EP0122188B1 - Device for the simultaneous control of the air flow and the velocity for an air conditioning plant with variable air flow - Google Patents

Description

In the field of air conditioning, the diffusion of air conditioning in the rooms of a room is a major problem for obtaining the comfort perceived by users.

Variable air flow systems accentuate technical problems such as falling cold air, the interactions of diffusers with each other, variations in pressure in distribution ducts, etc.

To meet these problems, devices such as those defined, for example, in French patents FR-A-2 091 004, FR-A-2 188 113, FR-A-2 222 920, FR- are currently known. A-2 259 323, FR-A-2 317 700, FR-A-2 323 185, FR-A-2451 550.

• fonctionnement à pression d'air relativement forte engendrant un niveau sonore perceptible,
• absence de contrôle du débit d'air,'qui doit être effectué par ailleurs,
• nécessité d'obtenir des pressions similaires de faible valeur en amont de chaque diffuseur, ce qui nécessite un surdimensionnement des gaines de distribution,
• absence de contrôle de la diffusion d'air interdisant des variations de débit d'air dans les proportions souhaitées,
• complication des systèmes entraînant un prix élevé.

The corresponding materials currently on the market have drawbacks such as:

• operation at relatively high air pressure generating a perceptible sound level,
• lack of air flow control, 'which must be carried out elsewhere,
• need to obtain similar pressures of low value upstream of each diffuser, which requires oversizing of the distribution ducts,
• absence of air diffusion control preventing variations in air flow in the desired proportions,
• complication of systems resulting in a high price.

The present invention aims to avoid these drawbacks by defining a simple system that can operate at low pressure, allowing variations in air flow in significant proportions and operating without the pressure variations that can occur on the distribution network of the air conditioning does not disturb the characteristics of the air jet at any point of diffusion.

In the device which is the subject of the invention and which is designed to obtain this result, a flap, disposed immediately upstream of the air diffusion point, is subjected to a restoring force generated by a spring or a counterweight so that the shutter obstructs the air blowing section, while the air circulated tends to open the blowing section to a position where the shutter meets a feeler which reacts on a motorized damper located upstream of the shutter. The flow rate, the blowing speed and the diffusion section are then constant and independent of the air pressure prevailing upstream of the air register. The displacement of the probe makes it possible to vary the useful blowing section and therefore the air flow rate, while maintaining a sufficient blowing speed to ensure good diffusion of air in the treated space.

The speed control and the air flow control are thus carried out by the same device.

The description below, which refers to the drawing given by way of example, will make it possible to understand clearly how the invention can be implemented.

Figure 1 shows a section of the control system in its preferred configuration. Figure 1a shows a detail on a larger scale. Figures 2, 3 and 4 are partial sections of variants.

In FIG. 1, a box 1 made of galvanized sheet metal constitutes an expansion box between the distribution sheath connected at 9 and the wall-type diffuser 2 which may include orientable blades for properly directing the jet of blown air. The connection between the distribution duct and the above-mentioned box is made by means of a circular flexible duct.

The invention relates essentially to the device arranged inside the box, for ensuring the automatic regulation of the air flow and the control of the diffusion.

• un volet 3 constitué par une tôle d'aluminium pliée, articulé sur un couteau 4 et muni d'un contrepoids 5 qui détermine une position de repos du volet telle, que ce dernier obstrue la section de soufflage et telle, que l'air mis en circulation dans le caisson tend à faire pivoter le volet en ouvrant progressivement la section de soufflage vers le diffuseur 2 ; le contrepoids est réglable par adjonction de plaques de tôle 5a simplement posées dans l'un des replis de la tôle mobile 3 ;
• un registre motorisé 6 constitué par deux plaques en tôle articulées entre elles dont l'une 7 est en position fixe et inclinée à proximité de l'orifice d'entrée d'air 9 dans le caisson 1, de telle sorte que la deuxième tôle 8 qui est mobile puisse obstruer ledit orifice 9 d'entrée d'air, quand cette tôle est dans sa position verticale. La motorisation de ce registre est réalisée par un élément gonflable 10 disposé entre les deux plaques de tôle. Dans le but de parfaire l'étanchéité du registre, et de réduire les bruits d'air pouvant apparaître à la fermeture du registre, la plaque mobile 8 peut être revêtue d'un feutre ou d'une feuille de caoutchouc mousse par exemple ;
• un palpeur pneumatique 11, constitué par un système de buse (figure 1a) pouvant être obstruée par une bille 11 a disposée à proximité du volet 3, de telle sorte qu'en s'ouvrant le volet vient en contact avec la bille qui ferme la buse. Ce palpeur est fixé sur une plaque de tôle mobile 12 qui peut se déplacer sous l'effet d'un élément gonflable 13 de telle sorte qu'il puisse prendre une position plus ou moins proche de la position de repos du volet 3. Les deux positions extrêmes du palpeur sont déterminées par deux butées mécaniques 14 et 15 réglables. L'élément gonflable 13 associé au palpeur peut être actionné à partir d'un thermostat d'ambiance 16 sensible à la température du local ou à toute autre grandeur à contrôler ;
• un dispositif 17 de répartition d'air, destiné à uniformiser la vitesse de l'air sur les différents points de la section du diffuseur utilisé et constitué par un déflecteur en tôle disposé perpendiculairement au flux d'air en amont de l'ouverture variable du volet 3.

The device includes:

• a shutter 3 constituted by a folded aluminum sheet, articulated on a knife 4 and provided with a counterweight 5 which determines a rest position of the shutter such that the latter obstructs the blowing section and such that the air put circulating in the box tends to rotate the flap by gradually opening the blowing section towards the diffuser 2; the counterweight is adjustable by adding sheet plates 5a simply placed in one of the folds of the movable sheet 3;
• a motorized damper 6 consisting of two sheet metal plates hinged together, one of which 7 is in a fixed and inclined position near the air inlet orifice 9 in the box 1, so that the second sheet 8 which is movable can obstruct said air inlet orifice 9, when this sheet is in its vertical position. The motorization of this register is achieved by an inflatable element 10 disposed between the two sheet metal plates. In order to improve the sealing of the damper, and to reduce the air noise that may appear when the damper is closed, the movable plate 8 can be covered with a felt or a sheet of foam rubber for example;
• a pneumatic feeler 11, constituted by a nozzle system (FIG. 1a) which can be obstructed by a ball 11 a disposed near the flap 3, so that when the flap opens, it comes into contact with the ball which closes the nozzle. This probe is fixed on a movable sheet metal plate 12 which can move under the effect of an inflatable element 13 so that it can assume a position more or less close to the rest position of the flap 3. The two extreme probe positions are determined by two adjustable mechanical stops 14 and 15. The inflatable element 13 associated with the probe can be actuated from a room thermostat 16 sensitive to the temperature of the room or to any other quantity to be controlled;
• an air distribution device 17, intended to standardize the air speed at the different points of the section of the diffuser used and constituted killed by a sheet metal deflector arranged perpendicular to the air flow upstream of the variable opening of the shutter 3.

• Au repos, avant la mise en marche du ventilateur de l'installation concernée, le volet 3, sous l'effet de son contrepoids 5, est en position haute et obstrue la section de soufflage. En supposant que l'installation distribue de l'air froid et que la température du local traité est plus élevée que la consigne du thermostat d'ambiance 16, ce dernier détermine une pression nulle sur un circuit pneumatique raccordé sur l'élément gonflable 13 du palpeur 11 et en conséquence, ce dernier, sous l'effet du poids de la tôle qui le supporte, est en position basse.

The operation of this device can be explained as follows:

• At rest, before starting the ventilator of the installation concerned, the shutter 3, under the effect of its counterweight 5, is in the high position and obstructs the blowing section. Assuming that the installation distributes cold air and that the temperature of the treated room is higher than the setpoint of the room thermostat 16, the latter determines zero pressure on a pneumatic circuit connected to the inflatable element 13 of the probe 11 and consequently, the latter, under the effect of the weight of the sheet which supports it, is in the low position.

As a result of the two preceding circumstances, the feeler 11 is moved away from the shutter 3 and the ball 11 lets the pressure of the pneumatic circuit on which the feeler is connected escape.

This pneumatic circuit, supplied at 16a by a suitable source of pressurized air, comprises a restriction or calibrated orifice 18 downstream of which is a bypass 18a for supplying the probe 11 then a second restriction or calibrated orifice 19 disposed at the inflatable element 10 input from motorized damper 6.

It can be deduced therefrom that the pressure in the inflatable element 10 of the motorized register 6 is zero and that the latter, under the effect of the weight of the movable plate 8, is in the open position.

When the fan of the air conditioning system is turned on, the amount of air introduced into the system is too large because the motorized damper 6 is in full opening. The shutter 3, under the predominant effect of the air pressure exerted on its upstream face, opens until it comes into contact with the feeler 11.

This contact determines the closure of the nozzle by the ball 11a, which causes an increase in pressure between the two restrictions or calibrated orifices 18 and 19 of the air circuit actuating the motorized register 6. This pressure generates, by means of the second restriction 19, a gradual rise in pressure inside the inflatable element 10 of the motorized damper 6, which therefore closes slowly.

This closing movement continues until the air flow is reduced to the value which corresponds to the balance of the flap 3, the latter then releasing the ball 11a from the feeler which generates a reopening cycle of the register 6 and and so on.

The oscillation movements of the shutter 3 corresponding to the above-mentioned operation are damped by the second restriction 19 so that they can be considered negligible in the sense that they are imperceptible at the level of the diffusion air jet. .

The air flow is then maximum and fixed on the one hand by the position of the corresponding stop 15 of the probe 11, which fixes the maximum free cross-section of the diffuser, and on the other hand by the value of the counterweight 5 which fixes the air pressure exerted on the upstream face of the shutter 3 when the latter is balanced, which fixes the blowing speed. Under these conditions, the air flow can be considered to be constant and independent of the pressure upstream of the motorized register 6 since the latter controlled by the probe 11 reacts at all times.

When the temperature of the treated room drops and tends towards the setpoint of the thermostat 16, the latter causes a pressure rise in the pneumatic circuit connected to the inflatable element 13 associated with the probe 11, which causes the displacement of the latter upward. and leads to a new balance in strand 3.

The new position of this flap reduces the free diffusion section, which decreases the flow of blown air. The speed depending on the configuration of the flap and its counterweight can be considered constant in the place of use.

When the room temperature is reached, the position of the probe is fixed by the stop 14 corresponding to the minimum air flow.

When the room temperature tends to rise, the reverse cycle is established to gradually increase the air flow.

It should be noted that for a given position, even an intermediate position, of the probe, the flow rate is not disturbed by the variations in air pressure which may exist in the distribution duct.

It has been said previously that the oscillations of the shutter 3, around the position of contact with the probe, are negligible and do not disturb the stability characteristics of the blowing air jet in the environment treated.

It should be noted, however, that these oscillations can cause a slight noise corresponding to the contact of the flap on the probe. This noise can be easily eliminated by the use of a soft material applied to the flap in the area of contact with the probe.

It should also be noted that the configuration of the flap and its counterweight can be chosen so that the blowing speed, instead of being constant, is a function of the position of the flap in order to improve the characteristics of desired diffusion.

For example at low flow rate, a higher blowing speed can be chosen to maintain an almost constant diffusion range. For this, it suffices that the center of gravity of the mobile equipment constituted by the flap 3 and the counterweight 5 deviates appreciably from the vertical plane passing through the axis of rotation as the flap rises, reducing the air supply section.

As mentioned above, the regulation system can be of the pneumatic type. The most conventional pneumatic control systems use compressed air at a pressure of approximately 1 bar. For the system which is the subject of the invention, and in particular for the configuration described by way of nonlimiting example, it may be chosen, for the supply of 16a, a lower compressed air pressure, preferably less than 0.2 bar, for example of the order of 0.05 bar, which has multiple advantages. In this case, the production of compressed air is silent and inexpensive, which allows it to be used even in the case of small or medium-sized installations.

On the other hand, the configuration of the mechanical parts and the inflatable elements mentioned above is simpler to manufacture.

Most regulation systems include an adjustment member, the position of which is significant from the point of operation in the working area at a given time. However, in most cases, the position of this adjusting member is not proportional to the effect produced on the quantity to be checked.

It may be noted that the regulation system, described in the present description, comprises a moving part 3 which modifies the free section of the air diffuser. This section can be considered proportional to the air flow and therefore to the power developed in the treated enclosure. This makes it possible to view the percentage of work of the installation at a given instant and, on the other hand, to facilitate the adjustment of the minimum and maximum flow without the need to use charts, and without it being need to calibrate during manufacturing.

The device which is the subject of the invention can be adapted to diffusers other than wall type diffusers. For exemple :

Figure 2 shows, in sectional view, the arrangement of the flap 3 which can be associated with a floor grid or a light grid allowing vertical blowing; Figure 3 shows, in sectional view, the arrangement of the flap which can be associated with a ceiling linear diffuser; Figure 4 shows, in sectional view, the arrangement of mobile equipment which allows a distribution of the ceiling type of round, rectangular or square shape.

Claims (11)

1. Device ensuring at each point of air diffusion of an air conditioning installation a circulation of air at a substantially constant speed and at variable flow as a function of a controlled value, using a movable device (3) arranged immediately upstream a diffuser (2) subjected on the one hand to a mechanical return force such that the movable device tends towards the position which progressively obstructs the cross-section of the diffuser (2) and, on the other hand, to the pressure of the air circulating in the system, in such a way that all the forces applied to the movable device (3) fix a balanced position of this latter, characterized in that it includes :

a) a sensor (11) of electrical, electronic or pneumatic type, arranged next to the movable device (3), whose position in the system determines the useful area of the air diffuser, in the sense that the movable device subjected to an increase of circulating air pressure comes into contact with the sensor (11) which reacts on a motorized air damper (6) arranged upstream of the movable device (3) in such a way that this latter oscillates constantly about its position having caused its contact with the sensor,

b) a device (12, 13) enabling the displacement of this sensor (11) from the controlled value, with the objective of causing the useful area of the diffuser to change in such a way that the same movable device (3) performs at the same time the function of pressure detector necessary for the regulation of speed and the function of a variable shut-off device of the circulation area enabling the variation of the air flow.

2. Device as claimed in claim 1, wherein the movable equipment is a bent metal sheet (3) articulated on a blade (4) and includes a counterweight (5) adjustable by addition of sheet metal plates simply placed on one of the bends of the movable sheet (3).

3. Device as claimed in claim 1 or 2 wherein the movable equipment (3) with its counterweight (5) is arranged in such a way that the pressure, and therefore the speed of circulation, is a function of the position of the movable device, and therefore of the useful area of diffusion.

4. Device as claimed in anyone of the previous claims, wherein the sensor (11) of the pneumatic type is constituted by a tube whose extremity includes a ball (11a) which, under the action of the movable device obstructs the tube and causes a rise in pressure in the pneumatic circuit, which operates the closure of the motorized air damper by the intermediary of a servo-motor.

5. Device as claimed in anyone of the previous claims, wherein the motorized air damper (6) consists of a sheet metal plate (8) pivoting about a horizontal axis in such a way that the weight of the sheet serves as a return force, this sheet being displaced under the action of an inflatable component (10) receiving a compressed air pressure.

6. Device as claimed in claim 5, wherein the pneumatic supply circuit of the inflatable component (10) is provided with a calibrated orifice (19) having the objective of damping the oscillations of the movable device.

7. Device as claimed in anyone of the previous claims, wherein the device enabling the displacement of the sensor (11) is constituted by a sheet metal plate (12) pivoting about a horizontal axis in such a way that the weight of the sheet serves as a return force and that this sheet is displaced under the action of an inflatable component (13) receiving a compressed air pressure.

8. Device as claimed in claim 7, wherein the sheet (12) supporting the sensor is displaced between two extreme positions fixed by adjustable stops (13, 14) corresponding to the minimum and maximum area of air diffusion and therefore to the respective minimum and maximum flow admitted into the treated space.

9. Device as claimed in anyone of the previous claims, wherein the pneumatic regulation operating fluid is compressed air at a low pressure than 0,2 bar, to facilitate the operation of the inflatable components which operate the motorized damper on the one hand, and ensuring the displacement of the sensor on the other hand.

10. Device as claimed in claim 9, wherein the pressure of the compressed air is about 0,05 bar.

11. Device as claimed in anyone of the previous claims , wherein it includes a deflector (17) placed upstream the variable opening controlled by the movable device (3).

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