GB2211598A

GB2211598A - Preventing ingress of rain through ventilation louvres

Info

Publication number: GB2211598A
Application number: GB8724383A
Authority: GB
Inventors: Alan Bell
Original assignee: STEELPRESS
Current assignee: STEELPRESS
Priority date: 1987-10-17
Filing date: 1987-10-17
Publication date: 1989-07-05
Anticipated expiration: 2007-10-17
Also published as: GB8724383D0; GB2211598B

Abstract

A louvre blade for use in a louvre ventilation system is of plate construction adapted at one edge B for fitting to a wall or frame while the other, front, edge F comprises a bent lip portion (5), preferably of bullnose having on aperture 10 which promotes recirculation of air entering past the lip. This inhibits the ingress of rain. A hood 11 is located over aperture 10. <IMAGE>

Description

"Louvre Blade" Description The present invention relates to a louvre bLade for use in natural louvre ventilation systems.

Natural louvre ventilation systems are of course well known and comprise an array of parallel louvre blades carried by support means, the blades being inclined from the vertical to shield associated ventilation apertures in the system. The inclined louvre blades which can be of fabricated form or made by an extrusion process, provide a weathering characteristic to the system, that is preclude or mitigate against the passage of rain through the system, while still allowing airflow in either direction through the system. The weathering characteristic can be improved by various changes in the system, such as for example by reducing the spacing pitch of the blades, but by and large these changes have the effect of reducing the effective passage area between adjacent louvre blades and consequently reducing the airflow performance of the ventilation system.

It is an object of the present invention to provide an improved louvre blade enabling the provision of improved weathering in louvre ventilation systems while still allowing the systems to have satisfactory airflow performance. According to the present invention a louvre blade for use in louvre ventilation systems has a bent lip portion at the front end of the blade, and air-recirculation aperture means are provided in said bent lip portion.

Preferably said air-recirculation aperture means comprise an opening in the bent lip portion, and a shield element over said opening. The shield element can be arranged such that air passing through said opening is directed downwardly by the shield element.

Preferably said shield element comprises a bent-out part of the lip portion.

In a preferred embodiment, the bent lip portion is of bullnose form. The opening can be located on a front land of the bullnose Lip with swept back lip parts on either side of said land. The bullnose lip can define a hollow enclosure with an air inlet to the enclosure, said opening of the aperture means defining an air outlet from the enclosure.

Preferably the blade has a substantial planar portion and the plane of said opening is set at an acute angle to said planar portion. The aperture means can comprise a series of spaced openings, eg. of slot form, each with an associated shield element.

The present invention is also a ventilation system using louvre blades in accordance with the invention as defined above.

An embodiment of the present invention will now be by way of example, with reference to the accompanying drawings, wherein: Fig. 1 shows a schematic side view of part of a louvre ventilation system using louvre blades in accordance with the present invention; and Fig. 2 shows a pictorial view of part of a louvre blade of Fig. 1.

Referring to the drawings, a louvre ventilation system comprises a series of louvre blades 1 arranged in vertical array as shown in Fig. 1 and carried by a suitable support structure including for example column 2.

The blades 1 are arranged in parallel and each blade 1 has a major planar portion 3 set at an acute angle a to the vertical so that the blades are downwardly inclined, the blades being spaced apart with a pitch P. Values of P and a are chosen to give desired weathering and airflow performance in the system.

The blades 1 are preferably fabricated by pressing and stamping operations on metal strips eg. steel or aluminium strips, and the front (leading) F and back (trailing) B ends of the blade 1 are shaped to provide bent lip portions. The bent lip at the front end F is shaped to define a hollow enclosure 4, having a front wall 5 and rear converging walls 6, 7, the wall 6 being bent back from the planar portion 3. In particular the lip at end F is of bullnose form. Further, the lip at F is bent to define an air inlet 8 to the enclosure 4.

The ventilation system can cater for an externalinternal airflow per arrow V in Fig. 1 or for an opposite internal-external airflow. For both cases the system must have a suitable weathering property particularly for a slanted direction of rainflow, and the blades 1 include means to improve the weathering property of the system. Thus, the bent lip at F includes aperture means 9 for the creation of a recirculating airflow A. More specifically these aperture means 9 comprise a series of slotted openings 10 (see Fig. 2) defining an air outlet from the enclosure 4, and a shield or hood 11 associated with each opening 10 to direct the airflow A downwardly as shown. The opening 10 is located on a front land 5A (Fig. 2) of the wall 5, front wall portions 5B, 5C at the sides of land 5A being swept backwardly to assist desired airflow patterns.The openings 10 can be stamped out from the blade lip with hood 11 integral with the lip.

It is arranged that with the ventilation system in position the plane of the opening 10 is vertical and therefore forms an acute angle with the blades planar portion 3.

Referring especially to Fig. 1, horizontal airflow impinging on the planar portion 3 of one blade 1 of the ventilation system is deflected upwardly towards the upper adjacent blade as shown by arrow D, while horizontal airflow impinging on the bullnose lip at F of said upper blade is split into two portions by the wall 5, namely a downwardly deflected portion indicated by arrow B and an upwardly directed portion shown by arrow C. There is thus created a back airflow betwe-en adjacent blades 1 resulting in a recirculating airflow passing into the lip enclosure 4 of the upper blade via inlet 8 whence it is discharged as flow A from the openings 10, the flow A blending with the compatible airflow B. The cross airflow patterns between successive blades 1 create a barrier to rainflow between the blades and through the louvre ventilation system, and this gives rise to an improved weathering property in the system.

Modifications are of course possible. For example, the aperture means 9 at the front lip F could take some other form from that shown and the bent lip at end F could be shaped differently.

Claims

1. A louvre. blade for use in louvre ventilation systems includes a bent lip portion at the front end of the blade, air-recirculation aperture means being provided in said bent lip portion.

2. A louvre blade as claimed in claim 1, wherein said air-recirculation aperture means comprise an opening in the bent lip portion, and a shield element over said opening.

3. A louvre blade as claimed in claim 2, wherein the shield element is arranged such that air passing through said opening is directed downwardly by the shield element.

4. A louvre blade as claimed in claim 2, or 3, wherein said shield element comprises a bent-out part of the lip portion.

5. A louvre blade as claimed in anyone of the preceding claims, wherein the bent lip portion is of bullnose form.

6. A louvre blade as claimed in claim 5, wherein the opening is located on a front land of the bullnose lip with swept back lip parts on either side of said land.

7. A louvre blade as claimed in claim 5 or 6, wherein the bullnose lip defines a hollow enclosure with an air inlet to the enclosure, said opening of the aperture means defining an air outlet from the enclosure.

8. A louvre blade as claimed in anyone of the preceding claims, wherein the blade has a substantial planar portion and the plane of said opening is set at an acute angle to said planar portion.

9. A louvre blade as claimed in anyone of claims 2 to 4 wherein the aperture means comprise a'series of spaced openings each with an associated shield element.

10. A louvre blade substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

11. A ventilationsystem including louvre blades as claimed in anyone of the preceding claims.