JPS6125900Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ultrasonic atomization device that vibrates a vibrator at a high frequency and uses the vibrator to emit ultrasonic waves into a liquid to atomize the liquid. An object of the present invention is to provide an ultrasonic atomizer capable of keeping the amount of atomization constant even if the magnitude of voltage changes.

What is an ultrasonic atomizer? A vibrator attached to the bottom of the liquid to be atomized is driven by an oscillation circuit, and the liquid is atomized into fine particles by emitting ultrasonic waves above the liquid surface. It is something. Recently, demand for such ultrasonic atomization devices has been increasing for use in humidification and atomization of chemical solutions.

The basic circuit of a conventional ultrasonic atomizer is shown in FIG. In Figure 1, 1a and 1b are single-phase AC power input terminals, 2a, 2b, 2c, and 2d are diodes that constitute a rectifier circuit, 3 is a capacitor for noise removal, 4 is an output terminal of the rectifier circuit, 5 and 6 is a voltage dividing resistor that applies a bias voltage to the base of transistor 7. 8, 9, and 10 are capacitors, 11 is a resistor, and 12 is a vibrator, which constitute a Colpitts oscillation circuit. 13 is a chiyoke coil provided in the oscillation circuit. 14 is a terminal on the collector side of the transistor 7.

In the circuit configured as described above, an AC voltage shown in FIG.
Full-wave rectification is performed by a rectifier circuit consisting of d as shown in FIG. 2b. In other words, capacitor 3 is 0.02μF
It has a relatively small capacity and is provided for the purpose of removing noise from the oscillation circuit side.
The full-wave rectified waveform voltage shown in FIG. 2b appears as is at the output terminal 4 of the rectifier circuit. Furthermore, a high frequency voltage generated by an oscillation circuit composed of the transistor 7, capacitors 8, 9, 10, a resistor 11, and a vibrator 12 is applied to the terminal 14 on the collector side of the transistor 7 at the power supply voltage shown in FIG. 2b. A modified voltage waveform as shown in FIG. 2c appears. Vibrator 12
performs high-frequency vibration as shown in Figure 2c and emits ultrasonic waves into the liquid.

In the basic circuit of the conventional ultrasonic atomizer described above, when the AC power supply voltage shown in FIG. Since the oscillation circuit uses the voltage appearing at the output terminal 4 as the power supply voltage, the amount of atomization of the ultrasonic atomization device changes.

FIG. 3 shows changes in the atomization amount of the ultrasonic atomization device when the AC power supply voltage applied to the terminals 1a and 1b is varied within a range of ±10% around the rated value of 48 Vrms. It can be seen from the figure that as the AC power supply voltage fluctuates, the amount of atomization also changes greatly.

The present invention eliminates the above-mentioned conventional drawbacks and provides an ultrasonic atomization device in which the amount of atomization remains constant even if the AC power supply voltage fluctuates. To explain this invention based on the drawings, in FIG. 4, a portion 15 surrounded by a broken line is an atomization amount stabilizing circuit, and the portions other than this atomization amount stabilizing circuit are shown in FIG. The basic circuit is the same as that of conventional ultrasonic atomizers, so
The same numbers as in FIG. 1 are given. In the atomization amount stabilizing circuit 15, 16 is a diode, 17 is a smoothing capacitor, 18 is a Zener diode whose terminal voltage is constant regardless of the magnitude of the current, and 1
9 and 20 are resistors, and 21 is a transistor. The anode of the diode 16 is connected to the output terminal 4, and the cathode is grounded via the smoothing capacitor 17 and also connected to the Zener diode 18. The diode 16 and the smoothing capacitor 17 constitute a smoothing circuit that converts the voltage appearing at the output terminal 4 into a DC voltage. diode 1
A resistor 19 is connected in series to the Zener diode 18 to which the resistor 6 is connected, and the other end of the resistor 19 is grounded. The base of the transistor 21 is connected to the Zener diode 18 and the resistor 1 via the resistor 20.
9, its emitter is grounded, and its collector is connected to a resistor 6.

That is, the atomization amount stabilizing circuit 15 is connected to the output terminal 4.
The power supply voltage of the oscillation circuit appearing in the diode 16
This DC voltage is converted into a DC voltage by a smoothing capacitor 17, divided by a Zener diode 18 and a resistor 19, and the divided voltage is applied to the base of a transistor 21 through a resistor 20.

Now, when the AC power supply voltage applied to the terminals 1a and 1b increases, the voltage at the output terminal 4 of the rectifier circuit increases. Therefore, the base bias voltage of the oscillation transistor 7 increases.

On the other hand, since the voltage between both terminals of the Zener diode 18 is constant, the base voltage of the transistor 21 increases by an amount commensurate with the increase in the voltage at the output terminal 4. Therefore, the resistance value between the collector and emitter of the transistor 21 becomes small, and the base bias voltage of the oscillation transistor 7 becomes low.

In this way, the rise and fall of the base voltage of the oscillation transistor 7 cancel each other out, and the base voltage is kept constant.

Conversely, when the AC power supply voltage applied to the terminals 1a and 1b decreases, the voltage at the output terminal 4 decreases and the base voltage of the oscillation transistor 7 decreases. On the other hand, the base voltage of the transistor 21 decreases, and the resistance between the collector and emitter of the transistor 21 increases, so that the base bias voltage of the oscillation transistor 7 increases. In this way, the drop and rise in the base voltage of the oscillation transistor 7 cancel each other out, and the base voltage is kept constant.

As described above, the base bias voltage of the oscillating transistor 7 is kept constant regardless of fluctuations in the AC power supply voltage, so the amount of atomization is constant.

Next, another embodiment shown in FIG. 5 will be described. In this figure, the Zener diode 18 in FIG. 4 is removed and a heat-sensitive resistance element 22 is provided in its place.
Same as figure. In this embodiment, the heat-sensitive resistance element 22 is a thermistor whose resistance value has a negative temperature coefficient.

Now, when the AC power supply voltage applied to the terminals 1a and 1b increases, the current flowing through the heat-sensitive resistance element 22 increases, the amount of self-heating increases, and its resistance value decreases. Therefore, the bias voltage of the transistor 21 increases, the resistance between the collector and emitter of the transistor 21 decreases, and the bias voltage of the oscillation transistor 7 decreases. In this way, the increase in the base voltage of the oscillating transistor 7 due to the increase in the AC power supply voltage is canceled out.

Conversely, when the AC power supply voltage applied to the terminals 1a and 1b decreases, the current flowing through the heat-sensitive resistance element 22 decreases, so the amount of self-heating decreases and the resistance value increases. Therefore, the bias voltage of the transistor 21 decreases, the resistance between the collector and emitter of the transistor 21 increases, and the bias voltage of the oscillation transistor 7 increases. In this way, the drop in the base voltage of the oscillating transistor 7 due to the drop in the AC power supply voltage is canceled out.

Furthermore, in the embodiment shown in FIG. 4, if the heat-sensitive resistance element 22 is to be changed to one whose resistance value has a positive temperature coefficient, the positions of the heat-sensitive resistance element 22 and the resistor 19 may be swapped in terms of the circuit configuration.

As explained above, the ultrasonic atomization device of the present invention can be realized by simply adding an atomization amount stabilizing circuit with a simple configuration to the basic circuit of a conventional ultrasonic atomization device. Even if the magnitude of the power supply voltage changes, the amount of atomization can be kept constant.

[Brief explanation of the drawing]

Figure 1 is a basic circuit diagram of a conventional ultrasonic atomizer.
Figures 2a, b, and c are voltage waveform diagrams at various points in the circuit in Figure 1, Figure 3 is a relationship diagram between the AC power supply voltage and the amount of atomization in the ultrasonic atomizer, and Figure 4 is the invention of the present invention. A circuit diagram of an ultrasonic atomization device in an embodiment of
FIG. 5 is a circuit diagram of an ultrasonic atomizer according to another embodiment of the present invention. 1a, 1b...Single-phase AC power input terminal, 2a,
2b, 2c, 2d... Diode, 4... Output terminal of rectifier circuit, 5, 6... Voltage dividing resistor, 7... Oscillation transistor, 16... Diode, 17...
Smoothing capacitor, 18... Zener diode, 19... Resistor, 21... Transistor, 22
...Heat-sensitive resistance element.

Claims (1)

[Scope of utility model registration request] comprising a rectifier circuit that rectifies single-phase alternating current, and an oscillation circuit that uses the output voltage of the rectifier circuit as a power supply voltage,
A transistor whose collector emitter is connected in series with a voltage dividing resistor that supplies a bias voltage to the base of the oscillation transistor of the oscillation circuit, a smoothing circuit that converts the output voltage of the rectifier circuit into a DC voltage, and a smoothing circuit that converts the output voltage of the rectifier circuit into a DC voltage. An ultrasonic atomizer comprising an atomization amount stabilizing circuit comprising a Zener diode that divides the voltage and supplies the voltage to the base of the transistor, or a bias circuit comprising a heat-sensitive resistance element whose resistance value changes depending on temperature and a resistor.