EP2090187A1 - Spraying head comprising a sonotrode crossed by a channel for carrying the product - Google Patents

Abstract

The head has an aluminum sonotrode i.e. acoustic amplifier, transmitting ultrasonic vibrations from a transducer i.e. generator, towards a product particle ejection surface (4). The sonotrode has a product supply channel supplying a cosmetic or dermatological product e.g. self-tan, towards the ejection surface. The channel has a narrow portion between a product inlet inputting the product in the sonotrode and a product outlet outputting the product towards the ejection surface. The narrow portion is opened on the ejection surface, and has a circular transversal section. Independent claims are also included for the following: (1) a cosmetic product packaging and spraying device comprising a container (2) a cosmetic processing method.

Description

The present invention relates to devices for spraying a product, in particular to spray a product on keratin materials such as human skin or hair.

The invention relates more particularly to a spraying head comprising a sonotrode, also called acoustic amplifier, for transmitting ultrasonic vibrations from a transducer, also called a generator, generating these vibrations to an ejection surface of the product particles.

The sonotrode can be placed in a flow of air intended to convey the product particles on the region to be treated.

Many spray devices with a sonotrode have already been proposed.

For example, the patent US 3,970,250 and European patent applications EP 0 389 665 and EP 1 508 382 A1 disclose spray heads traversed by product feed channels of constant cross section, opening on the end face of an end flange of the sonotrode, this end face defining the ejection surface.

In the patent US 3,970,250 , the sonotrode comprises a frustoconical portion which connects directly to the end collar. The sonotrode is placed inside an air blast nozzle, set back from the opening through which the air exits this nozzle. The sonotrode is fixed at a vibration node of the frustoconical portion. The nozzle has a convergent portion which passes close to the free edge of the collar, which reduces the passage section offered to the air flow and avoids according to this patent the flow of the product on the rear face of the flange.

Requirement EP 0 389 665A1 discloses a shutter arranged to close, in the absence of spraying, the orifice through which a product supply channel opens on the ejection surface. This shutter is controlled by a rod which passes through the sonotrode through the supply channel. Such a device is of relatively complex construction.

In the request EP 1 508 382 A1 , in one example, the end flange is traversed by multiple orifices for the passage of an air flow driving of the product particles. The supply of product is carried out by bringing the product directly on the ejection surface, by a conduit external to the sonotrode.

EP 0 569 611A1 discloses a spraying device having a peristaltic pump for feeding the product onto the ejection surface.

Requirement WO 2007 / 104859A1 discloses a device in which the product is brought into contact with the ejection surface by a capillary wick. The sonotrode comprises an end flange which is connected to a cylindrical portion of revolution. The use of a capillary wick does not allow the spraying of relatively viscous products. The collar does not flex under the effect of vibrations of the sonotrode.

FR 2,747,542 discloses a hair dryer arranged to spray a mist of fine water droplets, to moisten the hair.

FR 2,532,861 discloses an ultrasonic sprayer for operating at a frequency of about 60 kHz, especially for an oil burner. The thickness of the end flange is about 1 mm for a diameter of about 12 mm.

The patent US 4,541,564 discloses a high rate spraying device, equipped with several feed channels. The presence of several channels and the thickness of the end flange, about 3 mm for a diameter of about 5 cm, makes the spraying device relatively bulky.

The publication JP 04 11 0097 describes a complex embodiment head. The head can suffer from a loss of energy, by its construction. In addition, the head retains a certain amount of the product in an internal chamber, which can degrade in the absence of spraying.

• tout d'abord, le spray doit être précis et le plus homogène possible de façon à faciliter l'opération de pulvérisation et permettre le cas échéant un maquillage régulier. En particulier, il peut s'avérer souhaitable que la tache formée par le produit pulvérisé soit sans manque central prononcé, lié à la présence de la sonotrode dans le flux d'air vecteur,
• la granulométrie du spray doit répondre aux normes sanitaires, avec pas ou peu de particules fines.
• le débit de produit doit être suffisant afin de ne pas rendre l'opération de pulvérisation trop longue et inconfortable,
• le dispositif de pulvérisation doit pouvoir s'adapter à des produits ayant des viscosités susceptibles de varier selon les formulations,
• le dispositif doit être ergonomique, avoir une autonomie suffisante, être facile à manipuler et fiable,
• la tête de pulvérisation ne doit pas se boucher facilement et rester aisée à nettoyer, le cas échéant,
• le fonctionnement doit se faire sans encrassement du dispositif par une accumulation excessive et non souhaitée de produit dans une zone du dispositif,
• enfin, le coût du dispositif doit rester compatible avec une large diffusion dans le public.

Spraying a cosmetic product on keratin materials must satisfy a number of constraints:

• firstly, the spray must be precise and as homogeneous as possible so as to facilitate the spraying operation and allow, if necessary, regular makeup. In particular, it may be desirable for the spot formed by the sprayed product to be without a pronounced central deficiency, linked to the presence of the sonotrode in the vector air stream.
• the particle size of the spray must meet sanitary standards, with little or no fine particles.
• the product flow must be sufficient in order not to make the spraying operation too long and uncomfortable,
• the spraying device must be able to adapt to products having viscosities which may vary according to the formulations,
• the device must be ergonomic, have sufficient autonomy, be easy to handle and reliable,
• the spray head should not become clogged easily and remain easy to clean, if necessary,
• the operation must be carried out without clogging of the device by excessive and undesired accumulation of product in an area of the device,
• finally, the cost of the device must remain compatible with wide public dissemination.

The invention aims to further improve the spraying devices for spraying a product, especially on human keratin materials. The object of the invention is, inter alia, to provide a satisfactory performance spray head while being of simple construction.

• une sonotrode pour transmettre des vibrations ultrasonores depuis un transducteur vers une surface d'éjection de particules de produit, la sonotrode comportant un canal d'amenée du produit vers la surface d'éjection,

la tête étant caractérisée par le fait que le canal présente une portion rétrécie entre une entrée du produit dans la sonotrode et la sortie du produit vers la surface d'éjection.According to a first of its aspects, the subject of the invention is a spray head of a cosmetic or dermatological product, in particular a product to be applied to the human body, comprising:

• a sonotrode for transmitting ultrasonic vibrations from a transducer to a product particle ejection surface, the sonotrode having a product delivery channel to the ejection surface,

the head being characterized in that the channel has a narrowed portion between an inlet of the product in the sonotrode and the outlet of the product to the ejection surface.

The narrowed section can slow the flow of the product and improve the performance of the spray. The narrowed portion may in particular allow to obtain a relatively homogeneous spray.

The presence of the narrowed portion facilitates the manufacture of the rest of the channel, which may have a relatively large section, which limits the pressure losses.

The narrowed portion may provide some capillary restraint in the absence of use of the device and reduces the exchanges with the air. The use of a shutter for the supply channel can be avoided.

The sonotrode may include an end flange defining a product particle ejection surface, the flange being adapted to bend under the effect of vibrations of the sonotrode.

The flange can, during oscillations, be deformed by changing the shape of the ejection surface, which can pass for example from plane at rest to concave or convex forward. The forward or backward deflection amplitude may be greater than or equal to 5 μm relative to the rest, being for example between 5 .mu.m and 25 .mu.m relative to the rest, ie a total amplitude of 10 to 50 microns.

The channel may be unique and located in the axis of the sonotrode. This can prevent the presence of double seal as in JP 04 11 0097 . This can also avoid mounting where the product remains trapped around the sonotrode, which avoids energy loss and prevents degradation of product in the absence of operation.

The front surface of the sonotrode can be free and without part of the device facing.

The minimum thickness of the end flange in the particle ejection region of the product is, for example, between 0.4 and 0.6 mm, more preferably 0.45 and 0.55 μm, preferably being 0, 5 mm.

The ejection of the droplets of product can take place all around the circumference of the end flange, which contributes to obtaining a homogeneous spray.

• le ratio diamètre transducteur/ diamètre de la portion cylindrique étant inférieur ou égal à 4,5, mieux à 4, encore mieux 3,7 et de préférence supérieur ou égal à 3, de préférence encore compris entre 3,5 et 3,7,
  et/ou
• le ratio diamètre de la collerette / diamètre de la portion cylindrique étant compris entre 7/6 et 13/4,
  et/ou
• le ratio diamètre de la collerette / épaisseur de la collerette étant compris entre 70/6, par exemple 12, et 130/4, par exemple 32.

The invention further relates, in another of its aspects, to a device for spraying a cosmetic or dermatological product, comprising a sonotrode and a transducer coupled to the sonotrode, the sonotrode having an end flange defining a surface of ejection of the product particles, the sonotrode also comprising a portion of decreasing diameter extended by a cylindrical portion (also called horn) connecting to the end collar,

• the ratio transducer diameter / diameter of the cylindrical portion being less than or equal to 4.5, better still 4, more preferably 3.7 and preferably greater than or equal to 3, more preferably between 3.5 and 3.7,
  and or
• the diameter ratio of the flange / diameter of the cylindrical portion being between 7/6 and 13/4,
  and or
• the ratio of the diameter of the flange / thickness of the flange being between 70/6, for example 12, and 130/4, for example 32.

These geometric characteristics lead to particularly satisfactory results.

The flange may have a larger transverse dimension less than or equal to λ / 4, where λ is the wavelength in the sonotrode material of the ultrasonic wave.

The length of the sonotrode, between the face of the sonotrode in contact with a transducer for vibrating the sonotrode and the ejection surface may be less than or equal to λ, for example of the order of λ / 2.

The invention is applicable to many cosmetic or dermatological products, for example a foundation, a self-tanner, a lotion for the body or face, a product containing a styling agent, a sunscreen product.

By "styling agent" is meant any ingredient of a hair composition, especially any polymer, whose function is to provide cohesion to a set of hair by depositing a material limiting their relative movements.

It is possible to use any styling agent known as such in the field of hair treatments, as well as, of course, mixtures containing several of these agents.

Cationic, anionic, amphoteric and nonionic styling agents are conventionally distinguished.

The styling agent is preferably chosen from silicone or non-silicone polyurethanes, linear sulphonic polyesters, branched block acrylic copolymers and octyl acrylamide / acrylates / butylaminoethyl methacrylate copolymers.

Thus, the particularly preferred styling agents can thus be chosen from the AMPHOMER of NATIONAL STARCH, LUVISET Si Pur from BASF, FIXATE G100 from NOVEON, MEXOMERE PW from CHIMEX, AQ 55S from EASTMAN.

The sprayed product may have a viscosity greater than or equal to 0.1 mPaS, better still greater than or equal to 1 mPaS, better still between 10 mPaS and 500 mPaS, in particular between 20 and 150 mPaS, or even 50 mPaS and 100 mPaS.

The viscosity can be measured in the case of a composition such as an oil, for example, at 25 ° C. with a Haake RS 600 rheometer with imposed constraints marketed by the company Thermo Rhéo equipped with a mobile of cone / plane geometry. type 60/1 ° (60 mm for an angle of 1 °). We impose a stress ramp ranging from 0 to 1000 Pa for 100 seconds. The rheogram representing the evolution of the viscosity is then plotted as a function of the shear rate. The rheogram has a plateau with low values of shear rate (called Newtonian plateau), this plateau corresponds to a stable value of the viscosity which is the viscosity of the composition thus determined.

The viscosity can be measured, in the case of a composition such as a foundation for example, at 25 ° C., with a Rhéomat viscometer 180 equipped with the mobile MK-R2 and measuring cup MB-R2 with a volume 60 ml, at a rotation speed of 200 min-1, the measurement being performed after 10 minutes of rotation (time after which there is a stabilization of the viscosity and the speed of rotation of the mobile).

The sonotrode is coupled to a transducer for transforming electrical energy into ultrasonic vibrations. The resonance frequency of the sonotrode is preferably as close as possible to that of the transducer. Coupling can be effected for example by gluing or screwing.

The product particles are advantageously driven to the region to be treated by a flow of air produced by at least one fan. The air flow is for example between 4 and 7 m3 / h, better between 5.5 and 6.5 m3 / h.

In an exemplary embodiment, the narrowed portion opens on the ejection surface. The narrowed portion may have a constant cross section over a distance of at least 1 mm and less than or equal to 10 mm. The length of the narrowed portion is for example less than or equal to 7 mm, better between 1 mm and 5 mm, being for example 2.5 mm. The narrowed portion may have a constant cross section from the end where it opens on the ejection surface to the opposite end.

The narrowed portion advantageously has a circular cross section, which facilitates its realization.

The channel may have a circular cross section over its entire length.

The channel is advantageously rectilinear, with the same longitudinal axis as the sonotrode. The narrowed portion may have a smaller cross section less than or equal to 0.8 mm ² . The narrowed portion may in particular have a diameter less than or equal to 1 mm, for example between 0.4 mm and 0.8 mm, preferably close to 0.6 mm.

The channel may have a larger cross section greater than or equal to 0.8 mm ² .

The channel may have, outside the narrowed portion, a diameter of between 1 mm and 2 mm, for example close to 1.5 mm, or even greater, especially when the transducer is fixed by bolting on the sonotrode.

The shrunken portion length / total length of the sonotrode canal can be between 0.04 and 0.4.

The ratio at the widest cross-sectional area of the canal / narrowest section of the channel may be between 1 and 25, better still between 4 and 10, for example between 6 and 6.5.

The channel can feed the ejection surface through a single outlet port, which can be located in the center of the ejection surface.

The sonotrode can be made monolithically with a connection piece to a product supply tube of the channel. This feed tube may be a flexible conduit, which allows the use of the conduit within a peristaltic pump. The connection of the channel to the supply duct can still be done differently, for example by means of a nozzle inserted into the sonotrode.

The transducer may be traversed by the tip, having for example an annular shape.

The outer diameter of the end flange is for example between 7 and 13 mm, better 8 and 12 mm, more preferably 9 and 11 mm, preferably close to 10 mm. Good results can be obtained, in an exemplary embodiment, with a diameter of 10 mm for the end flange and a minimum thickness of 0.5 mm for the collar, for a frequency of 100 kHz ± 10%.

The peripheral annular range of the flange where the thickness of the flange is relatively small, especially less than or equal to 0.6 mm, may have a width, measured radially greater than or equal to 0.2 mm, for example 0.2 mm to 2 mm.

The end flange may comprise an annular range 0.5 mm thick which extends over a width, measured radially, of at least 0.5 mm.

The sonotrode may have a portion whose outer cross section decreases toward the ejection surface, in particular a frustoconical portion. The angle at the top of this frustoconical portion may be between 10 ° and 45 °, in particular be 30 °.

The sonotrode may have a cylindrical portion of revolution, as mentioned above. The decreasing outer section portion may be connected to this cylindrical portion of revolution, the cylindrical portion of revolution being intermediate between the decreasing section portion, in particular frustoconical, and the end collar.

The outer diameter of the cylindrical portion of revolution is for example between 4 and 7 mm, in particular may be close to 5.5 mm.

The length of the cylindrical portion of revolution is for example between 3 and 5 mm.

The length of the different portions of the sonotrode is preferably chosen according to the nominal frequency at which the sonotrode is provided to resonate, the ejection surface preferably having to be substantially at a belly of vibrations. The distance between the ejection face and the transducer as well as the diameter of the end flange can depend on the wavelength λ = c / f, where c is the speed of sound in the material at the temperature of use, and f the frequency.

The sonotrode can be machined, preferably being made of metal, in particular aluminum or aluminum alloy, titanium or its alloys, stainless steel, for example 316 stainless steel

The excitation frequency of the transducer is for example between 30 and 200 kHz. For example, the excitation frequency may be of the order of 100 kHz ± 10%.

The average particle size of the spray depends on the frequency and rheological characteristics of the fluid to be sprayed. The average size is, in an exemplary implementation of the invention, between 20 and 25 microns, especially at a frequency of 100 kHz.

The level of fine particles smaller than 10 μm may be less than 10%.

The invention further relates, in another of its aspects, a device for packaging and spraying a cosmetic or dermatological product, comprising a head as defined above.

This device may comprise a container containing the product to be sprayed. This product may be a care or make-up product, especially a foundation or a product comprising a styling agent, a self-tanning agent or a sunscreen composition.

The container may be in the form of a removable cartridge.

The product can be contained in a soft pouch.

The device may comprise a housing with, in particular in the upper part, a housing for receiving the aforementioned cartridge.

The air flow directed to the keratin materials may be heated or cooled as required.

In an exemplary implementation of the invention, the spraying is triggered by an action of the user on a control member such as a push button for example.

1. i) mise en route d'un ventilateur créant un flux d'air d'entraînement des particules de produit,
2. ii) après un retard prédéfini, mise en vibrations de la sonotrode par un transducteur,
3. iii) après un nouveau retard, mise en route d'une pompe alimentant la sonotrode en produit.

Once a spray cycle is triggered, a spray sequence with the following steps can take place:

1. i) starting a fan creating a product particle entrainment air flow,
2. ii) after a predefined delay, vibrating the sonotrode by a transducer,
3. iii) after a new delay, start a pump supplying the sonotrode product.

At the end of the spraying cycle, the stopping of the device may comprise successively the stopping of the pump, the stopping of the transducer, and the stopping of the ventilator.

The invention further relates, in another of its aspects, to a spraying device comprising a nozzle, a support disposed inside the nozzle, a sonotrode coupled to a transducer, fixed by snapping on the support, with interposition. a joint between a shoulder of the support and a shoulder of the sonotrode.

This aspect of the invention facilitates mounting of the sonotrode in the device.

According to another of its aspects, the invention also relates to a spraying device comprising a sonotrode, an annular-shaped transducer coupled to the sonotrode, the latter being made monolithically with a nozzle on which is inserted a tube of supply of product to be sprayed. This aspect of the invention facilitates the construction of the device.

Another subject of the invention, according to another of its aspects, is a cosmetic treatment method, for example skin, especially makeup, or hair treatment, comprising the step of spraying a cosmetic product on the skin. relevant human keratin materials, using a spray head as defined above.

• la figure 1 représente de manière schématique, en élévation, un exemple de dispositif de pulvérisation réalisé conformément à l'invention,
• la figure 2 représente le dispositif de la figure 1 avec la cartouche de produit en place, prêt à pulvériser,
• la figure 3 représente le dispositif de la figure 1 avec la trappe d'accès au logement de réception de la cartouche ouverte, en attente de la mise en place de la cartouche sur le boîtier,
• la figure 4 est une vue schématique et partielle, en perspective éclatée, du dispositif des figures 1 à 3,
• la figure 5 représente en perspective, de manière schématique et partielle, l'ensemble de pulvérisation,
• la figure 6 est une coupe longitudinale, schématique et partielle, de l'ensemble de pulvérisation de la figure 5,
• la figure 7 représente isolément le support du transducteur,
• la figure 8 représente isolément, en perspective, la sonotrode,
• la figure 9 est une vue en élévation de la sonotrode,
• la figure 10 est une coupe longitudinale de la sonotrode, selon X-X de la figure 9,
• la figure 11 représente en perspective une variante de réalisation de la sonotrode,
• la figure 12 est une coupe longitudinale schématique et partielle d'une tête de pulvérisation comportant la sonotrode de la figure 11, et
• la figure 13 représente de manière schématique, en perspective, la résistance chauffante du dispositif de chauffage.

The invention will be better understood on reading the following detailed description, non-limiting examples of implementation thereof, and on examining the appended drawing, in which:

• the figure 1 shows schematically, in elevation, an example of a spraying device produced according to the invention,
• the figure 2 represents the device of the figure 1 with the product cartridge in place, ready to spray,
• the figure 3 represents the device of the figure 1 with the access door to the receiving slot of the open cartridge, waiting for the cartridge to be placed on the housing,
• the figure 4 is a schematic and partial view, exploded perspective, of the device of Figures 1 to 3 ,
• the figure 5 represents in perspective, schematically and partially, the spray assembly,
• the figure 6 is a longitudinal section, schematic and partial, of the spray assembly of the figure 5 ,
• the figure 7 represents in isolation the support of the transducer,
• the figure 8 represents in isolation, in perspective, the sonotrode,
• the figure 9 is an elevational view of the sonotrode,
• the figure 10 is a longitudinal section of the sonotrode, according to XX of the figure 9 ,
• the figure 11 represents in perspective an alternative embodiment of the sonotrode,
• the figure 12 is a schematic and partial longitudinal section of a spray head comprising the sonotrode of the figure 11 , and
• the figure 13 schematically represents, in perspective, the heating resistance of the heating device.

The spraying device 1 shown in the Figures 1 to 3 comprises a box 2 that can be manipulated by the user to spray a product on the skin or other human keratin materials, such as the lips or the hair.

The housing 2 carries in the rear, in this example, a push button 3 which allows the user, by pressing on it, to trigger the spraying. This push button 3 could alternatively be located elsewhere and replaced by a trigger or a touch sensor, for example.

The device 1 comprises at the front, as can be seen on the figure 2 in particular, a surface 4 for ejecting the product particles. This surface can be oriented to the region to be treated, during use, so as to allow the product particles to be deposited on this region.

The housing 2 comprises in the example in question a protective cover 12 which can be folded down in front of the ejection surface 4 in the absence of use. This cover 12 is for example articulated on the body of the housing, between a lowered position where it covers the ejection surface 4 and a raised position. In an alternative embodiment, the housing is devoid of a protective cover or the latter is mounted otherwise in the housing.

The cover 12 may extend in the continuity of the outer surface of the housing 2, in the folded position.

The housing 2 can accommodate a cartridge 15 containing the product to be sprayed, this cartridge 15 being introduced into a housing 17 of the housing 2.

As can be seen at figure 3 , this housing 17 can be closed in the absence of use by a shutter 18.

In the example illustrated, the housing 17 is open upwards.

The shutter 18 can be slidably mounted on the housing 2. In variants not shown, the housing 17 is disposed otherwise on the housing.

The product contained in the cartridge 15 is for example a foundation, a self-tanner, a lotion for the body or face or a product containing a styling agent.

The capacity of the cartridge is for example between 1 ml and 100 ml, better still between 5 ml and 20 ml, in particular 10 ml.

In a variant not shown, the device 1 can receive several cartridges containing different products or a cartridge containing several products, with a means for selecting the product to be sprayed, or alternatively a means for adjusting the proportion of a product relative to to each other in the spray mixture. Where appropriate, the same cartridge may contain several products with a means of selecting the product to be sprayed or adjusting the proportion of different products in the spray mixture.

The housing 2 comprises at the front, in this example, a general on / off switch 22 and an indicator 23 serving as an operating indicator. The casing 2 comprises, on the sides, air intake openings 30.

We can see on the figure 4 that the body of the housing 2 can be formed by the assembly of two-half-shells 2a and 2b. The latter are for example mounted with a tight fit, possibly reversible, being for example snapped onto one another and / or held by screws. These half-shells 2a and 2b are for example made by molding a thermoplastic material.

The cartridge 15 may comprise two half-shells 15a and 15b which are gathered around a flexible bag 35 containing the product to be sprayed. This pocket 35 is for example heat-sealed on a connecting piece 38 intended to be engaged on a suction nozzle 40 present in the housing 17. In such a case, these tips can be associated so as to define a reversible connection, by example of the male / female type.

The use of a flexible bag 35 allows product removal without air intake in the pocket. Alternatively, the cartridge may contain a reservoir other than a flexible bag, for example a tank with a moving bottom.

The cartridge may comprise, in an implementation variant, a visual indicator of the degree of emptying, for example a transparent window made in one of the half-shells 15a and 15b and / or in the flexible bag 35.

The half-shells 15a and 15b are for example mounted with a tight fit, possibly reversible, being for example snapped and / or glued to one another or fixed otherwise, being for example made of a thermoplastic material, opaque or transparent .

The arrangement of the removable cartridge 15 in the upper part of the device allows to benefit from a gravity effect for the supply of the product.

If necessary, a cartridge of a cleaning product may be used instead of a usual cartridge, to clean the device, in particular the sonotrode and the ejection surface.

The device may be provided to the user, for example within a common package, with one or more cartridges containing one or more products to be sprayed and the cleaning cartridge above.

The cleaning cartridge can be rechargeable or not.

The cleaning solution may be chosen from one of the solvents of the cosmetic composition to be compatible with it, and may comprise, for example, isododecane, a volatile silicone or else alcohol or water.

The device may include, where appropriate, a cartridge recognition system, for example by means of an electromechanical probe, electrical contacts or an RFID chip.

The knowledge by the device 1 of the contents of the cartridge in place can make it possible to automatically adapt operating parameters to the device of the product to be sprayed, for example the product flow rate, the excitation frequency, the air flow and / or the air temperature if any.

The housing 2 houses a source of electrical energy 43, for example one or more accumulators or batteries, and a printed circuit 45 carrying the electronic components of the device 1. These components provide the generation of the voltage required for the spraying, the control of the different electrical elements and can perform ancillary functions such as for example the calculation of the amount of product remaining to be sprayed, to signal to the user the need to replace the cartridge.

The opening of the housing 2 by separation of the half-shells 2a and 2b may be necessary to replace the batteries. Alternatively, access to the battery compartment can be do without opening the housing, thanks to an access hatch to this compartment. The spraying device 1 may comprise, if necessary, an electrical connector for recharging an accumulator present in the housing.

The housing 2 also houses a set (also called spray head) 50 and a pump 53, the latter being connected on the one hand to the suction nozzle 40 and on the other hand to the spray assembly 50 by a tube 55, which is preferably a flexible conduit.

The pump 53 is for example of the peristaltic type, comprising an electric motor 57 rotating one or more rollers bearing on the flexible conduit 55 to push the product to the spray assembly 50. The product flow during operation of the pump 53 goes for example from 0.05 g / min to 2 g / min.

In this case, the flow can be adjustable by the user with certain preset values.

In variants not shown, other types of pumps are used, for example gear, diaphragm or piston. A gravity feed or retractable elastic bag can still be considered.

The spray assembly 50 has, at the rear, a fan 60, as can be seen in FIG. figure 4 this fan 60 has not been shown on the figure 5 for the sake of clarity of the drawing.

The spray assembly 50 also comprises a nozzle 65 comprising a tubular body, closed at the rear by a plug 70 provided with openings 71 for the passage of the air blown by the fan 60.

The fan 60 is for example fixed on the plug 70, for example by screws.

The axis of rotation of the fan is for example merged with the longitudinal axis of the nozzle 65.

The air flow injected into the nozzle 65 by the fan 60 is, for example, between 4 and 7 m 3 / h.

The air is sucked by the fan 60 outside the housing 2 through the gills 30.

The fan 60 can operate continuously as soon as the user has switched on the device by means of the main switch 22 or, alternatively, only when the user triggers the spraying, by pressing the push-button 3. In one example, the operation of the fan may be prolonged after the end of the spraying for a predefined duration or until a new action of the user on the device, so to allow the user to take advantage of the air to accelerate the drying of the product deposited on the region to be treated.

Still in an exemplary implementation of the invention, a spraying cycle controlled by an action on the push button 3 comprises first of all the startup of the fan, then after a delay of between 300 and 800 ms per minute. For example, about 500 ms, the spray head is excited, then after a new delay, for example between 300 and 800 ms, in particular of the order of 500 ms, the pump 53 is turned on. The stop of the spraying is carried out when the push-button 3 is released, the above steps succeeding one another in the reverse order.

The device 1 advantageously comprises a means 200 for heating the air blown towards the surface on which the spray is sprayed. This speeds up the drying of the product and the device is thus more comfortable to use. It can also heat up the sonotrode and reduce the viscosity of the product, facilitating its flow and spraying.

The heating means 200 comprises, for example, an electric heating resistor 210 which can be integrated in the fan 60 or placed upstream or downstream of the fan, preferably upstream, as illustrated in FIG. figure 6 .

The heating means 200 is for example fixed to the fan 60.

In one example, the heating resistor 210 consists of a Nichrome wire 0.51 mm in diameter and 2.8 m in length, wound in the form of a spring as illustrated in FIG. figure 13 , placed behind the fan 60, and fed with a power of 36 W. Such a heating resistor makes it possible to produce a flow of air at a temperature of 36 ° C. to 10 cm from the product ejection surface.

The nozzle 65, the fan 60 and the heating means 200 can be, even before their assembly in the housing 2, integral with each other. Thus, these elements can be a one-piece assembly easy to mount in the housing 2. Such elements can be arranged aligned one behind the other. The alignment of these elements makes the device relatively compact.

The temperature at which the hot air leaves the nozzle 65 is for example between 30 and 40 ° C, ideally about 37 ° C.

The air outlet temperature can be regulated, if necessary, by the presence of a temperature sensor exposed to the hot air flow and an electronic control loop.

The device can be arranged to allow the user to choose between an operation where the air blown by the device is heated and an operation where it is not.

This choice can be made for example by a selector actuated by the user, this selector being for example controlled by a greater or lesser pressure on the push button triggering the spray.

For example, a moderate pressure on the pushbutton 3 triggers the air-blast spraying at room temperature and a higher pressure triggers the hot-air spraying.

The heater may turn on at the same time as the fan is turned on and off at the same time, or the respective starts may be delayed in time.

The spraying device 1 can be arranged to go into a standby mode in the absence of actuation of the push button 3 for a predefined duration. The return to normal operation of the device may then require pressing the push button 3 or the actuation of the main switch 22.

The body of the nozzle 65 is provided with a lateral opening 75 for the passage of the product supply tube 55, and houses a support 78 which holds a piezoelectric transducer 80.

The latter is mechanically coupled to a sonotrode 82 for amplifying the electromechanical vibrations of the transducer 80, which are radial or longitudinal, to transmit them to the ejection surface 4, the latter being defined by an end flange of the sonotrode 82.

In the example, it is machined aluminum but other materials, including other metals or alloys can be used.

The rear face of the sonotrode 82 is glued to the transducer 80 but the attachment could still be done differently, in particular by mechanical means such as screwing.

The body of the nozzle 65 is for example cylindrical of revolution and may be molded in a thermoplastic material.

The nozzle 65 may have, at the front, a convergent portion 85, terminating in an opening 90 having the same axis X as that of the sonotrode 82. This opening 90 is circular in the example under consideration, with a diameter of between 14 and 20 mm, for example of the order of 16 mm.

The convergent portion 85 projects into a recess 91 of the housing 2, formed by the assembly of the half-shells 2a and 2b, the bottom of this recess 98 defining an opening 97 which can locally marry the outer section of the nozzle 65.

In the example shown, the flow of air blown by the nozzle 65 is not deflected by the rest of the housing, the recess 91 being sufficiently wide.

The air blown by the fan 60 leaves through the opening 90 in a flow of air generally directed along the axis X.

As can be seen on the figure 6 in particular, the ejection surface 4 protrudes from the plane P of the opening 90 by a distance d. The plane P of the opening 90 is perpendicular to the axis X.

The distance d is for example between 2 and 4 mm, better 2 to 3 mm, even better 2.2 and 2.9 mm, especially for a diameter of the aperture 90 of about 16 mm. Such values make it possible to obtain a relatively homogeneous spray with few losses at 5 or 10 cm away from the ejection surface 4.

A distance d out of the range above can lead to a less good homogeneity of the spray, with for example a central lack and / or a less precise product spot.

The support 78, which is for example molded in one piece of a thermoplastic material, comprises a portion 92 provided to force-fit into the central lumen 72 of the stopper 70, up to the stop of a shoulder 93 of the support 78 against the inner face 94 of the cap 70.

The support 78 comprises, opposite the mounting portion 92, tabs 100 which are elastically deformable, for example four in number, each provided with a tooth 101 at their end, which allows snap-fastening of the sonotrode 82 and of the transducer 80, as illustrated in figures 5 and 6 .

The support 78, in addition to maintaining the sonotrode, can also contribute to a good distribution of the air flow inside the nozzle 65, all around the sonotrode 82.

The transducer 80, which has an annular shape, is in the example considered sandwiched between on the one hand an O-ring 101 and on the other hand the rear face 112 of the sonotrode.

A recess 114 is formed in the rear face 112 for the passage of a first electrical supply wire of the sonotrode, contacting the transducer face adjacent to the sonotrode 82. The other face is electrically connected to a second wire. food.

Apart from the recess 114, the sonotrode 82 is in the example considered symmetrical of revolution about the axis X.

Different transducers can be used. A transducer 80 comprising a piezoelectric ceramic that is suitable for the invention is, for example, that marketed by Ferroperm under the reference 26132. It is a piezoelectric ceramic PZ26 in the form of a ring with an outside diameter of 20 mm, inside diameter 3, 8mm and 2mm thick.

The O-ring 110 rests on a shoulder 116 of the support 78, as can be seen in FIG. figure 6 and the transducer 80 is supported by its face opposite the sonotrode 82 on the seal 110, near its radially outer edge.

The seal 110 allows play-free mounting of the sonotrode 82 and the transducer 80 on the support 78.

The sonotrode 82 comprises, at the rear, a first enlarged cylindrical section 120, defining a shoulder 125 on which the teeth 101 can catch.

The sonotrode 82 extends forward, beyond the shoulder 125, by a frustoconical portion 130 which is connected, by a fillet 131, to a second cylindrical section 132, of axis X. This cylindrical section 132 is connected by a fillet 134 to an end flange 140 whose front face, generally perpendicular to the axis X, defines the ejection surface 4 of the product.

The diameter D of the first cylindrical section 120 is for example between 18 and 22 mm, and is for example 20 mm. This diameter D corresponds for example substantially in the larger diameter of the transducer 80. In a variant, the transducer 80 has a diameter of 15 mm.

The length of the cylindrical section 120 is for example between 1.5 and 5.5 mm, and is for example 3.5 mm.

The largest diameter D2 of the frustoconical portion 130 is for example between 15.5 mm and 19.5 mm and is for example 17.5 mm and the smallest diameter D3 of the frustoconical portion 130 is for example between 8 and 12 mm, and is for example 10 mm. The angle α at the top of the frustoconical portion 130 is 30 ° in the illustrated example.

The radius of curvature of the fillet 131 is for example between 2 and 3 mm and is 2.5 mm in the example shown and that of the fillet 134 is for example between 1 and 2 mm and is 1.5 mm in the illustrated example.

The distance 11 between the shoulder 125 and the ejection surface 4, measured along the X axis, is for example between 13 and 17 mm and is for example 14.9 mm in the illustrated example.

The distance 12 between the top of the frustoconical portion 130 and the ejection surface 4 is for example between 7 and 10 mm and is 8.4 mm in the illustrated example.

The distance 13 between the rear end of the second cylindrical section 132 and the ejection surface 4 is for example between 4 and 8 mm and is 5.9 mm in the illustrated example.

The distance 14 between the front end of the second cylindrical section 132 and the ejection surface 4 is for example between 1.5 mm and 2.5 mm and is 2 mm in the example shown.

The diameter D1 of the second cylindrical section 132 is for example between 4 and 6 mm and is 5.5 mm in the example shown and the thickness e of the end flange 140, measured along the X axis in the vicinity of its radially outer edge, is for example between 0.4 and 0.6 mm and is 0.5 mm in the example shown.

The diameter D7 of the end flange is for example between 7 and 13mm, being 10 mm in the example in question.

The rear face of the end flange 140 ends, in the example under consideration, perpendicularly to the axis X.

The thickness of the flange can be constant from its periphery over an annular range of width Δr, measured radially, between 0.2 and 2 mm, being 0.5 mm in the condidéré example.

The ratio D7 / D1 is for example between 7/6 and 13/4 and the ratio D7 / e between 70/6 and 130/4.

The invention is not limited to the end flange shape exemplified in the drawing and other forms are possible, for example an elliptical shape. In this case, the term "diameter" refers to that of the circle circumscribed to the collar.

The sonotrode 82 is made in the example under consideration with, at the rear, a tip 150 for connection to the supply duct 55, the end piece 150 being for example monolithic, made by machining with the rest of the sonotrode 82. tube 55 is for example force-fitted on the endpiece 150.

A product supply channel 160 passes through the sonotrode 82 along the X axis. A first portion 160a of the channel 160 extends with a constant inside diameter, from the lower end 162 of the endpiece 150 to a point 165 located in the second cylindrical section 132, where this portion 160a it is connected to a narrowed portion 160b by a frustoconical bore 160c.

The inner diameter D5 of the channel 160, on its portion 160a of larger diameter, is for example between 1 and 3 mm and is 1.5 mm in the example shown, and the diameter D6 of the tapered portion 160b is for example between 0.4 mm and 0.8 mm and is preferably 0.6 mm.

The presence of the portion 160a of larger diameter facilitates the machining of the channel 160 and makes it possible not to generate an excessive pressure drop. The presence of the narrowed portion 160b leads to superior performance in the quality of the spray formed.

The length 17 of the narrowed portion 160b, measured along the X axis, is for example between 2 and 3 mm and is for example 5 mm.

The transducer 80 is excited for example at a frequency between 30 and 200 kHz, better 60 and 200 kHz, and the pump 53 delivers to the ejection surface 4, through the channel 160 passing through the sonotrode 80, the product to spray.

The excitation frequency of the transducer 80 may be constant, or better, servocontrolled so as to obtain the maximum amplitude of vibration of the ejection surface and spray efficiency.

The electronic components of the device may comprise an electronic circuit performing this function in a conventional manner.

The operation of the pump 53 may include, where appropriate, at the end of the spraying, a reversal of the direction of rotation of the engine for a short time, in order to suck up the product present in the channel and reduce the risk of drying and drying. clogging of the canal.

When a voltage is applied to the transducer 80 by means of these first and second supply wires, the transducer 80 vibrates in the example considered radially with respect to the axis X. The vibrations thus generated propagate with a amplification of the amplitude in the sonotrode 82 to the ejection surface 4, which vibrates axially by bending.

Under the effect of vibrations, the end flange 140 is deformed, and the oscillations of the flange 140 cause the ejection of product droplets over its entire circumference.

The average size of the emitted droplets is for example between 20 and 30 microns.

The ejected product droplets are entrained by the flow of air leaving the opening 90 towards the surface to be treated, and reaching this surface in the form of droplets.

The product flow rate is for example between 0.5 g / min and 10 g / min depending on the viscosity of the product to be sprayed.

A device according to the invention can make it possible to form, in one example, a product spot of about 40 mm, solid and homogeneous, on the region to be treated.

In the example of the figure 10 the particular values of the sonotrode dimensions were given for a frequency f of 100 kHz;

For a different frequency f, the dimensions can be modified by a factor f / f ', as a first approach.

We have shown figure 11 an alternative embodiment of the sonotrode, designed to operate at a frequency of 60 kHz. This sonotrode differs from that illustrated at figure 10 by its dimensions and by the shape of the body 290 located behind the cylindrical portion 132.

The sonotrode comprises an internal thread 220 which allows the attachment of a bolt 250 for holding a vibration generator, composed for example of two piezoelectric ceramics 280 mounted head to tail.

The length 17 of the narrowed portion 160c is for example 3.5 mm. The length of the cylindrical surface 225 from the opposite end face to the collar 140 to a shoulder 226 of the body 290 is, for example, 18 mm, and the distance from the shoulder 226 to the base 295 of a frustoconical portion 227 adjacent to the cylindrical portion 132 is for example 7 mm.

The housing 229 receiving the bolt 250 communicates with two successive bores 230 and 231 of respective decreasing diameters, for example respectively equal to 4 and 2.5 mm.

The bolt 250 is traversed by a central lumen making it possible to bring the product to be sprayed and may comprise a tip 300 for connecting the hose 55.

Of course, the invention is not limited to the embodiments which have just been described.

In a non-illustrated variant, the product feed is carried out by a needle which delivers the product directly inside the sonotrode, set back from the outlet of the product.

The narrowed portion of the channel may be formed not by a machining of the sonotrode but by reporting thereon a flow reducer, such as for example a small sleeve inserted by force into a channel of suitable diameter of the sonotrode.

The device housing 1 can be given other shapes, in particular a pen shape.

The housing handled by the user can be connected, if necessary, by an electric cable to a base comprising at least the power supply.

In a variant not shown, the supply channel opens through several orifices on the ejection surface. These orifices are for example arranged in an axial symmetry. The narrowed portion of the channel may be upstream of the channels communicating with the orifices or alternatively each branch of the channel leading to an orifice has a narrowed portion.

The ejection surface of the sonotrode may have received a surface treatment intended for example to reduce the surface tension. It may be for example a PTFE deposit or a mirror polish.

If necessary, the device may be arranged to allow adjustment of the edge d of the ejection surface 4 relative to the opening 90. This may improve the focusing of the spray.

Alternatively, the device may be used to spray a product into the atmosphere.

The expression "having one" shall be understood as being synonymous with "having at least one", unless the opposite is specified.

Value ranges must be inclusive, unless otherwise specified.

Claims (15)

Spray head of a cosmetic or dermatological product, in particular a product to be applied to the human body, comprising: a sonotrode (82) for transmitting ultrasonic vibrations from a transducer (80) to an ejection surface (4) of product particles, the sonotrode comprising a channel (160) for feeding the product to the ejection surface (4) the head being characterized in that the channel has a narrowed portion (160b) between an inlet of the product in the sonotrode and the outlet of the product to the ejection surface. Head according to claim 1, the channel (160) being single and extending in the axis of the sonotrode. Head according to claim 1 or 2, the narrowed portion (160b) opening on the ejection surface (4). Head according to one of claims 1 to 3, the narrowed portion having a constant cross section over a distance ( ₁₇ ) of at least 1 mm. Head according to the preceding claim, the narrowed portion having a constant cross section over a distance of less than or equal to 5 mm. Head according to any of the preceding claims, the narrowed portion (160b) having a circular cross section. Head according to claim 6, the narrowed portion (160b) having a diameter of between 0.4 and 0.8 mm. A head according to any one of the preceding claims, the narrowed portion (160b) having a smaller cross section less than or equal to 0.8 mm ² . Head according to any one of the preceding claims, the channel (160) having, outside the narrowed portion, a diameter of between 1 and 2 mm. A head according to any one of the preceding claims, wherein the shrunken portion length ratio ( ₁₇ ) / total length of the sonotrode ( ₁₀ + ₁ ) is between 0.04 and 0.4. Head according to any one of the preceding claims, wherein the widest cross-sectional ratio of the narrowest channel / section of the channel is between 1 and 25. Head according to any one of the preceding claims, the sonotrode (82) being made monolithically with a connector (150) for connection to a product supply tube (55) of the channel, the transducer (80) being traversed by the tip (150). Head according to any one of the preceding claims, the ejection surface being defined by the end face of an end flange (140). Head according to any one of the preceding claims, the sonotrode (82) having a portion (130) whose external cross section decreases in the direction of the ejection surface, in particular a frustoconical portion (130), the apex angle ( α) of the frustoconical portion (130) being between 15 and 45 °, in particular 30 °. A device for packaging and spraying a cosmetic product, comprising a head as defined in any one of the preceding claims and a container (15) containing the product to be sprayed, the product being a makeup product, in particular a base of dyed, a self-tanner, a sunscreen product or a product comprising a styling agent.

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