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The cause and treatment of vibration failure of verticalmill

Date:2019-07-11 17:59     writer:cement editor     Views:

Vibration is the most important factor affecting vertical mill operation.The vibration of vertical mill is detected by vibration sensor of reducer (transverse and longitudinal mounted on reducer).Its measurements are converted into electrical signals that are fed to a computer.But if the adjustment is not good, once the amplitude exceeds the rating, it will automatically alarm until stop grinding.

1. Influence of material layer

 

The reason and treatment of thin layer


(1) small feeding quantity.The feed amount of the vertical mill must adapt to the capacity of the mill. Whenever the feed amount is lower than the rated output, the material layer will gradually become thinner, and the direct contact between the grinding roller surface and the grinding disc surface will cause vibration.

Treatment measures: immediately increase the amount of feeding, appropriately reduce the roll pressure, according to the increase of the thickness of the material layer, grasp the increase of the amount of feeding, after stabilizing the material layer about 50 mm, restore the roll pressure.

(2) when the material is of low hardness, good fragility and relatively high roll pressure, even if there is a material layer with a thickness of 30 mm ~ 50 mm, there is the possibility of air compression in an instant, thus causing vibration.

Treatment measures: appropriately reduce roll pressure, increase the amount of water spray, according to the grinding conditions increase the amount of feeding.

The reason and treatment of layer thickness


If the amount of feeding is too large, contrary to the thin material layer, the phenomenon of "plough material" will appear in the mill, forming a unstable material layer.The discontinuous contact between the grinding roller surface and the grinding disc surface causes vibration.

Treatment measures: immediately reduce roll pressure, reduce the amount of feeding, eliminate the "plough" phenomenon, according to the thickness of the material layer reduced, grasp the amount of feeding.

2. Particle size of grinding material


Roller mill is a multi-stage grinding, circular grinding, the grain size of the grinding material can be up to 5% of the diameter of the grinding roller, reasonable grain size gradation is also an important link to improve the output of the mill.The main purpose of setting up the external circulation of the large vertical roller mill is to adjust the grain size distribution of the grinding materials.

(1) into the grinding particle size greater than 40 mm Φ accounted for more than 80%, the material of the inner moisture decreases, and would not form good material layer, outside circulation increase, finally "full" grinding vibration.

Treatment measures: reduce the amount of feeding, increase the amount of water spraying, appropriately increase the roller pressure.

(2) had broken into the grinding material, particle size is less than 5 mm Φ accounted for more than 80%, can produce thin layer or "plough" phenomenon, caused by vibration.

Treatment measures: timely increase the amount of feeding or reduce roll pressure.

3. Grinding


The causes of full grinding of vertical mill generally include: too much feed, too fast speed of powder separator, too large internal circulation, too low roller, too large circulating load, or too little ventilation, which produces too much powder and exceeds the carrying capacity of gas through the mill. Finally, the material buries the roller and causes vibration.

Treatment measures: properly reduce the speed of the separator, increase the roller pressure, increase the air volume, and stabilize the mill working condition.

4. Metal or foreign body enters into the mill


Vertical roller grinding is a high-pressure operation, and the vibration of the mill will be caused by the loosening of bolts, the unwelding of bolts and the falling off of the wall board of the three-way lock air valve.When iron and other metal foreign bodies enter into the grinding, it may not only cause the collapse of the hardened layer of the grinding roller and disc, but also cause the impact of the pressure layer and cause vibration.

Treatment measures: install metal detector and iron remover before the material is grinded and at the proper position of the external circulation system to prevent metal and other foreign matters from being grinded. Always clean the iron remover to ensure the normal use of the iron remover.

Above is the author of the vertical roller mill operation vibration fault analysis, there are many reasons for vibration fault, here I simply listed a few, if you want to know more reasons, you can click on the online customer service or leave a message with us, we will immediately reply to you.

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