Airflow classifier

Abstract

The present application provides a gas flow classifier capable of maintaining classification accuracy for a long period of time and having a smaller classification point. The gas flow classifier includes: a housing having a ceiling wall and a ring wall continuously provided with an outer edge of the ceiling wall; a classification plate configured to have a surface opposite to the ceiling wall of the housing; a classification chamber formed between the ceiling wall of the housing and the surface of the classification plate; a gas supply unit configured to supply a gas into the classification chamber to generate a rotational flow; a raw material supply unit configured to supply a raw material powder into the classification chamber to generate the rotational flow; a fine powder discharge port provided at a central portion of one of the ceiling wall of the housing and the surface of the classification plate forming the classification chamber; a coarse powder discharge port provided at either side of the ceiling wall and the surface of the classification plate opposite to the ceiling wall and forming an opening along an outer periphery of the classification chamber; and a groove portion provided on at least one of the ceiling wall and the surface of the classification plate.

Description

Technical Field

[0001] This invention relates to an airflow classifier that utilizes the balance between centrifugal force and resistance brought to the powder by the swirling flow of gas to classify raw material powder with a particle size distribution into fine powder and coarse powder at a desired particle size (classification point). In particular, it relates to an airflow classifier that can maintain classification accuracy and achieve smaller classification points. Background Technology

[0002] Currently, microparticles such as oxide microparticles, nitride microparticles, and carbide microparticles are used in various fields, including: electrical insulation materials such as semiconductor substrates, printed circuit boards, and various electrical insulation parts; high-hardness and high-precision mechanical working materials such as cutting tools, molds, and bearings; functional materials such as humidity sensors; sintered bodies used to manufacture precision sintered materials; sputtered parts used to manufacture materials requiring high temperature resistance and wear resistance, such as engine valves; and electrode, electrolyte materials, and various catalysts for fuel cells. By using these microparticles, the bonding strength, density, and even functionality between dissimilar ceramics or dissimilar metals can be improved during the manufacture of sintered bodies and sputtered parts.

[0003] The aforementioned microparticles can be manufactured through chemical methods, such as using high temperatures to induce chemical reactions in various gases, or through physical methods, such as using electron beams or laser beams to decompose and evaporate substances to generate microparticles. Microparticles manufactured using these methods have a particle size distribution, with coarse and fine powders mixed together. When used for the aforementioned applications, a low proportion of coarse powder in the microparticles yields better properties; therefore, a low proportion of coarse powder is preferred. Furthermore, for metallic microparticles, a low proportion of coarse powder also yields better properties; therefore, a low proportion of coarse powder is also preferred.

[0004] Therefore, airflow classifiers and powder classification devices, for example, use swirling flow to make powders swirl and centrifugally separate them into coarse and fine powders.

[0005] For example, Patent Document 1 describes a powder classification device that uses airflow to transport and supply powder with a particle size distribution. The powder classification device of Patent Document 1 has: a disc-shaped hollowed-out cavity (disc-shaped cavity section) that serves as a space for classifying the supplied powder with a particle size distribution; a powder supply port for supplying the powder with a particle size distribution to the disc-shaped cavity section; a plurality of guide vanes arranged to extend inward from the outer periphery of the disc-shaped cavity section at a predetermined angle; an exhaust section including an airflow of fine powder discharged from the disc-shaped cavity section and a recovery section for coarse powder discharged from the disc-shaped cavity section; and a plurality of air nozzles arranged below the plurality of guide vanes and along the tangential direction of the outer peripheral wall of the disc-shaped cavity section, which blow compressed air into the coarse powder recovery section side inside the disc-shaped cavity section and send the fine powder located on the coarse powder recovery section side back to the disc-shaped cavity section.

[0006] In addition, Patent Document 2 describes a grading device that guides powder supplied from a supply port located at the top of the device body downward while rotating within the device body. A suction tube composed of multiple tubes with a suction port at the top is provided at the center of the device body. Smaller particles in the powder that is guided downward while rotating are attracted from the suction port through the suction tube.

[0007] In Patent Document 2, powders with different particle sizes are collected one by one by an attraction tube composed of multiple tubes.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent No. 4785802

[0011] Patent Document 2: Japanese Patent Application Publication No. 2000-107698 Summary of the Invention

[0012] The technical problem that the invention aims to solve

[0013] While the powder classification device in Patent Document 1 can classify raw material powder with particle size distribution into fine powder and coarse powder at the desired particle size (classification point), the particle size of the required fine powder is getting smaller and smaller recently. Therefore, the industry expects to further miniaturize the classification point of the powder classification device.

[0014] Furthermore, Patent Document 2 describes a process of classifying a raw material powder using a single classification operation, and using the aforementioned suction tube composed of multiple tubes to recover powders of different particle sizes from each tube constituting the multiple tubes.

[0015] Therefore, although Patent Document 2 can utilize the various tubes constituting multiple tubes to recover powder separately and can reduce the inconsistency in the particle size of the recovered powder, the classification point depends on the airflow balance of each suction tube, and thus cannot achieve miniaturization of the classification point.

[0016] Furthermore, when classifying powders, the ideal outcome is to achieve stable classification over a long period and maintain classification accuracy over an extended period.

[0017] The purpose of this invention is to solve the problems caused by the aforementioned known technologies, and to provide an airflow classifier that can maintain classification accuracy over a long period of time and has smaller classification points.

[0018] Means for solving technical problems

[0019] To achieve the above objectives, one aspect of the present invention provides an airflow classifier comprising: a housing having a top wall and an annular wall continuously disposed along the outer edge of the top wall; a classifying plate disposed with its surface facing the top wall of the housing; a classifying chamber formed between the surface of the top wall of the housing and the surface of the classifying plate; a gas supply unit supplying gas to the classifying chamber to generate a swirling flow; a raw material supply unit supplying raw material powder to the swirling flow generated in the classifying chamber; a fine powder outlet disposed at the center of one of the surfaces of the top wall of the housing constituting the classifying chamber and the classifying plate; a coarse powder outlet disposed on either side of the surface of the top wall and the surface of the classifying plate facing the top wall, and forming an opening along the outer periphery of the classifying chamber; and a groove provided on at least one of the surfaces of the top wall and the classifying plate.

[0020] Preferably, it further comprises at least one of a first cylindrical portion and a second cylindrical portion, wherein the first cylindrical portion is disposed at the fine powder outlet; and the second cylindrical portion is disposed on the surface of the grading plate of the grading chamber and faces the first cylindrical portion with a predetermined gap.

[0021] Preferably, the diameter of the first cylindrical portion is different from the diameter of the second cylindrical portion.

[0022] Preferably, at least one of the top wall of the housing and the surface of the grading plate is formed with an inclined surface, and the inclined surface is provided with a groove.

[0023] At least one of the periphery of the first cylindrical portion of the top wall of the housing and the periphery of the second cylindrical portion of the surface of the grading plate is formed with an inclined surface, and a groove is provided on the inclined surface.

[0024] Preferably, the fine powder outlet is circular, and the groove is configured to form concentric circles relative to the fine powder outlet.

[0025] Preferably, the groove is provided on the surface of the ceiling wall and the grading plate.

[0026] Preferably, the fine powder outlet is circular, the groove is configured to form a concentric circle with respect to the fine powder outlet, and the groove on the ceiling wall faces the groove on the surface of the grading plate.

[0027] Preferably, on the side of the ceiling wall and the grading plate that has a fine powder outlet, a groove is provided around the fine powder outlet in a concentric circle with the fine powder outlet. On the side that does not have a fine powder outlet, a concentric groove is provided opposite to the concentric groove provided around the fine powder outlet. Furthermore, both the concentric groove provided on the side with the fine powder outlet and the concentric groove provided on the side without the fine powder outlet are located at the same position in a direction orthogonal to the direction facing each other on the ceiling wall and the grading plate of the grading chamber housing.

[0028] Preferably, a plurality of grooves are provided around the fine powder outlet.

[0029] Preferably, the ceiling wall has a first cylindrical portion, and the surface of the grading plate has a groove portion.

[0030] Preferably, the surface of the grading plate has a second cylindrical portion, and a groove portion is provided in the ceiling wall.

[0031] Preferably, the slope is formed in such a way that it slopes from the outside of the grading chamber toward the center and the height of the grading chamber gradually increases.

[0032] Preferably, the ramp slopes in a manner that the ramp slopes from the outside of the grading chamber toward the center and the height of the grading chamber decreases.

[0033] Preferably, the raw material supply unit is connected to either the top wall of the housing constituting the classification chamber or the surface of the classification plate, and is used to supply the raw material powder to the swirling flow that occurs within the classification chamber.

[0034] Preferably, the raw material supply section has a nozzle for supplying raw material powder to the swirling flow generated in the classification chamber.

[0035] Preferably, the gas supply unit has a plurality of air nozzles, each air nozzle being arranged circumferentially along the outer edge of the classification chamber at equal intervals.

[0036] Preferably, the gas supply section has a plurality of guide vanes, each guide vane being arranged circumferentially along the outer edge of the classification chamber at equal intervals.

[0037] The effects of the invention

[0038] According to the present invention, when classifying raw material powder with particle size distribution into fine powder and coarse powder, it is possible not only to maintain the classification accuracy for a long period of time, but also to make the classification point smaller than that of the prior art. Attached Figure Description

[0039] Figure 1 A schematic cross-sectional view showing a first example of an airflow classifier according to an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram showing an example of the groove portion of a first example of an airflow classifier according to an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram showing other examples of the groove portion of the first example of the airflow classifier according to an embodiment of the present invention.

[0042] Figure 4 A schematic cross-sectional view showing a second example of an airflow classifier according to an embodiment of the present invention.

[0043] Figure 5 This is a partial cross-sectional schematic diagram showing a third example of an airflow classifier according to an embodiment of the present invention.

[0044] Figure 6 This is a partial cross-sectional schematic diagram showing a fourth example of an airflow classifier according to an embodiment of the present invention.

[0045] Figure 7 This is a partial cross-sectional schematic diagram showing a fifth example of an airflow classifier according to an embodiment of the present invention.

[0046] Figure 8 This is a partial cross-sectional schematic diagram showing a sixth example of an airflow classifier according to an embodiment of the present invention.

[0047] Figure 9 This is a partial cross-sectional schematic diagram showing the seventh example of an airflow classifier according to an embodiment of the present invention.

[0048] Figure 10 This is a partial cross-sectional schematic diagram showing the eighth example of an airflow classifier according to an embodiment of the present invention.

[0049] Figure 11 This is a partial cross-sectional schematic diagram showing the ninth example of an airflow classifier according to an embodiment of the present invention.

[0050] Figure 12 This is a partial cross-sectional schematic diagram showing a 10th example of an airflow classifier according to an embodiment of the present invention.

[0051] Figure 13This is a cross-sectional schematic diagram showing the 11th example of an airflow classifier according to an embodiment of the present invention.

[0052] Figure 14 A cross-sectional schematic diagram of the first airflow classifier used for comparison.

[0053] Figure 15 Statistical charts to display the results of the grading.

[0054] Figure 16 This is a schematic diagram showing ceramic particles after being classified by the airflow classifier of the present invention.

[0055] Figure 17 A schematic diagram showing ceramic particles classified by a first airflow classifier used for comparison.

[0056] Figure 18 This is a partial cross-sectional schematic diagram of a second airflow classifier used for comparison.

[0057] Figure 19 Statistical charts to display the results of the grading.

[0058] Figure 20 This is a schematic diagram showing ceramic particles after being classified by the airflow classifier of the present invention.

[0059] Figure 21 This is a schematic diagram showing ceramic particles classified by a second airflow classifier used for comparison.

[0060] Figure Labels

[0061] 10, 10a, 10b, 10c, 10d, 10e, 10f, 10g air classifiers; 10h, 10i, 10j air classifiers; 12 casing; 12a surface; 13 roof wall; 13b outer edge; 14 upper disc-shaped section; 14a, 16b fine powder outlet; 16 classifying plate; 16a outer end; 18 classifying chamber; 19 annular wall; 20 first cylindrical section; 22 second cylindrical section; 23 gap; 24a first field; 24b inclined section; 26a second field; 26b inclined section; 28 coarse powder... Powder recovery chamber, 30 fine powder recovery pipe, 30c end, 34 first air nozzle, 36 second air nozzle, 38 third air nozzle, 39 gap, 40 raw material supply section, 42 supply pipe, 50, 51, 52 groove section, 54 spray section, 55 spray nozzle, 56 piping, 60 fine powder recovery pipe, 62 guide vane, 64 propulsion chamber, 66 coarse powder outlet, 100 first airflow classifier, 102 second airflow classifier, H direction, Pc coarse powder, Pf fine powder, Ps raw material powder, W direction, β, θ angle. Detailed Implementation

[0062] The airflow classifier of the present invention will now be described in detail with reference to the preferred embodiment shown in the accompanying drawings.

[0063] Furthermore, the figures described below are merely illustrative examples for the purpose of explaining the present invention, and the present invention is not limited to the examples shown in the figures below.

[0064] (The first example of an air classifier)

[0065] Figure 1 A schematic cross-sectional view showing a first example of an airflow classifier according to an embodiment of the present invention; Figure 2 A schematic diagram showing an example of the groove portion of a first example of an airflow classifier according to an embodiment of the present invention; Figure 3 This is a schematic diagram showing other examples of the groove portion of the first example of the airflow classifier according to an embodiment of the present invention.

[0066] Figure 1 The airflow classifier 10 shown utilizes the balance between the centrifugal force and resistance brought to the powder by the swirling flow formed by the gas to classify raw material powder with particle size distribution into fine powder Pf and coarse powder Pc at the desired particle size (classification point).

[0067] Figure 1 The airflow classifier 10 shown, for example, has a cylindrical housing 12. The housing 12 has a top wall 13 and an annular wall 19 continuously disposed along the outer edge 13b of the top wall 13. The top wall 13 is a component constituting a circular upper disc-shaped portion 14, which is also present in the housing 12. The classifying plate 16 is configured such that its surface 16c faces the top wall 13 (i.e., the upper disc-shaped portion 14) of the housing 12 at a predetermined interval. The classifying plate 16 is approximately circular in shape. The upper disc-shaped portion 14 (top wall 13) and the classifying plate 16 are configured to face each other in the H direction.

[0068] A slightly disc-shaped classification chamber 18 is separated between the upper disc-shaped portion 14 and the classification plate 16. The outer circumference of the classification chamber 18 is enclosed by the annular wall 19 of the housing 12. Therefore, the classification chamber 18 is the space sandwiched between the opposing ceiling wall 13 (the surface 14c of the upper disc-shaped portion 14) and the surface 16c of the classification plate 16; the classification chamber 18 is constructed between the ceiling wall 13 of the housing 12 and the surface 16c of the classification plate 16. Therefore, both the upper disc-shaped portion 14 (ceiling wall 13) and the classification plate 16 are components that constitute the space of the classification chamber 18. Raw material powder with a particle size distribution is classified in the classification chamber 18 and separated into, for example, coarse powder and fine powder.

[0069] A fine powder outlet 14a is formed in the center of the upper disc-shaped portion 14. The fine powder outlet 14a is connected to the classification chamber 18. The fine powder outlet 14a is, for example, circular. The fine powder outlet 14a is used to discharge the coarse powder and fine powder from the fine powder produced by the separation of the raw material powder in the classification chamber 18 as described later.

[0070] The surface 14c of the upper disc-shaped portion 14 facing the grading chamber 18 is, for example, formed by a plane parallel to the W direction. This W direction is orthogonal to the H direction.

[0071] The surface 16c of the grading plate 16 facing the grading chamber 18 is, for example, formed by a plane parallel to the W direction. The surface 14c of the upper disc-shaped portion 14 is parallel to the surface 16c of the grading plate 16.

[0072] In the upper disc-shaped portion 14, a groove portion 50 is provided in a first area 24a around the fine powder discharge port 14a. The groove portion 50 is configured to be recessed relative to the surface 14c of the upper disc-shaped portion 14.

[0073] For example, groove 50 Figure 2 As shown, the groove portion 50 is arranged in a concentric circle around the fine powder outlet 14a along the fine powder outlet 14a. On the ceiling wall 13 (upper disc-shaped portion 14) where the fine powder outlet 14a is provided, the groove portion 50 is arranged in a concentric circle around the fine powder outlet 14a.

[0074] In the grading plate 16, a groove portion 51 is provided in a second region 26a facing the first region 24a surrounding the fine powder outlet 14a. The groove portion 51 is configured to be recessed relative to the surface 16c of the grading plate 16. In other words, in a component without an opening (e.g., the grading plate 16), a concentrically circular groove portion 51 is provided facing the concentrically circular groove portion 50 provided in the region surrounding the fine powder outlet 14a. The groove portion 51 has the same structure as the groove portion 50.

[0075] The groove portion 50 of the upper disc-shaped portion 14 and the groove portion 51 of the grading plate 16 are arranged to face each other in the H direction. For example, the concentric groove portion 50 provided in the upper disc-shaped portion 14 (one of the components) and the concentric groove portion 51 provided in the grading plate 16 (the other component) are arranged at the same position in the W direction, which is orthogonal to the H direction of the two components of the grading chamber 18, namely the upper disc-shaped portion 14 and the grading plate 16 facing each other.

[0076] Both groove portion 50 and groove portion 51 have rectangular cross-sectional shapes. However, the cross-sectional shapes of groove portion 50 and groove portion 51 are not limited to rectangular shapes; the bottom can be a flat surface, a curved surface, or a bent surface. For example, the cross-sectional shape can also be U-shaped or V-shaped.

[0077] Although groove portion 51 and groove portion 50 have the same structure, with the same width in the W direction and the same depth in the H direction, they are not limited to this. The width in the W direction and the depth in the H direction of groove portion 50 and groove portion 51 may also be different.

[0078] Furthermore, the location of the groove portion 50 is only required to be in the first area 24a around the fine powder discharge port 14a, and is not limited to being located along the outer edge of the fine powder discharge port 14a.

[0079] Although the aforementioned groove portions 50 and 51 are configured as follows: Figure 2 As shown, it forms a concentric circle with the fine powder outlet 14a, but it is not limited to this. For example, it can also be used... Figure 3 As shown, a plurality of grooves 52 are provided around the fine powder outlet 14a. The opening of the groove 52 is, for example, circular.

[0080] Furthermore, it is sufficient that at least one of the components constituting the upper disc-shaped portion 14 and the classifying plate 16 facing each other in the classifying chamber 18 is provided with a groove. In other words, it is sufficient that at least one of the first field 24a surrounding the fine powder discharge outlet 14a and the second field 26a facing the first field 24a surrounding the fine powder discharge outlet 14a adopts a structure with a groove having a recessed portion.

[0081] By incorporating grooves, the adhesion of powder to the classification chamber 18 can be suppressed during powder classification. Although powder will eventually detach if it does adhere to the chamber, suppressing adhesion reduces the probability of detachment. This allows for stable classification over a long period, thus maintaining classification accuracy over extended periods.

[0082] Furthermore, the grading point can be made smaller. In other words, it is possible to grade fine and coarse powders at smaller particle sizes. In addition, by providing the groove portion, the velocity of the powder flowing from outside the device to the fine powder discharge port 14a can be locally suppressed, thus reducing the grading point. In this way, it is possible to grade fine and coarse powders at smaller particle sizes.

[0083] As described above, although a structure with a groove portion 50 having an upper disc-shaped portion 14 and a groove portion 51 having a grading plate 16 is adopted, it is not limited to this. As long as a structure with at least one of the groove portion 50 having an upper disc-shaped portion 14 and a groove portion 51 having a grading plate 16 is adopted, it is acceptable.

[0084] The fine powder recovery pipe 30, located at the fine powder outlet 14a, extends in a direction perpendicular to the surface 12a of the housing 12. This perpendicular direction is parallel to the aforementioned H direction.

[0085] The fine powder recovery pipe 30 is a component used to discharge the gas containing the fine powder Pf after classification in the classification chamber 18 to the outside of the classification chamber 18 through the gap 23. The fine powder recovery pipe 30 is connected to an exhaust fan (not shown) at its end 30c on the opposite side of the classification chamber 18, for example, via a bag filter (not shown). The bag filter (not shown) and the exhaust fan (not shown) constitute a fine powder recovery device. Furthermore, the fine powder recovery pipe 30 constitutes a fine powder recovery section. The coarse powder and the fine powder generated from the separation of the raw material powder in the classification chamber 18 are discharged from the fine powder discharge port 14a of the upper disc-shaped section 14.

[0086] Furthermore, a gap 39 is provided between the outer end 16a of the grading plate 16 and the annular wall 19 of the housing 12. The gap 39 is located at the outer edge of the grading chamber 18. A coarse powder recovery chamber 28, for example, in the shape of a hollow frustum-shaped cone, is provided below the housing 12. The grading chamber 18 and the coarse powder recovery chamber 28 are connected through the gap 39. In addition, the outer edge of the grading chamber 18 is higher than the central part in the H direction, and the outer edge of the grading chamber 18 expands in the H direction.

[0087] The coarse powder recovery chamber 28 is used to discharge the coarse powder Pc, which has been classified in the classification chamber 18, to the outside of the classification chamber 18. The coarse powder recovery chamber 28 is equipped with a coarse powder recovery pipe (not shown) for collecting the classified coarse powder. A hopper (not shown) is located at the lower end of the coarse powder recovery pipe via, for example, a rotary valve (not shown). The coarse powder Pc, after being classified in the classification chamber 18, passes through gap 39 and through the coarse powder recovery chamber 28 and the coarse powder recovery pipe to be recovered into the hopper. The aforementioned gap 39 constitutes the coarse powder discharge port 66. The coarse powder discharge port 66 is used to discharge the coarse powder and fine powder generated during the separation of the raw material powder in the classification chamber 18.

[0088] The coarse powder recovery section is composed of coarse powder recovery chamber 28. According to... Figure 1 The structure of the coarse powder recovery section shown discharges fine powder Pf from the upper disc-shaped section 14 (one of the components) and discharges coarse powder Pc from the gap 39 (coarse powder discharge port 66) located on the outer edge of the classification chamber 18 from the classification plate 16 (the other component).

[0089] The coarse powder recovery section, such as the coarse powder recovery chamber 28, is located on either the upper disc-shaped section 14 (one of the components) or the classification plate 16 (the other component) which faces the upper disc-shaped section 14 (one of the components) across the classification chamber 18. It is situated on the outer edge of the classification chamber 18 and communicates with the interior of the classification chamber 18, serving to discharge the classified coarse powder Pc from the classification chamber 18 to the outside of the classification chamber 18. The structure of the coarse powder recovery section is not limited to... Figure 1 The structure shown.

[0090] In the annular wall 19 of the housing 12, a plurality of first air nozzles 34 are provided on the side of the fine powder recovery pipe 30 in the H direction. Furthermore, in the annular wall 19, below the first air nozzles 34 in the H direction, a second air nozzle 36 is provided. In other words, a plurality of second air nozzles 36 are provided.

[0091] Furthermore, within the cylindrical housing 12, below the second air nozzle 36 in the H direction, a third air nozzle 38 is provided. In other words, a plurality of third air nozzles 38 are provided.

[0092] Although no detailed illustration is provided, a plurality of first air nozzles 34, such as six, are provided along the outer edge of the grading chamber 18, each forming a predetermined angle with respect to the tangential direction of the outer edge of the grading chamber 18, and are arranged at equal intervals in the circumferential direction of the grading chamber 18.

[0093] The second air nozzle 36 and the third air nozzle 38 are also provided in a plurality, for example, six, along the outer edge of the classification chamber 18, similar to the first air nozzle 34. They are arranged at predetermined angles relative to the tangential direction of the outer edge of the classification chamber 18 and are evenly spaced along the circumference of the classification chamber 18. The gas supply unit includes the first air nozzle 34 and the second air nozzle 36. While the gas supply unit may be configured to include both the first air nozzle 34 and the second air nozzle 36, it may also include only the first air nozzle 34 or the second air nozzle 36.

[0094] The first air nozzle 34, the second air nozzle 36, and the third air nozzle 38 are respectively connected to a pressurized gas supply unit (not shown) and have gas injection ports. Gas at a predetermined pressure from the pressurized gas supply unit is supplied to the first air nozzle 34 and the second air nozzle 36, and pressurized gas is then ejected from the first air nozzle 34 and the second air nozzle 36, thereby forming a swirling flow within the classification chamber 18 in which all flows in the same direction. Furthermore, the gas used is appropriately selected based on the raw material powder to be classified or the desired outcome; for example, air can be used. If the raw material powder reacts with air, other non-reactive gases can be appropriately used instead.

[0095] In addition, a gas at a specified pressure is supplied from the pressurized gas supply section to the third air nozzle 38, and then pressurized gas is ejected from the third air nozzle 38, and the pressurized gas is supplied to the gap 39 between the outer end 16a of the grading plate 16 and the housing 12.

[0096] The number of the first air nozzle 34, the second air nozzle 36, and the third air nozzle 38 is not limited to the number mentioned above. There may be a single one or multiple ones. The appropriate number is determined according to the conditions of the device structure, etc.

[0097] Furthermore, the second air nozzle 36 is not limited to a nozzle; it may also be a guide vane or the like, as described later, depending on the conditions of the device structure, etc.

[0098] A supply pipe 42 is provided on the surface 12a of the housing 12, and this supply pipe 42 is spaced apart from the fine powder recovery pipe 30 in the W direction by a predetermined interval. The supply pipe 42 is located on the outer edge of the housing 12. For example, a raw material supply section 40 for supplying raw material powder Ps into the classification chamber 18 is provided at the upper part of the supply pipe 42. The supply pipe 42 is, for example, a hollow frustum-shaped cone. The supply pipe 42 is configured such that the front end of the cone with a smaller diameter faces the surface 12a of the housing 12. The connection between the supply pipe 42 and the housing 12 is made of a pipe with a fixed diameter. The supply pipe 42 is connected, for example, to an upper disc-shaped part 14, through which the raw material powder Ps is supplied into the classification chamber 18.

[0099] Next, the operation of the air classifier 10 will be explained.

[0100] First, an exhaust fan (not shown) draws air from the classification chamber 18 through the fine powder recovery pipe 30 at a specified air volume. At the same time, pressurized gas is supplied from the pressurized gas supply unit (not shown) to the first air nozzle 34 and the second air nozzle 36 respectively to create a swirling flow in the classification chamber 18.

[0101] In this state, a predetermined amount of raw material powder Ps with particle size distribution is supplied from the raw material supply section 40 to the swirling flow in the classification chamber 18 through the opening 42a of the upper disc-shaped section 14.

[0102] Since pressurized gas is ejected from the first air nozzle 34 and the second air nozzle 36 to create a swirling flow within the classification chamber 18, the raw material powder Ps supplied to the classification chamber 18 from the raw material ejection nozzle (not shown) will swirl within the classification chamber 18, undergoing centrifugal separation. As a result, the velocity of the powder moving from outside the device toward the fine powder discharge port 14a can be locally suppressed by the grooves 50 and 51 provided in the classification chamber 18, thus reducing the classification point. In this way, fine and coarse powders can be classified at smaller particle sizes. Therefore, coarse powder Pc with a larger particle size will not flow into the fine powder recovery pipe 30 through the fine powder discharge port 14a, but will remain in the classification chamber 18. On the other hand, fine powder Pf with a size below the classification point will be drawn out of the fine powder recovery pipe 30 along with the airflow through the fine powder discharge port 14a and discharged.

[0103] In this way, fine powder Pf can be separated and recovered from raw material powder Ps with a particle size distribution. Furthermore, as described above, the groove portions 50 and 51 can suppress powder adhesion into the classification chamber 18. Since classification can be performed stably over a long period, classification accuracy can be maintained for an extended period. Moreover, the particle size of the recovered fine powder Pf can be reduced.

[0104] Furthermore, the remaining portion of the raw material powder that is not discharged from the fine powder recovery pipe 30, i.e., coarse powder Pc, falls from the classification chamber 18 into the coarse powder recovery chamber 28 through the gap 39 between the classification plate 16 and the annular wall 19. Then, the remaining portion of the raw material powder, i.e., coarse powder Pc, is recovered via the coarse powder recovery pipe (not shown).

[0105] Compared to air nozzles, guide vanes can sometimes achieve higher precision in grading due to differences in airflow and other conditions. Therefore, the traditional guide vane method can also be used depending on the purpose of grading.

[0106] In the airflow classifier 10, the outer circumference of the roughly disc-shaped classification chamber 18 is sealed by an annular wall 19. Therefore, even if a large flow of pressurized gas is forcibly injected from the first air nozzle 34 and the second air nozzle 36, air will not leak outwards in the circumferential direction of the classification chamber 18, and the resulting swirling flow will not become disordered. Therefore, in particular, the inflow rate of pressurized gas from the first air nozzle 34, which is used to form a swirling flow in the coarse powder recovery chamber 28, can be increased, thereby enabling the stable classification of submicron particles.

[0107] Although submicron-sized particles tend to agglomerate easily, an air classifier 10 can efficiently classify them by spraying a large flow of pressurized gas from the first air nozzle 34 and the second air nozzle 36. Furthermore, various powders, ranging from low-density powders such as silica and carbon powder to high-density powders such as metals and alumina, can be used as the raw material for classification.

[0108] In addition, depending on the purpose of the classification, the second air nozzle 36 can also be replaced with a guide vane with a larger air volume setting range.

[0109] (Example 2 of an air classifier)

[0110] Figure 4 A schematic cross-sectional view showing a second example of an airflow classifier according to an embodiment of the present invention.

[0111] exist Figure 4 In the air classifier 10a shown, with Figure 1 The components of the airflow classifier 10 shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0112] Figure 4 The air classifier 10a shown is Figure 1 Compared to the airflow classifier 10 shown, the only difference lies in the fact that it has a cylindrical first cylindrical section 20 and a cylindrical second cylindrical section 22; all other structures are the same. Figure 1 The airflow classifier 10 shown is the same.

[0113] The upper disc-shaped portion 14 of the airflow classifier 10a has a first cylindrical portion 20 protruding into the classification chamber 18 along the edge of the fine powder outlet 14a. The first cylindrical portion 20 is constructed, for example, as a cylindrical member with the same inner diameter as the fine powder outlet 14a. The first cylindrical portion 20 is connected to the fine powder outlet 14a. On another component, namely the classification plate 16, a cylindrical second cylindrical portion 22 is also provided. This second cylindrical portion 22 faces the first cylindrical portion 20 and is spaced apart by a predetermined interval, with a gap 23 between them. Both the first cylindrical portion 20 and the second cylindrical portion 22 are arranged in the center of the classification chamber 18 in the W direction.

[0114] Similar to the airflow classifier 10 described above, the airflow classifier 10a maintains high precision and can further minimize the classification point compared to known technologies when classifying raw material powder with a particle size distribution into fine and coarse powders. Furthermore, the first cylindrical section 20 and the second cylindrical section 22 prevent larger coarse powder Pc from flowing into the fine powder recovery pipe 30, leaving the larger coarse powder Pc in the classification chamber 18. On the other hand, fine powder Pf, smaller than the classification point, passes through the gap 23 with the airflow and is attracted by the fine powder recovery pipe 30 via the fine powder discharge port 14a. This further reduces the particle size of the recovered fine powder Pf.

[0115] By setting the first cylindrical portion 20 and the second cylindrical portion 22, the grading points can be made smaller than those of known technologies.

[0116] (The third example of an air classifier)

[0117] Figure 5 This is a partial cross-sectional schematic diagram showing a third example of an airflow classifier according to an embodiment of the present invention.

[0118] exist Figure 5 In the air classifier 10b shown, with Figure 4 All components of the airflow classifier 10a shown are marked with the same symbol, and detailed descriptions are omitted.

[0119] Figure 5 The air classifier 10b shown is Figure 4 Compared to the airflow classifier 10a shown, the only difference is that the classifier 16 has a fine powder outlet 16b and is designed to remove fine powder Pf from the classifier 16; the other structures are the same. Figure 4 The airflow classifier 10a shown is the same.

[0120] The air classifier 10b has a groove 51 in a second region 26a surrounding the fine powder outlet 16b. A groove 50, facing the groove 51, is also provided in the first region 24a of the upper disc-shaped portion 14. In the air classifier 10b, the first region 24a of the upper disc-shaped portion 14 is the region facing the area surrounding the fine powder outlet 16b. Furthermore, the location of the groove 51 is only required to be within the second region 26a surrounding the fine powder outlet 16b, and is not necessarily limited to being located along the outer edge of the fine powder outlet 16b.

[0121] A fine powder recovery pipe 60 is installed at the fine powder discharge outlet 16b. (Refer to fine powder recovery pipe 30) Figure 4Similarly, the fine powder recovery pipe 60 is connected at its end (not shown) to an exhaust fan (not shown) via, for example, a bag filter (not shown). The bag filter (not shown) and the exhaust fan (not shown) constitute a fine powder recovery device. The fine powder recovery pipe 60 constitutes a fine powder recovery section. Fine powder Pf is recovered via the fine powder recovery pipe 60. The airflow classifier 10b can obtain... Figure 4 The air classifier 10a shown has the same effect.

[0122] exist Figure 5 In the structure of the coarse powder recovery section shown, fine powder Pf (refer to...) Figure 1 The coarse powder Pc (refer to) is discharged from side 16 of the grading plate, while the coarse powder Pc (refer to) is discharged from side 16 of the grading plate. Figure 1 From the side of the grading plate 16 and from the outer end 16a of the grading plate 16 and the housing 12 (refer to) Figure 1 The powder is discharged through the gap 39 (coarse powder outlet 66) between the annular walls 19.

[0123] In addition, the following methods can also be used: Figure 1 and Figure 4 As shown in the air classifiers 10 and 10a, the fine powder Pf is removed from the upper disc-shaped part 14, or as shown in the air classifier 10b, the fine powder Pf is removed from the classifying plate 16. There are no particular limitations on the removal of fine powder Pf in the air classifier.

[0124] (Example 4 of an air classifier)

[0125] Figure 6 This is a partial cross-sectional schematic diagram showing a fourth example of an airflow classifier according to an embodiment of the present invention.

[0126] exist Figure 6 In the air classifier 10c shown, with Figure 1 The components of the airflow classifier 10 shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0127] Figure 6 The air classifier 10c shown is Figure 1 Compared to the airflow classifier 10 shown, the only difference is that a first cylindrical portion 20 is provided in the upper disc-shaped portion 14, and a grooved portion 51 is provided in the classifying plate 16; the other structures are the same. Figure 1 The airflow classifier 10 shown is the same.

[0128] In the airflow classifier 10c, the upper disc-shaped part 14 is provided with a first cylindrical part 20 protruding into the classification chamber 18 along the edge of the fine powder outlet 14a.

[0129] The groove portion 51 is provided on the second field 26a of the classifying plate 16, which faces the first field 24a surrounding the fine powder outlet 14a. In the air classifier 10b, the first field 24a of the upper disc-shaped portion 14 faces the area surrounding the fine powder outlet 16b. No second cylindrical portion 22 is provided on the classifying plate 16. The air classifier 10c has a structure in which the upper disc-shaped portion 14 (one component) has a first cylindrical portion 20, and the classifying plate 16 (the other component) has a groove portion 51.

[0130] The 10c vortex classifier can obtain the same as... Figure 1 The air classifier 10 shown has the same effect.

[0131] The groove portion 51 can suppress powder adhesion into the classification chamber 18, enabling stable classification over a long period and maintaining classification accuracy. Furthermore, the first cylindrical portion 20 can suppress coarse powder Pc (see reference) with a larger particle size. Figure 1 ) flows into the fine powder recovery pipe 30 (refer to) Figure 1 Within this range, the size of the recovered fine powder Pf can be further reduced (refer to...). Figure 1 ) particle size.

[0132] (The 5th example of an air classifier)

[0133] Figure 7 This is a partial cross-sectional schematic diagram showing a fifth example of an airflow classifier according to an embodiment of the present invention.

[0134] exist Figure 7 In the air classifier 10d shown, with Figure 4 The components of the airflow classifier 10a shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0135] Figure 7 The air classifier 10d shown is Figure 4 Compared to the airflow classifier 10a shown, the only difference is that the first cylindrical section 20 is not provided, and the grooved section 51 is not provided on the classifying plate 16; the other structures are the same. Figure 4 The airflow classifier 10a shown is the same.

[0136] The airflow classifier 10d has a structure in which the classifying plate 16 (another component) has a second cylindrical portion 22 and the upper disc-shaped portion 14 (another component) has a groove portion 50.

[0137] A 10d air classifier can obtain the same as... Figure 1The airflow classifier 10 shown has the same effect. Furthermore, the groove section 50 can suppress powder adhesion into the classification chamber 18, enabling stable classification over a long period and maintaining classification accuracy over a long period.

[0138] Furthermore, the second cylindrical section 22 can suppress the flow of coarse powder Pc with a larger particle size into the fine powder recovery pipe 30 (see reference). Figure 1 Within this range, the particle size of the recovered fine powder Pf can be further reduced.

[0139] (The 6th example of an air classifier)

[0140] Figure 8 This is a partial cross-sectional schematic diagram showing a sixth example of an airflow classifier according to an embodiment of the present invention.

[0141] exist Figure 8 In the airflow classifier 10e shown, with Figure 4 The components of the airflow classifier 10a shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0142] Figure 8 The air classifier 10e shown is... Figure 4 Compared to the airflow classifier 10a shown, the only difference is that the diameter D1 of the first cylindrical section 20 and the diameter D2 of the second cylindrical section 22 are different; the other structures are the same. Figure 4 The air classifier 10a shown is the same. In the air classifier 10e, the diameter D1 of the first cylindrical section 20 is larger than the diameter D2 of the second cylindrical section 22.

[0143] The air classifier 10e can obtain the same as... Figure 4 The air classifier 10a shown has the same effect.

[0144] (The 7th example of an air classifier)

[0145] Figure 9 This is a partial cross-sectional schematic diagram showing the seventh example of an airflow classifier according to an embodiment of the present invention.

[0146] exist Figure 9 In the airflow classifier 10f shown, with Figure 4 The components of the airflow classifier 10a shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0147] Figure 9 The air classifier 10f shown is Figure 4 Compared to the airflow classifier 10a shown, the only difference is that the diameter D1 of the first cylindrical section 20 and the diameter D2 of the second cylindrical section 22 are different; all other structural features are the same. Figure 4The airflow classifier 10a shown is the same. Figure 9 The diameter D2 of the second cylindrical section 22 in the airflow classifier 10f shown is greater than the diameter D1 of the first cylindrical section 20.

[0148] The air classifier 10e can obtain the same as Figure 4 The air classifier 10a shown has the same effect.

[0149] (Example 8 of an air classifier)

[0150] Figure 10 This is a partial cross-sectional schematic diagram showing the eighth example of an airflow classifier according to an embodiment of the present invention.

[0151] exist Figure 10 In the air classifier shown, 10g of the sample contains the same amount of water as the sample. Figure 4 The components of the airflow classifier 10a shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0152] Figure 10 The air classifier shown is 10g and Figure 4 Compared to the airflow classifier 10a shown, the only difference is that an inclined portion 24b is formed in the first field 24a of the upper disc-shaped portion 14, and an inclined portion 26b is formed in the second field 26a of the classifying plate 16. All other structures are the same. Figure 4 The airflow classifier 10a shown is the same.

[0153] Figure 10 The airflow classifier 10g shown has an inclined portion 24b formed on the surface 14c of the upper disc-shaped portion 14 facing the classification chamber 18, and on the side close to the cylindrical first cylindrical portion 20. A groove portion 50 is provided in the inclined portion 24b.

[0154] An inclined portion 26b is formed on the surface 16c of the grading plate 16 facing the grading chamber 18, and on the side near the cylindrical second cylindrical portion 22. A groove portion 51 is provided in the inclined portion 26b.

[0155] Both inclined sections 24b and 26b are inclined planes formed by planes, with a straight cross-sectional shape. Both inclined sections 24b and 26b are inclined in a manner that gradually increases in height from the annular wall 19 toward the fine powder discharge outlet 14a and the classification chamber 18. In other words, the inclined section 24b of the upper disc-shaped section 14 rises toward the fine powder discharge outlet 14a. The inclined section 26b of the classification plate 16 descends toward the second cylindrical section 22.

[0156] By providing inclined portions 24b and 26b, the length L1 of the first cylindrical portion 20 and the length L2 of the second cylindrical portion 22 can be increased, thereby reducing the size of the recovered fine powder Pf (see reference). Figure 1 ) particle size.

[0157] The angles of the inclined portion 24b of the upper disc-shaped portion 14 relative to a line parallel to the W direction, and the angles of the inclined portion 26b of the classifying plate 16 relative to a line parallel to the W direction, are both represented by θ. Angle θ is preferably set between 5° and 30°, and more preferably between 10° and 20°. With angles between 5° and 30°, the classification points can be miniaturized when classifying the raw material powder Ps into fine powder Pf and coarse powder Pc. The angle θ of the inclined portion 24b of the upper disc-shaped portion 14 and the angle θ of the inclined portion 26b of the classifying plate 16 can be the same or different.

[0158] The surface 14c of the upper disc-shaped portion 14 can also be formed by an inclined surface extending from the periphery of the first cylindrical portion 20 to the outer edge of the upper disc-shaped portion 14. In other words, the surface 14c of the upper disc-shaped portion 14 can also be formed by an inclined surface. The surface 16c of the grading plate 16 can also be formed by an inclined surface extending from the periphery of the second cylindrical portion 22 to the outer edge of the grading plate 16. In other words, the surface 16c of the grading plate 16 can also be formed by an inclined surface.

[0159] Although the cross-sectional shapes of inclined portions 24b and 26b are straight lines as described above, the cross-sectional shapes do not necessarily have to be straight lines. They can also be curved, with the cross-sectional shape rising from the outside of the grading chamber 18 towards the center. That is, both inclined portions 24b and 26b can be constructed from curved surfaces, with the height increasing from the center of the grading chamber 18. Furthermore, inclined portions 24b and 26b can also employ a combination of planar and curved surfaces; in this case, the cross-sectional shape would be a combination of straight lines and curves.

[0160] Although the structure of the airflow classifier 10g has a first cylindrical section 20 and a second cylindrical section 22, it is not limited to this structure. It is sufficient to have at least one of the first cylindrical section 20 and the second cylindrical section 22.

[0161] Furthermore, regarding the inclined portion 24b and inclined portion 26b in the air classifier 10g, it is sufficient to have at least one of the inclined portion 24b and inclined portion 26b.

[0162] Furthermore, regarding the groove portion 50 and groove portion 51 in the air classifier 10g, it is sufficient to have at least one of the groove portion 50 and groove portion 51.

[0163] (The 9th example of an air classifier)

[0164] Figure 11 This is a partial cross-sectional schematic diagram showing the ninth example of an airflow classifier according to an embodiment of the present invention.

[0165] exist Figure 11In the air classifier shown, after 10 hours, with Figure 5 The components of the air classifier 10b shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0166] Figure 11 The air classifier 10h shown is Figure 5 Compared to the airflow classifier 10b shown, the only difference is that an inclined portion 26b is formed in the second field 26a of the classifying plate 16; all other structures are the same. Figure 5 The airflow classifier 10b shown is the same.

[0167] Figure 11 The airflow classifier 10h shown has a classifier plate 16 whose surface 16c facing the classifier chamber 18 is formed by an inclined portion 26b. The inclined portion 26b is a slope formed by planes, with a straight cross-sectional shape. The inclined portion 26b slopes from the annular wall 19 toward the fine powder discharge outlet 16b, that is, from the outside of the classifier chamber 18 toward the center, in a manner that the height of the classifier chamber 18 decreases. In other words, the surface 16c of the classifier plate 16 descends toward the outer end 16a. A groove 51 is provided in the inclined portion 26b, i.e., the inclined surface.

[0168] The angle of the inclined portion 26b of the grading plate 16 relative to a line parallel to the W direction of the upper disc-shaped portion 14 is denoted by β. The angle β is preferably set to 5° to 30°, and more preferably to 10° to 20°.

[0169] An air classifier can obtain the same results in 10 hours as... Figure 5 The air classifier 10b shown has the same effect.

[0170] Although the airflow classifier 10h has an inclined portion 26b on the surface 16c of the classifying plate 16, it is not limited to this structure. An inclined portion 24b may also be provided on the surface 14c of the upper disc-shaped portion 14 (see reference). Figure 10 In addition, it is permissible to have at least one of the inclined portion 24b and the inclined portion 26b.

[0171] Furthermore, although the structure of the airflow classifier 10h has a first cylindrical section 20 and a second cylindrical section 22, it is not limited to this structure, and it is sufficient to have at least one of the first cylindrical section 20 and the second cylindrical section 22.

[0172] exist Figure 11 In the structure of the coarse powder recovery section shown, fine powder Pf (not shown) is discharged from the side of the classifying plate 16, while coarse powder Pc (not shown) is discharged from the side of the classifying plate 16 and from the outer end 16a of the classifying plate 16 and the casing 12 (see reference). Figure 1 The powder is discharged through the gap 39 (coarse powder outlet 66) of the annular wall 19.

[0173] (Example 10 of an air classifier)

[0174] Figure 12 This is a partial cross-sectional schematic diagram showing a 10th example of an airflow classifier according to an embodiment of the present invention.

[0175] exist Figure 12 In the airflow classifier 10i shown, with Figure 11 The components of the air classifier 10h shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0176] Figure 12 The air classifier 10i shown is Figure 11 Compared to the airflow classifier 10h shown, the only difference is that it does not have a first cylindrical section 20; the other structures are the same. Figure 11 The airflow classifier shown is the same as the 10h type.

[0177] exist Figure 12 In the structure of the coarse powder recovery section shown, fine powder Pf (not shown) is discharged from the side of the classifying plate 16, while coarse powder Pc (not shown) is discharged from the side of the classifying plate 16 and from the outer end 16a of the classifying plate 16 and the casing 12 (see reference). Figure 1 The powder is discharged through the gap 39 (coarse powder outlet 66) of the annular wall 19.

[0178] An air classifier can obtain the same results in 10 hours as... Figure 1 The air classifier 10 shown has the same effect.

[0179] (Example 11 of an air classifier)

[0180] Figure 13 A schematic cross-sectional view showing the 11th example of an airflow classifier according to an embodiment of the present invention.

[0181] exist Figure 13 In the airflow classifier 10j shown, with Figure 1 The components of the airflow classifier 10 shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0182] Figure 13 The air classifier 10j shown is Figure 1 Compared to the air classifier 10 shown, the only difference is that the raw material supply section 40 has an injection section 54 and a guide vane 62 to replace the second air nozzle 36; the other structures are the same. Figure 1 The airflow classifier 10 shown is the same.

[0183] exist Figure 13In the airflow classifier 10j shown, a jetting section 54 is provided in the supply pipe 42 of the raw material supply section 40. The jetting section 54 has a jetting nozzle 55 for jetting raw material powder Ps into the classification chamber 18, and a pressure section 57 for supplying, for example, air at a high pressure to the jetting nozzle 55. The jetting nozzle 55 is connected to, for example, an upper disc-shaped section 14 via a pipe 56. Using the high-pressure air supplied from the pressure section 57 via the jetting nozzle 55 and the pipe 56, the raw material powder Ps in the raw material supply section 40 is supplied into the classification chamber 18 through the opening 42a of the upper disc-shaped section 14.

[0184] In the air classifier 10j, by providing the injection unit 54, the raw material powder Ps can be reliably supplied to the swirling flow generated in the classification chamber 18. Furthermore, the ejection nozzle 55 and pressure unit 57 of the injection unit 54 can be made from known powder conveying equipment.

[0185] In addition, Figure 13 In the airflow classifier 10j shown, with Figure 1 Similarly, the second air nozzle 36 in the airflow classifier 10 shown has a plurality of guide vanes 62 along the outer edge of the classification chamber 18. Furthermore, the guide vanes 62 are disposed on the annular wall 19 and are located below the first air nozzle 34 in the H direction. Like the first air nozzle 34, the guide vanes 62 each have a predetermined angle relative to the tangential direction of the outer edge of the classification chamber 18, and are arranged at equal intervals around the circumference of the classification chamber 18. The gas supply unit has the first air nozzle 34 and the guide vanes 62. The gas supply unit may also be structured without the first air nozzle 34, having only the guide vanes 62.

[0186] At the outer periphery of the plurality of guide vanes 62, there is a propulsion chamber 64 for accumulating air and supplying gas to the classification chamber 18. The propulsion chamber 64 is connected to a pressurized gas supply unit (not shown), from which gas at a predetermined pressure is supplied from the pressurized gas supply unit through the propulsion chamber 64 between the plurality of guide vanes 62. By supplying pressurized gas to the first air nozzle 34 and the guide vanes 62 respectively, a swirling flow is generated within the classification chamber 18.

[0187] In the air classifier 10j, the raw material powder Ps is centrifugally separated as it moves downwards and swirles inside the classification chamber 18. The guide vanes 62 are used to adjust the swirling speed of the raw material powder Ps during centrifugal separation. Each guide vane 62 is rotatably pivoted to the annular wall 19 via a rotating shaft (not shown) and secured to a rotating plate (not shown) by a locking pin (not shown). For example, the rotating plate can be rotated so that all the guide vanes 62 rotate simultaneously by a predetermined angle. By rotating the rotating plate to rotate all the guide vanes 62 by a predetermined angle, the spacing of each guide vane 62 can be adjusted, thereby changing the flow rate of gas, such as air, through the gaps between the guide vanes 62. This allows for changes in the classification performance, such as the classification points. Furthermore, by providing the guide vanes 62, the range of selectable classification points can be increased. Figure 13 The air classifier 10j shown can also obtain the same as Figure 1 The air classifier 10 shown has the same effect.

[0188] Although the air classifier 10j has a spray section 54, the air classifiers 10, 10a to 10i described above may also have a spray section 54.

[0189] Furthermore, although the structure of the raw material supply unit 40 is configured to be connected to the upper disc-shaped part 14 to supply the raw material powder Ps through the opening 42a of the upper disc-shaped part 14 to the swirling flow generated in the classification chamber 18, it is not limited to this structure. For example, a structure in which the raw material supply unit 40 is connected to the classification plate 16 to supply the raw material powder Ps to the swirling flow generated in the classification chamber 18 can also be adopted.

[0190] Furthermore, in the structure of the air classifier 10j, guide vanes 62 are installed to replace... Figure 1 The second air nozzle 36 shown in the air classifier 10 is not limited to this structure. In the air classifier structures of the 2nd to 11th examples of the air classifier described above, guide vanes 62 may also be provided instead of the second air nozzle 36.

[0191] The present invention is basically constructed as described above. The airflow classifier of the present invention has been described in detail above; however, the present invention is not limited to the embodiments described above, and various modifications or alterations can be made without departing from the spirit of the present invention.

[0192] [Example]

[0193] The following will describe in more detail the use of the airflow classifier of the present invention for classifying operations.

[0194] Using the above Figure 4 The air classifier 10a shown, and Figure 14 The first airflow classifier 100 shown for comparison classifies the raw material powder.

[0195] Figure 14 A schematic cross-sectional view is shown to illustrate the first airflow classifier used for comparison. Figure 14 In the first airflow classifier 100 shown, with Figure 4 The components of the airflow classifier 10a shown are all marked with the same symbol, and their detailed descriptions are omitted.

[0196] Figure 14 The first airflow classifier 100 shown is Figure 4 Compared to the air classifier 10a shown, the only difference is that it does not have grooves 50 and 51; the other structures are the same. Figure 4 The airflow classifier 10a shown is the same.

[0197] Both the airflow classifier 10a of the present invention and the first airflow classifier 100 used for comparison perform classification processing under the same classification conditions such as air volume.

[0198] The raw material powder uses ceramic particles with an average particle size of 0.4 μm. Furthermore, the average particle size is a value determined using laser diffraction and scattering.

[0199] The grading results are marked as follows: Figure 15 Statistical charts. In addition... Figure 16 To show the ceramic particles after classification using an air classifier 10a. Figure 17 To display ceramic particles after classification using the first airflow classifier 100. Figure 16 and Figure 17 It is an image from a scanning electron microscope (SEM) with a magnification of 10,000x.

[0200] Figure 15 The symbol 70 in the middle represents Figure 4 The classification results of the air classifier 10a shown are indicated by symbol 72. Figure 14 The classification results of the first airflow classifier 100 are shown. Figure 15 As shown, the grading accuracy is high, and this invention can make the grading points smaller. Figure 16 and Figure 17As shown, it can be seen that the amount of coarse particles after classification by the first airflow classifier 100 is greater than that of the airflow classifier 10a. Furthermore, it can be confirmed that the first airflow classifier 100, used for comparison, has a greater amount of powder adhering to the first cylindrical portion 20 than the airflow classifier 10a.

[0201] Figure 18 This is a partial cross-sectional schematic diagram of a second airflow classifier used for comparison. Figure 18 In the second airflow classifier 102 shown, with Figure 10 The components of the air classifier shown in the diagram (10g) are all marked with the same symbol, and their detailed descriptions are omitted. Figure 18 The second airflow classifier 102 shown is Figure 10 Compared to the air classifier 10g shown, the only difference is that it does not have grooves 50 and 51; the rest of the structure is the same. Figure 10 The air classifier shown is the same as the 10g one.

[0202] Both the airflow classifier 10g of the present invention and the second airflow classifier 102 used for comparison perform classification processing under the same classification conditions such as air volume.

[0203] The raw material powder uses ceramic particles with an average particle size of 0.4 μm. Furthermore, the average particle size is a value determined using laser diffraction and scattering.

[0204] The grading results are marked as follows: Figure 19 Statistical charts. In addition... Figure 20 To show the ceramic particles after being classified using an air classifier with 10g of material. Figure 21 To display the ceramic particles after classification using the second airflow classifier 102. Figure 20 and Figure 21 To display images from a scanning electron microscope with a magnification of 10,000x.

[0205] exist Figure 19 The symbol 74 in the text represents Figure 10 The classification result of 10g of air classifier shown is given by symbol 76. Figure 18 The classification results of the second airflow classifier 102 are shown. Figure 19 As shown, the grading accuracy is high, and this invention can make the grading points smaller. Figure 20 and Figure 21 As shown, it can be seen that the amount of coarse particles after classification by the second air classifier 102 is greater than that of the air classifier 10g. In addition, it can also be confirmed that the amount of powder adhering to the first cylindrical part 20 by the second air classifier 102 used for comparison is greater than that of the air classifier 10g.

Claims

1. An airflow classifier, characterized in that, have: The housing has a top wall and an annular wall continuously disposed along the outer edge of the top wall; A grading plate is configured such that its surface faces the top wall of the housing; A grading chamber is formed between the top wall of the housing and the surface of the grading plate; The gas supply unit supplies gas to the grading chamber to generate a swirling flow; The raw material supply unit supplies raw material powder to the swirling flow occurring in the classification chamber; The fine powder outlet is located at the center of one of the top wall of the housing that constitutes the grading chamber and the surface of the grading plate; A coarse powder discharge outlet is located on either side of the ceiling wall and the surface of the grading plate opposite to the ceiling wall, and forms an opening along the outer periphery of the grading chamber; and The groove is provided on at least one of the surfaces of the ceiling wall and the grading plate.

2. The airflow classifier as described in claim 1, characterized in that, It also has at least one of a first cylindrical portion and a second cylindrical portion. The first cylindrical portion is located at the fine powder outlet; The second cylindrical portion is disposed on the surface of the grading plate in the grading chamber and faces the first cylindrical portion with a predetermined gap.

3. The airflow classifier as described in claim 2, characterized in that, The diameter of the first cylindrical portion is different from the diameter of the second cylindrical portion.

4. The airflow classifier as described in claim 1, characterized in that, An inclined surface is formed on at least one of the top wall of the housing and the surface of the grading plate, and the groove is provided on the inclined surface.

5. The airflow classifier as described in claim 2, characterized in that, An inclined surface is formed on at least one of the periphery of the first cylindrical portion of the top wall of the housing and the periphery of the second cylindrical portion of the surface of the grading plate, and the groove portion is provided on the inclined surface.

6. The airflow classifier as described in any one of claims 1 to 5, characterized in that, The fine powder outlet is circular, and the groove is configured to form a concentric circle relative to the fine powder outlet.

7. The airflow classifier as described in any one of claims 1 to 5, characterized in that, The groove is provided on the surface of the ceiling wall and the grading plate.

8. The airflow classifier as described in claim 7, characterized in that, The fine powder outlet is circular, and the groove is arranged to form a concentric circle with respect to the fine powder outlet. The groove on the ceiling wall is opposite to the groove on the surface of the grading plate.

9. The airflow classifier as described in claim 7, characterized in that, On the side of the ceiling wall and the grading plate where the fine powder outlet is located, the groove portion is arranged in a concentric circle around the fine powder outlet; and on the side where the fine powder outlet is not located, a concentric circle groove portion is provided opposite to the concentric circle groove portion arranged in the area surrounding the fine powder outlet. The concentric circular groove portion provided on the side having the fine powder outlet, and the concentric circular groove portion provided on the side not having the fine powder outlet, are located at the same position in a direction orthogonal to the direction facing each other of the top wall of the housing of the grading chamber and the surface of the grading plate.

10. The airflow classifier as described in any one of claims 1 to 5, characterized in that, A plurality of grooves are provided around the fine powder outlet.

11. The airflow classifier as described in claim 2, characterized in that, The ceiling wall has the first cylindrical portion, and the grading plate has the groove portion on its surface.

12. The airflow classifier as described in claim 2, characterized in that, The surface of the grading plate has the second cylindrical portion, and the groove portion is provided on the ceiling wall.

13. The airflow classifier as described in claim 4 or 5, characterized in that, The ramp slopes in a manner that the outside of the grading chamber faces toward the center and the height of the grading chamber gradually increases.

14. The airflow classifier as described in claim 4 or 5, characterized in that, The ramp slopes in a manner that it is inclined from the outside of the grading chamber toward the center and the height of the grading chamber decreases.

15. The airflow classifier as described in any one of claims 1 to 5, 11 and 12, characterized in that, The raw material supply unit is connected to either the top wall of the housing constituting the classification chamber or the surface of the classification plate, and supplies the raw material powder to the swirling flow that occurs within the classification chamber.

16. The airflow classifier as described in any one of claims 1 to 5, 11 and 12, characterized in that, The raw material supply unit has a nozzle for dispensing the raw material powder into the swirling flow generated in the classification chamber.

17. The airflow classifier as described in any one of claims 1 to 5, 11 and 12, characterized in that, The gas supply unit has a plurality of air nozzles, each air nozzle being arranged along the outer edge of the classification chamber and at equal intervals in the circumferential direction of the classification chamber.

18. The airflow classifier as described in any one of claims 1 to 5, 11 and 12, characterized in that, The gas supply section has a plurality of guide vanes, each guide vane being arranged along the outer edge of the classification chamber and at equal intervals in the circumferential direction of the classification chamber.

Images