A ball mill inlet and outlet end cover
By installing a steel plate isolation structure between the end liners of the inlet and outlet end caps of the ball mill, the slurry circulation path is blocked, solving the problems of end cap wear and bolt breakage, and achieving stable operation and improved safety of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI PROVINCE LUJIANG LONGQIAO MINING
- Filing Date
- 2025-08-07
- Publication Date
- 2026-07-21
AI Technical Summary
The end caps at the inlet and outlet of the ball mill suffer severe wear due to the "water ring" formed between the slurry and the end liner, which affects the safe operation and production stability of the equipment and is prone to bolt breakage and slurry leakage.
Steel plates are placed between the end liners to form an isolation structure, blocking the slurry circulation path. The steel plates are fixed by segment welding to enhance the welding strength and reduce the heat-affected zone, thus preventing end cap wear.
It effectively prevents end cap wear, reduces bolt breakage and grout leakage, improves equipment operation stability, reduces downtime and maintenance costs, and enhances safety.
Smart Images
Figure CN224524898U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of mineral processing technology and relates to an end cover for the feed and discharge ends of a ball mill. Background Technology
[0002] Ball mills, as a common type of industrial machinery, are widely used in various industries such as cement, silicate products, metal ore beneficiation, and glass ceramics, primarily for grinding, refining, or mixing materials. The Longqiao Mining Beneficiation Plant has six ball mills, including three for primary grinding, two for secondary grinding, and one regrinding unit. The primary grinding unit uses bimetallic liners, while the secondary grinding and regrinding units use magnetic liners.
[0003] During actual operation, significant wear was observed in the inlet and outlet end covers of a ball mill. The main reason was that multiple end liners were bolted to the inside of these end covers, creating gaps between them. During mill operation, slurry entered these gaps, forming a "water ring" between the end liners and end covers, causing continuous circulation of the slurry within this area. This prolonged circulation not only accelerated the wear of the end covers but could also lead to more serious subsequent problems.
[0004] Specifically, over time, the wear on the end caps becomes increasingly severe, affecting not only the efficiency of subsequent liner replacements but also threatening the safe operation of the equipment. Furthermore, the "water ring" formed during operation wears down the bolts used to install the end liners, causing them to break or fall off, leading to slurry leakage and significantly disrupting the production process. Moreover, when a malfunction occurs, since ball mills typically contain water and ore, immediate shutdown causes these materials to settle and harden inside the equipment, requiring approximately 20 minutes of idling before a safe shutdown. These problems are particularly frequent as the bimetallic liners near the end of their service life, severely impacting production stability and continuity, while increasing the operating costs of the concentrator. Slurry leakage not only significantly impacts on-site management but also increases the workload of operators and creates safety hazards during cleanup. Summary of the Invention
[0005] This application provides an end cover for the inlet and outlet of a ball mill, which adjusts the gap between the end liners and uses steel plates to fill the gap, making the interior of the end cover flat and providing good wear resistance.
[0006] To achieve the above technical objectives, the technical solution adopted in this application is as follows: a ball mill inlet and outlet end cover, including an end cover body, and an inner ring end liner assembly and an outer ring end liner assembly installed on the inner side of the end cover body;
[0007] The inner ring end liner assembly includes several inner ring end liners, which are arranged in a ring around the center of the end cap; there is a first gap of 15-20mm between any two adjacent inner ring end liners.
[0008] The outer ring end liner assembly includes several outer ring end liners, which are arranged in a ring around the end cap, and are located outside the inner ring end liner; that is, the outer ring end liner assembly and the inner ring end liner assembly are installed concentrically, and the outer ring end liner assembly is located outside the inner ring end liner assembly; there is a second gap of 15-20mm between any two adjacent outer ring end liners.
[0009] The first gap is filled with a first steel plate, one end of which is aligned with the minimum inner diameter of the inner ring end liner and the other end of which is aligned with the minimum inner diameter of the outer ring end liner; the second gap is filled with a second steel plate, one end of which is aligned with the maximum inner diameter of the inner ring end liner and the other end of which is aligned with the maximum inner diameter of the outer ring end liner.
[0010] As an improved technical solution of this application, the inner ring end liner has a fan-shaped structure, specifically a first fan-shaped steel plate with an included angle of 22.5°.
[0011] As an improved technical solution of this application, the outer ring end liner has a fan-shaped structure, specifically a second fan-shaped steel plate with an included angle of 22.5°.
[0012] As an improved technical solution of this application, the thickness of the inner ring end liner is 120mm.
[0013] As an improved technical solution of this application, the outer ring end liner has a thickness of 80mm.
[0014] As an improved technical solution of this application, the thickness of the first steel plate is 6-10mm.
[0015] As an improved technical solution of this application, the thickness of the second steel plate is 6-10mm.
[0016] As an improved technical solution of this application, the first steel plate or the second steel plate is fixed to the end cap body by segment welding.
[0017] As an improved technical solution of this application, all outer ring end plates are in a ring structure, and each individual outer ring end plate is an independent arc-shaped sector. The arc-shaped sector has two evenly distributed outer ring end plate holes, which are arranged along the circumferential direction of the arc-shaped sector.
[0018] As an improved technical solution of this application, all inner ring end plates are in a ring structure, and each individual inner ring end plate is an independent arc-shaped sector. The arc-shaped sector has two evenly distributed inner ring end plate holes, which are arranged along the axial direction of the arc-shaped sector. Beneficial effects
[0019] 1. Effectively prevents end cap wear
[0020] By setting isolation steel plates between end liners (between inner ring end liners and between outer ring end liners), the formation path of the slurry "water ring" was successfully blocked, which effectively protected the end cap part that was originally easily eroded by the slurry and greatly extended the service life of the end cap.
[0021] 2. Reduce bolt breakage and grout leakage.
[0022] With the elimination of the "water ring," problems such as bolt breakage and detachment, which were frequently caused by the scouring of the "water ring," have been greatly reduced, thus effectively preventing slurry leakage and ensuring production continuity and safe equipment operation.
[0023] 3. Improve equipment uptime and reduce downtime.
[0024] Existing technologies often experience frequent malfunctions in the later stages of use, frequently requiring emergency repairs and shutdowns with the mill running dry. Adopting this method significantly improves equipment operational stability, increases overall operating efficiency, and reduces the operating costs of the ore dressing plant.
[0025] 4. Reduce maintenance costs and labor intensity
[0026] End cap wear is reduced, maintenance frequency decreases, grout leakage is reduced, on-site cleaning workload is significantly reduced, and the labor intensity of operators is reduced.
[0027] 5. Enhance safety and eliminate potential safety hazards
[0028] With reduced grout leakage and improved site cleanliness, the personal safety risks to workers during daily inspections and cleaning processes are also reduced, effectively avoiding safety accidents caused by grout leakage. Attached Figure Description
[0029] Figure 1 A schematic diagram of the inner side of the end cap of the technical solution of this application;
[0030] Figure 2 yes Figure 1 A partially enlarged schematic diagram of the gap between the middle and outer ring end liner plates and the outer ring end liner plate;
[0031] Figure 3 yes Figure 1A partially enlarged schematic diagram of the gap between the inner ring end liner and the inner ring end liner;
[0032] Figure 4 This is a side view of the end cap structure of the technical solution of this application;
[0033] Figure 5 yes Figure 4 A magnified view of the structure at point A in the middle;
[0034] In the diagram, 1 is the ball mill end cover; 2 is the inner ring end liner; 3 is the inner ring end liner fixing bolt; 4 is the outer ring end liner; 5 is the outer ring end liner fixing bolt; 6 is the second steel plate; 7 is the segment weld point; and 8 is the first steel plate. Detailed Implementation
[0035] This application adds a steel plate between two adjacent end liners (between inner end liners and between outer end liners) to effectively block the "water ring" formed by the circulation of slurry between the end liners and the end caps, thereby preventing continuous wear of the end caps and bolts.
[0036] By dividing the end cap area into multiple independent small zones using steel plates, physical isolation is achieved, fundamentally solving the corrosion problem caused by long-term slurry erosion. Furthermore, segmented welding is employed to weld the steel plates, ensuring weld strength while reducing the heat-affected zone and lowering the risk of end cap deformation.
[0037] This end cover structure includes: a ball mill end cover 1; an inner ring end liner 2; inner ring end liner fixing bolts 3; an outer ring end liner 4; outer ring end liner fixing bolts 5; and a steel plate. The ball mill end cover 1 serves as the main support structure for the inlet and outlet ends; the inner ring end liner 2 is a liner plate close to the inside of the ball mill cylinder; the inner ring end liner fixing bolts 3 are used to fix the inner ring end liner plate to the ball mill end cover; the outer ring end liner 4 is another liner plate concentric with the inner ring end liner 2 and located outside the inner ring end liner 2; the outer ring end liner fixing bolts 5 are used to fix the outer ring end liner 4 to the ball mill end cover 1; and the steel plate is welded between adjacent end liners (including the inner ring end liner and the outer ring end liner, extending to the junction of the inner and outer ring end liners), serving to prevent the formation of a water ring.
[0038] like Figure 1-5 As shown, a ball mill inlet and outlet end cover includes an end cover body, and an inner ring end liner assembly and an outer ring end liner assembly are installed on the inner side of the end cover body.
[0039] The inner ring end liner assembly comprises several inner ring end liner plates 2, arranged in a ring around the center of the end cap. Specifically, each inner ring end liner plate 2 has a fan-shaped structure, forming a first fan-shaped steel plate with a 22.5° included angle. Therefore, each inner ring end liner plate 2 has an arc with a minimum inner diameter and an arc with a maximum inner diameter, both with the same included angle. The ring structure with a 22.5° included angle formed by connecting the two ends of the arc with the minimum and maximum inner diameters constitutes the shape of the inner ring end liner plate 2. Because the inner ring liner plates are cast using molds, their precision is relatively low. Therefore, there is a first gap of 15-20mm between any two adjacent inner ring end liner plates 2. During installation, all inner ring end liner plates 2 form a ring structure. Each individual inner ring end liner plate 2 is an independent arc-shaped sector, with two evenly distributed outer ring end liner plate holes on the arc-shaped sector. The ring end liner plate holes are arranged along the axial direction of the arc-shaped sector.
[0040] The outer ring end liner assembly comprises several outer ring end liner plates 4, arranged in a ring around the end cap, and positioned outside the inner ring end liner plates; specifically, the outer ring end liner plates 4 have a fan-shaped structure, specifically a second fan-shaped steel plate with a 22.5° included angle. The outer ring end liner assembly is installed concentrically with the inner ring end liner assembly, and the outer ring end liner assembly is located on the periphery of the inner ring end liner assembly; a second gap of 15-20mm is formed between any two adjacent outer ring end liner plates 4. During installation, all outer ring end liner plates 4 form a ring structure, with each individual outer ring end liner plate 4 constituting an independent arc-shaped sector. Each arc-shaped sector has two evenly distributed outer ring end liner plate holes, arranged along the circumference of the arc-shaped sector.
[0041] To completely sever the first gap, the second gap, and the annular gap between the inner and outer ring end liner plates, a first steel plate 8 is filled into the first gap. One end of the first steel plate 8 is aligned with the minimum inner diameter of the inner ring end liner plate 2, and the other end is aligned with the minimum inner diameter of the outer ring end liner plate 4. A second steel plate 6 is filled into the second gap. One end of the second steel plate 6 is aligned with the maximum inner diameter of the inner ring end liner plate 2, and the other end is aligned with the maximum inner diameter of the outer ring end liner plate 4. This ensures that after installation, the first steel plate 8 and the second steel plate 6 can extend out of the first and second gaps and reach the junction of the inner ring end liner plate 2 and the outer ring end liner plate 4.
[0042] Furthermore, the first and second gaps are staggered to avoid the first steel plate 8 and the second steel plate 6 being on the same straight line. This facilitates the installation of the first steel plate 8 and the second steel plate 6 and avoids stress concentration caused by excessive welding on a straight line.
[0043] The inner ring end liner 2 is 120mm thick. The outer ring end liner 4 is 80mm thick.
[0044] To match the first gap, the thickness of the first steel plate 8 is 6-10 mm. To match the second gap, the thickness of the second steel plate 6 is 6-10 mm.
[0045] As an improved technical solution of this application, the first steel plate 8 or the second steel plate 6 is fixed to the end cap by segment welding.
[0046] In actual installation, since the end liner plates (inner ring end liner plate 2 / outer ring end liner plate 4) are installed in multiple small pieces, there will be gaps between each pair of adjacent liner plates. The steel plates (first steel plate 8 / second steel plate 6) are placed between two end liner plates (any two adjacent inner ring end liner plates 2, or any two adjacent outer ring end liner plates 4), and welded and fixed to the inlet / outlet end caps perpendicular to the end liner plates. After each steel plate is welded, the next inner ring end liner plate 2 / outer ring end liner plate 4 is installed, and so on, until all inner ring end liner plates 2 / outer ring end liner plates 4 and the first steel plate 8 / second steel plate 6 are installed. This method effectively blocks the slurry water ring formed between the inlet / outlet end caps and the inner / outer ring end liners during ball mill operation. By dividing the end cap area into multiple independent small zones using steel plates, the slurry circulation path is cut off, preventing continuous erosion and wear on the inner / outer ring end liners and their fixing bolts. Practical application has verified that this modification fundamentally solves the wear problem caused by the "water ring" erosion of the inlet / outlet end caps, while effectively avoiding the risk of wear and breakage of the connecting bolts between the inner / outer ring end liners and the end cap body, significantly improving the stability and reliability of the equipment operation.
[0047] Specifically:
[0048] 1. Clean the end cover surface: Before installation, thoroughly clean the ball mill inlet and outlet end covers to remove oil, rust and other impurities, and ensure that the welding surface is clean.
[0049] 2. Synchronously install the inner ring end liner 2 and the outer ring end liner 4: The inner ring end liner 2 and the outer ring end liner 4 are simultaneously installed to the corresponding positions on the end cap. That is, in the same circumferential direction, the inner ring end liner 2 and the outer ring end liner 4 are installed sequentially, maintaining a consistent relative position between them (with a certain degree of misalignment), and are initially tightened using the corresponding fixing bolts (inner ring end liner 2 is fitted with inner ring end liner fixing bolt 3 in the inner ring end liner hole, and outer ring end liner 4 is fitted with outer ring end liner fixing bolt 5 in the outer ring end liner hole). The second step only performs initial fixing, and the bolts are not fully tightened yet, so that the first steel plate 8 / second steel plate 6 can be inserted and adjusted later.
[0050] 3. Inserting and segmentally welding the steel plate: Insert a steel plate between two adjacent inner ring end liners 2 and between two outer ring end liners 4 (generally, there is a gap of about 15-20mm between each pair of adjacent inner ring end liners 2 and outer ring end liners 4). This steel plate is positioned between inner ring end liners 2 and between outer ring end liners 4, extending to the junction of inner ring end liners 2 and outer ring end liners 4 to achieve full-area isolation. The steel plate is welded to the end cap using segmental welding, i.e., welding is performed in segments along the edge of the steel plate. The segmental weld points 7 are controlled to ensure that each segment is 50-100mm long and spaced approximately 100mm apart, ensuring weld strength while avoiding deformation due to thermal stress.
[0051] 4. Complete the installation of the remaining inner ring end liner 2, outer ring end liner 4 and steel plate in sequence: Continue to install the remaining inner ring end liner 2 and outer ring end liner 4 in the above manner, and insert steel plate between each group of inner ring end liner 2 / outer ring end liner 4 and perform segment welding until the installation of all inner ring end liner 2 and outer ring end liner 4 and steel plate on the entire inlet and outlet end cover is completed.
[0052] 5. Overall Inspection and Final Tightening: After all end liners and steel plates are installed, conduct a comprehensive inspection of the entire structure to confirm that the steel plates are firmly welded, the liners are tightly installed, and the bolt connections are reliable. Finally, tighten all fixing bolts.
[0053] 6. Trial Operation and Maintenance: After installation is complete and the ball mill cylinder liner is installed, close one manhole door of the ball mill, and then add steel balls through the other manhole door. After adding the steel balls, close the other manhole door and conduct a water injection test. If there is no leakage, start the ball mill for no-load trial operation and observe for any abnormal vibrations. After normal operation, run it under heavy load and check for any slurry leakage. If everything is normal, it can be put into normal use, and the wear of the welded steel plates and liners should be inspected regularly.
Claims
1. An end cap for the inlet and outlet of a ball mill, characterized in that, Includes an end cap body, and an inner ring end liner assembly and an outer ring end liner assembly are installed on the inner side of the end cap body; The inner ring end liner assembly includes several inner ring end liners, which are arranged in a ring around the center of the end cap; there is a first gap of 15-20mm between any two adjacent inner ring end liners. The outer ring end liner assembly includes several outer ring end liners, which are arranged in a ring around the end cap, and are located outside the inner ring end liner; that is, the outer ring end liner assembly and the inner ring end liner assembly are installed concentrically, and the outer ring end liner assembly is located outside the inner ring end liner assembly; there is a second gap of 15-20mm between any two adjacent outer ring end liners. The first gap is filled with a first steel plate, one end of which is aligned with the minimum inner diameter of the inner ring end liner and the other end of which is aligned with the minimum inner diameter of the outer ring end liner; the second gap is filled with a second steel plate, one end of which is aligned with the maximum inner diameter of the inner ring end liner and the other end of which is aligned with the maximum inner diameter of the outer ring end liner.
2. The ball mill inlet / outlet end cover according to claim 1, characterized in that, The inner ring end liner has a fan-shaped structure, specifically a first fan-shaped steel plate with an included angle of 22.5°.
3. The ball mill inlet / outlet end cap according to claim 1, characterized in that, The outer ring end liner has a fan-shaped structure, specifically a second fan-shaped steel plate with an included angle of 22.5°.
4. The ball mill inlet and outlet end caps according to claim 1, characterized in that, The inner ring end liner is 120mm thick.
5. The ball mill inlet / outlet end cover according to claim 1, characterized in that, The outer ring end liner is 80mm thick.
6. The ball mill inlet and outlet end cap according to claim 1, characterized in that, The thickness of the first steel plate is 6-10mm.
7. The ball mill inlet and outlet end cap according to claim 1, characterized in that, The thickness of the second steel plate is 6-10mm.
8. The ball mill inlet and outlet end cap according to claim 1, characterized in that, The first steel plate or the second steel plate is fixed to the end cap body by segment welding.
9. The ball mill inlet and outlet end caps according to claim 1, characterized in that, All outer ring end plates are in a ring structure. Each individual outer ring end plate is an independent arc-shaped sector with two evenly distributed outer ring end plate holes arranged along the circumference of the arc-shaped sector.
10. The ball mill inlet and outlet end caps according to claim 1, characterized in that, All inner ring end plates are in a ring structure. Each individual inner ring end plate is an independent arc-shaped sector with two evenly distributed inner ring end plate holes arranged along the axial direction of the arc-shaped sector.