WO2009081253A1

WO2009081253A1 - Device for controlling an atomizing head of an atomizer for spraying liquids into the air

Info

Publication number: WO2009081253A1
Application number: PCT/IB2008/003506
Authority: WO
Inventors: Jean-Claude Millet
Original assignee: Osmooze
Priority date: 2007-12-26
Filing date: 2008-12-12
Publication date: 2009-07-02
Also published as: FR2925860A1; FR2925860B1

Abstract

The invention relates to an atomizer for spraying liquids into the air, comprising: an atomizing nozzle (30-2); a main reservoir (1); an intermediate reservoir (10) feeding the nozzle; a control device (12) for controlling the filling of the intermediate reservoir from the main reservoir; a device for measuring the liquid level in the intermediate reservoir; and a control member (TPE) for initiating the ejection of an atomizing jet during atomizing cycles, the atomizer being configured so as to adjust an average atomization rate so as to achieve an average set rate, depending on the measured level of the liquid in the intermediate reservoir estimated at the end of an atomization cycle.

Description

DEVICE FOR CONTROLLING A NEBULIZATION HEAD OF A DEVICE FOR THE NEBULIZATION OF LIQUIDS IN THE AIR

The present invention relates to an apparatus for nebulizing liquids in the air, for humidification or air cooling purposes, or for diffusing in particular sanitizers, deodorants, disinfectants, or perfumes. The present invention more particularly relates to a liquid nebulizing apparatus of the type comprising a vibrating capillary tube, having an end forming a nozzle for ejecting a liquid, a supply tank connected to the capillary tube by a pipe, a vibrating means for driving the capillary tube in vibration so that it ejects liquid droplets in a nebulizing jet, and excitation means for applying to the vibrating means an excitation signal. A nebulizing apparatus of the aforementioned type is described in the patent application FR 2,877,241.

Figure 1 shows schematically the conventional structure of a nebulizer apparatus of this type. The apparatus comprises a main tank 1 containing a liquid 36 to be nebulized, and a nebulization circuit NBCT fed by the tank 1. The nebulization circuit NBCT comprises a nebulizing head 30, an intermediate reservoir 33 also containing liquid 36, a pipe 31 connecting the tank 33 to the nebulizing head 30 and a pipe 34 equipped with a pump or a controlled valve 35, connecting the tank 1 to the tank 33. The tanks 1 and 33 are subjected to atmospheric pressure Patm. The nebulizing head 30, substantially horizontal, comprises a capillary tube 30-1 and a nozzle 30-2 for ejecting the liquid. The nebulizing head generally has the shape of a hollow needle with an internal diameter less than a millimeter and a length of a few centimeters, the body of which forms the capillary tube 30-1 and whose distal end, beveled, forms the ejection nozzle 30-2. The nebulizing head 30 is mechanically coupled to a vibrating means, typically a resonator TPE piezoelectric transducer. The TPE transducer is excited by an alternating signal Sv supplied by an excitation circuit EXCT. The EXCT circuit is controlled by a CNCT control circuit which defines the duration of nebulization cycles during which the nozzle 30-2 emits nebulized liquid, and the duration of the periods of rest between the cycles of nebulization. The CNCT circuit also controls the pump 35 and adjusts the level of liquid in the intermediate reservoir 33, which it monitors by means of a level detector 33a.

Under normal operating conditions, the level of the liquid 36 in the intermediate reservoir 21 is at a height h1 of the longitudinal axis of the nebulizing head 30. The reservoir 31 is subjected to the atmospheric pressure Patm, the liquid 36 present in the pipe 34, at the inlet of the nebulizing head 30, is subjected to atmospheric pressure to which is added an overpressure Ph 1 equal to the hydrostatic pressure imposed by the liquid column of height h1, with Ph1 = p * g * h1, where p is the density of the liquid and g the gravity.

When the excitation signal Sv is applied to the TPE transducer, the nebulization head resonates and liquid droplets 32 are ejected, forming a kind of mist of droplets or "nebulizing jet". During nebulization, the nebulizing head 30 is supplied with liquid by capillarity and by gravity (effect of hydrostatic overpressure). Air circulation means such as a fan (not shown) may be provided to increase the range of the nebulizer jet.

At rest, when the nebulizing head 30 is not driven in vibration, the liquid 36 is retained in the nebulization head by capillarity, and the hydrostatic pressure is compensated by the appearance of a convex meniscus 32 of liquid 36 to the end of the nebulizing head, due to the surface tension forces acting on the liquid. Beyond a critical pressure threshold Sh1, the meniscus 32 breaks and the liquid 36 flows through the nebulizing head.

It follows from the foregoing that the level of the liquid in the intermediate tank 33 must be precisely controlled, so that the hydrostatic pressure is kept below the threshold Sh1, which is generally reached with a liquid height of the order of a few millimeters.

Thus, the optimum height h1 depends on the threshold Sh1 and the physico-chemical characteristics of the liquid, in particular the viscosity, the density, and the surface tension forces, as well as the diameter inside the capillary tube of the nebulization head. This height is generally low, of the order of 6 to 12 mm with aqueous or alcoholic solutions and a fogging head whose capillary tube has an internal diameter of the order of 0.6 mm. The height h1 is kept substantially constant by the CNCT circuit, which monitors the level of liquid through the level detector 33a arranged in the tank 33, and activates the pump 35 punctually.

The apparatus which has just been described has other disadvantages. The flow of nebulized liquid is very variable because it depends on many factors such as the internal structure of the capillary tube related to its manufacturing process, the ambient atmospheric conditions (temperature and pressure), the nature of the nebulized liquid, the liquid height above the capillary tube, and the orientation of the capillary tube which can be fixed between the horizontal position and the vertical position. Also, this apparatus is also very sensitive to changes in attitude that move the liquid in the intermediate reservoir 33, as well as other phenomena producing similar effects, such as vibrations transmitted by the external environment. Such changes of attitude or vibrations can cause the flow of drops through the spray head. Indeed, the height h1 being low, the movements of the liquid surface in the intermediate reservoir may cause an exceeding of the critical threshold Sh1 which breaks the meniscus 32 at the end of the nebulizing head.

Furthermore, the pump or valve controlled 35 has a cost that has a significant impact on the cost of the device. The flow rate of the nebulizing head is also very sensitive to atmospheric conditions, and especially to ambient temperature, as well as the nature of the liquid to be sprayed.

It is therefore desirable to improve the operation of a liquid nebulization apparatus of the type comprising a vibrating capillary tube, and in particular, by reducing its sensitivity to its environment and the nature of the liquid to be sprayed. It is also desirable to reduce the cost of manufacturing and operating such an apparatus. It is also desirable that the apparatus can adjust the concentration or composition of active products of the nebulized liquid. In one embodiment, there is provided an apparatus for nebulizing liquids in the air comprising a nebulizing nozzle, a main tank, an intermediate tank supplying the nebulizing nozzle with liquid to be sprayed, a filling control device for controlling filling the intermediate tank from the main tank, a device for measuring the level of liquid in the intermediate tank, a fogging control device for triggering the ejection of liquid droplets into a nebulizing jet by the nebulizing nozzle, during nebulization cycles. According to one embodiment, the apparatus is configured to adjust a mean flow rate of nebulization to reach an average flow rate setpoint, depending on the level of the liquid in the estimated intermediate reservoir at the end of a nebulization cycle.

According to one embodiment, the apparatus is configured to control the device for controlling the filling of the intermediate reservoir so as to fill the intermediate reservoir with a volume of liquid corresponding to a volume of nebulized liquid during a few cycles of nebulization by the nebulization nozzle. to reach a reference level slightly below a maximum level beyond which liquid can flow through the nebulizer nozzle outside the nebulization cycles.

According to one embodiment, the intermediate reservoir has an internal volume up to the reference level corresponding to the volume of liquid completely nebulized in less than 3 seconds by the nebulization nozzle.

According to one embodiment, the intermediate reservoir has an internal volume up to the reference level of between 20 and 30 mm 3.

According to one embodiment, the reference level above the nebulization nozzle is between 6 and 12 mm. According to one embodiment, the measurement of the level of the liquid in the intermediate tank is used to control the device for controlling the filling of the intermediate tank.

According to one embodiment the apparatus is configured to estimate the level of the liquid in the intermediate reservoir at the end of a nebulization cycle from the quantity of liquid poured into the reservoir intermediate to reach the reference level after one or more nebulization cycles.

According to one embodiment, the apparatus comprises a nebulization head comprising a capillary tube whose one end forms the nebulization nozzle, a first vibrating member for driving the vibration nebulizing head so that it ejects droplets of liquid in a jet. nebulizing means, and excitation means for applying to the first vibrating member an excitation signal during the nebulization cycles.

According to one embodiment, the device for controlling the filling of the intermediate reservoir comprises a valve actuated by a piezoelectric means.

According to one embodiment, the device for controlling the filling of the intermediate reservoir produces droplets of liquid.

According to one embodiment, the device for controlling the filling of the intermediate reservoir comprises a cavity that can be filled by gravity by the main reservoir and opening into the intermediate reservoir via at least one nozzle, and a second vibrating member for driving the liquid. in the cavity vibrating so that it is ejected in droplets by the nozzle in the intermediate reservoir, and excitation means for applying to the second vibrating member an excitation signal.

According to one embodiment, the control device comprises a number of nozzles fed by the cavity determined so that the intermediate tank can be filled at least as fast as it is emptied by the nebulizing head. According to one embodiment, the device for measuring the level of the liquid in the intermediate reservoir indicates when the reference level is reached by the liquid in the intermediate reservoir, the level of the liquid in the intermediate reservoir at the end of a cycle of nebulization being determined from a number of liquid droplets introduced by the control device into the intermediate reservoir to reach the reference level.

According to one embodiment, the device for measuring the level of the liquid in the intermediate reservoir measures an electrical resistance whose value is a function of the electrical conductivity of the liquid and the level of the liquid in the intermediate reservoir. According to one embodiment, the intermediate reservoir comprises several compartments formed at a distance from the bottom of the reservoir, in which the liquid can rise by capillary action to increase the quantity of liquid that can be contained in the intermediate reservoir without any liquid being present. flows through the nebulizer nozzle.

According to one embodiment, the level measuring device measures the level of the liquid in a compartment in which no filling nozzles of the intermediate reservoir are open.

According to one embodiment, the apparatus comprises a plurality of main tanks supplying the intermediate tank via a respective intermediate filling control device.

According to one embodiment, one of the main tanks contains a concentrated active product and another one of the main tanks a solvent or a mixture of solvents, the concentrated active product being mixed with the solvent or the solvent mixture in the intermediate tank.

According to one embodiment, the control devices for filling the intermediate reservoir are controlled so that the liquid in the intermediate reservoir contains the active product in a selected concentration. According to one embodiment, the main tanks contain different liquids which are mixed with each other in the intermediate tank.

According to one embodiment, the intermediate tank filling control devices are controlled so that the liquid in the intermediate tank contains liquids from the main tanks mixed in selected proportions.

In one embodiment, there is provided a liquid nebulization system in the air comprising a nebulization apparatus as defined above, and an electrically conductive nebulizing liquid in the intermediate reservoir, the level measuring device being configured to exploit the electrical conductivity of the liquid to be sprayed.

In one embodiment, there is provided a method of nebulizing liquids in air comprising the steps of: controlling the filling of an intermediate reservoir from a main reservoir containing a liquid to be sprayed, feeding a spray nozzle from of the intermediate tank, measure the level of the liquid in the intermediate tank, and control the nebulization nozzle during nebulization cycles, to trigger the ejection of liquid droplets into a nebulization jet. According to one embodiment, the method comprises steps of adjusting an average nebulization flow rate to achieve an average flow rate setpoint, depending on the level of the liquid in the intermediate reservoir measured at the end of a nebulization cycle.

According to one embodiment, the method comprises a step of filling the intermediate reservoir with a volume of liquid corresponding to a volume of liquid nebulized during a few cycles of nebulization, to reach a reference level slightly below a maximum level beyond which liquid can flow through the nebulizer nozzle outside the nebulization cycles. According to one embodiment, the intermediate reservoir has an internal volume up to the reference level corresponding to the volume of liquid completely nebulized in less than 3 seconds by the nebulization nozzle.

According to one embodiment, the reference level above the nebulization nozzle is between 6 and 12 mm.

According to one embodiment, the measurement of the level of the liquid in the intermediate tank is used to control the device for controlling the filling of the intermediate tank.

According to one embodiment, the method comprises a step of estimating the level of the liquid in the intermediate reservoir at the end of a nebulization cycle as a function of the quantity of liquid poured into the intermediate reservoir to reach the reference level, after one or more nebulization cycles.

According to one embodiment, the nebulizing nozzle is located at one end of a capillary tube, the method comprising a step of driving the capillary tube in vibration so that the nebulization nozzle ejects liquid droplets into a nebulizing jet during each nebulization cycle. According to one embodiment, the filling of the intermediate tank from the main tank is controlled by a valve actuated by a piezoelectric means.

According to one embodiment, the filling of the intermediate reservoir from the main reservoir is carried out by the projection of liquid droplets into the intermediate reservoir.

According to one embodiment, the filling of the intermediate reservoir from the main reservoir comprises steps of: gravity filling from the main reservoir of a cavity opening into the intermediate reservoir by at least one nozzle, application of a signal of excitation to a second vibrating member, and applying vibrations generated by the second vibrating member to the liquid contained in the cavity, in order to eject liquid droplets through the nozzle into the intermediate reservoir. According to one embodiment, the number of nozzles fed by the cavity is determined so that the intermediate tank can be filled at least as quickly as it is emptied during the nebulization cycles.

According to one embodiment, the level of liquid in the intermediate reservoir at the end of a nebulization cycle is determined from a number of liquid droplets introduced into the intermediate reservoir to reach a reference level.

According to one embodiment, the measurement of the level of the liquid in the intermediate reservoir exploits the electrical conductivity of the liquid to be sprayed.

According to one embodiment, the step of adjusting the average flow rate is performed by filling the intermediate reservoir with a constant volume of liquid after each nebulization cycle, periodically adjusting the level of the liquid in the reservoir to the reference level. , by estimating the quantity of liquid thus added.

According to one embodiment, the liquid in the intermediate reservoir rises by capillary action in compartments formed at a distance from the bottom of the intermediate reservoir. According to one embodiment, the level of the liquid is measured in a compartment in which the intermediate tank filling nozzles do not open.

According to one embodiment, the intermediate tank is supplied with liquid to be atomized by several main tanks via a respective intermediate filling control device.

According to one embodiment, one of the main tanks contains a concentrated active product and another one of the main tanks a solvent or a mixture of solvents, the concentrated active product being mixed with the solvent or solvent mixture in the following intermediate tank a selected concentration of active product.

According to one embodiment, the method comprises a step of mixing in the intermediate tank different liquids each coming from one of the main tanks in selected proportions. According to one embodiment, the liquids contained in the main tanks are perfumes, and each correspond to the base, heart and head notes of a perfume obtained in the intermediate tank.

Exemplary embodiments of the invention will be described in the following, by way of nonlimiting example, with reference to the appended figures among which:

- Figure 1 previously described schematically shows a conventional nebulizer device,

FIG. 2 schematically represents in section and in perspective a nebulizing device according to a first embodiment,

FIG. 3 schematically represents in section the intermediate reservoir of the nebulization device of FIG. 2;

FIG. 4 is a schematic sectional and perspective partial view of a nebulization device according to a second embodiment, FIG. 4A shows in section a detail of the device of FIG. 4,

FIG. 5 schematically represents in section and in perspective a nebulizing device according to a third embodiment,

- Figure 6 shows schematically in section and in perspective a nebulizing device according to a fourth embodiment. Figure 2 schematically shows an embodiment of a vibrating capillary tube type nebulizer apparatus. The apparatus comprises a main reservoir 1 containing a liquid 36 to be atomized, and a nebulization circuit NBCT1 fed by the reservoir 1. The nebulization circuit NBCT comprises a nebulizing head 30, an intermediate reservoir 10 also containing liquid 36, a pipe 34 connecting the tank 10 to the tank 1, and a filling control device 12 for controlling the filling of the tank 10 from the tank 1. The nebulizing head 30 opens directly into a lower region of the tank 10. The tanks 1 and 10 are subjected to atmospheric pressure. The nebulizing head 30, substantially horizontal, comprises a capillary tube 30-1 and a nozzle 30-2 for ejecting the liquid. The nebulizing head generally has the shape of a hollow needle forming the capillary tube 30-1 and having an internal diameter less than one millimeter or of the order of 1 mm, and a length of a few centimeters. The distal end of the nebulization head is beveled and forms the ejection nozzle 30-2. The nebulizing head 30 is mechanically coupled to a vibrating means, generally a piezoelectric transducer TPE1 with resonator. The transducer TPE1 is excited by an alternating signal Sv1 supplied by an excitation circuit EXCT1. The circuit EXCT1 is controlled by a control circuit CNCT1 which defines the duration of nebulization cycles during which the nozzle 30-2 emits nebulized liquid, and the duration of the periods of rest between the nebulization cycles. The circuit CNCT1 also controls the filling control device 12 to adjust the level of the liquid 36 in the intermediate tank 10, which it monitors by means of a level measuring device 14.

According to one embodiment, the intermediate reservoir 10 has an internal volume that can be occupied by the liquid to be sprayed to a reference level, corresponding only to the quantity of liquid nebulized for a few seconds of nebulization, or a few cycles nebulization, taking into account the possible durations of nebulization cycles of the device. In other words, the useful internal volume of the intermediate reservoir 10 is of the order of three to ten times the internal volume of the capillary tube 30-1. For example, if the duration of the nebulization cycles can be 340 ms or 1 s, and if the capillary tube has an internal diameter of 0.6 mm, the volume of liquid nebulized during a cycle of 340 ms is of the order of 4.2 mm3, and reached 12.35 mm3 with a nebulization cycle of one second. Furthermore, to prevent liquid from flowing through the nozzle 30-2 out of the nebulization cycles due to too high hydrostatic pressure in the tank 10, the difference between the level of the liquid in the tank 10 and the level of the nozzle 30-2 should not exceed 6 mm to 12 mm for most liquids that may be nebulized.

For example, the intermediate reservoir has a useful volume that can contain liquid for 6 cycles of nebulization at 340 ms or 2 cycles of nebulization at 1 s. In this example, the reservoir therefore has a useful volume of the order of 25 mm 3, a useful height (above the level of the nozzle 30-2) of 6 mm, and a horizontal section of the order of 4, 5 mm2. Under these conditions, the level of the liquid 36 in the reservoir 10 varies from about 17% with each nebulization cycle of 340 ms and about 50% with each cycle of 1 s. Such level variation is sufficient to be detectable by current and inexpensive level measurement devices.

In the example of Figure 2, the nozzle 30-2 is substantially at the bottom of the tank 10 and the tank 10 has a parallelepipedal inner shape having a width of 2 mm, a length of 2.1 mm and a height 9 mm. The reservoir 10 can thus be filled with the liquid to be sprayed to a maximum height of 6 mm. Of course, the nozzle 30-2 may also be located above the level of the bottom of the tank. In this case, the liquid can still reach the nozzle by capillarity, but a slight decrease in the nebulization rate can be observed when the level of the liquid in the reservoir is below the level of the nozzle 30-2.

If for the sake of clarity in Figure 2, the tank 1 has been shown smaller than the tank 10, it goes without saying that these dimensions are not at all representative of the actual dimensions of these two tanks. The main tank 1 is of course much larger than the intermediate tank, so as to give the apparatus a autonomy in liquid to nebulize the largest possible, to reach several months.

The filling control device 12 can be of two types depending on whether the filling orifice of the reservoir 10 can be closed by the control device 12, or is small enough to prevent the liquid from flowing out by capillary retention of a fluid. meniscus formed on the orifice.

In the first type, the control device 12 may be a simple controlled valve. In the second type, the filling control device 12 may be a microfluidic motor such as that described in US Pat. No. 6,790,011.

In the second type, the control device 12 may alternatively apply the inkjet printhead technology. Thus, the device 12 comprises a cavity 12-1 opening into the intermediate reservoir 10 by a nozzle 12-2. The cavity is closed on the opposite side to the nozzle by a plate 12-3 capable of being vibrated by means of vibrating means, such as a piezoelectric transducer TPE2 with a resonator mechanically coupled to the plate 12 -3. The transducer TPE2 is excited by an alternating signal Sv2 supplied by the circuit EXCT1.

This perfectly proven technology makes it possible to produce drops of the order of 0.1 mm in diameter at a frequency of the order of 2 kHz with a nozzle of 50 μm in diameter. The cost of an inkjet print head is significantly lower than that of a valve or pump with dimensions of the same order of magnitude. In addition, this technology allows precise control of the amount of liquid supplied with sufficient repeatability.

In practice, to overcome the risk of inadvertent flow of liquid from the main reservoir 1 in the intermediate reservoir, and taking into account the viscoelastic properties, and in particular, the surface tension of fluids generally nebulized, and a gap maximum level between the surface of the liquid in the main tank 1 and the nozzle 12-2 of the order of 10 cm, it is preferable to reduce the diameter of the nozzle 12-2 to a value of the order of 20 μm . The diameter of the drops produced by the device 12 then goes to 40 microns. As a result, the device 12 must produce about 125,000 drops to bring the reservoir 10 the amount of liquid corresponding to a nebulization cycle of 340 ms, and 370,000 drops for a nebulization cycle of 1 s. As a result, the filling time required to supply the quantity of liquid emitted during a nebulization cycle is about 63 s for a cycle of 340 ms and about 185 s for a cycle of 1 s. In order to be able to reach rates corresponding to rest periods of 30 seconds, several nozzles 12-2 can be provided between the cavity 12-1 and the interior of the tank 10. If the device 12 comprises, for example, 12 nozzles, the time Filling time is reduced to less than 6 s for a nebulization cycle time of 340 ms and less than 16 s for a cycle time of 1 s. The number of nozzles 12-2 can be adjusted so that the filling ends just before the next nebulization cycle. Thus, the liquid in the vicinity of the inlet of the capillary tube 30-1 is in a certain state of agitation resulting from the filling mode of the intermediate reservoir. Moreover, if it is desired that the filling time of the reservoir

10 corresponds to the duration of the nebulization cycle, the number of nozzles can be increased to about 185, which is perfectly compatible with the current technology of inkjet print heads which currently include 256 nozzles. On the other hand, the number of nozzles 12-2 can also be determined according to a goal of desired trouble-free operating time.

According to one embodiment, slats that are slightly spaced apart from each other or capillary tubes are immersed in the liquid of the intermediate reservoir 10, so as to form compartments above the bottom of the reservoir, in which the liquid can rise by capillary action. This device makes it possible to reduce the hydrostatic pressure and thus reduce the risk of inadvertent flow of liquid through the nozzle 30-2, while increasing the amount of liquid that can be retained in the reservoir 10. This arrangement also makes it possible to reduce the sensitivity of the device to changes of attitude and vibrations.

Thus, Figure 3 shows an intermediate reservoir 10a which differs from the reservoir 10 in that it comprises vertical lamellae or one or more vertical tubes 15 immersed in the liquid contained in the reservoir. The width of the compartments thus formed between the lamellae and the walls of the tank or in the tubes and between the tubes and the walls of the reservoir is preferably chosen less than 1 mm so that the liquid rises along the walls by capillarity. For a given reservoir base surface, the volume of liquid in the reservoir 10a can thus be increased in a proportion depending on the width of the compartments, and the contact angle θ between the liquid and the vertical walls (or the surface tension of the liquid). However, if the width of the compartments is less than a minimum value, the liquid may not sink by gravity when the tank empties.

For example, if the width of the compartments is chosen equal to 0.78 mm, a 50% increase in the liquid that can be contained in the intermediate reservoir is obtained when the liquid has a contact angle θ greater than 35 °. Thus, if the maximum height of liquid in the intermediate reservoir in the absence of compartments is 6 mm, it can reach 9 mm in the presence of compartments. The intermediate reservoir can thus contain the equivalent of 3 additional nebulization cycles. However, the effect of the compartments can be exploited not to increase the maximum amount of liquid in the intermediate reservoir, but to reduce the risk of runoff caused by changes of attitude or vibrations applied to the nebulizer device.

FIG. 4 represents an embodiment of the nebulization apparatus in which the intermediate reservoir comprises one or more compartments in which the liquid can ascend by capillarity. For this purpose, the intermediate tank 10b shown in Figure 4 comprises one or more partitions 15 immersed in the liquid to a distance from the tank bottom, defining two or more compartments 15-1, 15-2. The capillary tube opens into the reservoir 10b in a lowered region of the tank bottom. The filling control device 12 of the reservoir 10b, of the inkjet printing head type, is formed in a lid 16 of the tank 10b. Thus the lid 16 comprises a cavity 12-1 communicating laterally with the pipe 34 connecting the tanks 1 and 10b and comprising nozzles 12-2 opening into a compartment 15-1 of the tank by the base of the lid 16. The upper part of the cavity 12-1 is closed by a plate 12-3 which is subjected to vibrations to trigger the emission of droplets by the nozzles 12-2.

The level measuring device 14 is placed in a compartment

15-2 in which do not open the nozzles 12-2, for example on one of the partitions 15, not to be disturbed by the turbulence generated by the filling control device 12, which can make the level of the liquid in the very unstable compartment.

FIG. 4A represents in section along a vertical plane perpendicular to the sectional plane of FIG. 4, the cover 16, the cavity 12-1 with several nozzles 12-2 opening vertically into the reservoir 10b, the cavity being associated with a vibrating plate 12-3 single.

The level measuring device 14 may be a simple level detector for determining whether the maximum level in the tank 10 is reached or not. The level detector can for example exploit the fact that certain liquids can be electrically conductive. For this purpose, the level detector comprises two electrical contact elements, one being placed towards the bottom of the tank so as to always be in contact with the liquid in the tank, and the other being placed at the maximum level that can reach the liquid in the tank. Thus, the contact between the two contact elements is established only when the level of the liquid in the tank has reached its maximum level. The filling control device 12 is then triggered to fill the intermediate reservoir as soon as the level detector detects that the level of the liquid in the reservoir is below its maximum level. Alternatively, the level measuring device 14 may be an electrical resistance arranged vertically in the reservoir, the level of the liquid in the reservoir being determined by a resistance measurement whose value depends on the electrical conductivity of the liquid and the level of the liquid in the reservoir. The reservoir. A level measurement can be taken at the end of each nebulization cycle or at the end of several nebulization cycles.

It should be noted that most perfumes are in the form of electrically nonconductive oils. Measuring the level of such a liquid is therefore only possible by mixing it with an electrically conductive solvent. In another embodiment, the level measuring device 14 may also include an optical distance sensor installed in the intermediate reservoir 10 for measuring the distance of the level of the liquid in the reservoir. In another embodiment, the intermediate reservoir 10 is placed at atmospheric pressure by a hole whose dimensions are calibrated, the hole being associated with an air flow sensor. The level of the liquid in the intermediate tank is estimated from the measurement of the air flow supplying the volume of liquid entering or leaving the intermediate tank.

It should be noted that the provision of an intermediate reservoir of relatively large height useful with respect to its width or its length makes it possible to obtain greater variations in the level of liquid at each nebulization cycle and therefore better accuracy in the evaluation. the volume of nebulized liquid.

The control circuit CNCT1 can control the transducer TPE1 so as to adjust the average flow rate of nebulized liquid to reach a setpoint, and thus maintain substantially constant the average amount of nebulized liquid at each cycle, using level measurement provided by the level sensor 14. This adjustment can be made by changing the duration of the nebulization cycles and / or the duration of the rest periods between the nebulization cycles. This adjustment can be done in real time as follows. The intermediate tank is filled to a reference level before each new nebulization cycle. The nebulization is then stopped when the level sensor 14 indicates that a minimum level is reached or when the intermediate reservoir is empty.

The adjustment of the average nebulization flow rate may also comprise a step of estimating this average flow rate. The estimation of the average flow rate of nebulization can be carried out by determining after each nebulization cycle the number of drops or the volume that it was necessary to introduce into the intermediate reservoir to reach the reference level. The sum of the volumes of liquid thus introduced into the intermediate reservoir over a period of a few cycles of nebulization can then be calculated and then compared with a theoretical value obtained at from the average setpoint flow. The duration of the nebulization cycles or the duration of the rest periods is then adjusted according to the difference between the calculated volume and the theoretical value.

The estimation of the average nebulization flow rate can also be carried out by filling the intermediate reservoir with a constant number of drops or a constant volume of liquid after each nebulization cycle. Periodically, the level of the liquid in the tank 10 is measured and adjusted to the reference level. The quantity of liquid thus added or not added makes it possible to estimate the average flow rate of nebulization. The duration of the nebulization cycles or the duration of the rest periods is then adjusted according to the estimated flow over the period.

It can be expected to issue an alarm when the estimated flow deviates too much from a theoretical value.

Figure 5 shows another embodiment of the nebulizer apparatus. In FIG. 5, the nebulizer apparatus differs from that shown in FIG. 2 in that it comprises a NBCT2 nebulization circuit and two main reservoirs 1a, 1b supplying the intermediate reservoir 10c. The reservoir 1a is intended to contain a solvent or a mixture of solvents and the reservoir 1b, of smaller dimensions, a concentrated active product.

Each tank 1a, 1b is associated with a respective filling control device 12a, 12b for controlling the filling of the intermediate tank 10c from the main tank.

Each filling control device 12a, 12b may be of the type shown in FIG. 2. Thus each device 12a, 12b comprises a cavity fed by the corresponding main reservoir 12a, 12b, opening into the reservoir 10c and closed by a plate mechanically coupled to vibrating means TPE2a, TPE2b, such as a piezoelectric resonator transducer. Each vibrating means is controlled by a respective excitation signal SV2a, SV2b resulting from an excitation circuit EXCT2. The excitation circuit EXCT2 is controlled by a control circuit CNCT2 which also receives a signal for measuring the level of the level measuring device 14. The control circuit CNCT2 can thus determine the volume of nebulized liquid during one or more cycles. of nebulization. The control circuit CNCT2 is configured to calculate the number of drops to be extracted from each of the main tanks 1a, 1b so that the liquid contained in the intermediate tank 10c has a concentration of active product corresponding to a set value supplied. The control circuit then controls the fill control devices 12a, 12b to output the calculated number of drops that mix in the intermediate tank 10c.

The drop filling technique makes it possible to very finely adjust the concentration of active product of the nebulized liquid. The concentration of active product of the liquid in the tank 10c can thus be adjusted between 0 and 100%, for example between 2.5% and 10%.

Figure 6 shows another embodiment of the nebulizer apparatus. In FIG. 6, the nebulizer apparatus differs from that shown in FIG. 2 in that it comprises a NBCT3 nebulization circuit comprising several main tanks 1c, 1d, 1e feeding the intermediate reservoir 10c, the liquids 36c, 36d , 36th contents in the main tanks can be different. Each main tank 1c, 1d, 1e is associated with a respective filling control device 12c, 12d, 12e to control the filling of the intermediate tank 10d from the main tank.

Each filling control device 12c, 12d, 12e may be of the type shown in FIG. 2 and mechanically coupled to vibrating means TPE2c, TPE2d, TPE2e. Each vibrating means is controlled by a respective excitation signal SV2c, SV2d, SV2e resulting from an excitation circuit EXCT3. The excitation circuit EXCT3 is controlled by a control circuit CNCT3 which also receives a signal for measuring the level of the level measuring device 14. The control circuit can thus determine the volume of liquid nebulized during one or more cycles of nebulization. The control circuit CNCT3 can calculate the number of drops to be extracted from each of the main tanks 1c, 1d, 1e so that the mixture contained in the intermediate tank 10c has a liquid composition 36c, 36d, 36e corresponding to set values provided. . The control circuit then controls the filling control devices 12c, 12d, 12e to emit the calculated number of drops which are mixed in the intermediate tank 10c The drop filling technique makes it possible to very finely adjust the respective proportions of the liquids 36c, 36d, 36e introduced into the intermediate tank 10d. The nebulizing apparatus with several main tanks 1c, 1d,

It can be used to successively diffuse several different active products, for example several different perfumes. The passage from one active product to another can be carried out after emptying the intermediate tank. With cycles of 340 ms and an intermediate tank that can contain the amount of liquid corresponding to 6 nebulization cycles, the change of active product can be carried out in about 4 s corresponding to emptying and filling the tank 10d. If one of the tanks 1c, 1d, 1e contains a solvent or a mixture of solvents, it can be provided an intermediate cleaning phase of the intermediate tank 10d during which the intermediate tank is filled only solvent or solvent mixture .

The passage from one active product to another may also be carried out progressively, or the nebulizing apparatus may be used by mixing the liquids contained in the main tanks 1c, 1d, 1e in the intermediate tank 10d.

Thus, if the active products contained in the main tanks are perfumes, they can be assembled as described in US Pat. No. 6,790,011. Furthermore, the composition of a perfume generally results from the assembly of three "notes", namely a note of funds, a note of heart and a note of head. By filling the main tanks with a base of funds, a base of heart and a base of head, the apparatus can diffuse perfumes of different compositions belonging to the same "olfactory universe.

One of the tanks can also be used to contain a solvent or a mixture of solvents, the other tanks being filled with different concentrated active products. Thus, active products can be diffused into the air in proportions and concentrations that can evolve over time depending on the needs of the user or environmental parameters. If the nebulizer apparatus shown in FIG. 6 comprises three filling heads, it goes without saying that four main tanks can be provided if it is desired to have three tanks containing different concentrated active products such as perfumes, and one tank containing a solvent. The main tanks of perfume concentrates can be much smaller than the solvent tank. As a result, the intermediate tank fill nozzles can be of different sizes depending on whether they communicate with the solvent tank or a perfume concentrate tank. It will be apparent to those skilled in the art that the present invention is capable of various alternative embodiments. In particular, the invention is not limited to a vibrating capillary tube nebulizing head. The nebulization apparatus according to the invention can be produced using other types of nebulization heads such as those described in patent EP 0 714 709 comprising ejection channels subjected to vibrations, or to any other form nebulization using piezoelectricity or electrostatics.

Other devices for controlling the filling of the intermediate reservoir can also be envisaged. Indeed, the invention can be carried out with a simple solenoid valve controlling the flow of liquid from the main reservoir (s) to the intermediate reservoir. Other types of valves can also be used for this purpose such as valves actuated by a piezoelectric means to release the liquid. Moreover, other embodiments can easily be envisaged from the foregoing description. Thus, the intermediate tank 10c or 10d can also be provided with compartments. In this case, all the nozzles 12-2 of the filling control devices can open into the same compartment so that the liquids from the main tanks are better mixed, while the level measuring device is installed in a compartment in which no nozzle does not open.

Claims

1. Apparatus for nebulizing liquids in the air comprising a nebulizing nozzle (30-2), a main reservoir (1), an intermediate reservoir (10) supplying the nebulizing nozzle with liquid to be sprayed, a control device ( 12) to control the filling of the intermediate tank from the main tank, a device for measuring the liquid level in the intermediate tank, a nebulizing control unit (TPE) for triggering the ejection of liquid droplets into a tank. nebulizing jet by the nebulization nozzle, during nebulization cycles, characterized in that it is configured to adjust an average nebulization flow rate to achieve an average flow rate setpoint, depending on the level of the liquid in the intermediate reservoir (10 ) estimated at the end of a nebulization cycle.

2. Apparatus according to claim 1, configured to control the control device (12) for filling the intermediate reservoir (10) to fill the intermediate reservoir with a volume of liquid corresponding to a volume of nebulized liquid during a few cycles of nebulization by the nebulizing nozzle (30-2), to reach a reference level slightly lower than a maximum level beyond which liquid can flow through the nebulizing nozzle outside the nebulization cycles.

3. Apparatus according to claim 1 or 2, wherein the intermediate reservoir (10) has an interior volume up to the reference level corresponding to the volume of liquid nebulized completely in less than 3 seconds by the nebulizing nozzle (30-2) .

4. Apparatus according to one of claims 1 to 3, wherein the intermediate reservoir (10) has an interior volume up to the reference level between 20 and 30 mm3.

5. Apparatus according to one of claims 1 to 4, wherein the reference level above the nebulizing nozzle (30-2) is between 6 and 12 mm.

6. Apparatus according to one of claims 1 to 5, wherein the level measurement of the liquid in the intermediate tank (10) is used to control the control device (12) of the filling of the intermediate tank.

7. Apparatus according to one of claims 1 to 6, configured to estimate the level of the liquid in the intermediate tank (10) at the end of a nebulization cycle from the quantity of liquid discharged into the intermediate tank (10). ) to reach the reference level after one or more nebulization cycles.

8. Apparatus according to one of claims 1 to 7, comprising a nebulizing head comprising a capillary tube (30-1), one end of which forms the nebulizing nozzle (30-2), a first vibrating member (TPE) for driving the vibration nebulizing head so that it ejects liquid droplets into a nebulizing jet, and excitation means (EXCT) for applying to the first vibrating member an excitation signal (Sv) during the nebulization cycles.

9. Apparatus according to one of claims 1 to 8, wherein the control device (12) of the filling of the intermediate reservoir (10) comprises a valve actuated by a piezoelectric means.

10. Apparatus according to one of claims 1 to 8, wherein the control device (12) of the filling of the intermediate reservoir (10) produces droplets of liquid.

11. Apparatus according to claim 10, wherein the control device (12) for filling the intermediate reservoir (10) comprises a cavity (12-1) capable of being filled by gravity by the main reservoir (1) and opening into the intermediate reservoir by at least one nozzle (12- 2), and a second vibrating member (TPE2) for driving the liquid into the vibrating cavity to be ejected in droplets (13) through the nozzle into the intermediate reservoir, and excitation means (EXCT2) for applying the second vibrating member an excitation signal (Sv2).

12. Apparatus according to claim 11, wherein the control device (12) comprises a number of nozzles fed by the cavity (12-1) determined so that the intermediate tank (10) can be filled at least as fast that it is emptied by the nebulizing head (30).

13. Apparatus according to one of claims 1 to 12, wherein the device (14) for measuring the level of the liquid in the intermediate tank (10) indicates when the reference level is reached by the liquid in the intermediate tank, the liquid level in the intermediate reservoir at the end of a nebulization cycle being determined from a number of liquid droplets introduced by the control device (12) into the intermediate reservoir to reach the reference level.

14. Apparatus according to one of claims 1 to 12, wherein the device (14) for measuring the level of the liquid in the intermediate reservoir.

(10) measures an electrical resistance whose value is a function of the electrical conductivity of the liquid and the level of the liquid in the intermediate reservoir.

15. Apparatus according to one of claims 1 to 14, wherein the intermediate tank (10a, 10b) comprises several compartments (15-1, 15-2) formed at a distance from the bottom of the tank, in which the liquid (36) can go up by capillarity to increase the amount of liquid that can be contained in the intermediate reservoir without liquid flowing through the nebulizing nozzle (30-2).

Apparatus according to claim 15, wherein the level measuring device (14) measures the level of the liquid in a compartment (15-2) in which no filling nozzles (12-2) of the intermediate reservoir ( 10b).

17. Apparatus according to one of claims 1 to 16, comprising a plurality of main tanks (1a-1e) supplying the intermediate tank (10c, 10d) via a respective intermediate filling control device (12a-12e). .

Apparatus according to claim 17, wherein one of the main tanks (1a, 1b) contains a concentrated active product and another one of the main tanks a solvent or a mixture of solvents, the concentrated active product being mixed with the solvent or the solvent mixture in the intermediate tank (10c).

Apparatus according to claim 18, wherein the control devices (12a, 12b) for filling the intermediate reservoir are controlled so that the liquid in the intermediate reservoir (10c) contains the active product in a selected concentration.

20. Apparatus according to claim 17, wherein the main tanks (1c, 1d, 1e) contain different liquids which are mixed with each other in the intermediate tank (1 Od).

Apparatus according to claim 20, wherein the control devices (12c, 12d, 12e) for filling the intermediate tank are controlled so that the liquid in the intermediate tank (10d) contains liquids from the main tanks (1c, 1d). , 1e) mixed in selected proportions.

22. System for nebulizing liquids in air, characterized in that it comprises a nebulizing apparatus according to one of claims 1 to 21, and an electrically conductive nebulizing liquid in the intermediate reservoir (10), the device for level measurement (14) being configured to exploit the electrical conductivity of the liquid to be sprayed.

23. A method of nebulizing liquids in air comprising the steps of: controlling the filling of an intermediate tank (10) from a main tank (1) containing a liquid to be sprayed (36), feeding a nebulization nozzle (30-2) from the intermediate tank, measuring the level of the liquid in the intermediate tank, and controlling the nebulizing nozzle (30-2) during nebulization cycles, to trigger the ejection of liquid droplets into a nebulizing jet, characterized in that it comprises adjustment steps a mean nebulization flow rate to reach an average setpoint flow rate, as a function of the level of the liquid in the intermediate reservoir measured at the end of a nebulization cycle.

24. The method of claim 23, comprising a step of filling the intermediate reservoir (10) with a volume of liquid corresponding to a nebulized liquid volume during a few cycles of nebulization, to reach a reference level slightly lower than a maximum level at beyond which liquid can flow through the nebulizer nozzle (30-2) outside the nebulization cycles.

25. The method of claim 23 or 24, wherein the intermediate reservoir (10) has an interior volume up to the reference level corresponding to the volume of liquid nebulized completely in less than 3 seconds by the nebulization nozzle (30-2). .

26. Method according to one of claims 23 to 25, wherein the intermediate reservoir (10) has an internal volume up to the reference level between 20 and 30 mm3.

27. Method according to one of claims 23 to 26, wherein the reference level above the nebulizing nozzle (30-2) is between 6 and 12 mm.

28. The method according to one of claims 23 to 27, wherein the measurement of the level of the liquid in the intermediate reservoir (10) is operated to control the control device (12) for filling the intermediate tank (10).

29. Method according to one of claims 23 to 28, comprising a step of estimating the level of the liquid in the intermediate reservoir (10) at the end of a nebulization cycle depending on the amount of liquid poured into the reservoir. intermediate (10) to reach the reference level after one or more nebulization cycles.

30. Method according to one of claims 23 to 29, wherein the nebulizing nozzle (30-2) is located at one end of a capillary tube (30-1), the method comprising a step of driving the tube capillary in vibration so that the nebulization nozzle ejects droplets of liquid into a nebulization jet, during each nebulization cycle.

31. Method according to one of claims 23 to 30, wherein the filling of the intermediate tank (10) from the main tank (1) is controlled by a valve actuated by a piezoelectric means

32. Method according to one of claims 23 to 30, wherein the filling of the intermediate tank (10) from the main tank (1) is performed by the projection of droplets (13) of liquid in the intermediate tank.

33. The method of claim 32, wherein the filling of the intermediate tank (10) from the main tank (1) comprises steps of: filling by gravity from the main tank of a cavity (12-1) opening into the intermediate reservoir by at least one nozzle (12-2), application of an excitation signal (Sv2) to a second vibrating member (TPE2), and application of the vibrations generated by the second vibrating member to the liquid contained in the cavity in order to eject liquid droplets through the nozzle into the intermediate reservoir (10).

34. The method of claim 33, wherein the number of nozzles (12-2) supplied by the cavity (12-1) is determined so that the intermediate tank (10) can be filled at least as fast as it is emptied during the nebulization cycles.

35. Method according to one of claims 23 to 34, wherein the liquid level in the intermediate reservoir (10) at the end of a nebulization cycle is determined from a number of liquid droplets introduced into the intermediate reservoir to reach a reference level.

36. Method according to one of claims 23 to 35, wherein the measurement of the liquid level in the intermediate reservoir (10) exploits the electrical conductivity of the liquid to be sprayed.

37. Method according to one of claims 23 to 36, wherein the step of adjusting the average flow is performed by filling the intermediate reservoir (10) with a constant volume of liquid after each nebulization cycle, periodically adjusting the the level of the liquid in the reservoir (10) up to the reference level, by estimating the quantity of liquid thus added.

38. Method according to one of claims 23 to 37, wherein the liquid (36) in the intermediate reservoir (10a, 10b) rises by capillary action in compartments (15-1, 15-2) formed at a distance from the bottom of the intermediate tank.

39. The method of claim 38, wherein the liquid level is measured in a compartment (15-2) in which do not open the filling nozzles (12-2) of the intermediate reservoir (10b).

40. Method according to one of claims 23 to 39, wherein the intermediate tank (10c, 10d) is supplied with liquid to be sprayed by several main tanks (1a-1e) via a control device (12a). -12e) of respective intermediate filling.

41. Process according to claim 40, in which one of the main tanks (1a, 1b) contains a concentrated active product and another one of the main reservoirs a solvent or a mixture of solvents, the concentrated active product being mixed with the solvent or the mixture of solvents in the intermediate reservoir (10c) according to a selected concentration of active product.

42. The method of claim 40, comprising a step of mixing in the intermediate reservoir (10d) of different liquids each from one of the main tanks (1c, 1d, 1e) in selected proportions.

43. The method of claim 42, wherein the liquids contained in the main tanks (1c, 1d, 1e) are perfumes, and each correspond to the base, heart and head of a fragrance obtained in the intermediate tank .