Vertical Mill

Abstract

Efficiently expels foreign matter. [Solution] The vertical mill comprises an annular first dam ring made up of a plurality of arc-shaped first plates (310) arranged along the outer periphery of the grinding table, and a diameter adjustment mechanism configured to move the plurality of first plates in the radial direction of the grinding table. The first dam ring is configured so that a portion of one first plate overlaps a portion of a first plate adjacent to the first first plate in the radial direction of the grinding table. The first plates include a first groove portion (340), a first protrusion portion (350), and a through hole (360) provided in the overlapping portion with the adjacent first plate, and the first protrusion portion of one first plate is configured to be engageable with the first groove portion of the first plate adjacent to the first first plate. When the plurality of first plates are moved by the diameter adjustment mechanism, the plurality of first plates slide in the circumferential direction, adjusting the diameter of the first dam ring and the opening area of ​​the through hole.

Description

[Technical Field]

[0001] The present disclosure relates to a vertical mill. [Background technology]

[0002] Vertical mills are widely used to pulverize materials such as coal, biomass, and cement raw materials. Vertical mills include a grinding table, grinding rollers, and an airflow generating unit. In vertical mills, the material is fed between the grinding table and the grinding rollers. The material is then crushed by the grinding rollers on the grinding table and pulverized. Furthermore, in vertical mills, the airflow generating unit generates an ascending airflow from the grinding table toward the discharge port. The pulverized material then rides the ascending airflow, moving from the grinding table to the discharge port and being discharged out of the vertical mill through the discharge port.

[0003] Furthermore, for the purpose of improving the grinding efficiency, a vertical mill equipped with a dam ring on the outer peripheral edge of the grinding table has been developed, as shown in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-175565 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned materials to be crushed may contain metallic foreign matter. Metallic foreign matter has a higher density than the materials to be crushed. For this reason, metallic foreign matter is difficult to transport by the rising air current, and there is a problem that metallic foreign matter accumulates on the crushing table.

[0006] In view of the above problems, the present disclosure aims to provide a vertical mill that can efficiently discharge foreign matter. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, a vertical mill according to one embodiment of the present disclosure includes a circular grinding table, a first dam ring having an annular shape and consisting of a plurality of arc-shaped first plates and arranged along the outer periphery of the grinding table, and a diameter adjustment mechanism configured to be able to move the plurality of first plates in a radial direction of the grinding table, wherein the first dam ring is configured so that a portion of one first plate overlaps a portion of a first plate adjacent to the one first plate in the radial direction of the grinding table, and the first plate is provided on one of the outer periphery and the inner periphery of the first plate body in an overlapping portion with the adjacent first plate, the first plate having an outer periphery and an inner periphery, and the first dam ring extends from one end of the first plate body toward the other end thereof. The first groove portion extends in the circumferential direction of the dam ring, and a first protrusion portion is provided on the other of the outer peripheral surface and inner peripheral surface of the first plate body in the overlapping portion with an adjacent first plate, extending in the circumferential direction of the first dam ring from the other end of the first plate body toward one end, and a through hole is provided in the overlapping portion with an adjacent first plate, penetrating the first plate body in the radial direction and extending in the circumferential direction of the first dam ring, wherein the first protrusion portion of one first plate is configured to be able to engage with the first groove portion of the adjacent first plate, and when the plurality of first plates are moved in the radial direction of the grinding table by the diameter adjustment mechanism, the plurality of first plates slide in the circumferential direction, adjusting the diameter of the first dam ring and the opening area of ​​the through hole.

[0008] The grinding table further includes a second dam ring of an annular shape made up of a plurality of arc-shaped second plates and provided along the inner periphery of the first dam ring, and a height adjustment mechanism configured to be able to adjust the position of the second dam ring in the height direction relative to the first dam ring, and the second dam ring is configured so that a part of one second plate and a part of a second plate adjacent to the first second plate overlap in the radial direction of the grinding table, and the second plate is provided on one of the outer periphery and inner periphery of the second plate body among the overlapping parts with the adjacent second plate, and extends from one end of the second plate body to the other end. The second dam ring may include a second groove portion extending in the circumferential direction of the second dam ring, and a second protrusion portion provided on the other of the outer peripheral surface and inner peripheral surface of the second plate body in the overlapping portion with the adjacent second plate, extending in the circumferential direction of the second dam ring from the other end of the second plate body toward the one end, wherein the second protrusion portion of one second plate is configured to be able to engage with the second groove portion of the adjacent second plate, and when the plurality of first plates are moved in the radial direction of the grinding table by the diameter adjustment mechanism, the plurality of first plates and the plurality of second plates slide in the circumferential direction, thereby adjusting the diameter of the first dam ring and the diameter of the second dam ring.

[0009] The first groove portion may be provided on the outer peripheral surface of the first plate body, and the first protrusion portion may be provided on the inner peripheral surface of the first plate body.

[0010] The second groove portion may be provided on the outer peripheral surface of the second plate body, and the second protrusion portion may be provided on the inner peripheral surface of the second plate body.

[0011] The diameter of the first dam ring may be adjusted based on the content of foreign matter contained in the material to be crushed.

[0012] The diameter of the first dam ring may be adjusted based on the crushing rate of the material to be crushed. [Effects of the Invention]

[0013] According to the present disclosure, foreign matter can be efficiently discharged. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a vertical mill according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram showing a first dam ring according to the embodiment installed at a first position. [Figure 3] FIG. 3 is a diagram showing a case where the first dam ring according to the embodiment is installed at a second position. [Figure 4] FIG. 4 is a top view of the dam ring unit in a first position. [Figure 5] FIG. 5 is a top view of the dam ring unit in the second position. [Figure 6] FIG. 6 is a top view of the first plate according to the embodiment. [Figure 7] FIG. 7 is a perspective view of the first plate according to the embodiment. [Figure 8] FIG. 8 is a top view of the second plate according to the same embodiment. [Figure 9] FIG. 9 is a perspective view of the second plate according to the same embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation. Elements not directly related to the present disclosure are not shown.

[0016] [1. Overview of vertical mill] First, referring to FIG. 1, an overview of a vertical mill 100 according to an embodiment of the present disclosure will be described. FIG. 1 is a schematic diagram of a vertical mill 100 according to this embodiment. In FIG. 1, solid arrows indicate the flow of the material to be ground and the gas-solid two-phase flow. Also, in FIG. 1, dashed arrows indicate the flow of gas. Note that in the following figures, including FIG. 1 of this embodiment, the X-axis, Y-axis, and Z-axis, which intersect perpendicularly, are defined as shown. Note that the X-axis and Y-axis indicate the horizontal direction, and the Z-axis indicates the vertical direction.

[0017] 1, the vertical mill 100 according to this embodiment includes, for example, a housing 110, a grinding table 120, one or more roller units 130, one or more pressure devices 140, a supply pipe 150, an outlet 160, an outlet 170, an airflow forming section 180, a rotary classifier 190, and a dam ring unit 200. For ease of understanding, only one roller unit 130 and one pressure device 140 are shown in FIG. 1, and the other roller units 130 and pressure devices 140 are omitted.

[0018] The housing 110 has a cylindrical shape. The housing 110 has, for example, a substantially cylindrical shape. The housing 110 is provided such that the axial direction of the housing 110 is aligned vertically or substantially vertically.

[0019] The housing 110 includes a main body 112 and a distribution section 114. The inner diameter of the main body 112 is approximately constant along the vertical direction. The distribution section 114 is connected to the upper part of the main body 112. The inner diameter of the distribution section 114 gradually increases from the bottom to the top. In other words, the flow path cross-sectional area of ​​the distribution section 114 gradually increases from the bottom to the top. Note that a communication point 116 between the main body 112 and the distribution section 114 is smaller than the inner diameter of the main body 112, for example.

[0020] The grinding table 120 is provided within the housing 110. The horizontal cross section of the grinding table 120 is circular. The grinding table 120 is, for example, disk-shaped. The grinding table 120 is provided within the housing 110 so that its rotation axis is vertical. The grinding table 120 is rotated by a table drive motor 124 via a reducer 122. The grinding table 120 is rotated by the table drive motor 124 at a constant speed or a variable speed.

[0021] A groove 126 is formed on the upper surface of the rotary table 120. The groove 126 is an annular groove centered on the rotation axis of the rotary table 120. A vertical cross section of the groove 126 passing through the rotation axis of the rotary table 120 is arc-shaped.

[0022] One or more roller units 130 are provided. For example, three roller units 130 are provided. The roller unit 130 includes a crushing roller 132, a roller shaft 134, a bracket 136, and a pivot shaft 138. The crushing roller 132 is provided above the crushing table 120 inside the housing 110. The crushing roller 132 is arranged, for example, inclined above the groove 126 of the crushing table 120. The more material to be crushed that is guided into the groove 126, the smaller the inclination of the crushing roller 132 becomes (approaching horizontal), and the fewer material to be crushed that is guided into the groove 126, the greater the inclination of the crushing roller 132 becomes.

[0023] The surface of the crushing roller 132 is, for example, a smooth surface. However, there are no limitations on the surface shape of the crushing roller 132. For example, the crushing roller 132 may have one or more holes (for example, dimples) formed therein, or one or more grooves formed therein. Furthermore, for example, the crushing roller 132 may have one or more protrusions formed therein.

[0024] In this embodiment, three crushing rollers 132 are provided radially at 120° intervals from the rotation center of the crushing table 120. The crushing rollers 132 are supported by bearings (not shown) attached to roller shafts 134. The roller shafts 134 are inserted into a bracket 136. In addition to the roller shafts 134, a pivot shaft 138 is inserted into the bracket 136. The pivot shaft 138 is supported by bearings (not shown).

[0025] One pressure device 140 is provided for each roller unit 130. In this embodiment, the vertical mill 100 has three roller units 130, and therefore three pressure devices 140 are provided. The pressure device 140 includes an actuator. The actuator is, for example, a hydraulic cylinder. The pressure device 140 presses the grinding roller 132 toward the grinding table 120. In this embodiment, the pressure device 140 presses the receiving seat 136a formed on the bracket 136. This causes a load to act on the receiving seat 136a. This causes the bracket 136 to swing around the pivot shaft 138 as the center of rotation. The grinding roller 132 swings together with the bracket 136 and is pressed downward toward the grinding table 120.

[0026] The supply pipe 150 is cylindrical. The supply pipe 150 is inserted into the upper wall 118 of the housing 110 so that its axial direction is vertical or approximately vertical. In this embodiment, the supply pipe 150 is inserted into the housing 110 so as to be coaxial with the housing 110. Also, in this embodiment, the supply pipe 150 is inserted into the housing 110 so as to be coaxial with the rotation axis of the grinding table 120. An upper opening of the supply pipe 150 is located outside the housing 110. A lower opening of the supply pipe 150 faces the grinding table 120 provided inside the housing 110. A not-shown material supplying device is connected to the upper opening of the supply pipe 150. The material to be ground is supplied onto the grinding table 120 by the material supplying device through the supply pipe 150.

[0027] The material to be crushed is, for example, solid fuel such as coal or biomass pellets. The biomass is, for example, one or more of woody biomass, herbaceous biomass, and waste-based biomass. Woody biomass is, for example, wood, sawdust, bark, etc. Herbaceous (plant) biomass is, for example, sugarcane, sorghum, bamboo, wheat straw, rice straw, etc. Waste-based biomass is, for example, empty fruit bunches (EFBs) and palm kernel shells (PKSs) that are generated as a result of producing palm oil from palm trees.

[0028] The discharge port 160 is formed above the grinding roller 132 in the housing 110. The discharge port 160 is formed, for example, in the upper wall 118 of the housing 110. Therefore, the distributor 114 is provided between the grinding roller 132 and the discharge port 160. In this embodiment, the vertical mill 100 is equipped with a plurality of discharge ports 160. The plurality of discharge ports 160 are formed in the upper wall 118 of the housing 110 at approximately equal intervals along the circumferential direction of the housing 110. A discharge pipe 162 is connected to the discharge port 160. The discharge pipe 162 discharges the material to be ground by the grinding table 120 and the grinding roller 132 to the outside. The discharge pipe 162 is connected, for example, to a combustion port of a furnace that constitutes a power generation device.

[0029] The air outlets 170 are provided on the outer edge or outside the outer edge of the grinding table 120. In this embodiment, the vertical mill 100 is equipped with a plurality of air outlets 170. The plurality of air outlets 170 are provided outside the outer edge of the grinding table 120 and are formed at approximately equal intervals along the outer edge of the grinding table 120.

[0030] The airflow forming unit 180 forms an airflow from the air outlet 170 toward the exhaust port 160 within the housing 110. That is, the airflow forming unit 180 forms an ascending air current within the housing 110. The airflow forming unit 180 includes, for example, a blower that supplies gas to the air outlet 170. The gas supplied by the airflow forming unit 180 is, for example, air, combustion exhaust gas, or nitrogen. Note that the configuration of the airflow forming unit 180 is not limited as long as it can form an airflow from the air outlet 170 toward the exhaust port 160 within the housing 110. The airflow forming unit 180 may include, for example, a blower that sucks gas from the exhaust port 160 instead of or in addition to the blower that supplies gas to the air outlet 170 described above.

[0031] In this embodiment, the vertical mill 100 may also include a rotary classifier 190. The rotary classifier 190 is provided within the main body 112 of the housing 110. The rotary classifier 190 includes, for example, a rotary rotor 192 and a plurality of blades 194. The rotary rotor 192 is an annular member provided to surround the outer periphery of the supply pipe 150. The plurality of blades 194 are provided at approximately equal intervals in the circumferential direction of the rotary rotor 192. The rotary rotor 192 is rotated by a driving device (not shown). The rotation of the rotary rotor 192 rotates the plurality of blades 194. Note that, as will be described in detail later, in this embodiment, the rotation of the rotary rotor 192 may be stopped. Furthermore, the plurality of blades 194 may be removed.

[0032] The dam ring unit 200 is provided along the outer periphery of the grinding table 120. As described above, the grinding table 120 is rotated by the table drive motor 124. Therefore, the dam ring unit 200 rotates in conjunction with the rotation of the grinding table 120. This prevents uneven wear of the dam ring unit 200 due to the objects to be ground on the grinding table 120. Details of the dam ring unit 200 will be described later.

[0033] [2. Operation of vertical mill] Next, the operation of the vertical mill 100 according to this embodiment will be described with reference to Fig. 1. First, the material to be crushed is supplied onto the crushing table 120 through the supply pipe 150 by the material to be crushed supply device.

[0034] The material to be crushed supplied to the crushing table 120 is caught between the recessed groove 126 of the crushing table 120 and the crushing roller 132. As the crushing table 120 rotates, the caught material to be crushed is crushed by the crushing roller 132 and crushed.

[0035] The pulverized material then rises within the main body 112 of the housing 110 together with the gas blown out through the outlet 170 by the airflow forming section 180. In other words, the pulverized material rises within the main body 112 of the housing 110 in a solid-gas two-phase flow state. The material then passes through the rotary classifier 190 and is transported by airflow to the distributor 114 of the housing 110.

[0036] As described above, the inner diameter of the distribution section 114 gradually increases from bottom to top. Therefore, the flow rate of the gas-solid two-phase flow transported to the distribution section 114 gradually decreases from bottom to top. This allows a vortex to be formed within the distribution section 114. The material to be pulverized is then efficiently dispersed within the distribution section 114 by the vortex. Therefore, the material to be pulverized is distributed approximately uniformly to the multiple discharge ports 160. The material to be pulverized distributed to the multiple discharge ports 160 is then discharged to the outside through the discharge pipe 162.

[0037] [3. Dam Ring Unit] Next, the dam ring unit 200 according to this embodiment will be described in detail with reference to FIGS. 1 to 5. FIGS. 2 and 3 are partial enlarged views of FIG. 1. FIG. 2 shows a case where the first dam ring 210 according to this embodiment is installed in a first position. FIG. 3 shows a case where the first dam ring 210 according to this embodiment is installed in a second position. FIG. 4 is a top view of the dam ring unit 200 in the first position. FIG. 5 is a top view of the dam ring unit 200 in the second position. Note that in FIGS. 4 and 5, a portion of the dam ring unit 200 is omitted for ease of understanding.

[0038] As shown in FIGS. 2 to 5, the dam ring unit 200 according to this embodiment includes a first dam ring 210 and a diameter adjustment mechanism 220. The first dam ring 210 and the diameter adjustment mechanism 220 are arranged in a radially outward direction.

[0039] The dam ring unit 200 is provided on the outer periphery of the upper surface 120a of the grinding table 120.

[0040] The first dam ring 210 is an annular member provided along the outer periphery of the rotary table 120. The first dam ring 210 is a plate member that stands upward (in the +Z direction in FIGS. 2 and 3) from the upper surface 222c of the pedestal 222 of the diameter adjustment mechanism 220, which will be described later. The specific configuration of the first dam ring 210 will be described in detail later.

[0041] The diameter adjustment mechanism 220 is configured to adjust the diameter of the first dam ring 210. In this embodiment, the diameter adjustment mechanism 220 can move the first dam ring 210 between a first position shown in FIG. 2 and a second position shown in FIG. 3. The first position is a position of the first dam ring 210 where the diameter of the first dam ring 210 is maximum. The second position is a position of the first dam ring 210 where the diameter of the first dam ring 210 is minimum. As the diameter adjustment mechanism 220 moves the first dam ring 210 from the first position to the second position, the diameter of the first dam ring 210 gradually decreases, and the first dam ring 210 approaches the center of the milling table 120. In other words, as the diameter adjustment mechanism 220 moves the first dam ring 210 from the second position to the first position, the diameter of the first dam ring 210 gradually increases, and the first dam ring 210 moves away from the center of the milling table 120.

[0042] The diameter adjustment mechanism 220 includes, for example, a base 222 , an elongated hole 224 , a screw hole 226 , and a screw 228 .

[0043] The pedestal 222 is provided on the outer periphery of the upper surface 120a of the rotary table 120. The pedestal 222 is an annular plate member (see FIGS. 4 and 5). The pedestal 222 is formed to be movable in the radial direction of the rotary table 120 (the ±X directions in FIGS. 2 and 3). In the first position, the pedestal 222 is formed so that the outer periphery 222b of the pedestal 222 is flush with the outer periphery 120b of the rotary table 120. For example, the inclination angle of the outer periphery 222b of the pedestal 222 corresponds to the inclination angle of the outer periphery 120b of the rotary table 120.

[0044] The base 222 is made up of, for example, arc-shaped divided members 222a divided into a plurality of pieces in the circumferential direction of the rotary table 120 (see FIGS. 4 and 5). Although details are omitted, the divided members 222a are configured so that a portion of one divided member 222a overlaps a portion of a divided member 222a adjacent to the one divided member 222a in the radial direction of the rotary table 120, similar to the first plate 310 of the first dam ring 210 described below. The divided members 222a are configured so that no gaps are formed between adjacent divided members 222a at the first position, the second position, or a position between the first and second positions. In FIG. 4, the overlapping portions of the divided members 222a are omitted for ease of understanding.

[0045] In the following description, the phrase "no gap is formed" means that "no gap is formed" to the extent that the material to be crushed and foreign matter do not unintentionally flow out from the crushing table 120 to the outlet 170. Therefore, the phrase "no gap is formed" includes not only the case where no gap is formed at all, but also the case where a gap is formed to the extent that the material to be crushed and foreign matter do not unintentionally flow out.

[0046] 2 and 3, a first dam ring 210 is provided on an upper surface 222c of the pedestal 222. In this embodiment, the first dam ring 210 stands upright on the upper surface 222c of the pedestal 222. The upper surface 222c of the pedestal 222 is, for example, a substantially horizontal surface.

[0047] The elongated hole 224 is formed in the base 222. The elongated hole 224 penetrates the base 222. For example, the elongated hole 224 is provided for each divided member 222a that constitutes the base 222. The elongated hole 224 extends in the radial direction of the grinding table 120. The width of the elongated hole 224 (the length in the circumferential direction of the grinding table 120) is slightly larger than the shaft portion 228b of the screw 228 and smaller than the head portion 228a of the screw 228.

[0048] The screw holes 226 are formed in the upper surface 120a of the grinding table 120. The screw holes 226 are formed at positions corresponding to the elongated holes 224 of the base 222.

[0049] The screw 228 includes a head 228a and a shaft 228b. The shaft 228b of the screw 228 is formed so as to be able to be threaded into the screw hole 226.

[0050] The screws 228 are attached to the elongated holes 224 formed in the base 222. The number of screws 228 provided corresponds to the number of elongated holes 224. For example, if one elongated hole 224 is provided for each divided member 222a, the number of screws 228 provided will be the same as the number of divided members 222a.

[0051] By loosening the screws 228, the base 222 (first dam ring 210) becomes slidable in the radial direction of the milling table 120 between a first position and a second position relative to the milling table 120. Furthermore, with the base 222 (first dam ring 210) disposed at a desired position between the first position and the second position, the heads 228a of the screws 228 can be moved downward (in the -Z direction in FIGS. 2 and 3) the more deeply the screws 228 are screwed into the screw holes 226. Then, the screws 228 are screwed into the screw holes 226 until the base 222 is locked by the heads 228a of the screws 228. In this way, the base 222 (first dam ring 210) is fixed to the milling table 120 by the screws 228.

[0052] Furthermore, the dam ring unit 200 may include a second dam ring 230 and a height adjustment mechanism 240 in addition to the first dam ring 210 and the diameter adjustment mechanism 220 .

[0053] The second dam ring 230 is an annular member provided along the inner periphery of the first dam ring 210. An outer circumferential surface 230a of the second dam ring 230 abuts, for example, against the inner circumferential surface 210a of the first dam ring 210. The specific configuration of the second dam ring 230 will be described in detail later.

[0054] The height adjustment mechanism 240 is configured to be able to adjust the position of the second dam ring 230 in the height direction (±Z direction in FIGS. 2 and 3) relative to the first dam ring 210. In this embodiment, the height adjustment mechanism 240 allows the second dam ring 230 to move between a first height shown in FIG. 2 and a second height shown in FIG. 3. The first height is the position of the second dam ring 230 where the height of the second dam ring 230 is the highest. The second height is the position of the second dam ring 230 where the height of the second dam ring 230 is the lowest.

[0055] The height adjustment mechanism 240 includes, for example, an elongated hole 242 , a screw hole 244 , and a screw 246 .

[0056] The elongated holes 242 are formed in the first dam ring 210. The elongated holes 242 penetrate the first dam ring 210. For example, the elongated holes 242 are provided in each first plate 310 of the first dam ring 210, which will be described later. The elongated holes 242 extend in the vertical direction (the ±Z directions in FIGS. 2 and 3). The width of the elongated holes 242 (the length in the circumferential direction of the grinding table 120) is slightly larger than the shaft portion 246b of the screw 246 and smaller than the head portion 246a of the screw 246.

[0057] The screw holes 244 are formed in the outer peripheral surface 230a of the second dam ring 230. The screw holes 244 are formed at positions corresponding to the elongated holes 242 of the first dam ring 210.

[0058] The screw 246 includes a head 246a and a shaft 246b. The shaft 246b of the screw 246 is formed so as to be able to be threaded into the screw hole 244.

[0059] The screws 246 are attached to the elongated holes 242 formed in the first dam ring 210. The number of screws 246 provided corresponds to the number of elongated holes 242. For example, if one elongated hole 242 is provided for each first plate 310, the number of screws 246 provided is equal to the number of first plates 310.

[0060] By loosening the screws 246, the second dam ring 230 becomes slidable in the vertical direction between the first height and the second height. Furthermore, with the second dam ring 230 disposed at a desired height between the first height and the second height, the deeper the screws 246 are screwed into the screw holes 244, the more the heads 246a of the screws 246 can be moved toward the center of the milling table 120 (the +X direction in FIGS. 2 and 3). Then, the screws 246 are screwed into the screw holes 244 until the first dam ring 210 is locked by the heads 246a of the screws 246. In this way, the second dam ring 230 is fixed to the first dam ring 210 by the screws 246.

[0061] [3.1. First Dam Ring] Next, the first dam ring 210 according to this embodiment will be described in detail with reference to Figs. 2 to 7. Fig. 6 is a top view of the first plate 310 according to this embodiment. Fig. 6A shows the first plate 310 when it is in the second position. Fig. 6B shows the first plate 310 when it is in the first position. Fig. 7 is a perspective view of the first plate 310 according to this embodiment. Note that the elongated holes 242 are omitted in Fig. 7 for ease of understanding.

[0062] 4 to 6, the first dam ring 210 is made up of a plurality of arc-shaped first plates 310. For example, the first dam ring 210 is made up of eight first plates 310. The first dam ring 210 is configured so that a portion of one first plate 310 and a portion of a first plate 310 adjacent to the one first plate 310 overlap in the radial direction of the rotary table 120.

[0063] As shown in FIGS. 6 and 7, the first plate 310 includes a first plate body 320, a first groove portion 340, a first protrusion portion 350, and a through-hole 360.

[0064] The first plate body 320 has an upper surface 322 , a lower surface 324 , an outer circumferential surface 326 , an inner circumferential surface 328 , and end surfaces 330 , 332 .

[0065] The upper surface 322 of the first plate body 320 is the surface facing upward among the surfaces of the first plate body 320. The upper surface of the first dam ring 210 is formed by the upper surfaces 322 of all of the first plate bodies 320 that constitute the first dam ring 210.

[0066] The lower surface 324 of the first plate body 320 is the surface facing downward among the surfaces of the first plate body 320. The lower surface 324 of the first plate body 320 is fixed to the upper surface 222c of the pedestal 222 of the diameter adjustment mechanism 220. The lower surface of the first dam ring 210 is formed by the lower surfaces 324 of all of the first plate bodies 320 that constitute the first dam ring 210.

[0067] The outer peripheral surface 326 of the first plate body 320 is the surface of the first plate body 320 that faces the outside of the first dam ring 210. The outer peripheral surface of the first dam ring 210 is formed by the outer peripheral surfaces 326 of all the first plate bodies 320 that constitute the first dam ring 210.

[0068] The outer peripheral surface 326 of the first plate main body 320 is composed of a first outer peripheral surface 326a and a second outer peripheral surface 326b. The second outer peripheral surface 326b is located more inward of the first outer peripheral surface 326a with respect to the first dam ring 210. A stepped surface 334 is located between the first outer peripheral surface 326a and the second outer peripheral surface 326b, extending radially inward from the end of the first outer peripheral surface 326a. In other words, the stepped surface 334 causes the radial positions of the first outer peripheral surface 326a and the second outer peripheral surface 326b to differ. The second outer peripheral surface 326b extends in the circumferential direction of the first dam ring 210 from the end surface 330 of the first plate main body 320 to the stepped surface 334. The first outer peripheral surface 326a extends in the circumferential direction of the first dam ring 210 from the stepped surface 334 to the end surface 332 of the first plate main body 320.

[0069] The inner circumferential surface 328 of the first plate main body 320 is composed of a first inner circumferential surface 328a and a second inner circumferential surface 328b. The second inner circumferential surface 328b is located further outward from the first inner circumferential surface 328a with respect to the first dam ring 210. A stepped surface 336 is located between the first inner circumferential surface 328a and the second inner circumferential surface 328b, extending radially inward from the end of the first inner circumferential surface 328a. In other words, the stepped surface 336 causes the radial positions of the first inner circumferential surface 328a and the second inner circumferential surface 328b to differ. The second inner circumferential surface 328b extends in the circumferential direction of the first dam ring 210 from the end surface 332 of the first plate main body 320 to the stepped surface 336. The first inner peripheral surface 328 a extends in the circumferential direction of the first dam ring 210 from the stepped surface 336 of the first plate body 320 to the end surface 330 .

[0070] In this embodiment, the second outer peripheral surface 326b of one first plate 310 and the second inner peripheral surface 328b of the first plate 310 adjacent to that one first plate 310 are configured to overlap in the radial direction. The second outer peripheral surface 326b of one first plate 310 and the second inner peripheral surface 328b of the first plate 310 adjacent to that one first plate 310 are provided to be slidable relative to each other in the circumferential direction.

[0071] The first groove 340 is provided in one of the outer peripheral surface 326 (second outer peripheral surface 326b) and the inner peripheral surface 328 (second inner peripheral surface 328b) of the first plate main body 320 in the overlapping portion with the adjacent first plate 310. As shown in FIG. 7 , in this embodiment, the first groove 340 is provided in the second outer peripheral surface 326b of the first plate main body 320. The first groove 340 extends in the circumferential direction of the first dam ring 210 from one end to the other end of the first plate main body 320. More specifically, the first groove 340 extends in the circumferential direction of the first dam ring 210 from the end surface 330 of the first plate main body 320 toward the stepped surface 334.

[0072] The first protrusion 350 is provided on the other of the outer peripheral surface 326 (second outer peripheral surface 326b) and the inner peripheral surface 328 (second inner peripheral surface 328b) of the first plate main body 320 in the overlapping portion with the adjacent first plate 310. As shown in FIG. 7 , in this embodiment, the first protrusion 350 is provided on the second inner peripheral surface 328b of the first plate main body 320. The first protrusion 350 extends in the circumferential direction of the first dam ring 210 from the other end toward one end of the first plate main body 320. More specifically, the first protrusion 350 extends in the circumferential direction of the first dam ring 210 from the end surface 332 of the first plate main body 320 toward the stepped surface 336.

[0073] Furthermore, the first protrusion 350 of one first plate 310 is configured to be able to engage with the first groove 340 of the first plate 310 adjacent to that one first plate 310 .

[0074] For this reason, it is preferable that the vertical cross-sectional shape of the first protrusion 350 corresponds to the vertical cross-sectional shape of the first groove 340. For example, as shown in Fig. 7, when the vertical cross-sectional shape of the first groove 340 is triangular, the vertical cross-sectional shape of the first protrusion 350 is also triangular.

[0075] The vertical cross-sectional shape of the first groove 340 is not limited to a triangle. For example, the vertical cross-sectional shape of the first groove 340 may be a rectangle, a semicircle, a trapezoid, or the like. It is preferable that the vertical cross-sectional shape of the first groove 340 is such that the bottom surface of the first groove 340 (the surface on the inner circumferential surface 328 side of the first plate main body 320) is larger than the opening of the first groove 340. This allows the first groove 340 and the first protrusion 350 to slide in the first groove 340 while restricting the first protrusion 350 from moving (disengaging) from the first groove 340 in the radial direction of the first dam ring 210.

[0076] The through-hole 360 ​​is provided in an overlapping portion between adjacent first plates, penetrates the first plate main body 320 in the radial direction, and extends in the circumferential direction of the first dam ring 210. As described above, in this embodiment, the second outer peripheral surface 326b of one first plate 310 and the second inner peripheral surface 328b of the first plate 310 adjacent to that one first plate 310 are configured to overlap in the radial direction. Therefore, the through-hole 360 ​​is provided, for example, at a position where it penetrates the second outer peripheral surface 326b and the second inner peripheral surface 328b of the first plate main body 320. As will be described in detail later, the area of ​​the inlet of the through-hole 360 ​​(the opening on the second inner peripheral surface 328b side) is adjusted by sliding the multiple first plates 310 in the circumferential direction.

[0077] Furthermore, it is preferable that the through-holes 360 are provided in the lower part of the first plate body 320. This allows foreign matter (for example, metallic foreign matter) with a higher density than the material to be crushed to be efficiently discharged from the crushing table 120. The foreign matter discharged from the through-holes 360 falls into the space below through the air outlet 170. The foreign matter is then discharged from the space below to the outside by a discharge mechanism (not shown).

[0078] As shown in FIG. 6, the elongated hole 242 is formed in the first plate body 320 so as to connect the first outer peripheral surface 326a and the first inner peripheral surface 328a.

[0079] [3.2. Adjustment of the first dam ring using the diameter adjustment mechanism] The diameter adjustment mechanism 220 is configured to be able to move the multiple first plates 310 in the radial direction of the rotary table 120.

[0080] 6A , at the second position where the diameter of the first dam ring 210 is smallest, the stepped surface 334, the second outer peripheral surface 326b, and the end surface 330 of one first plate 310 abut against the end surface 332, the second inner peripheral surface 328b, and the stepped surface 336 of the first plate 310 adjacent to that first plate 310, respectively. Therefore, at the second position, no gap is formed between the first plate 310 and the first plate 310 adjacent to that first plate 310. Therefore, the first outer peripheral surfaces 326a of the multiple first plates 310 are flush with each other, and the first inner peripheral surfaces 328a of the multiple first plates 310 are flush with each other.

[0081] In addition, in the second position, the through-hole 360 ​​of one of the first plates 310 is closed by the second outer peripheral surface 326b of the first plate 310 adjacent to that one of the first plates 310.

[0082] Then, when the diameter adjustment mechanism 220 moves the multiple first plates 310 in the radial direction of the grinding table 120 from the second position to the first position, the multiple first plates 310 slide in the circumferential direction and reach the state shown in FIG. 6B. In detail, as shown in FIG. 6B, at the first position where the diameter of the first dam ring 210 is maximum, the step surface 334 and end surface 330 of one first plate 310 are separated from the end surface 332 and step surface 336 of the first plate 310 adjacent to that first plate 310, respectively. Furthermore, at the first position, the second outer peripheral surface 326b of one first plate 310 and the second inner peripheral surface 328b of the first plate 310 adjacent to that first plate 310 come into contact.

[0083] Furthermore, at the first position, the through-hole 360 ​​of one first plate 310 faces the gap between the step surface 336 of one first plate 310 and the end surface 330 of the first plate 310 adjacent to that one first plate 310. Therefore, at the first position, the through-hole 360 ​​communicates between the outside and inside of the first dam ring 210, i.e., the outside of the first dam ring 210 and the rotary table 120.

[0084] In this way, as one first plate 310 moves from the second position to the first position, the contact area between the second outer peripheral surface 326b of one first plate 310 and the second inner peripheral surface 328b of the first plate 310 adjacent to that one first plate 310 becomes smaller. In other words, as one first plate 310 moves from the second position to the first position, the area of ​​the through hole 360 ​​blocked by the second outer peripheral surface 326b becomes smaller, and the opening area of ​​the through hole 360 ​​gradually becomes larger. In other words, when the diameter adjustment mechanism 220 moves the multiple first plates 310 in the radial direction of the rotary table 120, the multiple first plates 310 slide in the circumferential direction, and the diameter of the first dam ring 210 and the opening area of ​​the through hole 360 ​​are adjusted.

[0085] [3.3. Second Dam Ring] Next, the second dam ring 230 according to this embodiment will be described in detail with reference to FIGS. 4 to 5 and 8 to 9. FIG. 8 is a top view of the second plate 410 according to this embodiment. FIG. 8A shows the second plate 410 when it is in the second position. FIG. 8B shows the second plate 410 when it is in the first position. FIG. 9 is a perspective view of the second plate 410 according to this embodiment. Note that the screw holes 244 are omitted in FIG. 9 for ease of understanding.

[0086] As shown in FIGS. 4 to 5, 8 and 9, the second dam ring 230 is made up of a plurality of arc-shaped second plates 410. For example, the second dam ring 230 is made up of the same number of second plates 410 (e.g., eight) as the number of first plates 310 constituting the first dam ring 210. In this embodiment, each of the plurality of second plates 410 is fixed to each of the plurality of first plates 310 by a screw 246. The second dam ring 230 is configured, like the first dam ring 210, so that a portion of one second plate 410 and a portion of a second plate 410 adjacent to that one second plate 410 overlap in the radial direction of the rotary table 120.

[0087] Furthermore, even when the multiple first plates 310 and the multiple second plates 410 are arranged at the second height (see Figure 3) where the height of the second dam ring 230 is the lowest, the second plates 410 are positioned so that the through holes 360 of the first plates 310 are not blocked by the second plates 410.

[0088] 8 and 9, the second plate 410 includes a second plate main body 420, a second groove portion 440, and a second protrusion portion 450. That is, the second plate 410 is similar to the first plate 310 except that the second plate 410 does not include a through-hole 360.

[0089] The second plate body 420 has an upper surface 422 , a lower surface 424 , an outer circumferential surface 426 , an inner circumferential surface 428 , and end surfaces 430 , 432 .

[0090] The upper surface 422 of the second plate body 420 is the surface facing upward among the surfaces of the second plate body 420. The upper surface of the second dam ring 230 is formed by the upper surfaces 422 of all the second plate bodies 420 that constitute the second dam ring 230.

[0091] The lower surface 424 of the second plate body 420 is the surface facing downward among the surfaces of the second plate body 420. The lower surface 424 of the second plate body 420 faces the upper surface 222c of the base 222 of the diameter adjustment mechanism 220. The lower surface of the second dam ring 230 is formed by the lower surfaces 424 of all the second plate bodies 420 that constitute the second dam ring 230.

[0092] The outer peripheral surface 426 of the second plate body 420 is the surface of the second plate body 420 that faces the outside of the second dam ring 230. At least a part of the outer peripheral surface 426 of the second plate body 420 comes into contact with the inner peripheral surface 328 of the first plate 310 (first plate body 320) of the first dam ring 210 so as to be slidable in the vertical direction. The outer peripheral surfaces 426 of all the second plate bodies 420 that constitute the second dam ring 230 form the outer peripheral surface 230a of the second dam ring 230.

[0093] The outer peripheral surface 426 of the second plate main body 420 is composed of a first outer peripheral surface 426a and a second outer peripheral surface 426b. The second outer peripheral surface 426b is located more inward of the first outer peripheral surface 426a with respect to the second dam ring 230. A stepped surface 434 is located between the first outer peripheral surface 426a and the second outer peripheral surface 426b, extending radially inward from the end of the first outer peripheral surface 426a. In other words, the stepped surface 434 causes the radial positions of the first outer peripheral surface 426a and the second outer peripheral surface 426b to differ. The second outer peripheral surface 426b extends in the circumferential direction of the second dam ring 230 from the end surface 430 of the second plate main body 420 to the stepped surface 434. The first outer peripheral surface 426a extends in the circumferential direction of the second dam ring 230 from the stepped surface 434 to the end surface 432 of the second plate main body 420. At least a portion of the first outer peripheral surface 426a of the second plate body 420 comes into vertically slidable contact with the first inner peripheral surface 328a of the inner peripheral surface 328 of the first plate 310 (first plate body 320) of the first dam ring 210.

[0094] The inner circumferential surface 428 of the second plate main body 420 is composed of a first inner circumferential surface 428a and a second inner circumferential surface 428b. The second inner circumferential surface 428b is located further outward from the first inner circumferential surface 428a than the second dam ring 230. A stepped surface 436 is located between the first inner circumferential surface 428a and the second inner circumferential surface 428b, extending radially inward from the end of the first inner circumferential surface 428a. In other words, the stepped surface 436 causes the radial positions of the first inner circumferential surface 428a and the second inner circumferential surface 428b to differ. The second inner circumferential surface 428b extends in the circumferential direction of the second dam ring 230 from the end surface 432 of the second plate main body 420 to the stepped surface 436. The first inner peripheral surface 428 a extends in the circumferential direction of the second dam ring 230 from the stepped surface 436 of the second plate body 420 to the end surface 430 .

[0095] In this embodiment, the second outer peripheral surface 426b of one second plate 410 and the second inner peripheral surface 428b of the second plate 410 adjacent to that one second plate 410 are configured to overlap in the radial direction. The second outer peripheral surface 426b of one second plate 410 and the second inner peripheral surface 428b of the second plate 410 adjacent to that one second plate 410 are provided to be slidable relative to each other in the circumferential direction.

[0096] The second groove 440 is provided in one of the outer peripheral surface 426 (second outer peripheral surface 426b) and the inner peripheral surface 428 (second inner peripheral surface 428b) of the second plate main body 420 in the overlapping portion with the adjacent second plate 410. As shown in FIG. 9 , in this embodiment, the second groove 440 is provided in the second outer peripheral surface 426b of the second plate main body 420. The second groove 440 extends in the circumferential direction of the second dam ring 230 from one end to the other end of the second plate main body 420. Specifically, the second groove 440 extends in the circumferential direction of the second dam ring 230 from the end surface 430 of the second plate main body 420 toward the stepped surface 434.

[0097] The second protrusion 450 is provided on the other of the outer peripheral surface 426 (second outer peripheral surface 426b) and the inner peripheral surface 428 (second inner peripheral surface 428b) of the second plate main body 420 in the overlapping portion with the adjacent second plate 410. As shown in FIG. 9 , in this embodiment, the second protrusion 450 is provided on the second inner peripheral surface 428b of the second plate main body 420. The second protrusion 450 extends in the circumferential direction of the second dam ring 230 from the other end toward one end of the second plate main body 420. More specifically, the second protrusion 450 extends in the circumferential direction of the second dam ring 230 from the end surface 432 of the second plate main body 420 toward the stepped surface 436.

[0098] Furthermore, the second protrusion 450 of one second plate 410 is configured to be able to engage with the second groove 440 of the second plate 410 adjacent to the one second plate 410 .

[0099] For this reason, it is preferable that the vertical cross-sectional shape of second protrusion 450 corresponds to the vertical cross-sectional shape of second groove 440. For example, as shown in Fig. 9, when the vertical cross-sectional shape of second groove 440 is triangular, the vertical cross-sectional shape of second protrusion 450 is also triangular.

[0100] As with the first groove 340, the vertical cross-sectional shape of the second groove 440 is not limited to a triangle. For example, the vertical cross-sectional shape of the second groove 440 may be a rectangle, a semicircle, a trapezoid, or the like. Preferably, the vertical cross-sectional shape of the second groove 440 is such that the bottom surface of the second groove 440 (the surface on the inner circumferential surface 428 side of the second plate main body 420) is larger than the opening of the second groove 440. This allows the second groove 440 and the second protrusion 450 to slide in the second groove 440 while restricting the second protrusion 450 from moving (disengaging) from the second groove 440 in the radial direction of the second dam ring 230.

[0101] 8, the screw holes 244 are formed in the second plate body 420 so that the first outer peripheral surface 426a and the first inner peripheral surface 428a are in communication with each other. The screw holes 244 are also provided at positions corresponding to the elongated holes 242 of the first plate body 320.

[0102] [3.4. Control of diameter adjustment mechanism and height adjustment mechanism] In this embodiment, the diameter of the first dam ring 210 may be adjusted by the diameter adjustment mechanism 220 based on the content of foreign matter contained in the material to be pulverized. For example, if the content of foreign matter contained in the material to be pulverized is high, the diameter of the first dam ring 210 is increased to increase the opening area of ​​the through holes 360. This allows the foreign matter to be efficiently discharged from the grinding table 120 through the through holes 360. Furthermore, for example, if the content of foreign matter contained in the material to be pulverized is low, the diameter of the first dam ring 210 is decreased to decrease the opening area of ​​the through holes 360. This prevents the material from being unnecessarily discharged from the grinding table 120 through the through holes 360. If the foreign matter is metallic, the material to be pulverized may be subjected to a magnetic separator before being supplied to the vertical mill 100, and the content of foreign matter contained in the material to be pulverized may be obtained based on the amount of material collected by the magnetic separator.

[0103] Furthermore, in this embodiment, the diameter of the first dam ring 210 may be adjusted by the diameter adjustment mechanism 220 based on the crushing rate of the material to be crushed. The crushing rate of the material to be crushed is the ratio of the amount of material to be crushed having a desired particle size or less produced by crushing to the amount of material to be crushed supplied into the housing 110 through the supply pipe 150. For example, the crushing rate of the material to be crushed can be determined by the mill differential pressure. The mill differential pressure is the difference between the air pressure before the material is supplied into the housing 110 from the outlet 170 and the air pressure inside the housing 110. When comparing the same supply amount of material to be crushed, the higher the mill differential pressure, the lower the crushing rate, and the lower the mill differential pressure, the higher the crushing rate.

[0104] In the vertical mill 100, the height of the second dam ring 230 required to achieve a desirable crushing rate varies depending on the type of material being crushed. Therefore, it is possible to adjust the height of the second dam ring 230 using the height adjustment mechanism 240 to achieve a desirable crushing rate. However, if the height of the second dam ring 230 is too high, there is a risk that it will collide with the bracket 136 of the roller unit 130. The bracket 136 slopes vertically downward as it approaches the center of the crushing table 120. Therefore, if there is a risk that the second dam ring 230 will collide with the bracket 136 of the roller unit 130, the diameter adjustment mechanism 220 first expands the diameter of the first dam ring 210 to a position where the second dam ring 230 will not collide with the bracket 136 of the roller unit 130. Then, the height adjustment mechanism 240 adjusts the height of the second dam ring 230 to achieve a desirable crushing rate. This makes it possible to prevent collision between the second dam ring 230 and the bracket 136 of the roller unit 130, while achieving a desirable crushing rate for the material to be crushed.

[0105] [4. Summary] As described above, the vertical mill 100 according to this embodiment includes a circular grinding table 120, an annular first dam ring 210 consisting of a plurality of arc-shaped first plates 310 and provided along the outer periphery of the grinding table 120, and a diameter adjustment mechanism 220 configured to be able to move the plurality of first plates 310 in the radial direction of the grinding table 120, the first dam ring 210 is configured so that a portion of one first plate 310 overlaps with a portion of a first plate 310 adjacent to the one first plate 310 in the radial direction of the grinding table 120, the first plate 310 is configured so that a first plate main body 320 having an outer circumferential surface 326 and an inner circumferential surface 328 overlaps with an adjacent first plate 310, and the first dam ring 210 is provided on one of the outer circumferential surface 326 and the inner circumferential surface 328 of the first plate main body 310 in the overlapping portion between the first plate 310 and the adjacent first plate 310, and the first dam ring 210 extends from one end of the first plate main body 320 toward the other end. The first dam ring 210 includes a first protrusion 350 that is provided on the other of the outer peripheral surface 326 and the inner peripheral surface 328 of the first plate main body 320, in the overlapping portion between the first groove 340 extending circumferentially of the ring 210 and an adjacent first plate 310, and that extends circumferentially of the first dam ring 210 from the other end of the first plate main body 320 toward one end of the first plate main body 320, and a through hole that is provided in the overlapping portion with the adjacent first plate 310, that penetrates the first plate main body 320 in the radial direction and extends circumferentially of the first dam ring 210, the first protrusion 350 of one first plate 310 is configured to be able to engage with the first groove 340 of the adjacent first plate 310, and when the diameter adjustment mechanism 220 moves the plurality of first plates 310 in the radial direction of the grinding table 120, the plurality of first plates 310 slide in the circumferential direction, and the diameter of the first dam ring 210 and the opening area of ​​the through hole 360 ​​are adjusted.

[0106] As described above, the vertical mill 100 according to this embodiment includes the first groove portion 340 and the first protrusion portion 350. Therefore, in the vertical mill 100 according to this embodiment, the diameter adjustment mechanism 220 moves the multiple first plates 310 in the radial direction of the grinding table 120, and when the multiple first plates 310 slide in the circumferential direction, it is possible to restrict the vertical movement of the multiple first plates 310. Therefore, the vertical mill 100 according to this embodiment allows the multiple first plates 310 to slide smoothly.

[0107] The vertical mill 100 according to this embodiment also includes a through hole 360. This allows the vertical mill 100 according to this embodiment to efficiently discharge foreign matter from the grinding table 120. This prevents wear and damage to the grinding table 120 and the grinding roller 132 due to foreign matter. As described above, in this embodiment, as the diameter of the first dam ring 210 increases, the opening area of ​​the through hole 360 ​​also increases. As the diameter of the first dam ring 210 increases, the amount of material to be ground on the grinding table 120 increases, resulting in a larger amount of foreign matter. Therefore, by increasing the diameter of the first dam ring 210, the opening area of ​​the through hole 360 ​​also increases. This allows the vertical mill 100 according to this embodiment to more efficiently discharge foreign matter from the grinding table 120.

[0108] The rotary table 120 further includes a second dam ring 230 made up of a plurality of arc-shaped second plates 410 and arranged along the inner periphery of the first dam ring 210, and a height adjustment mechanism 240 configured to be able to adjust the position of the second dam ring 230 in the height direction relative to the first dam ring 210, the second dam ring 230 is configured so that a portion of one second plate 410 and a portion of a second plate 410 adjacent to the one second plate 410 overlap in the radial direction of the rotary table 120, the second plate 410 is arranged on one of the outer circumferential surface 426 and the inner circumferential surface 428 of the second plate main body 420, of the overlapping portion between the second plate 410 and the adjacent second plate 410, and the second plate 410 extends from one end of the second plate main body 420 to the other end. The second dam ring 230 includes a second groove 440 extending circumferentially of the second dam ring 230, and a second protrusion 450 provided on the other of the outer peripheral surface 426 and the inner peripheral surface 428 of the second plate main body 420 in the overlapping portion with the adjacent second plate 410, and extending circumferentially of the second dam ring 230 from the other end of the second plate main body 420 to the one end, and the second protrusion 450 of one second plate 410 is configured to be able to engage with the second groove 440 of the adjacent second plate 410, and when the diameter adjustment mechanism 220 moves the plurality of first plates 310 in the radial direction of the grinding table 120, the plurality of first plates 310 and the plurality of second plates 410 slide circumferentially, and the diameters of the first dam ring 210 and the second dam ring 230 are adjusted.

[0109] As described above, in the vertical mill 100, the height of the second dam ring 230 required to achieve a desirable crushing rate varies depending on the type of material being crushed. The vertical mill 100 according to this embodiment is equipped with a height adjustment mechanism 240, which allows the height of the second dam ring 230 to be adjusted to suit the type of material being crushed. Therefore, the vertical mill 100 according to this embodiment can improve the crushing rate regardless of the type of material being crushed. Furthermore, as described above, if there is a risk that the second dam ring 230 will collide with the bracket 136 of the roller unit 130, the diameter adjustment mechanism 220 can first increase the diameter of the first dam ring 210 to a position where the second dam ring 230 will not collide with the bracket 136 of the roller unit 130. The height adjustment mechanism 240 can then adjust the height of the second dam ring 230 to achieve a crushing rate determined based on the type of material being crushed. This makes it possible to prevent collision between the second dam ring 230 and the bracket 136 of the roller unit 130, while achieving a desirable crushing rate for the material to be crushed.

[0110] Alternatively, the first groove portion 340 may be provided on the outer peripheral surface 326 of the first plate body 320 , and the first protrusion portion 350 may be provided on the inner peripheral surface 328 of the first plate body 320 .

[0111] As described above, the grinding table 120 is rotated by the table drive motor 124, and the first dam ring 210 is fixed to the grinding table 120 via the pedestal 222. Therefore, the first dam ring 210 rotates in conjunction with the rotation of the grinding table 120. As a result, centrifugal force is applied to the first dam ring 210. Therefore, by providing the first groove 340 on the outer peripheral surface 326 of the first plate body 320 and the first protrusion 350 on the inner peripheral surface 328 of the first plate body 320, it is possible to prevent the first protrusion 350 from fitting into the first groove 340 due to centrifugal force. Therefore, the vertical mill 100 according to this embodiment can prevent the first plates 310 from being unable or having difficulty moving relative to each other.

[0112] Alternatively, the second groove portion 440 may be provided on the outer peripheral surface 426 of the second plate main body 420 , and the second protrusion portion 450 may be provided on the inner peripheral surface 428 of the second plate main body 420 .

[0113] As described above, the grinding table 120 is rotated by the table drive motor 124, and the second dam ring 230 is fixed to the grinding table 120 via the base 222 and the first dam ring 210. Therefore, the second dam ring 230 rotates in conjunction with the rotation of the grinding table 120. This applies centrifugal force to the second dam ring 230. Therefore, by providing the second groove 440 on the outer peripheral surface 426 of the second plate body 420 and the second protrusion 450 on the inner peripheral surface 428 of the second plate body 420, it is possible to prevent the second protrusion 450 from fitting into the second groove 440 due to centrifugal force. Therefore, the vertical mill 100 according to this embodiment can prevent the second plates 410 from being unable or having difficulty moving relative to each other.

[0114] Furthermore, the diameter of the first dam ring 210 may be adjusted based on the content of foreign matter contained in the material to be pulverized. This allows the vertical mill 100 according to this embodiment to more efficiently discharge foreign matter from the grinding table 120.

[0115] The diameter of the first dam ring 210 may be adjusted based on the crushing rate of the material to be crushed. This allows the vertical mill 100 according to this embodiment to further improve the crushing rate of the material to be crushed.

[0116] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0117] For example, in the above embodiment, the through-hole 360 ​​is provided in the first dam ring 210. However, the through-hole 360 ​​may be provided in the base 222 of the diameter adjustment mechanism 220 in addition to the first dam ring 210. This allows foreign matter to be discharged more efficiently.

[0118] The diameter adjustment mechanism 220 may also include rails that reciprocate the divided members 222a that make up the base 222 in the radial direction of the grinding table 120. This makes it possible to appropriately adjust the diameter of the first dam ring 210 while maintaining an equal distance between adjacent divided members 222a.

[0119] This disclosure can contribute, for example, to Sustainable Development Goals (SDGs) Goal 7: "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13: "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0120] 100 Vertical Mill 120 Grinding Table 210 First Dam Ring 220 Diameter adjustment mechanism 230 Second Dam Ring 240 Height adjustment mechanism 310 First Plate 320 First plate body 326 Outer surface 328 Inner surface 340 First groove 350 1st protrusion 360 through hole 410 Second Plate 420 Second plate body 426 Outer surface 428 Inner surface 440 Second groove 450 2nd protrusion

Claims

1. A circular grinding table; a first dam ring having an annular shape and including a plurality of arc-shaped first plates and provided along the outer periphery of the grinding table; a diameter adjustment mechanism configured to be able to move the plurality of first plates in the radial direction of the rotary table; Equipped with The first dam ring is configured such that a portion of one of the first plates and a portion of the first plate adjacent to the one first plate overlap in the radial direction of the grinding table, The first plate is a first plate body having an outer peripheral surface and an inner peripheral surface; a first groove portion provided on one of the outer peripheral surface and the inner peripheral surface of the first plate body in the overlapping portion with the adjacent first plate, the first groove portion extending in the circumferential direction of the first dam ring from one end portion of the first plate body to the other end portion; a first protrusion provided on the other of the outer peripheral surface and the inner peripheral surface of the first plate body in the overlapping portion with the adjacent first plate, the first protrusion extending in a circumferential direction of the first dam ring from the other end portion toward the one end portion of the first plate body; a through hole provided at an overlapping portion between the adjacent first plates, penetrating the first plate body in a radial direction and extending in a circumferential direction of the first dam ring; Including, the first protrusion of the first plate is configured to be engageable with the first groove of the adjacent first plate, When the plurality of first plates are moved in the radial direction of the grinding table by the diameter adjustment mechanism, the plurality of first plates slide in the circumferential direction, thereby adjusting the diameter of the first dam ring and the opening area of ​​the through hole.

2. a second dam ring having an annular shape and including a plurality of arc-shaped second plates and provided along an inner periphery of the first dam ring; a height adjustment mechanism configured to adjust the position of the second dam ring relative to the first dam ring in a height direction; Equipped with The second dam ring is configured so that a portion of one of the second plates and a portion of the second plate adjacent to the first second plate overlap in the radial direction of the grinding table, The second plate is a second plate body having an outer peripheral surface and an inner peripheral surface; a second groove portion provided on one of the outer peripheral surface and the inner peripheral surface of the second plate body in the overlapping portion with the adjacent second plate, the second groove portion extending in the circumferential direction of the second dam ring from one end portion of the second plate body to the other end portion; a second protrusion provided on the other of the outer peripheral surface and the inner peripheral surface of the second plate body in the overlapping portion with the adjacent second plate, the second protrusion extending in the circumferential direction of the second dam ring from the other end portion toward the one end portion of the second plate body; Including, the second protrusion of the first second plate is configured to be engageable with the second groove of the adjacent second plate, 2. The vertical mill according to claim 1, wherein when the plurality of first plates are moved in the radial direction of the grinding table by the diameter adjustment mechanism, the plurality of first plates and the plurality of second plates slide in the circumferential direction, thereby adjusting the diameters of the first dam ring and the second dam ring.

3. the first groove portion is provided in the outer circumferential surface of the first plate body, The vertical mill according to claim 1 or 2, wherein the first protrusion is provided on the inner peripheral surface of the first plate body.

4. The second groove portion is provided in the outer circumferential surface of the second plate body, The vertical mill according to claim 2 , wherein the second protrusion is provided on the inner peripheral surface of the second plate body.

5. 3. The vertical mill according to claim 1, wherein the diameter of the first dam ring is adjusted based on the content of foreign matter contained in the material to be pulverized.

6. 3. The vertical mill according to claim 1, wherein the diameter of the first dam ring is adjusted based on the crushing rate of the material to be crushed.

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