JP6841421B2 - Powder mixing and stirring device - Google Patents

Description

The present invention relates to a powder mixing and stirring device.

Conventionally, various studies have been made on an apparatus for uniformly mixing and stirring two or more kinds of powders (for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 11-57439 JP-A-2007-54729

An object of the present invention is to provide a novel powder mixing and stirring device capable of uniformly mixing and stirring two or more types of powder.

As a result of diligent studies on the configuration of a novel powder mixing and stirring device, the present inventor came up with the following configuration and arrived at the present invention.

That is, according to the present invention, a cylindrical container for accommodating the powder to be mixed, a means for rotating the cylindrical container in the circumferential direction of the cylinder, and the inside of the cylindrical container. A stirring blade that is rotatably fixed around the cylindrical axis and abuts on the inner peripheral wall surface of the container over the entire length in the cylindrical axis direction of the container, and a means for rotating the stirring blade relative to the container. The stirring blade includes a means for intermittently rotating the stirring blade in synchronization with the rotation of the container, and the stirring blade causes the powder in the container to move from both ends to the center side as the stirring blade rotates. A mixing and stirring device is provided, characterized in that it has a shape that moves toward it.

As described above, according to the present invention, there is provided a novel powder mixing and stirring device capable of uniformly mixing and stirring two or more types of powder.

The external view of the powder mixing stirrer of this embodiment. The external view of the stirring blade of the powder mixing stirrer of this embodiment. The figure for demonstrating the use procedure of the powder mixing stirrer of this embodiment. The figure which shows the left side surface of the powder mixing stirrer of this embodiment in chronological order. The figure which looked at the powder mixing stirrer in the contact period from the front. The external view of the stirring blade used in this experiment. A graph showing the experimental results.

Hereinafter, the present invention will be described with reference to the embodiments shown in the drawings, but the present invention is not limited to the embodiments shown in the drawings. In each of the figures referred to below, the same reference numerals are used for common elements, and the description thereof will be omitted as appropriate.

FIG. 1 shows the appearance of the powder mixing and stirring device 100 according to the embodiment of the present invention. Here, FIG. 1A is a front view of the device, FIG. 1B is a left side view of the device viewed from the left side of the paper surface, and FIG. 1C is a right side view of the device viewed from the right side of the paper surface. It is a figure.

The powder mixing and stirring device 100 of the present embodiment includes a cylindrical container 10 for accommodating two or more types of powder to be mixed, and a short cylindrical container fixing portion 24 for fixing the container 10. , The pedestal 20, the support portion 22 projecting from the pedestal 20 and rotatably supporting the container fixing portion 24 in the circumferential direction of the cylinder via the bearing 23, and the motor 30 for rotating the container fixing portion 24. , The friction wheel 18 and the braking means 40 are included.

A pulley 32 is fixed to the outer peripheral surface of the container fixing portion 24 in the present embodiment, and the rotational power of the motor 30 is transmitted to the pulley 32 via the pulley 34 and the pulley belt 36, so that the container fixing portion 24 is shafted. It is configured to rotate around A.

Here, the container fixing portion 24 is formed with an eccentric hole 26 as shown on the right side of FIG. 1A. The eccentric hole 26 is a columnar through hole having an eccentric center with respect to the rotation center (axis A) of the container fixing portion 24 and having an inner diameter substantially equal to the outer diameter of the container 10. , The container 10 is fixed to the container fixing portion 24 by being fitted into the eccentric hole 26.

The container 10 in the present embodiment is configured as a closed container in which lids 13a and 13b are fitted to the openings at both ends of the cylindrical member 12, and a stirring blade 16 has a cylindrical shaft B of the container 10 inside the container 10. It is rotatably fixed in the center. Here, the stirring blade 16 is fixed to the rotating shaft 17, and the friction wheel 18 is fixed to the rotating shaft 17. In the present embodiment, the stirring blade 16 is rotatably fixed by fitting both ends of the rotating shaft 17 to bearings (not shown) provided on the lids 13a and 13b, respectively. In the present embodiment, the cylindrical shaft B coincides with the center of the eccentric hole 26 in a state where the container 10 is fitted in the eccentric hole 26.

The braking means 40 in the present embodiment includes a support portion 44 projecting onto the pedestal 20 and an elastic body 42 fixed on the support portion 44. Here, the fixing position of the elastic body 42 is positioned so that the friction wheel 18 comes into contact with the elastic body 42 when the vertical position of the container 10 becomes the lowest as the container fixing portion 24 rotates. .. The elastic body 42 may be deformed by the contact with the friction wheel 18 to impart frictional resistance to the friction wheel 18, and an elastomer such as rubber can be exemplified.

Here, the shape of the stirring blade 16 rotatably fixed inside the container 10 will be described with reference to FIG.

As shown in FIG. 2, the stirring blade 16 of the present embodiment has a line-symmetrical structure with the rotation axis B as the axis of symmetry, and more specifically, the one-letter-shaped stirring piece 16a and the one-letter-shaped stirring piece 16b. A structure is provided in which the agitating piece 16c having a bent central portion when viewed from the front and the agitating piece 16d having an inverted shape having a bent central portion when viewed from the front are continuously integrated.

Here, the stirring piece 16a and the stirring piece 16b are in a parallel relationship with each other, and when the stirring blade 16 is fixed in the container 10, the stirring piece 16a hits the entire length of the inner wall bottom surface 10a of the container 10 in the radial direction. The size and shape of the stirring piece 16b are designed so that the stirring piece 16b comes into contact with the container 10 over the entire length of the inner wall bottom surface 10b in the radial direction.

On the other hand, the stirring piece 16c and the stirring piece 16d are in a line-symmetrical relationship with each other with the cylindrical axis B as the axis of symmetry, and when the stirring blade 16 is fixed in the container 10, each of them has the total length in the cylindrical axis direction of the container 10. The size and shape of the container 10 are designed so as to come into contact with the inner peripheral wall surface 10c of the container 10. In actual mounting, it is preferable to optimize the shape of the stirring blade 16 as appropriate. For example, the area of the portion of the stirring pieces 16c and 16d that comes into contact with the inner peripheral wall surface 10c is the same as the inner peripheral wall surface 10c. It is preferable to make it as small as possible so that the powder does not stay between them.

The structure of the powder mixing / stirring device 100 of the present embodiment has been described above, but subsequently, the procedure for using the powder mixing / stirring device 100 will be described with reference to FIG.

In using the powder mixing and stirring device 100, first, as shown in FIG. 3A, the lid 13a is removed from the container 10. Next, as shown in FIG. 3B, the stirring blade 16 is inserted into the container 10 and one end of the rotating shaft 17 is fitted into the bearing 14b of the lid 13b. Then, two or more kinds of powders to be mixed are put into the container 10.

Next, as shown in FIG. 3C, the container 10 containing the powder is contained by fitting the other end of the rotating shaft 17 into the bearing 14a of the lid 13a and fitting the lid 13a into the cylindrical member 12. To seal. At this time, the space between the rotating shaft 17 and the opening of the lid 13 is sealed by the O-ring 15 so that the powder does not leak to the outside.

Next, the friction wheel 18 and the stirring blade 16 are connected by fitting and fixing the rotating shaft 17 of the stirring blade 16 into the through hole 18a formed in the center of the friction wheel 18.

Finally, after fitting and fixing the container 10 to which the friction wheel 18 is connected into the eccentric hole 26 of the container fixing portion 24, the motor 30 is driven to rotate the container fixing portion 24.

The procedure for using the powder mixing / stirring device 100 of the present embodiment has been described above. Next, the principle that the powder is uniformly mixed and stirred in the powder mixing / stirring device 100 will be described.

4 (a) to 4 (d) show the left side surface of the driven powder mixing and stirring device 100 in chronological order. In the lower part of each drawing, only the container fixing portion 24, the container 10 and the stirring blade 16 are extracted and shown in order to help the understanding of the invention. Further, in FIG. 4, in order to express the rotation of the container fixing portion 24 and the rotation of the friction wheel 18, for convenience, a symbol (▼) is attached to the container fixing portion 24, and a symbol (▲) is attached to the friction wheel 18. Was attached.

As described above, in the present embodiment, since the container 10 is fixed to the eccentric hole 26 of the container fixing portion 24, as the container fixing portion 24 rotates, FIGS. 4 (a) to 4 (d) show. As shown, the position of the container 10 moves up and down in the vertical direction. As a result, in the present embodiment, the friction wheel 18 connected to the stirring blade 16 in the container 10 comes into contact with the elastic body 42 of the braking means 40 once for each rotation of the container fixing portion 24. ..

Here, during the period when the friction wheel 18 does not come into contact with the elastic body 42, the container fixing portion 24 and the friction wheel 18 rotate integrally with respect to the container 10 as shown in FIGS. 4A to 4B. The relative position of the stirring blade 16 in the rotation direction is not displaced.

On the other hand, during a short period in which the friction wheel 18 contacts the elastic body 42 (hereinafter referred to as a contact period), the friction wheel 18 is stopped by the frictional resistance generated between the elastic body 42 and the friction wheel 18, so that the container is fixed. Only the portion 24 rotates. As a result, during the contact period, as shown in FIGS. 4 (c) to 4 (d), the relative position of the stirring blade 16 in the rotation direction with respect to the container 10 is displaced. That is, in the present embodiment, the stirring blade 16 rotates relative to the container 10 during the contact period.

FIG. 5 is a front view of the powder mixing / stirring device 100 during the contact period. During the contact period, as the stirring blade 16 rotates relative to the container 10, the powder P near the inner peripheral wall surface of the container 10 is scraped off by the stirring pieces 16c and 16d. Then, at this time, the scraped powder P moves from both end sides to the center side of the container 10 along the stirring pieces 16c and 16d formed in a U shape.

That is, in the present embodiment, the powder in the container 10 is agitated in the circumferential direction of the container 10 by the rotation of the container 10 accompanying the rotation of the container fixing portion 24, while being agitated in synchronization with the rotation cycle of the container 10. The intermittent rotation of the blade 16 also agitates the container 10 in the axial direction, so that the powder is uniformly mixed and agitated.

Here, when powders having significantly different specific gravities are mixed, a separation action due to centrifugal force acts strongly in the radial direction of the container 10 as the container 10 rotates. In response to this problem, in the present embodiment, the powder is periodically scraped off from the inner peripheral wall surface of the container 10 and freely falls in the container 10, so that the separating action acting on the powder is canceled each time. It will be. Therefore, according to the present embodiment, even a combination of powders having significantly different specific gravities can be uniformly mixed and stirred.

In the present embodiment, in view of the purpose of canceling the separating action acting on the powder, the rotation cycle of the container 10 is set to a time slightly longer than the time required for the powder to freely fall the inner diameter distance of the container 10. (That is, the rotation cycle of the container fixing portion 24) is preferable.

On the other hand, the adhesive powder tends to form a lump in the container 10. On the other hand, constantly rotating the stirring blade 16 keeps compressing the powder, which promotes the generation of lumps. In response to this problem, in the present embodiment, the powder mass generated in the container 10 is decomposed by the action of vibration generated by intermittently rotating the stirring blade 16. Therefore, according to the present embodiment, even an adhesive powder can be uniformly mixed and stirred.

Although the present invention has been described above with the embodiment, the present invention is not limited to the above-described embodiment, and the following design changes can be made.

The stirring blade 16 may have a shape capable of moving the powder from both end sides of the container 10 toward the center side as the stirring blade 16 rotates. For example, two spirals having opposite traveling directions form the container. Each includes a first stirring piece formed by connecting the central portion of 10 as a boundary and a second stirring piece having a line-symmetrical relationship with the first stirring piece with the cylindrical axis B of the container 10 as the axis of symmetry. A stirring blade may be adopted in which the stirring piece abuts on the inner peripheral wall surface 10c over the entire length of the container 10 in the cylindrical axis direction.

Further, the mechanism for relatively rotating the stirring blade 16 may be any means for intermittently applying a braking torque to the rotating shaft 17 fixed to the stirring blade 16, and has the above-described configuration (eccentric hole 26). Instead of the container fixing portion 24, the friction wheel 18, and the braking means 40) provided with the above, for example, an electric magnet that intermittently applies a braking torque to the rotating shaft 17 may be adopted.

Within the scope of other embodiments, it is included in the scope of the present invention as long as the action / effect of the present invention is exhibited.

Although the present invention has been described above with embodiments, the present invention is not limited to the above-described embodiments, and the actions and effects of the present invention can be exhibited within the scope of other embodiments that can be inferred by those skilled in the art. As long as it works, it is included in the scope of the present invention.

<Manufacturing of powder mixing and stirring device>
An experimental device equivalent to the powder mixing and stirring device 100 shown in FIG. 1 was produced. In this experiment, a container 10 having an inner diameter of 35 mm, a length of 127 mm, and a capacity of 70 ml was prepared, and a stirring blade suitable for the inner diameter of the container 10 was designed and manufactured by a 3D printer. FIG. 6 shows the stirring blade 16x used in this experimental device. As shown in FIG. 6, the stirring blade 16x is designed so that the thickness of the portion of each stirring piece in contact with the inner peripheral wall surface of the container 10 is reduced.

<Mixing and stirring experiment>
In this experiment, potato starch (20 g) and aluminum oxide powder (1 g) were put into the container 10 and fixed to the container fixing portion 24, and then the container fixing portion 24 was rotated at a constant rotation speed for 15 minutes. In this experiment, seven different conditions were set for the rotation speed [rpm] of the container fixing portion 24 within the range of 400 rpm to 1000 rpm.
<Experimental results>

After rotating the container fixing portion 24 at a set rotation speed for 15 minutes, the powder in the container 10 was collected and photographed. After obtaining the position and number of particles existing within a predetermined range from the photograph taken using the self-made software, calculate the distance to the nearest particle for each particle and obtain the average value d. It was. Next, the theoretical distance D between the particles when the same number of particles were arranged in the same range in a square grid was calculated, and the ratio (d / D) of the average value d to the theoretical distance D was calculated as the uniformity α. ..

FIG. 7 shows the relationship between the rotation speed [rpm] of the container fixing portion 24 and the uniformity α. As shown in FIG. 7, the uniformity α showed the maximum value (0.58) at 600 rpm. This was a sufficiently high value as compared with the value of uniformity α (0.54) when the particles were randomly distributed. Further, according to this result, the uniformity α is maximum when the rotation speed (600 rpm) is slightly smaller than the rotation speed (about 700 rpm) whose cycle is the time required for the powder to freely fall within the inner diameter distance (35 mm) of the container 10. It was shown to be.

10 ... Container, 10a ... Inner wall bottom surface, 10b ... Inner wall bottom surface, 10c ... Inner peripheral wall surface, 12 ... Cylindrical member, 13a ... Lid, 13b ... Lid, 14a ... Bearing, 14b ... Bearing, 15 ... O-ring, 16 ... Stirring blade , 16a ... stirring piece, 16b ... stirring piece, 16c ... stirring piece, 16d ... stirring piece, 16x ... stirring blade, 17 ... rotating shaft, 18 ... friction wheel, 18a ... through hole, 20 ... pedestal, 22 ... support part, 23 ... Bearing, 24 ... Container fixing part, 26 ... Eccentric hole, 30 ... Motor, 32 ... Pulley, 34 ... Pulley, 36 ... Pulley belt, 40 ... Braking means, 42 ... Elastic body, 44 ... Support part, 100 ... Powder Body mixing stirrer

Claims (5)

A cylindrical container for storing the powder to be mixed and
A means for rotating the cylindrical container in the circumferential direction of the cylinder, and
A stirring blade that is rotatably fixed inside the cylindrical container about its cylindrical axis and abuts on the inner peripheral wall surface of the container over the entire length in the cylindrical axis direction of the container.
A means for rotating the stirring blade relative to the container, and a means for intermittently rotating the stirring blade in synchronization with the rotation of the container.
Including
The powder mixing and stirring device is characterized in that the stirring blade has a shape that moves the powder in the container from both end sides toward the center side as the stirring blade rotates. The stirring blade
A pair of agitated pieces in a line symmetry with each other with the cylindrical axis of the container as the axis of symmetry
The powder mixing and stirring device according to claim 1. The stirring blade
The first stirring piece formed by connecting two spirals facing each other in the traveling direction with the central portion of the container as a boundary and the first stirring piece having the cylindrical axis of the container as the axis of symmetry are in a line symmetric relationship. Includes a second stirrer,
The powder mixing and stirring device according to claim 1. The means for rotating the container
A columnar container fixing portion provided with an eccentric hole for fitting and fixing the container, and
A means for rotating the container fixing portion in the circumferential direction of the cylinder, and
Including
The means for intermittently rotating the stirring blade is
The friction wheel connected to the stirring blade and
An elastic body that intermittently contacts the friction wheel to impart frictional resistance in synchronization with the rotation of the container fixing portion.
including,
The powder mixing / stirring device according to any one of claims 1 to 3. The means for intermittently rotating the stirring blade is
A means for intermittently applying braking torque to the rotating shaft of the stirring blade is included.
The powder mixing / stirring device according to any one of claims 1 to 4.