AU2813499A

AU2813499A - Roof ventilator

Info

Publication number: AU2813499A
Application number: AU2813499A
Authority: AU
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-10
Filing date: 1999-05-13
Publication date: 1999-10-07
Anticipated expiration: 2005-03-10
Also published as: AU730439B3

Description

AUSTRALIA

Patents Act 1990 GABRIEL ANDREWS

ORIGINAL

COMPLETE SPECIFICATION DIVISIONAL PETTY PATENT Invention Title: Roof ventilator The following statement is a full description of this invention including the best method of performing it known to us:r r 2 Field of the Invention This 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 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 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 25 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 an improved turbine roof ventilator.

Summary of the Invention According to the present invention, there is provided a turbine roof ventilator including: i a rotatable shaft defining a first, or upper end, and a second end; a turbine hood mounted on the upper end of the shaft and adapted to turn with the shaft; I 3 a sleeve member through which air may flow disposed below the turbine hood; means for mounting the shaft relative to the sleeve member whilst allowing the shaft to turn about its longitudinal axis; and a fan or the like disposed on the shaft generally below the turbine hood and adapted to turn with the shaft so that as the turbine hood turns the fan blows or sucks air through the sleeve to improve the rate of flow of air through the roof ventilator.

Tests have shown that the use of a fan, vane assembly, airscrew, paddle wheel, propeller or equivalent device in addition to the normal turbine hood can double the rate of flow through the roof ventilator and thus improve the performance of the roof ventilator and lower the temperature in a roof chamber compared with existing roof ventilators. This also allows satisfactory cooling of roof chambers with fewer ventilators and hence lower installation costs.

In a preferred embodiment, the shaft is mounted to the sleeve by means of at least three, preferably four, arms which extend from a bearing housing in which the shaft is mounted to the cylindrical sleeve of the roof ventilator.

The housing arms may be made of solid filled glass fibre and may include a strengthening rib.

:Brief Description of the Drawings Specific embodiments of the invention will now be described, by way 25 of example only, and with reference to the accompanying drawings in which: Figure 1 is a schematic drawing of a first embodiment of the present invention; Figure 2 is a perspective view of a turbine hood; and Figure 3 is a plan view of a fan blade assembly.

Detailed Description of Preferred Embodiments Referring to the drawings, Figure 1 shows an embodiment of a turbine roof ventilator 10 embodying the present invention. The turbine roof ventilator 10 includes a one piece shaft 12 having a 10mm outside diameter.

The shaft is preferably made of steel or aluminium. A turbine hood or wheel 14 is mounted on the upper half of the shaft. The turbine hood is of a r standard design having a domed circular cover 16, a lower turbine centralising ring 18 and a series of arcuate turbine blades or vanes, not illustrated in Figure 1 but shown in Figure 2, extend between the cover 16 and the lower ring 18. The lower ring 18 comprises an inner ring disposed about the shaft 12, an outer ring and a series of spokes extending from the inner ring to the outer ring which locate the outer ring but allow the passage of air through the centralising ring.

The turbine hood is secured to the shaft by means of two washers 22 disposed either side of the cover 16 and a dome nut 24 screwed onto the threaded upper end of the shaft 12. A sleeve 25 fits over the shaft between the cover and lower ring 18. (The sleeve has a 1.lmm inside and a 12.7mm outside diameter). Below the lower turbine centralising ring 18 there is a annular cylindrical sleeve 27 through which air passes when the turbine roof ventilator is installed on a roof. The lower half of the shaft defines a bearing housing 26. The bearing housing carries an upper bearing 28A and a lower bearing 28B.

Four solid filled glass fibre housing arms 29 in a cruciform arrangement are integral with the bearing housing. Each housing arm includes a strengthening rib 30 and a depending leg 32 defined at the extreme end of each arm which defines a screw hole 34 for attaching the arm to the cylindrical sleeve 27 and to a cylindrical hole in a roof thereby fixing the bearing housing and the shaft relative to the sleeve. Above the bearing housing, there is a felt washer 36 approximately 40 to 50mm diameter with a 13mm central hole which is adapted to prevent entry of foreign matter into 25 the bearings. The bearings are preferably made of steel having steel inner ring and steel outer ring separated by a race of ball bearings. A sleeve 38 of the same cross section as sleeve 25 is disposed around the shaft between the upper and lower bearings.

A fan blade assembly 40 is disposed at the lower of the shaft. When 30 the shaft rotates, the fan blades also rotate and thereby push air into the cylindrical sleeve and up through the turbine hood.

The fan blade assembly, best seen in Figure 3, includes a central "1circular portion 42, a step or indented portion 44 to improve the strength of the blade assembly an adjacent annular ring 46 and a series of angled blades 48 disposed around the periphery of the central portion. The blade may be stamped out from aluminium or steel sheet or may be made of another suitable material such as plastic.

A sleeve spacer 50 is fitted on the body of the shaft below the bearing housing and the above blade assembly is fitted below that spacer by means of a threaded lock nut 52 It is important that the fan blades are precisely fitted on the shaft with the blades centred on the shaft without any free play in the fitting.

In use, when the turbine hood 16 turns, for example, due to wind or air currents, the fan also turns pushing hot air up through the ventilator and out through the hood increasing the air flow through the ventilator.

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 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.

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Claims

1. A turbine roof ventilator including: a rotatable shaft defining a first, or upper end, and a second end; a turbine hood mounted on the upper end of the shaft and adapted to turn with the shaft; a sleeve member through which air may flow disposed below the turbine hood; means for mounting the shaft relative to the sleeve member whilst allowing the shaft to turn about its longitudinal axis; and a fan or the like disposed on the shaft generally below the turbine hood and adapted to turn with the shaft so that as the turbine hood turns the fan blows or sucks air through the sleeve to improve the rate of flow of air through the roof ventilator.

2. A turbine roof ventilator as claimed in claim 1 wherein the shaft is rotatable in a bearing housing which is mounted to the sleeve member by means of at least three arms which extend from the bearing housing to the sleeve member.

3. A turbine roof ventilator as claimed in claim 1 or claim 2 wherein the fan is mounted on the lower end of the shaft in use below the bearing housing and wherein the sleeve is cylindrical. o.oo Dated this thirteenth day of May 1999 GABRIEL ANDREWS Patent Attorneys for the Applicant: F B RICE CO