JPH067721A - Ultrasonic spraying apparatus - Google Patents

Abstract

PURPOSE:To attempt to improve spraying efficiency and to make the amt. of spraying large by providing a lot of holes in an oscillating part surrounded by a fixed part fixed by means of a piezoelectric oscillator and making at least a part of the oscillating part into a curved structure. CONSTITUTION:When a composite body consisting of a piezoelectric oscillator 1 and an oscillating body 2 is driven, the piezoelectric oscillator 1 is oscillated and the oscillation is transmitted to the oscillating body 2. A liq. fed to the lower face of the oscillating body 2 being brought into contact with a liq. holding material 3 is sprayed through holes provided in the oscillating body 2 according to oscillation of the oscillating body 2. The direction of spraying can be diverged as the central part of the oscillating body 2 is curved into a concave or convex curved structure, with which the liq. holding material is brought into contact. A simple and lightweight structure can be obtd. thereby and spraying efficiency, a large amt. of spraying and fineness and uniformity of the sprayed particle can be improved thereby, too and the direction of spraying can be diverged or converged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic atomizing device for atomizing a liquid by elastic vibration generated by an ultrasonic exciter.

[0002]

2. Description of the Related Art Conventional ultrasonic atomizers include ultrasonic atomizers and nebulizers to which a bolted Langevin type vibrator is applied. The atomization device using a bolted Langevin type oscillator uses ultrasonic waves with a frequency of several tens of kHz, and has the advantage of being able to generate a large amount of fog, but also has the disadvantage of a complicated structure and large-scale device. Hold. On the other hand, the nebulizer uses ultrasonic waves in the MHz range and has the advantage that the particles are minute and has excellent uniformity, but it has the disadvantage that atomization efficiency is poor and it is difficult to generate a large amount of fog with low power. Hold.
That is, the conventional ultrasonic atomizer has a problem in atomization efficiency, large amount of atomization, fineness of particles, or driving power supply cost.

[0003]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide atomization efficiency, large amount atomization, fineness and uniformity of particles, small size and light weight of device, simple structure, and driving power supply cost. An object of the present invention is to provide an ultrasonic atomizing device which is satisfactory from any aspect of the body.

[0004]

An ultrasonic atomizing device according to claim 1 is a device for atomizing a liquid by elastic vibration generated by an ultrasonic exciter having a vibrating body fixed to a piezoelectric vibrator. In the sonic atomization device, the piezoelectric vibrator includes a piezoelectric ceramic and electrodes A and B formed on both end surfaces perpendicular to the thickness direction of the piezoelectric ceramic, respectively. Having a through hole that is penetrated in parallel to the thickness direction, the shape of the cross section perpendicular to the thickness direction forms a frame-shaped structure, and the length in the thickness direction and the outer edge and the inner edge of the frame die. The ratio to the shortest distance is substantially equal to 1, and the vibrating body is provided at a position covering the opening of the through hole or at least at one position inside the through hole, and the vibrating body is fixed to the piezoelectric vibrator. , A vibrating part surrounded by the fixed part, and the vibrating part has a large number of holes. Only Yes, the at least a portion of the vibrating section, characterized in that it forms a curved structure.

An ultrasonic atomizing device according to a second aspect of the present invention is characterized in that the frame die has an annular shape.

In the ultrasonic atomizing device according to a third aspect of the present invention, the means for supplying the liquid to the vibrating portion includes a liquid retaining material that absorbs the liquid and supplies the liquid to the vibrating portion. The material is in contact with the concave portion or the convex portion of the curved structure.

An ultrasonic atomizing device according to a fourth aspect is characterized in that one opening area of the vibrating portion and the other opening area of the vibrating portion in the hole are different from each other.

An ultrasonic atomizing device according to a fifth aspect of the present invention is characterized in that the resonance frequency of the piezoelectric vibrator is substantially equal to the resonance frequency of the composite of the piezoelectric vibrator and the vibrating body.

[0009]

When the ultrasonic atomizing device of the present invention is used, an alternating-current signal having a frequency substantially equal to the resonance frequency of the composite of the piezoelectric vibrator and the vibrating body is applied to the piezoelectric vibrator, and the piezoelectric vibration is applied. The child is excited. Excitation of the piezoelectric vibrator vibrates the vibrating body. The liquid supplied to the vibrating body is atomized through holes provided in the vibrating portion.
Atomization through the holes promotes fineness and uniformity of the particles, and can increase atomization efficiency. Further, since the atomization efficiency is high, a large amount of atomization can be realized with low power consumption and the device can be easily downsized. Since self-excited driving is possible and driving with a battery is easy, driving with low power consumption is possible in a form that can respond to environmental changes. In addition, since at least a part of the vibrating portion has a curved structure, it is possible to diverge the existence region of the fog.

The piezoelectric vibrator comprises a piezoelectric ceramic and electrodes A and B formed on both end surfaces of the piezoelectric ceramic which are perpendicular to the thickness direction. An alternating voltage is applied to the piezoelectric vibrator via the electrodes A and B, and the piezoelectric vibrator is excited. By adopting the piezoelectric vibrator having such a simple structure, the ultrasonic atomizing device can be downsized, and the liquid atomizing device can atomize the liquid with high efficiency.

The piezoelectric ceramic has a through hole penetrating in parallel with the thickness direction of the piezoelectric ceramic, and the vibrating body is provided at a position covering the opening of the through hole or at least at one position inside the through hole. Therefore, the vibration energy of the piezoelectric vibrator efficiently propagates to the vibrating body and vibrates the vibrating body, so that atomization efficiency can be increased. The vibrating body of the portion surrounded by the fixed portion fixed to the piezoelectric vibrator forms a vibrating section, and the vibrating section performs combined vibration integrated with the piezoelectric vibrator, so that the vibrating section is The supplied liquid is atomized by the combined vibration and is emitted as mist toward the upper part of the vibrating portion. Due to the synergistic effect of the vibration of the vibrating part and the action of the holes provided in the vibrating part, the atomization efficiency of the liquid is promoted, the amount of mist generated is increased, and the particle diameter is made uniform.

The shape of the cross section of the piezoelectric ceramic perpendicular to the thickness direction forms a frame type structure, and the ratio of the length in the thickness direction to the shortest distance between the outer edge and the inner edge of the frame type is approximately 1. By adopting the same structure, the combined vibration of the composite of the piezoelectric vibrator and the vibrating body is enhanced, and the atomization efficiency is increased. Further, since the frame shape is an annular shape, the combined vibration of the composite of the piezoelectric vibrator and the vibrating body is further enhanced, so that the atomization efficiency is further increased.

The means for supplying the liquid to the vibrating section comprises:
A liquid retaining material is provided to absorb the liquid and supply the liquid to the vibrating section. The liquid retaining material is in contact with the concave portion or the convex portion of the curved structure in the vibrating portion. When the liquid retaining material is in contact with the concave portion, the liquid supplied to the concave portion is atomized toward the convex portion of the curved structure through the hole provided in the vibrating portion. When the liquid retaining material is in contact with the convex portion, the liquid supplied to the convex portion is atomized toward the concave portion of the curved structure through the hole provided in the vibrating portion. The atomization through the holes not only promotes the fineness and uniformity of the particles but also increases the atomization efficiency, and can control the direction of the atomized fog. That is, the direction of the atomized mist is diverged when the liquid retaining material is in contact with the concave portion, and the direction of the atomized mist is converged when the liquid retaining material is in contact with the convex portion. It

Since one opening area of the vibrating portion in the hole is larger than the opening area of the other, the opening area of one side of the vibrating portion is defined as the inlet side, and the other opening area is defined as the outlet side. To decrease toward the exit side.
Therefore, when the liquid passes through the hole, the liquid is subjected to the throttling action by the hole. As a result, the atomizing action of the liquid is promoted by the synergistic effect of the throttling action and the vibration of the vibrating section, the amount of fog generated is increased, and the particle diameter is made uniform.

By applying a voltage to the piezoelectric vibrator when the resonance frequency of the piezoelectric vibrator is substantially equal to the resonance frequency of the composite of the piezoelectric vibrator and the vibrator, the vibrator is made efficient. Excitation, the atomization efficiency is promoted, and the amount of fog generated is further increased.

[0016]

1 is a sectional view showing an embodiment of an ultrasonic atomizing device of the present invention. In this embodiment, the piezoelectric vibrator 1 and the vibrating body 2 are used.
And a liquid retaining material 3. A terminal made of copper foil is fixed to the piezoelectric vibrator 1 with a conductive adhesive. The piezoelectric vibrator 1 is provided with a vibrating body 2. In FIG. 1, a power supply circuit and terminals for supplying an AC voltage to the piezoelectric vibrator 1 are omitted. The vicinity of the center of the vibrating body 2 is curved.
The liquid retaining material 3 is in contact with the curved concave portion of the vibrating body 2, and supplies liquid from the liquid retaining material 3 to the concave portion during use.

FIG. 2 is a perspective view showing the piezoelectric vibrator 1 in the ultrasonic atomizer of FIG. The piezoelectric vibrator 1 includes a piezoelectric ceramic 11 and electrodes D and G. The piezoelectric ceramic 11 has a columnar shape and has through holes penetrating in parallel with the polarization axis, with both end surfaces perpendicular to the polarization axis. The material of the piezoelectric ceramic 11 is TDK72A material (product name), the diameter is 24 mm, the thickness is 6 mm, the through hole is also cylindrical, and the diameter is 12
mm. Since the TDK72A material has a large electromechanical coupling coefficient, it is used in this example. Electrodes D and G are formed on the both end faces, respectively. Electrode D
A terminal P is attached to the electrode G and a terminal Q is attached to the electrode G.

FIG. 3 is a plan view of a composite body composed of the piezoelectric vibrator 1 and the vibrating body 2 as viewed from the top surface direction. A disk-shaped vibrating body 2 having a curved central portion is attached to a position of the upper end surface of the piezoelectric vibrator 1 that covers the opening of the through hole.
The vibrating body 2 is made of nickel, and is integrally fixed to the piezoelectric vibrator 1 by a ring-shaped fixing portion 12, and the vibrating body 2 surrounded by the fixing portion 12 forms a vibrating portion 13. The fixing portion 12 is fixed to the piezoelectric vibrator 1 via the electrode D. The through hole has a diameter of 14 mm and a thickness of 0.05 mm.

FIG. 4 is a view showing a cross section of the vibrating portion 13 that appears when cut along a plane perpendicular to the plate surface. The vibrating portion 13 is provided with a large number of fine holes 20 penetrating in the thickness direction thereof. In FIG. 4, the vertical cross-sectional shape and dimensions of the hole 20 are shown. The shape of the hole 20 is a mortar shape, and one having an opening area larger than the opening area of the other is used in this embodiment, and one opening is an inlet side and the other is an outlet side. The diameter of the inlet side is 0.1 mm, the diameter of the outlet side is 0.01 mm, and the holes 20 are arranged at equal pitches.

FIG. 5 is a partially enlarged plan view of the vibrating portion 13. In FIG. 5, the shape and arrangement and dimensions of the holes 20 are shown.

When the ultrasonic atomizing device of FIG. 1 is driven, an AC signal having a frequency substantially equal to the resonance frequency of the composite of the piezoelectric vibrator 1 and the vibrating body 2 is transmitted through the terminals P and Q to the piezoelectric vibrator. When applied to 1, the piezoelectric vibrator 1 is excited. At this time, the frequency of the AC signal substantially matches one of the resonance frequencies of the piezoelectric vibrator 1 alone. When the piezoelectric vibrator 1 is excited, the vibrating part 13 surrounded by the fixing part 12 integrally vibrates together with the piezoelectric vibrator 1. This vibrating part 13
The combined vibration of the liquid crystal effectively works to atomize the liquid. As the liquid retaining material 3, a material having a large liquid absorbing capacity and a lower acoustic impedance than the piezoelectric vibrator 1 is used in this embodiment. This is because ultrasonic waves from the piezoelectric vibrator 1 are suppressed from propagating into the liquid via the liquid retaining material 3 and being scattered, and the vibrating body 2 is vibrated efficiently. The liquid absorbed by the liquid retaining material 3 reaches the portion of the vibrating body 2 in contact with the liquid retaining material 3 and is guided to each hole 20 by the capillary phenomenon. When the liquid passes through the holes 20, the passage area of the liquid in each hole 20 decreases from the inlet side to the outlet side thereof, so that the liquid is subjected to the squeezing action by the holes 20 to form fine and uniform particles. And flows out to the outlet side of the hole 20. As a result, the liquid flowing out from the hole 20 is efficiently atomized by the diaphragm action and the elastic vibration of the vibrating portion 13. According to the ultrasonic atomizer of FIG. 1, the frequency is 290.6 kHz when the applied voltage is 10.7V.
The atomization amount becomes maximum at z, and the power consumption at that time is 320
mW, current is 30 mA. The power consumption of the entire device including the power source is 642 mW and the current is 60 mA.

[0022]

According to the ultrasonic atomizing device of the present invention, since the liquid is atomized while passing through the hole provided in the vibrating portion,
The fineness and uniformity of the fog particles can be promoted. Furthermore, since at least a part of the vibrating portion has a curved structure, it is possible to diverge the existence region of the fog. Due to the high atomization efficiency, a large amount of atomization can be realized with low power consumption and the device can be easily downsized. Since self-excited driving is possible and driving with a battery is easy, driving with low power consumption is possible in a form that can respond to environmental changes.

By adopting a simple structure composed of a piezoelectric ceramic and the electrodes formed on both end faces perpendicular to the thickness direction of the piezoelectric ceramic as the piezoelectric vibrator, the device can be downsized and highly efficient. The liquid can be atomized and can be driven with low power consumption.

The piezoelectric ceramic has a through hole penetrating in parallel with the thickness direction of the piezoelectric ceramic, and the shape of the cross section perpendicular to the thickness direction forms a frame type structure, and the length in the thickness direction, By adopting a structure in which the ratio of the shortest distance between the outer edge and the inner edge of the frame type is substantially equal to 1, the coupled vibration of the composite of the piezoelectric vibrator and the vibrating body is enhanced. Therefore, the vibration energy of the piezoelectric vibrator is efficiently propagated to the vibrating body to vibrate the vibrating body and the atomization efficiency is increased. Further, by adopting the annular structure as the frame type, the combined vibration of the composite of the piezoelectric vibrator and the vibrating body is further enhanced, so that the atomization efficiency is further increased.
Further, by adopting a structure in which the vibrating body is provided at a position that covers the opening of the through hole or at least one position inside the through hole, the vibration energy of the piezoelectric vibrator is efficiently propagated to the vibrating body and vibrates the vibrating body. The atomization efficiency can be increased. Further, since the vibrating body is composed of the fixed part fixed to the piezoelectric vibrator and the vibrating part surrounded by the fixed part, the vibrating part performs combined vibration integrated with the piezoelectric vibrator. Therefore, the solution supplied to the vibrating section is atomized by the combined vibration and is emitted as a mist toward the upper side of the vibrating section. The vibration of the vibrating section increases the atomization efficiency of the liquid and increases the amount of fog generated. By using a plurality of vibrators, the fineness of the mist particles can be further improved.

Since the atomization amount increases as the applied voltage increases, the atomization amount can be freely changed by changing the voltage according to the purpose.

A liquid retaining material for sucking up the liquid and supplying it to the vibrating portion is provided as a means for supplying the liquid to the vibrating portion. As the liquid retaining material, sponge or the like has a large liquid absorbing ability and has an acoustic impedance higher than that of the piezoelectric vibrator. By using a low substance, not only can liquid be supplied efficiently without waste, but also the propagation of ultrasonic waves from the piezoelectric vibrator into the liquid is blocked, and the liquid holding material itself for exciting the piezoelectric vibrator is cut off. Is also suppressed, the excitation of the piezoelectric vibrator can efficiently vibrate the diaphragm. Therefore, the atomization efficiency of the liquid is increased, and the large amount of liquid can be atomized with low power consumption.
In addition, downsizing of the device can be easily realized.

By adopting the structure in which the liquid retaining material is brought into contact with the concave portion of the curved structure in the vibrating portion, the liquid supplied to the concave portion passes through the hole provided in the vibrating portion and is projected on the convex portion of the curved structure. Atomized towards. The atomization through the holes not only promotes the fineness and uniformity of the particles, but also can increase the atomization efficiency, as well as diverge the direction of the atomized fog. By adopting a structure in which the liquid retaining material is brought into contact with the convex portion of the curved structure in the vibrating portion, the liquid supplied to the convex portion is directed toward the concave portion of the curved structure while passing through the hole provided in the vibrating portion. Atomized. The atomization through the holes not only promotes the fineness and uniformity of the particles but also increases the atomization efficiency, and can converge the direction of the atomized fog.

Since the opening area of one of the holes provided in the vibrating portion is larger than the opening area of the other, the structure in which one opening is on the inlet side and the other opening is on the outlet side is adopted. As the area decreases from the inlet side to the outlet side of the hole, the liquid is subject to a throttling action by the hole as it passes through the hole. As a result, the atomizing action of the liquid is promoted by the synergistic effect of the throttling action and the vibration of the vibrating portion, the amount of fog generated is increased, and the particle diameter is made uniform.

By adopting a structure in which the resonance frequency of the composite of the piezoelectric vibrator and the vibrating body is substantially equal to the resonance frequency of the single piezoelectric vibrator, the combined vibration of the composite of the piezoelectric vibrating body and the vibrating body is adopted. , The amount of fog generated will further increase.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an ultrasonic atomizing device of the present invention.

FIG. 2 is a perspective view showing a piezoelectric vibrator 1 in the ultrasonic atomizing device of FIG.

FIG. 3 is a plan view of a composite body including a piezoelectric vibrator 1 and a vibrating body 2.

FIG. 4 is a diagram showing a cross section of a vibrating portion 13 that appears when cut along a plane perpendicular to the plate surface.

FIG. 5 is a partially enlarged plan view of a vibrating portion 13.

[Explanation of symbols]

 1 Piezoelectric vibrator 2 Vibrating body 3 Liquid retaining material 11 Piezoelectric ceramic 12 Fixed part 13 Vibrating part 20 Hole

Claims (5)

[Claims] 1. An ultrasonic atomizer for atomizing a liquid by elastic vibration generated by an ultrasonic exciter having a vibrating body fixed to a piezoelectric vibrator, wherein the piezoelectric vibrator includes a piezoelectric ceramic and a piezoelectric ceramic. Electrodes A and B formed on both end surfaces of the porcelain perpendicular to the thickness direction
The piezoelectric ceramic has a through hole that is penetrated in parallel to the thickness direction of the piezoelectric ceramic, the shape of the cross section perpendicular to the thickness direction forms a frame-type structure, the thickness direction And the shortest distance between the outer edge and the inner edge of the frame is substantially equal to 1, and the vibrating body is provided at a position covering the opening of the through hole or at least at one position inside the through hole. And a vibrating portion surrounded by the fixed portion and a vibrating portion surrounded by the fixed portion, wherein the vibrating portion is provided with a number of holes, and at least a part of the vibrating portion has a curved structure. Ultrasonic atomizer characterized by being made. 2. The ultrasonic atomizing device according to claim 1, wherein the frame shape is an annular shape. 3. The means for supplying the liquid to the vibrating portion includes a liquid retaining material that absorbs the liquid and supplies the liquid to the vibrating portion, the liquid retaining material being provided in a concave portion or a convex portion of the curved structure. The ultrasonic atomizing device according to claim 1 or 2, wherein the ultrasonic atomizing device is contacted. 4. The ultrasonic atomizing device according to claim 1, wherein one opening area of the vibrating portion and the other opening area of the hole are different from each other. 5. The supersonic wave according to claim 1, wherein the resonance frequency of the piezoelectric vibrator is substantially equal to the resonance frequency of a composite body of the piezoelectric vibrator and the vibrating body. Sonic atomizer.