JPS6327066B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 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. .

Configurations of Conventional Examples and Their Problems Various types of liquid atomization devices have been proposed in the past, and many of them use electric vibrators such as piezoelectric elements.

For example, (1) a piezoelectric element is bolted or glued to a horn-shaped vibrator, the mechanical vibration amplitude of the piezoelectric element is amplified by the horn-shaped vibrator, and a liquid is supplied and dripped onto the amplitude amplifying surface at the tip of the horn. (2) A device that injects an array of ultrasonic atomized particles, which has been put into practical use in inkjet recording devices in recent years, and has a piezoelectric vibrator installed at one end of the liquid chamber. , with an orifice installed at the other end, the pressure increase in the liquid chamber due to the vibration of the piezoelectric vibrator is transmitted to the orifice via the liquid, and as a result, the orifice can spray atomized particles at a considerable scattering speed. There are atomization devices that can do this.

However, the conventional ultrasonic atomization device described above had various drawbacks.

The atomization device (1) requires high machining precision for the horn-shaped vibrator and a pump to supply the liquid, so it is expensive, and the method of supplying the liquid to the atomization surface is complicated. It was hot. Further, in order to obtain an atomization amount of 20 c.c./min, a considerably large power consumption of 5 to 10 watts is required, and the atomization ability is not sufficient.

The atomizing device (2) had the advantage of being simple in structure and stable in operation, as is clear from the fact that it is used in inkjet. Since the configuration transmits the information to the orifice via the liquid, when a typical liquid containing a large amount of dissolved air is used, cavitation bubbles will occur in the liquid chamber, and these bubbles will prevent stable atomization operation. It had the disadvantage of being unsustainable. Therefore, in order to atomize ordinary liquids, dissolved air must be degassed, which is extremely lacking in versatility.

OBJECT OF THE INVENTION The present invention aims to eliminate such conventional drawbacks, and provides an atomization device that has a compact configuration, obtains a sufficient amount of atomization with low power consumption, and maintains stable atomization operation. For the purpose of providing.

Structure of the Invention In order to achieve this object, the present invention includes a body including a pressurized chamber filled with liquid, a supply section for supplying liquid to the pressurized chamber, and a supply section facing the pressurized chamber. An atomizer is constituted by a nozzle section having a nozzle provided in the nozzle, and an electric vibrator that energizes the nozzle section and vibrates the nozzle, and also detects a current flowing through the electric vibrator. A current detector, an amplifying section that amplifies the signal of the current detector, and an inductor that transmits the signal from the amplifying section to the electric vibrator constitute an atomizing device, The capacitance and the inductor form a self-excited oscillator whose oscillation period of the system is approximately determined.

With this configuration, the electric vibrator forms an electric tank circuit with the inductor, and boosts the voltage supplied to the amplifier section to generate vibrations, which reduces power consumption and also feeds back the signal from the current detector. By amplifying it, a self-excited oscillation system is constructed to automatically track changes in the characteristics of the electric vibrator and maintain stable atomization operation. Furthermore, during actual atomization operation, the pressurized chamber acts as a self-sufficient liquid pump due to the vibration of the nozzle plate, making the atomizer system more compact.

DESCRIPTION OF EMBODIMENTS An atomizer which is an embodiment of the present invention will be described with reference to FIG. A body 2 including a pressurized chamber 1 filled with liquid is fixed to a mounting plate 4 with screws 3. The liquid enters the pressurizing chamber 1 through the supply pipe 5, and the gas discharge pipe 6 is filled halfway during actual atomization. Reference numeral 7 denotes a nozzle portion facing one side of the pressurizing chamber 1, and its outer periphery is joined to the body 2. A spherical protrusion 8 having a fine nozzle for ejecting droplets is formed at the center of the nozzle portion 7 . Furthermore, an annular electric vibrator, here a piezoelectric element 9, is attached to the nozzle portion 7. This piezoelectric element 9 is a piezoelectric ceramic polarized in the thickness direction, and has electrodes on the surface to be joined to the nozzle portion 7 and on the opposite surface. 10 is a lead wire that transmits a drive signal to the piezoelectric element 9;
is soldered to one side of the body 2, and the other side is connected to the body 2 with screws 11. When the mechanical vibration of the piezoelectric element 9 is excited by the drive signal, the nozzle part 7 is also urged and vibrated, and as a result, the liquid in the pressurizing chamber 1 is discharged as atomized particles 12.

Incidentally, the liquid supplied to the pressurizing chamber 1 may be filled halfway into the gas discharge pipe 6 in the atomizer installation configuration, but as an alternative, the liquid supplied to the pressurizing chamber 1 may be and the exhaust pipe 6 is empty, for example, the exhaust pipe 6 is empty before entering the droplet ejection sequence.
Negative pressure may be applied through the pressure chamber 1 to fill the pressurized chamber 1 with liquid, and at the same time, the exhaust pipe 6 may be pulled up halfway.
According to the latter method, impurities in the liquid solidify in the nozzle, and the problem that droplets cannot be ejected does not occur.

Next, referring to FIG. 2, the driving configuration of the atomizer shown in FIG. 1 will be explained. Reference numeral 13 denotes an amplifying section that amplifies a signal from a current detector 14 that detects the current flowing through the electric vibrator 9, and transmits a drive signal to the electric vibrator 9 via an inductor L15.

Furthermore, FIG. 3 is an electrical equivalent circuit that approximates the electrical vibrator 9, with 16 equivalent parallel capacitances C _S
, 17, 18, and 19, each consisting of a series inductance L ₀ , a capacitance C ₀ , and a resistance R ₀ . Inductor L15 in Figure 2 has an equivalent parallel capacity
A series resonance configuration with C _S as the main component is selected, and the resonance frequency is selected to be lower than the resonance frequency of the atomizer. With this L
A tank circuit is formed by _CS , and the drive voltage transmitted from the amplifier 13 is boosted across the electric vibrator 9. Therefore, the oscillation frequency of the drive circuit system determined by L and C _S is set slightly lower than the resonant frequency of the atomizer, and the system as a whole consumes less power and can achieve efficient and stable liquid spray. It becomes possible.

Here, the reason why the frequency of the self-oscillation system determined mainly by L and C _S is set lower than the resonance frequency of the atomizer will be explained with reference to FIG. 4. Figure 4a shows the relationship between frequency and current when a driving voltage is applied to the electrical vibrator 9 without going through the inductor L, where = _r is the electrical resonance frequency, = _ar
represents the electrical anti-resonance frequency. = _n is _r
As is clear from the relationship between the frequency and the atomization amount shown in Figure _b , this is the point where the atomization amount is maximum, and is the mechanical resonance point of the atomizer. It is most efficient to excite the electrical vibrator at this mechanical resonance point. However, when exciting using a self-oscillation method with a simple configuration, when the oscillation frequency approaches the resonant frequency, a sudden jump in frequency and power occurs, and stable oscillation may not be achieved.
In order to avoid this pull-in phenomenon, it is necessary to make the coupling with the drive stage output section sufficiently loose, and the coupling circuit for this requires a complicated configuration and also reduces efficiency. Therefore, as described above, if self-oscillation is performed at a frequency lower than the resonance point, for example, at a point slightly lower than _r , a large amount of atomization can be ensured, and stable oscillation can be maintained.

FIG. 5 shows a specific embodiment of the present invention. The same numbers as in the previous figure indicate components having the same function. Reference numeral 20 denotes a resistor constituting a current detector, and this detection signal is sent via a capacitor 21 to a combinational SEPP type amplifier circuit, and is transmitted via an inductor 15 by the operation of switching transistors 32 and 33 in the output stage. and is transmitted to the electric vibrator 9. The amplifier circuit includes resistors 22, 2
3, 24, 25, 27, 29, 30, transistors 26, 31, 32, 33, and capacitor 28
It is composed of. This closed loop forms a self-excited oscillation circuit system with an oscillation period determined by L and C _S . Note that since the output stage performs a switching operation, the loss of the transistor itself is small, and the power consumption of the amplifier section is also reduced. Although this specific embodiment is a combinational structure, for example, a configuration may be adopted in which only a switching element is provided for discharging charges from the _LCS .

Effects of the Invention According to the atomization device of the present invention, the following effects can be obtained.

(1) In addition to the compact configuration of the atomizer itself, the power consumption of the drive device is reduced, and the atomizer can achieve lower power consumption, that is, higher efficiency.

(2) Configure an oscillation system that is approximately determined by the equivalent parallel capacitance C _S that changes according to the rate of change in the mechanical resonance point due to the temperature characteristics of the electrical vibrator, and the inductor L that has small temperature characteristics. And, moreover,
Since the frequency is set to be stable for a self-excited oscillation system, the amount of atomization can be ensured, and automatic frequency tracking can be realized with a simple configuration.

(3) By simply adjusting the inductance, the self-excited oscillation frequency can be set lower than the resonance point, so it is possible to prevent the pull-in phenomenon, maintain stable oscillation, and use it as an atomizer. A large quantity can also be secured.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part of an embodiment of the present invention, Fig.
The figure is a block diagram showing the configuration of an atomizing device according to an embodiment of the present invention, FIG. 3 is an electrical equivalent circuit diagram of a piezoelectric element, FIG.
FIG. b is a diagram showing the relationship between the driving frequency and the amount of atomization, and FIG. 5 is a circuit diagram of the same. DESCRIPTION OF SYMBOLS 1... Pressurization chamber, 2... Body, 5... Supply part, 7... Nozzle part, 9... Electric vibrator, 14
...Current detector, 13...Amplification section, 15...Inductor.

Claims (1)

[Claims] 1 A body equipped with a pressurized chamber filled with liquid,
a supply unit for supplying liquid to the pressurizing chamber; a nozzle unit having a nozzle facing the pressurizing chamber; and an electric vibrator that biases the nozzle unit and vibrates the nozzle. an atomizer comprising: a current detector that detects the current flowing through the electric vibrator of the atomizer; an amplifier that amplifies the signal of the current detector; and an equivalent capacitance of the electric vibrator. and an inductor that substantially determines the oscillation period of the system, and the oscillation frequency of the self-excited oscillator is set lower than the resonance frequency of the electric vibrator.