JP6488514B2 - Atomizer - Google Patents

Description

  The present invention relates to an atomizer.

  Atomization devices that atomize liquids are used in a wide range of fields, from familiar items such as humidification, insecticide sprays, and oil fan heaters to spray drying of foods, fertilizers, paints, and the like. Among such atomizers, an atomizer using ultrasonic waves is one of those used industrially, and is used for separation and concentration of droplets. Ultrasonic atomization has the advantage of significantly reducing energy consumption compared to distillation methods that heat and separate and concentrate.

  As an atomizing apparatus using ultrasonic waves, one that directly touches a vibration surface of a diaphragm with a liquid to be atomized is known (see, for example, Patent Document 1 and Patent Document 2). The atomization method in such an atomization apparatus is a method using capillary waves, and is a method in which the wave front of the liquid surface wave is broken by vibration to generate minute droplets.

JP 2003-71343 A Japanese Patent No. 3368501

However, in an atomization apparatus employing such an atomization method, since the particle size of the atomized particles depends on the frequency, for example, when trying to obtain a small (fine) particle size, the frequency is increased and vibration is performed. It is necessary to make the surface small, so that the atomization efficiency is lowered.
In addition to such an atomization method, an atomization method using a squeeze film effect is also known. In this method, a minute gap is provided between the vibrating surface, the minute gap is filled with the droplet, and the droplet is atomized by a pressure difference generated by expanding and contracting the minute gap.
However, in the atomization apparatus adopting such an atomization method, although the atomization particles having a small particle diameter can be obtained by driving at a low frequency, the structure is complicated such that a valve mechanism is required. There is.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an atomization apparatus having a simple structure and high atomization efficiency.

  An atomization device according to the present invention includes an ultrasonic vibration device including a vibrator and a plurality of vibration plates coupled to the ultrasonic vibration device, and the plurality of vibration plates each vibrate the vibration of the vibrator. It is configured to vibrate in a mutually different vibration mode in conjunction with each other, and has a liquid supply means that is disposed through a predetermined minute gap in a state of facing each other and supplies a liquid to the minute gap. To do.

  In the atomization device, it is preferable that the plurality of diaphragms include two diaphragms arranged to face each other.

  In the atomization apparatus, the liquid supply means includes a supply pipe for supplying a liquid, and the supply pipe is disposed at a vibration node position of the vibration plate toward the minute gap. An opening is preferred.

  In the atomization device, it is preferable that the ultrasonic vibration device is a single device, and a plurality of vibration plates are connected to the single ultrasonic vibration device.

  According to the atomizing device of the present invention, the plurality of diaphragms connected to the ultrasonic vibrator are configured to vibrate in different vibration modes in conjunction with the vibration of the vibrator. It is possible to form a portion where the pressure is high and a portion where the pressure is low in the minute gap, so that the atomization of the liquid can be performed with high efficiency between the diaphragms, and the atomized particles can be reduced in size. In addition, since the ultrasonic vibration device, the plurality of vibration plates, and the liquid supply means are included, the structure is simple, and thus the atomization device can be manufactured at low cost.

It is a front view of one Embodiment of the atomization apparatus which concerns on this invention. It is a figure which shows the mode of atomization in an experiment example.

Hereinafter, the atomization apparatus of the present invention will be described in detail with reference to the drawings. In the following drawings, the scale of each member is appropriately changed to make each member a recognizable size.
FIG. 1 is a front view of an atomizer according to the present invention, and in FIG. 1, reference numeral 1 denotes an atomizer.

  The atomizing device 1 atomizes a liquid, that is, atomizes, and includes an ultrasonic vibration device 2, two (a plurality of) vibration plates 3 and 3, and a liquid supply unit 4. Yes. Ultrasound generally refers to high-frequency sound that cannot be heard by humans, but may also refer to sound waves that are not intended to be heard even in the human audible range (about 20 Hz to 20 kHz). .

The ultrasonic vibration device 2 is formed including a vibrator 5, and the vibrator 5 vibrates the diaphragm 3 to generate ultrasonic vibration.
Specifically, the vibrator 5 is composed of an electromechanical conversion element such as a piezoelectric element, a magnetostrictive element, or an electrostrictive element. Among them, a bolt-clamped Langevin type transducer (BLT) is preferably used as the transducer 5 that generates strong ultrasonic waves. The vibrator 5 is driven by electric power supplied from a power supply circuit (power supply) (not shown).

  The vibrator 5 is connected to the diaphragms 3 and 3 via an exponential horn 6 and a uniform rod 7. The exponential horn 6 is attached to the vibrator 5 and amplifies the vibration by the vibrator 5 (increases the amplitude). The uniform rod 7 connects the exponential horn 6 and the diaphragms 3 and 3, and transmits the vibration amplified by the exponential horn 6 to the diaphragms 3 and 3.

  It should be noted that the distance from the vibrator 5 to the diaphragm 3 is a half wavelength (1/2 wavelength [λ / 2]) of vibration of the vibrator 5 in order to excite the diaphragms 3 and 3 in a desired mode. The length is set to be close to an integral multiple. In the present embodiment, the distance to the lower diaphragm 3 among the two diaphragms 3 and 3 arranged vertically as described later is an integral multiple of the half wavelength of the vibration of the vibrator 5. Therefore, the distance to the upper diaphragm 3 is slightly longer than this. However, the present invention is not limited to this, and the distance to the upper diaphragm 3 may be set to be an integral multiple of a half wavelength, and the distance to the middle position between the two diaphragms 3 and 3 may be set. The distance may be set to be an integral multiple of a half wavelength.

  The two diaphragms 3 and 3 are arranged in parallel with a predetermined minute gap in a state of facing each other, and are connected to the upper end of the uniform rod 7 in this state. These diaphragms 3 and 3 are all flexible diaphragms made of discs having the same diameter, and are fixed to the uniform rod 7 by screwing the central portions thereof to the uniform rod 7. That is, the uniform rod 7 has a female screw (not shown) formed on the upper end surface thereof, and the diaphragms 3 and 3 have a through hole (not shown) formed in the center thereof. .

  And the lower diaphragm 3 is arrange | positioned at the upper end of the uniform rod 7, the annular spacer 8 is arrange | positioned on it, and also the upper diaphragm 3 is arrange | positioned on it. At that time, the female screw of the uniform rod 7, the through hole of the lower diaphragm 3, the hole of the spacer 8, and the through hole of the upper diaphragm 3 are all arranged to communicate with each other. In this state, the male screw 9 is inserted into each hole and screwed into the female screw, whereby the two diaphragms 3 and 3 face each other in a predetermined minute gap (corresponding to the thickness of the spacer 8). It is connected to the upper end of the uniform rod 7 via a gap).

  The material of the diaphragm 3 is not particularly limited, and for example, a metal plate such as duralumin or titanium is used. The diaphragms 3 and 3 are configured to vibrate in different vibration modes in conjunction with the vibration of the vibrator 5. That is, although these diaphragms 3 and 3 are both formed to have the same diameter in this embodiment, they are formed to have different thicknesses, thereby interlocking with the single vibration of the single vibrator 5. They are designed to vibrate in different vibration modes.

  The difference in thickness between the diaphragms 3 and 3 is not particularly limited, and is appropriately set according to the properties of the liquid to be atomized, the diameter of the target atomized particles, and the like. That is, in order to make the target liquid atomized particles having a desired diameter, the condition is set such that the required power can be minimized, that is, the efficiency is high.

  In the present embodiment, the upper diaphragm 3 is particularly configured to be in a vibration mode that forms a nodal circle because a supply pipe 10 for supplying a liquid is disposed as will be described later. The knot circle can be confirmed by, for example, a Kradoni sand chart formed on the diaphragm 3 when the vibrator 5 is driven at an actual driving frequency. The sand chart of Kladoni is for seeing the mode of flexural vibration by spreading fine particles on the vibration surface, and the upper diaphragm 3 is so shaped that nodal circles are formed by such sand chart. Size (diameter) and thickness are determined.

  The spacer 8 is formed by, for example, a washer, and the width (distance) of the gap (small gap) between the upper and lower diaphragms 3 and 3 is determined by the thickness thereof. The minute gap is a portion that holds the liquid supplied by the liquid supply unit 4 and pressurizes the held liquid as will be described later. The width of the minute gap is not particularly limited, and is appropriately set according to the properties of the atomized liquid, the diameter of the target atomized particles, and the like. For example, the minute gap is formed on the order of several tens of μm to several hundreds of μm, that is, 10 μm or more and less than 1 mm.

  The liquid supply means 4 includes a liquid supply source 11 such as a microsyringe pump and a small-diameter supply pipe 10 made of an injection needle or the like connected to the liquid supply source 11. The liquid supply source 11 stores the liquid to be atomized and sends out the stored liquid continuously or intermittently. The liquid to be atomized is not particularly limited, and various liquids are used. For example, when the atomizing device of the present invention is applied to a humidifying device, water is used as the liquid, and when applied to an insecticidal spray, various chemicals are used and applied to an oil fan heater. Kerosene or the like is used. Moreover, when using industrially, various solutions are used.

  In the present embodiment, the supply pipe 10 is disposed on the upper diaphragm 3 of the two diaphragms 3. The upper diaphragm 3 is formed with a through hole (not shown) at a position on the above-described nodal circle, and the supply pipe 10 is inserted through the through hole. When a plurality of node circles are formed on the diaphragm 3, a through hole is formed on the node circle on the inner side (side closer to the uniform rod 7). Thereby, the influence of the supply pipe 10 on the atomization of the liquid in the minute gap is minimized.

  In the present embodiment, the supply pipe 10 has an outer diameter smaller than the inner diameter of the through hole, and is supported by a support member (not shown) so that the supply pipe 10 is inserted into the through hole so as not to contact the inner wall surface of the through hole. And opened toward the minute gap. Alternatively, a cushioning material such as a resin is interposed between the through hole and the supply pipe 10 so that the supply pipe 10 is disposed in the through hole without directly contacting the inner wall of the through hole and toward the minute gap. It is open. Thereby, the influence of the supply pipe 10 on the vibration mode of the diaphragm 3 is minimized.

  Further, the tip of the supply pipe 10 is disposed in the through hole so as not to protrude into the minute gap between the diaphragms 3 and 3. With such a configuration, the supply pipe 10 hardly affects the vibration mode of the diaphragm 3 as described above, and further does not impair the pressurization of the liquid by the diaphragms 3 and 3.

  In order to atomize the liquid by the atomizing device 1 having such a configuration, the vibration vibration device 5 is vibrated by driving the ultrasonic vibration device 2 to vibrate the diaphragms 3 and 3 in conjunction with the vibration. . At that time, although the lower diaphragm 3 and the upper diaphragm 3 are formed of circular plates with the same diameter, they have different thicknesses and vibrate in different vibration modes. That is, although the vibrator 5 is vibrated at a single frequency by the single ultrasonic vibration device 2, the thicknesses of the upper and lower diaphragms 3 and 3 are made different from each other. 3 can be vibrated in different vibration modes.

  In this way, the liquid is supplied in advance by the liquid supply means 4 to the minute gap between the diaphragms 3 and 3 that vibrate in different vibration modes, or by supplying the liquid after the ultrasonic vibration device 2 is driven. Fill liquid. When the liquid is supplied to the minute gap, the liquid easily wets and spreads throughout the minute gap due to the capillary phenomenon, and is held in the minute gap without leaking from the minute gap.

  By applying different vibrations to the liquid in the minute gap from the diaphragms 3 and 3 to form a high pressure portion and a low pressure portion in the minute gap, the liquid is atomized between the diaphragms 3 and 3. Atomized particles flow out between the outer peripheral end faces of 3, 3 and from the outer peripheral side opening of the minute gap.

Here, the minimum atomization power when water (liquid) was atomized was measured by changing the thickness of the two diaphragms 3 and 3 and the width (distance) of the minute gap as follows. Results are shown.
A duralumin disk having a diameter of 95 mm and a thickness of 3 mm was prepared as the upper diaphragm 3. Further, as the lower diaphragm 3, three kinds of duralumin disks each having a diameter of 95 mm and a thickness of 1 mm, 2 mm, and 3 mm were prepared.

A through hole having a diameter of 1 mm is formed in the inner diaphragm 3 at the position of the inner circular circle, and water (liquid) is injected into the through hole from the injection needle (supply pipe 10) of the syringe. .
In addition, spacers 8 having a thickness of 0.1 mm and 0.5 mm were prepared, and thereby the width (distance) of the minute gap was made two types of 0.1 mm and 0.5 mm.
Then, atomization was performed by changing the spacer 8 in two ways and the lower diaphragm 3 in three ways with respect to the upper diaphragm 3 having a thickness of 3 mm.

  The atomization was performed by filling the minute gap with water in advance with a syringe and increasing the supply voltage to the vibrator 5. And the minimum electric power when the atomization of water was observed from the gap | interval was measured. In addition, in order to make the resonance frequency close to the same frequency as that of the vibrator 5, the length of the uniform bar 7 was adjusted for each condition. Measurement was performed three times under each condition, and an average value was obtained. The results obtained are shown in the table below.

  As shown in the table, when the thickness of the spacer 8 is 0.1 mm and the thickness of the lower diaphragm 3 is 2 mm or less, the minimum atomization voltage is 1 W or less, and therefore the atomization efficiency is increased. I understood. Further, the minimum atomization power varies greatly when the thickness of the lower diaphragm 3 is 2 mm and 3 mm for both the spacer 8 having a thickness of 0.1 mm and 0.5 mm. It was found that the minimum atomization voltage was small.

Therefore, the thickness of the upper diaphragm 3 and the lower diaphragm 3 is different, and the thickness of the upper diaphragm 3 and the lower diaphragm 3 is higher in a device that vibrates in different vibration modes. It was found that the minimum atomization power is low and the atomization efficiency is high as compared with devices that are 3 mm in length and vibrate in substantially the same vibration mode.
The state of atomization is shown in FIG. In FIG. 2, it is binarized for easy viewing.

  In the atomization apparatus 1 of the present embodiment, the two diaphragms 3 and 3 are configured to vibrate in mutually different vibration modes in conjunction with the vibration of the vibrator 5. A high pressure portion and a low pressure portion can be formed in the minute gap between the three plates, so that the liquid can be atomized between the diaphragms 3 and 3 with high efficiency. The diameter can also be increased. Further, since the atomizing device 1 is constituted by the ultrasonic vibration device 2, the plurality of vibration plates 3, and the liquid supply means 4, the structure is simplified, and therefore the atomizing device 1 is manufactured at a low cost. Can do.

Moreover, since the several diaphragm 3 is formed of the two diaphragms 3 and 3 arrange | positioned facing each other, the atomization apparatus 1 can be made a simpler structure.
Furthermore, since the ultrasonic vibration device 2 is constituted by a single device, and two (plural) diaphragms 3 and 3 are connected to the single ultrasonic vibration device, the atomization device 1 can be simplified. Structure.

  In addition, since the supply pipe 10 of the liquid supply means 4 is disposed at the vibration node position of the diaphragm 3 and opened toward the minute gap, the supply pipe 10 may affect the vibration of the diaphragm 3. Therefore, the influence of the supply pipe 10 on the atomization of the liquid in the minute gap can be minimized. Therefore, the atomization of the liquid can be performed with high efficiency.

  The preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above-described embodiments. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the embodiment, two diaphragms 3 are used, but three or more diaphragms may be used, and these may be arranged in parallel to the thickness direction. By arranging three or more diaphragms in parallel in the thickness direction as described above, a plurality of minute gaps between the diaphragms facing each other can be formed, so that the atomization efficiency can be further improved.

Moreover, in the said embodiment, in order to make the vibration mode of the two diaphragms 3 and 3 differ, these thicknesses are changed, However, this invention is not limited to this, For example, a diameter (size) The vibration modes may be made different by changing the shape or changing the shape or material.
Furthermore, by superimposing vibrations of different frequencies from the ultrasonic vibration device 2 and applying the vibrations to the plurality of diaphragms, the plurality of diaphragms resonate and vibrate at frequencies that are easy to shake, thereby The vibration mode may be varied.

  In the above-described embodiment, two (a plurality of) diaphragms 3 and 3 are connected to a single ultrasonic vibration device 2. For example, two ultrasonic vibration devices are prepared, and each of these devices has a single vibration. Atomization may be performed in the minute gap by providing a plate and forming the minute gap by making these diaphragms face each other. In such a configuration, the vibration modes of the two diaphragms can be easily made different by vibrating the two ultrasonic vibration devices in different modes.

In the above embodiment, the supply pipe of the liquid supply means is disposed on the upper diaphragm of the two diaphragms. However, the present invention is not limited to this, and is disposed on, for example, the lower diaphragm 3. Alternatively, the supply pipe may be arranged directly toward the outer peripheral opening of the minute gap without being arranged on the diaphragm.
Further, in the above-described embodiment, two (a plurality of) diaphragms are arranged up and down to form a horizontal gap that expands in the horizontal direction. You may do it.

DESCRIPTION OF SYMBOLS 1 ... Atomization apparatus, 2 ... Ultrasonic vibration apparatus, 3 ... Vibration plate, 4 ... Liquid supply means, 5 ... Vibrator, 8 ... Spacer, 10 ... Supply pipe

Claims (2)

An ultrasonic vibration device including a vibrator;
Two diaphragms connected to a single ultrasonic vibrator, and
The two diaphragms are configured to vibrate with each other in conjunction with the vibration of the vibrator, and are arranged with a predetermined minute gap facing each other,
A liquid supply means for supplying a liquid to the micro gap;
The two diaphragms arranged in a face-to-face manner have different thicknesses, materials, and / or diameters when the diaphragm is a disc. The liquid supply means includes a supply pipe for supplying a liquid,
The feed tube is atomizing device according to claim 1, wherein the disposed nodal position of vibration of the diaphragm is open toward the minute gap.