A coal mill grinding coupling device and its usage method

Abstract

The present invention discloses a grinding mill grinding coupling device and a using method thereof, belonging to the technical field of grinding mills and located inside the grinding mill housing. The grinding mill grinding coupling device includes: a grinding table, the grinding table having a lining plate and a tray. Along the extending direction of the lining plate, the upper surface of the lining plate successively has: a first plane, a contact surface, and a second plane. The first plane is farther from the grinding mill housing than the second plane, and the contact surface is the grinding area of the grinding mill; a moving ring, which is an airfoil wind ring. The airfoil wind ring has an inner wind ring and an outer wind ring. The inner wind ring is installed on the tray, and the outer wind ring is sleeved on the circumferential outer side of the inner wind ring, and a cavity that first contracts and then expands in the upward direction is formed between the outer wind ring and the inner wind ring, and blades are arranged in the cavity. The profile lines of the lining plate and the grinding rollers are increased, the output value of the grinding area is improved, the boiler load of the power plant is increased, the flow channel is optimized to stabilize the central flow field of the grinding mill, it is more suitable for the increase of the output of the grinding mill, and the pressure difference of the grinding mill is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mills, and particularly relates to a grinding coupling device for a coal mill and a usage method thereof. Background Art

[0002] At present, more than 90% of coal-fired power plants in China use pulverized coal combustion for power generation. Among them, ZGM type coal mills account for a relatively large proportion in the auxiliary equipment of power plants. With the continuous increase in the price of coal quality, the coal quality used in thermal power plants varies, seriously deviating from the original designed coal type. The raw coal has a large moisture content and a low Hardgrove grindability index, which is common. Due to the change in coal quality, the actual output of the coal mill cannot meet the combustion demand of the boiler, severely restricting the output level of the coal mill.

[0003] At present, the structural design concept of the grinding device in the existing ZGM type coal mills is fixed, and the grinding area is limited. The ZGM(G) type belongs to a relatively large model among coal mills. To improve the output of the coal mill, it is mainly achieved by increasing the speed of the reducer. It will become more difficult to further increase the output of the coal mill after increasing the speed. In order to increase the output, the coal mill needs to run continuously at full load, and there is no standby coal mill, which poses a safety hazard to production.

[0004] In view of the above problems, there is an urgent need to develop a grinding coupling device that is suitable for a relatively large model of coal mill and uses a special grinding profile to improve the output value of the coal mill. Summary of the Invention

[0005] In order to at least solve the problem of low output value of the coal mill in the prior art, the present invention provides the following technical solution: A grinding coupling device for a coal mill, located inside the coal mill housing. The grinding coupling device for the coal mill includes:

[0006] A grinding table, the grinding table having a lining plate and a tray. Along the extension direction of the lining plate, the upper surface of the lining plate sequentially has: a first plane, a contact surface, and a second plane. The first plane is farther from the coal mill housing than the second plane, and the height of the first plane is lower than the height of the second plane. The contact surface is the grinding area of the coal mill;

[0007] A moving ring, which is an airfoil wind ring. The airfoil wind ring has an inner wind ring and an outer wind ring. The inner wind ring is installed on the tray, and the outer wind ring is sleeved on the circumferential outer side of the inner wind ring, and a cavity that first contracts and then expands in the upward direction is formed between the outer wind ring and the inner wind ring. Blades are arranged in the cavity.

[0008] Preferably, the width of the first plane is less than or equal to the width of the second plane.

[0009] Preferably, the grinding coupling device for the coal mill further includes: a grinding roller, the grinding roller being located above the lining plate and the bottom thereof being in contact with the contact surface;

[0010] The maximum outer diameter Dg of the grinding roller is (4 / 5)×D0, where D0 is the diameter of the grinding disc, in mm;

[0011] The width Bg of the grinding roller is 1 / 3Dg + 20, in mm;

[0012] Half of the central angle θg of the outer arc of the grinding roller is 40 - 43°;

[0013] The outer arc radius Rg of the grinding roller is (Bg / 2) / Sinθg, in mm;

[0014] The thickness dg of the outer arc wall of the grinding roller is 4 / 25Dg, in mm;

[0015] The arc radius Rc of the lining plate is 9 / 8Rg ± 10, in mm;

[0016] The central thickness δc of the lining plate is 0.05D0, in mm;

[0017] The wrap angle α of the lining plate is between 30 - 40°.

[0018] Preferably, the inner side walls of the upper part and the middle part of the outer air ring are both straight, and the inner side wall of the lower part is an arc-shaped line that bends from the inside to the outside;

[0019] The outer side wall of the upper part of the inner air ring is an arc-shaped line that bends from the outside to the inside, the outer side wall of the middle part is straight, and the outer side wall of the lower part is an arc-shaped line that bends from the inside to the outside.

[0020] Preferably, the length of the inner side wall of the upper part of the outer air ring is greater than the length of the inner side wall of the middle part of the outer air ring.

[0021] Preferably, the inner side walls of the upper part and the middle part of the outer air ring are both vertical straight lines, and the inner diameters of the inner side walls of the upper part and the middle part of the outer air ring are equal;

[0022] The outer side wall of the middle part of the inner air ring is a vertical straight line;

[0023] The middle part of the inner air ring is arranged opposite to the middle part of the outer air ring.

[0024] Preferably, the inner side wall of the outer air ring and the outer side wall of the inner air ring are both smooth surfaces;

[0025] The flow direction of the primary air flowing through the cavity is in the vertical direction.

[0026] Preferably, a wind shield ring is installed at the top of the outer air ring, and the top of the outer air ring is higher than the top of the inner air ring.

[0027] Preferably, the milling coupling device of the coal mill further comprises: a stationary ring connected to the housing of the coal mill;

[0028] The stationary ring is an air-powder diversion ring, located above the outer air ring to form a horizontal gap between the air-powder diversion ring and the outer air ring. The inner side wall of the upper part of the air-powder diversion ring is inclined towards the axis of the air-powder diversion ring, and the inner side wall of the lower part of the air-powder diversion ring is inclined away from the axis of the air-powder diversion ring.

[0029] The present invention also provides a method for using the milling coupling device of the coal mill. The milling coupling device of the coal mill is the above-mentioned milling coupling device of the coal mill. The method for using includes:

[0030] Adding raw coal into the coal mill so that it falls onto the lining plate in the milling coupling device;

[0031] Driving the tray to rotate by external force, and the tray drives the upper lining plate and the outer moving ring to rotate to perform centrifugal motion;

[0032] The raw coal moves to the milling area of the coal mill by the centrifugal force of the lining plate and is milled into pulverized coal;

[0033] While milling, guiding the primary air into the cavity of the moving ring. Then, the primary air uniformly enters the periphery of the lining plate after passing through the blades between the inner air ring and the outer air ring, dries the air-powder mixture that is tangentially thrown out from the lining plate after milling. The air-powder mixture spirally rises in the housing of the coal mill to form a rotating air-powder flow. The rotating air-powder flow reaches the upper flow field of the coal mill for separation. Then, the separated coarse powder is diverted and returned to the lining plate for re-milling, and the qualified fine powder is carried out of the coal mill by the primary air.

[0034] The beneficial effects brought by the technical solution provided by the embodiment of the present invention are:

[0035] The lining plate and the grinding roller are modified to increase the profile line, both of which are the largest profile line sizes of the same model, so that the area of the milling area is maximized. The milling output value of the coal mill is increased within the same time, the pulverized coal output is increased. The lining plate and the grinding roller cooperate with each other to fully crush the raw coal by rolling, achieve the target output value in a shorter time, shorten the operation time of the coal mill, increase the boiler load of the power plant, and meet the daily production needs;

[0036] The profile line designs of the inner air ring and the outer air ring in the moving ring both borrow from the airfoil model, and the overall is similar to the upper and lower surfaces of the wing. When the primary air passes through multiple primary air inlet passages between the inner air ring and the outer air ring, the speed at the outer side wall of the upper part of the inner air ring is higher than the speed at the inner side wall of the upper part of the outer air ring, forming a low pressure at the outer side wall of the upper part of the inner air ring, and also generating a certain pressure difference, which promotes the primary air to flow towards the middle, thereby reducing the inert area in the middle flow field and being more adaptable to the increase of the output of the coal mill;

[0037] On the upper and lower parts of the inner side wall of the air-powder diversion ring, two inclined walls in different directions are provided to guide the primary air to the middle of the coal mill for diversion, reduce the erosion of the primary air on the inner side wall of the air-powder diversion ring, increase the stability of the middle flow field, and reduce the wear of the primary air on the casing of the coal mill. Description of the Drawings

[0038] Figure 1 It is a schematic structural diagram of a grinding coupling device for a coal mill provided by an embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram for comparing the before and after optimization of the profile lines of the grinding roller and the liner in a grinding coupling device for a coal mill provided by an embodiment of the present invention;

[0040] Figure 3 It is a schematic structural diagram of an airfoil wind ring in a grinding coupling device for a coal mill provided by an embodiment of the present invention;

[0041] Figure 4 It is a schematic structural diagram of a blade in a grinding coupling device for a coal mill provided by an embodiment of the present invention;

[0042] In the figure: 1, air-powder diversion ring; 2, transition flange; 3, support; 4, outer wind ring; 401, upper part of the outer wind ring; 402, middle part of the outer wind ring; 403, lower part of the outer wind ring; 5, connecting bolt; 6, tray; 7, liner; 8, grinding roller; 9, pressing bolt; 10, coal mill casing; 11, driving disc; 12, inner wind ring; 1201, upper part of the inner wind ring; 1202, middle part of the inner wind ring; 1203, lower part of the inner wind ring; 13, first plane; 14, contact surface; 15, second plane; 16, wind shield ring. Detailed Embodiment

[0043] To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0044] In the description of the present invention, the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. The terms "connected", "connected to", and "provided with" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can be a wired electrical connection, a radio connection, or a wireless communication signal connection. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0045] Please refer to Figures 1-4 , the present invention provides a grinding mill grinding coupling device located inside the grinding mill housing 10, including: a grinding table and a moving ring.

[0046] The grinding table has a lining plate 7 and a tray 6. The number of the lining plates 7 is multiple, and the multiple lining plates 7 enclose a ring. The lining plate 7 has an upper surface. For example, Figure 1 the left surface of the lining plate 7 in the figure, along the extension direction of the lining plate 7, that is, from the inner end to the outer end of the lining plate 7, the upper surface of the lining plate 7 successively has: a first plane 13, a contact surface 14, and a second plane 15. The second plane 15 is closer to the grinding mill housing 10 than the first plane 13, and the height of the second plane 12 is higher than the height of the first plane 13. The contact surface 14 is the grinding area of the grinding mill, which is an arc surface. The raw coal enters the contact surface 14 to prepare for the grinding process. Further, the width L1 of the first plane 13 is less than or equal to the width L2 of the second plane 15. In this way, it is beneficial for the raw coal to accumulate better at the first plane 13 of the lining plate 7. By ensuring a certain amount of raw coal can be stored at the first plane 13 of the lining plate 7, it can better guide the raw coal to the rolling center under the action of centrifugal force and promote the grinding of the raw coal.

[0047] The lining plate 7 is fixed on the tray 6 by vertically arranged compression bolts 9. The lining plate 7 can be pressed tightly on the tray 6 through the compression bolts 9, and at the same time, it plays a fastening role.

[0048] The moving ring is an airfoil air ring, which has an inner air ring 12 and an outer air ring 4. The inner air ring 12 is installed on the tray 6 through the connecting bolts 5. The bottom of the tray 6 is connected to the driving disc 11. The tray 6 can rotate driven by the driving disc 11, and at the same time drive the inner air ring 12 to rotate. The outer air ring 4 is sleeved on the circumferential outer side of the inner air ring 12, and a cavity that first contracts and then expands in the direction from bottom to top is formed between the outer air ring 4 and the inner air ring 12. The cavity wall is composed of the outer side wall of the inner air ring 12 and the inner side wall of the outer air ring 4. The blades are arranged in the cavity, and they can be connected between the inner air ring 12 and the outer air ring 4. In this way, the outer air ring 4 is sleeved on the circumferential outer side of the inner air ring 12 through the blades. A number of blades are evenly and obliquely distributed between the inner air ring 12 and the outer air ring 4 along the circumferential direction of the inner air ring 12 or the outer air ring 4. For example, the blades form an angle of 40° with the horizontal plane. The blades evenly divide the cavity into multiple primary air inlet passages. The lower part of the primary air inlet passage has a primary air inlet, and the upper part has a primary air outlet. When the inner air ring 12 rotates, it also drives the outer air ring 4 to rotate through the blades to form primary air. The primary air forms a flow from bottom to top in the primary air inlet passage from the primary air inlet to the primary air outlet.

[0049] In the radial direction, the top of the inner air ring 12 is opposite to the top of the lining plate 7, and the two are on the same horizontal plane. The lining plate 7 will not block the primary air coming out of the primary air outlet, which is beneficial to the flow of the primary air to the middle flow field of the coal mill.

[0050] The grinding roller 8 is inclinedly installed in the coal mill. For example, the included angle with the vertical direction is 15°.

[0051] In order to improve the grinding efficiency and increase the output value of the coal mill, the profile lines of the grinding roller 8 and the lining plate 7 are optimized to maximize the area of the grinding area. The specific profile line parameters are as follows:

[0052] The maximum outer diameter Dg of the grinding roller 8 = (4 / 5)×D0, where D0 is the diameter of the grinding disc, in mm;

[0053] The width Bg of the grinding roller 8 = 1 / 3Dg + 20, in mm;

[0054] Half of the central angle of the outer arc of the grinding roller 8, θg = 40 - 43°;

[0055] The outer arc radius Rg of the grinding roller 8 = (Bg / 2) / Sinθg, in mm;

[0056] The thickness dg of the outer arc wall of the grinding roller 8 = 4 / 25Dg, in mm;

[0057] The arc radius Rc of the lining plate 7 = 9 / 8Rg ± 10, in mm;

[0058] The central thickness δc of the lining plate 7 = 0.05D0, in mm;

[0059] The wrap angle α of the liner 7 is between 30° and 40°.

[0060] Among them, the relevant positions of Dg, D0, Bg, θg, Rg, dg, Rc, δc, and the wrap angle α of the liner 7 are as Figure 2 shown. Compared with the prior art, the grinding profiles of the grinding rolls 8 and the liners 7 of the same model are both larger than before. Specifically, the outer arc radius of the grinding rolls 8 and the liners 7 is increased; the width of the grinding rolls 8 is increased; the wrap angle design of the liners 7 is smaller and is selected between 30° and 40°. Thereby, the grinding rolls 8 can make the best use of the grinding space within the allowable grinding range; the profile matching between the grinding rolls 8 and the liners 7 is smoother; the projected area of the grinding rolls 8 in the grinding area is increased, thereby increasing the effective grinding efficiency of the grinding rolls 8 and the liners 7. At the same time, the first plane 13 is designed from an original arc to a horizontal straight line, which is conducive to the diversion of raw coal, so as to better grind the raw coal.

[0061] The grinding roll 8 includes a roll core and a roll sleeve, and the roll sleeve is sleeved on the outside of the roll core. When the drive disk 11 drives the tray 6 to rotate, and then drives the liner 7 to rotate, the grinding roll 8 slides on the upper surface of the liner 7, and a frictional force that hinders their relative movement is generated on the contact surface between the two. The grinding roll 8 rotates circumferentially through the frictional force. The grinding roll 8 rotates in contact with the upper surface of the liner 7, and the contact area between the two constitutes the grinding area. The raw coal is located on the liner 7, and the grinding roll 8 directly contacts the raw coal. The relative movement between the grinding roll 8 and the liner 7 squeezes and crushes the raw coal into pulverized coal.

[0062] The contact surface 14 is an arc-shaped curved surface. Due to the optimization of the liner 7, the profile is increased, so that the surface area of the contact surface 14 is increased. In order to match the contact surface 14, the grinding roll 8 is also optimized and the profile is increased.

[0063] The number of grinding rolls 8 is three and they are evenly distributed in the grinding area.

[0064] A tubular protrusion is provided at the center of the tray 6, and the tubular protrusion of the tray 6 is installed inside the through hole of the liner 7.

[0065] The top of the drive disk 11 is inserted inside the tubular protrusion, and a top plate is provided above the drive disk 11. The top plate is fixedly connected to the top of the tubular protrusion, and the top plate can prevent pulverized coal from entering the inside of the drive disk 11.

[0066] In order to press the liner 7 tightly on the tray and play a fastening role at the same time, the liner 7 is fixed on the tray 6 through a vertically arranged pressing bolt 9. The pressing bolt 9 is located between the tubular protrusion and the first plane 13 and the top is in the shape of an inverted frustum.

[0067] To facilitate the flow of the primary air, the inner sidewalls of the upper part 401 and the middle part 402 of the outer air ring are both straight, and the inner sidewall of the lower part 403 is an arc-shaped curve that bends from the inside to the outside; the outer sidewall of the upper part 1201 of the inner air ring is an arc-shaped curve that bends from the outside to the inside, the outer sidewall of the middle part 1202 is straight, and the outer sidewall of the lower part 1203 is an arc-shaped curve that bends from the inside to the outside. Further, the length of the inner sidewall of the upper part 401 of the outer air ring is greater than the length of the inner sidewall of the middle part 402 of the outer air ring.

[0068] The design principle of the moving ring is described below: The region enclosed by the inner sidewall of the middle part 402 of the outer air ring, the outer sidewall of the middle part 1202 of the inner air ring, the inner sidewall of the lower part 403 of the outer air ring, and the outer sidewall of the lower part 1203 of the inner air ring forms a Venturi effect model. According to the Venturi effect and Bernoulli's equation, C = P+(1 / 2)*ρv^2+ρgh, it can be known that when a certain fluid passes through the contraction section, the flow velocity increases. When the flow velocity increases, its pressure decreases, forming a low pressure, thus generating an adsorption effect, which can better promote the fluid to pass through. At the same time, the region enclosed by the inner sidewall of the upper part 401 of the outer air ring, the inner sidewall of the middle part 402 of the outer air ring, the outer sidewall of the middle part 1202 of the inner air ring, the outer sidewall of the upper part 1201 of the inner air ring, and the outer sidewall of the lower part 1203 of the inner air ring makes use of the airfoil model. The whole is similar to the upper and lower surfaces of an airplane wing, that is, the outer sidewall of the inner air ring 12 is similar to the upper surface of the airfoil, and the inner sidewall of the outer air ring 4 is similar to the lower surface of the airfoil. When the fluid passes through, the velocity at the outer sidewall of the upper part 1201 of the inner air ring is higher than the velocity at the inner sidewall of the upper part 401 of the outer air ring. A low pressure is formed at the outer sidewall of the upper part 1201 of the inner air ring, and a certain pressure difference is also generated, which promotes the primary air to flow towards the middle, thereby reducing the inert zone in the middle flow field and reducing the wear of the mill housing 10. At the same time, it can improve the pressure difference of the mill to a certain extent and avoid the reduction of output caused by a large pressure difference of the mill.

[0069] The inner sidewall of the outer air ring 4 and the outer sidewall of the inner air ring 12 are both smooth surfaces; the inner sidewalls of the upper part 401 and the middle part 402 of the outer air ring are both vertical straight lines, and the inner diameters of the inner sidewalls of the upper part 401 and the middle part 402 of the outer air ring are equal; the outer sidewall of the middle part 1202 of the inner air ring is a vertical straight line, which further facilitates the flow of the primary air. The middle part 1202 of the inner air ring is arranged opposite to the middle part 402 of the outer air ring. It should be noted that the opposite arrangement can be directly opposite, that is, in Figure 1In [description], the projection of the middle part 1202 of the inner air ring on the outer air ring 4 is completely located in the middle part 402 of the outer air ring; or they can be staggered relative to each other, that is, part of the projection of the middle part 1202 of the inner air ring on the outer air ring 4 is located in the middle part 402 of the outer air ring, and part is located outside the middle part 402 of the outer air ring. Through the design of the airfoil air ring, when the flow direction of the primary air in the cavity is vertical, the stability of the middle flow field can be improved, and at the same time, it is also beneficial to the installation of the air ring.

[0070] A wind shield ring 16 is installed at the top of the outer air ring 4, which is convenient for replacing the wind shield ring 16. The wind shield ring 16 can control the fluid flow rate or flow direction through the blades, and at the same time can radially block a certain range of primary air. The top of the outer air ring 4 is higher than the top of the inner air ring 12, which is beneficial to the flow of the primary air in the direction of the lining plate 7, so that the primary air can carry out the pulverized coal fully crushed in the grinding area out of the coal mill.

[0071] The stationary ring is connected to the coal mill housing 10 and is the air and powder diversion ring 1. Its bottom end is connected with a transition flange 2 located above the support 3, and the transition flange 2 is connected to the coal mill housing 10. The air and powder diversion ring 1 is located above the outer air ring 4 to form a horizontal gap between the air and powder diversion ring 1 and the outer air ring 4. The inner side wall of the upper part of the air and powder diversion ring 1 is inclined towards the direction close to the axis line of the air and powder diversion ring 1, and the inner side wall of the lower part of the air and powder diversion ring 1 is inclined towards the direction away from the axis line of the air and powder diversion ring 1. This is convenient for guiding the primary air to flow towards the middle of the coal mill, increasing the stability of the middle flow field, and reducing the wear of the hot air after passing through the moving ring on the coal mill housing 10.

[0072] The present invention also provides a use method of a grinding and milling coupling device for a coal mill. It should be noted that the above-mentioned grinding and milling coupling device is used in this method, and the use method includes:

[0073] Add the raw coal into the coal mill through the central coal dropping pipe of the coal mill, and the raw coal just falls onto the lining plate 7 in the grinding and milling coupling device.

[0074] With the help of the main motor and the reducer of the power supply device, drive the driving disk 11 to rotate. The driving disk 11 drives the fixedly connected tray 6 to rotate, and the tray 6 drives the upper lining plate 7 and the outer moving ring to rotate and do centrifugal motion.

[0075] The raw coal relies on the centrifugal force of the lining plate 7. The centrifugal force makes the raw coal on the lining plate 7 move away from the rotation center of the lining plate 7, and the raw coal moves to the grinding area of the coal mill (that is, the contact surface 14 of the lining plate 7) and is ground into pulverized coal by the grinding roller 8.

[0076] The grinding and drying are carried out simultaneously. The primary air is guided into the cavity formed between the outer air ring 4 and the inner air ring 12 of the moving ring, which first contracts and then expands in the upward direction. After that, the primary air uniformly enters the periphery of the lining plate 7 after passing through the blades between the inner air ring 12 and the outer air ring 4. The primary air dries the air-powder mixture that is tangentially thrown out from the lining plate 7 after grinding. The air-powder mixture spirally ascends in the mill casing 10 to form a rotating air-powder flow. The rotating air-powder flow reaches the flow field at the upper part of the mill and is separated by a separator. Then, the coarse powder separated is guided back to the lining plate 7 by the stationary ring for re-grinding, and the qualified fine powder is carried out of the mill by the primary air.

[0077] As is known by common technical knowledge, the present invention can be implemented by other embodiments that do not depart from its spiritual essence or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A grinding coupling device for a coal mill, which is located inside the housing of the coal mill, is characterized in that, The grinding mill grinding coupling device includes: A grinding table, the grinding table having a lining plate and a tray. Along the extending direction of the lining plate, the upper surface of the lining plate sequentially has: a first plane, a contact surface, and a second plane. The first plane is farther from the grinding mill housing than the second plane, and the height of the first plane is lower than the height of the second plane. The contact surface is the grinding area of the grinding mill. A moving ring, which is an airfoil air ring. The airfoil air ring has an inner air ring and an outer air ring. The inner air ring is installed on the tray. The outer air ring is sleeved on the circumferential outer side of the inner air ring, and a cavity that first contracts and then expands in the upward direction is formed between the outer air ring and the inner air ring. Blades are arranged in the cavity. The flow direction of the primary air flowing through the cavity is in the vertical direction. The top end of the outer air ring is higher than the top end of the inner air ring. A grinding roller, the grinding roller being located above the lining plate and the bottom thereof abutting against the contact surface. The maximum outer diameter Dg of the grinding roller = (4 / 5)×D0, where D0 is the diameter of the grinding table, in mm. The width Bg of the grinding roller = 1 / 3Dg + 20, in mm. Half of the central angle of the outer arc of the grinding roller θg = 40 - 43°. The outer arc radius Rg of the grinding roller = (Bg / 2) / Sinθg, in mm. The thickness dg of the outer arc wall of the grinding roller = 4 / 25Dg, in mm. The arc radius Rc of the lining plate = 9 / 8Rg ± 10, in mm. The central thickness δc of the lining plate = 0.05D0, in mm. The wrap angle α of the lining plate is between 30 - 40°.

2. The grinding coupling device of a coal mill according to claim 1, wherein, The width of the first plane is less than or equal to the width of the second plane.

3. The grinding mill grinding coupling device according to claim 1, characterized in that, The inner side wall of the upper part and the inner side wall of the middle part of the outer air ring are both straight lines, and the inner side wall of the lower part is an arc-shaped line that bends from the inside to the outside. The outer side wall of the upper part of the inner air ring is an arc-shaped line that bends from the outside to the inside, the outer side wall of the middle part is a straight line, and the outer side wall of the lower part is an arc-shaped line that bends from the inside to the outside.

4. The grinding mill grinding coupling device according to claim 3, wherein The length of the inner side wall of the upper part of the outer air ring is greater than the length of the inner side wall of the middle part of the outer air ring.

5. The grinding mill grinding coupling device according to claim 3, characterized in that, The inner side wall of the upper part and the inner side wall of the middle part of the outer air ring are both vertical straight lines, and the inner diameters of the inner side wall of the upper part and the inner side wall of the middle part of the outer air ring are equal. The outer side wall of the middle part of the inner air ring is a vertical straight line. The middle part of the inner air ring is arranged opposite to the middle part of the outer air ring.

6. The grinding coupling device of a coal mill according to claim 3, characterized in that, The inner side wall of the outer air ring and the outer side wall of the inner air ring are both smooth surfaces.

7. The grinding coupling device of a coal mill according to claim 3, characterized in that A wind shield ring is installed at the top end of the outer air ring.

8. A coal mill grinding coupling device according to claim 1, characterized in that, The grinding mill grinding coupling device further includes: a stationary ring connected to the grinding mill housing. The stationary ring is an air and powder diversion ring, located above the outer air ring to form a horizontal gap between the air and powder diversion ring and the outer air ring. The inner side wall of the upper part of the air and powder diversion ring is inclined towards the axis line of the air and powder diversion ring, and the inner side wall of the lower part of the air and powder diversion ring is inclined away from the axis line of the air and powder diversion ring.

9. A method for using a grinding and milling coupling device of a coal mill, wherein the grinding and milling coupling device of the coal mill is the grinding and milling coupling device according to any one of claims 1-8, characterized in that, The usage method includes: Add raw coal into the coal mill so that it falls onto the lining plate in the grinding coupling device; Drive the tray to rotate with the help of external force. The tray drives the upper lining plate and the moving ring on the outside to rotate and make a centrifugal motion; The raw coal moves to the grinding area of the coal mill by means of the centrifugal force of the lining plate and is ground into pulverized coal; While grinding, guide the primary air into the cavity of the moving ring. After that, the primary air uniformly enters the periphery of the lining plate after passing through the blades between the inner air ring and the outer air ring, drying the air-powder mixture that is tangentially thrown out from the lining plate after grinding. The air-powder mixture spirally rises in the coal mill casing to form a rotating air-powder flow. The rotating air-powder flow reaches the upper flow field of the coal mill for separation. After that, the separated coarse powder is diverted and returned to the lining plate for re-grinding, and the qualified fine powder is carried out of the coal mill by the primary air.

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