EP0638774A1 - Process and device for feeding ventilation air to different rooms of an appartment - Google Patents

Abstract

This process consists of supplying, to different rooms of an apartment, air at stable low pressure, with the aid of a fan (9) at relatively high pressure, of feeding the fan (9) on the one hand with the aid of new air (3, 4) and on the other hand with the aid of recycled air (12, 13), that is to say having been drawn by the fan (9) and not admitted into the apartment, and of adjusting the respective proportions of new air and recycled air, so that the proportion of new air increases and the proportion of recycled air decreases when the ventilation needs increase, and that the proportion of new air decreases and the proportion of recycled air increases when the ventilation needs decrease so that the flow rate of the fan is kept almost constant. Application to installations for controlled mechanical ventilation of apartments. <IMAGE>

Description

The present invention relates to a method and a device for supplying ventilation air to the different rooms of a room.

It is known that the different rooms of a room, such as a dwelling, have variable ventilation needs, depending on their occupancy by people, and according to their conditions of use.

These needs evolve according to cycles which are not foreseeable, and which can be very different from one accommodation to another, or even from one room to another of the same accommodation, or for the same room, vary with during the period of occupation of the accommodation.

There are different techniques for ventilating rooms.

The first technique consists in carrying out a mechanical extraction at a fixed flow rate in the technical rooms, with passive air inlets in the main rooms.

A second technique consists in carrying out a mechanical extraction in the technical parts, controlled by a need in the technical parts, with passive air inlets, controlled or not in the main parts.

A third technique consists in carrying out a double-flow ventilation, consisting of a simple mechanical extraction in the technical rooms and a simple insufflation in the main rooms, the extraction and insufflation being carried out with equal flow rates.

The first and third solutions concern ventilation installations with fixed flows which have little relation to the need for variable flows which currently exists.

The second solution has the advantage of controlling the ventilation to a need expressed in the technical rooms, insofar as the extraction is controlled, and in the main rooms insofar as the air inlets are controlled.

However, the main defect of this latter technique is that it only provides a variation in cross-section of the air inlets and not a variation in actual flow in the rooms where they are installed. Indeed, the flow which passes through the main parts is the same as that which is extracted mechanically in the technical parts. The total extracted flow is distributed in proportion to the surfaces open to the outside in each room. The flow through these parts therefore results from the relative section opening of the air inlets, but also possible leaks from the housing which are distributed randomly and disturb the proper functioning of the assembly.

It should be noted that it is frequent to find accommodation where parasitic leaks are equivalent to the maximum opening section of the air inlets. These leaks are very annoying for the lower flow rates because the air distribution of the extracted flow is then no longer ensured as a function of the sections of the air inlets, but as a function of the sections of the air inlets increased by the leaks.

Similarly, if a window is open in a room, for example, most of the extracted flow comes from this room, and the other rooms, even if they have greater ventilation needs, are poorly ventilated or poorly ventilated.

It must also be taken into account that it is not possible to define an average value of housing leaks, over a large number of housing, which prevents considering a stable pressure on either side of the inlet of air. However, it is this pressure which generates the flow through the passage section.

In addition, the technique of natural air inlets does not make it possible to very effectively combat external noise, due to the pressure drop which, in general, the sound absorption devices cause.

Finally, it is impossible to interpose an effective filter, intended to ensure the retention of dust or the like, between the exterior and the interior of the house, since such a filter requires an operating pressure incompatible with the usual values in transit. natural.

The object of the invention is to provide a device ensuring stability of the pressure of the air admitted into the different rooms of a room, regardless of the random leaks from this room, whatever the flow required in each of the main rooms. , and whatever the external conditions such as wind or temperature.

Another object of the invention is to be able to carry out the filtration of the air admitted into the room and, possibly, the preheating of the latter.

To this end, the process which it relates to consists in supplying the various rooms of the room with air at stable low pressure, using a relatively high pressure fan, supplying the fan, a on the one hand, using fresh air and, on the other hand, using recycled air, that is to say having been driven by the fan and not admitted into the room, and adjusting the respective proportions of fresh air and recycled air, so that the proportion of fresh air increases and the proportion of recycled air decreases, when the ventilation requirements increase, and that the proportion of fresh air decreases and the proportion of recirculated air increases, when ventilation needs decrease, so that the fan flow remains relatively constant.

The stable low pressure is obtained by variable internal recycling on a fan working at substantially fixed flow and pressure (this pressure being between 80 and 180 Pa), the fixed low distribution pressure in the rooms of the room being between 5 and 40 Pa .

According to one embodiment, this method consists in varying, simultaneously and in opposite directions, the valve sections arranged on an opening for supplying fresh air to the fan and on an air recycling duct. .

Advantageously, this process consists in adjusting the proportions of fresh air and recycled air by controlling the difference in pressures prevailing, respectively, upstream of the fan in an area subject to the influences of recycled air and fresh air, and downstream of the fan in an area located upstream of the air supply conduits of the various rooms in the room.

The sections of the valves, arranged on the opening for the supply of fresh air to the fan and on the air recycling duct, vary simultaneously and in opposite directions to increase or decrease the flow of fresh air and decrease or increase the flow recycled air while maintaining a fixed total flow.

According to one possibility, the difference in pressures upstream of the fan and upstream of the supply conduits of the different rooms is defined relative to a reference pressure. The proportions chosen are fixed and not variable.

This reference pressure is obtained by mixing the pressures, respectively, of the fresh air outside the room, and the air inside the room.

According to one possibility, the reference pressure is obtained by mixing from 0.5 to 0.15 times the pressure of the fresh air and from 0.5 to 0.85 times the air pressure inside the room. The proportions chosen are fixed and not variable.

The pressure difference can be read periodically, since it is not necessary to constantly adjust the pressures for use in ventilation, the variations in requirements of the main rooms being always quite slow.

In addition, it is possible to modify the setting only when several successive measurements give the same information, in order to avoid measurement faults which may occur as a result of external elements such as gusts of wind, slamming doors or others.

According to another characteristic, this method consists in having pressure drop elements upstream and downstream of the fan, in order to obtain balanced pressures at the level of the fan and to lower the pressure of the air supplied to the supply pipes of the parts. of the room, in relation to the pressure supplied by the fan.

This allows, although having a fan operating at relatively high pressure, to ensure a low pressure supply to the rooms of the room to be ventilated, which is a factor of comfort in particular limiting noise. Thus, it is possible to create on either side of the fan two compartments in which the pressure will be at an intermediate value, for example 30%, 50% or 70% of the total pressure of the fan.

A device for implementing this method comprises a box having a new air inlet duct communicating with the outside and equipped with a valve, and air outlet nozzles connected to the supply pipes in room air, this box being equipped with a fan, and a recycling duct which, bringing some of the air from the zone comprising the outlet nozzles to the zone comprising the fresh air intake, is fitted with an adjustment valve, the section of which is actuated in synchronism and in the opposite direction to the fresh air inlet valve, keeping the flow rate to the fan fixed.

In addition, upstream and downstream of the fan are provided two chambers delimited for that arranged upstream by a filter and for that arranged downstream by a reduction in section generating substantially the same pressure drop as the filter.

Advantageously, to ensure pressure balancing upstream and downstream of the fan, the section reducing element placed downstream of the filter has a section equal to the equivalent section of the clean filter minus half of the equivalent section variation of the filter during fouling.

According to one possibility, the filter is a winding filter, the renewal movement of which is triggered by exceeding a defined difference between the relative pressures (P _i - P₂) and (P₃ - P _i ) prevailing immediately upstream and downstream of the fan.

According to one embodiment of this device, the valves located on the fresh air inlet and in the recycling duct consist of a single valve in the form of a three-way mixing valve.

• Figures 1 et 2 sont deux vues très schématiques de deux formes d'exécution de ce dispositif ;
• Figure 3 est une vue schématique d'une partie de ce dispositif intégrant un mécanisme de renouvellement automatique d'un filtre à enroulement.
• La figure 1 représente un dispositif comprenant un caisson principal 2 dans une paroi duquel est ménagée une ouverture 3 équipée d'une vanne 4 d'admission d'air. L'air extérieur est à la pression Pe, et l'ouverture 3 et la vanne 4 délimitent un passage S0.

In any case, the invention will be clearly understood with the aid of the description which follows, with reference to the appended schematic drawing representing, by way of nonlimiting examples, several embodiments of this device:

• Figures 1 and 2 are two very schematic views of two embodiments of this device;
• Figure 3 is a schematic view of part of this device incorporating an automatic renewal mechanism of a winding filter.
• FIG. 1 represents a device comprising a main box 2 in a wall of which is formed an opening 3 equipped with an air intake valve 4. The outside air is at pressure Pe, and the opening 3 and the valve 4 delimit a passage S0.

In another wall of the box 2 open ends 5 for connection to air supply ducts of a room. These nozzles correspond to a global section S3 divided in this case into four sections S3.1, S3.2, S3.3 and S3.4.

Inside the main box 2 is disposed a smaller box 6, the end face of which located on the side of the inlet opening 3 is closed by a filter 7 corresponding to a passage section S1, and whose the other end is equipped with an opening 8 of reduced section, corresponding to a passage section S2. A fan 9 is mounted in the middle of this box 6 which it divides into two compartments.

It is a relatively high pressure ventilator, from 100 to 200 Pa, whose pressure / flow operating curve does not require a significant plateau since the ventilator flow is kept substantially constant.

Between the box 6 and the box 2 is formed a duct 12 for recycling the air leaving the box 6, towards the inlet of the latter. On this recycling conduit 12 is mounted a recycling valve 13 providing a passage section S4.

In operation, we will find the pressure P2 in the box 6 upstream of the fan 9, P3 in the box 6 downstream of the fan 9, P4 in the box 2 on the side of the air supply ducts of the room, and P1 of the side of the air inlet 3. A pressure Pi prevails inside the room.

   ou A est compris entre 0,5 et 0,15,
   et B est compris entre 0,5 et 0,85.Using a device 14 not described in detail here, the difference between the pressures P4 and P1 is measured by comparison with a reference pressure which is defined from the pressures Pe and Pi. We have, for example: $$\text{- P ref = A Pe + B Pi}$$

or A is between 0.5 and 0.15,
and B is between 0.5 and 0.85.

The device 14 acts on the valves 4 and 13 so as to close one when it opens the other, in a constant proportion to increase or decrease the flow of fresh air and decrease or increase the flow of recycled air, while maintaining a fixed total flow.

The need for ventilation of the room is expressed by section S3. When S3 varies, S0 must vary so that the air leaving the box to the rooms in the room is replaced by outside air.

If S3 increases, this results in a decrease in P4, and a slight decrease in P1, due to a slight increase in depression. There is an imbalance between P1 and P4, which is detected by the device 14.

The valve 4 is then opened to increase S0 by a quantity fixed in advance corresponding to an incrementing step, and the valve 13 is closed by the same step. If at the next reading the imbalance remains, the valve 4 is opened with an additional step and the valve 13 with an additional step. When the equilibrium defined between the pressures P1 and P4 is again reached, the valves remain in the state in which they are.

If the need for ventilation decreases in the rooms, S3 decreases and this results in an increase in P4 and a slight increase in P1 due to a slight decrease in depression. An imbalance then occurs between the pressures P1 and P4 in the opposite direction to the previous case. This imbalance, detected by the device 14 results in an opening of the valve 13, increase in S4, and a closure of the valve 4, decrease in S0.

The combined use, for obtaining the reference pressure for measuring the imbalance between P1 and P4, of the internal pressure and the external pressure, makes it possible to weight the pressure variations due for example to the wind, or to the triggering of '' additional ventilation such as a range hood. The weighting indicated above makes it possible to minimize these external phenomena.

Another advantage of the invention is to use a fan 9 at high operating pressure, which makes it possible to associate with the device an efficient filter 7 of the air entering the housing. It is in particular possible to filter all the pollens and to retain a good part of the dust usually present in the air of cities or industrial sites.

The filtration device is placed upstream of the fan to protect the mechanical or air treatment components.

The efficiency of filtration is increased by the principle of recycling. In fact, the valve 13 being generally, at least partly open, part of the air which is blown passes several times over the filter, so that it has already purified during its first passage.

When a dwelling is sparsely occupied, the need for ventilation decreases, and the internal recycling of air increases. Consequently, the air blown into the housing during a period of absence from the latter is very clean and the clogging of the filter is slow.

This method and this device have, moreover, the advantage of allowing good isolation of the room from outside noise. It is, in fact, possible to interpose a sound trap between the fresh air intake which can be placed on a facade little exposed to noise and the insufflation box.

It is possible to have an effective sound absorbent because of the localized treatment of the air, and no longer distributed over each air inlet, and the presence of the fan which makes it possible to combat the pressure drop inherent in a device of sound absorption.

It is also possible to heat treat the air inside the room, in particular by heating the recycling air, or by passing it over a cold body, without having to resort to overly complex systems.

FIG. 2 represents a variant of the device of FIG. 1 in which the valves 4 and 13 have been grouped together in a single pivoting valve 16, opening the section S0 of the inlet 3 when it decreases the section S4 of the conduit 12, and vice versa.

The section S2 of the opening 8 makes it possible to maintain the operating position of the fan 9 during the fouling of the filter. S2 is chosen in relation to the pressure drop of the filter and its expected evolution over time. When the filter is clean, S2 is the main pressure drop. The more the filter 7 becomes clogged, the more its equivalent section S1 decreases, its pressure drop gradually increasing to become predominant in front of S2.

This change is detected by control means 14 ′, not described, of the pressures P2 and P3, making it possible to generate either a dirty filter warning signal, or a renewal of the filter if the box is equipped with an automatic renewal filter.

As indicated previously, the section S2 can be chosen to be equal to the equivalent section of the filter in the middle of its life.

The relatively high operating point of the fan and the presence of the pressure drop elements S1 and S2 make it possible to have pressures P2 and P3 which are not insignificant and close to each other in absolute value. P2 is a depression relative to the reference pressure, while P3 is an overpressure.

FIG. 3 represents the device according to the invention in the case of the use of a filter 17 with automatic winding. The device comprises, in this case, a distributor 18 for all or nothing capable of sending, in two pockets 19 and 20, that is to say the pressure P2, or the pressure P3. The two pockets 19 and 20 bear, on the one hand, on a fixed wall and, on the other hand, on a movable wall, respectively 22 and 23, the walls 22 and 23 acting by means of two connecting rods, respectively 24 and 25 on a disc driving, by means of a freewheel mechanism 26, a cable 27 for winding the filter.

The two pockets are also subjected to the action of springs, respectively 28 and 29, tending to oppose their inflation When the pressure sent into the pocket 19 is P2, the spring 28 exerts a force which tends to deflate this pocket. If, on the contrary, it is the pressure P3 which is sent into this pocket, the force exerted by the spring 28 is compensated and, beyond this, by the force developed by the pressure difference between the ambient pressure P2 and the pressure internal P3.

The inflation of the pocket 19 results in an upward displacement of the connecting rod 24 which drives, via the free wheel 26, the cable 27 and consequently the filter 17. Similarly, when a pressure P2 is sent in the bag 20, the pressure difference between the inside and the outside allows the bag to deflate, while equal pressure, in and around the bag, makes it swell by the action of the spring 29.

The distributor 18 controlled by a capsule with a deformable wall makes it possible to pass the pressure sent into the pockets 19 and 20 alternately from P2 to P3. The movement resulting from the movable plates 22 and 23 is transmitted by the connecting rods 24 and 25 to the freewheel 26 which drives the filter 17.

Knowing that this movement is controlled by pressures P2 and P3, it is only when the filter is dirty that its replacement is carried out.

As is apparent from the above, the invention brings a great improvement to the existing technique, by providing a device of simple design, making it possible to stabilize the air supply pressure of the rooms of a room, while ensuring other functions such as filtration of this air, acoustic damping and, possibly, heat treatment of the air.

Claims (16)

Method for supplying ventilation air to the different rooms of a room, characterized in that it consists in supplying the different rooms of the room with air under stable low pressure, using a fan (9) at relatively high pressure, to supply the fan (9), on the one hand, using fresh air (3, 4) and, on the other hand, using recycled air (12, 13 ), i.e. having been driven by the fan (9) and not allowed in the room, and adjusting the respective proportions of fresh air and recycled air, so that the proportion of air new increases and the proportion of recycled air decreases, when the ventilation needs increase, and that the proportion of fresh air decreases and the proportion of recycled air increases, when the ventilation needs decrease, so that the fan flow be kept almost constant. Method according to claim 1, characterized in that it consists in varying, simultaneously and in opposite directions, the valve sections (4, 13) arranged on an opening (3) for supplying fresh air to the fan. and on an air recycling duct (12). Process according to either of Claims 1 and 2, characterized in that it consists in adjusting the proportions of fresh air and recycled air by controlling the difference in the pressures (P1, P4) prevailing, respectively, upstream of the fan (9) in an area subject to the influences of recycled air and fresh air, and downstream of the fan in an area located upstream of the air supply ducts of the various rooms in the room. Method according to claim 3, characterized in that the difference of the pressures (P1) upstream of the fan and (P4) upstream of the supply conduits of the different rooms, is defined relative to a reference pressure. Method according to claim 4, characterized in that the reference pressure is obtained by mixing the pressures, respectively, of the fresh air (Pe) outside the room, and the air (Pi) inside from the local. Method according to claim 5, characterized in that the reference pressure is obtained by mixing 0.5 to 0.15 times the pressure of the fresh air (Pe) and 0.5 to 0.85 times the pressure of the air (Pi) inside the room, the proportion of mixture being fixed. Method according to any one of Claims 1 to 6, characterized in that it consists in having pressure drop elements (7, 8) upstream and downstream of the fan (9), in order to obtain balanced pressures at the level of the fan and to lower the pressure of the air supplied to the room supply conduits, compared to the pressure supplied by the fan. Method according to claim 1, characterized in that the operating pressure of the fan is fixed in the range from 80 to 160 Pa. A method according to claim 7, characterized in that the low pressure (P4) supplied to the room supply conduits is fixed in the range of 5 to 40 Pa. Method according to claim 7, characterized in that the pressure (P2, P3) of the air on either side of the fan (9), between the latter and the pressure drop elements (7, 8), is fixed in the range of 50 to 80 Pa. Device for implementing the method according to any one of claims 1 to 10, characterized in that it comprises a box (2) having a new air inlet duct (3) communicating with the outside and equipped with a valve (4), and air outlet nozzles (5) connected to the air supply ducts of the room, this box being equipped with a fan (9), a recycling duct ( 12) which, bringing some of the air from the zone comprising the outlet nozzles (5) to the zone comprising the fresh air inlet, is provided with an adjustment valve (13) whose section is actuated in synchronism and in the opposite direction to the valve (4) for entering the fresh air, keeping the flow rate to the fan fixed. Device according to claim 11, characterized in that upstream and downstream of the fan (9) are formed two delimited chambers, for that arranged upstream by a filter (7), and for that arranged downstream by a reduction in section (8) generating substantially the same pressure drop as the filter. Device according to claim 12, characterized in that the reducing element (8) of section placed downstream of the filter (7) has a section equal to the equivalent section of the clean filter dimmed by half the variation in equivalent section of the filter during fouling. Device according to any one of claims 12 and 13, characterized in that the filter is a winding filter (17), the renewal movement of which is triggered by exceeding a defined difference between the relative pressures (P _i - P₂ ) and (P₃ - P _i ) prevailing immediately upstream and downstream of the fan. Device according to claim 14, characterized in that the drive for the renewal movement of the filter (17) is obtained, without additional energy, by implementing pressure differences between the upstream and downstream of the fan. Device according to any one of Claims 1 to 15, characterized in that the valves located on the fresh air inlet and in the recycling duct consist of a single valve (16) in the form of a three-way mixing valve .

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