JPS648588B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an atomizing device for atomizing liquid fuels such as kerosene and light oil, water, and liquids such as chemical solutions.
More specifically, the present invention relates to a piezoelectric spray device configured to vibrate liquid filled in a pressurized chamber using an electric vibrator such as a piezoelectric ceramic and spray the liquid from a nozzle.

Conventional configurations and their problems Conventionally, this type of atomization device has been put into practical use mainly as an ink jetting device for inkjet recording devices, but these have a simple structure as is well known. A single droplet train was generated in response to an electrical signal to print characters, etc. Therefore,
It was only capable of ejecting a small amount of specially treated ink, and was not an atomizing device that could be used in the industrial field mentioned above. However, in recent years, a spraying device as shown in FIG. 1 has been proposed. In the figure, a nozzle plate 4 provided with a plurality of nozzles 3 is attached to one end of a body 2 having a pressurizing chamber 1, and a diaphragm 5 and a diaphragm 5 are attached to the other end of the pressurizing chamber 1 having a large cross-sectional area. Piezoelectric ceramics 6 are bonded to each other and attached to the body 2 as shown in the figure. As shown in the figure, a supply pipe 7 and an exhaust pipe 8 are connected to the top and bottom of the pressurizing chamber 1, and are connected to a tank 9 and a suction port 11 of a fan 10, respectively.

When the fan 10 is stopped, the liquid level A in the supply pipe 7 is at the same level as the tank liquid level B, but when the fan 10 is started, negative pressure is generated at its suction port 11. The liquid level A is sucked up by this negative pressure and becomes balanced with the liquid level C in the exhaust pipe 8, so that the inside of the pressurizing chamber 1 is filled with liquid as shown in the figure.

Next, the AC voltage shown in FIG. 2 is supplied to the electrodes (not shown) of the piezoelectric ceramic 6.

When the AC voltage shown in FIG. 2 is supplied between the bonding surface of the piezoelectric ceramic 6 with the diaphragm 5 and the electrodes provided on the surface facing it, the piezoelectric ceramic 6 and the vibration waves 5 will be generated as shown in the figure. Flexural vibrations as shown by the broken line are generated to vibrate the liquid in the pressurizing chamber 1.

The pressure increase in the liquid due to this vibration is amplified and becomes high pressure near the nozzle 3 due to the horn shape of the pressurizing chamber 1, and as a result, micro droplets 12 are ejected from the nozzle 3 as shown in the figure. It was something that would be done.

This type of atomization device has a compact structure and can operate with extremely low power consumption, as well as the ability to easily adjust the amount of atomization by simply controlling the AC voltage. Although it had the following characteristics, it also had the following drawbacks.

Since the pressurized chamber 1 is filled with liquid using the negative pressure generated by the fan 10, the liquid is filled so that this negative pressure -P is balanced with the height h between the liquid levels A and C. The height of surface C is determined. That is, if the density (specific amount) of the liquid is ρ, then P=ρ×
It becomes h and balances out.

Therefore, the negative pressure −P generated by the fan 10
For example, if the liquid is water and an attempt is made to obtain h=50 mm, a negative pressure of -P=-50 mmH ₂ O is required, which requires a fan capable of generating a considerably high pressure. For this reason, the fan 10 has the drawbacks of generating noise and being large in size because it needs to be fast. In addition, the suction height h changes depending on the density ρ of the liquid, and the position of the liquid level A is determined by the height of the liquid level B in the tank 9, so the height of the liquid level C is In extreme cases, the liquid level C may drop to the inside of the pressurizing chamber 1, or conversely rise too much and cause the fan 10 to There was an inconvenience that liquid may flow into the suction port 11 of the device.

In addition, the fan 10 suddenly changes from the state shown in Figure 1.
When the pump is stopped, pressure (positive pressure) due to the liquid in the exhaust pipe 8 is applied to the liquid in the pressurizing chamber 1. In other words, the height from nozzle 3 to liquid level C is
When hh, the internal pressure of the liquid near nozzle 3 Pin
is Pin=ρ×hh.

For this reason, the liquid overflows from the nozzle 3, and the overflowing liquid causes the spraying operation to become unstable.

OBJECTS OF THE INVENTION The present invention provides an atomization device that eliminates such conventional drawbacks.

The first objective is to have a compact structure, to reliably fill the pressurizing chamber with liquid regardless of the height difference between the liquid tank and the pressurizing chamber, or the density of the liquid, and to stably fill the pressurizing chamber with extremely low power. An object of the present invention is to provide an atomization device capable of atomizing.

The second purpose is to provide an atomizer that completely prevents the inconvenience of liquid overflowing from nozzles, exhaust pipes, etc., and that does not stain equipment or cause instability in spray operation. be.

Structure of the Invention In order to achieve the above object, the present invention has the following structure.

That is, a body having a pressurizing chamber, a nozzle facing the pressurizing chamber, an electric vibrator that vibrates the liquid in the pressurizing chamber and sprays it from the nozzle, a tank for storing the liquid, and a liquid transport means. In addition, the pressurizing chamber is provided with a supply port and a discharge port, and both ports are connected to a tank and a liquid transport means, respectively, so that the pressurizing chamber is filled with liquid. Therefore, the liquid transport means transports the liquid from the tank to the supply port, the pressurized chamber, the discharge port, and then to the liquid transport means, so that the pressurized chamber is filled with liquid, and the electrical vibration is generated. The vibration of the child causes it to be sprayed from the nozzle and become atomized.

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

FIG. 3 is a sectional view of an atomizing device showing one embodiment of the present invention.

In FIG. 3, the atomizing section 13 has a cylindrical pressurizing chamber 1 with a diameter of 5 to 15 mm and a depth of about 1 to 5 mm.
4 and a body 15 with a diameter of 30 μm to 100 μm
Equipped with multiple nozzles 16 with a thickness of 30 μm ~
It consists of a nozzle plate 17 of about 100 μm and a disc-shaped piezoelectric vibrator 19 having an opening 18 with an outer diameter of 5 to 15 mm and a thickness of 0.5 to 2 mm, which are glued together as shown in the figure, and screws 20 It is fixed to the mounting plate 21 at.

The pressurizing chamber 14 is provided with a supply port 22 and a discharge port 23, which are connected to a supply pipe 24 and a discharge pipe 25, respectively. The supply port 24 is connected to a tank 26 for storing liquid, while the discharge pipe 25 is connected to a plunger-type electrically driven pump 2 which is a liquid transport means.
7 is connected. Therefore, the liquid is sent from the tank 26 through the supply pipe 24 and the supply port 22 to the pressurizing chamber 14, and further flows through the discharge port 23 and the discharge pipe 25 to the pump 27. , and is sucked up from the tank 26 by the operation of the transport pump 27 and transported. pump 2
A discharge pipe 28 is connected to the outlet side of the discharge pipe 2.
8 has its tip connected to the tank 26 as shown in the figure.

When the tank 26 is filled with liquid up to the liquid level B, the liquid level A in the supply pipe 24 is at the same height as B as shown in the figure. When the pump 27 is started, the liquid level A rises due to its suction force, and the inside of the pressurizing chamber 14 is filled with liquid. Then, the liquid level A further rises, the inside of the discharge pipe 25 is also filled with liquid, and the liquid is further discharged into the discharge pipe 28. In this manner, the liquid in the tank 26 is sucked up by the operation of the pump 27, thereby forming a liquid circulation system as shown by the arrow in the figure.

In this state, the pressure inside the pressurizing chamber 14 is determined by the liquid transport capacity of the pump 27, the position (height) relationship between the tank 26 and the atomizing section 13, and the supply pipe 24,
A constant negative pressure is determined by the flow path resistance of the discharge pipe 25 and the discharge pipe 28. For this reason, nozzle 1
The outflow of liquid from 6 is prevented.

The piezoelectric vibrator 19 is provided with electrodes (not shown), and the electrodes are formed on the adhesive surface to the nozzle plate 17 and the surface opposite thereto.

When an alternating current voltage as shown in FIG. 4 a, b, or c is supplied between these electrodes, the piezoelectric vibrator 19 undergoes expansion and contraction strain in its diametrical direction depending on the polarity of the voltage. Since the piezoelectric vibrator 19 is bonded to the nozzle plate 17, this radial expansion/contraction strain is converted into flexural vibration as shown by the broken line in the figure, and as a result, the nozzle 16
vibrates in its axial direction, that is, in the left-right direction in FIG. Therefore, the liquid in the pressurizing chamber 14 is excited and the pressure increases, and the liquid drops 29 fly from the nozzle 16.

The power consumption of the piezoelectric vibrator 19 required to perform such a spraying operation is, for example, 10 c.c./min for kerosene.
When spraying at a rate of about 0.3Watts,
Stable spraying can be achieved with extremely low power and without being affected by cavitation bubbles. This is because air bubbles (not shown) generated near the center of the nozzle plate 17 due to cavitation,
Pressurized chamber 14 for the vibration mode as shown in the figure.
The pressure chamber 1
4, the discharge pipe 25, the pump 27, and the discharge pipe 2
8 and is released into the air within the tank 26. In order to achieve such smooth air bubble discharge, it is necessary to eliminate areas where air bubbles tend to accumulate between the pressurizing chamber 14 and the inlet of the pump 27.
The height is configured such that at least the height does not decrease (that is, it is horizontal or gradually increases) as the distance increases.

The amount of spray from this atomizer can be easily adjusted by simply controlling the AC voltage supplied to the piezoelectric vibrator 19 as shown in FIGS. 4a, b, or c.

Since the pump 27 only has to perform the function of sucking up liquid from the tank 26 and filling the pressurizing chamber 14, it has only the ability to suck up a height of, for example, about 50 to 100 mm, and its transport capacity is limited. The accuracy may be coarse. This is because the amount of spray from the atomizer 13 is determined mostly by the power supplied to the piezoelectric vibrator 19, and the volume of liquid equivalent to the atomized liquid is determined by the surface tension of the liquid generated at the nozzle 16. This is because it is naturally sucked up from the supply pipe 24. Therefore, by configuring the atomization device as shown in Fig. 3 using a very low-power, low-cost, and compact pump 27, it is possible to eliminate the difference in height between the tank and the pressurizing chamber and the change in the density of the liquid. According to etc.
It is possible to provide an atomization device that does not generate an air layer in the pressurized chamber 14 or cause liquid to overflow outside the device, and can perform an extremely stable atomization operation. Furthermore, as is clear from the above description, the pressure inside the pressurizing chamber 14 is always lower than the outside air pressure of the nozzle 16, so no liquid overflows from the nozzle 16 to the outside. With this configuration, it is possible to provide an atomizing device in which the liquid does not overflow from the nozzle and stain the outside, and the spraying operation does not become unstable due to overflowing liquid.

FIG. 5 is a sectional view of an atomizing device showing another embodiment of the present invention, and the same reference numerals as in FIG. 3 indicate corresponding structures, and their explanation will be omitted.

In the figure, the supply port 22 and the discharge port 23 are both provided on the bottom surface of the pressurizing chamber 14 facing the nozzle plate 17, and are configured to be connected to the discharge pipe 25 and the supply pipe 24 on a single surface of the body 15. There is. Further, the discharge pipe 28 is connected to the tank 26 at a position lower than the liquid level B of the tank 26. Therefore, the liquid level A' exists in the discharge pipe 28 before the pump 27 is started, but even in this case, the same effect as in the case of FIG. 3 can be achieved.

FIG. 6 is a cross-sectional view of an atomizing device showing still another embodiment of the present invention, and the same reference numerals as in FIGS. 3 and 5 indicate corresponding structures.

In the figure, the supply port 22 is provided at the center of the surface of the pressurizing chamber 14 facing the nozzle plate 17, and is configured to spray upward.
By making the liquid flow as shown by the arrow in the figure, air bubbles (not shown) caused by cavitation are reliably exhausted from the outlet even with this configuration, and stable spraying operation is maintained. It is possible to do so.

FIG. 7 is a sectional view of an atomizing device showing another embodiment, and the same reference numerals as in FIG. 3 indicate corresponding structures.

In the same figure, the discharge pipe 25 is constructed diagonally so that the position closer to the pump 27 is higher until it reaches the inlet of the pump 27, so that cavitation bubbles (not shown) can be discharged more smoothly. This is what I did. In addition, the liquid level B of the tank 26
is located a little higher than the pressurized chamber 14,
Therefore, before starting the pump, there is a liquid level in the discharge pipe 25.
In this case, if B is set too high above the nozzle 16, the liquid will overflow from the nozzle 16, but due to the surface tension of the liquid, the liquid will not overflow from the nozzle (or overflow). (in cases where it is acceptable) such a configuration can be adopted.

Of course, even in such a configuration, when the pump 27 is activated, the pressure inside the pressurizing chamber 14 becomes lower than the outside air pressure at the nozzle 16 due to the pressure loss due to the flow path resistance of the supply pipe 24. This makes it possible to perform stable spraying, and moreover, during the spraying operation, the liquid is completely prevented from overflowing to the outside.

As described above, the present invention is shown in FIGS. 3 and 5 to 7.
It is possible to take various embodiments as shown in the figures, and also optionally, e.g.
In the figure, it is clear that it is also possible to adopt a configuration in which the outlet of the discharge pipe 28 does not return to the tank 26, and that many further embodiments are possible.

FIG. 8 is a sectional view of a combustion device to which an atomizer according to still another embodiment of the present invention is applied, and the same reference numerals as in FIG. 3 indicate corresponding structures.

In FIG. 8, kerosene is supplied to the tank 26 from a cartridge tank 30 as shown.
The tank 26, the atomizing section 13, and the pump 27 are connected through a supply pipe 24, a discharge pipe 25, and a discharge pipe 28 as shown in the figure, and the plunger type electromagnetically driven pump 27 operates as shown by the arrow in the figure. Kerosene circulates like this. At the same time, the combustion fan 31
is started, air flows as shown by the arrow in the figure, and pre-purge is performed. Next, an AC voltage as shown in FIG. 4 a, b, or c is supplied to the piezoelectric vibrator of the atomization unit 13, and atomized particles (atomized droplets) 29 are atomized, and an igniter (not shown) is activated. ignites and burns. Since many of the air jet ports 32 are distributed above the combustion tube 33, the flame 34 is generated only above the combustion tube 33 as shown in the figure, resulting in blue flame combustion.

The atomizing section 13 is placed in a high-temperature atmosphere as shown in the figure, but the kerosene in the tank 26 is circulated by a pump 27, so the atmospheric temperature in the tank 26 is low.
And since the heat dissipation area is sufficiently larger than the atomization part 13,
The atomization section 13 receives a good cooling effect. In other words, since kerosene having a sufficiently low temperature is circulated through the atomizing section 13 by the pump 27, the piezoelectric vibrator, adhesive layer, etc. of the atomizing section 13 have a temperature that is very low compared to the ambient temperature. It is maintained.
Therefore, such a configuration prevents a temperature increase due to heat generation of the piezoelectric vibrator and a decrease in reliability of the piezoelectric vibrator due to placing the atomizing section 13 in hot water, and guarantees extremely high reliability. It is possible to realize an atomization device that can.

Effects of the Invention As described above, according to the present invention, the nozzle faces the pressurized chamber and is vibrated by an electric vibrator to spray, and the pressurized chamber is provided with a supply port and a discharge port. , each is connected to a tank and a liquid transport means, and the liquid is transported by the liquid transport means to fill the pressurized chamber, so the difference in height between the tank and the pressurized chamber and the density of the liquid It is possible to realize an atomization device with a very compact configuration, which can reliably fill a pressurized chamber with liquid regardless of the circumstances, and can atomize liquid extremely stably and with low power consumption.

Furthermore, it is an object to realize an atomizing device that does not have any inconveniences such as liquid overflowing from a nozzle, discharge pipe, etc. and contaminating the device, or liquid adhering to the outer surface of a nozzle plate and causing an unstable spray state. is possible.

Also, since the liquid is transported through a pressurized chamber,
In particular, it is possible to prevent the temperature rise of the electric vibrator and provide a highly reliable atomization device, as well as to guarantee stable and reliable atomization operation even in high-temperature atmospheres. be.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional atomizing device, FIG. 2 is a driving voltage waveform diagram of piezoelectric ceramic of the same atomizing device, FIG. 3 is a sectional view of an atomizing device according to an embodiment of the present invention, and FIG. Figures a, b and c are piezoelectric vibrator driving voltage waveform diagrams according to the spray amount of the same atomizer, Figure 5 is a sectional view of the atomizer of another embodiment of the present invention, and Figure 6 is the same. FIG. 7 is a sectional view of an atomizing device according to yet another embodiment, and FIG. 8 is a sectional view of an atomizing device according to yet another embodiment. FIG. 14... Pressure chamber, 15... Body, 16... Nozzle, 19... Electric vibrator, 22... Supply port, 23...
Discharge port, 26... Tank, 27... Liquid transport means (pump).

Claims (1)

[Scope of Claims] 1. A body having a pressurized chamber filled with liquid, a nozzle provided to face the pressurized chamber, and an electrical device that vibrates the liquid in the pressurized chamber and sprays it from the nozzle. The pressurized chamber is provided with a supply port and a discharge port, and the supply port and the discharge port are connected to the tank and the liquid transport means. An atomizing device configured to be connected to a transportation means and to fill the pressurized chamber with a liquid. 2. The atomizing device according to claim 1, wherein the amount of liquid transported by the liquid transporting means is larger than the amount of spray sprayed from the nozzle. 3. The atomization device according to claim 1 or 2, wherein the liquid transport means is an electric pump. 4. The atomization device according to claim 1 or 2, wherein the discharge side of the liquid transport means is connected to the tank to circulate the liquid. 5. Claim 4, wherein the amount of heat dissipated from the tank is greater than the amount of heat dissipated from the body, and the body is cooled by circulation of liquid.
Atomization device as described in section. 6. The atomization device according to claim 1 or 2, wherein the transportation means is located at a position equal to or higher than the pressurizing chamber.