Split blade radial fan

• US 6,435,828 B1
• Filed: 01/12/2001
• Issued: 08/20/2002
• Est. Priority Date: 01/12/2001
• Status: Expired due to Fees

• Current Assignee: Emerson Electric Company
• Original Assignee: Emerson Electric Company
• Inventors: Bostwick, Peter K.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): NGUYEN, NINH H
• Application Number:
  US09/759,966
• Publication Number:
  US 20020094275A1
• Time in Patent Office: 585 Days
• Field of Search: 416/183, 416/185, 416/189, 416/175, 416/203, 416/228
• US Class Current: 416/175
• CPC Class Codes: F04D 29/281 for fans or blowers
• CPC Class Codes: F04D 29/30 Vanes
• CPC Class Codes: H02K 9/06 with fans or impellers driven by the machine shaft

Abstract

A fan has a plurality of blades that are each configured to induce radial-flow adjacent the trailing edge of the blade while also being configured to induce both radial-flow and axial-flow near the base end of the blade. This is achieved by splitting each of the blades into two sections and orienting the chord-line of the blades near the hub of the fan at angle relative to the axis of the hub while maintaining the chord-line of the blades parallel to the axis near the trailing edges of the blades. This results in an increased ability of the fan to draw air in axially as compared to conventional radial-flow fans. The fan of the preferred embodiment also makes use of an annular ring joining the trailing edges of the blades. The ring has axially opposite sides that taper toward one another as the ring extends radially inward and acts as a diverter to channel air to axially opposite sides of an annular obstruction in the flow path of air being exhausted from the fan, thereby further increasing the fan'"'"'s efficiency.

Claims

1. A fan comprising:

a center hub having a center axis and a peripheral surface, the center axis defining axial and radial directions;

a plurality of blades configured and adapted to draw air radially outward from the center axis by revolving with the center hub about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being attached to the hub and each of the blades having an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis, each of the blades having a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, cross-sections of the first section of each of the blades have chord-lines oriented parallel to the center axis, cross-sections of the second section of each of the blades have chord-lines oriented at an angle relative to the center axis, and the angle of the chord-lines of the second section cross-sections of each of the blades increases with increasing radial distance of the cross-section from the center axis; and

,

the fan has a plurality of voids between adjacent pairs of the blades that extend axially through the fan.

2. The fan of claim 1, wherein:

substantially all of the cross-sections of each of the blades have equal axial widths.

3. The fan of claim 1, wherein:

each of the cross-sections of the first section of each of the blades is symmetric about its chord-line.

4. The fan of claim 3 wherein:

each of the cross-sections of the first section of each of the blades is substantially rectangular.

5. The fan of claim 1, wherein:

the chord-line of the cross-section of each of the blades located at the base end of each of the blades is parallel to the center axis.

6. The fan of claim 1, wherein:

the first section of each of the blades connects with the second section thereof and the cross-sections of the first section and second section are different at their connection.

20. The fan of claim 1,9 wherein:

a portion of each of the blade first sections between the distal end of the blade axial-flow portion and the trailing edge of each of the blades extends axially rearward of all portions of the blade between the base end of the blade and the distal end of the blade axial-flow portion.

7. A fan comprising:

a center hub having a center axis and a peripheral surface, the center axis defining axial and radial directions;

a plurality of blades configured and adapted to draw air radially outward from the center axis by revolving with the center hub about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being attached to the hub and each of the blades having an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis, each of the blades having a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, cross sections of the first section of each of the blades have chord-lines oriented parallel to the center axis, cross-sections of the second section of each of the blades have chord-lines oriented at an angle relative to the center axis, and the angle of the chord-lines of the second section cross-sections of each of the blades increases with increasing radial distance of the cross-section from the center axis; and

,

the blades and the hub are one monolithic piece.

8. A fan comprising:

a center hub having a center axis and a peripheral surface, the center axis defining axial and radial directions;

a plurality of blades configured and adapted to draw air radially outward from the center axis by revolving with the center hub about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being attached to the hub and each of the blades having an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis, each of the blades having a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, cross-sections of the first section of each of the blades have chord-lines oriented parallel to the center axis, cross-sections of the second section of each of the blades have chord-lines oriented at an angle relative to the center axis, and the angle of the chord-lines of the second section cross-sections of each of the blades increases with increasing radial distance of the cross-section from the center axis; and

,

each of the cross-sections of the second section of each of the blades consist of first and second portions, the first portion having opposite straight parallel sides and the second portion having opposite straight parallel sides.

9. The fan of claim 8 wherein:

the opposite parallel sides of the first portion of each of the cross-sections of the second section of each of the blades are parallel to the center axis.

10. A fan comprising:

a center hub having a center axis and a peripheral surface, the center axis defining axial and radial directions;

a plurality of blades configured and adapted to draw air radially outward from the center axis by revolving with the center hub about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being attached to the hub and each of the blades having an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis, each of the blades having a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, cross-sections of the first section of each of the blades have chord-lines oriented parallel to the center axis, cross-sections of the second section of each of the blades have chord-lines oriented at an angle relative to the center axis, and the angle of the chord-lines of the second section cross-sections of each of the blades increases with increasing radial distance of the cross-section from the center axis; and

,

a ring extending around the hub interconnecting the trailing edges of the blades.

11. The fan of claim 10, wherein:

the ring has axially opposite sides that taper toward each other as the ring extends radially inward.

12. A fan comprising:

a center hub having a center axis and a peripheral surface, the center axis defining axial and radial directions;

a plurality of blades configured and adapted to draw air radially outward from the center axis by revolving with the center hub about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being attached to the hub;

a ring extending around the hub that interconnects the trailing edges of the blades; and

,

each of the blades has an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis and each of the blades has a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, each of the cross-sections of the first section of each of the blades have chord-lines oriented parallel to the center axis, cross-sections of the second section of each of the blades have chord-lines oriented at an angle to the center axis, and the angle of the chord-lines of the cross-sections of the second section of each of the blades increases with increasing radial spacing of the cross-section from the center axis, substantially all of the cross-sections of each of the blades having equal axial width.

13. The fan of claim 12, wherein:

the ring has axially opposite sides that taper toward each other as the ring extends radially inward.

14. A fan comprising:

a center hub having a center axis of rotation of the fan and a peripheral surface;

a plurality of blades radiating outwardly from the hub peripheral surface, each blade of the plurality of blades has a radial length with an opposite base end and trailing edge, the base ends of the blades are connected with the hub peripheral surface, at least some of the blades have radial-flow and axial-flow portions, the radial-flow portions of the blades are positioned in planes that contain the hub center axis and the axial-flow portions of the blades have at least portions that are positioned in planes that are oriented at an angle relative to the planes of the blade radial-flow portions, and the blade radial-flow portions extend from the base ends to the trailing edges of the blades; and

,

the fan is mounted to a shaft of a motor and the motor has a housing with at least one vent opening in the housing adjacent the axial-flow portions of the blades.

15. The fan of claim 14, wherein:

the fan has a plurality of voids between adjacent blades of the fan that extend axially through the fan.

16. The fan of claim 14, wherein:

a ring extends around and interconnects the trailing edges of the blades and the blades are only connected together by the hub and the ring.

17. The fan of claim 14, wherein:

each of the blade axial-flow portions has a radial length between a distal end of the blade axial-flow portion and the base end of the blade and the distal end of the blade axial-flow portion is positioned radially between the base end and the trailing edge of the blade.

18. The fan of claim 14, wherein:

each of the radial-flow portions of the blades are axially rearward of the axial-flow portions of the blades.

19. The fan of claim 18, wherein:

each of the blade axial-flow portions has a radial length between a distal end of the blade axial-flow portion and the base end of the blade and the distal end of the blade axial-flow portion is positioned radially between the base end and the trailing edge of the blade.

21. The fan of claim 19, further comprising:

a ring extending around the hub interconnecting the trailing edge of the first section of each of the blades, there being a plurality of voids that extend axially through the fan between the blade axial-flow portions of each adjacent pair of the blades.

22. The fan of claim 21, wherein:

the ring is positioned where it connects rearward most edges of the blades.

23. A fan comprising:

a center hub having a center axis of rotation of the fan and a peripheral surface;

a plurality of blades radiating outwardly from the hub peripheral surface, each blade of the plurality of blades has a radial length with an opposite base end and trailing edge, the base ends of the blades are connected with the hub peripheral surface, at least some of the blades have radial-flow and axial-flow portions, the radial-flow portions of the blades are positioned in planes that contain the hub center axis and the axial-flow portions of the blades have at least portions that are positioned in planes that are oriented at an angle relative to the planes of the blade radial-flow portions, and the blade radial-flow portions extend from the base ends to the trailing edges of the blades; and

,

the fan is mounted to a shaft of a motor and the motor has a cover that encloses the fan with at least one exhaust opening in the cover adjacent the trailing edges of the fan blades.

24. A fan having a center axis of rotation, the axis defining axial and radial directions, the fan comprising:

a plurality of blades configured and adapted to draw air radially outward from the axis by revolving about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being radially closer to the center axis than the trailing edge of each of the blades and each of the blades having an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis, each of the blades having a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, cross-sections of the first section of each of the blade have chord-lines oriented parallel to the center axis, and at least some cross-sections of the second section of each of the blades have chord-lines oriented at an angle relative to the center axis; and

,

the angles of the chord-lines of the second section cross-sections of each of the blades increases with increasing radial distance of the cross-section from the center axis.

25. The fan of claim 24, wherein:

each of the blade second sections includes a radial-flow portion and an axial-flow portion, the radial-flow portion is positioned in a plane that contains the center axis and the axial-flow portion has at least some part that is positioned in a plane oriented at an angle relative to the plane of the radial-flow portion.

26. The fan of claim 24, wherein:

the radial-flow portion and the first section of each blade are positioned in a common plane that contains the center axis.

27. A fan comprising:

a center hub having a center axis and a peripheral surface, the center axis defining axial and radial directions;

a plurality of blades configured and adapted to draw air radially outward from the center axis by revolving with the center hub about the center axis, the plurality of blades each having a radially opposite base end and trailing edge, the base end of each of the blades being attached to the hub and each of the blades having an infinite number of cross-sections that each lie in a plane tangential to and radially spaced from the center axis, each of the blades having a first section extending radially inward from its trailing edge and a second section extending radially outward from its base end, cross-sections of the first section of each of the blades have chord-lines oriented parallel to the center axis, cross-sections of the second section of each of the blades have chord-lines oriented at an angle relative to the center axis, and the angle of the chord-lines of the second section cross-sections of each of the blades increases with increasing radial distance of the cross-section from the center axis;

each of the cross-sections of the second section of each of the blades consists of first and second portions and the first portion extends axially forward of the cross-sections of the first section of the blade; and

,

a ring extending around the hub interconnecting the trailing edges of the first section of each of the blades, there being a plurality of voids that extend axially through the fan between the second sections of each adjacent pair of the blades.

28. The fan of claim 27, wherein:

the first portion of each of the cross-sections of the second section of each of the blades curves relative to the center axis and the second portion of each of the cross-sections of the second section of each of the blades is substantially parallel to the center axis.

29. The fan claim 27, wherein:

a portion of each of the cross-sections of the first section of each of the blades extends axially rearward of the cross-sections of the second section of the blade.

30. The fan of claim 27, wherein:

the ring is positioned where it connects rearward most edges of the blades.