JPH0585463U - Ultrasonic atomizer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an ultrasonic atomizer capable of reliably driving a vibrator at a fundamental resonance frequency. [Structure] A drive circuit 2 for driving a vibrator 1, that is, an oscillator 9, a drive switch 10, an amplifier circuit 11, and a voltage detector 1.
2. In the PLL circuit including the current detector 13, the phase comparison circuit 14, and the limiter circuit 15, by temporarily increasing the amplification factor of the amplification circuit 11 at least once,
Even when the vibrator 1 is driven at a resonance point (sub-resonance point) other than the fundamental resonance frequency, the reaction at the sub-resonance point is promptly released by the reaction due to the change in the amplification factor, and the drive at the fundamental resonance frequency is performed. Definitely achieved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ultrasonic atomizer used in a hand disinfection device, etc., and particularly to an ultrasonic atomizer in which a high frequency signal supplied to a vibrator is controlled by a PLL (phase lock loop) circuit. It relates to an atomizing device.

[0002]

[Prior Art]

 Conventionally, for example, an ultrasonic atomizer proposed by the applicant of the present application, which is described in Japanese Patent Application No. 3-71825, expands the amplitude of the vibration of the vibrator to a vibrator that generates vibration by applying a high frequency signal. The horns are connected so that the liquid supplied to the horn is atomized by the vibration output from the horn.

On the other hand, the vibrator has the highest vibration generation efficiency when driven at its basic resonance frequency, but the vibration generation efficiency is significantly reduced when the frequency of the drive signal deviates even slightly from the basic resonance frequency. Therefore, as a method of always bringing the frequency of the drive signal close to the fundamental resonance frequency, for example, a PLL control method as described in Japanese Patent Application No. 3-221652 is adopted. In this control method, the oscillator is driven by a voltage-controlled oscillator whose oscillation frequency is determined in proportion to the control voltage input from the outside, and at the same time the drive voltage and drive current are detected to synchronize the phases of both. It is intended to track the fundamental resonance frequency by feedback controlling the control voltage of the oscillator.

[0004]

[Problems to be solved by the device]

 By the way, a horn is attached to the oscillator to expand the amplitude of the vibration generated by the oscillator, but by installing the horn, many sub-resonance points occur near the basic resonance frequency, Although rare, the oscillator may be driven at this sub-resonance point. In this case, the oscillator cannot enter the normal resonance state, so if liquid is supplied to the horn in this state, the horn cannot atomize the liquid and causes liquid dripping, which is normal. There was a problem that it was impossible to drive.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic atomizer capable of reliably driving a vibrator at a fundamental resonance frequency. is there.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a vibrator that generates vibration by applying a high-frequency signal, a horn that expands and outputs the amplitude of the vibration generated by the vibrator, and a liquid to the horn. A liquid supply means for supplying the liquid crystal, and a vibrator drive circuit including a control circuit and an amplifier circuit for detecting the voltage waveform and the current waveform supplied to the vibrator and comparing the phases of the two to control the drive frequency. In an ultrasonic atomizer that atomizes the liquid supplied to the horn by the output vibration of the horn, the vibrator is operated prior to the operation of the liquid supply means, and the amplification is performed in this state. A control means for temporarily changing the amplification factor of the circuit at least once is provided.

[0007]

[Action]

 According to the ultrasonic atomizing device of the present invention, the vibrator vibrates when the driving signal is applied to the vibrator from the vibrator driving circuit. At this time, the voltage and current of the drive signal are detected and controlled so that the phases of both are synchronized, so that the oscillator is driven at its basic resonance frequency. At that time, the oscillator operates prior to the operation of the liquid supply means, and the amplification factor of the amplifier circuit temporarily changes at least once in this state. Even when driven, the reaction at the resonance point is quickly released by the reaction due to the change in the amplification factor, and the drive at the fundamental resonance frequency is achieved.

[0008]

【Example】

 1 to 10 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a Langevin type vibrator that generates vibration by applying a high-frequency signal. For example, this vibrator 1 is used to cause the vibrator 1 to generate a constant vibration. The drive circuit 2 is connected. The drive circuit 2 is driven by electric power supplied from a power source 3 such as a household AC power source.

Reference numeral 4 denotes a horn that expands the amplitude of the vibration generated in the vibrator 1 and outputs it from the lower end thereof, and the upper end thereof is connected to the vibrator 1. The upper end of the horn 4 is formed to have the same diameter as that of the vibrator 1. The lower part of the horn 4 has a smaller diameter than the upper end, and the lower part of the small diameter part has a slightly larger diameter than the upper part. Has a small diameter up to the lower end. Further, as shown in FIG. 2, at the boundary portion between the upper end portion of the horn 4 and the small diameter portion below the horn 4, an annular groove 4a formed in the circumferential direction of the horn 4 and an annular groove 4a are formed. Each of the flange portions 4b formed below is provided. On the other hand, the lower end of the horn 4 is formed into a substantially conical shape, and forms the vibration output portion 4c of the horn 4. The vibration output portion 4c is composed of two conical surfaces having different apex angles, and the conical surface on the tip side is formed to have a larger apex angle than the other conical surface. The apex angle of each conical surface may be set arbitrarily according to the desired spraying form, but if it is used for finger spraying, the conical surface on the tip side should be about 60 ° to 120 ° above the conical surface. It is suitable to set the surface at about 10 ° to 80 °.

A pump 5 supplies liquid to the horn 4, and its discharge side is connected to a nozzle 5a facing the side surface of the horn 4, and its suction side is connected to a liquid storage tank 5b.

Reference numeral 6 denotes a liquid reservoir holder for storing the disinfectant liquid on the outer periphery of the horn 4, and as shown in FIG. 2, a horn accommodating portion 6 a that covers the horn 4 below the upper end portion, and a horn. It comprises a mounting portion 6b extending horizontally from both upper ends of the housing portion 6a, and the mounting portion 6b is used for fixing to a mating component. The horn accommodating portion 6a is formed in a substantially cylindrical shape, and the bottom surface of the horn accommodating portion 6a forms an inclined surface that becomes lower toward the center, and the lower end side of the horn 4 penetrates through the center portion of the bottom surface. This through-hole supports the outer periphery of the horn 4 by its opening edge, and at two points of the opening edge, liquid outlets 6c are formed which are cut out in a concave shape as shown in FIGS. 3 and 4. There is. Further, projections 6d corresponding to the respective outlets 6c are provided in the lower part of the horn accommodating portion 6a, and the projections 6d extend downward along the side surface of the horn 4 and the respective projections 6d. A slight gap is formed between the horn and the side surface of the horn 4. Further, the nozzle 5a of the pump 5 is inserted into the side surface of the horn accommodating portion 6a, and a ventilation hole 6e is provided above the nozzle 5a to keep the inside and outside of the horn accommodating portion 6a at the same air pressure. Further, a step portion 6f corresponding to the flange portion 4b of the horn 4 is formed at the upper end edge of the horn accommodating portion 6a, and the lower surface side of the flange portion 4b is fitted into the step portion 6f. On the other hand, screw mounting portions 6g are provided at two positions of the mounting portion 6b near the horn accommodating portion 6a, and a screw 7 is screwed from above to each screw mounting portion 6g. A washer 8 is attached to each screw 7, and one end of each washer 8 is inserted into the annular groove 4a of the horn 4. As a result, the flange portion 4b is held with a play between one end of each washer 8 and the step portion 6f.

As shown in FIG. 5, the drive circuit 2 includes a voltage control oscillator 9 (hereinafter, referred to as an oscillator 9) that supplies a drive signal to the vibrator 1, and a drive switch 10 that opens and closes the drive circuit 2. An amplifier circuit 11 that amplifies the drive signal from the oscillator 9, a voltage detector 12 and a current detector 13 that respectively detect the voltage and current of the drive signal supplied from the amplifier circuit 11 to the vibrator 1, and a voltage detector 12 And a phase comparison circuit 14 for comparing the phases of the voltage and current detected by the current detector 13, and a limiter circuit 15 for regulating the control voltage of the oscillator 9, and the well-known PLL (phase lock loop). B) It constitutes a circuit. The oscillator 9 is driven by the voltage supplied from the power supply 3 and also generates an oscillation frequency proportional to the control voltage input from the phase comparison circuit 14. Further, the phase comparison circuit 14 outputs the control voltage (DC voltage) of the oscillator 9 based on the comparison result of the detected voltage and the phase of the current, and if the phase of the current leads the voltage, the control voltage becomes high. In the opposite case, the control voltage is lowered. On the other hand, in the limiter circuit 15, the control voltage of the oscillator 9 is controlled so that the oscillation frequency of the oscillator 9 falls within a predetermined range centered on the fundamental resonance frequency of the oscillator 1. If the oscillation frequency is within this range, One can enter resonance.

As shown in FIG. 6, the amplifier circuit 11 includes an amplifier 11a, first and second setters 11b and 11c each having a predetermined amplification factor set, and a switching switch for switching the amplification factor. 16, one end of each setter 11b, 11c is connected to the common contact 16a of the changeover switch 16 and the contact 16b on the ON side, and the other end of each setter 11b, 11c is connected to both ends of the amplifier 11a. There is. The OFF-side contact 16c of the changeover switch 16 bypasses the second setting device 11c and is connected to one end of the amplifier 11a. That is, when the change-over switch 16 is OFF, the amplifier circuit 11 operates at the amplification factor (normal gain) of only the first setter 11b, and when the change-over switch 16 is turned ON, the first setter 11b is changed to the first setter 11b. It is designed to operate at an amplification factor (full power gain) to which the 2 setting device 11c is added.

Reference numeral 17 denotes a control unit constituted by a microcomputer or the like, which is connected to the drive circuit 2 and the pump 5 as shown in FIG. 1 and has a timer T 1 for setting a time t 1, which will be described later. The amplifier circuit 11 and the pump 12 of the drive circuit 2 are controlled according to the program.

With the above configuration, when the drive switch 10 is turned on, the drive signal output from the oscillator 9 is amplified by the amplifier circuit 11 and applied to the vibrator 1. At this time, the voltage and current of the drive signal are detected by the voltage detector 12 and the current detector 13, and the phases of both are compared by the phase comparison circuit 14. The phase comparison circuit 14 operates so that the control voltage becomes higher if the current phase leads the voltage and becomes lower in the opposite case, so that the frequency of the drive signal approaches the basic resonance frequency. Feedback control is performed. The control voltage output from the phase comparison circuit 14 is controlled by the limiter circuit 15 so that the oscillation frequency of the oscillator 9 falls within the above range.

When a high-frequency signal is applied from the drive circuit 2 to the vibrator 1 in this way, the vibration generated by the vibrator 1 has its amplitude expanded by the horn 4 and is output from the vibration output section 4c at the lower end. It At this time, vibration nodes and antinodes alternately appear in the horn 4 in the axial direction of the horn 4, and the vibration output section 4c corresponds to the antinode having the largest amplitude. Further, when the liquid to be atomized is supplied into the liquid reservoir holder 6 by the pump 5, the liquid temporarily accumulates around the horn 4 and gradually flows out from each outlet 6c. Further, the liquid that has flowed out reaches the vibration output unit 4c, contacts the vibration output unit 4c, and is atomized at the same time. At this time, the liquid flowing out from each outflow port 6c is guided between the protrusion 6d and the horn 4 by the action of the capillary action, and each outflow port 6a is placed on both sides with the horn 4 in between. Since it is located, the liquid is concentratedly supplied to the vibration output portion 4c at the locations corresponding to the respective outlets 6c. Therefore, as shown in FIGS. 7 and 8, the spraying direction of the atomized liquid spreads laterally, and the spraying form A suitable for a finger disinfecting device or the like in which both hands are held and used is formed.

Here, the operation of the control unit 17 will be described with reference to the flowchart of FIG. 9 and the time chart of FIG. First, when the drive switch 10 of the drive circuit 2 is turned on (S1), the variable N is set to an initial value 0 (S2), and then 1 is added to N (S3). Next, the changeover switch 16 of the amplifier circuit 11 is turned on (S4), and the timer T1 is operated (S5). Then, when the time t1 (for example, 300 ms) has elapsed (S6) and N is 3 or less (S7), the changeover switch 16 is turned off (S8) and the timer T2 is activated (S9). Then, when the time t2 (for example, 10 ms) has elapsed (S10), the process returns to step S3, 1 is added to N, and the changeover switch 16 is turned on again (S4). After repeating this operation (steps S3 to S10) three times in total, when it is determined in step S7 that N is larger than 3, the changeover switch 16 is set to OF F (S11) and the pump 5 is operated (S12). ). That is, since the amplification factor of the amplifier circuit 11 is temporarily increased by the operations of steps S3 to S10, even when the resonator 1 is driven at a resonance point (sub-resonance point) other than the fundamental resonance frequency, this The reaction at the sub-resonance point is quickly released by the reaction due to the change in the amplification factor, and the drive at the fundamental resonance frequency is achieved. The number of times the amplification factor is changed is an example, and it goes without saying that it can be set arbitrarily at the time of design.

As described above, according to the ultrasonic atomizing device of this embodiment, the vibrator 1 is operated prior to the operation of the pump 5, and the amplification factor of the amplifier circuit 11 is temporarily increased in this state. As a result, even when the vibrator 1 is driven at a resonance point other than the fundamental resonance frequency, the reaction at the resonance point is quickly released by the reaction due to the change in the amplification factor. Therefore, the vibrator 1 can be reliably driven at the basic resonance frequency, and normal operation can always be performed. Also, the operation of temporarily increasing the amplification factor of the amplifier circuit 11 can be used for power-up at low temperature.

[0020]

[Effect of the device]

 As described above, according to the ultrasonic atomizing device of the present invention, since the vibrator can be reliably driven at the basic resonance frequency, it is possible to always perform normal operation and improve reliability. Lead to

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an ultrasonic atomizer showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional side view showing a state where a liquid reservoir holder is attached to a horn.

FIG. 3 is a partial side sectional view of a liquid reservoir holder.

FIG. 4 is a sectional view taken along the line AA of FIG.

FIG. 5 is a block diagram of a drive circuit

FIG. 6 is a configuration diagram of an amplifier circuit.

FIG. 7 is a side view showing a spraying form of liquid.

8 is a sectional view taken along the line BB of FIG.

FIG. 9 is a flowchart showing the operation of the control unit.

FIG. 10 is a time chart showing the operation of the control unit.

[Explanation of symbols]

1 ... vibrator, 2 ... drive circuit, 4 ... horn, 5 ... pump,
9 ... Oscillator, 11 ... Amplification circuit, 12 ... Voltage detector, 13
... current detector, 14 ... phase comparison circuit, 15 ... limiter circuit, 17 ... control unit.

Claims (1)

[Scope of utility model registration request] 1. A vibrator that generates vibration by applying a high-frequency signal, a horn that expands and outputs the amplitude of the vibration generated by the vibrator, and a liquid supply means that supplies liquid to the horn. And a vibrator drive circuit including a control circuit and an amplifier circuit for detecting a voltage waveform and a current waveform supplied to the vibrator, comparing the phases of the both, and controlling the drive frequency,
In an ultrasonic atomization device for atomizing the liquid supplied to the horn by the output vibration of the horn, the vibrator is operated prior to the operation of the liquid supply means,
An ultrasonic atomization device, characterized in that a control means for temporarily changing the amplification factor of the amplification circuit at least once in this state is provided.