Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B17/00—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups
  • B05B17/04—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods
  • B05B17/06—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations
  • B05B17/0607—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers
  • B05B17/0615—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers spray being produced at the free surface of the liquid or other fluent material in a container and subjected to the vibrations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
  • B05B7/0012—Apparatus for achieving spraying before discharge from the apparatus
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D17/00—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces
  • F25D17/04—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection
  • F25D17/042—Air treating means within refrigerated spaces
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2317/00—Details or arrangements for circulating cooling fluids; Details or arrangements for circulating gas, e.g. air, within refrigerated spaces, not provided for in other groups of this subclass
  • F25D2317/04—Treating air flowing to refrigeration compartments
  • F25D2317/041—Treating air flowing to refrigeration compartments by purification
  • F25D2317/0413—Treating air flowing to refrigeration compartments by purification by humidification

Definitions

• the invention relates to the technical field of spraying devices capable of producing a mist of micro-droplets from a liquid.
• the droplets are generated by a piezoelectric element.
• Numerous devices are known for spraying micro-droplets of a liquid under the effect of ultrasound. Ultrasound is generated by a piezoelectric element. These devices use either a microperforated membrane or a piezoelectric element with or without a concentrating nozzle. The size of the droplets generated by these devices is typically between 1 and 10 ⁇ . Many types of spray devices using a microperforated membrane are known in the literature.
• Such devices are described for example in the documents WO 2013/1 10248 (Nebu Tec), WO 2012/020262 and WO 05/15822 (Technology Partnership), EP 2 244 314 (Zobele Holding), US 2006/213503 and US 2005 / 224076 (Pari Pharma), WO 2001/85240 (Pezzopane), FR 2 929 861 (L'Oreal), US 8 870 090 (Aptar), WO 2008/058941 (Telemaq), JP 2001/300375 (Panasonic). Some of them are very simple and quite compact, but generally devices using a membrane have a very low flow rate, that is to say, they produce a very small amount of fog.
• Spray devices are also known using a vessel provided with a concentrating nozzle and a piezoelectric element, as described for example in EP 0 691 162 A1 and EP 0 782 885 A1 (IMRA Europe). These devices are very reliable and are commonly used to moisten and freshen fresh products on sales stands, as described in documents FR 2 899 135 A1, FR 2 921 551 A1, WO 2014/023907 A1, WO 2013/034847 A1 (ARECO) , FR 2 690 510 A1 (Techsonic). Their flow is important and suitable for many technical and industrial uses; in return, their electrical consumption is significant (of the order of 10 to 70 W per piezoelectric element).
• these devices are not likely to be disturbed in their operation by clogging problems; they have a lifespan of 5000 hours on average.
• these devices have a certain size which is mainly related to the thickness of water necessary for the proper functioning of the piezoelectric element (generally from 20 to 35 mm), to the diameter of the piezoelectric element, and also at the height of the diffusion chamber necessary for the creation of an acoustic jet almost vertical and very powerful (generally from 40 to 100 mm).
• the present invention seeks to solve is to provide a miniaturized spraying device, and in particular of very low height, having a high flow rate, a low power consumption, which is of great reliability that does not need to be used. frequent maintenance, and which presents no risk of clogging.
• a nebulizing device capable of generating a mist of droplets of a liquid from a liquid contained in a tank, said device comprising:
• a piezoelectric element able to emit acoustic waves in said liquid
• the emitting face of said piezoelectric element forms with the surface of said liquid an angle ⁇ of between 60 ° and 95 °, preferably between 70 ° and 95 ° and even more preferably between 75 ° and 90 °,
• said deflector being adapted to orient said jet in a direction substantially opposite to the direction of emission of acoustic waves by the piezoelectric element and towards said fog diffusion system.
• Said acoustic reflection surface advantageously has a substantially parabolic shape.
• Said deflector is advantageously able to orient the jet of liquid generated by the effect of said acoustic waves outside the liquid surface area which extends between the emitting surface of the piezoelectric element and said acoustic reflection surface.
• the primary spray jet has an angle of between 5 ° and 85 ° (and preferably between 10 ° and 60 °) with respect to the surface of the liquid.
• the focal point of the acoustic waves reflected by the acoustic reflection surface is advantageously at a depth of between 0 mm and 5 mm and preferably between 1 mm and 3 mm below the surface of the liquid: this ensures a bin fog yield and good stability of the operating conditions of the device.
• the device according to the invention may comprise a fan which generates an air flow towards said deflection surface.
• the device according to the invention comprises an auxiliary deflector disposed downstream of the primary jet; this auxiliary deflector slows the flow of fog.
• the height h of the liquid in the device does not exceed 12 mm, preferably does not exceed 10 mm, and even more preferably does not exceed 9 mm.
• the device according to the invention comprises means for periodically or permanently disinfecting said liquid, such as a UV light source or a heating resistor.
• the device according to the invention can be constructed in a very compact manner, and in particular with a low height.
• the total height of the device does not exceed 35 mm, preferably does not exceed 30 mm, and even more preferably does not exceed 25 mm.
• the device according to the invention comprises an upper part which integrates in a single piece (for example in the form of a cap or dome) the deflector which directs the jet of liquid generated by the effect of the waves. acoustic, and which also incorporates the auxiliary deflector; these two deflectors may form a single curved surface to the interior of said shell or cupola, which may extend from the air inlet port to the outlet of the fog.
• the device also comprises a lower part which integrates the acoustic reflection surface, and which integrates, at the end opposite to the air inlet orifice, the piezoelectric element; this lower part contains the liquid to be sprayed.
• the device according to the invention can operate with different liquids.
• the liquid may especially be selected from the group consisting of: water, water containing at least one disinfectant product, water containing at least one odorous product, a solution of at least one essential oil, an emulsion of at least one essential oil; or a mixture of the elements that make up this group.
• the device is integrated in a temperature and / or controlled humidity compartment, such as a refrigerator, a cold room, a controlled atmosphere cabinet or a wine cellar.
• the device according to the invention can be integrated into a horizontal plate of a refrigerator, and preferably so that the mist of droplets is introduced into a crisper.
• another object of the invention is a refrigerator plate, comprising a device according to the invention.
• the device according to the invention and in particular the refrigerator plate comprising this device, may comprise a hydraulic adapter capable of accommodating the mouth of a water bottle of the current type.
• Another object of the invention is an apparatus comprising at least one compartment with temperature and / or controlled humidity, such as a refrigerator, characterized in that it is equipped with at least one device according to the invention.
• FIGS 1 to 1 1 show schematically embodiments of the device according to the invention.
• Figure 1 is a block diagram of a device according to the invention shown in vertical section.
• Figure 2 shows three views of a device according to the invention.
• Figure 2c shows the device from above
• Figure 2b shows a front view
• Figure 2a shows a sectional view along the plane A-A shown in Figure 2c.
• Figure 3 shows three further views of the device of Figures 2: a side view in perspective (Figure 3a); a view (Figure 3b) identical to that of Figure 3a but in it shows only the components contained in the housing, the latter (shown in dotted lines) being shown as being transparent; and a view similar to that of Figure 3b but from another angle (Figure 3c).
• Figure 4 shows a perspective view of a section along the plane A-A shown in Figure 2c.
• the circle designates an area "A" which is enlarged in Figure 4b.
• Figure 5 shows another perspective view of a section along the plane AA shown in Figure 2c.
• the circle designates an area "B" which is enlarged in Figure 5b.
• Figure 6 is a block diagram of another device according to the invention shown in vertical section.
• Figure 7 is a block diagram of a device according to the invention which comprises an auxiliary deflector (item 26).
• Figure 8 is a block diagram of a device according to the invention, the deflector has in its lower part a portion with inverse curvature (reference 27).
• FIGS. 9 to 11 show schematically a variant of the embodiment with an auxiliary deflector:
• FIG. 9 is the cross-sectional representation of a nebulization cell according to the invention shown in FIG. 10, whereas FIGS. 1a and 1b show two other views of the same cell.
• the device 1 according to the invention is traversed by an air flow 13 which enters through an air inlet opening 12 advantageously arranged at one of the ends of the device 1, which passes through the nebulizing cell 22 where it is located.
• An embodiment of such a device 1 is shown in Figure 1.
• the mist diffusion system 9 (fogger) is close to the other end of the device 1. It necessarily comprises at least one outlet port 10 through which fog jet 11 emerges in the targeted environment.
• the tank 2 containing the liquid to be sprayed 5 and the nebulization cell 22 with the droplet generator which comprises a piezoelectric element 3 whose active surface is immersed in said liquid 5 to be sprayed.
• the piezoelectric element 3 is arranged so that its active surface is covered at least partially with a liquid thickness sufficient to ensure its cooling.
• said piezoelectric element 3 is arranged so that its active surface forms an angle ⁇ greater than 60 ° and 95 ° with respect to the surface of the liquid, preferably between 70 ° and 95 °, and even more preferably between 75 ° and 90 °.
• a quasi-vertical position of the active surface of the piezoelectric element 3 with respect to the surface 6 of the liquid 5 is preferred.
• the acoustic waves emitted by said piezoelectric element 3 are directed towards the liquid / air interface 6 , preferably via at least one acoustic reflection surface 4.
• a piezoelectric element that can be used in the device according to the invention has a near field (ie a zone from the emitting surface where the wave beam is approximately parallel) of about 10 mm to 30 mm.
• a piezoelectric element with a diameter of 10 mm, which makes it possible to reduce the height h of liquid in the tank to less than 12 mm, ideally between 10 mm and 12 mm.
• the acoustic reflection surface 4 has a shape that makes it possible to focus the acoustic waves. It typically has a cap or cupola shape, and preferably a parabolic shape, the concavity of said reflection surface 4 being turned towards the piezoelectric element 3. It allows the focusing of the acoustic waves on a focal zone (of preferably a focal point) which lies below the surface (liquid / air interface) 6 of the liquid 5, at a depth d of the order of a few millimeters (this parameter is shown in FIG. 7).
• the focal point is at a depth d of between 0 and 5 mm.
• the focal point is at a depth of at least 0.5 mm, and still more preferably at least 1 mm; it gives a good performance while ensuring a good stability of the operating conditions.
• a depth of between 1 mm and 3 mm is globally optimal.
• the focal length F between the focal point and the emitting surface of the piezoelectric element 3 is advantageously between 8 and 28 mm.
• the distance between the emitting surface of the piezoelectric element 3 and the acoustic reflection surface, measured at the level of the surface of the liquid, is advantageously between 10 mm and 30 mm (knowing that £> F); it is located in the near field of said piezoelectric element.
• the frequency is advantageously between 1 MHz and 5 MHz, for example 3 MHz.
• the reflection surface 4 must have a high impedance contrast, which makes it possible to produce a very effective acoustic mirror (i.e. a mirror reflecting almost all of the acoustic energy); it is preferably made of metal.
• the inventors believe that the focusing of the acoustic waves by a reflective surface makes it possible to shorten the path of the ultrasonic waves in the water, which avoids their unnecessary dispersion in the volume of liquid: thus the entire Acoustic energy is used to produce surface waves, allowing to detach micron-sized droplets from the surface with high efficiency.
• a jet of droplets 20 here called "primary jet nebulization"; it is often accompanied at least for part of its length by a jet of water called an acoustic water jet.
• the direction of this primary jet of nebulization 20 is determined mainly by the focusing of the acoustic waves; the direction is expressed here by an angle ⁇ with respect to the surface of the liquid 5 in the opposite direction to the air flow, defined in FIG. 1 (the 0 ° angle corresponding to the horizontal opposite to the flow direction of air F At the angle 180 ° horizontally towards the air flow). It can be adapted to the operation of the device, in particular according to the presence or absence of a fan 23.
• the primary fogging jet 20 is directed in the opposite direction of the air stream 13, or at least in a direction that strikes the latter (preferably with an angle ⁇ less than 90 °, as is represented in FIG. 1), this makes it possible to prevent the larger drops 17 from being carried in the mist 8; they fall back into the tank of the tank 2.
• the separation effect of large drops that has just been described is particularly effective when the air flow F A is generated by a fan. Indeed, in one embodiment of the invention is added to the device 1 according to the invention a fan, preferably installed near the air inlet port 12. Such an embodiment is shown on the Figure 6.
• the acoustic jet is carried by the air flow from the fan; the parabolic shape of the acoustic reflection surface 4 and the shape of the deflector 7 determine a geometry that promotes the blowing of small droplets at the expense of large drops; this enrichment of the mist in small droplets is desirable for the desired result.
• a deflector surface 7 (preferably made of metal to minimize absorption energy loss) against which the primary spray jet 20 encounters after encountering the air stream 13 is very advantageous for separating the droplets.
• the fog 11 delivered by the device 1 be composed of very fine droplets, in order to allow rapid evaporation of the fog once deposited on a solid surface or in a small volume.
• This evaporation ensures rapid cooling of the environment (ie air and the surface on which the fog is deposited) insofar as the enthalpy of evaporation comes from the environment (air and surface on which the fog is deposited).
• the finer the drops the faster their evaporation and the less stagnant moisture (drops of water) will affect the surface or the volume.
• the surface of the deflector 7 of the primary jet nebulization serves as deflector of the jet in order to remove at least a portion of the large droplets 17 and spread the nebulization. At the same time this deflector surface 7 also guides the return of water from the acoustic water jet in a zone away from the focal point so as not to disturb the water jet and to reduce its droplet yield.
• the air flow 13 which passes through the device 1 can also be generated by simple aspiration, the air in the air space below the deflector 7 being driven towards the diffusion system 9 under the effect of the primary jet 20.
• the device 1 according to the invention does not need a fan, the air flow 13 generated by suction being strong enough for certain types of applications; the speed of said "natural" airflow will generally be lower than with fan.
• the inventors believe that this finding is explained by the fact that the initial velocity of the acoustic waves on the surface of the liquid is sufficient to generate droplets with sufficient energy to transfer a portion of them to the molecules of the liquid. surrounding air.
• the direction and the power of the primary fogging jet play an essential role for the proper functioning of the system, this direction being chosen and controlled by means of the acoustic reflection surface 4, its shape is preferably parabolic, and the parabolic equation is selected so as to have a primary jet 20 which makes an angle ⁇ of between 95 ° and 175 ° degrees (and preferably between 100 ° and 150 °) relative to the surface 6 of the liquid.
• a small auxiliary baffle 26 (which may be for example a solid surface or a grid) close to the diffusion outlet to block large parasitic drops; this is shown schematically in FIG. 7.
• the symbol Fij designates the direction of the primary jet of nebulization 20, the symbol F has that of the air flow 13 generated by suction.
• This figure shows an angle ⁇ which corresponds to (180 ° - a).
• the deflector 7 has a dual function. Its shape and positioning must be such that it can properly orient the primary jet of nebulization 20, and such that it can ensure that the jet of liquid called "acoustic", which accompanies the primary jet of nebulization 20, is oriented in an area that does not disturb the focal point 28 of the acoustic waves in the liquid.
• the deflector 7 extends in the upstream direction (ie opposite to the air flow) so as to conduct the jet of acoustic liquid outside the zone that extends between the piezoelectric element 3 and the acoustic reflection surface. 4.
• the device according to the invention comprises an upper portion 29 which integrates in one piece (for example in the form of a cap or dome) the deflector 7 of the primary jet nebulization which directs the jet of liquid generated by the effect of acoustic waves, and which also integrates the auxiliary deflector 26; these two baffles may form a single curved inner surface of said shell or cupola, which may extend from the air inlet port 12 to the outlet 21 of the fog.
• the device also comprises a lower part 30 which integrates the acoustic reflection surface 4, and which integrates, at the end opposite the air inlet port 12, the piezoelectric element 3; this lower part contains the liquid 5 to be sprayed.
• the deflector 7 has in its lower part, near the liquid surface, a portion 27 having a curvature in the opposite direction, to promote the entry of the air flow in the nebulization cell 22. This is shown in Figure 8.
• the nebulizing cell 22 is delimited by the deflector 7 and comprises the acoustic reflection surface 4.
• the device according to the invention can be installed in a compartment with humidity and / or controlled temperature, such as a refrigerator or a wine cellar.
• the device 1 according to the invention is installed in a ventilated cold refrigerator can be provided an air inlet in which is passively blown the air flow generated by the central cooling fan of the refrigerator, or a fan 23 can be added which generates a flow of air, preferably in the same direction as the air flow generated by the central cooling fan of the refrigerator.
• the tank 2 comprises a disinfection system which can notably be:
• UV light source 19 an ultraviolet (UV) light source (the light being represented by the arrows in FIG. 1) able to disinfect the liquid at least partially that it contains; the operation of this UV light source 19 may be permanent or intermittent;
• a heating resistor capable of temporarily heating the water to a temperature sufficient to disinfect it, for example by thermal shock.
• the device 1 can be supplied with water via a hydraulic adapter (anti-drop) 16; the water can come from a water tank 15 integrated in the device 1 (as shown in FIG. 1) or from an appropriate external supply (pipes fed by a remote tank for example).
• a hydraulic adapter anti-drop
• the water can come from a water tank 15 integrated in the device 1 (as shown in FIG. 1) or from an appropriate external supply (pipes fed by a remote tank for example).
• the water level 6 is automatically controlled via a leveled control tube 14 beveled; this increase in the open section of the tube avoids blocking any air bubbles at the entrance.
• This tube is equipped with a hydraulic anti-drip adapter; it is advantageous to choose an adapter model suitable for the majority of commercial water bottles.
• the water supply of the tank 2 can be done in various other ways (not shown in the figures).
• water can come from a remote tank.
• the water that feeds the tank 2 may come from the condensate recovery (a filter is advantageously provided for filtering said condensate before its admission into the tank 2), or the water which feeds the tank 2 can be taken from the water supply of the refrigerator, if the latter has such a power supply.
• the system 1 according to the invention has a small total height y, which may be less than 35 mm, preferably less than 30 mm and even more preferably less than 25 mm. This low height opens up completely new application possibilities.
• the device according to the invention can be installed in the thickness of a horizontal plate 24 of a refrigerator.
• Such plates are usually either glass or plastic, and if they are glass they include a plastic frame; as a result they have a thickness of about 15 to 25 mm at the frame.
• the nebulizing device 1 is integrated in at least one plate of a refrigerator, and the outlet orifices 11 are directed downwards to create a controlled humidity atmosphere.
• said device 1 in the upper wall of the crisper or in a plate inside said tray, and the outlet ports 11 are directed towards the interior of said crisper. This embodiment is shown schematically in FIG.
• Said horizontal plate 24 is preferably removable to be removed from the refrigerator and has for this purpose fastening means 25.
• the operation of the nebulization system according to the invention can be synchronized with the opening of the door of the refrigerator and / or the amount of nebulization injected into the refrigerator volume can be controlled by a humidity sensor (not shown in the figures), with a feedback loop on the nebulizing device.
• a hygrometric probe which measures the humidity level in the volume of air conditioned by the device 1 according to the invention; a feedback loop makes it possible to regulate the intensity and / or the intermittency of the fog jet 11 produced by the device 1 so as to obtain in said volume of conditioned air a controlled humidity level, preferably constant, and of preferably adjustable via an adjusting member.
• said liquid 5 comprises a disinfectant, so that the fog jet 11 is able to disinfect at least partially said volume of air and possibly the walls that confine it.
• said liquid comprises a so-called essential fragrance or oil, or other odorous product, so that the mist jet 11 is able to diffuse into said air volume a specific odor.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Special Spraying Apparatus (AREA)
• Disinfection, Sterilisation Or Deodorisation Of Air (AREA)

Applications Claiming Priority (3)

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• 2014
  • 2014-12-05 FR FR1402792A patent/FR3029431A1/fr active Pending
• 2015
  • 2015-02-24 FR FR1551558A patent/FR3029432B1/fr not_active Expired - Fee Related
  • 2015-11-26 WO PCT/FR2015/053236 patent/WO2016087752A1/fr active Application Filing
  • 2015-11-26 EP EP15808754.4A patent/EP3227622B1/de active Active

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