Mixed flow roof exhaust fan

• US 8,052,386 B1
• Filed: 12/29/2009
• Issued: 11/08/2011
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Loren Cook Company
• Original Assignee: Loren Cook Company
• Inventors: Jennings, Rickey W., Valbracht, Robert A., Fitzpatrick, Erich R.
• Primary Examiner(s): WIEHE, NATHANIEL EDWARD
• Application Number:
  US12/655,348
• Time in Patent Office: 679 Days
• Field of Search: 415/211.2, 415/218.1, 415/219.1, 415/220, 415/223, 416/185, 416/186.R, 416/187, 416/188, 416/223.B, 416/238, 416/242, 454/341
• US Class Current: 415/218.1
• CPC Class Codes: F04D 25/08 the working fluid being air, e.g. for ventilation
• CPC Class Codes: F04D 29/281 for fans or blowers
• CPC Class Codes: F04D 29/30 Vanes

Abstract

A mixed flow fan wheel has a convex hub, an axially-spaced away concave annular shroud, and a plurality of angularly distributed blades extending between and interconnecting the hub and shroud, all which cooperatively define a plurality of inter-blade flow channels. Each has a pressure surface and spaced suction surface extending not only between spaced inlet and discharge edges but also, crosswise thereto, spaced hub-side and shroud-side edges. Each discharge edge is convex relative a center of geometry of the blade therefor. Each inter-blade flow channel originates in a generally rectangular shape between flanking inlet edges and terminates in another generally rectangular shape between flanking discharge edges, with a procession of gradations of generally rectangular shapes forming a progressive transition therebetween. Moreover, each inter-blade flow channel twists or corkscrews from inlet thereof to the discharge.

Claims

1. A mixed flow fan wheel comprising:

a convex hub;

an axially-spaced away, concave annular shroud;

a plurality of angularly distributed blades extending between and interconnecting the hub and shroud, all which cooperatively define a plurality of inter-blade flow channels;

wherein each blade has a pressure surface and spaced suction surface extending not only between spaced leading and trailing edges but also, transversely thereto, spaced hub-side and shroud-side edges;

wherein the blades are arranged in backwardly-swept formations;

wherein each blade divides space into two spaces, pressure-side space interfacing the pressure surface and suction-side space interfacing the suction surface;

wherein both the leading edge and the trailing edge trace a respective span between the hub-side and shroud-side edges respectively; and

wherein each blade is warped into the pressure- and suction-side spaces such that at least twenty-five percent (25%) of the leading edge'"'"'s span is convex into pressure-side space and, conversely, at least twenty-five percent (25%) of the trailing edge'"'"'s span is concave into pressure-side space.

2. The mixed flow fan wheel of claim 1 further comprising:

a fixed, annular convex diffuser formed with a central opening having an inner diameter sized for closely surrounding the hub'"'"'s outer periphery.

3. The mixed flow fan wheel of claim 1 further comprising:

interchangeable upblast-configured and downblast configured windbands for interchangeable assembly with the mixed flow fan wheel and adapted to allow selection reversibly between an upblast-configured roof exhaust fan and a downblast-configured roof exhaust fan.

4. The mixed flow fan wheel of claim 1 wherein:

at least fifty percent (50%) of the leading edge'"'"'s span is convex into pressure-side space.

5. The mixed flow fan wheel of claim 1 wherein:

at least fifty percent (50%) of the trailing edge'"'"'s span is concave into pressure-side space.

6. The mixed flow fan wheel of claim 5 wherein:

at least fifty percent (50%) of the leading edge'"'"'s span is convex into pressure-side space.

7. The mixed flow fan wheel of claim 1 wherein:

at least seventy-five percent (75%) of the leading edge'"'"'s span is convex into pressure-side space.

8. The mixed flow fan wheel of claim 1 wherein:

at least seventy-five percent (75%) of the trailing edge'"'"'s span is concave into pressure-side space.

9. The mixed flow fan wheel of claim 8 wherein:

at least seventy-five percent (75%) of the leading edge'"'"'s span is convex into pressure-side space.