The present disclosure relates to roller mill equipment and methods of retrofitting roller mill equipment. Background technology [0002] 　Roller mill equipment is used for fine grinding of coal, petroleum coke, etc., or pulverization of biomass raw materials, etc. in boilers and combined coal gasification combined power generation. It is also widely used in cement manufacturing plants for crushing cement materials and cement clinker. Roller mill equipment is plant equipment for pulverizing, drying, classifying, and conveying objects to be pulverized. A crushing unit is composed of rollers and a table, and by pressing against a layered object to be crushed on a rotating table with a driven roller, a compressive force and a shearing force are generated in the object to be crushed. crush things. [0003] As the wear of rollers and table liners progresses, performance declines such as an increase in differential pressure between the inlet and outlet of conveying air due to an increase in electric power and a decrease in crushing capacity, so periodic inspection and repair are required. Become. In Patent Document 1, by modifying the outer peripheral surface of a conical roller having a frustoconical outer peripheral surface into a gently curved surface (tire type), the contact surface pressure of the crushing surface formed by the outer peripheral surface of the roller and the upper surface of the table is reduced. is homogenized, and the wear resistance of the grinding surface can be improved. [0004] Reducing the construction period and cost required for repairing rollers and table surfaces is an important issue because it is related to the operating rate. Rollers can be repaired in a relatively short period of time by replacing the rollers, but repairs on the table side can be done by removing the table liner by means of cutting, fusing, etc., when replacing the table liner provided on the top surface of the table. In the re-mounting work, it is necessary to re-flatten the surface of the table base material on which the table liner is placed so as not to create a gap with the table liner, so the work period is long and the cost is high. Therefore, in Patent Document 2, a proposal is made to reduce the frequency of repair and replacement of the table liner by making the outer peripheral surface of the roller and the table surface a shape that can suppress wear of the table liner from the outer peripheral surface of the roller. is done. prior art documents patent literature [0005] Patent Document 1: Japanese Patent No. 4101709 Patent Document 2: Japanese Patent No. 6469343 SUMMARY OF THE INVENTION Problems to be Solved by the Invention [0006] When replacing a roller with a truncated conical outer peripheral surface with a roller with a gently curved surface, it is thought that the grinding performance will be improved by making the grinding surface of the table a gently curved surface that matches the gently curved surface of the roller. In this case, as described above, replacement of the table liner requires a long construction period and high cost, so it is necessary to secure a construction period that allows simultaneous replacement of the rollers and the table liner. Instead of replacing the table liner, as described in Patent Document 1, it is conceivable to form a gently curved surface by overlay welding over the entire crushed surface. In order to achieve this, there is a problem that a large amount of build-up welding material and a long build-up work are required. [0007] The present disclosure has been made in view of the above-described problems, and aims to provide a roller mill device that can limit the range of forming a curved surface portion on the grinding surface of the table to the minimum necessary range while ensuring the grinding performance. do. Means to solve problems [0008] To achieve the above object, the present disclosure provides a roller mill apparatus comprising a table liner rotatable about a drive axis, and a roller rotatable about a roller axis, pressing against a grinding surface of the table liner. and a roller configured to crush a material to be crushed between the crushing surface and the crushing surface, wherein the outer peripheral surface of the roller is in a state of being pressed toward the crushing surface. is formed in a curved surface shape that is convex toward the crushing surface, and the crushing surface is composed of a flat surface portion formed in a flat shape and the outer peripheral surface of the roller in a state of being pressed toward the crushing surface. and a curved surface portion formed in a concave curved surface shape, wherein the curved surface portion passes through the center position in the width direction of the roller and is perpendicular to the roller axis line and the crushing surface. is formed in a range including at least the first position that is the intersection with In this specification, the term "grinding surface of the table liner" refers to the range of the table surface formed on the top surface of the table liner that faces the outer peripheral surface of the roller pressed toward the table liner. Say "face". [0009] A method for modifying a roller mill apparatus according to the present disclosure also includes a table liner rotatable about a drive axis and a roller rotatable about a roller axis, which is pressed against the grinding surface of the table liner. and a roller configured to grind a material to be ground between the grinding surface, wherein the outer peripheral surface of the roller is pressed toward the grinding surface. The crushing surface is composed of a flat surface portion formed flat and the outer peripheral surface of the roller pressed toward the crushing surface. and a curved surface portion formed in a curved surface shape that is concave toward the roller mill device, and the modification method of the roller mill device includes a center line that passes through the center position in the width direction of the roller and is orthogonal to the roller axis line. and a build-up welding step of forming the curved surface portion by build-up welding in a range including at least a first position that is an intersection point of the pulverized surface. The invention's effect [0010] According to the roller mill device according to the present disclosure, the grinding surface of the table liner includes the flat surface and the curved surface portion, and the curved surface portion is formed in a range including at least the first range on the grinding surface. Therefore, it is possible to limit the range in which the curved surface portion is formed to the minimum necessary range while ensuring the pulverization performance. As a result, the construction period and cost required for forming the curved surface portion can be minimized. Further, according to the modification method of the roller mill device, in addition to the above effects, since the curved surface portion is formed by build-up welding, replacement of the table liner is not required. Therefore, it is possible to shorten the period required for remodeling and reduce the cost. Brief description of the drawing [0011] 1 is a schematic vertical cross-sectional view of a roller mill device according to one embodiment; [Fig. 2] Fig. 2 is a schematic longitudinal sectional view showing a partially enlarged roller mill device according to one embodiment. 3 is a schematic vertical cross-sectional view showing a partially enlarged roller mill device according to one embodiment. [0021]FIG. 4 is a process chart of a method for modifying a roller mill device according to one embodiment; [0022]FIG. 5 is a graph showing the pulverization efficiency of pulverization surfaces according to an embodiment and a comparative example; FIG. MODE FOR CARRYING OUT THE INVENTION [0012] Several embodiments of the present invention will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in these embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. It's nothing more than For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement with a tolerance or an angle or distance to the extent that the same function can be obtained. For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state. For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense, but also include irregularities and chamfers to the extent that the same effect can be obtained. The shape including the part etc. shall also be represented. On the other hand, the expressions "comprising", "comprising", "having", "including", or "having" one component are not exclusive expressions that exclude the existence of other components. [0013] (Overall configuration of roller mill device) FIG. 1 is a schematic longitudinal sectional view showing the overall configuration of the coal pulverizer according to one embodiment in which the roller mill device is applied to the coal pulverizer. The coal pulverizer 10 comprises a housing 12 , a coal feed tube 14 , a table 16 , at least one roller 18 , a primary air feed duct 20 , a rotary classifier 22 and a pulverized coal discharge tube 24 . The coal supply pipe 14 penetrates from above the housing 12 into the inside of the housing 12 and is configured to supply coal as an object to be pulverized to the upper surface of the table 16 . A table 16 is arranged inside the housing 12 . The table 16 is rotatably supported about the driving axis A1 by a rotating shaft 26 arranged in the vertical direction. [0014] In the embodiment shown in FIG. 1, a plurality of rollers 18 are arranged above the table 16 and arranged at regular intervals in the circumferential direction of the table 16 so as to face the table 16 . The roller 18 is configured so as to be able to press the crushing surface formed on the upper surface of the table 16 by its own weight or a pressing device (not shown). The pressing device applies a force with which the roller 18 presses the pulverized surface via the rotating shaft 19 of the roller 18 . The roller 18 follows the crushing surface formed on the upper surface of the table 16 that rotates about the drive axis A 1 and rotates about the roller axis A 2 located at the center of the rotating shaft 19 . Coal supplied from the coal supply pipe 14 is pulverized between the roller 18 and the pulverizing surface to become pulverized coal. [0015] The primary air supply duct 20 supplies primary air from the side surface of the housing 12 under the table 16 and the bottom of the table 16 to the outer peripheral side of the table 16 . An air outlet 28 is provided on the outer peripheral side of the table 16 , and the primary air supplied from the primary air supply duct 20 rises through the air outlet 28 . The pulverized coal produced by the table 16 and the rollers 18 is conveyed by primary air rising from the air outlet 28 . A deflection plate 30 is provided above the air outlet 28 , and the primary air blown out from the air outlet 28 is imparted with swirling force by the deflection plate 30 . The primary air to which the swirling force is imparted by the deflection plate 30 becomes an air current as indicated by the arrow in FIG. Among the pulverized coal mixed with the primary air, those having a large particle size fall due to their own weight without reaching the rotary classifier 22 and are returned to the table 16 again. [0016] The rotary classifier 22 has blades 32 that rotate around the central axis of the housing 12 . The pulverized coal that has reached the rotary classifier 22 together with the primary air has a particle size due to the balance between the centrifugal force applied by the rotating blades 32 and the centripetal force flowing into the rotary classifier 22 from the outer peripheral side of the blades 32. Only small pulverized coal flows inside the blades 32 and exits from the pulverized coal discharge pipe 24 . The pulverized coal discharge pipe 24 communicates with a flow path (not shown) connected to a pulverized coal boiler (not shown). [0017] (Configuration of pulverizing unit including table and rollers) 2 and 3 are partially enlarged vertical cross-sectional views showing an embodiment of a pulverizing unit that includes a table 16 and rollers 18 and pulverizes coal as an object to be pulverized. The table 16 includes a table body 40, a table liner 42, a wedge ring 44 and a dam ring 48, and the like. The table body 40 is rotatably supported by the rotary shaft 26 . The table main body 40 has a circular dish shape, and the upper surface of the table main body 40 constitutes an inclined surface 40a that is inclined so as to become higher toward the outer peripheral side. [0018] The table liner 42 has, for example, an annular shape and is provided on the inclined surface 40 a so as to face the roller 18 . The table body 40 has an annular bank portion 41 that protrudes upward on the inclined surface 40a (on the outer peripheral side of the table liner 42). The outer peripheral edge of the table liner 42 is inserted into and fixed to a recess formed between the table body 40 and the bank 41 . Coal placed on the table liner 42 is ground between the table liner 42 and the rollers 18 . The table liner 42 is used as a replaceable consumable item because it wears due to coal grinding. [0019] The wedge ring 44 has, for example, an annular shape and is positioned inside the table liner 42. More about this source textSource text required for additional translation information Send feedback Side panels History Saved Contribute 5,000 character limit. Use the arrows to translate more.It is provided along the inner peripheral edge of the table liner 42 so as to press the peripheral edge against the table body 40 . The wedge ring 44 is fixed to the rotating shaft 26 with bolts 46 . The dam ring 48 is fixed to the upper surface of the embankment 41 and forms a reservoir space for accumulating pulverized coal pulverized by the roller 18 and the table liner 42 and pushed out onto the table liner 42 on the outer peripheral side of the roller 18 . The pulverized coal stored in the accumulating space is repeatedly pulverized by the rollers 18 to a predetermined particle size. [0020] In this way, the table surface St is formed on the upper surface of the table liner 42, and the coal supplied from the coal supply pipe 14 to the center side region of the table surface St is centrifugally directed toward the outer peripheral side of the table main body 40 by the rotating table main body 40. acts, it gradually moves to the outer peripheral side. Then, it reaches the grinding surface Sg. In this specification, the grinding surface Sg refers to a range of the table surface St that faces the outer peripheral surface of the roller 18 pressed toward the table surface St. The coal reaching the crushing surface Sg is pressed between the roller 18 and the crushing surface Sg and crushed. In FIGS. 2 and 3, m indicates the object to be crushed (coal) deposited on the table surface St in layers. [0021] As shown in FIGS. 2 and 3, the outer peripheral surface 18a of the roller 18 is formed into a curved surface that protrudes toward the grinding surface Sg when the roller 18 is pressed toward the grinding surface Sg. The grinding surface Sg includes flat surface portions 50 (50a, 50b, 50c, 50d) and curved surface portions 52 (52a, 52b). The curved surface portion 52 is formed in a curved surface shape that is concave toward the outer peripheral surface 18a of the roller 18 that is pressed toward the pulverizing surface Sg. In the figure, a line Lc is a center line passing through the center position of the roller 18 in the width direction and orthogonal to the roller axis A2. The curved surface portion 52 is formed in a range including at least the first position P1, which is the intersection of the center line Lc and the grinding surface Sg. As a material for the curved surface portion 52, for example, a wear-resistant material having high strength and toughness is used. [0022] Since the first position P1 is the center position in the width direction of the roller 18 when the roller 18 is pressed toward the crushing surface Sg, a large load is generated between the first position P1 and the curved surface portion 52 to the object to be crushed. It is considered to belong to the range. Therefore, by forming the curved surface portion 52 so as to include at least the first position P1, it is possible to ensure a minimum crushing performance and to limit the formation range of the curved surface portion 52 to the necessary minimum. It is possible to minimize the construction period and cost required for the formation of [0023] In one embodiment, in FIGS. 2 and 3, the outer peripheral surface 18a in contact with the curved surface portion 52 and the surface of the curved surface portion 52 in contact with the outer peripheral surface 18a form curved surfaces having the same radius of curvature. As a result, a uniform load can be applied to the object to be crushed over the entire contact surface between the outer peripheral surface 18a and the curved surface portion 52, so that the crushing performance for the object to be crushed can be improved. [0024] In one embodiment, as shown in FIGS. 2 and 3, when the roller 18 is pressed toward the grinding surface Sg, the outer peripheral surface 18a of the roller 18 is positioned at a first position P1 in the width direction of the roller 18. At a position different from that of the roller axis A2, the tip end 54 is positioned farthest from the roller axis A2. The curved surface portion 52 (52a, 52b) includes at least a first range R1 from the first position P1 to a second position P2 on the grinding surface Sg at a position facing the tip end portion 54. is formed as [0025] The load applied to the object to be crushed by the outer peripheral surface 18a of the roller 18 and the crushing surface Sg is considered to be the largest at the second position P2. Therefore, it is considered that the load applied to the object to be crushed is greatest in the first range R1 including the first position P1 and the second position P2. According to this embodiment, since the curved surface portion 52 is formed so as to include at least the first range R1, it is possible to enhance the crushing performance for the object to be crushed. On the other hand, since the formation of the curved surface portion 52 is limited to the first range R1, the construction period and cost required for forming the curved surface portion 52 can be suppressed. [0026] In one embodiment, as shown in FIGS. 2 and 3, the second position P2 on the crushing surface Sg facing the most protruding end 54 of the roller outer peripheral surface 18a is located on the outer peripheral side of the first position P1. do. Therefore, the load applied to the object to be crushed between the roller outer peripheral surface 18a and the crushing surface Sg increases outside the first position P1 in the radial direction of the table 16 . Therefore, when the object m to be crushed is supplied to the center side of the table 16 and travels toward the peripheral side of the table 16 through the crushing surface Sg, the object m to be crushed is placed on the outer peripheral side of the traveling direction of the object m to be crushed from the first position P1. can be increased, the object to be crushed m is crushed step by step from coarse particles to fine particles. Therefore, it can be pulverized to a predetermined particle size with high precision. [0027] In one embodiment, as shown in FIGS. 2 and 3, a region of the outer peripheral surface 18a of the roller 18 that is radially outward of the table 16 from the first position P1 is the first position outside the center line Lc. 1 Curvature center C It is formed by an arc centered on 1. The most protruding end 54 is formed at a second position P2 where a straight line L1 passing through the first center of curvature C1 and parallel to the center line Lc intersects the grinding surface Sg. Further, the outer peripheral surface 18a radially inward of the table 16 from the first position P1 is formed in an arc centered on the second center of curvature C2 on the center line Lc. The radius of curvature r2 of the arc around the second center of curvature C2 is greater than the radius of curvature r1 of the arc around the first center of curvature C1. [0028] According to this embodiment, the load generated on the grinding surface Sg can form a load distribution that gradually increases from the inner side to the outer side of the table 16 in the radial direction. As a result, the object to be pulverized is pulverized so that the particle size gradually decreases from the inside to the outside of the pulverizing surface Sg, so that it can be pulverized to a predetermined particle size with high accuracy. Further, since r1