EP3367013A1

EP3367013A1 - Air vent

Info

Publication number: EP3367013A1
Application number: EP17157506.1A
Authority: EP
Inventors: Erik BJØRN
Original assignee: Airmaster AS
Current assignee: Airmaster AS
Priority date: 2017-02-22
Filing date: 2017-02-22
Publication date: 2018-08-29

Abstract

The present invention provides a rain-resistant vent. The vent comprises a support frame having an inner perimeter; a set of blades arranged in an array, a first end of each blade being attached to a corresponding first part of the frame, a second end of each blade being attached to a corresponding second part of the frame, a first substantially flat portion forming an initial part of a cross-section of each blade, and the first substantially flat portion is followed by a ridge or valley portion, and at the first end of each blade the first substantially flat portion is at least partly separated from the inner perimeter by an opening allowing water to drain from the first substantially flat portion onto the inner perimeter.

Description

Field of the invention

The present invention relates to air vents.

Background of the invention

Passive air vents are a common way to replace stale air with fresh air. Many state-of-the-art air vents are able to provide a high flow with relatively low noise while providing cover against for instance rain and birds, but have disadvantages.
For instance, louvre-type vents are simple and provide some protection against rain, but they tend to be noisy, and they not particularly rainproof by any standard.

Summary of the invention

In a first aspect, the invention provides a vent comprising:

a support frame having an inner perimeter,
a set of blades arranged in an array, a first end of each blade being attached to a corresponding first part of the frame, a second end of each blade being attached to a corresponding second part of the frame, a first substantially flat portion forming an initial part of a cross-section of each blade, and the first substantially flat portion is followed by a ridge or valley portion, and at the first end of each blade the first substantially flat portion is at least partly separated from the inner perimeter by an opening allowing water to drain from the first substantially flat portion onto the inner perimeter.

A well-known vent illustrated schematically in Fig. 1 comprises blades 103a, 103b, 103c attached to a frame 101. The vent also has a cover flange 102 for fitting the vent against a surface, such as a wall. The blades are flat and arranged at an angle. This provides some protection against rain, which is illustrated as element 121, but there is a significant amount of splashing when rain hits the blades, causing drops to get through the vent, as illustrated by drops 122. Furthermore, the angling of the blades causes air to be redirected, resulting in an uneven pressure profile across the vent going from the top of the vent to the bottom of the vent in Fig. 1.
Fig. 8 illustrates a cross-section of a vent similar to the one in Fig. 1, although the vent 800 in Fig. 8 has blades that allow more rain to enter through the vent. Blades 803a, 803b, and 803c are separated so much that rain can pass between the blades relatively easily, especially in the presence of gusts.
Embodiments of the present invention differ from these known vents at least by comprising blades that are not flat, but have a flat portion followed by a ridge or valley portion. Vents in accordance with embodiments of the present invention create significantly less noise, they may provide a significantly lower pressure drop, and they provide much better rain protection compared to the vents in Figs. 1 and 8.
Fig. 7 illustrates another known vent 700, specifically designed to prevent rain from entering. Blades 703a, 703b, 703c are arranged in an array. The blades are configured with various appendages 751, 752, 753 for catching rain and mist. Due to appendages 751 and 753, the blades at the entry and exit of the vent experience vortices. The specific design also results in a significant pressure drop across the vent, which is not desirable. The large angle of the blades relative to causes air 741, 742 to be redirected, contributing to the significant pressure drop. Embodiments of the present invention differ from the vent in Fig. 7 at least in that the initial portion of the blades are substantially flat, i.e. without crooked appendages.
Not visible in Figs. 1, 7 and 8 is the lack of an opening between the blades and the respective frames, which prevents water to drain to and along the inner perimeter.
Preferably, there is an opening at least 0.5 mm wide from the blade to the inner perimeter, such as at least 1 mm wide, such at least 1.5 mm wide, such as at least 2 mm wide. A larger distance allows a larger flow of water to drain from the blades onto the inner perimeters. However, if the distance is too large, rain will be able to travel along the inner perimeter, through the vent, at higher wind speeds.
The ridge or valley portion helps capture rain. In fact, a ridge is preferred, as this provides a surprisingly effective protection against rain. The flatness of the initial part of the cross-section prevents creation of vortices, as opposed to the vent illustrated in Fig. 7. More importantly, however, the first substantially flat portion allows rain to run along the blade, towards the inner perimeter, and through the openings as described above.
In some embodiments, the first substantially flat portion of two adjacent blades are substantially parallel (such as parallel). This provides a smoother air flow through the vent.
In some embodiments, the ridge or valley portion of the cross-section is followed by a second substantially flat portion forming a final part of the cross-section. Such a second substantially flat portion can be used to direct the air as desired, but more importantly, it can also assist in the draining away of water, just like the first substantially flat portion forming the initial part of the blade. In some embodiments, the second substantially flat portion of two adjacent blades are substantially parallel.
The vent frame can have arbitrary shapes, such as circular or rectangular. This is a matter of design and could be determined by the specific hole in which the vent is should fit.
When air impinges on a front side of a conventional vent along a surface-normal of the front side, air is redirected because the inlets formed by the blades in conventional vents are angled, as exemplified by the conventional vent shown in Fig. 1. The blades are angled to prevent rain from passing through the vent.
In some embodiments of the present invention, the first substantially flat portions of two adjacent blades in the vent form an inlet having an inlet direction that is substantially parallel to a surface normal of a front side of the vent, such as parallel to the surface normal. In some embodiments, the inlet direction deviates from the surface normal by at most 10 degrees.
The vents in Fig. 1 and Fig. 7 have inlets directions that are angled away from the surface normal direction by about 45 degrees, and the vent in Fig. 8 has inlet directions of approximately 34 degrees. Such large inlet angles seem to be accepted, even a norm. However, the inventor of the present invention found that surface-normal inlets can be used without compromising the vent's ability to drain away rain, at large volumes, especially when the surface-normal inlets are combined with the other features of the present invention.
In some embodiments of the present invention, the second substantially flat portions, if present, of two adjacent blades form an outlet having an outlet direction that is substantially parallel to the surface normal, such as parallel to surface normal. In some embodiments, the outlet direction deviates from the surface-normal axis by at most 10 degrees.
In some embodiments, a height, d_o, of a straight through-going vent opening between two adjacent blades is at most 20 % of a height, d_h , of one of the two adjacent blades. This reduces air resistance and yet allows for an effective protection against rain. Ultimately, however, it does allow rain to travel directly through the vent, which is not desirable, but high wind speed are necessary for that to happen. In some embodiments, the height, d_o, of the through-going opening is at most 10 % of the height, d_h . This more effectively prevents rain from entering through the vent directly.
In some embodiments, independent of whether there is a straight through-going opening between the blades or blade elements, or not, the depth of the blades or blade elements , d_l , (i.e. the "length" in the blade or blade element in the air flow direction, which is also the length of the cross-section of the blade or blade element, as illustrated in the drawings) is preferably between 20 mm and 150 mm, such as between 50 mm and 150 mm, such as between 50 mm and 120 mm, such as between 50 mm and 100 mm.
In some embodiments, a height of the blades or blade elements, d_h , is between 5 mm and 50 mm, such as between 5 mm and 30 mm, such as between 10 mm and 30 mm.
In some embodiments, there is no straight through-going opening between a pair of adjacent blades. This completely prevents rain from travelling straight through the pair of adjacent blades. Rain will encounter the blade surfaces and be slowed down. This slowdown provides for a very efficient draining, as the slower speed of the rain through the vent means that the rain has more time for draining away towards the inner perimeter.
In some embodiments, the blade ridge part is smooth, i.e. has no appendages or edges that cause vortices, eddies, turbulence, or similar disturbances. This gives the smoothest and least noisy performance. In other embodiments, the blades have edges. For instance, the ridge may have an edge, for instance at the top of the ridge.
In some embodiments, each blade is straight in a direction between the blade's first end and the blade's second end. This has some advantages, for instance ease of manufacturing. However, embodiments of the present invention should, in use, be arranged so that the blades are not horizontal, to make sure rain quickly drains towards the perimeter of the frame. This provides a fast and efficient draining.
In some embodiments, this is improved by providing blades that comprise a first blade element extending from the first end of the blade and a second blade element extending from the second end of the blade, the first and second blade elements being joined to one another at a joint position between the first and the second end of the blade, the first blade element being joined to the second blade element at an angle. Preferably, the first blade element is a mirror version of the second blade element, or at least substantially a mirror version. In other words, the blade is symmetrical around the joint point. Considered from the front, such blades are symmetric. This is aesthetically advantageous.
Preferably, a smallest angle, α, between the blade elements of a blade is between 20 and 160 degrees, such as between 90 and 150 degrees, such as between 100 and 130 degrees.
In some embodiments, the vent comprises a drain configured to carry water away from a bottom portion of the vent. In some embodiments, the drain comprises a duct having an inlet at said bottom portion of the vent to receive water from the inner perimeter of the vent and having an outlet configured to drain water out of the duct. The duct encloses the water, which shields the draining water from winds. This prevents water from being carried into the vent under higher wind speeds. Another form of drain may be used, such as an open conduit. However, the open conduit does not shield the water, and therefore water may be carried into the vent under high wind speeds.
A second aspect of the invention provides a method for mounting a vent in accordance with the first aspect of the invention. The method comprises: arranging the vent in such a way that at least two of the blades or blade elements in the array of blades are slanted from horizontal by at least 10 degrees. If the vent is formed from blade elements, preferably all blade elements are slanted from horizontal by at least 10 degrees. If the blades in the vent are straight blades, the aesthetics might be negatively affected.

Brief description of the drawings

Figure 1 illustrates a conventional louvre vent.
Figure 2 illustrates a perspective vent in accordance with an embodiment of the invention.
Figure 3 illustrates a front view of the vent shown in Figure 2.
Figure 4 is a detailed view of ends of the blades in the vent shown in Figure 2.
Figure 5a illustrates a cross-section of blades in the vent shown in Figure 2.
Figure 5b is a detail view of a cross-section of blades in an alternative embodiment of the invention.
Figure 5c illustrates a cross-section of blades in another alternative embodiment of the invention.
Figure 5d illustrates a cross-section of blades in yet another alternative embodiment of the invention.
Figure 6 illustrate flow of rain capture by the vent shown in Figure 2.
Figure 7 illustrates a prior-art vent that can capture rain.
Figure 8 illustrates another conventional louvre vent.
Figure 9 illustrates pressure drop for various types of vents, including known vents and vents in accordance with embodiments of the present invention.

Detailed description of selected embodiments

In the following, the invention is described in terms of specific embodiments and with reference to the accompanying drawings.
Fig. 2 illustrates a vent 200 in accordance with an embodiment of the invention. It comprises a frame 201 having an inner perimeter 202. Blades 203a, 203b, 203c, 204a, 204b, 204c are attached to the frame 201 at respective attachment points. In this view, it can be seen that blades 204a, 204b, 204c are attached at respective points 207a, 207b, and 207c. The vent furthermore has a cover flange 210 for engaging with a wall or similar surface to fit the vent relatively tightly to the surface. The vent furthermore has a drain 212 for draining away water that runs to the bottom of the vent.
Each blade in the vent in this embodiment consists of two elements. One blade consists of blade element 203a that meets blade element 204a at the horizontal midpoint of the vent. Similarly, the blade below it consists of blade elements 203b and 204b, and the blade below that consists of blade elements 203c and 204c. The blade elements of each blade are arranged symmetrically around the horizontal midpoint of the vent. Blade element 203a is angled downwards in a direction towards its attachment point at the frame. Similarly, corresponding blade element 204a is angled downwards in a direction towards its (visible) attachment point 207a. The same applies for blade element 203b and corresponding blade element 204b, and for blade element 203c and corresponding blade element 204c. The angling of the blade elements means that water impinging on the blades will run down the blades by means of gravity.
Fig. 3 is a front view of the vent. The figure specifically illustrates a smallest angle, α, between corresponding blade elements 203a and 204a. The angle in this example is 120 degrees. Each blade element is angled 30 degrees from horizontal.
The symmetrical construction of the vent described above provides an aesthetically non-provoking look. Asymmetric vents sometimes annoy some observers. However, a lack of symmetry is not detrimental to the effect of the vent, which will still perform well even if the blade elements do not form approximately the same angle with respect to horizontal.
The vent works well within a large range of values of the angle α. An angle as small as 10 degrees from horizontal for the blade elements still provides a very large draining effect. However, below that, the draining effect is substantially reduced. On the other hand, blades that are closer to vertical, i.e. where the angle between the blade elements is e.g. 20 degrees (i.e. α=20 degrees) will also be effective, but the aesthetic aspect suffers somewhat in this configuration.
Fig. 5a illustrates the various parts of the blade cross-sections that characterize this specific embodiment of the invention. Fig. 5a is a cross-section down through the middle of the vent in Fig. 2. Blade portion 511 is the first substantially flat portion that forms the initial part of the cross-section of each blade. This portion is followed by a ridge portion 512. This particular embodiment comprises the optional feature of the ridge portion of the cross-section being followed by a second substantially flat portion forming a final part of the cross-section. (If the second substantially flat portion is not present, the ridge portion forms the final part of the cross-section.) Note that since portion 512 is a ridge, the will be an upward gradient between the first substantially flat portion and the ridge portion, and a downward gradient from the ridge potion to the second substantially flat portion.
Fig. 5a illustrates an important feature of the present embodiment, namely that rain is not able to pass through the vent without getting into contact with the vent. Arrow 560 illustrates the closest water moving in a straight line would get to travelling directly through the vent. However, because of the shape of the blades and distance between them, rain 521 has no chance but to hit a surface of the blades, where it will break into smaller drops. Fig. 5a illustrates drops 524 that have run down the ridge toward the rainy side. As will be described below, these drops will also move "into" the page. This is because the blade element that supports them is slanted, as for instance Fig. 3 shows. The drops run to the inner perimeter, through the openings between the flat parts and the inner perimeter, and downwards along the inner perimeter. This will described in more detail in relation to Fig. 6 later in this specification.
Fig. 4 illustrates the vent with a cutaway to better show an essential feature of the invention, namely the openings between the flat portions of the blades and the inner perimeter of the frame. These openings allow the water to run from the flat portions onto the inner perimeter 202. Conventionally, louvres in vents are arranged to be horizontal between the frame edges, also shown in Fig. 1, and there are no openings between the blades and the frame of the vent. Rain will therefore simply fall off the blades on the rainy side of the vent, typically in a drip-wise fashion.
Fig. 4 illustrates edges of blade elements 404m and 404n attached to the frame 201. The openings that separate the flat portions from the frame are visible in the drawings (also for blade elements below blade elements 404m and 404n). The right-hand side of the drawing shows blade elements 404m and 404n in more detail, including their respective attachment points 407m and 407n. Focusing first on blade 404n, arrow 409n illustrates an opening between the ridge portion of the blade and the frame 201. Little water actually drains away this far up the ridge, but the opening allows any water there to do so. Note that this opening is optional.
Focusing next on blade 404m, the arrow 410m illustrates the essential feature that at an end of the blade, the first substantially flat portion is at least partly separated from the inner perimeter by an opening allowing water to drain from the first substantially flat portion onto the inner perimeter. The circle at the end of the arrow 410m shows the first substantially flat portion as well as the opening.
These openings are also visible in the front view in Fig. 3, where it can be seen that these openings in the present case actually form a ring-shaped opening through the vent along the inner perimeter, interrupted by the attachment of the blades to the frame.
Fig. 5a shows droplets 522 that illustrate a droplets and mist of water created at the impact of rain 521. These droplets/mist tend to move into the vent, away from the rainy side, due to the air movement. It turns out that essentially none of these droplets/mist gets through the vent, even at a rainfall any one is likely to encounter. Instead, it gets into contact with the blades and run along the bottom side of the blades towards the inner perimeter, as illustrated by drop 523. Finally, a relatively small amount of water fall onto the blade below, as illustrated by drop 525. Again, by virtue of the slanted configuration of the blade, this drop will travel towards the inner perimeter, through the opening, and downwards.
Fig. 5a also illustrates another feature of the present embodiment. At the bottom of the vent, there is a drain 212 that receives water from the inner perimeter of the frame through openings 436. From there, the water drains into a duct and to an outlet 437 pointing downwards. This drain provides an important effect: Although the vent performs well without the duct drain, water may be able to travel through the vent, forced by wind. The duct has the advantage that it provides wind cover for water at the bottom of the vent, thereby preventing the water from being blown inwards.
Fig. 5b illustrates blades 504a, 504b, 504c in an embodiment where the blades are arranged in such a way that there is a straight through-going opening between pairs of adjacent blades. Although the drawing shall not be construed as being drawn to scale, the scale in Fig. 5b does indicate that even with straight through-going openings, rain in unlikely to get through the vent in a straight line. Most likely, the interaction with the blade will be similar to that in Fig. 5a.
Fig. 5b illustrates a height, d_o, of a straight through-going vent opening between two adjacent blades. A blade height, d_h , of one of the blades is also illustrated. Preferably, the height of the straight through-going vent opening is at most 20 % of the height of the blade. However, the depth of the blade, d_l , (i.e. its "length" in the air flow direction, which is also the length of the cross-section) influences what opening height can be accepted. The longer the blades, relative to their height, the higher the opening between blades can be without rain being able to get through the vent and leaving the vent inwards. Almost any rain will be slowed by the blades and drain off towards the inner perimeter and downwards.
Fig. 5c illustrates another embodiment 591 of the invention. Here, the ridge is not rounded as in Fig. 5a, but instead has an edge. This embodiment does provide good cover against rain, but the edge at the ridge creates more acoustic noise than the rounded ridge shown in Fig. 5a. The embodiment does not have a drain similar to that in Fig. 5a, but this is straightforward to add.
Fig. 5d illustrates yet another embodiment 592 of the vent. Here the blades have a valley rather than a ridge between the first and second substantially flat portions. Intuition might tell some that this vent is more efficient in draining rain. This is actually not the case, by any means. An important reason for the lower efficiency is that water is collected in the valley portion. Rain that enters then splashes into the rain collected in the valley portion, and the geometry allows drops from such splashes to travel further into the vent, a process that is enhanced by any wind that might be present. Furthermore, the effective depth of the valley portion is reduced by water present in the valley.
In all the embodiments in Figs. 5a to 5d, the flat portions form straight inlets and outlets. On average, wind tends to move horizontally. When arranged vertically with the two sides of the vent arranged to be vertical, straight inlets and outlets results in the least amount of noise. Inlets in the prior art, for instance those vents shown in Figs. 1, 7 and 8, have angled inlets. Presumably, the angled inlets are considered necessary to provide good cover against rain. It turns out that this is not the case, as the inventor of the present invention has found.
Fig. 6 illustrates what takes place when the vent shown in Fig. 2 is exposed to winds and rain, as also illustrated in Fig. 5a. The reference numbers differ slightly where necessary. Wind 620 carrying rain 621 reaches the vent. When rain comes into contact with the blades, the drops are slowed down and tend to gather on the first substantially flat portion 511, as illustrated by drops 622. From there, the drops move towards the perimeter, as illustrated by line 631, because the blades are slanted. Due to the openings between the first substantially flat parts and the inner perimeter (illustrated in detail in Fig. 4), the drops run onto the inner perimeter and downwards, as illustrated by line 632. As described in relation to Fig. 5a, very little water gets past the ridge 512, as illustrated by the few and small drops 623. Furthermore, those drops are effectively stopped or at least slowed down, and will be carried to the inner perimeter via the second substantially flat portion 513. As described above, the major part of those drops attach to the underside of the blade above the drops and runs towards the perimeter.
Finally, at the bottom of the vent, the water reaches the drain 212 through opening 436. The drain 212 acts as a duct, leading water towards the outlet 437 of the drain, as illustrated by line 633.
Fig. 8 illustrates the cross-section of a conventional vent 800 similar to the one in Fig. 1. The vent in Fig. 8 is more open, though, in the sense that the blades are less angled relative, and they are separated more. Not only is this vent not very rain-resistant, it also provides a relatively high air resistance compared to embodiments of the present invention described above.
Fig. 9 is a comparison of the pressure drops at different air speeds across prior-art vent 800 ("1" in the legend), prior-art vent 700 ("4" in the legend), and embodiments 200 and 591 of the present invention ("2" and "3", respectively, in the legend). It is clear that the pressure drop across the prior-art vents is substantially higher than across the embodiments of the present invention, actually by a factor of around 2. For prior-art vent 700, which is highly rain resistant, the factor is around 3. This is in large part due to the straight inlets of the embodiments 200 and 591. This is a further advantage of these embodiments, on top of their ability to prevent rain from entering.

Claims

A vent (200), comprising:
- a support frame (101) having an inner perimeter (202),

- a set of blades (203a,203b,203c,204a,204b,204c) arranged in an array, a first end (206a, 206b, 206c) of each blade being attached to a corresponding first part of the frame, a second end (207a, 207b, 207c) of each blade being attached to a corresponding second part of the frame, a first substantially flat portion (511) forming an initial part of a cross-section of each blade, and the first substantially flat portion (511) is followed by a ridge or valley portion (512), and at the first end of each blade the first substantially flat portion (511) is at least partly separated from the inner perimeter by an opening (410m) allowing water to drain from the first substantially flat portion (511) onto the inner perimeter (202).
A vent in accordance with claim 1, wherein the first substantially flat portion (511) of two adjacent blades (203a, 203b, 204a, 204b) are substantially parallel.
A vent in accordance with claim 1 or 2, wherein the ridge or valley portion (512) is followed by a second substantially flat portion (513) forming a final part of the cross-section.
A vent in accordance with claim 3, wherein the second substantially flat portion (513) of two adjacent blades are substantially parallel.
A vent in accordance with claim 2, wherein the first substantially flat portions of two adjacent blades form an inlet having an inlet direction that is substantially parallel to a surface normal of a front side of the vent.
A vent in accordance with claim 4 or 5, wherein the second substantially flat portions of two adjacent blades form an outlet having an outlet direction that is substantially parallel to a surface normal of a front side of the vent.
A vent in accordance with one of the preceding claims, wherein a height of a straight through-going vent opening between two adjacent blades is at most 20 % of a height of one of the two adjacent blades.
A vent in accordance with any of the preceding claims, wherein the first substantially flat portion is followed by a ridge portion.
A vent in accordance with one of claims 1-6, wherein between a pair of adjacent blades there is no straight through-going opening.
A vent in accordance with one of the preceding claims, wherein each blade is straight in a direction between the blade's first end and the blade's second end.
A vent in accordance with one of claims 1-9, wherein each blade comprises a first blade element extending from the first end of the blade and a second blade element extending from the second end of the blade, the first and second blade elements being joined to one another at a joint position between the first and the second end of the blade, the first blade element being joined to the second blade element at an angle.
A vent in accordance with claim 11, wherein each blade is symmetrical around the joint point.
A vent in accordance with one of the preceding claims, further comprising a drain configured to carry water away from a bottom portion of the vent.
A vent in accordance with claim 13, wherein the drain comprises a duct having an inlet at said bottom portion to receive water from the bottom portion and having an outlet end configured to drain water out of the duct.
A method for mounting a vent in accordance with one of claims 1-14 in a duct, the method comprising: arranging the vent in such a way that at least two of the blades or blade elements in the array of blades are slanted from horizontal by at least 10 degrees.