Multi-stage centrifugal fan

1. A multi-stage centrifugal fan assembly, comprising:

a body formed to define a flow path along which fluid is directed to flow;

a rotor disposed along the flow path and including at least first and second stages having substantially axially aligned rotor vanes formed to impart energy to the fluid moving in an outward radial direction when the at least first and second stages rotate about an axial centerline of the rotor; and

a stator having a radial dimension and stator vanes radially interposed between and substantially axially with the at least first and second stage rotor vanes to redirect a tangential direction of flow in a direction opposite a direction of rotor rotation,

each of the stator vanes being hook shaped and including a pressure surface, the pressure surface comprising a leading edge, a trailing edge, and a vertex, the leading edge located at an inner end of the pressure surface and proximate to the vanes of the first rotor stage and the trailing edge located at an outer end of the pressure surface and proximate to the vanes of the second rotor stage,

the leading edge and the trailing edge being configured to lead the vertex with respect to a direction of rotation of the rotor about the centerline and relative to the radial dimension of the stator.

2. The multi-stage centrifugal fan according to claim 1 , wherein the body comprises:

an inlet section, upstream from the rotor in an axial direction, through which the fluid flows toward the rotor;

an outlet tube, downstream from the rotor in a radial direction, into which the fluid flows from the rotor; and

an intermediate section in which the rotor is disposed and by which the outlet tube fluidly communicates with the inlet section.

3. The multi-stage centrifugal fan according to claim 1 , wherein the first and second stages are substantially coaxial.

4. The multi-stage centrifugal fan according to claim 1 , wherein the first and second stages are substantially coplanar.

5. The multi-stage centrifugal fan according to claim 1 , wherein the rotor vanes of the first and second stages are substantially spiral shaped.

6. The multi-stage centrifugal fan according to claim 1 , wherein the rotor vanes of the first and second stages have substantially similar shapes.

7. The multi-stage centrifugal fan according to claim 1 , wherein the stator is integrally coupled to an interior surface of the body.

8. The multi-stage centrifugal fan according to claim 1 , wherein the stator is rotationally fixed relative to the body.

9. The multi-stage centrifugal fan according to claim 1 , wherein the rotor vanes of the first stage are substantially uniformly spaced from one another, the rotor vanes of the second stage are substantially uniformly spaced from one another and the stator vanes are substantially uniformly spaced from one another.

10. A multi-stage centrifugal fan, comprising:

first and second stages of a rotor having substantially axially aligned rotor vanes formed to impart energy to a fluid moving in an outward radial direction when the first and second stages of the rotor rotate about a centerline; and

a stator having a radial dimension and stator vanes radially interposed between and substantially axially aligned with the first and second stage rotor vanes,

each of the stator vanes being hook shaped and including a pressure surface, the pressure surface comprising a leading edge, a trailing edge, and a vertex, the leading edge located at an inner end of the pressure surface and proximate to the vanes of the first rotor stage and the trailing edge located at an outer end of the pressure surface and proximate to the vanes of the second rotor stage,

the leading edge and the trailing edge being configured to lead the vertex with respect to a direction of rotation of the rotor about the centerline and relative to the radial dimension of the stator.

11. The multi-stage centrifugal fan according to claim 10 , wherein the rotor vanes of the first and second stages are substantially spiral shaped.

12. The multi-stage centrifugal fan according to claim 10 , wherein the stator is rotationally fixed.

13. The multi-stage centrifugal fan according to claim 10 , wherein the rotor vanes of the first stage are substantially uniformly spaced from one another, the rotor vanes of the second stage are substantially uniformly spaced from one another and the stator vanes are substantially uniformly spaced from one another.

14. A multi-stage centrifugal fan, comprising:

at least first and second stages of a rotor having substantially axially aligned rotor vanes formed to impart energy to a fluid moving in an outward radial direction when the at least first and second stages of the rotor are driven to rotate about a centerline; and

a stator having a radial dimension and stator vanes radially interposed between and substantially axially with the at least first and second stage rotor vanes to redirect a tangential direction of flow in a direction opposite a direction of rotor rotation,

each of the stator vanes being hook shaped and including a pressure surface, the pressure surface comprising a leading edge, a trailing edge, and the vertex, the leading edge located at an inner end of the pressure surface and proximate to the vanes of the first rotor stage and the trailing edge located at an outer end of the pressure surface and proximate to the vanes of the second rotor stage,

the leading edge and the trailing edge being configured to lead the vertex with respect to a direction of rotation of the rotor about the centerline and relative to the radial dimension of the stator.

15. The multi-stage centrifugal fan according to claim 14 , wherein the rotor vanes of the at least first and second stages are substantially spiral shaped.

16. The multi-stage centrifugal fan according to claim 14 , wherein the stator is rotationally fixed.

17. The multi-stage centrifugal fan according to claim 14 , wherein the rotor vanes of the first stage are substantially uniformly spaced from one another, the rotor vanes of the second stage are substantially uniformly spaced from one another and the stator vanes are substantially uniformly spaced from one another.