JPS5812063B2 - Ultrasonic atomizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic atomizer that vibrates a vibration amplifying horn by the vibration of an ultrasonic vibrator and atomizes liquid supplied to the atomizing surface of the horn. This invention relates to a vibration countermeasure structure for a liquid supply passage formed through the horn.

The most common ultrasonic atomization device conventionally used will be explained based on FIG. 6.

Reference numeral 1 denotes an ultrasonic vibrator with a vibrating element 2 inserted therein, and a vibration amplifying horn 3 is connected to one end of the ultrasonic vibrator.

A liquid supply passage 4 is bored inside the vibration magnifying horn 3. One end of the liquid supply passage 4 communicates with a part of the atomization surface 5 through an opening 6, and the other end communicates with the node position of the vibration magnifying horn ( It is connected to a conduit 9 via a vibration isolator 8 at a vibration zero position 7.

The other end of conduit 9 communicates with a liquid tank (not shown) via a flow regulator (not shown).

10 and 11 are corners inside the liquid supply passage 4, respectively.

In the ultrasonic atomization device as described above, vibration is started,
When the liquid is sent, atomized particles 12 are released from the atomizing surface 5 as shown in FIG. 7, but at the same time, a large number of fine bubbles 13 are generated from the inner peripheral surface and corners 10 and 11 of the liquid supply passage 4. However, fine bubbles 14 are also formed due to cavitation caused by liquid vibration.
occurs.

These fine bubbles 13 and 14 accumulate at positions where the forces of the liquid flow rate and the vibration are balanced, forming a bubble group 15.

As time passes, the fine bubbles 13 within the bubble group 15 combine with each other, eventually forming large bubbles 16 as shown in FIG. The force applied to the atomizing surface 5 becomes stronger, and the air bubbles 16 are swept away toward the opening 6. When the air bubbles 16 reach the opening 6, as shown in FIG. Since the atomized particles 12 are stopped due to this, breaks occur in the atomized particles 12.

As described above, the most common ultrasonic atomization device that has been used so far has had a major problem in that continuous atomization cannot be performed due to the occurrence of interruptions.

Therefore, if this ultrasonic atomizer is incorporated into a combustion device, it may cause a misfire due to interruptions in atomization, making it unusable.If it is incorporated into a painting device, it may cause uneven coating, etc. This becomes a big problem.

The present invention aims to provide an ultrasonic atomization device that does not cause interruptions in atomization and can exhibit stable performance.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

In addition, in FIGS. 1 to 5, the same symbols as in FIGS. 6 to 9 indicate the same members.

In the figure, reference numeral 1 denotes an ultrasonic vibrator with a vibrating element 2 inserted therein, and a vibration amplifying horn 3 is connected to one end of the ultrasonic vibrator.

A liquid supply passage 4 whose inner peripheral surface is covered with a vibration damping material 17 is formed through the inside of the vibration magnifying horn 3, and one end passes through a part of the atomization surface 5 through an opening 6, and the other end passes through a part of the atomization surface 5 through an opening 6. communicates with the conduit 9 and is connected to a fuel tank (not shown) via a solenoid valve 19 and a flow rate regulator 20.

Reference numeral 21 denotes an inner cylinder, which is arranged so as to concentrically surround the vibration amplifying horn 3.

The circumference of this inner cylinder 21 is filled with primary combustion air and an ultrasonic vibrator 1.
A vibration amplifying horn support 24 is fixed to one end via a vibration damping device 23, and the vibration amplifying horn 3 has one or more air intake ports 22 to take in air for cooling. It is fixed to the fixture 24.

A radiant air agitator 25 is attached to the other end of the inner cylinder 21, and a secondary air passage 27 is formed by the inner cylinder 21 and an outer cylinder 26 disposed concentrically with the inner cylinder 21. ing.

Reference numeral 28 denotes a front end face plate of the radial air atomizer 25, which is located almost on the same plane as the vibration atomizing surface 5.
The combustion chamber 30 is equipped with a combustion tube 29 having a diameter larger than the inner diameter of the combustion chamber 30.
It forms a compartment.

A partition plate 31 having a hole smaller than the inner diameter of the radial air disruptor 25 and larger than the diameter of the front part of the vibration amplifying horn 3 is provided on the rear end surface of the radial air disruptor 25 to separate the vibration amplifying horn 3 from the partition plate 31 . An annular gap 32 is formed therebetween.

Reference numeral 33 denotes a blower, which is connected to the outer cylinder 26 via a blower port 34 that can send a tangential air flow into the secondary air passage 27.

Reference numeral 35 denotes a back cover, which is partially equipped with a flame detector 36.

37 is an ultrasonic oscillator, and 38 is a flange for attaching the combustion device.

The vibration damping material 17 described above has elasticity, oil resistance, and vibration resistance so as not to cause cracks or cracks due to vibration.
It is preferable to use a material having heat resistance of 100'C or more, and in addition to rubber materials such as nitrile rubber, resin materials such as fluororesin can be used.

Further, the material of the horn 3 to which this vibration damping material 17 is attached may be stainless steel, duralumin, aluminum,
Examples include nickel, nickel-chromium steel, titanium alloy, and the like.

Next, the operation of the ultrasonic atomizer shown in FIG. 1 will be explained.

When the vibration is started and the liquid is sent, the atomized particles 12 are released from the atomizing surface 5 as shown in FIG. is attenuated by

Therefore, from the inner peripheral surface and corner portions io and ii of the liquid supply passage 4,
Generation of fine bubbles 13 due to cavitation is eliminated.

In addition, since the vibration of the conduit 9 is also prevented by the vibration isolating material 8, the liquid in the liquid supply passage 4 and the conduit 9 will not vibrate as a liquid column, so the fine bubbles 13 generated by cavitation due to the vibration of the liquid column will not occur. will also disappear.

Since the generation of fine bubbles 13 is eliminated, ζ1, large bubbles 16
There will be no formation of , and no interruptions in atomization will occur.

Furthermore, in conventional ultrasonic atomizers, cavitation noise caused by cavitation that occurs in the liquid supply passage 4, particularly near the opening 6, is very audible and can cause discomfort, especially when placed indoors as an ultrasonic humidifier. However, this noise can also be eliminated by preventing cavitation.

Next, the structure of the vibration damping material 17 itself and its installation will be described.

As this cushioning material 17, a highly elastic material such as rubber can be used, but the diameter of the liquid supply passage 4 is about 1.5 mm to 4 mm in a normal ultrasonic atomization device, so it is possible to use a highly elastic material such as rubber. It is very difficult to arrange a rubber material or the like on the inner peripheral surface of the liquid supply passage 4 which has a small diameter, is elongated, and is subject to vibration.

Therefore, as shown in FIG. 2, a thermally expandable fluororesin tube 18 is inserted into the liquid supply passage 18 as shown in FIG.
Insert inside.

When the tube 18 made of fluororesin is heated and expanded, it contracts in the longitudinal direction, so the length is adjusted to account for the shrinkage.

When heated, the inner circumferential surface of the liquid supply passage 4 can be easily coated, as shown in FIG.

According to the method described above, the inner circumferential surface of the liquid supply passage 4 can be easily coated with the vibration damping material 17, and therefore, an ultrasonic atomization device with no interruption in atomization can be easily obtained.

The ultrasonic atomization device as described above can constitute a combustion device as shown in FIG.

In this combustion device, the air flow sent into the secondary air passage 27 from the blower 33 through the air outlet 34 flows toward the radial air disturbance body 25 while most of the air flows inside the secondary air passage 2T. A part of the air passes through the intake port 22 and flows into the inner cylinder 21 and is further divided into primary combustion air and cooling air for the ultrasonic vibrator 1. The ultrasonic vibrator cooling air is passed through the vibration amplifying horn support 24. The primary combustion air cools the ultrasonic vibrator 1 through the gap formed by the partition plate 31 and the vibration amplifying horn 3, and is ejected into the combustion chamber 30 through the annular gap 32 formed by the partition plate 31 and the vibration amplifying horn 3.

The air flowing while swirling in the secondary air passage 27 is made uniform between the paths along the way, and is further given a strong swirl by the radial air disruptor 25 and is ejected into the combustion chamber 30 as main combustion air. .

- 10,000, the fuel reaches the atomization surface 5 from the fuel tank (not shown) through the flow rate regulator 20 and the solenoid valve 19, through the conduit 9 and the liquid supply passage 4, and then reaches the atomization surface 5 through the ultrasonic oscillator 37 and the ultrasonic vibrator 1.
The vibrations generated are amplified by the vibration amplifying horn 3, thereby atomizing the fuel on the atomization surface 5.

Atomized fuel atomization particles have many problems that make them unsuitable for combustion, such as the particle speed being slow and the atomization pattern not being consistent, unlike the particles atomized by normal pressure spraying or air atomization. .

Therefore, the atomization pattern is corrected by the primary combustion air, the fuel and the fuel air are mixed by the strong swirl of the primary combustion air, and ignited and burned by an ignition device (not shown).

However, since the atomized particle group generated by ultrasonic vibration contains many large atomized particles, especially 10,000 particles,
In a flame with a combustion rate of Km/h or less, a large amount of unburnt particles are scattered, and a large amount of carbon monoxide is generated, resulting in a significant reduction in combustion heat output.

Therefore, the combustion flame is wrapped in the combustion tube 29, and the unburned particles are vaporized in the combustion tube 29, thereby achieving good combustion.

Here, if the amount of primary combustion air is too large, misfires due to flame blow-off may easily occur, and mixing of fuel and combustion air may deteriorate.

It may cause soot formation.

On the other hand, if the amount is too low, the flame may cling to the tip of the vibration magnifying horn 3, causing burnout, causing instability of the atomization pattern, causing flame fluctuations, and carbon buildup on the inner wall of the combustion tube 29. It causes.

Therefore, it is possible to stably take in the minimum necessary primary combustion air from the intake port 22 of the inner cylinder 21, eliminate the need to extremely narrow the annular gap 32, and send sufficient light to the flame detector 36. In addition, since the vibration amplifying horn 3 emits ultrasonic vibrations, it is difficult to fix it, and it requires an extremely difficult technique to align the centers.
Since it is wide and removable, assembly work is easy.

Further, the amount of combustion can be easily changed by the flow rate adjustment device 20, and a predetermined amount can be atomized on the atomization surface 5, but the atomization pattern also changes depending on the change in the flow rate of the fuel.

The position of the atomization surface 5 is the front end face plate 28 of the radial air agitator 25.
When the combustion atomized particles are moved further toward the partition plate 31 side, the combustion atomized particles hit the radiant air disruptor 25, and the fuel flows into the secondary air passage 27. Conversely, the atomization surface 5 is closer to the combustion chamber than the front end face plate 28. If the horn 3 goes too far inside the horn 3, there is a danger that the horn 3 will be burnt out due to the flame clinging.

Therefore, by arranging the atomization surface 5 at a position substantially on the same plane as the front end face plate 15, safe and highly stable combustion can always be maintained even if the combustion amount changes.

Note that the position of the atomization surface 5 and the strength of the swirling of the combustion air flow are set to have an appropriate flame-holding ability, so if there is a break in the supply of atomized fuel, the combustion device may misfire. However, by incorporating the above-mentioned ultrasonic atomizer, the atomized fuel will not be cut off, so misfires will not occur.

As described above, according to the ultrasonic atomization device of the present invention, liquid can be smoothly atomized without interruption and with uniform particle diameter.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of essential parts of an ultrasonic atomization device according to an embodiment of the present invention, FIG. The figure is a sectional view showing the state when the buffer material is installed in the liquid supply passage and the state after the same installation, Figure 5 is a partial cross-sectional side view of a combustion device equipped with the same device, and Figure 6 is 1 is a partially sectional side view showing a conventional ultrasonic atomization device of this type, and FIGS. 7, 8, and 9 are partially sectional side views showing the operating state of the same device. DESCRIPTION OF SYMBOLS 1... Ultrasonic vibrator, 3... Vibration magnification horn, 4... Liquid supply passage, 5... Atomization surface, 17...・・Vibration buffer material, 18・・・・・・
tube.

Claims (1)

[Scope of Claims] 1. An ultrasonic vibrator having an ultrasonic vibrator and a vibration amplifying horn fixed thereto, and having a liquid supply passage passing through the horn so as to communicate with the atomization surface of the vibration amplifying horn. . An ultrasonic atomizer, characterized in that a vibration damping material is provided on the inner peripheral surface of the liquid supply passage. 2. The ultrasonic atomization device according to claim 1, wherein the vibration damping material is a fluororesin that expands upon heating and comes into close contact with the liquid supply passage.