JPH0468972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method and apparatus for air mixing powder,
In particular, the present invention relates to a method and an apparatus for continuously mixing powder without destroying powder particles by applying the principle of collecting powder using a cyclone.

Prior Art The mixing operation for mixing two or more types of powder to produce a homogeneous product is complex in nature, and the basic theory thereof has not yet been sufficiently established.

Mixers mainly include rotary mixers in which the mixing container itself rotates, and fixed mixers in which the mixing container is fixed and blades inserted into the container are rotated. The former, as shown in FIGS. 1 and 2, rotates a cylindrical container 100 or an upright cubic container 101, and the mixing speed is fast, but the powder heats up and changes in quality due to collisions between particles. There is a risk. Moreover, since it is a batch method, continuous processing is not possible.
The latter fixed type mixer, as shown in FIGS. 3 and 4, has a screw 103 inside a mixing container 102.
104, and is excellent in that it can process even wet powder and cohesive powder. However, since the powder is mixed by kneading, there is a risk that the powder will generate heat and deteriorate in quality. Moreover, since it is a batch process, it can only be processed intermittently. As shown in FIG. 5, a fixed type mixer is also known as an air flow type mixer that blows gas from below to above a container 105 to mix powder. Because turbulence occurs inside the machine, there is a risk that the powder particles will collide with each other and be destroyed. Moreover, since it is a batch method, continuous processing is not possible.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method and apparatus for air-flow mixing of powders, which minimizes collisions between powders and allows continuous operation. Another object of the present invention is to provide a mixing method and apparatus in which the powder is cooled and does not generate heat because a gas flow such as air is used as the mixing medium.

Summary of the Invention The present invention utilizes the principle of a cyclone, which generates a rotating airflow inside the machine and uses centrifugal force to obtain a sedimentation velocity several hundred to several thousand times that of gravity, and which can collect particles even several micrometers in size. The invention was completed based on the inventor's knowledge that multiple types of powder can be mixed homogeneously. Therefore, the powder mixing method of the present invention includes (1) a step of introducing various powders to be mixed into a spiral airflow, and (2) a step of introducing powder-containing gas into a cylindrical region from multiple directions at a predetermined speed. A step of blowing from the tangential direction to form a multilayer rotating flow descending into the cylindrical region, (3) turning the rotating flow into a centripetal rotating flow in the conical region below the cylindrical region, thereby causing the gas to gradually rise in the vicinity of the center. and (4) the step of causing the powder to settle downward under its own weight and being discharged from the bottom of the conical region out of the system and collected, thereby achieving the above purpose. . The powder mixing device of the present invention is intended to embody this mixing method, and includes a spiral airflow generating means, an inlet into which the powder to be mixed can be inputted, and an inlet located in front of the inlet to inject the powder. a cylinder having a spiral airflow outlet containing the cylinder; a cyclone cylinder part provided tangentially to the cylinder; a gas discharge pipe provided at the center of the interior of the cyclone cylinder part; connected to a lower part of the cyclone cylinder part; A spiral flow of gas containing the powder is blown into the cyclone cylinder at a predetermined speed, forming a descending multilayer rotating flow within the cyclone cylinder, and a centripetal flow within the cone. As a result, the gas gradually changes to an upward flow near the center and is discharged from the system through the gas discharge pipe above, and the powder settles downward and is collected from the bottom of the cone, thereby achieving the above purpose. is achieved.

Example The present invention will be described below with reference to examples.

As shown in FIGS. 6, 7, and 8, the mixing device 1 of the present invention has a cyclone cylindrical portion 11 and a conical portion 12 connected to the cyclone cylindrical portion 11 and located below the cyclone cylindrical portion 11. . This conical part 1
2 has an inner diameter that becomes smaller toward the bottom, and a powder collection port 120 is formed at the lower end. This collection port 12
0 is provided with an air pressure adjusting means 121 such as a rotary valve as necessary. A cylinder 13 is attached to the upper part of the cyclone cylinder part 11 along the tangential direction thereof. This cylinder 13 has a multilayer spiral airflow generating means 1 such as a fan or screw inside.
31 are provided. In front of this spiral airflow generating means 131 is an inlet 13 for each powder to be mixed.
0 is set. The front end of this cylinder 13 forms a spiral airflow outlet 132 and communicates with the cyclone cylinder section 11 . Spiral airflow generating means 13
1 is not limited to the above-mentioned fan or screw. For example, a helix 140 can be provided on the inner wall of the cylinder 13 to generate the necessary multilayer spiral airflow. A gas discharge pipe 14 is provided at the center of the cyclone cylinder part 11.

Using this device, a plurality of types of powder are homogeneously mixed in the following manner: First, gas such as air is introduced into the cylinder 13 from behind the spiral airflow generating means 131.
supplied within. At this time, if there is no obstruction in the cylinder, the flow can be rectified. This rectification is caused by the spiral airflow generating means 131 to become a multi-layered spiral airflow within the cylinder 13 and directed toward the discharge port 132 at the front of the cylinder. During this time, each powder to be mixed is fed into the multilayer spiral air stream in fixed amounts from the inlet 130. A spiral airflow containing powder is blown into the cyclone cylinder part 11 from the outlet 132. Powders are usually introduced into the gas in the form of primary particles. The multilayer spiral airflow forms a multilayer rotational flow within the cyclone cylindrical portion 11 and heads toward the conical portion 12 below while rotating. This rotating airflow then becomes a centripetally rotating flow within the conical portion 12, and the gas gradually turns into an upward flow near the center. The gas then exits out of the system through the gas discharge pipe 14 of the cyclone cylindrical portion 11. In the cyclone cylindrical part 11, in which the gas descends while rotating, and in the conical part 12, which has a centripetally rotating flow, the powder particles in the gas are subjected to the same action as in a centrifugal separator or dry centrifugal classifier, and are separated from the walls. It settles in the opposite direction, descends on the inner surface of the conical part, and is taken out of the system through the collection port 120. The obtained powder is a homogeneous mixture of various powders before operation. This device usually
Powders in the particle range of 2.0 to 200 μm can be processed.
The collection efficiency depends on the ratio between the axial length of the conical portion 12 and the diameter of the collection port 120. Collection port 12
0, air pressure adjustment means 121 such as a rotary valve
By providing this, air pressure fluctuations within the device 1 are kept to a minimum, so that the multilayer rotating flow within the device 1 is not disturbed.

Effects of the Invention According to the present invention, since a multilayer spiral airflow containing various powders is introduced into the cyclone, collisions between powder particles are reduced. Therefore, the powder can be mixed homogeneously without changing its quality. Moreover, communication operations are possible.

[Brief explanation of the drawing]

1 to 5 are schematic explanatory diagrams showing a conventional mixer, FIG. 6 is a cross-sectional front view showing an example of the powder supply cylinder of the device of the present invention, and FIGS. 7 and 8 are respectively in accordance with the present invention. 1 is a perspective view and a partially sectional front view showing an embodiment of the invention device 1. FIG. DESCRIPTION OF SYMBOLS 1... Mixing device of the present invention, 11... Cyclone cylindrical part, 12... Cone part, 13... Cylinder, 14... Gas discharge pipe, 120... Collection port, 121... Air pressure adjustment means, 1
30... Powder inlet, 131... Multilayer spiral airflow generator, 132... Spiral airflow outlet.

Claims (1)

[Claims] 1. (1) A step of introducing various powders to be mixed into the spiral airflow; (2) A step of blowing the spiral airflow containing the powder into a cylindrical region from a tangential direction at a predetermined speed; (3) forming a multilayer rotating flow descending within the cylindrical region; A method for mixing powder with air flow, which includes the steps of: discharging the powder from above the conical region; and (4) allowing the powder to settle downward under its own weight, and discharging the powder from below the conical region to the outside of the system and collecting it. 2. A cylinder equipped with a spiral airflow generating means, an inlet into which powder to be mixed can be inputted, and a spiral airflow outlet located in front of the inlet and containing the powder; A cyclone cylindrical part provided; a gas discharge pipe provided at the center of the cyclone cylindrical part; and a conical part connected to the lower part of the cyclone cylindrical part, the spiral air flow of gas containing the powder is The gas is blown into the cyclone cylinder at a predetermined speed, becomes a multilayer rotating flow that descends within the cyclone cylinder, and becomes a centripetally rotating flow within the cone, whereby the gas gradually turns into an upward flow near the center, and the gas above An air flow mixing device for powder in which the powder is discharged from the system through a discharge pipe, settles downward, and is collected from the lower part of the cone. 3. The device according to claim 2, wherein an air pressure adjustment means is provided at the powder collection port of the conical part.