Rotary sorting machine and vertical mill

Abstract

Rotary sorting machine (33), comprising: a frame body (41) which is rotatable and includes an opening at an outer peripheral portion, and a plurality of rotary vanes (43; 60; 70; 80) attached to the opening of the frame body (41) at predetermined intervals in a circumferential direction, wherein each of the plurality of rotary blades (43; 60; 70; 80) comprises an inclined surface (52; 62; 72; 82) which is inclined at an acute angle relative to a contact line (T) to a rotation locus (G1) on an outer peripheral side, and which comprises a concave portion (51; 61; 71; 81) formed between an outer end (43a) and an inner end (43b), the inclined surface (52; 62; 72; 82) being formed on a front surface of the rotary blade (43; 60; 70; 80) in a rotation direction, characterized in that the inclined surface (52; 62; 72; 82) comprises a first inclined surface (53; 63; 83) which is flat and located close to the outer end (43a), and a second inclined surface (54; 64; 84) which is flat and located close to the inner end (43b), the inclined surface (52; 62; 72; 82) comprises a bending line (L) along a vertical direction between the first inclined surface (53; 63; 83) and the second inclined surface (54; 64; 84), and the bending line (L) is arranged in the middle between the rotation locus line (G1) on the outer peripheral side and a rotation locus line (G2) on an inner peripheral side of the rotary blade (43;60;70;80).

Description

Field of the invention

[0001] The present invention relates to a rotary sorting machine that grinds solid materials such as coal or biomass into fine powder and sorts the fine powder, and a vertical mill including the rotary sorting machine. Background of the invention

[0002] Solid fuel, such as coal or biomass, is used as fuel in a boiler-based combustion system to generate power. When coal is used as a solid fuel, raw coal is ground through a vertical mill to produce pulverized coal, and the resulting pulverized coal is used as fuel.

[0003] The vertical mill includes a mill table driven to rotate at a lower portion of a casing, a plurality of mill rollers arranged on an upper surface of the mill table to rotate with the rotation of the mill table and to maintain a mill load, and a rotary sorting machine arranged at an upper portion of the casing. With this configuration, when raw coal is fed to the mill table from a coal feed pipe, the fed raw coal is distributed over the entire surface due to centrifugal force to form a coal layer, and this coal layer is forced by each mill roller to be ground. The ground pulverized coal is dried by supplied air, and pulverized coal with a particle diameter equal to or smaller than a predetermined diameter is sorted by the rotary sorting machine.Thus, only pulverized coal with a suitable particle diameter is ejected to the outside.

[0004] For example, the patent documents described below describe a sorting machine for a vertical mill including a conventional rotary sorting machine. A rotary sorting machine for a roller mill described in JP H08-266923 A includes a rotary vane formed such that a width of the vane on the upper side is larger than a width of the vane on the lower side. A rotary sorting machine for a mill described in JP H07-308637 A is configured such that a trapping angle of a trapping sorting machine vane of a rotary impeller is adjusted, and an auxiliary vane extending in the direction opposite to the rotation direction is provided at a tip end on an outer peripheral side.

[0005] A classifying device described in JP 2002-018 301 A is configured such that an upper part of a rotary blade in a rotary sorting machine is more inclined to the direction of rotation than a lower part of the blade.

[0006] From DE 102 61 448 A1 a bladed classifying rotor for an air classifier is known, on which the preamble of patent claim 1 is based. Summary of the inventionTechnical problem

[0007] In a conventional rotary sorting machine, rotary vanes arranged along a vertical direction are fixed to peripheries of upper and lower rotary frames at regular intervals in a circumferential direction, and each of the rotary vanes inclines at a predetermined angle with respect to the rotation direction. On the other hand, for pulverized coal used for a coal-burning boiler, particles with a diameter of 75 μm or less are optimal, and particles with a diameter of 150 μm or more are generally unsuitable. Therefore, a sorting machine used for a vertical mill is necessary to allow pulverized coal with a particle diameter of 75 μm or less to pass through and pulverized coal with a particle diameter of 150 μm or more to be removed. Rotary vanes with a small inclination angle with respect to a rotation direction can remove coarse particles, but can also remove fine particles.Rotating blades with a large inclination angle relative to a rotation direction can pass fine particles, but can also pass coarse particles. Therefore, there is a need for a sorting machine that can remove coarse particles while allowing fine particles to pass through.

[0008] The present invention is intended to solve the above problems and aims to provide a rotary sorting machine and a vertical mill that can improve sorting efficiency. Solution to the problem

[0009] According to the present invention, a rotary sorting machine comprises the features of claim 1, specifically: a frame body that is rotatable and includes an opening at an outer peripheral portion; and a plurality of rotary vanes attached to the opening of the frame body at predetermined intervals in a circumferential direction. Each of the plurality of rotary vanes includes an inclined surface inclined at an acute angle relative to a contact line with a rotation locus on an outer peripheral side, and including a concave portion formed between an outer end and an inner end, the inclined surface being formed on a front surface of the rotary vane in a rotation direction.

[0010] The rotary blade includes an inclined surface with a concave portion on its front surface in the rotation direction. With this configuration, when the plurality of rotary blades rotate with the frame body, coarse particles with high straight-flying ability are removed outward after colliding with the inclined surface, while fine particles with low straight-flying ability are removed inward after colliding with the inclined surface. Accordingly, the plurality of rotary blades can remove coarse particles while allowing fine particles to pass through, thereby improving sorting efficiency.

[0011] The inclined surface in the rotary sorting machine includes a first inclined surface located near the outer end and a second inclined surface located near the inner end. Preferably, an inclination angle of the first inclined surface relative to the contact line is set to be greater than an inclination angle of the second inclined surface relative to the contact line.

[0012] The first inclined surface and the second inclined surface are formed on the front surface in the rotation direction. With this configuration, when the plurality of rotating blades rotate with the frame body, coarse particles with high straight-line ability are removed outward even if they collide with the second inclined surface. On the other hand, fine particles with low straight-line ability are removed inward even if they collide with the first inclined surface. Thus, the sorting efficiency can be improved.

[0013] The inclined surface in the rotary sorting machine includes a bending line along a vertical direction between the first inclined surface and the second inclined surface.

[0014] Since the first inclined surface and the second inclined surface are formed with respect to the bending line, sorting efficiency can be improved with a simple structure.

[0015] The bending line is formed in the rotary sorting machine in the middle of the rotary bucket in its width direction.

[0016] With this configuration, the first inclined surface and the second inclined surface are set as the optimal area.

[0017] Preferably, in the rotary sorting machine, an angle formed by the first inclined surface and the second inclined surface is set to be less than 180°.

[0018] With this configuration, coarse particles and fine particles can be properly sorted by the first inclined surface and the second inclined surface.

[0019] Preferably, the inclined surface in the rotary sorting machine comprises a curved surface curved from the outer end to the inner end.

[0020] Since the inclined surface is formed as the curved surface, appropriate sorting can be realized regardless of the diameter of particles to be sorted.

[0021] According to another aspect of the present invention, a vertical mill comprises: a hollow casing; a mill table having a rotation axis along a vertical direction and supported to be driven to rotate at a lower part of the casing; a mill roller disposed opposite to the mill table above the mill table and supported to be rotatable; and a rotary sorting machine according to the invention provided at an upper part of the casing for sorting the ground materials.

[0022] With this configuration, when solid materials are between the mill roller and the mill table, the mill roller rotates with the rotating force of the mill table transmitted to the mill roller via the solid materials, thereby grinding the solid materials under a pressure load. Then, particles of the ground solid materials move upward in the casing and are sorted by the rotary sorting machine. As the plurality of rotary vanes, each having the inclined surface with the concave portion on the front surface, rotate with the frame body in the rotating direction, coarse particles with high straight-flying ability are discharged outward after colliding with the inclined surface, while fine particles with low straight-flying ability are discharged inward after colliding with the inclined surface.Accordingly, the multiple rotary vanes can remove coarse particles and allow fine particles to pass through, thereby improving the sorting efficiency. Advantageous effects of the invention

[0023] In the rotary sorting machine and the vertical mill according to the present invention, the inclined surface including the concave portion formed between the outer end and the inner end is formed on the front surface of the rotary blade, whereby the sorting efficiency can be improved. Short description of the drawings Fig. 1 is a schematic view illustrating a vertical mill according to an embodiment of the present invention. Fig. 2 is a plan view illustrating a rotary sorting machine according to the embodiment of the present invention. Fig. 3 is a schematic view illustrating a rotary blade in the rotary sorting machine according to the embodiment of the present invention. Fig. 4 is a perspective view showing the rotary vane. Fig. Figure 5 is a graph showing a partial sorting efficiency with respect to a particle diameter of pulverized coal when the rotary blade rotates at 110 rpm. Fig. 6 is a diagram for describing an effect of the embodiment of the present invention when the rotary vane rotates at 110 rpm. Fig. Figure 7 is a graph showing a partial sorting efficiency with respect to a particle diameter of pulverized coal when the rotary blade rotates at 140 rpm. Fig. 8 is a diagram for describing an effect of the embodiment of the present invention when the rotary vane rotates at 140 rpm. Fig. 9 is a schematic view illustrating a rotary blade in a rotary sorting machine according to a modification of the present invention. Fig. 10 is a schematic view illustrating a rotary blade in a rotary sorting machine according to a modification of the present invention. Fig. 11 is a schematic view illustrating a rotary blade in a rotary sorting machine according to a modification of the present invention. Description of implementation examples

[0024] A preferred embodiment of a rotary sorting machine and a vertical mill according to the present invention will be described in detail below with reference to the accompanying drawings. The present invention is not limited to the embodiment, and when multiple embodiments are described, the present invention encompasses the configuration formed by combining these embodiments. Example

[0025] Fig. 1 is a schematic view illustrating a vertical mill according to an embodiment of the present invention, Fig. 2 is a plan view illustrating a rotary sorting machine according to the embodiment of the present invention, Fig. 3 is a schematic view illustrating a rotary blade in the rotary sorting machine according to the embodiment of the present invention, Fig. 4 is a perspective view showing the rotary vane, Fig. 5 is a graph showing a partial sorting efficiency with respect to a particle diameter of pulverized coal when the rotary blade rotates at 110 rpm, Fig. Fig. 6 is a diagram for describing an effect of the embodiment of the present invention when the rotary blade rotates at 110 rpm, Fig. 7 is a graph showing a partial sorting efficiency with respect to a particle diameter of pulverized coal when the rotary blade rotates at 140 rpm, and Fig. 8 is a diagram for describing an effect of the embodiment of the present invention when the rotary vane rotates at 140 rpm.

[0026] The vertical mill according to the present embodiment grinds solid materials such as coal (raw coal) or biomass. Biomass includes renewable biological organic resources, and examples of biomass include deforestation wood, wood waste, driftwood, grasses, waste materials, sludge, tires, and recyclable fuel (pellets or chips) made from these materials. Biomass is not limited to those described above.

[0027] As in Fig. As shown in Fig. 1, the vertical mill according to the present invention includes a cylindrical hollow casing 11 and a coal supply pipe 12 attached to the upper part of the casing 11. The coal supply pipe 12 supplies coal from a coal supply device (not shown) into the casing 11. The coal supply pipe 12 is arranged along the up-down direction (vertical direction) in the center of the casing 11, and its lower end extends downward.

[0028] A mill table 13 is arranged at the lower part of the casing 11. The mill table 13 is arranged opposite the lower end of the coal feed pipe 12 in the center of the casing 11. A rotating shaft 14 having a rotation axis along the vertical direction is coupled to the bottom of the mill table 13, whereby the mill table 13 is supported on the casing 11 so as to be rotatable. A worm gear 15 serving as a drive gear is fixedly coupled to the rotating shaft 14, and a worm gear 16 of a drive motor (not shown) attached to the casing 11 is engaged with this worm gear 15. Accordingly, the mill table 13 can be driven to rotate by the drive motor via the worm gear 16, the worm gear 15, and the rotating shaft 14.

[0029] An annular table liner 17 is attached to the outer periphery of the mill table 13. The table liner 17 has an inclined surface (upper surface) that rises toward the outer periphery of the mill table 13. A plurality of mill rollers 18 are arranged above the mill table 13 so as to face the mill table 13 (table liner 17), and a roller drive device 19 is provided that rotates each mill roller 18. The roller drive device 19 is, for example, a motor that can apply a driving force to the mill rollers 18.

[0030] Specifically, the roller drive device 19, which is supported by a side wall of the housing 11 with a mounting shaft 22, supports a rear end of a support shaft 21, allowing the leading end of the support shaft 21 to swing in the vertical direction. The leading end of the support shaft 21 faces the rotation axis of the mill table 13 and is mounted to be inclined downward. The mill roller 18 is mounted on the leading end of the support shaft 21.

[0031] An upwardly extending upper arm 24 is provided on the roller drive device 19 (support shaft 21), and a leading end of a push rod 26 of a hydraulic cylinder 25, which is fixed to the housing 11 to serve as a pressing device, is connected to the leading end of the upper arm 24. A downwardly extending lower arm 27 is also provided on the roller drive device 19 (support shaft 21), and the leading end thereof can be in contact with a stopper 28 fixed to the housing 11. With this configuration, when the push rod 26 moves forward through the hydraulic cylinder 25, the push rod 26 pushes the upper arm 24 to allow the roller drive device 19 and the support shaft 21 to rotate clockwise according to Fig. 1 swing around the mounting shaft 22. In this case, the swing position of the roller drive device 19 and the support shaft 21 is limited due to the contact of the lower arm 27 with the stopper 28.

[0032] Specifically, the mill roller 18 grinds coal with the mill table 13 (table lining 17). For this purpose, a predetermined clearance must be formed between the surface of the mill roller 18 and the mill table 13 (table lining 17). Since the swing position of the support shaft 21 is limited to a predetermined position by the hydraulic cylinder 25, a predetermined clearance within which coal can be introduced and ground is formed between the surface of the mill roller 18 and the surface of the mill table 13.

[0033] In this case, when the mill table 13 rotates, coal supplied to this mill table 13 is moved to the outer periphery due to centrifugal force and gets between the mill roller 18 and the mill table 13. The mill roller 18 is pressed against the mill table 13, so that a rotational force of the mill table 13 is transmitted through the coal, and the mill roller 18 can rotate with the rotation of the mill table 13.

[0034] In the present embodiment, the mill roller 18 is tapered, with a diameter decreasing toward the leading end, and has a flat surface. However, the mill roller 18 is not limited to this. For example, the mill roller 18 is tire-shaped. In the present embodiment, a plurality (three) of the mill rollers 18 are arranged at regular intervals along the rotational direction of the mill table 13. In this case, the number and arrangement of the mill rollers 18 can be appropriately adjusted depending on the sizes of the mill table 13 and the mill rollers 18, for example.

[0035] An inlet port 31, which is arranged around the mill table 13 and from which primary air is supplied, is formed at the lower part of the casing 11. An outlet port 32, which is arranged around the coal feed pipe 12 for discharging ground coal (pulverized coal), is formed at the upper part of the casing 11. The casing 11 includes a rotary separator 33 provided below the outlet port 32 to serve as a rotary sorting machine that sorts pulverized coal. The rotary separator 33 is provided on the outer periphery of the coal feed pipe 12 and can be driven to rotate by a drive device 34. A spillage discharge pipe 35 is provided at the lower part of the casing 11. The spillage discharge pipe 35 discharges spillage, such as pebbles contained in coal or metal pieces, that fall from the outer periphery of the mill table 13.

[0036] The rotary separator 33 serving as the rotary sorting machine according to the present embodiment will be described in detail here. As in Fig. 1 and Fig. 2, the rotary separator 33 includes an upper support frame 41 and a lower support frame 42 having a disc-like shape, and a plurality of rotary vanes 43 fixed to an outer peripheral portion at predetermined intervals (regular intervals) in the circumferential direction between the upper support frame 41 and the lower support frame 42. Each of the rotary vanes 43 is formed in a vane shape, provided along the up-down direction (vertical direction), and inclined with respect to the rotation direction of the rotary separator 33. In this case, since the outer diameter of the lower support frame 42 is smaller than the outer diameter of the upper support frame 41, each rotary vane 43 is formed to be inclined so that the lower end of each rotary vane 43 comes close to the rotation center of the rotary separator 33.The upper support frame 41 and the lower support frame 42 constitute a frame body of the present invention, and an area between the upper support frame 41 and the lower support frame 42 functions as an opening.

[0037] As in Fig. 3 and Fig. 4, the rotary blade 43 has an inclined surface 52 on its front surface (left surface in Fig. 4) in the rotation direction, the inclined surface 52 is inclined at an acute angle relative to a contact line 5 to a rotation locus G1 on the outer peripheral side, and has a concave portion 51 formed between an outer end 43a and an inner end 43b. In this case, the contact line T with respect to the rotation locus G is a contact line at an intersection of the rotation locus G1 of the rotary blade 43 on the outer peripheral side and the outer end 43a of the front surface of the rotary blade 43 in the rotation direction.

[0038] Specifically, the inclined surface 52 includes a first inclined surface 53 located close to the outer end 43a of the rotary blade 43 and a second inclined surface 54 located close to the inner end 43b, wherein an inclination angle α1 of the first inclined surface 53 relative to the contact line T is set larger than an inclination angle α2 of the second inclined surface 54 relative to the contact line T.

[0039] The first inclined surface 53 and the second inclined surface 54 are flat surfaces along the vertical direction, and a bending line L along the up-down direction (vertical direction) is formed between the inclined surfaces 53 and 54. The bending line L is formed at the center of the rotary blade 43 in the width direction (or the diameter direction of the rotary separator 33). A central locus O crossing the bending line L is located between the rotation locus G1 of the rotary blade 43 on the outer peripheral side and the rotation locus G2 on the inner peripheral side. Specifically, the width of the first inclined surface 53 and the width of the second inclined surface 54 are set to be approximately equal. The angle β formed by the first inclined surface 53 and the second inclined surface 54 is set to be less than 180°.

[0040] With this configuration, the outer circumference of the rotary separator 33, that is, the area between the rotation locus G1 of the plurality of rotary blades 43 on the outer circumference side and the rotation locus G2 on the inner circumference side is specified as a sorting area A. In particular, when the rotary separator 33 moves in the arrow direction in Fig. 2 and Fig. 3 rotates, particles of pulverized coal are fed into the sorting area A from the rotation locus G1 of the plurality of rotary blades 43 on the outer peripheral side into this sorting area A, and fine particles having a particle diameter smaller than a predetermined particle diameter are passed between the rotary blades 43 to enter inward, while coarse particles having a particle diameter larger than the predetermined particle diameter are discharged outward by the rotary blades 43.

[0041] In the present embodiment, a plate material having a predetermined thickness, a predetermined width, and a predetermined length (height) is bent at the central position (bending line L) in the width direction, whereby the inclined surface 52 (first inclined surface 53, second inclined surface 54) formed with the concave portion 51 is formed on the front surface of the rotary blade 43 in the rotation direction. The rear surface of the rotary blade 43 in the rotation direction has a similar structure. However, the rear surface of the rotary blade 43 in the rotation direction may have any shape as long as it does not affect the rotation resistance or sorting performance of the rotary blade 43.

[0042] If in the rotary vertical mill, which is thus constructed according to the present embodiment as in Fig. 1, when coal is fed from the coal feed pipe 12 into the casing 11, the fed coal falls down the coal feed pipe 12 to be fed to the center of the mill table 13. In this case, the mill table 13 rotates at a predetermined speed, whereby the coal fed to the center of the mill table 13 is dispersed in four directions by centrifugal force to form a constant layer on the entire surface of the mill table 13. In other words, the coal passes between the mill roller 18 and the mill table 13.

[0043] Then, the rotating force of the mill table 13 is transmitted to the mill roller 18 via the coal, so that the mill roller 18 rotates with the rotation of the mill table 13. In this case, the mill roller 18 is pressed against the mill table 13 by the hydraulic cylinder 25. Therefore, the mill roller 18 presses to grind the coal while rotating.

[0044] The coal ground by the mill roller 18, i.e., pulverized coal, moves upward while being dried by primary air supplied from the inlet port 31 into the casing 11. The upward-moving pulverized coal is sorted by the rotary separator 33, and coarse particles fall downward and are returned to the mill table 13 to be ground again. On the other hand, fine particles pass through the rotary separator 33 and are discharged from the outlet port 32 by an air blast. Spills, such as pebbles or metal pieces contained in the coal, fall outward from the outer periphery through the mill table 13 due to centrifugal force and are discharged from the spill discharge pipe 35.

[0045] In particular, when the rotary blades 43 are on the rotary separator 33, as in Fig. 3, coarse particles in the pulverized coal have a high inertial force and a high ability to fly straightly because they have a large mass (weight). Therefore, the coarse particle P1 collides with the first inclined surface 53 or the second inclined surface 54 of the rotating blade 43. In either case, the coarse particle P1 is hardly allowed to pass between the rotating blades 43, resulting in it being ejected to the outside. On the other hand, fine particles in the pulverized coal have a low inertial force and a low ability to fly straightly because they have a smaller mass (weight) than the coarse particles. Accordingly, it is difficult for the fine particles P2 to collide with the first inclined surface 53 or the second inclined surface 54 of the rotating blade 43.Even if the fine particle P2 collides with any surface, it passes between the rotary vanes 43 without being ejected to the outside and enters the inside. Accordingly, the rotary vane 43 can remove the coarse particle P1 and capture only the fine particle P2.

[0046] A result of a sorting simulation of pulverized coal by the rotary separator 33 according to the present embodiment will be described here. A diagram according to Fig. 5 shows a sorting result of pulverized coal for particles of different diameters, with the rotation speed of the rotary separator 33 (rotary blade 43) set to 110 rpm. A horizontal axis indicates a particle diameter of pulverized coal (µm), and a vertical axis indicates a partial sorting efficiency (passage rate %). A solid line indicates the result of the rotary separator 33 (rotary blade 43) according to the present embodiment, and a dashed line indicates the result of a conventional rotary separator (flat-surface rotary blade).

[0047] Generally, for pulverized coal used in a coal-fired boiler, particles with a diameter of 75 µm or less are optimal, and particles with a diameter of 150 µm or more are unsuitable. Therefore, a rotary separator in a vertical mill must pass as much pulverized coal with a particle diameter of 75 µm or less as possible and remove as much pulverized coal with a particle diameter of 150 µm or more as possible.

[0048] As can be seen from the diagram according to Fig. 5, in the sorting by the rotary separator 33 (rotary blade 43) indicated by the solid line according to the present embodiment, the rotary separator can pass almost 100% of pulverized coal having a particle diameter of 75 μm or less, reduces the pass rate of the pulverized coal having a particle diameter of more than 75 μm, and can remove almost 90% or more of pulverized coal having a particle diameter of 150 μm or more (with the pass rate of less than 10%). On the other hand, in the sorting by the conventional rotary separator indicated by the dashed line, the conventional rotary separator can pass almost 100% of pulverized coal having a particle diameter of 75 μm or less and reduces the pass rate of the pulverized coal having a particle diameter of more than 75 μm.However, the conventional rotary separator can only remove about 85% of pulverized coal with a particle diameter of 150 µm or more (with the pass rate of about 15%).

[0049] In particular, as in Fig. As shown in Fig. 6, the rotary separator 33 (rotary blade 43) according to the present embodiment can achieve the pass rate of 10% or less for sorting pulverized coal having a particle diameter of 150 μm. On the other hand, the pass rate for the same sorting according to the conventional rotary separator is 15% or more. In particular, the rotary separator 33 (rotary blade 43) according to the present embodiment removes pulverized coal having a particle diameter of 150 μm or more more efficiently than the conventional rotary separator, which means that the rotary separator 33 (rotary blade 43) has a higher sorting efficiency.

[0050] A diagram in Fig. Figure 7 shows a sorting result of pulverized coal for particles of different diameters, where the rotation speed of the rotary separator 33 (rotary blade 43) is set to 140 rpm. The rotation speed of the rotary separator 33 increases in an attempt to prevent pulverized coal with a large particle diameter from passing through and to reduce an average particle diameter of pulverized coal after sorting.

[0051] In this case, as can be seen from the diagram in Fig. 7, in the sorting by the rotary separator 33 (rotary blade 43) indicated by the solid line according to the present embodiment, the rotary separator can pass almost 100% of pulverized coal having a particle diameter of 50 μm or less, reduces the pass rate of the pulverized coal having a particle diameter of more than 50 μm, and can remove almost 95% or more of pulverized coal having a particle diameter of 100 μm or more (with the pass rate less than 5%). On the other hand, in the sorting by the conventional rotary separator indicated by the dashed line, the conventional rotary separator can pass almost 100% of pulverized coal having a particle diameter of 50 μm or less, and reduces the pass rate of the pulverized coal having a particle diameter of more than 50 μm.However, the conventional rotary separator can only remove about 95% of pulverized coal with a particle diameter of 100 µm or more (with the pass rate of about 5%).

[0052] In particular, as in Fig. As shown in Fig. 8, the rotary separator 33 (rotary blade 43) according to the present embodiment can achieve the pass rate of approximately 0% for sorting pulverized coal having a particle diameter of 150 μm. On the other hand, the pass rate for the same sorting according to the conventional rotary separator is approximately 3%. In particular, the rotary separator 33 (rotary blade 43) according to the present embodiment removes pulverized coal having a particle diameter of 150 μm or more more efficiently than the conventional rotary separator, which means that the rotary separator 33 has a higher sorting efficiency.

[0053] As described above, in the rotary sorting machine according to the present embodiment, the rotary separator 33 is configured such that a plurality of rotary vanes 43 are fixed to the outer peripheral portion at predetermined intervals in a circumferential direction between the upper support frame 41 and the lower support frame 42, which have a disk-like shape, and the inclined surface 52, which is inclined at an acute angle relative to the contact line T with respect to the rotation locus G1 on the outer peripheral side and includes the concave portion 51 formed between the outer end 43a and the inner end 43b, is formed on the front surface of each of the rotary vanes 43 in the rotation direction.

[0054] Each of the rotary vanes 43 includes the inclined surface 52 with the concave portion 51 on the front surface in the rotation direction. With this configuration, when the rotary vanes 43 rotate, coarse particles with high straight-flying ability are removed outward after colliding with the inclined surface 52, while fine particles with low straight-flying ability are removed inward after colliding with the inclined surface 52. Accordingly, the plurality of rotary vanes 43 can remove coarse particles and allow fine particles to pass through, thereby improving the sorting efficiency.

[0055] In the rotary sorting machine according to the present embodiment, the first inclined surface 53 located near the outer end 43a of the rotary blade 43 and the second inclined surface 54 located near the inner end 43b are formed as the inclined surface 52, and the inclination angle α1 of the first inclined surface 53 relative to the contact line T is set larger than the inclination angle α2 of the second inclined surface 54 relative to the contact line T. With this configuration, when the rotary blades 43 rotate, coarse particles with high straight-flying ability are removed outward even if they collide with the inside-disposed second inclined surface 54. On the other hand, fine particles with low straight-flying ability are removed inward even if they collide with the outside-disposed first inclined surface 53. Thus, sorting efficiency can be improved.

[0056] In the rotary sorting machine according to the present embodiment, each of the first inclined surface 53 and the second inclined surface 54 is a flat surface along the vertical direction, and the bending line L along the vertical direction is formed between the inclined surfaces 53 and 54. Forming the first inclined surface 53 and the second inclined surface 54 relative to the bending line L can improve the sorting efficiency with a simple structure.

[0057] In the rotary sorting machine according to the present embodiment, the bending line L is formed at the center of the rotary blade 43 in the width direction. With this configuration, the first inclined surface 53 and the second inclined surface 54 can be set as an optimal area.

[0058] In the rotary sorting machine according to the present embodiment, the angle formed by the first inclined surface 53 and the second inclined surface 54 is set to less than 180°. With this configuration, coarse particles and fine particles can be properly sorted by the first inclined surface 53 and the second inclined surface 54.

[0059] A vertical mill according to the present embodiment includes a hollow casing 11, a mill table 13 having a rotational axis along a vertical axis and supported to be driven to rotate at a lower part of the casing 11, a mill roller 18 disposed opposite the mill table 13 above the mill table 13 and supported to be rotatable, and a rotary separator 33 provided in the casing 11 at its lower part as a rotary sorting machine capable of sorting pulverized coal. Each of a plurality of rotary vanes 43 mounted on an outer periphery of the rotary separator 33 includes an inclined surface 52 inclined at an acute angle relative to the contact line T to the rotation locus G1 on the outer peripheral side, and having the concave portion 51 formed between the outer end 43a and the inner end 43b.wherein the inclined surface 52 is formed on the front surface of each of the rotary blades 43 in a rotational direction.,

[0060] With this configuration, when coal passes between the mill roller 18 and the mill table 13, the mill roller 18 rotates with the rotating force of the mill table 13 transmitted to the mill roller 18 via the coal, thereby grinding the coal with a pressure load. Then, the ground pulverized coal moves upward in the casing 11 and is sorted by the rotary separator 33. In this case, when the rotary vanes 43 rotate, coarse particles with high straight-flying ability are removed outward after colliding with the inclined surface 52, while fine particles with low straight-flying ability are moved inward after colliding with the inclined surface 52. Accordingly, the plurality of rotary vanes 43 can remove coarse particles and allow fine particles to pass through, thereby improving the sorting efficiency.

[0061] In the above embodiment, the first inclined surface 53 and the second inclined surface 54 are formed at different angles on the front surface of the rotary vane 43 in the rotation direction. However, the invention is not limited to this. Modifications of the rotary vane in the rotary sorting machine according to the present embodiment will be described below.

[0062] Fig. 9 to 11 are schematic views illustrating a rotary bucket in a rotary sorting machine according to modifications of the present invention.

[0063] In a first modification, as in Fig. 9, a rotary blade 60 has an inclined surface 62 inclined at an acute angle relative to a contact line T to a rotation locus G1 on an outer peripheral side and a concave portion 61, the inclined surface 62 being formed on a front surface (left surface in Fig. 9) in a rotational direction. A first inclined surface 63, a second inclined surface 64, and a third inclined surface 65 are formed from the outer side of the rotary blade 60 as the inclined surface 62, wherein the inclination angle of the first inclined surface 63 is the largest and the inclination angle of the third inclined surface 65 is the smallest.

[0064] Each of the inclined surfaces 63, 64, and 65 constitutes a flat surface along the vertical direction, and bending lines L1 and L2 along the up-down direction (vertical direction) are formed between each surface. The width of each of the inclined surfaces 63, 64, and 65 is adjusted to be approximately equal by these bending lines L1 and L2. The angle formed by the first inclined surface 63 and the third inclined surface 65 is set to be less than 180°.

[0065] This rotary vane 60, like the rotary vane 43, can allow fine particles with a particle diameter smaller than a predetermined particle diameter to pass through while expelling coarse particles with a particle diameter larger than the predetermined particle diameter to the outside. The number of inclined surfaces is not limited to two or three. Four or more inclined surfaces can be formed.

[0066] In a second modification, as in Fig. 10, a rotary blade 70 has an inclined surface 72 which is inclined at an acute angle relative to a contact line T to a rotation locus G1 on an outer peripheral side, and which has a concave portion 71, the inclined surface 72 being formed on a front surface (left surface in Fig. 10) in a rotation direction. The inclined surface 72 is a curved surface curved from an outer end to an inner end. This rotary blade 70, like the rotary blade 43, can allow fine particles with a particle diameter smaller than a predetermined particle diameter to pass through while rotating and expel coarse particles with a particle diameter larger than the predetermined particle diameter to the outside. The rotary blade 70 has the inclined surface 72, which is the curved surface, and can thus appropriately sort pulverized coal regardless of the particle diameters of the pulverized coal to be sorted.

[0067] In a third modification, as in Fig. 11, a rotary blade 80 has an inclined surface 82 which is inclined at an acute angle relative to a contact line T to a rotation locus G1 on an outer peripheral side, and which has a concave portion 81, the inclined surface 82 being formed on a front surface (left surface in Fig. 11) in a rotational direction. A first inclined surface 83 and a second inclined surface 84 are formed from the outer side of the rotary blade 80 as the inclined surface 82, with the inclination angle of the first inclined surface 83 set larger. Each of the inclined surfaces 83 and 84 has almost the same shape as each of the inclined surfaces 53 and 54 of the rotary blade 43.

[0068] The rear surface (right surface in Fig.11) The rotary blade 80 is flat in the rotation direction, so that the rotational resistance or sorting performance is not affected. This rotary blade 80, like the rotary blade 43, can allow fine particles with a particle diameter smaller than a predetermined particle diameter to pass through while rotating, and can expel coarse particles with a particle diameter larger than the predetermined particle diameter to the outside.

[0069] In the above embodiment, the rotary separator 33 is configured such that the plurality of rotary vanes 43 having a disc-like shape are fixed to its outer peripheral portion between the upper support frame 41 and the lower support frame 42 at predetermined intervals in a circumferential direction. However, the shapes of the support frames 41 and 42 and the rotary vanes 43 are not limited to these in the embodiment.

[0070] The rotary sorting machine according to the present invention is applied to a vertical mill in the above description. However, the present invention is not limited to this. The rotary sorting machine can be applied to an apparatus that sorts substances other than pulverized coal. List of reference symbols 11 housings 12 Coal feed pipe 13 Mill table 17 Table lining 18 mill roller 19 Roller drive device 25 hydraulic cylinders 33 Rotary separator (rotary sorting machine) 41 upper support frame (frame body) 42 lower support frame 43, 60, 70, 80 rotary vane 51, 61, 71, 81 concave section 52, 62, 72, 82 inclined surface 53, 63, 83 first inclined surface 54, 64, 84 second inclined surface 65 third inclined surface

Claims

[1] Rotary sorting machine (33), comprising: a frame body (41) which is rotatable and includes an opening at an outer peripheral portion, and a plurality of rotary vanes (43; 60; 70; 80) attached to the opening of the frame body (41) at predetermined intervals in a circumferential direction, wherein each of the plurality of rotary blades (43; 60; 70; 80) comprises an inclined surface (52; 62; 72; 82) which is inclined at an acute angle relative to a contact line (T) to a rotation locus (G1) on an outer peripheral side, and which comprises a concave portion (51; 61; 71; 81) formed between an outer end (43a) and an inner end (43b), the inclined surface (52; 62; 72; 82) being formed on a front surface of the rotary blade (43; 60; 70; 80) in a rotation direction, characterized by , that the inclined surface (52; 62; 72; 82) comprises a first inclined surface (53; 63; 83) which is flat and located close to the outer end (43a), and a second inclined surface (54; 64; 84) which is flat and located close to the inner end (43b), the inclined surface (52; 62; 72; 82) comprises a bending line (L) along a vertical direction between the first inclined surface (53; 63; 83) and the second inclined surface (54; 64; 84), and the bending line (L) is arranged in the middle between the rotation locus line (G1) on the outer peripheral side and a rotation locus line (G2) on an inner peripheral side of the rotary blade (43;60;70;80). [2] The rotary sorting machine (33) according to claim 1, wherein an inclination angle of the first inclined surface (53;63;83) relative to the contact line (T) is set to be larger than an inclination angle of the second inclined surface (54;64;84) relative to the contact line (T). [3] The rotary sorting machine (33) according to claim 2, wherein an angle formed by the first inclined surface (53;63;83) and the second inclined surface (54;64;84) is set to less than 180°. [4] The rotary sorting machine (33) of claim 1, wherein the inclined surface (52;62;72;82) comprises a curved surface curved from the outer end (43a) to the inner end (43b). [5] Vertical mill, comprising: a hollow housing (11), a mill table (13) having a rotation axis along a vertical direction and supported to be driven to rotate at a lower part of the housing (11), a mill roller (18) arranged opposite the mill table (13) above the mill table (13) and supported to be rotatable, and a rotary sorting machine (33) according to any one of claims 1 to 4, provided at an upper part of the casing (11) for sorting the ground materials.

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