WO1994028269A1

WO1994028269A1 - Venting apparatus

Info

Publication number: WO1994028269A1
Application number: PCT/AU1994/000282
Authority: WO
Inventors: Ean Lawrence Mcdonald
Original assignee: Ean Lawrence Mcdonald
Priority date: 1993-05-26
Filing date: 1994-05-26
Publication date: 1994-12-08

Abstract

A ventilator which is adapted to be received over an elongate slot shape aperture (14) provided in a roof (12) comprising a first cowl (20) which is to be located to each side of the aperture and to be coextensive therewith said first cowl having a first side wall (22) located to one side of the aperture (14), and a second wall (22) located to the other side of the aperture (14) and an end wall at each end interconnecting each side wall, the upper edges (26) of the side walls (22) being spaced from each other above the aperture (14), said first and second side wall (22) being substantially planar and convergent towards each other, where the degree of inclination of the side walls (22) is such that air flowing over the side walls (22) is deflected in a substantially non turbulent manner, said ventilator further comprising a second cowl (30) located between said side walls (22) and beneath the upper edge (26) of said side walls, said cowl overlying the aperture and extending between the end walls of the first cowl, the side edges of the second cowl being spaced above the aperture and being spaced inwardly from the side walls.

Description

"VENTING APPARATUS"

THIS INVENTION relates to roof ventilators.

In the past ventilation of buildings by utilisation of roof ventilators has utilised ventilators of a variety of forms.

One common form of ventilator has comprised utilisation of an upstanding circular duct which is covered at its upper end by a conical cowl. The conical cowl overlies the other upper end of the pipe but is spaced from the upper end to allow for air flow between the upper end and the cowl and the outer edge of the cowl generally extends below the upper end of the duct. While such ventilators can be effective under some conditions they are not effective under all conditions. One significant difficulty with such ventilators comprises the entrapment of warm air between the upper end of the duct and the cowl which creates an air pocket at the upper end of the duct and prevents any further air flow out of the duct. In addition because of their limited size a large number of these vents have to be installed on a roof space to provide for adequate ventilation.

Another form of ventilator which has been utilised in the past has utilised a rotating turbine which is driven by the wind and which is associated with an extractor rotor associated with the vent which on rotation of the turbine actively draws air from the roof space through the duct. These forms of ventilators however are dependant upon the presence of wind in order to effect the ventilation and it is often necessary to maximise ventilation under conditions where no wind is present. As a result such ventilators can have little effect under no wind conditions and can in fact restrict air flow because of the presence of the rotor. The subject of Australian patent specification 440510 is a ventilator which provides a circular cowl located over the upper end of the duct and which is spaced from the upper end of the duct to allow for air flow. The duct is surrounded by an annular second cowl which protects the space between the first cowl and the upper end of the duct from the entry of weather. The second cowl generally has a curved configuration and because of its profile provides a barrier for air flow across the roof space and deflects the air flow over it. Because of the configuration of the second cowl such deflection creates a turbulent air flow over the opening formed in the central part of the second cowl. The creation of this turbulence serves to reduce the degree of air flow from the ventilator that could be generated by such air flow. Furthermore since the ventilator comprises a circular duct, the amount of air flow that can pass through the duct is limited by the dimensions of the duct. In order to provide for adequate ventilation of the space below the roof a large number of ventilators must be applied to the roof.

Another form of ventilator has comprised an elongate housing which is mounted over a slot shaped aperture provided in a roof and which overlie the aperture to provide ventilation. The ventilators are suitably configured to prevent rain and wind from entering the duct under adverse weather conditions. A difficulty with such ventilators however is they provide a barrier to any air flow passing over the roof surface and create turbulence in the region of the opening of the ventilator which restricts the amount of air flow from the ventilator under windy conditions.

It is an object of this invention to provide a ventilator which is able; to cover an elongate aperture provided in a roof; to allow the free flow of air out of the building through the ventilator; to prevent the entry of rain or the like into a building through the ventilator; and which has a structure whereby air flow over the ventilator will enhance air flow from the ventilator.

In one form the invention resides in a ventilator which is adapted to be received over an elongate slot shape aperture provided in a roof comprising a first cowl which is to be located to each^"side of the aperture and to be coextensive therewith said first cowl having a first side wall located to one side of the aperture, and a second wall located to the other side of the aperture and an end wall at each end interconnecting each side wall, the upper edges of the side walls being spaced from each other above the aperture, said first and second side wall being substantially planar and convergent towards each other, where the degree of inclination of the side wall is such that air flowing over the side walls is deflected in a substantially non turbulent manner whereby the air flow over the space between the upper edges is caused to move at an increased velocity to hence produce a greater air flow from the vented space, said ventilator further comprising a second cowl located between said side walls and beneath the upper edge of said side walls, said second cowl overlying the aperture and extending between the end walls of the first cowl, the sideoedges of the second cowl being spaced above the aperture and being spaced inwardly from the side walls.

According to a preferred feature of the invention each side wall comprises a lower and upper planar portion whereby the lower portion has a lesser degree of convergence than the upper portion. According to a preferred feature of the invention the ventilator incorporates a base which overlies the roof to either side of the aperture and is formed with a central

0 opening conforming substantially to the configuration and dimensions of the aperture wherein said first cowl is fixed at its lower edge to the base. According to a further feature the edges of the opening are defined by an upstanding portion which surrounds the aperture. According to a further preferred feature of the invention, the second cowl is supported from said base by an upstanding bracket to each side of the opening. In addition the bracket can support the upper edge of the adjacent side wall.

According to a preferred feature of the invention the ventilator is to be mounted over an aperture provided in the ridge of a pitched roof.

According to a further preferred feature of the invention, a flow control means is provided in association with the opening.

According to a further preferred feature of the invention, the first and second cowl are formed by a metal section whereby the upper edge of each side wall is interconnected with the adjacent side edge of the second cowl by a web having apertures formed therein.

According to a further preferred feature of the invention, the second cowl has an upper and lower face of substantially similar configuration in opposed relation to each other. According to one example the second cowl has a substantially diamond shaped cross section.

According to a further preferred feature of the invention, the second cowl is formed at least partially from a light transmissive material. A further preferred feature provides that the second cowl is formed of a fusible material. The invention will be more fully understood in the light of the following description of one specific embodiment. The description is made with reference to the accompanying drawings of which;

Figure 1 is a sectional elevation of a roof ventilator applied over an aperture provided in a pitched roof;

Figure 2 is a part sectional isometric view of the ventilator of Figure 1;

Figure 3 is a sectional isometric view of a second embodiment of the invention;

Figure 4 is a cross sectional view of a third embodiment of the invention.

Figure 5 is a cross sectional view of a fourth embodiment of the invention.

The first embodiment shown at Figure 1 is directed to a roof ventilator which is to be applied over an aperture formed along the ridge of a pitched roof. The roof 12 comprises a first and second roof panel 12a and 12b which are upwardly convergent when and where for a portion of the ridge formed between the roof panels the upper edges are spaced from each other to define an aperture 14 therebetween. The ventilator comprises a base 16 which is intended to be fixed be to the roof 12 in the region of the aperture 14 such that it overlies the roof panels 12a and 12b to each side of the aperture and is coextensive with the aperture 14. The base 16 is formed with a central opening which is intended to have substantially the same configuration and dimensions as the aperture 14 and which is defined at its edge by an upstanding lip 18. The base 16 supports a first cowl 20 formed by a pair of side walls 22 which are substantially parallel to the sides of the aperture 14 and an end wall (not shown) at each end which interconnects the side walls 22. The side walls are formed at their lower edge with a lower flange 24 which is fixed to the respective side of the base 16. The side walls 22 are substantially planar and each comprise a lower planar portion 2o2a and an upper planar portion 22b the side walls are upwardly convergent however the lower planar portion has a lesser degree of convergence than the upper planar portion 22b.

The upper edges of each of the side walls 22 are parallel and spaced from each other to be substantially equidistant to each side of the central longitudinal axis of the aperture 14. A support bracket 28 is mounted between the upstanding lip 18 of the base panel 16 and the upper planar portion 22b to provide support for the upper planar portion of each side wall 22.

The brackets 28 also support between themselves a second cowl 30 which has a substantially inverted V-shaped configuration and which is positioned to overlie the aperture 14. The width of the second cowl 30 is such that the side edges 32 of the cowl 30 extend beyond the upstanding lip_u of the base 16. In addition, the second cowl is supported by the bracket 28 such that it's side edges 32 are spaced upwardly from the upper edge of the lip 18 of the base 16.

The mounting of the lower flange 24 of each side wall 22 to the base 16 is provided with one or more drains 34 at the junction therebetween to provide for the drainage of any water that may collect in the space between the side wall 22 and the base°16. The operation of the ventilator is such that because of the spaced relation between the second cowl 30 and the upstanding lip 18 of the base 16, there is a free flow of air upwardly through the aperture past the second cowl 13 and through the space defined between the upper edges 26 of the side walls 22. Since the second cowl 30 is not located such that its side edges 32 are located below the upper edge of the lip 18 there will is no blockage of any air flow from the aperture 14 as a result of the entrapment of any hot air beneath the second cowl 30 and the upstanding lips 18.

The inclination of each of the side walls 22 is such that air flow induced over the ventilator as a result of wind is substantially non turbulent. The substantially inclined planar nature of the side walls 22 ensure that any wind incident on the side wall will be deflected upwardly over the space between the upper edges 26 of the side walls in a substantially non turbulent manner. The effect of such deflection results in an increase in air speed over the space formed between the upper edges 26 of the side walls 22 and a resultant decrease in pressure in that region which serves to enhance the flow of air through the aperture 14, in addition a region of low pressure will be generated on the downwind side of the ventilator, which will result in a further extraction of air from within the roof space and through the ventilator. Furthermore, the variation in inclination of the upper planar portion with respect to the lower planar portion 22 serves to improve the air flow across the base formed between the upper edges of the side walls 22 and create a greater degree of "lift" in the region of the space between the upper edges 26 of the side walls 22 and thus aids in increasing the air flow through the aperture 14. The ventilator according to the embodiment is a static ventilator which is able to facilitate the free flow of air through it under both static air conditions and in the event of wind. Furthermore, in the event of the wind being incident upon the ventilator, the degree of air flow is enhanced by the configuration of the side walls 22. Furthermore, the ventilator extends over an extended elongate aperture provided in a roof to facilitate a high degree of ventilation from an airspace underneath a roof.

The second embodiment as shown at Figure 3 is of an identical form to the ventilator of the first embodiment, with the exception of the configuration of the second cowl. The ventilator of the second embodiment has a second cowl with upper and lower faces of substantially similar configuration in opposed relation to each other 130. In the second embodiment the second cowl has a diamond shaped cross-section but it should be appreciated that the cross sectional shape of the second cowl could be formed in any one of a number of shapes, the form of the cross sections being such that the flow of air through the ventilator is enhanced.

The third embodiment as shown at Figure 4 comprises a ventilator of similar form to that of the first and second embodiments with the exception that it is formed from a single roll-formed metal section which defines the first cowl 220 and the second cowl 230 and which can be applied directly to a roof 212 to surround an aperture 214 formed in the ridge of_othe roof. The second embodiment differs principally from the first and second embodiments by the absence of a base panel. In the case of the third embodiment the lower flange 224 provided on each of the side walls 222 is fixed directly to the adjacent roof panel 212a and 212b. In addition the second cowl 230 is supported from the first cowl 220 by a web element 240 which extends between the upper edge 226 of each side wall 222 and the outer edge 232 of the second cowl 230. The web is formed with a plurality of apertures 242 along its length to provide for air flow from the ventilator. Where the ventilator is applied to a corrugated roof panel, drainage of any"water from within the space defined by the ventilator 210 is facilitated between the lower flange 224 and the corrugations of the roof panel.

The fourth embodiment shown at Figure 5 is of a similar form to that of Figure 1 however in the case of the embodiment as shown where it is to be applied over a flat roof. The ventilator incorporates a base 316 which is to be applied over the roof to surround an aperture 314 formed therein. The "opening provided in the base 316 is defined by an upwardly extending lip 318. The first cowl 320 comprises a pair of opposed side walls 320 which are interconnected at their ends by end panels (not shown) the side walls 320 are located such that their upper edges 326 are spaced equidistant to each side of the central axis of the opening 314 and are spaced outwardly from the upstanding lip 318. The side walls 322 are formed with a lower planar section 322a and an upper planar section 322b which are upwardly convergent and where the degree of convergence of the lower portion is less that the degree of convergence of the upper portion. The upper planar portion 322b is supported from the base 316 by an upstanding bracket 328. In addition the brackets 328 support between themselves the second cowl 330. In the case of the third embodiment the second cowl 330 is formed of a light transmitting material which may be translucent or transparent and which is supported at its edges by a suitable frame 350. If desired the light transmissive material forming the second panel 313 may be fusible such that it will melt on a fire being present within the space below the ventilator to facilitate the venting of smoke being generated within the building. In the case of each of the embodiments, a ventilator is provided which is easily manufactured and has little or no moving parts or mechanical controls which results in a ventilator which is not prone to wear and is thus of improved reliability. Further the ventilators of the embodiments are weatherproof and may be readily applied over a relatively large aperture provided in a roof where the venting of air from the space defined by the roof will take place under both static and non static air-conditions and whereby in the event of wind being incident upon the ventilator the flow of air from the ventilator will be enhanced as a result of the deflection of the air flow over the side walls.

In the case of the first, second and fourth embodiments the base may accommodate a flow control device (not shown) to facilitate the control of air through the aperture 14.

It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiments^"described above.

Claims

THE CLAIMS defining the invention are as follows:-

1. A ventilator which is adapted to be received over an elongate slot shape aperture provided in a roof comprising a first cowl which is to be located to each side of the aperture and to be coextensive therewith said first cowl having a first side wall located to one side of the aperture, and a second wall located to the other side of the aperture and an end wall at each end interconnecting each side wall, the upper edges of the side walls being spaced from each other above the aperture, said first and second side wall being substantially planar and convergent towards each other, where the degree of inclination of the side wall is such that air flowing over the side walls is deflected in a substantially non turbulent manner whereby the air flow over the air space between the upper edges is caused to move at an increased velocity to produce a greater air flow from the vented space said ventilator further comprising a second cowl located between said side walls and beneath the upper edge of said side walls, said cowl overlying the aperture and extending between the end walls of the first cowl, the side edges of the second cowl being spaced above the aperture and being spaced inwardly from the side walls.

2. A ventilatβr as claimed at claim 1 wherein each side wall comprises a lower and upper planar portion whereby the lower portion has a lesser degree of convergence than the upper portion.

3. A ventilator as claimed at claim 1 or 2 wherein the ventilator incorporates a base which overlies the roof to either side of the aperture and is formed with a central opening conforming substantially to the configuration and dimensions of the aperture wherein said first cowl is fixed at its lower edge to the base.

4. A ventilator as claimed at claim 3 wherein the edges of the opening are defined by an upstanding portion which surrounds the aoerture.

5. A ventilator as claimed at claims 3 or 4 wherein the second cowl is supported from said base by an upstanding bracket to each side of the opening.

6. A ventilator as claimed at claim 5 wherein the bracket can support the upper edge of the adjacent side wall.

7. A ventilator as claimed at any one of claims 1 to 6 wherein the ventilator is to be mounted over an aperture provided in the ridge of a pitched roof.

8. A ventilator as claimed at any one of claims 1 to 7 wherein a flow control means is provided in association with the opening.

9. A ventilator as claimed at anyone of claims 1 or 2 or claims 7 or 8 as defined at claims 1 or 2 wherein the first and second cowl are formed by a metal section whereby the upper edge of each side wall is interconnected with the adjacent side edge of the second cowl by a web having apertures formed therein.

10. A ventilator as claimed at any one of claims 1-9 wherein said second cowl has an upper and lower face of substantially similar configuration in opposed relation to each other.

11. A ventilator as claimed at claim 10 wherein said second cowl has a substantially diamond shaped cross- section.

12. A ventilator as claimed at any one of claims 1 to 11 wherein said second cowl is formed at least partially from a light transmissive material.

13. A ventilator as claimed at claim 12 wherein the second cowl is formed oof a fusible material.

14. A ventilator substantially as herein described.