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US-20260126054-A1 - RETROFIT FAN ASSEMBLY

US20260126054A1US 20260126054 A1US20260126054 A1US 20260126054A1US-20260126054-A1

Abstract

A fan assembly including a housing assembly defining an inlet panel, a housing baffle, a motor mounting plate, and one or more struts, a centrifugal fan positioned within the housing assembly, and a motor operably coupling the centrifugal fan to the housing assembly. The one or more struts defining a primary airflow surface and a secondary airflow surface angle relative to one another.

Inventors

  • Vijaya Kumar Kollipara
  • Duncan Sparks

Assignees

  • GREENHECK FAN CORPORATION

Dates

Publication Date
20260507
Application Date
20251104

Claims (20)

  1. 1 . A fan assembly comprising: a) 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; b) an electric motor operably coupled to the wheel back; and c) a housing assembly supporting the electric motor and at least partially enclosing the fan wheel, the housing including: i) a plurality of struts extending from first and second ends in a lengthwise direction that is generally parallel to the longitudinal axis; ii) 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 iii) 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; d) 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.
  2. 2 . The fan assembly of claim 1 , wherein the first outlet flow surface is formed by a first panel defining a central opening through which the inlet cone extends.
  3. 3 . The fan assembly of claim 2 , wherein the central opening has a diameter that is less than a maximum outer diameter of the inlet cone.
  4. 4 . The fan assembly of claim 2 , wherein the first panel is located axially between axial first and second ends of the inlet cone.
  5. 5 . The fan assembly of claim 2 , wherein the first panel, the plurality of struts, and the bell inlet define an enclosed cavity.
  6. 6 . The fan assembly of claim 1 , wherein the plurality of struts, the first outlet flow surface, and second outlet flow surface are formed from sheet metal.
  7. 7 . The fan assembly of claim 1 , wherein the second outlet flow surface has a contour shaped to match a contour of the wheel back.
  8. 8 . The fan assembly of claim 7 , wherein the wheel back contour has a curved or conical shape.
  9. 9 . The fan assembly of claim 1 , wherein the plurality of struts defines a primary airflow surface and a secondary airflow surface angled relative to one another.
  10. 10 . The fan assembly of claim 1 , wherein the plurality of struts includes 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.
  11. 11 . The fan assembly of claim 1 , wherein the plurality of struts includes an airfoil structure including a leading edge and a trailing edge.
  12. 12 . The fan assembly of claim 1 , wherein the plurality of struts includes a plurality of serrations defined along a trailing edge.
  13. 13 . The fan assembly of claim 1 , wherein the plurality of struts includes a plurality of lateral ribs extending laterally outward from at least one of a primary airflow surface or a secondary airflow surface.
  14. 14 . The fan assembly of claim 1 , wherein 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.
  15. 15 . A fan assembly comprising: 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.
  16. 16 . The fan assembly of claim 9 , wherein 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.
  17. 17 . A fan assembly comprising: 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 the 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) a leading edge and a trailing edge that extend at oblique angles to each other; b) an airfoil shape; c) a plurality of serrations defined along a trailing edge; d) a plurality of radially or laterally extending ribs; and e) a first planar surface and a second planar surface with a transitional surface positioned therebetween.
  18. 18 . The fan assembly of claim 17 , wherein the corners of one or both of the inlet panel and the motor mounting plate are chamfered.
  19. 19 . The fan assembly of claim 17 , further including a baffle plate located between the inlet panel and the motor mounting plate, the baffle plate being secured to the plurality of struts.
  20. 20 . The fan assembly of claim 17 , wherein each of the plurality of struts, the inlet panel, and the motor mounting plate are formed from sheet metal.

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 mo