JPS61141955A - Liquid jet apparatus - Google Patents

Abstract

PURPOSE:To stabilize the injection of a liquid containing dissolved air, by allowing the acoustic energy emitting surface of a vibrator to face to the wall surface opposed to the nozzle of a pressure chamber and providing a non- acoustic energy emitting surface to the circumference thereof. CONSTITUTION:A nozzle 2 is provided to a nozzle part 17 which is, in turn, mounted to a sub-body 18 by welding while a vibrator 25 consisting of a vibration plate 24 and piezoelectric ceramic 5 is mounted to a body 7. This vibrator 25 can substantially vibrate only the acoustic energy emitting surface 26 faced to the opening 4 of a vibration plate 24 by setting the thickness ratio of the piezoelectric ceramic 5 and the vibration plate 24 to about 10-20 and the part of the circumference thereof comes to a non-acoustic energy emitting surface 27. As mentioned above, because the nozzle 2 is not formed as a part of the vibrator 25, stable injection is performed and the contamination of the vibrator 25 by liquid droplets is eliminated and the diameter of the nozzle can be freely selected.

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 a spraying device for atomizing various liquids such as water, liquid fuel, and chemical solutions. The present invention relates to an ultrasonic liquid ejecting device that excites liquid in a pressurizing chamber by using ultra-rl wave vibrations such as ultrasonic waves, and ejects the liquid from a nozzle.

Conventional technology The conventional technology for this type of liquid ejecting device is the inkjet technology used in printers, etc. Recently, the inkjet technology has been improved to create a nozzle plate with nozzles facing the pressurizing chamber. There is a technique in which a piezoelectric vibrator is used to vibrate the liquid, and the sound pressure generated by the vibration causes liquid in a pressurized chamber to be sprayed from a nozzle. (
For example, JP-A-58-67374, Institute of Electronics and Communication Engineers Technical Research Report USS4-4. P, 23-30) No. 8
The figure is a sectional view of a spray device showing the latter example of the above-mentioned prior art.

In the figure, a spraying section 1 has a plurality of nozzles 2 with a diameter of 0.08 mm, a nozzle plate 3 with a thickness of 0.05 mm,
A conical piezoelectric ceramic 5 having an outer diameter of 5 to 15 mm and a thickness of about 0.5 to 10 mm, and a conical piezoelectric ceramic 5 having a depth of several mm.
A body 7 having a cylindrical pressurizing chamber 6,
It is connected to a tank 10 and a suction fan 11 by pipes 8 and 9, respectively. 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 becomes balanced at the liquid level 13 in the figure. In this state, the piezoelectric ceramic 5 is not energized, so the static pressure in the pressurizing chamber 6 is in front (outside) of the nozzle 2.
The pressure is lower than that of

Therefore, the liquid does not flow out from the nozzle 2, and a stable liquid layer jetting operation as described later can be realized.

Electrodes are provided on the left and right surfaces of the piezoelectric ceramic 5 (not shown), and when an AC voltage of 2O-100kHz is supplied between these electrodes, the nozzle plate 3 and the piezoelectric ceramic 5
It deflects and vibrates like the broken line in the garden. As a result, a strong sound pressure is generated in the vicinity of the nozzle 2 in the pressurizing chamber 6, and droplets 14 are ejected from the nozzle 2 according to the polarity of the AC voltage and are atomized.

Unlike inkjet devices, spraying devices that operate with this type of spraying 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. It has the advantage of being structured.

The problem that the invention seeks to solve Such conventional injection devices have the following drawbacks.

As described above, the structure of the conventional injection device is such that the nozzle plate 3 is flexibly vibrated by the piezoelectric ceramic 5 so that only the portion of the nozzle plate 3 near the area where the nozzle 2 is provided is strongly excited. For this reason, the thickness, material, diameter, etc. of the nozzle plate 3 and the piezoelectric ceramic 5 are limited in order to realize an efficient vibration system, and it is difficult to freely select the diameter and number of the nozzles 2. That is, it is difficult to make the nozzle 2 have an arbitrary diameter or number in order to spray a general liquid containing dissolved air with an arbitrary injection amount or particle size depending on the purpose.

6-・ In addition, the droplet jetted from the nozzle 2 is connected to the piezoelectric ceramic 5
If the surface of the piezoelectric vibrator becomes dirty due to wetting it,
This has the disadvantage that the piezoelectric vibrator may be damaged depending on the type of liquid that is injected, which limits its use.

Furthermore, the lead wires 15 and 16 for energizing the piezoelectric ceramic 5 have to be on the droplet injection side, which also has the problem of getting wet with the droplets and getting dirty.

Another problem is that, because of the above-described configuration, it is impossible to apply the method to applications where droplets are injected into high temperature or highly oxidizing spaces.

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

That is, a body having a pressurizing chamber, a nozzle facing the pressurizing chamber, a vibrating body that vibrates the liquid in the pressurizing chamber and spraying it from the nozzle, and a body that makes the static pressure of the pressurizing chamber lower than the pressure outside the nozzle. Nf
The acoustic energy emitting surface of the vibrating body is configured to face the wall surface facing the nozzle of the pressurizing chamber, and a non-radiating surface having a larger area than the emitting surface is provided around the emitting surface. This is a pressurized chamber.

Effect of the Invention The present invention has a structure consisting of the above-mentioned means, so that a general liquid can be stably jetted without using the nozzle plate as a diaphragm, and moreover, the vibrating body and the electric vibrator that energizes the vibrating body can be controlled in the jetting direction of the droplets. This realizes a liquid ejecting device located on the opposite side of the Therefore, the degree of freedom in ejecting the amount and particle size of the droplets ejected by the liquid ejecting device is increased, and the range of applicable liquids is greatly expanded.

Embodiment FIGS. 1(&), fbl, and (c) are a left side view, a sectional view, and a right side view, respectively, of a liquid ejecting device showing an embodiment of the present invention.

In FIG. 1, the same reference numerals as in FIG. S indicate corresponding structures, and their explanation will be omitted. In FIG. 1, the nozzle 2 is provided in a nozzle part 17, and the nozzle part 17 is installed in a subbody 18.
It is attached by welding or brazing. The nozzle section 17 does not need to vibrate itself, as will be described later. For this reason, the nozzle 2 can be adjusted depending on the amount and particle size of the ejected droplets.
It is possible to scrape with the optimum material and thickness for the required number and diameter of the plate, and it can be made of not only metal materials such as stainless steel and duralumin, but also materials such as silicon plates and fine ceramic plates. can. Therefore, 1
It is possible to easily realize several thousand nozzles 2 with a diameter of several micrometers to several hundred micrometers using a material and plate thickness suitable for the purpose using microfabrication manufacturing techniques such as photoetching and laser processing. Sub body 18 is attached to body 7 with screw 19~
22 and sealed with an O-ring 23.

A vibrating body 25 consisting of a vibrating plate 24 and an annular piezoelectric vibrator (piezoelectric ceramic) 5 is attached to the body 7 .

This vibrating body 25 can be made substantially Part 2 of the diaphragm 24 facing the opening 4
6 can be configured to vibrate. That is,
This part becomes an acoustic radiation surface (acoustic energy radiation surface) 26, and the surrounding part becomes a non-acoustic radiation surface 27. Actually, as shown by the broken line, the non-acoustic radiation surface 27 also vibrates in a phase opposite to that of the acoustic radiation surface 26, but since the amplitude is small and the phase is negative, it can be regarded as a non-acoustic radiation surface.

The annular piezoelectric vibrator 5 is energized at 20 to 100 kHz, and the depth of the pressurizing chamber 6, that is, the nozzle 2 and the acoustic radiation surface 2
The distance of 6 is 174 of the sound wave radiated from the acoustic radiation surface 26.
Since the wavelength is selected to be below the wavelength, the droplets 14 are ejected in substantially the same phase as the vibration of the acoustic radiation surface 26 as shown in the figure.

Note that 28 is a screw for removing air from the pressurizing chamber 6, and 29 is an O-ring.

FIGS. 2 (fal, fbl, and fc) are diagrams for explaining the operating principle of the liquid injection device in FIG. ,
and a pressure distribution diagram.

10' In the same figure +bl, the vibrating body 25 in FIG. This is the surface facing the pressurized chamber 61 and the non-acoustic radiation surface 27
is the surrounding surface. This piston vibrating body 3o vibrates the piston in the left-right direction in the figure, and sends sound e toward the nozzle 2 placed coaxially with the piston vibrating body 3o. This sound pressure causes nozzle 2
From there, droplets 14 are ejected. Sound radiation surface 26
If the distance between the nozzle 2 and the nozzle 2 is sufficiently smaller than the 174 wavelength of the sound wave, the sound pressures on the acoustic radiation surface 26 and the nozzle 2 will be in phase, and the droplet 14 will be ejected in accordance with the vibration phase of the piston vibrator 30.

If we consider the static pressure distribution inside the pressurized chamber 6, the figure fa
l, and there is a so-called radiation pressure Δ in the area A of radius r1.
p is generated, and a corresponding negative pressure car Δp is generated in the area jlB around it. Therefore, the static pressure distribution within the pressurizing chamber 6 can be modeled and expressed as shown in fc) of the same figure. As is clear from the figure [c], the static pressure distribution in the pressurizing chamber 6 becomes lower as the distance from the nozzle 2 increases. Therefore, even ordinary liquids containing dissolved air can be injected extremely stably. With Nasase, the sound pressure can be concentrated only in the vicinity of the nozzle 2, making it difficult for cavitation bubbles to occur, and even if cavitation bubbles occur, the static pressure distribution within the pressurizing chamber 6 will cause cavitation bubbles to form on the nozzle 2 and the acoustic radiation surface 26. This is because they will be excluded from the

As described above, the liquid injection device of FIG. 1 according to the present invention is based on the operating principle shown in FIG. The conventional problem can be solved by arranging the droplet 14 to be located on the opposite side to the direction in which the droplet 14 is ejected.

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

In FIG. 3, the nozzle portion 17 is provided with a protrusion 31, and a plurality of nozzles 2 are arranged on this protrusion 31. Therefore, the spray pattern of the droplets 14 can be dispersed. Further, the bubbles 32 generated by cavitation are quickly exhausted to the pipe 9 by the static pressure distribution in the pressurizing chamber 6 and gravity, as shown in the figure, and the liquid layer injection operation is kept extremely stable.

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. 1, the nozzle part 17 does not have a protrusion, but is provided with a plurality of nozzles 2, and can generate a plurality of droplet arrays in a straight pattern as shown in the figure. .

FIG. 5 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 the figure, the nozzle portion 17 has a protrusion 31 and a plurality of nozzles 2 are provided, but the protrusion direction of the protrusion 31 is in the direction of the pressurizing chamber 6. With this configuration, the jetted droplets 14 can be combined before their kinetic energy is lost due to air friction, and can be jetted as a liquid column 33 having considerable kinetic energy.

13B, FIG. 6 shows still another embodiment of the present invention, and the same reference numerals as in FIG. 3 indicate corresponding structures, and the explanation thereof will be omitted. In the figure, the vibrating body 25 is a so-called Langevin type piezoelectric vibrator 4o consisting of piezoelectric vibrators 36 and 37 connected to the vibrating plate 3 by buried wires 35, and bolts 38 and nuts 39 that fix them to each other. It vibrates in the thickness direction. This Langevin type piezoelectric vibrator 40
is fixed with an insulating member 41 that electrically and vibrationally insulates it from the body 7, and this insulating member is connected to the fixing plate 4.
2 is attached to the body 7. Since the vibrating body having such a configuration does not have an adhesive portion, high reliability can be obtained.

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

This figure shows that the diaphragm 34 of the vibrating body 25 can be configured in a horn shape and can be attached to the body 7ζ at its vibration node 43. That is, as shown in the figure, by fixing with screws 44 and 45 at the position where the amplitude δ becomes zero, it is possible to realize a liquid ejecting device with high efficiency operation.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) The acoustic energy emitting surface of the vibrating body faces the wall facing the nozzle of the pressurizing chamber, and a non-acoustic energy emitting surface is provided around it, so the vibrating body does not include the nozzle. It is possible to realize a liquid injection device that can extremely stably inject a general liquid containing dissolved air.

(2) Furthermore, since the nozzles do not form part of the vibrating body, dimensions such as material and plate thickness can be selected independently from the structural conditions of the vibrating body, and therefore the number and diameter of the nozzles can be selected independently. It is possible to realize a liquid ejecting device that can freely set and eject droplets with a required ejection amount and particle size.

(3) Furthermore, since the vibrating body is provided on the wall facing the nozzle of the pressurizing chamber, the vibrating body is located on the opposite side of the direction in which the droplets are ejected from the nozzle. ■-It is possible to realize a device that does not become contaminated by a single liquid layer that is sprayed by an electric motor.

In addition, adverse conditions such as high temperatures or strong acidity1
Even in this case, it is possible to realize a liquid ejecting device that can eject a liquid layer while protecting the vibrating body.

[Brief explanation of the drawing]

FIG. 1 (at, (bl, (cl) is a left plan view, a sectional view, and a right plan view of an injection device showing one embodiment of the present invention,
Figures fat, fbl, and fcl are a diagram of the static pressure distribution area in the pressurized chamber of the same device, a modeled configuration diagram, and a diagram of the static pressure distribution in the pressurized chamber. 4 is a sectional view of an injection device showing still another embodiment of the present invention, FIG. 5 is a sectional view of an injection device showing another embodiment of the invention, and FIG. Injection shaft 2... Nozzle 5... showing yet another embodiment of the invention
...Electric vibrator, 6... Pressure chamber, 7...
...Body, 1o...Tank (1 stage that maintains the static pressure in the pressurized chamber at a pressure equal to or lower than the pressure outside the nozzle), 24...Photography Board, 25...
... Vibrating body, 26... Acoustic energy; Emission surface, 27... Non-radiation surface. Name of agent: Toshio Nakao, IF Physician, and one other person

Claims (8)

[Claims] (1) A body having a pressurized chamber filled with liquid, a nozzle provided to face the pressurized chamber, a vibrating body that vibrates the liquid and sprays it from the nozzle, and the pressurized chamber means for maintaining the static pressure at a pressure substantially equal to or lower than the pressure outside the nozzle, and a configuration in which the acoustic energy emitting surface of the vibrating body faces a wall surface of the pressurizing chamber facing the nozzle. A liquid ejecting device, wherein the pressurizing chamber is configured to have a non-emitting surface around the emitting surface. (2) The liquid ejecting device according to claim 1, wherein the distance between the nozzle and the radiation surface is shorter than 1/4 of the wavelength of the sound wave emitted from the vibrating body. (3) The liquid ejecting device according to claim 1, wherein the vibrating body includes a plate-shaped or horn-shaped vibrating section and an electric vibrator that biases the vibrating section. (4) Claim 3, wherein the vibrating body is constituted by a flexible vibrating body consisting of a disc-shaped diaphragm and an annular piezoelectric vibrator, and a nozzle is provided approximately on the central axis of the piezoelectric vibrator. The liquid injection device described. (5) A patent in which the flexural vibrator is configured such that nodes of vibration occur almost along the inner diameter of the piezoelectric vibrator, the diaphragm inside the inner diameter is a radiation surface, and the outside of the inner diameter is a non-radiation surface. A liquid ejecting device according to claim 4. (6) The liquid ejecting device according to claim 3, wherein the vibrating body is a Langevin piezoelectric vibrator. (7) A liquid ejecting device according to claim 1, which includes a plurality of nozzles. (8) Liquid injection according to claim 1, wherein a nozzle plate having a nozzle is provided with a protrusion, and the nozzle is arranged on the protrusion so as to form a spray pattern in which droplets sprayed from the nozzle are dispersed or concentrated. Device.