FR3040897A1 - LIQUID ATOMIZER COMPRISING A PIEZOELECTRIC ELEMENT AND IRON, COMPRISING SUCH AN ATOMIZER - Google Patents

Abstract

Liquid atomiser (6) comprising a piezoelectric element (8) fixed on a vibratory displacement amplifying tube (9) comprising a cavity (90) containing the liquid to be atomized, said horn (9) comprising a first part (92) receiving the piezoelectric element (8) and a second part (93), distinct from the first part (92), mechanically and acoustically coupled to a micro-perforated membrane (91) closing one side of said cavity (90), characterized in that said cavity (90) is supplied with liquid from a reservoir (5) by means of a pump (51) having a flow rate greater than the atomizer spray rate (6) in operation and in that said horn (9) has at least one outlet hole (94) connecting the cavity (90) to a bypass pipe (66) to the tank (5).

Description

LIQUID ATOMIZER COMPRISING A PIEZOELECTRIC ELEMENT AND IRON WITH IRON COMPRISING SUCH

ATOMIZER

The present invention relates to a liquid atomizer comprising a piezoelectric element fixed on a vibratory displacement amplification tube comprising a cavity containing the liquid to be atomized and relates more particularly to an atomizer in which the horn is mechanically and acoustically coupled to a membrane micro-perforated closing one side of the cavity.

It is known, from the patent application FR2908329, an ultrasonic liquid atomizer comprising a piezoelectric element fixed on a vibratory amplification amplifying vibrator comprising an end coupled to a micro-perforated membrane closing a cavity formed inside the trunk containing the liquid to be atomized

Such an atomizer has the advantage of vibrating in a longitudinal mode and to allow the instantaneous spraying of a quantity of liquid very accurately with drops of regular size. In addition, the limited height of water above the membrane and the presence of an airtight tank make it possible to avoid the problems of dripping through the membrane when the atomizer is at a standstill.

However, such a liquid atomizer has the disadvantage of not being able to operate for a long time because of the limited capacity of the water tank. However, it is not possible to simply increase the volume of the tank above the micro-perforated membrane because such an increase in volume would cause an increase in the height of the water column above the membrane that would generate undesired water droplet flow through the membrane when the atomizer is stopped.

Also, an object of the present invention is to provide a liquid atomizer, comprising a vibratory displacement amplifying probe comprising a cavity containing the liquid to be atomized closed by a micro-perforated membrane, which can operate for a long time, or even continuously , and which does not present a problem of dripping when the atomization is stopped. Another object of the present invention is to provide an iron equipped with such an atomizer. For this purpose, the subject of the invention is a liquid atomiser comprising a piezoelectric element fixed on a vibratory displacement amplifying probe comprising a cavity containing the liquid to be atomized, the trunk comprising a first part receiving the piezoelectric element and a second part , distinct from the first part, mechanically and acoustically coupled to a micro-perforated membrane closing one side of the cavity, characterized in that the cavity is fed with liquid from a reservoir with a flow rate greater than the spray rate of the atomizer in operation and in that the horn comprises at least one outlet hole connecting the cavity to a bypass duct to the tank.

Preferably, the exit hole will be sufficiently distant from the first part receiving the piezoelectric element not to disturb too much the vibratory operation of the atomizer. The exit hole will also be advantageously sufficiently far from the micro-perforated membrane so that the flow of liquid through the exit hole does not come to disturb the operation of the micro-perforated membrane.

Such an atomizer has the advantage of having a micro-perforated membrane fixed on a part of the vibrating horn in a longitudinal mode, which makes it possible to produce an aerosol with very little dispersion in the diameter of the microdroplets.

According to another characteristic of the invention, the cavity is fed with liquid from the reservoir by means of a pump operating continuously during the liquid atomization phases by the atomizer.

Such continuous operation of the pump has the advantage of cleaning the upper surface of the membrane and preventing the deposition of undesirable particles.

According to yet another characteristic of the invention, the pump also operates, punctually or continuously, outside the liquid atomization phases by the atomizer.

According to another characteristic of the invention, the piezoelectric atomiser vibrates in a longitudinal mode in the range 50 kHz to 200 kHz.

According to another characteristic of the invention, the horn has a sectional variation between the first portion supporting the piezoelectric element and the second portion coupled to the micro-perforated membrane.

Such a section variation has the advantage of amplifying the longitudinal ultrasonic waves emitted by the piezoelectric element and makes it possible to have a level of amplitude such that the scale that can be deposited on the micro-perforated membrane is eliminated.

According to another characteristic of the invention, the micro-perforated membrane is attached to a longitudinal end of the horn.

According to another characteristic of the invention, the trunk has an axis of revolution and comprises at least two exit holes arranged symmetrically with respect to the axis of revolution, the outlet holes communicating with an evacuation chamber connected to the duct. diversion to the reservoir.

Such an arrangement of the exit holes has the advantage of not disturbing the vibratory mode of the horn and makes it possible to obtain a vibration mode of the horn adapted to obtain the spraying of micro-droplets having a mono median diameter. -dispersed centered in a range of between 20 pm and 100 pm.

According to another characteristic of the invention, the micro-perforated membrane is coupled to one end of a cylindrical body of the horn, the outlet holes being formed on the cylindrical body.

According to another characteristic of the invention, the micro-perforated membrane is made of electro-formed stainless steel and is covered with a non-stick coating. By non-stick coating is meant a coating on which a drop of liquid makes a contact angle greater than 90 °. Such an anti-adherent coating makes it possible to limit the adhesion of scale on the membrane.

According to yet another characteristic of the invention, the micro-perforated membrane has holes having a diameter of less than 40 μm, the holes being spaced from each other by more than 400 μm. Such a construction makes it possible to reduce the problem of dripping through the membrane.

According to yet another characteristic of the invention, the outlet hole or holes are remote from the micro-perforated membrane with a height h of less than 10 mm and preferably of the order of 2 mm.

Such a feature makes it possible to eliminate the problems of dripping and to obtain optimized operation of the atomizer during the start and stop phases.

According to another characteristic of the invention, the outlet hole or holes have a diameter greater than or equal to 2 mm.

According to another characteristic of the invention, the atomizer comprises a feed chamber communicating on the one hand with the cavity and on the other hand with a water inlet duct connected to the pump, the feed chamber having an air inlet.

According to another characteristic of the invention, the air inlet orifice comprises a filtration device preventing the intrusion of a foreign body into the feed chamber.

According to yet another characteristic of the invention, the cavity is fed with liquid from the reservoir by a feed circuit comprising a water filter and a device for dispensing an antibiotic product, such as colloidal silver. Such a characteristic makes it possible to avoid the development of algae in the cavity. The invention also relates to an iron having a heating soleplate surmounted by a housing enclosing a reservoir and comprising a liquid atomizer as previously described.

According to another characteristic of the invention, the atomizer is carried by the housing of the iron and moistens a treatment zone located outside the sole.

According to another characteristic of the invention, the atomizer sprays water with a flow rate of between 6 and 20 g / min and preferably of the order of 9 g / min.

Such a characteristic makes it possible to obtain efficient humidification for de-creasing the laundry without this being too important so as not to create difficulties in drying the laundry during a passage of the soleplate of the iron.

According to yet another characteristic of the invention, the atomizer diffuses a mist of micro-droplets whose median mono-dispersed diameter is between 30 μm and 60 μm.

Such a characteristic makes it possible to obtain a fog which at the same time does not fly off too much and does not make water stains on the clothes to be ironed.

According to yet another characteristic of the invention, the atomizer has a diffusion spectrum adapted to humidify a treatment zone extending along the two edges of a front tip of the sole.

Such a feature allows, with a single atomizer, to moisten the laundry located on both sides of the front tip of the sole.

According to yet another characteristic of the invention, the holes of the micro-perforated membrane are distributed in a V-shape.

Such a characteristic makes it possible to obtain a scattering spectrum of the microdroplets conforming to the V shape of the front tip of the sole.

The aims, aspects and advantages of the present invention will be better understood from the description given below of a particular embodiment of the invention presented by way of non-limiting example, with reference to the accompanying drawings in which: - Figure 1 is a perspective view of an iron equipped with a liquid atomizer according to a particular embodiment of the invention; FIG. 2 is a side view of the ironing apparatus of FIG. 1 schematically illustrating the reservoir and pump for supplying the atomizer; FIG. 3 is a longitudinal sectional view of the atomizer equipping the atomizer; Figure 4 is a top view of the micro-perforated membrane.

Only the elements necessary for the understanding of the invention have been represented. To facilitate the reading of the drawings, the same elements bear the same references from one figure to another.

FIG. 1 represents a steam iron 1 comprising, in a manner known per se, a sole 2 in thermal contact with a heating body, not shown in the figures, containing an electric resistance of a power of the order of 1600 W and having a vaporization chamber sized to produce a steam flow of the order of 20 gr / min to be distributed through holes in the sole 2, the temperature of the sole 2 being controlled by a thermostat of which the set temperature can be changed by the user by means of a setting knob 3.

The sole 2 is surmounted by a plastic casing 4 incorporating a grip handle 40 and comprising a heel 41 on which the iron can stand vertically during the inactive ironing phases, the heel 41 being advantageously equipped with a connector , not visible in the figures, allowing the electrical connection of the iron to a charging base.

According to FIG. 2, the casing 4 encloses a reservoir 5 of water, schematically represented in dashed lines, and has a tapered front end supporting a spraying device consisting of an ultrasonic liquid atomizer 6 producing micro-droplets, of sizes mostly between 30 pm and 60 pm in diameter, to moisten a spray zone located in front of the front tip of the sole 2.

Preferably, the iron 1 also comprises a scraper element 10 extending outside the soleplate 2 heating, at a distance of about 3 mm from the edge of the soleplate 2, allowing to penetrate mechanically the droplets of liquid inside the laundry to be ironed before the sole 2 heating reaches the spray area. Such a scraper element 10 is written in more detail in the patent application FR1158318 filed by the applicant.

According to FIG. 3, the atomizer 6 comprises a hollow cylindrical shell 60 of plastics material comprising a lateral protrusion 61 provided with a bore adapted to receive a fastening screw of the atomizer 6 on the casing 4 of the iron, the envelope 60 comprising a reception chamber 62 in which is disposed an electromechanical aerosol generator 7 operating in the range 50 kHz to 200 kHz.

The receiving chamber 62 has an open lower end 62A and an opposite end having an opening 62B communicating with a supply chamber 63 located above the receiving chamber 62 when the iron is resting on its sole 2, the chamber supply 63 having an upper end closed by a cover 64 and comprising a lateral orifice 63A forming a vent ensuring an atmospheric pressure of the feed chamber 63, this vent 63A is advantageously equipped with a filter, not shown in the figures, preventing the intrusion of a foreign body into the feed chamber 63.

According to FIGS. 2 and 3, the feed chamber 63 receives water from the tank 5 via a feed circuit comprising a water inlet pipe 50 passing through the lid 64, the inlet duct water 50 being connected to a pump 51, shown schematically in FIG. 2, the operation of which is controlled by means of a push button 11 arranged in front of the handle 40. Preferably, the supply circuit also comprises a filter water and an antibiotic diffuser device, such as colloidal silver, not shown in the figures.

As can be seen in FIG. 3, the aerosol generator 7 comprises a piezoelectric ceramic 8 bonded to a vibratory displacement amplifying tube 9 traversed by a cavity 90 comprising the liquid to be atomized, the cavity 90 extending along an axis of revolution R of the horn 9 and being closed at one end by a micro-perforated membrane 91 of small thickness, between 20 and 200 μm, mechanically and acoustically coupled to the horn 9.

The piezoelectric ceramic 8 is in known manner electrically powered by means of a power supply circuit, not shown in the figures, providing an alternating current across the piezoelectric ceramic 8, the latter being electrically powered only when the button pusher 11 is operated by the user.

Preferably, the trunk 9 has a shoulder 92 on which the piezoelectric ceramic 8 is glued and comprises a cylindrical body 93 of smaller section at the longitudinal end of which the micro-perforated membrane 91 is mechanically and acoustically fixed, for example by gluing. brazing, crimping or welding. For example, the trunk 9 has a diameter of about 16 mm at the shoulder 92 supporting the piezoelectric ceramic 8 and a diameter of about 8 mm at the height of the cylindrical body 93.

Preferably, the micro-perforated membrane 91 has a thickness of 50 μm and comprises an array of holes with a diameter of less than 40 μm, the holes being separated from each other by more than 400 μm. The micro-perforated membrane 91 is advantageously made of electroformed nickel or electro-formed stainless steel, preferably coated with gold, to combat the adhesion of limestone. By way of example, the micro-perforated membrane 91 has seventy 35-μm diameter holes, preferentially distributed in a V-shape as shown in FIG. 4, such a distribution of holes making it possible to obtain, with a single atomizer, a V-shaped micro-droplet diffusion spectrum which is adapted to match the shape of the front tip of the sole 2.

The cavity 90 has, opposite the micro-perforated membrane 91, an open end communicating with the feed chamber 63 via the opening 62B so that the water present in the feed chamber 63 flows into the cavity 90.

More particularly according to the invention, the flow rate of the pump 51 supplying the cavity 90 is greater than the flow rate of the atomizer 6 during operation, and the horn 9 preferably comprises two exit holes 94 aligned along a horizontal axis and arranged symmetrically with respect to the axis of revolution R of the horn 9, each outlet hole 94 opening into an annular discharge chamber 65, surrounding the cylindrical body 93 of the horn 9, which communicates with a bypass duct 66 to the tank 5. A For example, the atomizer 6 has a water spraying rate of the order of 9 gr / min to optimally moisten the clothes to be ironed and the pump 51 supplies water to the feed chamber 63 with a flow rate of the order of 12 gr / min.

Preferably, the outlet holes 94 have a diameter greater than or equal to 2 mm to allow a good flow of the excess water sent by the pump 51 to the branch conduit 66, the outlet holes 94 being distant from the micro-perforated membrane 91 with a height h of the order of 2 mm to permanently have a thin film of water covering the micro-perforated membrane 91.

The operation of the iron equipped with such an atomizer 6 will now be described.

During an ironing session, when the user wishes to moisten the laundry to remove difficult folds or creases, he presses the push button 11 to simultaneously cause the start of the pump 5 and the electrical excitation of the piezoelectric ceramic 8 which then generates vibratory displacements which are amplified by the cylindrical body 93 of smaller diameter, as is explained in more detail in the patent application FR2908329.

This results in a vibration of the micro-perforated membrane 91 in a longitudinal mode and a projection of micro-droplets of water through the micro-perforated membrane 91 in a V-shaped spectrum matching the shape of the front tip of the sole 2 iron with a flow rate of the order of 9 gr / min, the cavity 90 of the horn 9 being fed with a higher water flow so that the micro-perforated membrane 91 is permanently covered with a volume of constant water to have a uniform atomization rate, the excess water volume being returned to the tank 5 passing through the outlet holes 94 and then through the branch conduit 66 as schematically illustrated by arrows in Figure 3.

The micro-droplets thus emitted by the atomizer 6 are deposited on the surface of the fabric to be ironed and then impregnate the fabric being pressed by the scraper element 10 during the advancement of the iron, which causes a humidification and therefore a relaxation of the fibers of the fabric, before the hot sole 2 of the iron comes to dry the fabric, to obtain a perfect smoothing.

When the user no longer wishes to have a spray, he releases the push button 11, which simultaneously causes the pump 51 to stop and the electrical excitation of the piezoelectric ceramic 8 so that the emission of the micro-droplets is instantly interrupted, without the risk of untimely dripping through the micro-perforated membrane 91 thanks to the low height of water maintained above the latter.

Such an atomizer 6 thus has the advantage of being able to operate continuously until the water in the tank 5 is exhausted, the circulation of the excess water sent by the pump 51 having the advantage of stirring and renewing the water situated above the micro-perforated membrane 91, which makes it possible to evacuate any impurities that may stagnate on the micro-perforated membrane 91 and to improve the cooling of the micro-perforated membrane 91 during use extended atomizer 6.

Such an atomizer also has the advantage of consuming very little energy and producing micro-droplets of very regular size, which makes it particularly suitable for use on a low-consumption iron and especially on an iron. wireless.

Finally, such an atomizer comprising a vibrating horn in a longitudinal mode has the advantage of having a diffusion spectrum of the micro-droplets which depends directly on the distribution of the holes on the microperforated membrane. It is thus possible to obtain a V-shaped microdroplet diffusion spectrum which is adapted to match the shape of the front tip of the sole so as to moisten the laundry on the front and sides of the front tip of the sole. without projecting micro-droplets on the iron casing.

Of course, the invention is not limited to the embodiment described and illustrated which has been given by way of example. Modifications are possible, particularly from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Thus, in an alternative embodiment of the invention, the horn may have only one exit hole communicating with the bypass duct.

Thus, in an alternative embodiment of the invention not shown, the exit holes may have a passage section of non-circular shape and be of smaller size.

Thus, in an alternative embodiment of the invention, the pump may also operate continuously or episodically, when the piezoelectric ceramic is not electrically powered, that is to say outside the atomization phases of liquid by the atomizer. Thus, the pump can operate as soon as the iron is electrically connected to the electrical network. Such an embodiment variant has the advantage of ensuring a continuous washing of the upper surface of the membrane by the circulation of water.

Claims (18)

1) Atomizer (6) of liquid comprising a piezoelectric element (8) fixed on a trunk (9) amplifying vibratory displacements comprising a cavity (90) containing the liquid to be atomized, said trunk (9) comprising a first part (92) ) receiving the piezoelectric element (8) and a second part (93), distinct from the first part (92), mechanically and acoustically coupled to a micro-perforated membrane (91) closing one side of said cavity (90), characterized in that said cavity (90) is fed with liquid from a reservoir (5) with a flow rate greater than the atomizer (6) atomization rate in operation and in that said horn (9) comprises at least one outlet hole (94) connecting the cavity (90) to a bypass duct (66) to the reservoir (5). 2) Atomizer (6) of liquid according to claim 1, characterized in that said cavity (90) is fed with liquid from the reservoir by means of a pump (51) operating continuously during the atomization phases of liquid by the atomizer. 3) Atomizer (6) of liquid according to any one of claims 1 to 2, characterized in that said piezoelectric atomiser vibrates in a longitudinal mode in the range 50 kHz to 200 kHz. 4) Atomizer (6) of liquid according to any one of claims 1 to 3, characterized in that the horn (9) has a sectional variation between the first portion (92) supporting the piezoelectric element (8) and the second portion (93) coupled to the micro-perforated membrane (91). 5) liquid atomizer according to any one of claims 1 to 4, characterized in that the micro-perforated membrane (91) is attached to a longitudinal end of the horn (9). 6) Atomizer (6) of liquid according to any one of claims 1 to 5, characterized in that the horn (9) has an axis of revolution and comprises at least two outlet holes (94) arranged symmetrically with respect to said axis of revolution, said exit holes (94) communicating with an evacuation chamber (65) connected to the bypass duct (66) to the reservoir (5). 7) Atomizer (6) of liquid according to claim 6, characterized in that the micro-perforated membrane (91) is coupled to one end of a cylindrical body (93) of the horn (9) and in that the holes outlet (94) are provided on the cylindrical body (93). 8) Atomizer (6) of liquid according to any one of claims 1 to 7, characterized in that the or said exit holes (94) are spaced from the micro-perforated membrane (91) a height h less than 10 mm and preferably of the order of 2 mm. 9) Atomizer (6) of liquid according to any one of claims 1 to 8, characterized in that the or said outlet holes (94) have a diameter greater than or equal to 2 mm. 10) Atomizer (6) of liquid according to any one of claims 2 to 9, characterized in that it comprises a supply chamber (63) communicating on the one hand with the cavity (90) and secondly with a water inlet duct (50) connected to the pump (51), said supply chamber (63) having an air inlet (63). 11) Atomizer (6) of liquid according to claim 10, characterized in that the air inlet port (63A) comprises a filtration device preventing the intrusion of a foreign body into the feed chamber ( 63A). 12) Atomizer (6) of liquid according to any one of claims 1 to 11, characterized in that the cavity (90) is supplied with liquid from the tank (5) by a supply circuit comprising a filter to water and a dispensing device of an antibiotic product. 13) Iron (1) comprising a sole (2) heated surmounted by a housing (4) enclosing a reservoir (5), characterized in that it comprises a liquid atomizer (6) according to any one of the claims 1 to 12. 14) Iron (1) according to claim 13, characterized in that said atomizer (6) is carried by the housing (4) and moistens a treatment zone located outside the sole (2) . 15) Iron according to any one of claims 13 to 14, characterized in that the atomizer (6) sprays liquid with a flow rate of between 6 and 20 gr / min and preferably of the order of 9 gr / min. 16) Iron according to any one of claims 13 to 15, characterized in that the atomizer (6) diffuses a mist of microdroplets whose average diameter is between 30 pm and 60 pm. 17) An iron according to any one of claims 13 to 16, characterized in that the atomizer has a diffusion spectrum adapted to moisten a treatment zone extending along the two edges of a front tip of the sole (2). 18) Iron (1) according to claim 17, characterized in that the holes of the micro-perforated membrane (91) are distributed in a V-shape.