JP2017006922A - Classification mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a classification mechanism having high classification accuracy.SOLUTION: A classification mechanism 10 includes: a hollow rotation shaft 40 disposed on an upper part of a classification rotor 50, and coupled to the classification rotor 50; and a raw material supply mechanism 70 for supplying raw material powder 11 to the classification rotor 50. The raw material supply mechanism 70 is configured so as to carry the raw material powder 11 toward the classification rotor 50 through an in-axis space formed in the inside of the rotation shaft 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a classification mechanism for separating raw powder into fine powder and coarse powder, and in particular, a fine particle and coarse powder are separated using a swirl flow by rotation of a classification rotor to obtain a product having a predetermined particle size range. It relates to a classification mechanism for obtaining.

  As a conventional classification mechanism, there is an airflow rotation type classification mechanism that separates fine powder and coarse powder using a swirling flow by rotation of a classification rotor. The principle of classification will be explained. In the airflow rotary classification mechanism, when the powder is put on the airflow and rotated, the large powder is moved toward the outer periphery by the centrifugal force of the swirling airflow, while the small powder goes to the center. There is a tendency for the air velocity to win and be drawn closer to the inner circumference.

  The powder discharged from the outer peripheral portion contains a lot of large powder (coarse powder), while the powder in the airflow discharged from the center portion contains a lot of small powder (fine powder). Thereby, the raw material powder in which powders of various sizes are mixed can be classified into coarse powder and fine powder.

  As such an airflow rotation type classification mechanism, an airflow discharge mechanism for discharging an airflow containing fine powder from the central portion of the classification rotor is provided on the opposite side of the rotating shaft that rotatably supports the classification rotor. It has been known. For example, a classification mechanism comprising an airflow discharge mechanism that discharges an airflow containing fine powder downward from the central portion of the classification rotor, and a raw material input port that is disposed above the classification rotor and inputs raw material powder. It is described in Patent Document 1.

JP-A-8-281213

  In general, in the classification mechanism, the lower the distribution concentration of the raw material powder in the classification rotor, the more the disturbance of the air current is suppressed, so the classification accuracy of the classification mechanism is improved. As a method for lowering the distribution density of the raw material powder, the amount of the raw material powder introduced from the raw material inlet per unit time is reduced, or the raw material powder is uniformly dispersed in the space inside the casing. I think that. For example, in Patent Document 1 described above, in order to disperse the raw material powder, a dispersion plate is provided for receiving the raw material charged from the raw material inlet and dispersing the raw material outward.

  On the other hand, in the conventional classification mechanism, the raw material inlets are arranged at one place or a plurality of places in the circumferential direction. That is, the path of the raw material powder charged into the casing is not uniform in the circumferential direction of the classification rotor. For this reason, in the conventional classification mechanism, it is difficult to disperse the raw material powder sufficiently uniformly in the circumferential direction, and therefore, the distribution concentration of the raw material powder is uneven.

  In order to uniformly disperse the raw material powder in the circumferential direction, it is also conceivable to provide a raw material input port in the vicinity of the classification air introduction port provided outside the side of the classification rotor. For example, when classification air is introduced through guide vanes (louvers), it can be considered that raw material powder is introduced so as to pass through the guide vanes and reach the vicinity of the classification rotor. However, even in this case, it is not easy to sufficiently disperse the raw material powder in the circumferential direction. Further, the velocity of the classification air is relatively low in the vicinity of the radially outer end of the guide vane ends. For this reason, it is conceivable that the raw material powder adheres to the guide blades or the raw material powder stays in the vicinity of the guide blades. As a result, the supply of the raw material powder becomes unstable.

  The present invention has been made in view of the above-described problems of the prior art, and provides a classification mechanism capable of making the distribution density of the raw material powder more uniform and thereby improving the classification accuracy. Objective.

  The present invention is a classification mechanism for classifying raw powder into fine powder and coarse powder, and is disposed on a casing, a classification rotor provided inside the casing and forming a classification space, and an upper portion of the classification rotor. A hollow rotary shaft connected to the classification rotor, and a raw material supply mechanism for supplying raw powder to the classification rotor, wherein the raw material supply mechanism is an in-shaft space formed inside the rotary shaft A classification mechanism configured to convey the raw material powder toward the classification rotor via

  In the classification mechanism according to the present invention, the raw material supply mechanism receives the raw material powder that has reached the lower end of the rotary shaft through the inner space and disperses the raw material powder radially outward of the rotary shaft. A bottom plate may be included. In this case, the bottom plate may be formed with a protruding portion that protrudes upward toward the in-axis space of the rotating shaft.

  In the classification mechanism according to the present invention, the raw material supply mechanism is disposed at a predetermined interval along a circumferential direction of the rotation shaft so as to surround the bottom plate, and a plurality of supports that connect the classification rotor to the rotation shaft. A member may be included. In this case, each support member may be configured as a guide vane that guides the raw material powder dispersed by the bottom plate outward in the radial direction of the rotation shaft.

  In the classification mechanism according to the present invention, a throttle portion for locally reducing a cross-sectional area of the space in the shaft may be formed on the rotating shaft.

  In the classification mechanism according to the present invention, the raw material supply mechanism may include an inner cylinder disposed in the inner space of the rotating shaft, and a connecting member that connects the inner cylinder to the rotating shaft. . In this case, the material which comprises the said rotating shaft, and the material which comprises the said inner cylinder may differ. In addition, the inner cylinder may be formed with a throttle portion for locally reducing the cross-sectional area of the inner space of the inner cylinder.

  The classification mechanism according to the present invention is disposed on a side of the classification rotor, and is disposed below the primary classification air introduction port, and a primary air introduction port that supplies primary classification air toward the classification rotor. And a secondary air inlet for supplying secondary classified air for blowing a part of the air upward.

  In the classification mechanism according to the present invention, the raw material supply mechanism may have a raw material input port that communicates with the space in the shaft of the rotary shaft and into which the raw material powder is input and a downward airflow is introduced. Good.

  According to the classification mechanism of the present invention, the raw material powder is conveyed toward the classification rotor through the in-axis space formed inside the rotation shaft. For this reason, the distribution density | concentration of the raw material powder in the circumferential direction can be made more uniform, and, thereby, classification accuracy can be improved.

The longitudinal cross-sectional view which shows the classification mechanism by one Embodiment of this invention. The longitudinal cross-sectional view which shows the classification mechanism by the form of a comparison. The longitudinal cross-sectional view which shows the classification mechanism by the other modification of embodiment shown in FIG. The longitudinal cross-sectional view which shows the classification mechanism by the other modification of embodiment shown in FIG. The longitudinal cross-sectional view which shows the classification mechanism by the other modification of embodiment shown in FIG. The longitudinal cross-sectional view which shows the classification mechanism by the other modification of embodiment shown in FIG. The longitudinal cross-sectional view which shows the classification mechanism by the other modification of embodiment shown in FIG.

(Classification mechanism)
Hereinafter, a classification mechanism 10 according to an embodiment of the present invention will be described with reference to FIG.

  The classification mechanism 10 according to the present embodiment is provided in the casing 20, the classification rotor 50 that forms the classification space, and the lower end of the classification mechanism 50 is connected to the classification rotor 50. And a hollow rotating shaft 40 extending in the vertical direction. The casing 20 is a main body portion 21 that encloses the classification rotor 50 from the side. The main body portion 21 has an opening formed in the upper portion thereof, covers the opening portion of the main body portion 21 from above, and the rotating shaft 40 passes therethrough. And a housing 24 disposed above the top plate 22 and surrounding the rotary shaft 40 from the side. Among these, the top plate 22 is fastened to the main body 21 by a fastener 23.

  An air introduction port 16 for supplying classified air toward the classification rotor 50 is provided on the side peripheral wall of the main body 21 of the casing 20, and a plurality of guide vanes 17 are provided inside the air introduction port 16. Has been placed. The plurality of guide vanes 17 are oriented in consideration of the flow of the swirling flow generated by the rotation of the classification rotor 50.

  A pulley 41 is attached to the rotary shaft 40, and a belt (not shown) that is driven by a drive source such as a motor that is spaced apart from the pulley 41 in the horizontal direction is wound around the pulley 41. Yes. For this reason, the rotating shaft 40 is rotationally driven around the rotating axis in the vertical direction by the driving source.

  The classification rotor 50 has an inner space formed in an annular shape, and an outer peripheral portion thereof is defined by a plurality of blades 51. The plurality of blades 51 are annularly arranged at equal intervals along the outer peripheral surface of the classification rotor 50, and have a shape and orientation suitable for forming a swirling flow. The upper surface of the classification rotor 50 is formed by a disc member 52. The lower surface of the classification rotor 50 is formed by a bottom lid 53. The disk member 52 may be provided with a bottom plate 76 to be described later on which the raw material powder 11 that has reached the lower end of the rotary shaft 40 through the space in the shaft collides. Alternatively, a part of the disk member 52 may be configured to function as a bottom plate 76 described later. That is, the disc member 52 and the bottom plate 76 may be integrated.

  The classifying mechanism 10 includes a bearing 30 that is disposed between the housing 24 of the casing 20 and the classifying rotor 50 above the classifying rotor 50 and rotatably supports the rotary shaft 40. The bearing 30 includes an inner ring 31 that contacts the rotating shaft 40, an outer ring 32 that contacts the housing 24, and a rolling element 33 that rolls between the inner ring 31 and the outer ring 32. As shown in FIG. 1, a plurality of, for example, two bearings 30 may be provided along the vertical direction. In this case, a sleeve 34 for supporting the upper bearing 30 may be provided between the two bearings 30.

  Above the upper bearing 30 and below the lower bearing 30 are upper portions for sealing gaps between rotating parts such as the classification rotor 50 and the rotating shaft 40 and non-rotating parts such as the casing 20, respectively. A seal part 25 and a lower seal part 26 may be provided. The specific structure of each of the seal portions 25 and 26 is not particularly limited. A labyrinth seal structure composed of corresponding valleys and peaks is employed. As a result, particularly with respect to the lower seal portion 26, the effect of suppressing the powder from entering the gap between the rotating component and the non-rotating component is great. Further, a seal air ejection port 28 for ejecting air may be provided in the vicinity of the lower seal portion 26. This can further suppress the powder from entering the gap. The seal air supply port 27 supplies air to the seal air ejection port 28.

  The classification mechanism 10 includes a raw material supply mechanism 70 that supplies the raw material powder 11 to be processed to the classification rotor 50. Hereinafter, the raw material supply mechanism 70 will be described.

  The raw material supply mechanism 70 is configured to convey the raw material powder 11 toward the classification rotor 50 through an in-axis space formed inside the rotary shaft 40. That is, the raw material supply mechanism 70 uses the in-axis space of the rotary shaft 40 as a path 72 for introducing the raw material powder 11 into the casing 20. For this reason, the distribution concentration of the raw material powder 11 in the circumferential direction can be made more uniform than when the raw material powder 11 is introduced into the casing 20 from one place in the circumferential direction.

  Hereinafter, a specific configuration of the raw material supply mechanism 70 will be described. As shown in FIG. 1, the raw material supply mechanism 70 is formed at the upper end of the rotary shaft 40 so as to communicate with the in-shaft space of the rotary shaft 40, the raw material inlet 71 into which the raw material powder 11 is charged, and the rotary shaft 40. The guide portion 73 is disposed between the rotary shaft 40 and the classification rotor 50 at the lower end of the rotary shaft 40 and guides the raw material powder 11 that has reached the lower end of the rotary shaft 40 through the space in the shaft and radially outward of the rotary shaft 40. And have.

  The guide part 73 includes, for example, a bottom plate 76 that receives the raw material powder 11 that has reached the lower end of the rotating shaft 40 through the space in the shaft, that is, the raw material powder 11 collides with it. The bottom plate 76 is connected to the rotary shaft 40 or the classifying rotor 50, so that the bottom plate 76 rotates together with the rotary shaft 40. Therefore, the raw material powder 11 that has collided with the bottom plate 76 is given a centrifugal force from the bottom plate 76 and dispersed outward in the radial direction of the rotating shaft 40.

  The guide portion 73 includes a plurality of support members 74 that are arranged at predetermined intervals along the circumferential direction of the rotary shaft 40 so as to surround the bottom plate 76 from the side, and connect the classification rotor 50 to the rotary shaft 40. It is out. Specifically, as shown in FIG. 1, the support member 74 has an upper end coupled to the rotary shaft 40 and a lower end connected to the classification rotor 50. The raw material powder 11 dispersed by the guide portion 73 is ejected outward from a raw material ejection port 75 formed in a gap between the plurality of support members 74. The support member 74 is configured to have a strength that can support the classification rotor 50. The support member 74 is preferably configured to guide the raw material powder 11 dispersed by the guide portion 73 outward in the rotation direction of the rotary shaft 40, and is configured as a guide vane, for example. Thereby, the distribution concentration of the raw material powder 11 in the circumferential direction can be made more uniform.

  Further, the classifying mechanism 10 includes an air flow exhaust mechanism 60 for discharging the air stream containing the fine powder 15 downward from the central portion of the classifying rotor 50. As shown in FIG. 1, the airflow exhaust mechanism 60 includes a duct 62 that is provided separately from the center of the classifying rotor 50 and that defines a flow path 61 through which an airflow containing fine powder 15 passes. The flow path 61 is preferably a cylindrical shape that is concentric with the rotary shaft 40 at least in the vicinity of the classification rotor 50 so that the airflow in the classification rotor 50 is uniform with respect to the rotation direction of the classification rotor 50. It is formed as a space. The duct 62 is connected to a suction mechanism (not shown) that sucks the gas in the duct 62. As shown in FIG. 1, in order to prevent the raw material powder 11 from entering the gap s between the rotating parts such as the classification rotor 50 and the non-rotating parts such as the duct 62, air is blown outward through the gap s. A rotor sealing air outlet 56 for jetting may be provided. The rotor seal air supply port 55 is for supplying air to the rotor seal air ejection port 56. In FIG. 1, the air supplied from the rotor seal air supply port 55 to the rotor seal air jet port 56 and ejected from the rotor seal air jet port 56 is indicated by an arrow f.

  Next, an operation when the raw material powder 11 is classified into the coarse powder 14 and the fine powder 15 using the classification mechanism of the present embodiment having the above-described configuration will be described.

  Hereinafter, the procedure of the classification process will be described. First, the classification rotor 50 is rotated at a predetermined speed via the rotating shaft 40 by a drive source such as a motor. Further, the raw material powder 11 is introduced into the raw material input port 71 of the raw material supply mechanism 70 while introducing air into the classification rotor 50 using the air introduction port 16.

  The raw material powder 11 introduced into the raw material introduction port 71 falls downward along a path 72 formed in the axial space of the rotating shaft 40 and collides with the bottom plate 76. The raw material powder 11 that has collided with the bottom plate 76 is given a centrifugal force from the bottom plate 76 and is radially dispersed outward in the radial direction of the rotating shaft 40. The raw material powder 11 dispersed by the bottom plate 76 reaches the vicinity of the classification rotor 50 through the raw material outlet 75 formed between the support members 74.

  The raw material powder 11 that has reached the vicinity of the classification rotor 50 flows into the classification rotor 50 together with the airflow from the gaps in the arrangement of the blades 51 of the classification rotor 50, whereby dispersion and classification are performed. The fine powder 15 classified by the classification rotor 50, that is, the fine powder 15 that has reached the center of the classification rotor 50 is discharged downward from the central hole formed in the bottom lid 53, and is collected through the flow path 61 and the duct 62. The On the other hand, the coarse powder 14 discharged to the outer peripheral side from the classification rotor 50 falls downward and is collected as a product.

  According to the present embodiment, as described above, the raw material powder 11 is charged into the vicinity of the classification rotor 50 through the path 72 formed in the space in the shaft of the rotating shaft 40. That is, the path of the raw material powder 11 to be charged is symmetric with respect to the circumferential direction of the classification rotor 50. For this reason, the distribution concentration of the raw material powder 11 in the classification rotor 50 can be made uniform in the circumferential direction. As a result, the classification accuracy in the classification rotor 50 can be increased as compared with the case where there is a distribution density bias. For example, the slope of the curve indicating the partial classification efficiency of the classification rotor 50 can be further increased.

  In addition, according to the present embodiment, the plurality of support members 74 arranged at predetermined intervals along the circumferential direction of the rotating shaft 40 so as to surround the bottom plate 76 are configured as guide vanes. For this reason, the path | route of the raw material powder 11 discharged | emitted from the guide part 73 and reaching the classification rotor 50 vicinity can be arranged. In addition, by appropriately designing the shape of the support member 74, the raw material powder 11 can be more uniformly dispersed in the circumferential direction. Thereby, the classification accuracy in the classification rotor 50 can be further increased.

  Further, according to the present embodiment, the structure of the raw material supply mechanism 70 can be simplified by making the path 72 of the raw material powder 11 to be input symmetrical with respect to the rotation direction of the classification rotor 50. For this reason, the maintainability of the classification mechanism 10 can be improved.

  Next, the effect of this embodiment will be described in comparison with a comparative embodiment. FIG. 2 is a diagram showing a classification mechanism 80 in a comparative form.

  In the classification mechanism 80 according to the comparative form shown in FIG. 2, the raw material charging port 13 for charging the raw material powder 11 is arranged at one place in the circumferential direction. That is, the path of the raw material powder 11 introduced into the casing is not uniform in the circumferential direction of the classification rotor 50. In this case, the raw material powder 11 is segregated in the vicinity of the classification rotor 50, and the distribution concentration of the raw material powder 11 is locally increased. As a result, the classification accuracy may be lowered.

  On the other hand, according to the present embodiment, the raw material powder 11 is uniformly introduced into the vicinity of the classification rotor 50 through the path 72 formed in the in-axis space of the rotary shaft 40, whereby the classification rotor 50. Segregation of the raw material powder 11 in the vicinity of can be suppressed.

  Note that various modifications can be made to the above-described embodiment. Hereinafter, an example of modification will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the following modifications, the description thereof may be omitted.

(First modification)
As shown in FIG. 3, a throttle portion 40 a for locally reducing the cross-sectional area of the space in the shaft may be formed on the rotating shaft 40. In the example shown in FIG. 3, the throttle portion 40 a is configured by locally projecting the inner wall of the rotating shaft 40 radially inward. By forming such a throttle portion 40a, it is possible to prevent the raw material powder 11 from being segregated in the in-axis space of the rotating shaft 40, and thereby, the raw material powder that is put in the vicinity of the classification rotor 50. 11 distribution density can be made more uniform.

  As shown in FIG. 3, the bottom plate 76 of the guide portion 73 may be formed with a protruding portion 77 that protrudes upward toward the axial space of the rotating shaft 40. In the example shown in FIG. 3, the protruding portion 77 has a cone shape that tapers toward the top. By forming such a protruding portion 77, it is possible to prevent the raw material powder 11 from being deposited at the center of the bottom plate 76. This can prevent the supply amount of the raw material powder 11 per unit time to the vicinity of the classification rotor 50 from becoming unstable. In addition, since a radially outward force is applied to the raw material powder 11 in accordance with the inclination angle of the protruding portion 77, it is possible to promote the dispersion of the raw material powder 11 radially. As a result, the classification accuracy in the classification rotor 50 can be further increased.

(Second modification)
In the above-described embodiment, the example in which the inner wall of the rotating shaft 40 defines the path 72 through which the raw material powder 11 passes is shown. That is, the example in which the inner wall of the rotating shaft 40 is in contact with the raw material powder 11 is shown. However, the present invention is not limited to this, and as shown in FIG. 4, the raw material supply mechanism 70 includes an inner cylinder 78 disposed in the axial space of the rotary shaft 40 and a connection that connects the inner cylinder 78 to the rotary shaft 40. And a member 79. In this case, the inner wall of the inner cylinder 78 defines a path 72 through which the raw material powder 11 passes. In addition, the material which comprises the rotating shaft 40, and the material which comprises the inner cylinder 78 may differ.

  According to this modification, the inner wall of the rotating shaft 40 is not in contact with the raw material powder 11. Therefore, when selecting the material constituting the rotary shaft 40, the material can be selected mainly in consideration of suitability for rotation driving without considering the durability of the raw material powder 11 and the like. For example, structural carbon steel such as S45C can be used as a material constituting the rotating shaft 40. On the other hand, as the material constituting the inner cylinder 78, a material selected in accordance with the characteristics of the powder to be processed and the user's required specifications such as stainless steel and a material having high wear resistance can be used. For this reason, in the classification mechanism 10, it is possible to optimize both the characteristics related to the rotational drive and the characteristics related to the contact with the powder. Further, according to this modification, by removing the connecting member 79, the inner cylinder 78, the classification rotor 50, etc., which are parts in contact with the powder, can be easily detached from other parts. For this reason, various cleaning methods can be adopted as a method of removing the powder adhering to the inside of the classification mechanism 10.

  In this modified example, as in the case of the first modified example shown in FIG. 3 described above, the inner cylinder 78 has a throttle portion 78a for locally reducing the cross-sectional area of the inner space of the inner cylinder 78. It may be formed. In the example shown in FIG. 4, the throttle portion 78 a is configured by locally projecting the inner wall of the inner cylinder 78 radially inward. By forming such a narrowed portion 78 a, it is possible to prevent the raw material powder 11 from being segregated in the inner space of the inner cylinder 78. Can be made more uniform.

(Third Modification)
In the above-described embodiment, the example in which the air introduction port for supplying the classification air toward the classification rotor 50 is provided only on the side of the classification rotor 50 has been described. However, the present invention is not limited to this, and as shown in FIG. 5, the classifying mechanism 10 is disposed on the side of the classifying rotor 50 and supplies an air inlet (primary air) that supplies primary classifying air toward the classifying rotor 50. In addition to the introduction port 16, a secondary air introduction port 18 disposed below the primary air introduction port 16 may be further provided. The secondary air inlet 18 is configured to supply secondary classified air for blowing upward a part of the raw material powder 11 that has fallen without reaching the blade 51 of the classification rotor 50. By further providing such a secondary air introduction port 18, it is possible to prevent the raw material powder 11 from falling without being given an opportunity for classification. Thereby, it can suppress that a fine powder mixes in the collect | recovered coarse powder 14. FIG.

  As shown in FIG. 5, a plurality of guide vanes 17 and guide vanes 19 may be arranged inside the primary air introduction port 16 and the secondary air introduction port 18, respectively.

  In this modification, it is conceivable that the duct 62 of the airflow exhaust mechanism 60 becomes longer by providing the secondary air introduction port 18. In this case, as shown in FIG. 5, the duct 62 may be configured to be disassembled into a first duct 63 and a second duct 64 that are configured to be fitted to each other.

(Fourth modification)
In the above-described embodiment, an example in which the classification mechanism 10 includes the one-stage classification rotor 50 has been described. However, the present invention is not limited to this, and the classification mechanism 10 may include a two-stage classification rotor 50 juxtaposed along the axial direction of the rotating shaft 40 as shown in FIG. In this case, the coarse powder 14a discharged from the upper classification rotor 50 to the outer peripheral side and mixed with a small amount of fine powder is introduced into the lower classification rotor 50 from the upper part of the outer peripheral portion through between the blades 51. The fine powder 15 classified by the lower classification rotor 50 is discharged downward from the center of the lower classification rotor 50 and flows into the flow path 61 of the airflow exhaust mechanism 60. On the other hand, the coarse powder 14 discharged to the outer peripheral side from the lower classification rotor 50 falls downward and is collected as a product.

(Fifth modification)
In the above-described embodiment, the example in which the classification air is supplied toward the classification rotor 50 from the air inlet 16 formed separately from the raw material inlet 71 of the raw material supply mechanism 70 has been described. However, the present invention is not limited to this. As shown in FIG. 7, the classification air may be introduced together with the raw material powder 11 from the raw material input port 71 of the raw material supply mechanism 70. The method for introducing the classified air is not particularly limited. For example, the raw material inlet 71 is configured so that the air and the raw material powder 11 are uniformly introduced by intake air. By adopting such an air introduction method, for example, the classification mechanism 10 can be connected to a pulverizer or the like and used in-line. For this reason, auxiliary machines, such as a blower for producing | generating air, can be shared by the grinder and the classification mechanism 10, and, thereby, the structure as the whole installation can be simplified.

  In addition, although some modified examples with respect to the above-described embodiment have been described, naturally, a plurality of modified examples can be applied in combination as appropriate.

10 Classification Mechanism 11 Raw Material Powder 14 Coarse Powder 15 Fine Powder 16 Air Inlet (Primary Air Inlet)
DESCRIPTION OF SYMBOLS 17 Guide vane 18 Secondary air introduction port 19 Guide vane 20 Casing 21 Main body part 22 Top plate 23 Fastener 24 Housing 25 Upper seal part 26 Lower seal part 27 Seal air supply port 28 Seal air outlet 30 Bearing 31 Inner ring 32 Outer ring 33 Rolling element 34 Sleeve 40 Rotating shaft 40a Restricted portion 41 Pulley 50 Classification rotor 51 Blade 52 Disk member 53 Bottom cover 55 Rotor seal air supply port 56 Rotor seal air outlet 60 Air flow exhaust mechanism 61 Flow path 62 Duct 70 Raw material supply mechanism 71 Raw material input Mouth 72 Path 73 Guide part 74 Support member 75 Raw material outlet 76 Bottom plate 77 Projection part 78 Inner cylinder 78a Restriction part 79 Connecting member

Claims (8)

A classification mechanism for separating raw powder into fine powder and coarse powder,
A casing,
A classification rotor which is provided inside the casing and forms a classification space;
A hollow rotating shaft disposed on the classification rotor and connected to the classification rotor;
A raw material supply mechanism for supplying raw material powder to the classification rotor,
The raw material supply mechanism is configured to convey the raw material powder toward the classification rotor through an in-shaft space formed inside the rotating shaft,
The raw material supply mechanism communicates with the space in the shaft of the rotary shaft, and has a raw material input port through which raw material powder is input and an air flow directed downward is introduced,
A classification mechanism in which the airflow introduced into the raw material inlet serves as classification air for classifying the raw material powder in the classification rotor.   The raw material supply mechanism includes a bottom plate that receives the raw material powder that has reached the lower end of the rotating shaft through the space in the shaft, and disperses the raw material powder radially outward of the rotating shaft. Classification mechanism described in 1.   The classification mechanism according to claim 2, wherein a protruding portion that protrudes upward toward the in-axis space of the rotating shaft is formed on the bottom plate.   The said raw material supply mechanism is arrange | positioned at predetermined intervals along the circumferential direction of the said rotating shaft so that the said baseplate may be enclosed, and contains the several support member which connects the said classification rotor to the said rotating shaft. Or the classification mechanism of 3.   The classification mechanism according to claim 4, wherein each support member is configured as a guide blade that guides the raw material powder dispersed by the bottom plate to the outside in the radial direction of the rotation shaft.   The classification mechanism according to any one of claims 1 to 5, wherein a throttle portion for locally reducing a cross-sectional area of the space in the shaft is formed on the rotation shaft. The raw material supply mechanism has an inner cylinder disposed in the inner space of the rotating shaft, and a connecting member that connects the inner cylinder to the rotating shaft.
The classification mechanism as described in any one of Claims 1 thru | or 6 from which the material which comprises the said rotating shaft differs from the material which comprises the said inner cylinder.   The classifying mechanism according to claim 7, wherein a throttle portion for locally reducing a cross-sectional area of the inner space of the inner cylinder is formed in the inner cylinder.

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