JP2014057909A - Powder classifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance accuracy of classification by performing reliable distributed processing to a raw material powder, in powder classifying processing for classifying the raw material powder conveyed in a mixed state with gas into several kinds of powder, according to a size or density (or specific density) of the powder.SOLUTION: A powder classifying device classifies a raw material powder in a mixed state with gas, which is supplied in a flow path having a flow path cross section of a fixed width in a longitudinal direction, into a first powder and a second powder using inertial force. The powder classifying device includes a dispersion part for pulverizing or dispersing a raw material powder, and a classification part disposed adjacent to the dispersion part and classifying the raw material powder pulverized or dispersed in the dispersion part into the first powder and the second powder. The dispersion part is a choke portion of the flow path in which a fixed width of the flow path cross section is continuously reduced toward the downstream side and then is increased.

Description

  The present invention is a powder that classifies a raw material powder into a plurality of types of powder by separating the raw material powder conveyed in a mixed state with a gas according to the size or density (or specific gravity) of the powder. It relates to a classification device.

  Conventionally, various types of powder classifiers that mix and transport raw material powder having a particle size distribution into gas and classify it into multiple types of powder according to the size or density of the powder It has been known. For example, in a powder classification apparatus that classifies raw material powder into fine powder and coarse powder, so-called fine powder including, for example, powder having a particle size distribution on the order of microns is handled as raw material powder.

  In such a conventional powder classifying apparatus, a powder classifying apparatus that employs a rectangular channel cross section having a certain width in the longitudinal direction as a raw material powder channel is known (for example, see Non-Patent Document 1). . In the powder classifying device of Non-Patent Document 1, clean air channels are arranged adjacent to each side of the raw material powder channel having a rectangular channel cross section so that the raw material powder channel and four clean air channels are arranged. A configuration is adopted in which the flow of the raw material powder is surrounded by clean air in the portion where the raw material powder is classified after joining the flow path. By adopting such a configuration, it is possible to suppress the flow of the raw material powder from directly contacting the flow path wall surface in the classification portion, and it is possible to suppress the adhesion / deposition of the powder to the wall surface.

  In addition, a powder classification device has been proposed that employs an annular channel cross section having a constant width in the circumferential direction instead of a rectangular channel cross section as a raw material powder channel (see, for example, Non-Patent Document 2). ). In the powder classifying device of Non-Patent Document 2, a clean air channel having an annular channel cross section is disposed adjacent to the inner peripheral side and the outer peripheral side of the raw material powder channel having an annular channel cross section, A configuration is adopted in which the flow of the raw material powder is surrounded by clean air in the portion where the raw material powder is classified after the powder flow channel and the two clean air flow channels are merged. In addition, a uniform raw material air flow is formed along the axial direction in the raw material powder flow path, and a uniform clean air flow is formed along the axial direction in each clean air flow path. The arrangement of the respective flow paths is adjusted.

  In such a powder classification apparatus of Non-Patent Document 2, in addition to being able to suppress direct contact of the flow of the raw material powder with the flow path wall surface in the classification portion as in the apparatus of Non-Patent Document 1, a rectangular shape The existing channel end (short side end) can be eliminated in the configuration of the channel cross section, and the classification accuracy can be improved.

"Improvement of the Classification Performance of a Rectangular Jet Virtual Impactor", Kuniaki Gotoh and Hiroaki Masuda, Aerosol Science and Technology 32: 221-232 (2000), 2000 American Association for Aerosol Research "Development of annular-type virtual impactor", Kuniaki Gotoh and Hiroaki Masuda, Powder Technology 118 (2001) 68-78

  In recent years, the target of raw material powder to be classified has been diversified, and fine powder and coarse powder (or high-density powder and low-density powder) are classified with high classification accuracy from the raw material powder. There is an increasing demand to selectively and reliably take out powder having a particle size (or density) in the range. Further, depending on the characteristics and particle size of the raw material powder, the aggregating action may be increased.

  However, in such a classification system equipped with a conventional powder classification device, a disperser equipped with an ejector is disposed at a position relatively close to a raw material powder input device (for example, a quantitative feeder) and dispersed by the ejector. A configuration is adopted in which the raw material powder in a state in which the treatment is performed is supplied to the powder classifier through the inside of the pipe. For this reason, in the conventional classification system, the raw material powder that has been dispersed by the ejector of the disperser may agglomerate again in the supply pipe leading to the powder classifier. In such a case, it is difficult to improve the classification accuracy, and there is a problem that reliable dispersion treatment and classification treatment cannot be performed on the raw material powder having a relatively high agglomeration property.

  Accordingly, an object of the present invention is to solve the above-described problem, and the raw material powder conveyed in a mixed state with a gas is divided into a plurality of types of powders according to the size or density (or specific gravity) of the powder. An object of the present invention is to provide a powder classifying apparatus capable of improving the classification accuracy by performing a reliable dispersion process on the raw material powder in the powder classification process.

  In order to achieve the above object, the present invention is configured as follows.

  According to the first aspect of the present invention, the raw material powder in a state of being mixed with the gas supplied into the channel having a channel cross section having a constant width in the longitudinal direction is mixed with the first powder using inertial force. In the powder classifying apparatus for classifying the powder into the second powder, a dispersion part that crushes or disperses the raw material powder, a state that is disposed adjacent to the dispersion part, and is crushed or dispersed in the dispersion part A classification part for classifying the raw material powder into a first powder and a second powder, and the dispersion part is a flow in which a constant width of the cross section of the flow path is continuously reduced toward the downstream side and then expanded. Provided is a powder classification device which is a throttle portion of a road.

  According to the second aspect of the present invention, the flow path has an annular flow path cross section whose longitudinal direction is the circumferential direction, and in the dispersion portion, either the inner peripheral side wall surface or the outer peripheral side wall surface of the flow path. The powder classifying apparatus according to the first aspect is provided in which a flow path portion having a constant width reduced and enlarged is formed by bringing the first portion closer to the other.

  According to the third aspect of the present invention, there is provided the powder classification apparatus according to the second aspect, further comprising a swirl flow forming means for forming a swirl flow with respect to the raw material powder flowing in the annular flow path. .

  According to the fourth aspect of the present invention, as the swirl flow forming means, an introduction port for introducing the raw material powder in the tangential direction of the annular channel cross section with respect to the channel is provided. A powder classifier is provided.

  According to the fifth aspect of the present invention, as the swirl flow forming means, the protrusion or recess extending in the direction inclined with respect to the flow path direction is formed on the flow path wall surface in the throttle portion of the flow path of the dispersion section. The powder classification apparatus according to the third aspect is provided.

  According to the sixth aspect of the present invention, the first aspect to the fifth aspect are provided with a flow path portion in which the width of the flow path is kept constant along the flow path direction between the dispersion portion and the classification portion. A powder classification apparatus according to any one of the above is provided.

  According to the seventh aspect of the present invention, in the powder classification apparatus for classifying the raw material powder supplied in a state mixed with gas into the first powder and the second powder using inertial force, The raw material powder flow channel having an annular flow channel cross section and the raw material powder flow channel are arranged on the inner peripheral side and the outer peripheral side of the raw material powder flow channel in a separated state, and have an annular flow channel cross section. The raw material powder flow channel and the first and second clean air in a state where the entire outer periphery of the raw material powder flow channel is surrounded by the first and second clean air flow channels and the first and second clean air flow channels. A first flow path having an annular flow path cross section, a first flow path having a ring-shaped flow path cross section, and being arranged in a flow path direction substantially the same as the merge flow path; Communicating with the merging channel through an opening formed in the inner peripheral side wall surface of the merging channel at the communicating part of the merging channel and the first powder channel Provided with a second powder channel and a dispersion part provided in the middle of the raw material powder channel for crushing or dispersing the raw material powder. A swirling flow is formed along the circumferential direction of the annular channel cross section, and the dispersing unit is configured to bring one of the inner peripheral side wall surface and the outer peripheral side wall surface of the raw material powder channel closer to the other, thereby causing the flow. Provided is a powder classifier which is a throttle portion of a channel whose channel width is continuously reduced toward the downstream side and then expanded.

  According to the present invention, in the flow path of the powder classifier, the narrowed portion of the flow path, where the constant width of the cross section of the flow path is continuously reduced toward the downstream side and then expanded, is crushed or dispersed in the raw material powder The dispersion part is provided adjacent to the upstream side of the classification part. As a result, the raw material powder can be surely dispersed by passing the raw material powder through the narrowed portion of the flow path, and classification processing is performed in the classification unit before aggregation occurs in the dispersed raw material powder. By performing the above, high classification accuracy can be obtained.

The flowchart of the powder classification system concerning one embodiment of the present invention. External appearance front view of powder classification device of embodiment External side view of powder classification device of embodiment Exploded view of powder classification device of embodiment Schematic diagram of each flow in powder classifier (longitudinal section) Schematic diagram of each flow in the powder classifier (cross section) Schematic diagram (perspective view) of each flow in the powder classifier Schematic diagram of each flow in the vicinity of the classification unit in the apparatus of FIG. 5A Partial enlarged sectional view of the flow path of the dispersion section Partial enlarged sectional view of the flow path of the dispersion part (Modification 1) Partial enlarged sectional view of the flow path of the dispersion part (Modification 2) Top view of fine powder suction part Side view of fine powder suction part Top view of fine powder suction part according to modification Top view of coarse powder discharge flange Coarse powder discharge flange side view Partial sectional view of the through hole of the coarse powder discharge flange of FIG. 11A Cross section of the flow path at the branch

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

  A main configuration of a powder classification system including a powder classification apparatus according to an embodiment of the present invention will be described with reference to the flowchart shown in FIG.

  As shown in FIG. 1, a powder classification system 1 includes a quantitative feeder 2, a disperser 3, a powder classification device 4, a fine powder collecting bag filter 5, a coarse powder collecting bag filter 6, and a vacuum. A pump 7 and a clean air supply unit 8 are provided.

  In the powder classification system 1 according to the present embodiment, the raw material powder having a particle size distribution of 0.1 μm to several tens of μm, for example, is conveyed in a mixed state (that is, a solid-gas mixed state). Then, fine powder (second powder: for example, particle diameter of about 0.1 μm to 1 μm) and coarse powder (first powder: for example, particle diameter exceeding 1 μm) are classified and collected by the powder classifier 4. System. Moreover, as gas mixed with raw material powder, ion gas, inert gas, etc. can be used other than air.

  Such raw material powders are used in various technical fields such as fine ceramics, metal materials, polymer materials, batteries / electronic materials, composite materials, pharmaceutical materials, food materials, etc., such as electronics, energy, medicine, and food. It is intended for powders containing inorganic and organic fines. The process of selectively taking out powder having specific specifications (size, density, etc.) from the raw material powder is the powder classification process of the present invention. Further, the process of removing foreign substances other than the powder having a specific specification contained in the raw material powder from the raw material powder is also included in the powder classification process of the present invention.

  The quantitative feeder 2 is a device that quantitatively supplies the raw material powder into the powder classification system 1. In the present embodiment, for example, a micro feeder is used.

  The disperser 3 includes an ejector, and pulverizes and disperses the raw material powder supplied by the quantitative feeder 2 through the ejector. The disperser 3 may be an apparatus having a function of crushing and dispersing the raw material powder as described above, and a configuration other than the ejector may be employed. Moreover, you may comprise with a some disperser and may arrange | position just before the powder classification apparatus 4 as needed.

  The powder classifier 4 is an apparatus that selectively classifies the raw material powder dispersed in the disperser 3 and conveyed in a mixed state with gas into fine powder and coarse powder using inertial force. is there. The powder classifying device 4 includes a dispersing unit 9 and a classifying unit 10. After the dispersion processing is performed again on the raw material powder supplied into the device by the dispersing unit 9, the classifying unit 10 is provided. Classification is performed at In addition, a clean air supply unit 8 is connected to the powder classifier 4 so that clean air is supplied into the apparatus. Since the classification process is performed in the classification unit 10 in a state where the raw material powder is surrounded by the flow of clean air supplied from the clean air supply unit 8, the raw material powder adheres to the inner wall surface of the classification unit 10. Is suppressed, and high classification accuracy can be obtained. The detailed configuration of the powder classifier 4 will be described later.

  The fine powder collecting bag filter 5 collects fine powder by filtering the powder airflow containing the fine powder classified by the powder classifying device 4. Similarly, the coarse powder collecting bag filter 6 collects the coarse powder by filtering the powder airflow containing the coarse powder classified by the powder classifier 4.

  As shown in FIG. 1, in the powder classification system 1, each of the above-described device configurations is connected by a pipe line (pipe for conveying raw material powder). The vacuum pump 7 is connected to the downstream end of the entire pipe line of the powder classification system 1. By sucking the inside of the pipe line, the inside of the pipe line is maintained at a negative pressure, and is caused by the air flow of the raw material powder. Transport is performed.

  Opening control valves 5a and 6a, flow meters 5b and 6b, and pressure gauges 5c and 6c are provided on the outlet pipes of the fine powder collecting bag filter 5 and the coarse powder collecting bag filter 6, respectively. . Further, the pipe of the clean air supply unit 8 is branched into two pipes as will be described later, and the opening control valves 8a and 8d, the flow meters 8b and 8e, and the pressure gauge 8c are also provided on the respective pipes. , 8f are provided. The balance of each flow of clean air, fine powder, and coarse powder can be controlled by adjusting each opening degree control valve so that each flow meter and pressure gauge show appropriate values.

  Next, the configuration of the powder classifier 4 will be described with reference to the drawings. An external view (front view (partial cross-sectional view)) of the powder classification device 4 is shown in FIG. 2A, an external view (side view (partial cross-sectional view)) is shown in FIG. 2B, and an exploded view is shown in FIG. Note that the exploded view of FIG. 3 shows only main constituent members among the constituent members shown in the external view of the powder classifying device 4 of FIGS. 2A and 2B, for example, configurations of bolts, nuts, gaskets, and the like. The connection parts of the members and detailed parts are not shown.

  As shown in FIGS. 2A, 2B and 3, the powder classifier 4 includes a fine powder discharge pipe 11, a first clean air introduction part 12, a swivel pipe fixing flange 13, a raw material powder introduction part 14, The revolving pipe 15, the second clean air introduction part 16, the fine powder discharge pipe fixing part 17, the fine powder suction part 18, the coarse powder discharge flange 19, and the coarse powder discharge part 20 are provided.

  The first clean air introduction part 12, the swivel pipe 15, the raw material powder introduction part 14, and the second clean air introduction part 16 each have a substantially cylindrical shape. In the powder classifying device 4, the raw material powder introducing portion 14 is disposed inside the second clean air introducing portion 16, the swirling tube 15 is disposed inside the raw material powder introducing portion 14, and the fine powder is disposed inside the swirling tube 15. The powder discharge pipe 11 is disposed, and an annular channel is formed between the inner peripheral side wall surface and the outer peripheral side wall surface. The first clean air introduction part 12 is connected to the upper part of the swirl pipe 15 and communicates with the inside of the swirl pipe 15.

  The raw material powder introduction part 14 is an introduction part of the raw material powder conveyed via the pipe line from the quantitative feeder 2 and the disperser 3, and has a substantially cylindrical main body part 14a and a main body part 14a. And a raw material powder inlet (introducing pipe) 14b connected in the circumferential (tangential) direction. Further, the substantially cylindrical swirling tube 15 is arranged inside the main body portion 14a of the raw material powder introducing portion 14, so that the space between the outer peripheral side wall surface of the swirling tube 15 and the inner peripheral wall surface of the main body portion 14a is increased. A raw material powder channel having an annular channel cross section is formed. In the raw material powder introduction section 14, the raw material powder introduced from the inlet 14b forms a swirl flow in the raw material powder flow path and is conveyed downward in the figure.

  The first clean air introduction portion 12 is a clean air introduction portion communicated with one pipe line from the clean air supply portion 8, and is substantially circular with respect to the main body portion 12a and the main body portion 12a. And a first clean air inlet 12b connected in the circumferential direction. Further, the fine powder discharge pipe 11 is arranged inside the main body 12a of the first clean air introduction part 12, so that the space between the outer peripheral side wall of the fine powder discharge pipe 11 and the inner peripheral side wall of the main body 12a. A first clean air channel having an annular channel cross-section is formed. The lower part of the main body 12a is connected to the upper part of the swirl pipe 15, and a first clean air flow path is formed between the inner peripheral side wall surface of the swirl pipe 15 and the outer peripheral side wall surface of the fine powder discharge pipe 11. It is formed continuously. In the first clean air introduction section 12, the clean air introduced from the first clean air introduction port 12b forms a swirling flow in the first clean air flow path and is conveyed downward in the figure. In addition, you may arrange | position a baffle plate (for example, net-like metal member etc.) in the middle of the 1st clean air flow path. Further, the raw material powder introducing portion 14, the swirling tube 15, and the first clean air introducing portion 12 are fixed to each other by a swirling tube fixing flange 13.

  The second clean air introduction portion 16 is a clean air introduction portion communicated with the other pipe line from the clean air supply portion 8, and has a substantially cylindrical main body portion 16a and a circumferential direction of the main body portion 16a. And a second clean air inlet 16b connected to the. Further, the lower part of the raw material powder introduction part 14 is arranged inside the main body part 16a of the second clean air introduction part 16, so that the outer peripheral side wall surface of the raw material powder introduction part 14 and the inner peripheral side of the main body part 16a. A second clean air channel having an annular channel cross section is formed between the wall surface. In the second clean air introduction section 16, the clean air introduced from the second clean air introduction port 16b forms a swirling flow in the second clean air flow path and is conveyed downward in the figure. In addition, you may arrange | position a baffle plate (for example, net-like metal member etc.) in the middle of the 2nd clean air flow path.

  The fine powder discharge pipe fixing portion 17 has a generally annular shape, and the lower part of the fine powder discharge pipe 11 is connected to and communicated with the internal opening portion. Further, the upper part of the fine powder discharge pipe fixing part 17 is disposed inside the lower part of the swirl pipe 15, and the lower inner peripheral side wall surface (inclined surface) of the swirl pipe 15 and the upper outer peripheral side of the fine powder discharge pipe fixing part 17. A part of the first clean air channel having an annular channel cross section is formed between the wall surface (inclined surface). Further, the lower part of the fine powder discharge pipe fixing part 17 is arranged inside the lower part of the main body part 16a of the second clean air introduction part 16, and the inner peripheral side wall surface of the main body part 16a of the second clean air introduction part 16 A merging channel having an annular channel cross section is formed between the lower peripheral side wall surface of the fine powder discharge pipe fixing part 17. This merging channel is a channel obtained by merging the first and second clean air channels and the raw material powder channel, and details thereof will be described later.

  The fine powder suction part 18 is connected to the lower part of the fine powder discharge pipe fixing part 17 and is arranged inside the lower part of the main body part 16 a of the second clean air introduction part 16. A fine powder flow path is formed between the upper surface of the fine powder suction part 18 and the lower surface of the fine powder discharge pipe fixing part 17, and this fine powder flow path is directed from the merging flow path toward the center of the annular flow channel cross section. Are branched and communicated with the inside of the fine powder discharge pipe 11. Moreover, it extends in the same direction as the flow path direction of the merging flow path between the outer peripheral side wall surface of the fine powder suction part 18 and the lower inner peripheral side wall surface of the main body part 16a of the second clean air introduction part 16, and A coarse powder channel having an annular channel cross section is formed.

  The lower part of the second clean air introduction part 16 is connected to the coarse powder discharge part 20 via the coarse powder discharge flange 19. The coarse powder discharge unit 20 is engaged with the lower part of the fine powder suction unit 18. The coarse powder discharge unit 20 includes a substantially cylindrical main body 20a and a coarse powder discharge port 20b connected to the main body 20a in the circumferential direction. A coarse powder channel having an annular channel cross section is formed inside the cylindrical portion of the main body portion 20a, and the outer peripheral side wall surface of the fine powder suction portion 18 and the main body portion 16a of the second clean air introduction portion 16 are formed. A coarse powder passage formed between the lower inner peripheral wall surface and the coarse powder passage is communicated with the coarse powder passage. The coarse powder outlet 20a of the coarse powder discharge unit 20 is connected to the coarse powder collection bag filter 6 through a conduit.

  The fine powder discharge pipe 11 is arranged so that a lower end opening portion thereof is connected to the fine powder discharge pipe fixing portion 17 and passes through the inside of the main body portion 12a of the swivel pipe 15 and the first clean air introduction portion 12, A fine powder flow path is formed inside thereof. The upper end opening of the fine powder discharge pipe 11 is a fine powder discharge port 11a, and the fine powder discharge port 11a is connected to the fine powder collecting bag filter 5 through a pipe line.

  Here, about each flow path, such as raw material powder and clean air, in the powder classification apparatus 4, it shows schematically in FIG. 4A and FIG. 4B. 4A is a schematic diagram of the flow path in the vertical cross section of the powder classifier 4, and FIG. 4B is a schematic diagram of the flow path in the cross section along line AA in FIG. 4A.

  As shown in FIGS. 4A and 4B, a raw material powder channel 21 having an annular channel cross section is formed on the upper side of the powder classifier 4, and the inner peripheral side of the raw material powder channel 21. A first clean air channel 22 having an annular channel cross section is disposed on the outer periphery of the raw material powder channel 21, and a second clean air channel 23 having an annular channel cross section is disposed on the outer periphery side of the raw material powder channel 21. These channels have a channel cross section having a constant width in the longitudinal direction, that is, in the circumferential direction.

  Each of the flow passages 21, 22, and 23 has a flow passage cross-sectional area that is set smaller toward the downstream side. In the communication portion between the raw material powder flow passage 21 and the merge flow passage 24, The first clean air passage 22 is joined to the second clean air passage 23 from the outer peripheral side. In this joining portion, the first and second clean air passages 22 and 23 are joined to the raw material powder passage 21 in an inclined state (for example, an inclination angle of 30 degrees). As described above, the first and second clean air flow paths 22 and 23 are joined from the inner peripheral side and the outer peripheral side of the raw material powder flow path 21. Can be in a state surrounded by the flow of clean air from the inner peripheral side and the outer peripheral side. In addition, in the middle of the raw material powder flow path 21, a throttle portion whose flow path width is continuously reduced toward the downstream side and then enlarged is provided, and this throttle portion serves as the dispersion portion 9. . Details of the dispersion unit 9 will be described later.

  The flow path cross-sectional area of the merge flow path 24 is set smaller than the total of the cross-sectional areas of the raw material powder flow path 21 and the first and second clean air flow paths 22 and 23 immediately before the merge (that is, The channel cross section is narrowed toward the downstream side). Therefore, the flow of the raw material powder is accelerated when passing through the merged flow path 24.

  The merging channel 24 includes a coarse powder channel 25 having an annular channel cross section that extends in substantially the same direction as the channel direction of the merging channel 24, and an opening 24 a that is opened on the inner peripheral side wall surface of the merging channel 24. It is branched into a fine powder flow path 26 that is further toward the center (axial center) side. This branched portion P is a classification unit 10 that classifies the raw material powder into fine powder and coarse powder.

  The coarse powder passage 25 is communicated with a pipe line outside the apparatus through the coarse powder outlet 20b. Moreover, the fine powder flow path 26 is connected to the fine powder flow path 27 in the fine powder discharge pipe 11 disposed on the axial center of the apparatus, and the fine powder flow path 27 allows the flow of fine powder upward. While being formed, it communicates with a conduit outside the apparatus through the fine powder discharge port 11a.

  Here, the flow of each flow path in the powder classifier 4 is shown in the schematic perspective view shown in FIG. 5A. Moreover, the flow of the flow-path cross section in the branch position P in FIG. 5A is shown to FIG. 5B.

  As described above, a swirl flow along the circumferential direction of the annular channel cross section is formed in the raw material powder channel 21, the first and second clean air channels 22, 23 each having an annular channel cross section. Is done. Such a swirling flow is formed by swirling flow forming means. For example, as shown in FIGS. 2A and 2B, the swirling flow is circumferentially passed through the raw material powder inlet 14b and the first and second clean air inlets 12b and 16b. A swirling flow is formed by introducing each fluid along the line. In addition, the direction of each swirl | vortex flow formed in these flow paths 21, 22, and 23 is the same direction.

  Therefore, also in the merging channel 24, a swirl flow F1 in the same direction along the circumferential direction of the annular channel cross section is formed. In the swirl flow F1 in the merging channel 24, the entire raw material powder flow is surrounded by clean air from the inner peripheral side and the outer peripheral side.

  At the branch portion P in the merging channel 24, a suction force is applied by the vacuum pump 7 through each of the coarse powder channel 25 and the fine powder channel 26. A centrifugal force (inertial force) acts on the raw material powder and a downward force (axial force (inertial force)) acts on the raw material powder by the swirl flow F1 formed in the merge channel 24. Coarse powder having a relatively large particle size or high density is sucked into the coarse powder channel 25 formed in the same channel direction as the merging channel 24 because a relatively large inertial force acts. In contrast, a fine powder having a relatively small particle size or low density has an inertial force that acts against the inertial force (advancing force (force toward the center of the circle)). Then, it is sucked into the fine powder flow path 26 toward the center side. That is, coarse powder and fine powder are classified according to the relationship between the magnitude of the inertia force (centrifugal force and downward force) generated by the swirling flow and the magnitude of the suction force.

  The coarse powder sucked into the coarse powder flow path 25 is discharged from the coarse powder discharge port 20a while forming the swirl flow F2. The fine powder sucked into the fine powder flow path 26 moves toward the center side while forming the swirl flow F3, is sucked into the fine powder flow path 27 communicated with the center side, and then forms the swirl flow F4. However, the fine powder is discharged from the fine powder outlet 11a upward through the fine powder flow path 27.

  Next, the detailed structure of the dispersion | distribution part 9 is demonstrated using FIG. FIG. 6 is a partially enlarged portion of the dispersing portion 9 in the schematic diagram of the flow path of FIG. 4A.

  As shown in FIG. 6, the dispersing portion 9 is provided in the middle of the raw material powder flow channel 21, and in the annular raw material powder flow channel 21 having a constant cross section in the circumferential direction, The restricting portion 41 of the flow path whose constant width in the cross section is continuously reduced toward the downstream side and then expanded is the dispersion portion 9. A portion of the inner peripheral side wall surface 42 of the raw material powder flow channel 21 continuously approaches the outer peripheral side wall surface 43 and then leaves, thereby forming the throttle portion 41. Further, the throttle portion 41 is formed in the same shape over the entire circumferential direction.

  Further, on the downstream side of the throttle portion 41 of the flow path, a flow path portion 44 in which the width of the flow path is kept constant along the flow path direction (vertical direction) is provided. The flow path portion 44 is communicated with a joining portion with the first and second clean air flow paths 22 and 23.

  The raw material powder introduced into the raw material powder passage 21 is subjected to a compression action and its flow velocity is increased because the passage cross-sectional area is continuously reduced on the upstream side of the throttle portion 41. To do. After passing through the minimum flow path cross section of the throttle portion 41 at an increased flow rate, the flow path cross-sectional area continuously increases toward the downstream side, so that the raw material powder (flow) is subjected to an expansion action. At the same time, in a state where the flow velocity is reduced, the liquid is discharged to the adjacent flow path portion 44 having a constant width. When the raw material powder receives such an ejector action, the raw material powder is crushed and dispersed.

  In the throttle part 41, since the inner peripheral side wall surface 42 has an inclined surface, the raw material powder is inclined with respect to the flow path direction (inclined in the cross section of FIG. 6) by passing through the throttle part 41. A flow will be formed. Such a flow of the raw material powder is stabilized in the adjacent flow path portion 44, becomes a flow in a uniform direction, and can be further guided to the adjacent classification portion 10 (branch portion P) on the downstream side. . Therefore, it is possible to suppress variation in classification accuracy in the classification unit 10.

  Further, as described above, a swirl flow is formed in the raw material powder channel 21 along the circumferential direction of the annular channel cross section. As described above, since the raw material powder passes through the throttle portion 41 of the dispersion portion 9 as a swirling flow, the length of the throttle portion 41 necessary for obtaining the desired dispersion effect is sufficiently secured. Therefore, the apparatus configuration can be made compact compared to a configuration that does not use a swirling flow.

  In the form of the throttle portion 41 shown in FIG. 6, an example in which the inclination angle of the inner peripheral side wall surface 42 on the upstream side (inclination angle with respect to the flow path direction (vertical direction)) is set larger than the inclination angle on the downstream side is an example. It is said. Considering the specifications of the raw material powder and required classification accuracy, the upstream and downstream inclination angles may be the same as shown in FIG. 7, and the upstream inclination is shown in FIG. The angle may be set smaller than the inclination angle on the downstream side. Further, in the throttle portion 41, it is only necessary that the throttle portion is formed by moving either one or both of the inner peripheral side wall surface 42 and the outer peripheral side wall surface 43 closer to the other and then moving away from each other.

  Next, a swirl flow forming means for forming a swirl flow in each flow path formed in the powder classifier 4 will be specifically described.

  First, as described above, a swirl flow can be formed by introducing each fluid along the circumferential direction through the raw material powder inlet 14b and the first and second clean air inlets 12b and 16b. . Therefore, these inlets 14b, 12b, 16b are an example of the swirl flow forming means. Similarly, the coarse powder discharge port 20b is connected to the main body portion 20a so that the coarse powder is discharged along the circumferential direction of the main body portion 20a of the coarse powder discharge portion 20, whereby the coarse powder passage 25 is connected. A swirling flow can be formed in the inside. Therefore, the coarse powder outlet 20b is also an example of the swirl flow forming means.

  Further, as shown in FIGS. 2A and 2B, a plurality of recesses 15a extending obliquely downward in the figure are formed on the outer peripheral side wall surface of the swivel tube 15 so as to be arranged at predetermined intervals in the circumferential direction. . That is, a plurality of recesses 15a are formed extending in a direction inclined with respect to the flow direction (downward in the drawing) of the raw material powder flow channel 21. The plurality of recesses 15a formed in such an inclination has an action of guiding the raw material powder passing through the raw material powder channel 21 in the turning direction. Therefore, these recesses 15a are also examples of swirl flow forming means, and the formation of swirl flow can be promoted. In particular, in the raw material powder flow channel 21, by providing such a recess 15a in the throttle portion 41 (see FIG. 2A) whose flow channel width is narrower than the upstream side, the raw material powder is formed in the direction in which the recess 15a is formed (see FIG. The effect of directing in the extending direction) can be enhanced. Instead of such a recess 15a, an inclined protrusion may be formed as the swirl flow forming means. Further, such a recess or protrusion may be formed on the inner peripheral side wall surface of the main body portion 14a of the raw material powder introducing portion 14, or may be formed on the wall surface of another flow path.

  Next, a swirl flow forming means for forming a swirl flow in the fine powder passages 26 and 27 will be described. FIG. 9A shows a top view of the fine powder suction portion 18, and FIG. 9B shows a side view (partially sectional view).

  As shown in FIG. 9A, on the upper surface of the fine powder suction part 18, a plurality of turning guide parts 31 forming a flow path along a direction inclined with respect to the radial direction are arranged on the same circumference at predetermined intervals. Is formed. The swivel guide part 31 is formed so as to protrude upward from the upper surface of the fine powder suction part 18, and as shown in FIGS. 2A and 2B, each upper end contacts the lower part of the fine powder discharge pipe fixing part 17. Are arranged. Thereby, a plurality of flow paths inclined along the turning direction are formed between the adjacent turning guide portions 31, and the fine powder flow paths 26 are connected to the fine powder flow paths via the respective flow paths. 27 is communicated.

  As described above, a plurality of swirl guide portions 31 for guiding the air flow in the swirl direction are formed at the communicating portion of the fine powder flow channel 26 and the fine powder flow channel 27, so that the fine powder sucked into the fine powder flow channel 27 is formed. A swirl flow can be formed on the powder. Therefore, it can suppress that fine powder adheres to the inner peripheral side wall surface of the fine powder discharge pipe 11. Further, the swirl flow formed by the swirl guide portion 31 in this way is formed in the same direction as the swirl flow F1 in the merging flow path 24, and fine powder is smoothly fed from the fine powder flow path 26 into the fine powder flow path 27. Can lead.

  Further, as in the fine powder suction unit 18 (top view) according to the modification shown in FIG. 10, the direction of the swirl flow formed by the swirl guide unit 31 may be opposite to the swirl flow F <b> 1 of the merge channel 24. good. In such a case, the relative speed between the swirl flow F3 in the fine powder flow channel 26 and the swirl flow F4 in the fine powder flow channel 27 can be increased, and coarse powder is generated in the fine powder flow channel 27. The possibility of mixing can be reduced, and the classification accuracy can be further increased.

  Next, the swirl flow forming means for forming the swirl flow F2 in the coarse powder channel 25 will be described. 11A shows a top view of the coarse powder discharge flange 19, FIG. 11B shows a side view (partial cross-sectional view), and FIG. 11C shows a partial cross-sectional view taken along line BB of FIG. 11A.

  The coarse powder discharge flange 19 is formed with a plurality of through holes 32 arranged on the same circumference. Each through-hole 32 connects a flow path portion communicating with the merging flow path 24 and a flow path portion communicating with the coarse powder discharge port 20 b in the coarse powder flow channel 25. Further, as shown in FIG. 8C, each through hole 32 is formed to be inclined in the same direction as the swirl flow F <b> 1 of the merge channel 24. Thus, the coarse powder swirl flow F2 can be maintained by passing the through-hole 32 in the coarse powder flow path 25 while maintaining the swirl flow F1 in the merge flow path 24. Thus, also in the coarse powder flow path 25, the flow of airflow in the branch portion P is stabilized by positively forming the swirl flow F2 in the same direction as the swirl flow F1 of the merge flow path 24 (that is, the airflow Disturbance), and stable classification can be performed. Moreover, coarse powder can be stably discharged | emitted through the coarse powder discharge port 20b using such a swirl | vortex flow F2.

  Next, the flow path shape in the branch part P (classification part 10) is demonstrated using the flow-path sectional drawing of FIG.

  As shown in FIG. 12, a curved surface portion (R portion) 24 b is formed on the upper end side of the opening 24 a where the fine powder flow channel 26 communicates with the merge flow channel 24 in the branch portion P. By forming the curved surface portion 24b as described above, it is possible to suppress the turbulence of the air current in the vicinity of the curved surface portion 24b.

  Further, between the outer peripheral side wall surface of the confluence channel 24 and the outer peripheral side wall surface of the coarse powder channel 25 arranged in the same flow channel direction, a step portion 25a is formed in which the downstream portion protrudes toward the center side. ing. The step portion 25 a is formed in a portion facing the lower end side of the opening communicating with the fine powder flow path 26. By forming the step portion 25a in this way, the airflow can be guided along the outer peripheral side wall surface of the merging channel 24 and the outer peripheral side wall surface of the coarse powder channel 25, and the airflow is Separation and disturbance can be suppressed.

  As described above, the curved portion 24b and the step portion 25a are formed in the branch portion P, so that the turbulence of the airflow is suppressed and the classification accuracy can be improved.

  According to the powder classifying device 4 of the present embodiment, in the middle of the raw material powder flow channel 21, the fixed portion of the flow channel cross section is continuously reduced toward the downstream side, and then the narrowed portion of the flow channel is expanded. 41 is provided as a dispersing portion 9 for crushing or dispersing the raw material powder. Further, the dispersing unit 9 is disposed adjacent to the upstream side of the classifying unit 10. Accordingly, the raw material powder can be reliably dispersed by passing the raw material powder through the narrowed portion 41 of the flow path, and the classification unit 10 can be formed before re-aggregation occurs in the raw material powder subjected to the dispersion treatment. High classification accuracy can be obtained by performing the classification process at.

  Further, in the raw material powder channel 21 having a channel cross section having a constant width in the circumferential direction, the throttle portion 41 is formed such that a part of the inner peripheral side wall surface approaches the outer peripheral side wall surface and then moves away. Thus, the throttle portion 41 can be spatially continuously formed in the circumferential direction in the annular flow path. Therefore, a stable dispersion treatment can be performed on the raw material powder that passes therethrough. Since the narrowed portion 41 is spatially continuous in the circumferential direction, adhesion and deposition of the raw material powder can be suppressed. In addition, since the swirl portion 41 can be passed while maintaining the swirling flow flowing in the raw material powder flow channel 21, it is possible to effectively disperse the flow path configuration employing the swirling flow. .

  Further, on the downstream side of the throttle portion 41, a flow path portion 44 is provided in which the width of the flow path is kept constant along the flow path direction. As a result, the raw material powder is supplied to the classifying unit 10 in a state where the turbulence of the air flow generated by passing through the throttle portion 41 is stabilized in the flow path portion 44 and is made to flow in a substantially uniform direction. be able to. Therefore, variation in classification accuracy in the classification unit 10 can be reduced, and high classification accuracy can be obtained.

  Further, the raw material powder channel 21 having the annular channel cross section, the first and second clean air channels 22, 23, and the merge channel 24 are configured such that swirl flows in the same direction are formed. . By using the swirl flow in this way, it is possible to eliminate minute structural non-uniformities of the respective flow paths in the circumferential direction. That is, the minute difference in the channel width in the circumferential direction in each channel can be substantially uniformed by adopting the swirl flow. Therefore, it is possible to suppress airflow and pressure balance disturbance that may occur due to minute differences in flow path width, and improve classification accuracy.

  In addition, by forming a swirl flow in the merging flow path 24, a centrifugal force and a downward force can be used as the inertial force at the branch portion P, and higher classification accuracy can be obtained.

  Furthermore, by setting the flow path cross-sectional area of the merging flow path 24 to be smaller than the total flow path cross-sectional area before merging, the speed of the swirling flow in the merging flow path 24 is changed to the raw material powder flow path 21. The speed of the swirl flow can be increased. Therefore, a high inertia force can be obtained at the branch portion P, and stable classification can be performed. In addition, by adjusting the cross-sectional area of the flow path, it is possible to classify the raw material powder having a desired specification (size and density) with high accuracy.

  Further, in the flow path downstream of the branch portion P, that is, in the fine powder flow channel 26 and the coarse powder flow channel 25, the swirling flow in the same direction as the merging flow channel 24 is maintained. It is possible to suppress the turbulence of the airflow and perform stable classification.

  In addition, since the coarse powder flow path 25 is formed in substantially the same flow path direction as the merging flow path 24, it becomes possible to positively use a downward force as an inertial force in addition to the centrifugal force. Classification accuracy can be obtained.

  Further, in the branch portion P, an opening 24a communicating with the fine powder flow path 26 is formed on the inner peripheral side wall surface, and the outer peripheral side wall surface is disposed on the portion facing the opening 24a, so that The airflow from the flow path 24 toward the coarse powder flow path 25 can be stabilized, and stable classification can be performed.

  Further, the raw material powder flow channel 21 and the first and second clean air flow channels 22, 23 arranged so as to surround the raw material powder flow channel 21 are merged in the merge flow channel 24. Thereby, a flow of clean air is formed on the inner peripheral side wall surface side and the outer peripheral side wall surface side in the merging channel 24, and a raw material powder flow is formed on the inner side. Therefore, the flow of the raw material powder can be arranged in a region where the airflow is stable, and the classification accuracy can be improved. Moreover, it can suppress that raw material powder adheres to a wall surface by forming the flow of clean air on the wall surface side, and enveloping the flow of raw material powder.

  In addition to the various configurations described above, various means can be employed as the swirl flow forming means. A swirling flow may be formed by blowing an air flow from the outside toward the flow path in the direction of forming the swirling flow. For example, a desired swirl flow can be formed by blowing an air flow in the swirl direction from the outer peripheral side wall surface of the merge flow channel 24 into the merge flow channel 24. Further, a swirling flow may be formed by blowing an air flow from the outer peripheral side wall surface or the inner peripheral side wall surface of the raw material powder flow channel 21. However, in the vicinity of the branch position P in the merging flow path 24, it is preferable that there is little turbulence in the air flow, and thus the formation of the swirling flow by the air flow blowing can be performed in a flow path other than the vicinity of the branch position P. preferable.

  Further, in the above description, the powder classification device 4 has been described as an example of the configuration in which the raw material powder passage having an annular passage cross section having a constant width in the circumferential direction is provided. It is not limited only to a simple configuration. For example, the configuration of the throttle portion 41 (dispersing portion 9) may be applied to a configuration including a raw material powder channel having a rectangular channel cross section having a certain width in the longitudinal direction.

  In the above description, the raw material powder flow channel 21 is described as an example of the flow channel configuration surrounded by the first and second clean air flow channels 22 and 23 from the inner and outer peripheral sides. The present invention can also be applied to a channel configuration that does not use a channel.

  In the above-described embodiment, the powder classification device 4 separates the raw material powder according to the powder size and classifies it into coarse powder (first powder) and fine powder (second powder). However, the powder classification apparatus of the present invention is not limited to such a case. In the powder classifying apparatus of the present invention, the raw material powder is separated according to the powder density, and the raw material powder is divided into a high density powder (first powder) and a low density powder (second powder). It may be a case where classification is performed.

  It is to be noted that, by appropriately combining any of the above-described various embodiments, the effects possessed by them can be produced.

DESCRIPTION OF SYMBOLS 1 Powder classification system 2 Fixed feeder 3 Dispersing machine 4 Powder classification apparatus 5 Bag filter for fine powder collection 6 Bag filter for coarse powder collection 7 Vacuum pump 8 Clean air supply part 9 Dispersion part 10 Classification part 11 Fine powder discharge pipe 12 First clean air introduction part 13 Swivel pipe fixing flange 14 Raw material powder introduction part 15 Swivel pipe 16 Second clean air introduction part 17 Fine powder discharge pipe fixing part 18 Fine powder suction part 19 Coarse powder discharge flange 21 Raw material powder flow path 22 1st clean air flow path 23 2nd clean air flow path 24 Merge flow path 25 Coarse powder flow path 26 Fine powder flow path 27 Fine powder flow path 41 Restriction part

Claims (7)

Powder that classifies raw material powder in a state of being mixed with a gas supplied in a channel having a channel cross section having a constant width in the longitudinal direction into a first powder and a second powder using inertial force In the classification device,
A dispersion part for crushing or dispersing the raw material powder;
A classifying unit that is arranged adjacent to the dispersing unit and classifies the raw material powder in a state of being crushed or dispersed in the dispersing unit into a first powder and a second powder;
The dispersion unit is a powder classifier, which is a narrowed portion of the flow path in which a constant width of the flow path cross section is continuously reduced toward the downstream side and then expanded. The flow path has an annular flow path cross section with the circumferential direction as the longitudinal direction,
2. The flow path portion in which a constant width is reduced and expanded by forming one of the inner peripheral wall surface and the outer peripheral wall surface of the flow path closer to the other in the dispersion portion. Powder classifier.   The powder classification device according to claim 2, further comprising a swirl flow forming means for forming a swirl flow with respect to the raw material powder flowing in the annular flow path.   The powder classification device according to claim 3, wherein an introduction port for introducing the raw material powder in a tangential direction of the cross-section of the annular flow channel with respect to the flow channel is provided as the swirl flow forming means.   The powder according to claim 3, wherein as the swirl flow forming means, a protrusion or a recess extending in a direction inclined with respect to the flow path direction is formed on the flow path wall surface in the throttle portion of the flow path of the dispersion section. Body classification device.   The powder classification apparatus according to any one of claims 1 to 5, further comprising a flow path portion in which the width of the flow path is kept constant along the flow path direction between the dispersion section and the classification section. In a powder classification apparatus for classifying raw material powder supplied in a mixed state with gas into a first powder and a second powder using inertial force,
A raw material powder channel having an annular channel cross section;
A first and a second clean air channel having an annular channel cross section, which are respectively disposed on the inner peripheral side and the outer peripheral side of the source powder channel in a state separated from the source powder channel;
A merged flow channel in which the raw material powder flow channel and the first and second clean air flow channels are joined in a state where the entire outer periphery of the raw material powder flow channel is surrounded by the first and second clean air flow channels; ,
A first powder channel having an annular channel cross section, communicated with the merge channel and disposed in substantially the same channel direction as the merge channel;
A second powder flow channel communicated with the merged flow channel through an opening opened on the inner peripheral side wall surface of the merged flow channel at a communication portion between the merged flow channel and the first powder flow channel;
Provided in the middle of the raw material powder flow path, with a dispersion unit for crushing or dispersing the raw material powder,
In the raw material powder channel and the merging channel, a swirl flow along the circumferential direction of the annular channel cross section is formed,
The dispersing portion is a flow in which the flow path width is continuously reduced toward the downstream side and then expanded by bringing one of the inner peripheral wall surface and the outer peripheral wall surface of the raw material powder flow channel closer to the other. A powder classifier that is the throttle part of the road.

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