Movable ring and nozzle device with same

Abstract

The utility model discloses a moving ring and a nozzle device with the same, and belongs to the technical field of coal mills, the moving ring is provided with an inner air ring and an outer air ring, the inner air ring is used for being installed on a millstone tray, the outer air ring is sleeved on the circumferential outer side of the inner air ring, a flow channel which is not changed after gradually shrinking in the direction from bottom to top is formed between the outer air ring and the inner air ring, and the flow channel is communicated with the inner air ring. The flow channel deflects towards the direction of the axis of the inner air ring relative to the vertical direction, and flow guide blades are distributed in the flow channel. A nozzle device is located in a coal mill shell and comprises a movable ring, a movable ring, a rotary shaft, a rotary shaft and a rotary shaft, the static ring is located above the movable ring, and the static ring is connected with the machine shell through a supporting ring; the line type of the inner side wall of the static ring is matched with the line type of the inner side wall of the outer air ring. According to the runner of the moving ring, the average flow area of a nozzle basin can be increased, the local primary air resistance of the nozzle is effectively reduced, the local resistance of the whole moving ring is reduced, the primary air diffusion area of an outlet is increased, and machine shell abrasion is effectively reduced.

Description

Technical Field

[0001] This utility model belongs to the field of coal mill technology and relates to a moving ring and a nozzle device having the moving ring. Background Technology

[0002] Thermal power generation is the main source of electricity in my country. Coal mills, as the main equipment in the pulverizing system, are characterized by their compact structure, low noise, and low power consumption, and are widely used in thermal power plants.

[0003] The main working principle of a coal mill is that raw coal is ground into fine powder on the grinding disc, and then carried by the high-speed airflow ejected from the rotating nozzle ring to the separator for separation, ultimately yielding qualified coal powder. The function of the rotating and stationary rings is to convert low-speed airflow into high-speed airflow, improving the powder-carrying capacity of the airflow. This results in a higher flow velocity near the nozzle ring, causing the rotating and stationary rings to wear faster under the action of the air-powder flow, especially the upper part of the nozzle ring, which is the main wear location during operation. In addition, the airflow velocity in the radial direction of a conventional nozzle ring is zero (pointing towards the center of the grinding disc), and the blades of the nozzle ring have a "straight section plus comma" structure. This blade structure has long suffered from problems such as difficult maintenance, high resistance, and severe wear of the casing.

[0004] Therefore, it is necessary to provide a rotating ring that reduces wear of the rotating and stationary rings by the air-powder flow, and a nozzle device having the rotating ring. Utility Model Content

[0005] To at least address the problem of rapid wear of the nozzle moving ring under the action of air and powder flow in the prior art, this utility model provides the following technical solution: a moving ring for a nozzle device.

[0006] The moving ring has an inner air ring and an outer air ring. The inner air ring is used to install on the grinding disc tray. The outer air ring is sleeved on the circumferential outer side of the inner air ring and forms a flow channel between the outer and inner air rings that gradually narrows from bottom to top and remains unchanged. The flow channel is deflected relative to the vertical direction toward the axis of the inner air ring, and guide vanes are arranged in the flow channel.

[0007] Optionally, in the aforementioned moving ring for the nozzle device, the height of the top of the outer air ring is higher than the height of the top of the inner air ring, and the height of the bottom of the outer air ring is higher than the height of the bottom of the inner air ring.

[0008] Optionally, in the aforementioned nozzle device moving ring, multiple layers of the guide vanes are spaced apart in the flow channel from bottom to top to reduce the characteristic length of the flow channel.

[0009] Optionally, in the above-mentioned moving ring for the nozzle device, in the direction from top to bottom, the top to 1 / 5 to 1 / 3 of the inner wall of the outer air ring is a straight line with an angle of 10° to 20° to the vertical direction, and the 1 / 5 to 1 / 3 of the inner wall of the outer air ring to the bottom is a spline curve that curves from the inside to the outside.

[0010] In the direction from top to bottom, the top to 1 / 5 to 1 / 3 of the outer wall of the inner wind ring is a straight line with an angle of 10° to 20° to the vertical direction, and the bottom of the 1 / 5 to 1 / 3 of the outer wall of the inner wind ring is a spline curve that curves from the inside to the outside.

[0011] A primary airflow moves from bottom to top along the channel.

[0012] Optionally, in the moving ring of the above-mentioned nozzle device, in the direction from top to bottom, the top to 1 / 4 to 1 / 3 of the guide vane is a straight line with an angle of 40° to 50° with the horizontal plane, and the 1 / 4 to 1 / 3 of the guide vane to the bottom 3 / 4 is a spline curve, and the angle between the bottom tangent direction of the spline curve and the vertical direction is 0° to 15°.

[0013] Optionally, in the above-mentioned nozzle device moving ring, the moving ring is composed of an upper double ring body and a lower double ring body;

[0014] The upper end of the lower double ring body is provided with an annular groove that spans both sides of the flow channel, for supporting the upper double ring body;

[0015] The upper double ring and the lower double ring are detachably connected; and

[0016] The upper double ring is made of wear-resistant material.

[0017] Optionally, in the moving ring of the nozzle device described above, a first guide vane is arranged in the flow channel located in the upper double ring body, and the angle between the first guide vane and the horizontal plane is 10 to 15°.

[0018] A second guide vane is arranged in the flow channel located in the lower double ring body, and the angle between the second guide vane and the horizontal plane is 15-25°.

[0019] Optionally, in the aforementioned nozzle device moving ring, the outer side wall of the upper end of the outer air ring extends radially outward to form an annular boss.

[0020] This utility model also provides the following technical solution: a nozzle device located inside the casing of a coal mill, the nozzle device comprising:

[0021] The rotating ring is a rotating ring for a nozzle device as described above;

[0022] A stationary ring, located above the rotating ring, is connected to the housing via a support ring;

[0023] The profile of the inner wall of the static ring matches the profile of the inner wall of the outer air ring.

[0024] Optionally, in the above-described nozzle device, the outer side wall of the upper end of the outer air ring extends radially outward to form an annular boss;

[0025] A horizontal gap of 5 to 10 mm is formed between the top of the annular boss and the stationary ring;

[0026] A vertical gap of 8 to 20 mm is formed between the outer wall of the annular boss and the support ring.

[0027] The beneficial effects of the technical solution provided by this utility model embodiment are:

[0028] In this application, the moving ring has a flow channel composed of an inner air ring and an outer air ring that is reduced in the direction from bottom to top but remains unchanged. This streamlined opening (inlet) method can increase the average flow area of ​​the nozzle flow domain. The local resistance is proportional to the characteristic length of the nozzle, effectively reducing the local primary air resistance of the nozzle. The upper part of the flow channel adopts a reduced flow channel design with an inward angle, which can ensure that the local resistance of the entire moving ring is reduced without reducing the performance of the flow channel. This solves the problem of the moving ring wearing out quickly under the action of air and powder flow, while increasing the primary air diffusion area at the outlet and effectively reducing the wear of the casing.

[0029] In this application, the flow channel in the dynamic ring is deflected relative to the vertical direction toward the axis of the inner air ring, that is, deflected toward the direction closer to the grinding disc, which can increase the dust-carrying capacity of the primary air. Attached Figure Description

[0030] Figure 1 A longitudinal cross-sectional view of a moving ring for a nozzle device provided in an embodiment of this utility model;

[0031] Figure 2 A top view of the guide vanes arranged in the flow channel of the moving ring of a nozzle device provided in an embodiment of this utility model.

[0032] Figure 3 This is a longitudinal cross-sectional structural diagram of a nozzle device provided in an embodiment of the present utility model;

[0033] Figure 4 This is a schematic diagram of a conventional nozzle ring.

[0034] In the diagram: 1. Moving ring; 11. Inner air ring; 12. Outer air ring; 121. Annular boss; 13. Upper double ring body; 14. Lower double ring body; 2. Stationary ring; 3. Housing; 4. Grinding disc tray; 5. Support ring; 6. Bracket; 7. First guide vane; 8. Second guide vane; 9. First connector; 10. Second connector; 15. Mounting hole. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0036] In the description of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. The terms "connected," "linked," and "set up" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0037] Figure 4 This is a schematic diagram of a conventional nozzle ring, where 1 is the moving ring, 2 is the stationary ring, and 3 indicates the vertical gap formed by the moving ring 1 and the stationary ring 2. The flow channel inside the moving ring 1 is vertically arranged.

[0038] Please see Figure 1-2 This utility model provides the following technical solution: a rotating ring for a nozzle device. Specifically, the rotating ring 1 (also called a nozzle, or nozzle rotating ring) has an inner air ring 11 and an outer air ring 12. The inner air ring 11 is used to be mounted on the grinding disc tray 4 via a first connecting member 9 (such as a bolt and nut), so that the grinding disc tray 4 can rotate with the inner air ring 11 during operation. The outer air ring 12 is sleeved on the circumferential outer side of the inner air ring 11, and a gap is formed between the outer air ring 12 and the inner air ring 11 in the direction from bottom to top (e.g., Figure 1The flow channel shown (from bottom to top, i.e., the direction from the primary air inlet to the primary air outlet) remains unchanged after reduction. The cavity wall of the flow channel is formed by the outer wall of the inner air ring 11 (the side away from the grinding disc tray 4) and the inner wall of the outer air ring 12 (the side closer to the grinding disc tray 4). The flow channel is deflected relative to the vertical direction towards the axis of the inner air ring 11. The flow channel shape is designed as streamlined according to fluid dynamics. Based on the fundamentals of fluid dynamics, local resistance is inversely proportional to the flow area (e.g., the larger the flow area, the greater the resistance). The smaller the local resistance, the more efficient the design of the streamlined opening (inlet) can be, thus increasing the average flow area of ​​the nozzle domain. Local resistance is directly proportional to the characteristic length of the nozzle (e.g., the shorter the nozzle, the smaller the local resistance), effectively reducing the local fluid (fluid in this article refers to the air-powder flow, also known as primary air) resistance in the nozzle. The upper part of the flow channel adopts a reduced flow channel design with an inward-curving angle. This design can reduce the local resistance of the entire dynamic ring without reducing the flow channel performance, increase the primary air diffusion area at the outlet, and effectively reduce the wear of the casing 3. In addition, compared to Figure 4 In the conventional nozzle ring shown, the flow channel within the moving ring 1 has a shorter characteristic length in terms of hydrodynamics, resulting in reduced resistance. Guide vanes are arranged within the flow channel, connecting the inner air ring 11 and the outer air ring 12. This allows the outer air ring 12 to be fitted around the circumferential outer side of the inner air ring 11 via the guide vanes. Several guide vanes are evenly and obliquely distributed between the inner and outer air rings 11 and 12 along the circumference of either the inner or outer air ring 12. For example, the guide vanes are at a 15° angle to the horizontal plane. The guide vanes evenly divide the flow channel into multiple primary air inlet paths. Each primary air inlet path has a primary air inlet at the bottom and a primary air outlet at the top. When the inner air ring 11 rotates, it simultaneously drives the outer air ring 12 to rotate via the guide vanes, forming primary airflow. The primary airflow flows from the primary air inlet to the primary air outlet within the primary air inlet path in an upward direction, meaning the primary airflow moves from bottom to top along the flow channel. Preferably, the outer air ring 12 and the inner air ring 11 are staggered vertically, that is, in Figure 1 In the image shown, the top height of the outer air ring 12 is higher than the top height of the inner air ring 11, and the bottom height of the outer air ring 12 is higher than the bottom height of the inner air ring 11. This design, derived through simulation optimization, effectively reduces local resistance and deflects the primary airflow within the channel towards a relatively vertical direction, closer to the grinding disc, thus increasing the primary air's powder-carrying capacity. Furthermore, both the outer wall of the inner air ring 11 and the inner wall of the outer air ring 12 are smooth surfaces, which helps reduce wind resistance. This application optimizes the original nozzle ring through finite element simulation analysis, reducing the local resistance of the moving ring 1 and solving the problem of rapid wear of the moving ring 1 under the action of the air-powder flow. It should be noted that the characteristic length is the ratio of area (the axial cross-sectional area of ​​the flow domain) to perimeter (the wetting perimeter of the cross-section) in fluid mechanics. A certain cross-sectional area of ​​the flow domain corresponds to a certain characteristic length of the cross-section, which can be obtained through calculation.

[0039] This application abandons the blades (in the form of "straight segments plus commas") in the conventional nozzle ring. Instead, multiple layers (two or more layers, the specific number of which is determined by the number of segments of the double ring body) of guide blades are arranged in the flow channel from bottom to top to interrupt the length of the flow channel. While ensuring the performance of the flow channel, the characteristic length of the flow channel is effectively reduced, thereby effectively reducing the local resistance of the flow channel.

[0040] As a specific structural embodiment of the aforementioned air duct profile, in this embodiment, in the top-to-bottom direction, the inner wall of the outer air ring 12 adopts a combination of straight lines and spline curves. The top to 1 / 5 to 1 / 3 of the inner wall of the outer air ring 12 (characteristic length) is a straight line at an angle of 10° to 20° with the vertical direction, and the 1 / 5 to 1 / 3 of the inner wall of the outer air ring 12 to the bottom (characteristic length) is a spline curve curving from the inside to the outside, with the center of curvature located outside the flow channel. In the top-to-bottom direction, the outer wall of the inner air ring 11 adopts a combination of straight lines and spline curves. The top to 1 / 5 to 1 / 3 of the outer wall of the inner air ring 11 (characteristic length) is a straight line at an angle of 10° to 20° with the vertical direction, and the 1 / 5 to 1 / 3 of the outer wall of the inner air ring 11 to the bottom is a spline curve curving from the inside to the outside, with the center of curvature located outside the flow channel. (Refer to...) Figure 1 The diagram shows a longitudinal cross-section of the flow channel formed by the inner wall of the outer air ring 12 and the outer wall of the inner air ring 11. The moving ring 1 (which can also be understood as the linear shape of the flow channel) has a converging structure. The design of the inner wall of the outer air ring 12 and the outer wall of the inner air ring 11 helps to reduce local resistance within the flow channel. It should be noted that the upper part of the inner wall of the outer air ring 12 and the upper part of the outer wall of the inner air ring 11 form an inward-curving angle in the flow channel.

[0041] As an embodiment of the specific structure of the aforementioned guide vane, in this embodiment, the guide vane adopts a combination of straight lines and spline curves in the top-to-bottom direction. Figure 3 In the image shown, the top to 1 / 4 to 1 / 3 of the guide vane (characteristic length) is a straight line with an angle of 40° to 50° (e.g., 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, with 45° being optimal) to the horizontal plane. The section from 1 / 4 to 1 / 3 of the guide vane to the bottom (characteristic length) is a spline curve, and the angle between the bottom tangent of the spline curve and the vertical direction is 0° to 15°, for example: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, which helps to reduce wind resistance.

[0042] To address the difficulty of maintaining the blades (which have a "straight section plus comma" structure) in conventional nozzle rings, the moving ring 1 of this application adopts a split upper and lower design, consisting of two or more double-ring sections. The specific number of double-ring sections can be flexibly set according to actual needs, as described in the reference. Figure 1 As shown, taking a moving ring 1 composed of two double-ring bodies as an example, the moving ring 1 consists of an upper double-ring body 13 and a lower double-ring body 14. The upper double-ring body 13 and the lower double-ring body 14 are detachably connected. The upper end of the lower double-ring body 14 has an annular groove (also called a stop) spanning both sides of the flow channel. The annular groove is used to support the upper double-ring body 13, meaning the upper and lower parts of the moving ring 1 are connected by an embedded connection. Both the upper double-ring body 13 and the lower double-ring body 14 have mounting holes 15 for clearance fit. The lower double-ring body 14 and the upper double-ring body 13 are connected together at the stop by bolts, nuts, or screws, which shortens the maintenance period and reduces maintenance intensity. Regarding the criteria for dividing the upper and lower parts of the moving ring 1, in the direction from top to bottom, the top to 1 / 4 to 1 / 2 of the characteristic length of the moving ring 1 is the upper part of the moving ring 1, and the 1 / 4 to 1 / 2 of the characteristic length of the moving ring 1 is the lower part of the moving ring 1. The upper part of the moving ring 1 can also be simply understood as the entire upper double ring body 13 and part of the lower double ring body 14 (e.g., Figure 1The combination of the lower part of the mounting hole 15 in the lower double ring body 14 area shown in the image can be flexibly adjusted according to the actual situation during processing and production, taking into account the connection method between the two. It is worth mentioning that both the upper double ring body 13 and the lower double ring body 14 are also provided with guide vanes at different heights. For easy distinction, we refer to the guide vane located in the upper double ring body 13 as the first guide vane 7, and the guide vane located in the lower double ring body 14 as the second guide vane 8. That is, the upper double ring body 13 is formed by connecting the upper part of the inner wind ring 11 and the upper part of the outer wind ring 12 through the first guide vane 7. The lower double ring body 14 is formed by connecting the lower part of the inner wind ring 11 and the lower part of the outer wind ring 12 through the second guide vane 8. The moving ring 1 is composed of multiple segments spliced ​​together along its axis to form a complete ring structure. The upper double ring 13 is divided into more than 10 segments, each secured with bolts and nuts. The lower double ring 14 can be composed of a single ring or multiple segments; if composed of multiple segments, the joints are fully welded together. It should be noted that the inner cavities of the upper double ring 13 and the lower double ring 14 constitute the entire flow channel, and the gas flow channels are interconnected at the junction of the upper and lower double ring 13 and 14. Furthermore, since the upper part of the moving ring 1 is the main wear area during operation, the upper double ring 13 is made of wear-resistant materials (such as ZG50Mn2, high-chromium cast iron, and NM series materials). The first guide vane 7 and the second guide vane 8 have the same structure, differing only in their position within the flow channel and the angle between them and the horizontal plane. Preferably, the angle between the first guide vane 7 located in the flow channel within the upper double ring body 13 and the horizontal plane is 10-15°, for example: 10°, 11°, 12°, 13°, 14°, 15°; and the angle between the second guide vane 8 located in the flow channel within the lower double ring body 14 and the horizontal plane is 15-25°, for example: 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°.

[0043] Reference Figure 1 The streamlined moving ring 1 shown has an upper inner wall of the outer air ring 12 that is straight, and a lower inner wall that is curved from the inside out. Similarly, the upper outer wall of the inner air ring 11 is straight, and the lower outer wall is curved from the inside out, which facilitates the flow of primary air. Preferably, the inlet flow area of ​​the flow channel is more than three times the outlet flow area, thus shortening the characteristic length of the flow channel.

[0044] Reference Figure 3As shown, this utility model also provides the following technical solution: A nozzle device includes a rotating ring 1 and a stationary ring 2. Specifically, the rotating ring 1 is the rotating ring for the nozzle device described above. During installation, the stationary ring 2 is located above the rotating ring 1, and the stationary ring 2 is connected to the housing 3 via a support ring 5. For example, the stationary ring 2 is detachably connected to the support ring 5 via a second connecting member 10 (such as a bolt, nut, or screw). The support ring 5 is located below the stationary ring 2 and is used to support the stationary ring 2. A bracket 6 is provided below the support ring 5, and the bracket 6 is welded to the housing 3. The bracket 6 is used to support the support ring 5. The support ring 5 and the housing 3 are sealed together, for example, by welding round steel to seal the connection between the support ring 5 and the housing 3. Preferably, both the stationary ring 2 and the support ring 5 are manufactured and installed in sections. The inner wall of the stationary ring 2 is aligned with the inner wall of the outer air ring 12. For example, the inner wall of the outer air ring 12 is a straight line with an angle of 10° to 20° with the vertical direction, which can guide the primary airflow to the middle of the coal mill.

[0045] To improve the sealing performance of the nozzle device, in this embodiment, the outer side wall at the upper end of the outer air ring 12 extends radially outward to form an annular boss 121 (i.e., a section of horizontal plane), and the width of the annular boss 121 (within...) Figure 1 In the image shown, the distance from left to right is 40-100 mm. There is a horizontal (fitting) gap of 5-10 mm between the upper end of the annular boss 121 and the stationary ring 2 extending inward (towards the grinding disc tray 4), for example: 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm. The vertical (fitting) gap between the annular boss 121 and the support ring 5 is 8-20 mm, for example: 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm. In other words, the dynamic and static gaps between the dynamic ring 1 and the stationary ring 2 are sealed by a combination of horizontal and vertical gaps (we call this a labyrinth seal), which reduces primary air loss.

[0046] As is known from common technical knowledge, this utility model can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

Claims

1. A rotating ring for a nozzle assembly, characterized in that, The moving ring has an inner air ring and an outer air ring. The inner air ring is used to install on the grinding disc tray. The outer air ring is sleeved on the circumferential outer side of the inner air ring and forms a flow channel between the outer and inner air rings that gradually narrows from bottom to top and remains unchanged. The flow channel is deflected relative to the vertical direction toward the axis of the inner air ring, and guide vanes are arranged in the flow channel.

2. The moving ring for the nozzle device according to claim 1, characterized in that, The height of the top of the outer wind ring is higher than the height of the top of the inner wind ring, and the height of the bottom of the outer wind ring is higher than the height of the bottom of the inner wind ring.

3. The moving ring for the nozzle device according to claim 1, characterized in that, In the direction from bottom to top, multiple layers of the guide vanes are spaced apart in the flow channel to reduce the characteristic length of the flow channel.

4. The moving ring for the nozzle device according to claim 1, characterized in that, In the direction from top to bottom, the top to 1 / 5 to 1 / 3 of the inner wall of the outer wind ring is a straight line with an angle of 10° to 20° to the vertical direction, and the bottom of the 1 / 5 to 1 / 3 of the inner wall of the outer wind ring is a spline curve that curves from the inside to the outside. In the direction from top to bottom, the top to 1 / 5 to 1 / 3 of the outer wall of the inner wind ring is a straight line with an angle of 10° to 20° to the vertical direction, and the bottom of the 1 / 5 to 1 / 3 of the outer wall of the inner wind ring is a spline curve that curves from the inside to the outside. A primary airflow moves from bottom to top along the channel.

5. The moving ring for the nozzle device according to claim 1, characterized in that, In the top-to-bottom direction, the top to 1 / 4 to 1 / 3 of the guide vane is a straight line with an angle of 40° to 50° with the horizontal plane, and the 1 / 4 to 1 / 3 of the guide vane to the bottom 3 / 4 is a spline curve, and the angle between the bottom tangent of the spline curve and the vertical direction is 0° to 15°.

6. The moving ring for the nozzle device according to claim 1, characterized in that, The moving ring is composed of an upper double-ring body and a lower double-ring body; The upper end of the lower double ring body is provided with an annular groove that spans both sides of the flow channel, for supporting the upper double ring body; The upper double ring and the lower double ring are detachably connected; and The upper double ring is made of wear-resistant material.

7. The moving ring for the nozzle device according to claim 6, characterized in that, A first guide vane is arranged in the flow channel located in the upper double ring body, and the angle between the first guide vane and the horizontal plane is 10-15°. A second guide vane is arranged in the flow channel located in the lower double ring body, and the angle between the second guide vane and the horizontal plane is 15-25°.

8. The moving ring for the nozzle device according to claim 1, characterized in that, The outer side wall at the upper end of the outer wind ring extends radially outward to form an annular protrusion.

9. A nozzle device located inside the casing of a coal mill, characterized in that, The nozzle device includes: The rotating ring is the rotating ring for the nozzle device according to any one of claims 1-8; A stationary ring, located above the rotating ring, is connected to the housing via a support ring; The profile of the inner wall of the static ring matches the profile of the inner wall of the outer air ring.

10. The nozzle device according to claim 9, characterized in that, The outer side wall at the upper end of the outer wind ring extends radially outward to form an annular protrusion; A horizontal gap of 5 to 10 mm is formed between the top of the annular boss and the stationary ring; A vertical gap of 8 to 20 mm is formed between the outer wall of the annular boss and the support ring.

Images