The invention relates to an apparatus for the inlet of air into a space.

BACKGROUND

Many buildings, including e.g. theaters, swimming pools, and industrial buildings, are provided with air conditioning and/or air supply installations to realize an agreeable environmental climate in the interior spaces of the building. This is of relevance not only to compliance with the current rules and regulations, but also to the well-being of the visitors and/or staff of the buildings. The existing installations often comprise a climate installation for conditioning air, such as regulating the temperature and/or the air humidity.

An example of this concerns a space heating unit which is described in FR 2 914 401. Depending on temperature measurements by temperature sensors at three different air sources, the three fans are actuated as well as a motor for adjusting a valve member.

FR 2 855 251 concerns a valve unit for regulating the extraction force. With the aid of the valve unit described therein, extraction can be put in a high and a low position through adjustment of a valve in the valve unit. This valve unit has nothing to do with the inlet of air.

In general, it holds that the conditioned air, after climatizing, can be conducted with air supply installations through main channels to building spaces. In the building spaces, subchannels are arranged which are used for distributing the air over inlet grates or inlet openings in the building space. Also, the building spaces may be provided with air after- treatment units, such as fan convectors, which are coupled to the main channels and which are used for distributing the air via the subchannels to the inlet grates or inlet openings in the building space. The air is then blown through the inlet grates or inlet openings into the building spaces as a continuous air stream.

The disadvantage of these existing systems is that no proper mixing takes place of the air that is already present in the space and the air that is supplied to the space. This leads to temperature differences and draught in the space, by which the residential climate is adversely affected. The lack of mixing leads, inter alia, to temperature differences and/or draught in the space. As a consequence, the residential chmate for persons present in the space is adversely affected and complaints from visitors and staff about the indoor climate may arise.

SUMMARY

The invention is aimed at eliminating these disadvantages of existing systems, while preserving the advantages of existing systems. To this end, the invention provides an apparatus for inlet of air in a space, comprising:

- a housing comprising a plurality of walls and which bound an air distributing chamber;

at least one air intake opening which is provided in one of the walls;

- at least two air inlet openings which each terminate in a space whose air it to be refreshed and wherein each air inlet opening forms an inlet zone there, so that the apparatus defines a plurality of inlet zones, the air inlet openings being bringable into fluid communication with the air distributing chamber;

- a valve assembly comprising a valve actuator and at least one valve member, wherein the at least one valve member is adjustable with the valve actuator, wherein the valve actuator, in use of the apparatus, continuously or intermittently adjusts the position of the at least one valve member for alternately interrupting at least in part the supply of air to a different one of the air inlet openings, such that the inlet of air in the space repeatedly takes place via different ones of the plurality of air inlet zones.

Through the operation of the apparatus according to the invention, a better mixing is achieved between the air supphed to the space and the air already present in the space, thereby preventing (relatively large) temperature differences and draught in the space. Accordingly, in the use of the apparatus according to the invention, a homogeneous condition of the air in the space is realized. By alternately interrupting the supply of air to a different one of the air inlet openings, the air is let into the space alternately via different ones of the air inlet zones, while moreover in each of the air inlet zones a turbulent flow pattern occurs. These turbulent flow patterns cause an irregular air flow pattern in the space, which leads to a proper mixing of the air already present in the space and the air let into the space, without draught arising. Due to the homogeneous composition of the air in the space, (relatively large) temperature differences in the space are absent, and the chance of draught arising in the space is minimized. An additional advantage is that the air can be let into the space with a relatively low speed, while at the same time a proper mixing is achieved.

The apparatus according to the invention can be simply connected to existing air channels and/or air treatment devices, such as air

conditioners or fan convectors, but can also be integrated in new air channels or air treatment devices to be newly installed, such as air conditioners or fan convectors. In such a case, a single apparatus may be included, but, for instance, including multiple apparatuses in a new air treatment and supply system in a building may also be considered.

Further, the housing of the apparatus may be implemented in various geometric shapes, thus allowing the shape of the apparatus to be adapted to the requirements and layout of the space in which the apparatus can be placed. This is especially advantageous in spaces where a lot of other equipment needs to be placed, such as, for example, halls of theaters or music halls. The apparatus may be designed to be of a relatively limited size, so that it could also be installed above a modular ceihng in a space, with the air inlet openings and the associated air inlet zones being provided in the modular ceiling in such a way that only the air inlet openings terminate (and hence are visible) in the space in which the air is to be refreshed.

It is noted that the problem for which this invention provides the solution, namely, creating a variable flow pattern in a space, is not addressed in the earlier -mentioned French publication FR'251. The valve unit known from this publication has only one outlet. Consequently, the following features of the present invention are lacking in FR'251:

- wherein the apparatus is provided with at least two air inlet openings which terminate in a space whose air is to be refreshed and each form an inlet zone there, so that the apparatus determines a plurality of inlet zones; and

- wherein the valve actuator, in use of the apparatus, continuously or intermittently adjusts the position of the at least one valve member for alternately interrupting at least in part the supply of air to a different one of the air inlet openings, such that the inlet of air in the space repeatedly takes place via different ones of the plurality of air inlet zones.

The other above-mentioned publication FR'401 has a different object than the apparatus according to the present invention, namely, the infeed of fresh air into a space, which air originates from different sources with different temperatures. Depending on the temperatures of the various sources, the fresh air is drawn from one of the sources mentioned and by operation of an internal valve in the apparatus and with the aid of control of fans in the apparatus, the fresh air coming from the desired source is drawn in and passed into the space. In FR'401 too, the above-described features of claim 1 of the present invention are lacking. There is no question of any continuous or intermittent adjustment of at least one valve member for alternately interrupting at least in part the supply of air to a different one of the air inlet openings, such that the inlet of air in the space repeatedly takes place via different ones of the plurality of air inlet zones.

The apparatus according to the invention can be further elaborated in various ways. Further elaborations of the invention are described in the subclaims and will hereinafter be further clarified on the basis of an example, with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1A shows a schematic side view of a first example of an apparatus;

Figure IB shows a schematic sectional view along line IB-IB of Figure 1A;

Figure 2 A shows a schematic side view of a second example of the apparatus;

Figure 2B shows a schematic sectional view along line IIB-IIB of Figure 2A;

Figure 3 A shows a schematic side view of a third example of the apparatus according to the invention;

Figure 3B shows a schematic sectional view along line IIIB-IIIB of Figure 3A; and

Figure 4 shows a similar view to Figure 3B of a fourth example of an apparatus.

Figure 5 shows a perspective view of a fifth example of an apparatus;

Figure 6A shows a schematic perspective view of the housing of

Figure 5;

Figure 6B shows a schematic perspective view of a valve member according to the apparatus of Figure 5; Figure 7 shows a top plan view of the housing of the apparatus of

Figure 5;

Figure 8A shows a sectional view along the line VIIIA-VIIIA of

Figure 7;

Figure 8B shows a sectional view along the line VIIIB-VIIIB of

Figure 7.

Figure 9A shows a perspective view of a sixth example of an apparatus with shutter valve assemblies, depicting the shutter valve assembly that is in a closed position;

Figure 9B shows a perspective view of the example of Figure 9A, depicting the shutter valve assembly that is in an open position;

Figure 9C shows a side view of the example of Figures 9A and 9B; and

Figure 9D shows a sectional view along line IXD-IXD of Figure 9C.

DETAILED DESCRIPTION

Figures 1-8 show examples of apparatuses according to the invention in which various embodiments such as they are described in the subclaims are embodied. It is noted that the embodiments can also be applied independently of each other and that the invention is not limited to the examples shown in the figures. The reference numerals in the detailed description and the claims are for clarification but have no limiting effect in any way. An embodiment, of course, may also be implemented in a different manner than represented in the examples that are shown in the figures.

Figures 1-9 show examples of an apparatus according to the invention. In the most general terms, the invention provides an apparatus 10 for the inlet of air into a space 12. The apparatus includes a housing 14 comprising a plurality of walls 16a, 16b, 16c, 16d, 16e and which bound an air distributing chamber. In a wall 16a at least one air intake opening 20 is provided. In addition, the apparatus is provided with at least two air inlet openings 32 which each terminate in a space 12 whose air is to be refreshed. Each air inlet opening 32 forms an inlet zone 34 in that space, so that the apparatus 10 determines a plurality of inlet zones 34. The air inlet openings 32 are bringable into fluid communication with the air distributing chamber mentioned. To that end, the apparatus is provided with a valve assembly comprising a valve actuator 28, or 58, and at least one valve member 30, or 50. The at least one valve member 30; 50 is adjustable with the valve actuator 28 or 58. In use of the apparatus 10, the valve actuator 28 or 58 continuously or intermittently adjusts the position of the at least one valve member 30; 50 for alternately interrupting the supply of air a different one of the air inlet openings 32. What is thus accomplished is that the inlet of air in the space 12 repeatedly takes place via different ones of the plurality of air inlet zones 34.

In an embodiment, of which examples are shown in Figures 1-8, the apparatus may include a valve chamber 36 which is included in the housing 14, more particularly in the air distributing chamber thereof. The air intake opening 20 then terminates in the valve chamber 36. The valve chamber 36 is provided with at least two valve openings 38, which are each in fluid communication with an associated air inlet opening 32. In the valve chamber 36 a valve member 30 is disposed. The valve member 30 is so disposed that, depending on its position, it at least partly shuts off at least one of the at least two valve openings 38. Each valve opening 38 is connected with at least one air inlet assembly 24, each air inlet assembly 24 being provided with at least one earlier-mentioned air inlet opening 32.

With such an embodiment too, it is brought about that the inlet of air in the space 12 repeatedly takes place via different ones of the air inlet zones 34.

The operation of this embodiment of the apparatus 10 is as follows. The air intake opening 20 of the apparatus and an air inlet assembly 24 which is associated with a valve opening 38 of the apparatus 10 are connected by an open fluid communication when the respective valve opening 38 is not shut off by a valve member 30 of the valve assembly 26. In that opened valve condition, therefore, due to the open fluid communication between an air inlet assembly 24 and the air intake opening 20, there arises a continuous air stream through the respective air inlet assembly 24 and the air inlet openings 32 present therein which form an associated air inlet zone 34. The pressure in the air inlet assembly 24 is then substantially constant. If the valve member 30 is adjusted, the passage area of the valve opening 38 decreases, preferably until the fluid communication between the air intake opening 20 and the air inlet assembly 24 is substantially completely shut off in that the valve opening 38 is closed off by the valve member 30. As a result, a pressure change occurs in the respective air inlet assembly 24 and the amount of air that is let into the space 12 via that air inlet zone 34 decreases. Once the fluid communication between the air intake opening 20 and the air inlet assembly 24 is restored and thereupon the passage area of the valve opening 38 between the air intake opening 20 and the air inlet assembly 24 increases as a result of adjustment of the valve member 30, the pressure in the air inlet assembly 24 changes to the previous, higher value and the amount of air that is let into the space 12 via that air inlet assembly 24 and the associated air inlet zone 34 increases. The varying air pressure in the air inlet assembly 24 leads to a varying inlet speed of the air that is let into the space 12 via the air inlet zone 34. The varying inlet speed thereby creates a turbulent flow in the air inlet zone 34, which is favorable to the mixing of the air let into the space with the air already present in the space.

Various embodiments of the apparatus 10 are possible. For instance, the housing 14 of the apparatus and the air inlet assemblies 24 can be implemented in various manners. The air inlet assemblies 24 may be integrally incorporated in the housing 14, but may also be connected with the housing 14 via tubes or channels. In addition, the housing may be implemented in various geometric shapes. Two examples of an apparatus 10 according to the invention with a cylindrical housing 14 and air inlet assemblies 24 integrally incorporated in the housing 14 are represented in the Figures la, lb and Figures 2a, 2b. A third example and a fourth example of an apparatus 10 according to the invention with a substantially block-shaped housing 14 and air inlet assemblies 24 integrally incorporated in the housing 14 are represented in Figures 3a and 3b and Figure 4. A fifth example of an apparatus 10 according to the invention with a different geometric shape is represented in Figures 5-8. In this fifth example, the air inlet assemblies 24 are connected to the housing 14 via channels 18a and do not form an integral part of the housing 14.

Further, the valve member, too, may be implemented in various manners. For instance, it is possible to choose a valve member that can shut off only one valve opening 38 at a time, but also to choose a valve member that can shut off several valve openings 38 at the same time. As shown in Figures 1-3, the valve member 30 can for instance comprise a single circular segment-shaped shutoff part to shut off one valve opening 38. An example of a valve member 30 that can shut off several valve openings 38 at the same time is shown in Figure 4, with the valve member 30 comprising plate- shaped parts. To that end, the valve member 30 of Figure 4 is provided with two circular segment-shaped shutoff parts. The Figures 5-8 show a valve member 30 that comprises several plate-shaped shutoff parts, which are so disposed that in each case one of the valve openings 38 is shut off. It is to be noted that the orientation of the shutoff parts of the valve member 30, such as for instance shown in Figure 6b, can also be arranged differently, for instance such that several valve openings 38 can be shut off at the same time.

A last example of an embodiment is shown in Figures 9A-9D. Here, the valve assembly comprises a plurality of shutter valve assemblies. The advantages of the apparatus according to the invention have been described hereinabove in the summary, to which reference is made here.

In an embodiment, of which an example is shown in Figure 5, each air inlet assembly 24 can comprise an air channel 18a and an air inlet unit 18b. The air channel 18a is connected by an inlet thereof to the valve opening 38 associated with the respective air inlet assembly 24. An outlet of the air channel 18a is connected to the air inlet unit 18b of the air inlet assembly 24. The air inlet unit 18b includes the at least one air inlet opening 32 of that air inlet assembly 24.

By the use of air channels 18a with air inlet units 18b connected thereto, such as, for example, inlet grates, the housing 14 does not need to be (visibly) installed in the space 12 into which the air is fed. For instance, the housing 14 can be installed above a modular ceiling, where only the air inlet units 18b are visible at the underside of the modular ceiling. The remaining part of the apparatus 10, such as the housing 14 and the air channels 18a, is not visible to persons in the space 12. This is esthetically attractive for inter alia office buildings. The apparatus in this embodiment can also be easily included in existing systems, for instance by placing the apparatus between the main channels and subchannels of a building space. This renders the costs of fitting the apparatus relatively low.

In an embodiment, of which examples are shown in Figures 1-4, each air inlet assembly 24 can comprise a compartment in the housing 14. The compartments are separated from each other by partitions 22 which are included in the housing 14. The at least one air inlet opening 32 of each air inlet assembly 24 is provided in at least one of the above-mentioned walls of the housing 14 which bound the respective compartment.

In this embodiment, the air inlet assemblies 24 are included in the housing 14 and form an integral part thereof. The apparatus 10 is thus one single installation which can be easily installed at a location. The advantage of this embodiment is that cleaning the apparatus 10 is relatively easy, because the air inlet assemblies 24 do not comprise any air channels of some length. In an embodiment, each compartment can have a substantially equal size.

By making all compartments of an equal size, a contribution is made to the proportional distribution of the air stream towards all inlet openings 32 of the apparatus 10. This leads to a proportional distribution of the inlet air to the different inlet zones 34.

In an embodiment, of which an example is shown in Figures 1-4, the housing 14 may be provided with a first 16a and a second end wall 16b which are positioned opposite each other and which are mutually connected by at least one sidewall 16c. The air intake opening 20 may be provided in or near a center of the first end wall 16a of the housing 14. The valve member 30 of the valve assembly 26 may be disposed in the valve chamber 36 in a manner rotatable about a central axis H. The valve member 30 in each case covers at least one of the valve openings 38 at least partly, with coverage depending on the rotational position of the valve member 30 in the valve chamber 36.

In this embodiment, shutting off at least a part of one compartment can be carried out simply and efficiently. The rotatable valve member 30 of the valve assembly 26 in each case and successively shuts off at least a portion of one of the valve openings 38, so that an ever-varying pressure in the respective compartment is created. This ever -varying pressure leads to a variation in air inlet speed and hence to turbulence of the air in the space 12 near the air inlet zones 34, resulting in better mixing with the air present in the space 12. The rotation of the valve member 30 ensures that in each case a different compartment is shut off. This rotation can be continuous or intermittent.

In an embodiment, of which an example is shown in Figures 1-4, the valve member 30, viewed in the direction of the central axis H, can have a substantially circular segment-shaped configuration. The valve member 30 has, in the direction of the central axis H, a thickness D which

substantially corresponds to a distance between the two end walls 16a, 16b. An example of such a valve member 30 is shown in the Figures 1-3. The advantage of a circular segment-shaped valve member 30 is that the compartments can be efficiently shut off without interrupting or hindering the air stream to the other compartments.

Obviously, the valve member 30 may also be designed differently. To be considered here, for example, are two circular segment-shaped parts, the angular points of which are connected to each other. An alternative valve member 30, of which an example is shown in Figure 4, can consist of two circular segment-shaped plate parts having a height D and a surface equal to the surface of the valve opening 38. The plate parts of the valve member 30 are mutually interconnected by a connecting plate or bar. This connecting plate or bar is connected with the valve actuator 28, which is arranged to rotate the valve member 30. During the rotation of the valve member 30, two opposite compartments are at the same time wholly or partly shut off from the air supply. Practical experiments have shown that wholly or partly shutting off two opposite compartments at the same time leads to a better turbulence in the inlet zones 34 and hence to a better mixing of the air supplied and the air already present in the space 12.

Practical experiments have further shown that, with a valve member 30 that shuts off two compartments, the mixing of the air supplied and the air already present in the space 12 improves further by setting the rotation of the valve member 30 by the valve actuator 28 in a suitable manner. The setting is then such that during each revolution of the valve member 30 a compartment is in the open and in the closed condition for an equal period of time. Thus, a valve member 30 is formed that can at least partly shut off two compartments at the same time. Other forms of the valve member 30, however, are also possible.

In an embodiment, the housing 14 can be a cylinder-shaped housing 14 having a housing axis BH, which is colhnear with the central axis H. The partitions 22 can then bound circular segment-shaped compartments and also define the valve chamber 36. Two examples of such a housing are shown in the Figures la and lb and Figures 2a and 2b.

In an embodiment, the housing 14 may be block-shaped and may comprise four sidewalls 16c, 16d, 16e, 16f. From each angular point of two sidewalls 16c, 16d, 16e, 16f, a partition 22 as mentioned can extend in the direction of the central axis H, while ending at some distance from this central axis H. The partitions 22 can bound four, substantially triangular compartments, of which a centrally located angle is truncated to form the valve chamber 36. A first example of such a housing is shown in Figures 3a and 3b. A second example is shown in Figure 4. Clearly visible are the truncated angles which form the valve chamber 36, in which the valve assembly 26 with the valve member 30 is disposed.

In an embodiment, the second end wall 16b can be a perforated plate which is provided with perforation openings 40. The perforation openings 40 form at least a part of the air inlet openings 32 of the air inlet zones 34.

By implementing the second end wall 16b as a perforated plate, a greater inflow surface of the compartment can be obtained without the size of the housing 14 needing to be augmented. As a result, a more efficient supply of air to the space 12 is realized. In addition, this configuration also makes it possible to mount the apparatus to a sidewall of the space 12, whereby the air stream that is supplied via the perforation openings 40 out of the second end wall 16b into the space 12 is directed substantially horizontally. An example of this embodiment, where the second end wall 16b faces down, is shown in Figures 2 a and 2b.

In an embodiment, at least a part of the air inlet openings 32 may be provided in the at least one side wall 16c, 16d, 16e, 16f.

By providing the air inlet openings 32 in the sidewall 16c, 16d, 16e,

16f, the air can be supplied to the space 12 in multiple directions at the same time, so that a better mixing with the air present in the space 12 is achieved. Two examples of this embodiment are shown in Figures la and lb and Figures 3 a and 3b.

It is particularly advantageous to combine this embodiment with the earher-mentioned embodiment whereby the second end wall 16b is implemented as a perforated plate, because this brings about that air is supplied to the space 12 in virtually all directions. As a result, a large extent of mixing of the newly supplied air and air already present in the space 12 is achieved.

In an embodiment the apparatus may be provided with an air supply plenum 42 which is connected by an air supply plenum outlet 44 to the air intake opening 20.

Two examples of an air supply plenum 42 with air supply plenum outlet 44 are shown in Figure la and Figure 3a. Clearly visible in Figures la and 3a is that the air supply plenum 42 is connected to the air intake opening 20 which terminates in the valve chamber 36. Also visible in this example is that the valve actuator 28 is arranged in the air supply plenum 42, so that a more compact apparatus 10 is realized and space is saved.

In use of the apparatus 10, an air pressure in the air supply plenum 42 will be higher than an air pressure in the valve chamber 36 and the air inlet assemblies 24 connected therewith.

The pressure variation in the air inlet assemblies 24 resulting from the opening and closing of the valve opening 38 between the air intake opening 20 and the air inlet assemblies 24 will be more pregnant when in the air supply plenum 42 a clearly higher pressure prevails than in the space 12 into which the air is to be blown. Greater pressure variations lead to greater flow rate variations of the air let into the space 12 via the air inlet openings 32 and hence to a greater turbulence in the air inlet zone 34. The greater turbulence results in a better mixing of the air supplied and the air already present in the space 12.

In an embodiment, the valve actuator 28 can adjust the valve member 30 with such a speed and/or frequency that the supply of air to each air inlet assembly 24 is interrupted 1 to 10 times per minute and is preferably interrupted 1 to 6 times per minute.

The frequency and/or speed with which the valve member 30 is adjusted has a direct influence on the formation of turbulence in the air that is supplied via the air inlet openings 32 to the air inlet zones 34 in the space 12. The interruption frequency of the supply of air to an air inlet assembly 24 contributes to a maximization of the formation of whirls in the air inlet zones 34. As a result, in a relatively fast and efficient manner, a

homogeneous mixing of the air supplied and the air present in the space 12 is achieved.

In an embodiment, the valve actuator 28 may be configured for rotating the valve member 30 intermittently. The valve member 30 may, during standstill, substantially completely shut off at least one of the at least two valve openings 38 and the air inlet assembly 24 associated with that at least one valve opening.

In an embodiment, the valve actuator 28 may be configured for rotating the valve member 30 continuously.

In an embodiment, the apparatus 10 can have an air flow rate of at least 5,000 m ³ /hour. This embodiment is especially suitable for buildings or spaces of larger contents, such as theaters, office building spaces or industrial spaces. The apparatus may additionally be configured for considerably smaller air flow rates, such as flow rates of less than 10 m ³ /hour or less than 1 m ³ /hour. Such variants are especially suitable for use in relatively small spaces, such as cars, trucks, or buses, but also residences or small

(commercial) spaces.

In an embodiment, in an air inlet assembly 24 concerned, there prevails a minimum pressure when the valve member 30 is in a position in which the valve opening 38 between the air intake opening 20 and the respective air inlet assembly 24 is at least partly and preferably wholly shut off. In the respective air inlet assembly 24 prevails a maximum pressure when the valve member 30 is in a position in which the valve opening 38 is not shut off. The configuration and the dimensioning of the valve member 30 and the air inlet assembly 24 may be such that the minimum pressure in a respective air inlet assembly 24 is at most 80% of the maximum pressure in the respective air inlet assembly 24. More preferably, the dimensioning and configuration of the valve member 30 and the air inlet assemblies 24 may be such that the minimum pressure is at most 50% of the maximum pressure in the respective air inlet assembly 24.

Thus, a clear variation in flow rates in the different inlet zones 34 is realized, which favorably influences the mixing of the air supplied and the air already present in the space 12.

In an embodiment, of which an example is shown in Figures 9A-9D, the air inlet openings 32 may be provided in walls 16b, 16c of the housing 14 and each be directed to a different part of the space in which the apparatus 10 is set up. In each air inlet opening 32 a valve assembly as mentioned may then be disposed that is implemented as a shutter valve assembly which is provided with a plurality of adjustable shutters 50. Each shutter valve assembly is provided with a transmission 56 for simultaneously adjusting the shutters 50 of the shutter valve assembly, such that the shutters 50 of a shutter valve assembly extend parallel to each other in each case. The transmissions 56 of the at least two shutter valve assemblies are then each drivably connected to the valve actuator. Thus, with a single valve actuator, all shutter valve assemblies can be adjusted simultaneously. The shutters 50 of at least one of the shutter valve assemblies will then be at least in a partly closed position while the shutters 50 of another valve assembly will at the same time be in a somewhat more opened position. Thus, air is let into the space 12 alternately via a different air inlet zone 34.

In further elaboration of this embodiment, of which an example is given in Figures 9A-9D, the valve actuator can comprise an electric motor 58 and a central drive gear 54.

The transmission of each shutter valve assembly can then comprise a series of gears 56 which are in mutual engagement. To that end, with each shutter 50, a gear 56 is connected. Of each shutter valve assembly, one of the gears 56 is in mesh with the central drive gear 54, such that by rotation of the central drive gear 54 all shutters 50 of the apparatus are adjusted simultaneously.

The various embodiments described above can be applied independently of each other and be combined with each other in different ways. The reference numerals in the detailed description and the claims do not limit the description of the embodiments and the claims, and are for clarification only.

KEY TO SYMBOLS

10- apparatus

12- space

14- housing

16a - first end wall

16b - second end wall

16c - sidewall

16d - sidewall

16e - sidewall

16f- - sidewall

18a - air channel

18b - air inlet unit

20- air intake opening

22- partition

24- air inlet assembly

26- valve assembly

28- valve actuator

30- valve member

32 air inlet opening

34- inlet zone

36- valve chamber

38- valve opening

40- perforation openings

42- air supply plenum

44- air supply plenum outlet

H - central axis

HB - housing axis

D - thickness valve member