Vibration During Vertical Mill Production

Characteristics and Cause Analysis of Vibration of Vertical Mill

As the mainstream equipment for milling, vertical mills have a direct relationship with the interests of enterprises. The vibration produced by the vertical mill not only damages the equipment, but also often raises and lowers the rollers, which also causes instability in the table and affects the output. The vibration of the vertical mill is related to many factors such as transmission, material layer, foreign matter, roller surface, grinding disc, particle size, pressure and so on.

1. Vibration caused by transmission

The transmission part of the vertical mill includes a motor, a coupling, and a reducer. Any failure in any of these links can cause vibration. If the installation accuracy of the coupling is insufficient, that is, the centering error is large, it will cause the vibration mainly composed of axial vibration; if the motor rotor and the stator do not coincide, the alternating magnetic field will pull the rotor back and forth with the change of the magnetic field direction, thereby Causes axial vibration; damage to the reducer bearings, gear broken teeth, etc. will cause vibration of the mill.

2. Vibration caused by unstable material layer

When the material layer is unstable, the distance between the grinding roller and the grinding disc continuously changes. When the grinding roller is high and low, the vibration of the mill is caused. The material is too dry or too thin, the height of the retaining ring is not suitable, the feeding is unstable, or the material flow rate on the grinding plate is too fast, which will cause the material layer to be unstable.

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3. The particle size is too large to cause vibration

The particle size of the raw material is too large. If it exceeds the thickness of the material layer, the roller will suddenly lift and fall when the roller passes, causing the mill to vibrate. This type of vibration is determined by the number of large pieces and the fragility of the material.

4. Vibration caused by passing iron

When foreign objects such as iron nuggets enter the mill, the rollers cannot crush them, causing the rollers to fluctuate and cause vibration of the mill; if foreign objects are circulated in the system, they will cause vibration within the cycle time. Near the stop ring, its vibration frequency is the product of the mill speed and the number of rollers.

5. Vibration caused by out-of-round grinding rollers

The slag or block of the wear layer of the vertical mill's wear roller appears, the roller will be out of round, and it will rise and fall suddenly once every rotation, forming a regular vibration.

6. The grinding disc is broken or severely flaking

When the grinding plate liner is broken or severely peeled off, the grinding plate will be uneven, and the grinding roller will sink suddenly every time here, causing vibration. The vibration frequency is the product of the mill speed and the number of rollers.

7. Improper operation causes vibration

When the wind speed of the wind ring is too high, the discharge outside the mill is reduced, and the materials that need to be circulated are turned over again on the grinding disc. Too many powdery materials form an unstable layer, the pressure difference in the mill rises, and the vertical mill generates vibration; Poor abrasiveness, the rotating speed of the powder separator is too high, and there is a lot of fine powder returned to the grinding disc, which causes the material layer to be unstable, the pressure difference in the mill to rise, and the mill to vibrate. This type of vibration is related to the operation, and the vibration period is related to the operation adjustment frequency.

8. Roller pressure is too low

When the roller pressure is too low, it is difficult to crush the block-shaped material, and the undulation of the grinding roller hits the grinding disc, and vibration is unavoidable.

The above explains the causes of vibration in the production of vertical mills. If you encounter such a failure, you should find the cause and the corresponding solution to resume normal production.

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