Classifier, and powder classification method with use of the same

Abstract

To provide a classifier which can perform classification while ensuring a prescribed throughput without breakage of a mesh even when classifying, for example, powders with strong adhesiveness such as an electrode material of a lithium ion battery and so on.SOLUTION: Disclosed is a classifier comprising: a classification mesh for classifying powders; at least two pressing plates capable of pressing so as to sandwich the classification mesh and the powders of classification object; and a vibration mechanism which vibrates the pressing plate. Further, disclosed is a classification method with use of the classifier.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a classification device for classifying powder and a method for classifying powder using the same. [Background technology]

[0002] A known technology for classifying powder is disclosed in Patent Document 1. Patent Document 1 describes a classifying device having a mesh member that is circular in top view and classifies powder, a spatula that is positioned above the mesh member and rotates via a vertically installed rotating shaft to press the powder against the mesh member, and a motor that rotates the rotating shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-36864 Summary of the Invention [Problem to be solved by the invention]

[0004] When trying to classify highly adhesive powders using the technology described in Patent Document 1, it is necessary to press the spatula against the mesh with a strong force to classify them. However, because the spatula is pressed against one side of the mesh member, if the pressing force is strong, the mesh may stretch, causing the openings to widen, or the mesh may be damaged.

[0005] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a classification device that is capable of classifying highly adhesive powders, such as electrode materials for lithium ion batteries, while ensuring a predetermined throughput and without damaging the mesh, and a method for classifying powders using the same. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention is configured as follows. A classification device including a classification mesh for classifying powder, at least two pressure plates capable of pressing the classification mesh and the powder to be classified in a sandwiched manner, and a vibration mechanism for vibrating the pressure plates, and a powder classification method using the same. Effect of the Invention

[0007] According to the present invention, it is possible to provide a classification device that can classify highly adhesive powders while ensuring a predetermined throughput without damaging the mesh, and a classification method using the same. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a classification device according to a first embodiment. [Diagram 2] FIG. 11 is a top view showing a schematic configuration of a classification device according to a second embodiment. [Diagram 3] FIG. 11 is a cross-sectional view showing the structure of a supply unit 15 in the second embodiment. [Figure 4] FIG. 11 is a top view showing the shape of an opening of a mask 29 in Example 2. [Diagram 5] FIG. 11 is a cross-sectional view showing the structure of a classifying section 16 in a second embodiment. [Figure 6] FIG. 11 is a cross-sectional view showing the structure of a mesh cleaning portion 17 in Example 2. [Figure 7] FIG. 11 is a top view showing a schematic configuration of a classification device according to a third embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing the structure of a classifying section 50 in a third embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing a schematic configuration of a classification device in a fourth embodiment. [Figure 10] FIG. 13 is a bottom view of the base plate 61 in the fourth embodiment. [Figure 11] FIG. 13 is a top view of a rotating plate 65 in the fourth embodiment. [Figure 12] FIG. 13 is a top view of a base plate 76 according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The examples are illustrative for explaining the present invention, and are omitted and simplified as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] When there are multiple components having the same or similar functions, they may be described by using the same reference numerals with different subscripts, or when there is no need to distinguish between these multiple components, the subscripts may be omitted. EXAMPLES

[0012] Example 1 will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing a schematic configuration of a classification device according to Example 1. The classification device 1 includes a feeder 2, a classification mesh 3, a lifting mechanism 4, 11, ultrasonic vibrators 5, 10, a vibration plate 6, a suction housing 7, aperture plates 8, 9, a suction nozzle 12, an air injection nozzle 13, and a roller 14.

[0013] The feeder 2 supplies a fixed amount of powder onto the classification mesh 3. The classification mesh 3 is configured in a loop shape, and conveys the powder while being circulated by a roller 14. The classification mesh 3 has an opening (roughness) equal to or less than the lower limit of the size of the foreign particle to be removed, and is larger than the median particle size of the powder. Here, the opening of the classification mesh 3 may be larger than the size of the foreign particle, but if it is only slightly larger, the foreign particle can be substantially removed and the throughput can be improved, but if it is smaller than the size of the foreign particle, the removal can be ensured and reliability can be improved. If it is not desired to mix metallic foreign matter from the mesh into the powder, a resin mesh such as nylon can be used as the material for the classification mesh 3.

[0014] Two aperture plates 8 and 9 are attached to the suction housing 7. The aperture plate is for sucking in the powder that has passed through the classification mesh while flattening the shape of the classification mesh when the classification mesh 3 is pressed against the powder, and is a highly rigid plate with multiple apertures that penetrate vertically for sucking in the powder. In order to suppress uneven suction caused by the opening position / non-opening position, it is desirable to make each opening small and arrange them at a high density to increase the opening rate, but this reduces rigidity and may cause deformation when pressed. If the aperture plate deforms, the classification mesh will deform and the opening shape of the mesh will change, making it impossible to obtain the expected classification performance. In addition, when targeting materials with an average particle size of several μm to several tens of μm, such as electrode materials for lithium-ion batteries, classification meshes with openings of 100 μm or less are often used, but such meshes are weak in strength and may break if they are greatly deformed. Therefore, by installing two aperture plates with different opening sizes and opening rates, it is possible to achieve both suppression of uneven suction and rigidity. Compared with the aperture plate 9, the aperture size of the aperture plate 8 is made smaller and arranged at a higher density to increase the aperture ratio.

[0015] If it is desired to prevent metallic foreign matter from being mixed into the powder, it is desirable to form the aperture plates 8 and 9 and the suction housing 7 from resin, but if sufficient rigidity cannot be obtained, they may be formed from metals such as stainless steel or aluminum. In that case, it is desirable to form a non-metallic layer such as a resin coating such as fluororesin or a DLC coating on the area that comes into contact with the powder. Also, if sufficient rigidity is obtained with the aperture plate 8 alone, the aperture plate 9 may be made of a resin mesh such as nylon.

[0016] The suction housing 7 is attached to a lifting mechanism 11, and is brought close to the classification mesh 3 during classification, and is moved away from the classification mesh 3 when the classification mesh 3 is fed by rollers.

[0017] It is preferable to use a hard material such as metal for the diaphragm 6 in order to suppress energy attenuation of the ultrasonic vibrator. To prevent contamination of the powder, it is preferable to apply a fluororesin coating, PEEK coating, DLC coating, or anodizing treatment to the surface of the diaphragm 6 in the case of aluminum.

[0018] The ultrasonic vibrator 5 is fixed to the vibration plate 6, which is fixed to the lifting mechanism 4. During classification, the vibration plate 6 is lowered by the lifting mechanism 4, and the powder and the classification mesh 3 are pressed against the opening plate 8. After that, high-frequency power is applied to the ultrasonic vibrator 5 to vibrate it. This causes the powder to fluidize, and particles smaller than the mesh size of the classification mesh 3 pass through the classification mesh 3. By applying vibration while pressing against the powder, even highly adhesive powder can be broken down into agglomerates and fluidized. By simultaneously applying vibration and suction, the powder that has passed through the classification mesh 3 is suctioned and collected via the suction housing 7. In addition, by applying vibration at this time using the ultrasonic vibrator 10 attached to the suction housing 7, fluidization is further promoted, and the speed at which the powder passes through the classification mesh 3 is improved.

[0019] During classification, a control unit (not shown) controls the lifting mechanism 4 to adjust the height of the vibration plate 6 so as to follow the reduction in the powder layer thickness that accompanies the passage of the powder through the classification mesh 3. Alternatively, the vibration plate 6 may be made to follow the reduction by an elastic member such as a spring.

[0020] After classification, the powder that does not pass through the classification mesh 3 is sucked and collected by the suction nozzle 12. If the powder is highly adhesive or if the mesh is clogged, suction alone may not be enough to remove it, so air is sprayed from below the mesh by the air injection nozzle 13 to ensure that the powder on the mesh is removed.

[0021] As described above, according to this embodiment, by applying vibration while pressing with the vibration plate and the aperture plate, it is possible to apply vibration while strongly pressing the powder against the mesh while suppressing deformation and damage of the mesh, so that it is possible to improve the classification throughput even for powders with strong adhesion. Furthermore, by fixing an ultrasonic vibrator to the vibration plate, the distance between the vibrator and the powder is short, and strong vibration energy can be applied to the powder, so that the classification throughput can be further improved.

[0022] In this embodiment, an example has been described in which two aperture plates 8 and 9 with different apertures are installed, but as long as it is possible to achieve both the flatness of the classification mesh and the suppression of uneven suction, a single aperture plate may be used. EXAMPLES

[0023] Example 2 will be described with reference to Figs. 2 to 6. Fig. 2 is a top view showing a schematic configuration of a classification device in Example 2. In Example 1, the classification mesh is configured in a loop shape, but in Example 2, the classification mesh is fixed to a frame and the frame is transported between each processing section, thereby improving the workability when replacing the mesh. The classification device in Example 2 includes a supply section 15, a classification section 16, a mesh cleaning section 17, a mesh transport mechanism 18, and a mesh frame 23.

[0024] The mesh frame 23 has a classification mesh 25 fixed to a frame 24, and powder is placed on the classification mesh 25 and transported between each treatment section.

[0025] The classification mesh 25 has an opening size equal to or smaller than the lower limit of the size of the foreign particles to be removed, and larger than the median particle size of the powder. Here, even if the opening size of the classification mesh 25 is slightly larger than the size of the foreign particles, it is possible to substantially remove the foreign particles and improve throughput, but a mesh size smaller than the size of the foreign particles allows for more reliable removal and increases reliability. If it is not desired to mix metallic foreign particles originating from the mesh into the powder, it is desirable to use a resin mesh such as nylon as the material for the classification mesh 3.

[0026] The mesh transport mechanism 18 transports the mesh frame 23 between each processing section, and includes a hand 19, an adsorption pad 20 that sucks with negative pressure or the like, a linear motion mechanism 21, and a rotation mechanism 22. The mesh frame 23 arranged at each processing section is fixed by the adsorption pad 20, and is transported by the linear motion mechanism 21 to directly above the rotation mechanism 22, after which it is rotated by the rotation mechanism 22 and transported by the linear motion mechanism 21 to the next processing section.

[0027] The supply unit 15 is used to place (or place, i.e. temporarily place) the powder to be processed on the mesh frame 23. Fig. 3 is a cross-sectional view showing the structure of the supply unit 15 in Example 2. Fig. 3(a) shows the state at the time of setting, and Fig. 3(b) shows the state at the time of supplying powder. The supply unit 15 includes a hopper 26, a feeder 27, a squeegee 28, a mask 29, a support 30, a lifting mechanism 31, a suction pad 32, a base plate 33, and a linear motion mechanism 34.

[0028] The mask 29 is a plate material with an opening 100 provided in the center, and the opening 100 corresponds to the shape of the powder layer to be supplied onto the mesh frame 23. The material of the mask 29 is a plate material such as metal, ceramics, or resin. To prevent contamination of the powder, it is desirable to apply a fluororesin coat, PEEK coat, or DLC coat to the surface of the mask 29, or an anodizing process in the case of aluminum. The mask 29 is fixed to a base plate 33 via supports 30.

[0029] A predetermined amount of powder 35 is stored in the hopper 26. During the setting shown in Fig. 3(a), a predetermined amount of powder 35 in the hopper 26 is supplied by the feeder 27 to the space between the squeegee 28 and the mask 29. Meanwhile, the mesh frame 23 is placed on the lifting mechanism 31 by the mesh conveying mechanism 18 and fixed by the suction pad 32.

[0030] During powder supply as shown in FIG. 3(b), the mesh frame 23 is raised by the lifting mechanism 31 and abuts against the mask 29. After that, the base plate 33 is moved horizontally (to the right in the drawing) by the linear motion mechanism 34. At this time, the powder 35 supplied between the squeegee 28 and the mask 29 during setting is supplied onto the mesh frame 23. The powder supplied onto the mesh frame 23 is scraped off by the squeegee 28 and spread to the same thickness as the plate thickness of the mask 29. As a result, a powder layer of a size corresponding to the opening 100 of the mask 29 is formed on the mesh frame 23.

[0031] FIG. 4 is a top view showing an example of the shape of the opening of the mask 29 in the second embodiment. The simplest configuration of the mask 29 is one having one rectangular opening. A mask of this shape has the advantage that the amount of powder that can be processed in one classification process is larger than those of other shapes. The mask 29 in FIG. 4 has multiple openings 36. This allows multiple powder layers of the same size as the openings 36 to be formed on the mesh frame 23. In order to suck the powder during classification, it is necessary to form an air flow from the outside toward the suction housing. If the powder layer is a solid shape over the entire surface, the center of the powder layer cannot be sucked because there is no path for air to enter. In contrast, in this embodiment, a path for air to flow to the center of the mesh frame 23 can be formed, so the powder can be sucked over the entire surface.

[0032] Fig. 5 is a cross-sectional view showing the structure of the classification unit 16 in Example 2. Fig. 5(a) shows the state at the time of setting, and Fig. 5(b) shows the state at the time of classification. The classification unit 16 includes ultrasonic vibrators 37 and 43, a vibration plate 38, a lifting mechanism 39, a suction housing 40, and aperture plates 41 and 42.

[0033] Two aperture plates 41 and 42 are attached to the suction housing 40. The aperture plate is for flattening the shape of the mesh when the classification mesh 25 is pressed against the powder, and is a highly rigid plate with a plurality of apertures penetrating vertically for sucking the powder. In order to suppress the uneven suction caused by the opening position / non-opening position, it is desirable to make each opening small and arrange them at a high density to increase the opening rate, but this reduces the rigidity and may cause deformation when pressed. If the aperture plate deforms, the classification mesh will deform and the opening shape of the mesh will change, making it impossible to obtain the expected classification performance. In addition, when targeting materials with an average particle size of several μm to several tens of μm, such as electrode materials for lithium ion batteries, classification meshes with openings of 100 μm or less are often used, but such meshes are weak in strength and may break if the deformation is large. Therefore, by installing two aperture plates with different opening sizes and opening rates, both the suppression of uneven suction and rigidity are achieved. Compared with the aperture plate 41, the aperture size of the aperture plate 42 is made smaller and arranged at a higher density to increase the aperture ratio.

[0034] If it is desired to prevent metallic foreign matter from being mixed into the powder, it is desirable to form the aperture plates 41 and 42 and the suction housing 40 from resin, but if sufficient rigidity cannot be obtained, they may be formed from metal such as stainless steel or aluminum. In that case, it is desirable to form a non-metallic layer such as a resin coating such as fluororesin or a DLC coating on the area that comes into contact with the powder. Also, if sufficient rigidity is obtained with the aperture plate 42 alone, the aperture plate 41 may be made of a resin mesh such as nylon.

[0035] In this embodiment, an example has been described in which two aperture plates with different apertures are installed, but as long as it is possible to achieve both the flatness of the classification mesh and the suppression of uneven suction, a single aperture plate may be used.

[0036] During standby as shown in FIG. 5(a), the mesh frame 23 carrying the powder 35 is placed on the aperture plate 41 by the mesh transport mechanism 18 (not shown in FIG. 5).

[0037] During classification as shown in FIG. 5(b), the vibration plate 38 is lowered by the lifting mechanism 39, and the classification mesh 25 and the powder 35 are pressed against each other by the vibration plate 38 and the opening plates 41 and 42. Then, high-frequency power is applied to the ultrasonic transducer 37 to vibrate it. This causes the powder to fluidize, and particles smaller than the mesh size of the classification mesh 25 pass through the classification mesh 25. By applying vibration while pressing against the powder, even highly adhesive powder can be broken down into aggregates and fluidized. By simultaneously applying vibration and suction, the powder 35 that has passed through the classification mesh 25 is sucked and collected via the suction housing 40. In addition, by applying vibration at this time using the ultrasonic transducer 43 attached to the suction housing 40, the fluidization is further promoted, and the speed at which the powder passes through the classification mesh 25 is improved.

[0038] During classification, a control unit (not shown) controls the lifting mechanism 39 to adjust the height of the vibration plate 38 so as to follow the reduction in the powder layer thickness that accompanies the passage of the powder through the classification mesh 25. Alternatively, the vibration plate 38 may be made to follow the reduction by an elastic member such as a spring.

[0039] 6 is a cross-sectional view showing the structure of the mesh cleaning unit 17 in Example 2. The mesh cleaning unit 17 includes a suction nozzle 44, an air injection nozzle 45, a support column 46, a base plate 48, and a linear motion mechanism 49.

[0040] The mesh frame 23 is fixed to a support 46 by a suction pad 47. The support 46 is fixed to a base plate 48. The base plate 48 is fixed to a linear motion mechanism 49 and can be moved in the horizontal direction.

[0041] Air is sprayed onto the classification mesh 25 by the air spray nozzle 45, and any powder remaining on or clogging the classification mesh 25 is blown upward. The blown powder is sucked and collected by the suction nozzle 44. The mesh frame 23 is moved by the linear motion mechanism 49, so that the entire classification mesh 25 can be cleaned.

[0042] The mesh frame 23 cleaned in the mesh cleaning section 17 is introduced again into the supply section 15 by the mesh transport mechanism 18 (not shown in FIG. 6).

[0043] As described above, according to this embodiment, replacement of the classification mesh can be performed offline by removing the mesh frame 23 and reattaching the classification mesh, thereby improving the workability of mesh replacement. EXAMPLES

[0044] Example 3 will be described with reference to FIG. 7. FIG. 7 is a top view showing a schematic configuration of a classification device. Example 3 improves throughput by providing a vibration plate instead of a suction housing in the classification section described in Example 2 and applying vibration from above and below. Furthermore, a mesh cleaning mechanism is incorporated in the classification section to make the device more compact. The classification device in Example 3 includes a supply section 15, a classification section 50, a mesh transport mechanism 18, and a mesh frame 23. The supply section 15, the mesh transport mechanism 18, and the mesh frame 23 are the same as those in Example 2, and therefore will not be described.

[0045] Fig. 8 is a cross-sectional view showing the structure of the classification unit 50 in Example 3. Fig. 8(a) shows the state during setting, Fig. 8(b) shows the state during classification, and Fig. 8(c) shows the state during mesh-passed powder collection and mesh cleaning. The classification unit 50 includes an ultrasonic transducer 37, vibration plates 38a and 38b, a support 52, a space forming mesh 53, a lifting mechanism 54, a non-defective product suction nozzle 55, a linear motion mechanism 56, a residual product collection nozzle 57, and an air injection nozzle 58.

[0046] The ultrasonic transducer 37 is fixed to vibration plates 38a and 38b. The upper vibration plate 38a is fixed to a support 52. The lower vibration plate 38b is fixed to an elevation mechanism 54. A space forming mesh 53 is fixed on the lower vibration plate 38b.

[0047] The space forming mesh 53 is a mesh having a thickness obtained by using a wire having a large wire diameter, and forms a plurality of spaces for accommodating the powder that has passed through the classification mesh 25. The horizontal cross-sectional area of ​​each space of the space forming mesh 53 is larger than the cross-sectional area of ​​each opening of the classification mesh 25. In other words, the mesh opening of the space forming mesh 53 is larger than the mesh opening of the classification mesh 25. In addition, a plurality of space forming meshes 53 may be installed in layers depending on the volume of the powder that passes through the classification mesh 25. When it is desired to prevent the powder from being contaminated by metal foreign matter derived from the mesh, it is preferable to use a resin mesh such as nylon as the material for the space forming mesh 53.

[0048] The non-defective product suction nozzle 55 is for suctioning and recovering the classification mesh-passed powder accumulated in the space forming mesh 53 after classification, and is moved above the space forming mesh 53 while being sucked by a linear motion mechanism 56 .

[0049] The residual product recovery nozzle 57 and the air injection nozzle 58 are used to remove any powder that remains on or is clogged with the classification mesh 25, and are positioned in the direction in which the mesh frame 23 is transported by the mesh transport mechanism 18 (not shown in Figure 8).

[0050] During standby as shown in FIG. 8( a ), the mesh frame 23 carrying the powder 35 is placed on the space forming mesh 53 by the mesh transport mechanism 18 .

[0051] During classification as shown in Fig. 8(b), the lower vibration plate 38b is raised by the lifting mechanism 54, and the space forming mesh 53, the classification mesh 25, and the powder 35 are pressed against each other by the upper and lower vibration plates 38a, 38b. High-frequency power is then applied to the ultrasonic vibrator 37 to vibrate it. This causes the powder to become fluidized, and particles smaller than the mesh openings of the classification mesh 25 pass through the classification mesh 25. By applying vibrations while pressing against the powder, it is possible to break down agglomerations and fluidize even highly adhesive powder.

[0052] During mesh-passed powder recovery and mesh cleaning shown in Fig. 8(c), the non-defective product suction nozzle 55 moves to the right in the figure while sucking, and suction-recovers the classification mesh-passed powder accumulated in the space forming mesh 53. The mesh frame 23 is carried out to the right in the figure by the mesh transport mechanism 18. At this time, air is sprayed from the air spray nozzle 58 to blow powder remaining on the classification mesh 25 or that has become clogged upward. The blown powder is suction-recovered by the residual product recovery nozzle 57.

[0053] As described above, according to this embodiment, the classification throughput can be improved by applying vibration from above and below. Furthermore, the device can be made compact by incorporating a mesh cleaning mechanism in the classifying section. EXAMPLES

[0054] Example 4 will be described with reference to Figs. 9 to 12. In this example, a mesh conveying mechanism is not used, and a configuration based on a rotating plate is used to make the device compact. Fig. 9 is a cross-sectional view showing a schematic configuration of the classification device. As shown in Fig. 9, the classification device 1 includes a hopper 59, a feeder 60, base plates 61 and 76, an ultrasonic vibrator 64, a vibration plate 63, lifting mechanisms 62, 75 and 78, a rotating plate 65, a mesh frame 69, a classification mesh 70, a rotation mechanism 71, and a suction housing 72.

[0055] The ultrasonic transducer 64 is fixed to a vibration plate 63. The vibration plate 63 is fixed to a lifting mechanism 62. The lifting mechanism 62 is fixed to a base plate 61. The base plate 61 is fixed by a support 79.

[0056] 10 is a bottom view of the base plate 61. The base plate 61 includes a supply port 81, a squeegee plate 80, a suction nozzle 82, and a wall 68. The rotating plate 65 is fixed to a rotating mechanism 71 and rotates in the horizontal direction. The rotating mechanism 71 is fixed to a base plate 76.

[0057] FIG. 11 is a top view of the rotating plate 65. The rotating plate 65 includes an inner plate 66 and a wall 67. The mesh frame 69 is sandwiched and fixed between the rotating plate 65 and the inner plate 66. The classification mesh 70 is fixed to the mesh frame 69. The classification mesh 70 has an opening equal to or smaller than the lower limit of the size of the foreign particles to be removed and larger than the median particle size of the powder. Here, the opening of the classification mesh 70 can be larger than the size of the foreign particles, but if it is only slightly larger, the foreign particles can be substantially removed and the throughput can be improved, but if it is smaller than the size of the foreign particles, the removal can be ensured and reliability can be improved. If it is not desired to mix metal foreign particles into the powder, it is desirable to use a resin mesh such as nylon as the material of the classification mesh 70.

[0058] 12 is a top view of the base plate 76. The base plate 76 includes a wall 77 and an air injection nozzle 84. The base plate 76 is fixed to a lifting mechanism 78. The suction housing 72 is fixed to a lifting mechanism 75, which is fixed to the base plate 76.

[0059] Two aperture plates 73 and 74 are fixed to the upper opening of the suction housing 72 (the aperture plate 74 is hidden under the aperture plate 73 and cannot be seen in FIG. 12). The aperture plate is intended to flatten the shape of the mesh when the powder is pressed against the classification mesh 70, and is a highly rigid plate with multiple apertures penetrating vertically for sucking the powder. In order to suppress the uneven suction caused by the opening position / non-opening position, it is desirable to make each opening small and arrange them at a high density to increase the opening rate, but this reduces the rigidity and may cause deformation when pressed. If the aperture plate deforms, the classification mesh will deform and the opening shape of the mesh will change, making it impossible to obtain the expected classification performance. In addition, when targeting materials with an average particle size of several μm to several tens of μm, such as electrode materials for lithium ion batteries, classification meshes with openings of 100 μm or less are often used, but such meshes are weak in strength and may break if the deformation is large. Therefore, by installing two aperture plates with different opening sizes and opening rates, it is possible to achieve both suppression of uneven suction and rigidity. Compared with the aperture plate 74, the aperture size of the aperture plate 73 is made smaller and arranged at a higher density to increase the aperture ratio.

[0060] If it is desired to prevent metallic foreign matter from being mixed into the powder, it is desirable to form the opening plates 73 and 74 and the suction housing 72 from resin, but if sufficient rigidity cannot be obtained, they may be formed from a metal such as stainless steel or aluminum. In that case, it is desirable to form a non-metallic layer such as a resin coating such as fluororesin or a DLC coating on the area that comes into contact with the powder. Also, if sufficient rigidity is obtained with the opening plate 74 alone, the opening plate 73 may be made of a resin mesh such as nylon.

[0061] The operation of this device will be described. First, powder is put into the hopper 59. The rotation angle of the rotating plate 65 is set so that the classification mesh 70 is located under the supply port 81, and a predetermined amount of powder is supplied onto the classification mesh 70 by the feeder 60. The powder is stored in the space formed by the classification mesh 70, the squeegee plate 80, and the wall 67.

[0062] Thereafter, when the rotating plate 65 is rotated, the powder on the classification mesh 70 is scraped and spread by the squeegee plate 80, and a powder layer having the same thickness as the plate thickness of the inner plate 66 is formed on the classification mesh 70. The rotating plate 65 is rotated until the classification mesh 70 comes above the suction housing 72.

[0063] Then, the vibration plate 63 is lowered by the lifting mechanism 62, and the suction housing 72 is raised by the lifting mechanism 75, so that the powder and the classification mesh 70 are sandwiched and pressed between the vibration plate 63 and the opening plate 73. Then, while the suction housing 72 is being suctioned, the ultrasonic vibrator 64 applies vibration to the powder, and classification is performed. This causes the powder to become fluidized, and particles smaller than the mesh size of the classification mesh 70 pass through the classification mesh 70. By applying vibration while pressing against the powder, even highly adhesive powder can be broken down into agglomerates and fluidized. By simultaneously applying vibration and suction, the powder that has passed through the classification mesh 70 is sucked and collected via the suction housing 72. In addition, by applying vibration at this time using the ultrasonic vibrator 83 attached to the suction housing 72, the fluidization is further promoted, and the speed at which the powder passes through the classification mesh 70 is improved.

[0064] During classification, a control unit (not shown) controls the lifting mechanism 62 to adjust the height of the vibration plate 63 so that the vibration plate 63 can follow the reduction in the powder layer thickness that accompanies the passage of the powder through the classification mesh 70. Alternatively, the vibration plate 63 may be made to follow the reduction by an elastic member such as a spring.

[0065] After the classification is completed, the vibration plate 63 is raised by the lifting mechanism 62, the suction housing 72 is lowered by the lifting mechanism 75, and then the rotating plate 65 is rotated. At this time, air is sprayed from the air spray nozzle 84 (see FIG. 12) to blow powder remaining on the classification mesh 70 or clogged with it upwards. The blown powder is sucked and collected by the suction nozzle 82 (see FIG. 10).

[0066] As described above, according to this embodiment, a compact device configuration can be achieved without using a transport mechanism. In addition, since the inside of the powder processing area is almost completely closed off from the outside of the device by the walls 67, 68, and 77, there is also the advantage that there is little risk of contamination from the outside of the device. [Explanation of symbols]

[0067] 1...classification device, 2...feeder, 3, 25...classification mesh, 5, 10...ultrasonic vibrator, 6...vibration plate, 7, 40...suction housing, 8, 9, 41, 42...opening plate, 12...suction nozzle, 13...air injection nozzle, 14...roller, 15...supply section, 16, 50...classification section, 17...mesh cleaning section, 18...mesh transport mechanism, 23...mesh frame, 29...mask, 53...space forming mesh, 65...rotating plate.

Claims

1. A classification mesh for classifying powder; At least two pressing plates capable of pressing the classification mesh and the powder to be classified so as to sandwich them; A vibration mechanism that vibrates the pressing plate; A classification device comprising:

2. The classification device according to claim 1, At least one of the pressure plates has an opening, and the pressure plate is provided with a suction mechanism for sucking the powder classified by the classification mesh through the opening.

3. The classification device according to claim 2, a suction position for suctioning the powder classified by the suction mechanism, and a recovery position for recovering the powder not sucked by the suction mechanism; A classification device comprising a transport mechanism for transporting the classification mesh between the suction position and the recovery position.

4. The classification device according to claim 3, the conveying mechanism includes a rotating disk having an opening portion to which the classification mesh is fixed, A classification device comprising a mechanism for transporting the classification mesh between the suction position and the recovery position by rotating the rotating disk.

5. The classification device according to claim 3, A classification device characterized in that the classification mesh is provided on at least a part of a looped belt, and the conveying mechanism is a mechanism for rotating the belt with rollers.

6. The classification device according to claim 3, A classification device comprising: a holding member for holding the classification mesh; and the transport mechanism for transporting the holding member.

7. The classification device according to claim 3, A classification device comprising a cleaning position for cleaning the classification mesh on a transport path of the transport mechanism.

8. The classification device according to claim 1, A classification device comprising a mechanism for dividing the powder into a plurality of blocks and placing them on the classification mesh.

9. A method for classifying powder, comprising using the classification device according to any one of claims 1 to 8.

10. A powder supplying step of supplying powder to a classification mesh that classifies the powder; a powder pressing step of pressing the supplied powder and the classification mesh with at least two pressing plates so as to sandwich the powder and the classification mesh; a powder vibration step of vibrating the powder and the classification mesh; A method for classifying powder, comprising:

11. The method for classifying powder according to claim 10, a powder suction step of suctioning the powder classified by the powder vibration step; A method for classifying powder, comprising:

12. The method for classifying powder according to claim 11, a powder recovery step of recovering powder that has not been classified by the powder vibration step; A method for classifying powder, comprising:

13. The method for classifying powder according to claim 12, The powder suction step and the powder recovery step are performed at different positions, and a classification mesh transport step is performed to transport the classification mesh between the different positions; A method for classifying powder, comprising:

14. The method for classifying powder according to any one of claims 10 to 13, a cleaning step of cleaning the classification mesh; A method for classifying powder, comprising:

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