JPS647832B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an atomization device for atomizing liquid fuel such as kerosene and light oil, water, and liquid such as chemical solution.
More specifically, the present invention relates to an atomizing device that vibrates liquid using an electric vibrator such as a piezoelectric vibrator and injects the liquid from a nozzle.

Conventional Structure and Problems Conventionally, this type of atomizing device has been mainly used as an ink spraying device of an inkjet recording device, and the structure shown in FIG. 1 is typical. In FIG. 1, an orifice 2 is provided at one end of an ink chamber 1, and a piezoelectric vibrator 3 and a diaphragm 4 are provided at the other end and are bonded to a body 5. The ink chamber 1 is connected to an ink tank 7 through a pipe 6 as shown in the figure, and is configured to be supplied with ink.

The body 5 is covered with a case 9 provided with an opening 8 coaxial with the orifice 2, and is configured such that air blown by a fan 11 in an air path 10 is guided as shown by the arrow in the figure.

When an alternating current voltage as shown in FIG. 2 is supplied to the piezoelectric vibrator 3, since the piezoelectric vibrator 3 and the diaphragm 4 have an asymmetric bimorph structure, flexural vibration as shown by the broken line in the figure occurs. A pressure wave within the ink chamber 1 generated by this bending vibration propagates through the ink within the ink chamber 1 and reaches the orifice 2 while being increased in pressure. Therefore, ink droplets 12 are ejected from the orifice 2 as shown in the figure.

The airflow generated by the blower fan 11 as shown by the arrow in the figure increases the flying speed of the droplets 12 and stabilizes the flying direction.

However, such conventional atomizing devices have the following drawbacks.

In other words, if the driving power of the piezoelectric vibrator is increased in order to increase the amount of liquid sprayed, the temperature of the piezoelectric vibrator will increase significantly, and if you try to use it in a high temperature atmosphere, the temperature will increase. This has the disadvantage that the temperature of the piezoelectric vibrator becomes high. In particular, when the electric vibrator is constructed of piezoelectric ceramics, operation under high temperature conditions causes serious drawbacks such as deterioration of polarization.Furthermore, when an adhesive structure is used, the adhesive strength decreases. There were disadvantages such as deterioration of characteristics due to For this reason, conventional atomization devices are used with a very small amount of atomization, and are only used in applications such as inkjet recording devices where the power consumption of the piezoelectric vibrator is extremely low and the ambient temperature is not high. It was extremely lacking in versatility.

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

The purpose of this is to prevent the temperature rise of the electric vibrator by providing a good cooling effect, even when the electric vibrator is used in a high-temperature atmosphere or when the loss of electric vibrators such as piezoelectric vibrators increases due to large amounts of spray. can prevent and maintain stable performance and high reliability,
Therefore, it is an object of the present invention to provide a highly versatile atomization device that can be applied to various uses.

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 provided facing the pressurizing chamber, an electric vibrator that vibrates the liquid in the pressurizing chamber and sprays it from the nozzle, and supplying the liquid to the pressurizing chamber. In addition to a liquid supply system for cooling the body directly or indirectly, the cooling liquid circulation system increases the amount of spray and generates electrical vibrations. Even when the loss of the element increases or when operating in a high-temperature atmosphere, the temperature rise of the electric vibrator and its bonded parts can be kept low.

DESCRIPTION OF EMBODIMENTS FIG. 3 is a sectional view of an atomization device showing an embodiment of the present invention.

In the figure, the body 13 has a diameter of 5 to 15 mm inside.
A cylindrical pressurizing chamber 14 with a depth of 1 to 5 mm is provided, and a nozzle plate 15 is mounted so as to cover one circular surface of the pressurizing chamber 14. Nozzle plate 1
5 is a metal plate having a thickness of 30 μm to 100 μm, and a plurality of nozzles 16 having a diameter of 30 μm to 100 μm are provided in the center thereof. This nozzle plate 15 has a diameter of 5 to 15 mm.
A ring-shaped piezoelectric vibrator 17 with a thickness of 0.5 to 2 mm is mounted as shown in the figure, and an opening 18 is provided in the center of the piezoelectric vibrator 17. Therefore, the structure is such that the nozzle 16 faces this opening 18.

The liquid to be sprayed is sent from an external tank (not shown) through a pipe 19 to a leveler 20 that maintains the liquid level A at a substantially constant level.
It is connected to the pressurizing chamber 14 at , thus configuring a liquid supply system.

Therefore, the liquid level B in the pipe 21 is
Due to the liquid level control effect of 0, when the operation is stopped, it is at the same height as the liquid level A as shown in the figure.

During operation, first, the motor 22 starts the blower fan 2.
3 is activated, air is sent through the orifice 24 as shown by the arrow in the figure, and becomes a swirling airflow in the swirler 25.

By this blower fan 23, the negative pressure generating section 26 downstream of the orifice 24 has a pressure of, for example, 30 to 40 mmAq.
A certain degree of negative pressure is generated, and this negative pressure is applied to the liquid level B via the exhaust pipe 27 and the pressurizing chamber 14. Therefore, the liquid level B rises and reaches the level of the liquid level C, resulting in a state as shown in the figure, and the pressurizing chamber 14 is filled with liquid.

After such a state is reached, an alternating current voltage as shown in FIG. 4 a, b, or c is supplied to the piezoelectric vibrator 17 according to the required amount of spray.

A joint surface of the piezoelectric vibrator 17 with the nozzle plate 15,
Although not shown, electrodes are provided on the surface opposite to this surface and are polarized in the thickness direction. When the alternating current voltage is supplied between the electrodes of the piezoelectric vibrator 17, an expansion/contraction strain occurs in the diametrical direction depending on the polarity of the alternating current voltage. Due to this expansion/contraction strain, the nozzle plate 15 and the piezoelectric vibrator 17 cause a flexural vibration as shown by the broken line in the figure as an asymmetric bimorph vibrator, and as a result, the nozzle 1
6 vibrates in the left-right direction in the figure, and the liquid in the pressurizing chamber 14 is vibrated and sprayed from the nozzle 16 as droplets 28 .

In this way, by simply applying an alternating current voltage to the piezoelectric vibrator 17, it is possible to spray the liquid while sucking it up from the leveler 20. This liquid suction action is caused by the surface tension of the liquid generated at the nozzle 16.

By applying the aforementioned alternating current voltage to the piezoelectric vibrator 17, the piezoelectric vibrator 17 causes a temperature rise due to power loss, and this temperature rise increases as the amount of spray increases.

As is well known, when the piezoelectric vibrator 17 operates at high temperatures, its electromechanical conversion efficiency is lowered or deteriorated, and in extreme cases, its reliability is significantly lowered, including damage. Therefore, a coolant circulation system consisting of a heat radiation tank 29, a circulation pump 30, a heat exchange section 31, and pipes 32 and 33 is provided.

Since the cooling liquid is circulated by the circulation pump 30 in the direction of the arrow in the figure, the body 13 is cooled well. Therefore, the heat loss of the piezoelectric vibrator 17 is radiated through the body 13, and the temperature rise of the piezoelectric vibrator is suppressed to a small level, and disadvantages such as changes in its characteristics and performance deterioration can be prevented. A large atomization amount can be freely obtained and the atomization device is highly compact.

Furthermore, by providing such a coolant circulation system, the temperature of the piezoelectric vibrator 17 can be maintained at a low temperature even in a high temperature atmosphere, without causing characteristic changes or performance deterioration due to being placed in a high temperature environment. It becomes possible to operate even in a high temperature atmosphere.

In this way, changes in the characteristics and performance deterioration of the piezoelectric vibrator 17 itself caused by self-heating of the piezoelectric vibrator 17 that occurs when obtaining a large amount of spray, and deterioration of the bonding layer due to thermal stress are prevented. Even when operating in a high-temperature atmosphere, the piezoelectric vibrator 17 and the like can be well cooled to ensure high reliability, so a highly versatile atomization device can be realized.

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 FIG. 5, the cooling liquid is also used as a liquid to be sprayed, and the liquid is passed from a tank 29' which also serves as a heat radiation tank to a circulation pump 3 through a pipe 33.
0, the flow flows as shown by the arrow in the figure. The liquid overflows from the inlet 34 of the return pipe 32 into the tank 29' and returns to the tank 29'. Therefore, the liquid level A in the case 35 is maintained substantially constant, and the body 13 is indirectly cooled by the circulating liquid via the pipe 21 and the case 35.

Although such a configuration has a slightly reduced cooling effect compared to the embodiment shown in FIG. This eliminates the problem of characteristic changes or deterioration that occur with operation, and achieves high reliability and high versatility.

FIG. 6 shows still another embodiment of the present invention, and the same reference numerals as in FIG. 5 indicate corresponding structures, and their explanation will be omitted.

In Figure 6, the body is cooled by pipe 2.
1 and case 35 through a heat radiator 36. In addition, by configuring the front surface of the piezoelectric vibrator 17 to be covered as shown in the figure, it is possible to have the effect of blocking radiant heat radiated from the front toward the piezoelectric vibrator. This is very effective in applications where 28 is sprayed into a high temperature field.

FIG. 7 is a cross-sectional view showing the configuration of a combustion device to which the atomization device of FIG. 5 is applied, and the same reference numerals as in FIG. 5 indicate corresponding structures.

In Figure 7, kerosene is stored in cartridge tank 3.
6 to a tank 29' which also serves as a heat radiation tank. The water is circulated between the case 35 and the tank 29' by the circulation pump 30 to cool the body inside the case 35.

The combustion fan 23 and the blower fan (negative pressure generation fan) 23' are driven by the motor 22, the liquid level of kerosene is sucked up to the position C in the figure, and then the piezoelectric vibrator in the case 35 is driven.

Therefore, the minute droplets 28 of kerosene are sprayed as shown in the figure, vaporized while flying by the heater 37, and sent to the burner 38 together with combustion air to be burned. 39 is an igniter, 40 is a flame, 41 is a flame rod, 42
is a convection fan.

The amount of combustion is determined by adjusting the drive voltage of the piezoelectric vibrator and the opening degree of the orifice 24 by means of an electromagnetic proportional control valve 43, as shown in FIGS.

In this way, the atomization device of the present invention has the heater 37
Even under high-temperature atmospheric conditions caused by the heat generated by the burner 38, its effective cooling effect suppresses the temperature rise of the piezoelectric vibrator, ensuring stable operation and high reliability.It is compact and easy to control. A good combustion device can be realized.

Effects of the Invention As described above, according to the present invention, the nozzle faces the pressurizing chamber provided in the body and the liquid in the pressurizing chamber is vibrated by an electric vibrator, and the cooling liquid circulation Since the system is designed to directly or indirectly cool the body, it is possible to spray a large amount of water even with a very compact structure, and when spraying a large amount, there is no need to worry about the self-heating of the electric vibrator, which is particularly noticeable. It is possible to suppress temperature rise and solve problems such as characteristic changes or deterioration caused by it. Furthermore, similar problems that occur when operating in high-temperature atmospheres can be resolved, and extremely stable performance and high reliability can be guaranteed even when spraying in large quantities or operating in high-temperature atmospheres. It is something. Therefore, it is extremely versatile, and
A compact atomization device can be realized, and its industrial value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional atomizing device, Fig. 2 is a piezoelectric vibrator driving voltage waveform diagram of the same device, Fig. 3 is a sectional view of an atomizing device according to an embodiment of the present invention, and Fig. 4 a ，
b and c are drive voltage waveform diagrams of the piezoelectric vibrator according to the spray amount of the same device, FIG. 5 is a cross-sectional view of the atomization device showing another embodiment of the present invention, and FIG. 6 is a diagram of another embodiment of the same. FIG. 7 is a sectional view of a combustion device to which the atomization device of FIG. 5 is applied. 13...Body, 14...Pressure chamber, 16...
Nozzle, 17...electric vibrator (piezoelectric vibrator),
19-21...Liquid supply system (19, 21...Pipe, 20...Leveler), 29-33...Cooling liquid circulation system (29...Radiation tank, 30...Circulation pump, 31...Heat exchange section , 32, 33...pipe).

Claims (1)

[Scope of Claims] 1. A body having a pressurizing chamber, a nozzle provided facing the pressurizing chamber, and an electric vibrator that vibrates the liquid in the pressurizing chamber and causes the liquid to be sprayed from the nozzle. An atomizer comprising: a liquid supply system that supplies liquid to the pressurizing chamber; and a cooling liquid circulation system that cools the body. 2. Atomization according to claim 1, wherein a liquid circulation system is provided in the liquid supply system, the liquid circulation system also serves as a cooling liquid circulation system, and the liquid to be sprayed is circulated as a cooling liquid. Device. 3. The coolant circulation system is configured to include a constant liquid level device that overflows at a constant liquid level height, and a circulation pump that supplies the coolant to the constant liquid level device, and a The atomizing device according to claim 1 or 2, wherein the atomizing device is configured to be cooled by attaching a body to the atomizing device. 4 Claims 1, 2, or 3 in which the body is directly immersed in the circulating coolant
The atomization device described in Section 1. 5. Claim 1, wherein a heat radiating part is provided in the body, and the heat radiating part is immersed in a cooling liquid.
The atomization device according to item 2 or 3.