Air flow type classifier

Abstract

The invention provides an air flow type classifier with a small classification point. An air-flowing classifier is provided with: a housing having a top wall and an annular wall continuously provided on the outer edge of the top wall; a classification plate having a surface facing the top wall of the housing; a classification chamber formed between a top wall of the housing and a surface of the classification plate; a gas supply unit that supplies gas into the classification chamber and generates a swirling flow; the gas suction part sucks gas in the classification chamber from the outer edge of the classification chamber; a raw material supply unit for supplying a raw material powder to the swirling flow generated in the classification chamber; a fine powder discharge port provided in the center of one of the top wall of the housing constituting the classification chamber and the surface of the classification plate; and a coarse powder discharge port that opens along the outer periphery of the classification chamber on either the top wall or the surface of the classification plate facing the top wall.

Description

TECHNICAL FIELD

[0001] The present application relates to an air flow type classifier which classifies a raw powder having a particle size distribution into a fine powder and a coarse powder at a desired particle diameter (classification point) by utilizing a balance of centrifugal force and resistance applied to the powder by a rotational flow formed by a gas, and particularly relates to an air flow type classifier which maintains classification accuracy and makes the classification point smaller. BACKGROUND

[0002] At present, oxide fine particles, nitride fine particles, carbide fine particles, and the like are used in the fields of electrically insulating materials such as semiconductor substrates, printed substrates, and various electrically insulating components, high-hardness high-precision mechanical working materials such as cutting tools, dies, and bearings, functional materials such as humidity sensors, the production of sintered bodies such as precision sintering molding materials, the production of spraying components such as materials requiring high-temperature wear resistance such as engine valves, and even the fields of electrodes, electrolyte materials, and various catalysts of fuel cells. By using such fine particles, the joining strength and the density of different kinds of ceramics to each other or different kinds of metals to each other, and even the functionality, are improved in sintered bodies, spraying components, and the like.

[0003] The above fine particles are produced by a chemical method in which various gases and the like are chemically reacted at high temperatures, or a physical method in which a substance is decomposed and evaporated by irradiation of an electron beam or a laser beam, and the like. In the above production methods, the produced fine particles have a particle size distribution, and coarse powders and fine powders are mixed together. In the case of fine particles used in the above uses, the one having a smaller proportion of coarse powders is preferable because good characteristics can be obtained in the field of using fine particles. Further, in the case of metal fine particles, the one having a smaller proportion of coarse powders is also preferable because good characteristics can be obtained in the field of using metal fine particles.

[0004] Therefore, for example, an air flow type classifier and a powder classifying device, and the like, which use a rotational flow, are used to centrifugally separate coarse powders and fine powders by applying a rotational motion to a powder.

[0005] For example, in Patent Literature 1, a powder classifying device is described which classifies a powder having a particle size distribution by air flow transportation and supply. The powder classifying device of Patent Literature 1 has: a hollowed-out cavity (a disc-shaped hollowed-out cavity portion) which is a space for classifying the supplied powder having a particle size distribution, a powder supply port which supplies the powder having a particle size distribution to the disc-shaped hollowed-out cavity portion, a plurality of guide vanes which are arranged to extend in an inner direction at a prescribed angle from the outer periphery of the disc-shaped hollowed-out cavity portion, an air flow discharge portion which includes fine powder discharged from the disc-shaped hollowed-out cavity portion, and a coarse powder recovery portion which recovers coarse powder from the disc-shaped hollowed-out cavity portion, and has a plurality of air nozzles which are arranged on the tangential direction of the outer peripheral wall of the disc-shaped hollowed-out cavity portion below the plurality of guide vanes, and which blow compressed air toward the coarse powder recovery portion side of the disc-shaped hollowed-out cavity portion, so as to return the fine powder of the coarse powder recovery portion side to the disc-shaped hollowed-out cavity portion.

[0006] In addition, in Patent Literature 2, a classifying device is described which guides a powder supplied from a supply port provided at the upper portion of a device main body in a downward direction while rotating within the device main body, and has a suction port at the upper end in the central portion of the device main body, and a suction pipe composed of multiple pipes is provided, and the powder having a smaller particle diameter among the powder guided in the downward direction while rotating is sucked from the suction port through the suction pipe.

[0007] In Patent Literature 2, the powders having different particle diameters are respectively sucked and recovered by the suction pipe composed of multiple pipes.

[0008] Prior Art Documents

[0009] Patent Literature

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

[0011] Patent Literature 2: Japanese Patent Application Laid-Open No. 2000-107698 SUMMARY

[0012] Technical problem to be solved by the invention

[0013] In the powder classifying device of Patent Literature 1, a raw material powder having a particle size distribution can be classified into fine powder and coarse powder at a desired particle diameter (classification point), but recently, the particle diameter of the fine powder required has become smaller, and in the powder classifying device, further miniaturization of the classification point is desired.

[0014] Further, in Patent Literature 2, one raw material powder is classified by one classification operation, and the powders having different particle diameters are respectively recovered by the suction pipe composed of multiple pipes.

[0015] Therefore, in Patent Document 2, although the powder can be recovered separately through each tube constituting the multi-tube structure, and the deviation of the particle size of the recovered individual powder can be reduced, the classification point is determined by the airflow balance of each suction tube, and the miniaturization of the classification point cannot be achieved.

[0016] The purpose of this invention is to provide an airflow classifier with a smaller classification point.

[0017] Means for solving the technical problem

[0018] To achieve the above objectives, the invention [1] is: an airflow classifier comprising: a housing having a top wall and an annular wall continuously disposed on the outer edge of the top wall; a classifying plate having its surface facing the top wall of the housing; a classifying chamber being formed between the top wall of the housing and the surface of the classifying plate; a gas supply unit supplying gas into the classifying chamber to generate a rotating flow; a gas suction unit suctioning gas from the outer edge of the classifying chamber; a raw material supply unit supplying raw material powder to the rotating 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 surface of the classifying plate; and a coarse powder outlet opening along the outer periphery of the classifying chamber on either side of the top wall and the surface of the classifying plate facing the top wall.

[0019] The invention [2] is as follows: the airflow classifier described in the invention [1] further includes: other gas suction parts, which attract gas from the gap communicating with the classification chamber between the outer end of the classification plate and the annular wall of the shell.

[0020] The invention [3] is: an airflow classifier comprising: a housing having a top wall and an annular wall continuously disposed on the outer edge of the top wall; a classifying plate having its surface facing the top wall of the housing; a classifying chamber being formed between the top wall of the housing and the surface of the classifying plate; a gas supply unit for supplying gas into the classifying chamber to generate a rotating flow; a gas suction unit for suctioning gas in a gap communicating with the classifying chamber between the outer end of the classifying plate and the annular wall of the housing; a raw material supply unit for supplying raw material powder to the rotating flow generated in the classifying chamber; a fine powder outlet being disposed at the center of one of the top wall of the housing constituting the classifying chamber and the surface of the classifying plate; and a coarse powder outlet being opened along the outer periphery of the classifying chamber on either side of the top wall and the surface of the classifying plate facing the top wall.

[0021] The invention [4] is: an airflow classifier as described in any of the inventions [1] to [3], wherein the gas supply unit has a plurality of air nozzles that supply gas into the classifying chamber to generate a rotating flow, and each air nozzle is arranged at equal intervals along the outer edge of the classifying chamber in the circumferential direction of the classifying chamber.

[0022] The invention [5] is: an airflow classifier as described in any of the inventions [1] to [4], wherein the gas suction unit has one or more suction nozzles to attract gas in the tangential direction of the rotating flow in the classification chamber.

[0023] The invention [6] is: an airflow classifier as described in the invention [5], wherein the gas suction unit has a plurality of suction nozzles that attract gas in the tangential direction of the rotating flow in the classification chamber and are arranged at equal intervals in the circumferential direction of the classification chamber.

[0024] The invention [7] is: an airflow classifier as described in any of the inventions [1] to [6], further comprising: a groove portion disposed on at least one of the top wall and the surface of the classifying plate; and at least one of a first cylindrical portion and a second cylindrical portion, wherein the first cylindrical portion is disposed at the micro powder outlet, and the second cylindrical portion is opposite to the first cylindrical portion and disposed on the surface of the classifying plate of the classifying chamber with a predetermined gap.

[0025] The invention [8] is: an airflow classifier as described in the invention [7], wherein 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 classifying plate is formed with an inclined surface; and a groove is provided on the inclined surface.

[0026] The invention [9] is an airflow classifier as described in the invention [8], wherein the inclined plane slopes from the outside of the classifying chamber toward the center in such a way that the height of the classifying chamber gradually increases.

[0027] The invention

[10] is: an airflow classifier as described in any of the inventions [1] to [9], wherein, on the surface of the top wall and the classifying plate, a groove is provided on the side with a micro powder outlet, the groove being concentric with the micro powder outlet along the periphery of the micro powder outlet; a concentric groove is provided on the side without a micro powder outlet, the groove being opposite to the concentric groove provided in the area surrounding the micro powder outlet; the concentric groove provided on the side with the micro powder outlet and the concentric groove provided on the side without the micro powder outlet are positioned in the same direction orthogonal to the direction opposite to the top wall of the classifying chamber and the surface of the classifying plate.

[0028] The invention

[11] is an airflow classifier as described in any of the inventions [1] to

[10] , wherein a raw material supply unit is connected to either the top wall of the shell constituting the classification chamber or the surface of the classification plate, thereby supplying raw material powder to the rotating flow generated in the classification chamber.

[0029] The invention

[12] is: an airflow classifier as described in the invention

[11] , wherein the raw material supply section has an ejector nozzle that supplies raw material powder to the rotating flow generated in the classification chamber.

[0030] Effects of the invention

[0031] According to the present invention, when classifying raw material powder with particle size distribution into micro powder and coarse powder, the classification point can be made smaller than before. Attached Figure Description

[0032] Figure 1 This is a schematic cross-sectional view illustrating a first example of an airflow classifier according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic top view of an example of the trough section of a first example of an airflow classifier according to an embodiment of the present invention.

[0034] Figure 3 This is a schematic top view illustrating a first example of an airflow classifier according to an embodiment of the present invention, and other examples of the trough.

[0035] Figure 4 This is a schematic top view illustrating the configuration of the air nozzle and the suction nozzle in a first example of an airflow classifier according to an embodiment of the present invention.

[0036] Figure 5 This is a schematic cross-sectional view illustrating a second example of an airflow classifier according to an embodiment of the present invention.

[0037] Figure 6 This is a schematic cross-sectional view illustrating a third example of an airflow classifier according to an embodiment of the present invention.

[0038] Figure 7 A chart to represent the results of the grading.

[0039] Figure Labels

[0040] 10, 10a, 10b Airflow classifier; 12 Shell; 12a Surface; 13 Top wall; 13b Outer edge; 14 Upper disc-shaped part; 14a, 16b Micro powder outlet; 16 Classification plate; 16a Outer end; 18 Classification chamber; 18c Outer edge; 19 Annular wall; 19a Surface; 20 First cylindrical part; 22 Second cylindrical part; 23 Gap; 24a First region; 24b Inclined part; 26a Second region; 26b Inclined part; 28 Coarse powder Final recovery chamber; 30 Micro powder recovery pipe; 30c end; 34 First air nozzle; 36 Suction nozzle; 38 Second air nozzle; 39 Gap; 40 Raw material supply section; 42 Supply pipe; 43 Pipe; 44 Connecting section; 50, 51, 52 Groove section; 54 Injector section; 55 Ejection nozzle; 56 Piping; 60 Coarse powder discharge port; 62 Guide vane; 64 Pressing chamber; H, W direction; Pc coarse powder; Pf micro powder; Ps raw material powder; θ angle. Detailed Implementation

[0041] Hereinafter, the airflow classifier of the present invention will be described in detail based on the suitable embodiments shown in the accompanying drawings.

[0042] Furthermore, the figures described below are exemplary figures used to illustrate the present invention, and the present invention is not limited to the figures shown below.

[0043] In the following text, the "~" indicating a range of values ​​includes the values ​​written on both sides. For example, if ε is the value εα to the value εβ, then the range of ε includes the values ​​εα and εβ, which can be represented in mathematical notation as εα≦ε≦εβ.

[0044] Furthermore, unless otherwise specified below, "arbitrary angle", "perpendicular", "orthogonal" and "parallel" include the generally permissible range of error.

[0045] (The first example of an air classifier)

[0046] Figure 1 This is a schematic cross-sectional view illustrating a first example of an airflow classifier according to an embodiment of the present invention. Figure 2 This is a schematic top view showing an example of the trough portion of a first example of an airflow classifier according to an embodiment of the present invention. Figure 3 This is a schematic top view illustrating a first example of an airflow classifier according to an embodiment of the present invention, and other examples of the trough.

[0047] Figure 4 This is a schematic top view illustrating the configuration of the air nozzle and the suction nozzle in a first example of an airflow classifier according to an embodiment of the present invention.

[0048] Figure 1The airflow classifier 10 shown utilizes the balance between centrifugal force and resistance applied to the powder by a rotating flow formed by gas to classify the raw material powder Ps with particle size distribution into fine powder Pf and coarse powder Pc at the desired particle size (classification point).

[0049] 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, in plan view, forms a circular upper disc-shaped portion 14, and the housing 12 has this upper disc-shaped portion 14. A classifying plate 16 is arranged opposite the top wall 13, i.e., the upper disc-shaped portion 14, with a predetermined interval between it and the top wall 13. The classifying plate 16 is approximately circular in plan view. The upper disc-shaped portion 14 (top wall 13) and the classifying plate 16 are arranged opposite each other with respect to direction H. Furthermore, the surface 12a of the housing 12 is planar, and direction H is perpendicular to the surface 12a (planar) of the housing 12. Direction W is orthogonal to direction H and parallel to the surface 12a (planar) of the housing 12. The plan view represents the view from direction H.

[0050] A roughly disc-shaped grading chamber 18, viewed from above, is divided and formed between the upper disc-shaped portion 14 and the grading plate 16. The outer periphery of the grading chamber 18 is closed by the annular wall 19 of the housing 12. Thus, the grading chamber 18 is a space sandwiched between the opposing top wall 13 (the surface 14c of the upper disc-shaped portion 14) and the surface 16c of the grading plate 16, and the grading chamber 18 is formed between the top wall 13 of the housing 12 and the surface 16c of the grading plate 16. Thus, both the upper disc-shaped portion 14 (top wall 13) and the grading plate 16 are components constituting the space of the grading chamber 18. Figure 1 In the configuration shown, the surface 19a of the annular wall 19 of the shell 12 is the outer edge 18c of the grading chamber 18. The outer edge 18c of the grading chamber 18 constitutes the wall surface of the grading chamber 18. The wall surface of the grading chamber 18 is a surface parallel to the direction H.

[0051] In the classification chamber 18, raw material powder Ps with particle size distribution is separated into coarse powder Pc and fine powder Pf, etc., and thus classified.

[0052] A micro powder outlet 14a is formed in the center of the upper disc-shaped portion 14 in the direction W. The micro powder outlet 14a is connected to the classification chamber 18. The micro powder outlet 14a is circular, for example, when viewed from above. As will be described later, the micro powder outlet 14a discharges the micro powder Pf from the coarse powder Pc and micro powder Pf generated by separating the raw material powder Ps in the classification chamber 18.

[0053] The system includes a gas supply section that supplies gas into the classification chamber 18 to generate a rotating flow, and a gas suction section that draws gas from the outer edge 18c of the classification chamber 18. The gas supply section and the gas suction section will be described later. The gas supply section has a plurality of first air nozzles 34 (air nozzles) that supply gas into the classification chamber 18 to generate a rotating flow. The configuration of the gas suction section is not particularly limited as long as it can draw gas from the outer edge 18c of the classification chamber 18. The gas suction section can draw gas from the outer edge 18c of the classification chamber 18 in any direction relative to the wall of the classification chamber 18. For example, it can draw gas in a direction perpendicular to the wall of the classification chamber 18 (i.e., in the direction of direction W), or it can draw gas in the tangential direction of the rotating flow within the classification chamber 18. Preferably, the gas suction section that draws gas in the tangential direction of the rotating flow within the classification chamber 18 has one or more suction nozzles 36, but there may also be only one suction nozzle 36. In the case of having a plurality of suction nozzles 36, they are preferably arranged at equal intervals in the circumferential direction of the classifying chamber 18.

[0054] The airflow classifier 10 has a first cylindrical portion 20 protruding into the classification chamber 18 along the edge of the micropowder outlet 14a on the upper disc-shaped portion 14. The first cylindrical portion 20 is, for example, constructed from a cylindrical component having an inner diameter identical to that of the micropowder outlet 14a. The first cylindrical portion 20 communicates with the micropowder outlet 14a. A cylindrical second cylindrical portion 22 is disposed on the classification plate 16, which is another component, facing the first cylindrical portion 20 and spaced apart by a predetermined interval to create a gap 23. The first cylindrical portion 20 and the second cylindrical portion 22 are positioned at the center of the classification chamber 18 in the direction W.

[0055] The air classifier 10 has a groove 50 provided in a first region 24a around the micro powder outlet 14a in the upper disc-shaped portion 14. The groove 50 is configured to be recessed relative to the surface 14c of the upper disc-shaped portion 14.

[0056] For example, groove 50 Figure 2 As shown, along the outer edge of the first cylindrical portion 20 (the periphery of the micro powder outlet 14a), it is arranged in a concentric circle with the micro powder outlet 14a. In the top wall 13 (upper disc-shaped portion 14) where the micro powder outlet 14a is provided, a groove portion 50 is provided, which is concentric with the micro powder outlet 14a along the periphery of the micro powder outlet 14a.

[0057] In the grading plate 16, a groove 51 is provided along the periphery of the second cylindrical portion 22 in a second region 26a opposite to the first region 24a (periphery of the micro powder discharge port 14a) of the first cylindrical portion 20. The groove 51 is recessed relative to the surface 16c of the grading plate 16. In components without openings (e.g., the grading plate 16), a groove 51 concentrically arranged with the second cylindrical portion 22 is provided, opposite to a concentrically arranged groove 50 provided in the region surrounding the micro powder discharge port 14a. The groove 51 and the groove 50 have the same configuration.

[0058] The groove 50 of the upper disc-shaped portion 14 and the groove 51 of the classifying plate 16 are arranged facing each other in the direction H. For example, the groove 50 of the upper disc-shaped portion 14 (one component) which is concentric with the micro powder outlet 14a and the groove 51 of the classifying plate 16 (the other component) which is concentric with the second cylindrical portion 22 are arranged in the same position in the direction W, which is orthogonal to the direction H of the two components of the classifying chamber 18 facing each other, the upper disc-shaped portion 14 and the classifying plate 16.

[0059] Both groove 50 and groove 51 have a rectangular cross-sectional shape. However, the cross-sectional shape of groove 50 and groove 51 is not limited to a rectangular shape; it can also be a flat, curved, or bent surface at the bottom. For example, the cross-sectional shape of groove 50 and groove 51 can also be a U-shape or a V-shape.

[0060] The groove 51 and the groove 50 have the same configuration, and their width in the direction W and their depth in the direction H are the same, but this is not a limitation. The groove 50 and the groove 51 may also have different widths in the direction W and different depths in the direction H.

[0061] As described above, the grooves 50 and 51 are, for example, Figure 2 As shown, it is configured to be concentric with the micro powder discharge port 14a, but is not limited to this. For example, as Figure 3 As shown, the configuration may also include a plurality of grooves 52 arranged around the micropowder discharge port 14a. For example, the opening of the groove 52 is circular in plan view.

[0062] Alternatively, the groove can be provided in at least one of the two components constituting the classification chamber 18: the opposing upper disc-shaped portion 14 and the classification plate 16. That is, it can also be configured such that at least one of the first region 24a surrounding the micro powder discharge port 14a and the second region 26a surrounding the micro powder discharge port 14a and opposite to the first region 24a has a groove that is recessed relative to the surface 14c of the upper disc-shaped portion 14 or the surface 16c of the classification plate 16.

[0063] like Figure 1 As shown, the inclined portion 24b is formed in the first region 24a of the upper disc-shaped portion 14, while the inclined portion 26b is formed in the second region 26a of the grading plate 16.

[0064] In the airflow classifier 10, an inclined portion 24b is formed on the surface 14c of the upper disc-shaped portion 14 facing the classification chamber 18, near the cylindrical first cylindrical portion 20. A groove 50 is provided in the inclined portion 24b. That is, the groove 50 is provided on the inclined surface.

[0065] An inclined portion 26b is formed on the surface 16c of the grading plate 16 facing the grading chamber 18, near the cylindrical second cylindrical portion 22. A groove 51 is provided in the inclined portion 26b. That is, the groove 51 is provided on the inclined surface.

[0066] Inclined portions 24b and 26b are inclined surfaces formed by planes, with a straight cross-sectional shape. Inclined portions 24b and 26b slope from the annular wall 19 towards the micropowder discharge outlet 14a, gradually increasing in height towards the classification chamber 18. That is, the inclined portion 24b of the upper disc-shaped portion 14 rises from the annular wall 19 towards the micropowder discharge outlet 14a. The inclined portion 26b of the classification plate 16 descends from the annular wall 19 towards the second cylindrical portion 22. The height of the classification chamber 18 is the distance in the direction H of the classification chamber 18.

[0067] By setting 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, and the shrinkage of the recovered micro powder Pf can be reduced (see reference). Figure 1 The particle size is determined by the length L1 of the first cylindrical section 20 and the length L2 of the second cylindrical section 22. These lengths are in directions parallel to the direction H.

[0068] The angles relative to the inclined portion 24b parallel to the direction W of the upper disc-shaped portion 14 and the angles relative to the line parallel to the direction W of the inclined portion 26b of the classifying plate 16 are both denoted by θ. The angle θ is preferably 5° to 30°, and more preferably 10° to 20°. If the angle θ is between 5° and 30°, the classification points can be minimized when the raw material powder Ps is classified into fine powder Pf and coarse powder Pc.

[0069] 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 grading plate 16 can be the same or different.

[0070] The surface 14 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. That is, 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. That is, the surface 16c of the grading plate 16 can also be formed by an inclined surface.

[0071] As described above, the inclined portions 24b and 26b have a straight cross-sectional shape, but the cross-sectional shape does not have to be a straight line. They can be formed by curved surfaces that increase in height from the outside of the grading chamber 18 towards the center. In other words, the inclined portions 24b and 26b can be formed by curved surfaces that increase in height from the center of the grading chamber 18, and their cross-sectional shape can also be curved. Furthermore, the inclined portions 24b and 26b can be a combination of planar and curved surfaces. In this case, the cross-sectional shape is a combination of straight and curved lines.

[0072] The airflow classifier 10 has a first cylindrical section 20 and a second cylindrical section 22, but is not limited thereto, as long as it has at least one of the first cylindrical section 20 and the second cylindrical section 22.

[0073] Furthermore, in the airflow classifier 10, regarding the inclined portion 24b and the inclined portion 26b, it is sufficient to have at least one of the inclined portion 24b and the inclined portion 26b.

[0074] By setting the grooves 50 and 51, the classification point can be reduced. That is, it is possible to classify the powder into fine and coarse powder at a smaller particle size. Furthermore, by setting the grooves 50 and 51, the velocity of the powder flowing from outside the device to the fine powder discharge port 14a can be locally suppressed, thus reducing the classification point. In this way, it is possible to classify the powder into fine and coarse powder at a smaller particle size.

[0075] As described above, the airflow classifier 10 is configured with a groove 50 in the upper disc-shaped portion 14 and a groove 51 in the classifying plate 16, but it is not limited to this configuration. It may also be configured to have a groove in at least one of the groove 50 in the upper disc-shaped portion 14 and the groove 51 in the classifying plate 16. Furthermore, the airflow classifier 10 may also be configured to lack both the groove 50 in the upper disc-shaped portion 14 and the groove 51 in the classifying plate 16.

[0076] In the micro powder discharge port 14a, the micro powder recovery pipe 30 is provided extending in a direction perpendicular to the surface 12a (plane) of the housing 12. This perpendicular direction is parallel to the direction H mentioned above.

[0077] The micro powder recovery pipe 30 is used to discharge the gas containing the micro powder Pf classified in the classification chamber 18 through the gap 23 to the outside of the classification chamber 18. For example, at the end 30c opposite to the classification chamber 18, the micro powder recovery pipe 30 is connected to a suction blower (not shown) via a bag filter (not shown). The bag filter (not shown) and the suction blower (not shown) constitute a micro powder recovery device. Furthermore, the micro powder recovery pipe 30 constitutes a micro powder recovery section. The coarse powder Pc and the micro powder Pf generated from the separation of the raw material powder Ps in the classification chamber 18 are discharged from the micro powder discharge port 14a of the upper disc-shaped section 14.

[0078] Furthermore, a gap 39 exists 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 and is connected to the grading chamber 18. The connecting portion 44 between the gap 39 and the grading chamber 18 is also the outer edge 18c of the grading chamber 18. The outer edge of the grading chamber 18 is further outward in the W direction than the outer edge 18c of the grading chamber 18, that is, in the region on the side of the housing 12.

[0079] Below the housing 12, for example, a hollow frustum-shaped coarse powder recovery chamber 28 is provided. The classification chamber 18 and the coarse powder recovery chamber 28 are connected by a gap 39. Furthermore, the outer edge of the classification chamber 18 is higher in the direction H than the central part, and the outer edge of the classification chamber 18 is wider in the direction H.

[0080] The coarse powder recovery chamber 28 is used to discharge the coarse powder Pc classified in the classification chamber 18 to the outside of the classification chamber 18. A coarse powder recovery pipe (not shown) is provided in the coarse powder recovery chamber 28 to collect the classified coarse powder. At the lower end of the coarse powder recovery pipe, a hopper (not shown) is provided, for example, via a rotary valve (not shown). In the classification chamber 18, the coarse powder Pc of the raw material powder, after being classified, passes through the communication portion 44 and gap 39, and is recovered by the hopper via the coarse powder recovery chamber 28 and the coarse powder recovery pipe. The aforementioned gap 39 constitutes the coarse powder discharge port 60. The coarse powder discharge port 60 discharges the coarse powder Pc and the fine powder Pf generated from the separation of the raw material powder Ps in the classification chamber 18.

[0081] The coarse powder recovery section is composed of a coarse powder recovery chamber 28. Figure 1 In the configuration of the coarse powder recovery section shown, fine powder Pf is discharged from the upper disc-shaped part 14 (one component) side, while coarse powder Pc is discharged from the classification plate 16 (the other component) side and from the gap 39 (coarse powder discharge port 60) located at the outer edge of the classification chamber 18.

[0082] Here, the coarse powder recovery section, such as the coarse powder recovery chamber 28, is provided on either the upper disc-shaped portion 14 (one component) or the classification plate 16 (the other component) that sandwiches the classification chamber 18 and faces the upper disc-shaped portion 14 (one component). It is connected to the outer edge of the classification chamber 18 and discharges the coarse powder Pc, which has been classified within the classification chamber 18, to the outside of the classification chamber 18. The configuration of the coarse powder recovery section is not limited to... Figure 1 The structure shown is as described.

[0083] On the annular wall 19 of the housing 12, on the side of the micro-powder recovery pipe 30 in the direction H, a plurality of first air nozzles 34 are provided. Furthermore, on the annular wall 19, below the first air nozzles 34 in the direction H, a suction nozzle 36 is provided. That is, a plurality of suction nozzles 36 are provided.

[0084] Furthermore, a second air nozzle 38 is provided on the cylindrical housing 12 below the suction nozzle 36 in the direction H. That is, a plurality of second air nozzles 38 are provided.

[0085] like Figure 4 As shown, a plurality of first air nozzles 34 are provided along the outer edge 18c of the classification chamber 18, each having a predetermined angle relative to the tangential direction of the outer edge 18c of the classification chamber 18, and are arranged at equal intervals in the circumferential direction of the classification chamber 18, for example, six nozzles are provided. When there is a plurality of first air nozzles 34, preferably, they are arranged at predetermined angles relative to the tangential direction of the outer edge 18c of the classification chamber 18, and at equal intervals in the circumferential direction of the classification chamber 18.

[0086] The suction nozzles 36 draw in gas in the tangential direction of the rotating flow within the classification chamber 18. A plurality of suction nozzles 36 are arranged along the outer edge 18c of the classification chamber 18, each having a predetermined angle relative to the tangential direction of the outer edge 18c, and are arranged at equal intervals in the circumferential direction of the classification chamber 18, for example, six nozzles. When there are a plurality of suction nozzles 36, preferably, they are arranged at predetermined angles relative to the tangential direction of the outer edge 18c of the classification chamber 18, and at equal intervals in the circumferential direction of the classification chamber 18.

[0087] like Figure 4 As shown, the number of first air nozzles 34 is the same as the number of suction nozzles 36, but it is not limited to this. As mentioned above, at least one suction nozzle 36 is sufficient. The number of first air nozzles 34 and the number of suction nozzles 36 may also be different.

[0088] likeFigure 4 As shown, when viewed from above, i.e., from above, the suction nozzle 36 is configured to face the first air nozzle 34.

[0089] Although not shown, the second air nozzle 38 is also arranged in the same manner as the first air nozzle 34, along the outer edge 18c of the grading chamber 18, in a plurality of such a number, each having a predetermined angle relative to the tangential direction of the outer edge 18c of the grading chamber 18, and arranged at equal intervals in the circumferential direction of the grading chamber 18, for example, six such nozzles are arranged.

[0090] The first air nozzle 34 and the second air nozzle 38 are respectively connected to a pressurized gas supply unit (not shown) and have gas injection ports. By supplying gas at a predetermined pressure from the pressurized gas supply unit to the first air nozzle 34 and ejecting (jetting) pressurized gas from each nozzle, a rotating flow that rotates in the same direction is formed in the classification chamber 18. Furthermore, the gas is appropriately determined according to the raw material powder being classified or the purpose of classification, but air can be used, for example. In the case where the raw material powder reacts with air, other non-reactive gases can be appropriately used. A blower is used, for example, in the pressurized gas supply unit.

[0091] Furthermore, pressurized gas is supplied from the pressurized gas supply section to the second air nozzle 38, and pressurized gas is ejected (jetted) from the second air nozzle 38 to supply pressurized gas to the gap 39 between the outer end 16a of the grading plate 16 and the housing 12.

[0092] The number of the first air nozzle 34 and the second air nozzle 38 is not limited to the number mentioned above. It may be one or more, depending on the configuration of the device.

[0093] Furthermore, the first air nozzle 34 is not limited to a nozzle, but may also be a guide vane or the like, as described later, depending on the configuration of the device.

[0094] The suction nozzle 36 of the gas suction unit is connected to the suction unit (not shown) and has a suction port. The suction nozzle 36 draws gas from the classification chamber 18 from the suction port, for example, in the tangential direction of the rotating flow. A suction blower is used in the suction unit, for example.

[0095] On the surface 12a of the housing 12, in the direction W, the supply pipe 42 is provided at predetermined intervals relative to the micro powder recovery pipe 30. The supply pipe 42 is provided at the outer edge of the housing 12. For example, a raw material supply section 40 for supplying raw material powder Ps to the classification chamber 18 is provided in the upper part of the supply pipe 42. The supply pipe 42 is, for example, a hollow frustum-shaped pipe. The supply pipe 42 is configured such that the front end of the frustum with a smaller diameter faces the surface 12a of the housing 12. A pipe 43 with a fixed diameter is connected to the front end of the frustum with a smaller diameter. The connection between the supply pipe 42 and the housing 12 is formed by the pipe 43 with a fixed diameter. The supply pipe 42 is connected to the upper disc-shaped part 14, for example, via the pipe 43 and the piping 56, and the raw material powder Ps is supplied to the classification chamber 18 through the opening 42a of the upper disc-shaped part 14.

[0096] An injector section 54 is provided in the supply pipe 42 of the raw material supply section 40. The supply pipe 42 and the injector section 54 are connected by a pipe 43. The injector section 54 has: an ejection nozzle 55 for ejecting raw material powder Ps into the classification chamber 18; and a pressure section 57 for supplying air to the ejection nozzle 55 at high pressure, for example. For example, the ejection nozzle 55 is connected to the upper disc-shaped section 14 via a pipe 56. The raw material powder Ps in the raw material supply section 40 is supplied to the classification chamber 18 through the opening 42a of the upper disc-shaped section 14 by the high-pressure air supplied from the pressure section 57 via the ejection nozzle 55 and the pipe 56.

[0097] By having an ejector section 54, the raw material powder Ps can be reliably supplied to the rotating flow generated in the classification chamber 18. In addition, the ejection nozzle 55 and pressure section 57 of the ejector section 54 can be appropriately utilized with known techniques used in powder handling.

[0098] Next, the operation of the air classifier 10 will be explained.

[0099] First, by drawing air from the classification chamber 18 through the micro powder recovery pipe 30 via a blower (not shown) at a predetermined airflow, and supplying pressurized gas from the pressurized gas supply unit (not shown) to the first air nozzle 34, a rotating flow (not shown) is generated in the classification chamber 18.

[0100] Furthermore, through the suction section (not shown), the gas in the classification chamber 18 is drawn from the suction port of the suction nozzle 36, for example, in the tangential direction of the rotating flow.

[0101] In this state, high-pressure air is supplied from the pressure section 57 via the ejection nozzle 55 and the piping 56, so that the raw material powder Ps in the raw material supply section 40 passes through the opening 42a of the upper disc-shaped section 14 and is supplied to the rotating flow of the classification chamber 18 in a predetermined amount, which has a particle size distribution.

[0102] The rotating flow is also formed in the classification chamber 18 due to the pressurized gas ejected from the first air nozzle 34. Therefore, the raw material powder Ps supplied to the classification chamber 18 from the raw material ejection nozzle (not shown) rotates within the classification chamber 18, and is subjected to centrifugal separation due to centrifugal force. As a result, the velocity of the powder flowing from outside the device to the micro-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.

[0103] Furthermore, since the gas inside the classification chamber 18 is drawn from its outer edge 18c, for example, tangentially in the rotating flow, coarse powder in the smaller particle size powder is removed. Thus, it is possible to classify the powder into fine powder and coarse powder at even smaller particle sizes. Therefore, the larger coarse powder Pc does not flow into the fine powder recovery pipe 30 through the fine powder discharge port 14a, but remains inside the classification chamber 18; on the other hand, fine powder Pf with a size below the classification point is drawn out of the fine powder recovery pipe 30 along with the airflow through the fine powder discharge port 14a. In this way, fine powder Pf can be classified and recovered from the raw material powder Ps with a particle size distribution, thereby enabling the recovered fine powder Pf to have an even smaller particle size than before.

[0104] Furthermore, the remaining portion of the raw material powder that is not discharged from the fine powder recovery pipe 30, namely the coarse powder Pc, falls from the classification chamber 18 to the coarse powder recovery chamber 28 through the gap 39 via the communication 44 between the classification plate 16 and the annular wall 19. Then, the remaining portion of the raw material powder, namely the coarse powder Pc, is recovered via the coarse powder recovery pipe (not shown).

[0105] Compared to air nozzles, guide vanes can perform classification with high precision depending on conditions such as airflow. Therefore, the guide vane method can be selected according to the classification objective, as described below.

[0106] In the airflow classifier 10, the outer periphery of the generally disc-shaped classification chamber 18 is enclosed by an annular wall 19. Therefore, even if a large flow of pressurized gas is forcibly introduced from the first air nozzle 34, air will not leak out of the classification chamber 18 in the circumferential direction, and the vortex will not become turbulent. Therefore, in particular, by increasing the inflow rate of pressurized gas from the first air nozzle 34, which is used to form a rotating flow in the coarse powder recovery chamber 28, submicron particles can be stably classified.

[0107] Fine particles, like submicron particles, tend to agglomerate easily. However, according to the air classifier 10, classification can be performed efficiently by ejecting a large flow of pressurized gas from the first air nozzle 34. 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 classification targets.

[0108] However, depending on the purpose of the classification, the first air nozzle 34 can also be a guide vane with a wider range of air volume settings.

[0109] (Second example of an air classifier)

[0110] Figure 5 This is a schematic cross-sectional view illustrating a second example of an airflow classifier according to an embodiment of the present invention.

[0111] Figure 5 In the airflow classifier 10a shown, for the classifier with Figure 1 The airflow classifier 10 shown is the same component, given the same symbol, and its detailed description is omitted.

[0112] Figure 5 The air classifier 10a shown is similar to... Figure 1 Compared to the airflow classifier 10 shown, the classification chamber 18 has a different configuration; otherwise, it is different from... Figure 1 The airflow classifier 10 shown has the same configuration.

[0113] The classification chamber 18 of the airflow classifier 10a has a groove 50 in the top wall 13 (upper disc-shaped part 14). However, the classification plate 16 does not have a groove 51.

[0114] Inclined part 24b ( Figure 1 (Refer to) The first region 24a not formed in the upper disc-shaped portion 14 ( Figure 1 (Refer to) and the inclined part 26b ( Figure 1 (Refer to) The second region 26a of the grading plate 16 was not formed. Figure 1 (See reference).

[0115] In the airflow classifier 10a, the surface 14c of the upper disc-shaped portion 14 facing the classification chamber 18 is configured, for example, as a plane parallel to direction W. This direction W is orthogonal to direction H.

[0116] The surface 16c of the grading plate 16 facing the grading chamber 18 is configured, for example, as a plane parallel to the direction W. The surface 14c of the upper disc-shaped portion 14 is parallel to the surface 16c of the grading plate 16.

[0117] Air classifier 10a andFigure 1 Similarly, the airflow classifier 10 shown draws air from the classification chamber 18 at a predetermined airflow rate through a blower (not shown) via a micro-powder recovery pipe 30, and supplies pressurized gas to the first air nozzle 34 from a pressurized gas supply unit (not shown), thereby generating a rotating flow (not shown) in the classification chamber 18. The gas in the classification chamber 18 is drawn from the suction port of the suction nozzle 36 in the tangential direction (not shown) of the rotating flow via the suction unit (not shown).

[0118] In this state, the raw material powder Ps in the raw material supply section 40 is fed through the opening 42a of the upper disc-shaped section 14, thereby supplying a predetermined amount of raw material powder Ps with a particle size distribution to the rotating flow of the classification chamber 18. In this way, the fine powder Pf can be classified and recovered from the raw material powder Ps with a particle size distribution. The airflow classifier 10a can also obtain the same... Figure 1 The air classifier 10 shown has the same effect.

[0119] In addition, in the air classifier 10a, the above-mentioned Figure 1 Similarly, the air classifier 10 shown may have grooves 50 provided on the top wall 13 (upper disc-shaped portion 14) of the classification chamber 18 and grooves 51 provided on the classification plate 16. Furthermore, the air classifier 10a may also be configured to have either grooves 50 or grooves 51.

[0120] (The third example of an air classifier)

[0121] Figure 6 This is a schematic cross-sectional view showing a third example of an airflow classifier according to an embodiment of the present invention. Figure 6 In the airflow classifier 10b shown, for the classifier with Figure 1 The airflow classifier 10 shown is the same component, given the same symbol, and its detailed description is omitted.

[0122] Figure 6 The air classifier 10b shown is Figure 1 Compared to the airflow classifier 10 shown, the differences lie in the fact that a guide vane 62 is provided instead of the first air nozzle 34, and the arrangement of the suction nozzle 36. Other than these, the configuration is different. Figure 1 The airflow classifier 10 shown has the same configuration.

[0123] exist Figure 1 The air classifier 10 shown is Figure 5 In the configuration of the airflow classifier 10a shown, guide vanes 62 can also be provided. Figure 6 (Refer to) instead of the first air nozzle 34.

[0124] In this case, with Figure 1 The first air nozzle 34 in the airflow classifier 10 shown is the same, and a plurality of guide vanes 62 are provided along the outer edge 18c of the classification chamber 18. Furthermore, the guide vanes 62 are positioned in the annular wall 19, below the suction nozzle 36 in the direction H. The guide vanes 62 are identical to the first air nozzle 34. Figure 1 (Referring to the previous section) Similarly, each guide vane has a predetermined angle relative to the tangential direction of the outer edge 18c of the classification chamber 18, and is arranged at equal intervals in the circumferential direction of the classification chamber 18. The gas supply section has a plurality of guide vanes 62.

[0125] A pressure chamber 64 is provided on the outer periphery of a plurality of guide vanes 62, which stores air and supplies gas into the classification chamber 18. The pressure chamber 64 is connected to a pressurized gas supply unit (not shown). Gas at a predetermined pressure is supplied from the pressurized gas supply unit through the pressure chamber 64 between the plurality of guide vanes 62. By supplying pressurized gas to the guide vanes 62, a rotating flow is generated in the classification chamber 18.

[0126] In the air classifier 10b, the raw material powder Ps is centrifugally separated while rotating and moving downward inside the classification chamber 18. The guide vanes 62 function to adjust the rotational speed of the raw material powder Ps during centrifugal separation. Each guide vane 62 is rotatably supported on the annular wall 19 via a rotating shaft (not shown), and is engaged with a rotating plate (not shown) by a pin (not shown). For example, it can be configured such that by rotating the rotating plate, all guide vanes 62 rotate simultaneously by a predetermined angle. By rotating the rotating plate and rotating all guide vanes 62 by a predetermined angle, the spacing between each guide vane 62 can be adjusted, thereby changing the flow rate of gas, such as air, through the spacing between the guide vanes 62. This allows for changes in classification performance, such as the classification point. Furthermore, by providing guide vanes 62, the range of selectable classification points can be expanded.

[0127] Air classifier 10b and Figure 1 Similarly, the airflow classifier 10 shown draws air from the classification chamber 18 at a predetermined airflow rate via a suction blower (not shown) and a fine powder recovery pipe 30. Then, gas at a predetermined pressure is supplied from a pressurized gas supply unit (not shown) through a pressure chamber 64 between a plurality of guide vanes 62, thereby generating a rotating flow in the classification chamber 18. The gas in the classification chamber 18 is drawn from the suction port of the suction nozzle 36 in the tangential direction of the rotating flow via a suction unit (not shown).

[0128] In this state, the raw material powder Ps in the raw material supply section 40 is supplied to the rotating flow of the classification chamber 18 through the opening 42a of the upper disc-shaped section 14, thereby supplying a predetermined amount of raw material powder Ps with a particle size distribution. In this way, the fine powder Pf can be classified and recovered from the raw material powder Ps with a particle size distribution. The same process can also be achieved in the air classifier 10b. Figure 1 The air classifier 10 shown has the same effect.

[0129] exist Figure 6 In the configuration of the airflow classifier 10b shown, as follows: Figure 5 As shown, the top wall 13 (the surface 14c of the upper disc-shaped part 14) is flat, and the surface 16c of the grading plate 16 is also flat. Alternatively, the surface 14c of the upper disc-shaped part 14 and the surface 16c of the grading plate 16 can be parallel.

[0130] exist Figure 6 In the configuration of the airflow classifier 10b shown, the top wall 13 (the surface 14c of the upper disc-shaped portion 14) is made flat, and the surface 16c of the classifying plate 16 facing the classifying chamber 18 can be other inclined portions instead of the inclined portion 26b. The inclined portion is an inclined surface formed by the flat surface, and the cross-sectional shape is a straight line. In this case, the inclined portion is inclined from the annular wall 19 towards the micro powder discharge outlet 16b, that is, it is inclined from the outside of the classifying chamber 18 towards the center, so as to reduce the height of the classifying chamber 18. That is, the surface 16c of the classifying plate 16 descends from the second cylindrical portion 22 towards the outer end portion 16a. In this case, the inclined portion, i.e., the inclined surface, is also provided with a groove 51.

[0131] When the angle between the inclined portion of the grading plate 16 and the line parallel to the direction W of the upper disc-shaped portion 14 is set to β, the angle β is preferably 5° to 30°, and more preferably 10° to 20°.

[0132] Alternatively, the inclined portion 26b may not be provided on the surface 16c of the grading plate 16. Figure 1 (Refer to), and an inclined portion 24b is provided on the surface 14c of the upper disc-shaped portion 14 (refer to), Figure 1 Reference).

[0133] In addition, although Figure 1 The air classifier 10 shown Figure 5 The air classifier 10a shown is Figure 6 The airflow classifier 10b shown is configured to remove fine powder Pf from the upper disc-shaped section 14, but the removal of fine powder Pf is not particularly limited. For example, it could also be configured to remove fine powder Pf from the classifying plate 16.

[0134] exist Figure 1 The air classifier 10 shown is Figure 5In the configuration of the airflow classifier 10a shown, the suction nozzle 36 is positioned below the first air nozzle 34 in the direction H, but this is not a limitation. The positions of the first air nozzle 34 and the suction nozzle 36 may be interchanged, with the first air nozzle 34 positioned below the suction nozzle 36 in the direction H.

[0135] exist Figure 1 The air classifier 10 shown Figure 5 The air classifier 10a shown is Figure 6 In the configuration of the airflow classifier 10b shown, the diameter D1 of the first cylindrical section 20 and the diameter D2 of the second cylindrical section 22 can be the same, or the diameter D1 of the first cylindrical section 20 can be larger than the diameter D2 of the second cylindrical section 22. The diameter D2 of the second cylindrical section 22 can also be larger than the diameter D1 of the first cylindrical section 20.

[0136] Figure 1 The air classifier 10 shown Figure 5 The air classifier 10a shown is Figure 6 The airflow classifier 10b shown has an ejector section 54 installed in the supply pipe 42 of the raw material supply section 40, but it is not limited to this and may also be configured without the ejector section 54.

[0137] Furthermore, in Figure 1 The air classifier 10 shown Figure 5 The air classifier 10a shown is Figure 6 The airflow classifier 10b shown is configured to generate a rotating flow by supplying raw material powder Ps into the classification chamber 18, but it is not limited to this configuration. For example, it could also be configured to generate a rotating flow by supplying raw material powder Ps from the classification plate 16 into the classification chamber 18.

[0138] In any of the aforementioned airflow classifiers 10, 10a, and 10b, the gas suction unit draws gas into the classification chamber 18 in the tangential direction of the rotating flow via the suction nozzle 36. In this case, for example, gas is ejected (jetted) from the first air nozzle 34 and the second air nozzle 38. This corresponds to configuration 1 in Table 1 below. However, as shown in configuration 1 in Table 1 below, although gas is drawn into the classification chamber 18 in the tangential direction of the rotating flow via the suction nozzle 36 (configuration 1 in Table 1 below), it is not limited to this.

[0139] For example, instead of the suction nozzle 36, gas can be drawn from the outer edge 18c of the classification chamber 18 and from the second air nozzle 38. In this case, the second air nozzle 38 is a suction nozzle. Gas located between the outer end 16a of the classification plate 16 and the annular wall 19 of the housing 12, and communicating with the classification chamber 18 through the communication portion 44, is drawn by the second air nozzle 38, while gas in the classification chamber 18 is drawn from the outer edge 18c of the classification chamber 18. At this time, for example, the configuration becomes that gas is ejected (jetted) from the first air nozzle 34 and the suction nozzle 36. This corresponds to configuration 2 in Table 1 below.

[0140] Furthermore, for example, instead of the suction nozzle 36, gas can also be drawn from the outer edge 18c of the classification chamber 18 from the first air nozzle 34, for example, gas can be drawn in the tangential direction of the rotating flow within the classification chamber 18. In this case, the first air nozzle 34 becomes a suction nozzle, for example, gas is drawn in the tangential direction of the rotating flow within the classification chamber 18. At this time, for example, it becomes a configuration where gas is ejected (jetted) from the suction nozzle 36 and the second air nozzle 38. This corresponds to configuration 3 in Table 1 below.

[0141] Furthermore, for example, in addition to the suction nozzle 36, gas can also be drawn from the second air nozzle 38, from the outer edge 18c of the classification chamber 18, for example, within the classification chamber 18, in the tangential direction of the rotating flow. In this case, the second air nozzle 38 acts as another gas suction unit. As described above, gas is drawn from the second air nozzle 38 through the gap 39 communicating with the classification chamber 18 via the connecting portion 44, while gas within the classification chamber 18 is drawn from the outer edge 18c of the classification chamber 18. At this time, for example, it becomes a configuration where gas is ejected (jetted) from the first air nozzle 34. This corresponds to configuration 4 in Table 1 below.

[0142] Furthermore, for example, instead of the suction nozzle 36, gas in the classification chamber 18 can be drawn from the outer edge 18c of the classification chamber 18 via the first air nozzle 34. Additionally, gas in the classification chamber 18 can also be drawn from the outer edge 18c of the classification chamber 18 via the second air nozzle 38. In this case, gas is ejected (jetted) from the suction nozzle 36. This corresponds to configuration 5 in Table 1 below. In this case, the second air nozzle 38 corresponds to other gas suction units.

[0143] As described above, when the first air nozzle 34 is configured as a suction nozzle 36, similarly to the suction nozzle 36, it is preferable to have more than one first air nozzle 34 to attract gas in the tangential direction of the rotating flow within the classification chamber 18, while the first air nozzle 34 functioning as a suction nozzle 36 may also be a single nozzle. When multiple first air nozzles 34 functioning as suction nozzles 36 are present, they are preferably arranged at equal intervals in the circumferential direction of the classification chamber 18.

[0144] Furthermore, as described above, when the second air nozzle 38 is configured as a suction nozzle 36, similarly to the suction nozzle 36, it is preferable to have more than one second air nozzle 38, while the second air nozzle 38 that functions as a suction nozzle 36 may also be a single one. In the case of having a plurality of second air nozzles 38 that function as suction nozzles 36, they are preferably arranged at equal intervals in the circumferential direction of the grading chamber 18.

[0145] Table 1

[0146] Configuration 1 Configuration 2 Configuration 3 Configuration 4 Configuration 5 First air nozzle Injection Injection Suction Injection Suction Suction nozzle Suction Injection Injection Suction Injection Second air nozzle Injection Suction Injection Suction Suction

[0147] The present invention is essentially constructed as described above. The airflow classifier of the present invention has been described in detail above, but 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.

[0148] [Example]

[0149] The classification performed by the airflow classifier of the present invention will now be described in more detail.

[0150] Using the above Figure 1 The air classifier 10 shown, and the air classifier used for comparison, classify raw material powders. The air classifier used for comparison and... Figure 1 Compared to the airflow classifier 10 shown, it does not have the structure of suction nozzle 36.

[0151] The airflow classifier 10 of the present invention performs classification by setting the classification conditions, such as airflow volume, to the same conditions as a comparative airflow classifier. Figure 1In the airflow classifier 10 shown, case 1 (configuration 1 in Table 1) describes the following configuration: gas is ejected from the first air nozzle 34, the suction nozzle 36, and the second air nozzle 38, and gas is drawn from the suction nozzle 36 from the outer edge 18c of the classification chamber 18 in the tangential direction of the rotating flow within the classification chamber 18. Case 2 (configuration 2 in Table 1) describes the following configuration: gas is ejected from the first air nozzle 34 and the suction nozzle 36, and gas is drawn from the second air nozzle 38 from the outer edge 18c of the classification chamber 18 in the tangential direction of the rotating flow within the classification chamber 18.

[0152] The raw material powder uses metal particles with a diameter of 198 nm. Furthermore, the particle size is the diameter converted from BET specific surface area.

[0153] In Case 1 of the air classifier 10, the microparticle size is 98 nm. In Case 2 of the air classifier 10, the microparticle size is 95 nm. The microparticle size of the air classifier used for comparison is 127 nm.

[0154] Using the above Figure 5 The air classifier 10a shown, and the air classifier used for comparison, classify raw material powders. The air classifier used for comparison and... Figure 5 Compared to the airflow classifier 10a shown, it does not have the structure of suction nozzle 36.

[0155] The airflow classifier 10a of the present invention performs classification by setting the classification conditions such as air volume to the same conditions as the airflow classifier used for comparison.

[0156] The raw material powder uses silica particles with an average particle size of 0.6 μm. Furthermore, the average particle size is determined by laser diffraction and scattering methods.

[0157] exist Figure 7 The chart shows the results of the grading. Figure 7 In the text, the symbol 70 represents... Figure 5 The diagram shows the classification results of an airflow classifier 10a, while symbol 72 indicates the classification results of an airflow classifier used for comparison. For example... Figure 7 As shown, the present invention achieves high grading accuracy and enables the grading points to be smaller. In other words, the present invention can miniaturize the grading points.

Claims

1. An airflow classifier, characterized in that, have: The housing has a top wall and an annular wall continuously disposed on the outer edge of the top wall; A grading plate is configured with its surface facing 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 into the grading chamber to generate a rotating flow; A gas suction unit draws the gas from the outer edge of the classification chamber into the classification chamber; The raw material supply unit supplies the raw material powder to the rotating flow generated in the classification chamber; The micro powder outlet is located at the center of one of the top wall of the shell constituting the classification chamber and the surface of the classification plate; as well as The coarse powder outlet opens along the outer periphery of the classification chamber on either side of the top wall and the surface of the classification plate opposite to the top wall.

2. The airflow classifier as described in claim 1, characterized in that, It also includes: other gas suction parts, between the outer end of the grading plate and the annular wall of the housing, to attract gas from the gap communicating with the grading chamber.

3. An airflow classifier, characterized in that, have: The housing has a top wall and an annular wall continuously disposed on the outer edge of the top wall; A grading plate is configured with its surface facing 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 into the grading chamber to generate a rotating flow; A gas suction unit, located between the outer end of the grading plate and the annular wall of the housing, draws in gas from the gap communicating with the grading chamber. The raw material supply unit supplies the raw material powder to the rotating flow generated in the classification chamber; The micro powder outlet is located at the center of one of the top wall of the shell constituting the classification chamber and the surface of the classification plate; as well as The coarse powder outlet opens along the outer periphery of the classification chamber on either side of the top wall and the surface of the classification plate opposite to the top wall.

4. The airflow classifier as described in any one of claims 1 to 3, characterized in that, The gas supply unit has a plurality of air nozzles that supply the gas into the classification chamber to generate the rotating flow. The air nozzles are arranged at equal intervals along the outer edge of the classification chamber in the circumferential direction of the classification chamber.

5. The airflow classifier as described in any one of claims 1 to 3, characterized in that, The gas suction unit has one or more suction nozzles that attract gas in the tangential direction of the rotating flow within the grading chamber.

6. The airflow classifier as described in claim 5, characterized in that, The gas suction unit has a plurality of suction nozzles that attract gas in the tangential direction of the rotating flow within the classification chamber, and are arranged at equal intervals in the circumferential direction of the classification chamber.

7. The airflow classifier as described in any one of claims 1 to 3, characterized in that, It also has: A groove is disposed on at least one of the surfaces of the top wall and the grading plate; and At least one of a first cylindrical portion and a second cylindrical portion, wherein the first cylindrical portion is disposed at the micro powder outlet, and the second cylindrical portion is opposite to the first cylindrical portion and disposed on the surface of the classification plate in the classification chamber with a predetermined gap.

8. The airflow classifier as described in claim 7, 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; the groove is provided on the inclined surface.

9. The airflow classifier as described in claim 8, characterized in that, The inclined plane slopes from the outside of the grading chamber toward the center, with the height of the grading chamber gradually increasing.

10. The airflow classifier as described in any one of claims 1 to 3, characterized in that, Among the surfaces of the top wall and the grading plate, a groove is provided on the side with the micro powder outlet, the groove being concentric with the micro powder outlet along the periphery of the micro powder outlet; a concentric groove is provided on the side without the micro powder outlet, the groove being opposite to the concentric groove provided in the area surrounding the micro powder outlet. The concentric circular grooves located on the side with the micro powder outlet and the concentric circular grooves located on the side without the micro powder outlet are positioned in the same direction orthogonal to the direction opposite to the top wall of the housing of the classification chamber and the surface of the classification plate.

11. The airflow classifier as described in any one of claims 1 to 3, characterized in that, The raw material supply unit is connected to either the top wall of the shell constituting the classification chamber or the surface of the classification plate, thereby supplying the raw material powder to the rotating flow generated within the classification chamber.

12. The airflow classifier as described in claim 11, characterized in that, The raw material supply section has an ejector nozzle that supplies the raw material powder to the rotating flow generated in the classification chamber.

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