AU2002301161B2

AU2002301161B2 - Turbine ventilator

Info

Publication number: AU2002301161B2
Application number: AU2002301161A
Authority: AU
Inventors: Lee Blattman
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-10-12
Filing date: 2002-09-24
Publication date: 2008-01-17
Anticipated expiration: 2022-09-24

Description

AUSTRALIA

Patents Act 1990 GABRIEL ANDREWS COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Turbine ventilator The following statement is a full description of this invention including the best method of performing it known to us:- 2 Field of the Invention SThis invention relates to a roof ventilator, and in particular to a type of roof ventilator known as a turbine roof ventilator.

Background of the Invention During the summer, in hot countries such as Australia, large amounts of heat

INO

from the sun's rays enter houses through their roof tops and heat up the attic space or roof chamber beneath the roof of the house. In some cases the temperature in the roof chamber can rise to up to 700 C and the temperature inside the house will consequently increase. To address this problem, it is known to install turbine roof ventilators to ,IC extract air from roof chambers which work on the well known principle that hot air rises, and which allow hotter air to escape from the roof chamber before the temperature of the air in the roof chamber rises excessively. During the winter, roof ventilators also help keep houses dry, remove shower and kitchen steam, keep insulation dry and thus help prevent mould and mildew growth.

Turbine roof ventilators comprise a rotatable sleeve on the top end of which is mounted a rotatable turbine wheel or hood. The turbine hood includes a closed circular, usually convex upper end which prevents ingress of rain into the sleeve and thus into the roof chamber, a lower ring and a series of arcuate turbine blades extending from the lower ring to the upper end through which hot air flows. The turbine blades can rotate either due to winds or breezes, or due to the flow of air from out under the roof through the turbine.

Although turbine roof ventilators work, several such devices may be required for even quite small roofs.

It is an object of the present invention to provide improvements to turbine roof ventilators which increase their efficiency and usefulness.

Summary of the Invention In a first aspect of the present invention there is provided a turbine roof ventilator including: a rotatable shaft defining a first, or upper end, and a second end or lower end defining a longitudinal axis; a turbine hood including a closed upper end, a lower ring disposed below the upper end and a series of blades extending from the lower ring to the upper end defining gaps therebetween, the hood being mounted on the upper end of the shaft and arranged to turn with the shaft; 3

O

a sleeve member through which air may flow disposed below the turbine hood, the sleeve member being fixed in use; a bearing housing supporting the shaft for rotation about the longitudinal axis of the shaft, the bearing housing being mounted to the sleeve member by means of at least three arms which extend from the bearing housing to the sleeve member; a fan or the like adapted to turn with the turbine hood or shaft so that as the turbine hood turns the fan blows or sucks air through the sleeve up towards the hood to improve the rate of flow of air through the roof ventilator; and means, such as a differential means, for causing the fan or the like to rotate at a greater angular velocity than the turbine hood.

C, Causing the fan to turn at a greater velocity to the hood improves the flow of air through the ventilator. Thus, even on days when the hood turns slowly, the fan provides improved ventilation.

In one embodiment, the differential means may include an epicyclic gearbox.

The planet carrier of the gearbox may be fixed to the shaft, the sun gear locked, and the planet carrier connected to the fan, thereby causing the fan to rotate at a greater speed than the turbine hood.

In an alternative embodiment, a motor, typically a solar powered electric motor may comprise the differential means.

Typically, the interior portion of the blade includes a scoop portion which when the turbine is caused to rotate in one direction about its axis of rotation is adapted to scoop air upwards into the turbine hood and in conjunction with a ceiling direct the air through the gaps between the turbine blades.

In a preferred feature the turbine hood includes one or more ribs on the outer portion of the blade to assist the outer portion to catch air currents.

In one particular embodiment there may be three ribs. The ribs are preferably located close to the outer edge of the outer portion of the blade.

The blades may be a flattened S-shape having a thickened portion between the outer concave and inner portions by means which the blade is attached between the cover and a base portion of the turbine hood.

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

Brief Description of the Drawings Specific embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which:- Figure 1 is a schematic view of a first embodiment of a turbine roof ventilator; Figure 2 is a schematic view section through the roof ventilator of Figure 1; and Figure 2a shows an epicyclic gear box.

Detailed Description of the Preferred Embodiments Referring to the drawings, Figure 1 shows a schematic view of a turbine roof ventilator 10 embodying the present invention. The roof ventilator includes a turbine hood or rotor head 12 which is mounted on a shaft 14. The shaft 14 is rotatably mounted in a bearing housing 16 on upper bearings 18 and lower bearings 20. The upper and lower bearings are preferably made of steel having a steel inner ring and a steel outer ring separated by a race of ball bearings. The shaft extends upwardly beyond the upper bearings 18 as far as the top of the turbine hood.

Four arms 22 extend away from the bearing housing in a cruciform configuration to support the bearing housing and turbine hood above a cylindrical sleeve 24 through which hot air is to be drawn, in use.

The turbine hood 12 includes a roof or cover portion 26, a lower ring 28 and a series of blades 30 typically about twenty-four in number, which extend between the cover portion 26 and the lower ring 28. At the base of each blade there is a depending projection 32 which snap fits into a corresponding recess 34 in the lower ring. At the top of each blade there is a projection 36 which extends in a sideways direction which snap-fits into a corresponding recess 38 in the cover portion 26. A series of six spokes or arms 40 extend from lower ring to the shaft 14 for supporting the lower ring 28 for rotation with the shaft about the longitudinal axis 14a of the shaft. The cover portion 26 includes a series of curved ribs 42 which include a first arcuate portion 42a which extends from the shaft 14 through an angle of 90 degrees and an integral, relatively short, straight portion 42b which extends towards the perimeter of the cover portion 26. A curved ceiling 44 whose shape corresponds to the surface of revolution obtained when the rib 42 is rotated 360 degrees around the longitudinal axis 14a of the shaft extends from the shaft 14 to the perimeter of the cover 26. The ceiling 44 is supported by the ribs 42, typically four in number. The ceiling 44 provides a barrier against the flow of air. The shape of the ceiling is such that such that air flowing up through the middle of the ventilator tends to flow up and along the ceiling radially of the shaft along a path shown by the arrows marked A, and out through gaps between adjacent blades of the turbine hood (see figure 2).

The blades 30 are curved in section (see Figure 2) and have a tip portion which is almost tangential to the circumference of the turbine hood. The tip portion defines two projections or ribs 50 which extend along the length of the blade (see Figure 1) and assist the blades in catching wind and air currents, for turning the hood in the direction B. The blades are also curved along their length as is best seen in Figure 1 so that the turbine hood is generally rounded.

At the base of the turbine hood below the blades there is a series of scoop blades 52 which project inwardly towards the shaft. Figure 1 shows a quarter of the ring of scoop blades. The scoop blades are angled at about 120 degrees or so to the direction of air flow through the sleeve 24. The blades are also slightly curved in cross-section. There are around eighteen scoop blades in total. As the turbine hood rotates the lower ring and scoop blades also rotate. They encourage air flow and have the effect of pushing the air upwards and when the air contacts the ceiling it is directed along the ceiling and outside the turbine hood. The above arrangement provided an efficient flow of air through the turbine with no dead spots where air can become trapped.

With reference to Figure 2 in particular, extraction of air through the sleeve is further improved by a fan/impeller/propeller assembly generally indicated at 53, comprising a number of planar fan blades or vanes 54. The vanes extend between a central block 56 mounted on the bottom of the shaft 14 to an outer ring 58. A series of spokes 59 also extend between the central block and the outer ring 58. A cylindrical rod like projection 60 is defined on the outer edge of the blade which locates in a cylindrical recess in the outer ring 58. A similar rod 62 projects from the inner edge of the blade and locates in a recess in the central block. An arm 64 extends from each rod 62. The vanes are mounted by means of the rods 60 and 62 so that'they can be can be tilted about an axis defined by the rods. The arms 64 are all operatively connected to a control knob 66 mounted on the bottom of the shaft and turning of the knob causes the arms to move about the axis of the rods and thus turns the blades about that axis. The blades may all be oriented so that all the blades are all coplanar and oriented generally perpendicularly to the sleeve in which orientation the edges of the vanes abut the spokes and the fan closes off the sleeve inhibiting the flow of air through the roof ventilator. This also prevents the ingress of rain and the like. Alternatively the vanes 54 may be angled or raked so that as the fan 53 rotates about the shaft 14 it increases the flow of air through the turbine hood.

Projecting ribs 68 are provided on the top of the hood to catch the wind.

The top of the hood 26 is either made of a transparent material or may define transparent windows. A shelf 69 is provided below the top. In one embodiment, a number of solar panels 70 are mounted on the shelf used to supply power to a motor 72 for turning the fan assembly 53 on windless days.

The motor may also be arranged to turn the shaft 14 and turbine hood.

In an alternative embodiment, the motor 72 is replaced by an epicyclic gearbox 100 comprising a sun gear 102, one or more, typically three, planetary gears 104 mounted on a planet carrier 106, and an annulus gear 108.

In order to make the fan 53 rotate at faster speed than the turbine hood, the planet carrier 106 is fixed to/driven by the shaft 14 and rotates at the same angular speed as the shaft, the sun gear 102 is locked (prevented from turning) and the fan fixed to the annulus gear 108 for rotation at the same angular speed as the annulus gear which turns at a faster rate than the planet carrier and therefore faster than the shaft/hood. Alternatively, the annulus gear 108 may be locked, the planet carrier 106 connected to the shaft 14 and the sun gear 102 to the fan 53. Again, in this arrangement, the fan will rotate at a faster rate than the hood.

Apart from the shaft 14 and the bearings and a number of the components such as screws, gears, and the like, most of the components may be made out of moulded polycarbonate, although other suitable materials could be used.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the 7 specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

2. A turbine roof ventilator as claimed in claim 1 wherein the means for causing the fan or the like to rotate at a greater angular velocity than the turbine hood, includes gearing.
3. A turbine roof ventilator as claimed in claim 1 or claim 2 wherein the means for causing the fan or the like to rotate at a greater angular velocity than the turbine hood, is an epicyclic gearbox.
4. A turbine roof ventilator as claimed in claim 3 wherein the epicyclic gear box includes a planet carrier, sun gear and an annulus gear and wherein the planet carrier is fixed relative to the shaft, the sun gear is locked, and annulus gear is connected for rotation with the fan. A turbine roof ventilator as claimed in claim 3 wherein the epicyclic gear box includes a planet carrier, sun gear and an annulus gear and wherein the annulus gear is locked, the planet carrier is fixed for rotation with the shaft and the sun gear is fixed for rotation with the fan.
6. A turbine roof ventilator as claimed in claim 1 or claim 2 wherein the means for causing the fan or the like to rotate at a greater angular velocity than the turbine hood, includes a motor. 9
7. A turbine roof ventilator as claimed in any preceding claim wherein an interior Sportion of the blade includes a scoop portion which when the turbine is caused to rotate C in one direction about its axis of rotation is adapted to scoop air upwards into the turbine hood and in conjunction with a ceiling direct the air through the gaps between the turbine blades.
8. A turbine roof ventilator as claimed in any preceding claim wherein the turbine hood includes one or more ribs on an outer portion of the blade to assist the outer portion to catch air currents. c 9. A turbine roof ventilator as claimed in claim 8 wherein each blade defines two ribs located close to an outer edge of the outer portion of the blade. ,I 10. A turbine roof ventilator as claimed in any preceding claim wherein the fan is mounted in the sleeve at the second, lower, end of the shaft.
11. A turbine roof ventilator as claimed in any preceding claim wherein the fan is spaced from the turbine hood.
12. A turbine roof ventilator substantially as hereinbefore described with reference to the accompanying drawings.