AU2016202363B2

AU2016202363B2 - A ventilator for a roof space or the like

Info

Publication number: AU2016202363B2
Application number: AU2016202363A
Authority: AU
Inventors: Vennesa Hawkes-Sabo
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-04-14
Filing date: 2016-04-14
Publication date: 2022-04-28
Anticipated expiration: 2036-04-14
Also published as: AU2016202363A1

Abstract

A ventilator is disclosed for use on a roof, which includes a mount through which air may flow. The mount includes a support structure that locates a shaft centrally to the mount. The ventilator also includes a hood that is mounted on the shaft and is adapted to rotate relative to the mount. The hood includes a plurality of vanes that are configured such that air flow causes the hood to rotate. The ventilator also includes a fan portion with a plurality of blades, configured to rotate with the hood and draw air through the mount when the hood rotates. Typically, the blades connect the hood to the shaft by extending between a lower portion of the hood and a hub that is mounted on the shaft. An outer ring of the hub, the blades and the hub may be formed as a single component. [Fig. 5] 5/5 15 22 32 14- - 25 33 26 16 FIG. 5

Description

5/5

15

22

32 14- - 25

33 26 16

FIG. 5

A VENTILATOR FOR A ROOF SPACE OR THE LIKE FIELD OF THE INVENTION

[0001] The present invention relates to ventilators and in particular, to wind/air flow powered ventilators that draw air from a duct, roof space or the like.

BACKGROUND

[0002] Wind/air flow powered ventilators are known devices, typically used on roofs of buildings to increase ventilation to attic spaces. In the case of industrial spaces they may be used to increase ventilation to the interior of the building.

[0003] In one example situation, sunlight heating the roof of a building may cause the air immediately inside the roof space to be heated above the ambient outside temperature. The ventilator typically cools the building by drawing out this interior air, which is replaced by ambient outside air that is drawn into the space at some other location (e.g. via a vent).

[0004] Broadly speaking, conventional ventilators generally comprise a rotating hood with a series of vanes that allow an external wind or air flow to drive rotation of the hood. The hood draws air through a duct or opening located below the hood. These conventional ventilators, while providing some benefit, are generally inefficient, expensive, heavy and difficult to install correctly.

[0005] Some existing ventilators include a fan to assist with drawing the air out of the roof space. When installed, the fan is suspended within the roof duct. The closer the periphery fan is to the inner wall of the duct the better the performance will be. However, as the ventilators age, slight changes in alignment often result in the fan contacting the duct, greatly decreasing performance and creating noise.

[00061 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

SUMMARY

[00071 The present invention seeks to provide a ventilator that overcomes some of the disadvantages of the conventional/prior art ventilators and/or provides improved performance over existing designs.

[0008] According to one example aspect, there is provided a ventilator for mounting to a roof duct or the like, the ventilator including a mount through which air may flow. The mount includes a support structure that locates a shaft centrally to the mount. The ventilator

also includes a hood that is mounted to the shaft and is configured to rotate relative to the mount. The hood includes a plurality of vanes. The ventilator also includes a fan portion with a plurality of blades that extend between an inner wall of the hood and a hub that is mounted on the shaft. The fan portion is a unitary structure with both the hood and the hub, whereby the fan portion is configured to rotate with the hood.

[0009] Typically, the vanes are configured such that an air flow causes the hood to rotate.

[0010] In one form, the fan portion is configured to draw air through the mount when the hood rotates.

[0011] In another form, the blades of the fan portion extend between an inner wall of the hood and a hub that is mounted on the shaft. In one form, a base ring of the hood, the blades and the hub are formed as a single component.

[0012] In a further form, the vanes extend between a base portion of the hood and a top cap, the vanes being angled such that they have an inner edge and an outer edge Typically, the vanes include a lip at the outer edge. The lip is typically a rounded groove extending along the outer edge. In another form, the vanes include a lip at the inner edge. This lip may also be a cup shaped groove, however either lip may take any other suitable shape.

[00131 In another example form, the vanes are curved. In one form, the vanes are curved along their length from the base portion of the hood to the top cap. In yet another form, the vanes are curved along their width from the inner edge to the outer edge.

[0014] In other particular, but non-limiting, example forms: the ratio of a maximum gap between vanes to a maximum vane width between the inner and outer edges is above 0.35; the vanes are individually removable; and/ or the shaft is fixed relative to the support structure.

[0015] In a further form, the fan portion is located substantially within the hood. For example, the fan potion may be located within the hood between the top cap and the mount.

[00161 In one form, the solidity ratio of the fan portion is below 0.35, however it will be appreciated that many other solidity ratios may be suitable. In another form, the vanes may be fixed to the hood (e.g. between the top cap and base ring) under flexion.

[00171 In a further form, the vanes and/or other parts of the ventilator are made of a flexible resilient material. In one form, the ventilator is primarily made from a polymer material. In one form, the vanes are fixed to the hood under flexion.

[00181 In one form, the mount is configured to be mounted to a roof duct or other like structure.

[0019] In a further broad form the present invention provides a a ventilator for ventilating of a roof space or the like, the ventilator including: a mount configured to be mounted to a roof duct or the like, the mount having an aperture through which air may flow, the mount also including a support structure to locate a shaft centrally within the aperture; a hood mounted to the shaft and configured to rotate with respect to the mount, the hood including a plurality of vanes; and a fan portion that includes a plurality of blades, the fan portion configured to rotate with the hood.

[0020] In one form, the mount includes a substantially ring shaped main body with a support structure extending into the aperture defined by the ring shaped main body, the shaft being located substantially perpendicular to the plane of the ring shaped main body.

[0021] In one form, the hood includes a base ring and top cap, the vanes extending between the base ring and top cap.

[0022] In another form, the fan portion is located within the hood, between the mount and top cap.

[00231 In a further form, the vanes are formed of a flexible resilient material. In one form, the vanes are formed of a polymer material.

BRIEF DESCRIPTION OF FIGURES

[00241 Example embodiments should become apparent from the following description, which is given by way of example only, of at least one preferred but non-limiting embodiment, described in connection with the accompanying figures, wherein:

[0025] Figure 1 illustrates a perspective view of one example of a ventilator according to the invention;

[0026] Figure 2 illustrates a top view of the ventilator of Figure 1;

[00271 Figure 3 illustrates a side view of the ventilator of Figure 1;

[0028] Figure 4 illustrates a bottom view of the ventilator of Figure 1; and

[0029] Figure 5 illustrates a perspective view of the inside of the ventilator of Figure 1 after some vanes have been removed.

DETAILED DESCRIPTION

[0030] The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

[0031] In the figures, incorporated to illustrate features of an example embodiment, like reference numerals are used to identify like parts throughout the figures.

[0032] Referring to Figure 1, a wind/air flow powered ventilator 10 is shown that includes a hood 12 comprising a plurality of vanes 13 extending from a base ring 14 at a lower portion of the hood 12 to a cap 15 near the top of the hood 12. The hood 12 is connected to a mount 16 such that it can rotate with respect to the mount. Typically the hood rotates about the mount 16 which is fixed to a duct or opening in a roof.

[0033] Referring to Fig. 4 and Fig. 5, the hood 12 is mounted on a shaft 18 that defines an axis 19 (see Fig. 3) about which the hood 12 rotates. The mount 16 includes a support structure 22 for connecting the mount 16 to the shaft 18 and supporting the shaft 18 in a central region of the mount 16. The mount is substantially ring shaped with the support structure provided by radial arms extending to a central body which engages the shaft.

[00341 In the present embodiment, the shaft 18 is fixed to the support structure 22 and therefore fixed against rotation. It will be appreciated the support structure 22 is designed in such a way that it provides minimal resistance to the flow of air through the mount 16.

[0035] A fan portion 30 is located inside a lower part of the hood 12 and includes a plurality of blades 32. These blades 32 connect the hood 12 to the shaft 18 by extending from an inner wall of the base ring 14 of the hood 12 to a hub 33 that is mounted on the shaft 18 using a bearing. Therefore, the blades 32 rotate with the hood 12 and facilitate air flow through the mount 16 as the hood 12 rotates.

[00361 The blades 32 are dual purpose, having the additional advantage of being structural members for the hood, thus removing the need for separate members to connect the hood 12 to the shaft 18. Often, in conventional ventilators, additional structural members are required, adding to the complexity and weight of the hood. In the present embodiment, the base ring 14, fan blades 32 and hub 33 are of unitary construction, being moulded as a single piece. It will be appreciated that in other forms this may not be the case.

[00371 Generally during use, an external wind causes the hood 12 to rotate. For example, referring to Fig. 2, if one considers a wind that blows from the top of the page to the bottom, as shown by arrows 100, the vanes 13 on the left hand side of the figure may be considered on the "downstream" side 105, and would typically tend to "catch" the wind, creating drag and moving in a direction with the wind. Similarly, the vanes 13 on the right hand side would typically largely deflect the wind, providing less drag and moving against the wind, or in an "upstream" direction 106. This operation may be in some ways similar to the operation of a cup anemometer. It will be appreciated that the overall rotation of the hood 12 is shown by arrow 110, and is the same regardless of the wind direction.

[00381 The ventilator described herein provides for far simpler mounting to a roof duct when compared to the conventional prior art ventilators. The mount 16 includes an outer wall 25 and a duct mounting flange 26 with optional duct mount holes 28. When installed on a duct opening, the outer wall 25 simply fits over the outside of the rim of the duct and the flange 26 abuts the end. The ventilator thus sits over the duct opening. This allows for simple sealing and securing, and allows for some tolerance with regard to alignment and positioning of the ventilator.

[00391 As shown in Fig. 5, the fan 30 is located on the hood 12 side of, or above, the support structure 22. In one sense, this may be considered to be inside the hood 12. This allows the support structure 22 to provide a level of protection to the fan blades 32 prior to the installation of the ventilator 10. The attachment of the fan blades 32 to the base ring 14 also means that they are well supported and cannot become bent or misaligned.

[0040] As described above, it is the fan blades 32 themselves that connect the hub 33 to the base ring 14. This is an advantageous feature of the design shown, as there is no gap between the outside of the fan blades 32 and the base ring 14.

[0041] In conventional ventilators, the fan is sometimes located below the support structure to be suspended inside the duct. This results in a gap at the periphery of the fan and requires precise alignment during installation to avoid contact between the fan and the inner wall of the duct. In the ventilator as described in herein, the fan sits above the mount 16, and thus the danger of the fan contacting the inner wall of the duct is removed.

[0042] The location of the fan blades 32 within the hood 12 and above the support structure 22 reduces the likelihood of the fan 30 being misaligned before installation or contacting the inner wall of the duct after installation. As noted above, this is a common issue with conventional ventilators, which may be due to rough handling before installation, poor installation or movement over time caused by corrosion, weather and other impacts such as from wildlife. As noted previously, contact of the fan with the inner duct wall in conventional ventilators can reduce performance and may result in significant noise during operation.

[00431 The fan 30 shown in the figures has six relatively narrow blades, resulting in a low solidity ratio. The solidity ratio is the ratio of the plan area of the blades 32 in relation to the total swept area of the fan 30. Alternative embodiments may use any other number of blades of widely ranging widths and shapes.

[0044] The example shown has a solidity ratio of approximately 0.3. In alternative embodiments any other ratio may be used, however a ratio below 0.5 is preferred, between 0.2 and 0.4 is more preferable, and between 0.25 and 0.35 is most preferable.

[00451 The low solidity ratio of the fan 30 reduces material requirement, lowers weight and may improve fan performance under some operating conditions. The low solidity ratio may also improve the performance of the ventilator 10 in the absence of external wind.

[0046] It is suggested that in some prior art/conventional designs the high solidity of the fan produces significant resistance to air flowing through the ventilator under natural convection alone, which may, for example, result from heat naturally flowing up the inside of a heated roof (work is done turning the hood, thereby reducing the flow rate). However, in the presently described ventilator, this resistance may be reduced, potentially lowering the rotation of the hood 12 in still conditions, but providing an overall increased flow rate of air.

[00471 Referring to Fig. 1, the vanes 13 extend between the top cap and base ring of the hood and are curved along their elongate length such that the hood has a rounded shape. The vanes 13 are also angled so that they have an inner (or trailing) edge 51 towards the inside of the hood 12 and an outer (or leading) edge 50 towards the outside of the hood 12. The vanes 13 include an outer lip 34 on this outer edge and an inner lip 35 on this inner edge. The outer lip 34 extends substantially along the length of the outer edge. The outer lip 34 typically has substantially curved profile so as to provide be a rounded groove extending along the outer edge of the vane. It will be appreciated however that the lip may take a variety of forms.

[00481 Referring to figure 2 with the concave or inner face of the lip facing into the wind on the "downstream" side 105, the lip typically serves to catch the wind on the "downstream" side 105. The back or convex part of the lip 34 facing away from the wind on the "upstream" side 106.

[0049] Without wishing to be bound by theory, it is proposed that the addition of the lip 34 provides an increase in torque on the downstream side 105 that exceeds any increase in drag from the upstream side 106, resulting in an increased net torque produced by the shape of the vanes 13. It is also proposed that the deflection of the wind by the lip 34 on the upstream side 106 may help to create a low pressure zone that increases the drawing of air out from the inside of the hood 12.

[0050] Typically the inner lip 35 has a similar curved profile to the outer lip 34. The inner lip 35 may also aid the extraction of air from the inside of the hood 12, assisting the operation of the fan 30. As yet a further advantage, the outer lip 34 and the inner lip 35 both contribute to the strength of the vane 13. For example, variations in the shape of the inner 35 and outer 34 lips may be used in alternative embodiments to adjust the degree of resilience and/or strength of the vanes 13.

[0051] It may be considered that the rotation of the hood 12 causes the vanes 13 to work in a similar way to an impeller of a centrifugal pump, drawing air from the inside to the outside of the hood 12 and in turn assisting the fan 30 to draw air through the mount 16.

[0052] In the presently shown embodiment the main portion 37 of the vanes 13 is curved from the leading edge to the tailing edge, as shown in Fig. 2. Figure 2 only shows a slight curve, however it will be appreciated that the curve may vary in alternative embodiments. This curve of the main portion 37 may allow for more efficient movement of air, especially when compared to the straight/planar vanes that are often used in the prior art.

[00531 Again, without wishing to be bound by theory, it is proposed that the shape of the vanes 13 can provide a compromise with the overall backward curve of the main portion 37 improving movement of air from inside to outside the hood 12, and the lips 34, 35 on the edges increasing the rotation of the hood 12 caused by any external wind.

[0054] In the embodiment shown in the figures, the ratio of a maximum gap 40 between vanes 13 to a maximum vane width 42 is about 0.4. In alternative embodiments any other ratio may be used, however a ratio above 0.2 is preferred, between 0.3 and 0.5 is more preferable, and between 0.35 and 0.45 is most preferable.

[0055] The gap 40 in the current embodiment is a relatively large gap and means that the vanes 13 have a high angle of attack.

[00561 Preferably, the ventilator 10 is primarily made from a flexible and resilient material, such as a synthetic polymer. Example materials may include polyvinyl chloride (PVC) or high-density polyethylene (HDPE). The embodiment shown in the figures uses parts mostly made from a plastic/polymer that are then secured to one another using screws 45, although any other suitable fastener may be used. This allows the option for simple disassembly, including removing vanes 13 individually, and/or supply as a "flat pack" for home assembly. Typically, at least the vanes are formed of a flexible resilient material.

[00571 Due to the overlapping of the vanes 13 at the top of the hood 12, fewer screws 45 are used for attaching the vanes 13 to the cap 15, but each vane 13 is still attached in two places, as each screw 45 extends through two vanes 13.

[00581 Advantages to the use of flexible resilient materials (e.g. plastics/polymers) for the construction of the parts of the ventilator include lower noise due to the dampening properties of the material, cheap construction, light weight, durability both prior to and after installation, and lowered risk of injury to technicians during installation from cuts on sharp edges. For example, use of resilient materials means that prior to installation if the ventilator 10 is knocked or dropped, the vanes will simply bend and then return to their original shape, rather than being permanently dented. In some examples, the vanes are secured between the base ring and top cap under flexion.

[0059] The use of such materials (e.g. polymers/plastics) thus allows for far greater flexibility in the design of the various components. Some components, such as the vanes 13 for example, can have shapes and variations in thickness that may not be feasible in a sheet metal design.

[00601 The lower section of the hood 12 including the base ring 14, the fan blades 32 and the hub 33 are typically formed as a single piece. This reduces weight by removing the need for fasteners and provides support to the hood 12. The hub 33 may form the only connection of the hood 12 to the shaft 18, however in the embodiment shown, the shaft 18 extends through to the cap 15 where it also attaches using a bearing.

[00611 In an alternate embodiment, it will be appreciated the shaft 18 may be fixed to the hood 12 and rotate relative to the support structure 22.

[0062] Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

[00631 Throughout this specification, specific terminology has been resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "top" and "bottom", "inner" and "outer", "above" and "below", "upper" and "lower" and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms. The terms generally refer to the orientation as shown in Figures 1 and 3, however the invention may be oriented at other angles in use.

[0064] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "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.

[0065] List of parts:

Ventilator 32 Fan blades 12 Hood 33 Hub 13 Vane 34 Outer lip 14 Base ring 35 Inner lip Cap 37 Main portion of a vane 16 Mount 40 Gap between vanes 18 Shaft 42 Vane width 19 Shaft axis 45 Screw 22 Support structure 50 Outer edge of vane Outer wall of mount 51 Inner edge of vane 26 Duct mounting flange 100 Wind direction 28 Duct mount holes 105 Downstream side Fan 106 Upstream side 110 Rotation direction

Claims

The claims defining the invention are as follows:

1. A ventilator for mounting to a roof duct or the like, the ventilator including: a mount through which air may flow, the mount including a support structure that locates a shaft centrally to the mount; a hood mounted to the shaft and configured to rotate relative to the mount, the hood including a plurality of vanes; and a fan portion including a plurality of blades that extend between an inner wall of the hood and a hub that is mounted on the shaft, the fan portion being a unitary structure with both the hood and the hub, whereby the fan portion is configured to rotate with the hood.

2. A ventilator as claimed in claim 1, wherein the vanes are configured such that an air flow causes the hood to rotate.

3. The ventilator according to claim 1, wherein the fan portion is configured to draw air through the mount as the hood rotates.

4. The ventilator according to any one of the preceding claims, wherein the vanes, extend between a base portion of the hood proximal to the mount, and a top cap.

5. The ventilator according to any one of the preceding claims, wherein the vanes are angled having an inner edge and an outer edge, one or both of the inner edge and/or the outer edge of the vanes defining a lip thereat.

6. The ventilator according to claim 5, wherein the lip at the outer edge is a rounded groove extending along the outer edge.

7. The ventilator according to any one of claims 5 or 6, wherein the vanes are curved along their length from the base portion of the hood to the top cap.

8. The ventilator according to any one of claims 5 to 7, wherein the vanes are curved along their width from the inner edge to the outer edge.

9. The ventilator according to any one of claims 5 to 8, wherein the ratio of a maximum gap between vanes to a maximum vane width between the inner and outer edges is above 0.35.

10. The ventilator according to any one of the preceding claims, wherein the vanes are individually removable.

11. The ventilator according to any one of the preceding claims, wherein the shaft is fixed relative to the support structure.

12. The ventilator according to any one of the preceding claims, wherein the fan portion is located substantially within the hood.

13. The ventilator according to any one of the preceding claims, wherein a solidity ratio of the fan portion is below 0.35.

14. The ventilator according to any one of the preceding claims, wherein a base ring of the hood, the blades and the hub are formed as a single component.

15. The ventilator according to any one of the preceding claims, wherein the vanes are made of a flexible resilient material.

16. The ventilator according to any one of claims 4 to 15, wherein the fan portion is located within the hood, between the top cap and the mount.

17. The ventilator according to any one of the preceding claims, wherein the vanes are fixed to the hood under flexion.

18. The ventilator according to any one of the preceding claims, wherein the mount is configured to be mounted to a roof duct or the like, the mount having a substantially ring shaped main body with a support structure extending into an aperture defined by the ring shaped main body through which air may flow, the shaft being located substantially perpendicular to the plane of the ring shaped main body.

19. The ventilator according to any one of the preceding claims, wherein the ventilator comprises a polymer material.