Fan impeller with thin blades

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.

BACKGROUND OF THE INVENTION

This application relates to an impeller for a fan wherein the fan blades are relatively thin compared to existing impellers.

Fan are utilized in any number of applications, and typically have a motor driving an impeller. The impeller has a plurality of blades which are driven to rotate and move a gas from an inlet to an outlet.

One application for such a system is in a cabin air recirculation system for use on an aircraft. In this application, the fan receives air from an aircraft cabin, and recirculates it back into the cabin.

Existing fan impellers in many such systems have been formed as a cast item which is relatively heavy.

SUMMARY OF THE INVENTION

An impeller for use in a fan system includes a hub extending along an axis of rotation and having a hub outer surface. A dimension X is measured along the axis of rotation, a radial dimension Z is defined in the radial dimension, and a Y axis is defined laterally and perpendicular to the Z axis, and spaced by 90 degrees from the Z axis. There are also 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. All the origins are 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:

There is a second cross-sectional contour spaced from the hub outer surface in a radially outer direction having the following dimensions:

All of the dimensions measured above have a tolerance in the range of +/−0.020 inch (+/−0.0508 cm).

A fan system and a method of replacing a fan impeller are also disclosed.

DETAILED DESCRIPTION

FIG.1shows a fan system20. A source10delivers gas to an inlet11in a fan housing22. The gas may be air. The air approaches an impeller26having a hub outer diameter at28and a plurality of fan blades30having a leading edge32and a trailing edge34. A diffuser housing38is aft of the impeller26. An electric motor47has a rotor48and a stator50. The rotor48is driven to rotate, as known, and drives a shaft42. Shaft42is secured to impeller26with a connection shown at44, and including a nut46. A bearing40supports the shaft42. Impeller26moves air to outlet36. In one application source10is an aircraft cabin that recirculates air back into a use12that 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.

FIG.2Ashows the impeller26with the shaft42and bolt connection46. There are nine blades30in one embodiment. Each of the blades has a leading edge32and a trailing edge34.

FIG.2Bis a side view showing the hub structure28mounting the blades30.

FIG.3is a cross-sectional view through the impeller26. As can be seen, there is a bore52to receive the shaft. There is a centerline CL. An outer surface33of the hub28is defined. A cross-section70of the blades30may be defined as next to the hub. Another cross-section72may be defined as next to the tip, and there is a tip cross-section74. A diameter d is shown to the outer surface33of the hub. As can be appreciated from this view, the diameter d would vary along the surface33. A dimension Z is defined radially outwardly from the centerline CL and a dimension X is defined along the centerline CL.

FIG.4shows a cross-section of each blade30as would be found at surface33, and cross-sections70and72, and74.

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 point59. There is a suction side62and a pressure side60of blade30. Dimensions Yp and Ys are shown measured from the axis X in the Y direction and two points on the suction side62and pressure side60. Similarly, dimensions Xs and Xp are measured in the X direction from the Y axis and respectively to a point on the suction side62and to a point on the suction side60. The dimensions Zp and Zs are taken in the Z direction to the point in question at each of the pressure60and suction62sides. These distances will vary along a length of the fan cross-sections at each cross-section33,70,72and74.

Point32is at a leading edge. Point29is the closest point to the Y axis, and spaced from the leading edge. Point35is the closest point to the X axis, and spaced from the leading edge. Point34is at the trailing edge.

Note, for each of the nine blades30there is an origin59. 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.

The following dimensions in ach of the supplemental tables will also be found spaced between points29or35and point34.

TABLE ISUPPLEMENTAL AT 33XPYPZP0.4104−0.07441.02300.5038−0.15331.07740.6892−0.31101.17231.1829−0.74951.35281.6731−1.22101.42922.1523−1.70871.39582.4413−2.00641.32432.5550−2.12281.28582.6094−2.18371.2620

TABLE IISUPPLEMENTAL AT 33XSYSZS0.3613−0.13711.01560.4544−0.21561.06870.6392−0.37241.16121.1312−0.80801.33501.6198−1.27531.40442.0972−1.75751.36442.3850−2.05141.28952.4982−2.16621.24982.5587−2.22151.2297

TABLE IIISUPPLEMENTAL AT 70XPYPZP0.3437−0.06351.35810.4284−0.14111.41060.5959−0.29651.50351.0403−0.72881.68601.4810−1.19311.77481.9118−1.67471.76552.1717−1.97091.71362.2740−2.08741.68382.3187−2.14711.6576

TABLE IVSUPPLEMENTAL AT 70XSYSZS0.3024−0.12451.32550.3878−0.20181.37510.5565−0.35631.46271.0036−0.78431.63311.4465−1.24221.71171.8793−1.71601.69362.1403−2.00691.63742.2430−2.12121.60612.2974−2.17721.5933

TABLE VSUPPLEMENTAL AT 72XPYPZP0.1178−0.03482.56460.1785−0.11312.60010.2969−0.26892.66270.6062−0.69302.78360.9122−1.13242.84151.2149−1.57802.83781.3997−1.85112.80641.4726−1.95892.78791.5062−2.01452.7738

TABLE VISUPPLEMENTAL AT 72XSYSZS0.0754−0.07772.53720.1363−0.15542.57160.2551−0.31012.63200.5655−0.73062.74780.8725−1.16582.80121.1759−1.60682.79361.3609−1.87692.76011.4344−1.98342.74131.4737−2.03592.7330

TABLE VIISUPPLEMENTAL AT 74XPYPZP0.0648−0.02952.85300.1193−0.10762.88510.2253−0.26292.94140.5005−0.68403.04950.7733−1.11733.10081.0455−1.55403.09791.2126−1.82123.07071.2790−1.92673.05471.3102−1.98143.0437

TABLE VIIISUPPLEMENTAL AT 74XSYSZS0.0177−0.06582.84520.0722−0.14372.87630.1783−0.29842.93040.4538−0.71763.03230.7271−1.14803.07800.9995−1.58133.07071.1667−1.84633.04121.2331−1.95083.02451.2694−2.00243.0166

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 surface33.

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

In the past, fan impellers for use in cabin air recirculation systems have been generally cast and thus heavy. Impeller26may be machined from a metal, and thus is more lightweight. In one application, the impeller26may be formed of Aluminum 60/61™ alloy. Aluminum 60/61™ alloy is an aluminum alloy containing at least magnesium and silicone.

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 at33,70,72and74. 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-section70is between 20 and 30% of the entire maximum distance between the surface33and the tip74. In one application it is at 25%. Similarly, the cross-section72may be between 70 and 80% of the maximum radius. In one embodiment, it is measured at 75%.

Note that the origin for all of the above tables have an X location selected at the leading edge32of the cross-section in Table VIII.

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

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.