Wear Of Vertical Grinding Rollers And Discs

Vertical mills are widely used in industries such as cement, electric power, metallurgy, chemical industry, and non-metallic ore. They are used to grind bulk, granular and powdery raw materials into required powdery materials. With the continuous maturation and development of the vertical mill process, many manufacturers use vertical mills to grind cement in addition to raw mills, coal powder, and fine slag powder.

1.Easy grinding of materials and selection of grinding roller and grinding disc

Grinding rollers and discs are parts that are in direct contact with the material. If the abrasiveness of the material is poor, such as silica or shale, the liners of the grinding rollers and discs will be severely worn, causing uneven grooves and cracks. And broken edges.

Selecting easy-to-grind raw materials can objectively prevent excessive wear of the grinding rollers and discs, so choosing a pair of good-quality grinding rollers and discs can extend the service life subjectively to achieve the purpose of reducing production costs.

2. Whether the balance between the grinding rollers and the limit height are consistent

The balance between the grinding rollers refers to the fact that the four grinding rollers are placed on the grinding plate statically, and whether the center lines of the four grinding rollers are above the same horizontal line. This has a direct relationship with the flatness of the grinding plate installation and the grinding plate processing Accuracy is equally relevant. If it is unbalanced, the grinding wheel and the grinding roller which are closest to the grinding wheel under the condition of grinding pressure during the operation of the mill will wear quickly.

The height limit is precisely used to control the thickness of the material layer. When the limit height of our school is inconsistent, the thickness of the material layer on the grinding disc is also inconsistent. This will cause certain vibration and vibration during the operation of the mill. Exacerbation is one of the main factors causing wear. The limit height is inconsistent. The roller closest to the disc is subjected to the greatest force during the pressure grinding process, so the wear is also the fastest.

3. Whether the grinding tension pressure is too large and the material layer is too thin

In operation, we have to get used to the practice of increasing production pressure and reducing production pressure. In particular, in the process of reducing production, in order to stabilize the control and save the operation of many operators, it is generally difficult to reduce the excess tension. Or in the process of production control, the tension of the mill is always kept a little margin. In fact, this method can achieve the purpose of controlling troubles to a certain extent, but after a period of time you will find that the material layer on the grinding disc is continuously thinning, and the vibration of the mill is gradually increasing because of the grinding pressure. More than the feeding amount. The material layer is thin, the vibration is large, and the tensioning pressure is too high. These are undoubtedly the important factors that cause excessive wear of the grinding rollers and discs.

4.Prevent metal foreign matter from entering the mill

The most effective way to effectively prevent metal foreign matter from entering the mill is to use every iron remover in the system. General raw mill systems are equipped with two iron separators:

One is integrated into the top of the belt conveyor of the mill after the raw materials are blended, which functions to exclude the metal foreign objects brought in from the raw materials;

One should be above the belt conveyor after the feeding point of the outer circulation elevator or above the outer belt conveyor of the mill, to play the role of removing the metal falling out of the mill, such as the scraper of the mill, large bolts, etc.

Large or hard metal entering the mill will cause the mill to vibrate violently, causing the mill to stop, damage the reducer, and it is more likely that the foreign material on the mill will cause the bulk of the mill roll to fall off after being crushed by the mill. This situation is more terrible for the grinding rollers and discs than excessive wear. Therefore, it is very important to protect the mill with a good iron remover to minimize the possibility of metal foreign matter entering the mill.

5.Use and balance of nitrogen pressure

The nitrogen pressure must be set according to 60% to 70% of the actual grinding pressure. The main function of nitrogen airbags is to store energy and reduce vibration. Therefore, when using nitrogen pressure and grinding pressure, the above proportional relationship must be followed. High grinding pressure and low nitrogen pressure will cause vibration; high nitrogen pressure and low grinding pressure, and the grinding roller cannot overcome the rebound of nitrogen and also generates vibration. Reasonable use of nitrogen pressure and grinding pressure can effectively restrain this aspect of vibration and effectively prevent the wear of the grinding rollers and discs. At the same time, the nitrogen pressure between the nitrogen bladders must be the same, because the grinding pressure is the same. If the pressure between the nitrogen airbags is not the same, the dynamic effect between the grinding rollers will be different, and the vibration will be generated if the balance is broken. The chance of vibration and wear increases.

6.Prevent wear caused by plastic deformation caused by fatigue operation of grinding rollers and discs

All operating systems and equipment need a reasonable rest, otherwise fatigue will occur and overload operation will cause equipment accidents. Regardless of which production line, the configuration of the vertical mill has a certain amount of surplus, so we must adjust the storage location during the production process, regular inspection of the vertical mill system, and allow a certain time for the mill to rest. According to the moisture content of the raw and combustible materials, when the temperature of the material to be ground and the drying capacity can meet the requirements, reduce the temperature of the grinding as much as possible, because the higher the temperature of the metal, the greater the probability of plastic deformation. Then, a grinding roller in operation with great tension has plastic deformation and its wear is very blocky. Because the wear of the grinding roller also aggravates the wear of the grinding disc.

In fact, the wear of the grinding rollers and discs is objectively an intangible consumption. In ordinary operation, it is invisible and invisible, so it is easy for everyone to forget the existence of this consumption. To prevent the grinding rollers and discs from wearing too fast, attention needs to be paid to details in production and timely maintenance.

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