EP2933575B1 - Diffusion device with lobe inserts and fan coil comprising such a device - Google Patents

Description

The invention relates to an air diffusion device having lobed inserts and a fan coil comprising such a device.

In the field of ventilation, it is known to equip the buildings of ceiling or wall mounted fan coil units to condition and possibly renew the ambient air. The fan coils are distributed throughout the building and each include at least one diffusion device, such as a grill, which distributes conditioned air in the building rooms. These grilles are in practice fixed in the upper part of the walls.

Room air is drawn in and treated in the fan coil before being ejected into the room. So depending on the needs, heating or cooling, the air is either heated or cooled by the fan coil. In addition to the air sucked into the room, the fan coil can also receive fresh air, drawn directly outside or brought by an auxiliary ventilation system. In this case, the outside air is conditioned in the fan coil with air in the room. In cooling mode, the air blown by the fan coil is cooler than the air in the room. It tends to drop to the ground especially as the difference of its temperature with the ambient temperature is important.

It is therefore important to minimize this temperature difference to avoid cold drafts harmful to the comfort of people.

The publication Ilinca Nastase, Amina Meslem, Jordache Vlad and lolanda Colda, Lobed grilles for high mixing ventilation, published in the journal Building and Environment (46 (2011) 547-555), ELSEVIER edition , discloses a diffusion grid comprising lobed vanes, which delimit a thin and wavy trailing edge and promote the mixing of the blown air with the ambient air. However, the jet of air blown through the grid does not benefit from the Coanda effect which tends to press the air jet against the ceiling and increases the range of the jet. Indeed, the jet of air diffused by the grid is not directed towards the ceiling. Thus, this jet has a short range and falls quickly to the ground because of the temperature difference with the ambient air. Users of the room therefore feel a cold draft.

Otherwise, US-B-6,004,204 discloses an air blast nozzle designed to promote this induction phenomenon. This nozzle is housed in a mixing chamber of an air conditioning unit and optimizes the mixing between a fresh air stream or treated, and a stale air flow extracted from the room. Several blowing nozzles may be distributed in the width direction of the mixing chamber or a single elongated blow nozzle may be used. This or these nozzles have the particularity of having a trailing edge having a circumference with curves, that is to say having rounded portions. In this document, the lobes are arranged in a circle or rectangle.

US-A-2,962,952 also discloses an air conditioning unit. This unit comprises a housing defining an upper chamber in which the ambient air is sucked and a lower chamber supplied with fresh air. The fresh air is blown into the upper chamber through a longitudinal slot formed by two corrugated lips. The fan coils with a mixing chamber are not suitable for rooms with a large volume since they do not allow to debit an air "Mixed" enough to package the room. In addition, the fact of providing a mixing chamber in the fan coil reduces the compactness of the apparatus.

Finally, DE-A-1,579,906 discloses an air conditioning device comprising a radiant panel in the form of a corrugated sheet metal plate and two baffles disposed on either side of the plate. The device comprises a plurality of nozzles arranged to distribute air in ducts defined between the radiant panel and a first deflector. Part of the air is then discharged at the longitudinal end of the panel in conduits defined between the panel and the second deflector. The radiant panel allows a particular flow of air within the device, but is not configured to separate an air gap to form a particular external flow promoting mixing with the ambient air.

It is these drawbacks that the invention intends to remedy more particularly by providing a diffusion device comprising one or more lobed inserts, which promotes induction, that is to say the mixing of the jet diffused with the air ambient, without the jet losing its reach.

To this end, the invention relates to a diffusion grid of an air jet as defined in claim 1.

Advantageous, but not mandatory, aspects of the grid are defined in claims 2 to 4.

The invention also relates to a ceiling fan coil as defined in claim 5.

Advantageous, but not mandatory, aspects of the fan coil are defined in claims 6 to 12.

Thanks to the invention, the air flow expelled by the device is separated by the lobes of the insert and the contact surface between the blast air jet and the ambient air is multiplied. Thus, the exchange surface between the blown jet and the ambient air is greater than for a blown air jet block. In addition, the shearing of the primary fluid by the corrugated trailing edge generates additional longitudinal vortices. These two phenomena increase the mixing of the blown air with the ambient air. This mixture makes it possible to homogenise the temperature of the jet relative to that of the ambient air and the users do not feel the sensation of a flow of cold or hot air. In addition, the baffles direct the jet of air in the predetermined direction, which allows to spread the jet along a wall and enjoy the Coanda effect. The air jet therefore retains a satisfactory range, which prevents the air "falling" too quickly towards users.

• la figure 1 est une vue partielle en perspective d'un dispositif de diffusion comportant plusieurs ailettes, entre lesquelles sont disposés des inserts,
• la figure 2 est une vue en perspective et à plus grande échelle d'un insert de la grille de la figure 1,
• la figure 3 est une vue selon la flèche III à la figure 2,
• la figure 4 est une vue selon la flèche IV à la figure 3,
• la figure 5 est une coupe partielle selon le plan V à la figure 1,
• la figure 6 est une vue partielle en perspective d'un ventilo-convecteur plafonnier, comportant un dispositif de diffusion selon un deuxième mode de réalisation de l'invention,
• la figure 7 est une vue à plus grande échelle de l'encerclé VII de la figure 6,
• la figure 8 est une coupe selon le plan VIII de la figure 7, dans laquelle le ventilo-convecteur est schématiquement représenté en configuration installée dans un faux-plafond,
• la figure 9 est une vue analogue à la figure 3 représentant une variante de réalisation d'un insert, adapté pour être fixé dans le ventilo-convecteur de la figure 6,
• la figure 10 est une vue en élévation par rapport à la figure 9.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the description which follows, of two embodiments of a broadcasting device according to its principle, given solely as a example and with reference to the drawings in which:

• the figure 1 is a partial perspective view of a diffusion device comprising a plurality of fins, between which are arranged inserts,
• the figure 2 is a perspective view and on a larger scale of an insert of the grid of the figure 1 ,
• the figure 3 is a view according to arrow III at figure 2 ,
• the figure 4 is a view along arrow IV at the figure 3 ,
• the figure 5 is a partial section along plane V at the figure 1 ,
• the figure 6 is a partial perspective view of a ceiling fan coil, comprising a diffusion device according to a second embodiment of the invention,
• the figure 7 is a larger-scale view of circled VII from the figure 6 ,
• the figure 8 is a section according to plan VIII of the figure 7 , in which the fan coil is schematically shown in configuration installed in a false ceiling,
• the figure 9 is a view similar to the figure 3 representing an alternative embodiment of an insert, adapted to be fixed in the fan coil of the figure 6 ,
• the figure 10 is an elevation view from the figure 9 .

On the figure 1 is shown a diffusion device 1, which is a grid. To the figure 1 , the grid 1 is shown from the inside of the room. In practice, grid 1 is adapted to be installed in the upper part of a wall, that is to say near the ceiling. This grid 1 is intended to blow the treated air in a room of a building, that is to say it is a simple flow grid. The grid 1 can be mounted on a fan coil housed in a wall or directly at the end of a duct connected upstream to a fan coil. In the latter case, the grid 1 is a static transmitter and the associated fan coil upstream can diffuse air through several transmitters distributed in the building.

In this document, the "up", "down", "top" and "bottom" directions must be interpreted in relation to an installed grid 1 configuration in the wall.

The ventilation grid 1 comprises a rectangular frame 2, which is partially shown in FIG. figure 1 and a series of fins 8, which are arranged horizontally in the frame 2 one above the other. The fins 8 are deflectors which direct the air blown through the ventilation grille 1 in a predetermined direction Δ, which is turned towards the ceiling. Indeed, as visible at the figure 1 the fins 8 have a bent shape, with a horizontal upstream portion 8a and a downstream portion 8b directed in the direction Δ, that is to say upwards. Thus, the air blown through the ventilation grid 1 is directed towards the ceiling of the room and takes advantage of the effect "Coanda", which improves the range of the jet.

Inserts 10 are arranged between each pair of two adjacent fins 8. The fins 8 thus define between them O10 orifices for passage of the jet of air around the inserts 10. On the figure 1 the inserts 10, the frame 2 and the fins 8 are partially shown in length for clarity of the drawing. The inserts 10 are attached to two vertical posts 4 and 6 of the frame 2. The inserts 10 have the function of increasing the induction of the air jets passing between the fins 8 of the grid 1. The inserts 10 are arranged slightly in upstream relative to the fins 8 in the flow path of air blown through the grid 1, so that the air blown through the grid 1 is generally directed towards the ceiling and takes advantage of the Coanda effect.

On the figure 2 is shown in more detail an insert 10. In the following description only an insert 10 is described since the inserts 10 are all identical.

The insert 10 extends along a longitudinal axis X10, which is a horizontal direction when the insert is mounted in the ventilation grille 1. The insert 10 comprises two hooks 100 and 102 for attachment to the bars 4 and 6 of the the gate 1. The insert 10 comprises lobes 108 and 110 which are arranged alternately one after the other along the axis X10, that is to say that the lobes 108 and 110 are arranged in line right, or on a segment. The lobes 108 and 110 are rounded portions of the insert 10 which are respectively disposed above and below a median plane P10 of the insert 10. The lobes 108 and 110 each have a concavity turned towards the median plane P10 .

The lobes 108 and 110 define a regular and undulating serration along the axis X10. They delimit a trailing edge 106 which is a thin, undulating edge. We are talking about a "lobed" edge. The ripples of the trailing edge 106 are identical and the trailing edge 106 has a thickness e106 constant over the entire length of the insert 10. The thickness e106 is of the order of 1 mm, while the length of the insert 10, which depends on the dimensions of the grid 1, is between 40 and 100 cm. The trailing edge 106 includes rounded portions 106a and 106b which are respectively disposed above and below the median plane P10. The rounded portions 106a and 106b have an identical radius of curvature and extend over approximately 180 °. The radius of curvature of the portions 106a and 106b is between 1 mm and 10 mm, in particular of the order of 2 mm. The portions 106a and 106b are connected successively to one another by rectilinear portions 106c, which are perpendicular to the median plane P10 and substantially vertical in the installed configuration of the insert 10 in the grid 1.

The insert 10 also comprises a leading edge 104, which is rectilinear and extends parallel to the longitudinal axis X10.

The plane P10 is a generally horizontal plane in the installed configuration of the grid 1 in the wall. This plane P10 passes through the leading edge 104 and the middle of the rectilinear portions 106c.

In operation, the air is routed from a ventilation unit to grid 1. On the figure 2 , the flow of air from the ventilation unit and opening into the grid 1 is symbolized by two arrows F1. In practice, the air blown through the grid 1 is cooled or preheated according to the type of packaging selected, that is to say, air conditioning or heating. The air blown through the grid 1 has a large temperature difference with respect to the ambient air. The lobes 108 and 110 each delimit a passage channel of the air flow. Thus, the flow of air F1 entering the grid 1 is divided, or separated, by the lobes 108 and 110 of the insert 10.

F2 and F3 respectively designate the flow of air flow along the inner wall of the lobes 108 and 110. Here, the "inner" side of the lobes 106 and 108 is defined as the side facing the median plane P10. The air flow F2 in the channels of the lobes 108 are directed upwards while the airflow F3 flows in the channels of the lobes 110 are directed downwards, which allows to separate in two the jet of air ejected through the grid 1. By dividing the flow of air blown by the grid 1, the The contact surface between the blast air jet and the ambient air is reduced and the healthy air mixes more easily with the ambient air. The inserts 10 thus improve the induction of the jet blown through the grid 1, which reduces the temperature difference between the jet blown and the ambient air by about 20%.

The jet of air blown through the grid is slowed down by induction because of interactions with the surrounding air, which is why the geometry of the insert 10 actually promotes induction over a short distance, between 5 and 10 cm at the outlet of the grid 1. Thus, the speed of the jet is only slightly impacted and the jet retains a satisfactory range. On average, a range of 4 to 5 m is satisfactory since it generally allows to reach an opposite wall of a room in which is installed the grid 1. In this way, in air conditioning mode, the air does not "fall" not too fast in the direction of the ground with too cold a temperature.

This range is even more important to achieve in the case where the air is heated. Indeed, in this case, it is necessary to generate a circulatory movement of the hot air within the room to prevent stratification of the air layers and the formation of a "hot" sheet near the ceiling. Such a sheet would indeed cause the ceiling to warm up and, by radiation, a feeling of "hot" undesirable for users.

Moreover, this type of insert can also be integrated into a ceiling fan coil 3, shown in FIGS. figures 6 and 8 which is adapted to be housed in a false ceiling 5 of a room. This type of apparatus is commonly referred to as a "diffusion cassette" and has a diffusion slot 30 through which air is blown in a horizontal plane near the ceiling. This diffusion slot is delimited between a plate 322 of a parallelepiped box and a diffuser 34. The diffuser panel 34 is disposed below the box 32. The diffuser panel 34 and the plate 322 are deflectors which guide the air jet blown by the fan coil 3 in a predetermined direction Δ. The direction Δ is a horizontal direction so that the air diffused by the fan coil 3 "licks" the ceiling.

The slot 30 forms a passage opening of the air jet around several inserts 10. The inserts 10 extend along each side of the slot 30. The inserts 10, the diffuser panel 34 and the plate 322 thus form together a diffusion device 1 of the fan coil 3.

Some "four-way" cassettes broadcast air in four coplanar directions in pairs. In this case, the diffusion slot 30 is a rectangular peripheral slot. Other cassettes, called "three-way", do not air only in three coplanar directions and the slot extends only on three sides of the box. In this case, the diffusion slot 30 is U-shaped. figure 6 , F4 and F5 designate two directions of diffusion of an air jet.

The inserts 10 are fixed on the upper surface of the panel 34. They comprise fixing lugs 101, which are screwed to the panel 34. The inserts 10 may comprise fastening means for securing them to one another. It is also possible to make a monobloc insert having a U-shaped or rectangular shape depending on the type of cassette used.

Alternatively, the grid 1 can be mounted on the ceiling.

On the Figures 9 and 10 is shown an alternative construction of an insert 10 '. This insert 10 'is intended to be integrated in a ceiling fan coil as described above. It is partially represented in length on Figures 9 and 10 . It comprises three tabs 101 for fixing to the panel 34 and delimits inclined lobes 110 '. Indeed, unlike lobes 110 of the insert of Figures 1 to 8 , which extend perpendicularly to the longitudinal axis X10 of the insert 10, the lobes 110 'form with an axis Y10 normal to the axis X10 an angle A110 of between -60 ° and + 60 °, in the example equal to 20 °. This angle is measured between the axis Y10 and a direction D110 along which the lobes 110 'extend. The inserts 10 are then able to orient the air jets diffused on the three or on the four sides of the cassette in a mean direction inclined with respect to the directions F4 and F5 which are perpendicular to the sides of the diffuser panel 34. The average direction air jets diffused on the sides of the cassette is thus oriented by the inserts 10 in the diffusion plane of the fan coil 3, which is a horizontal plane. This makes it possible to avoid frontal interaction of the air jets emitted by two cassettes disposed opposite each other and consequently the formation of a cold or hot current resulting from this interaction. The users of the room are therefore not hampered by drafts of cold or hot air directed towards the ground. The insert 10 'also comprises two edges 114 bevelled, that is to say cut at 45 ° with respect to the axis X10 or Y10. This allows four inserts 10 'end to end to form a rectangular frame. In a variant not shown, the ceiling fan coil 3 comprises means for orienting the inserts 10 in a horizontal plane. For example, these means may comprise a movable support serving as a pivot for orienting the inserts 10 over a range of angles ranging from -60 ° to + 60 ° with respect to an axis normal to one side of the panel 34.

Claims (12)

1. Diffusion grille (1) for a jet of air, comprising: at least one insert which comprises lobes (108, 110; 110') for separating into two differently oriented streams (F2, F3) an air stream (F1) ejected through the grille, the lobes delimiting a thin and undulating trailing edge (106), characterised in that it further comprises two fins (8; 34, 322) arranged on either side of the insert (10; 10'), which fins define between them an orifice (O10; 30) for passage of the jet of air around the insert and which guide the jet of air in a predetermined direction (Δ).
2. Grille according to claim 1, characterised in that each insert (10) is arranged upstream relative to the fins (8) on the flow path of the jet of air diffused by the grille.
3. Grille according to claim 1 or 2, characterised in that the fins (8) are bent and comprise a downstream portion (8b) which extends in the predetermined direction (Δ).
4. Grille according to any one of the preceding claims, characterised in that the inserts (10) comprise means (100, 102) of attachment to two rods (4, 6) of the grille (1).
5. Ceiling-mounted fan coil unit, comprising at least one insert which comprises lobes (108, 110; 110') for separating into two differently oriented streams (F2, F3) an air stream ejected between a diffuser panel (34) and a plate (322) of the fan coil unit, the lobes delimiting a thin and undulating trailing edge (106), the diffuser panel and the plate being arranged on either side of the insert (10; 10'), the diffuser panel (34) and the plate defining between them an orifice (30) for passage of the jet of air and guiding the jet of air in a predetermined direction (Δ).
6. Fan coil unit according to claim 5, characterised in that it comprises a plurality of inserts (10) and means for orienting the inserts (10) in a horizontal diffusion plane of the fan coil unit.
7. Fan coil unit according to claim 6, characterised in that an angle of orientation of the inserts in the horizontal plane is between -60 and +60° relative to an axis normal to a side of the diffuser panel (34).
8. Fan coil unit according to claim 6 or 7, characterised in that the angle of orientation of the inserts in the horizontal plane is adjustable by means of a movable support.
9. Fan coil unit according to any one of claims 5 to 8, characterised in that the diffuser panel (34) and the plate (322) are arranged to diffuse the jet of air in three or four predetermined directions (F4, F5) which are coplanar.
10. Fan coil unit according to any one of claims 5 to 9, characterised in that each insert (10) comprises means of fixing to the diffuser panel (34).
11. Fan coil unit according to claim 10, characterised in that the means of fixing to the diffuser panel (34) are fixing lugs (101) adapted to be screwed to the panel (34).
12. Fan coil unit according to any one of claims 5 to 11, characterised in that the lobes (110') of the insert (10') each extend in a direction (D110) which is inclined relative to an axis (Y10) normal to a longitudinal axis (X10) of the insert.

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