JPH07256076A - Powder mixing device - Google Patents

Abstract

PURPOSE:To efficiently mix a powder with a high productivity by partitioning the interior of a hermetically closed rotary container rotated around the central horizontal axis thereof at a low speed by at least one screen part capable of permitting a powder to pass provided so as to be positioned in the plane containing the horizontal axis parallel to the center of rotation of the container. CONSTITUTION:In a powder mixing device wherein a powder (a) is mixed in a hermetically closed rotary container 1 rotated around the central rotary horizontal axis A thereof at a low speed, the interior of the rotary container 1 is partitioned at the central part thereof by at least one screen part 7 capable of permitting a powder (a) to be positioned within the plane containing the horizontal axis parallel to the center of rotation thereof. As a result, since the powder and air can be mixed in one hermetically closed rotary container while circulated repeatedly, it is unnecessary to supply compressed air into the container from the outside and a special means for separating the powder and air is not required. The powder can be mixed without being affected by a raw material compsn. or ratio, a particle size, a form or distribution specific gravity difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder mixing apparatus applicable to various industrial fields such as the ceramic industry, food industry, chemical industry and plastic industry.

[0002]

2. Description of the Related Art Uniform mixing of powders is difficult except in special cases, and the process is complicated and costly. This is because the powder has a larger surface area than the volume, and adjacent particles tend to agglomerate, which hinders uniform mixing. By the way, the degree of agglomeration depends on the raw material composition and ratio of the powder, the particle size, the morphology of the crushed particles, the degree of coarse crushing and the particle size distribution, and the manufacturing method of the powder (for example, mechanical crushing is abrasion crushing). And impact pulverization is different in the degree of disorder of the structure of the particle surface) and so on.

When the powders are mixed uniformly on an industrial scale,
It is necessary to take measures to prevent the powder from agglomerating, and typical examples currently implemented are as follows (1) to (3).

(1) A method in which powder and gas are simultaneously supplied into a container and once dispersed in an air stream to weaken the cohesive force and to disperse and mix in the air stream.

(2) Powder, additives, hard balls, etc. are placed in a container and the container is rotated to mix. Or, a method of mixing by rotating a stirring blade in a fixed container.

(3) A method in which the powder is made into a slurry in water to weaken the cohesive force between the particles and to mix the water and the particles together.

Specific examples of the mixing method (1) include the following (a) to (e).

(A) Japanese Patent Laid-Open No. 55-88834 Japanese Patent Laid-Open No. 55-88834: Powder and atmospheric flow are simultaneously charged, and the spiral blade in the container is rotated by the atmospheric flow so that the powder collides with the blade. A method in which the powder and the air stream are discharged simultaneously from the discharge port on the top by mixing.

(B) JP-A-60-161721, 16
No. 1722 The powder and the air flow are supplied to the No. 1722 container through the inlet having the spiral air flow generation device, and the air flow is adjusted depending on the shape of the cyclone container. A method of discharging the powder from the discharge port and collecting the powder from the lower part.

(C) Japanese Patent Laid-Open No. 1-159039 A gas is supplied from the lower part to float and mix the powder, and the powder is collected by a bag filter of a dust collector connected to a discharge port on the upper part. The gas flow is discharged by a fan.

(D) Japanese Unexamined Patent Publication (Kokai) No. 2-157033 A powder is dispersed and mixed by a stirring blade which is rotated around a central axis of a vertical cylindrical shape, a stirring blade in a lowering portion and pressure air from the lower portion. A method of simultaneously discharging powder and air flow from the upper part.

(E) Japanese Unexamined Patent Publication No. 2-251254 By a stirring blade which is rotated around a central axis of a vertical cylindrical shape, a stirring ball which is rotatably flown by the stirring blade in the lower portion, and pressure air from the lower portion. , A method in which the powder is dispersed and mixed, and the powder and the air stream are simultaneously discharged from the upper part.

What is common to (a) to (e) is that the powder is forcibly dispersed by externally supplying an air flow into the container in order to weaken the cohesive force of the powder. After the completion of the mixing work, a huge amount of powder and gas must be conveyed to the next step to separate the powder from the gas, which causes the following problems.

A. A device for supplying air, gas, etc. is required, and the equipment is complicated and expensive.

B. Powder and gas separation devices such as bag filters, cyclones, and various air cleaning devices are required, which makes equipment complicated and expensive, and also requires a large installation area.

C. Since the powder is discharged together with the gasified gas, the powder having a low specific gravity affects the morphology and distribution of the particles, and uniform mixing is difficult.

D. Since the mixing is performed by the air flow in the container, even if the mixing is insufficient, the powder is continuously discharged to the next step together with the air flow, and the mixing is insufficient.

E. Since the time required until the powder is supplied into the container and discharged is the mixing time (passing method), it is difficult to uniformly mix the powder. That is, it is necessary to increase the size of equipment such as a container to prolong the mixing time (the time for powder to pass through the container must be prolonged).

The mixing method (2) is called a ball mill type, a drum type or the like, and the production of cement can be mentioned as a typical example. In this method, the powder is mechanically forcibly mixed in the agglomerated state,
It is necessary to mix the powder with water, a solvent, and an additive for several hours, which takes time, resulting in a high production cost.

Regarding the method (3) of dispersing the powder in water and mixing it, there is a spray dryer method or the like as a method mainly used for mass production in tile production. This spray dryer method is a method in which powder is dispersed in slurry such as water to form a slurry, sprayed and atomized from the top and dropped, and the hot air supplied from the bottom, etc. is used during this drop to mix. And there is an advantage that granulation can be performed at the same time. However, this method requires a large amount of heat energy to evaporate water, and its processing capacity is low, but the cost is high.

Further, the powder can be uniformly mixed by dispersing and mixing it in water, but in the next step, the water is removed by a filter press, dried, crushed, pelletized and used through a sieving machine. There are problems such as large area equipment, complicated equipment and high installation cost.

The present invention has been made for the purpose of eliminating such conventional problems.

[0023]

SUMMARY OF THE INVENTION The present invention is an apparatus for mixing powder in a hermetically-sealed rotary container that rotates at a low speed with a horizontal axis as the center of rotation. Is separated by a sieving part capable of passing through, and the sieving part is installed in at least one stage so as to be located in a plane including a horizontal axis parallel to the center of rotation. Pertain.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the mixing apparatus of the present invention is provided with a sealed rotary container 1 which rotates about the horizontal axis.

The shape of the rotary container 1 is preferably a line-symmetrical shape with respect to the horizontal axis passing through the center in the side surface shape shown in FIG. 1, and a vertical cylindrical shape is shown in the figure. In addition, it may have a horizontal tubular shape or a spherical shape.

The rotary container 1 needs to be rotated about the horizontal axis, and in FIGS. 1 and 2, the rotary container 1 is rotated about the horizontal axis passing through the center of the rotary container 1. Although shown, the center of rotation may be off the center of the rotary container 1.

The rotary container 1 shown in FIG. 1 is supported on the upper end of the pedestal 3a of the leg base 3 via bearings 4 and 4 on a horizontal rotary shaft 2 extending outward from one side of the container 1. In this supporting state, the drive device 5 is operated to be rotated via the transmission mechanism 6.

A sieving portion 7 is installed in the center of the rotary container 1 so as to be located in a plane including the horizontal axis. The sieving portion 7 allows the interior of the rotary container 1 to have one chamber 1A and the other chamber. It is divided into 1B. The number of installation stages of the sieving unit 7 is one as shown in FIGS. 1 and 2, and FIG.
There are cases where there are multiple stages, as schematically shown in
In the case of a plurality of stages, each stage is parallel and a space 8 is provided between them. The interval 8 is necessary for preventing clogging of the powder between the sieving portions 7, 7 of each stage.

The sieving portion 7 needs to have a mesh that allows the raw material powders mixed in the rotary container 1 to freely pass therethrough, and usually varies depending on the particle size distribution of the powders, etc. It is appropriately selected and determined from the range of about 1 to 50 mesh. When the sieving portions 7 are installed in a plurality of stages, the size of the mesh of the sieve may be changed for each stage. Sieve 7
Are detachably installed and fixed in the rotary container 1 so that they can be replaced appropriately.

In order to supply and take out the powder, the rotary container 1 is provided with lid portions 9 and 9 which are normally closed in two places, for example, an upper portion and a lower portion, and which can be opened and closed when necessary. Has been.

When the raw material powders are mixed using the mixing apparatus of the present invention, the raw material powders a are supplied into one chamber 1A of the rotary container 1 as shown in FIG. By this supply, about 1/2 to 1/3 of the volume in the chamber 1A is filled with the raw material powder a.

Next, in the state shown in FIG. 1, the drive device 5 is operated to rotate the rotary container 1 about the horizontal rotary shaft 2 as a center of rotation, whereby the raw material powder a is stored in the rotary container 1. Can be mixed uniformly.

The principle of this mixing will be described with reference to FIG.

FIG. 5 (a) shows the situation when the rotation of the rotary container 1 is started. The principle powder a is one chamber 1A below the sieving part 7.
It is deposited in the lower part of the inside.

When the rotary container 1 is rotated clockwise as indicated by the arrow in the figure in the state shown in FIG. 5A, the raw material powder a is rotated by 0 to 90 ° of the container 1. , Fig. 5
As shown in (b) and (c), the weight of the powder itself moves along with the inclination of the container and the centrifugal force caused by the rotation of the container causes the powder to gradually move toward the sieving portion 7 and approach the sieving portion 7. 90 more
With rotation up to 180 °, the raw material powder a passes through the sieving portion 7 by its own weight while moving toward the sieving portion 7, and settles and accumulates in the other chamber 1B below the sieving portion 7. go.

In this way, the raw material powder a moves from the inside of the one chamber 1A into the other chamber 1B while passing through the sieving portion 7 by the first rotation from 0 to 180 °, and during this movement, the one chamber 1
The upper and lower positions of A and the other chamber 1B are reversed.

Similarly, the raw material powder a is rotated from 180 to 360 ° while passing through the sieving portion 7 from the inside of the other chamber 1B as shown in FIGS. 5 (f), 5 (g) and 5 (h). Meanwhile, room 1A
It moves to the side and finally returns to the initial state of FIG.

The raw material powder a circulates and moves in the rotary container 1 as the rotary container 1 rotates, passes through the sieving section 7 during this circular movement, and undergoes dispersion and mixing at each passage. By continuing the rotation for a predetermined time, it becomes possible to uniformly mix the raw material powder a.

In FIG. 5, the case where the raw material powder passes through the sieving portion twice each time the rotating container makes one rotation has been described. However, the number of passages per one rotation is a maximum of two times. In the state of 5 (e), a part of the raw material powder remains on the sieving part, and the operating condition is such that it passes through the sieving part during the rotation of FIG. 5 (e) to FIG. 5 (g). However, there is no particular problem. In order to improve the passability of the raw material powder through the sieving portion, a vibrator (not shown) for vibrating the sieving portion may be provided in the rotary container.

In the present invention, if the rotation speed of the rotary container 1 becomes too fast, the raw material powder will fly up inside the container 1 and it will be difficult to pass through the sieving portion 7 in a regular manner. The mixing operation is performed under a low speed rotation such that the body does not rise so much, for example, a low speed rotation of about 50 to 100 rotations / minute.

[0042]

According to the present invention, the following effects can be obtained.

A. Since it is possible to mix powder and gas while repeatedly circulating them in one closed container, there is no need to supply pressurized air or the like from the outside into the container, and a special means for separating powder and gas. Does not require the application of.

B. Since powder having a light specific gravity is not discharged at the same time by being accompanied by pressure air supplied from the outside, all powder is uniformly mixed in the container.

C. The powder is freely moved and circulated by repeating the rotation of the container and the passage of the sieving part, so that the powder can be uniformly mixed without being affected by the raw material composition, ratio, particle size, morphology, difference in distribution specific gravity and the like.

D. Since the powder is not generated due to the dispersion and mixing due to the low speed rotation of the container and the passage through the sieving part, it can be applied to the mixing of the powder whose composition of the raw material powder easily changes due to the heat of mixing without any trouble.

E. By replacing the sieve, you can select the most suitable mesh for the type of raw material powder,
It can be applied to a wide range of industrial fields such as food, chemicals, and plastics.

F. The number of parts of the mixing device is small and compact, the running cost is low, and the installation area is small, so the equipment costs are low. Therefore, it can be used with a dedicated machine and is most suitable for high-mix low-volume production.

G. Mixing time is very short. For example, when the volume of the container is 200 l, the mixing of the inorganic raw materials can be 2 tons or more per hour.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of FIG.

FIG. 3 is a side view schematically showing a modified example of the present invention.

FIG. 4 is a side view schematically showing still another modified example of the present invention.

FIG. 5 is an explanatory view schematically showing the mixing principle of the device of the present invention.

[Explanation of symbols]

 1 Rotating Container 2 Horizontal Rotating Shaft 3 Leg Stand 4 Bearing 5 Drive Device 6 Transmission Mechanism 7 Sieve Part 8 Lid Part

Claims (3)

[Claims] 1. A device for mixing powder in a closed rotary container that rotates at a low speed with a horizontal axis as a rotation center, wherein the interior of the rotary container is partitioned by a sieve through which powder can pass. The powder mixing apparatus is characterized in that the sieving portion is installed in at least one stage so as to be located in a plane including a horizontal axis parallel to the rotation center. 2. The mixing apparatus according to claim 1, wherein the center of rotation of the rotary container is at the center of the container. 3. The mixing apparatus according to claim 1, wherein the sieving portions are installed in parallel in a plurality of stages and are spaced from each other.