FAN IMPELLER WITH THIN BLADES

Abstract

An impeller for use in a fan system includes a hub extending along an axis of rotation and having a hub outer surface. There also are a plurality of blades extending radially outwardly of the hub outer surface. The blades have a unique cross-section at several different locations that result in relatively thin blades. A fan system and method are also disclosed.

Claims

1. An impeller for use in a fan system comprising: a hub extending along an axis of rotation and having a hub outer surface; a dimension X measured along the axis of rotation, a radial dimension Z defined in the radial dimension, and a Y axis defined laterally and perpendicular to the Z axis, and spaced by 90 degrees from the Z axis, there also being nine blades extending radially outwardly of the hub outer surface, and having a first cross-sectional contour and height at the hub outer surface as shown below, having a dimension Xs measured in the X direction and perpendicular to a Y axis and to a suction side and a dimension Xp measured in the Y direction perpendicular to the X axis and to a pressure side and a dimension Ys measured in the Y direction and perpendicular to the X axis to the suction side and a dimension Zp in the Z dimension in a radial dimension from the centerline to the pressure side and a dimension Zs measured in the same direction and to the suction side, and having the following dimensions with there being an origin for each of the nine blades, and all said origins being at a common location along the X axis, and at nine equally circumferentially spaced locations, with a point A defined at a leading edge, a point B being the closest point to the Y axis, and spaced from the leading edge, a point C being the closest point to the X axis, and spaced from the leading edge, and point D being at a trailing edge: TABLE-US-00022 Point No. XP YP ZP A 0.3365 −0.0643 0.9889 B 0.3568 −0.5000 0.9945 C 0.3732 −0.0489 1.0013 D 2.5986 −2.2174 1.2400 TABLE-US-00023 Point No. XS YS ZS A 0.3365 −0.0643 0.9889 B 0.3274 −0.0878 0.9903 C 0.3298 −0.1047 0.9951 D 2.5986 −2.2174 1.2400 further, there being a second cross-sectional contour spaced from the hub outer surface in a radially outer direction having the following dimensions: TABLE-US-00024 Point No. XP YP ZP A 0.2792 −0.0541 1.3143 B 0.2960 −0.0415 1.3262 C 0.3098 −0.0399 1.3358 D 2.3186 −2.1718 1.6250 TABLE-US-00025 Point No. XS YS ZS A 0.2792 −0.0541 1.3143 B 0.2713 −0.0756 1.3078 C 0.2733 −0.0921 1.3081 D 2.3186 −2.1718 1.6250 all of the dimensions measured above having a tolerance in the range of +/−0.020 inch (+/−0.0508 cm).

2. The impeller as set forth in claim 1, wherein the hub having an outer diameter along its outer surface with a first point taken at an axially forwardmost point, and measured in eleven spaced data points and having X and Z dimensions as follows: TABLE-US-00026 Point Nα. X Z 1 0.3343 0.5800 2 0.2952 0.6167 3 0.2269 0.7005 4 0.2110 0.8497 5 0.5521 1.1387 6 1.3384 1.6773 7 2.1246 2.2159 8 2.7422 2.6317 9 2.9848 2.7235 10 3.1657 2.7481 11 3.2940 2.7500 again with the tolerances of claim 1.

3. The impeller as set forth in claim 1, wherein said impeller is formed of an aluminum alloy containing at least magnesium and silicone.

4. The impeller as set forth in claim 1, wherein a third cross-sectional contour of the fan blades taken radially outward of the second cross-sectional contour has the following dimensions: TABLE-US-00027 Point No. XP YP ZP A 0.0648 −0.0158 2.5318 B 0.0805 −0.0081 2.5416 C 0.0924 −0.0097 2.5490 D 1.4994 −2.0383 2.7512 TABLE-US-00028 Point No. XS YS ZS A 0.0648 −0.0158 2.5318 B 0.0555 −0.0323 2.5259 C 0.0558 −0.0462 2.5258 D 1.4994 −2.0383 2.7512 again with the tolerances set forth in claim 1.

5. The impeller as set forth in claim 4, wherein a tip dimension of an initially formed impeller has the following cross-sectional dimensions: TABLE-US-00029 Point No. XP YP ZP A 0.0120 −0.0064 2.8313 B 0.0295 0.0000 2.8356 C 0.0418 −0.0026 2.8401 D 1.2984 −2.0055 3.0276 TABLE-US-00030 Point No. XS YS ZS A 0.0120 −0.0064 2.8313 B 0.0012 −0.0220 2.8311 C 0.0000 −0.0350 2.8334 D 1.2984 −2.0055 3.0276 again with the tolerances of claim 1.

6. The impeller as set forth in claim 5, wherein said second cross-section is taken at 20-30% of the maximum distance between the hub outer surface and a tip of an initially formed impeller.

7. The impeller as set forth in claim 1, wherein the impeller wherein the first cross-sectional contour having additional dimensions at points between the points 2 or 3 and point 4: TABLE-US-00031 XP YP ZP 0.4104 −0.0744 1.0230 0.5038 −0.1533 1.0774 0.6892 −0.3110 1.1723 1.1829 −0.7495 1.3528 1.6731 −1.2210 1.4292 2.1523 −1.7087 1.3958 2.4413 −2.0064 1.3243 2.5550 −2.1228 1.2858 2.6094 −2.1837 1.2620 TABLE-US-00032 XS YS ZS 0.3613 −0.1371 1.0156 0.4544 −0.2156 1.0687 0.6392 −0.3724 1.1612 1.1312 −0.8080 1.3350 1.6198 −1.2753 1.4044 2.0972 −1.7575 1.3644 2.3850 −2.0514 1.2895 2.4982 −2.1662 1.2498 2.5587 −2.2215 1.2297 and the second cross-sectional contour having additional dimensions at points between the points 2 or 3 and point 4: TABLE-US-00033 XP YP ZP 0.3437 −0.0635 1.3581 0.4284 −0.1411 1.4106 0.5959 −0.2965 1.5035 1.0403 −0.7288 1.6860 1.4810 −1.1931 1.7748 1.9118 −1.6747 1.7655 2.1717 −1.9709 1.7136 2.2740 −2.0874 1.6838 2.3187 −2.1471 1.6576 TABLE-US-00034 XS YS ZS 0.3024 −0.1245 1.3255 0.3878 −0.2018 1.3751 0.5565 −0.3563 1.4627 1.0036 −0.7843 1.6331 1.4465 −1.2422 1.7117 1.8793 −1.7160 1.6936 2.1403 −2.0069 1.6374 2.2430 −2.1212 1.6061 2.2974 −2.1772 1.5933 again with the tolerances set forth in claim 1.

8. A fan system comprising: an electric motor having a shaft, said shaft being fixed to rotate an impeller, and said electric motor and said impeller received within a housing having a fan inlet and a fan outlet; and said impeller having a hub extending along an axis of rotation and having a hub outer surface; a dimension X measured along the axis of rotation, a radial dimension Z defined in the radial dimension, and a Y axis defined laterally and perpendicular to the Z axis, and spaced by 90 degrees from the Z axis, there also being nine blades extending radially outwardly of the hub outer surface, and having a first cross-sectional contour and height at the hub outer surface as shown below, having a dimension Xs measured in the X direction and perpendicular to a Y axis and to a suction side and a dimension Xp measured in the Y direction perpendicular to the X axis and to a pressure side and a dimension Ys measured in the Y direction and perpendicular to the X axis to the suction side and a dimension Zp in the Z dimension in a radial dimension from the centerline to the pressure side and a dimension Zs measured in the same direction and to the suction side, and having the following dimensions with there being an origin for each of the nine blades, and all said origins being at a common location along the X axis, and at nine equally circumferentially spaced locations, with a point A defined at a leading edge, a point B being the closest point to the Y axis, and spaced from the leading edge, a point C being the closest point to the X axis, and spaced from the leading edge, and point D being at a trailing edge: TABLE-US-00035 Point No. XP YP ZP A 0.3365 −0.0643 0.9889 B 0.3568 −0.5000 0.9945 C 0.3732 −0.0489 1.0013 D 2.5986 −2.2174 1.2400 TABLE-US-00036 Point No. XP YP ZP A 0.2792 −0.0541 1.3143 B 0.2960 −0.0415 1.3262 C 0.3098 −0.0399 1.3358 D 2.3186 −2.1718 1.6250 further, there being a second cross-sectional contour spaced from the hub outer surface in a radially outer direction having the following dimensions: TABLE-US-00037 Point No. XS YS ZS A 0.3365 −0.0643 0.9889 B 0.3274 −0.0878 0.9903 C 0.3298 −0.1047 0.9951 D 2.5986 −2.2174 1.2400 TABLE-US-00038 Point No. XS YS ZS A 0.2792 −0.0541 1.3143 B 0.2713 −0.0756 1.3078 C 0.2733 −0.0921 1.3081 D 2.3186 −2.1718 1.6250 all of the dimensions measured above having a tolerance in the range of +/−0.020 inch (+/−0.0508 cm).

9. The fan system as set forth in claim 8, wherein the hub having an outer diameter along its outer surface with a first point taken at an axially forwardmost point, and measured in eleven equally data points and having X and Z dimensions as follows: TABLE-US-00039 Point No. X Z 1 0.3343 0.5800 2 0.2952 0.6167 3 0.2269 0.7005 4 0.2110 0.8497 5 0.5521 1.1387 6 1.3384 1.6773 7 2.1246 2.2159 8 2.7422 2.6317 9 2.9848 2.7235 10 3.1657 2.7481 11 3.2940 2.7500 again with the tolerances of claim 8.

10. The fan system as set forth in claim 8, wherein said impeller is formed of an aluminum alloy containing at least magnesium and silicone.

11. The fan system as set forth in claim 8, wherein a third cross-section of the fan blade taken radially outward of the second cross-section has the following dimensions: TABLE-US-00040 Point No. XP YP ZP A 0.0648 −0.0158 2.5318 B 0.0805 −0.0081 2.5416 C 0.0924 −0.0097 2.5490 D 1.4994 −2.0383 2.7512 TABLE-US-00041 Point No. XS YS ZS A 0.0648 −0.0158 2.5318 B 0.0555 −0.0323 2.5259 C 0.0558 −0.0462 2.5258 D 1.4994 −2.0383 2.7512 again with the tolerances set forth in claim 8.

12. The fan system as set forth in claim 8, wherein a tip dimension of an initially formed impeller has the following dimensions: TABLE-US-00042 Point No. XP YP ZP A 0.0120 −0.0064 2.8313 B 0.0295 0.0000 2.8356 C 0.0418 −0.0026 2.8401 D 1.2984 −2.0055 3.0276 TABLE-US-00043 Point No. XS YS ZS A 0.0120 −0.0064 2.8313 B 0.0012 −0.0220 2.8311 C 0.0000 −0.0350 2.8334 D 1.2984 −2.0055 3.0276 again taking the tolerances of claim 8.

13. The fan system as set forth in claim 8, wherein said second cross-section is taken at 20-30% of the maximum distance between the hub outer surface and a tip of an initially formed impeller.

14. The fan system as set forth in claim 8, wherein said input is to be connected to receive air from an aircraft cabin and said outlet is to be connected to deliver air back into the aircraft cabin.

15. A method of replacing an impeller in a fan air recirculation system comprising the steps of: removing an existing fan impeller from a fan system having an electric motor driving a shaft to drive the existing impeller, the existing impeller and the electric motor and shaft received within a housing having an inlet and an outlet; and replacing the existing impeller with a replacement impeller, the replacement impeller having a hub extending along an axis of rotation and having a hub outer surface; a dimension X measured along the axis of rotation, a radial dimension Z defined in the radial dimension, and a Y axis defined laterally and perpendicular to the Z axis, and spaced by 90 degrees from the Z axis, there also being nine blades extending radially outwardly of the hub outer surface, and having a first cross-sectional contour and height at the hub outer surface as shown below, having a dimension Xs measured in the X direction and perpendicular to a Y axis and to a suction side and a dimension Xp measured in the Y direction perpendicular to the X axis and to a pressure side and a dimension Ys measured in the Y direction and perpendicular to the X axis to the suction side and a dimension Zp in the Z dimension in a radial dimension from the centerline to the pressure side and a dimension Zs measured in the same direction and to the suction side, and having the following dimensions with there being an origin for each of the nine blades, and all said origins being at a common location along the X axis, and at nine equally circumferentially spaced locations, with a point A defined at a leading edge, a point B being the closest point to the Y axis, and spaced from the leading edge, a point C being the closest point to the X axis, and spaced from the leading edge, and point D being at a trailing edge: TABLE-US-00044 Point No. XP YP ZP A 0.3365 −0.0643 0.9889 B 0.3568 −0.5000 0.9945 C 0.3732 −0.0489 1.0013 D 2.5986 −2.2174 1.2400 TABLE-US-00045 Point No. XS YS ZS A 0.3365 −0.0643 0.9889 B 0.3274 −0.0878 0.9903 C 0.3298 −0.1047 0.9951 D 2.5986 −2.2174 1.2400 further, there being a second cross-sectional contour spaced from the hub outer surface in a radially outer direction having the following dimensions: TABLE-US-00046 Point No. XP YP ZP A 0.2792 −0.0541 1.3143 B 0.2960 −0.0415 1.3262 C 0.3098 −0.0399 1.3358 D 2.3186 −2.1718 1.6250 TABLE-US-00047 Point No. XS YS ZS A 0.2792 −0.0541 1.3143 B 0.2713 −0.0756 1.3078 C 0.2733 −0.0921 1.3081 D 2.3186 −2.1718 1.6250; and all of the dimensions measured above having a tolerance in the range of +/−0.020 inch (+/−0.0508 cm).

16. The method as set forth in claim 15, wherein the hub having an outer diameter along its outer surface with a first point taken at an axially forwardmost point, and measured in eleven equally spaced data points and having X and Z dimensions as follows: TABLE-US-00048 Point No. X Z 1 0.3343 0.5800 2 0.2952 0.6167 3 0.2269 0.7005 4 0.2110 0.8497 5 0.5521 1.1387 6 1.3384 1.6773 7 2.1246 2.2159 8 2.7422 2.6317 9 2.9848 2.7235 10 3.1657 2.7481 11 3.2940 2.7500 again with the tolerances of claim 15

17. The method as set forth in claim 16, wherein said replacement impeller is formed of an aluminum alloy containing at least magnesium and silicone.

18. The method as set forth in claim 15, wherein a third cross-section of the fan blades taken radially outward of the second cross-section has the following dimensions: TABLE-US-00049 Point No. XP YP ZP A 0.0648 −0.0158 2.5318 B 0.0805 −0.0081 2.5416 C 0.0924 −0.0097 2.5490 D 1.4994 −2.0383 2.7512 TABLE-US-00050 Point No. XP YP ZP A 0.0648 −0.0158 2.5318 B 0.0805 −0.0081 2.5416 C 0.0924 −0.0097 2.5490 D 1.4994 −2.0383 2.7512 again with the tolerances set forth in claim 15.

19. The method as set forth in claim 15, wherein a tip dimension of an initially formed replacement impeller has the following cross-sectional contour dimensions: TABLE-US-00051 Point No. XP YP ZP A 0.0120 −0.0064 2.8313 B 0.0295 0.0000 2.8356 C 0.0418 −0.0026 2.8401 D 1.2984 −2.0055 3.0276 TABLE-US-00052 Point No. XS YS ZS A 0.0120 −0.0064 2.8313 B 0.0012 −0.0220 2.8311 C 0.0000 −0.0350 2.8334 D 1.2984 −2.0055 3.0276 again with the tolerances of claim 1.

20. The impeller as set forth in claim 19, wherein said second cross-sectional contour is taken at 20-30% of a maximum distance between the hub outer surface and a tip of the initially formed replacement impeller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 shows a fan and motor system.

[0009] FIG. 2A is a front view of a fan impeller according to this disclosure.

[0010] FIG. 2B is a side view of the FIG. 2A impeller.

[0011] FIG. 3 is a cross-sectional view through a disclosed impeller.

[0012] FIG. 4 is a cross-section view through a blade on the impeller.

DETAILED DESCRIPTION

[0013] FIG. 1 shows a fan system 20. A source 10 delivers gas to an inlet 11 in a fan housing 22. The gas may be air. The air approaches an impeller 26 having a hub outer diameter at 28 and a plurality of fan blades 30 having a leading edge 32 and a trailing edge 34. A diffuser housing 38 is aft of the impeller 26. An electric motor 47 has a rotor 48 and a stator 50. The rotor 48 is driven to rotate, as known, and drives a shaft 42. Shaft 42 is secured to impeller 26 with a connection shown at 44, and including a nut 46. A bearing 40 supports the shaft 42. Impeller 26 moves air to outlet 36. In one application source 10 is an aircraft cabin that recirculates air back into a use 12 that may be the cabin. In such an application, the air is treated, such as by filtering, and then delivered into a mixing chamber where it is mixed with air from an air cycle machine. The mixed air is returned to the aircraft cabin.

[0014] FIG. 2A shows the impeller 26 with the shaft 42 and bolt connection 46. There are nine blades 30 in one embodiment. Each of the blades has a leading edge 32 and a trailing edge 34.

[0015] FIG. 2B is a side view showing the hub structure 28 mounting the blades 30.

[0016] FIG. 3 is a cross-sectional view through the impeller 26. As can be seen, there is a bore 52 to receive the shaft. There is a centerline CL. An outer surface 33 of the hub 28 is defined. A cross-section 70 of the blades 30 may be defined as next to the hub. Another cross-section 72 may be defined as next to the tip, and there is a tip cross-section 74. A diameter d is shown to the outer surface 33 of the hub. As can be appreciated from this view, the diameter d would vary along the surface 33. A dimension Z is defined radially outwardly from the centerline CL and a dimension X is defined along the centerline CL.

[0017] FIG. 4 shows a cross-section of each blade 30 as would be found at surface 33, and cross-sections 70 and 72, and 74.

[0018] A dimension Y is defined laterally and perpendicular to the Z axis, and spaced by 90 degrees from the Z axis. Dimensions X and Y are taken from an origin point 59. There is a suction side 62 and a pressure side 60 of blade 30. Dimensions Yp and Ys are shown measured from the axis X in the Y direction and two points on the suction side 62 and pressure side 60. Similarly, dimensions Xs and Xp are measured in the X direction from the Y axis and respectively to a point on the suction side 62 and to a point on the suction side 60. The dimensions Zp and Zs are taken in the Z direction to the point in question at each of the pressure 60 and suction 62 sides. These distances will vary along a length of the fan cross-sections at each cross-section 33, 70, 72 and 74.

[0019] Point 32 is at a leading edge. Point 29 is the closest point to the Y axis, and spaced from the leading edge. Point 35 is the closest point to the X axis, and spaced from the leading edge. Point 34 is at the trailing edge.

[0020] Note, for each of the nine blades 30 there is an origin 59. The origins are all at a common distance all the X dimensions. The Z and Y origin locations are at nine equally circumferentially spaced locations.

TABLE-US-00005 TABLE I AT 33 Point No. XP YP ZP 32 0.3365 −0.0643 0.9889 29 0.3568 −0.5000 0.9945 35 0.3732 −0.0489 1.0013 34 2.5986 −2.2174 1.2400

[0021] The following dimensions in ach of the supplemental tables will also be found spaced between points 29 or 35 and point 34.

TABLE-US-00006 TABLE I SUPPLEMENTAL AT 33 XP YP ZP 0.4104 −0.0744 1.0230 0.5038 −0.1533 1.0774 0.6892 −0.3110 1.1723 1.1829 −0.7495 1.3528 1.6731 −1.2210 1.4292 2.1523 −1.7087 1.3958 2.4413 −2.0064 1.3243 2.5550 −2.1228 1.2858 2.6094 −2.1837 1.2620

TABLE-US-00007 TABLE II AT 33 Point No. XS YS ZS 32 0.3365 −0.0643 0.9889 29 0.3274 −0.0878 0.9903 35 0.3298 −0.1047 0.9951 34 2.5986 −2.2174 1.2400

TABLE-US-00008 TABLE II SUPPLEMENTAL AT 33 XS YS ZS 0.3613 −0.1371 1.0156 0.4544 −0.2156 1.0687 0.6392 −0.3724 1.1612 1.1312 −0.8080 1.3350 1.6198 −1.2753 1.4044 2.0972 −1.7575 1.3644 2.3850 −2.0514 1.2895 2.4982 −2.1662 1.2498 2.5587 −2.2215 1.2297

TABLE-US-00009 TABLE III AT 70 Point No. XP YP ZP 32 0.2792 −0.0541 1.3143 29 0.2960 −0.0415 1.3262 35 0.3098 −0.0399 1.3358 34 2.3186 −2.1718 1.6250

TABLE-US-00010 TABLE III SUPPLEMENTAL AT 70 XP YP ZP 0.3437 −0.0635 1.3581 0.4284 −0.1411 1.4106 0.5959 −0.2965 1.5035 1.0403 −0.7288 1.6860 1.4810 −1.1931 1.7748 1.9118 −1.6747 1.7655 2.1717 −1.9709 1.7136 2.2740 −2.0874 1.6838 2.3187 −2.1471 1.6576

TABLE-US-00011 TABLE IV AT 70 Point No. XS YS ZS 32 0.2792 −0.0541 1.3143 29 0.2713 −0.0756 1.3078 35 0.2733 −0.0921 1.3081 34 2.3186 −2.1718 1.6250

TABLE-US-00012 TABLE IV SUPPLEMENTAL AT 70 XS YS ZS 0.3024 −0.1245 1.3255 0.3878 −0.2018 1.3751 0.5565 −0.3563 1.4627 1.0036 −0.7843 1.6331 1.4465 −1.2422 1.7117 1.8793 −1.7160 1.6936 2.1403 −2.0069 1.6374 2.2430 −2.1212 1.6061 2.2974 −2.1772 1.5933

TABLE-US-00013 TABLE V AT 72 Point No. XP YP ZP 32 0.0648 −0.0158 2.5318 29 0.0805 −0.0081 2.5416 35 0.0924 −0.0097 2.5490 34 1.4994 −2.0383 2.7512

TABLE-US-00014 TABLE V SUPPLEMENTAL AT 72 XP YP ZP 0.1178 −0.0348 2.5646 0.1785 −0.1131 2.6001 0.2969 −0.2689 2.6627 0.6062 −0.6930 2.7836 0.9122 −1.1324 2.8415 1.2149 −1.5780 2.8378 1.3997 −1.8511 2.8064 1.4726 −1.9589 2.7879 1.5062 −2.0145 2.7738

TABLE-US-00015 TABLE VI AT 72 Point No. XS YS ZS 32 0.0648 −0.0158 2.5318 29 0.0555 −0.0323 2.5259 35 0.0558 −0.0462 2.5258 34 1.4994 −2.0383 2.7512

TABLE-US-00016 TABLE VI SUPPLEMENTAL AT 72 XS YS ZS 0.0754 −0.0777 2.5372 0.1363 −0.1554 2.5716 0.2551 −0.3101 2.6320 0.5655 −0.7306 2.7478 0.8725 −1.1658 2.8012 1.1759 −1.6068 2.7936 1.3609 −1.8769 2.7601 1.4344 −1.9834 2.7413 1.4737 −2.0359 2.7330

TABLE-US-00017 TABLE VII AT 74 Point No. XP YP ZP 32 0.0120 −0.0064 2.8313 29 0.0295 0.0000 2.8356 35 0.0418 −0.0026 2.8401 34 1.2984 −2.0055 3.0276

TABLE-US-00018 TABLE VII SUPPLEMENTAL AT 74 XP YP ZP 0.0648 −0.0295 2.8530 0.1193 −0.1076 2.8851 0.2253 −0.2629 2.9414 0.5005 −0.6840 3.0495 0.7733 −1.1173 3.1008 1.0455 −1.5540 3.0979 1.2126 −1.8212 3.0707 1.2790 −1.9267 3.0547 1.3102 −1.9814 3.0437

TABLE-US-00019 TABLE VIII AT 74 Point No. XS YS ZS 32 0.0120 −0.0064 2.8313 29 0.0012 −0.0220 2.8311 35 0.0000 −0.0350 2.8334 34 1.2984 −2.0055 3.0276

TABLE-US-00020 TABLE VIII SUPPLEMENTAL AT 74 XS YS ZS 0.0177 −0.0658 2.8452 0.0722 −0.1437 2.8763 0.1783 −0.2984 2.9304 0.4538 −0.7176 3.0323 0.7271 −1.1480 3.0780 0.9995 −1.5813 3.0707 1.1667 −1.8463 3.0412 1.2331 −1.9508 3.0245 1.2694 −2.0024 3.0166

[0022] In addition, Table 9 reproduced below shows the X dimension along the hub and the Z dimension to the outer surface of the hub, and at the surface 33.

TABLE-US-00021 TABLE IX AT 33 Point No. X Z 1 0.3343 0.5800 3 0.2952 0.6167 6 0.2269 0.7005 9 0.2110 0.8497 12 0.5521 1.1387 15 1.3384 1.6773 18 2.1246 2.2159 21 2.7422 2.6317 24 2.9848 2.7235 27 3.1657 2.7481 30 3.2940 2.7500

[0023] All of the above dimensions have a tolerance of +/−0.020 inch (+/−0.0508 cm).

[0024] In the past, fan impellers for use in cabin air recirculation systems have been generally cast and thus heavy. Impeller 26 may be machined from a metal, and thus is more lightweight. In one application, the impeller 26 may be formed of Aluminum 60/61™ alloy. Aluminum 60/61™ alloy is an aluminum alloy containing at least magnesium and silicone.

[0025] In a unique benefit from this disclosure, an initial impeller may be made to each of the nine tables above, thus including the dimensions for the cross-sections at 33, 70, 72 and 74. However, subsequently, the fan blades may be cut away such that they do not extend as far radially outwardly for certain applications. It is presently envisioned that as many as three distinct impellers may be produced from the one initial impeller block. In the initial block, it could be said that cross-section 70 is between 20 and 30% of the entire maximum distance between the surface 33 and the tip 74. In one application it is at 25%. Similarly, the cross-section 72 may be between 70 and 80% of the maximum radius. In one embodiment, it is measured at 75%.

[0026] Note that the origin for all of the above tables have an X location selected at the leading edge 32 of the cross-section in Table VIII.

[0027] The uniquely contoured blades provide efficient operation in a long lived and light weight impeller.

[0028] Although an impeller has been disclosed, a worker of skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be cited to determine the true scope and content.