Regulation of the pressure supplied by a fan for extracting or blowing air in a ventilation installation

Abstract

The invention relates to a method for regulating the pressure supplied by a fan with adjustable rotational speed in a ventilation system further comprising: - N air ducts, each connected to a branch of a central unit containing said fan; and - N flow regulators with adjustable orifices, each associated with an air duct. The method comprises a modulation (101) of an orifice of each flow regulator so that the flow through it tends towards a set flow rate per duct, for a current pressure supplied by the fan; and, in parallel with the modulation (101): - the determination (102), among the N flow regulators, of a reference regulator that has the largest orifice; - the adjustment (103) of the pressure supplied by the fan to tend towards obtaining, for this reference regulator, a predefined maximum orifice.

Description

Technical field

[0001] The present invention relates generally to the field of ventilation, and more specifically to a method for regulating the pressure provided by an air extraction or supply fan comprising a turbine with adjustable rotation speed in a ventilation installation, said ventilation installation further comprising: a plurality of air extraction or insufflation ducts, a first end of each air extraction or insufflation duct being connected to an air inlet or outlet connection of a central box comprising said air extraction or insufflation fan; at least one air discharge or inlet duct, and a plurality of flow regulators with adjustable passage opening, each associated with an air extraction or insufflation duct among said plurality of air extraction or insufflation ducts. Technological background

[0002] As schematized on the Figure 1 , a non-limiting example of a known residential ventilation installation comprises a ventilation system comprising a fan 1 for extracting an air flow, preferably placed in a volute of a central box 2 comprising a number N of air inlet tappings such as the three air inlet tappings 3 1 , 3 2 , 3 3 visible on the Figure 1, each connected to a first end of an air extraction duct 4 1 , 4 2 , 4 3 , a plurality of air extraction vents such as the three extraction vents 5 1 , 5 2 , 5 3 each connected to the other end of an extraction duct, and at least one discharge device 6 such as a roof cap, connected to an outlet 7 of the central box 2 via a discharge duct 8. The extraction ducts equipped with extraction vents open for example into wet rooms (bathroom, toilet, kitchen) and are made up of mechanical parts capable of adapting the opening (or passage section) of the air according to one or more parameters such as, but not limited to, the humidity level of the room, the detection of the presence of a person, or by any mechanical action (kitchen pull, etc.). The air extraction fan 1 and the extraction vents are generally independent of each other.The air extraction fan 1 extracts an overall air flow by providing the vents with an overall pressure allowing them to operate at the correct extraction flow rate. Each extraction vent constitutes a flow regulator with adjustable passage opening which operates by modifying the passage section of the air entering the corresponding duct according to the humidity or customer needs without taking into account the state of the centralized extraction fan 1. In a so-called speed jump system depending on the flow rate, the system can detect a variation in the flow rate and adapt the speed of the fan 1 in order to modify the pressure available to the vents.

[0003] For this type of installation, the choice of available pressure for an extraction vent is generally defined so that it can regulate the necessary flow rates regardless of the installation conditions and the needs of the other vents. This can lead to excess consumption of the fan's motorized turbine and unnecessary pressure losses in the air network.

[0004] Alternatively, as shown diagrammatically in the Figure 2 , the extraction vents 5 1 , 5 2 , 5 3 of the Figure 1 are replaced by mouths 5 1 , 52 and 53 whose function is purely aesthetic, and the flow regulators with adjustable passage opening are made up of registers 5 1 " , 5 2 " And 5 3 " each comprising a movable flap, and placed inside the air inlet connections of the central box 2. Each register will adjust the position of the flap in order to meet the extraction flow requirement of the room to which it is connected via the extraction duct, based on information from sensors such as, but not limited to, humidity sensors, VOCs, etc.

[0005] In these register systems, the static pressure provided by the fan is generally regulated to remain constant, but does not constitute optimum operation since the registers must compensate for the excess pressure by maintaining smaller openings, thus creating pressure loss.

[0006] Thus, in most known ventilation systems, the extraction flow rates per duct are often: either well above the needs expressed by the regulations, which generates excess electricity consumption and heat losses; or well below this same need, making the system inoperative due to excess pressure loss.

[0007] There is therefore a need to operate a ventilation system, preferably permanently, at an optimum static pressure provided by the fan which is a compromise between the need for air renewal, the electrical consumption of the ventilation system and heat losses.

[0008] To meet the need to reduce energy consumption while reducing noise pollution, document EP 3 502 580 recommends, in a method for distributing ventilation air blown to or extracted from the rooms of a home through a distribution network comprising distribution ducts and controllable control valves to modulate the distributed air, ensuring transport of the ventilation air at a minimum static pressure in the common supply or extraction trunk of the network. In this document, this minimum static pressure is predetermined by implementing the following steps: each room ventilation request is converted into air flow requests associated with each distribution duct; for each distribution duct, the theoretical pressure value required in the common trunk to ensure the requested flow rate is calculated, considering that only the valve associated with this duct is in the maximum opening position and taking into account the pressure losses during the air's journey in each duct.

[0009] The minimum static pressure value is then determined as the maximum pressure among the theoretical necessary pressure values calculated for all the ducts in the installation. The process continues by calculating, for each control valve, the opening position allowing to obtain, for this minimum static pressure thus determined, the air flow rate requested per duct, then by controlling the control valves so that they position themselves at the calculated opening positions. Finally, pressure regulation is carried out using the calculated minimum pressure as the setpoint and the pressure measured in the common trunk as the measurement.

[0010] A major drawback of the method described in the previous document is that it is sequential and requires determining the minimum static pressure value each time the ventilation requirements change before being able to act on the opening positions of the control valves.

[0011] In addition, a sudden variation in the setpoint induces a risk of acoustic discomfort accompanied by a risk of instability of the system (pumping effect).

[0012] Document EP 1 134 509 A1 describes a method for regulating the pressure supplied by an air extraction or supply fan comprising a turbine with adjustable rotation speed in a ventilation installation. It also describes a ventilation installation. Summary of the invention

[0013] The present invention aims to overcome the limitations of the prior art by proposing a simple solution making it possible to automatically adapt the pressure supplied by the fan to its minimum, without having to calculate it beforehand.

[0014] More specifically, the present invention relates to a method for regulating the pressure provided by an air extraction or supply fan comprising a turbine with adjustable rotation speed in a ventilation installation, said ventilation installation further comprising: a plurality of air extraction or insufflation ducts, a first end of each air extraction or insufflation duct being connected to an air inlet or outlet connection of a central box comprising said air extraction or insufflation fan; at least one air discharge or inlet duct, and a plurality of flow regulators with adjustable passage opening, each associated with an air extraction or insufflation duct among said plurality of air extraction or insufflation ducts, said regulation method comprising a modulation of a passage opening of each flow regulator so that a flow passing through each flow regulator tends towards a flow setpoint per duct corresponding to a need for extraction or air insufflation per duct, for a current pressure supplied by the air extraction or insufflation fan; and being characterized in that it comprises, in parallel with the opening modulation of passage of each flow regulator: a step of determining, from among said plurality of flow regulators, a so-called reference flow regulator which has the largest passage opening; a step of adjusting the pressure supplied by the air extraction or insufflation fan to tend to obtain, for the reference flow regulator, a passage opening corresponding to a predefined maximum passage opening, while respecting the flow setpoint for the duct associated with the reference flow regulator.

[0015] In possible embodiments, the step of adjusting the supplied pressure consists of controlling said supplied pressure in a closed loop by adjusting the rotation speed of the turbine of the air extraction or insufflation fan to reduce the difference between a measurement of said supplied pressure and a pressure setpoint dependent on a current opening position Pos ref< of the reference flow regulator.

[0016] In possible embodiments: if the current opening position Pos ref< of the reference flow regulator is greater than a predefined high level, said pressure setpoint is increased; conversely, if the current opening position Pos ref< of the reference flow regulator is lower than a predefined low level, the pressure setpoint is decreased; if the current opening position Pos ref< of the reference flow regulator is between the predefined high level and the predefined low level, said pressure setpoint is unchanged.

[0017] In possible embodiments, said pressure setpoint is controlled to reduce a difference between the current opening position Pos ref< of the reference flow regulator and a predefined CPOS setpoint.

[0018] Alternatively, said pressure setpoint is determined by fuzzy logic as a function of the current opening position Pos ref< of the reference flow regulator and a current rotation speed of the turbine of the air extraction or supply fan.

[0019] Said predefined maximum passage opening for the reference flow regulator is preferably less than the maximum opening that the reference flow regulator can reach.

[0020] Said predefined maximum passage opening for the reference flow regulator is advantageously between 90% and 98% of the maximum opening that the reference flow regulator can reach.

[0021] In possible embodiments, the modulation of the passage opening and the steps of determining the reference flow regulator and adjusting the pressure supplied by the air extraction or insufflation fan are repeated at each variation of the pressure supplied by the air extraction or insufflation fan and / or at each variation of a flow setpoint per duct corresponding to a need for air extraction or insufflation per duct.

[0022] The present invention also relates to a ventilation installation comprising: a central box comprising an air extraction or blowing fan comprising a turbine with adjustable rotation speed, a plurality of air extraction or blowing ducts, a first end of each air extraction or blowing duct being connected to an air inlet or outlet connection of said central box; at least one air discharge or inlet duct, and a plurality of flow regulators with adjustable passage opening, each associated with an air extraction or blowing duct among said plurality of air extraction or blowing ducts, said installation being further configured to implement the method of regulating the pressure provided by the above-mentioned air extraction or insufflation fan.

[0023] Each flow regulator may be an air extraction or insufflation vent arranged at a second end of the corresponding air extraction or insufflation duct.

[0024] Alternatively, each flow regulator is a register arranged inside the corresponding air inlet or outlet connection of said central box. Brief description of the figures

[0025] The following description with reference to the attached drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented. In the attached figures: There Figure 1 , already described above, schematically illustrates a ventilation installation with adjustable extraction vents; The Figure 2 , already described above, schematically illustrates a ventilation installation with adjustable extraction registers; The Figure 3represents a modeling of the pressure losses corresponding to a ventilation installation with adjustable extraction registers of the Figure 2 ; There Figure 4 illustrates possible steps for a method of regulating the supplied pressure in accordance with the present invention; The Figure 5 illustrates a possible functional diagram of operations that could be implemented to implement the steps of the Figure 4 ; There Figure 6 schematically illustrates a principle of pressure adjustment by threshold level; The Figure 7 schematically illustrates a principle of pressure adjustment by fuzzy logic; The figure 8 schematically illustrates a principle of pressure adjustment by nesting correctors. Description of embodiment(s)

[0026] In the figures, identical or equivalent elements will bear the same reference symbols. The various diagrams are not to scale.

[0027] The invention will be described in the non-limiting context of the air extraction ventilation installation shown diagrammatically in Figure 2 , including: N extraction ducts 4 1 , 4 2 , 4 3 , a first end of each air extraction duct being connected to an air inlet connection 3 1 , 3 2 , 3 3 of a central box 2 comprising an extraction fan 1; at least one air discharge duct 8, and N flow regulators with adjustable passage opening, in the form of motorized dampers 5 1 " , 5 2 " , 5 3 " each associated with an air extraction duct among the N air extraction ducts.

[0028] The invention is also applicable to the case where the flow regulators with adjustable passage opening are air extraction or insufflation vents as shown diagrammatically in the Figure 1 .

[0029] The installation is also considered to include the following elements, not shown on the Figure 2 : at least one main electronic card constituting the intelligence of the system from which all the calculation, measurement and control operations necessary for regulation are launched; a pressure sensor or any means making it possible to measure or estimate the pressure provided by the fan 1 in the central box; sensors capable of determining the ventilation needs in each room into which the ducts open.

[0030] The pressure sensor may, for example, have a measuring point placed between the hood of the extraction fan 1 and the air inlet connections and another measuring point outside to measure the atmospheric pressure P 0 serving as a reference.

[0031] The sensors capable of determining the ventilation requirements are preferably placed in the tappings of the central box 2, for example connected to an electronic card associated with each register and configured to control the register motor and modulate the opening position of the register. These sensors may be capable of detecting the humidity level, the CO 2 level, the presence of a person, and / or any parameters likely to provide information on the air quality.

[0032] The invention is based on the principle of elementary physics which demonstrates that, to operate a ventilation installation permanently at an optimum pressure which is a compromise between the need for air renewal in the building, the electrical consumption of the ventilation system and thermal losses, it is sufficient to have the least possible pressure losses in the installation, which amounts to reducing the available pressure to a minimum, while satisfying the necessary flow rate criteria defined by the regulations.

[0033] In a ventilation installation as shown schematically in the Figure 2, the pressure losses induced by the air network depend on the one hand, on each extraction branch (each branch comprising an extraction duct and, at both ends of the duct, an extraction vent and an extraction register), and on the other hand, on the discharge branch(es) (each discharge branch comprising a discharge duct and a roof cap).

[0034] There Figure 3 represents a model of the air network of an installation similar to that shown schematically on the Figure 2 , comprising N branches referenced B 1 to BN . The following notations and references are used for this diagram: P -< is the static pressure made available by the air extraction fan 1 at the central box 2; P 0 is the atmospheric pressure (considered hereinafter as zero for the sake of simplification); ΔP is the difference between the pressure P 0 and the pressure P -< made available by the air extraction fan 1; PR is the pressure at the outlet 7 of the central box 2, connected to the discharge duct 8; k R is a pressure loss coefficient of the discharge branch composed of the discharge duct 8 and the discharge means 6; ΔP R is the pressure loss of the discharge branch; B i is an i th< branch of the air network (i being an integer varying from 1 to N); P i is the pressure at the inlet of the register 5" i of the branch B i; ΔP i is the pressure loss created by the register 5" i of the branch B i;ΔPg i is the pressure loss created by branch B i , outside register 5" i , in other words, the pressure loss associated with the extraction duct 4 i ; kreg i is the pressure loss coefficient created by register 5" i of branch B i , for a given position of register 5" i , ki is the pressure loss coefficient associated with branch B i , outside register 5" i , in other words, the pressure loss coefficient associated with the extraction duct 4 i ; Q i is the flow rate at each branch B i ; QT is the flow rate of air extraction fan 1, and corresponds to the sum of the flow rates Q i at each branch B i . ;

[0035] The air extraction fan 1 is a fan whose turbine rotates at variable and controllable speed.

[0036] It is known that the pressure loss ΔPg i in each branch B i can be calculated by the following relation (1): [Math. 1] Δ Pg i = k i * Q i a = ΔP − ΔP i in which a is a coefficient allowing to take into account the turbulent effects due to friction inside the ducts which modify the behavior of the pressure drop.

[0037] In possible implementations of the method according to the invention, it can be considered that this coefficient a is equal to 2, so that relation (1) above becomes the following relation (2): [Math. 2] Δ Pg i = k i * Q i 2 = ΔP − ΔP i

[0038] Thus, the only elements likely to add pressure loss to the installation of figures 2 And 3 and on which it is possible to intervene are the registers.

[0039] The search for an optimum in the pressure P -< provided by the fan 1 consists, in accordance with the invention, in ensuring that at least one of the registers (or more generally one of the flow regulators) of the installation is maintained at the largest possible opening while guaranteeing that all the flow requirements per duct are satisfied.

[0040] In accordance with the Figure 4 , a method 100 for regulating the pressure supplied by the air extraction fan 1 at the central box 2 essentially comprises, in accordance with the invention, the steps summarized below, controlled by a controller preferably carried by the main electronic card, the latter being advantageously positioned inside the central box 2: During a step referenced 101 on the Figure 4 , the passage opening of each register 5 i " is modulated so that a flow rate Q i passing through each register tends towards a flow rate setpoint CQ i per duct corresponding to a need for extraction or air insufflation per duct, for a current pressure P -< supplied by the extraction fan 1, measured by the pressure sensor. This step 101 conventionally comprises the determination of the air flow rate passing through each register, the comparison of this determined air flow rate with the flow rate setpoint per duct, and the modulation of the closure of the passage opening according to the result of the comparison. For example, if the register is of the type having a rotating movable flap to more or less close the passage opening, the modulation will consist of controlling the rotation of the flap.

[0041] In parallel with the modulation step 101, the method 100 further comprises, in accordance with the invention, the following steps: During a step 102, the register which has the largest passage opening at the end of step 101 is determined from among the N registers. This register thus determined will constitute a reference register for the following step.

[0042] During a step 103, the pressure supplied by the air extraction fan 1 is then adjusted to tend to obtain, for the reference register determined in step 102, a passage opening of the reference register corresponding to a predefined maximum passage opening, while respecting the flow rate instruction for the duct associated with this reference register.

[0043] In a possible embodiment, step 103 consists of checking, during a step 103a, whether a current opening position Pos ref< occupied by the reference register corresponds to a set position, or at least is between a defined high level and a defined low level, and of carrying out an adjustment 103b (namely an increase or a decrease) of the pressure supplied by the air extraction or insufflation fan 1 as long as the condition of step 103a is not verified.

[0044] Steps 101 to 103 are preferably repeated at each variation in pressure provided by the air extraction fan 1 and / or at each variation in a flow rate setpoint per duct corresponding to a new air extraction requirement.

[0045] There Figure 5illustrates a functional diagram of operations that may be implemented for a possible implementation of the preceding steps 101 to 103: Function block 10 represents the operations carried out to determine the position Pos i that the shutter means of each register must occupy 5 i " (hereinafter referred to for simplicity as the register position 5 i " ) to respect the CQ i flow rate instruction per duct. This position is determined using a two-variable function f such that: [Math. 3] Pos i = f CQ i , ΔP i

[0046] The CQ i flow rate setpoint per duct is determined according to the needs to satisfy the air renewal in the rooms concerned. It can be the result of control laws taking into account the measurements made by the different sensors.

[0047] The function f is determined by experimentation. The function f can be a polynomial regression, a point interpolation function ("mapping"), an equation from fluid dynamics, or any other form of mathematical calculation that can be used to obtain the register position.

[0048] The variable ΔP i is determined by the following relation (4), which results from relation (2) above, in which the flow rate Q i has been replaced by the flow rate setpoint CQ i , and the atmospheric pressure P 0 is considered to be zero: [Math. 4] ΔP i = P − − k i * CQ i 2

[0049] The values of the pressure loss coefficients ki associated with each extraction duct 4 i were determined beforehand and stored in a memory on the main electronic card.

[0050] Each calculated value Pos i is communicated to the relevant register 5 i " so that its shutter means adopts this position. To do this, the main electronic card and the electronic cards associated with each register carry communication means capable of exchanging information on a communication link, preferably a Bus link. In the case where the adjustable opening flow regulators are vents and not registers, the communication link is preferably wireless between the main electronic card and the electronic cards associated with each vent.

[0051] Function block 20 represents the determination of the reference register carried out in step 102 of the Figure 4 , which corresponds to the register which has the largest passage opening at the instant considered. In the following, we note Pos ref< the opening position occupied by the means of closing the reference register, such that: [Math. 5] Pos ref = MAX Pos i

[0052] Stage 103 of the Figure 4 is implemented here by a closed loop control 30 of the pressure P -< supplied by the fan 1 which adjusts, by a command U, the rotation speed of the turbine of the fan 1 to reduce the difference ε between a measurement of the pressure P -< and a pressure setpoint W itself adjusted, at the level of a functional block referenced 40 on the Figure 5 , to obtain, from the opening position Pos ref< occupied by the reference register and determined in step 102, an opening position Pos max ref corresponding to a predefined maximum passage opening, while respecting the flow rate setpoint CQ ref< for the duct associated with this reference register. The corrector 31 used in the closed-loop control 30 can be a proportional corrector, a proportional-integrator corrector, a proportional Integrator Derivative corrector, an RST regulator, a corrector with state feedback control, a corrector with predictive control or any other known corrector.

[0053] It should be noted at this point that the preset maximum opening position Pos max ref is preferably lower than the maximum opening position actually achievable for the reference register. Indeed, when a register is completely open, it is at its maximum saturation position for which we can no longer consider that there is perfect equality between the setpoint CQ i and the actual flow rate Q i so that the relationship (4) above would not be exact. As a non-limiting example, for a conventional register whose maximum opening (100%) can be obtained when the shutter is oriented at 90 degrees, the predefined maximum opening position Pos max ref is preferably greater than or equal to a low level set for example at 90% opening, and less than or equal to a high level set for example at 98% opening.

[0054] The principle of adjusting the pressure setpoint W is based on the observation that, to maintain the flow rate setpoint associated with the duct in which this register is located, any register will adapt its opening position according to the available pressure P -< (functional block 10 and step 101). In other words, if the pressure P -< decreases, both the reference register and the other registers will increase their passage opening to maintain the flow rate corresponding to the flow rate setpoint associated with their branch. On the other hand, if the pressure P -< increases, the registers must reduce their passage opening to maintain the flow rate corresponding to the flow rate setpoint.

[0055] Functional block 40 accordingly applies the previous adjustment principle as follows: if the current opening position Pos ref< occupied by the reference damper is higher than the predefined high level, the pressure setpoint W is increased. It follows that the available pressure P -< will increase, and that the reference damper (as well as all the other dampers) will be commanded to close a little more so as to maintain its flow rate setpoint; conversely, if the current opening position Pos ref< occupied by the reference damper is lower than the predefined low level, the pressure setpoint W is decreased. It follows that the available pressure P -< will decrease, and that the reference damper (as well as all the other dampers) will be commanded to open a little more so as to maintain its flow rate setpoint; if the current opening position Pos ref< occupied by the reference damper is located between the predefined low level and high level, the pressure setpoint W is unchanged.

[0056] Functional block 40 can be realized using threshold level adjustment, as shown diagrammatically in the Figure 6. In this case, the aforementioned high level and low level correspond to the activation thresholds for increasing, respectively, decreasing, the pressure setpoint W. An increase slope 41 and a decrease slope 42 are further used to apply an increase in the setpoint W or a decrease in the setpoint W depending on whether the current opening position Pos ref< occupied by the reference register is greater than the high level, respectively less than the low level. These slopes 41 and 42 both have the dimension of a setpoint over time (for example an increase / decrease of 5 Pascals per minute). The high level, the low level and the two slopes 41, 42 thus constitute the adjustment parameters for the pressure setpoint W. These parameters can be determined as a function of the dynamics of the system, either by calculation, or experimentally, or in any other manner ensuring the convergence and stability of the system.A limiter 43 is advantageously used to ensure that the setpoint W remains within the capacity limits of the air extraction fan 1. Thus, the two limit values Lim min and Lim max of the limiter 43 correspond respectively to the minimum pressure and the maximum pressure that the fan 1 can provide, for respectively a minimum speed and a maximum speed of this fan.

[0057] The functional block 40 can also be produced, as shown diagrammatically in the Figure 7, using the classic principles of adjusting a fuzzy (or fuzzy logic) control (fuzzification then defuzzification). This makes it possible to add, in addition to the input variable Pos ref< , other input variables (for example the speed Vit ref< of the fan turbine). This solution has the advantage of being able to dynamically modify the value of the two slopes 41, 42 of the previous solution, in other words to increase or decrease the pressure setpoint W more or less quickly.

[0058] As a non-limiting example shown schematically on the Figure 7, we determine fuzzy criteria such as "the most open register is fully open", "the most open register is slightly open" on the input variable Pos ref< from block 20, and such as "the fan turbine rotates at low speed", "the fan turbine rotates at high speed" on the input variable Vit ref< . We then perform fuzzy reasoning by applying fuzzy laws such as: if the most open damper is fully open AND the fan impeller is running at low speed, then the pressure must be increased quickly if the most open damper is slightly open AND the fan impeller is running at high speed, then the pressure must be decreased quickly. if the most open damper is fully open AND the fan impeller is running at high speed, then the pressure must be increased slowly if the most open damper is slightly open AND the fan impeller is running at low speed, then the pressure must be decreased slowly. if the most open damper is very open AND the fan is running at normal speed, then the pressure must be maintained.

[0059] We understand here that there are an infinite number of possibilities for achieving fuzzy control. These possibilities are processed during development by successive iterations to arrive at a satisfactory setting allowing the necessary stability for the system but also its reactivity. The application of the principles of fuzzy logic makes it possible to determine the pressure setpoint W. In the non-limiting example of the Figure 7 , this is the result of the acceleration of the fan speed resulting from the de-fuzzification. When the acceleration is zero, the pressure setpoint W is maintained, when the acceleration is negative, the pressure setpoint W decreases more or less quickly, and when the acceleration is positive the pressure setpoint W increases more or less quickly. This is managed by the post-processing block which also preferably includes the limiter 43 described with reference to the Figure 6 .

[0060] The functional block 40 can also be implemented by nesting correctors. This consists of adding to the closed-loop control 30 a regulation loop in which the setpoint W becomes the variable to be controlled as shown diagrammatically in the figure 8 The functional block 40 comprises another control loop, comprising a second corrector 44 and which adjusts, by a command U', the pressure setpoint W to reduce a difference ε' between the current opening position Pos ref< occupied by the reference register and determined in step 102, and a predefined CPOS setpoint (for example a setpoint fixed at 95%), corresponding to the predefined maximum opening position Pos max ref cited above. We also find in the functional block 40 the limiter 43 described in Figure 6, whose role is to ensure that the pressure setpoint W remains within the capacity limits of the air extraction fan 1. This solution may prove less tedious to implement than the previous one since the use of a conventional corrector (Proportional Integrator or Proportional Integrator Derivative type) is well known, as is its adjustment.

[0061] In any case, thanks to the use of the limiter 43, it is guaranteed that the rotation speed of the fan motor will never fall below a minimum speed below which the fan cannot operate.

[0062] It is noted that the functional block 20 on the one hand, and the functional block 40 associated with the closed-loop control 30 on the other hand, interact and cause the system to converge towards a stable state which makes it possible to satisfy the needs of all the ducts while guaranteeing operation at a minimal pressure P-, optimizing the acoustic nuisance and the consumption of the system.Furthermore, having two regulations carried out in parallel, namely on the one hand, the modulation of the passage opening of the registers to tend towards a flow rate setpoint per duct according to the current pressure delivered by the fan, and on the other hand, the adjustment of the pressure delivered by the fan to tend towards obtaining, for the reference register, a passage opening corresponding to a predefined maximum passage opening, makes it possible to avoid having sudden variations in the rotation speed variation setpoint of the turbine of fan 1, even in the case of a sudden variation in one of the flow rate setpoints per duct. This also contributes to optimizing the consumption of the system as well as the acoustic nuisance, because a sudden variation in the rotation speed of the motor is more perceptible to the human ear than a gentle variation.Indeed, as block 40 includes the acceleration / deceleration slopes of the set pressure W (slopes 41 and 42 in the case of the adjustment by threshold level illustrated in the . Figure 6 ; Acceleration output in the case of a fuzzy control illustrated on the Figure 7 ; and correction 44 in the case of a regulation nesting illustrated on the FIG. 8 ), variations in motor speed are dampened in the event of a change in setpoint, promoting continuous stability of the system.

[0063] As indicated previously, the application of relation (4) requires knowledge of the pressure loss coefficients ki associated with the extraction ducts 4 i , these having been determined beforehand and stored in a memory of the main electronic card. These coefficients may have been determined using simulation software in which the installation parameters have been entered (such as the number of ducts, lengths and geometry of the ducts, position of the registers).

[0064] In a preferred variant, these coefficients may have been determined during a self-calibration phase of the installation carried out in situ. Such a self-calibration phase may, for example, include the following steps: the flow regulator associated with the i th< air extraction or insufflation duct is controlled so that it is in an open position and all the other flow regulators so that they are in a closed position; the air extraction or insufflation fan 1 is activated at a given speed; the flow rate QT of the air extraction or insufflation fan 1 is determined and the difference ΔP between the atmospheric pressure P 0 and the pressure P -< made available by the air extraction or insufflation fan 1 is measured.The determination of the flow rate QT can be made by using a fan map previously stored in a memory of the main electronic card, this map giving on the one hand, the value of the flow rate QT as a function of the power absorbed by the fan, its rotation speed and its control, and on the other hand, the pressure P -< made available by the air extraction fan 1 as a function of the flow rate QT . Thus, by measuring the power consumed and the speed of the fan, an estimate of the flow rate QT , and of the pressure P -< can be obtained; the pressure loss coefficient ki is calculated from the determined flow rate QT and the difference ΔP measured by applying the following relation (6): [Math. 6] . k i = ΔP Q T 2 − kreg i in which kreg i is the pressure drop coefficient created by the 5" i register of the branch B i , for a given position of the 5" i register. Each register having been characterized beforehand, the kreg i values are known for each possible flow rate value Q i and for each possible position of the register, and stored in the memory of the main electronic card.

[0065] An advantage of determining in situ the pressure loss coefficients ki associated with the extraction ducts 4 i lies in the fact that the self-calibration phase can be carried out not only when the installation is first put into service, but also at any time during the use of the installation, which makes it possible in particular to take into account a possible change in pressure losses, linked for example to fouling of the extraction ducts.

Claims

1. Method for regulating the pressure provided by an air extraction or insufflation fan (1) comprising a turbine with adjustable rotational speed in a ventilation installation, said ventilation installation further comprising: - a plurality of air extraction or insufflation ducts (41, 42, 43), a first end of each air extraction or insufflation duct (41, 42, 43) being connected to an air inlet or outlet tapping (31, 32, 33) of a central box (2) having said air extraction or insufflation fan (1); - at least one air discharge or inlet duct (8), and - a plurality of flow rate regulators (51, 52, 53; 5 1 " , 5 2 " , 5 3 " ) with adjustable passage opening, each associated with one air extraction or insufflation duct among said plurality of air extraction or insufflation ducts (41, 42, 43), said regulation method comprising a modulation (101) of a passage opening of each flow rate regulator (51, 52, 53; 5 1 " , 5 2 " , 5 3 " ) so that a flow rate passing through each flow rate regulator tends towards a flow rate setpoint per duct corresponding to a need for air extraction or insufflation per duct, for a current pressure provided by the air extraction or insufflation fan (1), and being characterized in that it has, in parallel with the modulation (101) of the passage opening of each flow rate regulator: - a step (102) of determining, among said plurality of flow rate regulators, a flow rate regulator known as reference flow rate regulator, which has the largest passage opening; - a step (103) of adjusting the pressure provided by the air extraction or insufflation fan (1) with the aim of obtaining, for the reference flow rate regulator, a passage opening corresponding to a predefined maximum passage opening, while at the same time respecting the flow rate setpoint for the duct associated with the reference flow rate regulator.

2. Method according to Claim 1, wherein the step (103) of adjusting the provided pressure consists in servo-controlling said provided pressure in a closed loop by adjusting the rotational speed of the turbine of the air extraction or insufflation fan (1) so as to reduce the difference between a measurement of said provided pressure and a pressure setpoint dependent on a current opening position Posref of the reference flow rate regulator.

3. Method according to Claim 2, wherein - if the current opening position Posref of the reference flow rate regulator is greater than a predefined high level, said pressure setpoint is increased; - conversely, if the current opening position Posref of the reference flow rate regulator is less than a predefined low level, the pressure setpoint is decreased; - if the current opening position Posref of the reference flow rate regulator is between the predefined high level and the predefined low level, said pressure setpoint is unchanged.

4. Method according to Claim 2, wherein said pressure setpoint is servo-controlled to reduce a difference between the current opening position Posref of the reference flow rate regulator and a predefined setpoint CPOS.

5. Method according to Claim 2, wherein said pressure setpoint is determined by fuzzy logic as a function of the current opening position Posref of the reference flow rate regulator and of a current rotational speed of the turbine of the air extraction or insufflation fan (1).

6. Method according to any one of the preceding claims, wherein said predefined maximum passage opening for the reference flow rate regulator is less than the maximum opening that the reference flow rate regulator can achieve.

7. Method according to Claim 6, wherein said predefined maximum passage opening for the reference flow rate regulator is between 90% and 98% of the maximum opening that the reference flow rate regulator can achieve.

8. Method according to any one of the preceding claims, wherein the modulation (101) of the passage opening and the steps of determining (102) the reference flow rate regulator and adjusting (103) the pressure provided by the air extraction or insufflation fan (1) are reiterated upon each variation of the pressure provided by the air extraction or insufflation fan (1) and / or upon each variation of a flow rate setpoint per duct corresponding to a need for air extraction or insufflation per duct.

9. Ventilation installation comprising: - a central box (2) having an air extraction or insufflation fan (1) comprising a turbine with adjustable rotational speed, - a plurality of air extraction or insufflation ducts (41, 42, 43), a first end of each air extraction or insufflation duct (41, 42, 43) being connected to an air inlet or outlet tapping (31, 32, 33) of said central box (2); - at least one air discharge or inlet duct (8), and - a plurality of flow rate regulators (51, 52, 53; 5 1 " , 5 2 " , 5 3 " ) with adjustable passage opening, each associated with one air extraction or insufflation duct among said plurality of air extraction or insufflation ducts (41, 42, 43), said installation further being configured to implement a method for regulating the pressure provided by the air extraction or insufflation fan (1) according to any one of Claims 1 to 8.

10. Ventilation installation according to Claim 9, wherein each flow rate regulator (51, 52, 53) is an air extraction or insufflation orifice disposed at a second end of the corresponding air extraction or insufflation duct (41, 42, 43).

11. Ventilation installation according to Claim 9, wherein each flow rate regulator ( 5 1 " , 5 2 " , 5 3 " ) is a register disposed inside the corresponding air inlet or outlet tapping (31, 32, 33) of said central box (2).

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