JP2012011320A - Atomizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an atomizer capable of detecting a water leakage, which requires no electrode for water leakage detection and is not affected by sticking of bubbles and the temperature change.SOLUTION: A driving circuit 101 or a resistance value detection circuit 102 is connected between the exciting electrode E of a vibrator 32 and a vibration plate 31 via a switching circuit 103. Normally the switching circuit 103 selects the diving circuit 101 to apply the driving voltage of the driving circuit 101 to the vibrator 32 and in timing performing the water leakage detection, selects the resistance value detection circuit 102. In this state, the resistance value detection circuit 102 generates a voltage signal corresponding to the insulation resistance value between the exciting electrode E of the vibrator 32 and the vibration plate 31.

Description

  The present invention relates to a spraying device that atomizes and sprays a liquid such as water.

  In an atomizer installed in a spraying device equipped with an ultrasonic vibrator, an electrode for water leakage detection is formed inside the holder case so that the excitation of the drive circuit is stopped immediately when water leakage occurs. At the same time, Patent Document 1 discloses an ultrasonic atomizing unit that displays water leakage with a lamp or the like.

  FIG. 1 is a cross-sectional view of an atomizer portion of a spray device disclosed in Patent Document 1. In this atomizer, electrodes 11 and 12 are formed on the bottom surface of the holder case 4, and the piezoelectric element 1 is inserted into a groove provided in the rubber packing 3 and fixed to the fixing metal base 2. If the attachment is incomplete and water enters the holder case from the rubber packing 3 and water accumulates in the electrodes 11 and 12, the operation of the excitation circuit connecting the pair of electrodes 11 and 12 on the bottom surface of the holder case is stopped. An excitation circuit is configured.

  Further, in Patent Document 2, in a steam generator used in a liquid metal cooled fast reactor, in a water leak detection device that detects water leak into a liquid metal due to a heat transfer tube breakage, Alternatively, when hydrogen bubbles generated by the outflow of vapor adhere to the waveguide, the resonance state of the waveguide formed at the tip of the piezoelectric element changes, so that water leakage can be detected with a quick response time. It is supposed to be possible.

Japanese Utility Model Publication No. 6-72665 JP 2000-249784 A

  Patented to an atomizer that generates mist on the second surface opposite to the first surface of the diaphragm in contact with the liquid by vibrating the vibration plate in which the atomizing holes are formed with a vibrator. An example in which the structures of Documents 1 and 2 are applied is shown in FIG. 2A is a perspective view of the atomizer, and FIG. 2B is an exploded perspective view thereof. This atomizer is provided at the tip of the liquid transport path. The atomizer includes a pedestal 43, an atomizer holder 47, a lower packing 49, an upper packing 50, and a cover member 51. A diaphragm including a piezoelectric element is sandwiched between the lower packing 49 and the upper packing 50.

  The leakage detection electrodes 53S and 54S are arranged on the pedestal 43, and the leakage detection terminals 53T and 54T are drawn to the outside. A lead wire 52 of a piezoelectric element that vibrates the diaphragm is drawn out.

  Thus, when the structure for water leak detection shown in Patent Document 1 is applied to an atomizer, it is necessary to provide a dedicated electrode for water leak detection, leading to an increase in cost. In addition, since the water leakage detection electrodes 53S and 54S are arranged at positions away from the diaphragm, the water leakage cannot be detected unless water leaks between the lower packing 49 and the upper packing 50 or overflows from the cover member 51. .

  In the case of Patent Document 2, when water adheres to the waveguide, the frequency characteristic of the impedance of the piezoelectric element changes depending on the amount of adhesion. Therefore, since the oscillation frequency changes according to the presence or absence of water leakage, the presence or absence of water leakage can be detected based on the measured oscillation frequency.

  However, it is known that when the diaphragm is vibrated in contact with the liquid, cavitation occurs at the same time as atomization, and bubbles are generated in the liquid. Changes. Further, the resonance frequency of the piezoelectric element also changes due to temperature changes. For this reason, when it is going to detect a water leak based on the change of the resonant frequency of a piezoelectric element, there exists a possibility of misdetecting.

  An object of the present invention is to provide a spray device that does not require an electrode for water leakage detection and can detect water leakage without being affected by the adhesion of bubbles or temperature changes.

The spray device of the present invention includes a vibration plate, a vibrator that vibrates the vibration plate, and a liquid transporting means for transporting a liquid to the vibration plate, the first surface of the vibration plate being in contact with the liquid, In the spraying device for generating a mist from the second surface opposite to the first surface by applying vibration to the liquid,
The vibrator is a piezoelectric element including an excitation electrode, and a resistance value (or a resistance value) between a driving voltage generation circuit that generates a driving voltage to be applied to the excitation electrode of the piezoelectric element and the excitation electrode of the piezoelectric element. A resistance value detection circuit that detects a corresponding electric variable), and a circuit that switches between a state in which the drive voltage generation circuit is connected to the excitation electrode and a state in which the resistance value detection circuit is connected to the excitation electrode. Switching means.

  For example, the diaphragm is a metal plate, the vibrator is a piezoelectric element attached to the diaphragm, and one of the excitation electrodes is the diaphragm.

  In addition, liquid transport control means for stopping transport of the liquid by the liquid transport means based on the detection result of the resistance value detection circuit is provided.

  According to the present invention, an electrode for detecting water leakage is unnecessary, and water leakage can be detected without being affected by the adhesion of bubbles or temperature changes.

FIG. 1 is a cross-sectional view of an atomizer portion of a spray device disclosed in Patent Document 1. FIG. 2 shows a mist that generates a mist on the second surface opposite to the first surface of the diaphragm in contact with the liquid by vibrating the diaphragm in which the atomization holes are formed by a vibrator. It is a figure which shows the example which applied the structure of patent document 1, 2 to the generator. FIG. 3 is a cross-sectional view of the spray device 100 according to the first embodiment. FIG. 4 is a partially broken perspective view showing the structure of the atomizer portion shown in FIG. FIG. 5 is a cross-sectional view of the diaphragm 31. FIG. 6 is a plan view of the diaphragm 31. FIG. 7 is a block diagram of a circuit connected to the vibrator. FIG. 8 is a circuit diagram of the drive circuit 101, the resistance value detection circuit 102, and the switching circuit 103. FIG. 9 is a diagram showing the relationship between the insulation resistance value between the excitation electrodes of the piezoelectric element Y1 (insulation resistance value between the excitation electrode E of the vibrator 32 and the diaphragm 31) and the mass of water adhering. FIG. 10 is a diagram showing the relationship between the output voltage of the resistance value detection circuit 102 and the insulation resistance IR.

<< First Embodiment >>
FIG. 3 is a cross-sectional view of the spray device 100 according to the first embodiment. The spray device 100 includes an atomizer 30, a liquid reservoir 22, a liquid transport path 23 that transports liquid from the liquid reservoir 22 to the atomizer 30, and a blower 21. The blower 21 applies a pressure to the liquid level of the liquid W in the liquid storage unit 22, thereby transporting the liquid from the liquid storage unit 22 toward the atomizer 30 through the liquid transport path 23 using the water head difference. . The atomizer 30 is provided with a diaphragm 31 in which a large number of atomization holes are formed.

In this example, the liquid W stored in the liquid storage unit 22 is electrolyzed water containing active oxygen having a sterilizing / deodorizing effect. Specifically, an electrode for electrolysis is provided in the liquid storage unit 22, and electrolysis of tap water uses chloride ions (Cl-) contained in tap water to generate “hypochlorous acid”. (HCIO) ”and“ OH radicals ”are generated. By spraying this electrolyzed water indoors, the indoor air is sterilized and deodorized.
FIG. 4 is a partially broken perspective view showing the structure of the atomizer portion shown in FIG. The atomizer 30 is provided at the tip of the liquid transport path 23. A pedestal 33 for installing the atomizer 30 is formed at the tip of the liquid transport path 23. The atomizer 30 is installed on the pedestal 33 while being held by the atomizer holder 37.

  The atomizer 30 includes a diaphragm 31, a vibrator 32, a lower packing 39, an upper packing 40, and a cover member 41. The vibration plate 31 is a disk-shaped metal plate, and a large number of atomization holes having a diameter of 0.08 mm or less are formed at the center of the metal plate. The vibrator 32 is a ring-shaped piezoelectric element and is affixed to the diaphragm 31 at a concentric position. The periphery of the diaphragm 31 is sandwiched between the lower packing 39 and the upper packing 40.

  FIG. 5 is a cross-sectional view of the diaphragm 31. An excitation electrode is formed on the upper surface of the vibrator 32 which is the piezoelectric element, and the vibrator 32 expands and vibrates when an AC voltage is applied between the excitation electrode and the diaphragm 31. By attaching the vibrator 32 to the diaphragm 31, the diaphragm 31 bends and vibrates.

The space formed below the diaphragm 31 by the pedestal 33, the atomizer holder 37, and the lower packing 39 is filled with electrolyzed water transported through the liquid transport path 23. When the vibrator 32 vibrates at 160 kHz, for example, by the drive circuit, water is discharged as mist from the numerous atomization holes provided in the diaphragm 31.
FIG. 6 is a plan view of the diaphragm 31. A thin portion 31C is formed at the center of the diaphragm 31, and a number of atomization holes MH are formed in the thin portion 31C. The minute electrolyzed water filled in these atomization holes MH is atomized by the vibration of the vibration plate 31, separated from the vibration plate 31, and discharged (floated) to the upper surface of the vibration plate 31.

  Further, an air discharge hole 35 is formed in the pedestal portion 33 separately from the liquid transport path 23, and a waterproof ventilation sheet 36 is formed at the entrance of the air discharge hole 35. If the diaphragm 31 is vibrated in the state where the space below the diaphragm 31 is filled with electrolyzed water, bubbles may be generated due to a cavitation phenomenon. If the bubbles block the atomization hole of the diaphragm 31, the atomization may be hindered. Therefore, by forming the air discharge hole 35 whose entrance is covered with the waterproof ventilation sheet 36, the bubbles can be efficiently discharged without leaking the electrolyzed water to the outside.

FIG. 7 is a block diagram of a circuit connected to the vibrator.
A drive circuit 101 and a resistance value detection circuit 102 are connected between the excitation electrode E of the vibrator 32 and the diaphragm 31 via the switching circuit 103. Normally, the switching circuit 103 selects the drive circuit 101, applies the drive voltage of the drive circuit 101 to the vibrator 32, and selects the resistance value detection circuit 102 at the timing of detecting water leakage. In this state, the resistance value detection circuit 102 generates a voltage signal corresponding to the insulation resistance value between the excitation electrode E of the vibrator 32 and the diaphragm 31.

  FIG. 8 is a circuit diagram of the drive circuit 101, the resistance value detection circuit 102, and the switching circuit 103. In the drive circuit 101, the transistors Q1 and Q2 and the resistor R10 constitute a buffer circuit, and this buffer circuit is connected to the output terminal of the operational amplifier U1A. A piezoelectric element Y1 is connected between the non-inverting input terminal of the operational amplifier U1A and the output terminal of the buffer circuit via optical MOS FETs RY2 and RY3 which are relays of the switching circuit 103. A parallel circuit of a capacitor C3 and a resistor R9 is connected between the inverting input terminal of the operational amplifier U1A and the output terminal of the buffer circuit. The non-inverting input terminal and the inverting input terminal of the operational amplifier U1A are grounded to the reference potential via resistors R1 and R2.

  The fifth and sixth terminals of the optical MOS FETs RY2 and RY3 of the switching circuit 103 are normally off, and the seventh and eighth terminals are normally on. The second and fourth terminals of the optical MOS FETs RY2 and RY3 are grounded. When a selection voltage (positive voltage) is applied to the first and third terminals, the fifth and sixth terminals become conductive, and the seventh and eighth terminals. Between terminals is opened. Therefore, in a normal state where the Select terminal is at the ground potential, the piezoelectric element Y1 is connected to the drive circuit 101 and oscillates. In the resistance detection state in which the Select terminal is at a high level, the piezoelectric element Y1 is connected to the resistance value detection circuit 102. At this time, the reference voltage V 6 is applied to the first end of the piezoelectric element, and the voltage at the second end is input to the resistance value detection circuit 102.

  A resistor R19 is connected between the output terminal and the inverting input terminal of the operational amplifier U2D of the resistance value detection circuit 102. A resistor R18 is connected between the input portion of the resistance value detection circuit 102 and the inverting input terminal of the operational amplifier U2D. With this configuration, the resistance value detection circuit 102 and the piezoelectric element Y1 function as an inverting amplifier circuit.

  If there is no water leakage, the input voltage of the resistance value detection circuit 102 is 0 V in the resistance detection state, so the output voltage of the IR OUT terminal is 0 V. If there is water leakage, the insulation resistance value between the excitation electrodes of the piezoelectric element Y1 decreases, and a certain positive voltage is input to the resistance value detection circuit 102 in the resistance detection state. Therefore, the output voltage of the IR OUT terminal is It becomes a certain negative potential.

  An output port of a microcomputer is connected to the Select terminal, and the drive mode and the resistance detection mode are alternately switched at predetermined intervals under the control of the microcomputer. Further, the IR OUT terminal of the resistance value detection circuit 102 is connected to the input port of the microcomputer, and the voltage of the IR OUT terminal is read by the microcomputer.

  FIG. 9 is a diagram showing the relationship between the insulation resistance value between the excitation electrodes of the piezoelectric element Y1 (insulation resistance value between the excitation electrode E of the vibrator 32 and the diaphragm 31) and the mass of water adhering. FIG. 10 is a diagram showing the relationship between the output voltage of the resistance value detection circuit 102 and the insulation resistance IR.

  Here, a state in which the mass of attached water exceeds 0.1 g is regarded as a water leakage state. The resistance value when the mass of adhering water is 0.1 g is about 1 MΩ as shown in FIG. When the insulation resistance value is 1 MΩ, the output voltage of the resistance value detection circuit 102 reaches −9 V as shown in FIG. Therefore, for example, −5V is set as the threshold value, and when the output voltage of the resistance value detection circuit 102 falls below −5V, it is regarded as a water leakage state. If it is regarded as a water leakage state, an indicator representing the water leakage state is displayed and the blower 21 is stopped to prevent further water leakage. When the diaphragm is driven in a state where the transportation of water by the blower 21 is stopped, excess water that has oozed out on the upper surface of the diaphragm is gradually atomized to eliminate the water leakage. When the water leakage state is eliminated, the blower 21 is driven again to return to the normal operation.

  The relay provided in the switching circuit may use a mechanical relay in addition to the semiconductor relay.

E ... Excitation electrode IR ... Insulation resistance MH ... Atomization hole Q1, Q2 ... Transistor U1 ... Operational amplifier U1A ... Operational amplifier U2 ... Operational amplifier U2D ... Operational amplifier U3 ... Operational amplifier W ... Liquid Y1 ... Piezoelectric element 21 ... Blower 22 ... Liquid reservoir 23 ... Liquid transport path 30 ... Atomizer 31 ... Vibration plate 31C ... Thin portion 32 ... Vibrator 33 ... Pedestal portion 37 ... Atomizer holder 39 ... Lower packing 40 ... Upper packing 41 ... Cover member 43 ... Pedestal portion 47 ... Atomization Holder 49 ... Lower packing 50 ... Upper packing 51 ... Cover member 52 ... Lead wires 53S, 54S ... Water leakage detection electrodes 53T, 54T ... Water leakage detection terminal 100 ... Spraying device 101 ... Drive circuit 102 ... Resistance value detection circuit 103 ... Switching circuit

Claims (3)

A vibration plate, a vibrator that vibrates the vibration plate, and a liquid transport unit that transports liquid to the vibration plate, the first surface of the vibration plate is in contact with the liquid, and the liquid is vibrated, In the spraying device for generating mist from the second surface opposite to the first surface,
The vibrator is a piezoelectric element provided with an excitation electrode,
A drive voltage generation circuit for generating a drive voltage to be applied to the excitation electrode of the piezoelectric element;
A resistance value detection circuit for detecting a resistance value between excitation electrodes of the piezoelectric element;
Circuit switching means for switching between a state in which the drive voltage generation circuit is connected to the excitation electrode and a state in which the resistance detection circuit is connected to the excitation electrode;
A spraying device comprising:   The spraying device according to claim 1, wherein the diaphragm is a metal plate, the vibrator is a piezoelectric element attached to the diaphragm, and one of the excitation electrodes is the diaphragm.   The spray apparatus according to claim 1, further comprising a liquid transport control unit that stops transport of the liquid by the liquid transport unit based on a detection result of the resistance value detection circuit.

Images