AU2003101030A4 - Blower wheel - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: Blower wheel The following statement is a full description of this invention, including the best method of performing it known to us: Freehills Carter Smith Beadle Melbourne 004411086 004410532 1A BLOWER WHEEL Field of the Invention This invention relates to blower wheels for air conditioners and heaters.

Backgqround of the Invention Current blower wheels are made from sheet metal, the blade of the blower comprising a curved sheet of metal arranged to drive the air as the wheel is rotated. Examples of blowers of this type are to be found in US Patents 6,203,278 (Mumpower) and US 6,179,561 (Horng).

Blower wheels have also been moulded from plastics material, and one example of such a wheel is to be found in US 5,988,979 (Wang). moulded wheels usually have blades which replicate the metal blades, which are of uniform thickness, as in the case of metal wheels.

Summary of the Invention and Obiect It is an object of the present invention to provide a blower wheel in which the blades are shaped to reduce noise while providing adequate air flow performance.

In accordance with a first aspect of the present invention there is provided a blower wheel having a series of blades arranged at the periphery, each blade having an inner longitudinal edge and an outer longitudinal edge, a flow path being defined between adjacent blades wherein each flow path progressively converges from the inner edges of the adjacent blades to the outer edges.

Preferably, the convergence of the flow path is achieved by having the spacing between adjacent blades progressively converge from the inner edges to the outer edges. The air flow along the air flow path will thus be accelerated which in turn minimises or eliminates air flow separation between adjacent blades. By reducing the air flow separation between the adjacent blades compared to known blowers, a reduction in noise levels can be achieved whilst keeping the profile practical for operating and manufacturing purposes.

004410532 2 In a most preferred form of the invention, the convergence between adjacent blades is substantially linear. In one form of the invention, this may be equated to having a linear relationship between the spacing between adjacent blades and the distance along the air flow path.

Preferably, the blades have a variation in thickness along the air flow path to achieve the variation and spacing between adjacent blades. Suitably, the blades are also curved from the inner to the outer edge as is known in the art. In a most preferred form of the invention, the blade shape approximates that of an aerofoil.

The blades are preferably uniform in cross section over their length.

Suitably, the blower wheel also includes a support structure to support the blades.

Preferably, this is in the form of a hub wheel arranged at.one end of the blades and connected to the blades with a rim/annulus connected to the other end of the blades. The hub wheel may comprise a circular plate or disc which is either flat or shaped.

In a preferred form of the invention, the blower wheel is moulded from plastics material. Most preferably, the support structure is integrally moulded with the blades.

The invention may have application to both dual and single inlet blower wheels. In case of a dual inlet blower wheel, the hub wheel may be centrally disposed relative to the blades with two annular rims connected to respective outer ends of the blades.

The blower wheel in accordance with the present invention may contain any number of blades which are arranged around the periphery of the hub wheel. In one form of the invention, the number of blades may be an indivisible prim number to assist in avoiding undesirable vibration and/or resonant frequency.

Brief Description of the Drawinqs In order that the invention may be more fully understood, one embodiment will now be described by way of example with reference to the drawings in which: 004410532 3 Figure 1 is a side view partially in section of a blower wheel in accordance with the prior art; Figure 2 is a top view, partially in section, of the blower wheel of Figure 1; Figure 3 is a side view, partially in section of a blower wheel in accordance with a preferred embodiment of the present invention; Figure 4 is a top view of the blower wheel of Figure 3 shown with various different sectioning; Figure 5 is a detailed view of three spaced blades of the blower wheel of Figure 3; Figure 6 is a detailed view of the blade profile; Preferred embodiment of the present invention Referring firstly to the prior art blower wheel lof Figures 1 and 2, it will be noted that the blower blades are metal blades 2 of uniform thickness, supported by a central hub 3.

Figures 3 and 4 illustrate a preferred form of a blower wheel 10 constructed from plastics material. The blower wheel 10 comprises a central hub wheel 12 comprising a circular disc portion 14, a central hub 16 with strengthening fins 18, provided on both sides of the plate-like portion 14.

Arranged about the peripheral of the plate-like portion 14 and extending from both sides of the plate-like portion 14 is a series of spaced blades 22, 24 which can be seen from Figure 4. Figure 4 includes a top view of the blower wheel and includes two different cross-sectional views. From left to right of Figure 4, initially, the top of the blower wheel 10 is shown. The blades 22 are connected to an annular rim 26 at the outer longitudinal edge of the blades 22. Moving towards the right of Figure 4, a cross-sectional view through B-B of Figure 3 is shown. In this view, the blades 22 are illustrated in cross-section. In this view, blades 24 are illustrated in phantom. Thus, it can be seen that blades 22 and blades 24 are offset. The right hand side of Figure 4 is a cross-section through A-A of Figure 3, showing the 004410532 4 blades 24 in cross-section. As shown, the outer end of the blades 24 are connected to annular rim 28.

Figures 5 and 6 illustrate in greater detail the geometry of the blades 22, 24 and the relationship between adjacent blades 22, 24. Although only blade 22 has been illustrated in Figure 5 and 6, the same geometry and spacing applies, except that the blades 24 are offset relative to blades 22.

In Figure 5, it can be seen that each of the blades 22 possesses an inner longitudinal edge 30 and an outer longitudinal edge 32 (illustrated in phantom). A flow path 36 is thereby provided between adjacent blades 22. From the inner longitudinal edge 30 to the outer longitudinal edge 32, the flow path progressively converges by converging the spacing between the adjacent blades 22. This is depicted in Figure 6 where it can be seen the diameter of the circles arranged along the flow path 36 progressively decrease from a diameter of 11.8 to a diameter of 9.44. It will be appreciated that the dimensions illustrated in Figure 6 are merely indicative only and is not to be seen as limiting the scope of the invention.

From Figures 5 and 6, it can be seen that the blade profile 22 corresponds roughly to an aerofoil profile in order to achieve curving of the flow path 36 and the converging spacing between adjacent blades.

The blower wheel may be integrally moulded from plastics material. For high temperature applications, the material used may be 30% Mineral Filled Nylon 6.

For standard applications, the material may comprise 40% Calcium Carbonate Filled Polypropylene. In use, the blower wheel rotates in the direction indicated by arrow R as depicted in Figures 4 and By adopting the profile illustrated, the required air flow is created while keeping the air flow separation between adjacent blades to a minimum, thereby reducing the noise created by the blower wheel as it is rotated at the required speed to generate the required air flow.

004410532 While one particular aerofoil shape has been illustrated, it will be appreciated that other shapes which produce linearly convergent paths between adjacent blades will result in equally acceptable reductions in noise levels.

Since other modifications within the spirit and scope of the invention may be readily effected by persons skilled in the art, it is to be understood that the invention is not limited to the particular embodiment described, by way of example, hereinabove.

It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims (4)

1. A blower wheel having a series of blades arranged at the periphery, each blade having an inner longitudinal edge and an outer longitudinal edge, a flow path being defined between adjacent blades wherein each flow path progressively converges from the inner edges of the adjacent blades to the outer edges.

2. The blower wheel as claimed in claim 1 wherein a linear relationship exists between the spacing between adjacent blades and the distance along the flow path.

3. The blower wheel as claimed in claim 1 or claim 2 wherein each blade has an aerofoil profile.

4. The blower wheel as claimed in any one of the preceding claims moulded from plastics material. A blower wheel substantially as hereinbefore described with reference to the accompanying figures. Freehills Carter Smith Beadle 18 December 2003 Registered Patent Attorneys for TORIN INDUSTRIES PTY LTD