High-uniformity low-energy-consumption static nozzle ring device

Abstract

The invention relates to the technical field of coal mills, and discloses a high-uniformity low-energy-consumption static nozzle ring device which comprises a nozzle ring, a wear-resistant block and a pressing and blocking piece. The nozzle ring is fixed in the machine shell, the nozzle ring and a millstone supporting ring in the machine shell are coaxially arranged, a through-flow area of the nozzle ring is provided with a first airflow channel, a second airflow channel and a third airflow channel which are sequentially communicated from bottom to top, and a plurality of first blades are arranged in the second airflow channel to divide the second airflow channel into a plurality of first nozzles. The through-flow area of the first nozzle is gradually increased from the position close to the primary air outlet to the position far away from the primary air outlet; and the wear-resistant block is limited in the third airflow channel of the nozzle ring through the pressing and blocking piece. The airflow velocity distribution of a through-flow area is simulated through an experiment, and the through-flow area of a runner is adjusted by using a spline curve, so that the flow velocity of a flow field in a whole nozzle ring area is more uniform, the abrasion condition of an abrasion-resistant block and a machine shell is effectively improved, and the overall service life is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of coal mills, in particular to a high-uniformity and low-energy-consumption static nozzle ring device. Background Art

[0002] Coal mill has the advantages of low noise, low power consumption, small footprint and compact equipment. It is widely used in power generation, chemical industry, metallurgical industry, etc. The ZGM coal mill designed by Beijing Electric Power Equipment General Plant and the coal mill designed by Changchun Power Generation Equipment Co., Ltd. are more common in the market. At this stage, the conventional design of the nozzle circulation channel has the same upper and lower flow areas. The nozzle ring handle is combined with the grinding disc support ring and rotates with the grinding disc support ring, also known as a rotating nozzle ring. The conventional rotating nozzle ring has the advantage of uniform wear, but the rotating nozzle ring cannot solve the uneven nozzle circulation field caused by the asymmetry of the primary air. Multiple on-site feedback showed that the casing wear plate on the right side of the coal mill near the primary air inlet was severely damaged. In severe cases, the inner wall of the casing was even worn through in a short period of time, causing serious losses. Summary of the invention

[0003] The object of the present invention is to provide a high-uniformity and low-energy-consumption stationary nozzle ring device to solve the problems of uneven annular flow field of conventional rotating nozzles in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A high uniformity and low energy consumption stationary nozzle ring device, comprising:

[0006] A nozzle ring, the nozzle ring is fixed inside the housing, the nozzle ring is coaxially arranged with the grinding disc support ring inside the housing, and is located on the outside of the grinding disc support ring, the flow area of ​​the nozzle ring has a first airflow channel, a second airflow channel and a third airflow channel which are sequentially connected from bottom to top, a plurality of first blades are arranged in the second airflow channel, and the plurality of first blades are spaced apart along the circumferential direction of the nozzle ring to separate the second airflow channel into a plurality of first nozzles, and the flow area of ​​the first nozzle gradually increases from close to the primary air outlet to far away from the primary air outlet;

[0007] A wear-resistant block, wherein the wear-resistant block is detachably embedded in the third air flow channel of the nozzle ring, the wear-resistant block is located on the outer side of the grinding disc support ring, the flow area of ​​the wear-resistant block is separated into second nozzles corresponding to the first nozzles by the second blade, each group of mutually corresponding first nozzles and second nozzles are interconnected, the flow areas of the second nozzles are equal, and the primary air flow is ejected after passing through the first air flow channel, the first nozzle and the second nozzle in sequence;

[0008] The pressure block includes a first pressure ring and a second pressure ring; the first pressure ring is detachably mounted on the nozzle ring and abuts against the outer wall of the wear-resistant block to limit the wear-resistant block within the third airflow channel of the nozzle ring, and the second pressure ring is detachably mounted on the grinding disc support ring and is in dynamic friction contact with the inner wall of the wear-resistant block. This setting is used to adjust the flow area of ​​each second nozzle on the circumference of the nozzle ring, the high-speed area of ​​the nozzle ring is adjusted downward, and the low-speed area of ​​the nozzle ring is compensated upward, so that the flow field velocity of the entire nozzle ring area is more uniform, and the nozzle ring device has the characteristics of low resistance and high uniformity. In addition, the wear-resistant block is designed to be replaceable, which reduces maintenance costs and manufacturing costs.

[0009] Furthermore, the opening sizes of each of the first nozzles along the circumferential direction of the nozzle ring are the same, and the opening sizes of each of the first nozzles along the radial direction of the nozzle ring gradually increase from close to the primary air outlet to far away from the primary air outlet. Through this arrangement, the thickness of the first blade remains unchanged during the process of adjusting the flow area of ​​the first nozzle, which facilitates the determination of the thickness of the second blade and the docking of the second blade with the first blade.

[0010] Furthermore, the maximum flow area of ​​the plurality of first nozzles is 1.5 to 2.5 times the minimum flow area. This data is obtained based on software simulation.

[0011] Further, the nozzle ring includes an outer upper guard plate, an outer lower guard plate and an inner lower guard plate; the outer upper guard plate is located at the upper end of the outer lower guard plate, the inner lower guard plate is located on the inner side of the outer lower guard plate and is arranged at intervals, so that a first airflow channel and a second airflow channel distributed from bottom to top are formed between the outer lower guard plate and the inner lower guard plate, the inner area of ​​the first end of the outer upper guard plate is a third airflow channel, the second end of the outer upper guard plate is fixedly connected to the inner wall of the casing, and the bottom end of the outer lower guard plate is fixedly connected to the casing. The nozzle ring is composed of multiple parts, which is convenient for streamlining its inner wall and reducing airflow resistance.

[0012] Furthermore, the outer upper guard plate includes an oblique guard plate and an annular expansion plate; the first end of the annular expansion plate is connected to the oblique guard plate, the second end of the annular expansion plate is fixedly connected to the inner wall of the casing, the oblique guard plate is connected to the outer lower guard plate, the inner side of the oblique guard plate is a third airflow channel, and the oblique guard plate has an angle of 10° to 20° with the vertical direction, preferably 15°. Through this arrangement, the nozzle ring can be fixed in the casing, and the oblique guard plate can effectively reduce the airflow resistance.

[0013] Furthermore, it also includes an annular support plate, which is fixed to the inner wall of the casing, and the outer lower guard plate is fixedly connected to the casing through the annular support plate.

[0014] Furthermore, the wear-resistant block includes an inner guard plate and an outer guard plate; the inner guard plate is located on the inner side of the outer guard plate and is arranged at intervals to form a flow area of ​​the wear-resistant block, the second blade is located between the inner guard plate and the outer guard plate, the inner guard plate is in dynamic friction contact with the second pressure ring, the outer guard plate is in contact with the first pressure ring, and when the wear-resistant block is embedded in the third airflow channel, the inner guard plate is docked with the inner lower guard plate to form the inner wall of the flow channel, the second blade is docked with the first blade to form a guide blade, and the outer guard plate is docked with the outer lower guard plate to form the outer wall of the flow channel. The inner guard plate and the inner lower guard plate, the outer guard plate and the outer lower guard plate, and the second blade and the first blade are seamlessly connected, which effectively reduces airflow loss and reduces airflow resistance.

[0015] Furthermore, when the wear-resistant block is embedded in the third air flow channel, the edge line of the longitudinal section of the inner wall of the flow channel is a combination of a straight line and a spline curve from top to bottom, the upper 1 / 4 section is a straight line at 10° to 20° to the vertical direction, and the upper 1 / 4 to the bottom is a spline curve, and the center of the curvature is all outside the flow area. This setting conforms to the fluid dynamics design, effectively alleviates fluid turbulence, and reduces fluid pressure loss.

[0016] Furthermore, when the wear-resistant block is embedded in the third air flow channel, the edge line of the longitudinal section of the outer wall of the flow channel is a combination of a straight line and a spline curve from top to bottom, the upper 1 / 5 section is a straight line at 10° to 20° to the vertical direction, the upper 1 / 5 to the bottom is a spline curve, and the center of curvature is all outside the flow area. This setting conforms to the fluid dynamics design, effectively alleviates fluid turbulence, and reduces fluid pressure loss.

[0017] Furthermore, when the wear-resistant block is embedded in the third air flow channel, the edge line where the guide blade contacts the outer wall of the flow channel is a combination of a straight line and a spline curve from top to bottom, the upper 1 / 4 section is a straight line at 40° to 50° with the horizontal direction, the upper 1 / 4 to the bottom is a spline curve, and the angle between the bottom tangent direction and the vertical direction is 0° to 15°. This setting conforms to the fluid dynamics design, effectively alleviates fluid turbulence, and reduces fluid pressure loss.

[0018] Furthermore, the inner guard plate and the outer guard plate each have an angle of 10° to 20° with the vertical direction, preferably 15°. With this arrangement, the inner guard plate, the outer guard plate and the oblique guard plate have the same inclination angle, which facilitates the installation of the wear-resistant block in the third air flow channel.

[0019] Furthermore, the first pressure ring is arranged in close contact with the annular expansion plate, the outer top of the outer guard plate has a chamfered surface, the first end of the first pressure ring abuts against the chamfered surface of the outer guard plate, the second end of the first pressure ring abuts against the inner wall of the casing, and the first pressure ring and the annular expansion plate are connected by bolts. This arrangement can effectively prevent the wear-resistant block from deviating during rotation.

[0020] Furthermore, the upper side of the second blade is a slope of 0° to 30°, and the side of the upper side of the second blade close to the inner guard plate is lower than the side close to the outer guard plate. This setting can optimize the force distribution of the wear-resistant block and effectively reduce the stress concentration of the wear-resistant block.

[0021] Furthermore, the height of the inner guard plate in the vertical direction is lower than that of the outer guard plate, and the height of the outer guard plate is higher than that of the second blade. This arrangement can effectively reduce the ventilation resistance of the nozzle ring on the basis of the opening.

[0022] The present invention has the following advantages over the prior art:

[0023] 1. The high-uniformity, low-energy-consumption static nozzle ring device of the present invention fixes the nozzle ring on the casing of the coal mill. The nozzle ring does not rotate with the grinding disc support ring, which effectively reduces power consumption during operation and saves operating costs. Due to the asymmetry of the primary air duct, the gas flow rate in the flow area of ​​the nozzle ring is different, which leads to different degrees of wear at different positions. The nozzle ring adjusts the flow area of ​​each first nozzle on the circumference of the nozzle ring, and the flow area of ​​the first nozzle gradually increases from close to the primary air outlet to far away from the primary air outlet, making the flow field velocity of the entire nozzle ring area more uniform, making the nozzle ring have high uniformity, effectively improving the wear of the wear-resistant block and the casing, and improving the overall service life.

[0024] 2. A replaceable wear-resistant block is provided in the high-uniformity and low-energy consumption stationary nozzle ring device of the present invention. Experiments have shown that the wear of the nozzle ring is caused by the long-term impact of coal powder particles in the airflow on the metal surface. A large number of practices have shown that when the airflow passes through the lower part of the nozzle ring (the first airflow channel and the second airflow channel), there are no coal powder particles in the airflow and no wear will occur during the operation. Therefore, during the operation, the wear area is mainly distributed in the upper half of the entire flow channel (the third airflow channel). Therefore, a replaceable wear-resistant block is designed in the third airflow channel. When wear occurs during the operation of the coal mill, there is no need to replace the entire nozzle ring, but only the wear-resistant block, thereby reducing maintenance costs and manufacturing costs.

[0025] 3. The high uniformity and low energy consumption static nozzle ring device of the present invention adopts the combination of straight lines and spline curves to design the inner walls of the first airflow channel, the second airflow channel and the third airflow channel. Compared with the inner wall of the straight-cylindrical flow area in the prior art, the device can effectively reduce the local resistance of the nozzle ring and reduce wear. The upper outer wall of the nozzle ring in the present invention is an annular expansion plate. The airflow flows in from the bottom of the nozzle ring and flows out from the top of the wear-resistant block, which effectively increases the gas diffusion area at the outlet of the wear-resistant block and effectively reduces the wear of the casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1It is a longitudinal cross-sectional schematic diagram of the high uniformity and low energy consumption stationary nozzle ring device and the grinding disc support ring in the embodiment of the present invention;

[0027] Figure 2 A longitudinal cross-sectional schematic diagram of a high uniformity and low energy consumption stationary nozzle ring device in an embodiment of the present invention;

[0028] Figure 3 is a schematic cross-sectional view of a second air flow channel of a nozzle ring in a high-uniformity, low-energy-consumption stationary nozzle ring device in an embodiment of the present invention;

[0029] Figure 4 Schematic diagram of the structure of the guide vanes in the high uniformity and low energy consumption stationary nozzle ring device in an embodiment of the present invention.

[0030] In the figure: 1. nozzle ring; 101. first air flow channel; 102. second air flow channel; 103. third air flow channel; 104. first blade; 105. first nozzle; 106. outer lower guard plate; 107. inner lower guard plate; 108. oblique guard plate; 109. annular expansion plate; 2. casing; 3. grinding disc support ring; 4. wear-resistant block; 401. second blade; 402. inner guard plate; 4021. limiting right angle; 403. outer guard plate; 4031. beveled surface; 4032. cut angle; 5. first pressure ring; 6. second pressure ring; 7. annular support plate; 8. bolt; 9. low resistance area; 10. high resistance area. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0033] In addition, it should be understood that for the convenience of description, the sizes of various components shown in the drawings are not drawn according to the actual proportional relationship.

[0034] It should be noted that like reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not need to be further discussed and described in detail in the description of the subsequent drawings.

[0035] Example:

[0036] like Figure 1 and Figure 2 As shown, a high uniformity and low energy consumption stationary nozzle ring device comprises:

[0037] A nozzle ring 1, wherein the nozzle ring 1 is fixed inside the housing 2, the nozzle ring 1 is coaxially arranged with the grinding disc support ring 3 inside the housing 2, and is located on the outside of the grinding disc support ring 3, the flow area of ​​the nozzle ring 1 has a first airflow channel 101, a second airflow channel 102 and a third airflow channel 103 which are sequentially connected from bottom to top, a plurality of first blades 104 are arranged in the second airflow channel 102, and a plurality of the first blades 104 are spaced apart along the circumferential direction of the nozzle ring 1 to separate the second airflow channel 102 into a plurality of first nozzles 105, and the flow area of ​​the first nozzle 105 gradually increases from close to the primary air outlet to far away from the primary air outlet;

[0038] Preferably, if Figure 3 As shown, the opening size of each of the first nozzles 105 along the circumferential direction of the nozzle ring 1 is the same, and the opening size of each of the first nozzles 105 along the radial direction of the nozzle ring 1 gradually increases from close to the primary air outlet to far away from the primary air outlet. By adjusting the radial size of the first nozzle 105 along the nozzle ring 1, the flow area of ​​the first nozzle 105 is gradually increased from close to the primary air outlet to far away from the primary air outlet, so that the flow field velocity of the entire nozzle ring area is more uniform, and the nozzle ring has high uniformity, which effectively improves the wear of the wear-resistant block and the casing and improves the overall service life. In this implementation, the radial opening size is adjusted instead of the circumferential opening size, so as to achieve the uniformity of the thickness of each first blade and facilitate docking with the second blade. Among them, according to software simulation, the maximum flow area among several first nozzles is 1.5 to 2.5 times the minimum flow area.

[0039] The wear-resistant block 4 is detachably embedded in the third air flow channel 103 of the nozzle ring 1. The wear-resistant block 4 is located on the outer side of the grinding disc support ring 3. The flow area of ​​the wear-resistant block 4 is separated into second nozzles corresponding to the first nozzles 105 by the second blade 401. Each group of corresponding first nozzles 105 and second nozzles are interconnected, and the flow areas of the second nozzles are equal. The primary air flow passes through the first air flow channel 101, the first nozzle 105 and the second nozzle in sequence and is ejected. The flow area of ​​each first nozzle 105 is adjusted to make the air flow velocity at the outlet of each second nozzle in the circumferential direction of the nozzle ring 1 more uniform.

[0040] The pressure stopper comprises a first pressure ring 5 and a second pressure ring 6; the first pressure ring 5 is detachably mounted on the nozzle ring 1 and abuts against the outer wall of the wear-resistant block 4 to limit the wear-resistant block 4 in the third airflow channel 103 of the nozzle ring 1, and the second pressure ring 6 is detachably mounted on the grinding disc support ring 4 and is in dynamic friction contact with the inner wall of the wear-resistant block 4. By setting the first pressure ring 5 and the second pressure ring 6, the replaceable design of the wear-resistant block 4 can be realized, and at the same time, the stability of the wear-resistant block 4 embedded in the third airflow channel 103 can be improved. The second pressure ring 6 also has a height compensation effect. The outer wall edge line of the second pressure ring 6 is connected to the inner wall edge line of the inner guard plate 402 of the wear-resistant block up and down, and the setting of the second pressure ring 6 does not change the outlet size of the second nozzle. The horizontal gap between the top of the inner guard plate 402 of the wear-resistant block 4 and the second pressure ring 6 is in dynamic sealing contact, and the vertical gap between the outer side of the inner guard plate 402 and the grinding disc support ring 3 is in dynamic sealing contact.

[0041] The wear-resistant block 4 is made of wear-resistant material and is replaceable. The overall flow channel of the nozzle ring 1 adopts a streamlined design that conforms to fluid dynamics. Due to the asymmetry of the primary air duct, during actual operation, at different positions on the circumference, the gas flow rates inside each channel on the cross-section of the nozzle ring are different, resulting in different degrees of casing wear at different positions. To solve this problem, the nozzle ring 1 in the present invention uses a spline curve to adjust the air flow velocity on different curves (different positions) on the circumference, and the internal flow channel of the wear-resistant block is connected to the flow channel of the nozzle ring. Since the nozzle ring is changed to a static opening structure, the nozzle has the characteristics of low resistance, high uniformity, replaceability and low power consumption.

[0042] The nozzle ring 1 in the present invention determines the velocity distribution of the entire flow area through numerical simulation, and uses a spline curve to adjust the flow area of ​​the flow channel according to the different speeds of each flow channel. The gas flow rate is based on the outlet of the wear-resistant block. The high-speed area of ​​the nozzle ring is adjusted downward (reducing the flow area), and the low-speed area of ​​the nozzle ring is compensated upward (increasing the flow area), so that the flow velocity of the flow field in the entire nozzle ring area is more uniform (the wind speed at the outlet of the second nozzle is uniform); this nozzle ring is designed with a wear-resistant block, and the wear-resistant block is made of wear-resistant material. The wear of the nozzle ring is caused by the long-term impact of coal powder particles in the airflow on the metal surface. A large number of practices have shown that when the airflow passes through the lower part of the nozzle ring, there are no coal powder particles in the airflow, and no wear will occur during the operation. Therefore, during the operation, the wear area is mainly distributed in the upper half of the entire flow channel. Therefore, this solution designs replaceable wear-resistant blocks. When wear occurs during the operation of the coal mill, there is no need to replace the entire nozzle ring, only the wear-resistant blocks need to be replaced, thereby reducing maintenance costs and manufacturing costs.

[0043] like Figure 2As shown, the nozzle ring 1 includes an outer upper guard plate, an outer lower guard plate 106 and an inner lower guard plate 107; the outer upper guard plate is located at the upper end of the outer lower guard plate 106, and the inner lower guard plate 107 is located on the inner side of the outer lower guard plate 106 and is arranged at intervals, so that a first airflow channel 101 and a second airflow channel 102 distributed from bottom to top are formed between the outer lower guard plate 106 and the inner lower guard plate 107, and the inner area of ​​the first end of the outer upper guard plate is a third airflow channel 103, the second end of the outer upper guard plate is fixedly connected to the inner wall of the casing 2, and the bottom end of the outer lower guard plate 106 is fixedly connected to the casing 2. Specifically, the inner wall of the casing 2 is welded with an annular support plate 7, and the bottom end of the outer lower guard plate 106 is fixedly connected to the casing 2 through the annular support plate 7. Through this arrangement, the nozzle ring 1 can be fixed in the housing so that it presents a static opening design. The inner walls of the first airflow channel 101, the second airflow channel 102 and the third airflow channel 103 adopt a streamlined design to effectively reduce airflow resistance.

[0044] In this embodiment, the outer upper guard plate includes an oblique guard plate 108 and an annular expansion plate 109; the first end of the annular expansion plate 109 is connected to the oblique guard plate 108, and the second end of the annular expansion plate 109 is fixedly connected to the inner wall of the casing 2, the oblique guard plate 108 is connected to the outer lower guard plate 106, and the inner side of the oblique guard plate 108 is a third air flow channel, and the oblique guard plate 108 has an angle of 10° to 20° with the vertical direction, preferably 15°.

[0045] According to the structural design of the outer upper guard plate, the wear-resistant block 4 is set as a combination of an inner guard plate 402 and an outer guard plate 403; the inner guard plate 402 is located on the inner side of the outer guard plate 403 and is arranged at intervals to form a flow area of ​​the wear-resistant block 4, and the second blade 401 is located between the inner guard plate 402 and the outer guard plate 403. When the wear-resistant block 4 is embedded in the third air flow channel 103, the first pressure ring 5 is arranged along the annular expansion plate 109 and is fixed on the annular expansion plate 109 by bolts. The first pressure ring The bottom of 5 abuts against the outer guard plate 403, thereby limiting the wear-resistant block 4 in the third air flow channel 103, the inner guard plate 402 is in dynamic friction contact with the second pressure ring 6, the outer guard plate 403 is fitted with the oblique guard plate 108, and the two have the same inclination angle, the inner guard plate 402 is connected with the inner lower guard plate 107 to form the inner wall of the flow channel, the second blade 401 is connected with the first blade 104 to form a guide blade, and the outer guard plate 403 is connected with the outer lower guard plate 106 to form the outer wall of the flow channel.

[0046] In this embodiment, in order to facilitate the placement of the wear-resistant block 4 into the third air flow channel 103, a cut angle 4032 is set along a vertical direction at the bottom of the outer guard plate 403 of the wear-resistant block 4, and a limiting right angle 4021 is designed on the outer side of the bottom of the inner guard plate 402 of the wear-resistant block. This limiting right angle 4021 and the top of the lower inner guard plate 107 of the nozzle ring serve as a mating surface.

[0047] At the same time, in order to better fix the wear-resistant block 4, the outer side of the top end of the outer guard plate 403 has a bevel surface 4031, and the first end of the first pressure ring 5 abuts against the bevel surface 4031 of the outer guard plate 403. The angle of the bevel surface is 30° to 50°, and preferably 40° in this embodiment.

[0048] Specifically, the upper side of the second blade 401 is an inclined surface with an angle of 0° to 30°, and the side of the upper side of the second blade 401 close to the inner guard plate 402 is lower than the side close to the outer guard plate 403. This setting can optimize the force distribution of the wear-resistant block and effectively reduce the stress concentration of the wear-resistant block. The gas outlet direction of the wear-resistant block flow channel is perpendicular to the outlet cross section, so that the wear-resistant block wears evenly during operation.

[0049] The height of the inner guard plate in the vertical direction is lower than that of the outer guard plate, and the height of the outer guard plate is higher than that of the second blade. The second pressure ring 6 is provided to compensate the height of the inner guard plate, and this arrangement increases the length of the air leakage channel between the nozzle ring and the grinding disc tray, which can effectively reduce the air leakage volume.

[0050] In this embodiment, the inner wall of the nozzle ring flow area is adjusted to be streamlined specifically as follows:

[0051] When the wear-resistant block 4 is embedded in the third air flow channel 103, the inner guard plate 402 is connected to the inner lower guard plate 107 to form the inner wall of the flow channel. The edge line of the longitudinal section of the inner wall of the flow channel is a combination of a straight line and a spline curve from top to bottom. The upper 1 / 4 section is a straight line with an angle of 10° to 20° to the vertical direction, preferably 15°. The upper 1 / 4 to the bottom is a spline curve, and the center of curvature is all outside the flow area.

[0052] When the wear-resistant block 4 is embedded in the third air flow channel 103, the outer guard plate 403 is connected to the outer lower guard plate 106 to form the outer wall of the flow channel. The edge line of the longitudinal section of the outer wall of the flow channel is a combination of a straight line and a spline curve from top to bottom. The upper 1 / 5 section is a straight line with an angle of 10° to 20° to the vertical direction, preferably 15°, and the upper 1 / 5 to the bottom is a spline curve, and the center of curvature is all outside the flow area.

[0053] When the wear-resistant block 4 is embedded in the third airflow channel 103, the second blade 401 is docked with the first blade 104 to form a guide blade, and the edge line of the guide blade in contact with the outer wall of the flow channel is a combination of a straight line and a spline curve from top to bottom, and the upper 1 / 4 section is a straight line at 40° to 50° to the horizontal direction, preferably 45°, and the upper 1 / 4 to the bottom is a spline curve, and the angle between the bottom tangent direction and the vertical direction is 0° to 15°. The above setting conforms to the fluid dynamics design, effectively alleviates fluid turbulence, and reduces fluid pressure loss.

[0054] In the present invention:

[0055] The nozzle ring 1 is an open flow channel. The flow area of ​​the first air flow channel of the nozzle ring is relatively large. The local resistance of the air flow here is relatively small. The cross section of the first nozzle of the nozzle ring is a contraction cross section. The contraction area is adjusted according to the air flow resistance. The specific contraction area is adjusted according to the numerical simulation results. The flow channel flow area is adjusted for the purpose of balancing the local resistance of all nozzle ring flow channels. For example, when the cross sections of all flow channels of the nozzle ring (first nozzle) are the same, when the nozzle ring flow channel is close to the primary air outlet (low resistance area 9), the local resistance from the primary air outlet to the nozzle ring flow channel is relatively small. Therefore, it is necessary to reduce the flow area of ​​the first nozzle to increase the resistance and reduce the flow rate. When the nozzle ring flow channel is far from the primary air outlet (high resistance area 10), the local resistance from the primary air outlet to the nozzle ring outlet is relatively large. Therefore, it is necessary to increase the flow area of ​​the first nozzle to reduce the resistance and increase the flow rate. See Figure 4 The low-medium resistance area 9 and the high-resistance area 10. Therefore, the flow area of ​​the first nozzle is gradually increased from close to the primary air outlet to far away from the primary air outlet, so that the air flow velocity at the second nozzle outlet is uniform. Each second nozzle flow channel divided by the second blade in the wear-resistant block is a gas flow channel with equal cross-section, and the gas flow velocity passing through the second nozzle does not change.

[0056] The high-uniformity and low-energy static nozzle ring device of the present invention adopts a static open design. During use, it is fixed in the casing of the coal mill. The nozzle ring does not rotate with the grinding disc support ring, which effectively reduces power consumption during operation and saves operating costs. The primary air flow is blown out from bottom to top through the first air flow channel, the second air flow channel and the third air flow channel in sequence. Among them, the second air flow channel is divided into several first nozzles by the first blade. Due to the asymmetry of the primary air duct, the flow area of ​​each first nozzle on the circumference of the nozzle ring is adjusted through software simulation during actual operation. Specifically, the flow area of ​​the first nozzle gradually increases from close to the primary air outlet to far away from the primary air outlet. After adjustment, the flow field velocity in the nozzle ring area is more uniform, so that the nozzle ring has the characteristics of high uniformity. At the same time, the wear-resistant block is designed to be replaceable, which reduces the maintenance cost and manufacturing cost.

[0057] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high uniformity and low energy consumption static nozzle ring device, characterized in that: include: A nozzle ring, the nozzle ring is fixed inside the housing, the nozzle ring is coaxially arranged with the grinding disc support ring inside the housing, and is located on the outside of the grinding disc support ring, the flow area of ​​the nozzle ring has a first airflow channel, a second airflow channel and a third airflow channel which are sequentially connected from bottom to top, a plurality of first blades are arranged in the second airflow channel, and the plurality of first blades are spaced apart along the circumferential direction of the nozzle ring to separate the second airflow channel into a plurality of first nozzles, and the flow area of ​​the first nozzle gradually increases from close to the primary air outlet to far away from the primary air outlet; A wear-resistant block, wherein the wear-resistant block is detachably embedded in the third air flow channel of the nozzle ring, the wear-resistant block is located on the outer side of the grinding disc support ring, the flow area of ​​the wear-resistant block is separated into second nozzles corresponding to the first nozzles by the second blade, each group of mutually corresponding first nozzles and second nozzles are interconnected, the flow areas of the second nozzles are equal, and the primary air flow is ejected after passing through the first air flow channel, the first nozzle and the second nozzle in sequence; The pressure blocking member includes a first pressure ring and a second pressure ring; the first pressure ring is detachably mounted on the nozzle ring and abuts against the outer wall of the wear-resistant block to limit the wear-resistant block within the third air flow channel of the nozzle ring, and the second pressure ring is detachably mounted on the grinding disc support ring and is in dynamic friction contact with the inner wall of the wear-resistant block.

2. The high uniformity and low energy consumption static nozzle ring device according to claim 1, characterized in that: The opening sizes of each of the first nozzles along the circumferential direction of the nozzle ring are the same, and the opening sizes of each of the first nozzles along the radial direction of the nozzle ring gradually increase from close to the primary air outlet to far away from the primary air outlet.

3. The high uniformity and low energy consumption static nozzle ring device according to claim 1, characterized in that: The maximum flow area of ​​the plurality of first nozzles is 1.5 to 2.5 times the minimum flow area.

4. The high uniformity and low energy consumption static nozzle ring device according to claim 1, characterized in that: The nozzle ring includes an outer upper guard plate, an outer lower guard plate and an inner lower guard plate; the outer upper guard plate is located at the upper end of the outer lower guard plate, the inner lower guard plate is located on the inner side of the outer lower guard plate and is arranged at an interval, so that a first airflow channel and a second airflow channel distributed from bottom to top are formed between the outer lower guard plate and the inner lower guard plate, the inner area of ​​the first end of the outer upper guard plate is a third airflow channel, the second end of the outer upper guard plate is fixedly connected to the inner wall of the casing, and the bottom end of the outer lower guard plate is fixedly connected to the casing.

5. The high uniformity and low energy consumption static nozzle ring device according to claim 4, characterized in that: The outer upper guard plate includes an oblique guard plate and an annular expansion plate; the first end of the annular expansion plate is connected to the oblique guard plate, the second end of the annular expansion plate is fixedly connected to the inner wall of the casing, the oblique guard plate is connected to the outer lower guard plate, the inner side of the oblique guard plate is a third air flow channel, and the oblique guard plate has an angle of 10° to 20° with the vertical direction.

6. The high uniformity and low energy consumption static nozzle ring device according to claim 5, characterized in that: The wear-resistant block includes an inner guard plate and an outer guard plate; the inner guard plate is located on the inner side of the outer guard plate and is spaced to form a flow area of ​​the wear-resistant block, the second blade is located between the inner guard plate and the outer guard plate, the inner guard plate is in dynamic friction contact with the second pressure ring, and the outer guard plate is in contact with the first pressure ring. When the wear-resistant block is embedded in the third air flow channel, the inner guard plate is docked with the inner lower guard plate to form an inner wall of the flow channel, the second blade is docked with the first blade to form a guide blade, and the outer guard plate is docked with the outer lower guard plate to form an outer wall of the flow channel.

7. The high uniformity and low energy consumption static nozzle ring device according to claim 6, characterized in that: When the wear-resistant block is embedded in the third air flow channel, the edge line of the longitudinal section of the inner wall of the flow channel is a combination of a straight line and a spline curve from top to bottom. The upper 1 / 4 section is a straight line at an angle of 10° to 20° to the vertical direction, and the upper 1 / 4 to the bottom is a spline curve, and the center of curvature is all outside the flow area.

8. The high uniformity and low energy consumption static nozzle ring device according to claim 6, characterized in that: When the wear-resistant block is embedded in the third air flow channel, the edge line of the longitudinal section of the outer wall of the flow channel is a combination of a straight line and a spline curve from top to bottom. The upper 1 / 5 section is a straight line at an angle of 10° to 20° to the vertical direction, and the upper 1 / 5 to the bottom is a spline curve, and the center of curvature is all outside the flow area.

9. The high uniformity and low energy consumption static nozzle ring device according to claim 1, characterized in that: When the wear-resistant block is embedded in the third air flow channel, the edge line where the guide blade contacts the outer wall of the flow channel is a combination of a straight line and a spline curve from top to bottom. The upper 1 / 4 section is a straight line at an angle of 40° to 50° to the horizontal direction, and the upper 1 / 4 to the bottom is a spline curve, and the angle between the bottom tangent direction and the vertical direction is 0° to 15°.

10. The high uniformity and low energy consumption static nozzle ring device according to claim 6, characterized in that: The inner guard plate and the outer guard plate both have an angle of 10° to 20° with the vertical direction.

Images