What is the importance of Coal Mill Roll maintenance

Coal Mill Roll is the main component in the vertical mill equipment, mainly responsible for the grinding of materials.
Under normal circumstances, the life cycle of the grinding roller is 500 hours, but this is not a standard. If the hardness of the material is high, the grinding roller may be used for a short time.
However, in general, the time is less than 500 hours. It is recommended that users do regular inspections and daily maintenance work, and try to extend the replacement cycle of the grinding rollers.​​

Coal Mill Roll

Roller Maintenance Precautions

1. Make sure the mill runs smoothly (such as checking the height of the retaining ring, etc.).
2. The retaining ring maintains the proper height and is uniform over the entire circumference.
3. Give proper pressure to the grinding roller through the hydraulic system.
4. Check the effectiveness of the air seal according to the operating instructions for the air seal piping.
5. When removing the entire grinding roll, the grinding roll must be turned out of the mill together with the rocker arm. At this time, the expansion sleeve should be loosened.
6. When assembling, pay attention to the correct position of the opening of the conical expansion sleeve connecting the roller shaft and the upper rocker arm. The opening of the conical expansion sleeve is blocked with a rope-like material, so that the sealed gas cannot get out, and the dust cannot get in.

Vertical roller mill is commonly known as vertical mill. Its working principle is that the grinding rollers with a certain pressure grind the materials that are relatively evenly distributed on the rotating grinding disc.
Because the grinding of the material layer can utilize the splashing power when a part of the material is crushed, and has the characteristics of low energy consumption, the vertical grinding mill is a medium-pressure material layer grinding.

After the material is pulverized to the required particle size, the material is sent to the storage hopper by the elevator, and then sent to the grinding chamber of the main vertical mill evenly and continuously by the vibrating feeder. Due to the centrifugal force during rotation, the Coal Mill Roll swings outward. , press tightly on the grinding ring, the shovel blade scoops up the material and sends it between the grinding roller and the grinding ring, and the grinding purpose is achieved due to the rolling of the grinding roller.
The fine powder after the material is ground is brought into the analyzer for sorting with the circulating air of the blower, and the material with excessive fineness falls back for regrinding. is the finished product.

Because there is a certain amount of water in the material to be ground in the vertical mill, heat is generated during grinding, water vapor is evaporated, and the pipes of the whole machine are not tightly connected, the outside air is sucked in, which increases the circulating air pressure and ensures that the mill is in a negative pressure state. The increased air flow is discharged into the dust collector through the residual air duct, and then discharged into the atmosphere after being purified.

When the vertical mill is working, the relatively uniform material from the feeding device is sprinkled on the rotating grinding disc, and is subjected to the rolling of the grinding roller and the grinding disc. The ground material and some unground materials gradually overflow under the action of centrifugal force. Grinding disc, and under the action of strong circumferential wind around the grinding disc, the overflowing material is lifted along the spiral direction of the cylinder wall and enters the classifier (powder separator) in the upper part of the working chamber, and the large particles fall on the grinding disc in the central area of ​​the working chamber. Accept rolling again. The flow direction, pressure, temperature, and flow density of the working chamber are all different, which is a typical complex flow constant composed of gas-solid two-phase flow.


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