Classification apparatus and classification method

Abstract

A classifier (1) includes a casing (2), a rotary body (3), blades (4), a driving part (7), a control unit (8), a tubular member (9), and a bypass flow-path forming member (11). The casing (2) includes a tubular section (20). The rotary body (3) is disposed inside the tubular section (20), and the blades (4) rotate with the rotary body (3). The driving part (7) rotationally drives the rotary body (3). The control unit (8) controls the driving part (7). The tubular section (20) has a gas inlet (21), a gas outlet (22), and a particle discharging port (23). The tubular member (9) has: an internal space (90) communicating with the gas inlet (21); and a powder loading port (93) from which powder is loaded. The bypass flow-path forming member (11) has a bypass flow path (110) communicating with the gas inlet (21) and the gas outlet (22). The control unit (8) controls the rotation speed of the rotary body (3) to change the classification diameter of particles to be discharged from the particle discharging port (23).

Description

Technical Field

[0001] The present disclosure relates to a classification device and a classification method, and more particularly to a classification device and a classification method for classifying powder particles by utilizing a gas flow.

Background Art

[0002] Conventionally, as a classification mechanism, a classification mechanism and a classification method for separating fine powder and coarse powder by utilizing a swirling flow generated by the rotation of a classification rotor to obtain a product within a predetermined particle size range are known (Patent Document 1).

[0003] The classification mechanism disclosed in Patent Document 1 includes a main body casing, a classification rotor provided inside the main body casing, a single rotating shaft to which the classification rotor is attached, and a single drive source for rotationally driving the single rotating shaft.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In a classification device, improvement of classification efficiency is desired.

[0006] An object of the present disclosure is to provide a classification device and a classification method capable of improving classification efficiency.

[0007] A classification apparatus according to one aspect of the present disclosure comprises a casing, a rotating body, blades, a drive unit, and a control unit. The casing includes a cylindrical portion. The rotating body is disposed inside the cylindrical portion and is rotatable about a rotation axis along the axial direction of the cylindrical portion. The blades are disposed between the cylindrical portion and the rotating body and rotate together with the rotating body. The drive unit rotates the rotating body. The control unit controls the drive unit. The cylindrical portion has a gas inlet, a gas outlet located away from the gas inlet in the axial direction and connecting the inside and outside of the cylindrical portion, and a particle outlet. The classification apparatus further comprises a cylindrical member and a bypass flow path forming member. The cylindrical member has an internal space communicating with the gas inlet. The cylindrical member has a powder inlet into which powder having a particle size distribution is introduced. The bypass flow path forming member has a bypass flow path communicating with the gas inlet and the gas outlet. The control unit controls the rotation speed of the rotating body by controlling the drive unit, thereby changing the classification diameter of the particles discharged from the particle discharge port.

[0008] A classification method according to another aspect of the present disclosure classifies a powder using a classification apparatus. The classification apparatus comprises a casing, a rotating body, and blades. The casing includes a cylindrical portion having a circular inner circumference. The rotating body is disposed inside the cylindrical portion and is rotatable about an axis of rotation along the axial direction of the cylindrical portion. The blades are disposed between the cylindrical portion and the rotating body and rotate together with the rotating body. The classification method includes a first step and a second step. The first step involves rotating the rotating body at a first rotational speed to classify particles of a first classification diameter or larger from the powder. The second step involves rotating the rotating body at a second rotational speed higher than the first rotational speed after the first step to classify particles of a second classification diameter or larger, smaller than the first classification diameter, from the powder from which particles of a first classification diameter or larger were separated in the first step.

[0009] The classification apparatus and classification method described herein can improve classification efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a diagram showing the configuration of a classification apparatus according to Embodiment 1. [Figure 2] Figure 2 is a perspective view of the same classification apparatus. [Figure 3] Figure 3 is a cross-sectional view of the classification apparatus described above, including the rotating shaft. [Figure 4] Figure 4 is a cross-sectional view perpendicular to the rotation axis in the classification apparatus described above. [Figure 5] Figure 5 is a schematic diagram showing the classification apparatus described above with the first and second collection containers connected to it. [Figure 6] Figure 6 is a perspective view of the classification apparatus according to Embodiment 2. [Figure 7] Figure 7 is a schematic diagram showing the same classification apparatus with the particle discharge cylinder, first collection container, and second collection container connected to it. [Modes for carrying out the invention]

[0011] Figures 1 to 5 described in the embodiments below are schematic diagrams, and the size and thickness ratios of each component shown in the figures do not necessarily reflect the actual dimensional ratios.

[0012] (Embodiment 1) The classification device 1 according to Embodiment 1 will be described below with reference to Figures 1 to 5. Figure 1 is a configuration diagram of the classification device 1 according to Embodiment 1. It is a perspective view of the classification device 1. Figure 3 is a cross-sectional view of the classification device 1 including the rotating shaft 30. Figure 4 is a cross-sectional view of the classification device 1 perpendicular to the rotating shaft 30. Figure 5 is a schematic diagram of the classification device 1 in Embodiment 1 with the first collection container 140 and the second collection container 150 connected to it.

[0013] (1) Overview Classifier 1 classifies the powder. The powder has a particle size distribution. Not all particles in the powder are of uniform size; for example, particles of various sizes exist in various proportions within the range from the smallest particle size to the largest particle size.

[0014] As shown in Figures 1-4, the classifier 1 comprises a casing 2, a rotating body 3, blades 4, a drive unit 7, and a control unit 8. The casing 2 includes a cylindrical section 20 having a gas inlet 21, a gas outlet 22, and a particle outlet 23. The rotating body 3 is positioned inside the cylindrical section 20 and is rotatable about a rotation axis 30. The blades 4 are positioned between the rotating body 3 and the cylindrical section 20 and rotate together with the rotating body 3. In the classifier 1, the drive unit 7 rotates the rotating body 3. In other words, the drive unit 7 rotates the rotating body 3 about the rotation axis 30.

[0015] In the classification apparatus 1, a portion of the flow path from the gas inlet 21 to the gas outlet 22 is formed between the casing 2 and the rotating body 3. The particle outlet 23 is a hole for discharging relatively large particles from the powder to the outside of the casing 2.

[0016] The classifier 1 can move the air flowing into the gas inlet 21 of the cylindrical portion 20 of the casing 2 towards the gas outlet 22 while rotating it spirally around the rotating body 3. In the classifier 1, the air flowing into the flow path from the gas inlet 21 of the casing 2 is moved while rotating spirally around the rotating body 3 and can be moved towards the gas outlet 22. In the classifier 1, particles with relatively large particle sizes among the powder particles being conveyed by the airflow flowing into the casing 2 are discharged to the outside of the casing 2 from the particle outlet 23 while passing through the flow path. In Figure 1, particles with relatively large particle sizes among the particles contained in the powder are schematically shown as first particles P1, and particles with relatively small particle sizes are shown as second particles P2.

[0017] (2) Details As described above, the classifier 1 comprises a casing 2, a rotating body 3, blades 4, a drive unit 7, and a control unit 8. The classifier 1 further comprises a particle discharge cylinder 5. The classifier 1 further comprises an outlet cylinder 6. The classifier 1 further comprises a cylindrical member 9 and a bypass flow path forming member 11.

[0018] The material of the casing 2 is, for example, metal, but is not limited thereto, and may be resin (e.g., ABS resin). Further, the casing 2 may include a metal part formed of metal and a resin part formed of resin.

[0019] The casing 2 includes a cylindrical portion 20 having a circular inner peripheral shape. "Having a circular inner peripheral shape" means that the shape along the inner periphery of the cylindrical portion 20 is circular. The shape in the direction along the outer periphery of the cylindrical portion 20 is circular. The cylindrical portion 20 has a first end 201 and a second end 202 in the axial direction D1 of the cylindrical portion 20. The casing 2 includes the cylindrical portion 20 and a bottom portion 24 closing the opening of the second end 202 of the cylindrical portion 20. That is, in the classification device 1 according to the first embodiment, the casing 2 is a bottomed cylindrical shape. In the cylindrical portion 20, the opening of the first end 201 constitutes a gas inlet 21. Therefore, the gas inlet 21 penetrates in the axial direction D1 of the cylindrical portion 20.

[0020] In the cylindrical portion 20, the outer diameter of the first end 201 is smaller than the outer diameter of a portion 203 (hereinafter also referred to as a cylindrical portion 203) surrounding the rotating body 3 in the cylindrical portion 20. In the axial direction D1 of the cylindrical portion 20, the length of the cylindrical portion 203 is longer than the length of the rotating body 3. The inner diameter and the outer diameter of the cylindrical portion 203 are, for example, constant over the entire length in the axial direction D1 of the cylindrical portion 20, but are not limited thereto. For example, the inner diameter and the outer diameter of the cylindrical portion 203 may gradually decrease as they move away from the second end 202 of the cylindrical portion 20. Further, the cylindrical portion 20 includes a portion 204 (hereinafter also referred to as a diameter-expanded portion 204) between the first end 201 and the cylindrical portion 203, in which the inner diameter and the outer diameter gradually increase as they move away from the first end 201. The outer diameter of the diameter-expanded portion 204 is smaller than the inner diameter of the cylindrical portion 203. In the diameter-expanded portion 204, the opening area gradually increases as it moves away from the gas inlet 21 in the axial direction D1 of the cylindrical portion 20.

[0021] In the cylindrical portion 20, the gas outlet 22 is located away from the gas inlet 21 in the axial direction D1 of the cylindrical portion 20, and connects the inside and outside of the cylindrical portion 20 between the first end 201 and the second end 202 of the cylindrical portion 20. The gas outlet 22 is formed along one direction intersecting the axial direction D1 of the cylindrical portion 20 near the bottom 24 of the casing 2. In other words, the gas outlet 22 is open to the side of the cylindrical portion 20.

[0022] In the cylindrical portion 20, the particle outlet 23 is located away from the gas inlet 21 in the axial direction D1 of the cylindrical portion 20, and connects the inside and outside of the cylindrical portion 20 between the first end 201 and the second end 202 of the cylindrical portion 20. The particle outlet 23 is formed along one direction intersecting the axial direction D1 of the cylindrical portion 20 near the bottom 24 of the casing 2. In other words, the particle outlet 23 is open to the side of the cylindrical portion 20. The cylindrical portion 20 has a plurality of particle outlets 23 (for example, two). The two particle outlets 23 are separated in a direction along the outer circumference of the cylindrical portion 20. The two particle outlets 23 are aligned in one radial direction of the cylindrical portion 20 when viewed from the axial direction D1 of the cylindrical portion 20.

[0023] In the classification apparatus 1, along the outer circumference of the cylindrical section 20, the opening width of each of the multiple particle outlets 23 is shorter than the opening width of the gas outlet 22.

[0024] The rotating body 3 is positioned inside the cylindrical portion 20 and is rotatable about a rotation axis 30 along the axial direction D1 of the cylindrical portion 20. The rotating body 3 is connected, for example, to the rotation axis (shaft) of a motor included in the drive unit 7 via a shaft 71. The shaft 71 is round in shape. The material of the shaft 71 is, for example, stainless steel. The drive unit 7 is fixed to, for example, the casing 2. The shaft 71 is positioned so that its axis coincides with the rotation axis 30 of the rotating body 3.

[0025] The rotating body 3 is positioned coaxially with the cylindrical portion 20 inside the cylindrical portion 20. "Coaxially positioned with the cylindrical portion 20" means that the rotating body 3 is positioned so that its axis of rotation 30 is aligned with the central axis 29 of the cylindrical portion 20 (see Figure 3). The rotating body 3 is, for example, cylindrical, but is not limited to this. The rotating body 3 may be, for example, a bottomed cylindrical shape with a bottom wall on the gas inlet 21 side, or a frustoconical shape in which the outer diameter gradually increases as it moves away from the gas inlet 21 in the axial direction D1 of the cylindrical portion 20. If the rotating body 3 is a bottomed cylindrical shape, it is preferable that it has a reinforcing wall on the inside. The material of the rotating body 3 is, for example, ABS resin or polycarbonate resin.

[0026] The rotating body 3 has a first end 31 on the gas inlet 21 side and a second end 32 on the gas outlet 22 side. In the axial direction D1 of the cylindrical portion 20, the rotating body 3 is positioned near the enlarged diameter portion 204, rather than the enlarged diameter portion 204 and the bottom portion 24. More specifically, in the axial direction D1 of the cylindrical portion 20, the distance between the rotating body 3 and the enlarged diameter portion 204 is shorter than the distance between the rotating body 3 and the bottom portion 24.

[0027] The blades 4 are positioned between the cylindrical section 20 and the rotating body 3 and rotate together with the rotating body 3. In the classification device 1, multiple (in this case, 24) blades 4 are positioned between the cylindrical section 20 and the rotating body 3. In other words, the classification device 1 is equipped with multiple blades 4. The multiple blades 4 are connected to the rotating body 3 and are separated from the inner circumferential surface 26 of the cylindrical section 20. The multiple blades 4 rotate together with the rotating body 3.

[0028] Multiple blades 4 are provided on the rotating body 3 along its entire length in the direction of the axial direction D1 of the cylindrical portion 20. In other words, the multiple blades 4 are provided from the first end 31 to the second end 32 of the rotating body 3. The material of the multiple blades 4 is, for example, ABS resin or polycarbonate resin. In the classification device 1, the material of the rotating body 3 and the material of the multiple blades 4 are the same, but this is not limited to this, and they may be different. The multiple blades 4 may be formed integrally with the rotating body 3, or they may be formed as separate components from the rotating body 3 and connected to the rotating body 3 by being fixed to the rotating body 3.

[0029] Each of the multiple blades 4 is positioned such that a gap is formed between each blade 4 and the cylindrical portion 20 when viewed from the axial direction D1 of the cylindrical portion 20. In other words, in the classification device 1, there is a gap between each of the multiple blades 4 and the inner circumferential surface 26 of the cylindrical portion 20. In the radial direction of the rotating body 3, the distance between the protruding tip of each of the multiple blades 4 and the outer circumferential surface 36 of the rotating body 3 is shorter than the distance between the outer circumferential surface 36 of the rotating body 3 and the inner circumferential surface 26 of the cylindrical portion 20.

[0030] Each of the multiple blades 4 is positioned parallel to the rotation axis 30 of the rotating body 3 in the space (flow channel) between the outer circumferential surface 36 of the rotating body 3 and the inner circumferential surface 26 of the cylindrical portion 20. Each of the multiple blades 4 is flat. Each of the multiple blades 4 is a rectangular shape that is elongated in the direction along the rotation axis 30 of the rotating body 3 when viewed from the thickness direction. Each of the multiple blades 4 is inclined by a predetermined angle (for example, 45 degrees) with respect to one radial direction of the rotating body 3 when viewed from the bottom portion 24 side in the direction along the axial direction D1 of the cylindrical portion 20. In each of the multiple blades 4, the tip on the cylindrical portion 20 side in the direction of projection from the rotating body 3 is located behind the base end on the rotating body 3 side in the rotation direction R1 of the rotating body 3 (see Figure 4). In other words, in the classifier 1, each of the multiple blades 4 is inclined by a predetermined angle (for example, 45 degrees) with respect to one radial direction of the rotating body 3 in the rotation direction R1 of the rotating body 3. The predetermined angle is not limited to 45 degrees, but may be greater than 0 degrees and less than or equal to 90 degrees. For example, the predetermined angle may be an angle within the range of 10 degrees to 80 degrees. Each of the multiple blades 4 is not limited to being inclined by a predetermined angle with respect to one radial direction of the rotating body 3 in the direction of rotation R11 of the rotating body 3, but for example, the angle it makes with one radial direction of the rotating body 3 may be 0 degrees. In other words, the multiple blades 4 may extend radially from the rotating body 3. The multiple blades 4 are arranged at equal angular intervals along the outer circumference of the rotating body 3, as shown in Figure 4. The term "equal angular intervals" here is not limited to strictly identical angular intervals, but may be, for example, an angular interval within a predetermined error range (for example, ±10% of the specified angular interval) relative to a specified angular interval.

[0031] In the axial direction D1 of the cylindrical portion 20, the length of each of the multiple blades 4 is the same as the length of the rotating body 3. The length of each of the multiple blades 4 is not limited to being the same as the length of the rotating body 3; it may be longer or shorter than the rotating body 3.

[0032] In the axial direction D1 of the cylindrical portion 20, the length of each of the multiple blades 4 is shorter than the length of the cylindrical portion 203.

[0033] Each of the multiple blades 4 has a first end 41 on the gas inlet 21 side and a second end 42 on the gas outlet 22 and particle outlet 23 side in the axial direction D1 of the cylindrical portion 20.

[0034] The casing 2 has a space 25 on the particle outlet 23 side of the second end 42 of each blade 4 in the axial direction D1 of the cylindrical portion 20. In the classifier 1, the particle outlet 23 is located in a position that overlaps with the space 25 in a direction perpendicular to the rotation axis 30. In other words, the particle outlet 23 is located in a position that overlaps with the space 25 in a direction perpendicular to the axial direction D1 of the cylindrical portion 20. Also, in the classifier 1, the particle outlet 23 is located in a position that does not overlap with each blade 4 in a direction perpendicular to the rotation axis 30. In other words, the particle outlet 23 is located in a position that does not overlap with each blade 4 in a direction perpendicular to the axial direction D1 of the cylindrical portion 20. To put it another way, when the cylindrical portion 20 is viewed from the side, the projection area of ​​the particle outlet 23 does not contain any of the blades 4.

[0035] The drive unit 7 includes, for example, a motor that rotates the rotating body 3. The drive unit 7 has the motor's rotating shaft connected to the rotating body 3 via a shaft 71, but is not limited to this; the motor's rotating shaft may also be directly connected to the rotating body 3. The drive unit 7 may also be configured to transmit the rotation of the motor's rotating shaft to the rotating body 3 via a pulley and a rotating belt. The motor may be located inside the casing 2 or outside the casing 2. The rotational speed of the rotating body 3 rotated by the drive unit 7 is, for example, 1500 rpm to 3000 rpm.

[0036] The control unit 8 controls the drive unit 7. By controlling the drive unit 7, the control unit 8 controls the rotation speed of the rotating body 3, thereby changing the classification diameter of the particles discharged from the particle discharge port 23.

[0037] The control unit 8 includes a computer system. The computer system mainly consists of a processor and memory as hardware. The function of the control unit 8 is realized by the processor executing a program recorded in the computer system's memory. The program may be pre-recorded in the computer system's memory, provided via a telecommunications line, or provided on a non-temporary recording medium such as a memory card, optical disk, or hard disk drive that can be read by the computer system. The processor of the computer system consists of one or more electronic circuits including semiconductor integrated circuits (ICs) or large-scale integrated circuits (LSIs). The integrated circuits referred to here, such as ICs or LSIs, are named differently depending on the degree of integration, and include integrated circuits called system LSIs, VLSIs (Very Large Scale Integration), or ULSIs (Ultra Large Scale Integration). Furthermore, FPGAs (Field-Programmable Gate Arrays) that are programmed after the manufacture of the LSI, or logic devices that allow for the reconfiguration of junction relationships or circuit compartments within the LSI, can also be used as processors. Multiple electronic circuits may be integrated onto a single chip or distributed across multiple chips. Multiple chips may be integrated into a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller also consists of one or more electronic circuits, including semiconductor integrated circuits or large-scale integrated circuits.

[0038] As described above, the classifier 1 is equipped with a particle discharge cylinder 5. The particle discharge cylinder 5 is connected, for example, to the periphery of the particle discharge port 23 at the outer circumferential surface 27 of the cylinder 20. The particle discharge cylinder 5 is a component for discharging first particles P1, which are relatively large in size, from among the particles contained in the powder. The particle discharge cylinder 5 has an internal space 50 that communicates with the particle discharge port 23 and protrudes from the outer circumferential surface 27 of the cylinder 20. The particle discharge cylinder 5 is rectangular in shape. In addition, a part of the particle discharge cylinder 5 extends inward from the inner circumferential surface 26 of the cylinder 20. With respect to the portion of the particle discharge cylinder 5 that protrudes from the outer circumferential surface 27 of the cylinder 20, the opening on the side opposite to the particle discharge port 23 is rectangular in shape, with the longitudinal direction being along the axial direction D1 of the cylinder 20. Furthermore, in the particle discharge cylinder 5, with respect to the portion extending from the inner circumferential surface 26 of the cylinder 20, the opening on the side opposite to the particle discharge port 23 is rectangular in shape, with its longitudinal direction aligned with the axial direction D1 of the cylinder 20.

[0039] In the classification apparatus 1, as shown in Figure 4, the inner circumferential surface of the particle discharge port 23 in the cylindrical portion 20 has a rear inner surface 231 located rearward and a front inner surface 232 located forward in the direction along the rotation direction R1 of the rotating body 3. The rear inner surface 231 is formed along a tangential direction of the inner circumferential surface 26 of the cylindrical portion 20 when viewed from the axial direction D1 of the cylindrical portion 20. The particle discharge cylindrical portion 5 protrudes in the direction along the above tangential direction when viewed from the axial direction D1 of the cylindrical portion 20. The particle discharge cylindrical portion 5 is located in a position that does not overlap with the blades 4 in a direction perpendicular to the rotation axis 30. A part 53 of the particle discharge cylindrical portion 5 extends from the inner circumferential surface 26 of the cylindrical portion 20 along the front inner surface 232 of the particle discharge port 23 to a centerline B1 (see Figure 4) of the cylindrical portion 20. The above centerline B1 is perpendicular to the rotation axis 30 of the rotating body 3 and perpendicular to the axial direction of the particle discharge cylindrical portion 5. The classification apparatus 1 comprises a plurality of particle discharge cylinder sections 5 (for example, two). The plurality of particle discharge cylinder sections 5 are arranged to have rotational symmetry when viewed from the axial direction D1 of the cylinder section 20.

[0040] As shown in Figure 5, the classifier 1 may further include a first collection container 140 into which particles discharged through the particle discharge port 23 and the particle discharge cylinder 5 are collected. This allows the classifier 1 to collect first particles P1, which are relatively larger in size in the powder, into the first collection container 140.

[0041] Furthermore, the classification device 1 is equipped with an outlet cylinder 6 as described above. The outlet cylinder 6 is connected, for example, to the periphery of the gas outlet 22 on the outer circumferential surface 27 of the cylinder 20. The outlet cylinder 6 is a component for discharging the gas from which the first particles P1 have been separated to the outside of the casing 2. The outlet cylinder 6 has an internal space 60 that communicates with the gas outlet 22 and protrudes from the outer circumferential surface 27 of the cylinder 20. The outlet cylinder 6 is rectangular in shape. The outlet cylinder 6 has an inlet 61 on the gas outlet 22 side, an outlet 62 on the opposite side from the gas outlet 22, and an opening 63 that connects the internal space 60 of the outlet cylinder 6 with the bypass flow path 110 of the bypass flow path forming member 11. The opening 63 is located between the inlet 61 and the outlet 62, away from the inlet 61 and the outlet 62, and connects the inside and outside of the outlet cylinder 6.

[0042] In the classification apparatus 1, the outlet cylinder 6 is adjacent to one of the two particle discharge cylinders 5. The outlet cylinder 6 is located in front of the adjacent particle discharge cylinder 5 in the direction along the rotation direction R1 of the rotating body 3.

[0043] In the classification apparatus 1, the outlet cylinder 6 is arranged parallel to the adjacent particle discharge cylinder 5 when viewed from the axial direction D1 of the cylinder 20, but it is not limited to this arrangement; for example, it may protrude in a direction along a tangential direction of the inner circumferential surface 26 of the cylinder 20.

[0044] Furthermore, as shown in Figure 5, the classification device 1 may also include a second collection container 150 into which particles that have flowed out through the gas outlet 22 and the outlet cylinder 6 are collected. This allows the classification device 1 to collect second particles P2, which have a relatively small particle size in the powder, into the second collection container 150.

[0045] The classifier 1 includes a cylindrical member 9 as described above. The cylindrical member 9 has an internal space 90 that communicates with the gas inlet 21. The cylindrical member 9 has a powder inlet 93 into which powder is introduced. The cylindrical member 9 has a first end 91 connected to the first end 201 of the casing 2, and a second end 92 on the opposite side of the first end 91. The powder inlet 93 is formed in the cylindrical member 9 between the first end 91 and the second end 92, at a position away from the first end 91 and the second end 92. The classifier 1 further includes a powder inlet cylinder 10. The powder inlet cylinder 10 has an internal space that communicates with the powder inlet 93 and is connected to the cylindrical member 9. The powder inlet cylinder 10 is connected, for example, to the periphery of the powder inlet 93 on the outer circumferential surface of the cylindrical member 9. The powder inlet cylinder 10 may be, for example, a hopper. The classification device 1 further includes a shut-off section 160 that can open and close the powder inlet 93. The shut-off section 160 is a valve. This allows the powder inlet 93 to be closed by the shut-off section when powder is not being introduced. The shut-off section is controlled, for example, by a control unit 8. The shut-off section may also be a manually operated door.

[0046] Furthermore, the cylindrical member 9 has an opening 94 that connects the internal space 90 of the cylindrical member 9 with the bypass channel 110 of the bypass channel forming member 11. The opening 94 connects the inside and outside of the cylindrical member 9 at a position between the first end 91 of the cylindrical member 9 and the powder inlet 93, away from the first end 91 and the powder inlet 93.

[0047] The bypass channel forming member 11 is, for example, a duct. The bypass channel forming member 11 has a first end 111 on the gas outlet 22 side and a second end 112 on the gas inlet 21 side. The first end 111 of the bypass channel forming member 11 is connected to the periphery of the opening 63 of the outlet cylinder 6. The second end 112 of the bypass channel forming member 11 is connected to the periphery of the opening 94 of the cylindrical member 9. This allows the classifier 1 to generate an airflow through the gas inlet 21 and gas outlet 22 of the casing 2 and the bypass channel 110.

[0048] Furthermore, the classifier 1 further includes a switching unit 12. The switching unit 12 switches between a first state in the classifier 1 that utilizes the bypass flow path 110 and a second state that does not utilize the bypass flow path 110. The switching unit 12 switches between a first flow path that passes through the bypass flow path 110 and a second flow path that does not pass through the bypass flow path 110 as the flow path for the gas flowing out of the gas outlet 22 of the casing 2. The switching unit 12 switches between the first flow path and the second flow path, for example, under the control of a control unit 8. The switching unit 12 includes, for example, an opening / closing body 121. The opening / closing body 121 is, for example, located inside the outlet cylinder 6. The opening / closing body 121 is rotatable between a first position (shown by a solid line in Figure 1) in which it divides the internal space 60 of the outflow cylinder 6 into the space on the outlet 62 side of the outflow cylinder 6 and the spaces on the inlet 61 side and the opening 63 side without covering the opening 63, and a second position (shown by a dashed line in Figure 1) in which it covers the opening 63 of the outflow cylinder 6 and connects the outlet 62 of the outflow cylinder 6 with the gas outlet 22. In Figure 1, the rotation direction R2 of the opening / closing body 121 is indicated by an arrow.

[0049] Furthermore, the classification device 1 further includes a flow rate adjustment unit 13. The flow rate adjustment unit 13 adjusts, for example, the flow rate of gas passing through the gas inlet 21. The flow rate adjustment unit 13 is located, for example, in the internal space 90 of the cylindrical member 9, on the side of the first end 91 of the cylindrical member 9 that is closer to the powder inlet 93. The flow rate adjustment unit 13 is controlled, for example, by a control unit 8, to adjust the flow rate of gas passing through the gas inlet 21 when the rotating body 3 and the blades 4 are rotating. In the classification device 1, the control unit 8 controls the flow rate adjustment unit 13 so that, for example, the flow rate of the gas inlet 21 remains substantially constant even when the rotation speed of the rotating body 3 is changed. This makes it possible for the classification device 1 to suppress the decrease in classification efficiency caused by an increase in flow velocity due to an increase in the flow rate of the gas inlet 21 when the rotation speed of the rotating body 3 is relatively increased. The flow rate adjustment unit 13 includes, for example, a valve. The valve is a butterfly valve, but is not limited to this, and may be a ball valve, for example. In the classification device 1, the flow rate adjustment unit 13 is located in the internal space 90 of the cylindrical member 9 on the side of the first end 91 of the cylindrical member 9 that is closer to the powder inlet 93, thereby suppressing collisions of powder particles with the flow rate adjustment unit 13.

[0050] Furthermore, the classification device 1 is further equipped with an air filter 14 located inside the cylindrical member 9 at the first end 91 of the cylindrical member 9. The air filter 14 is a filter for removing foreign matter (e.g., dust, dirt, particles, etc.) contained in the outside air that is drawn in through the opening at the first end 91 of the cylindrical member 9 when the rotating body 3 and the blades 4 are rotated in the classification device 1. In Figure 1, the flow of outside air is schematically shown by the outlined arrow F1.

[0051] (3) Operation of the classification device In the classification apparatus 1 according to Embodiment 1, the rotation direction R1 (see Figure 4) of the rotating body 3 is, for example, clockwise when the rotating body 3 is viewed from the bottom 24 side of the casing 2 in the axial direction D1 of the cylindrical portion 20. The classification apparatus 1 rotates the rotating body 3 with a drive unit 7.

[0052] In the classifier 1, as the rotating body 3 rotates, multiple blades 4 rotate together with the rotating body 3, and the velocity vector of the air flowing in the inner space of the casing 2 has a velocity component in the direction parallel to the rotation axis 30 and a velocity component in the rotational direction around the rotation axis 30. In short, in the classifier 1, the rotation of the rotating body 3 and each blade 4 generates a swirling airflow within the casing 2. The swirling airflow is a three-dimensional spiral rotating airflow.

[0053] In the classification device 1, a swirling airflow (swirling flow) is generated in the inner space of the casing 2. As a result, some of the air particles that flow into the casing 2 from the gas inlet 21 of the cylindrical section 20 are discharged through the particle outlet 23 and the particle discharge cylinder 5, and some of the air containing the remaining particles flows out from the gas outlet 22 of the cylindrical section 20.

[0054] In the classification device 1, particles contained in the air flowing into the casing 2 are subjected to centrifugal force directed from the rotation axis 30 of the rotating body 3 toward the inner surface 26 of the cylindrical section 20 as they rotate spirally within the inner space of the casing 2. The particles subjected to centrifugal force are moved toward the inner surface 26 of the cylindrical section 20 and tend to rotate spirally along the inner surface 26 near the inner surface 26 of the cylindrical section 20. Then, in the classification device 1, some of the particles in the air are discharged from the particle discharge cylinder 5 through the particle discharge port 23 while passing through the inner space of the casing 2. The centrifugal force acting on the particles is proportional to the mass of the particles. Therefore, particles with relatively larger mass are more likely to reach the vicinity of the inner surface 26 of the cylindrical section 20 earlier than particles with relatively smaller mass.

[0055] Furthermore, the centrifugal force acting on a particle is proportional to the particle's mass and the radius of its circular motion. The radius of the circular motion is the distance between the axis of rotation 30 and the particle in a direction perpendicular to the axis of rotation 30 of the rotating body 3. If the particle's mass is m, its velocity is v, and its radius of circular motion is r, then the magnitude of the centrifugal force is mv 2 / r. Here, if we let the angular velocity be ω, then v = rω, so the magnitude of the centrifugal force is mω 2 r. In short, a centrifugal force proportional to the square of ω acts on the particle. Therefore, the magnitude of the centrifugal force acting on the particle can be changed by changing the rotational speed of the rotating body 3. Also, if the rotational speed of the rotating body 3 is the same, particles with a larger mass are more likely to reach the vicinity of the inner circumferential surface 26 of the cylindrical portion 20 before particles with a smaller mass.

[0056] In the classifier 1, as the rotation speed of the rotating body 3 increases, there is a tendency for smaller particles to be discharged more easily from the particle discharge port 23. Regarding powder particles, if the particle density is the same, the smaller the particle mass, the smaller the particle size.

[0057] In the classification device 1, the control unit 8 controls the rotation speed of the rotating body 3 by controlling the drive unit 7, thereby changing the classification diameter of the particles discharged from the particle discharge port 23.

[0058] In the classifier 1, when the rotating body 3 and blades 4 are rotated and the bypass channel 110 is in use, and powder is introduced from the powder inlet 93, an airflow containing first particles P1 larger than the classification diameter and second particles P2 smaller than the classification diameter is circulated through the bypass channel 110. This makes it easier for the first particles P1 to be discharged from the particle outlet 23, thereby improving the classification efficiency.

[0059] In the classifier 1, the control unit 8 controls the rotation speed of the rotating body 3 according to the classification diameter of the particles to be discharged from the particle outlet 23, for example. In the classifier 1, the particles that remain in the air without being discharged from the particle outlet 23 include particles with a particle size smaller than the classification diameter.

[0060] (4) Advantages The classification apparatus 1 according to Embodiment 1 comprises a casing 2, a rotating body 3, blades 4, a drive unit 7, and a control unit 8. The casing 2 includes a cylindrical portion 20 having a circular inner circumference. The rotating body 3 is positioned inside the cylindrical portion 20 and is rotatable about a rotation axis 30 along the axial direction D1 of the cylindrical portion 20. The blades 4 are positioned between the cylindrical portion 20 and the rotating body 3 and rotate together with the rotating body 3. The drive unit 7 rotates the rotating body 3. The control unit 8 controls the drive unit 7. The cylindrical portion 20 has a gas inlet 21, a gas outlet 22 that is separated from the gas inlet 21 in the axial direction D1 and connects the inside and outside of the cylindrical portion 20, and a particle outlet 23. The classification apparatus 1 further comprises a cylindrical member 9 and a bypass flow path forming member 11. The cylindrical member 9 has an internal space that communicates with the gas inlet 21. The cylindrical member 9 has a powder inlet 93 into which powder having a particle size distribution is introduced. The bypass channel forming member 11 has a bypass channel 110 which is formed by an internal space communicating with a gas inlet 21 and a gas outlet 22. The control unit 8 controls the rotation speed of the rotating body 3 by controlling the drive unit 7, thereby changing the classification diameter of the particles discharged from the particle outlet 23.

[0061] With the above configuration, the classification apparatus 1 according to Embodiment 1 can improve the classification efficiency.

[0062] Furthermore, the classification device 1 according to Embodiment 1 includes a rotating body 3 and blades 4 that rotate together with the rotating body 3, and the outlet cylinder portion 6 protrudes in a direction along a tangential direction to the outer circumferential surface 27 of the cylinder portion 20, making it possible to reduce pressure loss.

[0063] Furthermore, the classification apparatus 1 according to Embodiment 1 includes a rotating body 3 and blades 4 that rotate together with the rotating body 3, and the outlet cylinder portion 6 protrudes in a direction along one tangential direction to the outer peripheral surface 27 of the cylinder portion 20. Therefore, for example, by designing the outlet cylinder portion 6 so that the pressure at the gas outlet 22 is higher than the pressure at the gas inlet 21, it is possible to eliminate the need to separately provide a blower for generating an airflow to transport the powder.

[0064] (Embodiment 2) The classification apparatus 1a according to Embodiment 2 will be described below with reference to Figures 6 and 7. Figure 6 is a perspective view of the classification apparatus 1a according to Embodiment 2. Figure 7 is a schematic diagram of the classification apparatus 1a according to Embodiment 2 with the particle discharge cylinder 5, the first collection container 140, and the second collection container 150 connected.

[0065] The classifier 1a according to Embodiment 2 is substantially the same as the classifier 1 according to Embodiment 1 (see Figure 1), except that the cylindrical portion 20 has a plurality of particle discharge ports 23 that are spaced apart from each other in the axial direction D1 of the cylindrical portion 20. With respect to the classifier 1a according to Embodiment 2, components that are the same as those in the classifier 1 according to Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted. Note that in Figure 6, the bypass flow path forming member 11, switching unit 12, cylindrical member 9 and control unit 8, etc., as shown in Figure 1 are omitted.

[0066] Each of the multiple particle outlets 23 is a long slit in the direction along the outer circumference of the cylindrical portion 20. Each of the multiple particle outlets 23 is arc-shaped when viewed from the direction along the axial direction D1 of the cylindrical portion 20. The classifier 1a may be provided with multiple particle discharge cylinders 5 that correspond one-to-one with the multiple particle outlets 23, as shown in Figure 7. As shown in Figure 7, the classifier 1a may be provided with a first collection container 140 for each set of particle outlets 23 and particle discharge cylinders that correspond one-to-one, similar to the classifier 1, for particles discharged through the particle outlets 23 and particle discharge cylinders. Also, as shown in Figure 7, the classifier 1a may further be provided with a second collection container 150 for particles that have flowed out through the gas outlet 22 and the outlet cylinder 6, similar to the classifier 1.

[0067] In the following explanation, for convenience, the multiple particle outlets 23 that are separated from each other in the axial direction D1 of the cylindrical portion 20 may be referred to as the first particle outlet 23A, the second particle outlet 23B, the third particle outlet 23C, and the fourth particle outlet 23D, in order from closest to the gas inlet 21.

[0068] The classifier 1a further comprises a first opening / closing unit for opening and closing a first particle outlet 23A, a second opening / closing unit for opening and closing a second particle outlet 23B, a third opening / closing unit for opening and closing a third particle outlet 23C, and a fourth opening / closing unit for opening and closing a fourth particle outlet 23D. The control unit 8 exclusively controls the first opening / closing unit, the second opening / closing unit, the third opening / closing unit, and the fourth opening / closing unit. "Exclusively controlling" means controlling one of the first opening / closing unit, the second opening / closing unit, the third opening / closing unit, and the fourth opening / closing unit to open the particle outlet 23 corresponding to that unit, and controlling each of the remaining three opening / closing units to close the corresponding particle outlet 23. Therefore, the control unit 8 performs a first control operation on the set of the first, second, third, and fourth opening / closing parts, for example, to open the first particle outlet 23A and close the second particle outlet 23B, the third particle outlet 23C, and the fourth particle outlet 23D. The control unit 8 also performs a second control operation on the set of the first, second, third, and fourth opening / closing parts, for example, to open the second particle outlet 23B and close the first particle outlet 23A, the third particle outlet 23C, and the fourth particle outlet 23D. The control unit 8 also performs a third control operation on the set of the first, second, third, and fourth opening / closing parts, for example, to open the third particle outlet 23C and close the first particle outlet 23A, the second particle outlet 23B, and the fourth particle outlet 23D. Furthermore, the control unit 8 performs a fourth control operation on the set of the first, second, third, and fourth opening / closing sections, for example, by opening the fourth particle outlet 23D and closing the first particle outlet 23A, the second particle outlet 23B, and the third particle outlet 23C.

[0069] Furthermore, the control unit 8 makes the rotational speed of the rotating body 3 different for each of the first, second, third, and fourth control operations. When the control unit 8 performs the first control operation on the set, it controls the drive unit 7 to rotate the rotating body 3 at the first rotational speed. When the control unit 8 performs the second control operation on the set, it controls the drive unit 7 to rotate the rotating body 3 at the second rotational speed, which is higher than the first rotational speed. When the control unit 8 performs the third control operation on the set, it controls the drive unit 7 to rotate the rotating body 3 at the third rotational speed, which is higher than the second rotational speed. When the control unit 8 performs the fourth control operation on the set, it controls the drive unit 7 to rotate the rotating body 3 at the fourth rotational speed, which is higher than the third rotational speed.

[0070] The first rotation speed mentioned above is predetermined, for example, according to the first classification diameter. The first classification diameter is the threshold particle size of the particles discharged from the first particle outlet 23A.

[0071] The second rotation speed is predetermined, for example, according to a second classification diameter that is smaller than the first classification diameter. The second classification diameter is the threshold particle size of the particles discharged from the second particle outlet 23B.

[0072] The third rotation speed is predetermined, for example, according to a third classification diameter that is smaller than the second classification diameter. The third classification diameter is the threshold particle size of the particles discharged from the third particle outlet 23C.

[0073] The fourth rotation speed is predetermined, for example, according to a fourth classification diameter that is smaller than the third classification diameter. The fourth classification diameter is the threshold particle size of the particles discharged from the fourth particle outlet 23D.

[0074] The classification device 1a according to Embodiment 2 is equipped with a bypass flow path forming member 11 (see Figure 1), similar to the classification device 1 according to Embodiment 1, making it possible to improve the classification efficiency.

[0075] The classification method according to Embodiment 2 classifies powder using a classification device 1a. The classification device 1a comprises a casing 2, a rotating body 3, and blades 4. The casing 2 includes a cylindrical portion 20 having a circular inner circumference. The rotating body 3 is positioned inside the cylindrical portion 20 and is rotatable about a rotation axis 30 along the axial direction D1 of the cylindrical portion 20. The blades 4 are positioned between the cylindrical portion 20 and the rotating body 3 and rotate together with the rotating body 3. The classification method includes, for example, a first step, a second step, a third step, and a fourth step. In the classification method, the rotating body 3 and blades 4 are rotated without covering the opening 63 of the outlet cylindrical portion 6 with the opening / closing body 121 of the switching unit 12, but this is not limited to this. In other words, the classification method sets the classification device 1 to a first state that utilizes the bypass flow path 110, but this is not limited to this, and the classification device 1 may also be set to a second state that does not utilize the bypass flow path 110.

[0076] The first step involves rotating the rotating body 3 at a first rotational speed to classify particles larger than or equal to the first classification diameter from the powder. In the first step, the control unit 8 performs a first control operation on the above set, and then rotates the rotating body 3 at the first rotational speed. Also in the first step, with the rotating body 3 rotating at the first rotational speed, the powder inlet 93 is opened and the powder is introduced through the powder inlet 93. The powder inlet 93 is closed when not introducing powder.

[0077] In the second step, after the first step, the rotating body 3 is rotated at a second rotational speed higher than the first rotational speed, and particles with a second classification diameter or larger (smaller than the first classification diameter) are classified from the powder from which particles with a first classification diameter or larger were separated in the first step. In the second step, the control unit 8 performs a second control operation on the above set, and then rotates the rotating body 3 at the second rotational speed.

[0078] In the third step, after the second step, the rotating body 3 is rotated at a third rotational speed higher than the second rotational speed, and particles with a third classification diameter or larger (smaller than the second classification diameter) are classified from the powder from which particles with a second classification diameter or larger were separated in the second step. In the third step, the control unit 8 performs a third control operation on the above set, and then rotates the rotating body 3 at the third rotational speed.

[0079] In the fourth step, after the third step, the rotating body 3 is rotated at a fourth rotational speed higher than the third rotational speed, and particles with a fourth classification diameter or larger, which are smaller than the third classification diameter, are classified from the powder from which particles with a third classification diameter or larger were separated in the third step. In the fourth step, the control unit 8 performs a fourth control operation on the above set, and then rotates the rotating body 3 at the fourth rotational speed.

[0080] The classification method according to Embodiment 2 can improve classification efficiency. Furthermore, the classification method according to Embodiment 2 can improve classification accuracy.

[0081] The classification method according to Embodiment 2 only needs to include at least the first and second steps among the first to fourth steps.

[0082] (modified version) Each of Embodiments 1 and 2 is merely one of many embodiments of this disclosure. Embodiments 1 and 2 can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved.

[0083] For example, the cylindrical section 20 in the classification device 1 may have multiple gas outlets 22. In this case, the classification device 1 may have multiple outlet cylindrical sections 6.

[0084] Furthermore, in the classification apparatus 1 according to Embodiment 1, the gas inlet 21 penetrates the cylindrical portion 20 in the axial direction D1 (the surface including the gas inlet 21 intersects the axial direction D1), but it is not limited to this, and the surface including the gas inlet 21 may intersect in a direction perpendicular to the axial direction D1 of the cylindrical portion 20.

[0085] Furthermore, in the classification device 1, the number of particle discharge ports 23 in the cylindrical section 20 is not limited to multiple ports, but may be just one.

[0086] Furthermore, the shapes of the multiple particle outlets 23 are not limited to being the same as each other; they may be different.

[0087] Furthermore, the tip of each of the multiple blades 4 on the cylindrical portion 20 side in the direction of projection from the rotating body 3 may be located in front of the base end on the rotating body 3 side in the rotational direction R1 of the rotating body 3.

[0088] Furthermore, each of the multiple blades 4 may have a shape that includes one or more curved parts, such as arcs.

[0089] Furthermore, each of the multiple blades 4 may be formed in a spiral shape around the rotation axis 30 of the rotating body 3. Here, "spiral shape" is not limited to a spiral shape with 1 or more rotations, but also includes a part of a spiral shape with 1 rotation.

[0090] The switching section 12 is not limited to a configuration including one opening / closing body 121, but may also include a first gate valve that opens and closes the space between the inlet 61 and outlet 62 of the outflow pipe section 6, and a second gate valve that opens and closes the opening at the first end 111 of the bypass flow path forming member 11.

[0091] The flow rate adjustment unit 13 is not limited to a configuration that adjusts the flow rate of the gas inlet 21, for example, but may also be configured to adjust the flow rate of the gas outlet 22.

[0092] (Aspect) This specification discloses the following aspects:

[0093] A classification apparatus according to the first embodiment (1; 1a) comprises a casing (2), a rotating body (3), blades (4), a drive unit (7), and a control unit (8). The casing (2) includes a cylindrical portion (20). The rotating body (3) is located inside the cylindrical portion (20) and is rotatable about a rotation axis (30) along the axial direction (D1) of the cylindrical portion (20). The blades (4) are located between the cylindrical portion (20) and the rotating body (3) and rotate together with the rotating body (3). The drive unit (7) rotates the rotating body (3). The control unit (8) controls the drive unit (7). The cylindrical section (20) has a gas inlet (21), a gas outlet (22) that is separated from the gas inlet (21) in the axial direction (D1) and connects the inside and outside of the cylindrical section (20), and a particle outlet (23). The classification device (1) further comprises a cylindrical member (9) and a bypass channel forming member (11). The cylindrical member (9) has an internal space (90) that communicates with the gas inlet (21). The cylindrical member (9) has a powder inlet (93) into which powder having a particle size distribution is introduced. The bypass channel forming member (11) has a bypass channel (110) that communicates with the gas inlet (21) and the gas outlet (22). The control unit (8) controls the rotation speed of the rotating body (3) by controlling the drive unit (7) to change the classification diameter of the particles discharged from the particle outlet (23).

[0094] The classification apparatus (1;1a) according to the first embodiment makes it possible to improve the classification efficiency.

[0095] The classification apparatus (1;1a) according to the second embodiment further comprises a flow rate adjustment unit (13) for adjusting the flow rate of a gas inlet (21) or a gas outlet (22) as in the first embodiment.

[0096] The classification apparatus (1;1a) according to the second embodiment makes it possible to suppress the decrease in classification efficiency when the rotational speed of the rotating body (3) is increased.

[0097] A classification apparatus according to a third embodiment (1;1a) further comprises a particle discharge cylinder (5) in the first or second embodiment. The particle discharge cylinder (5) has an internal space (50) that communicates with the particle discharge port (23) and protrudes from the outer circumferential surface (27) of the cylinder (20). When viewed from the axial direction (D1) of the cylinder (20), the particle discharge cylinder (5) protrudes in a direction along one tangential direction of the inner circumferential surface (26) of the cylinder (20).

[0098] In the third embodiment of the classification apparatus (1;1a), particles passing near the particle discharge port (23) are more easily discharged through the particle discharge port (23) and the particle discharge cylinder (5).

[0099] The classification device (1;1a) according to the fourth embodiment further comprises a switching unit (12) that switches between a first state in which the bypass flow path (110) is used and a second state in which the bypass flow path (110) is not used in any one of the first to third embodiments.

[0100] The classification apparatus according to the fifth embodiment (1;1a) further comprises an outlet cylinder (6) in the fourth embodiment. The switching unit (12) includes an opening / closing body (121). The outlet cylinder (6) has an internal space (60) that communicates with the gas outlet (22) and protrudes from the outer circumferential surface (27) of the cylinder (20). The opening / closing body (121) is located inside the outlet cylinder (6). The outlet cylinder (6) has an inlet (61) on the gas outlet (22) side, an outlet (62) on the opposite side from the gas outlet (22), and an opening (63) that connects the internal space (60) of the outlet cylinder (6) with the bypass flow path (110) of the bypass flow path forming member (11). The opening / closing body (121) is rotatable between a first position in which it does not cover the opening (63) and divides the internal space (60) of the outflow cylinder (6) into the space on the outlet (62) side of the outflow cylinder (6) and the spaces on the inlet (61) side and the opening (63) side, and a second position in which it covers the opening (63) and connects the outlet (62) of the outflow cylinder (6) with the gas outlet (22).

[0101] A classification method according to the sixth embodiment classifies a powder using a classification device (1a). The classification device (1a) comprises a casing (2), a rotating body (3), and blades (4). The casing (2) includes a cylindrical portion (20) having a circular inner circumference. The rotating body (3) is positioned inside the cylindrical portion (20) and is rotatable about a rotation axis (30) along the axial direction (D1) of the cylindrical portion (20). The blades (4) are positioned between the cylindrical portion (20) and the rotating body (3) and rotate together with the rotating body (3). The classification method includes a first step and a second step. The first step involves rotating the rotating body (3) at a first rotational speed to classify particles of a first classification diameter or larger from the powder. In the second step, after the first step, the rotating body (3) is rotated at a second rotational speed higher than the first rotational speed, and particles with a second classification diameter or larger, which are smaller than the first classification diameter, are classified from the powder from which particles with a first classification diameter or larger were separated in the first step.

[0102] The classification method according to the sixth embodiment makes it possible to improve classification efficiency. [Industrial applicability]

[0103] The classification apparatus and classification method of this disclosure can improve classification efficiency. In other words, the classification apparatus and classification method of this disclosure can efficiently classify powders and are industrially useful. [Explanation of symbols]

[0104] 1, 1a Classifier 2 Casing 20 Cylinder part 201 1st end 202 2nd end 21 Gas inlet 22 Gas outlet 23 Particle outlet 23A 1st particle outlet 23B 2nd particle outlet 23C 3rd particle outlet 23D 4th particle outlet 3. Rotating bodies 30 Rotation axis 31 1st end 32 2nd end 4 feathers 41 1st end 42 2nd end 5 Particle discharge tube section 50 Interior space 6 Outflow cylinder part 60 Interior space 61 Entrance 62 Exit 63 Aperture 7 Drive Unit 8 Control Unit 9. Cylindrical member 90 Interior space 91 1st end 92 2nd end 93 Powder inlet 94 Aperture 11 Bypass channel forming member 110 Bypass channel 111 1st end 112 2nd end 12 Switching section 121 Opening / Closing Mechanism 13 Flow rate adjustment section D1 Axial direction P1 1st particle P2 2nd particle R1, R2 rotation direction

Claims

1. A casing including a cylindrical portion, A rotating body is positioned inside the cylindrical portion and is rotatable about a rotation axis positioned along the axial direction of the cylindrical portion, A vane is positioned between the cylindrical portion and the rotating body and rotates together with the rotating body, A drive unit that rotates the aforementioned rotating body, The system comprises a control unit for controlling the drive unit, The cylindrical portion is Gas inlet and A gas outlet is positioned away from the gas inlet along the axial direction and connects the inside and outside of the cylindrical portion, In a classification apparatus having a particle discharge port, A cylindrical member having an internal space communicating with the aforementioned gas inlet and a powder inlet into which powder having a particle size distribution is introduced, The system further comprises a bypass channel forming member having a bypass channel that communicates with the gas inlet and the gas outlet, The control unit controls the rotation speed of the rotating body to change the classification diameter of the particles discharged from the particle discharge port, The system further includes a switching unit that switches between a first state in which the bypass channel is used and a second state in which the bypass channel is not used. The system further comprises an outlet cylinder having an internal space that communicates with the gas outlet and protruding from the outer surface of the cylindrical portion, The aforementioned outlet pipe section is The inlet on the gas outlet side, The outlet on the opposite side from the aforementioned gas outlet side, It has an opening that connects the internal space of the outlet pipe portion with the bypass channel of the bypass channel forming member, The switching section includes an opening / closing body located within the outlet cylinder section. The opening and closing body is It is rotatable between a first position in which the internal space of the outflow cylinder is divided into the space on the outlet side of the outflow cylinder and the spaces on the inlet side and the opening side without covering the opening, and a second position in which the opening is covered and the outlet of the outflow cylinder is connected to the gas outlet. Classifying device.

2. The system further includes a flow rate adjustment unit for adjusting the flow rate of the gas inlet or gas outlet. The classification apparatus according to claim 1.

3. It further includes a particle discharge cylinder section, The particle discharge cylinder portion has an internal space that communicates with the particle discharge port and protrudes from the outer circumferential surface of the cylinder portion, and when viewed from the axial direction, it protrudes in a direction along one tangential direction to the inner circumferential surface of the cylinder portion. The classification apparatus according to claim 1.

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