SE533713C2 - Supply air - Google Patents

Description

533 713 displacing ventilation, whereby a low-velocity air stream in the vicinity of the floor displaces relatively hot air in the room and provides an orderly air flow upwards to the upper part of the room, where the relatively hot and possibly polluted air is extracted from nearby air openings. of the roof.

A disadvantage of such “displacing” ventilation, with a low-velocity air flow, is that it is necessary to provide very large supply air diffusers for supplying the necessary low-velocity air flow to the room.

OBJECT OF THE INVENTION Against this background, the present invention aims to provide efficient, comfortable ventilation in a room next to a supply air diffuser which has moderate dimensions and is suitable for mounting in the floor and yet provides an efficient ventilation which is comfortable for persons. staying in the room.

Summary of the invention The main object stated above is achieved by means of a supply air device provided with air-guiding profile elements, curved to a tangent angle at the outlet end which is less than 15 ° relative to the floor surface, so that the air flow from the ventilation grille unit is diverted to a substantially horizontal air flow. a stable flow layer at a vertical distance of at least 20 mm and not more than 100 mm above the floor surface, the flow rate of the air stream coming from the floor, at the outlet end of the ventilation duct unit, being at least 2.5 m / s, so that the resulting horizontal air flow will proceed along the floor with a large amount of movement or motive force In this way, the supplied fresh air will propagate in one (momentum). rather narrow layer along the floor, and this layer reaches areas which are in the room which are located at a relatively large distance from the supply air device. This also applies if the air flow hits a wall or other object, where laterally, the air flow bounces back or is deflected in due to the large amount of movement of the air flow.

In order to promote a uniform air flow at the outlet ends of the air-guiding profile elements, these outlet ends can be tapered to an edge extending in the longitudinal direction.

Such an edge can be cut off so that it forms a vertical edge surface, or these outlet ends can be softly rounded.

At the lower and upper sides of this longitudinally extending edge, the key direction may be less than 10 ° relative to the floor surface, possibly less than 5 ° at the top and less than 10 ° at the bottom, and possibly also substantially parallel to the floor surface (which is normally horizontal).

As indicated above, the stable flow layer formed at the downstream side of the supply air device can be even narrower, for example in a range between 30 mm and 90 mm above the floor.

It is possible to mount the supply air device relatively close to a wall in the room and to direct the outflowing air from the ventilation grille away from the wall. Alternatively, the outflowing air can be directed towards such a wall and allow the air flow to bounce back into the room. In this way the air velocity is reduced, but the amount of movement of the air stream is maintained, and the fresh air will be distributed efficiently in the lower part of the room. Such a ventilation arrangement is perceived as comfortable for people staying in the room. The distance between the ventilation grille and an adjacent wall can amount to 0.2-1.0 m (possibly between 0.3-0.9 m) in either of these two possible arrangements. The air flow velocity at the outlet end of the ventilation grille unit can be in the range 2.5 m / s to 6.0 m / s, possibly between 3.0 and 5.0 m / s.

The ventilation grille unit may comprise at least two air-guiding profile elements made of an aluminum alloy or other durable material, which is easy to manufacture.

According to a further advantageous aspect of the present invention, the air guiding elements may comprise a step-like irregularity along their length, which forms a step in Such a step may be formed on either side or on both sides of the pro-direction of the upward flowing air. the file element, i.e. on its concave side and / or its convex side. In a preferred embodiment, there is such a step on both sides.

These and other features of the invention are set forth in the appended claims and will be apparent from the following detailed description.

Brief Description of the Drawings The invention will be explained in more detail below with reference to the accompanying drawings, which illustrate an embodiment of the invention.

Figure 1 shows in a top view, a ventilation grid unit which forms part of a supply air device according to the invention; Figure 2 shows a supply air device according to the invention, in a vertical section through the floor of a room to be ventilated; 10 15 20 25 30 533 713 Figure 3 shows on a larger scale a modified ventilation grid unit with only a small number of air-controlling profile elements.

Detailed description of a preferred embodiment Figures 1 and 2 show a supply air device according to the invention, which is mounted in a floor in a room to be ventilated. The upper floor surface 1 is horizontal. Only a part of the floor is shown in figure 2. It is assumed that exhaust air diffusers are arranged next to the ceiling of the room.

A box-shaped chamber 2 is built in below the floor surface 1, and in this chamber an elongate supply air diffuser is arranged below the floor surface 1, for example of the type described in Swedish patent application no. 0900359-1 (Inventiair AB). Thus, the supply air device comprises a housing 3, a supply pipe 4 for supplying air air and a supply air opening 5 directed horizontally towards the adjacent air supply chamber 6. At the top of this air supply chamber 6 a ventilation grid unit 7 is mounted with its upper surface portion 8f, 9a in line with the floor surface 1. The ventilation grille unit 7 is also shown from above in figure 1. Typically, the ventilation grille unit has a length. of 0.5 to 1.0 m and a width of 0.2 to 0.5 m.

The air guiding profile elements 8 have a height of 30 mm to 40 mm and the free distance between two adjacent guide profile elements 8 is between 15 mm and 25 mm, measured as the free distance between them at the uppermost and lowest places.

The profile elements 8 are held together by transverse holding elements 12, for example in the form of tubes or rods.

In principle, fresh air is supplied through the supply pipe 4, whereby (arrow A), and then along the floor the air flows out through the opening 5 the ventilation grille 7 (arrows B) upwards through A 10 20 25 30 533 713 according to the arrows C. Thus the upward flowing air will be controlled and are deflected by means of the curved air-guiding profile elements 8 which form part of the ventilation grid unit 7. Figure 3 shows these air-guiding profile elements 8 on a larger scale. Each profile element, which is made of a durable aluminum alloy, has a lower, substantially straight portion 8a, a connecting, slightly curved middle portion 8b, a step portion 8c, a connecting, curved upper portion 8d and an upper end portion 8e, which tapers to a longitudinally extending edge.

The step portion 8c has a step surface on both sides, ie on the concave side (on the left in Figure 3) and also on the convex side (on the right in Figure 3). Thanks to the step portion 8c, the effective curvature of the profile element will increase at the upper part of the profile element, and there is a further effective curvature of the longitudinally extending edge 8e.

As can be seen from Figure 3, there is an upper, horizontal surface portion 8f and a lower, very short surface portion 8g, which is likewise horizontal. Thus, the surface portions 8f and 8g in this embodiment are substantially parallel to the floor surface 1. As indicated above, these surface portions, corresponding to 8f and 8g, may alternatively be oriented at a small angle relative to the floor surface, such as up to 15 °. , possibly less than 5 ° at the upper side (8f) and less than 10 ° at the lower side (8g).

It will be appreciated that the air flowing upwards through the ventilation grille unit 7 (arrows B in Figure 2) will be increasingly deflected by the profile element portions 8b, 8c, 8d and 8e, so that the resulting air flow above the ventilation grille unit '7 is approximately horizontal, as illustrated by the arrows C in Figure 2. such air flow. It is well known that one which flows substantially parallel along a surface (floor surface 1) will be retained at this surface and maintain its direction parallel with the surface, through the so-called

Coanda effects.

Practical tests have shown that the air flow along the floor surface 1 will be limited to a layer at a vertical distance above the floor between 20 mm and 100 mm, in particular between 30 mm and 90 mm.

In addition to being deflected laterally by the air guiding profile elements 8, the upwardly flowing air (arrows B) will be affected by the step profile portion 8c which thereby causes a certain turbulence locally in the air flow. This turbulence will promote an efficient interaction between the horizontal air flow C along the floor, while maintaining the momentum or motive force of the horizontal air flow and ensuring a uniform distribution of the fresh air throughout the room. Persons in the room will cause a local upward flow of convection air, and this upward air flow will be effectively replaced by fresh air from below. Thanks to the diffuse turbulence in the fresh air flow, any difference in temperature between the fresh air and the air in the room will be equalized. belt, Thus the room climate becomes pleasant and comfortable - and you do not feel any draft even if the horizontal air flow has a relatively high speed. As mentioned above, this air flow is limited to a rather narrow layer very close to the floor.

The supply air can have approximately the same temperature as the average drop at room temperature, because the room temperature is at a moderate level, such as 20 ° C. Normally, however, the supply of slightly warmer air, in cold climates, or cooled is required. 10 20 25 30 533 713 net can be achieved by. heat exchanger 10, the supply air diffuser. Further arranged, as a practical measure, the profile elements 9 located at one end of the ventilation grid unit 7 may be provided with an extended horizontal surface 9a adjacent to the floor surface 1 and covering a dead zone of the outlet opening of the ventilation grid unit 7.

Claims (14)

533 'H3 PATENT REQUIREMENTS Supply air device for supplying fresh air to the floor of a room to be ventilated, comprising a ventilation grid unit (7) arranged substantially flush with a floor surface (1), which ventilation grid unit is provided with a set of air-guiding profile elements (8). ) which are oriented parallel to each other and have a curved cross-sectional profile, so that they direct an upwardly flowing air stream (B) in a direction with a component (C) parallel to said floor surface, characterized in that - said air-guiding profile element ( 8) are curved to a tangential angle at each outlet end (8e) which is less than 15 ° relative to said floor surface (1), so that the air flowing out of the ventilation grid unit (7) is deflected to a substantially horizontal air flow (C) which forms a stable flow layer at a vertical distance of at least 20 mm and not more than 100 mm above the floor surface (1), - the flow rate of said upflowing air, at the outlet end of the ventilation grille (7), is at least 2.5 m / s, so that the resulting horizontal air flow (C) propagates along the floor surface (1) with a large kinetic force, and - each of said air-guiding profile elements comprises takes a step-like irregularity (8c) along its length, which forms a step in the direction of the upwardly flowing air stream, at least on one side of the profile element (8), which step causes a turbulence in said upwardly flowing air stream, so that mixing and heat exchange promoted between said horizontal air flow (C) and the ambient air in said room. 533 713 lo Supply air diffuser according to claim 1, wherein said outlet end and said profile element are tapered to an edge (8e) extending in the longitudinal direction. Supply air diffuser according to claim 2, wherein said longitudinally extending edge (8e) has a tangential direction, at the lower and upper sides, which is less than 10 ° relative to said floor surface. Supply air diffuser according to claim 3, wherein said longitudinally extending edge (8e) has a tangential direction which is less than 5 ° at the upper side and less than 10 ° at the lower side, relative to said floor surface (1) . Supply air diffuser according to claim 4, wherein the tangential direction is substantially parallel to said floor surface (1) at the upper side and also at the lower side of said edge (8e) extending in the longitudinal direction. Supply air diffuser according to claim 1, wherein said vertical distance above the floor is between 30 mm and 90 mm. Supply air diffuser according to claim 1, wherein said ventilation grille unit (7) is arranged next to a wall in the room, said air guiding profile element (8, 9) extending parallel to said wall, and said horizontal air flow (C) being directed towards or away from said wall, the horizontal distance between said ventilation grid unit (7) and said wall being 0.2 - 1.0 m, and the flow velocity of said horizontal air flow (C), at the outlet end of said ventilation grid unit, is in the range 2, 5 m / s to 6.0 m / S. 533 713 // Supply air diffuser according to claim 7, wherein said horizontal distance to said wall is between 0.3 and 0.9 m. Supply air diffuser according to claim 1, wherein said flow rate is between 3.0 and 5.0 m / s. Supply air diffuser according to claim 1, wherein said ventilation grille unit comprises at least two air-guiding profile elements (8) made of an aluminum alloy. 11. ll. Supply air diffuser according to claim 1, wherein each of said air-guiding profile elements (8) comprises a step-like irregularity (8c) at its concavely curved side and at its convexly curved side. Supply air diffuser according to claim 1, wherein said ventilation grid unit (7) has a length of 0.5 to 1.0 m and a width of 0.2 to 0.5 m. Supply air diffuser according to claim 1, wherein each of the air guiding profile elements (8) has a height of 30 mm to 40 mm, there being a free distance of 15 mm to 25 nmx between. the two adjacent guide profile elements, measured as the free distance between them at the upper and lower ends (8a, 8e). Supply air diffuser according to claim 1, wherein said ventilation grille unit (17) is arranged at a box-like air supply unit (3) with an air supply opening (15) which supplies fresh air to an air supply chamber (6), the ventilation grille unit forming an upper lid on said box-like air supply chamber (6).