The present invention relates to a ventilation arrangement for ventilating a building interior.

The provision of adequate ventilation is an important consideration in building design. The combination of heat gains generated within buildings by occupants and electrical equipment and solar heat gain can cause a significant build up of heat and, therefore overheating.

Air conditioning or other mechanical ventilation systems can be used to provide ventilation to buildings to address these difficulties. However, such systems consume electricity and can, therefore, be relatively expensive to operate.

One prior arrangement is to provide a duct extending from just above roof level into a building, with the upper end of the duct connecting to outwardly facing openings extending around the duct. During use air can enter the windward side of the duct through respective openings, with stale air exiting from the building through respective openings on the leeward side of the duct.

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In such a configuration, the duct is divided by radial dividers, which could for instance divide the duct into four quadrants, with the quadrant nearest the windward side receiving the most air to ventilate the building, whilst the majority of air extracted from the building exits through the opposite quadrant on the leeward side of the arrangement. Such arrangements have operated successfully in providing ventilation with little or no power input. However, problems can be encountered in extreme weather with such arrangements, for example with very heavy rain and particularly snow, leading to ingress of precipitation into the apparatus. According to . the present invention there is provided a ventilation arrangement for ventilating a building interior, the ventilation arrangement comprising: an air duct which extends in use from roof level into an interior of the building to be ventilated to convey air between the exterior and interior of the building; ventilation openings which extend around an upper part of the air duct to direct moving air caused by wind movement into or out of the air duct; the ventilation openings having a louvre configuration defining a plurality of discrete openings, one above each other; the louvre configuration being configured such that each opening is defined by a passage extending from the exterior into the ventilation arrangement; the passage extending generally upwardly inwards to avoid the ingression of liquids and other precipitation; with an upper surface of the passage being concavely curved to urge downwardly air entering through the passage.

The passage may extend upwardly, and at an inclination of between 20 and 40°.

The upper surface of an inner part of the passage may be concavely curved.

The upper syrface of the inner part of the passage may extend inwardly for a distance of between 35 and 60mm, and more particularly between 40 and 50mm.

The curved upper surface of the inner part of the passage may have a radius of between 55 and 65mm.

The upper surface of an outer part of the passage may be concavely curved. The upper surface of the outer part of the passage may extend inwardly for a distance of between 35 and 60mm, and more, particularly between 40 and 50mm. The curved upper surface of the outer part of the passage may have a radius of between 30 and 50mm, and more particularly between 35 and 45mm.

The outermost part of the upper surface of the outer part of the passage may extend substantially vertically.

The lower surface of an inner part of the passage may be concavely curved to accelerate air entering through the passage. The lower surface of the inner part of the passage may have a radius of between 35 and 45m.

The mouth of the ventilation opening may be between 30 and 70mm wide, and more particularly between 40 and 60mm wide, and especially between 45 and 55mm wide.

The louvre configuration may be active so as to selectively partially or wholly close the passages. The louvre configuration may comprise a plurality of movable first components and static second components, with the first components being simultaneously movable with each other, with each passage being defined between a respective pair of first components and a respective pair of second components.

The first components may be moveable over a distance of 40 and 70mm, and more particularly 50 and 60mm, between fully open and fully close positions. The first components may each extend vertically for between 40 and 70mm, and more particularly 50 and 60mm.

The second components may define an outer part of the passage when open, with the first components defining an inner part of the passage. The first components may have concave upper and lower surfaces.

The underside of the second components, at least at an outer part thereof, may be concave.

The degree of concavity of the second components may be greater than that of the first components.

A substantially vertical downwardly facing slot may be provided in the first components towards the external side thereof, which slot is slidingly locatable over a formation on a respective second component, such that when the slot is fully located over the formation the passage is fully open, and as the first components are moved relative to the second components the slot is moved off the formation causing closing of the respective passage.

The slots may each extend vertically for between 40 and 70mm, and more particularly 50 and 60mm.

The formation on the second components may be in the form of an upwardly extending flange provided on the inner edge of the second component.

The ventilation arrangement may be substantially polygonal in plan view, with first and second components for each side of the polygon. The ventilation arrangement may be substantially rectangular in plan view. The movable first components may be interconnected so as to be simultaneously movable, and link members may interconnect the first components. A respective one of a plurality of link members may interconnect respective ends of the first components.

The link members may be interconnected, and may all be connected to an actuator member.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:-

Fig. 1 is a diagrammatic perspective view of part of a ventilation arrangement according to the invention; Fig. 2 is a diagrammatic cross sectional view of part of the arrangement of Fig. 1 in an open condition;

Fig. 3 is a similar view to Fig. 2 but in a closed condition; and Fig. 4 is a diagrammatic cross sectional view of part of the interior of the part of the ventilation arrangement of Fig. 1.

Fig. 1 shows the exterior of a housing 10 of a ventilation arrangement which housing 10 is mountable on the roof of a building. Within the housing 10 is a duct which extends downwardly to transport air to and from the interior of the building.

The housing 10 is substantially square in plan view, with a louvre arrangement 12 on each side of the arrangement 10. The louvre arrangement 12 is intended to receive air on a windward side of the housing 10 to enter the duct 18, and to expel air received through the duct 18 on the opposite leeward side. This invention relates to the louvre arrangement 12 which will now be considered in more detail. The size of the arrangement 12 can be determined by a particular situation, but likely dimensional ranges are included below. Each louvre arrangement 12 defines a plurality of passages 14 on the respective side of the housing 10, which passages 14 are selectively partially or wholly closable. Each louvre arrangement 12 comprises a plurality of spaced static second louvre components 16 on an external side of the louvre arrangement 12, and a plurality of spaced movable first louvre components 18 on an interior side thereof.

The second louvre components have on an internal side an upstanding vertical flange 20 . extending for between 40 and 70mm. Extending downwardly and outwardly for a horizontal distance of between 35 and 60mm from the flange 20 is a web 22, which interconnects to a further downwardly extending vertical flange 24, which flange 24 extends for between 25 and 50mm. The inner face of the flange 24 and an outer part of the web 22 is profiled to define a concave surface 26 with a radius of between 30 and 50mm, to urge air passing thereby to turn inwardly and downwardly.

The first movable louvre components 18 are in the form of mouldings with concave upper and lower faces 28, 30, with a slightly greater degree of concavity on the upper faces 28, and respective radii in the ranges 35 to 45mm and 55 to 65mm. A downwardly facing slot 32 is provided adjacent the external edge of the first components 18, and is of a size to slidingly fit over the flange 20 of the second components. The first moveable components 18 have a height of between 40 and 70mm, and a depth of between 35 and 60mm. The first movable components 18 are interconnected by linkage bars

34 at their respective ends. Fig. 4 shows two such linkage bars 34 attachedo the first components 18, though in Fig. 4 the first and second components 18, 16 have been shown diagrammatically and not with their full profile. The linkage bars 34 are all interconnected by cross bars 36 one of which is shown in Fig. 4, and the cross bars 36 are attached to an actuator member (not shown) for actuation. The actuation may be provided manually, or by an electric motor or an actuator, and automatic operation thereof may be provided.

In use in a fully opened condition as shown in Fig. 2, air as shown by the arrows 38 will enter the passages 14 which have an opening of between 30 and 70mm, substantially parallel to the webs 22 but turn upwardly upon encountering the external faces of the first louvre components 18. The air is then guided inwardly and downwardly by the concave surfaces 26. As the air moves further in it is also directed downwardly by the lower faces 30 on the first louvre components 18, whilst also being accelerated by virtue of the decreasing gap caused by the concave upper faces 28.

The right hand most arrow 38 shows the air entering into the interior of the ventilation arrangement 10 substantially horizontally, as opposed to in the direction of the outer part of the passage defined by the web 22, which would generally be at an upwards inclination of between 20 and 40°.

If it is required to partially or wholly close the passages 14, for instance in the event of inclement weather, the first louvre components 18 can be moved upwardly such that the slot 32 moves off the vertical flange 20, and the components 18 can be moved to a fully closed position as shown in Fig. 3.

There is thus described a ventilation arrangement which provides for an improved passage of air thereinto, with turning of the air downwardly as it enters the arrangement to provide increased efficiency. There is also described a louvre ^' arrangement permitting partial or complete closing as required. Various modifications may be made without departing from the scope of the invention. For instance the louvre arrangements may have different profiles. The movable louvre components may be interconnected and/or movable in a different manner. The movable static louvre components may engage with each other in a different manner.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.