A vertical mill material mill internal direct return guide structure

Abstract

This invention relates to the field of vertical mill technology, specifically to a material return guide structure for a vertical mill, comprising a guide support and a guide assembly. The serpentine guide trough is spirally ascending, lifting the material thrown from the edge of the mill disc to a certain height. The guide assembly provides centripetal force to the material and overcomes gravitational potential energy, guiding the thrown large-diameter material back onto the mill disc. The kinetic energy of the large-diameter material thrown from the mill disc is recovered and utilized. The serpentine guide trough converts the kinetic energy into potential energy, lifting the material to a certain height. Then, the material returns to the mill disc under the action of gravity and the guidance of the return trough. The setting of multiple guide assemblies precisely controls the distribution of the material's landing point and the distribution pattern on the mill disc. In conjunction with the rotating mill disc, it ensures that the material remains within the grinding zone H of the mill disc before being thrown out again. The targeted feeding method realizes short-distance circulation of large-diameter material within the mill, improving the grinding efficiency of the vertical mill device.

Description

Technical Field

[0001] This invention relates to the field of vertical mill technology, specifically to a direct return material guiding structure inside a vertical mill. Background Technology

[0002] A vertical mill is an energy-saving grinding equipment. Its working principle is that the grinding structure consists of grinding rollers and a grinding disc. Pressure is applied to the material on the disc to crush it and produce a product with the target particle size. When the vertical mill is working, the material is fed into the mill and falls onto the grinding disc. The grinding disc rotates and throws the material to the edge. When the material reaches the crushing zone, it is crushed by high pressure. The crushed material is thrown out from the edge of the grinding disc and then conveyed out of the vertical mill. It is then lifted by an external circulation elevator to a sorting or screening device. Qualified products are selected out, and unqualified parts (large-diameter materials) are fed back into the vertical mill for further crushing. This cycle continues.

[0003] The exhaust system in a vertical mill creates an upward airflow inside the mill, suspending the fine particles and conveying them to the classifier. However, because vertical milling is unconfined grinding, not all material is pulverized as it passes through the grinding rollers. Even the pulverized material may not all meet the product particle size requirements at once. Therefore, a large portion (at least 50%) of the material ejected from the mill discs consists of large-sized non-product particles. The current common technology for recycling this material back to the mill discs involves using an external elevator. However, when processing large volumes of material, the elevator's motor power requirement increases significantly, leading to higher overall energy consumption. In the external circulation device, substandard materials slide into the bottom discharge port under gravity. The material discharged from the mill is conveyed by a conveyor in the horizontal conveying section and then by an elevator to the top of the mill in the vertical lifting section. Finally, the material is returned to the feeding system. This process includes the material discharge stage, the mechanical conveying stage, and the graded return stage. The material travels a long path throughout the process, which takes a long time and may affect the grinding efficiency. Secondly, the collision between the material and the equipment during the conveying process will accelerate the wear of the shell and generate more noise, which will have an adverse impact on the working environment. At the same time, the stability of the external circulation device is greatly affected by the characteristics of the material. When the material particle size is too large or the moisture content is too high, it is easy to cause blockage in the elevator or conveying pipeline.

[0004] Therefore, the present invention provides a material return guide structure that enables the circulation of large-diameter materials inside a vertical mill. This device does not require additional power and belongs to a vertical mill material circulation technology. Summary of the Invention

[0005] To address the issues of high energy consumption and low grinding efficiency in the material circulation devices of existing vertical mills, this invention provides a direct return material guiding structure inside the vertical mill.

[0006] The technical solution adopted by this invention to solve its technical problem is: a material return guide structure for a vertical mill, including a guide support and a guide assembly; the guide assembly includes a serpentine guide trough and a return trough. The serpentine guide trough is spirally ascending, lifting the material thrown out of the mill disc from the edge of the mill disc to a certain height. The center line of the serpentine guide trough is a cylindrical spiral, and its projection on the horizontal plane is an arc. The diameter of the arc is larger than the diameter of the mill disc. The curved design reduces the requirements on the inner diameter of the vertical mill shell. The bottom of the serpentine guide trough is a bottom plate that is inclined towards the center of the mill disc of the vertical mill device. The inclination angle of the middle section of the bottom plate towards the center of the vertical mill decreases as the height of the serpentine guide trough increases, reducing the lateral acceleration of the material when it makes a decelerating spiral motion upward, and reducing the wear on the serpentine guide trough. The guide assembly is used to provide centripetal force for the material and overcome gravitational potential energy, guiding the large-diameter material that has been thrown out back to the mill disc.

[0007] Preferably, the material guiding components are arranged in multiple sets distributed around the grinding disc of the vertical grinding device, and each material guiding component has the same height. The spiral angle of each serpentine material guiding groove is different. The closer to the next grinding roller, the larger the spiral angle and the shorter the length of the serpentine material guiding groove. The material guiding bracket corresponds to the material guiding component.

[0008] Preferably, the material guiding assembly further includes a connecting plate, which is generally ring-shaped and located below the serpentine material guiding channel. There are transition plates between the connecting plate and the multiple serpentine material guiding channels.

[0009] Preferably, the side of the connecting plate closest to the edge of the grinding disc is rounded and the connecting plate is not connected to the grinding disc.

[0010] Preferably, the return trough includes an upper trough and a lower trough, the upper end of the serpentine guide trough is fixedly connected to the upper trough, the end of the upper trough away from the serpentine guide trough is rotatably connected to the lower trough, and the lower trough is inclined downward toward the grinding disc.

[0011] Preferably, the serpentine feed trough further includes a trough bottom plate and a baffle plate fixedly connected to the side of the trough bottom plate away from the grinding disc.

[0012] Preferably, the connecting plate has alternating openings for material leakage holes and grooves. The material leakage holes are located below the transition plate, and the grooves are located outside the grinding roller. The number of grooves is the same as that of the grinding roller.

[0013] Preferably, the connecting plate has a groove and a serrated connecting port on its edge to connect to a transition plate. The transition plate has a material leakage hole. The groove is located outside the grinding roller and the number of grooves is the same as that of the grinding roller. The serpentine guide trough also includes a bottom plate and a baffle fixedly connected to the bottom side of the bottom plate.

[0014] Preferably, the material guide bracket includes a support component and an adjustment component. One end of the support component and the adjustment component are fixedly connected to the inner wall of the housing, and the other end of the support component is corresponding to the material guide component. The end of the support component away from the inner wall of the housing is fixedly connected to the lower end of the material guide component. The end of the adjustment component away from the inner wall of the housing is movably connected to the return trough. The adjustment component is located at the bottom of the support component.

[0015] Preferably, guide holes are provided on both sides of the bottom plate of the trough.

[0016] The beneficial effects of this invention are:

[0017] (1) The material return guide structure in the vertical mill described in this invention recovers and utilizes the kinetic energy of large-diameter materials when they are thrown from the mill disc. The kinetic energy is converted into potential energy through the serpentine guide trough, which lifts the material to a certain height. Then, the material returns to the mill disc under the action of gravity and the guidance of the return trough. The setting of multiple sets of guide components precisely controls the distribution of the material landing point and the distribution pattern on the mill disc. In conjunction with the rotating mill disc, it ensures that the material can reach the grinding belt of the mill disc before being thrown out of the mill disc again. The targeted feeding method realizes the short-distance circulation of large-diameter materials in the mill and improves the grinding efficiency of the vertical mill device.

[0018] (2) The material direct return guide structure inside the vertical mill described in this invention, with the guide hole setting in conjunction with the rising airflow inside the vertical mill device, can provide auxiliary force for large-diameter materials to a certain extent, and assist the large-diameter materials to move upward along the serpentine guide groove.

[0019] (3) The material return structure inside the vertical mill described in this invention allows large-diameter materials thrown out of the mill to be returned directly inside the device, reducing the amount of material in external circulation, reducing the specifications and power consumption of the external circulation lifting device, and reducing the investment and operating costs of material external circulation in the vertical mill.

[0020] (4) The material return guide structure inside the vertical mill described in this invention reduces the impact and scouring of the mill shell after the material is thrown out by the grinding disc, thereby reducing the wear of the mill shell. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram showing the connection between the material guide bracket and the material guide assembly provided by the present invention;

[0024] Figure 3This is a schematic diagram showing the connection between the material guiding assembly and the grinding disc provided by the present invention;

[0025] Figure 4 This is a schematic diagram showing the connection between the serpentine guide trough and the return trough provided by the present invention;

[0026] Figure 5 This invention provides a schematic diagram of the material movement trajectory.

[0027] Figure 6 This is a top view of the return trough provided by the present invention;

[0028] Figure 7 This is a schematic diagram showing the connection between the adjustment component and the return trough provided by the present invention;

[0029] Figure 8 A schematic diagram showing the trend of the inclination angle of the bottom plate of the groove towards the center of the vertical mill as it rises from low to high, as provided by the present invention.

[0030] Figure 9 A schematic diagram of the straightened bottom plate of the groove provided by the present invention;

[0031] Figure 10 A second schematic diagram showing the straightened state of the bottom plate of the groove provided by the present invention;

[0032] Figure 11 This is a schematic diagram of the connecting plate provided by the present invention;

[0033] Figure 12 A schematic diagram illustrating the connection between the connecting plate and the return trough in another embodiment of the present invention;

[0034] Figure 13 This is a schematic diagram of another form of the serpentine guide channel provided by the present invention.

[0035] In the diagram: 1. Material guide bracket; 11. Support assembly; 12. Adjustment assembly; 2. Material guide assembly; 21. Serpentine material guide trough; 211. Trough bottom plate; 212. Baffle; 22. Return trough; 221. Upper trough; 222. Lower trough; 23. Transition plate; 24. Connecting plate; 25. Material leakage hole; 26. Guide hole; 27. Leakage channel; 3. Material width-to-thickness ratio adjustment assembly. Detailed Implementation

[0036] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0037] Example 1: As Figures 1-11As shown, the present invention discloses a material return guide structure for a vertical mill, comprising a material guide support 1 and a material guide assembly 2. The material guide assembly 2 includes a serpentine material guide trough 21 and a return trough 22. The serpentine material guide trough 21 is spirally ascending, lifting the material thrown from the edge of the mill disc to a certain height. The center line of the serpentine material guide trough 21 is a cylindrical spiral, and its projection on the horizontal plane is an arc. The diameter of the arc is larger than the diameter of the mill disc. The curved design reduces the requirements on the inner diameter of the vertical mill shell. The bottom of the serpentine material guide trough 21 is a bottom plate 211 inclined towards the center of the mill disc. The inclination angle of the middle section of the bottom plate 211 towards the center of the vertical mill decreases as the height of the serpentine material guide trough 21 increases, reducing the lateral acceleration of the material during its upward decelerating spiral motion and reducing wear on the serpentine material guide trough 21. The material guide assembly 2 is used to provide centripetal force for the material and overcome gravitational potential energy, guiding the thrown large-diameter material back onto the mill disc.

[0038] In this embodiment, the material enters the housing of the vertical mill from the top and falls onto the grinding disc. A motor at the bottom of the disc drives its rotation, grinding the material in conjunction with a fixed set of grinding rollers. Fine particles are discharged and collected outside the vertical mill by the exhaust fan above the grinding disc. As the grinding disc rotates, the material on it moves outwards under centrifugal force. Some material slides off the edge of the grinding disc onto the connecting plate 24. Smaller particles leak through the discharge hole 25 on the connecting plate 24 and exit the mill from the discharge port at the bottom. Under the action of the external circulation device, the material is reintroduced into the mill from the top. Larger particles cannot pass through the discharge hole 25 and are further ground by the external circulation fan. The guide plate 23 and the serpentine guide trough 21 move upwards. Each serpentine guide trough 21 is connected to a return trough 22 at its upper end. When it reaches the highest point of the serpentine guide trough 21, it returns to the grinding disc under the action of gravity and the guidance of the return trough 22, realizing the circulation of large-diameter materials inside the vertical mill device and reducing the amount of external circulation. The length of the serpentine guide trough 21 of each guide component 2 is different to adapt to the change in distance between the guide component 2 and the grinding roller. The closer the serpentine guide trough 21 is to the next grinding roller, the shorter its length. Since the height of the serpentine guide trough 21 is constant, it means that its inclination angle is larger, so that the material can return to the grinding disc under the guidance of each set of guide components 2 and can be targeted and fed into the grinding belt H of the grinding disc.

[0039] like Figure 1-Figure 5As shown, the material guiding assembly 2 is provided with multiple sets distributed around the grinding disc of the vertical grinding device, and each material guiding assembly 2 has the same height. The spiral angle of each serpentine material guiding groove 21 is different. The closer to the next grinding roller, the larger the spiral angle and the shorter the length of the serpentine material guiding groove 21. The material guiding bracket 1 corresponds to the material guiding assembly 2. The serpentine material guiding groove 21 also includes a groove bottom plate 211 and a baffle 212 fixedly connected to the side of the groove bottom plate 211 away from the grinding disc. The material guiding assembly 2 also includes a connecting plate 24. The 24 is ring-shaped and located below the serpentine guide trough 21. The connecting plate 24 and the multiple serpentine guide troughs 21 are smoothly transitioned by transition plates 23. The return trough 22 includes an upper trough 221 and a lower trough 222. The upper end of the serpentine guide trough 21 is fixedly connected to the upper trough 221. The end of the upper trough 221 away from the serpentine guide trough 21 is rotatably connected to the lower trough 222. The lower trough 222 is inclined downward towards the grinding disc. The side of the connecting plate 24 near the edge of the grinding disc is smoothly arranged and the connecting plate 24 is not connected to the grinding disc.

[0040] In this embodiment, after the material passes through the sieve and enters the serpentine guide trough 21, the material is diverted as the serpentine guide trough 21 slides. When the vertical mill is working, the fine particles are discharged from the vertical mill by the airflow under the action of the exhaust device inside the mill and collected. The bottom plate 211 of the serpentine guide trough 21 is inclined at an angle to the center of the vertical mill that matches the initial kinetic energy of the grinding disc. When the grinding disc rotates, the guide assembly 2 is not affected by the rotation of the grinding disc. The rotating grinding disc throws the material out. There is a trough 27 at the connecting plate 24 on the outside of the two grinding rollers. The material thrown to this trough is either ground by the grinding rollers or falls directly from the trough 27 to the outside of the mill and enters the external circulation device. The material thrown onto the connecting plate 24 is screened through the discharge hole 25. Material that cannot pass through the discharge hole is screened. Large-diameter materials from hole 25 begin to move upward along the serpentine guide trough 21. The return trough 22, connected to the higher end of the serpentine guide trough 21, bends and tilts towards the grinding disc. The return trough 22 includes an upper trough 221 and a lower trough 222. The upper trough 221 is fixedly connected to the upper end of the serpentine guide trough 21, and the lower trough 222 is movably connected to the end of the upper trough 221 away from the serpentine guide trough 21. The side wall of the lower trough 222 is provided with a sliding groove, allowing for adjustment when the lower trough 222 is pulled by the electric telescopic rod. The height of the lower end of the lower trough 222 can be adjusted slightly by the adjustment component 12. When the height of the lower end of the lower trough 222 is adjusted, its upper end remains connected to the upper trough 221. When the large-diameter materials separate from the guide component 2, they fall onto the grinding disc. Without a return chute 22 facing the grinding disc at the end, large-diameter materials may not return to the grinding disc or fall into the grinding belt H on the grinding disc when separated from the guide assembly 2. The distance between each guide assembly 2 and the next grinding roller is different. The length of the serpentine guide chute 21 of each guide assembly 2 is adapted to the distance between each guide assembly 2 and the next grinding roller. The closer to the next grinding roller, the shorter the length of the serpentine guide chute 21 of the guide assembly 2, to avoid deviation of the material drop point P2 and prevent the material from reaching the grinding belt H of the grinding disc. The bottom plate 211 of the lower end of each serpentine guide chute 21 has the same inclination angle towards the center of the vertical mill, and the inclination angle of the lower end of the serpentine guide chute 21 towards the center of the vertical mill is greater than that of the middle section, and the inclination angle of the middle section towards the center of the vertical mill is greater than that of the upper end. With the same height for each set of guide components 2, the landing point of each guide component 2 on the grinding disc is different, meaning the distance between the landing point of each guide component 2 and the next grinding roller is different. The landing point P2 is set within the grinding belt H area of ​​the grinding disc, allowing the material to directly enter the grinding rollers for grinding as the grinding disc rotates. This improves the grinding efficiency after material return and reduces the occurrence of material failing to enter the grinding belt after return. When the ejected material returns to the grinding disc after passing through the guide component 2, it will also move outward under the centrifugal force generated by the rotating grinding disc. The different landing point settings ensure that the material remains within the grinding belt H of the grinding disc before being ejected again and is then bitten into the grinding rollers for grinding.The paths and distances of materials arriving at the same grinding roller differ depending on their landing point. The multiple sets of guiding components 2 function to guide the ejected material back onto the grinding disc through targeted feeding, ensuring that the returned material remains within the grinding belt H of the grinding disc, thus avoiding ineffective internal circulation and reducing external circulation.

[0041] In this embodiment, as Figure 5 As shown, the highest point of the material is P1, the drop point is P2, and the grinding belt of the grinding disc is H. The material moves on the serpentine guide trough 21. After reaching the highest point P1, it enters the return trough 22. Guided by the return trough 22, the material returns to the grinding disc. The drop point P2 of different guide components 2 is different. All drop points P2 are within the area of ​​the grinding belt H of the grinding disc. The rotation of the grinding disc can drive the material to approach the grinding roller, making it easier for the grinding roller to bite the material.

[0042] like Figure 2-Figure 4 As shown, the connecting plate 24 is alternately provided with a material leakage hole 25 and a leakage groove 27. The material leakage hole 25 is located below the transition plate 23, and the leakage groove 27 is located outside the grinding roller. The number of leakage grooves 27 is the same as that of the grinding roller. The bottom plate 211 of the groove is provided with guide holes 26 on both sides. The material guide bracket 1 includes a support component 11 and an adjustment component 12. One end of the support component 11 and the adjustment component 12 are fixedly connected to the inner wall of the shell, and the other end is corresponding to the material guide component 2. The end of the support component 11 away from the inner wall of the shell is fixedly connected to the lower end of the material guide component 2, and the end of the adjustment component 12 away from the inner wall of the shell is movably connected to the return groove 22.

[0043] In this embodiment, materials with a particle size smaller than the discharge hole 25 are screened and enter the external circulation lifting device. Under the action of the external circulation lifting device, this part of the material is fed back from the top of the vertical mill. Large-diameter materials with a size larger than the discharge hole 25 have greater mass and inertia, making it easier for them to overcome air resistance and move along a stable trajectory. During this process, the exhaust device is always in operation, separating fine particles from coarse particles. At the same time, the guide holes 26 on both sides of the bottom plate 211 can also provide some assistance for the rise of large-diameter materials. The diameter of the guide holes 26 is smaller than the diameter of the discharge hole 25. The bottom plate 211 is close to The guide hole 26 on one side of the grinding disc is inclined towards the middle of the bottom plate 211 to assist the movement of large-diameter materials on the serpentine guide trough 21. The guide bracket 1 provides support for the guide assembly 2, so that the guide assembly 2 can remain stable when the grinding disc rotates and is not affected by the grinding disc. Both the support assembly 11 and the adjustment assembly 12 are provided with arc-shaped plates fixedly connected to the inner wall of the shell. Multiple support plates are fixedly connected to the arc-shaped plate of the support assembly 11, and each support plate corresponds to one guide assembly 2. The end of the support plate away from the arc-shaped plate is fixedly connected to the lower end of the guide assembly 2. Multiple adjustment plates are fixedly connected to the arc-shaped plate of the adjustment assembly 12, and each adjustment plate also corresponds to one guide assembly 2. The material guiding assembly 2 has an adjusting plate whose end away from the arc-shaped plate is fixedly connected to the bottom of the return trough 22. One end of the support assembly 11 is fixedly connected to the housing of the vertical mill, and the other end is fixedly connected to the lower end of the material guiding assembly 2. One end of the bracket of the adjusting assembly 12 is fixedly connected to the housing of the vertical mill, and the other end is fixedly connected to the upper end of the serpentine material guiding trough 21. In one embodiment of the adjusting assembly 12, an electric telescopic rod is connected to the end of the adjusting plate away from the arc-shaped plate. The electric telescopic rod is located at the bottom of the upper trough 221, and its telescopic end is movably connected to the bottom of the lower trough 222. When the electric telescopic rod extends or retracts, it can adjust the tilt angle of the lower trough 222 of the return trough 22. The electric telescopic rod is used to control the small-amplitude rotation of the return trough 22, thereby adjusting the return angle. When the electric telescopic rod is shortened, it pulls the lower trough 222, causing the lower end of the lower trough 222 to be pulled down and closer to the grinding disc. Conversely, when the electric telescopic rod is extended, the lower end of the lower trough 222 moves away from the grinding disc. The upper trough 221 and the lower trough 222 of the return trough 22 have an overlapping part. The bottom plate of the lower trough 222 is located below the bottom plate of the upper trough 221. When the material separates from the upper end of the serpentine guide trough 21, it enters the upper trough 221 of the return trough 22, and then falls onto the grinding disc through the lower trough 222. The return angle of the return trough 22 is adjusted by controlling the electric telescopic rod according to the actual usage.

[0044] In this embodiment, as Figure 6As shown, a material width-to-thickness ratio adjustment component 3 can also be installed in the lower groove 222 of the return material trough 22. This component includes another electric telescopic rod that is fixedly connected to the inner walls on both sides of the lower groove 222 of the return material trough 22. The telescopic end of the other electric telescopic rod is fixedly connected to a sliding plate that can slide on the bottom plate of the lower groove 222. By controlling the other electric telescopic rod, the sliding plate can be moved to adjust the width of the groove opening of the lower groove 222 before the material enters the grinding disc.

[0045] Example 2: Basically similar to Example 1, except that... Figure 12 and Figure 13 As shown, the connecting plate 24 has a groove 27 and a serrated connecting port on its edge to connect to the transition plate 23. The transition plate 23 has a material leakage hole 25. The groove 27 is located outside the grinding roller, and the number of grooves 27 is the same as that of the grinding roller. The serpentine guide trough 21 also includes a bottom plate 211 and a baffle 212 fixedly connected to the bottom side of the bottom plate 211.

[0046] In this embodiment, baffles 212 are provided on both sides of the serpentine guide trough 21, and material leakage holes 25 are opened on the transition plate 23. The transition plate 23 is fixedly connected to the serrated interface of the connecting plate 24. The end of the transition plate 23 away from the connecting plate 24 is fixedly connected to the serpentine guide trough 21, and the side plate of the transition plate 23 smoothly transitions to the baffle 212 on the inner side of the serpentine guide trough 21. When the grinding disc rotates, the connecting plate 24 and each serpentine guide trough 21 do not rotate with the grinding disc. The material guiding assembly 2 is fixed to the inner wall of the housing through the material guiding bracket 1. When the material on the grinding disc is thrown out, it first reaches the connecting plate 24, and then climbs up to the serpentine guide trough 21 through the transition plate 23. During this period, the material is screened on the transition plate 23 by the discharge hole 25. The smaller particle size material enters the external circulation lifting device through the discharge hole 25. The larger particle size material that cannot pass through the discharge hole 25 is guided upward by the combined action of the inner side plate and bottom plate of the transition plate 23 when passing through the transition plate 23. After the larger particle size material reaches the serpentine guide trough 21, since the bottom plate 211 of the serpentine guide trough 21 is in the shape of a cylindrical spiral ascent, the material needs centripetal force to move in a circle. The supporting force that guides the material to climb upward is only provided by the bottom plate 211 of the serpentine guide trough 21. After the material leaves the return trough 22, it returns to the grinding disc and is ground by the grinding roller.

[0047] Working Principle: During operation, material is fed onto the grinding disc from the top of the vertical mill casing. The rotating disc throws some material outwards, while the remaining material is ground and crushed in the grinding zone of the grinding rollers. Fine particles are discharged from the vertical mill by the airflow generated by the exhaust system within the mill system and are collected and screened. The thrown-out material is screened through the discharge hole 25. Smaller particles pass through the discharge hole 25 and enter the external circulation lifting device, while larger particles that cannot pass through the discharge hole 25 are... Guided by the transition plate 23 and the serpentine guide trough 21, the material moves spirally upward. The guide assembly 2 provides centripetal force to the large-diameter material and overcomes gravitational potential energy, guiding the large-diameter material to move within the serpentine guide trough 21. After leaving the return trough 22, the material falls onto the grinding disc. When the material contacts the guide assembly 2, it is subjected to three forces as it slides upward along the cylindrical spiral: gravity, the supporting force of the guide assembly 2 on the material, and the frictional force of the guide assembly 2 on the material. The kinetic energy of the material when it is thrown out from the periphery of the grinding disc is transferred through the guiding action of the guide assembly 2. The increased potential energy from the rising material is converted into energy to overcome friction as the material slides to the highest point of the guide assembly 2. Each guide assembly 2 has a different length of serpentine guide chute 21, which, in conjunction with the return chute 22, results in different material landing positions. This controls the material's landing point distribution and distribution pattern on the grinding disc. A landing point farther from the next grinding roller results in a longer trajectory for the material as it approaches the roller compared to a landing point closer to the next grinding roller. The different landing positions allow the material to return to the rotating grinding disc more efficiently. With the help of centrifugal force, the material can accurately reach the grinding belt H of the grinding disc. All the material drop points P2 are within the grinding belt H. The material discharge holes 25 of the material guide component 2 will screen the materials of different sizes that are thrown out of the grinding disc. The large-diameter material is circulated in the mill by targeted feeding. All the energy required comes from the recovery of the material's kinetic energy. This achieves the internal circulation of some large-diameter materials. Smaller-diameter materials are more susceptible to disturbance and their trajectory is affected. Therefore, they are circulated through the external circulation lifting device, which reduces the energy consumption of the external circulation lifting device and greatly reduces the operating cost.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A material return guiding structure for a vertical mill, characterized in that: Includes a material guide bracket (1) and a material guide assembly (2); The material guiding assembly (2) includes a serpentine material guiding trough (21) and a return trough (22). The serpentine material guiding trough (21) is spirally ascending, lifting the material thrown out by the grinding disc from the edge of the grinding disc to a certain height. The center line of the serpentine material guiding trough (21) is a cylindrical spiral, and its projection on the horizontal plane is an arc. The diameter of the arc is larger than the diameter of the grinding disc. The curved design reduces the requirement for the inner diameter of the vertical mill housing. The bottom of the serpentine material guiding trough (21) is a bottom plate (211) that is inclined towards the center of the grinding disc of the vertical mill device. The inclination angle of the middle section of the bottom plate (211) towards the center of the vertical mill varies with the serpentine material guiding trough. The height of the groove (21) increases and becomes smaller, reducing the acceleration of the material moving laterally when it makes a decelerating spiral motion upward, reducing the wear on the serpentine guide groove (21). The guide component (2) is used to provide centripetal force for the material and overcome the gravitational potential energy, guiding the large-diameter material that has been thrown out back to the grinding disc. The material moves on the serpentine guide groove (21), and after reaching the highest point of the material, it enters the return groove (22). The return groove (22) guides the material back to the grinding disc. The drop points of different guide components (2) are different, and all drop points are within the grinding zone of the grinding disc. The material guiding assembly (2) is provided with multiple sets distributed around the grinding disc of the vertical grinding device, and each material guiding assembly (2) has the same height. The spiral angle of each serpentine material guiding groove (21) is different. The closer it is to the next grinding roller, the larger its spiral angle and the shorter the length of the serpentine material guiding groove (21). The material guiding bracket (1) corresponds to the material guiding assembly (2).

2. The material return guide structure inside a vertical mill according to claim 1, characterized in that: The material guiding assembly (2) also includes a connecting plate (24), which is ring-shaped and located below the serpentine material guiding groove (21). There are transition plates (23) between the connecting plate (24) and the multiple serpentine material guiding grooves (21).

3. The material return guide structure inside a vertical mill according to claim 2, characterized in that: The connecting plate (24) is rounded on the side near the edge of the grinding disc and is not connected to the grinding disc.

4. The material return guide structure inside a vertical mill according to claim 3, characterized in that: The return trough (22) includes an upper trough (221) and a lower trough (222). The upper end of the serpentine guide trough (21) is fixedly connected to the upper trough (221). The end of the upper trough (221) away from the serpentine guide trough (21) is rotatably connected to the lower trough (222). The lower trough (222) is inclined downward toward the grinding disc.

5. The material return guide structure inside a vertical mill according to claim 4, characterized in that: The serpentine feed trough (21) also includes a bottom plate (211) and a baffle (212) fixedly connected to the side of the bottom plate (211) away from the grinding disc.

6. The material return guide structure inside a vertical mill according to claim 5, characterized in that: The connecting plate (24) is alternately provided with a material leakage hole (25) and a leakage groove (27). The material leakage hole (25) is located below the transition plate (23), and the leakage groove (27) is located outside the grinding roller. The number of leakage grooves (27) is the same as that of the grinding roller.

7. The material return guide structure inside a vertical mill according to claim 4, characterized in that: The connecting plate (24) has a groove (27) and a serrated connecting port on its edge to connect to a transition plate (23). The transition plate (23) has a material leakage hole (25). The groove (27) is located outside the grinding roller, and the number of grooves (27) is the same as that of the grinding roller. The serpentine guide trough (21) also includes a bottom plate (211) and a baffle (212) fixedly connected to the bottom side of the bottom plate (211).

8. A material return guide structure for a vertical mill according to claim 6 or 7, characterized in that: The material guide bracket (1) includes a support component (11) and an adjustment component (12). One end of the support component (11) and the adjustment component (12) are fixedly connected to the inner wall of the housing, and the other end of the support component (11) is corresponding to the material guide component (2). The end of the support component (11) away from the inner wall of the housing is fixedly connected to the lower end of the material guide component (2), and the end of the adjustment component (12) away from the inner wall of the housing is movably connected to the return trough (22).

9. The material return guide structure inside a vertical mill according to claim 8, characterized in that: The bottom plate (211) of the trough is provided with flow guide holes (26) on both sides.

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