Fan arrangement, impeller and associated method of manufacture

Abstract

A fan arrangement (12) including a common hub (14) and a plurality of blades (16) arranged to radially extend from the hub (14). The fan arrangement (14) being configurable or convertible to provide: a first configuration in which a first set of the plurality of blades are shaped to provide an axial fan (13), and a second configuration in which a shroud arrangement (30) is fitted to the hub (14) to provide a tapered aerodynamic surface (33) extending about the hub (14) and a second set of the plurality of blades are shaped to provide a mixed flow fan (15). A system, method and shroud arrangement are also disclosed.

Description

Fan Arrangement., Impeller and associated Method of ManufactureRelated Applications

[0001] This application claims priority from Australian provisional patent application no. AU 2023902173 filed on 6 July 2023 the contents of which are incorporated by reference.Technical Field

[0002] The invention relates to a fan arrangement, an impeller for a fan arrangement and an associated method of manufacture.Background

[0003] Fan arrangements typically have an impeller to generate fluid flow. The impeller may include a hub and a series of blades extending radially from the hub. The impeller may be used within a housing such as duct or the like to drive fluid flow through the duct. The hub may be cast and include sockets into which a spigot at the end of each of the blades are inserted and secured thereto.

[0004] In some cases, when configured as an axial fan, such fan arrangements may be configured with blades to generate fluid flow by virtue of a pressure differential across the blades thereby having axial fan characteristics. In another cases, such as when the impeller is used within a duct, such fan arrangements may be configured as mixed flow or impulse fans in which may include blades configured to generate fluid flow at least in part by impulse or momentum imparted to the fluid by the blades thereby having mixed flow fan characteristics.

[0005] When being configured as a mixed flow fan it is desirable to have a tapered hub, and in such mixed flow fans, the hub may be formed with a permanent tapered section which may be integrally formed with the hub.

[0006] A problem with such fan arrangements and impellers is that the entire arrangement is configured to be for an axial fan with a non-taper hub or a mixed flow fan with a taper hub - not both, and this requires two separate hub configurations which is costly and inefficient.

[0007] The invention disclosed herein seeks to overcome one or more of the above identified problems or at least provide a useful alternative.Summary

[0008] In accordance with a first broad aspect there is provided, a fan arrangement including a common hub and a plurality of blades arranged to radially extend from the hub, the fan arrangement being configurable or convertible to provide: a first configuration in which a first set of the plurality of blades are shaped to provide an axial fan; and a second configuration in which a shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface extending about the hub and a second set of the plurality of blades are shaped to provide a mixed flow fan.

[0009] In an aspect, the shroud arrangement includes a forward shroud section and a rear shroud section which when coupled provide the tapered aerodynamic surface.

[0010] In another aspect, at least one of the forward and rear shroud sections include recesses adapted to form apertures through which the plurality of blades extend.

[0011] In yet another aspect, the forward and rear shroud sections each include recesses adapted to form apertures through which the plurality of blades extend.

[0012] In yet another aspect, each recess includes a notch shaped to interlock with respective ones of the plurality of blades.

[0013] In yet another aspect, each of the forward shroud section and the rear shroud section include corresponding fingers adapted to locate the forward shroud section and the rear shroud section with one another.

[0014] In yet another aspect, each of the forward shroud section and the rear shroud section include corresponding fingers adapted to fit with one another.

[0015] In yet another aspect, each of the forward shroud section and the rear shroud section includes an inner skirt adapted to attach with the common hub.

[0016] In yet another aspect, the hub includes a forward hub section and a rear hub section, and wherein the forward shroud section is coupled to the forward hub section via its inner skirt and the rear shroud section is coupled to the rear hub section via its inner skirt.

[0017] In yet another aspect, the forward and rear shroud sections are removably coupled to the hub.

[0018] In yet another aspect, the common hub is a cast hub.

[0019] In yet another aspect, the common hub includes a forward hub section and a rear hub section.

[0020] In yet another aspect, the common hub includes sockets, and each the plurality of blades includes a spigot receivable by respective sockets.

[0021] In accordance with a second broad aspect there is provided, a system to form an axial flow fan and a mixed flow fan from a common hub, the system including: a common hub arrangement; a plurality of blades arranged to radially extend from the hub; and a shroud arrangement fittable to the hub, wherein, in a first configuration, a first set of the plurality of blades are coupled to the common hub arrangement and the shroud arrangement is omitted, the first set of the plurality of blades being shaped to provide the axial flow fan; and, in a second configuration, the shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface extending from the hub and a second set of the plurality of blades are coupled to the common hub arrangement, the second set of the plurality of blades being shaped to provide the mixed flow fan.

[0022] In accordance with a third broad aspect there is provided, a method of forming an axial flow fan and a mixed flow fan from a common hub, wherein, to form the axial flow fan in a first configuration the common hub is fitted with a plurality of blades that are shaped to provide an axial flow fan, and, wherein to form the mixed flow fan in a second configuration the common hub is fitted with a different set of the plurality of blades that are shaped to provide the mixed flow fan and a shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface extending from the hub.

[0023] In accordance with a fourth broad aspect there is provided, a method of converting an axial flow fan to a mixed flow fan, the method including: replacing a plurality of blades fitted to a hub of the axial flow fan with a new set of plurality of blades shaped to provide the mixed flow impeller; and fitting a shroud arrangement to the hub to provide a tapered aerodynamic surface extending from the hub.

[0024] In accordance with a fifth broad aspect there is provided, a shroud arrangement for converting an axial flow fan to a mixed flow fan, the shroud arrangement including a first shroud section and a second shroud section which are adapted to couple to a common hub and to one another to provide a tapered aerodynamic surface from which a plurality of blades radially extend.

[0025] In an aspect, the forward and rear shroud sections each include recesses adapted to form apertures through which the plurality of blades extend.

[0026] In another aspect, each recess includes a notch shaped to interlock with respective ones of the plurality of blades.

[0027] In yet another aspect, each of the forward shroud section and the rear shroud section include corresponding fingers adapted to locate the forward shroud section and the rear shroud section with one another.

[0028] In still yet another aspect, each of the forward shroud section and the rear shroud section includes an inner skirt adapted to attach with the common hub.

[0029] In accordance with a sixth broad aspect there is provided, a fan arrangement including a common hub arrangement and a plurality of blades arranged to radially extend from the hub, the fan arrangement being configurable or convertible to provide: a first configuration in which a first set of the plurality of blades are shaped to provide an axial fan; and a second configuration in which a shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface skirting the hub and a second set of the plurality of blades are shaped to provide a mixed flow fan.Brief Description of the Figures

[0030] The invention is described, by way of non-limiting example only, by reference to the accompanying figures, in which;

[0031] Figure 1 is an exploded parts perspective view illustrating a first configuration of an impeller of a fan arrangement;

[0032] Figure 2 is a front view illustrating the first configuration of the impeller;

[0033] Figure 3 is a side view illustrating the first configuration of the impeller;

[0034] Figure 4 is an exploded parts perspective view illustrating a second configuration of the impeller of the fan arrangement;

[0035] Figure 5 is front view illustrating the second configuration of the impeller of the fan arrangement;

[0036] Figure 6 is a side sectional view illustrating the second configuration of the impeller of the fan arrangement;

[0037] Figure 7 is rear view illustrating the second configuration of the impeller of the fan arrangement;

[0038] Figure 8 is a side view illustrating the second configuration of the impeller of the fan arrangement;

[0039] Figure 9 is a front side exploded parts view illustrating the second configuration of the impeller of the fan arrangement;

[0040] Figure 10 is a back side exploded parts view illustrating the second configuration of the impeller of the fan arrangement;

[0041] Figures I la and 1 lb are respectively rear side and front side perspective views illustrating a front shroud section;

[0042] Figures 12a and 12b are respectively rear side and front side perspective views illustrating a rear shroud section;

[0043] Figure 13 is an exploded parts perspective view illustrating a second example of an impeller of a fan arrangement in the second configuration showing an alternative shroud; and,

[0044] Figures 14a and 14b are respectively front and rear perspective views illustrating the second example of the impeller of the fan arrangement in the second configuration.Detailed Description

[0045] Referring to Figures 1 to 3 there is shown a first example of a first configuration of an impeller 10 of a fan arrangement 12 which is adapted to function as an axial flow fan 13 with or without a surrounding duct (not shown).

[0046] The fan arrangement 12 is convertible to a second configuration adapted to function as a mixed flow fan 15 preferably within the surrounding duct. Such a duct may be a cylindrical duct having a diameter about the same, or slightly larger, than a diameter of the impeller 10.

[0047] The first configuration is firstly described below in relation to Figures 1 to 3, and the second configuration is then described with reference to Figures 4 to 12b. Each of the first and second configurations include a common cast hub arrangement 14.

[0048] Referring firstly to the first configuration, the impeller 10 includes the cast hub arrangement 14 and a plurality of blades 16 which are arranged to extend radially from the cast hub arrangement 14. Each the plurality of blades 16 includes a blade section 17 and a spigot 19.

[0049] The blade section 17 may be any suitable size and shape and may include blades with flat or non-aerofoil cross sections and blades with aerofoil cross sections. However, preferably, in the first configuration, the blades 16 are a first set of axial blades 16a having aerofoil cross sections in which the flow is driven by a pressure differential over the blades 16. Such an impeller 10 is, in use, rotationally driven by a motor (not shown).

[0050] The cast hub arrangement 14 include a forward hub section 18 and a rear hub section 20 which generally provide two halves of the hub arrangement 14. Each of the forward hub section 18 and a rear hub section 20 include respective forward and rear socket sections 22, 24 which when placed together form sockets 26 into which spigots 19 of the plurality of blades 16 are captured and retained in an assembled condition.

[0051] The plurality of blades 16 may be adjusted in pitch within the sockets 26 and the welded or otherwise secured in place. The forward hub section 18 and the rear hub section 20 may also be welded or otherwise secured together.

[0052] Referring now to Figures 4 to 8, there is shown a first example of a second configuration of the impeller 10 in which like numerals denote like parts. In this example, the cast hub arrangement 14 is the same or substantially the same as the first example. Accordingly, as aforesaid, the cast hub arrangement 14 may be common between the first and second configurations.

[0053] In the second configuration, a shroud arrangement 30 is also provided which, in essence, converts the impeller 10 to be suitable as a mixed flow or impulse impeller 15 and the plurality of blades 16 may be a second set of blades 16b which may have a different shape so as to be suitable for mixed flow in which the flow is driven by a combination of a pressure differential over the blade and momentum or impulse imparted to the flow.

[0054] Accordingly, it may be appreciated that the arrangement of the impeller 10 allows for a single or common cast hub arrangement 14 to be manufactured, and then only the plurality of blades 16 and the shroud arrangement 30 may be changed. Such an impeller 10 may be considered “convertible” in which it may be adapted to be either an axial fan or a mixed flow type fan.

[0055] Turning the shroud arrangement 30 in more detail, the shroud arrangement 30 includes a forward shroud section 32 and a rear shroud section 34 that are fitted together in an assembled condition to provide the shroud arrangement 30. The shroud arrangement 30 provides a frustoconical surface 31 and provides the cast hub arrangement 14 with a tapered aerodynamic surface 33 as best shown in Figure 6.

[0056] In this example, the forward shroud section 32 and the rear shroud section 34 are form two parts or halves of the shroud arrangement 30 and meet at about a centre line of the spigots 19 of the blades 16. The fitment provides for the congruent frustoconical surface 31.

[0057] In this arrangement, the forward shroud section 32 and the rear shroud section 34 include respective recesses 29, 35 which form apertures 38 through which the spigots 19 of the blades 16, or at least a base 40 of the blades 16, extend into the sockets 26. Each of recesses 29, 35 may include a notch 39, 41, shown best in Figure 9, which locates with respect fitted blades 16.

[0058] It may be appreciated that the arrangement of the forward shroud section 32 and the rear shroud section 34 allow fitment before or after the blades 16 have been fitted to the cast hub arrangement 14.

[0059] It is noted that once the forward shroud section 32 and the rear shroud section 34 are secured together, they are relatively self-supporting and form a non- structural shroud for aerodynamic purposes only. For example, in Figure 6 it may be seen that the forward shroud section 32 and the rear shroud section 34 are non-structural and cantilevered from the cast hub arrangement 14.

[0060] In more detail, referring more specifically to Figures 9 to 12b, the forward shroud section 32 includes an annular body 43 with a tapered forward surface 45 and radial fingers 46. Each of the radial fingers 46 includes respective locators 42 in the form of tabs 44. The locators 42 are best shown in Figures I la and 11b. The annular body 43 includes an inward facing skirt 47 that has apertures 49 allowing the forward shroud section 32 to be removably bolted to the forward hub section 18.

[0061] Similarly, the rear shroud section 34 includes an annular body 52 with a tapered rear surface 54 and radial fingers 56. Each of the radial fingers 46 includes respective further corresponding locators 48. The corresponding locators 48 are best shown in Figures 12a and 12b. The annular body 52 includes an inward facing skirt 57 that has apertures 59 allowing the rear shroud section 34 to be removably bolted to the rear hub section 20.

[0062] The locators 42 of the forward shroud section 32 are arranged to fit and locate with the corresponding locators 48 of the rear shroud section 34. The corresponding locators 48 of the rear shroud section 34 are provided in the form of sleeves 50 into which the tabs 44 of the forward shroud section 32 are fitted.

[0063] Figures 9 and 10 also show a hub coupling arrangement 60 which allows the forward and rear hub sections 18, 20 to be coupled together such as with bolts or the like.

[0064] In relation to a method of manufacturing, the forward hub section 18 and the rear hub section 20 may be cast to form components that may be used for either of the above-described two configurations - with or without the shroud arrangement 30. Thedesired plurality of blades 16 may then be manufactured, either for an axial or a mixed flow arrangement.

[0065] In the first configuration, being the mixed flow arrangement, forward hub section 18 and rear hub section 20 are fixed together and the plurality of blades 16 are fitted and then secured in the desired alignment within the sockets 26. The impeller 10 is now in the first configuration.

[0066] In the second configuration, the same or substantially the same, cast hub arrangement 14 may be used - however, the once the forward hub section 18 and rear hub section 20 are fixed together and the plurality of blades 16 are fitted, the shroud arrangement 30 is also fitted. The impeller 10 is now the second configuration being a mixed flow arrangement. The forward and rear shroud sections 32, 34 may be formed, at least in part from sheet metal.

[0067] The forward and rear shroud sections 32, 34 are removably bolted, or otherwise fixed, to the respective forward and read hub sections 18, 20 and the respective locators 42, 48 therefore assist to connect the forward and rear shroud sections 32, 34 and provide a contiguous aerodynamic surface for the fluid flow passing over the frustoconical surface 31 of the cast hub arrangement 14.

[0068] It is noted that the locators 42, 48 may not need to be fixed together other than perhaps a light frictional fit which allows the forward and rear shroud sections 32, 34 to be removed and interchanged, if need be. The forward and rear shroud sections 32, 34 also interlock with the blades 16 via the notches 39, 41.

[0069] Figures 13, 14a and 14b shows a second example of an impeller 110 of a fan arrangement 112 in which like numerals denote like parts (i.e. 10, 110). The second example is generally similar to the first example and as such all parts and the method of manufacturing are not again described again here and only the differences to the first example are described in any detail.

[0070] In this example, the cast hub arrangement 114 may be the same, or substantially the same, as the first example described above and the first configuration may therefore be generally similar to the first example. However, the shroud arrangement 130 in this example is configured differently.

[0071] The shroud arrangement 130 includes a forward shroud section 132 and a rear shroud section 134 which like the first example fit together to form a generally tapered aerodynamic surface 133. In this example, only the forward shroud section 132 includes recesses or cut-outs 161 for the blades 116.

[0072] The cut-outs 161 are shaped, in this example being generally U-Shaped to allow adjustment of the blades 116. The rear shroud section 134 does not include apertures or cut outs in this example. However, the rear shroud section 134 may include additional support ribs 162 as best shown in Figure 14b and similar ribs (not shown) may also be provided on the forward shroud section 132.

[0073] It is noted, like the first example the forward shroud section 132 and the rear shroud section 134 are non-structural and may be formed of sheet metal thereby in some examples requiring some reinforcement such as the aforesaid ribbing. The forward shroud section 132 and the rear shroud section 134 may be removably detectable and like the first example may be detachable and retrofittable. The shroud arrangement 130 providing a non-structural aerodynamic surface therefore allowing the common cast hub 114 to be used for both the first and second configurations being an axial fan and a mixed flow fan or impeller, respectively.

[0074] Advantageously, there has been described examples of an impeller of a fan arrangement that is adaptable between a first configuration, to function as an axial flow impeller or fan, and a second configuration, to function as a mixed flow impeller or fan with a surrounding duct. Both of the first and second configuration may share a common cast hub which may be adapted to either of the first and second configurations by change the blades and the addition of a shroud.

[0075] The shroud is generally non-structural and serves to provide a taperedaerodynamic surface when the impeller is in the second configuration. This allows a common hub to be designed for both uses and also may allow existing hubs of axial fans to be converted to mixed flow fans. The shroud is removable and may be removed to convert the fan arrangement back to an axial fan.

[0076] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0077] The reference in this specification to any known matter or any prior publication is not, and should not be taken to be, an acknowledgment or admission or suggestion that the known matter or prior art publication forms part of the common general knowledge in the field to which this specification relates.

[0078] While specific examples of the invention have been described, it will be understood that the invention extends to alternative combinations of the features disclosed or evident from the disclosure provided herein.

[0079] Many and various modifications will be apparent to those skilled in the art without departing from the scope of the invention disclosed or evident from the disclosure provided herein.

Claims

The claims defining the Invention are as follows:

1. A fan arrangement including a common hub and a plurality of blades arranged to radially extend from the hub, the fan arrangement being configurable or convertible to provide: a. a first configuration in which a first set of the plurality of blades are shaped to provide an axial fan; and b. a second configuration in which a shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface extending about the hub and a second set of the plurality of blades are shaped to provide a mixed flow fan.

2. The fan arrangement according to claim 1 , wherein the shroud arrangement includes a forward shroud section and a rear shroud section which when coupled provide the tapered aerodynamic surface.

3. The fan arrangement according to claim 2, wherein at least one of the forward and rear shroud sections include recesses adapted to form apertures through which the plurality of blades extend.

4. The fan arrangement according to claim 2, wherein the forward and rear shroud sections each include recesses adapted to form apertures through which the plurality of blades extend.

5. The fan arrangement according to claim 4, wherein each recess includes a notch shaped to interlock with respective ones of the plurality of blades.

6. The fan arrangement according to any one of claims 2 to 5, wherein each of the forward shroud section and the rear shroud section include corresponding fingers adapted to locate the forward shroud section and the rear shroud section with one another.

7. The fan arrangement according to any one of claims 2 to 5, wherein each of the forward shroud section and the rear shroud section include corresponding fingers adapted to fit with one another.

8. The fan arrangement according to any one of claims 2 to 5, wherein each of the forward shroud section and the rear shroud section includes an inner skirt adapted to attach with the common hub.

9. The fan arrangement according to claim 8, wherein the hub includes a forward hub section and a rear hub section, and wherein the forward shroud section is coupled to the forward hub section via its inner skirt and the rear shroud section is coupled to the rear hub section via its inner skirt.

10. The fan arrangement according to any one of the previous claims, wherein the forward and rear shroud sections are removably coupled to the hub.

11. The fan arrangement according to any one of the previous claims, wherein the common hub is a cast hub.

12. The fan arrangement according to any one of the previous claims, wherein the common hub includes a forward hub section and a rear hub section.

13. The fan arrangement according to any one of the previous claims, wherein the common hub includes sockets and each the plurality of blades includes a spigot receivable by respective sockets.

14. A system to form an axial flow fan and a mixed flow fan from a common hub, the system including: a. a common hub arrangement; b. a plurality of blades arranged to radially extend from the hub; and c. a shroud arrangement fittable to the hub, wherein, in a first configuration, a first set of the plurality of blades are coupled to the common hub arrangement and the shroud arrangement is omitted, the first set of the plurality of blades being shaped to provide the axial flow fan; and,in a second configuration, the shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface extending from the hub and a second set of the plurality of blades are coupled to the common hub arrangement, the second set of the plurality of blades being shaped to provide the mixed flow fan.

15. A method of forming an axial flow fan and a mixed flow fan from a common hub, wherein, to form the axial flow fan in a first configuration the common hub is fitted with a plurality of blades that are shaped to provide an axial flow fan, and, wherein to form the mixed flow fan in a second configuration the common hub is fitted with a different set of the plurality of blades that are shaped to provide the mixed flow fan and a shroud arrangement is fitted to the hub to provide a tapered aerodynamic surface extending from the hub.

16. A method of converting an axial flow fan to a mixed flow fan, the method including: a. Replacing a plurality of blades fitted to a hub of the axial flow fan with a new set of plurality of blades shaped to provide the mixed flow impeller; and b. Fitting a shroud arrangement to the hub to provide a tapered aerodynamic surface extending from the hub.

17. A shroud arrangement for converting an axial flow fan to a mixed flow fan, the shroud arrangement including a first shroud section and a second shroud section which are adapted to couple to a common hub and to one another to provide a tapered aerodynamic surface from which a plurality of blades radially extend.

18. The shroud arrangement according to claim 17, wherein at least one of the forward and rear shroud sections include recesses adapted to form apertures through which the plurality of blades extend.

19. The shroud arrangement according to claim 17, wherein the forward and rear shroud sections each include recesses adapted to form apertures through which the plurality of blades extend.

20. The shroud arrangement according to claim 19, wherein each recess includes a notch shaped to interlock with respective ones of the plurality of blades.

21. The shroud arrangement according to claim 17, wherein each of the forward shroud section and the rear shroud section include corresponding fingers adapted to locate the forward shroud section and the rear shroud section with one another.

22. The shroud arrangement according any one of claims 17 to 21, wherein each of the forward shroud section and the rear shroud section includes an inner skirt adapted to attach with the common hub.

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