JPH0373340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a spraying device for atomizing various liquids such as water, liquid fuel, and chemical solutions, and more specifically, to The present invention relates to an ultrasonic spraying device in which liquid in a pressurizing chamber is vibrated by ultrasonic vibrations of a child, and the liquid is sprayed from a nozzle to atomize the liquid.

Conventional technology The conventional technology related to this type of ultrasonic atomization device is the inkjet technology used in printers, etc. Recently, the inkjet technology has been improved to create a nozzle that has a nozzle facing the pressurizing chamber. There is a technique in which a plate is vibrated by a piezoelectric vibrator, and liquid in a pressurized chamber is sprayed from a nozzle by the sound pressure generated by the vibration (for example, Japanese Patent Application Laid-Open No. 122070/1983, IEICE Techniques Research report US84-4, P.23-30). FIG. 8 is a sectional view of a spray device showing the latter example of the prior art.

In the figure, the spraying section 1 has a plurality of nozzles 2 with a diameter of 0.08 mm, and a nozzle plate 3 with a thickness of 0.05 mm.
It is composed of an annular piezoelectric ceramic 5 having an opening 4 with an outer diameter of 5 to 15 mm and a thickness of about 0.5 to 2.0 mm, and a body 7 having a cylindrical pressurizing chamber 6 with a depth of several mm. , tanks 10 by pipes 8 and 9, respectively.
and is connected to the suction fan 11.

Due to the negative pressure generated by the suction fan 11, the liquid level in the pipe 8 is sucked up by a height hs from the same position as the liquid level 12 in the tank 10, and is balanced to the liquid level 13 in the figure.

Electrodes are provided on the left and right surfaces of the piezoelectric ceramic 5 (not shown), and 20-
When an AC voltage of 100 KHz is supplied, the nozzle plate 3 and the piezoelectric ceramic 5 bend and vibrate as shown by the broken line in the figure. As a result, strong sound pressure is generated in the vicinity of the nozzle 2 in the pressurizing chamber 6, and droplets 14 are emitted from the nozzle 2.
is injected and atomized according to the polarity of the AC voltage.

Unlike inkjet devices, spray devices that operate with this type of spray mechanism can spray extremely stably even liquids that contain a large amount of dissolved air, consume significantly less power, and are extremely compact and simple. However, it is essential that the pressure (static pressure) in the pressurizing chamber 6 is lower than the pressure in front of the nozzle 2 (ie, atmospheric pressure). If this is not the case, sound pressure will be generated in the vicinity of the nozzle 2 in the pressurizing chamber 6 where the liquid overflows from the nozzle 2 and cannot be injected normally.

FIG. 9 is a characteristic diagram showing the change in the amount of liquid sprayed q with respect to the pressure Pc in the pressurizing chamber 6 of the spray device shown in FIG. As is clear from the figure, when the pressure Pc in the pressurizing chamber 6 becomes higher than the atmospheric pressure (Pc>O), the spray amount q decreases drastically and normal liquid injection becomes impossible. In order to prevent such a situation, the pressurizing chamber 6 is filled with liquid using the negative pressure of the suction fan 11, and the pressure Pc inside the pressurizing chamber 6 is made lower than atmospheric pressure. .

Problems to be Solved by the Invention As described above, the conventional spraying device required the suction fan 11 to generate the negative pressure Ps for filling the pressurized chamber 6 with liquid. This negative pressure Ps is
For example, if the suction height hs is 50 mm and the liquid is water, it is 50 mm.
Aq is necessary. Therefore, the suction fan 11 becomes an extremely large fan, making the entire device very large and expensive, and not only does it generate significant noise, but if the spray device falls over, liquid will overflow from the pipe 9. This has the disadvantage of not only contaminating the spray device and its surroundings, but also being extremely dangerous depending on the type of liquid. In addition, the average spray amount q
When the voltage supplied to the piezoelectric ceramic 5 is controlled intermittently to adjust the liquid level 12 of the tank 10,
This has the disadvantage that the spray amount q varies significantly due to variations in the liquid level 13 due to changes in the height of the spray. This is due to the inertia of the liquid flow.

Means for Solving the Problems The present invention has been made to solve the drawbacks of such conventional spray devices, and is constructed by the means described below.

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, and a liquid that imparts energy such as position or pressure to the liquid. comprising a biasing means, a supply pipe connecting the pressurizing chamber and the liquid biasing means, and a discharge pipe having an end open to the atmosphere located at a position lower than the pressurizing chamber and the other end connected to the pressurizing chamber, The pressure drop between the supply pipe and the discharge pipe, and the pressure drop between the pressurized chamber and the atmosphere open end are reduced so that the energy lost due to the flow of liquid through the discharge pipe is smaller than the energy given by the difference in position (height) between the pressurized chamber and the end open to the atmosphere. This is the configuration of the positional relationship with the end.

Effect: With the configuration consisting of the above-mentioned means of the present invention, the pressurized chamber is filled with liquid without using a suction fan, and a flow of liquid is formed to exhaust the air in the pressurized chamber.
Furthermore, the pressure inside the pressurizing chamber is maintained at a pressure lower than the pressure in front of the nozzle (atmospheric pressure), thereby realizing a stable spraying operation by the electric vibrator.

Embodiment FIG. 1 is a sectional view of a spray device showing an embodiment of the present invention.

In FIG. 1, the same reference numerals as in FIG. 8 indicate corresponding structures, and their explanation will be omitted. In the figure, the pressurizing chamber 6 is connected to a discharge pipe 15 and a supply pipe 16, and the end 17, which is the tip of the discharge pipe 15 and which is open to the atmosphere, is located at a position lower than the center of the pressurizing chamber 6 by h1. It is configured like this. On the other hand, the other end of the supply pipe 16 is connected to the first
It is connected to a liquid tank 18, and the liquid level 19 of the first liquid tank 18 is configured to be at a position higher than the center of the pressurizing chamber 6 by h2. That is, the first liquid tank 18 applies positional (height) energy to the liquid in the liquid tank, and causes the liquid to flow from the pressurizing chamber 6 to the discharge pipe 15 via the supply pipe 16 as indicated by the arrow in the figure. and forms a liquid biasing means.

A second liquid tank 21 having a liquid level 20 is provided at a position lower than the atmosphere open end 17 of the discharge pipe 15, and the liquid flowing out from the atmosphere open end 17 flows into the second liquid tank 21 as shown in the figure. ing.

Here, the configurations of the discharge pipe 15 and the supply pipe 16 will be explained. As shown in the figure, the cross-sectional area of the discharge pipe 15 is configured to be sufficiently larger than the cross-sectional area of the supply pipe 16.
For this reason, the difference in flow velocity of the liquid flowing inside the two pipes 15 and 16 is extremely large. Therefore, the water head (h1
The liquid that has been given energy of +h2) consumes most of its energy as internal pressure loss in the supply pipe 16. On the other hand, the position of the pressurized chamber 6 between the atmosphere open end 17 and the liquid level 19 is h1/(h1+h2)
Therefore, the liquid in the pressurized chamber 6 is h1/
It has potential energy equivalent to (h1 + h2).

This potential energy is larger than the energy consumed by the liquid flowing inside the discharge pipe 15 (pressure loss inside the discharge pipe 15), and therefore the inside of the pressurizing chamber 6 acts like a negative pressure section in a kind of siphon. As a result, the pressure becomes lower than atmospheric pressure (the pressure in front of the nozzle 2).

FIGS. 2a and 2b are diagrams modeling the position change of the pressure (static pressure) Pst in the liquid flow path in FIG. 1 and the liquid flow path. Discharge pipe 1 in Figure b, ignoring pipe inlet loss, bending loss, etc.
If the cross-sectional areas of 5 and supply pipe 16 are equal, and the ratio of their lengths is equal to the ratio of h1 and h2, the position change of pressure (static pressure) Pst will coincide with straight line A indicating the hydraulic gradient and the applied The pressure inside the pressure chamber 6 becomes equal to atmospheric pressure. However, since the cross-sectional area of the discharge pipe 15 is larger than the cross-sectional area of the supply pipe 16, the pressure (static pressure) Pst becomes as shown in a in the same figure, and the pressure is lower than atmospheric pressure by the energy equivalent to hd shown in the figure. (static pressure) Pst, which becomes the internal pressure pc of the pressurizing chamber 6.

In FIG. 1, the tip of the discharge pipe 15 is above the liquid level 20, so the end 1 of the discharge pipe 15 is open to the atmosphere.
7 coincides with its tip, but if the discharge pipe 15
If the tip of the pipe is below the liquid level 20, the discharge pipe 15
It is clear that the position corresponding to the liquid level 20 in this case is the end open to the atmosphere. However, if the height of the liquid level 20 fluctuates greatly, it is advantageous to place the tip of the discharge pipe 15 above the liquid level 20 in order to ensure the stability of the spraying operation.

With this configuration, the air in the pressurizing chamber 6 can be discharged and filled with liquid using only the liquid channel system without using a dedicated liquid suction fan,
Moreover, stable spraying operation can be guaranteed by setting the internal pressure Pc of the pressurizing chamber 6 to an arbitrary pressure below atmospheric pressure, thereby realizing a spraying device that has a simple, compact configuration, is inexpensive, and has low noise. be able to. Furthermore, since the pressurizing chamber 6 is connected only to the liquid flow path system, it has the advantage that the structure for preventing liquid from flowing out in case of an abnormality such as a fall is simple.

FIG. 3 shows another embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate corresponding structures, and their explanation will be omitted.

In FIG. 3, the first liquid tank 18 is connected to the second liquid tank 21 by pipes 23 and 24 via a pump 22, and the first liquid tank 18 is connected to the atmosphere open end 17.
The liquid flowing out is pumped up from the second liquid tank 21 to the first liquid tank 18 by a pump 22. The first liquid tank 18 is configured to return from a return pipe 25 as shown in the figure.
Therefore, the liquid level 19 is kept constant regardless of the pumping capacity of the pump 22. Therefore, the supply pipe 16
The pressure (energy) of the liquid supplied to the pressurized chamber 6 is determined only by h2, and the pump 22 can be extremely simple and inexpensive.

An orifice 26 is provided in the middle of the supply pipe 16, so that the flow resistance of the supply pipe 16 can be reduced and the internal pressure Pc of the pressurizing chamber 6 can be kept constant regardless of its length or degree of bending. . Furthermore, by providing the orifice 26, even if bubbles 27 are generated due to cavitation due to the vibration of the nozzle plate 3, the diameter of the discharge pipe 17 can be reduced in order to increase the flow velocity of the liquid in the discharge pipe 17. It is possible to effectively discharge air bubbles.

Also in this embodiment, the internal pressure Pc of the pressurizing chamber 6
is determined only by h1, and from the liquid level 21 to the sprayer 1
It is unrelated to the height h3.

The atmosphere open end 17 has an inclined cross-sectional shape as shown in the figure, and by doing so, it is possible to prevent air bubbles 27 from accumulating at the atmosphere open end 17 due to the surface tension of the liquid.

FIG. 4 shows still 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. 4, the pump 22 is inserted midway through the supply pipe 16. Therefore, although the discharge pressure of the pump 22 needs to be somewhat stable, there is an advantage that the first liquid tank 18 in FIG. 3 can be omitted.

FIG. 5 shows another embodiment of the present invention,
Components with the same reference numerals as those in FIG. 3 are equivalent structures, and their explanation will be omitted.

In FIG. 5, the body 7 of the sprayer 1 includes an orifice 26, a pressure smoothing chamber 28, valves 29, 30,
The discharge chamber 31, the diaphragm 32, and the second piezoelectric ceramic 33 are integrally provided, making it possible to realize a compact structure. Since the diaphragm 32 and the second piezoelectric ceramic 33 flexurally vibrate as shown in the figure, they perform a pumping action together with the valves 29 and 30. Therefore, it is possible to perform the same good operation as the embodiment shown in FIG. 4 with a simple structure. Therefore, the configuration of the entire device can be made compact.

FIG. 6 shows yet 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 this embodiment, orifice 2 is installed in body 7.
Only 6 are integrated. Therefore, various means can be arbitrarily selected as the liquid urging means depending on the application.

FIG. 7 shows yet 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. 7, a motor 34 is installed in a fan 35 that blows air to convey or mix the droplets 14 sprayed from the sprayer 1, and a liquid tank 21 that urges and pumps the liquid. screwed screw 3
6 is coaxially driven. Therefore, in the case of an application having the blower fan 35 as described above, by adopting such a configuration, it is possible to simplify the configuration of the entire device without requiring a separate liquid urging means. .

Effects of the Invention As described above, according to the present invention, there is provided a body having a pressurizing chamber, a nozzle facing the pressurizing chamber, an electric vibrator for spraying the liquid in the pressurizing chamber, and a position or pressure on the liquid. a supply pipe connecting the pressurizing chamber and the liquid urging means, the end of which is open to the atmosphere is provided at a position lower than the pressurizing chamber, and the other end is connected to the pressurizing chamber. The system is equipped with a discharge pipe and is configured so that the energy loss when the liquid flows through the discharge pipe is smaller than the energy of the positional difference between the pressurized chamber and the end open to the atmosphere. It is possible to maintain the internal pressure Pc of the pressurizing chamber lower than the pressure in front of the nozzle while flowing the liquid into the pressurizing chamber, and as a result, it is possible to guarantee stable spraying operation. Therefore, since there is no need for suction means such as a large suction fan, the spray device can be made extremely small and
It can be made compact and low cost. In addition, since there is no need to generate suction pressure, noise is extremely low, and even in an abnormal situation such as the spraying device falling over, liquid will not leak into the suction fan and contaminate the inside and outside of the device. It is possible to provide an excellent spraying device that does not cause any inconvenience when a dangerous situation occurs. Furthermore, by opening one end of the discharge pipe to the atmosphere, the internal pressure of the pressurizing chamber can be kept constant regardless of the height between the liquid level in the liquid tank and the pressurizing chamber, and the internal pressure of the pressurizing chamber can be kept constant regardless of fluctuations in the liquid level in the liquid tank. It is possible to maintain the spray amount at a predetermined value without
A spray device that is extremely easy to use can be realized.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a spraying device showing an embodiment of the present invention, and Fig. 2 a and b show the internal pressure of the liquid flow path of the same device.
A diagram explaining the distribution of Pst, a configuration diagram modeling the liquid flow path of the device, and FIG. 4 is a cross-sectional view of a spraying device showing still another embodiment of the present invention in which the liquid urging means is constituted by liquid pressurizing means; FIG. 5 is a sectional view of the spraying device in which the liquid urging means is integrated into the body. FIG. 6 is a cross-sectional view of a spray device showing yet another embodiment in which an orifice is provided in the body, and FIG. 7 is a cross-sectional view of a spray device showing yet another embodiment of the present invention. FIG. 8 is a cross-sectional view of a spray device showing yet another embodiment that serves as both a droplet conveying fan and a liquid urging means. FIG. 8 is a cross-sectional view showing the configuration of a conventional spray device. FIG. FIG. 2 is an explanatory diagram showing the relationship between the pressurized chamber pressure Pc and the spray amount q of the same device. 2... Nozzle, 3... Nozzle plate, 5... Electric vibrator, 6... Pressurizing chamber, 7... Body, 15...
...Discharge pipe, 16... Supply pipe, 17... Atmospheric open end, 18... First liquid tank (liquid urging means), 21...
...Second liquid tank, 22...Pump (liquid urging means),
26... Orifice, 29, 30... Valve, 31...
...Discharge chamber, 32...Vibration plate, 33...Second piezoelectric ceramic, 29, 30, 31, 32, 33...Liquid urging means, 34...Motor, 35...Fan,
36...screw, 34,36...liquid biasing means.

Claims (1)

[Scope of Claims] 1. A body having a pressurized chamber filled with a liquid, a nozzle provided to face the pressurized chamber, and electricity that vibrates the liquid in the pressurized chamber and sprays it from the nozzle. a liquid energizing means for applying energy such as position and pressure to the liquid; a supply pipe connecting the pressurizing chamber and the liquid energizing means; and an end open to the atmosphere at a position lower than the pressurizing chamber. and a discharge pipe whose other end is connected to the pressurizing chamber, and the energy lost due to the liquid flowing through the discharge pipe is greater than the energy given by the positional difference between the pressurizing chamber and the atmospherically open end. A spray device configured to be small. 2. The spray device according to claim 1, wherein the liquid flowing out from the atmosphere-open end of the discharge pipe is stored in a liquid tank, and the liquid is circulated by a liquid urging means. 3. The spray device according to claim 2, wherein the end of the discharge pipe that is open to the atmosphere is located at a position higher than the liquid level of the liquid tank. 4. The spray device according to claim 1, wherein the cross-sectional area of the supply pipe is smaller than the cross-sectional area of the discharge pipe. 5. The spray device according to claim 1, wherein an orifice is provided between the pressurizing chamber and the liquid urging means. 6. The spray device according to claim 5, wherein the orifice is integrated into the body. 7. The spray device according to claim 1, wherein the discharge pipe is configured to have a cross-sectional area that allows the interior of the discharge pipe to maintain a liquid-filled state up to its end open to the atmosphere due to the surface tension of the liquid. 8. The spray device according to claim 7, wherein the end of the discharge pipe open to the atmosphere has an inclined cross-sectional shape. 9. The spray device according to claim 1, wherein the body and the liquid urging means are integrated into one body. 10. The spray device according to claim 1, wherein a supply pipe is connected to the lower side of the pressurized chamber, and a discharge pipe is connected to the upper side of the pressurized chamber. 11 A body having a pressurized chamber filled with liquid, a nozzle provided to face the pressurized chamber, an electric vibrator that vibrates the liquid in the pressurized chamber and sprays it from the nozzle, and a liquid a liquid urging means for applying energy such as position and pressure to the pressurizing chamber; a supply pipe connecting the pressurizing chamber and the liquid urging means; an end open to the atmosphere is provided at a position lower than the pressurizing chamber, and the other end is provided at a position lower than the pressurizing chamber; A discharge pipe connected to the pressurizing chamber and a blower for blowing air to mix with the droplets sprayed from the nozzle are provided, and the energy lost due to the liquid flowing through the discharge pipe is absorbed between the pressurizing chamber and the A spray device configured to have energy smaller than that given by a positional difference between ends open to the atmosphere, and configured to serve as both the liquid urging means and the blower.