POWDER PROCESSING DEVICE

Abstract

 To achieve lower air flow rate and finer powder with a simple constitution, a powder processing device is provided with: a cylindrical housing; a raw material supply unit; a first rotating body that rotates around a center axis; a pulverizing member for pulverizing the raw material; a second rotating body that rotates around the center axis; a plurality of blades that are disposed in the second rotating body; an air inflow unit that is disposed at the lower side of the rotating body and allows inflow of an air flow to the inside of the housing; an air outflow unit for discharging the air flow, including powder, from the top of the housing; and a guide surface of which the front side is positioned more to the inside in the radial direction than the back side in the direction of rotation of the second rotating body.

Description

Technical Field

[0001] The present invention relates to a powder processing apparatus for pulverizing a material in the form of lumps to produce powdery or granular particles.

Background Art

[0002] A conventional fine-pulverizing apparatus is disclosed in Japanese Patent Application Publication No. 2001-259451. This fine-pulverizing apparatus includes: a pulverizing rotor which is disposed rotatably inside a pulverization chamber; a liner which is disposed around an outer circumferential part of the pulverizing rotor with a gap in between; a classifying rotor which discharges out particles of a predetermined particle size or smaller; a circulation passage which guides downward the part of the material that remains undischarged by the classifying rotor; and vanes which protrude inward from the inner face of the pulverization chamber so that the part of the material that remains undischarged by the classifying rotor collides the vanes so as to be hindered from swirling along the inner face of the pulverization chamber.

[0003] In this fine-pulverizing apparatus, the material fed to it is pulverized by the pulverizing rotor and the liner. The pulverized material then moves upward with an air flow introduced inside, and is given a centrifugal force by the classifying rotor. The part of the material with particle sizes smaller than the predetermined particle size with which the inward force due to the air flow is stronger than the centrifugal force is discharged out. The part of the material that remains undischarged, that is, the part with particle sizes larger than the predetermined particle size, tending to flow in the circumferential direction along the pulverization chamber, collides with the vanes, and falls to be pulverized once again by the pulverizing rotor and the liner. Thus, providing the vanes prevents a large amount of material from falling at once onto the pulverizing rotor, preventing pulsation of the pulverizing rotor and allowing stable driving of the pulverizing rotor.

Citation List

Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2001-259451.

Summary of Invention

Technical Problem

[0005] Inconveniently, however, in the fine-pulverizing apparatus of Japanese Patent Application Publication No. 2001-259451, also the air flow produced by the classifying rotor collides with the vanes. Having collided with the vanes, the air flow passes in the upward and downward directions. The downward air flow collides with the air flow that passes through the gap between the pulverizing rotor and the liner toward the classifying rotor, and this reduces the flow speed, and hence the energy, of the air flow passing toward the classifying rotor. Thus, in the fine-pulverizing apparatus of Japanese Patent Application Publication No. 2001-259451, the air flow passing toward the classifying rotor needs to be given a sufficient flow rate for it to pass upward even while being blown onto by the air flow that has collided with the vanes. The particle size of the powdery or granular particles classified by the classifying rotor is inversely proportional to the rotation speed of the classifying rotor and is proportional to the square root of the flow rate of the air flow passing toward the classifying rotor. In Japanese Patent Application Publication No. 2001-259451, it is difficult to reduce the flow rate of the air flow passing toward the classifying rotor, and thus it is difficult to reduce to below a certain particle size the particle size of the powdery or granular particles that is classified.

[0006] Devised to solve the inconveniences mentioned above, the present invention is aimed at providing a powder processing apparatus that, in spite of a simple structure, operates with a low flow-rate air flow and produces a fine-pulverized powdery or granular particles.

Solution to Problem

[0007] To achieve the above object, according to one aspect of the present invention, a powder processing apparatus includes: a tubular casing extending in the plumb-vertical direction; a material feeder configured to feed a material into the casing; a first rotary body disposed below the material feeder and rotatable about the center axis extending in the plumb-vertical direction; a pulverizing member disposed in an outer peripheral part of the first rotary body in the radial direction and configured to pulverize the material into powdery or granular particles; a swirling air flow generator disposed above the first rotary body inside the casing and configured to produce an air flow in the swirling direction inside the casing; an air flow inlet disposed below the rotary bodies in the casing and configured to let an air flow into the casing; and an air flow outlet configured to let the air flow out through an upper part of the casing. Inside the casing, there is provided a guide having a guide face. The guide face faces the swirling air flow generator in the radial direction. The front side of the guide face in the rotating direction of the swirling air flow generator is located inward, in the radial direction, of the rear side of the guide face in the rotating direction of the swirling air flow generator.

[0008] With this structure, the guide face gives a force acting inward in the radial direction to the powdery or granular particles swirling inside the casing. Thus, even with a reduced flow rate of the air flow passing in through the air flow inlet, the powdery or granular particles can be given a force that pushes them inward. This helps reduce the flow rate of the air flow passing in through the air flow inlet. Reducing the flow rate of the air flow helps reduce the particle diameter of the powdery or granular particles discharged through the air flow outlet. That is, fine-pulverized powdery or granular particles can be produced. Moreover, reducing the flow rate of the air flow helps reduce the size of the apparatus that produces the air flow, and helps reduce the size of the entire apparatus. Furthermore, reducing the flow rate of the air flow helps reduce power consumption and achieve power saving.

[0009] In the above structure, the swirling air flow generator can include: a second rotary body rotatable about the center axis; and a plurality of blades disposed upright radially in a circumferential part of the second rotary body. With this structure, powdery or granular particles can be classified with a simple structure.

[0010] In the above structure, a face resulting from imaginarily extending, in the circumferential direction, the guide face from a front-end part of it in the rotating direction can be located outward, in the radial direction, of the swirling air flow generator. With this structure, the air flow guided by the guide face is less likely to hinder the centrifugal force that the swirling air flow generator gives the powdery or granular particles. Powdery or granular particles can also be prevented from colliding with the swirling air flow generator.

[0011] In the above structure, the casing can include a tubular housing tube extending along the center axis, and at least one of the guide can extend inward in the radial direction from the housing tube. With this structure, the guide can be fixed securely.

[0012] In the above structure, a housing top plate expanding in the direction perpendicular to the center axis can be provided in an upper-end part of the casing, and at least one of the guide can extend downward from the bottom face of the housing top plate. With this structure, the guide can be fixed securely. Also, the guide can be dismounted along with the housing top plate, and this allows easy maintenance.

[0013] In the above structure, the guide can be plate-shaped.

[0014] In the above structure, the guide face can be a curved face of which a middle part in the circumferential direction is convex in the radial direction

[0015] In the above structure, the top side of the guide face can be located frontward, in the rotating direction of the swirling air flow generator, of the bottom side of the guide face.

Advantageous Effects of Invention

[0016] According to the present invention, it is possible to provide a powder processing apparatus that, in spite of a simple structure, operates with a low flow-rate air flow and produces a fine-pulverized powdery or granular particles.

Brief Description of Drawings

[0017] 

Fig. 1 is a sectional view of a powder processing apparatus according to the present invention;

Fig. 2 is a plan view of a pulverizer;

Fig. 3 is a sectional view of the pulverizer shown in Fig. 2 along line III-III;

Fig. 4 is a plan view of a swirling air flow generator and a guide;

Fig. 5 is a sectional view showing another manner of fitting guide plates;

Fig. 6 is a plan view showing another example of a guide used in a powder processing apparatus according to the present invention;

Fig. 7 is a plan view showing yet another example of a guide;

Fig. 8 a schematic arrangement diagram of one example of a powder processing system according to the present invention;

Fig. 9 is a sectional view of a conventional powder processing apparatus used in tests of a comparative example;

Fig. 10 is a graph showing the results of Test 1;

Fig. 11 is a graph showing the results of Test 2;

Fig. 12 is a graph showing the length of time required after a material stops being supplied until a pulverizer returns to an idle-rotation state;

Fig. 13 is a graph showing pulverization efficiency;

Fig. 14 is a graph showing the content of fine powder in powdery or granular particles produced; and

Fig. 15 is a graph showing pulverization efficiency.

Description of Embodiments

[0018] A powder processing apparatus according to the present invention will be described below with reference to the accompanying drawings.

< 1. Structure of Powder Processing Apparatus >

[0019] Fig. 1 is a sectional view of a powder processing apparatus according to the present invention. The powder processing apparatus A pulverizes (crushes) a material in the form of lumps into powdery or granular particles. As shown in Fig. 1, the powder processing apparatus A includes a casing 10, a material feeder 20, a driver 30, a pulverizer 40, a swirling air flow generator 50, a guide 60, and an air flow outlet 70. The direction along which the center axis C1 runs will be referred to as the up-down direction. The direction perpendicular to the up-down direction will be referred to as the radial direction, toward the center being inward and away from the center being outward. The direction along the circumference about the center axis C1 will be referred to as the circumferential direction.

<1.1 Structure of Casing 10>

[0020] The casing 10 includes a housing 11, a shaft holder 12, a material inlet 13, an air flow inlet 14, a bottom cover 15, and a hinge 16. The housing 11 is in a cylindrical shape, extending along the center axis C1 running in the up-down direction.

<1.1.1 Structure of Housing 11>

[0021] As shown in Fig. 1, the housing 11 includes a housing bottom 111, a housing tube 112, a flange 113, and a housing top plate 114. The housing bottom 111 is disc-shaped, expanding in the radial direction outward from the center. The housing 11 is fixed to an unillustrated base or the like such that the housing bottom 111 lies horizontal. The housing tube 112 is in a cylindrical shape, extending from an outer edge part of the housing 11 upward along the center axis C1. The housing tube 112 is in a cylindrical shape about the center axis C1.

[0022] The flange 113 is disposed at the upper end of the housing tube 112, and expands outward in the radial direction. The flange 113 and the housing tube 112 are formed unitarily. That is, the housing bottom 111, the housing tube 112, and the flange 113 constitute a unitarily formed metal body. The metal can be, but is not limited to, for example, stainless steel.

[0023] As shown in Fig. 1, a lower-end part of the housing tube 112 is closed by the housing bottom 111. An upper-end part of the housing tube 112 is open. The housing top plate 114 closes the opening in the upper-end part of the housing cylinder 112. The housing top plate 114 is fitted to the flange 113 via the hinge 16. Thus, the housing top plate 114 pivots about an axle 161 of the hinge 16 to open and close the opening of the housing tube 112.

[0024] With the opening of the housing tube 112 closed, the housing top plate 114 is fixed to the flange 113 with a screw or the like. Thus, the housing tube 112 and the housing top plate 114 are securely fixed together and are hermetically sealed so that no air flow leaks through a gap. The fixing with a screw or the like can be done at one place or, for secure fixing and sealing, can be done preferably at a plurality of places. A gasket, packing, or the like can be disposed for increased airtightness.

[0025] In a central part of the housing bottom 111, a through hole 115 that penetrates it in the up-down direction is formed. A first shaft 31 and a second shaft 32, which will be described later, of the driver 30 are disposed through the through hole 115. In a central part of the housing top plate 114, an discharge hole 116 that penetrates it in the up-down direction is provided.

< 1.1.2 Structure of Shaft Holder 12 >

[0026] As shown in Fig. 1, the shaft holder 12 is disposed in a central part of the housing bottom 111 and is in a tubular shape, extending in the up-down direction. The shaft holder 12 has its center aligned with the center axis C1. The shaft holder 12 is fixed to the housing bottom 111 with a fixing member such as a screw.

[0027] In an upper-end part of the shaft holder 12, a seal (here, a labyrinth seal) is formed. This prevents an air flow containing powdery or granular particles from passing into the shaft holder 12, without hampering the rotation of the first rotary body 41.

< 1.1.3 Structure of Material Inlet 13 >

[0028] Through the material inlet 13, a material in the form of lumps that is supplied from the material feeder 20 is fed into the housing tube 112, that is, into the casing 10. As shown in Fig. 1, the material inlet 13 is a through hole formed in the housing tube 112 and penetrating it in the radial direction. The material inlet 13 is disposed above the pulverizer 40 disposed inside the housing tube 112.

< 1.1.4 Structure of Air Flow Inlet 14 >

[0029] Through the air flow inlet 14, an air flow that passes from outside the housing tube 112 into it is supplied. As shown in Fig. 1, the air flow inlet 14 is a through hole provided in the housing tube 112 and penetrating it in the radial direction. The air flow inlet 14 is disposed below the pulverizer 40.

< 1.1.5 Structure of Bottom Cover 15 >

[0030] The bottom cover 15 is disposed inside the housing tube 112, below the pulverizer 40. The bottom cover 15 is in the shape of a circular ring. The bottom cover 15 and a first rotary body 41 face each other in the up-down direction with an interval left in between. An air flow passes into the gap between the top face of the bottom cover 15 and the bottom face of the first rotary body 41 of the pulverizer 40. With this air flow, the powdery or granular particles pulverized by the pulverizer 40 is conveyed upward and inward. Accordingly, the air flow supplied through the air flow inlet 14 will be referred to as the conveying air flow.

<1.2 Structure of Material Feeder 20>

[0031] As shown in Fig. 1, the material feeder 20 includes a material feed pipe 21 and a screw conveyor 22. The material feed pipe 21 is a pipe-form body; part of the material feed pipe 21 is inserted through the material inlet 13 into the housing tube 112 and is thereby fixed. Inside the material feed pipe 21, the screw conveyor 22 is disposed rotatably. The screw conveyor 22, as it rotates, moves a material in the form of lumps along the material feed pipe 21. The material in the form of lumps moved by the screw conveyor 22 is fed into the housing tube 112 through the material inlet 13. Any conveying method other than one that uses a screw conveyer can instead be used.

<1.3 Structure of Driver 30>

[0032] The driver 30 drives the pulverizer 40 and the swirling air flow generator 50. As shown in Fig. 1, the driver 30 includes a first shaft 31, a second shaft 32, a first belt 331, and a second belt 332.

< 1.3.1 Structure of First Shaft 31 >

[0033] The first shaft 31 is in a tubular shape. To the upper end of the first shaft 31, the first rotary body 41 is fixed. The first shaft 31 is supported rotatably via an unillustrated bearing disposed inside the shaft holder 12. The first shaft 31 is supported in the up-down direction with respect to the shaft holder 12 so as to be rotatable about the center axis C1.

[0034] A lower-end part of the first shaft 31 is disposed through the through hole 115 in the housing bottom 111 and protrudes downward beyond the housing bottom 111. To the lower-end part of the first shaft 31, a first pulley 311 is fixed so as not to rotate relative to it. The method of fixing the first pulley 311 can be, but is not limited to, for example, press-fitting, welding, or application of adhesive. For reliable prevention of rotation, a key and a key way can be used. The first shaft 31 can be given a sectional shape other than circular to prevent rotation.

[0035] The first pulley 311 is wound with the first belt 331. A rotative force is transmitted from an unillustrated motor via the first belt 331 to the first pulley 311, which thus rotates about the center axis C1. As a result, the first shaft 31, to which the first pulley 311 is fitted, and the first rotary body 41, which is fixed to the first shaft 31, rotate about the center axis C1.

< 1.3.2 Structure of Second Shaft 32 >

[0036] The second shaft 32 is in a circular columnar shape, and is disposed inside the first shaft 31, which is in a tubular shape. The second shaft 32 is supported rotatably on the first shaft 31 via an unillustrated bearing. That is, the second shaft 32 is supported on the shaft holder 12 rotatably about the center axis C1.

[0037] A lower-end part of the second shaft 32 protrudes downward beyond the lower-end part of the first shaft 31. To the part of the second shaft 32 that protrudes downward beyond the lower-end part of the first shaft 31, a second pulley 321 is fixed so as not to rotate relative to it. The method of fixing the second pulley 321 can be, but is not limited to, for example, press-fitting, welding, or application of adhesive. For reliable prevention of rotation, a key and a key way can be used. The second shaft 32 can be given a sectional shape other than circular to prevent rotation.

[0038] The second pulley 321 is wound with the second belt 332. A rotative force is transmitted from an unillustrated motor via the second belt 332 to the second pulley 321, which thus rotates about the center axis C1. As a result, the second shaft 32, to which the second pulley 321 is fitted, and a second rotary body 51, which is fixed to the second shaft 32, rotate about the center axis C1.

[0039] To allow the first and second pulleys 311 and 321 to rotate at different rotation speeds, they can be fed with driving forces from separate motors. Instead, a speed reducer can be used so that, with a common motor, the first and second pulleys 311 and 321 are made to rotate at different rotation speeds. Here, different rotation speeds may be in the same direction or in opposite directions.

< 1.4. Structure of Pulverizer 40 >

[0040] The pulverizer 40 is disposed below the material feeder 20. The pulverizer 40 pulverizes the material in the form of lumps fed from the material feeder 20 into powdery or granular particles. The pulverizer 40 will now be described in detail with reference to new drawings. Fig. 2 is a plan view of the pulverizer. Fig. 3 is a sectional view of the pulverizer shown in Fig. 2 along line III-III. As shown in Figs. 1 to 3, the pulverizer 40 is disposed inside the housing tube 112, and includes a first rotary body 41, hammers 42, and a liner 43.

< 1.4.1 Structure of First Rotary Body 41 >

[0041] As shown in Fig. 2, the first rotary body 41 is in a circular shape as seen from the up-down direction. That is, the first rotary body 41 is disc-shaped. At the center of the first rotary body 41, a shaft fixing bore 411 is provided. To the shaft fixing bore 411, the first shaft 31 is fixed so as not to rotate relative to it. The fixing of the first shaft 31 to the shaft fixing bore 411 can be achieved by, for example, press-fitting. Any of a variety of other fixing methods can instead be used, examples including screw-fastening, welding and application of adhesive. For reliable prevention of rotation, a key and a key way can be used. The first shaft 31 can be given a sectional shape other than circular to prevent rotation.

[0042] As shown in Figs. 2 and 3, at the outer edge of the top face of the first rotary body 41, a plurality of (here, 12) hammer seats 412 are provided. As shown in Fig. 3, the hammer seat 412 is a recess that is recessed downward from the top face of the first rotary body 41. The hammer seats 412 are disposed at equal intervals in the circumferential direction. The hammer seat 412 extends inward from the outer edge of the first rotary body 41. The hammer seat 412 has an inward part of it formed in the shape of a circular arc.

< 1.4.2. Structure of Hammer 42 >

[0043] The hammers 42 are one example of a pulverizing member. The hammer 42 includes a hammer base 421, a prop 422, and a pulverizing blade 423. The hammer base 421 is in the shape of a flat plate, and is inserted in a hammer seat 412. The hammer base 421 is fixed to the first rotary body 41 with a screw 40a (see Figs. 2 and 3). The method of fixing can instead be, for example, welding or application of adhesive.

[0044] The prop 422 is formed unitarily with the hammer base 421 to protrude, to one side, from one end of it. As shown in Fig. 3, when the hammer base 421 is inserted in the hammer seat 412, the prop 422 is upright. The pulverizing blade 423 is disposed outside the prop 422 in the radial direction. The pulverizing blade 423 has a plurality of bumps and dents (protuberances and recessions) extending in the up-down direction. The bumps and dents can extend parallel to the center axis C1, or can be inclined in the circumferential direction relative to the center axis C1.

< 1.4.3 Structure of Liner 43 >

[0045] As shown in Fig. 3, the liner 43 is ring-shaped. The inner face of the liner 43 faces the outer faces of the hammers 42 with an interval in between. The liner 43 comprises a plurality of liner chips 431. The liner chips 431 are arrayed in contact with each other in the circumferential direction along the inner circumferential face of the housing tube 112. Thus, the inner circumferential face of the liner 43 facing the hammers 42 is formed in the shape of a polygonal ring. The liner chips 431 can be fixed to the housing tube 112, for example, with screws. The liner chip 431 has, on its inward facing face, a pulverizing blade 432, which have bumps and dents formed on them. The pulverizing blade 432 can instead comprise, like the pulverizing blade 423 on the hammer 42, bumps and dents (protuberances and recessions) extending in the up-down direction. The pulverizing blades 432 can have dented grooves formed in an intersecting pattern with bumps formed in a polygonal shape such as a square or right triangular shape. Instead, pin-form bumps can be arrayed two-dimensionally.

[0046] As the first rotary body 41 rotates, the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner chips 431 move relative to each other in the circumferential direction. When the first rotary body 41 is rotating at high speed, the pulverizing blades 423 and 432 pulverize a material in the form of lumps. Accordingly, at least the pulverizing blade 423 on the hammer 42 and at least the pulverizing blade 432 on the liner chip 431 need to be formed of a high-strength, high-hardness, and highly wear-resistant material such as ceramic (for example, alumina or zirconia), tungsten carbide, cemented carbide, or tool steel. The entire hammer 42 can be formed of one of those materials. Here, a highly wear-resistant material is mentioned merely as an example, and is not meant as any limitation.

[0047] The face of the liner chip 431 on which the pulverizing blade 432 is formed is a flat face. This, as compared with a structure where the pulverizing blade 432 is formed on a curved face, makes it easy to manufacture the liner chips 431. Moreover, by changing the number of liner chips 431, it is possible to change the inner diameter of the liner 43 within a certain range. This makes it possible to use common liner chips 431 in liners 43 of different sizes. Furthermore, the liner chips 431 with a simple shape are easy to manufacture out of a material, such as ceramic, that is difficult to form into a complicate shape. This helps reduce the manufacturing cost of the powder processing apparatus A. A structure is also possible where pulverizing blades 432 are formed on the inner face of a liner 43 in the shape of a circular ring.

[0048] Though omitted in this embodiment, a top plate can be fitted on the top face of the first rotary body 41. The top plate is provided to reduce the risk of the first rotary body 41, the hammers 42, the screws 40a, and the like being destroyed or worn out as a result of collision with the material fed in through the material inlet 13. The top plate can be formed of a highly wear-resistant material.

<1.5 Structure of Swirling Air Flow Generator 50>

[0049] The swirling air flow generator 50 is disposed above the pulverizer 40 inside the casing 10. That is, above the swirling air flow generator 50, the discharge hole 116 is disposed. The swirling air flow generator 50, as it rotates, produces a swirling air flow inside the casing 10. By producing the swirling air flow, the swirling air flow generator 50 gives a centrifugal force to the powdery or granular particles. The swirling air flow generator 50 will now be described in detail with reference to new diagrams. Fig. 4 is a plan view of a swirling air flow generator and a guide. As shown in Figs. 1 and 4, the swirling air flow generator 50 includes a second rotary body 51 and a plurality of blades 52.

< 1.5.1 Structure of Second Rotary Body 51 >

[0050] As shown in Fig. 4, the second rotary body 51 has a circular shape as seen in a plan view. That is, the second rotary body 51 is disc-shaped. To the second rotary body 51, a second shaft 32 is fixed so as not to rotate relative to it. The second rotary body 51 and the second shaft 32 have their centers aligned with the center axis C1. The fixing of the second shaft 32 can be achieved by being press-fitted in an unillustrated through bore, or by, for example, screw-fastening, welding, or application of adhesive. For reliable prevention of rotation, a key and a key way can be used. Thus, as the second shaft 32 rotates, the second rotary body 51, and hence the swirling air flow generator 50, rotates about the center axis C1.

<1.5.2 Structure of Blades 52>

[0051] On the top face of the second rotary body 51, a plurality of blades 52 that extend radially are fixed at equal intervals in the circumferential direction. The plurality of blades can be inserted in grooves formed in the top face of the second rotary body 51 and then be fixed by welding or application of adhesive. The blade 52 fixed on the top face of the second rotary body 51 extends outward at the top side. That is, of the region where the blade 52 passes, the part where an outer-end part of an upper-end part of the blade 52 passes is the outermost part.

[0052] The blade 52 has a face perpendicular to the rotating direction of the swirling air flow generator 50. As the swirling air flow generator 50 rotates, an air flow that passes in the circumferential direction is produced. As shown in Fig. 4, the swirling air flow generator 50 rotates in the counter-clockwise direction Rd as seen in a plan view. As the swirling air flow generator 50 rotates, inside the casing 10, that is, inside the housing tube 112, an air flow that swirls in the counter-clockwise direction Rd along the housing tube 112 is produced. Moreover, as will be described in detail later, powdery or granular particles are separated according to its particle size (hereinafter referred to as "classified") by the swirling air flow produced by the swirling air flow generator 50.

<1.6 Structure of Guide 60>

[0053] As shown in Figs. 1 and 4, the guide 60 includes guide plates 61 and support ribs 62, all disposed inside the housing tube 112. The guide plates 61 are one example of a guide member.

< 1.6.1 Structure of Guide Plates 61 >

[0054] As shown in Fig. 4, inside the housing tube 112, a plurality of (here, six) guide plates 61 are disposed at equal intervals in the circumferential direction. The guide plate 61 is a rectangular plate, and extends in the up-down direction. The guide plate 61 has a guide face 611, which faces the swirling air flow generator 50 in the radial direction. As shown in Fig. 1, a lower-end part of the guide face 611 extends up to the same or approximately the same position as a lower-end part of the blade 52.

[0055] As shown in Fig. 4, the guide plate 61 is fixed to the inner face of the housing tube 112 such that, with respect to the rotating direction of the swirling air flow generator 50, and hence of the second rotary body 51, the front side of the guide face 611 is located inward of its rear side. Examples of the method of fixing the guide plates 61 include, for example, welding and application of adhesive. This, however, is not meant as any limitation: a structure can be used where they are fixed by being inserted in grooves provided on the housing tube 112. Any of a variety of fixing methods that allow secure fixing of the guide plates 61 can be used.

[0056] As shown in Fig. 4, a face 612 resulting from imaginarily extending, along the circumferential direction from a front-end part of the guide face 611 in the rotating direction of the swirling air flow generator 50 is located outside the region where the blades 52 of the swirling air flow generator 50 pass. The guide face 611 guides the air flow produced by the swirling air flow generator 50 inward so that the air flow will not blow directly onto the swirling air flow generator 50. Thus, the powdery or granular particles that swirl with the swirling air flow are guided inward while being restrained from colliding the blades 52.

< 1.6.2 Structure of Support Ribs 62 >

[0057] As shown in Figs. 1 and 4, the support rib 62 is plate-shaped, and is fixed to the face of the guide plate 61 opposite from the guide face 611 and to the inner face of the housing tube 112. The support rib 62 keeps the guide plate 61 fixed. Providing the support rib 62 helps restrain the guide plate 61 from giving when being blown onto by the air flow.

[0058] In the embodiment, one support rib 62 is provided at the middle of the guide plate 61 in the up-down direction. Instead, a plurality of support ribs 62 can be provided. Instead, a support rib 62 that supports the entire guide plate 61 can be provided.

< 1.6.3 Other Examples of Guide >

[0059] Other examples of the guide 60 will be described. Fig. 5 is a sectional view showing another way of fitting guide plates. As shown in Fig. 5, guide plates 61 can be fixed to the bottom face of the housing top plate 114. In Fig. 5, the guide plates 61 are fixed to the housing top plate 114 by screw-fastening. Instead of by screw-fastening, the fixing can be achieved by, for example, welding or deposition. As shown in Fig. 5, a guide plate 61a that is fixed by being fitted directly to the bottom face of the housing top plate 114 can be used, or a guide plate 61b that is fixed by being inserted in a groove that is formed on the bottom face of the housing top plate 114 so as to be recessed upward can be used. With those structures, simply removing the housing top plate 114 permits the guide plates (61a, 61b) to be dismounted, and this allows easy maintenance of the guide plates (61a, 61b). In structures where guide plates are fitted to the housing top plate 114, it is preferable that the guide plates be so shaped as not to hinder the opening and closing of the housing top plate 114. The housing top plate 114 can be fitted to the flange 113 with no hinge in between.

[0060] Fig. 6 is a plan view showing another example of the guide used in a powder processing apparatus according to the present invention. As shown in Fig. 6, curved guide plates 63 can be used. Such a guide plate 63 has a curved guide face 631. The guide plate 63 is so disposed that a face resulting from imaginarily extending, along the circumferential direction from a front-end part of the guide plate 63 in the rotating direction of the second rotary body 51 is located outside the region where the blades 52 of the swirling air flow generator 50 pass. Providing curved guide faces 631 permits smooth guiding of the swirling air flow. The guide face 631 is convex outward. This, however, is not meant as any limitation: a curved face that is convex inward can be used. Depending on the flow speed of the swirling air flow, the viscosity of the air flow, and the like, any of a variety of shapes that do not tend to produce eddies can be used.

[0061] Guide members 64, 65, and 66 as shown in Fig. 7 can be used. Fig. 7 is a plan view of yet another example of the guide. As shown in Fig. 7, as the guide member 64, not a guide plate in the shape of a flat plate but a guide member 64 that projects in the radial direction can be used. Here, a face resulting from imaginarily extending from a front-end part of the guide face 641 of the guide member 64 in the rotating direction of the second rotary body 51 is located outside the region where the blades 52 of the swirling air flow generator 50 pass. Like the guide member 65, the guide face 651 can be made longer. Like the guide member 66, the guide face 661 can be a curved face. The guide members 64, 65, and 66 can be formed unitarily with the housing 11. Instead, guide members 64, 65, and 66 fabricated as separate members can be fixed to the inside of the housing 11. Faces 642, 652, and 662 resulting from imaginarily extending from front-end parts of the guide faces 641, 651, and 661_in the rotating direction of the second rotary body 51 are located outside the region where the blades 52 of the swirling air flow generator 50 pass.

[0062] The guide faces 611, 631, 641, 651, and 661 described above are each configured as a face that extends in the up-down direction, that is, a face of which the entirety from the upper end to the lower end occupies the same position in the circumferential direction. This, however, is not meant as any limitation: instead, for example, the top side of a guide face can be located frontward of the lower side of it in the rotating direction of the first rotary body 41. This allows smooth guiding of the swirling air flow inward.

<1.7 Structure of Air Flow Outlet 70>

[0063] Through the air flow outlet 70, the air flow (air) that has passed in through the air flow inlet 14 is discharged. As shown in Fig. 1, the air flow outlet 70 is fitted to the top face of the housing top plate 114. The air flow outlet 70 includes an exhaust pipe 71 and an exhaust flange 72. The exhaust pipe 71 is in a cylindrical shape, and communicates with a discharge opening 116. The air inside the housing 11 flows through the discharge opening 116 into the exhaust pipe 71.

[0064] The exhaust flange 72 can be disposed on the top face of the housing top plate 114 with an unillustrated gasket in between. The exhaust flange 72 is fixed to the housing top plate 114, for example, with screws. This increases the airtightness between the housing top plate 114 and the exhaust pipe 71, and restrains leakage of the air flow. Instead of the gasket, an O-ring or the like can be used. Instead, a depression can be formed on one of the air flow outlet 70 and the housing top plate 114 and an elevation on the other so that the elevation can be inserted in the depression to achieve airtightness.

<2. Operation of Powder Processing Apparatus >

[0065] A powder processing apparatus A according to the present invention is structured as described above. Next, a powder processing system that employs the powder processing apparatus A will be described, and the operation of the powder processing apparatus included in the powder processing system will be described. Fig. 8 is a schematic arrangement diagram of one example of a powder processing system according to the present invention. The powder processing system CL shown in Fig. 8 includes a material feeding apparatus Ma, a powder processing apparatus A, a filtering apparatus Ft, and a blower Bw.

[0066] The powder processing apparatus A is fixed to a horizontal face on a base Ca with unillustrated screws or otherwise. The air flow outlet 70 of the powder processing apparatus A is connected to an inlet Ft3 of the filtering apparatus Ft via piping. The filtering apparatus Ft is, for example, a bag filter. The filtering apparatus Ft includes a housing Ft1, a partition Ft2, an inlet Ft3, an outlet Ft4, a filter element Ft5, and a dispensing port Ft6. In the filtering apparatus Ft, the partition Ft2 divides the inside of the housing Ft1 into an upper part and a lower part. The partition Ft2 has a plurality of through holes formed in it. Inside the housing Ft1, below the partition Ft2, there are disposed tubular filter elements Ft5, which fit around the circumferences of the through holes and which extend downward.

[0067] The air flow from the powder processing apparatus A passes through the inlet Ft3 into the housing Ft1, then passes through the filter element Ft5, and then passes through the outlet Ft4 to the outside. Meanwhile, powdery or granular particles are collected on the outer face of the filter element Ft5. Into the filtering apparatus Ft, compressed gas (compressed air) is periodically introduced from an unillustrated pipe to blow down the powdery or granular particles collected on the filter element Ft5.

[0068] At the lower end of the housing Ft1, the dispensing port Ft6 is provided. Through the dispensing port Ft6, the powdery or granular particles that have deposited in a lower part of the filter element Ft5 are taken out. In the powder processing system CL, the powdery or granular particles taken out through the dispensing port Ft6 are the powdery or granular particles that have undergone classification, that is, the product.

[0069] The outlet Ft4 of the filtering apparatus Ft is connected to the blower Bw via piping. The blower Bw produces a negative pressure in the piping connected to the outlet Ft4. The negative pressure produces an air flow passing toward the blower Bw in the filtering apparatus Ft, the powder processing apparatus A, and the piping that connect these together. In the powder processing apparatus A, the negative pressure causes an air flow to pass in through the air flow inlet 14. A separate blower (unillustrated) can be provided outside the air flow inlet 14 so that an air flow produced by it is made to pass in forcibly.

[0070] The operation of the powder processing apparatus A will now be described. In the powder processing apparatus A, while the first and second rotary bodies 41 and 51 are rotating, a material in the form of lumps is supplied from the material feeder 20. The material supplied from the material feeder 20 falls onto the first rotary body 41 in the pulverizer 40. The material is pulverized into powdery or granular particles by the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner 43.

[0071] As mentioned previously, in the powder processing apparatus A, air (an air flow) passes through the air flow inlet 14 into the housing 11. The air flow that has passed in through the air flow inlet 14 passes outward in the radial direction through the gap between the first rotary body 41 and the bottom cover 15, and the passes upward between the first rotary body 41 and the liner 43 along the housing tube 112. The destination toward which the air flow passes is the air flow outlet 70. Accordingly, the air flow that passes out from between the first rotary body 41 and the liner 43 passes upward and inward simultaneously. Moreover, while passing between the first rotary body 41 and the liner 43, the air flow moves together with the pulverized powdery or granular particles. That is, the powdery or granular particles pulverized in the pulverizer 40 are conveyed upward and inward by a conveying air flow.

[0072] In the upper part of the housing 11, a swirling air flow is produced by the swirling air flow generator 50. The conveying air flow that has passed in through the air flow inlet 14 joins the swirling air flow. Here, the powdery or granular particles contained in the conveying air flow is acted upon by two forces, namely an inward force F1 ascribable to the conveying air flow and an outward force F2 ascribable to the swirling air flow. The force F1 varies with the flow rate (flow speed) of the conveying air flow such that, the faster the conveying air flow, the stronger the force F1. The force F2 varies with the flow rate (flow speed) of the swirling air flow, that is, the rotation speed of the swirling air flow generator 50, such that the higher the rotation speed of the swirling air flow generator 50, the stronger the force F2.

[0073] The above discussion leads to the conclusion: of the powdery or granular particles conveyed by the conveying air flow, that part which are conveyed together with the air flow discharged through the air flow outlet 70 have particle diameters that depend on the flow rate of the conveying air flow and the rotation speed of the swirling air flow generator 50. More specifically, the powdery or granular particles discharged through the air flow outlet 70 has a median diameter D₅₀ that is proportional to the square root of the flow rate of the conveying air flow and that is inversely proportional to the rotation speed of the swirling air flow generator 50. In the powder processing apparatus A, it is possible, by controlling the flow rate of the conveying air flow and the rotation speed of the swirling air flow generator 50, to adjust to a prescribed particle diameter the particle diameter of the powdery or granular particles discharged through the air flow outlet 70, that is, the classified powdery or granular particles. A median diameter D₅₀ here denotes the particle diameter at which, when powdery or granular particles are lined up in order of particle diameter, the number of powdery or granular particles smaller than that particle diameter and the number of powdery or granular particles larger than that particle diameter are equal.

[0074] The part of the powdery or granular particles that remain undischarged through the air flow outlet 70 after classification have particle diameters larger than the prescribed particle diameter. Those powdery or granular particles are pushed outward by the swirling air flow, make contact with the inner face of the housing tube 112, and then move downward along the inner face of the housing tube 112. They are then pulverized again by the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner 43, and are then conveyed again upward by the conveying air flow.

[0075] In this way, through repetition of pulverizing by the hammers 42 and the liner 43, conveying by the conveying air flow, and classifying by the swirling air flow, a material is pulverized into powdery or granular particles with a prescribed particle diameter or smaller. The powdery or granular particles so produced are collected by the filtering apparatus Ft to be taken out.

[0076] In a powder processing apparatus A according to the present invention, inside a housing 11, guide plates 61 are disposed. The guide faces 611 of the guide plates 61 guide a swirling air flow inward. This action directs the swirling air flow inward. This permits the force F1 ascribable to the swirling air flow to be weaker than in a case where no guide plates 61 are disposed. This helps reduce the flow rate of a conveying air flow and the rotation speed of a swirling air flow generator 50 required to obtain a predetermined particle diameter. In other words, it is possible to keep the flow rate of the conveying air flow low, and thus to produce fine-pulverized powdery or granular particles. It is also possible, by reducing the flow rate of the conveying air flow and the rotation speed of the swirling air flow generator 50, to reduce power consumption, that is, to save energy.

[0077] The guide faces 611 are so disposed as to direct the swirling air flow inward smoothly. Thus, as compared with a conventional structure where the swirling air flow is collided with a plate-shaped member, powdery or granular particles are less likely to settle on the guide plates 61, and the swirling air flow is less likely to develop eddies. This makes it possible to produce powdery or granular particles smoothly and efficiently.

[0078] High-temperature, low-humidity air, that is, hot dry air, can be introduced through the air flow inlet 14 to remove the moisture contained in the powdery or granular particles pulverized by the hammers 42 and the liner 43. This gives a configuration as what is called an air flow drying apparatus.

<2.1 Other Examples of Powder Processing Apparatus>

[0079] In the powder processing apparatus, the particle diameter of the powdery or granular particles that move inward can be controlled by use of the swirling air flow produced by the swirling air flow generator 50 and the air flow conveyed by the conveying air flow. This can be exploited to produce powdery or granular particles with a uniform particle diameter and with fewer pointed parts, that is, closer to spheres (to achieve what is called spheroidization) through repeated grinding between the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner 43 performed while discharging powdery or granular particles with particle diameters smaller than a given value. An unillustrated dispensing port can be provided in the housing tube 112 of the powder processing apparatus A so that, through the dispensing port, rounded powdery or granular particles can be taken out.

[0080] As described above, in the powder processing apparatus A, the swirling air flow is directed inward by the guide faces 611. Thus, even when the flow rate of the conveying air flow is low, powdery or granular particles can be conveyed inward; even when the flow rate of the conveying air flow is low, powdery or granular particles are less likely to stay inside the housing 11. This helps prevent overpulverization, that is, pulverization going to far as a result of repeated pulverization between the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner 43, and thus helps restrain production of excessively fine particles.

<3. Evaluation of Powder Processing Apparatus>

[0081] The performance of a powder processing apparatus A according to the present invention was evaluated. As a comparative example, a conventional powder processing apparatus P was used. Fig. 9 is a sectional view of the conventional powder processing apparatus used in the testing of the comparative example.

[0082] The powder processing apparatus P shown in Fig. 9 has substantially the same structure as the powder processing apparatus A shown in Fig. 1 except that it includes, instead of the guide plates 61, a cylinder 81 and vertical vanes 82. Accordingly, with respect to the powder processing apparatus P, those parts which find substantially the same parts in the powder processing apparatus A are identified by the same reference signs, and no detailed description of those parts will be repeated. In Fig. 9, the reference signs of those parts that are not directly relevant to the features of the present invention are omitted.

[0083] As shown in Fig. 9, the powder processing apparatus P has the cylinder 81 inside the housing tube 112. The cylinder 81 is in a tubular shape, enclosing the outside of the swirling air flow generator 50. The vertical vanes 82 are flat plates, and connect the outer face of the cylinder 81 with the inner face of the housing tube 112. A plurality of (for example, six) vertical vanes 82 are provided, and are disposed along the radial direction.

[0084] In the powder processing apparatus P, the powdery or granular particles conveyed by the swirling air flow flows in the circumferential direction along the housing tube 112, and collide with the vertical vanes 82. Then, they fall down. The powdery or granular particles that have fallen down are pulverized by the pulverizer 40 again. The powder processing apparatus P of the comparative example is structured as described above.

[0085] The operation of the powder processing apparatus P will be described. In the powder processing apparatus P, as in the powder processing apparatus A, a material that is supplied from the material feeder 20 falls onto the first rotary body 41. The material is pulverized into powdery or granular particles by the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner 43. The pulverized material is conveyed by the conveying air flow, and passes between the inner circumference of the housing tube 112 and the outer circumference of the cylinder 81. Subsequently, powdery or granular particles are classified by the swirling air flow generator 50. Thus, powdery or granular particles with particle diameters smaller than a prescribed particle diameter pass through the gaps between the blades 52, and are discharged out through the discharge opening 116. On the other hand, powdery or granular particles with particle diameters larger than the prescribed particle diameter move downward inside the cylinder 81, and fall onto the first rotary body 41. The powdery or granular particles that have fallen are pulverized again into finer powdery or granular particles, that is, powdery or granular particles with smaller particle diameters, by the pulverizing blades 423 on the hammers 42 and the pulverizing blades 432 on the liner 43. In the powder processing apparatus P, through repetition of the operation described, the material is pulverized and is also classified.

<3.1 Test Conditions>

[0086] In the following evaluation, the test results with the powder processing apparatus A according to the present invention will be mentioned as those of Practical Example, and the test results with the conventional powder processing apparatus P will be mentioned as those of Comparative Example. The outer diameter defined by the outer sides of the hammers 42 in the pulverizer 40 will be referred to the hammer outer diameter. In both Practical Example and Comparative Example, tests were conducted under the same conditions. The test conditions are as noted below. Those conditions which vary among different tests are noted in the sections describing the corresponding evaluation. In the graphs referred to in the course of the following description, square marks refer to Practical Example, and triangular marks refer to Comparative Example.

Shape of Pulverizing Blades on Hammer:	Vertical Grooves
Hammer Outer Diameter:	318.1 mm
Number of Hammers:	12
Rotation Speed of Pulverizer:	7000 rpm
Rotation Speed of Swirling Air Flow Generator:	2000-7000 rpm
Material To Be Pulverized:	Heavy Calcium Carbonate (with a particle diameter of about 1 mm)

<3.2 Evaluation 1 >

[0087] In Evaluation 1, the powder processing apparatus A and the powder processing apparatus P were operated under the conditions noted above, and were subjected to Tests 1 and 2 with different flow rates of the conveying air flow on each powder processing apparatus. The flow rates of the conveying air flow in the respective tests were as noted below.

Test 1

Flow Rate of Conveying Air Flow:

Standard Flow Rate

Test 2

Flow Rate of Conveying Air Flow:

1/3 of Standard Flow Rate

[0088] The standard flow rate is the flow rate of the air flow supplied to the powder processing apparatus P, that is, the flow rate of the conveying air flow, in conventional powder processing performed on the powder processing apparatus P. The results of Tests 1 and 2 are shown in Figs. 10 and 11. Fig. 10 is a graph showing the results of Test 1. Fig. 11 is a graph showing the results of Test 2. In the graphs shown in Figs. 10 and 11, the vertical axis represents pulverization efficiency (kg/kW·h) and the horizontal axis represents median diameter (D₅₀ µm). Pulverization efficiency indicates the throughput of processing material per unit electric power.

[0089] As shown in Fig. 10, with a high flow rate (standard flow rate) of the conveying air flow, Practical Example and Comparative Example show almost no difference. On the other hand, as shown in Fig. 11, with a low flow rate (one third of the standard flow rate) of the conveying air flow, Practical Example shows higher pulverization efficiency than the Comparative Example. It is thus seen that, with a low flow rate of the conveying air flow, the powder processing apparatus A according to the present invention offers higher pulverization efficiency than the conventional powder processing apparatus P.

<3.3 Evaluation 2>

[0090] Next, with the flow rate of the conveying air flow set at 1 / 3.75 of the standard flow rate on both Practical Example and Comparative Example, the length of time required after the material stops being supplied until a no-load state is reached, that is, a return to idle rotation is made, was compared. The results are shown in Fig. 12. Fig. 12 is a graph showing the length of time required after the material stops being supplied until the pulverizer returns to an idle-rotation state.

[0091] In the graph in Fig. 12, the vertical axis represents the length of time required after the material stops being supplied until the load on the pulverizer 40 becomes minimal, that is, it returns to the idle-rotation state. The horizontal axis represents the median diameter (Dso) of the powdery or granular particles produced. The length of time for which powdery or granular particles stay inside the housing 11 is the length of time required by their processing.

[0092] As shown in Fig. 12, the length of time after the stop of supply of the material until the return to the idle-rotation state is, for any given median diameter D₅₀, shorter on Practical Example than on Comparative Example. It is thus seen that, with a low flow rate of the conveying air flow, the powder processing apparatus A requires a shorter processing time than the powder processing apparatus P to produce powdery or granular particles with a prescribed particle diameter. That is, it is seen that, with a low flow rate of the conveying air flow, the powder processing apparatus A according to the present invention requires a shorter processing cycle time than the conventional powder processing apparatus P.

<3.4 Evaluation 3>

[0093] Next, the material was switched from heavy calcium carbonate to scaly graphite (with a median diameter D₅₀ of 85 µm). Moreover, as the pulverizing blades 432 on the liner 43, a rectangular-groove liner with intersecting grooves and rectangular bumps was used. The rotation speed of the pulverizer 40 was 6800 rpm in both Practical Example and Comparative Example, and the rotation speed of the swirling air flow generator 50 was 3000 rpm and 7000 rpm in both Practical Example and Comparative Example. The flow rate of the conveying air flow was one third of the standard flow rate in both Practical Example and Comparative Example. The test results are shown in Fig. 13. Fig. 13 is a graph showing pulverization efficiency. In the graph in Fig. 13, the vertical axis represents pulverization efficiency and the horizontal axis represents median diameter D₅₀.

[0094] It is seen that, also with the material switched from heavy calcium carbonate to scaly graphite, with a low flow rate of the conveying air flow, the powder processing apparatus A according to the present invention offers higher pulverization efficiency than the conventional powder processing apparatus P.

< 3.5 Evaluation 4 >

[0095] In Evaluation 4, tests were conducted using polystyrene as the material. With a difficult-to-break material such as polystyrene, with a low flow rate of the conveying air flow, the powder processing apparatus P exhibited large variation in the pulverizing load and was unable to operate stably. It is thus seen that the powder processing apparatus A according to the present invention operates more stably at a low air flow rate than the conventional powder processing apparatus P. That is, it is seen that the powder processing apparatus A according to the present invention can operate at lower flow rates than the conventional powder processing apparatus P.

<3.6 Evaluation 5>

[0096] Next, in Evaluation 5, tests were conducted using flake powdery paint (5 mm square, with a thickness of 1 mm) as the material. The content (fine particle percentage) of fine particles (with particle diameters smaller than 9.25 µm) in the powdery or granular particles discharged through the air flow outlet 70 was acquired in percentage by volume. The test conditions were the same as in Test 2 in Evaluation 1. The results are shown in Fig. 14. Fig. 14 is a graph showing the content of fine particles in the powdery or granular particles produced. In Fig. 14, the vertical axis represents fine particle percentage and the horizontal axis represents median diameter D₅₀.

[0097] To produce powdery or granular particles with any given median diameter D₅₀, using the powder processing apparatus A according to the present invention results in a lower fine particle percentage than using the conventional powder processing apparatus P. That is, when producing powdery or granular particles with a prescribed particle diameter by using a given amount of material, the powder processing apparatus A according to the present invention can produce more powdery or granular particles than the conventional powder processing apparatus P. It is thus seen that the powder processing apparatus A according to the present invention produces less waste and processes powder with higher efficiency than the conventional powder processing apparatus P.

< 3, 7 Evaluation 6 >

[0098] In Evaluation 6, tests were conducted on a powder processing apparatus A1 and a powder processing apparatus PI of a different size than those used in Evaluation 1 to 5. The test conditions were as noted below.

Shape of Pulverizing Blades on Hammer:	Vertical Grooves
Hammer Outer Diameter:	430.3 mm
Number of Hammers:	32
Rotation Speed of Pulverizer:	6600 rpm
Rotation Speed of Swirling Air Flow Generator	3000-5400 rpm
Material To Be Pulverized:	Heavy Calcium Carbonate (with a particle diameter of about 1 mm)
Shape of Pulverizing Blades on Liner:	Triangular Grooves
Flow Rate of Conveying air flow:	2/3 of Standard Flow Rate

[0099] Under the conditions noted above, tests were conducted on the powder processing apparatus A1 according to the present invention and the conventional powder processing apparatus PI, and pulverization efficiency was acquired. The results are shown in Fig. 15. Fig. 15 is a graph showing pulverization efficiency. In Fig. 15, the vertical axis represents pulverization efficiency and the horizontal axis represents median diameter D₅₀.

[0100] As shown in Fig. 15, using the powder processing apparatus A1 according to the present invention results in higher pulverization efficiency than using the conventional powder processing apparatus P1. It is thus seen that, regardless of the size of the powder processing apparatus, the sizes of the housing and the pulverizer, and the number of hammers, a powder processing apparatus with guide faces according to the present invention offers higher pulverization efficiency than a conventional powder processing apparatus.

[0101] As described above, a powder processing apparatus according to the present invention has, inside a housing, a guide face that guides inward a swirling air flow produced inside the housing. Owing to this, it offers higher pulverization efficiency and requires a shorter powder processing time than a conventional powder processing apparatus. Less of the material needed to produce powdery or granular particles with a prescribed particle diameter is required on a powder processing apparatus according to the present invention than on a conventional powder processing apparatus. A powder processing apparatus A according to the present invention permits an air flow to be let in at a lower flow rate than a conventional powder processing apparatus P, that is, it operates with a lower flow-rate air flow. Accordingly, a powder processing apparatus A according to the present invention can produce finer-pulverized powdery or granular particles than a conventional powder processing apparatus P.

[0102] The above description of the present invention given by way of embodiments is not meant to limit the invention in any way. Any embodiment of the present invention can be implemented with any modifications made within the spirit of the invention.

Reference Signs List

[0103] 

10

casing

11

housing

111

housing bottom

112

housing tube

113

flange

114

housing top plate

115

through hole

116

discharge opening

12

shaft holder

13

material inlet

14

air flow inlet

15

bottom cover

20

material feeder

30

driver

31

first shaft

311

first pulley

32

second shaft

321

second pulley

331

first belt

332

second belt

40

pulverizer

41

first rotary body

412

hammer seat

42

hammer

423

pulverizing blade

43

liner

432

pulverizing blade

50

swirling air flow generator

51

second rotary body

52

blade

60

guide

61

guide plate

62

support rib

63

guide plate

64

guide member

65

guide member

66

guide member

70

air flow outlet

71

exhaust pipe

72

exhaust flange

A

powder processing apparatus

CL

powder processing system

Ft

filtering apparatus

Bw

blower

Claims

1. A powder processing apparatus comprising:

a tubular casing extending in a plumb-vertical direction;

a material feeder configured to feed a material into the casing;

a first rotary body disposed below the material feeder and rotatable about a center axis extending in the plumb-vertical direction;

a pulverizing member disposed in an outer peripheral part of the first rotary body in a radial direction and configured to pulverize the material into powdery or granular particles;

a swirling air flow generator disposed above the first rotary body inside the casing and configured to produce an air flow in a swirling direction inside the casing;

an air flow inlet disposed below the rotary bodies in the casing and configured to let an air flow into the casing; and

an air flow outlet configured to let the air flow out through an upper part of the casing,

wherein the powder processing apparatus further comprises, inside the casing, a guide having a guide face, the guide face facing the swirling air flow generator in the radial direction, a front side of the guide face in a rotating direction of the swirling air flow generator being located inward, in the radial direction, of a rear side of the guide face in the rotating direction of the swirling air flow generator.

2. The powder processing apparatus according to claim 1, wherein
the swirling air flow generator includes:

a second rotary body rotatable about the center axis; and

a plurality of blades disposed upright radially in a circumferential part of the second rotary body.

3. The powder processing apparatus according to claim 2, wherein
a face resulting from imaginarily extending, in a circumferential direction, the guide face from a front-end part thereof in a rotating direction of the second rotary body is located outward, in the radial direction, of the swirling air flow generator.

4. The powder processing apparatus according to any one of claims 1 to 3, wherein the casing includes a tubular housing tube extending along the center axis, and at least one of the guide extends inward in the radial direction from the housing tube.

5. The powder processing apparatus according to any one of claims 1 to 4, wherein a housing top plate expanding in a direction perpendicular to the center axis is provided in an upper-end part of the casing, and
at least one of the guide extends downward from a bottom face of the housing top plate.

6. The powder processing apparatus according to any one of claims 1 to 5, wherein the guide is plate-shaped.

7. The powder processing apparatus according to any one of claims 1 to 6, wherein the guide face is a curved face of which a middle part in the circumferential direction is convex in the radial direction

8. The powder processing apparatus according to any one of claims 1 to 7, wherein a top side of the guide face is located frontward, in the rotating direction of the swirling air flow generator, of a bottom side of the guide face.

9. A gas current drying apparatus comprising:

the powder processing apparatus according to any one of claims 1 to 8,

wherein hot air is let in through the air flow inlet.

10. A classifying apparatus comprising:

the powder processing apparatus according to any one of claims 1 to 8,

wherein

the powdery or granular particles are classified inside the casing, and

the classifying apparatus further comprises a collector configured to collect powdery or granular particles with outer diameters within a predetermined range contained in the air flow discharged out of the air flow outlet through the air flow outlet.

11. A particle rounding apparatus comprising:

the powder processing apparatus according to any one of claims 1 to 8,

wherein the casing includes a granule extractor for extracting spherical granules, the granule extractor being configured to extract, to outside, spherical powdery or granular particles formed inside the casing.

Drawing