Field of the Invention

The present invention relates to an Air inlet primarily for an outdoor application for cooling air, which air inlet has an outdoor inlet and an indoor outlet, which air inlet comprises means for preventing water drops passing the inlet, which inlet further comprises means for preventing sand particles in passing the inlet, which inlet comprise a plurality of longitudinal channels for the air to pass. Background for the invention;

US6575826 discloses an air vent for protecting a public potable water system against terrorism and sabotage. The US patent allows the movement of air but will not allow any liquids or solids to pass through the vent even if these liquids or solids are being applied under pressure. This is accomplished by an energy dissipating arrangement of S-shape structural members.

Object of the Invention

It is the object of the pending application to disclose an air inlet for an outdoor instal- lation.

Description of the Invention

The object can be achieved by an air inlet as disclosed in the preamble to the claim 1 if the longitudinal channels are placed vertically, which channels comprises a first open inlet channel, which inlet channel continues into a second channel, which second channel is mostly perpendicular in relation to the first inlet channel, which second channel continues into a third channel, which third channel is mostly perpendicular in relation to the second channel, which third channel continues into the fourth outlet channel. Hereby it can be achieved that the air inlet is able to reject water droplets simply because water droplets have a mass considerably higher than the mass of the air molecules. The air molecules are able to turn the direction of movement but the water droplets contained in the air will hit mostly the wall of the second channel where the air stream at first is forced to change the direction 90 degrees. Most of the water drops continue directly into the wall where the droplets form a splash-out at the wall and gravity forces the water to fall downwards at the flange that has received the droplets. If small amounts of water or small drops of water have succeeded in following the air stream, there are further walls that the air stream has to pass because the air stream has to go to four turns of each 90 degrees before the outdoor air is passed into the inner side of the air inlet. In this way it is achieved that five different wall sections will be in touch with the air where maybe even at the first wall, 99 per cent of the water droplets will hit the flange, and because the nature of water drops they are forming the wet surface at the flange, and gravity will remove the water. The same happens if sand parti- cles are following the air speed into the air inlet. All sand particles also have a mass much higher than the air molecules; therefore, the sand particles cannot follow the air around the corners in the channels. Therefore, the sand is hitting mostly the third flange where the sand is repelled out in the same direction from where it came whereby sand corn is completely rejected from passing through the air inlet. Only very small dust particles are able to pass the air inlet. These very small dust particles can be collected in a traditional filter because the amounts of dust particles that are passing through are extremely small.

The air inlet can comprise plurality mostly identical components, which components are fixed at least at the top and at the lover part to a frame. Because the air inlet can be formed as a plurality of identical components, this product can be produced at a very low cost. It also very easy to produce the individual component because it is simply a plate, which plate has been bent four times more or less in the same angle. Therefore, the individual components can be mass produced at a relatively low cost, and they can be fastened to a fixture by traditional fastening technologies such as screws or rivets, or it can be welded to the components. Each of the elements comprises a first flange placed in the flow direction of the inlet air, which first flange is formed as a perpendicular appendix to a second flange, which second flange is placed perpendicular to the inlet air, which second flange continues into a third flange, which third flange is formed parallel to the first flange, which third flange continues into a fourth flange which fourth flange is parallel to the second flange, which forth flange continues into a fifth flange which fifth flange is formed as an appendix pointing outwards against the direction of the air flow. Hereby it can be achieved that the element can be produced in a very simple manner and at a low cost, and that the elements just have to be placed on a fixture by which fixture a rather effi- cient air inlet is produced.

The length of the first flange is A, and the length of the second flange is 2* A, further is the length of the third flange 2* A, and further is the length of the fourth flange 2*A, and the fifth flange has the length A. In this way a rather simple profile of the elements can be achieved.

In a second embodiment for the invention each of the elements comprises a first flange placed in the flow direction of the inlet air, which first flange is formed as a perpendicular appendix to a second flange, which second flange is placed perpendicular to the inlet air, which second flange continues into a third flange, which third flange is formed parallel to the first flange, which third flange continues into a fourth flange which fourth flange forms an acute angle to the third flange, which forth flange continues into a fifth flange which fifth flange is formed as an appendix pointing outwards against the direction of the air flow. By forming the inner angle between the flanges in acute angles it is possible to achieve a better reflection of sand when sand is hitting the flange. In this way the sand will in all situations be directed outwards. The acute angle can also give a benefit in relation to preventing water because the water will be pressed into the acute angle and here two surfaces will guide the water droplets downwards.

Further in an second embodiment for the invention the length of the first flange is A, and the length of the second flange is 2*A, further is the length of the third flange 3* A, and further is the length of the fourth flange depending of the acute angle, and the fifth flange has the length A. Also by the alternative embodiment of the invention it is relatively simple to produce the elements simply because only one of the flanges have to be longer and the angle has to be changed into an acute angle. In a preferred embodiment of the pending patent application the surfaces of the flanges can be super hydrophilic. Hereby can be achieved, that any droplets of water or other liquids that hit the surface will shortly after wet a large area of the surface. If a further drop hits the already wet surface this drop will also disappear over the surface very shortly and the liquid will automatically be drained of the surface if there is any gravi- ty forces acting of the layer of water. Some super hydrophilic surfaces are able to col-, lect a rather big amount of water and probably after a period let the water evaporate again. In that way just as much water as they are receiving are being evaporated. This evaporation can lead to a temperature reduction at the surface. The super hydrophilic surfaces are especially effective if a strong air flow to an inlet is necessary. Any drops that touch the surface will automatically wet the surface and therefore even at higher air velocities the effective super hydrophilic surface will collect water drops highly effective.

Use of an air inlet as disclosed in one of the claims 1-6 or an inlet of cooling air for cooling an electronic outdoor installation. Hereby this invention can be used for for example mobile telephones and radio communication devices placed in an outdoor environment for trammitting signals for mobile telephone communication. The same invention could be used in housings for transformer systems which are also normally placed outdoor where also cooling air is necessary. A further use of this invention could be for many air condition systems where outdoor air has to be sucked into an evaporator and from there further into the indoor compartment. Because there will always be condensation of water at the evaporator, it is necessary in air condition systems to prevent dust or sand from getting access into the condition system because in the evaporator, the dust has to be removed. Probably most of the dust will automatically be removed together with the condensation water that will drop down from the evaporator, but in some situations a layer of dust or dirt could be formed on an evaporator which then has to be cleaned. The invention according to the pending application can be used in any place where fresh outdoor air has to be used, and where this air has to be sucked through a filtering device for industrial use or in housings. Description of the Drawing

Fig. 1 shows a first possible embodiment of the invention.

Fig. 2 shows a second embodiment of the invention.

Fig. 3 shows a sectional view through a few modules of the whole system.

Fig. 4 shows a third embodiment of the invention.

Fig. 5 shows a fourth embodiment of the invention.

Fig. 6 shows a fifth possible embodiment for the invention.

Fig. 7 discloses droplets of water and their behaviour at different surfaces.

Fig. 8 shows the behaviour of a drop of water at a super hydrophilic surface. Detailed Description of the Invention ;.

Fig. 1 shows an air inlet 2 which comprises an air inlet channel 4 which continues into a second channel 6 which runs perpendicularly to the inlet channel 4 which channel 6 continues after a further 90 degrees turn into a channel 8. This channel 8 is parallel to the inlet channel 4 but the air flow is in the opposite direction. From the channel 8, after a further 90 degrees turn, the air enters the outlet channel 10. The air inlet is formed of a number of elements 12 which elements are almost identical. The elements 12 comprise a first flange 14 and perpendicularly to the first flange, a second flange 16 is shown. And once again perpendicularly to the flange 16 a flange 18 is shown. Fur- ther perpendicularly to the flange 18 a flange 20 is shown which continues into a further perpendicular flange 22. In this way the individual element could be formed simply by bending a plate of steel and in that way forming an individual element. There is no doubt that an air inlet as shown at fig. 1 will be highly efficient because the degree of openings of the inlet is rather high in conjunction with traditional air inlets. But the inlet is highly effective because water drops will hit the flange 20 and the water drops will flow at the inner side of the flange 20 downwards because of gravity. Of course there is a corner towards the flange 22 and also a corner towards the flange 18. Maybe the water will partly flow in the corners. But the more water that is entering, the faster gravity will force the water to flow downwards. The same thing happens if sand corns are entering the inlet. If sand corns are entering the inlet at a high speed because of a high air velocity, the sand corns will hit the flange 20 and be reflected back again in the direction from which they came. Therefore, this invention is also highly efficient for preventing sand corns from entering the air inlet.

Fig. 2 shows the same invention as shown in fig. 1 but in a second embodiment which is indicated by 102. The inlet channel 104 continues into a second channel 106 which further continues into a channel 108 and into the outlet 110. The individual elements are indicated by 112. Again, the individual element is formed by a first flange 114 which continues after a 90 degrees turn into a second flange 116. Into a further 90 degrees turn the flange 116 continues into the flange 118. The flange 118 continues into a further section of a flange 120, but the flange 120 is bent in an acute angle 124. At least there is one flange, 122 which is pointing towards the inlet air. In operation, the embodiment shown in fig. 2 will be better and more efficient for repelling sand corns then the embodiment shown in fig. 1. Therefore, if this invention is to be used where there is often sand in the air, the embodiment of the invention shown in Fig. 2 is prob- ably more efficient than what is described in Fig. 1. However, the pending application is not to be limited to any of the definitions of angles, such as the acute angle 124 or to the 90 degrees angle shown in Fig. 1. Additional angles could also be used.

Fig. 3 shows an enlarged view of the first embodiment of the invention with the flang- es 14, 16, 18, 20, and 21. Especially with the embodiment shown in Fig. 3 it is possible to indicate that the distance A is used for the flanges 14 and 22, and a distance of 2A is used for the flanges 16, 18, and 20.

Fig. 4 shows an air inlet 200 which comprises an air inlet channel 204 which continues into a second channel 206 which runs mostly perpendicular to the inlet channel 204 which channel 206 continues after a further mostly perpendicular turn into a channel 208. From the channel 208 and after a further mostly perpendicular turn the air flow is flowing in the opposite direction. From the channel 208 and after a further turn, the air enters the outlet channel 210. The air inlet at the fig. 4 is formed of a number of ele- ments 212 which elements are mostly identical. The elements comprises a first flange 214 which flange 214 continues by a bending into one further flange 216 which flange 216 further by bending continues into a flange 218. The flange 218 is after a bending forming a further flange 220. After further bending of the material, a flange 222 is formed. The length of the flanges are defined by the first short flange 214 2* A and then probably the longer flange is then as 216 2* A in length further the flange 218 also has the length 2A which also is the length of the flange 220. The flange 222 then has the length A.

There is no doubt that deviation from the length indicated at fig. 4 is possible and also covered by the pending application.

In operation of air inlet as indicated at fig. 4 the incoming air is forced into a very weak change in its direction if it enters the inlet 204. Because of the corner that is formed between the inlet 204 and the channel 206 there is another big possibility that kind of vortex will exist around the corner. If a vortex occurs water drops or sand will be thrown out from the vortex in different directions until it hits one of the profiles. Further, if the air continues after the channel 206 into the channel 208 it is possible also in that corner to generate a vortex before the air afterwards leaves in 210. The affectivity of the vortex depends of course of the speed of the air flow. But if the air inlet is used where cooling air is sucked into a large cooling system the velocity of incoming air is relative high. Fig. 5 describes the same invention but now is the angular displacement of the profile opposite to what is seen at fig. 4. All numbers of the drawings is 100 higher at fig. 4 otherwise it is more or less identical operation from the embodiment of fig. 4 and fig. 5. Also at fig. 5 the air inlet 300 can generate vortexes if the air inlet velocity is relative high.

Fig. 6 discloses a further alternative embodiment for an air inlet 400. The air inlet comprises an inlet channel 404 which continues after a first turn into a channel 406 which further continues into a channel 408 and ends with an outlet 410. The air inlet 400 comprises a number of flanges at the inlet 414 continuing in 412 which continues into a flange 408 and which further continues into a flange 420 ending in the flange 422. In operation an inlet as indicated at fig. 6 where the inlet opening is turned to a direction approx. 45 degrees to the flow direction of incoming air, there is no doubt that incoming air in the channel 404 will be forced to turn nearly 90 degrees whereby water droplets, sand particles or other mechanical particles flowing in the wind such as maybe snow will hit the wall and where water drops probably would wet the surface, the sand will loose so much of its kinetic energy that it falls down by gravity where further contact with the flanges will occur in each of the 90 degrees turns that the air flow has to go through. Probably the invention indicated at fig. 6 will be one of the best of the different examples shown for preventing against sand or maybe against snow.

In a typical air inlet different inlets could be combined forming row of maybe two or three of the different embodiments. Especially if fig÷ disclosure is combined with fig. 6 there will be a 90 degrees turn in the direction from the outlet from the channel 207 at fig. 4 to the inlet 404 at the fig. 6. Many different combinations of the different inlets as here indicated could be used in a more row air inlet. In many situations up to 90 per cent of water droplets and maybe an even higher percentage of sand particles will be picked up in the first inlet. Continuing into a second air inlet will probably reduce the content of water or sand particles sufficient much more so it is nearly 100 per cent. An open question for inlets for cooling purposes for electronic circuits is of course the air flow resistance that occurs during the inlet. The inlets here indicated there would be only a very slight increase of the air flow resistance by combining two of the different inlet filters.

Fig. 7 shows a surface 502 which could be a surface of one of the flanges previous mentioned. At the surface is placed a drop 504. Because the surface 502 is hydrophilic a relative good wetting is performed at the surface. It is indicated that the contact angle between the water droplet and the surface is approx. 10 degrees. At the next figure which also is part of fig. 7 the surface is numbered 506 and a drop is indicated as 508. The surface 506 is a hydrophobic surface where the surface tension in the water drop forms the drop 508 with a contact angle of approx. 7 degrees indicated as 510. It is easy to understand that by high velocity of incoming air the drops with high surface attention as indicated as 508 they can roll along the surface 506 and in that way follow the air stream to different labyrinths and continue as drops when they are leaving the last surface. It is therefore very important that the surface is hydrophilic as indicated as the surface 502.

Fig. 8 also indicates a surface 602 and a drop wetting the surface 604. Because the surface 602 is super hydrophilic the water drop is wetting the surface totally.

As indicated it is important for this invention that the surfaces at the flanges are hydrophilic or super hydrophilic. In an alternative embodiment for the invention the air inlet can be placed in an angle divagating from vertical orientation. ,

The air inlet as disclosed in the figures 1-3 can also be used as an air outlet. The orientation of an air outlet can be any angle between horizontal and vertical.

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Tests have shown that certain properties related to the surface of the air inlet are important in. order to achieve a satisfying separation of droplets of liquids, especially water, from the air passing through the air inlet. In order to obtain a satisfying removal of water, the surface of the air inlet, or at least a part thereof, should be hydrophilic or super hydrophilic.

A surface is hydrophilic if the contact angle between the water droplet and the surface of the material is less than 70°. In case of a contact angle close to 0°, the surface is defined as super hydrophilic.

A hydrophilic surface or a super hydrophilic surface on the air inlet will result in a low contact angle of the water droplets on the surface of the flanges 14, 16, 18, 20, 1 14, 1 16, 118 and 120. This results in that the water droplets are less likely torn off the surface by the air passing through the air inlet 2, 102 when compared to less hydrophilic or hydrophobic surfaces. In addition, a hydrophilic or a super hydrophilic surface results in wetting of the surface rather than droplets of water on the surfaces of the air inlet, when the water droplets hit a surface of one of the flanges 14, 16, 18, 20, 1 14, 116, 118 and 120 of the air inlet 2, 102. This further results in that the water is drained from the surfaces more efficiently and more quickly.

An air inlet providing a suitable hydrophilic surface is preferably made of anodised aluminium. It is preferred that the profiles from which the air inlet is made are anodised after being shaped. Alternatively, the entire air inlet is formed into its final shaped before being anodised. Optionally, the air inlet or the profiles for making the air inlet are polished chemically or electrolytically prior to being anodised.

Alternatively the air inlet 2, 102 or the profiles 12, 112 from which the air inlet is made comprises a surface of a metal foam material or are made, of a metal foam material, e.g. of alumimum or another suitable metal or alloy, e.g. steel, cupper, brass or the like, preferably in a closed cell structure in order to eliminate any air flow through the metal foam. The surface of the metal foam will act as a wick or sponge and fill the pores in the surface of the metal foam with water, which results in that the surface acts highly or super hydrophilic.

Alternatively, the air inlet 2, 102 or the profiles 12, 112 used for making the air inlet 2, 102 are made from galvanised steel, i.e. a zinc or alu-zinc surface is provided on the air inlet 2, 102 or the profiles 12, 112. This surface also provides a sufficiently hydrophilic surface on the flanges 14, 16, 18, 20, 114, 116, 118 and 120.

In yet another version, the air inlet 2, 102, is made of profiles made of a metal core which is coated with a layer of a resin or, alternatively, the profiles are made of a resin, or the entire air inlet is cast or extruded from a resin such as homo- or copolymers of polyethylene and/or polypropylene, or homo- or copolymers of polyester, polycarbonate or acrylics. The resin should be hydrophilic, either by nature, by coating it with a hydrophilic coating (as described below) or by adding one or more additives providing a hydrophilic surface on the resin. Examples of hydrophilic resins are e.g. certain polymers based on polyurethane. An example of a suitable additive providing a hydrophilic surface on an air inlet of thermoplastics, e.g. polypropylene, is Atmer™ sold by Croda. A coating which renders the surface hydrophilic or super hydrophilic may also be applied to the surfaces of the air inlet which are in contact with the air. A hydrophilic coating may e.g. be conventional so called "anti-fog" coatings used on glass, windshields, mirrors etc. Alternatively a hydrophilic coating, e.g. based on hydrophilic pol- ysilanes, or hydrophilic polyurethanes (e.g. based on Hypol™ prepolymers sold by DOW) may be used. Another example of a suitable hydrophilic coating is e.g. a high performance anti-fog coating (HTAF-308) marketed by Abrisa Technologies, which will provide suitable hydrophilic coatings on an air inlet made of e.g. polyester, polycarbonate or acrylics upon curing.

A suitable super hydrophilic surface is obtainable by applying nanostructures to the surfaces of the air inlet. A suitable super hydrophilic surface is obtainable by coating the surfaces of the air inlet with a layer of titanium dioxide particles, especially titanium oxide particles having a size in nano scale, to the surface of the air inlet, e.g by applying a layer of a coating comprising the titanium dioxide, particles. The titanium dioxide absorbs UV light, which renders the surface super hydrophilic. In the air inlet according to the present invention, at surface treatment comprising titatuim dioxide particles is thus advantageous, especially if the air inlet is subjected to sunlight, e.g by bemg installed in an outer wall, since at least the part of the surface which is exposed to sunlight will become super hydrophilic. Thus at least the surface of the flanges 14, 16, 18, 20, 114, 1 16, 118 and 120, which are subjected close to the inlet region of the air channel through the air inlet 2, 102, will be exposed to sunlight and will become super hydrophilic. These surfaces of the air inlet are also the surfaces towards which the majority of the water droplets will collide.

In addition, the titanium dioxide coating is also able to degrade impurities adhering to the surfaces by photo catalytic degradation. Thus an air inlet coated with titanium dioxide particles will also obtain a "self- cleaning" effect.