forming a bell inlet structure) configured to be positioned adjacent to the wheel cone 116 of the fan wheel 102. As depicted, the sides 152A-D can be oriented substantially orthogonal to the contoured panel 154 and can include one or more tabs 158 for operable coupling to other portions of the housing assembly 104 (e.g., struts 114 A-D). Additionally, in some embodiments, the contoured panel 154 can define one or more cutouts 160, which can serve as a grip or handle for manipulation of the housing assembly.

Housing Baffle

The housing baffle 110 comprises orthogonally oriented sides 162A-D, with each side terminating in a chamfered corner 164A-D. As depicted, the chamfered corners 164A-D can be cut at an angle A1 (e.g., other than) 45° with respect to an adjacent side of the housing baffle 110, resulting in asymmetric chamfers that are closer to a first side than a second side, with internal angles measuring A2 and A3, respectively. In one embodiment, A1 can be about 55°, A2 can be about 125°, and A3 can be about 145°, although other angles are also contemplated. A panel 166, framed by the sides 162A-D and chamfered corner 164A-D, can be oriented substantially orthogonal to sides 162A-D and chamfered corner 164A-D, and can feature a central opening 168, configured positioned in close proximity to the outer perimeter 121 of the wheel cone 116.

As further depicted in FIG. 22, the housing baffle 110 can be configured to aid in directing airflow tangentially outward from the fan wheel 102 and away from the housing assembly 104. Specifically, the housing baffle 110 can facilitate the creation of a smooth surface (e.g., between panel 166 and first airflow surface 122 of the fan wheel 102) serving to isolate in area located rear of the inlet panel—opposite the inlet cone 156—from turbulence and non-contributory airflows, thereby enhancing the smooth passage of air through the housing assembly 104. For the purposes of illustration, the panel 166 is shown as being transparent in FIG. 22 such that aspects of the first airflow surface 122 can be more easily seen. However, as most easily viewable at FIG. 22A, the panel 166 is positioned above the lowermost shown portion of the fan wheel such that the airflow surface 122 is located between the panel 166 and the panel 176. In one aspect, the diameter of the opening 168 formed by the panel 166 is less than a maximum outer diameter of the fan wheel 102 which, in the example shown, is the maximum outer diameter of the inlet cone 156. With reference to FIG. 22B it can be seen that the surfaces defined by the panels 166, 176 act as an extension to the surfaces 122, 124 defined by the fan wheel 102 and collectively operate to provide a diffusion control outlet area 190 extending to the openings defined between the struts 114 that provides for efficiency gains in comparison to construction where no such guiding features are provided.

Motor Mounting Plate

The motor mounting plate 112 comprises orthogonally oriented sides 172A-D, each side terminating in a chamfered corner 174A-D. As depicted, the chamfered corner 174A-D can be cut at an angle A1 (e.g., other than) 45° with respect to an adjacent side of the housing baffle 110, resulting in asymmetric chamfers that are closer to a first side than a second side, with internal angles measuring A2 and A3, respectively. In one embodiment, A1 can be about 55°, A2 can be about 125°, and A3 can be about 145°, although other angles are also contemplated. A shaped panel 176, framed by the sides 172A-D and chamfered corner 174A-D, can be oriented substantially orthogonal to sides 172A-D and chamfered corner 174A-D, and can feature a motor mount 178 configured to serve as a coupling location for the motor housing 150 of the electric motor 106.

As further depicted in FIG. 22, the motor mounting plate 112 can be configured to facilitate the direction of airflow tangentially outward from the fan wheel 102 and away from the housing assembly 104. In some embodiments, the contour of shaped panel 176 can be shaped to extend the second airflow surface 124 of the wheel back 118 along a nearly continuous smooth surface. In particular, the outer perimeter 121 of the rotating wheel back 118 can align with the stationary shaped panel 176 to create a continuous surface that follows a specific angle, curve, or gradient. Additionally, the motor mounting plate 112 may incorporate an annular groove 180 designed to accommodate a circumferential projection or lip 181 positioned along the outer perimeter 121 of the wheel back 118, further enhancing the efficient and smooth flow of air through the housing assembly 104 while also reducing undesirable air recirculation. The reverse configuration is also possible in which the panel 176 is provided with a circumferential or annular protrusion received by a groove defined in the wheel back 118. Further, multiple grooves and lips or projections may be provided.

Struts

With additional reference to FIGS. 23-28, each of the struts 114 can be configured to mount between the inlet panel 108, a housing baffle 110, a motor mounting plate 112, with each of the struts 114 serving as a structural member, supporting the inlet panel 108 and housing baffle 110 in proximity to a first end 183, and the motor mounting plate 112 in proximity to a second end 114, with the centrifugal fan 102 generally positioned between the first end 183 and the second end 184. As depicted, each of the struts 114 can include multiple planes positioned at an angle (e.g., A3) relative to one another. For example, each strut 114 can include a first panel 186 defining a primary airflow surface 187, and a second panel 188 defining a secondary airflow surface 189, wherein the first panel 186 and the second panel 188 generally serve to provide a structural connection between the first and 183 and the second end 184, as well as generally guide a flow of air exiting the centrifugal fan 102.

In embodiments, the primary airflow surface 187 can have a first width S1, and the secondary airflow surface 189 have a second width S2. In some embodiments, first width S1 can be larger than second with S2 by a multiple of at least four. Further, as depicted, in some embodiments, the primary and secondary airflow surfaces 187, 189 can be angled relative to one another at angle A3, which in some embodiments can be in a range of about 100° to about 170°. For example, in one embodiment, A3 can be about 145°, although other angles are also contemplated. In some embodiments, a curled edge or folded lip along one edge of the strut can serve to increase the structural integrity of the strut 114.

As best shown in FIGS. 23-26, in some embodiments, each of the struts 114 can include a plurality of mounting tabs, facilitating connection to the inlet panel 108, housing baffle 110, and motor mounting plate 112. For example, in one embodiment, the first panel 186 can define a first tab 191 and a second tab 192. The second panel 188 can define a third tab 193. A fourth tab 194 can extend substantially orthogonal to the first panel 186. Other mounting configurations are also contemplated.

Stator Blades

Referring to FIGS. 29-33, in one embodiment, one or more struts 114 may incorporate one or more stator blades, for example, in the form of fins extending outwardly from at least one of the first panel 186 or second panel 188. As depicted, one embodiment features a plurality of first stator blades 195A-C projecting orthogonally inward from the primary airflow surface 187, and a plurality of second stator blades 196A-C projecting orthogonally outward from the first panel 186. Specifically, this embodiment includes three first stator blades 195 and three second stator blades 196. Alternative embodiments may feature varying numbers of stator blades, with configurations that include blades positioned solely on an inner or outer surface of the first panel 186 or the second panel 188. Additionally, in some embodiments, stator blades may be affixed to both the first and second panels 188, with a continuous stator blade spanning across both panels. These stator blades may be designed as thin, rigid or semi-rigid fins, potentially featuring a curved arc or angle. The arrangement of these fins may be configured to enhance desirable airflow characteristics as air moves through the fan assembly 100.

Airfoil

Referring to FIGS. 34-38, in one embodiment, one or more struts 114 can include or define an airfoil surface, which in some embodiments can be structured as a thin, rigid or semi-rigid sheet, configured to either partially or completely wrap around the first panel 186 or the second panel 188. In some embodiments, the airfoil structure 197 can feature a leading edge 198 and a trailing edge 199, though the specific shapes and dimensions can vary. The airfoil structure 197 can be operatively linked to both the first panel 186 and/or the second panel 188 and can be configured to either subtly modify or significantly enhance desirable airflow characteristics, depending on the specific requirements of the application.

Serrations

Referring to FIGS. 39-43, in one embodiment, one or more struts 114 may define a trailing edge 175 on the first panel 186, which can include a plurality of serrations 177. As depicted, the serrations 177 can be configured as a series of grooves forming a wavelike pattern cut into the trailing edge 175 of the first panel 186. The serrations 177 can serve to manipulate airflow characteristics by disrupting or smoothing the air flow as required by specific aerodynamic needs. In alternative embodiments, the serrations 177 can be positioned on the second panel 188, or other areas of the first panel 186 (e.g., in addition to or besides the trailing edge 175). Embodiments including serrations 177 enable for flexible adaptations in airflow management across different parts of the fan assembly, potentially enhancing noise reduction, vibration control, or overall airflow efficiency depending on their placement and design.

Radial Ribs

Referring to FIGS. 44-48, in one embodiment, one or more struts 114 of the fan assembly 100 can include a first panel 186 that defines a plurality of radial ribs 179. As depicted, the radial ribs 179 can be characterized as a series of undulations formed into an otherwise planar surface of the first panel 186, for example by stamping in sheet metal. The radial ribs 179 can extend radially to the trailing edge 199 of the first panel, enhancing structural integrity and modifying airflow characteristics by adding rigidity and altering air turbulence patterns across the panel surface. In alternative embodiments, the radial ribs 179 could also be positioned on the second panel 188, or various other areas of the first panel 186 aside from the trailing edge 175. Embodiments including radial ribs enable tailored aerodynamic properties and mechanical support, depending on the specific application and performance requirements of the fan assembly.

Variable Pitch

Referring to FIGS. 49-53, in one embodiment, one or more struts 114 of the fan assembly 100 are designed such that at least one of the first panel 186 and/or the second panel 188 includes multiple surfaces positioned at different planar angles, thereby creating a customized airflow profile tailored to specific performance requirements. As depicted, the first panel 186 defines a first planar surface 201 and a second planar surface 202, each oriented at a distinct angle relative to the other, with a transitional surface 203 connecting the first and second planar surfaces 201, 202. Similarly, the second panel 188 includes a first planar surface 204 and a second planar surface 205, each set at different angles, with a transitional surface 206 linking the two surfaces. As depicted in FIG. 53, in some embodiments, the first planar surfaces 201, 204 can be positioned adjacent to the inlet panel 108 and housing baffle 110, while the second planar surfaces 202, 205 can be positioned adjacent to the centrifugal fan 102, thereby serving as airflow surfaces to manage air as it flows through the fan assembly 100, thus improving operational efficiency and reducing energy consumption. Embodiments having struts 114 including variably angled surfaces can aid in manipulation of airflow dynamics to enhance airflow efficiency and performance of the fan assembly 100.

It should be noted that the various embodiments described, including the blades of FIGS. 29-33, the airfoil of FIGS. 34-38, the serrations of FIGS. 39-43, the radial ribs of FIGS. 44-48, and the variable pitch surfaces of FIGS. 49-53, are not mutually exclusive and can be integrated within a single strut assembly or distributed across multiple struts within the fan assembly 100. This integration allows for the combination of these different features to achieve a synergistic effect, enhancing the overall airflow characteristics tailored to specific needs. By incorporating one or more of these features together, such as combining the aerodynamic efficiency of airfoils with the turbulence-modulating properties of serrations or the structural support of radial ribs, the fan assembly can be optimized for enhanced airflow management, improved energy efficiency, and reduced noise levels, thereby providing a customizable solution adaptable to varying operational conditions and performance requirements.

Having described the preferred aspects and implementations of the present disclosure, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.

Materials

The disclosed retrofit fan assembly designs are not limited to any particular materials or manufacturing methods. The housing components, including the inlet panel, housing baffle, struts, and motor mounting plate described in the application may be constructed from various suitable materials depending on the specific application requirements, cost considerations, and performance specifications. For example, these components may be fabricated from sheet metal materials such as steel, aluminum, or galvanized steel, which can be formed through conventional manufacturing processes including stamping, deep drawing, roll forming, or brake forming. Alternatively, these housing components may be constructed from engineering plastics such as polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), or glass-filled nylon, which can be manufactured through injection molding, thermoforming, or other plastic forming processes. Common materials used in the construction of fan housings include various metals (steel, aluminum, stainless steel, and galvanized steel), thermoplastics (polypropylene, ABS, polycarbonate, and polyethylene), thermoset plastics (fiberglass reinforced plastics), and composite materials.

For the centrifugal fan wheel components described in the application, including the wheel cone, wheel back, and blades, suitable materials may include aluminum alloys, steel, engineering plastics such as glass-filled nylon or polycarbonate, or composite materials like carbon fiber reinforced plastics. Additionally, some of the housing components could be integrally formed to reduce part count and assembly complexity. For example, the struts described in the application could be formed as integral extensions of the inlet panel or motor mounting plate and subsequently folded, bent, or formed into their final operational positions shown in the drawings, eliminating the need for separate fastening operations.