Rotary classifier and vertical mill

Abstract

Rotation classifiers (33), comprising: a rotating shaft (40) which is supported around a rotation axis (C) extending in a vertical direction for rotation in one direction; a frame body (41) which is supported by the rotating shaft (40) and includes an opening (47) on an outer circumference of the frame body (41); a plurality of powder outlets (45) which are provided along the direction of rotation and open in an upper section of the frame body (41); a plurality of wings (48) extending vertically at the opening (47) on the outer circumference of the frame body (41) and provided along the direction of rotation; a narrowing section designed in such a way as to reduce the distance from the wings (48) to the rotating shaft (40), wherein the narrowing section comprises an annular element (1) which is provided continuously in the direction of rotation and extends from the side of the wings (48) to the side of the rotating shaft (40) such that the distance of the side of the rotating shaft (40) from the wings (48) to the rotating shaft (40) is narrowed, and wherein the annular element (1) is provided inside the frame body (41) from the wings (48).

Description

[0001] The present invention relates to a rotary classifier that pulverizes a solid material, such as coal or biomass, into powder and then classifies the powder, and a vertical mill attached to the rotary classifier.

[0002] In a combustion plant, such as a thermal power plant, a solid fuel, such as coal or biomass, is used as fuel. When this coal or similar material is used as the solid fuel, coal dust is produced by pulverizing raw coal in a vertical mill, and the resulting coal dust is used as fuel.

[0003] The vertical mill consists of a mill table, which is rotatably driven in a lower section of a housing, a plurality of mill rollers, which rotate on an upper surface of the mill table and can apply a pulverizing load, and a rotary classifier located in an upper section of the housing. When raw coal is fed to the mill table from the coal feed line, centrifugal force distributes it across the entire surface to form a coal layer. This coal layer is pulverized by being pushed by each of the mill rollers. After drying by air, the coal dust is classified by the rotary classifier into predetermined particle diameters or smaller, and only the coal dust with a corresponding particle diameter is discharged.

[0004] A roller mill structure, as disclosed in JP 2009-195 897 A, typically aims to distribute powder that has passed through a classifier evenly to four powder outlets when the powder, such as coal dust pulverized by a mill roller, is pneumatically conveyed. This roller mill structure is configured such that powder obtained by pulverizing a material fed into a mill body (housing) is discharged circumferentially by pneumatic conveying from the powder outlets of an upper housing section, which is divided into multiple sections. The roller mill structure comprises a mill table rotating within the housing, a plurality of rollers rolling on the mill table and pulverizing the material, and the classifier located upstream of the powder outlets.A rectifier, which partially narrows a cross-sectional area of ​​a flow path, is provided on a section of a flow path of a powder stream that flows into the classifier and towards the powder outlets.

[0005] For example, a vertical pulverizer disclosed in JP 2 617 832 B2 aims to obtain a product with a particle size distribution that, after classification, exhibits strong classification properties with little variation in the particle size distribution within the product. The vertical pulverizer comprises a rotary separator, including a vertical drive shaft rotatably supported in the center of a classification chamber, and a plurality of planer-type classification vanes that rotate integrally around the drive shaft. In the vertical pulverizer, the pulverization of a raw material is achieved by a rotary table located in a lower section of the classification chamber and mill rollers that are advanced and driven by the rotary table. The classification vanes have an angle of inclination, with one diameter of which increases from downstream to upstream in a side view.One outer diameter side of the classification wings is designed to be recessed relative to the inner diameter side in a top view, with respect to the direction of rotation. The arrow angles of the classification wings differ between the upper and lower halves.

[0006] According to JP 2009-195 897 A, the rectifier is a movable blade operated to adjust the cross-sectional area of ​​a flow path. Uniform distribution of a powder to multiple pulverized coal lines is improved by changing the opening degree of the movable blade and adjusting the blocked quantity of circulating particles. However, the blocking effect is limited by the movable blade alone, and uniform distribution remains insufficient. The movable blade is located on the upper side of the classifier's interior, which has a relatively large volume. Consequently, on the lower side of the classifier's interior, which has a relatively small volume, variations in the powder flow velocity are created, making it difficult to achieve a sufficiently uniform distribution.

[0007] According to JP 2 617 832 B2, the classifying wings must be divided into an upper and a lower half because the swept angles of the classifying wings differ between the upper and lower halves. For example, such a division of approximately 60 classifying wings in one circumferential direction of the classifier reduces its manufacturability. Furthermore, assembly errors are more likely to occur, and the precision of the swept angle of each classifying wing becomes inaccurate, thus impairing the uniform distribution of the powder to the coal dust ducts.

[0008] From JP 5 716 272 B2, a vertical roller mill for crushing pulverized coal is known, comprising a cylindrical housing on a base 6 and a coal feed / discharge section at the top of the housing. A rotatable crushing table with a table drive device is housed in the lower part of the housing. A primary air chamber is formed between the base and the crushing table, and a classification chamber is located above the crushing table within the housing. A rotary classifier is positioned on a rotating shaft in the upper part of the classification chamber and is connected to and rotated by a rotary drive element. The rotary classifier is provided with a number of strip-shaped blades arranged at a predetermined angular interval in the circumferential direction and supported by the rotating shaft via a blade carrier.The blades are inclined in such a way that the upper end is away from the center and the angle of inclination formed by the blades is 60 to 40 degrees to a horizontal plane.

[0009] From US Patent 2009 / 0065403A1, a rotary classifier (centrifugal air classifier) ​​is known, comprising a rotor provided in a housing and including a dispersion plate and a rotating plate, the plates being attached to a rotating shaft of the rotor with a space between them in an axial direction, and a plurality of rotor blades held between outer circumferential portions of the two plates. Guide vanes, provided outside the rotor blades and fixed to the housing, face the rotor blades across a classification space.A radial air inlet is provided in the housing to supply the classification chamber with air for classification by the guide vanes. A powder inlet is provided in an upper part of the housing, opposite the dispersion plate. A fine powder outlet for discharging classified fine powder to the outside of the classifier is provided centrally as a ring around the rotating shaft. A partition plate is attached to the rotor blades to divide the classification chamber formed between the dispersion plate and the rotating plate into several levels.

[0010] The present invention solves the problem described above and aims to provide a rotary classifier and a vertical mill that can improve the uniform distribution of a powder.

[0011] To achieve the above-described objective, a rotary classifier according to the invention comprises the features of claim 1, including, among other things: a rotating shaft which is supported in a rotational direction about an axis of rotation extending in a vertical direction; a frame body which is supported by the rotating shaft and comprises an opening on the outer circumference of the frame body; a plurality of powder outlets which are provided along a direction of rotation and open in an upper section of the frame body; a plurality of wings which extend in the vertical direction at the opening on the outer circumference of the frame body and are provided along the direction of rotation; and a narrowing section which is provided such that the distance from the wings to the rotating shaft is narrowed.

[0012] According to this rotary classifier, the circumferential flow velocity is increased by conserving torque when an upward flow, rising inside a frame body due to a circumferential flow caused by the rotation and movement of vanes, flows through a section restricted by the constricting section. This increase in circumferential flow velocity reduces the flow velocity variation in the circumferential direction. Consequently, the uniform distribution of powder discharged to the outside of the frame body can be improved at each of the powder outlets.

[0013] In the rotary classifier according to the invention, the narrowing section comprises an annular element which is provided continuously in the direction of rotation and extends from the wing side to the rotating shaft side, such that the distance between the rotating shaft side and the wings is narrowed.

[0014] According to this rotary classifier, the orbital flow velocity is increased by maintaining torque when the upward flow, which rises inside the frame body due to a circulating flow caused by the rotation and movement of the vanes, flows through a section restricted by the annular element, which acts as the constricting section. This increase in orbital flow velocity reduces the flow velocity variation in the circumferential direction. Consequently, the uniform distribution of powder discharged to the outside of the frame body can be improved at each of the powder outlets.

[0015] In a rotation classifier of a preferred embodiment, the annular element comprises an inclined surface which is formed upwards from the wing side to the rotating shaft side in a lower section.

[0016] According to this rotary classifier, the upward flow, which rises inside the frame body due to a circulating flow caused by the rotation and movement of the vanes, is corrected by the inclined surface of the annular element. Therefore, drift, in which the powder flow velocity distribution deviates within an interior area of ​​the frame body, is further reduced. Consequently, a significant improvement in the uniform distribution of the powder discharged to the outside of the frame body can be achieved at each of the powder outlets.

[0017] In a rotation classifier of a preferred embodiment, the angle of the annular element with respect to a horizontal surface of the inclined surface is set in a range between -50 degrees and 50 degrees.

[0018] According to this rotation classifier, a corrective effect on the upward flow can preferably be achieved by adjusting the angle with respect to the horizontal surface of the inclined surface in the range between -50 degrees and 50 degrees.

[0019] A rotation classifier of a preferred embodiment comprises a lower part which extends upwards from an outer circumferential side of an inner bottom of the frame body in the direction of the rotating shaft side, and which comprises a surface inclined continuously in the direction of rotation.

[0020] According to this rotary classifier, the upward flow, which rises inside the frame body due to a circulating flow caused by the rotation and movement of the vanes, is corrected by the inclined surface of the lower section. Therefore, drift, in which the powder flow velocity distribution deviates within an interior area of ​​the frame body, is further reduced. Consequently, through synergy with the action of the annular element, a significant improvement in the uniform distribution of the powder discharged to the outside of the frame body can be achieved at each of the powder outlets.

[0021] In a rotation classifier of a preferred embodiment, the angle of the lower part with respect to the horizontal surface of the inclined surface is set in a range between 20 degrees and 60 degrees.

[0022] According to this rotation classifier, a corrective effect on the upward flow can preferably be achieved by adjusting the angle with respect to the horizontal surface of the inclined surface in the range between 20 degrees and 60 degrees.

[0023] A vertical mill according to the invention has the features of claim 6 and comprises a hollow housing, a mill table which is provided in a lower section in the housing and is rotated about an axis of rotation along a vertical direction, a mill roller which is provided opposite a circumferential surface in an upper surface of the mill table and is rotatably supported, and a rotary classifier according to the invention which is provided in an upper section in the housing.

[0024] According to this vertical mill, the uniform distribution of powder discharged to the outside of the frame body at each powder outlet can be improved by including a constricting section in the rotary classifier. Therefore, when a solid material, such as coal (crude coal) or biomass, is pulverized, the resulting coal dust can be conveyed uniformly to a combustion plant. Furthermore, this vertical mill allows for variation in the amount of coal dust discharged from each powder outlet by means of the constricting section.

[0025] According to the present invention, the uniform distribution of a powder to a coal dust pipeline can be improved. Fig. Figure 1 is a schematic representation of a vertical mill according to an embodiment of the present invention. Fig. Figure 2 is a cross-sectional view of a rotary classifier according to the embodiment of the present invention. Fig. 3 is a cross-sectional view along AA in Fig. 2. Fig. Figure 4 is a graph showing the flow velocity deviation of the coal dust released from the powder outlets during classification. Fig. Figure 5 is a cross-sectional view of another example of the rotary classifier according to the embodiment of the present invention. Fig. Figure 6 is a cross-sectional view of another example of the rotary classifier according to the embodiment of the present invention. Fig. Figure 7 is a cross-sectional view of another, non-inventive example of the rotary classifier.

[0026] Embodiments of the present invention are described below with reference to the drawings. Note, however, that the present invention is not limited to these embodiments. Furthermore, the embodiments described below include those that can be easily interchanged by those skilled in the art or those that are substantially the same.

[0027] Fig. Figure 1 is a schematic representation of a vertical mill according to an embodiment of the present invention. The vertical mill of the present invention pulverizes a solid material, such as coal (raw coal) and biomass, and feeds the coal dust to a combustion plant, such as a thermal power plant, as fuel. Here, biomass refers to an organic resource derived from a renewable organism, for example, thinning wood, wood waste, driftwood, grasses, waste, sludge, a tire, and recycled fuel (such as pellets and wood chips) that uses these as raw materials, but is not limited to these.

[0028] In the vertical mill of the present embodiment, a housing 11, as shown in Fig. Figure 1 shows a cylindrical hollow form. A coal feed line 12 is mounted in an upper section of the housing 11. The coal feed line 12 supplies the interior of the housing 11 with coal from a coal feed device (not shown) and is located in a central position along the vertical direction of the housing 11. An upper end section of the coal feed line 12 extends on the outside of the housing 11, and a lower end section of the coal feed line 12 extends towards a lower section of the inside of the housing 11.

[0029] A mill table 13 is provided at the lower section of the housing 11. The mill table 13 is positioned opposite the lower end section of the coal feed line 12 in a central position within the housing 11. A lower portion of the mill table 13 is connected to a rotary shaft (not shown) with an axis of rotation along the vertical direction. The rotation of the mill table 13 is driven by the rotary shaft.

[0030] A ring-shaped table lining 17 is attached to the mill table 13 on one of its outer circumferences. This table lining 17 has a front surface (upper surface) that slopes upwards towards the outer edge of the mill table 13. A plurality of mill rollers 18 are positioned opposite the upper surface of the mill table 13 (table lining 17) above the mill table 13. The mill rollers 18 are mounted on a support shaft 21. A rear end section of the support shaft 21 is supported by a roller drive device 19. The roller drive device 19 is supported by a side wall section of the housing 11 via a mounting shaft 22. This allows a tip section of the support shaft 21 to oscillate vertically. The tip section of the support shaft 21 is opposite a rotation axis side of the mill table 13 and is inclined downwards.The mill roller 18 is attached to the tip section of the support shaft 21. A plurality of mill rollers 18 (for example, three) are provided and are spaced equally along the direction of rotation of the mill table 13. The number and arrangement of the mill rollers 18 can be determined according to the dimensions and other specifications of the mill table 13, the mill rollers 18, and the like.

[0031] The roller drive device 19 (support shaft 21) is provided with an upper arm 24, which extends upwards. A tip section of the upper arm 24 is connected to a tip section of a push rod 26 of a hydraulic cylinder 25, which serves as a thrust device and is attached to the housing 11. The roller drive device 19 (support shaft 21) is provided with a lower arm 27, which extends downwards. A tip section of the lower arm 27 can contact a stop 28, which is attached to the housing 11. When the push rod 26 is accordingly advanced by the hydraulic cylinder 25, the push rod 26 pushes the upper arm 24. Then the roller drive device 19 and the support shaft 21 rotate and move in a clockwise direction. Fig. 1, wherein the mounting shaft 22 serves as a pivot point. Because the lower arm 27 encompasses the stop 28 at this point, the rotational position of the roller drive device 19 and the support shaft 21 is defined.

[0032] The mill rollers 18 pulverize coal between the mill rollers 18 and the mill table 13 (table lining 17). A predetermined clearance must be maintained between the front surfaces of the mill rollers 18 and the front surface of the mill table 13 (table lining 17). Accordingly, the support shaft 21 is set in a predetermined rotational position by the hydraulic cylinder 25. This ensures a predetermined clearance into which coal can be introduced and pulverized between the front surfaces of the mill rollers 18 and the front surface of the mill table 13. When the mill table 13 rotates, the coal supplied to the mill table 13 is moved by centrifugal force to an outer circumferential side and enters the space between the mill rollers 18 and the mill table 13. As the mill rollers 18 are pushed towards the side of the mill table 13, a rotational force of the mill table 13 is transmitted via the coal to the mill rollers 18.The mill rollers 18 can therefore rotate together with the rotation of the mill table 13.

[0033] The housing 11 is provided with an inlet opening 31, which is positioned on the circumference of an outer edge of the mill table 13, i.e., on the lower side of the housing 11. Air is supplied to the interior of the housing 11 via the inlet opening 31. The housing 11 is provided with an outlet opening 32, which is positioned on the circumference of a side section of the coal feed line 12 in an upper section of the housing 11. The outlet opening 32 is a coal dust line. The pulverized coal (coal dust) described above is discharged from the outlet opening 32 together with the air supplied to the interior of the housing 11. The housing 11 is provided with a rotary separator 33, a rotary classifier that classifies the coal dust, located below the outlet opening 32, i.e., within the housing 11.The rotary separator 33 is rotatably supported in an outer circumferential section of the coal feed line 12 and is driven by a drive device 34. The housing 11 is provided with a foreign material discharge 35 in its lower section. The foreign material discharge 35 removes foreign material (output) falling from an outer circumferential section of the rotating mill table 13, such as a stone or a piece of metal mixed into the coal.

[0034] The rotary separator 33, which serves as the rotary classifier of the present embodiment, is described in detail. Fig. Figure 2 is a cross-sectional view of the rotary classifier according to the present embodiment. Fig. 3 is a cross-sectional view along AA in Fig. 2. In Fig. Figure 2 shows a right half-section and the left half-section is not shown, because the configuration is symmetrical with a rotation axis C as a reference.

[0035] As in Fig. 2 and Fig. As shown in Figure 3, the rotary separator 33 comprises a rotating shaft 40 with a cylindrical shape. The rotating shaft 40 extends along the vertical direction, such that it surrounds the coal feed line 12, and is supported so that it rotates around the axis of rotation C, which is a center point of the cylindrical shape. The rotating shaft 40 is driven to rotate by the drive device 34 described above.

[0036] The rotary separator 33 has a frame body 41. The frame body 41 comprises an upper support frame 42 and a lower support frame 43, which have circular shapes. The center of each circular shape of the upper support frame 42 and the lower support frame 43 is located on the axis of rotation C of the rotating shaft 40, and the upper support frame 42 and the lower support frame 43 are supported by the rotating shaft 40. The upper support frame 42 and the lower support frame 43 are mutually supported by a flat bar-shaped support element 44, which extends vertically between the upper support frame 42 and the lower support frame 43. A plurality of the support elements 44 (for example, six) are evenly spaced along the direction of rotation of the axis of rotation C (direction of rotation of the rotating shaft 40). The frame body 41 is configured to be blocked vertically by the upper support frame 42 and the lower support frame 43. As shown in Fig. As shown in Figure 3, a plurality of arc-shaped powder outlets 45 (for example, at four locations) are evenly spaced along the direction of rotation, which has its center around the axis of rotation C, in the support frame 42. The powder outlets 45 are connected to the outlet opening 32, which is a coal dust duct. A movable vane 49 is provided corresponding to a rear side of each of the powder outlets 45 in the direction of rotation, i.e., a lower side of the upper support frame 42. The movable vane 49 is driven to rotate by a drive device (not shown) via a shaft 49a, which extends vertically over a range of a predetermined angle. Thus, when the frame body 41 rotates, the movable vane 49 blocks the powder flow from the inside of the frame body 41 and directs the powder flow to each of the powder outlets 45.A movable shovel, disclosed in JP 2009-195897A, can be used as the movable shovel 49. The frame body 41 has an opening 47, which is open in a section that is an outer circumferential section, between the circumferential edges of the upper support frame 42 and the lower support frame 43.

[0037] With respect to the frame body 41, wings 48 are provided in the opening 47 between the upper support frame 42 and the lower support frame 43. The wings 48 extend vertically in the opening 47 along the outer circumferential section of the frame body 41. A plurality of wings 48 (for example, six) are provided along the direction of rotation. The wings 48 are formed in a flat-plate shape and are inclined to the axis of rotation C such that an upper end face of the wings 48 is separated from the rotating shaft 40 and a lower end face approaches the rotating shaft 40.In a rotational movement around the axis of rotation C, in which the rotating shaft 40 is driven to rotate, the vanes 48 classify the particles when a particle of the coal dust enters between the plurality of vanes 48 by allowing fine powder with a smaller particle size than a predetermined particle size to pass between the vanes 48, and by preventing the passage of coarse powder with a larger particle size than a predetermined particle size between the vanes 48 by blocking the coarse powder from passing outwards from the vanes 48.

[0038] As in Fig. As shown in Figure 1, in the vertical mill of the present embodiment, configured as above, when coal is fed into the coal feed line 12, the coal falls into the coal feed line 12 and is directed to a central section on the mill table 13, i.e., into the housing 11. Since the mill table 13 rotates at a predetermined speed at this time, the coal fed to the central section on the mill table 13 moves outwards by the action of centrifugal force. Therefore, a specific layer is formed across the entire surface of the mill table 13. This means that the coal reaches the area between the mill rollers 18 and the mill table 13.

[0039] The rotational force of the mill table 13 is then transmitted to the mill rollers 18 via the coal, and the mill rollers 18 rotate together with the rotation of the mill table 13. At this point, the mill rollers 18 are pushed by the hydraulic cylinder 25 and supported against the side of the mill table 13. Consequently, the mill rollers 18 push and pulverize the coal as they rotate.

[0040] The coal pulverized by the mill rollers 18, that is, the coal dust, is dried and lifted by air supplied to the housing 11 through the inlet opening 31. The lifted coal dust is classified by the rotary separator 33. The coarse powder falls and returns to the mill table 13, where it is pulverized again. The fine powder, on the other hand, passes through the rotary separator 33, is carried by the airflow, and is discharged through the outlet opening 32. The discharged material, such as a stone or a piece of metal mixed in with the coal, falls from the outer circumferential edge of the mill table 13 due to centrifugal force and is removed by the foreign matter discharge 35.

[0041] This means that when the vanes 48 rotate and move within the rotary separator 33, the coarse powder has a large inertial force and high linearity because its mass (weight) in the coal dust is significant. Therefore, the coarse powder collides with the vanes 48, making it difficult for it to pass between them, and it is blocked to the outside of the frame body 41, preventing it from being expelled. The fine powder, on the other hand, has a small inertial force and low linearity because its mass (weight) in the coal dust is less than that of the coarse powder. Therefore, it is less likely that the fine powder will collide with the vanes 48. Even if a collision does occur, the fine powder is not blocked to the outside of the frame body 41, but passes between the vanes 48 and penetrates the interior of the frame body 41.In this way, the wings 48 can exclude the coarse powder and allow only the fine powder into the interior of the frame body 41.

[0042] The rotary separator 33 in the vertical mill of the present embodiment is provided with a narrowing section in the configuration described above. As in Fig. 2 and Fig. As described in Figure 3, the narrowing section is provided to reduce the distance from the wings 48 to the rotating shaft 40 and is configured as an annular element 1 which is continuous in the direction of rotation and extends from the wing 48 side to the rotating shaft 40 side.

[0043] The annular element 1 is a ring-shaped round plate with an open center, positioned between the upper support frame 42 and the lower support frame 43. The outer edge 1a of the annular element 1 is supported by the wings 48, and the inner edge 1b is supported by the support part 44. The annular element 1 is located inside the frame body 41, separated from the wings 48. Accordingly, the annular element 1, acting as the narrowing section, is designed to reduce the distance S1 from the outer edge 1a (i.e., the inner edge of the wings 48) to the pivot shaft 40 to a distance S2 from the inner edge 1b to the pivot shaft 40 by a width between the outer edge 1a and the inner edge 1b of the annular element 1, and to limit the distance between the upper support frame 42 and the lower support frame 43 within the frame body 41.

[0044] As described above, the fine powder in the coal dust is introduced into the frame body 41 through the vanes 48. The fine powder fed into the interior of the frame body 41 rises inside the frame body 41 as it rotates along the circumference of the rotating shaft 40 due to a circulating flow caused by the rotation and movement of the vanes 48. In this way, the fine powder rises inside the frame body 41, then reaches each of the powder outlets 45 and is then discharged from the outlet opening 32 through the powder outlets 45.

[0045] In the present embodiment, the annular element 1 is provided, which serves as the constricting section. Therefore, the circumferential flow velocity is increased by maintaining torque when an upward flow, rising inside the frame body 41 due to the passage of the circumferential flow, is drawn to an inner area between the inner edge 1b and the rotating shaft 40, which is restricted by the annular element 1. Due to this increase in circumferential flow velocity, the flow velocity deviation in the circumferential direction is reduced. Consequently, the powder, including the fine powder, which is introduced into the interior of the frame body 41 by the vanes 48, is guided uniformly to each of the powder outlets 45 by the increased circumferential flow.

[0046] The result of a classification test of coal dust by the rotary separator 33 of the present embodiment is described. Fig. Figure 4 is a graph representing the flow velocity deviation of the coal dust released from the powder outlets at the time of classification.

[0047] In this classification test, a vertical mill was prepared in a state with a 9% deviation, using a rotary separator equipped with the annular element 1 serving as the constricting section described above, and a rotary separator without an annular element 1 serving as the constricting section described above. The powder flow deviation, including fine powder, was determined by calculating the total weight of fine powder discharged from the outlet openings through each of the four powder outlets in each rotary separator.

[0048] In Fig. Numbers 1 to 4 correspond to the four powder outlets located in the direction of rotation of the rotary separator. Fig. 4. Black sections correspond to the state before adjustment by the movable blade 49 with a deviation of 9%. White sections correspond to the state after adjustment by the movable blade 49, i.e., the rotary separator not provided with the annular element 1, which serves as the narrowing section described above. Sections with slanted lines correspond to the state after adjustment by the movable blade 49, i.e., the rotary separator provided with the annular element 1, which serves as the narrowing section described above. As in Fig. As shown in Figure 4, the deviation could be reduced (adjusted) to 1.1% by means of the rotary separator, which is provided with the annular element 1, which serves as the narrowing section described above.

[0049] In this way, the rotary separator (rotary classifier) ​​33 of the present embodiment comprises the following: the rotating shaft 40, which is supported rotating about the vertically extending axis of rotation C; the frame body 41, which is supported by the rotating shaft 40 and includes an opening 47 on the outer circumferential section of the frame body 41; a plurality of powder outlets 45, which are provided opening on the upper section of the frame body 41; a plurality of vanes 48, which are provided extending vertically at the opening 47 on the outer circumferential section of the frame body 41 along the direction of rotation; and the annular element 1, which serves as the narrowing section, which is provided such that the distance from the vanes 48 to the rotating shaft 40 is reduced.

[0050] According to this rotary separator 33, the circulating flow velocity is increased by maintaining torque when an upward flow, which passes upwards inside the frame body 41 due to a circulating flow caused by the rotation and movement of the vanes 48, is drawn inwards in a section bounded by the annular element 1. This increase in the circulating flow velocity reduces the flow velocity deviation in the circumferential direction. Consequently, the uniform distribution of powder discharged to the outside of the frame body 41 can be improved at each of the powder outlets 45.Furthermore, the present embodiment can improve the inhibiting effect of the particle in the movable blade 49 by means of the annular element 1 with respect to the configuration in which the movable blade 49 is positioned towards the rear of each of the powder outlets 45, and the uniform distribution of the powder can be improved by the inhibiting effect of the movable blade 49. Therefore, a uniform distribution of the coal dust quantity can be further improved.

[0051] Fig. 5, Fig. 6 to Fig. Figure 7 shows side cross-sectional views of another example of the rotary classifier according to the present embodiment. Fig. 5, Fig. 6 to Fig. Figure 7 shows a right half-section and the left half-section is not shown, because the configuration is symmetrical with a rotation axis C as a reference.

[0052] As in Fig. As shown in Figure 5, the annular element 1, which serves as the narrowing section described above, has in the lower section of the rotary separator 33, which serves as the rotary classifier of the present embodiment, an inclined surface 1c which extends upwards from the vane 48 side to the rotating shaft 40 side. Fig. 5 The inclined surface 1c is formed by a plate-shaped, annular element 1, which is inclined upwards from the wing 48 side to the rotating shaft 40 side. The inclined surface 1c has a flat shape in cross-section over the entire area from the wing 48 side to the rotating shaft 40 side of the annular element 1.

[0053] Although not shown, it is possible that the inclined surface 1c does not extend over the entire area from the wing 48 side to the rotating shaft 40 side of the annular element 1. For example, the wing 48 side and the rotating shaft 40 side may be partially inclined. Although not shown, the inclined surface 1c is not limited to a flat shape and may be formed in a curved cross-section such that a tangent from the wing 48 side to the rotating shaft 40 side is gradually directed upwards and approaches a perpendicular. Although not shown, the inclined surface 1c may be formed such that only a lower section of the annular element 1 is inclined.

[0054] According to this rotary separator 33, an upward flow, which rises inside the frame body 41 due to a circulating flow caused by the rotation and movement of the vanes 48, is corrected by the inclined surface 1c of the annular element 1. Therefore, drift, in which the flow velocity distribution of the powder deviates in an interior region of the frame body 41, is further reduced. Consequently, a significant improvement in the uniform distribution of the powder discharged to the outside of the frame body 41 can be achieved at each of the powder outlets 45.

[0055] In order to preferably achieve the corrective effect of the upward flow, the angle θ1 of the inclined surface 1c with respect to the horizontal surface is preferably in a range between -50 degrees and 50 degrees.

[0056] As in Fig. Figure 6, in the configuration in which the annular element 1, serving as the narrowing section described above, is provided, the rotary separator 33, as the rotary classifier of the present embodiment, comprises the following: a lower part 2, which extends upwards from the outer circumferential side of the inner base of the frame body 41 to the side of the rotating shaft 40 and has a surface 2a inclined continuously in the direction of rotation. Fig. 6 the inclined surface 2a is provided in a flat shape in a cross-section in the entire area from a lower end side of the wings 48 to the rotating shaft 40.

[0057] Although not shown, it is possible that the inclined surface 2a does not extend over the entire area from the lower end of the wings 48 to the rotating shaft 40. For example, the lower end of the wings 48 and the side of the rotating shaft 40 may be partially inclined. Although not shown, the inclined surface 2a is not limited to a flat shape and may be formed in a curved cross-section such that a tangent from the lower end of the wings 48 to the rotating shaft 40 is gradually directed upwards and approaches a perpendicular.

[0058] According to this rotary separator 33, an upward flow, which rises inside the frame body 41 due to a circulating flow caused by the rotation and movement of the vanes 48, is corrected by the inclined surface 2a of the lower part 2. Therefore, drift, in which the flow velocity distribution of the powder deviates in an interior region of the frame body 41, is further reduced. Consequently, through synergy with the action of the annular element 1, a significant improvement in the uniform distribution of the powder discharged to the outside of the frame body 41 can be achieved at each of the powder outlets 45.

[0059] If the inclined surface 1c described above is provided with the annular element 1, a significant improvement in the uniform distribution emitted to the outside of the rotary separator 33 in each of the powder outlets 45 can be achieved through synergy with the action of the annular element 1.

[0060] In order to preferably achieve the corrective effect of the upward flow, the angle θ2 of the inclined surface 2a with respect to the horizontal surface is preferably in a range between 20 degrees and 60 degrees.

[0061] As in Fig. As shown in Figure 7, in the rotary separator 33, which serves as the rotary classifier of a non-inventive example to illustrate aspects of the invention, the narrowing section comprises a convex part 3, which is provided continuously in the direction of rotation and projects from the rotating shaft 40 side to the vane 48 side, such that the distance of the vane 48 side from the vanes 48 to the rotating shaft 40 is narrowed.

[0062] The convex part 3 is supported by the pivot shaft 40 and is positioned between the upper support frame 42 and the lower support frame 43. The projection of the convex part 3 from the pivot shaft 40 terminates at a point inside the frame body 41, adjacent to the wings 48. Accordingly, the convex part 3, acting as the narrowing section, is designed to reduce the distance S3 from the inner edge of the wings 48 to the pivot shaft 40 to a distance S4 from the inner edge of the wings 48 to the end cap 3a by means of a specific position of the end cap 3a, and to limit the clearance between the upper support frame 42 and the lower support frame 43 within the frame body 41. The distance S4 is a distance of the wings 48 from the inner edge with respect to the horizontal position, which uses as a reference the position where the convex part 3 projects most prominently on the wing 48 side. As shown in Fig. As shown in Figure 7, if a position in which the convex part 3 protrudes most on the wing 48 side is parallel to the axis of rotation C, the horizontal position which has the lowest side position as a reference is defined as a distance of the wing 48 from the inner edge.

[0063] According to this rotary separator 33, the circulating flow velocity is increased by maintaining torque when the upward flow, which rises inside a frame body 41 due to a circulating flow caused by the rotation and movement of the vanes 48, flows through a section bounded by the convex part 3. This increase in the circulating flow velocity reduces the flow velocity deviation in the circumferential direction. Consequently, the uniform distribution of powder discharged to the outside of the frame body 41 at each of the powder outlets 45 can be improved.Furthermore, the present example can improve the inhibiting effect of the particle in the movable blade 49 by the convex part 3 with respect to the configuration in which the movable blade 49 is positioned towards the rear of each of the powder outlets 45, and a uniform distribution of the powder is achieved by the inhibiting effect of the movable blade 49. Therefore, a uniform distribution of the coal dust quantity can be further improved.

[0064] The position of the end 3a of the convex part 3 is preferably such that it does not connect with all openings under the powder outlets 45 in order not to impede the distribution of the powder flow when the powder is discharged from the powder outlets 45 to the outlet opening 32.

[0065] The convex part 3 has an inclined surface 3b, which extends upwards from the rotating shaft 40 side to the wing 48 side in a lower section of the convex part 3. Fig. 7 the inclined surface 3b is provided in a flat shape in a cross-section in the entire area from a lower end side of the rotating shaft 40 to the end end 3a inside the frame body 41.

[0066] Although not shown, it is possible that the inclined surface 3b does not extend over the entire area from the lower end of the rotating shaft 40 to the end 3a inside the frame body 41, and may be partially inclined. Although not shown, the inclined surface 3b is not limited to a flat shape and may be formed in a curved cross-section such that a tangent from the lower end of the rotating shaft 40 to the end 3a inside the frame body 41 is gradually directed upwards and approaches a perpendicular.

[0067] According to this rotary separator 33, the upward flow rising inside the frame body 41 due to the circulating flow caused by the rotation and movement of the vanes 48 is corrected by the inclined surface 3b of the convex part 3. Therefore, drift, in which the flow velocity distribution of the powder deviates in an interior region of the frame body 41, is further reduced. Consequently, a significant improvement in the uniform distribution of the powder discharged to the outside of the frame body 41 can be achieved at each of the powder outlets 45.

[0068] In a configuration where the movable paddle 49 is provided corresponding to each of the powder outlets 45, the rotary separator 33, which serves as the rotary classifier of the embodiment described above, reduces drift, in which the flow velocity distribution of the powder is deflected in an inner region of the frame body 41. This allows for a significantly improved, more uniform distribution of the powder discharged to the outside of the frame body 41 at each of the powder outlets 45.

[0069] A vertical mill of the present invention comprises the following: a hollow housing 11, a mill table 13 which is provided in a lower section of the housing 11 and is rotated about an axis of rotation along a vertical direction, mill rollers 18 which are provided opposite an upper surface of the mill table 13 and are rotatably supported, and the rotary separator (rotary classifier) ​​33 described above, which is provided in an upper section of the housing 11.

[0070] According to this vertical mill, a uniform distribution of powder discharged to the outside of the frame body at each of the powder outlets 45 can be improved by including a constricting section in the rotary separator 33. Therefore, when a solid material, such as coal (raw coal) or biomass, is pulverized, coal dust can be conveyed uniformly to a combustion plant. Furthermore, according to this vertical mill, a variation in the amount of coal dust discharged from each of the powder outlets can be achieved by means of the constricting section. List of reference symbols 1 Ring-shaped element 1a Outer edge 1b Inner edge 1c Inclined surface 2 lower part 2a Inclined surface 3 Convex part 3a End of final proceedings 3b Inclined surface 11 cases 13 Mill table 18 mill roller 33 Rotary separators (rotary classifiers) 40 Rotary shaft 41 frame bodies 42 Upper support frame 43 Lower support frame 44 Support part 45 Powder outlet 47 Opening 48 wings 49 Movable shovel 49a wave C axis of rotation

Claims

[1] Rotation classifier (33), comprising: a rotating shaft (40) which is supported around a rotation axis (C) extending in a vertical direction for rotation in one direction; a frame body (41) which is supported by the rotating shaft (40) and includes an opening (47) on an outer circumference of the frame body (41); a plurality of powder outlets (45) which are provided along the direction of rotation and open in an upper section of the frame body (41); a plurality of wings (48) extending vertically at the opening (47) on the outer circumference of the frame body (41) and provided along the direction of rotation; a narrowing section designed in such a way as to reduce the distance from the wings (48) to the rotating shaft (40), wherein the narrowing section comprises an annular element (1) which is provided continuously in the direction of rotation and extends from the side of the wings (48) to the side of the rotating shaft (40) such that the distance of the side of the rotating shaft (40) from the wings (48) to the rotating shaft (40) is narrowed, and wherein the annular element (1) is provided inside the frame body (41) from the wings (48). [2] Rotation classifier (33) according to claim 1, wherein the annular element (1) comprises an inclined surface (1c) which is formed upwards from the side of the wings (48) to the side of the rotating shaft (40) in a lower section. [3] Rotation classifier (33) according to claim 2, wherein an angle (θ1) of the inclined surface (1c) of the annular element (1) is set in relation to a horizontal plane in a range between -50 degrees and 50 degrees. [4] Rotary classifier (33) according to one of claims 1 to 3, further comprising a lower part (2) which extends upwards from an outer circumferential side of an inner base of the frame body (41) to the side of the rotating shaft (40) and comprises a surface (2a) inclined continuously in the direction of rotation. [5] Rotation classifier (33) according to claim 4, wherein an angle (θ2) of the inclined surface (2a) of the lower part (2) is set in relation to the horizontal plane in a range between 20 degrees and 60 degrees. [6] Vertical mill, including: a hollow casing (11); a mill table (13) which is provided in a lower section in the housing (11) and is rotatable about an axis of rotation along a vertical direction; Mill rollers (18) which are provided opposite a circumferential surface on an upper surface of the mill table (13) and are rotatably supported; and the rotary classifier (33) according to one of claims 1 to 5, which is provided in an upper section in the housing (11).

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