Central drying device and drying method of medium-speed coal mill
By employing a central drying device that combines pre-drying ducts with main drying ducts in a medium-speed coal mill, and utilizing staggered baffles and rotating fixed columns, the problem of uneven drying was solved, achieving uniform drying and efficient preheating of materials, and improving the operational stability and thermal energy utilization rate of the coal mill.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-27
AI Technical Summary
The existing medium-speed coal mills have uneven drying modes, which are particularly difficult to dry wet, lumpy raw coal that has not been crushed, resulting in low grinding efficiency, increased power consumption, and operational accidents.
A central drying device combining pre-drying ducts and main drying ducts is used. Through the design of staggered baffles and rotating fixed columns, a three-dimensional hot air field is formed. Combined with scrapers and sliding connection structure, it can achieve multi-directional drying and anti-sticking of materials.
It significantly improves drying efficiency and thermal energy utilization, ensures uniform drying of materials, reduces power consumption and equipment blockage risk, and guarantees the safe and stable operation of the coal mill.
Smart Images
Figure CN121739716A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medium-speed coal mill technology, specifically to a central drying device and drying method for a medium-speed coal mill. Background Technology
[0002] In coal-fired power generation and coal chemical industries, medium-speed coal mills are the core equipment of pulverizing systems. Their task is to grind raw coal into qualified coal powder, providing fuel for subsequent combustion or gasification processes. Raw coal typically contains high levels of moisture (surface and internal moisture). If it enters the coal mill directly, the damp coal particles will adhere to the grinding discs and rollers, leading to a sharp decrease in grinding efficiency, reduced output, and increased power consumption. In severe cases, it can even cause operational accidents such as coal blockage and vibration. Therefore, thoroughly drying the raw coal entering the coal mill is a prerequisite for ensuring the safe, stable, and economical operation of the pulverizing system.
[0003] Currently, the industry commonly uses a "direct-blowing" hot air drying system as a solution. Hot air from a hot blast stove, waste heat from flue gas, or the boiler tail end is directly delivered into the grinding chamber of the coal mill through a single main drying air duct. Inside the chamber, the hot air carries the already ground coal powder while simultaneously attempting to dry the newly fed raw coal being crushed. However, this single-stage, single-air-source drying mode has significant drawbacks. Because the hot air and material are simultaneously mixed, dried, and transported within the grinding chamber, the high-temperature hot air tends to preferentially contact and quickly carry away the already finely ground, free-flowing coal powder. However, for the damp, clump-like raw coal that has just fallen into the center of the millstone and has not yet been crushed, the hot air struggles to effectively penetrate its dense structure, resulting in uneven drying. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a central drying device and drying method for a medium-speed coal mill, which solves the problem of uneven drying caused by a single-stage, single-air-source drying mode.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a central drying device for a medium-speed coal mill, comprising a base frame, a grinding mill chamber fixedly mounted on the upper surface of the base frame, a main drying air duct fixedly connected and communicating with the outer wall of the grinding mill chamber, a feeding chamber fixedly connected and communicating with the upper surface of the grinding mill chamber, a pre-drying air duct fixedly connected and communicating with the outer wall of the feeding chamber, a filter screen provided inside the port of the pre-drying air duct near the feeding chamber, a fixing rod fixedly connected inside the feeding chamber, an installation cylinder fixedly connected to the outer wall of the fixing rod, a fixing column provided inside the installation cylinder, a cone head fixedly connected to the top of the fixing column, at least two sets of baffles fixedly connected to the outer wall of the fixing column, the upper and lower baffles being staggered, an air conveying assembly provided on the outer wall of the pre-drying air duct, and a feeding port fixedly connected to the upper surface of the feeding chamber.
[0006] Preferably, the air supply assembly includes an air supply pipe, which is fixedly connected to the outer wall of the pre-drying air duct and communicates with the pre-drying air duct. A manifold is fixedly connected to the outer wall of the air supply pipe, and the manifold is fixedly installed on the upper surface of the grinding machine cavity. The air supply pipe communicates with the manifold.
[0007] Preferably, the fixing rod and the fixing column are hollow rods, one end of the fixing rod is fixedly connected to the manifold pipe, the other end of the fixing rod is connected to the mounting cylinder, and the outer wall of the fixing column is fixedly connected to the nozzle.
[0008] Preferably, the bottom end of the fixing column is fixedly connected to the inside of the mounting cylinder.
[0009] Preferably, the bottom end of the fixed column is rotatably connected to the mounting cylinder, and the baffle is positioned close to the air outlet of the pre-drying air duct.
[0010] Preferably, at least one of the baffles has a scraper fixedly connected to its outer wall, and the outer wall of the scraper is slidably connected to the inner wall of the feeding chamber and the outer wall of the filter screen.
[0011] Preferably, the bottom end of the fixing column is slidably connected to the inside of the mounting cylinder, a slider is fixedly connected to the lower surface of the fixing column, a spring is fixedly connected to the lower surface of the slider, and the bottom end of the spring is fixedly connected to the inner bottom wall of the mounting cylinder.
[0012] Preferably, a sliding plate is fixedly connected to the outer wall of the baffle, and the outer wall of the sliding plate is slidably connected to the inner wall of the feeding chamber. The sliding plate slides close to the air outlet of the pre-drying air duct.
[0013] Preferably, a fixing block is fixedly connected to the inner wall of the feeding chamber, and the lower surface of the fixing block can fit against the upper surface of the slide plate.
[0014] A method for central drying of a medium-speed coal mill includes the following steps: S1: Connect the main drying air duct and the manifold to the hot air source; S2: The material to be dried is fed into the feeding chamber through the feeding port; S3: The hot air provided by the hot air source is divided into two paths through the confluence pipe: the first path of hot air is blown into the feeding chamber from the side through the pre-drying air pipe to form a pre-drying air field; the second path of hot air is sprayed from the nozzle to the surrounding area after passing through the fixed rod and fixed column to form a central drying air field. S4: During the falling process, the material is first pre-dried by the combined action of the pre-drying air field and the central drying air field, and is dispersed by the staggered baffles; then the material enters the grinding chamber and is finally dried by the hot air input through the main drying air duct.
[0015] This invention provides a central drying device and drying method for a medium-speed coal mill. It has the following beneficial effects: 1. This invention, by setting up pre-drying air ducts and main drying air ducts, ensures that the material first comes into full contact with the pre-drying hot air in the feeding chamber, completing preliminary dehydration and preheating. This allows for the step-by-step utilization of heat energy, significantly improving the overall drying efficiency and heat energy utilization rate of the system. The device features a fixed column structure with staggered baffles at the pre-drying position in the feeding chamber. When the material falls, it impacts the baffles and is forcibly dispersed, breaking the tendency of damp materials to clump together and changing the material particle group from a dense state to a loose state. This increases the specific surface area of the material, ensuring that the hot air can coat the surface of each particle.
[0016] 2. This invention utilizes a hollow design for the fixing rod and column, connected to a confluence pipe. A nozzle on the outer wall of the fixing column enables central airflow, forming a three-dimensional hot air field with the lateral hot air from the pre-drying duct on the side wall. The hot air diffuses from the center outwards, allowing the material to come into contact with the hot air from multiple directions during its descent. This solves the problem of insufficient drying in the central area of the material caused by traditional lateral airflow, significantly improving the adequacy and uniformity of pre-drying and reducing the heat load of the subsequent final drying.
[0017] 3. This invention converts the kinetic energy of the airflow in the pre-drying duct into mechanical energy, driving the fixed column and baffle to rotate. The rotating baffle generates continuous dynamic collision and scattering effects on the material, achieving a dispersing effect far superior to that of a static baffle. Simultaneously, the rotating components drive the airflow within the cavity to form turbulence, enhancing the heat and mass exchange between the gas and solid phases; furthermore, by installing scrapers on the rotating baffle, they continuously scrape the inner wall of the feeding cavity and the surface of the filter screen during rotation.
[0018] 4. This invention utilizes a buffer mechanism composed of a sliding connection and a spring, enabling the baffle system to adaptively respond to the instantaneous material flow rate. When the material impact is large, the baffle moves downward, both buffering the impact force and protecting the structure, and adjusting the opening of the air vent through the associated mechanism. When the material volume is large and more hot air is required, the slide plate moves downward, widening the air vent; when the material volume is small, the slide plate moves upward, narrowing the air vent. This overcomes the shortcomings of fixed air vents, which either have insufficient or excessive airflow under varying operating conditions.
[0019] 5. In this invention, a fixed block on the inner wall of the feeding chamber and a sliding plate form an impact engagement. When the spring returns and drives the sliding plate upward, the upper surface of the sliding plate impacts the fixed block, generating vibration. This vibration is transmitted through the pipe wall to the entire feeding chamber. This vibration causes material particles adhering to the inner wall to fall off, further preventing long-term material blockage and ensuring smooth material descent. Simultaneously, the vibration helps to shake off adhering material from the baffle and sliding plate surfaces, creating a synergistic anti-blocking effect with the sliding plate's movement, significantly improving the device's anti-blocking capability. Attached Figure Description
[0020] Figure 1This is a perspective view of the present invention; Figure 2 This is a cross-sectional view of the internal structure of the feeding chamber of the present invention; Figure 3 This is a partial structural diagram of the fixing column of the present invention; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a partial structural diagram of the scraper of the present invention; Figure 6 This is a partial structural diagram of the baffle of the present invention; Figure 7 for Figure 6 Enlarged view of point B in the middle; Figure 8 This is a partial structural diagram of the nozzle of the present invention; Figure 9 This is a schematic diagram of a partial structure of the skateboard of the present invention.
[0021] The components are as follows: 1. Base frame; 2. Grinding machine chamber; 3. Main drying air duct; 4. Feeding chamber; 5. Pre-drying air duct; 6. Fixing rod; 7. Mounting cylinder; 8. Fixing column; 9. Baffle; 10. Cone head; 11. Air supply pipe; 12. Combination pipe; 13. Nozzle; 14. Scraper; 15. Slider; 16. Spring; 17. Slide plate; 18. Fixing block; 19. Feeding port. Detailed Implementation
[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] Please see the appendix Figure 1 -Appendix Figure 9 This invention provides a central drying device and drying method for a medium-speed coal mill, including a base frame 1. A grinding mill chamber 2 is fixedly installed on the upper surface of the base frame 1. A main drying air duct 3 is fixedly connected and communicated to the outer wall of the grinding mill chamber 2. A feeding chamber 4 is fixedly connected and communicated to the upper surface of the grinding mill chamber 2. A pre-drying air duct 5 is fixedly connected and communicated to the outer wall of the feeding chamber 4. A filter screen is provided inside the port of the pre-drying air duct 5 near the feeding chamber 4. A fixing rod 6 is fixedly connected inside the feeding chamber 4. An installation cylinder 7 is fixedly connected to the outer wall of the fixing rod 6. A fixing column 8 is provided inside the installation cylinder 7. A cone head 10 is fixedly connected to the top of the fixing column 8. At least two sets of baffles 9 are fixedly connected to the outer wall of the fixing column 8. The upper and lower baffles 9 are staggered. An air conveying assembly is provided on the outer wall of the pre-drying air duct 5.
[0024] Specifically, the base frame 1 of the device is horizontally arranged. A grinding chamber 2 is fixedly mounted on the upper surface of the base frame 1 using bolts. The grinding chamber 2 is a cylindrical structure with an open top. A main drying air duct 3 is welded and connected to one side of its outer wall. The main drying air duct 3 is used to supply hot air into the grinding chamber 2 to complete the final drying of the material. A feeding chamber 4 is coaxially fixedly connected to the upper surface of the grinding chamber 2. The feeding chamber 4 is a cylindrical structure that runs vertically through the material. Its top is a feeding port 19. A pre-drying air duct 5 is welded and connected to the corresponding position on its outer wall. The air inlet direction of the pre-drying air duct 5 faces the inside of the feeding chamber 4. A metal filter screen is embedded and fixed inside the port near the discharge chamber 4; a fixing rod 6 is welded and fixed vertically at the center of the discharge chamber 4; an installation cylinder 7 is fitted and welded to the outer wall of the top of the fixing rod 6; a fixing column 8 is coaxially arranged inside the installation cylinder 7; a cone head 10 is welded and fixed to the top of the fixing column 8; the cone head 10 is conical and is used to guide the falling material to disperse in all directions; at least two sets of baffles 9 are welded and fixed radially to the outer wall of the fixing column 8; the baffles 9 are arc-shaped plate structures; the upper and lower adjacent baffles 9 are arranged in an alternating manner; and an air conveying component is also provided on the outer wall of the pre-drying air duct 5. In practical applications, the material falls into the feeding port 19 at the top of the feeding chamber 4. The air conveying component delivers hot air to the pre-drying air duct 5. The hot air is blown into the feeding chamber 4 through the pre-drying air duct 5 to perform preliminary drying treatment on the falling material. The filter screen can effectively block material particles from entering the pre-drying air duct 5, avoiding pipe blockage. When the material hits the baffle 9 during its fall, the originally damp and sticky material will be further dispersed, increasing the contact area with the hot air and ensuring uniform drying. The baffles 9, which are arranged in an alternating pattern, can not only prevent the material from accumulating in a local area, but also allow the material to hit the baffles 9 multiple times. At the same time, the blocking effect of the baffles 9 can appropriately slow down the falling speed of the material, prolong the residence time of the material in the pre-drying area, ensure sufficient preheating, and lay the foundation for the final drying in the subsequent grinding chamber 2.
[0025] The air supply assembly includes an air supply pipe 11, which is fixedly connected to the outer wall of the pre-drying air duct 5 and communicates with the pre-drying air duct 5. A manifold pipe 12 is fixedly connected to the outer wall of the air supply pipe 11, and the manifold pipe 12 is fixedly installed on the upper surface of the grinding machine cavity 2. The air supply pipe 11 communicates with the manifold pipe 12.
[0026] Specifically, the gas conveying assembly includes a gas conveying pipe 11 and a manifold pipe 12. One end of the gas conveying pipe 11 is welded and fixed to the outer wall of the pre-drying air duct 5 and connected to the inside of the pre-drying air duct 5. The number of gas conveying pipes 11 matches the number of pre-drying air ducts 5, with at least one pipe installed. The other end of the gas conveying pipe 11 is welded and fixed to the manifold pipe 12. The manifold pipe 12 has a ring structure and is horizontally fixed on the upper surface of the grinding mill chamber 2. The inside of the gas conveying pipe 11 is connected to the inside of the manifold pipe 12. The air inlet end of the manifold pipe 12 is used to connect to external hot air supply equipment, such as a hot air furnace or a coal mill waste heat recovery device. Hot air is first centrally distributed through the manifold pipe 12, and then transported to the inside of each gas conveying pipe 11. The gas conveying pipe 11 further transports the hot air into the pre-drying air duct 5, and finally blows it into the feeding chamber 4 to complete the pre-drying of the material. This ensures a stable hot air input to each pre-drying air duct 5 and avoids uneven drying caused by insufficient local hot air supply.
[0027] The fixing rod 6 and the fixing column 8 are hollow rods. One end of the fixing rod 6 is fixedly connected to the confluence pipe 12, and the other end of the fixing rod 6 is connected to the mounting cylinder 7. The nozzle 13 is fixedly connected to the outer wall of the fixing column 8.
[0028] Specifically, both the fixing rod 6 and the fixing column 8 adopt a hollow tubular structure. The fixing rod 6 passes through the top wall of the grinding machine cavity 2 and is welded to the manifold 12. The interior of the fixing rod 6 is connected to the interior of the manifold 12. The fixing rod 6 and the side wall of the mounting cylinder 7 are connected to each other. Multiple nozzles 13 are evenly distributed circumferentially on the pipe wall of the fixing column 8. The spray direction of the nozzles 13 is radial or obliquely downward, and the nozzles 13 are connected to the interior of the fixing column 8. Hot air enters the fixed rod 6 through the confluence pipe 12, then enters the fixed column 8 through the connecting port of the mounting cylinder 7, and finally sprays outwards from the nozzle 13 on the outer wall of the fixed column 8. This design allows the hot air to diffuse from the central area of the feeding chamber 4 to the surrounding areas. Combined with the hot air blown in from the side wall of the feeding chamber 4 by the pre-drying air duct 5, a three-dimensional hot air field combining the center and the sides is formed, allowing the material to come into contact with hot air from multiple directions during the falling process. This avoids the problem of insufficient drying in the central area of the material and further improves the uniformity and sufficiency of pre-drying.
[0029] The bottom end of the fixed column 8 is fixedly connected to the inside of the mounting cylinder 7.
[0030] Specifically, in one embodiment, the fixing column 8 is fixedly installed, with its bottom end directly fixed to the inside of the mounting cylinder 7. This can be achieved by welding to fix the bottom end of the fixing column 8 to the center of the inner bottom wall of the mounting cylinder 7, or by bolting the flange at the bottom of the fixing column 8 to the inner bottom wall of the mounting cylinder 7. This connection method forms an integrated structure between the fixing column 8 and the mounting cylinder 7, resulting in strong overall structural stability. It can withstand the load caused by long-term material impact and is less prone to shifting or loosening. It is suitable for applications with low material hardness and low impact force, ensuring a stable jet direction from the central nozzle 13, guaranteeing a continuous and uniform hot air supply to the central area of the feeding chamber 4, preventing jet range shifts due to the shaking of the fixing column 8, and maintaining a stable pre-drying effect.
[0031] The bottom end of the fixed column 8 is rotatably connected to the mounting cylinder 7, and the position of the baffle 9 is close to the air outlet of the pre-drying air duct 5.
[0032] Specifically, in another embodiment, the bottom end of the fixed column 8 is rotatably connected to the mounting cylinder 7. Specifically, a bearing seat can be installed on the inner bottom wall of the mounting cylinder 7, with the bottom end of the fixed column 8 embedded inside the bearing seat and rotatably engaging with it. The baffle 9 is installed close to the air outlet of the pre-drying duct 5, and the surface of the baffle 9 forms a 30-60 degree angle with the air outlet direction of the pre-drying duct 5. The hot air blown out of the pre-drying duct 5 can directly act on the surface of the baffle 9, using wind power to drive the fixed column 8 to rotate around its own axis, thereby causing all the baffles 9 to rotate synchronously. The rotation of the baffles 9 is achieved using the pre-drying hot air, reducing equipment energy consumption. The rotating baffle 9 can dynamically disperse falling materials; compared to a stationary baffle 9, the material has more contact with the baffle 9, resulting in higher dispersion efficiency. Simultaneously, the rotating baffle 9 will cause surrounding airflow disturbance, further improving the mixing degree of hot air and material, and enhancing the pre-drying effect.
[0033] At least one baffle 9 has a scraper 14 fixedly connected to its outer wall, and the outer wall of the scraper 14 is slidably connected to the inner wall of the feeding chamber 4 and the outer wall of the filter screen.
[0034] Specifically, a scraper 14 is welded and fixed to the outer wall of at least one baffle 9 along the height direction. One edge of the scraper 14 is attached to the inner wall of the feeding chamber 4 and slidably connected to the inner wall of the feeding chamber 4, and is attached to the outer wall of the filter screen at the port of the pre-drying air duct 5 and slidably connected to the filter screen. The scraper 14 structure is added to the rotating baffle 9. When the fixed column 8 drives the baffle 9 to rotate, the scraper 14 rotates synchronously with the baffle 9. The rotating scraper 14 can continuously scrape off the material adhering to the inner wall of the feeding chamber 4, avoiding the long-term adhesion and accumulation of material which reduces the effective volume of the feeding chamber 4. At the same time, the scraper 14 can clean the surface of the filter screen, scrape off the material particles attached to the pores of the filter screen, prevent the filter screen from clogging, ensure the smooth ventilation of the pre-drying air duct 5, reduce the problem of insufficient hot air supply caused by filter screen clogging, and reduce the frequency of manual maintenance of the equipment.
[0035] The bottom end of the fixed column 8 is slidably connected to the inside of the mounting cylinder 7. A slider 15 is fixedly connected to the lower surface of the fixed column 8. A spring 16 is fixedly connected to the lower surface of the slider 15. The bottom end of the spring 16 is fixedly connected to the inner bottom wall of the mounting cylinder 7.
[0036] Specifically, one embodiment is also provided, wherein the bottom end of the fixed column 8 is slidably connected to the mounting cylinder 7. A groove is formed on the inner wall of the mounting cylinder 7 in the vertical direction. A slider 15 is welded and fixed to the outer wall of the bottom end of the fixed column 8, and the slider 15 is embedded in the groove and slides within it. A slider 15 is welded and fixed to the lower surface of the fixed column 8, and a spring 16 is welded and fixed to the lower surface of the bottom slider 15. The bottom end of the spring 16 is welded and fixed to the inner bottom wall of the mounting cylinder 7. The spring 16 is a compression spring, and its elastic coefficient is selected based on the average impact force of the material. The fixed column 8 can slide up and down slightly in the vertical direction of the mounting cylinder 7. When the material falls and hits the baffle 9, the impact force will cause the fixed column 8 to slide downwards and compress the spring 16. The elastic restoring force of the spring 16 will push the fixed column 8 upwards to reset, thereby causing the fixed column 8 to drive the baffle 9 to oscillate up and down slightly. This oscillation effect can effectively prevent material from clogging on the surface of the baffle 9 or in a localized area of the feeding chamber 4, and can also shake off material adhering to the outer wall of the fixed column 8 and the baffle 9.
[0037] A slide plate 17 is fixedly connected to the outer wall of the baffle 9. The outer wall of the slide plate 17 is slidably connected to the inner wall of the feeding chamber 4. The slide plate 17 slides close to the air outlet of the pre-drying air duct 5.
[0038] Specifically, a sliding plate 17 is welded and fixed on the side of the outer wall of the baffle 9 away from the fixed column 8. The sliding plate 17 is a ring-shaped plate structure. Its outer wall is closely attached to the inner wall of the feeding chamber 4 and slides vertically along the inner wall of the feeding chamber 4. The sliding path of the sliding plate 17 covers the air outlet area of the pre-drying air duct 5, that is, the sliding plate 17 can slide between the top and bottom of the air outlet. A sliding plate 17 is added to the baffle 9 that can swing up and down. When the fixed column 8 drives the baffle 9 to swing up and down, the sliding plate 17 moves up and down synchronously along the inner wall of the feeding chamber 4 with the baffle 9. When a large amount of material is fed, the impact is greater. When the baffle 9 drives the sliding plate 17 to descend, the exposed area of the air outlet of the pre-drying air duct 5 increases, and the hot air supply is increased accordingly, which can match the pre-drying needs of a large amount of material. When the material impact decreases and the spring 16 drives the sliding plate 17 to rise, the sliding plate 17 will block part of the air outlet, reduce the hot air supply, and avoid hot air waste. This design realizes the automatic adjustment of the size of the air outlet of the pre-drying air duct 5, so that the hot air supply matches the material quantity, improves the hot air utilization efficiency, and ensures the stability of the pre-drying effect under different material quantities.
[0039] A fixing block 18 is fixedly connected to the inner wall of the feeding chamber 4, and the lower surface of the fixing block 18 can fit against the upper surface of the slide plate 17.
[0040] Specifically, multiple fixing blocks 18 are uniformly welded and fixed along the circumference of the inner wall of the feeding chamber 4. The fixing blocks 18 are block-shaped structures, and their installation positions are located above the lifting path of the slide plate 17. The upper surface of the slide plate 17 can fit against the lower surface of the fixing blocks 18. The number of fixing blocks 18 is selected according to the inner diameter of the feeding chamber 4. In this embodiment, the spring 16 is pre-compressed. The fixing block 18 structure is added on the lifting path of the slide plate 17 to ensure that when the spring 16 resets and drives the slide plate 17 to reset upward with the fixing column 8, the upper surface of the slide plate 17 will hit the lower surface of the fixing block 18. The vibration generated by the impact will be transmitted to the tube wall of the feeding chamber 4 through the fixing block 18. This vibration effect can cause the material particles adhering to the inner wall of the feeding chamber 4 to fall off due to vibration, further preventing the material from sticking to the inner wall of the discharge chamber for a long time, ensuring the smoothness of the material falling. At the same time, the vibration can also help shake off the material adhering to the surface of the baffle 9 and the slide plate 17, forming a synergistic effect with the up and down shaking effect of the slide plate 17, improving the anti-sticking and clogging ability of the device.
[0041] A method for central drying of a medium-speed coal mill includes the following steps: S1: Connect the main drying air duct 3 and the manifold duct 12 to the hot air source; S2: The material to be dried is fed into the feeding chamber 4 through the feeding port 19; S3: The hot air supplied by the hot air source is divided into two paths through the confluence pipe 12: the first path of hot air is blown into the feeding chamber 4 from the side through the pre-drying air pipe 5 to form a pre-drying air field; the second path of hot air is sprayed from the nozzle 13 to the surrounding area after passing through the fixed rod 6 and the fixed column 8 to form a central drying air field. S4: During the falling process, the material is first pre-dried by the combined action of the pre-drying air field and the central drying air field, and is dispersed by the staggered baffles 9; then the material enters the grinding chamber 2 and is finally dried by the hot air input through the main drying air duct 3.
[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A central drying device for a medium-speed coal mill, comprising a base frame (1), characterized in that, A grinding chamber (2) is fixedly installed on the upper surface of the base frame (1). The outer wall of the grinding chamber (2) is fixedly connected to and connected to the main drying air duct (3). A feeding chamber (4) is fixedly connected to the upper surface of the grinding chamber (2). A pre-drying air duct (5) is fixedly connected to and connected to the outer wall of the feeding chamber (4). A filter screen is provided inside the port of the pre-drying air duct (5) near the feeding chamber (4). A fixing rod (6) is fixedly connected inside the feeding chamber (4). An installation cylinder (7) is fixedly connected to the outer wall of the fixing rod (6). A fixing column (8) is provided inside the installation cylinder (7). A cone head (10) is fixedly connected to the top of the fixing column (8). At least two sets of baffles (9) are fixedly connected to the outer wall of the fixing column (8). The upper and lower baffles (9) are staggered. An air conveying component is provided on the outer wall of the pre-drying air duct (5). A feeding port (19) is fixedly connected to the upper surface of the feeding chamber (4).
2. The central drying device for a medium-speed coal mill according to claim 1, characterized in that, The gas delivery assembly includes a gas delivery pipe (11), which is fixedly connected to the outer wall of the pre-drying air duct (5) and communicates with the pre-drying air duct (5). A manifold pipe (12) is fixedly connected to the outer wall of the gas delivery pipe (11), and the manifold pipe (12) is fixedly installed on the upper surface of the grinding machine cavity (2). The gas delivery pipe (11) communicates with the manifold pipe (12).
3. The central drying device for a medium-speed coal mill according to claim 1, characterized in that, The fixing rod (6) and the fixing column (8) are hollow rods. One end of the fixing rod (6) is fixedly connected to the confluence pipe (12), and the other end of the fixing rod (6) is connected to the mounting cylinder (7). The outer wall of the fixing column (8) is fixedly connected to the nozzle (13).
4. The central drying device for a medium-speed coal mill according to claim 3, characterized in that, The bottom end of the fixed column (8) is fixedly connected to the inside of the mounting cylinder (7).
5. The central drying device for a medium-speed coal mill according to claim 3, characterized in that, The bottom end of the fixed column (8) is rotatably connected to the mounting cylinder (7), and the position of the baffle (9) is close to the air outlet of the pre-drying air duct (5).
6. The central drying device for a medium-speed coal mill according to claim 5, characterized in that, At least one of the baffles (9) has a scraper (14) fixedly connected to its outer wall, and the outer wall of the scraper (14) is slidably connected to the inner wall of the feeding chamber (4) and the outer wall of the filter screen.
7. The central drying device for a medium-speed coal mill according to claim 3, characterized in that, The bottom end of the fixed column (8) is slidably connected to the inside of the mounting cylinder (7). A slider (15) is fixedly connected to the lower surface of the fixed column (8). A spring (16) is fixedly connected to the lower surface of the slider (15). The bottom end of the spring (16) is fixedly connected to the inner bottom wall of the mounting cylinder (7).
8. The central drying device for a medium-speed coal mill according to claim 7, characterized in that, The outer wall of the baffle (9) is fixedly connected to a slide plate (17), the outer wall of the slide plate (17) is slidably connected to the inner wall of the feeding chamber (4), and the slide plate (17) slides close to the air outlet of the pre-drying air duct (5).
9. The central drying device for a medium-speed coal mill according to claim 8, characterized in that, The inner wall of the feeding chamber (4) is fixedly connected to a fixing block (18), and the lower surface of the fixing block (18) can fit against the upper surface of the slide plate (17).
10. A method for central drying of a medium-speed coal mill, characterized in that, A central drying device for a medium-speed coal mill according to any one of claims 1-9, comprising the following steps: S1: Connect the main drying air duct (3) and the manifold (12) to the hot air source; S2: The material to be dried is fed into the feeding chamber (4) through the feeding port (19); S3: The hot air provided by the hot air source is divided into two paths through the confluence pipe (12): the first path of hot air is blown into the feeding chamber (4) from the side through the pre-drying air pipe (5) to form a pre-drying air field; the second path of hot air is sprayed from the nozzle (13) to the surrounding area after passing through the fixed rod (6) and the fixed column (8) to form a central drying air field. S4: During the falling process, the material is first pre-dried by the combined action of the pre-drying air field and the central drying air field, and is dispersed by the staggered baffles (9); then the material enters the grinding chamber (2) and is finally dried by the hot air input through the main drying air duct (3).