EP2405211B1

EP2405211B1 - Diffuser for an air conditioning plant

Info

Publication number: EP2405211B1
Application number: EP20100425230
Authority: EP
Inventors: Andrea Cighetti
Original assignee: FCR SpA
Current assignee: FCR SpA
Priority date: 2010-07-08
Filing date: 2010-07-08
Publication date: 2014-12-31
Anticipated expiration: 2030-07-08
Also published as: EP2405211A1

Description

Field of the invention

The invention lies in the field of the devices for spreading conditioned air from a room ceiling, which devices belong to the kind of the mixing systems.

Prior art

The problem of making the air spread variable in its direction depending on whether the conditioning plant is working for summer or winter conditions has been solved by the state of the art in different ways. The environmental comfort and the ventilation efficiency depend on said direction variation; in particular, in case of summer air conditioning, since the cold air spread from a ceiling tends to "precipitate", it is convenient to impart the air spread from the device slits an adhesion to the room ceiling as lasting as possible, whilst in case of winter conditioning, since the hot air tends to "float", it is convenient to drive down the spread air. These techniques in general apply to the devices for spreading air from a room ceiling.
While "divergent discharge" will be referred to an air that spreads from the slits with a radial component moving apart from the center of the diffuser, "convergent discharge" will be referred to an air that spreads from the slits with a radial component approaching the center of the diffuser, i.e. having a centripetal component (see Fig. 3).
Hence, by "discharge angle" it will be intended the angle the air jets form with respect to the ceiling of the room in which the diffuser is installed (see Fig.5).
Conventionally the diffuser comprises two main elements: the plate and the deflection flaps. The plate is generally square and is provided with a plurality of slits for the air ejection, the slits being set in non radial position (as it may be realized from Fig.8). Each flap is placed into the diffuser in correspondence with a slit, a similar diffuser for an air conditioning plant is known from EP 1 767 877 . In the case of ceiling swirling diffusers equipped with a plurality of slits and deflection flaps, two alternatives are known: a) the discharge angle of the air jets is continuously variable within a defined range, always with divergent discharge; b) the air discharge may be divergent or convergent, but the discharge angle is the same in both conditions.

Drawbacks of the prior art

The drawbacks of the prior art substantially reside in the manufacturing complication and consequently in the high cost of the devices as far as case a) is concerned and, in the case b), in the limited performances of the devices due to the same air discharge angle which is suitable to one only of the two possible working modes, summer or winter conditioning.

Invention general disclosure

This present invention stems from an idea for solving the problem cited above, i.e. making the air direction variable depending on the plant working conditions and is an evolution of said case b). The invented solution makes it possible to impart the air jets two different discharge angles: a first angle for the divergent discharge with flaps tilted in a first direction and a second angle for the converged discharge with flaps tilted in a second direction substantially opposite, but not equal, to the first one. In particular, both first and second discharge angles may be defined by geometry in the design phase or as a consequence of successive adjustments in order to get the maximum effect from the invention. The means suitable to realize such a solution is a plurality of air deflection flaps, conventionally positioned into a diffuser in correspondence with the air outlet slits set in non-radial position, each flap being provided with means for rotating about a longitudinal non-central axis.
The technique for spreading air from a room ceiling teaches that, under standard velocity and thermic gap conditions, if an air jet is discharged into a room with an angle < 30°, that jet spontaneously will adhere to the ceiling (Coanda effect) and will spread from the diffuser towards the room side walls along the room ceiling, whilst if the jet discharge angle is > 40°, that jet will not adhere to the room ceiling and will spread from the diffuser towards the room bottom. Since the scope of this invention is getting adhesion of the air jet to the room ceiling under divergent discharge (cooling condition) and not getting adhesion to the room ceiling under convergent discharge (heating condition), the inventor conceived a flap suitable to rotate about one of its longitudinal non-central axis: in this way, two different inclinations are available for the flap so that the air jet going out of a slit can be alternatively directed to form an angle a < 30° or β > 40°. So, with a flap plurality conveniently positioned in correspondence of their non-radial slits in the plate, a divergent discharge adhering to the room ceiling or a convergent discharge not adhering to the room ceiling are caused.
A number of trials made it possible to optimize the angle position of the flap with respect to the plate inner wall as a = 24° and β = 42°.
It will be realized that an installer or a user will select the two discharge angles, each in a neighborhood of one of the above angle values, on the basis of the results of jet spread trials and of the dimensions of the diffuser slits.

Advantages of the invention

The invention supplies in a simple way a diffuser capable of working in each of the above two conditions, divergent or convergent discharge.

Detailed description of the invention

The invention will be now illustrated in detail by an example and the help of drawings where:

Fig. 1 is a first view of a diffuser plate from bottom,
Fig. 2 is a second view of a diffuser plate from bottom,
Fig. 3 is a first perspective view of a flap so positioned that direction A1 of the discharged air is convergent,
Fig. 4 is a second perspective view of a flap so positioned that the direction A2 of the discharged air is divergent,
Fig.5 is a side view of a flap in the two positions a user can set it with respect to the slit below,
Fig. 6 shows a photograph of smokes diffusion trial from a square diffuser bearing flaps in divergent position,
Fig. 7 shows a photograph of smokes diffusion trial from a square diffuser bearing flaps in convergent position and
Fig. 8 comprises two diagrammatic views, (8a) is relevant to the flap position capable of discharging air in a divergent direction and (8b) is relevant to the flap position capable of discharging air in a convergent direction.

Fig. 1 shows the plate 3 of a diffuser 1 provided with eight rectangular slits 2 in their non-radial setting.
Fig. 2 shows the plate 3 of a diffuser 1a provided with a peripheral plurality of slits 2 and an inner plurality of slits 2a, all of them set in non-radial position.
Fig. 3 shows a flap 4 tilted with a discharge angle α = 42°, in that a position the direction A1 of the discharged air is convergent and has a centripetal component; flap 4 bears two opposite pins 7 aligned with the longitudinal non-central axis X-X and rotatable into two respective forks 6 each fixed to a base 5 in turn fixed along the edge of the short side of slit 2.
Fig. 4 shows a flap 4 tilted with a discharge angle β = 24°, in that a position the direction A2 of the discharged air is divergent and has a centrifugal component;
again flap 4 bears two opposite pins 7 aligned with the longitudinal non-central axis X-X and rotatable into two respective forks 6 each fixed to a base 5 in turn fixed along the edge of the short side of slit 2.
Fig. 5 shows the two positions flap 4 takes once the inclination given it is a = 42° so as to get a convergent air discharge and is β = 24° so as to get a divergent air discharge; the figure also shows the distances of the rotation axis X-X with respect to a slit 20 mm wide (short side), to the slit medium point M and to the inner wall of plate 3.
Fig. 6 shows a square diffuser 3 in a working trial with divergent discharge A2: the smokes make visible the air jets adhering to the ceiling.
Fig. 7 shows the same square diffuser from figure 6 in a working trial with convergent discharge A1: the smokes make visible the air jets not adhering to the ceiling.
Fig. 8 shows the components of the air discharge direction in the case (8a) of divergent discharge and in the case (8b) of convergent discharge. Reference letter F shows the frame of a plate 3 of a square diffuser having its center in C and comprising a plurality of non radial slits, not shown. Of the plurality of flaps associated with the plurality of slits only a flap 4 is shown for simplicity. In the figure 8 a flap 4 is tilted with an angle β = 24° to cause a divergent air jet with discharge direction Dc and centrifugal component Cf. In the figure 8 b flap 4 is tilted with an angle α = 42° to cause a convergent air jet with discharge direction Dc and centripetal component Cp.

Claims

Diffuser (1) for an air conditioning plant wherein each of the deflection flaps (4) for the conditioned air jets is positioned over a corresponding non-radial slit (2) in the diffuser plate (3) for taking such a discharge angle of the air jets that vary between two opposite positions, characterized in that the deflection flap (4) is provided with means (7) that makes the flap (4) rotate about a longitudinal non-central axis (X-X) thereof in order to direct the flap (4) in one or the other of the two opposite positions where it takes two corresponding discharge angles, a first angle (α) for causing a convergent discharge (A1) and a second angle (β) for causing a divergent discharge (A2).
Diffuser according to claim 1 characterized in that the first discharge angle (α) is comprised in a neighborhood of 42° and the second discharge angle (β) is comprised in a neighborhood of 24° so as to respectively cause the convergent discharge (A1) and the divergent discharge (A2).
Diffuser according to claims 1 and 2 characterized in that the longitudinal non-central axis (X-X) of flap (4) is at a distance of about 6,00 mm from the inner wall of the diffuser plate (3) and of about 3,4 mm from the medium point (M) of flap (4) small side in a diffuser provided with slits of about 20 mm short side.