Ultrasonic atomization device and ultrasonic atomization method

Abstract

To provide an ultrasonic atomizer capable of preventing the empty burning of an ultrasonic vibrator without being accompanied by the complication or enlargement of the whole apparatus.SOLUTION: The ultrasonic atomizer 10 includes an atomization chamber 11 for containing liquid W1 to be atomized, an ultrasonic vibrator 20 disposed on a bottom portion 12 of the atomization chamber 11, and a droplet recovery pipe 30. The ultrasonic atomizer 10 atomizes a liquid S1 by supplying high-frequency power to an ultrasonic vibrator 20 to generate an ultrasonic W2 and generating a liquid column W3 at a liquid surface W1 immediately above the ultrasonic vibrator 20. The droplet recovery pipe 30 recovers the droplets W3 scattered from the liquid column W4 to form a liquid flow W5 flowing downward. The droplet recovery pipe 30 discharges the liquid flow W5 in the vicinity of the vibration surface 21 of the ultrasonic vibrator 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic atomization device and an ultrasonic atomization method. [Background technology]

[0002] Ultrasonic atomizers that atomize liquids using ultrasonic vibrations are well known. A typical ultrasonic atomizer includes an atomization tank for containing the liquid to be atomized and an ultrasonic vibrator installed at the bottom of the atomization tank.

[0003] This type of ultrasonic atomization device has a problem in that, when used for a long period of time, air bubbles adhere to the vibration surface of the ultrasonic vibrator, making it prone to dry-burning. To address this problem, ultrasonic atomization devices equipped with a means for removing air bubbles from the vibration surface have been proposed (see, for example, Patent Document 1). The device in Patent Document 1 includes a liquid supply and cleaning unit located near the ultrasonic vibrator, and a pressurized liquid supply device connected to the liquid supply and cleaning unit via a connecting pipe and supplying pressurized liquid. The pressurized liquid supply device is driven to pump and deliver the pressurized liquid, which is then ejected from the ejection port of the liquid supply and cleaning unit, thereby removing air bubbles from the vibration surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-264705 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the above-mentioned conventional technology, it is necessary to provide a separate pressurized liquid supply device outside the atomization tank for pressure-feeding the pressurized liquid to the liquid supply and cleaning section, and it is also necessary to supply driving force (electricity, etc.) to operate the pressurized liquid supply device, which not only tends to make the entire device more complicated and larger, but also leads to problems such as high costs.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide an ultrasonic atomization device and an ultrasonic atomization method that can prevent the ultrasonic vibrator from running dry without increasing the complexity or size of the entire device. [Means for solving the problem]

[0007] In order to solve the above problem, the invention described in claim 1 is an ultrasonic atomization device comprising an atomization tank for containing a liquid to be atomized, and an ultrasonic vibrator installed at the bottom of the atomization tank, which generates ultrasonic waves by supplying high-frequency power to the ultrasonic vibrator and generates a liquid column on the liquid surface directly above the ultrasonic vibrator, thereby atomizing the liquid, and characterized in that the ultrasonic atomization device is characterized in that the atomization tank is provided with a droplet recovery pipe that recovers droplets scattered from the liquid column to form a downward liquid flow and releases the liquid flow near the vibration surface of the ultrasonic vibrator.

[0008] Therefore, according to the invention described in claim 1, a liquid flow formed by droplets scattered from the liquid column is released from the droplet recovery tube near the vibration surface of the ultrasonic vibrator, thereby removing air bubbles from the vibration surface. As a result, oscillation occurs with the liquid in reliable contact with the vibration surface, preventing the ultrasonic vibrator from running dry and thus preventing breakdown of the ultrasonic vibrator. Furthermore, in claim 1, the provision of the droplet recovery tube eliminates the need for a means for pumping pressurized liquid near the vibration surface, preventing the entire device from becoming more complex and larger, and suppressing cost increases.

[0009] The invention described in claim 2 is based on claim 1, and its gist is that the droplet recovery tube has a lower end opening that is positioned lower than the liquid level, an upper end opening that is positioned higher than the liquid level and has an enlarged shape with a larger cross-sectional area than the lower end opening, and a tube body that connects the lower end opening and the upper end opening.

[0010] Therefore, according to the invention described in claim 2, by positioning the lower end opening of the droplet recovery tube at a position lower than the liquid level, the lower end opening and the vibration surface of the ultrasonic vibrator can be brought closer together. This allows the liquid flow emitted from the lower end opening to reliably collide with the vibration surface of the ultrasonic vibrator. Furthermore, since the upper end opening of the droplet recovery tube is positioned at a position higher than the liquid level and has an expanded diameter with a larger cross-sectional area than the lower end opening, droplets scattered from the liquid column can be efficiently recovered.

[0011] The invention described in claim 3 is based on claim 2, and is characterized in that the upper end opening is arranged so as not to entirely surround a liquid column generation region, which is the region above the liquid surface where the liquid column is generated, and is offset laterally to avoid the liquid column generation region.

[0012] Therefore, in the invention described in claim 3, the upper end opening does not need to be designed to surround the periphery of the liquid column generation region, making it easier to manufacture the droplet recovery tube. Furthermore, the components that make up the droplet recovery tube are smaller, reducing the manufacturing cost of the droplet recovery tube. Furthermore, because the upper end opening is positioned offset laterally to avoid the liquid column generation region, the risk of the upper end opening interfering with the generation of the liquid column is avoided.

[0013] The invention described in claim 4 is characterized in that, in claim 3, the upper end opening is a funnel-shaped liquid reservoir portion whose cross-sectional area gradually increases from the bottom to the top.

[0014] Therefore, in the invention described in claim 4, because the inner surface of the liquid reservoir is inclined, droplets that scatter from the liquid column and adhere to the inner surface of the liquid reservoir flow downward along the inner surface of the liquid reservoir due to the action of gravity, passing from the lower end of the liquid reservoir through the tube body and the lower end opening in that order, before falling onto the vibration surface of the ultrasonic vibrator. Therefore, there is no need for a means to pressure-feed the droplets to the vibration surface, which prevents the entire device from becoming too complicated and large.

[0015] The invention described in claim 5 is characterized in that, in claim 2, the lower end opening is integrally formed at the lower end of the tube body and is positioned close to the vibration surface while avoiding a position directly above the center of the ultrasonic vibrator.

[0016] Therefore, according to the invention described in claim 5, since the lower end opening is formed integrally with the pipe body, the number of parts in the droplet recovery pipe can be reduced compared to, for example, a pipe formed separately from the pipe body, thereby reducing the cost of the device. Furthermore, since the lower end opening is positioned so as not to be directly above the center of the ultrasonic vibrator, the risk of the lower end opening interfering with the generation of the liquid column can be avoided.

[0017] The invention described in claim 6 is characterized in that in claim 5, the lower end opening is arranged facing obliquely downward so as to face the center of the ultrasonic vibrator.

[0018] Therefore, according to the invention described in claim 6, the lower end opening of the droplet recovery tube can be brought close to the center of the ultrasonic vibrator, so that the liquid flow released from the lower end opening can be reliably collided with the vibration surface of the ultrasonic vibrator.

[0019] The invention described in claim 7 is characterized in that, in claim 6, the pipe body is a tube whose lower end is bent diagonally downward, and the lower end opening is integrally formed at the lower end of the tube.

[0020] Therefore, according to the invention described in claim 7, the tube body is a tube with a lower end bent obliquely downward, so the lower end opening formed at the lower end of the tube can be easily brought close to the center of the ultrasonic vibrator. This allows the liquid flow emitted from the lower end opening to more reliably collide with the vibration surface of the ultrasonic vibrator. Furthermore, because the tube has a curved shape, the upper end opening connected to the upper end of the tube can be positioned laterally offset so as not to be directly above the ultrasonic vibrator. This avoids the risk of the upper end opening interfering with the generation of a liquid column. Furthermore, because the lower end opening is integrally formed with the tube, the number of parts in the droplet collection tube can be reduced compared to, for example, a tube formed separately, thereby reducing device costs.

[0021] The invention described in claim 8 is based on any one of claims 1 to 7 and further comprises a deterrent mechanism that recovers the droplets scattered from the liquid column at a position above the droplet recovery tube and intermittently supplies the liquid, which is a collection of the recovered droplets, to the droplet recovery tube.

[0022] Therefore, according to the invention described in claim 8, the liquid, which is a collection of droplets collected by the deer-scare mechanism, flows in one go and becomes a powerful liquid flow when it is supplied to the droplet collection tube. This allows the powerful liquid flow to be released from the droplet collection tube and collide with the vibration surface of the ultrasonic vibrator. This ensures that air bubbles adhering to the vibration surface can be removed reliably.

[0023] The invention described in claim 9 is an ultrasonic atomization method comprising: an atomization step of supplying high-frequency power to an ultrasonic vibrator placed at the bottom of an atomization tank containing a liquid to be atomized, thereby generating ultrasonic waves and generating a liquid column on the liquid surface directly above the ultrasonic vibrator, thereby atomizing the liquid; a liquid flow formation step of recovering droplets scattered from the liquid column and forming a downward liquid flow; and a bubble removal step of releasing the liquid flow near the vibration surface of the ultrasonic vibrator to remove air bubbles on the vibration surface.

[0024] Therefore, according to the invention described in claim 9, in the liquid flow forming step, the liquid flow formed by droplets scattered from the liquid column is released near the vibration surface of the ultrasonic vibrator in the bubble removing step, thereby removing bubbles on the vibration surface. As a result, oscillation occurs with the liquid in reliable contact with the vibration surface, preventing the ultrasonic vibrator from running dry, and thus preventing breakdown of the ultrasonic vibrator.

[0025] The invention described in claim 10 is an ultrasonic atomization method comprising: an atomization step of supplying high-frequency power to an ultrasonic vibrator placed at the bottom of an atomization tank containing a liquid to be atomized, thereby generating ultrasonic waves and generating a liquid column on the liquid surface directly above the ultrasonic vibrator, thereby atomizing the liquid; a liquid collection step of recovering droplets scattered from the liquid column and temporarily storing the liquid, which is a collection of droplets; a liquid flow formation step of rapidly releasing the accumulated liquid to form a downward liquid flow; and a bubble removal step of releasing the liquid flow near the vibration surface of the ultrasonic vibrator to remove air bubbles on the vibration surface.

[0026] Therefore, according to the invention described in claim 10, in the liquid flow forming step, a liquid flow formed by droplets scattered from the liquid column is released near the vibration surface of the ultrasonic vibrator in the bubble removing step, thereby removing bubbles on the vibration surface. As a result, oscillation occurs while the liquid is in reliable contact with the vibration surface, preventing the ultrasonic vibrator from running dry, thereby preventing malfunction of the ultrasonic vibrator. Furthermore, the liquid, which is a collection of droplets collected in the liquid collecting step, flows all at once in the liquid flow forming step, forming a powerful liquid flow. This allows the powerful liquid flow to collide with the vibration surface of the ultrasonic vibrator, thereby reliably removing bubbles attached to the vibration surface. [Effects of the Invention]

[0027] As described above in detail, according to the inventions set forth in claims 1 to 10, it is possible to prevent the ultrasonic vibrator from running dry without increasing the complexity or size of the entire device. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic cross-sectional view showing an ultrasonic atomization device according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the ultrasonic atomization device. [Figure 3] A photograph showing the ultrasonic transducer with the droplet collection tube installed, 10 minutes after the start of operation. [Figure 4] A photograph showing the ultrasonic transducer with the droplet collection tube installed, 20 minutes after the start of operation. [Figure 5] This is a photograph showing the ultrasonic transducer with the droplet collection tube installed 30 minutes after the start of operation. [Figure 6] A photograph showing the ultrasonic transducer with the droplet collection tube installed, one hour after the start of operation. [Figure 7] A photograph showing the ultrasonic transducer with the droplet collection tube removed, taken one hour after the start of operation. [Figure 8] A photograph showing the ultrasonic transducer 10 minutes after the start of operation without the droplet collection tube installed. [Figure 9] A photograph showing the ultrasonic transducer 20 minutes after the start of operation without the droplet collection tube installed. [Figure 10] A photograph showing the ultrasonic transducer 40 minutes after the start of operation without the droplet collection tube installed. [Figure 11] FIG. 10 is a cross-sectional view showing the ultrasonic transducer one hour after the start of operation without the droplet recovery tube installed. [Figure 12] FIG. 10 is a schematic cross-sectional view showing an ultrasonic atomization device according to a second embodiment. [Figure 13] FIG. 10 is a schematic cross-sectional view showing an ultrasonic atomization device according to another embodiment. [Figure 14] 10A and 10B are schematic diagrams showing a droplet recovery tube according to another embodiment. [Figure 15] FIG. 10 is a schematic diagram showing a droplet recovery pipe in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] [First embodiment] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention, which is an ultrasonic atomization device, will be described below in detail with reference to the drawings.

[0030] As shown in FIG. 1, the ultrasonic atomization device 10 includes an atomization tank 11 for containing the liquid W1 to be atomized. The ultrasonic atomization device 10 atomizes the liquid W1 by irradiating the liquid W1 in the atomization tank 11 with ultrasonic waves S1. The atomization tank 11 is generally rectangular and has a bottom 12 and a pair of opposing side walls 13 and 14. In this embodiment, hypochlorous acid water is used as the liquid W1. For this reason, the atomization tank 11, which is a component that comes into contact with the liquid W1, is made of a material that is resistant to hypochlorous acid water, such as an acrylic resin, acrylonitrile butadiene styrene resin (ABS resin), polypropylene resin (PP resin), or polyethylene resin (PE resin).

[0031] The ultrasonic atomization device 10 also includes an ultrasonic vibrator 20. More specifically, a recess 16 that opens into the internal space 15 of the atomization tank 11 is formed in the center of the bottom 12 of the atomization tank 11. The recess 16 is circular in plan view, and the ultrasonic vibrator 20 is installed on the bottom surface. The ultrasonic vibrator 20 of this embodiment emits (outputs) ultrasonic waves S1 with a frequency of 2.4 MHz from a vibration surface 21. This generates a liquid column W3 on the liquid surface W2 directly above the ultrasonic vibrator 20, atomizing the liquid W1. The ultrasonic vibrator 20 is disk-shaped and has a bonding surface that is in surface contact with the bottom surface of the recess 16 and a non-bonding surface (vibration surface 21) located on the opposite side of the bonding surface, and is made of a piezoelectric ceramic material or the like.

[0032] 1, the ultrasonic atomization device 10 is provided with a droplet recovery pipe 30 in the atomization tank 11. The droplet recovery pipe 30 recovers droplets W4 scattered from the liquid column W3 to form a downward liquid flow W5, which is then released near the vibration surface 21 of the ultrasonic vibrator 20. The droplet recovery pipe 30 has a lower end opening 31, a liquid reservoir section 32 which is an upper end opening, and a tube 33 (tube body) connecting the lower end opening 31 and the liquid reservoir section 32. The lower end opening 31 is located at a position lower than the liquid level W2 of the liquid W1, and the liquid reservoir section 32 is located at a position higher than the liquid level W2.

[0033] Furthermore, the droplet recovery tube 30 is generally positioned to avoid a position directly above the ultrasonic vibrator 20, except for the lower end opening 31. The lower end opening 31 is positioned close to the vibration surface 21 at a position that avoids a position directly above the center C1 of the ultrasonic vibrator 20. More specifically, the lower end opening 31 is formed integrally with the lower end of the tube 33, and is positioned facing diagonally downward (lower left in FIG. 1) so as to face the center C1. The lower end opening 31 is positioned close to the outer periphery of the vibration surface 21 of the ultrasonic vibrator 20, with a distance of approximately 2 to 3 mm from the vibration surface 21.

[0034] 1, the liquid reservoir 32 has a circular upper opening in a plan view and an expanded diameter with a larger cross-sectional area than the lower opening 31. Specifically, the lower part of the liquid reservoir 32 is connected to the upper end of the tube 33, and the liquid reservoir 32 is funnel-shaped with a cross-sectional area that gradually increases from bottom to top. Therefore, the liquid reservoir 32 has an open top, i.e., a shape that can temporarily collect droplets W4 scattered from the liquid column W3. Furthermore, the liquid reservoir 32 is positioned so as not to entirely surround the liquid column generation region A1, which is the region above the liquid level W2 where the liquid column W3 is generated, and is offset laterally to avoid the liquid column generation region A1.

[0035] The tube 33 is a flexible, transparent tube, and its cross-sectional area is equal to the cross-sectional area of ​​the lower end opening 31. The tube 33 has a shape in which the lower end is bent obliquely downward (toward the lower left in FIG. 1). The inclination angle of the tube 33 with respect to the vibration surface 21 of the ultrasonic vibrator 20 is, for example, 10° to 90°. A liquid flow W5 formed from the droplets W4 flows within the tube 33. Here, the tube 33 can be formed from a resin material such as polyvinyl chloride resin (PVC resin), polyethylene resin (PE resin), polybutadiene resin (BDR resin), polyurethane resin (PU resin), polyolefin resin (PO resin), polytetrafluoroethylene resin (PTFE resin), or silicone rubber.

[0036] Next, the electrical configuration of the ultrasonic atomization device 10 will be described.

[0037] 2, the ultrasonic atomization device 10 is provided with an oscillation substrate (not shown), and an electric circuit 40 is formed on the oscillation substrate. The electric circuit 40 includes an ultrasonic oscillation circuit 41, a drive circuit 42, and an output circuit 43.

[0038] The ultrasonic oscillation circuit 41 is electrically connected to the ultrasonic vibrator 20 via a drive circuit 42 and an output circuit 43. The ultrasonic oscillation circuit 41 outputs (supplies) high-frequency power from the output circuit 43 to the ultrasonic vibrator 20 to generate vibrations. As a result, the ultrasonic vibrator 20 irradiates the liquid W1 in the atomization tank 11 with ultrasonic waves S1. In addition, the drive circuit 42 has a function of guiding the high-frequency power output from the ultrasonic oscillation circuit 41 to the output circuit 43.

[0039] 2, the ultrasonic atomization device 10 of this embodiment is equipped with a control device 51. The control device 51 is configured by a well-known computer including a CPU, ROM, RAM, etc. The control device 51 is electrically connected to the ultrasonic oscillation circuit 41 and drives the ultrasonic oscillation circuit 41.

[0040] Next, a method for atomizing the liquid W1 using the ultrasonic atomization device 10 will be described.

[0041] First, after placing the liquid W1 in the atomization tank 11, the power supply (not shown) of the ultrasonic atomization device 10 is turned on. Next, the control device 51 performs the atomization step process, supplying high-frequency power to the ultrasonic vibrator 20 to generate ultrasonic waves S1, and generating a liquid column W3 on the liquid surface W2 directly above the ultrasonic vibrator 20, thereby atomizing the liquid W1. Specifically, the control device 51 controls the ultrasonic oscillation circuit 41 to output high-frequency power for generating vibrations in the ultrasonic vibrator 20. The high-frequency power output from the ultrasonic oscillation circuit 41 is input to the output circuit 43 via the drive circuit 42.

[0042] The high-frequency power is then applied to the ultrasonic vibrator 20, causing it to vibrate. As a result, ultrasonic waves S1 are radiated into the liquid W1 from the vibration surface 21 of the ultrasonic vibrator 20. The ultrasonic waves S1 radiated from the ultrasonic vibrator 20 propagate through the liquid W1 and reach the liquid surface W2. At this time, ultrasonic energy is concentrated at a position above the ultrasonic vibrator 20 on the liquid surface W2, causing the liquid W1 to rise and become a mass (i.e., liquid column W3). Then, at the tip of the raised liquid W1, a portion of the liquid W1 is atomized and scattered as mist (droplets W4). As a result, the humidity of the space in which the ultrasonic atomization device 10 is installed is controlled.

[0043] When atomizing the liquid W1 as described above, the control device 51 vibrates the ultrasonic vibrator 20 while the ultrasonic oscillation circuit 41 is outputting high-frequency power. However, while the ultrasonic vibrator 20 is operating, air bubbles 22 (see FIGS. 3 to 11) continue to adhere to the vibration surface 21 of the ultrasonic vibrator 20. In particular, the air bubbles 22 adhering to the center C1 of the vibration surface 21 prevent the liquid W1 from contacting the vibration surface 21 and cause the ultrasonic vibrator 20 to run dry. Therefore, the air bubbles 22 must be removed.

[0044] Therefore, in this embodiment, a liquid collecting step and a liquid flow forming step are performed in addition to the atomization step. In the liquid collecting step, the droplets W4 scattered from the liquid column W3 are collected, and the liquid W1, which is an aggregate of the droplets W4, is temporarily collected. Specifically, when a large number of droplets W4 are scattered from the liquid column W3, some of the scattered droplets W4 adhere to the inner surface of the liquid reservoir 32 of the droplet recovery pipe 30. Thereafter, as the number of droplets W4 collecting in the liquid reservoir 32 increases, the liquid W1, which is an aggregate of the droplets W4, is generated.

[0045] In the subsequent liquid flow forming step, the accumulated liquid W1 is caused to flow in one go, forming a downward liquid flow W5. Specifically, when the number of droplets W4 accumulated in the liquid reservoir 32 increases and liquid W1 is generated, the liquid W1 becomes liquid flow W5 due to the action of gravity and flows downward in one go on the inner surface of the liquid reservoir 32. Then, when the liquid flow W5 reaches the lower end of the liquid reservoir 32, it flows into the tube 33 from the upper end thereof and falls within the tube 33.

[0046] Next, a bubble removal step is performed in which liquid flow W5 is emitted near the vibration surface 21 of the ultrasonic vibrator 20 to remove the bubbles 22 on the vibration surface 21. Specifically, the liquid flow W5 that has fallen inside the tube 33 is emitted from the lower end opening 31 and falls onto the vibration surface 21 of the ultrasonic vibrator 20. Then, the liquid flow W5 collides with the bubbles 22 adhering to the vibration surface 21, causing the bubbles 22 to pop or be blown away, thereby removing the bubbles 22.

[0047] Next, the evaluation method and results of the ultrasonic atomization device will be described.

[0048] First, an ultrasonic atomization device identical to the ultrasonic atomization device 10 of this embodiment was prepared, and liquid was placed in the atomization tank 11 of the ultrasonic atomization device. Next, the ultrasonic vibrator 20 provided in the ultrasonic atomization device was vibrated, and as a result, air bubbles 22 were attached to the vibration surface 21 of the ultrasonic vibrator 20.

[0049] Next, we verified to what extent the bubbles 22 could be removed when the ultrasonic vibrator 20 was driven with the droplet recovery tube 30 installed in the atomization tank 11. Fig. 3 shows the ultrasonic vibrator 20 10 minutes after the start of operation, Fig. 4 shows the ultrasonic vibrator 20 20 minutes after the start of operation, Fig. 5 shows the ultrasonic vibrator 20 30 minutes after the start of operation, and Fig. 6 shows the ultrasonic vibrator 20 1 hour after the start of operation. Fig. 7 shows the ultrasonic vibrator 20 photographed with the droplet recovery tube 30 removed 1 hour after the start of operation.

[0050] We also verified how the bubbles 22 change when the ultrasonic vibrator 20 is driven without the droplet recovery pipe 30 installed in the atomization tank 11. Fig. 8 shows the ultrasonic vibrator 20 10 minutes after the start of operation, Fig. 9 shows the ultrasonic vibrator 20 20 minutes after the start of operation, Fig. 10 shows the ultrasonic vibrator 20 40 minutes after the start of operation, and Fig. 11 shows the ultrasonic vibrator 20 1 hour after the start of operation.

[0051] As a result, it was confirmed that when the droplet recovery pipe 30 was installed (see FIGS. 3 to 7), bubbles 22 remained on the outer periphery of the vibrating surface 21 even one hour after the start of operation (see FIGS. 6 and 7). However, it was confirmed that the bubbles 22 attached to the center C1 of the vibrating surface 21 were sufficiently removed even after only ten minutes had passed since the start of operation (see FIG. 3).

[0052] On the other hand, when the droplet recovery pipe 30 is not installed (see Figures 8 to 11), it was confirmed that not only large bubbles 22 remain on the outer periphery of the vibration surface 21, but also fine bubbles 22 remain in the center C1 of the vibration surface 21, even one hour after the start of operation (see Figure 11). From the above, it was proven that if the droplet recovery pipe 30 is installed in the atomization tank 11, the bubbles 22 in the center C1 can be removed.

[0053] Therefore, according to this embodiment, the following effects can be obtained.

[0054] (1) In the ultrasonic atomization device 10 of this embodiment, the liquid flow W5 formed by the droplets W4 scattered from the liquid column W3 is released from the droplet recovery tube 30 near the vibration surface 21 of the ultrasonic vibrator 20, thereby removing, in particular, the air bubbles 22 attached to the center C1 of the vibration surface 21. As a result, oscillation occurs with the liquid W1 reliably in contact with the center C1 of the vibration surface 21, preventing the ultrasonic vibrator 20 from running dry, thereby preventing malfunction of the ultrasonic vibrator 20. Furthermore, as a result of the removal of the air bubbles 22, oscillation becomes possible with the liquid W1 in contact with the entire center C1, and a large amount of the liquid W1 is atomized. In other words, a decrease in the amount of atomization due to the adhesion of the air bubbles 22 can be prevented.

[0055] (2) In this embodiment, by providing the droplet recovery pipe 30, the pressurized liquid supply device of Patent Document 1, which pressure-feeds pressurized liquid near the vibration surface 21, is not required, so the ultrasonic atomization device 10 as a whole can be prevented from becoming too complicated and large, and costs can be kept down.

[0056] (3) In this embodiment, the liquid reservoir 32 of the droplet recovery pipe 30 has a structure in which the cross-sectional area gradually decreases from the top to the bottom. Therefore, a tube 33 with a small cross-sectional area can be selected for connection to the bottom of the liquid reservoir 32. As a result, the flow velocity of the liquid flow W5 passing through the tube 33 increases, and the powerful liquid flow W5 can be caused to collide with the vibration surface 21 of the ultrasonic vibrator 20. Therefore, the air bubbles 22 adhering to the vibration surface 21 can be reliably removed.

[0057] [Second embodiment] A second embodiment of the present invention will now be described with reference to the drawings, focusing on differences from the first embodiment.

[0058] 12, the ultrasonic atomization device 60 of this embodiment differs from the first embodiment in that it is provided with a deer-scare mechanism 61 above the droplet recovery pipe 30. That is, the deer-scare mechanism 61 of this embodiment is a mechanism that collects droplets W4 scattered from the liquid column W3 above the droplet recovery pipe 30 and intermittently supplies liquid W1, which is an aggregate of the collected droplets W4, to the droplet recovery pipe 30.

[0059] Specifically, the deer-scare mechanism 61 includes a cylindrical container 62 and a pair of support members 63. The open end of the cylindrical container 62 at the tip end (the left end in FIG. 12) is inclined at a predetermined angle relative to the axial direction of the cylindrical container 62. A rotating shaft 64 that penetrates the cylindrical container 62 in the radial direction is provided at a location closer to the base end (the right end in FIG. 12) than the center of the cylindrical container 62. Both ends of the rotating shaft 64 are supported by a pair of support members 63. Both support members 63 are erected on fixing parts 65 that extend outward (to the right in FIG. 12) from the upper end of the side wall 14 of the atomization tank 11. As a result, the cylindrical container 62 is rotatably supported by both support members 63. The cylindrical container 62 is configured to receive the liquid droplets W4 from the tip end. When the amount of stored liquid W1 (droplets W4) reaches a predetermined amount, the cylindrical container 62 rotates around the rotation axis 64 so that the tip side lowers (see the dashed line portion in Figure 12), causing the liquid W1 to flow out.

[0060] Next, a method for atomizing the liquid W1 using the ultrasonic atomization device 60 will be described.

[0061] First, the control device 51 performs the atomization step, supplying high-frequency power to the ultrasonic vibrator 20 to generate ultrasonic waves S1, and atomizing the liquid W1 by generating a liquid column W3 on the liquid surface W2 directly above the ultrasonic vibrator 20.

[0062] When the liquid W1 is atomized, bubbles 22 (see FIGS. 3 to 11) continue to adhere to the vibration surface 21 of the ultrasonic vibrator 20. The bubbles 22 adhering to the vibration surface 21 can cause the ultrasonic vibrator 20 to run dry, so it is necessary to remove the bubbles 22. Therefore, in this embodiment, a liquid accumulation step and a liquid flow formation step are performed in addition to the atomization step.

[0063] In the liquid collecting step, the droplets W4 scattered from the liquid column W3 are collected, and the liquid W1, which is an aggregate of the droplets W4, is temporarily collected. Specifically, when a large number of droplets W4 are scattered from the liquid column W3, some of the scattered droplets W4 adhere to the inner surface of the cylindrical container 62 of the deer-scare mechanism 61. Thereafter, as the number of droplets W4 collecting in the cylindrical container 62 increases, the liquid W1, which is an aggregate of the droplets W4, is generated.

[0064] In the subsequent liquid flow forming step, the accumulated liquid W1 is caused to flow all at once, forming a downward liquid flow W5. Specifically, as the number of droplets W4 accumulated in the cylindrical container 62 increases and liquid W1 is generated, the cylindrical container 62 rotates about the rotation axis 64 due to the weight of the liquid W1, with the tip side (the left end side in FIG. 12 ) lowering. The liquid W1 in the cylindrical container 62 then falls as a liquid flow W5 all at once and flows into the liquid reservoir 32 of the droplet recovery tube 30. Some of the droplets W4 scattered from the liquid column W3 do not adhere to the inner surface of the cylindrical container 62, but instead adhere directly to the inner surface of the liquid reservoir 32. The liquid flow W5 that falls from the cylindrical container 62 into the liquid reservoir 32 then becomes a liquid flow W5 that also includes the droplets W4 already adhered to the liquid reservoir 32, and flows downward along the inner surface of the liquid reservoir 32. Furthermore, the liquid flow W5 that has reached the lower end of the liquid reservoir 32 falls inside the tube 33.

[0065] Next, a bubble removal step is performed in which a liquid flow W5 is emitted in the vicinity of the vibration surface 21 of the ultrasonic vibrator 20 to remove the bubbles 22 on the vibration surface 21.

[0066] Therefore, in the ultrasonic atomization device 60 of this embodiment, the liquid W1, which is a collection of droplets W4 collected by the deer-scare mechanism 61, flows all at once as it falls into the droplet recovery pipe 30, becoming a powerful liquid flow W5. Moreover, the liquid flow W5 that falls from the cylindrical container 62 into the liquid reservoir 32 becomes a liquid flow W5 that also includes the droplets W4 already attached to the liquid reservoir 32, and therefore the momentum of the liquid flow W5 becomes even stronger. This allows the powerful liquid flow W5 to be released from the droplet recovery pipe 30 and collide with the vibration surface 21 of the ultrasonic vibrator 20. Therefore, the air bubbles 22 attached to the vibration surface 21 can be reliably removed.

[0067] The above embodiment may be modified as follows.

[0068] As shown in FIG. 13, the ultrasonic atomization device 70 may further include a nozzle-shaped cover member 71 installed on the bottom 12 of the atomization tank 11 in a state where it covers the ultrasonic vibrator 20. The cover member 71 has multiple (four here) through-holes 74 that connect the inner surface 72 and outer surface 73 of the cover member 71. The lower-end opening 31 of the tube 33 of the droplet recovery pipe 30 is inserted and fixed into one of the through-holes 74. The remaining through-holes 74 are discharge holes for discharging the liquid flow W5 released from the lower-end opening 31 of the tube 33 to the outside of the cover member 71. This configuration allows the tube 33 to be securely fixed. Also, it is possible to prevent the lower-end opening 31 at the tip of the tube 33 from shifting in position.

[0069] The droplet recovery pipe 30 in the above embodiment has a tube 33 with a diagonally bent lower end. However, the droplet recovery pipe 30 may have a tube 81 with a dogleg bent lower end (see FIG. 14(a)), or a tube 82 with a right-angle bent lower end (see FIG. 14(b)).

[0070] The droplet recovery pipe 30 in the above embodiment has a funnel-shaped reservoir 32 whose cross-sectional area gradually increases from the bottom to the top. However, as shown in Figure 15, the droplet recovery pipe 30 may have a reservoir 83 whose cross-sectional area is constant from the bottom to the top.

[0071] In each of the above embodiments, a plurality of ultrasonic vibrators 20 may be installed on the bottom 12 of the atomization tank 11. In this case, one droplet recovery pipe 30 (and deer scare mechanism 61) may be provided for each ultrasonic vibrator 20, or one droplet recovery pipe 30 (and deer scare mechanism 61) may be provided for a plurality of ultrasonic vibrators 20.

[0072] In the above embodiments, the recess 16 is formed in the bottom 12 of the atomization tank 11, and the ultrasonic vibrator 20 is installed on the bottom surface of the recess 16. However, the installation manner of the ultrasonic vibrator 20 may be changed. For example, the recess 16 may be omitted, and the ultrasonic vibrator 20 may be installed on the bottom 12 of the atomization tank 11. Note that although the recess 16 in the above embodiment is formed in the center of the bottom 12, it may also be formed on the outer periphery of the bottom 12.

[0073] In the above embodiment, hypochlorous acid water is used as the liquid W1 to be put into the atomization tank 11, but this is not limitative and pure water, tap water, or the like may also be used.

[0074] Next, in addition to the technical ideas set forth in the claims, the technical ideas grasped by the above-described embodiments will be listed below.

[0075] (1) The ultrasonic atomization device according to any one of claims 1 to 7, further comprising a nozzle-shaped cover member installed on the bottom of the atomization tank in a state of covering the ultrasonic vibrator, and the lower end opening is inserted and fixed into a through hole that connects the inner and outer surfaces of the cover member. This configuration allows the droplet recovery tube having the lower end opening to be securely fixed, and also prevents the lower end opening from shifting out of position.

[0076] (2) The ultrasonic atomizer according to claim 3, wherein the upper opening is a funnel-shaped liquid reservoir that can temporarily store the droplets.

[0077] (3) The ultrasonic atomization device according to claim 7, wherein the tube is flexible.

[0078] (4) The ultrasonic atomization device according to claim 2, wherein the droplet recovery pipe is arranged so as to avoid a position directly above the ultrasonic vibrator, except for the lower end opening.

[0079] (5) In the technical idea (4), an ultrasonic atomization device characterized in that the lower end opening of the droplet recovery tube is arranged facing diagonally downward so as to avoid a position directly above the ultrasonic vibrator and to be close to its outer periphery. [Explanation of symbols]

[0080] 10,60,70…Ultrasonic atomization device 11...Atomization tank 12...Bottom of atomization tank 20...Ultrasonic vibrator 21...Vibration surface of ultrasonic vibrator 22...Air bubbles 30...Droplet collection tube 31...Lower end opening 32, 83...Liquid reservoir as upper opening 33, 81, 82...Tube as the main body 61…Shikashi Mechanism A1: Liquid column generation region C1: Center of ultrasonic transducer S1…Ultrasonic W1…liquid W2: Liquid level W3…liquid column W4…Droplet W5…liquid flow

Claims

1. an atomization tank for containing a liquid to be atomized; an ultrasonic vibrator installed at the bottom of the atomization tank; and an ultrasonic atomization device that supplies high-frequency power to the ultrasonic vibrator to generate ultrasonic waves and generate a liquid column on the liquid surface directly above the ultrasonic vibrator, thereby atomizing the liquid. The atomization tank is provided with a droplet recovery pipe that recovers droplets scattered from the liquid column to form a downward liquid flow and discharges the liquid flow near the vibration surface of the ultrasonic vibrator. An ultrasonic atomization device characterized by:

2. The droplet recovery tube is a lower end opening disposed at a position lower than the liquid level; an upper end opening that is disposed at a position higher than the liquid level and has an expanded diameter shape with a cross-sectional area larger than that of the lower end opening; a pipe body connecting the lower end opening and the upper end opening; 2. The ultrasonic atomization device according to claim 1, further comprising:

3. 3. The ultrasonic atomization device according to claim 2, wherein the upper end opening is arranged so as not to entirely surround a liquid pillar generation region, which is a region above the liquid surface where the liquid pillar is generated, and so as to be offset laterally to avoid the liquid pillar generation region.

4. 4. The ultrasonic atomizer according to claim 3, wherein the upper opening is a funnel-shaped liquid reservoir portion whose cross-sectional area gradually increases from the bottom to the top.

5. The ultrasonic atomization device according to claim 2, characterized in that the lower end opening is integrally formed at the lower end of the tube body and is arranged close to the vibration surface while avoiding a position directly above the center of the ultrasonic vibrator.

6. 6. The ultrasonic atomization device according to claim 5, wherein the lower end opening is disposed facing obliquely downward so as to face the center of the ultrasonic vibrator.

7. 7. The ultrasonic atomization device according to claim 6, wherein the pipe body is a tube having a shape in which a lower end is bent obliquely downward, and the lower end opening is integrally formed at the lower end of the tube.

8. The ultrasonic atomization device according to any one of claims 1 to 7, further comprising a scare mechanism that collects the droplets scattered from the liquid column at an upper position of the droplet recovery tube and intermittently supplies the liquid, which is a collection of the collected droplets, to the droplet recovery tube.

9. an atomization step in which high-frequency power is supplied to an ultrasonic vibrator installed at the bottom of an atomization tank containing a liquid to be atomized, thereby generating ultrasonic waves and generating a liquid column on the liquid surface directly above the ultrasonic vibrator, thereby atomizing the liquid; a liquid flow forming step of collecting droplets scattered from the liquid column and forming a downward liquid flow; a bubble removal step of removing bubbles from the vibration surface by discharging the liquid flow near the vibration surface of the ultrasonic vibrator; An ultrasonic atomization method comprising:

10. an atomization step in which high-frequency power is supplied to an ultrasonic vibrator installed at the bottom of an atomization tank containing a liquid to be atomized, thereby generating ultrasonic waves and generating a liquid column on the liquid surface directly above the ultrasonic vibrator, thereby atomizing the liquid; a liquid collecting step of collecting droplets scattered from the liquid column and temporarily collecting the liquid that is a collection of the droplets; a liquid flow forming step of flushing the accumulated liquid at once to form a downward liquid flow; a bubble removal step of removing bubbles from the vibration surface by discharging the liquid flow near the vibration surface of the ultrasonic vibrator; An ultrasonic atomization method comprising:

Images