JPH105561A - Atomizing method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently atomize various materials and to keep various costs low by using this atomizing device high in cleanability and capable of being easily made compact. SOLUTION: A material to be atomized and a fluid are passed through a chamber member 22 having a relatively large cross section and then through a member 24 provided with the part having a minute cross section. In this case, ultrasonic vibration is generated by the resonance between the chamber member 22 and the member 24, and a stress is repeatedly exerted on the material to be atomized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for atomization used in dispersion, emulsification, mixing, stirring, crushing and other fields.

[0002]

2. Description of the Related Art When various materials are atomized, for example, dispersion,
It is widely known that in the fields of emulsification, mixing, crushing and the like, the original function of the material is sufficiently exerted and extremely good results are obtained. Therefore, the development of a method and an apparatus for atomizing various materials has been strongly demanded.

[0003] Here, in the atomization apparatus, since the demand for purification (contamination-less) of the material is extremely high, a portion where fine particles may exist must be cleaned well.

Further, in the conventional atomizing apparatus, it is necessary to generate a high pressure. Therefore, it is necessary to provide a high-pressure pump, a compressor, and the like, so that the size and the price have to be increased. For this reason, in the conventional atomization apparatus, there has been a very strong demand for downsizing and improvement in cleanability.

[0005] Japanese Patent Application Laid-Open No. 2-2615 discloses a method in which a substance in a fluid is atomized by the occurrence of cavitation due to collision, disturbance, turbulence, expansion, or contraction of the fluid.
No. 25 discloses a technique in which a through hole and a groove are formed in a nozzle disk in a generator which is a member for atomizing a material. No. 4,533,254.
The specification discloses a technique in which a nozzle hole and a film-shaped chamber are combined. And according to these conventional techniques, atomization of the material can be achieved.

[0006]

However, in the above-mentioned prior art, the member for atomizing the material is such that the disk and / or the nozzle in the chamber is constituted by a flow path formed in a groove or a thin film-shaped chamber. However, there is a problem that stress concentration occurs at a bent portion in the flow channel, and the corner portion of the bent portion is worn and worn away.

In addition, since the area (contact surface area) between the fluid or the material to be atomized (particles) and the member is large, there is also a problem that cleaning properties are low.

Further, since the device for compressing the fluid is a compressor or a pump, if the pressure for achieving the predetermined atomization is to be obtained, there is a problem that the entire device becomes large. I have.

In addition, the maintenance cost is increased due to the low cleaning property, and the manufacturing cost is high due to the increase in size of the entire apparatus or the high performance (corresponding to high pressure), and the like. However, the conventional atomizing apparatus causes various costs to increase.

In the atomization treatment, it is ideal that the particle size of the atomized object can be freely designed, so-called "particle size design". However, in the prior art, such a particle size design was not possible.

The present invention has been proposed in view of the above-mentioned problems of the prior art, and is capable of satisfactorily atomizing various materials, has high cleaning properties, and is easy to make compact. It is an object of the present invention to provide an atomizing method and an apparatus capable of keeping various costs low.

[0012]

As a result of various studies, the present inventors have found that, instead of the conventional atomization by cavitation, atomization by a completely different theory, that is, atomization based on acoustic theory or resonance theory. It has been found that very good results can be obtained if done. The present invention relates to a method and an apparatus for atomizing by such a theory (completely different from the conventional theory of atomization by cavitation).

[0013] In the atomization method of the present invention, the material to be atomized is mixed with a fluid to atomize the material, and the material to be atomized and the fluid are passed through a chamber member having a relatively large cross-sectional area. Having a step of flowing through a member having a portion having a small cross-sectional area,
Ultrasonic vibration is generated by resonance between the chamber member, the portion having the minute cross-sectional area, and the fluid, and a stress is repeatedly applied to a material to be atomized.

Further, the atomizing device of the present invention is a device for atomizing a material to be atomized by mixing the material to be atomized with a fluid, the chamber member having a relatively large sectional area, and a portion having a small sectional area. And a supply piping system for supplying the material and the fluid to be atomized to the chamber member and a member having a portion having a small cross-sectional area,
The member provided with the chamber member and the portion having a small cross-sectional area, in order to repeatedly apply stress to the material to be atomized, the chamber member and the portion having a small cross-sectional area and the fluid cause resonance It is configured to generate ultrasonic vibration.

In carrying out the atomizing method or the atomizing apparatus of the present invention, it is preferable that the member having a portion having a small cross-sectional area is a cylindrical hollow member. As such a cylindrical hollow member, a thin metal cylindrical member such as an injection needle is suitable.

In implementing the atomizing method or the atomizing apparatus of the present invention, it is preferable that the member having a portion having a minute cross-sectional area has a plurality of straight flow paths. Here, as the member having a plurality of straight flow paths, for example, a bundle of a plurality of small-diameter metal cylindrical members,
Alternatively, it is preferable to adopt a material obtained by sintering the bundled small-diameter metal cylindrical member with a powder alloy, or a member obtained by forming a plurality of through holes by subjecting a solid cylindrical member to electrical discharge machining.

According to the atomizing method and the apparatus of the present invention having the above-described structure, when the material and the fluid to be atomized flow through the chamber member and the member provided with the portion having the small sectional area. Then, ultrasonic vibration is generated by resonance between the chamber member and a portion having a small cross-sectional area and the fluid. That is, when passing through a member having a portion having a small cross-sectional area, vibration corresponding to so-called “flow noise” is generated, and the vibration and the vibration having the resonance frequency of the chamber member are generated in the chamber. Propagate. At this time, since the resonance frequency between the chamber member and the portion having a small cross-sectional area and the fluid is very high, ultrasonic vibration is generated.

When flowing through the chamber member and the member having a portion having a small cross-sectional area, the material (to be atomized) is subjected to bending stress or shearing due to cavitation or collision with a side wall surface. Stress acts. Here, according to the present invention, as a result of the generation of the ultrasonic vibration, the number of repetitions at which the bending stress or the shear stress acts on the material has a large value that cannot be reached by the conventional atomizing apparatus.
Then, the number of repetitions at which a bending stress (bending stress or shear stress caused by cavitation, collision with a side wall surface, or the like) acts on the material to be atomized increases drastically, so that an ideal fine particle for the material is obtained. Is achieved.

In the present invention, by appropriately setting the inner diameter, length, and fluid pressure of the member having a portion having a minute cross-sectional area, the particle size distribution of the atomized object becomes very sharp. The fact that the particle size distribution is very sharp means that the particle size of the atomized object is uniform. In other words, according to the present invention,
This makes it possible to design a particle size which was ideal in the atomization treatment but could not be realized by the conventional technology. That is, by appropriately setting the inner diameter of the member having a portion having a small cross-sectional area and the pressure of the fluid flowing through the member, it is possible to atomize the particles with a predetermined particle size. It should be noted that the particle size distribution becomes sharper if the length of the member having a portion having a small cross-sectional area is increased. That is, accurate particle size design becomes possible.

Here, when the method and apparatus for atomization of the present invention are carried out, the parts which need to be cleaned and come into contact with the atomized material (particles) include the chamber member and a portion having a minute cross-sectional area. Since only the two members are used, the cleaning after the atomization is completed may be performed only on the two members. Therefore, the cleaning property or cleaning efficiency is much higher than the conventional one.

In addition, since the member having the portion having the small cross-sectional area is used as the flow path, it is not necessary to provide many corners or corners. Therefore, there is no risk of stress concentration occurring at the corners or corners, and there is no risk of wear due to the stress concentration.

Further, since the member having the portion having the minute cross-sectional area is an extremely small member as described later, the area (contact surface area) where the member contacts the atomized material is extremely small. Become smaller. Therefore, the cleaning property is improved.

Further, according to the atomization method and apparatus of the present invention, the shape, size, etc. of the member such that ultrasonic vibration is generated by resonance between the chamber member and a portion having a small cross-sectional area and the fluid. By setting the above various parameters, it is no longer necessary to use an ultra-high pressure unlike the conventional atomization apparatus. Therefore, the downsizing of the entire apparatus is promoted very easily.

An ultrasonic vibration generator according to the present invention has a member having a portion having a minute cross-sectional area, and a supply piping system for supplying a fluid to the member, and a member having a portion having a minute cross-sectional area. Is configured to generate ultrasonic vibration by resonance between the portion having the small cross-sectional area and the fluid.
Therefore, by appropriately setting the shape and dimensions of the chamber member and the member having a portion having a small cross-sectional area, the pressure of the fluid passing therethrough, and other various parameters, it is extremely easy to obtain unique ultrasonic vibration. Can be done. At present, the application value of the present invention is extremely high also in the application field of ultrasonic vibration, considering that a piezoelectric element and a high-frequency alternating current are essential for obtaining ultrasonic vibration.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, an apparatus (an atomizing apparatus) for implementing the atomizing method of the present invention is indicated by reference numeral 10 as a whole. The apparatus 10 includes a storage unit 12 to which a material to be atomized and water (fluid) are supplied, a pump 14 of a variable flow rate and a discharge pressure type, and an atomizing member 20 which is a part for atomizing the material. These members are interposed in series in the piping system L1.

A material (for example, oil) to be atomized is supplied from a material supply source 16 to the storage unit 12 via a piping system L2. Further, water as a fluid is supplied from the water supply source 18 through the piping system L3. A supply piping system is configured by the piping systems L1, L2, and L3.

The atomizing member 20 includes a chamber member 22 and
And a metal-made cylindrical hollow member 24 having a small diameter (a member having a portion having a minute cross-sectional area). 1, the cross-sectional area of the chamber member 22 is relatively large. Alternatively, the cross-sectional area of the chamber member 22 is larger than the cross-sectional area of the member 24.

In FIG. 1, reference numeral DD denotes various processing mechanisms that use a mixture of the material and water atomized in the atomizing member 20.

In the embodiment shown in FIG. 1, during the atomization treatment, the material to be atomized is supplied from the material supply source 16 to the storage section 12 via the pipe L2, and the water supply source 18
Supply water from. The material and water supplied to the storage unit 12 are provided with a head by the pump 14 and supplied to the atomization member 20 via the pipe L1.

In the atomizing member 20, the cylindrical hollow member 24 (member having a portion having a small cross-sectional area) is a source of so-called "flow noise" when forming a jet jet. In other words, the cylindrical hollow member 24 acts as a sound source. Further, the resonance frequency of the chamber member 22 and the cylindrical hollow member 24 is very high, and corresponds to the ultrasonic vibration (see the embodiment described later). Therefore, when the cylindrical hollow member 24 acts as a sound source, it resonates with the fluid in the chamber member 22 and the cylindrical hollow member 24 at a frequency as high as ultrasonic vibration. As a result of resonating at a high frequency, the material supplied to the atomizing member 20 has a very large number of times that bending stress or shear stress acts due to collision or cavitation with the wall surfaces inside the members 22, 24 (described later). See Examples). Therefore, very good atomization is achieved.

In the embodiment of FIG. 1, the cylindrical hollow member 24 is shown as a member made of a single thin metal tube. However, as shown in FIG. 2, a plurality of metal-made small-diameter cylindrical hollow members 24A... Bundled by belt members 26 and 26 and a chamber member 22 are combined to form an atomizing member (reference numeral 20A). (Shown).

Alternatively, like the member indicated by reference numeral 24B in FIG. 3, the metal small-diameter cylindrical hollow member 2 shown in FIGS.
A plurality of through holes 28 may be formed in the cylindrical member 27 having a larger diameter than 4, 24A,. Here, when drilling the plurality of through holes 28, it is preferable to use a multi-axis drilling machine.

Here, in FIG. 3, a plurality of through holes 28 are provided.
Are shown as having the same inner diameter, but when atomized substances of a plurality of particle sizes are required, the through holes 28
.. Can be a plurality of different numerical values. For example, if the cylindrical member 27 is made of a high-purity ceramic of alumina, the ceramic has a so-called "open-cell structure", so that there are many pores of about 0.01 mm. If electric discharge machining is performed on the ceramic cylindrical member 27, the inner diameter of the through hole formed by electric discharge machining is about 0.3 mm, so that two types of inner diameter dimensions (0.01 mm and 0.03 mm) are used. Is achieved.

[0034]

FIG. 4 shows an apparatus which models the atomization method and apparatus of the present invention. The atomizing device indicated by the reference numeral 100 is provided with water (fluid) and a material to be atomized (calcium phosphate 10%) through a supply piping system (not shown).
And the dispersant 0.2% pyrrolicisanarium: the inlet particle size is 5.13 μm), a joint J provided on the inlet side I, and three chambers (corresponding to chamber members). C1, C2, C3, two nozzles N1 and N2 interposed between the chambers (corresponding to members having a small cross-sectional area), and an outlet OL for a mixture of atomized material and water (Outflow side O).

The inner diameter d of the nozzles N1 and N2 is 0.2 mm,
The inner diameter D of the chambers C1, C2, and C3 is 7 mm (see FIG. 5). Although not shown, the total length of the nozzles N1 and N2 (the dimension in the direction of the arrow L in FIG. 4) is 0.5.
mm, and the length of the chamber C2 is 20 mm.

[0036] Then, as shown in FIG. 5, the flow velocity of the nozzles N1 and N2 is 64 m / sec, while the flow velocity in the chambers C1, C2 and C3 is 0.05 m / sec, which is obtained from the ratio of the sectional areas. .

Also in this apparatus, good atomization was performed. Assuming that such atomization complies with the conventional cavitation theory, the only place where bending stress or shear stress acts on the particles is at the nozzles N1 and N2. The number of times N in which bending stress or shear stress acts on the particles is obtained by the following equation. N = T / ΔT Expression (1) In this expression (1), T is the time for the particles to pass through the nozzle. If the lengths of the nozzles N1 and N2 are LN and the flow velocity is U, T = LN / U, and the above numerical values are substituted, T = 0.5 × 10 ⁻³ (m) / 64 (m / se
c) On the other hand, ΔT is the cycle of the vibration received by the particles, and corresponds to the reciprocal of the resonance frequency (= 150 KHz). Then, if these numerical values are substituted into the expression (1), N = T / ΔT = (0.5 × 10 ⁻³ / 64) / (1/150 × 10 ³ ) = 1.2 (times) .

Assuming that the atomization of the present invention complies with the conventional cavitation theory, each material particle is sufficiently broken by the bending stress or the shear stress acting only a very small number of 1.2 times on average. It will be atomized. In other words, considering that the number of times N = 1.2 times is a value that is extremely small as the number required for atomizing the particles, the atomization of the present invention is performed according to the conventional cavitation theory. I have to judge that it is not a thing.

On the other hand, when the atomization according to the present invention is assumed to be due to the generation of ultrasonic vibrations due to the resonance between the chamber member and the portion having a small cross-sectional area and the fluid, the number of times N is calculated. Try. When the apparatus of FIG. 4 is applied to such a model, it can be considered that a combination of an apparatus including the chamber C1 and the nozzle N1 and an apparatus including the chamber C2 and the nozzles N1 and N2.

As described above, the length of the chamber C2 (FIG. 4)
(L dimension in the direction of arrow L) LC is 0.02 m and the representative speed is 1500 m / sec as the sound speed, the basic frequency F is F = 1.
500 / 0.02 = 75 KHz. The frequency at which resonance occurs in both of the two devices (the device including the chamber C1 and the nozzle N1 and the device including the chamber C2 and the nozzles N1 and N2) is 2F = 150 KH.
z (harmonic frequency). Therefore, resonance frequency 150K
Hz, the number N of times that a bending stress or a shear stress acts on the particles in the chamber C2 is expressed by the following equation (1): N = T / ΔT The time T (= LC / U:
However, when the length of the chamber C2 is LC and the flow rate is U, the flow rate in the chamber C2 is 0.05 m / sec (see FIG. 5), so that T = 20.0 × 10 ⁻³ (m) / 0. .05 (m /
sec). On the other hand, the period ΔT of the vibration received by the particles
Is the reciprocal of the resonance frequency of 150 KHz. By substituting these numerical values into equation (1), N = T / ΔT = (20.0 × 10 ⁻³ /0.05)/(1/150×10 ³ ) = 6 × 10 ⁴ (times) Become. This number is a numerical value sufficient to achieve good atomization. Therefore, it can be understood from this embodiment that the present invention is atomization based on acoustic effects or resonance.

Further, the particle size distribution of the material atomized by the present invention becomes sharper than in the prior art, and the above-mentioned conclusion that the number of times bending stress or shear stress acts on the particles is extremely large. And agree well.

[0042]

Second Embodiment Using the atomizing apparatus shown in FIG. 1, an experiment of mixing or emulsifying oil (20%) and water (80%) was performed. Here, the metal-made cylindrical hollow member 24 having a small diameter (a member having a portion having a small cross-sectional area) has a length of 2 mm.
An injection needle having a diameter of 5 mm and an inner diameter of 0.5 mm was used. In addition, as shown in FIG. 6, the tip portion 24E of the injection needle was disposed such that the inclined portion 30 was directed downward.

After setting the discharge pressure of the pump 14 (see FIG. 1) to 10 atm and performing a stirring operation for 3 seconds and a circulation operation for 3 seconds, a laser diffraction / scattering type particle size distribution measuring apparatus (Horiba in the embodiment) FIG. 7 shows the result of measurement using a product name “LA-910” manufactured by Mfg. Co., Ltd .: the particle size distribution measuring device is not shown).

The measurement results shown in FIG. 7 show that the finely divided particles have a very sharp particle size distribution substantially in the normal distribution centering around 3 to 5 μm, and that the finely divided particles can be performed very well. It has been shown.

[0045]

Third Example A sample similar to that of the second example was subjected to the same measurement as that of the second example using an experimental apparatus similar to that of the second example. However, the pressure is 1 atm, the dispersion time is 1 minute, the inner diameter of the injection needle is 1.2 mm, and the length is 3
8 mm. FIG. 8 shows the measurement results. It can be seen that the particle size of the atomized sample has two types of peaks which are normally distributed and very sharp.

FIG. 9 shows the results obtained when the pressure was set to 3 atm under the same conditions as the measurement results shown in FIG.
FIG. 10 shows the result when the pressure is set to the atmospheric pressure. In the cases shown in FIGS. 8 to 10, the pressure of the sample and the fluid supplied to the atomization device affects the particle size or the particle size distribution.

[0047]

Fourth Embodiment FIG. 11 shows the measurement results when the pressure is 60 kgf / cm ² using a syringe needle having an inner diameter of 0.55 mm and a length of 25 mm in the same manner as in the second embodiment except for the pressure. , in Figure 12 the measurement results when the pressure 70 kgf / cm ^2, Figure 13 a measurement result in the case of a pressure 90 kgf / cm ^2, respectively show.

In this case, the pressure has little influence on the particle size or the particle size distribution. However, it is understood that in each case, a very sharp particle size distribution is shown.

[0049]

Fifth Embodiment FIG. 14 shows the experimental results when titanium oxide was used as a sample. As in the case of oil, very good atomization is achieved and the particle size distribution is very sharp.

[0050]

The effects of the present invention are listed below. (1) The particle size distribution is very sharp and good atomization is achieved. (2) An atomization method and apparatus based on a completely new principle that takes into account not only the occurrence of cavitation as in the related art but also an acoustic effect or a resonance effect are provided. (3) The particle size can be designed. (4) The cleaning property or cleaning efficiency is improved. (5) The area (contact surface area) of the member in contact with the atomized material can be made extremely small, and the labor required for cleaning can be reduced. (6) The downsizing of the entire device is promoted very easily. (7) Since there is no need to use an ultra-high pressure machine or expensive materials such as diamond, the manufacturing cost can be extremely low. (8) By appropriately setting the shape, dimensions, and other various parameters, ultrasonic vibration can be obtained extremely easily without requiring a piezoelectric element or a high-frequency alternating current. (9) It can be used in a wide range of fields such as dispersion, emulsification, mixing, stirring, crushing, etc., and has extremely good versatility.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a member having a portion having a small cross-sectional area, which is different from FIG.

FIG. 3 is a perspective view of a member provided with a portion having a small cross-sectional area, which is different from FIGS. 1 and 2;

FIG. 4 is a block diagram showing a model of the apparatus according to the first embodiment of the present invention.

FIG. 5 is a table showing numerical values relating to various flow paths formed in the apparatus of FIG. 4;

FIG. 6 is a side view illustrating a member (injection needle) having a portion having a small cross-sectional area used in a second embodiment of the present invention.

FIG. 7 is a diagram showing a measurement result of a second embodiment of the present invention as a particle size distribution.

FIG. 8 is a diagram showing a measurement result of one embodiment of the third embodiment of the present invention as a particle size distribution.

FIG. 9 is a diagram showing a measurement result according to another aspect of the third embodiment of the present invention as a particle size distribution.

FIG. 10 is a diagram showing a measurement result of still another mode of the third embodiment of the present invention as a particle size distribution.

FIG. 11 is a diagram showing a measurement result of one embodiment of the fourth embodiment of the present invention as a particle size distribution.

FIG. 12 is a diagram showing a measurement result of another aspect of the fourth embodiment of the present invention as a particle size distribution.

FIG. 13 is a view showing a measurement result of still another mode of the fourth embodiment of the present invention as a particle size distribution.

FIG. 14 is a diagram showing a measurement result of a fifth embodiment of the present invention as a particle size distribution.

[Explanation of symbols]

10, 100 ... atomization device 12 ... storage part 14 ... pump 16 ... material supply source 18 ... water supply source 20, 20A ... atomization member L1, L2, L3 ...・ Piping (supply piping system) 22 ・ ・ ・ Chamber member 24, 24A, 24B ・ ・ ・ Member with a portion having a small cross-sectional area D ・ ・ ・ Various treatments using a mixture of atomized material and water Mechanism 26 ... Belt member 28 ... Through hole I ... Inflow side J ... Joint part C1, C2, C3 ... Chamber N1, N2 ... Nozzle OL ... Outlet O ...・ Outflow side

Claims (7)

[Claims] 1. A method for atomizing a material to be atomized by mixing the material to be atomized with a fluid, wherein the material and the fluid to be atomized have a small cross-sectional area via a chamber member having a relatively large cross-sectional area. Having a step of flowing through a member having a portion, and in this step, ultrasonic vibration is generated by resonance between the chamber member and a portion having a small cross-sectional area and the fluid, and the material to be atomized is An atomizing method characterized by repeatedly applying stress. 2. The atomization method according to claim 1, wherein said member having a portion having a minute cross-sectional area is a cylindrical hollow member. 3. The atomization method according to claim 1, wherein the member having a portion having a minute cross-sectional area has a plurality of straight flow paths. 4. An atomization apparatus for atomizing a material to be atomized by mixing with a fluid, wherein a chamber member having a relatively large cross-sectional area, a member having a portion having a small cross-sectional area, and said atomizing means. A supply piping system for supplying a material and a fluid to be supplied to the chamber member and a member having a portion having a small cross-sectional area, wherein the member having the chamber member and the portion having a small cross-sectional area is atomized. An atomizing apparatus characterized in that ultrasonic vibration is generated by resonance between the chamber member and a portion having a small cross-sectional area and the fluid in order to repeatedly apply a stress to a material to be formed. . 5. The atomization apparatus according to claim 4, wherein said member having a portion having a minute cross-sectional area is a cylindrical hollow member. 6. The atomizing apparatus according to claim 4, wherein said member having a portion having a minute cross-sectional area has a plurality of straight flow paths. 7. A chamber member having a relatively large cross-sectional area, a member having a portion having a small cross-sectional area, and a supply piping system for supplying a fluid to the chamber member and a member having a portion having a small cross-sectional area. Wherein the member having the chamber member and the portion having a small cross-sectional area is configured to generate ultrasonic vibration by resonance of the fluid with the chamber member and the portion having a small cross-sectional area. An ultrasonic vibration generator, comprising: