JP3217671U - Bead mill - Google Patents

Abstract

A bead mill for crushing and dispersing particles in a suspension of solid particles by stirring hard particles (beads) in a container.
A cylindrical container, a mechanical seal device, a two-type power transmission device, one or two drive motors, a centrifugal bead separation device, and a bead mill having a stirrer. It consists of three parts: a central shaft structure 7 for driving, an outer shaft structure 8 for driving the bead separating device 5, and a constraining portion structure 9 with a cylindrical container. The two power transmission devices are connected to the drive motor 21 and the central shaft structure 7 and to the drive motor 21 and the outer shaft structure 8. By appropriately setting the power transmission device, the central shaft structure 7 and the outer shaft structure 8 are rotated at different rotational speeds.
[Selection] Figure 1

Description

  The present invention relates to a bead mill that grinds and disperses particles in a suspension of solid particles (hereinafter referred to as slurry) by stirring hard particles (beads) in a container.

  There are various devices for pulverizing / dispersing particles in the slurry. As a continuous type, the cylindrical container and the stirrer are obtained by rotating a rotating member (stirrer) at high speed in a sealed cylindrical container. There is an apparatus (bead mill) that generates a shearing force between them and pulverizes and disperses particles in the slurry using a stirring medium (beads) suspended in the slurry. For example, in the apparatus (bead mill 1) of the invention disclosed in the patent document of Document 1, there is a stirrer at the lower part of a cylindrical container, and this rotates so that the particles are pulverized and the secondary particles are aggregated. Disperse the particles. In the case of efficiently carrying out pulverization / dispersion, the treatment is performed by mixing beads having a diameter of about 0.05 to 3 mm in the slurry. In the bead mill 1, the beads are separated from the slurry that has been crushed and dispersed by the upper centrifugal separation device.

Here, the pulverization process refers to dividing a single particle into a plurality of particles, and the dispersion process is a process in which secondary particles composed of a plurality of particles are separated and primary particles are dispersed alone. It is said to be in a state of being. The primary particles are single particles of a crystal or amorphous substance, and the secondary particles are generally composed of several to several hundreds of primary particles in contact with each other to form pseudo particles. Say what you are.

  Although it is not a patent document, Document 2 of the technical paper is for processing slurry in a sealed cylindrical container, and a stir bar is inserted into the cylindrical container from the bottom surface of the cylindrical container by a rotating shaft. An apparatus (bead mill 2) of a type in which a rotating and centrifugal force type bead separating apparatus is rotated by a rotating shaft inserted into the cylindrical container from the upper surface of the cylindrical container is disclosed. In the bead mill 2, since the stirrer and the separation device can be driven independently, the separation device can be rotated at a high speed even under the processing conditions in which the stirrer is rotated at a low speed. There are advantages that can be achieved.

  The beads used for the pulverization / dispersion treatment are particles made of ceramic such as alumina or zirconia, metal such as stainless steel, or plastic, and generally spherical. In the centrifugal bead separation device used in Document 1 or Document 2, when using beads having a large specific gravity such as ceramic or metal, beads can be separated accurately. In addition, when the slurry is processed using fine beads, particularly beads having a diameter of 0.2 mm or less, clogging occurs in the slit-type separation device and the screen-type bead separation device. The best way to separate them.

JP 2002-143707 A

Chemical equipment 2017 vol. 59, no. 3, p. 39-44

  The conventional dispersion apparatus for particles in a slurry has the following problems. In the bead mill 1 described in Document 1, the number of rotations of the stirrer and the bead separation device is the same. When it is necessary to suppress the pulverizing / dispersing force weakly, it is necessary to process the slurry by rotating the stirring bar at a low speed. The problem in this case is that the centrifugal force in the bead separating device is lowered, and the bead separating force is lowered, and there is a problem that the beads are mixed into the slurry after the treatment.

  On the other hand, in the bead mill 2, since the number of rotations of the stirrer and the bead separation device can be controlled independently, even in the process of rotating the stirrer at a low speed, the number of rotations of the bead separation device is set so that the beads do not leak. There was an advantage that it could be rotated and processed. However, the bead mill 2 requires a drive device for each of the stirrer and the bead separation device, and originally requires two drive motors, and also includes a pulley and a mechanical seal attached to the drive unit. Two sets are required. In addition, since the drive unit of the stirrer and the drive unit of the bead separation device are installed at different ends of the cylindrical container, the structure is complicated. As a result, there is a problem that the apparatus becomes expensive and increases in size.

  Further, when disassembling and maintaining the bead mill 2, it is necessary to first pull up the upper drive device set and the bead separation device, then remove the stirring bar in the cylindrical container, and further remove the cylindrical container from the lower drive device. there were. As a result, there is a problem that the disassembly and maintenance work becomes complicated. In addition, a lifter for moving up and down the upper drive set was necessary. As a result, the bead mill 2 is expensive and has poor maintainability.

  In this way, in a conventional bead mill for centrifuging beads, the stirrer and the beads are used when the stirrer is rotated at a low speed and the processing is performed so that the fine beads are not mixed in the slurry after processing. A bead mill that can independently control the rotation speed of the separation apparatus has been used. However, in such a bead mill, since the drive device becomes complicated and the device becomes large, a new type of bead mill that independently controls the number of revolutions of the stirrer and the bead separation device with the simplest drive device configuration. Was demanded.

  The invention according to claim 1 is a bead mill comprising a cylindrical container, a mechanical seal device, two types of power transmission devices, one or two drive motors, a centrifugal bead separation device, and a stirrer. Here, the cylindrical container has a slurry supply port in the lower part, and the upper part is fastened with a restraining part structure of a mechanical seal. The mechanical seal device is composed of three parts: a central shaft structure for driving the stirrer, an outer shaft structure for driving the bead separating device, and the restraint structure with the cylindrical container. A seal structure that allows rotation between the central shaft structure and the outer shaft structure and between the outer shaft structure and the restraint portion structure is provided. The mechanical seal device has a path for discharging the slurry that has passed through the bead separation device to the outside of the device. The two types of power transmission devices are connected to the drive motor and the central shaft structure, and to the drive motor and the outer shaft structure. By appropriately setting the power transmission device, the central shaft structure and the outer shaft structure can be rotated at different rotational speeds. The centrifugal bead separator has a structure that applies centrifugal force to the slurry by rotation. The stirring bar has a structure for stirring the inside of the cylindrical container.

  The invention according to claim 2 is the bead mill according to claim 1, further comprising a slurry discharge port having a slurry path inside the central shaft structure and further having a seal portion between the central shaft structure and the restraint portion structure. .

  The invention according to claim 3 is the bead mill according to claim 1, further comprising a slurry path between the outer shaft structure and the restraint portion structure. Furthermore, there is a space through which the slurry having a seal structure between the outer shaft structure and the restraint portion structure can pass, and the restraint portion structure has an outlet for discharging the slurry to the outside of the apparatus.

  A device according to claim 4 is the bead mill according to any one of claims 1 to 3, wherein two power transmission devices are connected to a shaft of one drive motor, and the power transmission device is a pulley. And a belt.

  According to a fifth aspect of the present invention, in the bead mill according to the fourth aspect, at least one of the two types of driving power transmission devices includes a pulley and a belt, and the pulley rotates without pulley replacement. It has a structure that can change the number change rate.

  The device of the present invention can operate the stirrer and the bead separation device at different rotational speeds, and functions as a mechanical seal device, two types of drive power transmission devices, one or two drive motors on the cylindrical container. It becomes the structure where only the board is installed. Therefore, although the conventional bead separation device has a function equivalent to that of a bead mill (bead mill 2) capable of operating at an independent rotational speed, the number of parts is small and a simple structure can be achieved. As a result, there is an effect that the load of the assembly work at the time of manufacture is reduced, and the disassembly and cleaning work after the processing operation is completed can be simplified.

It is an example of sectional drawing of the bead mill of this invention. It is an example of sectional drawing of the bead mill of this invention. It is sectional drawing of the mechanical seal apparatus of the bead mill shown in FIG.

  Hereinafter, a bead mill according to the present invention will be described with reference to the drawings. 1 and 2 show examples of the device structure of the present invention, and the structural difference between the two is that the structure in the mechanical seal device for discharging the slurry from the inside of the bead mill to the outside is different. It is. There are other similar structures that can implement the present invention, but typical examples are shown as representatives.

  FIG. 1 is a sectional view showing an example of a bead mill of the present invention. The bead mill has a structure in which a stirrer 4 and a bead separating device 5 are contained in a cylindrical container formed by an outer cylinder 1, an upper lid 2 and a lower lid 3. The cylindrical container may have a structure in which the outer cylinder 1 and the upper lid 2 and the outer cylinder 1 and the lower lid 3 are integrated. Although not shown in FIG. 1, the outer cylinder 1 may be provided with a water cooling jacket for cooling the slurry. A mechanical seal device is connected to the upper lid 2. The mechanical seal device includes three parts of the central shaft structure 7, the outer shaft structure 8, and the restraint structure 9 shown in FIG. 1, an attached slurry discharge path 10, a slurry outlet 11, a seal 12, a seal 13, and It is composed of a seal 14.

  The lower lid 3 is provided with a slurry supply port 6, and the raw material slurry is supplied from the slurry supply port 6 into the cylindrical container. In this figure, for convenience, the rotation axis is in the vertical direction, and the drive unit group is installed in the upper part of the cylindrical container. However, the direction of the rotation axis may be other angles such as horizontal.

  The stirrer 4 has a structure such as a rod-shaped or disk-shaped protrusion attached to the rotating shaft, and has a structure for stirring the inside of the cylindrical container, and is connected to the central shaft structure 7. In FIG. 1, the central shaft structure 7 enters the cylindrical container and the stirrer 4 is directly connected to the lower portion of the central shaft structure 7. However, the lower portion of the central shaft structure 7 can be divided. Things can be used. The stirrer 4 only needs to have a function of stirring the beads, and does not stick to a special shape such as a rod shape or a disk shape. The bead separation device 5 is a mechanism that applies centrifugal force to the slurry, and is connected to the outer shaft structure 8. For example, as shown in FIG. 3, the structure has a plurality of blades 23 between a pair of disks 22 and rotates to apply centrifugal force to the slurry.

  Between the central shaft structure 7, the outer shaft structure 8, and the restraining portion structure 9 of the mechanical seal device, there are a seal 12, a seal 13, and a seal 14 that allow rotation. The seal 12 is a seal structure that connects the central shaft structure 7 and the outer shaft structure 8, the seal 13 is the outer shaft structure 8 and the restraint portion structure 9, and the seal 14 is a seal structure that connects the central shaft structure 7 and the restraint portion structure 9. In general, sealing with a sealing liquid is common.

  Further, the mechanical seal device is provided with a path for discharging the processed slurry. The slurry discharge path has a structure for discharging to the outside of the apparatus via the center of the central shaft structure 7 and a structure for discharging the slurry for discharging the slurry to the outside of the apparatus between the outer shaft structure 8 and the restraining portion structure 9. These are all within the scope of the present invention. In FIG. 1, the slurry discharge path 10 is at the center of the central shaft structure 7, and a slurry discharge port 11 formed by a part of the restraint portion structure 9 connected to the central shaft structure 7 by a seal 14 is installed. In FIG. 1, the slurry discharge port 11 is installed between the pulley 15 and the pulley 16, but the slurry discharge port 11 may be installed on the pulley 15.

  In the apparatus of FIG. 1, a power transmission device including a pulley and a belt is shown as an example. The type of power transmission device may be a gear type or electromagnetic power transmission device in addition to a combination of a pulley and a belt. The central shaft structure 7 is connected to a pulley 15, and the belt 17 is hung on a pulley 19 connected to the pulley 15 and a rotation shaft of a drive motor 21. The outer shaft structure 8 is connected to a pulley 16, and the belt 18 is hung on a pulley 20 connected to the pulley 16 and a rotation shaft of a drive motor 21.

  The rotation of the drive motor 21 is transmitted to the central shaft structure 7 and the outer shaft structure 8 by the belt 17 and the belt 18 and finally transmitted to the stirrer 4 and the bead separating device 5. The operator of the bead mill has a plurality of pulleys with different diameters, and by exchanging these pulleys, the circumference ratio between the pulley 15 and the pulley 19 and the circumference ratio between the pulley 16 and the pulley 20 are changed. The ratio of the rotation speed of the separation device 5 can be changed. In addition, by using a pulley 15 and a pulley 19 or a pulley 16 and a pulley 20 that can change the number of revolutions, the ratio of the number of revolutions between the stirrer 4 and the bead separating device 5 is arbitrarily changed within a certain range. It is also possible. As such a pulley with a variable number of revolutions, for example, a pulley composed of two types of disks whose thickness decreases toward the outside is used. By adjusting the distance between the disks, the diameter of the circle in contact with the pulley and the belt can be adjusted.

  Thus, the rotation speed of the stirrer 4 (connected to the central shaft structure 7) is determined by the frequency determined by the inverter and the effective circumferential ratio of the pulley 15 and the pulley 19. The rotation speed of the bead separating device 5 (connected to the outer shaft structure 8) is determined by the frequency determined by the inverter and the effective circumferential ratio of the pulley 16 and the pulley 20. The effective circumferential ratio is the ratio of the circumferential length in contact with the belt on the inner surface of each pulley disk.

  In FIG. 1, an example with one drive motor is described for convenience, but there may be provided two drive motors. In that case, one drive motor is used to drive the central shaft structure 7 and the other drive motor is used to drive the outer shaft structure 8. By attaching a device for adjusting the rotational speed, such as an inverter, the rotational speed of each drive motor is set independently.

  FIG. 2 is a sectional view showing another example of the bead mill of the present invention. The difference from the apparatus shown in FIG. 1 is that the slurry discharge path 10 is installed between the outer shaft structure 8 and the restraining portion structure 9. The basic structure of the bead mill is the same as the apparatus shown in FIG. 1, but the mechanical seal apparatus is composed of the central shaft structure 7, the outer shaft structure 8, and the restraining portion structure 9 as shown in FIG. 2. It consists of three parts. The central shaft structure 7 and the outer shaft structure 8 are connected by a seal 12 so as to be able to rotate at an independent rotational speed, and a slurry discharge path 10 is formed between the outer shaft structure 8 and the restraining portion structure 9. A seal 13 is formed between the outer shaft structure 8 and the restraining portion structure 9, and a slurry outlet 11 continuing from the slurry discharge path 10 is installed in the restraining portion structure 9.

  The structures and functions of the stirring bar 4 and the bead separating device 5 are the same as those of the device shown in FIG. The conditions such as the axial direction of the bead mill installation are the same as those in the apparatus of FIG. The structure and function of the power transmission device are also the same as the device of FIG.

  The cylindrical container is filled with beads having a volume of about 50 to 90% of the effective volume. Here, the effective volume refers to the space volume in the cylindrical container excluding the volume of the member such as the stirring bar 4 in the cylindrical container. The raw material slurry supplied from the slurry supply port 6 to the cylindrical container is stirred together with the beads by the rotation of the stirrer 4 to be pulverized or dispersed. The treated slurry pushes the beads to the outer peripheral side of the cylindrical container (around the outer cylinder 1) by the centrifugal force of the bead separating device 5, so that only the slurry moves in the center direction in the bead separating device 5. To separate the beads. Thereafter, the slurry is discharged out of the bead mill device through the three discharge path 10 and the slurry discharge port 11 in the mechanical seal device.

  A bead mill of the present invention having the apparatus configuration of FIG. 1 was prepared. The inner diameter of the outer cylinder 1 was 75 mm, and the effective internal volume was 150 cubic centimeters. The stirrer 4 had four cylindrical rods installed in the center cylinder. The bead separation device 5 had a structure shown in FIG. The outer diameters of the stirring bar 4 and the bead separating device 5 were both 72 mm.

  In the apparatus of the present embodiment, the central shaft structure 7 of the mechanical seal device is connected to the drive motor 21 by a pair of pulleys (pulley 15 and pulley 19) having a variable rotation speed ratio and a belt 17. 8 is connected to a drive motor 27 by a normal pulley (pulley 16 and pulley 20) having a simple structure and a belt 18. An inverter for controlling the frequency was installed in the power source of the drive motor 21.

  First, the rotational speed of the drive motor 21 is determined so as to be the set rotational speed of the bead separating device 5. Thereafter, the effective circumferential ratio of the pulley 15 and the pulley 19 is determined so that the rotational speed of the drive motor 21 and the set rotational speed of the stirrer 4 are obtained. After determining the above setting conditions, the raw material slurry was introduced into the bead mill, the stirrer 4 and the bead separation device 5 were rotated, and processing was started.

  In the apparatus of this example, a slurry containing 5% by mass of titanium oxide particles (particle size: primary particle 120 nm, secondary particle 1.25 μm) was dispersed using 50 μm zirconia beads. In order to minimize damage to the titanium oxide particles, the outermost peripheral speed of the stirrer 4 was set to 6 m / s (rotation speed 1,590 RPM). On the other hand, the peripheral speed of the bead separation device 5 under the condition of separating 50 μm beads was set to 10 m / s (rotation speed: 2,560 RPM). Under the above conditions, the treatment flow rate is 20 liters / hour, which is a typical flow rate in the volume of the present apparatus, and the dispersion time of the slurry in the bead mill is 15 minutes later, and the titanium oxide secondary particle size is sufficiently dispersed at 155 nm. There was no bead leakage despite the small number of rotations of the stirrer 4. As described above, by using the bead mill of the present invention, it was possible to perform processing without leakage of microbeads of 100 μm or less even under conditions in which the bead hitting force during processing was suppressed.

  On the other hand, the same slurry was treated with 50 μm zirconia beads even in a bead mill having the same dimensions of the apparatus as the bead mill of this example and the same number of revolutions of the bead separator 5. As experimental conditions, the peripheral speeds of the stirring bar 4 and the bead separating device 5 were both 6 m / s, and the other conditions were the same. Although the dispersion of titanium oxide secondary particle diameter after the treatment was almost equal to 160 nm, bead leakage was observed. As described above, in the conventional bead mill, the bead mill of the present invention was able to appropriately perform pulverization / dispersion processing even under conditions where bead leakage was a problem.

  The present invention relates to a bead mill that pulverizes and disperses slurry containing particles of millimeter to nano size. The bead mill is suitable for pulverizing or dispersing powders of ceramics, carbon nanotubes, cellulose nanofibers, pigments, ink raw materials, paints, dielectric raw materials, magnetic materials, metals, organic substances and the like.

1 ... outer cylinder 2 ... upper lid 3 ... lower lid 4 ... stirrer 5 ... bead separator 6 ... slurry supply port 7 ... central shaft structure 8 ... outer shaft structure 9 ... restraint part structure 10 Slurry discharge path 11 Slurry outlet 12 Seal 13 Seal 14 Seal 15 Pulley 16 Pulley 17 Belt 18 Belt 19 Pulley 20 Pulley 21 Drive Motor 22 ... Disc 23 ... Blade

Claims (5)

A bead mill having a cylindrical container, a mechanical seal device, two power transmission devices, one or two drive motors, a centrifugal bead separation device, and a stir bar,
The mechanical seal device is composed of a central shaft structure for driving the stirrer, an outer shaft structure for driving the centrifugal bead separation device, and a constraining portion structure with a cylindrical container,
A seal structure that allows rotation between the central shaft structure and the outer shaft structure and between the outer shaft structure and the restraint structure;
The mechanical seal device has a path for discharging the slurry from the centrifugal bead separation device to the outside of the device via the mechanical seal device.
The cylindrical container has a slurry supply port at one end and the other end is fastened with the restraint portion structure of the mechanical seal device,
The power transmission device is a structure that connects the drive motor and the central shaft structure and the drive motor and the outer shaft structure and drives the central shaft structure and the outer shaft structure at independent rotational speeds.
The centrifugal bead separation device is a structure that applies centrifugal force to the slurry,
The bead mill, wherein the stirrer has a structure for stirring the slurry inside the cylindrical container. Having a slurry path inside the central shaft structure;
The mechanical seal device has a seal structure that seals between the central shaft structure and the restraint portion structure;
The bead mill according to claim 1, wherein the constraining portion structure has a slurry discharge port communicating with the slurry path. A slurry discharge path between the outer shaft structure and the restraint structure;
2. The bead mill according to claim 1, wherein the constraining portion structure has a slurry discharge port for discharging the slurry from the slurry discharge path to the outside of the apparatus. The two types of power transmission devices are a combination device of a pair of two pulleys and a belt,
The first combination device is used to drive the central shaft structure;
The bead mill according to any one of claims 1 to 3, wherein the second combination device is used for driving an outer shaft structure.   Of the two types of power transmission devices, at least one of them uses a power transmission device composed of two pulleys and a belt having a structure capable of changing the rotation speed change rate without replacement. The bead mill according to claim 4.

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