A vertical roller mill and a manufactured sand production system

Abstract

The application discloses a vertical roller mill and a machine-made sand production system, and relates to grinding equipment technology. The roller mill comprises a grinding part, wherein a grinding disc and a grinding roller constitute part of the grinding part. The roller mill comprises a pre-milling part and an adaptive material blocking adjusting part. The pre-milling part is composed of a feeding center shaft and milling units, and the feeding center shaft is located above the grinding disc. The N milling units are uniformly distributed around the feeding center shaft, and the pre-milling part of the milling units is in contact with the grinding end face of the grinding disc. The adaptive material blocking adjusting part comprises a rocker seal frame, a material blocking device and a linkage assembly. The rocker seal frame serves as a grinding roller support and is installed on the roller mill rack. The material blocking device comprises a fixed material blocking device and a sliding material blocking device combined with the fixed material blocking device through vertical movement, and the two devices jointly form a surrounding blocking structure. The linkage assembly connects the rocker seal frame and the sliding material blocking device, so that the rocker seal frame drives the sliding material blocking device to move upwards through the linkage assembly. Through the technical innovations, the performance of the vertical roller mill is comprehensively improved.

Description

A vertical roller mill and a manufactured sand production system Technical Field

[0001] This invention belongs to the field of grinding equipment technology, and particularly relates to a vertical roller mill and a manufactured sand production system. Background Technology

[0002] Vertical roller mills are widely used bed grinding equipment, integrating crushing, drying, grinding, classification, and conveying, with high grinding efficiency and low energy consumption as their main advantages. However, a series of problems exist in actual operation, affecting their stability and grinding efficiency.

[0003] In the operation of vertical roller mills, the stability of the material bed is a critical issue. While for specific, uniformly sized or highly moist materials, a relatively stable material bed can be maintained by setting a baffle ring of a certain height, this often comes at the cost of reduced grinding efficiency. For materials with varying particle sizes, especially mixtures and dry powders, the height of the baffle ring needs to be constantly adjusted. This leads to increased fluctuations in the material bed thickness, which in turn exacerbates mill vibration, making it difficult for the equipment to maintain stable operation.

[0004] The classifying efficiency of the air classifier located at the top of the vertical roller mill is also affected by various factors, such as the classifying concentration, the fineness of the finished product, and the fineness of the material entering the classifier. Because the grinding zone of the mill is constantly in a dynamic equilibrium state and is influenced by multiple factors, the circulating load of the material within the vertical roller mill is relatively large. For materials such as cement and slag, the circulating load is even greater, causing the feed concentration into the classifier to fluctuate constantly, thus affecting the classifier's efficiency and preventing it from operating at its optimal state.

[0005] In the structural design of vertical roller mills, although some patent publications have proposed some solutions, such as double-layer grinding discs, process-graded grinding structures, and parallel grinding partial-graded grinding structures, these structures are complex and difficult to implement in mechanical design. Moreover, when vertical mills are made larger, the connecting structures will occupy frame space, limit the number of grinding rollers, and are not conducive to optimized design.

[0006] Due to the varying particle sizes of materials, especially dry powders and mixtures, the height of the retaining ring is not fixed and needs to be adjusted regularly, making it difficult to form a stable material layer. Large fluctuations in the material layer thickness can easily lead to excessive mill vibration and unstable operation. The classifier located at the top of the vertical roller mill is primarily affected by the classifier concentration, the fineness of the finished product, and the fineness of the material entering the classifier. Because the grinding zone of the vertical roller mill is constantly in a dynamic equilibrium and is highly susceptible to multiple factors such as material particle size, feed rate, and the amount of coarse powder returned from the classifier, the material circulation load within the vertical roller mill is relatively high. For raw materials, the circulation load is only 4-5 times higher, while for cement and slag, the circulation load is even greater. Therefore, the feed concentration entering the classifier is constantly fluctuating, causing the classifier's classification efficiency to consistently fall short of its optimal state. Since the vertical roller mill is a highly integrated piece of equipment, the material being ground below the grinding rollers comprises three units: one unit for fresh material, one unit for semi-finished material after grinding, and one unit for finished material. Since vertical roller mills are bed mills, in order to maintain a relatively stable material layer and prevent excessive mill vibration during operation, it is necessary to ensure that fresh feed, finished products, and semi-finished products are within a reasonable ratio range. At the same time, the rotational speed and grinding pressure of the grinding discs must also be considered.

[0007] Chinese patent publications CN204865995U, CN204865996U, and CN204865997U disclose a double-layer grinding disc grading grinding structure for a vertical roller mill, a process grading grinding structure for a vertical roller mill, and a parallel grinding section grading grinding structure for a vertical roller mill, respectively. Their common feature is the design of two types of grinding rollers, utilizing a classifier for material return, allowing each type of roller to perform its specific function, achieving a stable material layer and improving grinding efficiency. However, due to their complex structure, they are difficult to implement mechanically. Chinese patent publications CN103480460B, CN102794214A, CN1112857A, CN102802799B, and CN106040366A all disclose similar stable material layer designs, including auxiliary rollers for pre-compressing materials. When vertical roller mills are scaled up, this connection structure occupies space in the mill frame, limits the number of grinding rollers, and does not utilize the optimized design of vertical roller mills.

[0008] Therefore, considering factors such as the stability of the feed bed, powder selection efficiency, and the complexity of the mechanical structure design, it is necessary to redesign the vertical roller mill. Summary of the Invention

[0009] To address the problems of existing vertical roller mills in terms of material bed stability, powder classification efficiency, and mechanical structure design, this invention provides a vertical roller mill and a manufactured sand production system.

[0010] The present invention is implemented as follows: a vertical roller mill, including a grinding section, the grinding section including a grinding disc and grinding rollers, characterized in that: it includes a pre-grinding section and an adaptive material blocking adjustment section.

[0011] The pre-grinding section includes a feeding center shaft and grinding units. The feeding center shaft is located above the grinding disc and is used to guide the material to be ground to the center of the grinding disc. N grinding units are evenly distributed around the feeding center shaft, and each grinding unit has a pre-grinding section that contacts the grinding end face of the grinding disc.

[0012] The adaptive material blocking adjustment section includes a rocker arm sealing frame, a material blocking device, and a linkage assembly. The rocker arm sealing frame forms a support for mounting the grinding roller. The exterior of the rocker arm sealing frame is mounted on the frame of the roller mill via a rocker arm, and the grinding roller is installed inside the rocker arm sealing frame. The material blocking device includes a fixed material blocking device and a sliding material blocking device that is vertically movable and connected to the fixed material blocking device. The fixed material blocking device and the sliding material blocking device form a enclosure structure around the grinding roller. The linkage assembly is connected to the rocker arm sealing frame and the sliding material blocking device. The rocker arm sealing frame, which moves upward internally, drives the sliding material blocking device to move in the opposite direction through the linkage assembly.

[0013] In the above technical solution, preferably, the pre-grinding section includes a pressurizing device, which is connected to the grinding unit and applies pressure to the grinding unit against the grinding end face of the grinding disc.

[0014] In the above technical solution, preferably, the grinding units are centered on the feeding center axis and radiate outwards, and the grinding units are evenly distributed above the grinding disc; the grinding units are arranged between the roller gaps of the grinding rollers of the vertical roller mill.

[0015] In the above technical solution, preferably, the grinding unit includes a support shaft and a pre-grinding roller body. The axis of the support shaft is horizontally arranged, and the pre-grinding roller body is provided with a pre-grinding part that contacts the grinding end face of the grinding disc. The pre-grinding roller body is fixed by one end of the support shaft, and the other end of the support shaft is connected to the feeding center shaft.

[0016] In the above technical solution, preferably, the pressurizing device is arranged around the outside of the feeding center shaft, the upper end of the pressurizing device is fixed to the upper part of the feeding center shaft, the lower end of the pressurizing device is connected to the support shaft of the grinding unit, and the pressurizing device applies vertical downward pressure to the support shaft.

[0017] In the above technical solution, preferably, a sliding sleeve that slides axially is fitted at the lower end of the feeding center shaft, the end of the support shaft is fixed to the sliding sleeve, the feeding center shaft is provided with a flange, and the pressure device is a compression spring provided between the flange of the feeding center shaft and the sliding sleeve.

[0018] In the above technical solution, preferably, the fixed baffle is disposed above the grinding disc, and the fixed baffle is arranged in segments along the outer edge of the grinding disc; the sliding baffle is embedded in the fixed baffle, and the width of the sliding baffle is smaller than the width of the fixed baffle.

[0019] In the above technical solution, preferably, the linkage component includes a fixed bracket, a lever connecting rod, and a lifting connecting rod. The fixed bracket is installed on the housing of the vertical roller mill. The fixed bracket is fitted with a lever pin through a long slot. The lever connecting rod is connected to the lever pin. One end of the lever connecting rod is hinged to a rocker arm sealing frame. The other end of the lever connecting rod is hinged to the upper end of the lifting connecting rod. The lower end of the lifting connecting rod is hinged to the sliding stop device.

[0020] In the above technical solution, preferably, the corresponding contact surfaces of the sliding stop device and the fixed stop device are provided with magnetism to make the contact surfaces fit together, the fixed stop device is provided with an inner vertical side stop surface, and the outside of the fixed stop device is provided with a slope surface, which is an inclined surface formed from the inside to the outside.

[0021] Advantages and effects:

[0022] This invention introduces several innovative technologies into the design of vertical roller mills to solve a series of problems existing in the prior art in terms of material bed stability, grinding efficiency and structural complexity.

[0023] Firstly, by setting up a pre-sorting section, the outer edge of the grinding disc is used as a pre-treatment area to pre-sort the semi-finished and finished products that are ground and ejected from the grinding disc. This effectively reduces the material concentration entering the cavity of the support unit and improves the powder classifier's efficiency. Especially for materials with high specific surface area and requiring ultrafine powder selection, the pre-sorting section becomes a key step, helping to improve the performance of the entire grinding system.

[0024] Secondly, the application of the adaptive baffle adjustment device plays a crucial role in real-time adjustment of the height of the sliding baffle. By adjusting the height of the baffle, the flow rate and residence time of the material on the grinding disc are controlled, achieving a stable material layer formed within a relatively reasonable ratio range for fresh feed, semi-finished products, and finished products. This technology not only maximizes the grinding capacity of the vertical roller mill but also reduces over-grinding, significantly improving grinding efficiency.

[0025] Furthermore, the introduction of a pre-grinding section, by scattering several grinding sections or annular grinding rings above the grinding disc, degasses, crushes, and pre-grinds the fresh material. This design effectively reduces the grinding intensity of the material entering the grinding rollers and prolongs the residence time of the material on the grinding disc, allowing the material to be ground more thoroughly. The pre-grinding process not only reduces the projected pressure of the grinding rollers and increases the first-pass yield, but also improves the particle size distribution of the finished product, providing strong support for the efficient operation of the mill.

[0026] Finally, the innovative designs proposed in this invention, including the adaptive feed adjustment device, pre-sorting section, and pre-grinding section, have resulted in significant economic benefits for the vertical roller mill during field operation. Laboratory studies and field data statistics show that system output has increased by 8-10%, and grinding power consumption has decreased by more than 5%. The mill's stability has been significantly improved, with vibration values ​​decreasing by 10-40% and horizontal and vertical amplitudes decreasing by 30-50%. Simultaneously, particle size distribution has been improved; for raw material grinding, the finished product particle size distribution is narrower, and the particle distribution n-value has decreased by 5-10%; for cement grinding systems, the finished product particle size distribution is wider, and the particle distribution n-value has increased by 8-10%, improving the quality and performance of the finished product. The operating roller pressure has been significantly improved, with the mill's projected pressure increasing by 10-30%, enhancing the vertical mill's grinding capacity. Powder classification efficiency has increased by 8-15%, and clarity has improved by 10-15%. These positive effects make the mill operation more efficient and stable, increasing the effective power of the mill by 5-10%. This has brought about an important technological breakthrough in improving the performance of vertical roller mills and reducing engineering investment. Vertical roller mills with high powder classification efficiency, especially for ultrafine materials, have important practical value.

[0027] Therefore, through multifaceted technological innovation, this invention comprehensively improves the performance of vertical roller mills, solves the problems existing in the prior art, and brings new solutions to the grinding process in industrial production.

[0028] A second objective of this invention is to provide a manufactured sand production system, comprising the aforementioned vertical roller mill, a raw material buffer silo, a classifier, a vibrating screen, and a descaling mechanism; the descaling mechanism includes a cyclone separator and a circulating fan; the outlet of the raw material buffer silo is connected to the feed inlet of the vertical roller mill; the discharge outlet of the vertical roller mill is connected to the vibrating screen; the vibrating screen returns the oversized powder particles to the vertical roller mill via an elevator; the air outlet of the vertical roller mill is connected to the inlet of the classifier; the air outlet of the classifier is connected to the cyclone separator; and the air outlet of the cyclone separator is connected to the circulating fan. Attached Figure Description

[0029] Figure 1 is a schematic diagram of the structure of the present invention;

[0030] Figure 2 is a schematic diagram showing the location of the pre-grinding section in this invention;

[0031] Figure 3 is a schematic diagram of the pre-grinding section in this invention;

[0032] Figure 4 is a cross-sectional view of the pre-grinding section in this invention;

[0033] Figure 5 is a diagram showing the non-uniform symmetric curve construction of the grinding unit of the vertical roller mill pre-grinding device provided in Embodiment 1 of the present invention.

[0034] Figure 6 is a schematic diagram of the adaptive adjustment part in this invention;

[0035] Figure 7 is a schematic diagram of the installation position of the adaptive adjustment part in this invention;

[0036] Figure 8 is a top view of the adaptive adjustment part in this invention;

[0037] Figure 9 is a side elevation view of the adaptive adjustment part in this invention;

[0038] Figure 10 is a schematic diagram of the material blocking device in the adaptive adjustment part of the present invention;

[0039] Figure 11 is a structural schematic diagram of the slope-shaped material blocking device in the adaptive adjustment part of the present invention;

[0040] Figure 12 is a schematic diagram of the adaptive adjustment step-shaped sliding baffle device in this invention.

[0041] Figure 13 shows the W values ​​corresponding to different displacements (converted to angles) of the mill under optimal operating conditions;

[0042] Figure 14 is a front sectional view of Embodiment 2 of this application;

[0043] Figure 15 is a schematic diagram of the installation structure of the annular inner diaphragm and the annular outer diaphragm in this application;

[0044] Figure 16 is a schematic diagram showing the positional relationship between the air inlet duct, the sorting duct, and the rising duct in this application;

[0045] Figure 17 is a schematic diagram of the rising air duct in this application;

[0046] Figure 18 is a schematic diagram of the positional geometric parameters of the annular inner diaphragm and the annular outer diaphragm in this application;

[0047] Figure 19 is a schematic diagram of the pre-grinding section in Embodiment 3 of this application;

[0048] Figures 20 and 21 are comparative experimental results of Embodiment 3 of this application;

[0049] Figure 22 is a structural schematic diagram of Embodiment 4 in this application;

[0050] Figure 23 is a structural schematic diagram of Embodiment 5 of this application;

[0051] Figure 24 is a structural schematic diagram of Embodiment Six in this application;

[0052] Figure 25 is a structural schematic diagram of Embodiment 7 of this application. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0054] To address the problems of material bed stability, powder classification efficiency, and mechanical structure design in vertical roller mills, this invention provides a vertical roller mill and a manufactured sand production system. Through multiple technological innovations, this vertical roller mill comprehensively improves its performance, solves the problems existing in the prior art, and brings a new solution to the grinding process in industrial production. To further illustrate the structure of this invention, a detailed description is provided below in conjunction with the accompanying drawings:

[0055] Example 1

[0056] Please refer to Figure 1. A vertical roller mill includes a housing 1 and a grinding section located inside the housing. The grinding section is the core of the entire equipment and represents existing known technology for vertical roller mills. It is responsible for grinding materials on a grinding disc. This unit includes a grinding disc 2, grinding rollers 3, and a grinding area above the grinding disc. Through the rotation and downward pressure of the grinding rollers, the material is squeezed and rubbed on the grinding disc, ultimately being ground into fine powder. In this embodiment, specifically, the grinding section is equipped with grinding rollers, a grinding disc, and a transmission device. The grinding rollers are positioned above the grinding disc. The grinding section also includes a frame, a hydraulic cylinder, an upper rocker arm, a lower rocker arm, a main motor, and a reducer. One end of the hydraulic cylinder is mounted on the frame, and the other end is connected to the lower rocker arm. The upper rocker arm is connected to the grinding rollers. The main motor and the reducer form a transmission mechanism that drives the grinding disc to rotate.

[0057] The grinding rollers are positioned above the grinding disc, with each roller having a conical angle of no more than 20°. The total projected area of ​​the grinding rollers on the grinding disc is 20-35% of the disc's area. Increasing the projected area increases the yield per pass, and combined with increased rotational speed and timely discharge of the ground material from the mill, reduces the amount of fine powder generated. The vertical roller mill in this embodiment employs a rocker arm tilting roller structure, allowing the grinding rollers to be directly tilted outside the mill for maintenance. The roller sleeves are made of weld overlay material, facilitating online welding.

[0058] The main factors affecting vertical roller mills include the grinding disc rotation speed, the centrifugal force exerted on the material on the grinding disc, and the grinding pressure. Among these:

[0059] 1) The grinding disc rotation speed of the vertical mill for manufactured sand is calculated using the following formula:

[0060]

[0061] Where: n is the grinding disc rotation speed, r / min;

[0062] K is an empirical coefficient, dimensionless, and K takes a value of 48-60;

[0063] D is the diameter of the vertical mill disc, in meters (m).

[0064] The grinding disc speed of the vertical roller mill is 1.05 to 1.35 times that of the traditional vertical mill grinding disc speed, which is 25 to 35 r / min. The increase in speed can shorten the residence time of material particles on the grinding disc, reduce the number of times the particles are ground, and reduce the amount of excessively fine powder generated.

[0065] 2) The centrifugal force exerted on the material on the grinding disc is calculated using the following formula:

[0066]

[0067] Where: F is the centrifugal force (N) exerted on the material on the grinding disc;

[0068] m is the particle mass, in kg;

[0069] V is the circumferential speed of the grinding disc, in m / s;

[0070] R is the radius of the grinding disc, in meters (m).

[0071] It can be seen that when V is larger, the centrifugal force on the material is greater, the residence time on the grinding disc is shorter, and the material can be discharged from the mill in time after one grinding, reducing the number and degree of over-grinding of the material.

[0072] 3) The grinding pressure of the material is calculated using the following formula:

[0073]

[0074] Where: P is the grinding pressure, MPa;

[0075] F represents the hydraulic cylinder grinding pressure, in N;

[0076] S1 is the effective area of ​​the hydraulic oil in the hydraulic cylinder, in meters. 2 ;

[0077] S2 is the projected area of ​​a single grinding roller on the grinding disc, in meters. 2 ;

[0078] k is the rocker arm coefficient of the vertical roller mill, which is dimensionless and represents the structural space design value. The value of k ranges from 0.6 to 0.8.

[0079] Obviously, the greater the grinding pressure on a material, the easier it is to crush it.

[0080] 4) The diameter of the grinding disc is selected according to the actual output and the different raw materials. The relationship between the grinding disc diameter and the grinding capacity is as follows:

[0081]

[0082] Where: D0 is the diameter of the grinding disc of the vertical roller mill, in meters;

[0083] Q R The output of the vertical roller mill is expressed in t / h.

[0084] k is a coefficient for vertical roller mills, dimensionless, and related to the type of material being ground.

[0085] 5) The air volume of the vertical roller mill should be selected according to the actual output, raw materials, and finished product fineness. The selection calculation can be performed according to the following formula:

[0086]

[0087] Where: Q is the output air volume of the vertical roller mill, in m³. 3 / h;

[0088] D is the diameter of the grinding disc of the vertical roller mill, in meters;

[0089] V is the nominal wind speed of the vertical roller mill disc, in m / s. Depending on the material, V ranges from 4 to 12 m / s.

[0090] It also includes a pre-grinding section and an adaptive feed adjustment section. Both the pre-grinding section and the adaptive feed adjustment section are functional units housed inside the vertical roller mill casing. The pre-grinding section is used to pre-treat fresh materials to reduce the grinding intensity of the material entering the grinding section of the rollers. The adaptive feed adjustment section is used to control the flow rate and residence time of the material on the grinding discs to form a stable material layer. This helps to maximize the grinding capacity of the vertical roller mill and reduce over-grinding.

[0091] Please refer to Figures 2-4. The pre-grinding section includes a grinding disc, a feeding center shaft 5, a grinding unit 6, and a pressurizing device 7.

[0092] The grinding disc is a core component of the vertical roller mill. It is a rotating component installed inside the vertical roller mill and is driven to rotate by a drive unit.

[0093] The feeding center shaft is located above the grinding disc and is used to guide the material to be ground to the center of the grinding disc. The feeding center shaft is a vertical guide cylindrical tube component located at the center of the vertical roller mill. In this embodiment, a classifier is installed at the upper part of the casing, and the pre-grinding section uses the central return cone of the classifier as the feeding center shaft. The position of the feeding center shaft is called the feeding center.

[0094] N grinding units are evenly distributed around the central feeding shaft. Each grinding unit has a pre-grinding section that contacts the grinding end face of the grinding disc. The grinding units are multiple individual grinding components arranged in a ring; specifically, N grinding units are radially radiating outwards from the center above the grinding disc. Through the rotation of the grinding disc, the grinding units achieve relative circular rotation around the center of the disc, thus venting, crushing, and pre-grinding the material to be ground, which is conveyed to the center of the grinding disc from the lower end of the central feeding shaft.

[0095] It also includes a pressurizing device, which is connected to the grinding unit and applies pressure to the grinding end face of the grinding disc. Utilizing the weight of the grinding unit and the pressurizing device installed at the feeding center, and with the help of the internal friction between the materials, the vertical roller mill performs circular motion by feeding fresh materials through the feeding center for crushing and pre-grinding.

[0096] The grinding disc can be a traditional, integrated, single horizontal grinding disc, where the shape of the grinding area corresponds to the shape of the grinding rollers in the roller mill. The grinding units in the pre-grinding section are distributed on the inner side above the grinding disc, while the grinding rollers are distributed on the outer side, with the grinding units and rollers arranged alternately in a circumferential pattern. Alternatively, the grinding disc can be radially stepped, with the inner grinding units positioned above the outer grinding rollers, and the inner grinding units having a baffle device around their perimeter. This allows a material layer of a certain thickness to be formed in the pre-grinding section, thus achieving the purpose of pre-grinding. In this embodiment, specifically, in the pre-grinding section, the grinding units are evenly distributed above the grinding disc in a radiating pattern, centered on the feeding axis. The number of grinding units can be n = 2, 3, or 4, depending on the material characteristics and processing capacity. The grinding units are evenly distributed between the roller gaps of the vertical roller mill, and the structure and distribution of the vertical roller mill rollers are existing known technologies. In this embodiment, there are three grinding units and three grinding rollers, arranged in a circumferential, staggered pattern. The grinding unit is equipped with a pre-grinding roller body that contacts the grinding disc. In this embodiment, the sliding diameter of the pre-grinding roller body can be designed according to 20% to 50% of the diameter of the grinding roller, and its width can be designed according to 20% to 40% of the diameter of the grinding unit. The grinding diameter of the pre-grinding roller body moving in a circle along the grinding disc can be designed according to 50% to 80% of the diameter of the grinding disc.

[0097] In this embodiment, the grinding unit includes a support shaft and a pre-grinding roller. The axis of the support shaft is horizontally positioned, and the pre-grinding section is located on the pre-grinding roller. The pre-grinding roller is fixed at one end of the support shaft, and the other end of the support shaft is connected to the feeding center shaft. The pre-grinding roller rotates relative to the center of the grinding disc. Simultaneously, the pre-grinding roller can be designed as a rotary roller, capable of self-rotation while moving around the center of the grinding disc. The contact surface between the pre-grinding roller and the grinding disc liner is constructed with a non-uniform, symmetrical arc shape, which facilitates rapid pre-grinding of the material and, after pre-grinding, rapid conveying to the grinding roller for high-pressure grinding, thereby improving grinding efficiency.

[0098] The method for constructing the non-uniform symmetric curve M is shown in Figure 5: the control points of curve M are three circle centers, namely the first circle center control point O1, the second circle center control point O2, and the third circle center control point O3.

[0099] The width of curve M is W, which is also the width of the grinding unit, and the thickness is H. The highest point of tangency of curve M is C. The two endpoints A and B of the width W of the grinding unit intersect the horizontal direction of the highest point of tangency C at D and F, respectively. The angle bisectors of line segments AD and AC, and CD and CA intersect at point E. Similarly, the angle bisectors of line segments BF and BC, and CF and CB intersect at point G. Points E and G are the projection points of line segments AC and BC, respectively, and intersect line segment AB at O2 and O3, respectively. They also intersect point C at O1, the projection point of line segment AB. With O1, O2, and O3 as centers and AO2, CO1, and BO3 as radii, draw three arcs: AE, EG, and GB. These three arcs constitute curve M.

[0100] The pressurizing device surrounds the outside of the feeding center shaft, with its upper end fixed to the upper part of the feeding center shaft and its lower end connected to the support shaft of the grinding unit. The pressurizing device applies vertical downward pressure to the support shaft. The pressurizing direction is perpendicular to the center shaft. The pressurizing device can be a disc spring or a ring cylinder. Based on the particle size, moisture content, and flow characteristics of the material, the pre-grinding system is preset to 20%~80% of the grinding roller pressure via a hydraulic system. Simultaneously, the weight of the grinding section is used to degas, crush, and pre-grind the fresh material from the feeding center. One end of the support shaft is installed at the lower part of the feeding center, and the other end is connected to the roller shaft of the pre-grinding roller body of the grinding unit, serving as the connecting mechanism between the pressurizing device and the grinding unit.

[0101] Specifically, an axially sliding sleeve is fitted at the lower end of the feeding center shaft, and the end of the support shaft is fixed to the sleeve. The pressure device is a compression spring located between the flange of the feeding center shaft and the sleeve. The spring force transmits the grinding pressure to the grinding unit for pre-grinding. In this embodiment, the horizontal angle between the support shaft and the axis of the pre-grinding roller is 5°-20°, depending on the different material characteristics (particle size, flowability, and angle of repose).

[0102] In this embodiment, H is the material's engagement height, which is also the maximum engagement diameter of the pre-grinding roller body. Generally, H is taken to be no greater than the maximum diameter of the material. The sliding diameter of the pre-grinding roller body d = 0.2~0.5 times the grinding disc diameter, and the width of the pre-grinding roller body B = α is the angle of repose of the material, which depends on the characteristics of the material. The grinding diameter D' of the pre-grinding roller body is 0.2 to 0.8 times the diameter of the grinding disc. The height H' of the pre-grinding roller body is 0.2 to 1.0 times the height of the middle shell. The contact surface between the pre-grinding roller body and the grinding disc liner is constructed in a non-uniform symmetrical arc shape. The material of the pre-grinding roller body is ductile iron QT400-18 or cast steel ZG20SiMn. The roller sleeve of the pre-grinding roller body is divided into a base material and a wear-resistant layer. The base material is cast steel ZG20SiMn, and the wear-resistant layer is a weld overlay material with a thickness of 40 to 60 mm and a hardness of 60 ± 5 HRC. The wear-resistant liner is also divided into a base material and a wear-resistant layer. The base material is cast steel ZG20SiMn, and the wear-resistant layer is a weld overlay material with a thickness of 40 to 60 mm and a hardness of 60 ± 5 HRC.

[0103] In the above basic scheme, preferably, the height of the baffle ring of the pre-grinding disc is 2-8% of the diameter of the pre-grinding disc;

[0104] This pre-grinding section degasses, crushes, and pre-grinds the fresh material from the feeding center, reducing the grinding intensity of the material entering the grinding rollers and maximizing the rollers' capacity. It also alters the particle size distribution in the finished product; for materials with high particle size requirements, such as cement and slag, the content of 3-30μm particles can reach over 75%. Appropriate pre-grinding of fresh material increases the difficulty of material detaching from the grinding disc, prolongs the material's residence time on the disc, reduces the chance of material escaping, and ensures more thorough grinding. Adding a single grinding stage reduces the projected grinding pressure on the rollers by 20-50%, increases the yield of the vertical roller mill in one pass by 20-50%, and reduces the external circulation load by 20-50%, thereby reducing the need for auxiliary equipment and lowering project investment. The pre-grinding section increases the fine powder content carried into the classifier, reducing the classifier's load, increasing its efficiency by 20-60%, and decreasing its linear speed by 20-40%. In the pre-grinding section, the surface of the grinding unit adopts a non-uniform symmetrical arc shape, which is conducive to the rapid pre-grinding of materials. After pre-grinding, the material is quickly conveyed to the grinding roller for high-pressure grinding, thereby improving grinding efficiency.

[0105] As shown in Figure 6-11, the adaptive baffle adjustment device for vertical roller mills includes a rocker arm sealing frame, a baffle device, and a linkage component.

[0106] The rocker arm seal frame forms a support for mounting the grinding roller. The outside of the rocker arm seal frame is mounted on the frame of the roller mill via a rocker arm, and the grinding roller is installed inside the rocker arm seal frame.

[0107] The material blocking device includes a fixed material blocking device 8 and a sliding material blocking device 9 that is combined with the fixed material blocking device by vertical movement. The fixed material blocking device and the sliding material blocking device form a enclosure structure located around the grinding roller.

[0108] The fixed baffle is positioned above the grinding disc and arranged in segments along the outer edge of the disc. The diameter of the fixed baffle is slightly smaller than the outer diameter of the grinding disc, and the upper end of the fixed baffle is concave. The fixed baffle is segmented, with the number of segments matching the number of grinding rollers. The length of each segment covers both the feed and discharge ends of each grinding roller. The gap between every two segments is specially designed and calculated based on the material characteristics and the required fineness of the finished product, and is generally approximately 2 to 5 times the maximum particle size of the material. The sliding baffle is embedded in the middle of the fixed baffle, and its width is smaller than that of the fixed baffle. It is also arranged in segments, with the number matching the number of grinding rollers. The shape and gap size of each segment of the sliding baffle are specially designed and calculated according to the material characteristics and finished product fineness requirements. The sliding baffle can move vertically within the concave groove at the upper end of the fixed baffle. The sliding baffle and the fixed baffle are connected to an external air seal device through a small clearance fit. A certain amount and pressure of gas is introduced into this external air seal device to form an "air seal," preventing material dust particles from entering the cavity between the sliding baffle and the fixed baffle during mill operation, thus preventing the sliding baffle from malfunctioning. The sliding baffle and the fixed baffle are fitted with a small clearance. Through the connection of the external air seal device, a certain amount and pressure of gas is introduced into this cavity to form an "air seal," preventing material dust particles from entering the cavity between the sliding baffle and the fixed baffle during mill operation, thus preventing the sliding baffle from malfunctioning.

[0109] The sliding baffle device can adjust the baffle height and the gap between the grinding roller and the baffle device, thereby adjusting the particle size distribution of the material at the root of the baffle device and the amount of material accumulation at the root of the baffle device, which in turn affects the thickness of the material layer on the grinding disc and the grinding efficiency of the vertical roller mill.

[0110] As shown in Figure 11, in this embodiment, the corresponding contact surfaces of the sliding baffle and the fixed baffle are provided with magnets to ensure contact. They can adhere tightly to each other and slide freely due to the magnetism. The fixed baffle has an inner vertical side baffle surface and an outer slope. The slope is an inclined plane formed from the inside out, and the angle of inclination with the horizontal plane depends on the material's angle of repose, generally 0~60°. The sliding baffle has the same corresponding contact surface and a corresponding inclination angle. Alternatively, a magnetic device can be designed between the sliding baffle and the fixed baffle, with the fixed baffle being single-sided and lacking an outer baffle surface. The inner baffle surface is in close contact with the sliding baffle. Using the magnetic device, the sliding baffle can slide freely up and down along the fixed baffle. The inner bottom is designed as a "slope" to facilitate the timely removal of dust and material entering the baffle.

[0111] The sliding baffle can be designed in a stepped shape, as shown in Figure 12. The stepped sliding baffle is shorter than the fixed baffle and is placed above it. It can slide vertically up and down via the grooves or magnetic structure of the fixed baffle. The highest point of the stepped sliding baffle is directly below the grinding roller, decreasing sequentially towards the feed and discharge ends of the roller. The sliding baffle is positioned above the fixed baffle and can be configured in different shapes, such as a stepped shape, descending at equal intervals from the center of the grinding roller to both ends. Since the material layer at the bottom of the grinding roller is crucial for its stability, and the distance between the bottom of the grinding roller and the grinding disc baffle ring is the largest, a higher baffle ring is needed to ensure stable material layer formation. Therefore, installing a stepped sliding baffle further solidifies the stable formation of the material layer and further improves the grinding efficiency.

[0112] In this embodiment, specifically, the fixed baffle device has a wear-resistant layer on its concentric or inner side, the wear-resistant surface HRC≥50, and the wear-resistant layer thickness is 6~12mm. The width of the sliding baffle device is 20~80% of the width of the fixed baffle device, and the gap between each segment of the sliding baffle device is 60~80% of the average particle size of the material entering the mill. The length of each segment of the fixed baffle device is 1.1~1.5 times the diameter of the corresponding grinding roller, and the gap is 2~5 times the maximum particle size of the material. When the fixed baffle device and the sliding baffle device are configured as magnetic devices, the fixed baffle device is configured as a single-sided device, specifically an inner single-sided device, with a sloped bottom that tilts from the inside to the outside, and the tilt angle with the horizontal plane is 0~60°. In addition to the above methods, the fixed baffle device can be configured as a groove shape, and the internal cavity is configured as an air-sealed state.

[0113] The linkage component is connected to the rocker arm sealing frame and the sliding stop device. The rocker arm sealing frame, which moves upward inside, drives the sliding stop device to move in the opposite direction through the linkage component.

[0114] The linkage assembly includes a fixed bracket 10, a lever connecting rod 11, and a lifting connecting rod 12. The fixed bracket is installed on the housing of the roller mill. The fixed bracket is fitted with a lever pin through a long slot. The lever connecting rod is connected to the lever pin. One end of the lever connecting rod is hinged to a rocker arm sealing frame, and the other end of the lever connecting rod is hinged to the upper end of the lifting connecting rod. The lower end of the lifting connecting rod is hinged to a sliding stop device.

[0115] The fixed supports are two symmetrical supports extending horizontally inside the roller mill, fixed to the inner wall of the middle shell of the vertical roller mill. Two symmetrical fixed supports are installed on both sides of each rocker arm seal frame. The fixed supports have elongated slots of a certain length. Since the rocker arm seal frame's swing is a non-uniform up-and-down movement, these slots provide horizontal displacement space for the lever pin. The lever connecting rod is connected through these slots and the lever pin, which slides within them, and also serves as the fulcrum of the lever connecting rod, allowing vertical movement at both ends of the lever connecting rod.

[0116] One end of the lever link is hinged to the rocker arm seal frame via a pin, which is perpendicular to both the lever link and the side of the rocker arm seal frame. The other end of the lever link is connected to the upper end of the lifting link via another pin. The middle position of the lever link is fitted into the elongated slot of the fixed bracket via a lever pin. The tangential up-and-down displacement of the inner end of the rocker arm seal frame drives the two ends of the lever link to move in opposite directions, thereby driving the lifting link to move up and down in opposite directions. Through the fixed fulcrum fixed to the housing, the lever link transmits the tangential displacement of the grinding roller seal frame and can eliminate horizontal displacement. Utilizing the lever principle, the grinding roller seal frame and the sliding stop device can move vertically in opposite directions. In this embodiment, specifically, a fixed end connecting rod is fixed at the upper part of the sliding stop device, and the lower end of the lifting connecting rod is hinged to this end connecting rod, which plays the role of transmitting the upper and lower displacement, and can also buffer a certain amount of horizontal displacement. The upper end of the end connecting rod is connected to the lower end of the lifting connecting rod through a pin, and the other end is fixed to the sliding stop device of the stop device. Through the upper and lower displacement transmitted by the end connecting rod, the sliding stop device can move up and down in the vertical direction according to the up and down swing of the grinding roller sealing frame, thereby achieving the purpose of adjusting the height of the stop ring and the gap between the stop device and the large end of the grinding roller.

[0117] The working principle of this invention is as follows: When a vertical roller mill is running, if the material particles are widely dispersed, with varying particle sizes, a large feed flow rate, or significant material return from the classifier's central discharge cone, the material layer on the grinding disc will be thick. Fine powder in this layer will have difficulty leaving the grinding disc quickly, leading to instability, large fluctuations, and reduced grinding efficiency. If the roller pressure remains constant, the roller pressure per unit area decreases, resulting in insufficient grinding force. Simultaneously, the thicker material layer will lift the grinding rollers and rocker arm seals, causing them to shift upwards. This indicates that at this point, it is necessary to reduce the material layer thickness to improve grinding efficiency and stabilize the mill. The upward displacement of the grinding roller and rocker arm seal frame is achieved by using a lever pin in the long slot of the fixed bracket fixed on the middle shell as a fulcrum. Utilizing the lever principle, this drives the other end of the lever connecting rod to move downward. At the same time, the long slot in the fixed bracket can counteract the horizontal displacement of the rocker arm seal frame. The downward displacement of the inner end of the lever connecting rod drives the lifting connecting rod to move downward, which is then transmitted to the end connecting rod. The end connecting rod transmits the transmission to the sliding baffle device, which moves downward, thereby reducing the height of the baffle ring, reducing the material layer thickness, stabilizing the mill, and improving grinding efficiency.

[0118] Conversely, when the feed rate decreases, the particle size of the material decreases, or a certain amount of dry powder is mixed in, making it difficult for the material layer to form, the material layer will become thinner or more difficult to form during the operation of the vertical roller mill. This indicates that in this case, it is necessary to increase the height of the baffle ring to stabilize the mill, thereby improving grinding efficiency. The grinding roller and rocker arm sealing frame move downwards, and through the fixed bracket, lever connecting rod, end connecting rod and pin, the upward displacement is transmitted to the sliding baffle device using the lever principle, thereby achieving the purpose of increasing the height of the baffle ring, increasing the material layer thickness, stabilizing the mill and improving grinding efficiency.

[0119] By adjusting the height of the sliding baffle in real time, the flow rate and residence time of the material on the grinding disc are changed, and the proportion of new feed, semi-finished product and finished product on the grinding disc is adjusted. This allows the material to not only form a stable material layer, but also maximize the grinding capacity of the vertical roller mill. At the same time, the material can be quickly carried by the air to the classifier after being ground by the grinding rollers, reducing over-grinding and improving grinding efficiency.

[0120] Because the width of the sliding baffle is smaller than that of the fixed baffle, this invention can indirectly adjust the gap between the outer end face of the grinding roller and the baffle ring by adjusting the height of the sliding baffle. The downward movement of the sliding baffle reduces the gap between the outer end face of the grinding roller and the baffle ring, ensuring that the material can be compacted in the grinding area at the large end of the grinding roller. When the sliding baffle moves upward, it increases the gap between the outer end face of the grinding roller and the baffle ring, allowing the finished and semi-finished materials to escape the grinding disc in time and be sent to the classifier by the hot air at the air ring for sorting. This ensures the effectiveness of grinding, improves grinding efficiency, and reduces grinding power consumption.

[0121] The fixed baffle is mounted on the grinding disc and is divided into several units, the number of which matches the number of grinding rollers. A certain gap is left between each unit, i.e., between the grinding rollers, to facilitate the timely discharge of the semi-finished material after grinding and to prevent over-grinding. The size of the gap between the fixed baffle units is generally determined by the particle size of the material, typically 2 to 5 times the largest particle size.

[0122] In actual operation of a vertical roller mill, the particle distribution of the material layer transitions from small, dense particles at the bottom to larger, looser particles at the top. The material blocking device of this invention is a composite structure, with a fixed blocking device at the lower end and a sliding blocking device at the upper end, embedded within the fixed blocking device. Based on the material characteristics, and through experimental research or analysis of actual on-site operating data, the boundary point between the dense state of the bottom small particles and the loose state of the upper large particles is determined. This boundary point represents the minimum critical height of the fixed blocking device during stable mill operation, ensuring stable material layer formation. Based on the fluctuations in material layer formation and breakdown, the height of the blocking ring in the sliding blocking device is adjusted in reverse to compensate for the changes in material layer thickness caused by these fluctuations, ensuring efficient grinding at the theoretical critical point of grinding energy consumption.

[0123] By adjusting the particle size distribution of the material entering the grinding rollers, the particle size distribution is always kept in an optimal compact packing state, increasing the effective operating power of the mill and reducing wasted energy consumption. This allows for greater roller pressure to be applied and more material to be ground while maintaining stable operation. Due to the improved grinding effect, the amount of semi-finished product carried into the classifier is continuously reduced, leading to a decrease in the mill's circulating load and differential pressure. Simultaneously, the classifier's classification efficiency is improved, resulting in clearer classification and better separation of fine particles.

[0124] Through laboratory simulations or practical operational experience, the characteristics of single materials or mixtures of several materials are studied, including physical properties such as moisture content, particle size, particle size distribution, and grindability. Data statistics are used to record the optimal baffle height for grinding this material in a vertical roller mill, as well as the curves corresponding to the range of material layer fluctuations caused by particle size variations (statistically recorded using a level gauge). An adaptive baffle adjustment mechanism allows the rocker arm sealing frame to connect to the vertical roller mill's baffle device. By adjusting the position, length, lever ratio, and baffle device, the height of the sliding baffle device can be dynamically adjusted in real time, compensating for the optimal baffle height required due to material layer fluctuations during grinding. During mill operation, the adaptive baffle adjustment mechanism dynamically adjusts the height of the baffle device in real time, thereby compensating for frequent fluctuations in the grinding material layer thickness caused by varying particle sizes, achieving a near-zero material layer fluctuation amplitude, and laying the foundation for the efficient and stable operation of the vertical roller mill.

[0125] The connecting mechanism of this invention consists of several connecting rods, and the labels of each connecting rod and pin are shown in Figure 10. The displacement relationship between the rocker arm sealing frame and the material stop device is calculated as follows:

[0126] Step 1: F is the arc displacement of the grinding roller seal frame during the operation of the grinding roller, and the angle between it and the vertical direction is α;

[0127] Step 2: a and b are the lengths of the lever link at both ends with the lever pin in the long slot as the fulcrum. The total length of the lever link is a + b. F1 is the vertical displacement of the lever link connected to the lifting link, and the displacement is shown below:

[0128] F1=

[0129] Step 3: The length F2 of the long slot in the lever connecting rod is designed according to the following formula:

[0130] F2=

[0131] Step 4: β is the angle between the lifting link and the vertical direction, and its length is c;

[0132] Step 5: W represents the vertical displacement of the end link;

[0133] Step Six: Based on the arc displacement F of the grinding roller sealing frame during the operation of the vertical roller mill, derive the vertical displacement W of the sliding stop device. The conversion formula is shown below:

[0134]

[0135] The preferred technical solution is as follows:

[0136] The displacement W of the sliding stop device is 2-8% of the grinding disc diameter. The lever ratio a / b in the lever linkage is between 0.2 and 0.8, and the total length a+b of the lever linkage is 20-80% of the grinding roller diameter. The length c of the lifting linkage is 20-80% of the grinding roller diameter. The arc displacement of the grinding roller seal during grinding roller operation has an angle α with the vertical direction, ranging from 0-40°. The angle β between the lifting linkage and the vertical direction is 0-50°.

[0137] Based on laboratory research and field data accumulation, the angles and values ​​at each point are limited within a certain range, which can greatly reduce the debugging time of the adaptive adjustment device when grinding different materials.

[0138] Using simulation software, the actual operating conditions of the mill were simulated under different input values ​​F, a, b, c, α, and β. The optimal operating conditions of the mill were found to be: F = 3.6°, a = 1600mm, b = 2200mm, c = 3700mm, α = 15.4°, and β = 26.9°, as shown in Figure 13, which represents the W value of the mill corresponding to different displacements of F.

[0139] To compare the grinding efficiency of the adaptive feed adjustment device of the vertical roller mill, samples were taken along the vertical cross-section of the material layer formed on the grinding disc when the experimental mill was stopped suddenly. The finished product content P80 (80μm throughput) of the material was tested as a form of expression of grinding efficiency, as shown in Table 1 below.

[0140] Table 1. Material throughput (80μm) on the grinding disc under the same conditions.

[0141]

[0142] As shown in Table 1, under the same conditions, after installing the adaptive feed adjustment device, the amount of finished material on the grinding disc decreases under emergency stop conditions, with a 22% reduction in raw meal and a 31% reduction in cement powder. In terms of mill pressure difference, the raw meal decreases by 7% and the cement powder decreases by 6%. This indicates that the qualified finished material can be quickly removed from the grinding disc and enter the classifier for sorting, reducing the mill's circulating load and thus improving grinding efficiency.

[0143] To verify the actual efficiency of the adaptive material control device, Tianjin Institute conducted a comparative experiment using raw materials and installing the adaptive material control device. The results are shown in Table 2.

[0144] Table 2 Experimental Results of the Adaptive Material Gutter Adjustment Device

[0145]

[0146] As shown in Table 2, the conversion to R 80μm When the content is 12%, the power consumption of the vertical roller mill with adaptive feed adjustment device is reduced by about 0.8 kWh / t compared with the control sample, which is about 10% lower.

[0147] Example 2

[0148] The classifier located at the top of the vertical roller mill has its classification efficiency affected by various factors. It is particularly ineffective for classifying high-surface-area, ultrafine particles. Therefore, the current air duct design of the vertical roller mill is also a major reason for the high circulating load of powder particles within the mill. This makes it difficult to maintain a stable feed concentration in the classifier, often resulting in fluctuating operating conditions. This fluctuation in feed concentration prevents the classifier from operating at its optimal efficiency, impacting production efficiency and product quality in cement manufacturing. For the production of manufactured sand using a vertical roller mill, due to the gap between the grinding rollers, some unground powder particles are thrown out of the grinding disc by centrifugal force, resulting in a high number of circulations of powder particles in the grinding system and increased energy consumption. Therefore, this embodiment further improves the air duct structure of the vertical roller mill based on Embodiment 1. All other parts except the air duct structure are the same as in Embodiment 1, and will not be repeated here.

[0149] Referring to Figure 14, this vertical roller mill also includes a pre-sorting section and an ascending air duct. The pre-sorting section is used to pre-sort the semi-finished and finished products that are ground and ejected from the grinding discs. This helps reduce the material concentration entering subsequent units and improves the performance of the entire grinding system. The ascending air duct is responsible for conveying the ground material from the grinding section to the subsequent sorting and collection devices. This ensures smooth material transfer throughout the grinding process.

[0150] Please refer to Figures 15 and 16. The lower part of the casing has an air inlet 1-3, and the upper part of the casing has an air outlet 1-4. Specifically, the interior of the vertical roller mill casing has an air inlet duct 14 located below the grinding disc, a pre-sorting air duct 15 located below the outer periphery of the grinding disc, and an ascending air duct 16 located on the side of the casing. The air inlet duct connects to the air inlet. The pre-sorting air duct is equipped with baffles for dispersing the powder. The hot airflow introduced below the grinding disc passes sequentially through the air inlet duct, the sorting air duct, and the ascending air duct.

[0151] In this embodiment, specifically, the partition includes an annular inner partition 17 and an annular outer partition 18, and the shell includes an outer shell 1-1 and an inner shell 1-2. The annular inner partitions are spaced apart below the outer edge of the grinding disc, and the outer ring of the annular inner partition forms a stepped structure downward from the outer edge of the grinding disc. A circumferential air inlet is formed between the annular inner partitions. The air inlet of the vertical roller mill is circular or polygonal, arranged around the circumference of the grinding disc, and is composed of the cavity between the stepped structure formed by the radially outer part of the grinding disc and the annular inner partition. The bottom end of the air inlet is flush with the bottom of the grinding disc. Several circumferentially evenly distributed ribs 19 are connected to the bottom of the grinding disc. The ribs are air baffles and rotate with the grinding disc, thereby dividing the air inlet into several air inlet chambers. The air inlet is tangentially arranged in a volute shape or perpendicular to the bottom of the air inlet.

[0152] An annular outer partition is spaced apart on the lower inner side of the inner shell, forming an inverted stepped structure surrounding the positive stepped structure. A pre-sorting air duct is formed between the annular outer partition and the annular inner partition.

[0153] In this embodiment, the pre-sorting air duct is distributed in a ring along the grinding disc and is flush with the outer edge of the upper end of the grinding disc. The innermost ring-shaped inner partition with a positive stepped structure on the inner side of the pre-sorting air duct is connected to the outer edge of the grinding disc. The upper end of the outermost ring-shaped outer partition with an inverted stepped structure of the pre-sorting air duct is connected to the inner shell, and the lower end of the outer ring-shaped outer partition is connected to the outer shell. The two outer ring-shaped outer partitions are located outside the inlet of the rising air duct, and the inlet of the rising air duct is formed between the two outer ring-shaped outer partitions. Further, the outer ring-shaped outer partition at the top is connected to the inner shell, and the outer ring-shaped outer partition at the bottom is connected to the outer shell. The inner ring-shaped partition is mounted on the lower part of the grinding disc through ribs. The inner ring-shaped partition is coaxial with the grinding disc and is driven to rotate by the grinding disc. The inner ring-shaped partition and the outer ring-shaped partition are alternately spaced from the upper opening to the lower opening of the sorting air duct.

[0154] The pre-sorting air duct is composed of two sets of circular or polygonal conical rings that are separated from each other by a certain distance, overlap vertically, and are concentrically arranged. That is, it consists of a stepped screening group on the radial outside and a guide group on the radial inside. A screening zone is formed between the outer and inner ring groups, and the upper diameter of the screening zone is larger than the lower diameter of the screening zone.

[0155] After grinding, the powder particles are ejected from the grinding disc and fall onto the uppermost annular inner partition plate, which is a stepped structure. Due to gravity, they then fall onto the opposite annular outer partition plate, falling in a Z-shape alternately between the inner and outer partition plates. Hot airflow from the inlet duct enters through the gaps between the annular inner partition plates. During the fall, the powder particles are pre-sorted and dried by the hot airflow. The pre-sorted lighter powder particles are carried by the airflow through the annular outer partition plate into the rising air duct. The larger coarser powder falls to the next partition plate and is thoroughly dispersed and air-separated during each impact with the partition plate. After passing through all partition plates, the powder falling from the lower end of the pre-sorting air duct enters the discharge port of the vertical roller mill. The fine powder carried by the airflow from the annular outer partition plate into the rising air duct enters the outlet for secondary sorting.

[0156] Please refer to Figure 18. The specific parameters in the pre-sorting air duct of this embodiment are as follows:

[0157] (1) For the sorted material entering the pre-sorting air duct, the feed concentration Cs is 2.6~5.0kg / m 3 .

[0158] (2) The outer ring is made up of multiple rings, forming an inverted stepped structure. The length, angle, and spacing between the radial outer rings of each ring are the same. The number of inner rings is the same as the number of outer rings, forming a stepped structure. The length, angle, and spacing between the radial outer rings of each inner ring are the same.

[0159] (3) The partition is set as shown in Figure 9. The included angle A2 between the upper surfaces of the inner and outer annular partitions is 90°; the included angle A3 between the upper surface of the outer annular partition and the horizontal plane is 40°. <A3<80°。

[0160] (4) The width of the inner annular partition is L3, and the width of the outer annular partition is L4, 3 / 2 <L3 / L4<3 / 1。

[0161] (5) The number of inner annular partitions is the same as the number of outer annular partitions, both being N.

[0162] (6) The structure of the inner and outer annular baffles exists under the premise of the central air intake structure, thus forming a flow field structure that is conducive to the separation of coarse particles.

[0163] (7) The vertical distance between the lower edge of the inner annular partition and the upper surface of the adjacent outer annular partition is D1, and the vertical distance between the lower edge of the outer annular partition and the upper surface of the adjacent inner annular partition is D2. Then 1.5 / 1 <D1 / D2<2 / 1。

[0164] Please refer to Figure 17. The inner shell is located inside the outer shell, forming an upward air duct between them. A spiral baffle 20 is provided between the outer and inner shells, creating a spiral upward air duct around the centerline of the outer shell. The upward air duct connecting the pre-sorting air duct and the outlet of the vertical roller mill is configured as a cavity. This cavity can serve as an upward air duct for conveying air and materials, which not only reduces the long-term erosion of the internal components of the vertical roller mill by air, extending its service life and reducing routine maintenance, but also optimizes the flow field distribution and reduces local eddies for the rising gas, thus promoting local settling.

[0165] In this embodiment, the classifier installed between the grinding section and the air outlet of the vertical roller mill is a dynamic classifier 13, and the air outlet of the dynamic classifier is the air outlet of the vertical roller mill. The dynamic classifier at the top of the vertical roller mill is a sorting drum mechanism, with the sorting drum being the main component. Its working principle is to feed the already ground raw materials into the rotating sorting drum. During the rotation of the sorting drum, due to centrifugal force, finer particles are pushed to the outer periphery of the sorting drum, while coarser particles move inward. The finer particles are discharged from the air outlet at the top of the outer shell under the action of airflow, while the coarser particles fall onto the grinding disc for re-grinding.

[0166] The air inlet of the dynamic air classifier is composed of an inner shell and an outer shell that form the rising air duct. The upper end of the inner shell is connected to the bottom of the air inlet of the dynamic air classifier, and the upper end of the outer shell is connected to the upper end of the air inlet of the dynamic air classifier. In this embodiment, by adding a dynamic air classifier, the vertical roller mill can perform multi-stage separation, improve separation efficiency, and reduce the system's circulating load.

[0167] Example 3

[0168] Please refer to Figure 19. Unlike Embodiment 2, the grinding unit provided in this embodiment is annular, surrounding the central axis of the classifier's central return cone. A pressurizing device is installed on the upper part of the classifier's central return cone, and the annular grinding unit is installed at the lower part. Through the pressurizing device, based on the particle size, moisture content, and flow characteristics of the material, and utilizing the weight of the grinding unit itself, a hydraulic system is used to preset the pre-grinding system pressure to 20-80% of the grinding roller pressure. This allows for the degassing, crushing, and pre-grinding of the fresh material from the classifier's return cone. The contact surface between the annular grinding unit and the grinding disc liner is constructed in a non-uniform, symmetrical arc shape, which facilitates rapid pre-grinding of the material. After pre-grinding, the material is quickly conveyed to the grinding roller for high-pressure grinding, improving grinding efficiency.

[0169] To verify the actual effect of the vertical roller mill pre-grinding structure, clinker was used as raw material, with 100% of the clinker particle size less than 30mm. Grinding experiments were conducted on the traditional grinding structure, the grinding unit of Example 2, and the annular pre-grinding structure unit in this example. The thickness of the material layer and the particle size distribution on the grinding disc after exiting the pre-grinding structure unit were measured under different grinding time conditions. The specific results are shown in Figures 20 and 21. As can be seen from the figures, under the same conditions, with the extension of grinding time, the material layer thickness of the grinding unit of Example 2 and the annular grinding unit in this example is lower than that of the traditional form. At the same time, the 45μm content is significantly reduced, which improves the grinding efficiency.

[0170] Using cement clinker as raw material, grinding experiments were conducted on the grinding unit and the annular pre-grinding structure of Example 1, targeting the traditional grinding structure. The experimental results are shown in Table 3 below.

[0171] Table 3 Comparison of grinding effects of different pre-grinding structures under the same conditions

[0172]

[0173] Table 3 shows that: with a specific surface area of ​​3200 cm² 2 / g is the power consumption benchmark. Compared with the annular grinding unit of this embodiment, the grinding unit of Example 2 has a power consumption of ~3.0kWh / t lower than the traditional structure. At the same time, the grinding unit of Example 2 has better performance.

[0174] To compare the practical application effects of a vertical roller mill, experiments were conducted in an experimental workshop using TRM3.6 and TRM5.6 vertical roller mills, with cement and raw materials as raw materials. The results are shown in Table 4 below:

[0175] Table 4 Statistical Analysis of Experimental Results

[0176]

[0177] According to the experimental statistics in Table 4, under the same conditions, compared with the existing traditional vertical roller mill, the output is increased by 5-10%, the main motor power consumption is reduced by 10-15%, the mill resistance is reduced by 10-15%, and the mill operation stability is significantly improved, thus improving the technical effect of grinding efficiency.

[0178] Example 4

[0179] Please refer to Figure 22, which illustrates an ultrafine product grinding production system. Fresh powder particles are fed into a vertical roller mill through a raw material buffer silo 21, while a small amount of coarse powder particles discharged from the vertical roller mill can be mixed in via an elevator 22. The outlet of the vertical roller mill is connected to a dust collection device 23, through which ultrafine powder particles are collected as finished products. A circulating fan 24 is connected to the outlet of the dust collection device, and the hot air from the circulating fan is split into two paths: one path is used as circulating air and enters the vertical roller mill 25 for reuse, while the other path is directly discharged to the chimney 31. This system improves sorting efficiency and accuracy through multi-stage gradient sorting, enables product particle size control, reduces system circulating load, lowers system energy consumption, reduces workshop height, and saves investment costs.

[0180] Example 5

[0181] Please refer to Figure 23, which illustrates a manufactured sand production system using a vertical roller mill according to Embodiment 2. The system includes a raw material buffer silo 21, a vertical roller mill 14 (Embodiment 2), a classifier 30, a vibrating screen 26, and a descaling mechanism 27. The descaling mechanism includes a cyclone separator 27-1 and a circulating fan 24. The outlet of the raw material buffer silo is connected to the powder particle inlet of the vertical roller mill. The bottom outlet of the vertical roller mill is connected to the vibrating screen 26, which returns the oversized powder particles to the vertical roller mill via an elevator 22. The air outlet of the vertical roller mill is connected to the inlet of the classifier, the air outlet of the classifier is connected to the cyclone separator, and the air outlet of the cyclone separator is connected to the circulating fan.

[0182] After being crushed, ground, and pre-sorted by the vertical roller mill 25, the powder particles enter the sorting equipment such as vibrating screen and air classifier, realizing the efficient, low-energy consumption, and clean production of manufactured sand.

[0183] This embodiment also includes a flow stabilizing chamber, which ensures the stability of the powder particles entering the mill, improves the crushing and grinding efficiency of the vertical mill, reduces system output fluctuations, ensures stable system operation, improves energy utilization, reduces production energy consumption, improves equipment operation safety, and reduces the failure rate.

[0184] Raw materials enter the vertical roller mill from the raw material buffer silo via a conveyor belt. After grinding and pre-sorting, the coarse particles move downwards under gravity, while the de-powdered particles enter the vibrating screen. The vibrating screen has screen holes of a certain size. Particles that meet the size requirements pass through the vibrating screen and enter the finished product, forming finished sand. In this example, the vibrating screen can be set with three screen hole sizes according to different needs, such as 4.75mm, 2.36mm, or 1.18mm. Accordingly, particles smaller than or equal to 4.75mm, 2.36mm, or 1.18mm are used as finished sand. Particles that do not meet the requirements and are larger than the screen hole size return to the vertical roller mill for grinding and the next cycle. Fine powder smaller than 0.075mm or 1.18mm from the outlet of the vertical roller mill moves upward under the action of gas. The gas carries the fine powder from the classifier into the cyclone separator. The coarse material (0.075-1.18mm) at the bottom of the classifier can be used as a manufactured sand product. The cyclone separator separates the fine powder from the gas. The fine powder enters the next process, while the gas enters the circulating fan. After passing through the circulating fan, part of the gas returns to the vertical roller mill, and part is discharged into the atmosphere through chimney 31, completing the de-powdering process. The above embodiment is applicable to process systems where the moisture content of the powder particles is less than 2.5%.

[0185] In a vertical roller mill, the ground and pre-sorted powder particles move downwards under gravity and are discharged through the bottom outlet of the pre-sorting section. They then enter a vibrating screen, where they are sieved to obtain a mixed manufactured sand product with a particle size smaller than a certain value. Simultaneously, the fine powder at the outlet of the vertical roller mill is carried upwards by the airflow. Under the action of the air classifier, harmful fine powder is separated and removed before proceeding to the next process.

[0186] This technology replaces the original cone crusher, dual rotor sand making machine, vertical shaft impact crusher, etc., reducing the content of needle-shaped and flaky particles in the product, reducing the fine powder content of manufactured sand, improving the product quality of manufactured sand, improving the energy utilization rate of sand making, reducing production energy consumption, facilitating large-scale production, improving resource utilization, improving concrete performance, and improving project quality.

[0187] Example 6

[0188] Please refer to Figure 24. Unlike Embodiment 4, the outlet of the circulating fan in this embodiment is also provided with a dust collector 28 and a tail exhaust fan 29 in sequence.

[0189] Part of the gas passing through the circulating fan 24 enters the dust collector. After dust removal by the dust collector, it is then discharged into the atmosphere via the tail exhaust fan and chimney 31. The dual-fan system consisting of a circulating fan and a tail exhaust fan enhances the on-site dust collection effect, reducing the dust emission concentration to 5 mg / m³. 3The following features achieve ultra-clean emissions, which is beneficial to environmental protection. Simultaneously, the exhaust fan facilitates the adjustment of circulating air volume, especially when the moisture content of the feed powder particles exceeds 2.5%, and the finished product has high moisture content requirements (e.g., manufactured sand for dry mortar with a moisture content of less than 0.5%). This allows for the discharge of humid air, reducing condensation within the system and extending pipeline lifespan. Alternatively, hot air can be connected in series before sorting to dry the powder particles after grinding in the vertical mill, preventing moisture condensation from affecting the entire circulation system.

[0190] Example 7

[0191] Unlike Embodiment 4, as shown in Figure 25, the vibrating screen 26 in this embodiment has several layers of screens with different apertures. The screens can be configured as one or more layers, allowing for step-by-step screening to meet the needs of multiple products.

[0192] In this embodiment, the vibrating screen has two layers of screens. The upper screen has an aperture of 4.75 mm, and the lower screen has an aperture of 2.36 mm. Particles larger than 4.75 mm above the upper screen are returned to the roller mill for further grinding. Particles between 2.36 and 4.75 mm are used as coarse sand. Particles smaller than 2.36 mm are used as medium and fine sand. The advantage of this technology is that it can produce manufactured sand products of different particle sizes, improving production efficiency and reducing enterprise operating costs.

[0193] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vertical roller mill, comprising a grinding section, the grinding section including a grinding disc and grinding rollers, characterized in that: Includes a pre-grinding section and an adaptive feed adjustment section; The pre-grinding section includes: a feeding center shaft, which is located above the grinding disc and is used to guide the material to be ground to the center of the grinding disc; grinding units, N grinding units evenly distributed around the feeding center shaft, each grinding unit having a pre-grinding section that contacts the grinding end face of the grinding disc; and an adaptive material blocking adjustment section including: a rocker arm sealing frame, which forms a support for mounting the grinding roller, the exterior of which is mounted on the frame of the roller mill via a rocker arm, and the interior of which the grinding roller is mounted; a material blocking device, which includes a fixed material blocking device and a sliding material blocking device that is vertically movable and connected to the fixed material blocking device, the fixed material blocking device and the sliding material blocking device forming a enclosure structure around the grinding roller; and a linkage assembly, which is connected to the rocker arm sealing frame and the sliding material blocking device, the internally moving upward rocker arm sealing frame driving the sliding material blocking device to move upward via the linkage assembly.

2. The vertical roller mill according to claim 1, characterized in that: The pre-grinding section includes a pressurizing device connected to the grinding unit and applying pressure to the grinding unit against the grinding end face of the grinding disc.

3. The vertical roller mill according to claim 2, characterized in that: The grinding units are radiating outwards from the feeding center axis and are evenly distributed above the grinding disc; the grinding units are located between the roller gaps of the vertical roller mill.

4. The vertical roller mill according to claim 3, characterized in that: The grinding unit includes a support shaft and a pre-grinding roller body. The axis of the support shaft is horizontally arranged. The pre-grinding roller body is provided with a pre-grinding section that contacts the grinding end face of the grinding disc. The pre-grinding roller body is fixed by one end of the support shaft, and the other end of the support shaft is connected to the feeding center shaft.

5. The vertical roller mill according to claim 4, characterized in that: The pressurizing device is arranged around the outside of the feeding center shaft. The upper end of the pressurizing device is fixed to the upper part of the feeding center shaft, and the lower end of the pressurizing device is connected to the support shaft of the grinding unit. The pressurizing device applies vertical downward pressure to the support shaft.

6. The vertical roller mill according to claim 5, characterized in that: An axially sliding sleeve is fitted at the lower end of the feeding center shaft, the end of the support shaft is fixed to the sliding sleeve, the feeding center shaft is provided with a flange, and the pressure device is a compression spring provided between the flange of the feeding center shaft and the sliding sleeve.

7. The vertical roller mill according to claim 1, characterized in that: The fixed baffle is disposed above the grinding disc and is arranged in segments along the outer edge of the grinding disc; the sliding baffle is embedded in the fixed baffle and the width of the sliding baffle is smaller than the width of the fixed baffle.

8. The vertical roller mill according to claim 1, characterized in that: The linkage assembly includes a fixed bracket, a lever connecting rod, and a lifting connecting rod. The fixed bracket is installed on the housing of the vertical roller mill. The fixed bracket is fitted with a lever pin through a long slot. The lever connecting rod is connected to the lever pin. One end of the lever connecting rod is hinged to a rocker arm sealing frame. The other end of the lever connecting rod is hinged to the upper end of the lifting connecting rod. The lower end of the lifting connecting rod is hinged to the sliding stop device.

9. The vertical roller mill according to claim 7, characterized in that: The corresponding contact surfaces of the sliding stop device and the fixed stop device are provided with magnets to make the contact surfaces fit together. The fixed stop device is provided with an inner vertical side stop surface. The outside of the fixed stop device is provided with a slope surface, which is an inclined surface formed from the inside to the outside.

10. A manufactured sand production system, characterized in that: The invention includes the vertical roller mill as described in any one of claims 1-9, as well as a raw material buffer silo, a classifier, a vibrating screen, and a powder removal mechanism; the powder removal mechanism includes a cyclone separator and a circulating fan; the outlet of the raw material buffer silo is connected to the feed inlet of the vertical roller mill; the discharge outlet of the vertical roller mill is connected to the vibrating screen; the vibrating screen returns the powder particles on the screen to the vertical roller mill via an elevator; the air outlet of the vertical roller mill is connected to the inlet of the classifier; the air outlet of the classifier is connected to the cyclone separator; and the air outlet of the cyclone separator is connected to the circulating fan.

Images