Introduction

Vertical grinding mill is a set of drying, grinding, powder selection and transportation in one of the grinding equipment. Because of its small footprint, it is favored by users. But many people feedback that after using the equipment for a period of time, the output is not as good as before, which directly affects the economic benefits.

1. Wear of liners of grinding roller and grinding table

When the vertical grinding mill works, the grinding pressure is exerted by the grinding roller, and the material is pressed and sheared by the grinding roller and the grinding plate to achieve the purpose of grinding the material. Therefore, the wear of the roller surface and the lining plate of the disc surface is inevitable. With the increase of milling time, the wear of liner will be more serious. The gap between the grinding roller and the grinding plate becomes small inside and large outside or uneven shape. Grinding efficiency will be greatly reduced, resulting in a significant reduction in vertical mill capacity.

In this case, the lining plate should be checked for wear regularly. When the wear of the grinding roller and the lining plate of the grinding disk reaches a certain degree, it must be replaced in time, so as not to affect the operation of the vertical grinding mill due to the large vibration caused by the wear of the lining plate or other problems. Wear of lining plate shall be checked and handled in time. The service life of the lining plate can be extended by changing the lining plate surface and properly adjusting the height of the retaining ring.

2. Wear of Ring Stopper

The function of the grinding stopper ring is to make the material be fully milled on the grinding plate. If the retaining ring is worn or dropped, the thickness of the material layer will be reduced and the vibration of the mill will be increased. When the coarse powder is not fully ground, it is thrown out of the grinding plate under the action of centrifugal force, which increases the amount of returned material and the total amount of grinding. In this way, the output of the vertical grinding mill can only be reduced, and the vibration is large, and it is easy to trip and stop, affecting the operation of the mill. Therefore, it is necessary to check the retaining ring regularly and deal with the problems in time.

3. Wear of Thrust Ring

The main function of the thrust ring is to change the wind direction through the guide vanes, to ensure that the air flow rotates upward and takes away materials. If the thrust ring is worn or partially worn, the air flow will be disordered, which will not form a stable upward flow. And the wind speed will also be reduced, so the material cannot be taken away in time, and it will return to the scraping chamber at the bottom of the grinding plate or the falling thrust ring, so as to increase the circulation and affect the mill capacity.

4. Performance of Input Material

1. The hardness of the grinding material is larger than that of the high silicon material. In order to reach the qualified raw material, it is bound to extend the grinding time of the material and increase the internal circulation of the mill. The material in the grinding mill cannot be discharged in time, so it can only reduce the production and operation.

2. If the size of the feed material is too large, the grinding times will be increased. With the increase of circulation. It has high pressure difference and difficult to grind. Furthermore, it will also cause large vibration and unbalanced operation.

According to the actual situation of raw materials of various manufacturers, therefore, the grindability and granularity of materials, the operation of the mill shall be well controlled so as not to affect the capacity.

5.  Air leakage of System

The air leakage of the mill will inevitably cause a small pressure difference. The wind speed is not enough, the powder cannot be taken away in time, which will affect the mill capacity. In addition, if there is air leakage elsewhere in the system, the wind speed will decrease, which will cause the pipeline to accumulate materials. After the pipeline accumulates material, the ventilation area will become smaller, and the insufficient air volume will also affect the mill output. Therefore, it is necessary to check and deal with the air leakage of the system in time.

6.  Material layer thickness

After the material is fed into the grinding plate, a certain material layer is formed. When the thickness of the material layer reaches a certain thickness, the roller begins to grind. If the material layer is too thin, the grinding stress is too concentrated, and the grinding capacity is reduced, it will inevitably lead to the impact of the roller liner and the disc liner. The mill has large vibration and is easy to jump, which will also damage the lining plate and tensile rod, so it cannot be controlled by thin material layer. If the thickness of the material layer is too thick, the grinding force will be converted into lateral stress. Sliding shear will also be formed between materials, the slump of the material bed will increase, the grinding efficiency will decrease, and the vibration will also be large. The material was not ground in time and extruded out of the grinding plate, falling into the thrust ring. Increase circulation, large pressure difference, materials cannot be timely ground away, forming a vicious cycle. It can only reduce the production and affect the output of the mill.

The thickness of the material layer is generally controlled at about 50-80mm. The principle is that the materials fed into the grinding mill can be ground in time and flow to the next process 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 many factors that affect the output of vertical grinding mill. For example, mixture structure leads to material segregation, air volume control, hot air temperature control, ingredient control, etc., which will affect the output of vertical grinding mill. In the actual production, it should be analyzed according to the specific situation of the factory and solved.

HCMilling(Guilin Hongcheng) is a well-known machinery and equipment manufacturer in Yangtang Industrial Park, Lingui District, Guilin, China. We mainly produces series of Raymond mill, ultrafine mill, vertical grinding mill, calcium hydroxide production line and wear-resistant product equipment. If you are interested in our grinding mill. More details please contact:

Tel:+86-0773-3568321 

E-mail: hcm@hcmilling.com