JPS58216753A - Atomizer - Google Patents

Abstract

PURPOSE:To make the effective use of the oscillation energy for the purpose of atomization operation, by providing a projection part to a nozzle plate to be exicited by an electrical oscillator, and providing nozzles to the projection part. CONSTITUTION:A spherical projection part 41 is provided at the center on one side of a pressurization chamber 33, and a nozzle plate 43 of 30-100mum thickness provided with plural nozzles 42 of 30-100mum diameter is mounted to the part 41. An annular piezoelectric oscillator 45 having an opening 44 at the center is mounted to the plate 43, and as the oscillator 45 generates expanding and contracting strains according to the positive and negative waveforms of the AC voltage, deflective oscillations are excited in the plate 44. Since the part 41 operates as a rigid body, the oscillation amplitude delta in the projection part is roughly constant and the amplitude in said part alone is considerably larger than the oscillation in the other part. Therefore, uniformly atomized particles are obtained by providing plural pieces of the nozzles 42 to the part 41.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an atomizer for atomizing a liquid such as a liquid, and more specifically to a so-called ultrasonic atomizer that utilizes ultrasonic vibrations such as a piezoelectric vibrator.

Conventionally, various types of ultrasonic atomization devices have been proposed.

The most typical first ultrasonic atomizer is a bone type ultrasonic atomizer. This involves attaching a piezoelectric vibrator to the horn vibrator, amplifying its vibration amplitude with the horn, and
Liquid is atomized by supplying liquid with a pump or the like to the maximum amplitude surface at the tip of the horn.

The second type of ultrasonic atomization device is one that has been put to practical use in humidifiers, etc., and is equipped with a piezoelectric vibrator at the bottom of the liquid tank, and irradiates and concentrates ultrasonic waves near the liquid surface to form a liquid column. Atomization is performed using capillary waves near the surface.

Furthermore, as a third ultrasonic atomization device, there is one having a configuration as shown in FIG. In recent years, this atomization device has been equipped with an ink atomization refill 2 for recording devices such as facsimile IJ,
A piezoelectric vibrator 3 is provided at the other end, and the pressure increase in the liquid chamber 1 due to the vibration of the piezoelectric vibrator 3 is transmitted to the orifice 2.
Droplets 4 are ejected from an orifice 2 and atomized.

However, these conventional atomizing devices have the following drawbacks.

The first ultrasonic atomization device requires high machining accuracy of the amplitude amplification horn and complicated installation conditions, and also requires a pump, which makes the entire device larger and more expensive. Although the power required for atomization is as large as about 10 watts for an atomization amount of about 208C/min, it is difficult to The so-called atomization performance was not sufficient.

In addition, the second atomization device is characterized in that it can obtain atomized particles with a significantly small particle size and does not require a pump, but it uses an atomization method using ultrasonic energy directly irradiated into the liquid. Therefore, variations in atomization characteristics due to the physical properties of the liquid and the height of the liquid level are extremely significant, and compensation for this is extremely troublesome and extremely difficult. Furthermore, in order to obtain an atomization amount of 20 cc/min at a high frequency of 1 to 2 MHz, it is necessary to
It requires a large amount of power, about 0 watts, and therefore requires an expensive drive circuit, and has the disadvantage of being susceptible to radio wave interference.

Furthermore, the third atomizing device has a simple and compact configuration, and has the characteristics of extremely low power consumption. Since the structure is such that a pressure increase is transmitted to the orifice 2, bubbles are generated due to cavitation when using a general liquid containing a large amount of dissolved air, making it impossible to maintain a stable atomization operation. Therefore, only liquids from which dissolved air has been removed can be stably atomized, and can only be used for special purposes.

The present invention provides an atomizing device that eliminates the above-mentioned conventional drawbacks.

The first objective is to provide an atomizing device that is simple in construction, compact, and inexpensive.

The second object is to provide a highly versatile atomization device that can stably atomize even a general liquid containing a large amount of dissolved air.

A third object is to provide an atomization device that consumes extremely low power, has excellent atomization performance, and is capable of generating a large amount of atomized particles of uniform and fine particle size.

In order to achieve the above object, the present invention has the configuration described below.

That is, the nozzle plate includes a pressurizing chamber L filled with liquid, a nozzle plate provided with a plurality of nozzles facing the pressurizing chamber, and an electric vibrator that excites the bending vibrations of the nozzles and the plate. The nozzle is provided with a protrusion, and the nozzle is provided on the protrusion, and the bending vibration of the nozzle plate excited by the electric vibrator excites the plurality of nozzles with approximately equal amplitude, thereby producing a uniform vibration. Atomized particles of small particle size are injected from the nozzle and atomized.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing the configuration of a hot air fan to which an atomizing device according to an embodiment of the present invention is applied.

In FIG. 2, an operating section 6 is provided on the top surface of the warm air fan case 6, and is configured to give an operation command to a control section 7. When the control unit 7 receives an operation start command, it starts the blower fan motor 8 and starts the blower fan 9 and the pressure fan 1.
0 rotates. As a result, combustion air is sent from the suction port 11 to the swirler 13 through the orifice 12, and the swirler 13
As shown by the arrow in the figure, the atomization chamber 14. It is supplied to the combustion chamber 16. Then, the air is exhausted from the exhaust pipe 16. For example, the negative pressure generating section 17 downstream of the orifice 12 has a pressure of -20 mm.
A negative pressure of H2O is generated.

Kerosene, which is a fuel, is sent from the tank 18 through a pipe 19 to a leveler 20, and the leveler 20 controls the liquid level A to be constant.

The atomizer 21 is attached to the wall surface 22 of the atomization chamber 14, and is connected to the leveler 20 by a pipe 24 having a filter 23 at the tip.
The inlet side 25 of the pressure fan is communicated with the pipe 26, respectively.

When the operation is stopped, the liquid level inside the vibrator 24 is at position B in the figure, but when the operation is started, the pressure fan 10° and the blower fan 9
Due to the rotation of the pressure fan 10, the inlet side 25 and the outlet side 2
The liquid level B rises by -F due to the negative pressure car 6o Dragon H20, which is the sum of the pressure difference between
The inside of the atomizer 21 is filled with kerosene, and it further rises to the pipe 2.
6 and the liquid level C is in balance. In this way, during pre-purging by the blower fan 9, the atomizer 2
1 is filled with kerosene and preparations for atomization operation are completed.

Next, the control unit 7 energizes the built-in atomizer drive circuit and starts the igniter 28, and the atomizer 21 is removed from the atomization chamber 14.
Atomized particles 29 are atomized. The atomized particles 29 are ignited by the igniter 28 and burned to form a flame 3o.

The combustion state of the flame 30 is detected by the sensor 3'I, and the amount of atomization of the igniter 28 and the atomizer 21 is controlled by the control unit 7 based on this signal. Note that 32 is a convection fan.

Next, the atomizer 21 will be explained in more detail.

FIG. 3 is a sectional view of the atomizer 21, and the same symbols as in FIG. 2 are equivalent.

The atomizer 21 includes a case 35 and a body 34 having a pressure chamber 33 with a depth of 2 to 5 mm and a diameter of 8 to 12 mm inside.
and fix the case 36 to the wall surface 22 with screws 37° and 38.
It is fixedly attached to the

The pressurized chamber 33 has a supply port 39. Exhaust ports 4o are provided vertically facing each other and communicate with pipes 24 and 26, respectively. One surface of the pressurizing chamber 33 is provided with a spherical protrusion 41 in the center, and a nozzle plate 43 with a thickness of 30 μm to 10 μm and provided with a plurality of nozzles 42 with a diameter of 30 μm to 100 μm is attached to this protrusion 41. . This nozzle plate 43 has an opening 44 in the center, has a diameter of 8 to 12 mm, and has a thickness.

, 5 to 2 ring-shaped piezoelectric vibration elements 46 are attached, and the flat part 46 around the protrusion 41 and the protrusion 41 are configured to face the opening 44.

The piezoelectric vibrator 45 is supplied with an AC voltage as shown in FIG. Stretching distortion occurs depending on the polarity. When a positive half-cycle voltage is applied, the piezoelectric vibrator 46 contracts in the diametrical direction, and as a result, the nozzle plate 43 is deflected in the direction of the pressurizing chamber 33, and the nozzle 4
2 is also displaced in the same direction, and a minute droplet 29 is ejected from the nozzle 42. - When the force is in the negative half cycle, the piezoelectric vibrator 46
expands in the radial direction, causing the nozzle plate 43 to deflect in the opposite direction to that described above. At this time, the air inflow from the nozzle 42 is blocked by the surface tension of the kerosene generated therein, and as a result, a pressure drop occurs in the pressurizing chamber 33 corresponding to the increased volume. Therefore, kerosene is sucked up from the vibrator 24, and it functions as a self-sufficient pump.

In this way, the AC t applied to the piezoelectric vibrator 45
Pressure (7) Frequency (e.g. 30KH2 ~ 1oOKH2)
The liquid droplets 29 are ejected according to the amount, and the corresponding amount of kerosene is self-sufficient.

The atomization amount can be adjusted very easily and finely by performing intermittent control as shown in FIG. 6th
The figure shows this situation and shows T1 (operating time) and T
By controlling the ratio α of 2 (repetition time), it is possible to adjust the atomization amount history with extremely excellent linearity.

6a and 6b explain the operation of the atomizing device shown in FIG. 3 in more detail, and the same reference numerals as in FIG. 3 correspond to the same parts.

FIG. 6a shows the nozzle plate 43. The vibration state of the piezoelectric vibrator 46 and the scattering state of the atomized particles 2e are shown, and the figure shows the distribution of the vibration amplitude δ at this time. As is clear from the figure, the vibration amplitude δ of the protrusion 410 portion is approximately constant, and the amplitude of only this portion is significantly larger than that of the other portions. This is due to the provision of the spherical protrusion 41, which causes the protrusion 41 to act as a rigid body; in other words, a disk having a rigid body at the center of the flat portion 46 is flexibly vibrating. . By providing a plurality of nozzles 42 on the protrusion 41 that can be treated as a substantially rigid body, the vibration amplitude δ of the plurality of nozzles can be reduced.
can be made almost uniform. The relationship between the vibration amplitude δ of the nozzle 42 and the atomized particle diameter d is approximately proportional as shown in FIG.
This shows that if the vibration amplitude of No. 2 is constant, the diameter d of atomized particles injected from each nozzle can be made uniform.

FIGS. 8a and 8b show the vibration state and atomization state, and the vibration amplitude distribution δ of each part when the nozzle plate 43 is not provided with the protrusion 41 that can be considered as a rigid body as in this embodiment,
In No. 8 Na, the same reference numerals as in FIG. 6 a correspond to the same parts. As is clear from comparing FIGS. 8a and 8b with FIGS. 6a and 6b, when there is no protrusion 41 that can be considered as a rigid body, the vibration amplitude δ of each of the plurality of nozzles 42 is completely different. It will look like Figure 8. Therefore, the atomized particles 29 in FIG.
This results in the generation of atomized particles with extremely non-uniform particle sizes.

In this way, the nozzle plate 43 is provided with a protrusion 41 that can be regarded as a substantially rigid body, a plurality of nozzles 42 are provided on the protrusion 41, and the nozzle plate 43 is deflected and vibrated to produce mist with uniform and minute particle size. It is possible to generate a large amount of particles.

As shown in FIGS. 6a and 6b, the maximum point of pressure change in the pressurizing chamber 33 is near the nozzle 42, and the atomized particles 29 are injected only by an increase in pressure in the very vicinity of the nozzle 42. Therefore, even liquids containing an extremely large amount of dissolved air, such as kerosene, can be stably atomized. This is because, as mentioned above, the maximum pressure change is near the nozzle 42, so the bubbles are injected from the nozzle 42 before they form, and even if they may form, , Pressurized chamber 33 that affects spraying
Since the inner region is a narrow region very close to the nozzle 42, it immediately jumps out from this region and is discharged from the exhaust port 40, so it hardly affects the atomization operation.

9, 10, and 11 are cross-sectional views of an atomizing device showing other embodiments of the present invention, and the symbols in FIGS. 6- and 4' correspond to each other. In FIG. 9, the protrusion 41 is formed into a plateau shape, and a plurality of linear droplet arrays having a uniform particle size can be generated to obtain a large amount of atomization.

In FIG. 10, the protrusion 41 is conical, and a so-called hollow cone atomization pattern can be obtained.
Furthermore, uniform atomized particles can be obtained.

FIG. 11 shows an atomization pattern that is a combination of the atomization patterns shown in FIGS. 9 and 10, in which nozzles 42 are provided at the top and slope of the protrusion 41.

As mentioned above, the atomizing device of the present invention can be implemented in various ways, but as is clear from the principle of its atomizing operation, it is configured to vibrate the nozzle, so the vibration energy of the atomizing operation is reduced. It is possible to obtain an atomization device with extremely high utilization efficiency and extremely low power consumption. According to experiments, the power consumption of the piezoelectric vibrator 46 required to atomize about 20 cc/min of kerosene using the atomizing device of the embodiment shown in FIG. 3 is about 0.1 watt. Often, power consumption of several φ or less is sufficient compared to conventional ultrasonic atomization devices.

As described above, according to the present invention, there is provided a pressurized chamber filled with liquid, a nozzle plate provided with a plurality of nozzles facing the pressurized chamber, and an electric vibration that excites bending vibration in the nozzle plate. Since the nozzle plate is provided with a protrusion, and the nozzle is provided on the protrusion, the structure is extremely simple and compact, and therefore the cost is low. It is possible to provide an extremely versatile atomization device that can perform stable atomization even if the In particular, since a protrusion is provided and a nozzle is installed in this protrusion, it is possible to generate a large amount of atomized particles of uniform and small diameter, and it is possible to exhibit excellent atomization performance, and also to achieve remarkable atomization performance. Low power consumption,
A highly energy-saving atomization device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a conventional atomizing device, FIG. 2 is a sectional view showing the configuration of a hot air fan to which the atomizing device of an embodiment of the present invention is applied, and FIG. 3 is the same atomizing device. 4a and 4b are drive voltage waveform diagrams of the piezoelectric vibrator, and FIG. 6 is a characteristic diagram illustrating the method of controlling the atomization amount t.
, b are a cross-sectional view and a vibration amplitude distribution diagram explaining the vibration state of the atomizer shown in FIG. 3, FIG. 7 is a characteristic diagram explaining the correlation between the vibration amplitude δ and the atomized particle diameter d, and FIG. Figures a and b are a cross-sectional view and a vibration amplitude distribution diagram showing the vibration state of the embodiment of the present invention, respectively, Figure 9 is a cross-sectional view showing another embodiment of the atomization device of the present invention, and Figure 10 is the same and another example. Cross-sectional view showing an example of the 11th
The figure is a sectional view showing still another embodiment. 33... Pressure chamber, 41... Protrusion, 4
2... Nozzle, 43... Nozzle plate, 4
4...Aperture, 46...Electric vibrator (
piezoelectric vibrator), 46... flat part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure χ Figure 7 Figure 8

Claims (1)

[Scope of Claims] (1) A pressurized chamber filled with liquid, a nozzle plate provided with a plurality of nozzles facing the pressurized chamber, and an electrical device that energizes the nozzle plate and excites flexural vibration. An atomizer comprising: a vibrator, a protrusion provided on the nozzle plate, and the nozzle provided on the protrusion. Shun) The electric vibrator is composed of a piezoelectric vibrator with an opening,
The atomization device according to claim 1, wherein a projection portion faces the opening. (3) The atomization device according to claim 2, wherein a flat portion is provided around the protrusion of the nozzle plate facing the opening. (4) The atomization device according to any one of claims 1 to 3, wherein the nozzle plate is provided with a spherical protrusion.