JPH067722A - Ultrasonic spraying apparatus - Google Patents

Abstract

PURPOSE:To make the ultrasonic spraying apparatus satisfactory in terms of all respects as spraying efficiency, a large amt. of spraying, fineness and uniformity of the sprayed particle and cost of a driving electric source. 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 converged as the central part of the oscillating body 2 is curved upward into a concave shape. A simple and lightweight structure can be obtd. thereby and spraying efficiency, a large amt. or spraying and fineness and uniformity of the sprayed particle can be improved thereby, too and the direction of spraying can be 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 faces perpendicular to the thickness direction of the piezoelectric ceramic, and the vibrating body is the piezoelectric vibrator. Of the electrode A or B, which are integrally fixed to the end face having the electrode A or B, and which are fixed to the piezoelectric vibrator, and a vibrating part which projects outward from the piezoelectric vibrator. The vibrating part is provided with a large number of holes, at least a part of the vibrating part has a curved structure, and the means for supplying the liquid to the vibrating part absorbs the liquid and A liquid retaining material supplied to the vibrating section, Liquid material is characterized in that it is in contact with the convex portion of the curved structure.

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

[0006]

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 is composed of a piezoelectric ceramic and electrodes A and B formed on both end faces perpendicular to the thickness direction of the piezoelectric ceramic. 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 vibrating body is the electrode A of the piezoelectric vibrator.
Alternatively, since the vibrating portion vibrates in such a manner that the vibrating portion serves as a fixed end by being integrally fixed to at least one end surface having B, the liquid supplied to the vibrating portion is It is atomized by elastic vibration and is emitted as mist toward above the vibrating part.

The means for supplying the liquid to the vibrating section is
A liquid retaining material is provided to absorb the liquid and supply the liquid to the vibrating section. Since the liquid retaining material is in contact with the convex portion of the curved structure in the vibrating portion, the liquid supplied to the convex portion is fogged toward the concave portion of the curved structure through the hole provided in the vibrating portion. Be converted. The atomization through the holes not only promotes the fineness and uniformity of the particles but also increases the atomization efficiency, and the atomized fog can be concentrated in a part of the space.

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.

[0011]

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 convex portion of the vibrating body 2, and supplies liquid from the liquid retaining material 3 to the convex portion during use.

FIG. 2 is a side view showing an embodiment of a composite body composed of the piezoelectric vibrator 1 and the vibrating body 2, and FIG. 3 is a plan view of the composite body of FIG. The piezoelectric vibrator 1 is a piezoelectric ceramic 11 having a rectangular plate shape.
The material of the piezoelectric ceramic 11 is TDK72A material (product name), the length is 10 mm, the width is 9 mm, and the thickness is 1 m.
m. Since the TDK72A material has a large electromechanical coupling coefficient, it is used in this example. Piezoelectric ceramic 11
The direction of the polarization axis of is coincident with the thickness direction, and electrodes D, F and G are formed on both end faces perpendicular to this thickness direction. The electrodes D and F are provided on the same surface and are insulated from each other. The electrode D covers a portion of the piezoelectric ceramic 11 which is located 4.5 mm from the end in the lengthwise direction, and the electrode F is separated from the electrode D by 1 mm.
It covers the rest, mm apart. Terminal P for electrode D
, The terminal Q is attached to the electrode F, and the terminal R is attached to the electrode G. A tongue-shaped vibrating body 2 having a curved central portion is attached to one end surface of the piezoelectric vibrator 1. The vibrating plate 2 is made of nickel, and is fixed integrally with the piezoelectric vibrator 1 in the long and thin plate-shaped fixing portion 12, and the vibrating body 2 of the portion protruding from the piezoelectric vibrator 1 forms the vibrating portion 13. ing. The fixed portion 12 is adhered to the piezoelectric vibrator 1 via the electrode F with an adhesive. The vibrator 2 has a length of 10.5 mm, a width of 9 mm, and a thickness of 0.
It is 05 mm. The fixed part 12 has a length of 1.5 mm and a width of 9 m.
m and the thickness is 0.05 mm. The vibrating portion 13 projects outward from an edge portion along the width direction of the piezoelectric vibrator 1.
The vibrating part 13 is 9 mm long, 9 mm wide, and 0.05 mm thick.
Is.

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, when an AC signal having a frequency substantially equal to the resonance frequency of the composite of the piezoelectric vibrator 1 and the vibrator 2 is applied to the piezoelectric vibrator 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. Since the structure in which the vibrating body 2 is integrally connected and fixed to at least one end surface of the piezoelectric vibrator 1 is adopted, the vibrating body 2 is accompanied by the excitation of the piezoelectric vibrator 1.
Is vibrated with the fixed portion 12 as a fixed end, and the elastic vibration of the vibrating portion 13 effectively functions 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 each hole 20, the liquid passing area of each hole 20 decreases from the inlet side toward the outlet side, so that the liquid flows through the holes 2
The particles are subjected to the throttling action by 0, and become fine and uniform particles that flow 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. Since the central portion of the vibrating portion 13 is curved, it is possible to converge the mist ejection direction.

FIG. 6 is a diagram showing frequency characteristics of amplitude and phase of admittance between the electrodes D and G in the composite body of the piezoelectric vibrator 1 and the vibrating body 2. In FIG. 6, the dotted line shows the characteristics of the piezoelectric vibrator 1 alone, and the solid line shows the characteristics of the composite body of the piezoelectric vibrator 1 and the vibrating body 2. When the main resonance points of the piezoelectric vibrator 1 alone are f1, f2, and f3, it can be confirmed that two resonance points fa and fb are newly generated between f2 and f3 in the composite. fo indicates the frequency at which the atomization amount becomes maximum. Although fo is 231 kHz and substantially coincides with the resonance point fb of the composite, fb shifts to the high frequency side as the length of the vibrating portion 13 is shortened. The maximum atomization effect is obtained when this fb exists near f3 and the amplitude of the phase change becomes maximum. By adopting such a structure that the resonance frequency in the composite of the piezoelectric vibrator and the vibrating body is substantially equal to the resonance frequency of the single piezoelectric vibrator, the coupling of the composite of the piezoelectric vibrator and the vibrating body is achieved. Since the vibration is enhanced, the amount of fog generated is further increased.

FIG. 7 shows the relationship between the length of the vibrating portion 13 and the height of the mist when the length of the vibrating portion 13 is changed in the composite body of the piezoelectric vibrator 1 and the vibrating body 2. It is a characteristic diagram. However, the height at this time represents the height from the highest point of the bending portion of the vibrating portion 13. When the length of the vibrating part 13 was 9 mm, the height of the fog reached a maximum value of 55 cm.

FIG. 8 is a characteristic diagram showing the relationship between the length of the vibrating portion 13 and the atomization amount when the length of the vibrating portion 13 is changed in the composite body of the piezoelectric vibrator 1 and the vibrating body 2. Is. When the length of the vibrating part is 9 mm, the atomization amount is 578 cc
The maximum value of / h is reached.

FIG. 9 is a characteristic diagram showing the relationship between the length of the vibrating portion 13 and the power consumption when the length of the vibrating portion 13 is changed in the composite body of the piezoelectric vibrator 1 and the vibrating body 2. is there. Power consumption is almost 1 when the length of the vibrating part is 9 mm.
It was W.

[0020]

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

By adopting a structure in which the vibrating body is integrally fixed on at least one end surface of the piezoelectric vibrator, the vibrating portion vibrates with the fixed portion serving as a fixed end. The supplied liquid is atomized by its elastic vibration and is emitted as mist toward the upper part of the vibrating portion.

As the applied voltage increases, the atomization amount also increases. Therefore, 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 acoustic impedance is 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 convex portion of the curved structure in the vibrating portion, the liquid supplied to the convex portion passes through the hole provided in the vibrating portion and the concave portion of the curved structure is formed. Is atomized towards. 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. Further, by making the opening area on the outlet side into two kinds, it is possible to generate a fog having particles of two kinds of sizes.

[Brief description of drawings]

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

FIG. 2 is a side view showing an embodiment of a composite body including a piezoelectric vibrator 1 and a vibrating body 2.

FIG. 3 is a plan view of the composite body of FIG.

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.

FIG. 6 is a diagram showing frequency characteristics of admittance amplitude and phase in a composite body including the piezoelectric vibrator 1 and the vibrating body 2.

FIG. 7 is a characteristic diagram showing the relationship between the length of the vibrating portion and the height of mist ejection when the length of the vibrating portion is changed in the composite body including the piezoelectric vibrator 1 and the vibrating body 2.

FIG. 8 is a characteristic diagram showing a relationship between the length of the vibrating portion and the atomization amount when the length of the vibrating portion is changed in the composite body including the piezoelectric vibrator 1 and the vibrating body 2.

FIG. 9 is a characteristic diagram showing the relationship between the length of the vibrating portion and the power consumption when the length of the vibrating portion is changed in the composite body including the piezoelectric vibrator 1 and the vibrating body 2.

[Explanation of symbols]

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soichi Yokoyama 6-13-11 Sotokanda, Chiyoda-ku, Tokyo Mikuni Co., Ltd.

Claims (2)

[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 vibrating body is integrally and integrally fixed to at least one end surface of the piezoelectric vibrator having the electrode A or B, and a fixing portion fixed to the piezoelectric vibrator, The vibrating portion protruding outward of the piezoelectric vibrator, the vibrating portion is provided with a number of holes, at least a part of the vibrating portion has a curved structure, the vibrating portion to the An ultrasonic atomizing device, wherein the liquid supplying means includes a liquid retaining material that absorbs the liquid and supplies the liquid to the vibrating portion, and the liquid retaining material is brought into contact with the convex portion of the curved structure. . 2. 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.