5 major precautions for vertical roller mill operationSeptember 27, 2019

Summary:Improve the cleanness of lubrication system in crushing and grinding equipment in beneficiation plant can ensure the smooth of lubricating oil circuit and the normal lubrication of the friction pairs

5 major precautions for vertical roller mill operation

With the improvement of the requirements of the grinding equipment in the industry, the Vertical roller mill has been familiar, accepted and recognized by its strong advantages, and has gradually become the preferred material for cement raw meal milling equipment. However, many operators are not familiar with the running process and operating steps of the vertical roller mill, which often causes many adverse effects. SBM heavy machine is deeply worried about this phenomenon, so this article is dedicated to those friends who are not very familiar with the vertical roller mill.

Maintaining a stable bed, which is the basis for the grinding of the roller abrasive bed, is the key to normal operation. The thickness of the layer can be adjusted by adjusting the height of the retaining ring. The appropriate thickness and their correspondence with the mill output should be found first in the commissioning phase. If the layer is too thick, the grinding efficiency is lowered, and the layer is too thin to cause vibration. If the rolling pressure is increased, the fine powder is generated, the material layer will be thinned; the rolling pressure is reduced, the grinding disc material becomes thick, and the corresponding materials are returned, and the material layer becomes thick. The internal wind speed is increased, the internal circulation is increased, the material layer is thickened, the wind speed is reduced, the internal circulation is reduced, and the material layer is thinned. The thickness of the bed after compaction of the roller mill by normal operation is not less than 40 to 50 ram.

timg (2)

Grinding pressure is a major factor affecting mill output, grinding efficiency and mill power. The vertical roller mill pulverizes the material by applying high pressure to the material bed. The pressure increases the output, but it does not change after reaching a certain critical value. The increase of the pressure is followed by the increase of power, resulting in unit energy consumption. The increase, so the appropriate roll pressure requires both production and energy consumption. This value is determined by the nature of the material, the particle size and the amount of feed. In the trial production, it is necessary to find a suitable grinding pressure and a reasonable wind speed to form a good internal circulation, so that the material layer on the grinding disc is suitable and stable, and the grinding efficiency is high. In the production process, when the area of ​​the wind ring is constant, the wind speed is determined by the air volume.

Correspondence with production process capability to ensure the grinding effect.

The vertical roller mill is a drying and grinding system. The temperature of the grinding is a comprehensive indicator to measure whether the drying operation is normal. In order to ensure that the raw material is well dried, the moisture content of the milled material is less than 0.5%, and the outlet temperature of the mill is generally controlled to be about 90~C. If the temperature is too low, the moisture of the finished product is large, which reduces the grinding efficiency and the efficiency of the powder selection, which may cause condensation of the dust collection system; if it is too high, it means that the smoke is cooled and humidified insufficiently, which may also affect the dust collection effect.

The vertical roller mill mainly relies on airflow to carry animal material circulation. A reasonable wind speed can form a good internal circulation, so that the material layer on the disc is proper and stable, and the grinding efficiency is high. However, the air volume is determined by the wind speed, and the air volume is related to the feeding amount. If the feeding amount is large, the air volume should be large; otherwise, the air volume should be reduced. The air volume of the fan is affected by the resistance of the system and can be adjusted by adjusting the fan valve. The pressure drop of the mill, the negative pressure of the grinding, and the negative pressure of the grinding can all reflect the amount of wind. Large pressure drop and large negative pressure indicate that the wind speed is large and the air volume is large; otherwise, the corresponding wind speed is small. The stability of these parameters indicates the stability of the air volume, thus ensuring the stability of the bed.

The raw material fineness is affected by the separator rotation speed, the system air volume, and the internal load of the mill. In the case of constant air volume and load, the fineness can be adjusted by manually changing the speed. When the adjustment is increased or decreased by 2r/min each time, the vibration of the mill is increased or even tripped.

The above is the SBM heavy machine for those who are not very familiar with the operation of the vertical roller mill. There are many advantages of the vertical roller mill. I hope that the friends who need it should not negate the value and advantages of the unfamiliar operation of the vertical roller mill. If you have any questions, please feel free to consult our SBM heavy machine.