Hi my friends
What is the cause of the vibration verticall roller mill?
Thanks
gilesg
There are a number of reasons for high vibrations in vertical roller mills, such as:
1. Failure of the grout or cement material under the steel beams embedded in the foundation top, which allows oil to penetrate, further degrading the concrete. The anchor bolts, which are typically large in diameter, continue to exert force into the foundation, and the base starts to distort.
2. This distortion of the steel structure can lead to weld failures, which generates additional "looseness", and the vibration increases.
3. There are additional root causes which stem from the inevitable cold joints between pours in the foundation. These separations degrade the vibration damping apacity of the foundation.
We have done many foundation repairs and regrouts of vertical roller mills in cement plants as well as in power stations. Please contact us directly for further information.
Ted Krapkat
Feed rate too low, too high or changing too quickly. Particle size of feed too large or too small. Fluctuations in moisture content of mill feed Sudden change in overall hardness (grindability) of one or more of the the mill feed components.
Large fluctuations in the quantity of one of the component/corrective materials.
Table speed Separator efficiency and operation. (eg. too high internal circulation of fine material )
Air/gas flow & nozzle ring air/gas speed. Overheating of the mill. (eg. insufficient water injection for cooling or mill inlet temperature to high, in a raw mill. Or use of very hot clinker in a cement mill)
Sudden fluctuations in grinding aid. Incorrect dam ring height setting.
Grinding force/ballast (N2) pressure. Worn internals eg rollers and/or table. Tramp metal or foreign objects.
Hello Ashkan,
The most important factor which determines the level of vibration in a VRM is the thickness and consistency of the grinding bed. The bed thickness may be affected by the following variables;-
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Other factors which may cause vibrations are;-
There are probably a lot more, but these are some of the main factors which I have personally come across.
Regards,
Ted.