JPS6244987B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an atomization device for atomizing various liquids such as liquid fuels such as kerosene and diesel oil, water, and chemical solutions. This invention relates to a so-called ultrasonic atomization device that utilizes ultrasonic vibrations of a child.

Conventionally, various types of ultrasonic atomization devices have been proposed and their practical application has been studied.

The first type of ultrasonic atomization device is the one that has been studied for the longest time, in which a piezoelectric vibrator or the like is attached to a horn-type ultrasonic vibrator, and the vibration amplitude is amplified by the vibrator. The liquid is supplied to the tip of the horn using a pump or the like to atomize it.

The second 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 to concentrate ultrasonic energy near the liquid surface to form a liquid column. This is a liquid column type ultrasonic atomizer that atomizes using capillary waves generated near the liquid surface. Furthermore, as the third ultrasonic atomization device,
There is a configuration shown in FIG. This has an orifice 2 at one end of the liquid chamber 1, and a piezoelectric vibrator 3 at the other end.
The pressure increase in the liquid chamber 1 caused by the vibration of the piezoelectric vibrator 3 is transmitted to the orifice 2, and the liquid droplets 4 are ejected from the orifice 2 to atomize them. This is widely used for atomizing ink.

However, these conventional atomizing devices have had various disadvantages as described below.

The first ultrasonic atomization device requires high machining accuracy and complicated fixing conditions for the horn vibrator for amplitude expansion, and requires a pump, etc., making the entire device large and expensive. It has to be priced, and furthermore, the electricity required to obtain an atomization amount of about 20c.c./min, for example, is
Although it was about 10 Watts, sufficient atomization ability could not be obtained.

In addition, the second ultrasonic atomization device does not require a pump or the like and has excellent atomization ability, but the drive frequency of the piezoelectric vibrator is a high frequency of 1 to 2MHz, and moreover, it is 20c.c./ The electric power required to obtain the amount of atomization for about 50 minutes was large, about 50 watts.

For this reason, the drive circuit is expensive, and since ultrasonic energy is directly emitted into the liquid and used directly, atomization performance fluctuates significantly depending on the physical properties of the liquid and the height of the liquid level, and compensation for this is extremely troublesome and difficult. It was something to master. An even more serious drawback is that there is a high possibility of radio interference occurring due to its high frequency and large power, which has been a major obstacle to widespread practical use.

Although the third ultrasonic atomization device has a simple and compact configuration and low power consumption, the pressure increase in the liquid chamber 1 caused by the vibration of the piezoelectric vibrator 3 is
Since the structure is such that the liquid is transmitted to the orifice 2 through the liquid, it can be used with general liquids containing a large amount of dissolved air,
Bubbles were generated due to cavitation that attempts to atomize a liquid with a low vapor pressure, making it impossible to maintain a satisfactory atomization operation. Therefore, it could only be used for very special purposes such as atomization of ink liquid from which dissolved air has been removed.

The present invention aims to provide an ultrasonic atomization device that eliminates the above-mentioned conventional drawbacks.

The first purpose is to have a simple and compact configuration.
It is also an object of the present invention to provide an atomization device that has extremely low power consumption and is therefore inexpensive.

The second object is to provide an atomization device that can stably atomize even general liquids that contain a large amount of dissolved air.

A third object is to provide an atomizing device that can freely control the particle size and particle size distribution of atomized particles and can therefore be applied to a wide range of purposes.

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

That is, it includes a pressurizing chamber filled with liquid, a plurality of nozzles provided facing the pressurizing chamber, and an electric vibrator for vibrating the nozzles. The nozzle is configured to have a difference in width, and atomized particles having an arbitrary particle size distribution are injected from the nozzle.

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 5, and is adapted to give an operation command to a control section 7. When the control unit 7 receives the operation start command, it starts the blower fan motor 8, and the blower fan 9 and the pressure fan 10 rotate. Therefore, combustion air flows from the suction port 11 to the orifice 1.
2 to the swirler 13, from the swirler 13 to the atomization chamber 14 and the combustion chamber 15 as shown by the arrow in the figure, and then exhausted from the exhaust stack 16. At this time, the negative force generating section 17 on the downstream side of the orifice 12
For example, a negative pressure of about −20 mmH ₂ O is generated.

On the other hand, kerosene is sent from the tank 18 to the leveler 20 through a pipe 19, and the liquid level A in the leveler 20 is controlled 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 23.
and is connected to the inlet side 25 of the pressure fan 10 by a pipe 24. When the operation is stopped,
The liquid level of kerosene in the pipe 23 passes through the filter 26 and reaches the position B in the figure. However, when the operation is started, the pressure fan 10 and the blower fan 9 rotate, and as described above, the negative pressure generating section 17
A negative pressure of -20mmH ₂ O is generated at the pipe 2.
Since the negative pressure generating section 17 and the outlet side 27 of the pressure fan 10 are connected at 6, the pressure on the inlet side 25 is determined by the pressure difference generated by the pressure fan 10 (for example,
-40mmH ₂ O) and the negative pressure of the negative pressure generating part 17 (-20mm
H ₂ O), for example, -60mmH ₂ O
This results in negative pressure. Therefore, the liquid level B in the pipe 23
rises, fills the inside of the atomizer 21 with kerosene, rises further, and becomes balanced at the position of the liquid level C in the pipe 24.

In this way, the atomizer 21 is filled with kerosene during pre-purging by the blower fan 9, and preparation for the atomization operation is completed.

Next, the control unit 7 energizes the atomizer 21 and activates the igniter 28 from the built-in oscillation circuit, so that the atomizer 21 atomizes the atomized particles 29 into the atomization chamber 14 .

As shown in the figure, a part 30 of the atomized particles 29 has a particle size that is extremely small compared to the other atomized particles in the center. This is to ensure good ignition by the igniter 28, and if all the atomized particles are made too small, it will not be possible to obtain a sufficient amount of atomization and a sufficient injection distance will not be obtained. In this way, only some of the atomized particles 30, that is, only the atomized particles located on the outer periphery and close to the tip of the igniter 28, have extremely small particle diameters.

Therefore, ignition by the igniter 28 is performed extremely smoothly, and the flame 31 is formed and burned.
The state 1 is detected by the sensor 32.

Stabilization of the combustion state and control of the amount of combustion are performed by the control unit 7 based on signals from the sensor 32, as will be described later, so that stable and necessary combustion can be achieved. Note that 33 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.

In the atomizer 21, a base body 35 having a pressurized chamber 34 with a depth of 2 to 5 mm and a diameter of 8 to 12 mm is fixed to a case 36 with screws 37, and the case 36 is fixed to the atomization chamber wall surface 22 with screws 38 and 39. It is installed as follows.

The pressurizing chamber 34 is provided with a supply port 40 and an exhaust port 42, which are connected to pipes 23 and 24, respectively. Also, the thickness is 30 μm to 100 μm with multiple nozzles 43 having a diameter of 30 μm to 100 μm provided in the center.
A nozzle plate 44 is configured to face this heating chamber 34. The nozzle plate 44 has its outer periphery bonded to the base body 35, and has a diameter of 8 to 12 mm and a thickness.
A ring-shaped piezoelectric ceramic 45 of 0.5 to 1 mm is bonded. An opening 46 is provided in the center of the piezoelectric ceramic 45, and the nozzle plate 44 facing there
A flat portion 47 and a spherical protrusion 48 are provided.
The nozzle 43 is arranged so as to be distributed between a protruding part 48 and a flat part 47, and as shown in the figure, the atomized particles 29 of an appropriate particle size, that is, a particle size that can realize good combustion, and a good combustion. The atomized particles 30 have a smaller particle size that can be ignited.

The piezoelectric ceramic 45 is supplied with an alternating current voltage as shown in FIG. The voltage control shown in FIG. 4 a, b, or c can be used to stabilize the combustion state by adjusting the atomization amount using the signal from the sensor 32, or to adjust the combustion amount to the required optimum value. This shows a control method when controlling to a=T, as shown in FIG.
By controlling _Io / _T2 , it is possible to obtain any atomization amount _qo .

FIG. 6a is a diagram illustrating the atomizing operation of the atomizer 21 in FIG. 3, and the same reference numerals as in FIG. 3 are equivalents. The piezoelectric ceramic 45 undergoes expansion and contraction depending on the positive and negative polarity of the AC voltage waveforms shown in FIGS. 4a to 4c, and as a result, the nozzle plate 44 is excited to flexural vibration as shown. Flat part 47 of nozzle plate 44 facing opening 46
As shown in FIG. 6b, the vibration amplitude distribution of the protrusion 48 is significantly larger than that of other parts.
shows. Since the protrusion 48 vibrates like a kind of rigid body, the amplitude of this portion is almost uniform throughout. Therefore, in order to obtain uniform droplets, the nozzle 43 may be provided only on this projection 48.

However, by configuring the nozzle to be provided also on the flat part 47 as shown in FIG. 6a, the nozzle is located in a place where the vibration amplitude is small, as is clear from the amplitude distribution in FIG. 6b. It happens.

The vibration amplitude δ and the atomized particle diameter d have a nearly proportional relationship as shown in FIG. 7, and therefore the particle size distribution of the atomized particles as shown in FIG. 6a can be obtained.
Compared to the atomized particles 29 in the center, the atomized particles 30 on the outer periphery
It is possible to improve the ignitability by reducing only the particle size of the particles.

FIG. 8a is a sectional view showing another embodiment of the present invention, and the same reference numerals as in FIG. 6a are equivalent.

In this case, there is no protrusion in the central portion 47 of the nozzle plate 44, and as is clear from the amplitude distribution map b of the nozzle plate central portion 47, the vibration amplitude of each nozzle is approximately equal to the large amplitude portion in the center. The size of the atomized particles decreases from the center to the outer periphery, and the atomized particle size corresponds to this, so that a nearly uniform group of particles is sprayed in the center and atomized particles with smaller diameters are sprayed toward the outside. It's getting old.

As in the embodiment shown in FIG. 6a or FIG. 8a, the nozzle 4 is moved by vibration of the piezoelectric ceramic 45.
3 is excited and the atomized particles 29 are atomized, and the amount of kerosene in the pressurized chamber 34 that is reduced due to the atomization is sucked up through the pipe 23 and replenished. This is because the surface tension of the kerosene generated in the nozzle 43 causes air to flow from the nozzle 43 into the pressurized chamber 34.
This is because it prevents it from flowing into the country. Therefore, this atomization device can atomize kerosene and suck it up from the leveler 20 simply by driving the piezoelectric ceramic 45 and vibrating the nozzle 43, making it a self-sufficient atomization device. can operate as.

According to experiments, the power consumption of the piezoelectric ceramic 45 required to atomize kerosene at about 20 c.c./min using the atomization device shown in Fig. 3 is about 0.1 watt, making it an extremely energy-saving atomization method. It is possible to realize the device.

Another feature is that even if the liquid to be atomized (that is, kerosene in this embodiment) contains a large amount of dissolved air, it can be atomized extremely stably. This is because the configuration is such that droplets are sprayed from the nozzle when the nozzle 43 is vibrated. That is, the vibration amplitude is the largest near the nozzle 43, and therefore, the maximum point of pressure change in the pressurizing chamber 34 is only near the nozzle 43, and even if cavitation bubbles are generated and try to grow at this point, This is because the liquid is sprayed from the nozzle 43 before it becomes bubbles. Furthermore, even if bubbles form, the area near the nozzle in the pressurizing chamber 34 that affects the atomizing operation is a very narrow area, so the bubbles will immediately jump out of this area and have no effect on the atomizing operation. Since the particles move to areas where they are not affected and are discharged from the exhaust port 42, there is virtually no adverse effect on the atomization operation.

Therefore, even a liquid containing a large amount of dissolved air, such as kerosene, can be atomized extremely stably.

As described above, according to the present invention, a plurality of nozzles are arranged to face a pressurized chamber filled with liquid, and the nozzles are vibrated by an electric vibrator, and the vibration of the plurality of nozzles is Because it has a configuration with different amplitudes, the configuration is extremely simple, compact, and consumes low power.As a result, it is extremely low-priced, and even liquids containing large amounts of dissolved air can be atomized extremely stably. It is possible to realize an atomization device that can do the following. In particular, by providing a configuration in which the vibration amplitudes of a plurality of nozzles are differentiated, it is possible to provide an atomization device that can extremely easily and stably obtain any desired particle size and particle size distribution. Therefore, it is possible to realize a highly versatile atomizing device for atomizing various common liquids for various purposes with an extremely simple configuration, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a conventional atomization device.
Fig. 2 is a cross-sectional view showing the configuration of a hot air fan to which an embodiment of the present invention is applied, Fig. 3 is a cross-sectional view showing the configuration of an atomizer according to an embodiment of the present invention, and Figs. 4 a and b. and c are piezoelectric ceramic drive voltage waveform diagrams, Figure 5 is a characteristic diagram explaining atomization ability control, Figure 6 a,
b is a configuration diagram for explaining the operation of the atomization device in Fig. 3 and a vibration amplitude distribution diagram, Fig. 7 is a characteristic diagram showing the correlation between the vibration amplitude δ of the nozzle and the particle diameter d of the atomized particles, and Fig. FIGS. 8a and 8b are a configuration diagram and a vibration amplitude distribution diagram showing an explanation of the operation of an atomizing device showing another embodiment of the present invention, respectively. 34... Pressure chamber, 43... Nozzle, 44... Nozzle plate, 45... Piezoelectric ceramic (electrical vibrator), 47... Flat portion, 48... Projection.

Claims (1)

[Scope of Claims] 1. A pressurized chamber filled with liquid, a plurality of nozzles provided facing the pressurized chamber, and an electric vibrator that vibrates the nozzles, the plurality of nozzles Atomization device with different vibration amplitudes. 2. The atomization device according to claim 1, wherein the nozzle is provided on a nozzle plate, and the nozzle plate is deflected and vibrated by the electric vibrator. 3. The atomization device according to claim 2, wherein a nozzle plate is provided with a protrusion and a flat part, and the nozzle is provided on the protrusion and the flat part.