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(11) | EP 1 775 027 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Micro-droplet generator Mikrotröpfchen-Erzeuger Générateur de micro-gouttelettes |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
Field of the Invention
[0001] The present invention relates to a micro-droplet generator, particularly to a micro-droplet generator which works by the piezoelectric effect, producing a well-defined flow of tiny droplets.
Description of Related Art
[0002] Currently available sprayers have two kinds, which work by direct pressure and by vibrations, generating pressure that disperses micro-particles. A common disadvantage of conventional sprayers is the need of large pressure when relatively large particles are generated, resulting in a large noise. For medical applications, spraying of relatively large particles is not required, but precise particle sizes are important. Therefore, sprayers working by vibration have recently been preferred for medical applications. Sprayers of this kind use ultrasound, generated by piezoelectric material, to produce micro-droplets. Shortcomings of these sprayers, however, are high power consumption, the need of a fan to drive micro-droplets into a given direction, a large volume, and non-uniform distribution of micro-particle sizes. Other sprayers which use piezoelectric material have spraying plates with holes of defined diameters to disperse micro-droplets, resulting in considerably reduced power consumption and well-defined micro-droplet sizes. Sprayers of this kind, disclosed in patent or sold on the market, are of two sub-kinds: Sprayers of the first sub-kind by direct vibrational pressure force micro-droplets through spraying plates, sprayers of the second sub-kind have vibrating spraying plates, causing micro-droplets to pass through. Sprayers of the first sub-kind have a higher power consumption than sprayers of the second sub-kind. The latter in some versions use planes that are tapped on, e.g., planes attached to capillary tubes transmitting liquid at ends thereof. These designs, however, have the following shortcomings:
- 1. Energy is easily dissipated.
- 2. Volume is large.
- 3. Manufacturing cost is high.
- 4. Tapped planes attached to capillaries allow only for small spraying angles.
- 5. Spraying is performed with limited effectiveness.
[0003] Document JP-A-60187362 discloses a micro-droplet generator according to the preamble of claim 1.
SUMMARY OF THE INVENTION
[0004] It is an object of the present invention to provide a micro-droplet generator allowing precise control of flow of micro-droplets as described in the claims.
[0005] Another object of the present invention is to provide a micro-droplet generator having a small volume and low manufacturing cost.
[0006] A further object of the present invention is to provide a micro-droplet generator having a flat shape.
[0007] The present invention can be more fully understood by reference to the following description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig. 1 is a perspective view of the micro-droplet generator of the present invention when disassembled.
[0011] Figs. 5 - 7 are perspective views of the projection in other embodiments, fig. 7 showing a projection having guiding grooves according to the invention.
[0012] Fig. 8 is a sectional view of the present invention in a further embodiment of the top surface carrier.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] As shown in Fig. 1, the micro-droplet generator of the present invention mainly comprises: a main body 10; a spraying plate 20; a vibrating element 30; and a top surface 41, which is placed on a projection or a plan plate. The main body 10 has an inner chamber 11, accommodating liquid to be sprayed. A lateral opening 12 in the main body 10 connects the chamber 11 with the outside and houses the spraying plate 20. Liquid to be sprayed passes through the opening 12.
[0015] The main body 10 further has an upper side with an inlet 13, through which liquid to be sprayed is poured into the chamber 11. For mobile applications, e.g., ambulant medicine, the chamber 11 is preferably sized large enough for repeated spraying. For stationary applications, e.g., indoor spraying of liquid from a fixed installed supply, the inlet 13 preferably has a fixed connection thereto.
[0016] As shown in Fig. 2, the spraying plate 20 is laid into the opening 12, having a plurality of spraying holes 21 in a dense arrangement. The spraying holes 21 define sizes and spraying directions of sprayed micro-droplets, allowing for precise control thereof.
[0017] As further shown in Fig. 2, the spraying plate 20 has an inner side 22 facing the chamber 11 and contacting liquid to be sprayed therein.
[0018] Referring again to Figs. 1 and 2, the vibrating element 30 is made of piezoelectric material and placed on the spraying plate 20. Applying electric voltage to the vibrating element 30 causes vibrations thereof, driving vibrations of the spraying plate 20.
[0019] The vibrating element 30 and the spraying plate 20 are glued to each other. The spraying plate 20 and the opening 12 have round shapes, while the vibrating element 30 is shaped like a ring. As shown in Figs. 3 and 4, when electric voltage is applied to the vibrating element 30, vibrations thereof are performed in a direction thereto.
[0020] The main characteristic of the present invention lies in a projection 40 being placed in the chamber 11. The projection 40 has an inner end attached to an inner wall of the main body 10 and an opposite outer end carrying the top surface 41 which is parallel to the inner side 22 of the spraying plate 20, leaving a small space 50 in between.
[0021] When the vibrating element 30 is driving vibrations of the spraying plate 20, the space 50 has a varying width. As shown in Fig. 3, whenever the spraying plate 20 moves outward, away from the top surface 41 of the projection 40, the space 50 becomes wider, so that liquid flows into the space 50. On the other hand, when the spraying plate 20 moves inward, towards the top surface 41 of the projection 40, the space 50 becomes narrower, so that liquid is pressed through the spraying plate 20 and micro-droplets 51 are generated.
[0022] Liquid flow is controlled by grooves cut into the projection 40. As shown in Fig. 5, a face groove 42 that is shaped like a closed loop is cut into the top surface 41 of a projection 40a. Thereby, as shown in Fig. 3, a minimum space between the top surface 41 of the projection 40 and the inner side 22 of the spraying plate 20 is maintained, in which liquid stays due to capillary forces. As shown in Fig. 6, a projection 41b is employed having a chamfered top edge 44, so that a minimum space for liquid is provided into which liquid is drawn due to capillary forces. As shown in Fig. 7, according to the invention, at least one guiding groove 43 is cut into a periphery of a projection 40c, due to capillary forces facilitating flow of liquid to the top surface 41 of the projection 40c. By capillary forces, liquid to be sprayed readily flows into the space 50, even against gravitational forces.
[0023] For accommodating various liquids and casings, the top surface carrier may be the following devices. As shown is Fig. 8, a projection 40d shaped like the letter T is horizontally mounted on the main body 10, or as shown in Fig. 9, a plan plate 40e shaped like the letter q is vertically mounted on the main body 10.
[0024] The main characteristic of the present invention lies in installing of the projection 40 in the chamber 11. As shown in Figs. 3 and 4, placing the top surface 41 of the projection 40 close to the inner side 22 of the spraying plate 20 creates the narrow space 50, confining vibrational energy to a small volume, so that energy is saved and power consumption is low, allowing for battery use and prolonged use. Furthermore, effective transmission of vibrations of the spraying plate 20 to liquid inside the space 50 reduces required power for driving liquid through the spraying holes 21, allowing to reduce diameters thereof for a better spraying effect. The top surface is also implementable on a plan plate, or the top surface is integrated with the spraying plate 20 forming a chamber, to a similar effect.
[0025] What is more, as compared to conventional art, the present invention has a simplified driving system without any need for auxiliary devices, so that manufacturing cost is kept low and volume is reduced. Thereby, mobile applications are readily supported and flat shapes are realizable, making the present invention suitable for applications in ambulant medical devices or air conditioners.
a main body (10), having an inside with a chamber (11) accommodating liquid to be sprayed and a lateral opening (12) allowing liquid in said chamber to flow out;
a spraying plate (20), placed on said main body at said opening (12) thereof and having a plurality of spraying holes (21) in a dense arrangement as well as an inner side (22) facing said chamber (11) which contracts liquid in said chamber (11) ;
a vibrating element (30), glued on said spraying plate (20) and driving vibrations thereof; and
a top surface carrier (4), placed inside said chamber and having a top surface (41) that with said inner side of said spraying plate (21) forms an inner part of said chamber (11);
wherein upon said vibrations of said spraying plate (20) a narrow space between said inner side of said spraying plate (20) and said top surface (41) with varying width is generated, upon becoming wider sucking in liquid from said chamber (11), and upon becoming narrower pressing out liquid through said spraying holes (21), so that effective spraying of liquid is performed,
characterized in thatsaid top surface carrier (4) is a projection (40),
at least one guiding groove (43)is cut into a periphery of the projection (40), for facilitating the flow of liquid due to capillary forces to the top surface (41) of the projection (40) allowing liquid to flow in between said inner side of said spraying plate (20) and said top surface (41) of said projection (40).
einen Hauptkörper (10), der ein Inneres mit einer Kammer (11), die eine zu versprühende Flüssigkeit aufnimmt, und eine seitliche Öffnung (12), welche die Flüssigkeit aus der Kammer auslaufen lässt, aufweist;
eine Sprühplatte (20), die auf dem Hauptkörper an seiner Öffnung (12) angeordnet ist und eine Vielzahl von Sprühlöchern (21) in einer dichten Anordnung sowie eine innere Seite (22) gegenüber der Kammer (11), welche die Flüssigkeit in der Kammer (11) berührt, aufweist;
ein Vibrationselement (30), das auf die Sprühplatte (20) geklebt ist und ihre Vibrationen ansteuert; und
einen oberen Oberflächenträger (4), der im Innern der Kammer angeordnet ist und eine obere Oberfläche (41) aufweist, die mit der inneren Seite der Sprühplatte (21) einen inneren Teil der Kammer (11) bildet;
wobei bei den Vibrationen der Sprühplatte (20) ein schmaler Abstand zwischen der inneren Seite der Sprühplatte (20) und der oberen Oberfläche (41) von variabler Breite erzeugt wird, der, wenn er sich erweitert, Flüssigkeit aus der Kammer (11) ansaugt, und wenn er sich verengt, Flüssigkeit durch die Sprühlöcher (21) herausdrückt, so dass ein wirksames Sprühen von Flüssigkeit erfolgt,
dadurch gekennzeichnet, dass
der obere Oberflächenträger (4) ein Vorsprung (40) ist,
mindestens eine Führungsnut (43) in einer Peripherie des Vorsprungs (40) eingeschnitten ist, um die Strömung der Flüssigkeit durch Kapillarkräfte zur oberen Oberfläche (41) des Vorsprungs (40) hin zu erleichtern, so dass die Flüssigkeit zwischen der inneren Seite der Sprühplatte (20) und der oberen Oberfläche (41) des Vorsprungs (40) fließen kann.
un corps principal (10), comportant un intérieur avec une chambre (11) contenant un liquide à pulvériser et une ouverture latérale (12) permettant au liquide contenu dans la dite chambre de s'écouler ;
une plaque de pulvérisation (20), placée sur ledit corps principal au niveau de ladite ouverture (12) de celui-ci et comportant une pluralité de trous de pulvérisation (21) agencés de manière dense ainsi qu'un côté intérieur (22) faisant face à ladite chambre (11) qui est en contact avec le liquide dans ladite chambre (11) ;
un élément vibrant (30), collé sur ladite plaque de pulvérisation (20) et commandant les vibrations de celle-ci ; et
un support de surface supérieure (4), placé à l'intérieur de ladite chambre et comportant une surface supérieure (41) qui forme une partie intérieure de ladite chambre (11) avec ledit côté intérieur de ladite plaque de pulvérisation (21) ;
dans lequel, lors desdites vibrations de ladite plaque de pulvérisation (20), un espace étroit est généré entre ledit côté intérieur de ladite plaque de pulvérisation (20) et ladite surface supérieure (41) de largeur variable, qui, lorsqu'il s'élargit aspire le liquide depuis ladite chambre (11), et lorsqu'il rétrécit, repousse le liquide à travers lesdits trous de pulvérisation (21), de sorte que le liquide est pulvérisé de manière efficace,
caractérisé en ce queledit support de surface supérieure (4) est une protubérance (40),
au moins une rainure de guidage (43) est découpée dans une périphérie de la protubérance (40), pour faciliter l'écoulement de liquide du fait de forces capillaires appliquées à la surface supérieure (41) de la protubérance (40) permettant au liquide de s'écouler entre ledit côté intérieur de ladite plaque de pulvérisation (20) et ladite surface supérieure (41) de ladite protubérance (40).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description