JPS59222247A - Atomizing apparatus using ultrasonic wave - Google Patents

Abstract

PURPOSE:To increase the quantity of atomized product of a humidifier and to generate much mist of fine particle size by converging the energy of ultrasonic wave generated by a piezoelectric oscillator by dividing the energy to plural fluxes. CONSTITUTION:A piezoelectric oscillator 3 comprises an electrode 13 covering the whole surface of a piezoelectric electrode 17 at one side 2 contacting with the liquid to be atomized, and >=2 partial electrodes 14, 15, 16 provided to the opposite side. When a driving high frequency voltage is impressed simultaneously from an oscillating circuit 4 to between the electrode 13 and 14, 13 and 15, 13 and 16, ultrasonic wave energy can be converged by dividing to each part corresponding to the position of the electrodes 14, 15 and 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention 1 relates to an ultrasonic atomization device that uses a piezoelectric vibrator as an ultrasonic generation source, and provides a device that can generate a large amount of mist with as small particles as possible. The purpose is to

As is well known, an ultrasonic atomizer atomizes a liquid by using ultrasonic energy emitted toward the surface of the liquid from an ultrasonic vibrator attached to the bottom of a liquid tank. The most widely used ultrasonic humidifier.

A piezoelectric vibrator is generally used as the ultrasonic vibrator, and the ultrasonic atomization device in this case is constructed as shown in FIG. In FIG.

1 is a liquid tank containing the atomized liquid, 2 is the liquid to be atomized, 3 is a piezoelectric vibrator attached to a part of the liquid tank 1,
4 is an oscillation circuit that drives the piezoelectric vibrator 3, 6 is a liquid column generated on the liquid surface by ultrasonic waves, 6 is a fog generated by ultrasonic waves, and 7 is a wind for sending out the fog to the outside. Reference numeral 8 indicates a supply port for supplying the atomized liquid, and reference numeral 9 indicates a nozzle for blowing out the mist.

The ultrasonic frequency in an ultrasonic humidifier configured in this way is generally about 1.7 MHz, the particle size of the emitted mist is 3 to 2011 m, and the amount of atomization is 40 MHz per hour.
0-500 CC is normal.

It is necessary to make the atomization capacity (humidification capacity) of such an atomization device as large as possible, but since large-sized mist does not evaporate in the air and falls, wetting the area where the humidifier is installed, it is necessary to make the particle size as large as possible. It is necessary to generate a large amount of small mist.

The piezoelectric vibrator in a conventional ultrasonic atomizer is constructed as shown in Fig. 2, and an oscillation circuit is installed between the entire surface electrode 1o on the side that comes into contact with the liquid 2 and the partial electrode 11 on the opposite side. 4 is applied, and ultrasonic waves are emitted into the liquid by vibration in the thickness direction of approximately 1.7 MHz.

By the way, in order to improve the atomization ability of the above-mentioned ultrasonic atomizer, it is necessary to increase the driving power of the piezoelectric vibrator 3 to increase the ultrasonic energy, or to focus the ultrasonic waves as much as possible using a horn effect or the like. It is necessary to take measures such as However, in either method, the proportion of mist with large particle sizes increases, which is disadvantageous. Also, to reduce the particle size of fog, it is possible to increase the ultrasonic frequency,
In this case, since the atomization efficiency is reduced, there is a problem in that the atomization ability is significantly reduced. As described above, improving the atomization ability and reducing the particle size of the mist have contradictory conditions, and it has been difficult to achieve both.

In particular, when atomizing liquid, the degree of focusing of the ultrasonic energy generated from the piezoelectric vibrator has its own optimum value in terms of the particle size of the mist and the bone where the mist is generated, and the proportion of the mist with small particle size In order to increase the ultrasonic energy, the degree of focus of the ultrasound energy must be lower than the point where the fog generator reaches its maximum. However, in the conventional piezoelectric vibrator 3 as shown in FIG. 2, when the degree of focusing of ultrasonic energy is lowered, the amount of atomization decreases.
It is not possible to simultaneously increase the amount of atomization and increase the proportion of mist with small particle sizes.

Therefore, in the present invention, as a piezoelectric vibrator to be used, the ultrasonic energy generated from one piezoelectric vibrator is not focused into one, but is divided into multiple parts and focused.
The amount of atomization is increased and a large amount of mist with small particle size can be generated. Hereinafter, an embodiment of the present invention will be explained in detail with reference to FIGS. 3 and 4 showing one embodiment of the present invention.

The piezoelectric vibrator 3 of this example is provided with an electrode 13 on the entire surface of the piezoelectric ceramic 16 on the side that is in contact with the atomized liquid 2, and on the opposite side, two or more partial electrodes 14, 15°6. 16 are provided. Note that 12 is an electrode 130
This is the turning part to the opposite side. And electrodes 13 and 14
．． 13 and 15. By simultaneously applying a driving high frequency voltage from the oscillation circuit 4 between 13 and 16, the electrodes 14, 15
．． Ultrasonic energy can be divided and focused on portions corresponding to 16 positions, respectively. The degree of convergence of each ultrasonic wave is set so that the proportion of mist with small particle size increases.

With this configuration, it is possible to increase the I'l: ratio of mist having a small particle size compared to the conventional piezoelectric vibrator, and to increase the driving power of the piezoelectric vibrator 3. Therefore, the amount of atomization can also be increased.

Figures 3 and 4 show partial electrodes 14.16 on the side opposite the liquid.
．． This is the case where there are two and three 16s, but it goes without saying that there may be more.

The degree of focus of the ultrasonic energy focused on the position corresponding to each partial electrode 14, 15, 16 is different from that of the partial electrode 14.
, 15, 16 and the piezoelectric vibration 6 can be adjusted by a horn installed on the side of the liquid 2 of the horn 3. It can be constructed with a rubber backing or the like that can hold several parts.

FIG. 5 shows an example of a rubber backing 20 having a horn effect and used for mounting the piezoelectric vibrator 3 shown in FIG. 3. Fifth
In the figure, reference numeral 18.19 is an ultrasonic emission port facing the electrode 14.15 in FIG.

Figure 6 shows a comparison of the mist particle size distribution when the piezoelectric vibrator 3 according to the present invention is used (Figure 6b) with that when a conventional piezoelectric vibrator is used (Figure 6a). It can be seen that as the maximum particle size becomes smaller, the proportion of mist with larger particle sizes decreases. It is also possible to obtain the same effect as the piezoelectric vibrator 3 of the present invention by using a plurality of conventional piezoelectric vibrators, but it is more cost-effective to use the piezoelectric vibrator of the present invention. Even if the ultrasonic energy is divided into multiple parts, the phase of each ultrasonic wave can be aligned.
Another effect is that the atomization efficiency can be increased.

As described above, according to the present invention, it is possible to obtain an ultrasonic atomization device that can generate a large amount of mist with small particle size.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the general structure of an ultrasonic atomizer;
FIGS. 2a and 2b are a plan view and a sectional view of a piezoelectric vibrator used in a conventional ultrasonic atomization device, respectively, and FIGS. 3a and 4b are an embodiment of the present invention. FIG. 5a is a plan view and a cross-sectional view of a piezoelectric vibrator used in an ultrasonic atomization device according to . b is a plan view and a cross-sectional view of the rubber backing used for mounting the piezoelectric vibrator shown in Fig. 3, and Figs. 6 a and b, respectively.
1 is a particle size distribution diagram of fog when using piezoelectric vibrators according to a conventional method and an embodiment of the present invention. 1...Liquid tank, 2...Liquid, 3...
・Piezoelectric vibrator, 6...mist, 13...electrode, 14,15.16...partial electrode, 17...
...Piezoelectric ceramic, 18.19...Radiation port, 2
o...Rubber backing. Name of agent: Patent Attorney Toshio Tsuchinakao and 1 person Figure 3 @ Figure 1 Figure 2 Figure 4 Figure 6 Figure 5 Figure 6 α

Claims (2)

[Claims] (1) A piezoelectric vibrator is attached to a part of the liquid tank containing the liquid to be atomized, and electrodes are provided on the entire surface of the piezoelectric vibrator on the side that comes into contact with the atomizing liquid, and multiple electrodes are provided on the opposite side. An ultrasonic atomizer characterized in that a partial electrode for driving a piezoelectric vibrator 1 is provided. (2) The ultrasonic atomization device according to claim 1, which has a multifaceted shape and has three or more drive partial electrodes provided on the side of the piezoelectric vibrator opposite to the atomization liquid.