JP3222139U - Beads mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems associated with wear of a seal member of a seal device installed at a contact portion between a rotating portion and a slurry and adhesion of a deposit to the seal device in a bead mill. A bead mill in which a stirrer 4 for stirring beads in a cylindrical container and a bead separation device 5 are provided, wherein an upper storage tank 8 is installed above the upper lid 2 of the cylindrical container; The rotating shaft 9 connected extends from above the upper storage tank 8 through the slurry channel 7 into the cylindrical container, and at the position of the slurry channel 7, the impeller member 10 that applies pressure to the slurry to the rotating shaft 9 is connected ing. [Selected figure] 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 a slurry) by stirring hard particles (beads) which are stirring media in a container.

  There are various devices for pulverizing and dispersing particles in the slurry, but as the continuous type, the cylindrical container and the stirring are performed by rotating the rotating member (stirring bar) at high speed in a closed cylindrical container. There is an apparatus (bead mill) for pulverizing and dispersing particles in a slurry by generating a shearing force between particles and stirring media (beads) suspended in the slurry. For example, in the device (bead mill 1) of the invention disclosed in the patent document of document 1, there is a stirrer at the lower part of the cylindrical container, and rotation of this causes secondary processing of particle crushing and aggregation of primary particles. Perform particle dispersion processing. In the case of carrying out the pulverization / dispersion efficiently, processing is carried out by mixing beads having a diameter of about 0.03 to 3 mm in the slurry. In the bead mill 1, the beads are separated from the slurry for which the grinding and dispersion processes have been completed by the upper bead separation device.

  Moreover, the bead mill (bead mill 2) described in Patent Document 2 is an apparatus for performing both bead separation and stirring of a mixture of slurry and beads by a centrifugal separator. By improving the bead separation ability, there is a function of improving the particle shape at the time of dispersion treatment by adjusting the stirring power at a low speed rotation to reduce the excess crushing power. The stirrer is the same as the bead mill 1, but a movable stopper in the form of a nozzle is provided at the slurry outlet to form a gap narrower than the bead diameter at the outlet and the movable stopper. By passing the processed slurry through this gap, the beads are separated. Some bead mills having similar functions use a screen for bead separation.

  In the bead mill of the bead separation mechanism having a slit or screen narrower than the bead diameter at the outlet of the bead, the slurry is processed using 0.5 mm to several mm of beads due to the restriction of the gap for separating the beads. As the slurry passes through this gap, a relatively high pressure of 0.1 to 0.4 MPa is applied to flow the slurry through a bead mill equipped with a bead separation device of this type, as there is a large pressure drop.

  In addition, here, the pulverizing process refers to dividing a single particle into a plurality of small particles, and the dispersing process separates secondary particles so that primary particles are dispersed alone. Say what to do. In addition, primary particles refer to crystalline or amorphous single particles of a substance, and secondary particles generally form pseudo particles by contacting the surface of several to several thousand primary particles. Say what you have. The beads used for the pulverization treatment / dispersion treatment are particles of ceramic such as alumina or zirconia, particles of metal such as stainless steel, or plastic, and in general, spherical particles are preferable.

JP, 2002-143707, A JP, 2017-131807, A

  The bead mill is capable of continuous processing and has excellent pulverizing and dispersing functions such as pulverization and dispersion of micrometer size to nanometer size, but has the following problems. In a bead mill, in a cylindrical vessel, the beads are stirred to grind or disperse particles in the slurry, and the beads are separated in the cylindrical vessel. In a bead mill with a bead separation mechanism that separates the beads by passing the slurry through a narrow gap such as a slit or screen, there are fluid resistance when stirring the slurry and fluid resistance when passing through this gap, For this reason, it was necessary to press the slurry into a cylindrical vessel under pressure. The pressing pressure was a high pressure of about 0.1 to 0.4 MPa. On the other hand, in the rotary shaft for rotating the stirring bar in the cylindrical container, since the rotary sliding portion is in contact with the slurry, sealing of the rotary portion is necessary to prevent liquid leakage. Generally, a seal structure using a mechanical seal device or a rotary joint has been used to seal the rotating portion of such a relatively high pressure portion.

  Seal devices such as mechanical seals have contact parts between fixed parts and rotating parts, and store sealing liquid under pressure outside the seal apparatus so that high-pressure slurry in the container does not leak from the seal parts. It was a structure. Since this seal contact part part wears gradually, there existed a problem to which sealing performance falls temporally. As a result, the seal liquid leaks into the slurry, causing a problem of contaminating the slurry. In addition, there is a problem that wear powder of seal contact part parts (such as metal and ceramics) is mixed in the slurry. Furthermore, if the wear of the seal device becomes severe, the seal device needs to be replaced, which is an expensive problem. In particular, the wear of the seal in a slurry containing metal powder such as nickel was large and serious.

  A further problem of the sealing device is a device consisting of parts of a plurality of complex shapes, which as a whole is also a complex structure and may have joints or irregularities. In a bead mill having a sealing device, there is a problem that the slurry adheres to the joint or the uneven portion. In particular, in the processing of raw materials for food and medicine, there is a problem that the product is not a product due to the decay of the fixed matter, it is difficult to wash, and the slurry is contaminated after the change of breed. As described above, there are problems associated with the wear and adhesion of the sealing device, and new techniques for solving the problems have been desired.

  The bead mill of the present invention is a bead mill composed mainly of a cylindrical vessel, a stirrer, and a bead separation device. In addition, a stirrer for stirring beads is installed in the cylindrical container, and a slurry separation port installed in the lower lid is installed with a bead separation device of a vertically movable plug having a taper. ing. Further, above the upper lid of the cylindrical container, there is provided an upper storage tank which is in fluid communication with the cylindrical container with a slurry flow path. A rotating shaft extends from above the upper reservoir into the cylindrical vessel through the slurry flow path. The impeller member is fixed to the rotary shaft at the position of the slurry flow passage, and the stirrer is fixed within the cylindrical container. The impeller member exerts pressure on the slurry as it rotates, and has a structure in which the slurry flows downward.

  Further, the bead mill of the present invention is composed of an inner shaft and an outer shaft which can rotate independently of each other, and the outer shaft is coupled with the impeller member to rotate the impeller member, and the inner shaft is the stirrer. And the inner shaft and the outer shaft may be connected to a driving device capable of individually setting the number of rotations.

  Furthermore, the bead mill of the present invention has a structure in which a cylindrical vessel is connected to a slurry tank for circulation processing, and the upper storage tank and the slurry tank are pressure-free from the slurry tank in a state where no pressure is applied. The slurry may be connected to the water channel of the flowing structure, and the slurry outlet of the cylindrical container and the slurry tank may be connected by a pipe.

  The bead mill according to the present invention does not have the rotating part sealing device in contact with the slurry, so that there is no contamination of the product slurry with the worn sealing parts or seal liquid which is a problem with the contact member of the rotating device . Further, it is possible to solve the problem that particles in the slurry adhere to the rotating part sealing device and it is difficult to clean.

It is a bead mill of a 1st embodiment of the present invention, and is a thing of a type which drives a stirrer and an impeller member with the same axis of rotation. It is a bead mill of a 2nd embodiment of the present invention, and it is a thing of a type which can rotate a stirrer and an impeller member by an independent axis of rotation, respectively.

  The bead mill according to the first embodiment of the present invention is, as shown in FIG. 1, a cylindrical container comprising a cylindrical portion 1, an upper lid 2 and a lower lid 3 as main components, and a stirrer 4 connected to a rotary shaft 9. And a bead mill configured around the bead separation device 5. The cylindrical portion 1 and the upper lid 2 of the cylindrical container or the cylindrical portion 1 and the lower lid 3 may be integrated. The stirrer 4 may be rod-like, disc-like, plate-like or the like, but in the present invention, any structure may be used as long as it has the effect of stirring the slurry. The cylindrical portion 1 may be provided with a water cooling jacket for cooling the slurry in the cylindrical container.

  After stirring the mixture of the slurry and the beads, the beads are separated. In the present invention, a bead separating apparatus of the type in which the slurry is passed through a gap narrower than the diameter of the beads used to separate the beads is installed. The bead separation device of the type shown in FIG. 1, which allows the slurry to pass through a narrow gap, has a movable separator (bead separation device 5) with a tapered narrowing in the shape of a plug installed inside the slurry outlet 6. use. During the process, the gap between the bead separation device 5 and the slurry outlet 6 is opened so as to be a gap where the beads do not leak. In addition, it is possible to prevent clogging by detecting the pressure in the cylindrical container and adjusting the gap distance, which is more preferable. In addition, the bead separation device 5 may be a movable separator having a taper that narrows upward.

  Further, above the upper lid 2 of the cylindrical container, an upper storage tank 8 in communication with the cylindrical container with a slurry channel 7 is installed. The rotating shaft 9 extends downward from above the upper storage tank 8, and from the inside of the upper storage tank 8 through the inside of the slurry flow path 7, its end is in the cylindrical container. An impeller member 10 is installed in the slurry flow path 7 of the rotating shaft 9. In the cylindrical container, a stirrer 4 is installed on the rotary shaft 9. The impeller member 10 has, for example, a grooved cylindrical structure as described in FIG. 1 and has a structure in which pressure is applied to the slurry to flow downward as it rotates. The impeller member 10 may have any shape as long as it has a propeller shape, a turbo centrifugal type or the like that converts rotation into pressure.

  In a conventional bead mill, a mechanical seal structure (generally, a mechanical seal device) is installed between the upper portion of the cylindrical container and the rotating shaft. In order to cope with the liquid resistance during processing in the cylindrical vessel and the pressure loss in the bead separation device, the slurry is pushed into the mill with a pump or the like, and the inside of the cylindrical vessel is pressurized. Thus, a seal mechanism is required around the rotation axis. On the other hand, in the device of the present invention, the internal pressure of the cylindrical container is applied by the impeller member 10 installed between the rotating shaft 9 as the rotating part and the slurry flow path 7 as the fixed part. Even without the sealing mechanism, it is possible to create a pressure difference between the inside and the outside (in this case, the outside is the upper storage tank 8) of the cylindrical container.

  In the bead mill according to the first embodiment of the present invention, the slurry passes from the upper storage tank 8 through the slurry channel 7 into the cylindrical vessel and is stirred with the beads. At this time, the particles in the slurry are subjected to a grinding treatment or a dispersion treatment, and when the slurry passes through the gap between the slurry outlet 6 and the bead separating device 5 thereafter, only the beads remain in the cylindrical container, The slurry is discharged out of the cylindrical vessel.

  The drive device of the rotating shaft 9 may be anything as long as it can be rotated. For example, as shown in FIG. 1, the shaft drive pulley 11 is installed on the rotating shaft 9, and the belt 12 is connected to the motor side pulley 13 installed on the shaft of the drive motor 14 is there.

  Depending on the processing content, the outer peripheral speed of the rotor 4 may be kept low, but the flow rate of the processing slurry may be large, and the outer peripheral speed of the rotor 4 may be high, but the flow rate of the processing slurry may be reduced. In order to cope with such a change, the impeller member 10 may be replaced to change the relationship between the rotational speed and the flow rate. Accordingly, it is desirable that the impeller member 10 be easily replaceable.

  If the fluid delivery pressure of the impeller member 10 is insufficient, a pump may be installed in the middle of the pipe 17. In the bead mill of the first embodiment, when the pump is installed in the middle of the pipe 17, it is desirable to use pump speed change or vane control to change the processing flow rate.

  In the case of circulating operation of the bead mill described above, it is desirable to provide a slurry tank. A slurry tank 15 is installed in the bead mill of the first embodiment shown in FIG. The upper storage tank 8 and the slurry tank 15 are connected by a water channel 16 having a structure in which the slurry flows from the slurry tank 15 to the upper storage tank 8 in a state where no pressure is applied. The water channel 16 may be an open-type weir or a pipe.

  The slurry is pushed into the cylindrical device by the impeller member 10 with the operation of the bead mill, whereby the water level of the upper storage tank 8 is lowered, and the slurry flows from the slurry tank 15 to the upper storage tank 8 due to the water level difference. In the case where the flow by its own weight is insufficient, for example, when processing a high viscosity slurry, a flow assist device of a type that does not apply pressure to the slurry itself such as a paddle type or screw type may be installed in the water channel 16 . The treated slurry is discharged from the cylindrical vessel via the slurry outlet 6 and the bead separation device 5 and sent to the slurry tank 15 by the pipe 17. The slurry is circulated by this operation. Moreover, the stirring apparatus 18 is installed in the slurry tank 15 of the bead mill of 1st Embodiment shown in FIG.

  As the rotor 4 and the impeller member 10 are driven at the same rotational speed, the problem of a decrease in the slurry flow rate when lowering the outer peripheral speed of the rotor 4 occurs, but without replacing the impeller member 10, the rotor outer peripheral speed and When it is desired to change the relationship of the processing flow rate, it can be solved by using the bead mill of the second embodiment of the present invention shown in FIG. The bead mill according to the second embodiment of the present invention uses as a rotation shaft a biaxial rotary shaft consisting of coaxially installed inner shaft 19 and outer shaft 20 which can be independently rotated.

  In the bead mill of the second embodiment of the present invention, the inner shaft 19 extends from above the apparatus into the cylindrical container, and the stirrer 4 is fixed. The outer shaft 20 is coaxially installed on the outer side of the inner shaft 19, and the impeller member 10 is fixed in the slurry flow channel 7. The inner shaft 19 and the outer shaft 20 are driven independently. In the example of FIG. 2, the inner shaft 19 is driven by the inner shaft drive pulley 21, the inner shaft belt 22, and the inner shaft motor side pulley 23. The outer shaft 20 is driven by an outer shaft drive pulley 24, an outer shaft belt 25, and an outer shaft motor side pulley 26. In addition, a motor 14 for driving the inner shaft 19 and the outer shaft 20 is provided. Since the number of rotations of the inner shaft 19 and the outer shaft 20 can be set independently by selecting the diameter of each pulley, the stirring force adjustment by the stirrer 4 and the pushing flow rate of the slurry by the impeller member 10 are determined independently. be able to. In the bead mill of the second embodiment, the inner shaft 19 and the outer shaft 20 are driven by the same motor, but each may be driven by another motor.

  The dispersion process of nickel particles was performed using the bead mill of the present invention described in FIG. The size of the device was 120 mm for the inner diameter of the cylindrical container and 150 mm for the inner height. The rotation diameter of the stirrer 4 was 115 mm, and eight stirrers 4 were installed. The effective volume which deducted the volume of internal parts, such as the stirrer 4 of this apparatus, was 1.1 liter. The impeller member 10 was designed to flow 40 to 100 liters / hour of slurry at a standard rotation speed (900 to 2,500 RPM).

  The same nickel particles were dispersed using the bead mill of the present invention which can change the rotational speed of the impeller member 10 shown in FIG. The size of the device was the same as in Example 1. The impeller member 10 was designed to flow 40 to 100 liters / hour of slurry at a standard rotation speed (900 to 2,500 RPM).

  As a comparative example, processing was performed under the same conditions in a general bead mill having the same volume and the same stirrer. In this bead mill, the shape of the stirrer installed in the lower lid of the cylindrical container and the bead separating apparatus are the same as the apparatus of the second embodiment, but a mechanical seal is installed on the rotating shaft. The The slurry was fed into the bead mill by an externally installed pump.

  The raw material slurry used in the experiment was 30 liters of tapionol solution containing 5% by mass of metallic nickel powder having a primary particle size of 0.18 micrometers and a secondary particle size of 12 micrometers. In Example 1, using the above-mentioned apparatus, the bead of 0.5 mm diameter was used, and the outer peripheral speed of the stirrer 4 was 8 m / sec, and processed at a slurry flow rate of 30 liters per hour. In Example 2, the bead diameter and the outer peripheral speed of the stirrer 4 were the same, and the rotational speed of the impeller member 10 was increased to process the slurry at a flow rate of 80 liters per hour. Moreover, in the comparative example, it processed on the same conditions as the comparative example 2. FIG.

  Dispersion treatment was performed for 4 hours each, and the secondary particle size of particles in the slurry was measured. Within this time, the number of times the slurry passed through the bead mill was 4.0 times in Example 1, while it was 10.7 times in Example 2 and the Comparative Example. The treatment time per one time of the slurry is inversely proportional to the slurry flow rate, and in Example 2 and Comparative Example, although the number of times the slurry passed through the bead mill is large, the total residence time in the bead mill is Example 1, Example 2 and the comparative example were the same.

  In these treatments, the secondary nickel particle diameter after treatment is 0.23 micrometers in the 50% diameter (D50) from the small particle diameter side in Example 1 and 90% diameter (D90) in the small particle diameter side. In Example 2, D50 was 0.22 micrometers and D90 was 0.32 micrometers. In a comparative example, D50 was 0.23 micrometers and D90 was 0.31 micrometers. Met. All of the particles had a particle size that could satisfy the treatment purpose.

  However, in Example 2 and Comparative Example, since the number of times of slurry circulation passage is large, D90 is closer to the value of D50 and the particle size distribution is narrower than Example 1 in which the number of times of slurry circulation passage is small. As described above, in Example 2, since a large slurry flow rate can be flowed in the process, the number of circulations increases, and a product having a narrow particle size distribution and high uniformity can be obtained.

  With respect to the influence of the metallic nickel particles in the slurry on the parts, in the comparative example, wear of the mechanical seal was confirmed, and contamination of metal slurry of the mechanical seal was observed in the product slurry. On the other hand, in Examples 1 and 2 in which the impeller member 10 was installed for transporting the slurry, wear of the impeller member 10 and other parts was not observed.

  Thus, in the bead mill of the present invention, even when a highly abrasive slurry containing metal powder or the like is treated, it is possible to carry out processing with no wear of parts and stable processing for a long time. Moreover, the slurry contamination by the wear member of a mechanical seal was also lose | eliminated. Furthermore, in the device of the present invention having the coaxial two-shaft rotary shaft shown in FIG. 2, the circulating slurry flow rate can be maintained at an appropriate value regardless of the number of rotations of the stirrer 4 and thus additional effects such as slurry homogeneity improvement There is also.

  As described above, the bead mill according to the present invention has the same grinding / dispersion processing ability as the conventional bead mill, and the problem with the wear of the seal member due to the seal structure and the problem with the seal liquid leakage There was not.

  The bead mill according to the present invention comprises a grinding process and a dispersion process of a slurry containing powder such as ceramic, carbon nanotube, cellulose nanofiber, pigment, ink, paint, dielectric, magnetic substance, inorganic substance, organic substance, medicine, food, metal etc. Suitable for

DESCRIPTION OF SYMBOLS 1 ... Cylinder part 2 ... Top cover 3 ... Bottom cover 4 ... Stirrer 5 ... Bead separation device 6 ... Slurry outlet 7 ... Slurry flow path 8 ... Top storage tank 9 ... Rotating shaft 10 ... Impeller member 11 ... Shaft drive pulley 12 ... Belt 13 ... Motor side pulley 14 ... Drive motor 15 ... Slurry tank 16 ... Water channel 17 ... Pipe 18: Stirring device 19: Inner shaft 20: Outer shaft 21: Inner shaft drive pulley 22: Inner shaft belt 23: Inner shaft motor side pulley 24: Outer shaft Drive pulley 25 ··· Outer shaft belt 26 ··· Outer shaft motor side pulley

Claims (3)

A bead mill having a stirrer for stirring beads in a vertical cylindrical vessel and having a bead separation device for separating the beads by passing the slurry through a gap narrower than the diameter of the beads used,
An upper storage tank connected to the cylindrical container via a slurry flow path is installed above the upper lid of the cylindrical container,
It has a rotating shaft connected to a driving device above the upper storage layer, extends into the cylindrical container and connected to a stirrer.
An impeller member which applies pressure to the slurry to flow downward is connected to a position of the rotating shaft in the slurry channel,
A bead mill characterized in that the bead separation device is installed at a slurry outlet installed in a lower lid of the cylindrical container. The rotating shaft has an inner shaft and an outer shaft that can rotate independently,
The inner shaft and the outer shaft are connected to the drive device so as to individually control the number of rotations,
The bead mill according to claim 1, wherein the outer shaft is connected to the impeller member, and the inner shaft is connected to the stirrer. It further has a slurry tank,
The upper storage tank and the slurry tank are connected by a water channel having a structure in which the slurry flows from the slurry tank to the upper storage tank in a state where no pressure is applied to the slurry.
The bead mill according to claim 1 or 2, wherein the slurry outlet and the slurry tank are connected by a pipe.

Images