JPH0554376B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention makes it possible to uniformly disperse powder or granular material by swirling the dispersion airflow of powder or granular material made of powder. This invention relates to a method for dispersing powder and granular materials. More specifically, an obstacle is disposed inside a swirling nozzle that swirls a dispersion airflow of powder and granules, and the obstacle moves the powder and granules swirling along the inner wall of the swirling nozzle toward the inside of the swirling nozzle. This invention relates to a method for dispersing powder and granular material that can obtain a high shear force and separate the powder and granular material into individual primary particles, and furthermore, can disperse the powder and granular material uniformly. .

[Conventional technology]

Conventionally, methods for dispersing powder or granules include (1) dispersing the powder using an ejector, feeding it to a cyclone via a distributor, and dispersing it from the bottom of the cyclone; (2) A method in which powder and granules are discharged together with a small amount of air to disperse them (see Japanese Patent Laid-Open No. 101951/1983). (3) A method in which the dispersion airflow from the ejector is discharged from a spray pipe having a dispersion rectifier plate at the opening. 166860), (4) A method in which a dispersion airflow of powder particles is swirled in a swirling chamber and then discharged from a swirling nozzle in an empty conical shape (see Japanese Patent Application Laid-Open No. 196728), etc. Various methods are known.

[Problem that the invention seeks to solve]

However, in the method (1) above, it is not possible to obtain a large shearing force, so it is not possible to disperse particles with strong cohesiveness or adhesion. Since the particles are discharged while swirling more, the concentration of the powder particles in the central part of the discharge stream becomes thinner, resulting in a large deviation in the concentration, which poses the problem that uniform dispersion cannot be achieved. Also, in the method (2) above,
Since the powder is discharged from a nozzle having a spiral passage while rotating, the concentration of the powder in the center of the discharge stream becomes thinner, resulting in a large concentration imbalance and the problem that uniform dispersion cannot be achieved. are doing. In addition, in method (3) above, the velocity in the spray tube is maximum at the center and rapidly decreases toward the periphery, so the dispersed airflow is discharged without spreading, and is therefore dispersed by the dispersion rectifier plate. Even if it is, the concentration tends to be uneven and it is difficult to disperse it uniformly. Moreover, when discharging a dispersed airflow of powder or granular material in a high-temperature atmosphere, since the dispersion rectifier plate is placed outside the spray pipe, the powder or granule material may be thermally fused to the dispersion rectifier plate, making it difficult to operate properly. It has the problem of not being able to be dispersed. Also, (4) above
In the above method, since the air stream for dispersing the powder particles is discharged in an empty conical shape, the concentration of the powder particles in the center of the discharge stream becomes thinner, and there is a problem that uniform dispersion cannot be achieved.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its purpose is to avoid the above-mentioned problems and to enable fine dispersion of powder and granules into individual particles without bias. An object of the present invention is to provide a method for dispersing powder and granular materials.

[Means for solving problems]

The method for dispersing powder and granular material of the present invention involves supplying the powder and granular material to an ejector and introducing a compressed air flow, thereby introducing the resulting dispersion airflow of the powder and granular material into a cylindrical rotating nozzle having an axis extending in the vertical direction. Then, the dispersion airflow of the powder and granular material is made to descend while swirling along the inner wall of the swirling nozzle, and the swirling powder and granular material is disposed inside the swirling nozzle at a midway point in the axial direction. The present invention is characterized in that an obstacle is disposed inwardly in the radial direction of the nozzle, and the dispersed airflow of the powder particles that has passed through the obstacle is discharged from the lower end outlet of the swirling nozzle.

According to this method, the airflow for dispersing powder and granules is swirled inside the swirling nozzle, so that the powder and granules are subjected to high shearing force and are dispersed into individual particles, and the swirling causes them to spread onto the inner wall of the swirling nozzle. Since the dispersion airflow flowing in a layered manner is also diffused inward by obstacles, the powder and granules are discharged from the rotating nozzle in a well-dispersed state in the form of individual particles without bias. Therefore, even in a high-temperature atmosphere, for example, the powder or granules will not be thermally fused to obstacles, and the powder or granules will not stick together, resulting in a good dispersion state.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram schematically showing an example of a dispersion device that can be used to carry out the present invention, in which 1 is a compressed air flow inlet, 2 is a powder supply port,
3 is the ejector mixing chamber, 4 is the ejector throat section,
5 is a swirling chamber, 6 is a swirling nozzle, and 7 is an obstacle. As shown in FIG. 2, the rotating nozzle 6 has a cylindrical shape with an axis extending in the vertical direction, and has an opening at the lower end. In addition, the obstacle 7
is made up of a plurality of blades 71, and each blade 71 is directed inward from the inner wall of the swirl nozzle 6 in the axial direction midway inside the swirl nozzle 6, and also toward the downstream direction of the swirl of the dispersed air flow. It is fixed to the inner wall of the rotating nozzle 6 so as to protrude diagonally and extend along the axial direction of the rotating nozzle 6 . In this example, a total of four blades 71 are provided, and these four blades 71 are arranged at approximately symmetrical positions with respect to the axial direction of the rotating nozzle 6. The specific shape of each blade 71 is not particularly limited, and may be, for example, triangular, rectangular, trapezoidal, other polygonal shapes, or curved. Further, the number of blades 71 to be arranged is not particularly limited, and may be one or more.

In the present invention, a compressed air flow is introduced into the ejector mixing chamber 3 from the compressed air flow introduction port 1, and powder and granular material is supplied into the ejector mixing chamber 3 from the supply port 2, thereby creating a high-pressure system in which the powder and granular material is dispersed. Airflow is introduced into the swirling chamber 5 via the ejector throat section 4. In the swirling chamber 5, the high-pressure dispersion airflow of powder and granular material is swirled, and the pressure causes the swirling dispersion airflow to descend along the inner wall of the swirling nozzle 6. Inside the swirling nozzle 6, the dispersion airflow descending while swirling along the inner wall of the swirling nozzle 6 collides with the surface of the obstacle 7, that is, the blade 71, thereby changing its direction and causing the flow to flow inside the swirling nozzle 6. The dispersed air stream is discharged downward from the outlet formed by the opening at the lower end of the swirling nozzle 6 while diffusing the dispersed air stream in the opposite direction.

According to the above embodiment, the dispersion airflow of the powder particles moving downward while swirling in a layered manner along the inner wall of the swirling nozzle 6 collides with the blades 71 so that the flow is directed inward. As a result, as shown by the arrows in FIG. 2, multiple small vortices are generated, and some powder and granules move towards the center of the rotating nozzle 6, while others move towards the center of the rotating nozzle 6 due to centrifugal force.
The radial direction (X direction) of the nozzle 6 rotates toward the inner wall of the
will be spread evenly. Therefore, from the opening of the swirling nozzle 6, the thickness D of the empty conical swirling airflow layer increases, and the spatial concentration of the powder in the dispersed airflow is low, and the powder in the radial direction (X direction) of the swirling nozzle 6 increases. The dispersion airflow of the powder particles is discharged downward in a state where the particle concentration becomes substantially uniform. As a result, the powder is separated into primary particles without agglomeration, and the powder and granule concentration is uniform in the compressed air flow introduced into the ejector mixing chamber 3. The particles can be dispersed well. Since the obstacle 7 is disposed inside the rotating nozzle 6, there is no possibility that the powder or granules will be thermally fused to the obstacle 7 in a high-temperature atmosphere. It is particularly suitable for such cases.

FIG. 3 is an explanatory diagram schematically showing still another example of a dispersion device that can be used to carry out the present invention. This is an example. This narrowed portion 72 has a small diameter through hole 73 in the center.
and a conical expansion surface 7 that expands diagonally upward and diagonally downward from the through hole 73, respectively.
4 and 75. In this example, the dispersed airflow of powder particles moving downward while swirling in a layered manner along the inner wall of the swirling nozzle 6 is temporarily collected by the small-diameter through-hole 73 in the center, and then exits from the through-hole 73. By discharging the dispersion airflow so as to spread along the lower expanding surface 75, the dispersion airflow can be well diffused in the radial direction (X direction) of the swirling nozzle 6, and as a result, the powder particles agglomerate together. It is possible to disperse the powder and granules well in a state where they are separated into single particles without being accompanied by particles and in a state where the concentration of the powder or granules is uniform.

FIG. 5 is a schematic explanatory diagram of still another example of a dispersion device that can be used to carry out the present invention, and in this example, the inside diameter is an enlarged tapered shape that widens as it goes downward. This is an example in which a rotating nozzle 61 is provided, and a blade 71 is provided as an obstacle 7 similar to that shown in FIGS. 1 and 2.
In this example, since the rotating nozzle 61 has an enlarged tapered shape and has a large opening, the powder can be discharged in a state where it is widely spread in the radial direction (X direction) of the rotating nozzle 61. Therefore, in a large area, 1
The powder can be well dispersed in a state in which it is separated into secondary particles and in a state in which the powder or granule concentration is uniform, and it is suitable when such a large dispersion area is required.

FIG. 6 is an explanatory diagram showing the outline of still another example of a dispersing device that can be used to carry out the present invention, and in this example, the inner diameter is a tapered shape that decreases as the inner diameter becomes smaller. This is an example in which a rotating nozzle 62 is provided, and a blade 71 similar to that shown in FIGS. 1 and 2 is provided as an obstacle 7. In this example, since the rotating nozzle 62 has a reduced taper shape and has a smaller opening,
The powder and granules can be discharged in a small agglomerated state in the radial direction (X direction) of the rotating nozzle 62, and therefore the powder and granules are separated into primary particles in a small area without agglomeration. Moreover, the powder and granules can be dispersed well with a uniform powder and granule concentration, and is suitable when such a small dispersion area is required.

〔Effect of the invention〕

As described above, the present invention supplies powder and granular material to an ejector and introduces a compressed airflow to disperse the powder and granular material into a cylindrical rotating nozzle having an axis extending in the vertical direction. , the dispersion airflow of the powder and granular material is caused to descend while swirling along the inner wall of the swirling nozzle, and inside the swirling nozzle,
An obstacle is placed in the middle of the axial direction to diffuse the swirling powder and granules inward in the radial direction of the rotating nozzle, and the dispersed airflow of the powder and granules that has passed through this obstacle is swirled. Since this method of dispersing powder and granules is characterized by discharging the powder from the lower end outlet of the nozzle, the dispersion airflow of the powder and granules is swirled inside the swirling nozzle, so that the powder and granules are subjected to high shearing force and separated into individual particles. In addition to being dispersed in the form of particles, the dispersed airflow that flows in a layered manner on the inner wall of the rotating nozzle due to swirling is also diffused inward due to obstacles, so that the powder and granules are The liquid is discharged from the rotating nozzle in a uniformly dispersed state in the form of individual particles. Therefore, even in a high-temperature atmosphere, for example, the powder or granules will not be thermally fused to obstacles, and the powder or granules will not stick together, resulting in a good dispersion state.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing an example of an apparatus that can be used in the method of the present invention, FIG. 2 is a schematic explanatory diagram of the apparatus shown in FIG. 1 viewed from below, and FIG. FIG. 4 is a schematic explanatory diagram of another example of the apparatus that can be used in the method of the invention; FIG. 4 is a schematic explanatory diagram of the apparatus shown in FIG. 3 when viewed from below;
6 and 6 are explanatory diagrams each schematically showing still another example of the apparatus that can be used in the method of the present invention. DESCRIPTION OF SYMBOLS 1... Compressed air flow inlet, 2... Powder supply port, 3... Ejector mixing chamber, 4... Ejector strobe section, 5... Turning chamber, 6... Turning nozzle, 7
... Obstacle, 61 ... Swivel nozzle, 62 ... Swivel nozzle, 71 ... Vane, 72 ... Constriction, 73 ...
...Through hole, 74, 75... Expansion surface.

Claims (1)

[Claims] 1 The dispersed airflow of the powder and granular material obtained by supplying the powder and granular material to the ejector and introducing a compressed airflow is introduced into a cylindrical swirling nozzle having an axis extending in the vertical direction. Then, the dispersion airflow of the powder and granular material is made to descend while swirling, and the swirling powder and granular material is diffused inward in the radial direction of the swirling nozzle at a midway point in the axial direction inside the swirling nozzle. A method for dispersing powder or granular material, characterized in that an obstacle is provided and a dispersion airflow of the powder or granular material that has passed through the obstacle is discharged from a lower end outlet of a swirling nozzle.