JPS6051571A - Atomizing apparatus - Google Patents

Abstract

PURPOSE:To always drive the titled apparatus with good efficiency by allowing an electrical vibrator to automatically follow the change of a resonant point, by negating the equivalent capacity component of an atomizer in which the electrical vibrator is assembled while constituting a self-oscillation system due to a series resonance signal. CONSTITUTION:A liquid enters the pressure chamber 14 of a body 15 through a supply part 18 and a nozzle part 20 having a nozzle provided so as to be confronted to the chamber 14 is vibrated by an electrical vibrator 22 to atomize the liquid in the chamber 14. Herein, the current of the primary side of a transformer 29 connected to the secondary side of a piezoelectric element 9 is detected by a detection part 28 and the signal thereof is amplified by an amplifier 13 to be transmitted to the element 9 through the transformer 29. This automatic oscillation circuit always succeeds oscillation in the vicinity of the mechanical resonant point of the element 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid atomization device that atomizes liquid fuel such as kerosene or light oil, water, medicinal solution, recording liquid, etc. using an electric vibrator.

4! '1 Conventional configuration and its problems Various types of liquid atomization devices have been proposed in the past, and many ultrasonic atomization devices using electric vibrators such as piezoelectric elements are also seen. A means for efficiently driving the pressure Tii element near its mechanical resonance point has also been proposed.

First, FIG. 1 shows an electrical equivalent circuit of a generally used piezoelectric element, which includes a series circuit section consisting of an inductance L1 of 1, a capacitance C1 of 2, a resistance R1 of 3, and a capacitance C0 of 4. It consists of an η valence sequence capacitive part. Figure 2 shows the reactance characteristics of a normal piezoelectric element with respect to frequency, where f (f r is capacitive, f r
( f ( f a r is inductive, f a r ( f
It also shows capacitance. It can be seen that fr and far are called a resonant frequency and an anti-resonant frequency, respectively, and when f=fr, the impedance becomes a pure resistance component R1.

FIG. 3 shows a piezoelectric element having the basic characteristics as shown in FIG. 2, or a basic oscillation driving means for an atomizer incorporating a piezoelectric element. In the same figure (at is the prototype of the Colpitts oscillator circuit, which consists of a transistor 5, a capacitor 6.7, and a coil/l/8. (bl is the coil/l/8 described above.
8 is replaced with a piezoelectric element 9, and oscillation continues in the frequency range in which the piezoelectric element 9 acts as an inductor 77, that is, f r (f (f a r) in FIG. 2.

At this time, oscillation occurs at the mechanical resonance point, and oscillation is achieved with high efficiency and at the optimum driving frequency.

However, it does not have a region that acts as an inductance,
The basic Colpitts oscillation circuit as described above cannot be applied to an atomizer that uses a piezoelectric element that exhibits capacitive characteristics in the vicinity of the resonance point of actual atomization. Driving means for such an atomizer include (1) means for applying a predetermined drive frequency to the piezoelectric element using an external oscillation circuit and changing the frequency according to temperature characteristics, and (2) means for changing the frequency by adjusting the capacitance of the atomizer. Use your nature,
Conventionally, it has been proposed to arrange an inductance that resonates in series with this capacitance, extract the resonance signal, and feed it back to the amplifier to form a self-oscillating string.

FIG. 4 is a configuration diagram showing the conventional example (2) mentioned above, in which a signal is transmitted to the piezoelectric element 9 via an inductance 10.

Reference numeral 11 denotes a resistor for detecting resonance current, and this detection signal is transmitted to an amplifier 13 via a capacitor 12 for cutting a DC component, and the amplified signal is applied to the piezoelectric element through the inductor 10 described above. With this self-oscillation system,
A predetermined drive frequency signal is transmitted to the atomizer, and atomization is performed.

However, the examples (1) and (2) above do not have a configuration that reliably tracks and oscillates the series resonance point (fr=1〒) of the piezoelectric element shown in Fig. 1. However, it also had the disadvantage of not being able to compensate for shifts in the mechanical resonance point due to environmental changes such as temperature or changes over time.

Purpose of the Invention The present invention aims to eliminate such conventional drawbacks by canceling out the equivalent capacitance of the atomizer that exhibits capacitance near the resonance point of use, and outputting a series resonance signal to achieve self-excitation. We provide a simple atomization device that configures an oscillation system and tracks the mechanical resonance point that maintains a stable atomization state and can be driven efficiently at all times in response to changes in the resonance point due to changes in the external environment or changes over time. 1-1.

Structure of the Invention In order to achieve this object, the present invention includes a body provided with a pressurized chamber filled with a liquid as a load, a supply section for supplying liquid to the pressurized chamber, and a an atomizer consisting of a nozzle part having a nozzle facing the front; an electric vibrator that energizes the nozzle part to vibrate the nozzle /1; a transformer connected to the primary side of the transformer; It is equipped with an amplifying section that transmits the signal to the electric vibrator through the electric vibrator.

With this configuration, the primary inductance of the transformer cancels out the equivalent sequence capacitance of the atomizer incorporating the electric vibrator, and a self-excited oscillation circuit based on the internal series resonance signal can be constructed.

DESCRIPTION OF EMBODIMENTS An atomizer which is an embodiment of the present invention will be described with reference to FIG. A body 15 including a pressurized chamber 14 filled with liquid is fixed to a mounting plate 17 with pins 16. The liquid enters the pressurizing chamber 14 through the supply pipe 18, and during the atomization operation, the gas discharge pipe 19 is filled halfway. 20
A nozzle portion is arranged facing one side of the pressurizing chamber 14, and its outer periphery is joined to the body 15. A spherical protrusion 21 having a fine hole for ejecting droplets is formed in the center of the nozzle portion 20 . Furthermore, an annular electric vibrator, here a piezoelectric element 22, is attached to the nozzle portion 20. This piezoelectric element 22 is a piezoelectric ceramic polarized in the thickness direction, and has electrodes on the surface to be joined to the nozzle and on the opposite surface.

23 is a lead wire that transmits a drive signal to the piezoelectric element 22;
One side is soldered to one electrode surface of the piezoelectric element 22, and the other side is connected to the body 15 with a helix 24. When the mechanical vibration of the piezoelectric element 22 is excited by the drive signal, the nozzle part 20 is also energized and vibrates, so that as a result, the liquid in the pressurizing chamber 14 is discharged as atomized particles 25. .

By the way, the liquid supplied to the pressurizing chamber 14 may be filled halfway into the gas discharge pipe 19 in an atomizer installation configuration, but as an alternative, the pressurizing chamber is usually empty and liquid droplets are filled. Before entering the discharge sequence, negative pressure is applied through the exhaust pipe 19 to fill the pressurized chamber 14 with liquid and the exhaust pipe 1
You may raise it to the middle of 9. According to the latter means,
This eliminates the problem of impurities in the liquid being assimilated in the nozzle hole and not being able to eject all droplets.

FIG. 6 is a diagram showing the relationship between the frequency ■ of the atomizer of the present invention and the upstream I, where f = f r IcIM<mermaid, f =
There is a minimum point in far. Each point is a point where series resonance and parallel resonance occur in the electrical equivalent circuit shown in FIG. The actual amount of spray reaches its maximum value at the midpoint between (γ and faγ. That is, the spray can be most efficiently achieved at the mechanical resonance point (frm).

FIG. 7 shows the leading phase of current with respect to voltage when the atomizer of the present invention is driven. Although the phase difference is minimum at the mechanical resonance point frm, the current is all in the leading phase.
That is, it exhibits the characteristic of phagocytosis.

FIG. 8 shows a block configuration of a circuit that provides a signal from the external oscillator 26 via the amplifier 13 to an inductance 27 connected in parallel with the piezoelectric element 9. 28 is a resistor for detecting a signal connected to the piezoelectric element 9 and the inductance 27, and 2o is its output signal. inductance 2
The value of 7 is selected so that it resonates in parallel with the equivalent parallel capacitance near the mechanical resonance point of the piezoelectric element.

FIG. 9 is a frequency characteristic diagram of the configuration shown in FIG. 8, in which the horizontal axis represents the drive frequency and the vertical axis represents the output signal v0. A
1 is the characteristic with the configuration as shown in FIG. 8, and there is a peak value at frm, but the output signal v0 becomes large at both low and high frequencies. A2 is the 8th
■ Output signal in figure.

is passed through a bandpass filter (B, P, F,) with a center frequency near f=frm, and it can be seen that the signal near the resonance point shows a maximum value in a predetermined frequency region.

FIG. 1'0 shows a drive circuit for atomization 1ri according to an embodiment of the present invention. Parts with the same numbers as those in FIG. 8 are components having the same functions. 29 is a transformer, and the electric vibrator 9 is connected to the secondary side. The current flowing to the primary side of 1) if transformation 2;) is detected by the current detection section 28, and is transmitted to the amplification section 13 via the DC cut capacitor 30. Considering the impedance of the electrical oscillator 9 converted to the primary side of the transformer 290, the square of the turns ratio of the equivalent sequence capacitance C0 resonates in parallel with the primary inductance of the transformer and is canceled out. The self-excited oscillation circuit shown in FIG. 10 oscillates mainly due to the series resonance signal caused by L 1 y C1.

With this circuit configuration, the self-excited oscillation circuit always continues to oscillate near the mechanical resonance point of the electrical vibrator.

Further, since the electric vibrator is connected through the transformer, the drive circuit section and the electric vibrator are electrically insulated. That is, in the atomizer which is an embodiment of the present invention shown in FIG. 5, one of the electrodes of the electric vibrator has the same potential as the main body of the device, but as mentioned above, it is insulated from the drive circuit section. Therefore, there is no need for complicated circuit configurations for signal processing, such as flame loradons, which are connected to electrical components that are at the same potential as the main body of the device.

FIG. 11 is a diagram showing another embodiment of the present invention. 3
1 is a bandpass filter, which makes it easy to extract signals near the mechanical resonance point of the electric vibrator. Other parts with the same numbers as above are components having the same functions.

Effects of the Invention According to the atomizing device of the present invention, the primary inductance of the transformer connected to the electric vibrator on the secondary side cancels out the equivalent parallel capacitance of the vibrator, thereby reducing the mechanical resonance of the atomizer. It becomes possible to construct a self-oscillation system with a simple configuration that only requires the resonant signal to be extracted and the resonant signal is fed back to the amplifier. This has the effect that fluctuations in the mechanical resonance point due to external environmental conditions or changes over time can be automatically tracked, and tilting can be driven efficiently.

Furthermore, since the electrical vibrator is connected through the transformer, electrical isolation in relation to other circuit systems is simplified.

[Brief explanation of drawings]

Fig. 1 is an electrical equivalent circuit diagram of a piezoelectric element, Fig. 2 is a diagram showing the reac-cunnu characteristic of a piezoelectric element with respect to frequency changes, Fig. 3 (a) is a basic circuit diagram of a Colpitts type oscillator circuit, and (bl is Pierce circuit diagram incorporating a piezoelectric element, Figure 4 is a conventional oscillation circuit diagram, Figure 5 is a ν) front view of an atomizer that is an embodiment of the present invention, and Figure 6 is a diagram of the same atomizer. Characteristics of driving frequency and current Figure 1. Figure 7 shows the phase relationship between the current and voltage of the atomizer. Figure 8 shows the frequency when an inductance is connected in parallel with the piezoelectric element of the atomizer. Characteristic measurement circuit diagram,
FIG. 9 shows the determination of the frequency t1 in the measurement circuit of FIG.
FIG. 10 is a circuit diagram of an atomizer showing one embodiment of the invention, and FIG. 11 is a circuit diagram of an atomizer showing another embodiment of the invention. 13... Amplifying section, 14... Pressurizing chamber, 1
5...Body, 18...Supply section,
20... Nozzle part, 22... Electric vibrator, 28... Current detection part, 29...
Metamorphosis 8L31...Name of bandpass filter agent Patent attorney Satoshi Nakao Male +) A\1 person Figure 1 Δ Figure 2 Figure 4 Figure 3

Claims (1)

[Claims] (1) A body including a pressurized chamber filled with liquid, a supply section for supplying liquid to the pressurized chamber, and a nozzle provided facing the pressurized chamber. an atomizer consisting of a nozzle part and an electric vibrator that energizes the nozzle part to vibrate the +jiJ diary nonu melody; and a transformer 21' in which the electric vibrator is connected to the secondary side. , 1: + A current detection section that detects the current flowing to the primary side of the metamorphic g3, and amplification of the signal of the current detection section. L! A device consisting of an amplifying section (2l) that transmits the signal from the current detecting section to the amplifying section via a predetermined amplifier;'1゜31
The atomizing device according to item 1, wherein the range is 1J. (3) Equivalent sequence capacity of the electric oscillator and the transformer 1
The atomizer according to claim 1, wherein the parallel resonance frequency determined by the self-inductance of the next winding is made substantially equal to the mechanical resonance frequency of the electric vibrator.