Why vertical roller mill production is getting lower and lower?

Why vertical roller mill production is getting lower and lower?

Vertical roller mill is a grinding equipment that integrates drying, grinding, powder selection and conveying. It is favored by users because of its small footprint. However, many people have reported that after using the equipment for a period of time, the output is not as good as before, which directly affects the economic benefits. Xiaobian and everyone to look at the factors affecting the vertical roller mill output and how to prevent production decline.

First, Grinding roller and disc liner wear

When the Vertical roller mill work, the grinding pressure is applied by the grinding roller, and the material is subjected to the action of pressing and shearing of the grinding roller and the grinding disc to achieve the purpose of grinding the material, so the wear of the grinding roller surface and the grinding disc surface liner is inevitable. As the grinding time is prolonged, the wear of the lining plate will be more serious. The gap between the grinding roller and the grinding disc will become the inner small outer large or uneven shape, the grinding efficiency will be greatly reduced, and the grinding output will be greatly reduced.

In this case, the wear of the lining should be checked regularly. When the grinding roller and the disc lining wear to a certain extent, it must be replaced in time to avoid the vibration or other problems affecting the Vertical roller mill operation due to the wear of the lining. The wear of the lining plate should be checked and treated in time. The lining plate can be changed and the height of the retaining ring can be lowered to extend the service life of the lining.

Two,Wear of the retaining ring

The purpose of the wear ring is to allow the material to be fully milled on the disc. If the retaining ring is worn or dropped, it will inevitably reduce the thickness of the layer, and the vibration of the mill will become larger. The coarse powder will not be fully ground and the grinding disc will be pulled out under the action of centrifugal force, which will increase the amount of returning and the total amount of grinding. It has also been increased, which can only reduce the Vertical roller mill output, and the vibration is large, and it is easy to jump and affect the operation of the mill. Therefore, it is necessary to check the retaining ring regularly and find out the problem in time.

Three,Nozzle ring wear

The main function of the spout ring is to change the wind direction through the guide vanes to ensure that the airflow is spiraled upwards and the material is taken away. If the spout ring is worn or partially worn, the airflow will be disordered, and a stable swirling upward airflow will not be formed, and the wind speed will also be reduced. The material cannot be taken away in time, returning to the scraping disc or the bottom scraping chamber of the nozzle ring to increase the circulation amount. Mill output

Four,Performance of the material being ground

1. The hardness of the material to be milled is large. For example, the high silicon material has poor grindability. In order to achieve qualified raw materials, it is bound to prolong the grinding time of the material and increase the internal circulation of the grinding. The materials in the grinding can not be discharged in time, and only the production can be reduced. .

2, the material size of the grinding material is too large, it will increase the number of grinding, the circulation amount increases, the pressure difference is high, it is difficult to grind, and it will also cause large vibration and unbalanced operation.

Therefore, according to the actual conditions of the raw materials of various manufacturers, according to the wearability and grain size of the materials, the operation of the mill is controlled to avoid affecting the output.

Five,System leakage

Leakage of the mill body will inevitably result in a small pressure difference and insufficient wind speed. The powder can not be taken away in time, affecting the mill output. In addition, other parts of the system will leak air, and the wind speed will decrease, which will cause the pipeline to accumulate. After the pipeline is accumulated, the ventilation area will become smaller, and the insufficient air volume will also affect the mill output. Therefore, it is necessary to check the air leakage problem of the processing system in time.

Six,Layer thickness

After the material is fed into the grinding disc, a certain layer is formed. When the thickness of the layer reaches a certain thickness, the grinding roller starts to grind. If the material layer is too thin, the grinding stress is too concentrated, and the grinding ability is reduced, which will inevitably lead to impact of the grinding roller liner and the grinding disc liner. The grinding machine has large vibration, easy to jump, and will damage the liner, the tension rod, etc. Can not be controlled by thin layer. If the thickness of the material layer is too thick, the grinding force will be converted into lateral stress, and the sliding shear will be formed between the materials. The slump of the material bed will increase, the milling efficiency will decrease, and the vibration will be large. The material will not be timely. Grinding and extruding the grinding disc, falling to the spout ring, increasing the circulation amount, the pressure difference is large, the material can not be ground away in time, forming a vicious circle, which can only reduce the production operation and affect the mill output.

The thickness of the layer is generally controlled to be about 50-80 mm. The principle is that the material fed into the mill should be ground in time and flow down in time. The pressure difference of the system should not be too high to ensure that the vibration is within a reasonable range.

In addition to the above factors, there are still many factors affecting the vertical roller mill output. For example, the mixture structure leads to material segregation, air volume control, hot air temperature control, batching control, etc., which will affect the vertical roller mill output. In actual production, it should be analyzed according to the specific conditions of the factory.