JP4799687B2 - Atomization device - Google Patents

Description

  The present invention relates to an atomization device that atomizes a liquid using surface acoustic waves.

Conventionally, an atomization device that atomizes a predetermined liquid using a piezoelectric material that propagates a surface acoustic wave has been developed. In the atomization process by this atomization device, in order to perform stable atomization, it is important to extend the liquid thinly into a film and supply the liquid stably.
For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2008-104974), a water retention material (film forming member) having a minute gap is provided on the surface of propagation of surface acoustic waves, and liquid is supplied into the gap to atomize the film. It is described.
Patent Document 2 (Japanese Patent Laid-Open No. 7-116574) describes an ultrasonic atomizer that atomizes a liquid supplied to a diaphragm through a hole provided in the diaphragm.

JP 2008-104974 A Japanese Patent Laid-Open No. 7-116574

However, the atomization apparatus of Patent Document 1 has a problem that the base and the water retaining material are separated from each other, and the amount of mist atomized from the base is small. In addition, since it is necessary to provide a minute gap to supply the liquid in a film form, parts and work that require precise accuracy are required, and the liquid can be supplied stably depending on the orientation of the atomizing surface. There is also a problem that it cannot be done.
Further, the base body generates heat due to the vibration energy of the base body, which may cause malfunction in the surface acoustic wave generator.
Moreover, since the apparatus of patent document 2 is atomized through the hole provided in the diaphragm, the process of the hole was required and there existed a possibility of a cost increase.

The present invention has been made to solve such a conventional problem, and an object thereof is to provide an atomization device having a simple structure capable of atomizing a large amount and uniform mist.
Another object of the present invention is to provide an atomization device that suppresses heat generation due to loss of energy generated by surface acoustic waves.
Furthermore, the other object of this invention is to provide the atomization device which can atomize the mist which has the component which has a specific function.

(1) The atomization device of the present invention is
A substrate made of a piezoelectric material;
A water retaining material that directly contacts the substrate and supplies a liquid to the surface of the substrate;
A surface acoustic wave generator provided on the surface of the substrate;
A liquid storage unit connected to the water retention material and supplying a liquid to the water retention material, and an atomization device comprising:
The water retaining material is arranged such that a contact portion thereof is in line contact with the base body .
(2) In the atomization device according to (1), the substrate is cut obliquely with respect to a direction orthogonal to the traveling direction of the surface acoustic wave.
(3) In the atomization device according to the above (1) or (2), the base is provided with a heat radiating plate.
(4) Moreover, in the atomization device in any one of said (1) thru | or (3),
The substrate is provided with a rotation mechanism, and the substrate is rotated around the water retaining material by the control of the rotation control means.

According to the present invention, the water retaining material that has absorbed the liquid is disposed in direct contact with the surface of the substrate, so that the liquid can be atomized in a large amount and uniformly and sprayed as a fine mist.
Further, since the liquid can be held in the water retaining material, it can be arranged in the up, down, and sideways directions regardless of the orientation of the substrate.

It is a whole block diagram of the atomization device of embodiment of this invention. It is sectional drawing which shows the example of the shape of the non-longitudinal direction of the water retention material applied to the atomization device of embodiment of this invention. It is explanatory drawing explaining the 1st modification which concerns on the atomization device of embodiment of this invention. It is explanatory drawing explaining the 2nd modification which concerns on the atomization device of embodiment of this invention. It is explanatory drawing explaining the 3rd modification which concerns on the atomization device of embodiment of this invention, (a) is a case where a water retention material is arrange | positioned above a base | substrate, (b) is a case where it arrange | positions on a side, c) shows a case where it is arranged on the lower side. It is explanatory drawing explaining the base | substrate which concerns on the atomization device of embodiment of this invention, (a) is a base | substrate which has not cut | disconnected the front-end | tip part diagonally, (b) is a base | substrate which cut | disconnected the front-end | tip part diagonally. is there. It is a schematic diagram which shows the heat_generation | fever evaluation result of the base | substrate which concerns on the atomization device of embodiment of this invention, (a) what cut | disconnected the front-end | tip part diagonally, (b) is the rectangular shape which does not cut | disconnect a front-end | tip part diagonally. Is. It is explanatory drawing explaining the 4th modification which concerns on the atomization device of embodiment of this invention. It is explanatory drawing explaining the aspect which attaches the atomization device of embodiment of this invention to the heat sink. It is explanatory drawing explaining the other aspect which attaches the atomization device of embodiment of this invention to the heat sink.

In a preferred embodiment of the present invention, a substrate made of a piezoelectric material, a surface acoustic wave generator provided on the surface of the substrate, and a portion that comes into direct contact with the substrate and makes a line contact with the substrate. A water retention material that is arranged and supplies liquid to the surface of the substrate;
The atomization device is configured by a liquid storage unit connected to the water retention material and supplying liquid to the water retention material ,
The liquid supplied from the water retaining material is atomized by the surface acoustic wave generated on the surface of the substrate by the surface acoustic wave generator.
The liquid to be atomized includes various liquids depending on the purpose, and is not particularly limited. Examples thereof include distilled water and a solution containing functional components described later in advance.

The base is a vibration plate that transmits vibrations from the piezoelectric material on which the comb-shaped electrodes are formed and atomizes the liquid contained in the water retaining material that is in direct contact with the substrate, such as a rectangular piezoelectric ceramic with a flat surface. Preferably used.
In addition, a rectangular plate is used as the shape of the base body, but the front end portion in the traveling direction of the surface acoustic wave may be cut obliquely.
By cutting the tip part diagonally, when the surface acoustic wave that has traveled is reflected by the tip part, the surface acoustic wave travels within the substrate without returning the direction of the surface acoustic wave to the original direction. By dispersing the direction in any direction, the attenuation of the surface acoustic wave can be suppressed.
In addition, by making the tip portion obliquely cut, a difference can be formed in the time required for surface acoustic waves propagating in the same direction to reach the tip portion, and the surface acoustic waves at the tip portion of the substrate are reflected. Heat generation due to energy loss or the like generated at the time can be suppressed.

The material of the piezoelectric material forming the substrate is not particularly limited. For example, lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), BaTiO ₃ ceramics, piezo (PZT), and polyvinylidene fluoride (PVDF). Various known materials such as can be applied.

In addition, since the substrate absorbs vibration energy and becomes high temperature, it has a heat dissipation property, a material that is slippery with respect to the water retaining material (a material that does not wear the water retaining material), a material that is corrosion resistant to liquid, etc. It is also preferred that the surface is coated. As what satisfies such a requirement, for example, DLC (diamond-like carbon) coating can be mentioned.

In addition, it is more preferable that a lyophilic treatment is performed on a portion of the surface of the substrate to which a liquid is supplied from the water retention material.
By the lyophilic treatment, the liquid supplied by the water retention material can be made thinner and more easily adapted to the surface of the substrate, and more stable atomization can be performed.
As the lyophilic treatment, a known lyophilic coating such as Teflon (registered trademark) resin-based coating or glass fiber (coating) -based coating can be applied.

Moreover, it is preferable that the heat sink is provided in the lower part of the base. This is because heat generated from the substrate is dissipated to eliminate the malfunction of the surface acoustic wave generator. For example, a metal plate such as an aluminum plate.

The surface acoustic wave generating unit is a member that is provided on the surface of the substrate made of a piezoelectric material and generates surface acoustic waves that propagate through the surface of the substrate. Examples thereof include comb-shaped electrodes formed by screen printing and the like. Connected to power.
Further, other known SAW elements (Surface Acoustic Wave elements) may be applied as long as they have a function of vibrating a water retaining material described later.

The water retention material is a member composed of a porous material having water absorption and water retention properties. As the material, a porous material or a fiber molded body (for example, a glass material) such as a ceramic material, a synthetic resin material, or a metal material is used. And those formed by combining one or more of fiber, carbon fiber, metal fiber and the like).
In addition, the amount of liquid supply can be changed by changing the material and the cross-sectional area, thereby controlling the amount of atomization.

Although the case where the water retaining material is brought into contact with a surface, a line, or a point can be considered as a mode of direct contact with the surface of the substrate, it can be directly contacted with the substrate in a linear manner from the experimental results described later. A large amount of mist can be atomized, which is preferable.

Further, the water retaining material has a role of atomizing the liquid held by directly contacting the surface of the substrate and receiving the vibration of the surface acoustic wave of the substrate, and can withstand contact wear with the vibrating substrate. preferable.

In addition, the water retaining material can be arranged with an angle α (for example, about 10 to 30 °) without being orthogonal to the traveling direction of the surface acoustic wave.
By arranging at an angle α without being orthogonal to the traveling direction, a difference can be provided in the time for the surface acoustic wave to reach the water retention material, and a time difference can be created in the timing of atomization from the water retention material. .
That is, the liquid in the part of the water retaining material that the surface acoustic wave has reached earlier is atomized first, and the part in which the surface acoustic wave has arrived later is atomized later. Since it atomizes, fine mist can be generated.

As a ceramic material of the porous body and fiber molded body constituting the water retention material, single oxides such as silica, alumina, magnesia, titania, zirconia, or mullite, zeolite, bentonite, ceolite, attapulgite, sillimanite, kaolin, Sericite, diatomaceous earth, feldspar, square mesh viscosity, silicate compounds (perlite, vanamicurite, sericite, etc.)
Examples of natural fiber materials include pulp fibers, cotton, wool fibers, and hemp fibers. Examples of synthetic resin materials include polyester, nylon, rayon, urethane (including polyurethane), acrylic, and polypropylene, and metal materials. Examples include stainless steel, copper, titanium, tin, platinum, gold, and silver. Moreover, carbon fiber etc. are used suitably.

In addition to the shape of the porous body and the fiber molded body, a honeycomb structure and a corrugated structure are exemplified, and a pipe shape, a sheet shape, a pleat shape, and the like are also exemplified.
The necessary condition as a water retention material is that it has excellent water absorption and water retention.
In addition, as for the shape of the water retaining material, various non-longitudinal cross-sectional shapes such as a circle, a semicircle, a quadrangle, and a triangle can be considered, and there is no particular limitation.
In addition, it is preferable that the water-retaining material having these shapes is in direct contact with the substrate in a linear form, so that the mist from the water-retaining material can be more atomized and uniform.

Further, a plurality of water retaining materials can be arranged in parallel on the surface of the substrate. For example, the amount of atomization can be increased by arranging two in a line in the traveling direction of the surface acoustic wave.

Further, the water retaining material may be impregnated with a functional component that can be dissolved in water or a functional component that can be dispersed in a colloidal form.
In addition to being able to atomize as a mist containing a functional component pre-impregnated with a water retaining material, the liquid storage unit described later may contain these functional components in advance. Since it is not necessary to include a sex component, the functional component can be atomized by supplying only moisture.

In addition, functional ingredients to be preliminarily contained in the liquid or impregnated in the water retention material include various vitamins, amino acids, tea extract (catechin, tannin, saponin, theanine, caffeine, etc.), hyaluronic acid, collagen, aroma Organic soluble components such as essential oils, coffee beans, tea confectionery, wasabi, hinokitiol, chitin, chitosan, propolis, etc., and other inorganic (inorganic soluble components) are functionally capable of dispersing silver or salt in a colloidal form. Examples of the component include platinum nanoparticles.

Here, “functionality” means a property that makes the living environment comfortable and can improve health, deodorization (deodorization, decomposition, etc.), antimicrobial (antibacterial, bactericidal, bacteriostatic, antifungal) , Antiviral, etc.), relaxation (aromatherapy), moisturizing, antioxidant, harmful organism repellent, antistatic, dustproof, etc. .

The liquid storage unit is configured by a storage container that stores the liquid to be atomized and always supplies the liquid directly or indirectly to the water retaining material by using a capillary phenomenon or the like.
In addition, you may attach a liquid quantity sensor to the bottom part in a storage container. As a result, for example, the liquid amount sensor can generate a signal when the liquid in the storage container is exhausted to prompt the replenishment of the liquid.
In addition, the liquid storage part and the water retaining material may be directly connected, or may be indirectly connected via an infusion member.

The infusion part is made of a material that can absorb and infuse liquid by capillary action as in the case of the water retaining material and the liquid storage part.
And like a water retention material, you may comprise with components consisting of a fiber, resin, ceramics, etc., and the supply amount of a liquid can be changed by changing the material and cross-sectional area.
In addition, the functional component that can be dissolved in water or the functional component that can be dispersed in a colloidal form may be impregnated in advance in the infusion part or the liquid storage part. As a result, the functional component can be sprayed at a high concentration or over a relatively long period of time.

Below, the Example which concerns on the atomization device to which this invention is applied is explained in full detail with reference to drawings.
As shown in FIG. 1, the atomizing device of the example is provided with a comb-shaped electrode 2 as surface acoustic wave generating means on the surface of a base 1 made of a piezoelectric material of LiNbO ₃ .
The comb-shaped electrode 2 is connected to a high-frequency power source 21, and when an operator operates an input means (not shown), a current flows from the high-frequency power source 21 to the comb-shaped electrode 2 to generate a predetermined voltage between the comb-shaped electrodes. Thus, the substrate 1 is minutely vibrated.
The tip 101 of the substrate 1 is cut into an oblique shape at an angle θ.

In addition, a water retaining material 3 made of porous fibers is disposed at the tip of the surface acoustic wave traveling direction from the comb-shaped electrode 2 so as to be in direct contact with the surface of the substrate 1.
One end in the longitudinal direction of the water retaining material 3 having a circular cross-section is connected to an infusion member 4 made of a water-permeable ceramic material, and indirectly supplies liquid from the liquid reservoir 5 via the infusion member 4. Have come to receive.
Further, the liquid is stored in the liquid storage unit 5, and the liquid is always supplied to the water retaining material 3 due to a capillary phenomenon or the like.

In addition, a lyophilic region 7 is formed on the surface of the substrate 1 in a predetermined range with a region where the water retaining material 3 is in contact as a center. Teflon (registered trademark) is coated as a lyophilic treatment for forming the lyophilic region 7.
Thus, since the periphery of the surface of the substrate 1 where the water retaining material 3 is in direct contact is lyophilically treated, the liquid supplied from the water retaining material 3 can be spread thinly on the substrate surface, and the substrate 1 is vibrated. The liquid can be atomized uniformly.
In addition, the same effect can be acquired also by making the water retention material 3 contain lyophilic property by including surfactant.

In FIG. 2, the cross-sectional example of the non-longitudinal direction of the water retention material 3 is shown.
Although FIG. 1 shows the case where the water retaining material 3 having a circular cross section is used, as shown in FIG. 2, the cross sectional shapes are (a) round, (b) oval, (c) half Examples include a circle, (d) an inverted triangle, (e) a diamond shape, and (f) a quadrangle.
The semicircular shape of (c) is preferably such that the arc side is in direct contact with the substrate 1, and the inverted triangle shape of (d) is such that one corner is in contact with the substrate 1 with the triangle reversed in cross-sectional shape. It is preferable to arrange them as follows.
As will be described later, from the viewpoint of generating a large amount of mist and suppressing the heat generation of the base body 1, the water retaining material 3 is arranged so as to be in line contact rather than surface contact as a mode of directly contacting the base body 1. That is, (a) a round shape, (b) an elliptical shape, (c) a semicircular shape, (d) an inverted triangle shape, and (e) a diamond shape, in such a manner that the contacting portion is in line contact with the substrate 1. It is preferable to arrange.

FIG. 3 shows a first modification of the embodiment. In the first modification, like the water retention material 3, the second water retention material 6 is arranged in parallel with the water retention material 3 in the traveling direction of the surface acoustic wave in a mode in which the second water retention material 6 is in direct contact with the base 1. The liquid storage part 5 is connected via the infusion member 4.
The atomization device of the first modification can generate a larger amount of mist because the liquid is atomized by a plurality of water retaining materials.

FIG. 4 shows a second modification of the embodiment. In the second modification, the water retaining material 3 is disposed so as to contact the tip of the base body 1. The tip portion is the portion that is most susceptible to vibration energy of the substrate 1 and can be atomized from the water retaining material 3 uniformly and in a large amount.

FIG. 5 shows a third modification of the embodiment. In the third modified example, a rotation mechanism 8 is provided on the base body 1 and the base body 1 is rotated around the water retaining material under the control of a rotation control means 9 such as a PC.
Thereby, when the water retaining material 3 is disposed on the upper side of the base body (a), when the water retaining material 3 is disposed on the lateral side of the base body 1 (b), when the water retaining material 3 is disposed on the lower side of the base body 1 ( c), etc., the positional relationship between the water retaining material 3 and the substrate 1 can be in various postures, and the spraying direction of the mist can be freely set.
Furthermore, it is possible to appropriately cope with the case where it is desired to switch the spraying direction of the mist to various directions along the way.
When manually operating the rotation mechanism 8, the rotation control means 9 can be omitted.
Moreover, when the infusion member 4 is interposed, the infusion member 4 can be configured to be extendable and contractable so as to follow the rotation of the base body 1.

Next, referring to FIG. 6, the operation of the substrate with the tip portion cut obliquely will be described.
FIG. 6A shows a base body whose front end portion is not cut obliquely, and FIG. 6B shows a base body whose front end portion is cut obliquely.
As shown to (a), when the front-end | tip part 101 of the base | substrate 1 is orthogonally crossed with respect to the advancing direction 22 of a surface acoustic wave, the advancing direction 22 of the surface acoustic wave sent from the surface acoustic wave generation part 2 is the base | substrate 1 Then, the light is reflected by the tip 101 and its direction is changed by 180 degrees, and continues to propagate in the backward traveling direction 22b.
Such a surface acoustic wave reversal phenomenon causes resonance of the substrate 1 and causes problems such as coarsening of the atomized mist or generation of heat of the substrate 1.
On the other hand, as shown in (b),
In the base body in which the tip 101 of the base body 1 is cut obliquely with respect to the direction 23 perpendicular to the surface acoustic wave traveling direction 22 (angle θ in the direction of the surface acoustic wave generating section), the elasticity has progressed in the traveling direction 22. After the surface wave reaches the tip portion 101 of the substrate 1, it reflects in the traveling direction 24 different from the backward traveling direction 22b, and the reflected surface acoustic wave in the traveling direction 24 is further reflected by another edge of the substrate 1, Proceed in the direction of travel 25.
Thus, by cutting the tip portion 101 of the substrate 1 obliquely at an angle θ, the surface acoustic wave can be dispersed in various traveling directions, and the atomized mist is made uniform, resonance of the substrate 1 or the like. Heat generation can be suppressed.
Note that the angle θ is not required to reflect the traveling direction of the surface acoustic wave reflected at the tip 101 in the reverse traveling direction 22b, and therefore the angle θ may be greater than 0 degrees and less than 90 degrees, which will be described later. From the experimental results, 5 to 60 degrees is preferably adopted.

FIG. 7 shows a heat generation evaluation result of the base body obtained by obliquely cutting the tip portion 101 of the base body 1.
A base when the tip 101 is obliquely cut (a), a rectangular shape (b), and two types of bases 1 are mounted on an aluminum plate as a heat sink 11, and an applied voltage of 50 Vp-p is applied. The surface temperature of 1 was measured by thermography.
As a result, the substrate 1 (a) cut obliquely at an angle θ showed an effect of suppressing heat generation, while the rectangular shape (b) generated heat. Specific numerical values are shown in Table 1 described later.

FIG. 8 shows a fourth modification of the embodiment.
In the fourth modified example shown in FIG. 8, the water retaining material 3 is disposed on the base at an angle α.
The angle α is an angle formed with the line 102 orthogonal to the traveling direction 22 of the surface acoustic wave.
In this case, since the atomization proceeds from the liquid stored in the water retaining material 3 to which the surface acoustic wave has arrived early, the liquid stored in the water retaining material 3 in which the surface acoustic wave arrives slowly is atomized later. A time difference can be made in the atomization timing, and heat generation in the base 1 can be suppressed.

Table 1 shows the amount of mist generated from the atomizing device and the heat generation of the substrate 1 when the oblique cut angle θ of the substrate 1 shown in FIG. The experimental result which evaluated temperature is shown. The applied voltage was 50 Vp-p.
(A) of Table 1 is a case where an experiment was conducted by bringing the water retaining material into direct contact with the substrate 1 (expressed as surface distance = 0),
(B) in Table 1 shows a case where the water retaining material was not directly brought into contact with the base body 1 but was placed at a distance of 0.5 mm (expressed as surface distance = 0.5).
In the table, the amount of mist is a numerical value in units of ml / h, and the amount of decrease from the liquid storage unit 5 was measured. Further, the heat generation was measured by thermography of the surface temperature of the substrate 1.
Furthermore, the types of water-retaining materials are three types of cross-sectional shapes: round (as shown in FIG. 2 (a)), square (as shown in FIG. 2 (f)), and inverted triangle (as shown in FIG. 2 (d)). Was used.
Triangular objects were inverted triangles in cross-sectional shape and arranged so that one corner thereof was in contact with the substrate 1. Therefore, the triangular ridge line is in contact with the base 1.
From the results of Table 1 (a), the water retaining material having a round cross-section and an inverted triangle has a large amount of mist and a low exothermic temperature at any oblique angle θ. However, when the cross-sectional shape is a square, the amount of mist is small and not practical.
Further, from the results shown in Table 1 (b), the substrate 1 and the water retention material 3 which are arranged apart from each other have a small amount of mist and are not practical regardless of the water retention material having any cross-sectional shape.

FIG. 9 is a diagram for explaining a mode in which the atomizing device according to the embodiment is attached to the heat sink 11 made of aluminum.
As shown in FIG. 9, a part of both sides of the heat radiating plate 11 is notched inward, the notched plate part is bent inward, and the caulking 12 The substrate 1 can be attached to the heat sink 11.
Drawing 10 is a figure explaining other modes which attach the atomization device of an embodiment to a heat sink.
As shown in FIG. 10, a part of both sides of the heat radiating plate 11 is notched inward, and the notched plate portions are bent inward to form fixing protrusions 13 provided on both sides of the base 1. The substrate 1 can be attached to the heat radiating plate 11 so as to stop.
In FIGS. 9 and 10, the comb electrodes provided on the base body are illustrated as being exposed, but may actually be covered with a cover.

The atomizing device of the present invention uses a water-retaining material capable of absorbing a liquid to absorb the liquid and arrange it in direct contact with the surface of the substrate so that the liquid is atomized in a large amount and uniformly. Thus, it can be sprayed as a fine mist, and can be applied to industrial equipment such as a mist generator, an air purifier, and an air conditioner.
In addition, the atomization device can be arranged in the up, down, and sideways directions regardless of the orientation of the substrate, and the industrial applicability is extremely high.

1 Substrate 2 Comb electrode (surface acoustic wave generator)
DESCRIPTION OF SYMBOLS 3 Water retention material 4 Infusion member 5 Liquid storage part 6 2nd water retention material 7 A lyophilic area | region 8 Rotation mechanism 9 Rotation control means 11 Radiating plate 12 Caulking 13 Fixing protrusion 21 High frequency power supply 22 Travel direction 22b Reverse travel direction 23 Elasticity Direction orthogonal to surface wave traveling direction 22 Traveling direction 25 Traveling direction 101 Tip of substrate
102 Line α orthogonal to surface acoustic wave traveling direction 22 α Angle formed with line 102 orthogonal to surface acoustic wave traveling direction 22 θ Oblique with respect to direction 23 perpendicular to surface acoustic wave traveling direction 22 The angle formed by the tip of the substrate cut into

Claims (4)

A substrate made of a piezoelectric material;
A water retaining material that directly contacts the substrate and supplies a liquid to the surface of the substrate;
A surface acoustic wave generator provided on the surface of the substrate;
A liquid storage unit connected to the water retention material and supplying a liquid to the water retention material, and an atomization device comprising:
The water retaining material is arranged in such a manner that the contacting portion is in line contact with the substrate . 2. The atomization device according to claim 1, wherein the base is cut obliquely with respect to a direction orthogonal to the traveling direction of the surface acoustic wave. The atomizing device according to claim 1, wherein the base is provided with a heat radiating plate. The atomization device according to any one of claims 1 to 3, wherein a rotation mechanism is provided on the base body, and the base body is rotated around a water retaining material by control by a rotation control means.